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freebsd/contrib/libpcap/gencode.c
Xin LI edc89b24f3 MFV: libpcap 1.4.0. 
MFC after:	4 weeks
2013-05-30 08:02:00 +00:00

8488 lines
195 KiB
C
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/*#define CHASE_CHAIN*/
/*
* Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* $FreeBSD$
*/
#ifndef lint
static const char rcsid[] _U_ =
"@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.309 2008-12-23 20:13:29 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifdef WIN32
#include <pcap-stdinc.h>
#else /* WIN32 */
#if HAVE_INTTYPES_H
#include <inttypes.h>
#elif HAVE_STDINT_H
#include <stdint.h>
#endif
#ifdef HAVE_SYS_BITYPES_H
#include <sys/bitypes.h>
#endif
#include <sys/types.h>
#include <sys/socket.h>
#endif /* WIN32 */
/*
* XXX - why was this included even on UNIX?
*/
#ifdef __MINGW32__
#include "ip6_misc.h"
#endif
#ifndef WIN32
#ifdef __NetBSD__
#include <sys/param.h>
#endif
#include <netinet/in.h>
#include <arpa/inet.h>
#endif /* WIN32 */
#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include <setjmp.h>
#include <stdarg.h>
#ifdef MSDOS
#include "pcap-dos.h"
#endif
#include "pcap-int.h"
#include "ethertype.h"
#include "nlpid.h"
#include "llc.h"
#include "gencode.h"
#include "ieee80211.h"
#include "atmuni31.h"
#include "sunatmpos.h"
#include "ppp.h"
#include "pcap/sll.h"
#include "pcap/ipnet.h"
#include "arcnet.h"
#if defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
#include <linux/types.h>
#include <linux/if_packet.h>
#include <linux/filter.h>
#endif
#ifdef HAVE_NET_PFVAR_H
#include <sys/socket.h>
#include <net/if.h>
#include <net/pfvar.h>
#include <net/if_pflog.h>
#endif
#ifndef offsetof
#define offsetof(s, e) ((size_t)&((s *)0)->e)
#endif
#ifdef INET6
#ifndef WIN32
#include <netdb.h> /* for "struct addrinfo" */
#endif /* WIN32 */
#endif /*INET6*/
#include <pcap/namedb.h>
#define ETHERMTU 1500
#ifndef IPPROTO_HOPOPTS
#define IPPROTO_HOPOPTS 0
#endif
#ifndef IPPROTO_ROUTING
#define IPPROTO_ROUTING 43
#endif
#ifndef IPPROTO_FRAGMENT
#define IPPROTO_FRAGMENT 44
#endif
#ifndef IPPROTO_DSTOPTS
#define IPPROTO_DSTOPTS 60
#endif
#ifndef IPPROTO_SCTP
#define IPPROTO_SCTP 132
#endif
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
#define JMP(c) ((c)|BPF_JMP|BPF_K)
/* Locals */
static jmp_buf top_ctx;
static pcap_t *bpf_pcap;
/* Hack for updating VLAN, MPLS, and PPPoE offsets. */
#ifdef WIN32
static u_int orig_linktype = (u_int)-1, orig_nl = (u_int)-1, label_stack_depth = (u_int)-1;
#else
static u_int orig_linktype = -1U, orig_nl = -1U, label_stack_depth = -1U;
#endif
/* XXX */
#ifdef PCAP_FDDIPAD
static int pcap_fddipad;
#endif
/* VARARGS */
void
bpf_error(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
if (bpf_pcap != NULL)
(void)vsnprintf(pcap_geterr(bpf_pcap), PCAP_ERRBUF_SIZE,
fmt, ap);
va_end(ap);
longjmp(top_ctx, 1);
/* NOTREACHED */
}
static void init_linktype(pcap_t *);
static void init_regs(void);
static int alloc_reg(void);
static void free_reg(int);
static struct block *root;
/*
* Value passed to gen_load_a() to indicate what the offset argument
* is relative to.
*/
enum e_offrel {
OR_PACKET, /* relative to the beginning of the packet */
OR_LINK, /* relative to the beginning of the link-layer header */
OR_MACPL, /* relative to the end of the MAC-layer header */
OR_NET, /* relative to the network-layer header */
OR_NET_NOSNAP, /* relative to the network-layer header, with no SNAP header at the link layer */
OR_TRAN_IPV4, /* relative to the transport-layer header, with IPv4 network layer */
OR_TRAN_IPV6 /* relative to the transport-layer header, with IPv6 network layer */
};
#ifdef INET6
/*
* As errors are handled by a longjmp, anything allocated must be freed
* in the longjmp handler, so it must be reachable from that handler.
* One thing that's allocated is the result of pcap_nametoaddrinfo();
* it must be freed with freeaddrinfo(). This variable points to any
* addrinfo structure that would need to be freed.
*/
static struct addrinfo *ai;
#endif
/*
* We divy out chunks of memory rather than call malloc each time so
* we don't have to worry about leaking memory. It's probably
* not a big deal if all this memory was wasted but if this ever
* goes into a library that would probably not be a good idea.
*
* XXX - this *is* in a library....
*/
#define NCHUNKS 16
#define CHUNK0SIZE 1024
struct chunk {
u_int n_left;
void *m;
};
static struct chunk chunks[NCHUNKS];
static int cur_chunk;
static void *newchunk(u_int);
static void freechunks(void);
static inline struct block *new_block(int);
static inline struct slist *new_stmt(int);
static struct block *gen_retblk(int);
static inline void syntax(void);
static void backpatch(struct block *, struct block *);
static void merge(struct block *, struct block *);
static struct block *gen_cmp(enum e_offrel, u_int, u_int, bpf_int32);
static struct block *gen_cmp_gt(enum e_offrel, u_int, u_int, bpf_int32);
static struct block *gen_cmp_ge(enum e_offrel, u_int, u_int, bpf_int32);
static struct block *gen_cmp_lt(enum e_offrel, u_int, u_int, bpf_int32);
static struct block *gen_cmp_le(enum e_offrel, u_int, u_int, bpf_int32);
static struct block *gen_mcmp(enum e_offrel, u_int, u_int, bpf_int32,
bpf_u_int32);
static struct block *gen_bcmp(enum e_offrel, u_int, u_int, const u_char *);
static struct block *gen_ncmp(enum e_offrel, bpf_u_int32, bpf_u_int32,
bpf_u_int32, bpf_u_int32, int, bpf_int32);
static struct slist *gen_load_llrel(u_int, u_int);
static struct slist *gen_load_macplrel(u_int, u_int);
static struct slist *gen_load_a(enum e_offrel, u_int, u_int);
static struct slist *gen_loadx_iphdrlen(void);
static struct block *gen_uncond(int);
static inline struct block *gen_true(void);
static inline struct block *gen_false(void);
static struct block *gen_ether_linktype(int);
static struct block *gen_ipnet_linktype(int);
static struct block *gen_linux_sll_linktype(int);
static struct slist *gen_load_prism_llprefixlen(void);
static struct slist *gen_load_avs_llprefixlen(void);
static struct slist *gen_load_radiotap_llprefixlen(void);
static struct slist *gen_load_ppi_llprefixlen(void);
static void insert_compute_vloffsets(struct block *);
static struct slist *gen_llprefixlen(void);
static struct slist *gen_off_macpl(void);
static int ethertype_to_ppptype(int);
static struct block *gen_linktype(int);
static struct block *gen_snap(bpf_u_int32, bpf_u_int32);
static struct block *gen_llc_linktype(int);
static struct block *gen_hostop(bpf_u_int32, bpf_u_int32, int, int, u_int, u_int);
#ifdef INET6
static struct block *gen_hostop6(struct in6_addr *, struct in6_addr *, int, int, u_int, u_int);
#endif
static struct block *gen_ahostop(const u_char *, int);
static struct block *gen_ehostop(const u_char *, int);
static struct block *gen_fhostop(const u_char *, int);
static struct block *gen_thostop(const u_char *, int);
static struct block *gen_wlanhostop(const u_char *, int);
static struct block *gen_ipfchostop(const u_char *, int);
static struct block *gen_dnhostop(bpf_u_int32, int);
static struct block *gen_mpls_linktype(int);
static struct block *gen_host(bpf_u_int32, bpf_u_int32, int, int, int);
#ifdef INET6
static struct block *gen_host6(struct in6_addr *, struct in6_addr *, int, int, int);
#endif
#ifndef INET6
static struct block *gen_gateway(const u_char *, bpf_u_int32 **, int, int);
#endif
static struct block *gen_ipfrag(void);
static struct block *gen_portatom(int, bpf_int32);
static struct block *gen_portrangeatom(int, bpf_int32, bpf_int32);
static struct block *gen_portatom6(int, bpf_int32);
static struct block *gen_portrangeatom6(int, bpf_int32, bpf_int32);
struct block *gen_portop(int, int, int);
static struct block *gen_port(int, int, int);
struct block *gen_portrangeop(int, int, int, int);
static struct block *gen_portrange(int, int, int, int);
struct block *gen_portop6(int, int, int);
static struct block *gen_port6(int, int, int);
struct block *gen_portrangeop6(int, int, int, int);
static struct block *gen_portrange6(int, int, int, int);
static int lookup_proto(const char *, int);
static struct block *gen_protochain(int, int, int);
static struct block *gen_proto(int, int, int);
static struct slist *xfer_to_x(struct arth *);
static struct slist *xfer_to_a(struct arth *);
static struct block *gen_mac_multicast(int);
static struct block *gen_len(int, int);
static struct block *gen_check_802_11_data_frame(void);
static struct block *gen_ppi_dlt_check(void);
static struct block *gen_msg_abbrev(int type);
static void *
newchunk(n)
u_int n;
{
struct chunk *cp;
int k;
size_t size;
#ifndef __NetBSD__
/* XXX Round up to nearest long. */
n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1);
#else
/* XXX Round up to structure boundary. */
n = ALIGN(n);
#endif
cp = &chunks[cur_chunk];
if (n > cp->n_left) {
++cp, k = ++cur_chunk;
if (k >= NCHUNKS)
bpf_error("out of memory");
size = CHUNK0SIZE << k;
cp->m = (void *)malloc(size);
if (cp->m == NULL)
bpf_error("out of memory");
memset((char *)cp->m, 0, size);
cp->n_left = size;
if (n > size)
bpf_error("out of memory");
}
cp->n_left -= n;
return (void *)((char *)cp->m + cp->n_left);
}
static void
freechunks()
{
int i;
cur_chunk = 0;
for (i = 0; i < NCHUNKS; ++i)
if (chunks[i].m != NULL) {
free(chunks[i].m);
chunks[i].m = NULL;
}
}
/*
* A strdup whose allocations are freed after code generation is over.
*/
char *
sdup(s)
register const char *s;
{
int n = strlen(s) + 1;
char *cp = newchunk(n);
strlcpy(cp, s, n);
return (cp);
}
static inline struct block *
new_block(code)
int code;
{
struct block *p;
p = (struct block *)newchunk(sizeof(*p));
p->s.code = code;
p->head = p;
return p;
}
static inline struct slist *
new_stmt(code)
int code;
{
struct slist *p;
p = (struct slist *)newchunk(sizeof(*p));
p->s.code = code;
return p;
}
static struct block *
gen_retblk(v)
int v;
{
struct block *b = new_block(BPF_RET|BPF_K);
b->s.k = v;
return b;
}
static inline void
syntax()
{
bpf_error("syntax error in filter expression");
}
static bpf_u_int32 netmask;
static int snaplen;
int no_optimize;
#ifdef WIN32
static int
pcap_compile_unsafe(pcap_t *p, struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask);
int
pcap_compile(pcap_t *p, struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask)
{
int result;
EnterCriticalSection(&g_PcapCompileCriticalSection);
result = pcap_compile_unsafe(p, program, buf, optimize, mask);
LeaveCriticalSection(&g_PcapCompileCriticalSection);
return result;
}
static int
pcap_compile_unsafe(pcap_t *p, struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask)
#else /* WIN32 */
int
pcap_compile(pcap_t *p, struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask)
#endif /* WIN32 */
{
extern int n_errors;
const char * volatile xbuf = buf;
u_int len;
/*
* If this pcap_t hasn't been activated, it doesn't have a
* link-layer type, so we can't use it.
*/
if (!p->activated) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"not-yet-activated pcap_t passed to pcap_compile");
return (-1);
}
no_optimize = 0;
n_errors = 0;
root = NULL;
bpf_pcap = p;
init_regs();
if (setjmp(top_ctx)) {
#ifdef INET6
if (ai != NULL) {
freeaddrinfo(ai);
ai = NULL;
}
#endif
lex_cleanup();
freechunks();
return (-1);
}
netmask = mask;
snaplen = pcap_snapshot(p);
if (snaplen == 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"snaplen of 0 rejects all packets");
return -1;
}
lex_init(xbuf ? xbuf : "");
init_linktype(p);
(void)pcap_parse();
if (n_errors)
syntax();
if (root == NULL)
root = gen_retblk(snaplen);
if (optimize && !no_optimize) {
bpf_optimize(&root);
if (root == NULL ||
(root->s.code == (BPF_RET|BPF_K) && root->s.k == 0))
bpf_error("expression rejects all packets");
}
program->bf_insns = icode_to_fcode(root, &len);
program->bf_len = len;
lex_cleanup();
freechunks();
return (0);
}
/*
* entry point for using the compiler with no pcap open
* pass in all the stuff that is needed explicitly instead.
*/
int
pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask)
{
pcap_t *p;
int ret;
p = pcap_open_dead(linktype_arg, snaplen_arg);
if (p == NULL)
return (-1);
ret = pcap_compile(p, program, buf, optimize, mask);
pcap_close(p);
return (ret);
}
/*
* Clean up a "struct bpf_program" by freeing all the memory allocated
* in it.
*/
void
pcap_freecode(struct bpf_program *program)
{
program->bf_len = 0;
if (program->bf_insns != NULL) {
free((char *)program->bf_insns);
program->bf_insns = NULL;
}
}
/*
* Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
* which of the jt and jf fields has been resolved and which is a pointer
* back to another unresolved block (or nil). At least one of the fields
* in each block is already resolved.
*/
static void
backpatch(list, target)
struct block *list, *target;
{
struct block *next;
while (list) {
if (!list->sense) {
next = JT(list);
JT(list) = target;
} else {
next = JF(list);
JF(list) = target;
}
list = next;
}
}
/*
* Merge the lists in b0 and b1, using the 'sense' field to indicate
* which of jt and jf is the link.
*/
static void
merge(b0, b1)
struct block *b0, *b1;
{
register struct block **p = &b0;
/* Find end of list. */
while (*p)
p = !((*p)->sense) ? &JT(*p) : &JF(*p);
/* Concatenate the lists. */
*p = b1;
}
void
finish_parse(p)
struct block *p;
{
struct block *ppi_dlt_check;
/*
* Insert before the statements of the first (root) block any
* statements needed to load the lengths of any variable-length
* headers into registers.
*
* XXX - a fancier strategy would be to insert those before the
* statements of all blocks that use those lengths and that
* have no predecessors that use them, so that we only compute
* the lengths if we need them. There might be even better
* approaches than that.
*
* However, those strategies would be more complicated, and
* as we don't generate code to compute a length if the
* program has no tests that use the length, and as most
* tests will probably use those lengths, we would just
* postpone computing the lengths so that it's not done
* for tests that fail early, and it's not clear that's
* worth the effort.
*/
insert_compute_vloffsets(p->head);
/*
* For DLT_PPI captures, generate a check of the per-packet
* DLT value to make sure it's DLT_IEEE802_11.
*/
ppi_dlt_check = gen_ppi_dlt_check();
if (ppi_dlt_check != NULL)
gen_and(ppi_dlt_check, p);
backpatch(p, gen_retblk(snaplen));
p->sense = !p->sense;
backpatch(p, gen_retblk(0));
root = p->head;
}
void
gen_and(b0, b1)
struct block *b0, *b1;
{
backpatch(b0, b1->head);
b0->sense = !b0->sense;
b1->sense = !b1->sense;
merge(b1, b0);
b1->sense = !b1->sense;
b1->head = b0->head;
}
void
gen_or(b0, b1)
struct block *b0, *b1;
{
b0->sense = !b0->sense;
backpatch(b0, b1->head);
b0->sense = !b0->sense;
merge(b1, b0);
b1->head = b0->head;
}
void
gen_not(b)
struct block *b;
{
b->sense = !b->sense;
}
static struct block *
gen_cmp(offrel, offset, size, v)
enum e_offrel offrel;
u_int offset, size;
bpf_int32 v;
{
return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v);
}
static struct block *
gen_cmp_gt(offrel, offset, size, v)
enum e_offrel offrel;
u_int offset, size;
bpf_int32 v;
{
return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGT, 0, v);
}
static struct block *
gen_cmp_ge(offrel, offset, size, v)
enum e_offrel offrel;
u_int offset, size;
bpf_int32 v;
{
return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGE, 0, v);
}
static struct block *
gen_cmp_lt(offrel, offset, size, v)
enum e_offrel offrel;
u_int offset, size;
bpf_int32 v;
{
return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGE, 1, v);
}
static struct block *
gen_cmp_le(offrel, offset, size, v)
enum e_offrel offrel;
u_int offset, size;
bpf_int32 v;
{
return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGT, 1, v);
}
static struct block *
gen_mcmp(offrel, offset, size, v, mask)
enum e_offrel offrel;
u_int offset, size;
bpf_int32 v;
bpf_u_int32 mask;
{
return gen_ncmp(offrel, offset, size, mask, BPF_JEQ, 0, v);
}
static struct block *
gen_bcmp(offrel, offset, size, v)
enum e_offrel offrel;
register u_int offset, size;
register const u_char *v;
{
register struct block *b, *tmp;
b = NULL;
while (size >= 4) {
register const u_char *p = &v[size - 4];
bpf_int32 w = ((bpf_int32)p[0] << 24) |
((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3];
tmp = gen_cmp(offrel, offset + size - 4, BPF_W, w);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
size -= 4;
}
while (size >= 2) {
register const u_char *p = &v[size - 2];
bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1];
tmp = gen_cmp(offrel, offset + size - 2, BPF_H, w);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
size -= 2;
}
if (size > 0) {
tmp = gen_cmp(offrel, offset, BPF_B, (bpf_int32)v[0]);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
}
return b;
}
/*
* AND the field of size "size" at offset "offset" relative to the header
* specified by "offrel" with "mask", and compare it with the value "v"
* with the test specified by "jtype"; if "reverse" is true, the test
* should test the opposite of "jtype".
*/
static struct block *
gen_ncmp(offrel, offset, size, mask, jtype, reverse, v)
enum e_offrel offrel;
bpf_int32 v;
bpf_u_int32 offset, size, mask, jtype;
int reverse;
{
struct slist *s, *s2;
struct block *b;
s = gen_load_a(offrel, offset, size);
if (mask != 0xffffffff) {
s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K);
s2->s.k = mask;
sappend(s, s2);
}
b = new_block(JMP(jtype));
b->stmts = s;
b->s.k = v;
if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE))
gen_not(b);
return b;
}
/*
* Various code constructs need to know the layout of the data link
* layer. These variables give the necessary offsets from the beginning
* of the packet data.
*/
/*
* This is the offset of the beginning of the link-layer header from
* the beginning of the raw packet data.
*
* It's usually 0, except for 802.11 with a fixed-length radio header.
* (For 802.11 with a variable-length radio header, we have to generate
* code to compute that offset; off_ll is 0 in that case.)
*/
static u_int off_ll;
/*
* If there's a variable-length header preceding the link-layer header,
* "reg_off_ll" is the register number for a register containing the
* length of that header, and therefore the offset of the link-layer
* header from the beginning of the raw packet data. Otherwise,
* "reg_off_ll" is -1.
*/
static int reg_off_ll;
/*
* This is the offset of the beginning of the MAC-layer header from
* the beginning of the link-layer header.
* It's usually 0, except for ATM LANE, where it's the offset, relative
* to the beginning of the raw packet data, of the Ethernet header, and
* for Ethernet with various additional information.
*/
static u_int off_mac;
/*
* This is the offset of the beginning of the MAC-layer payload,
* from the beginning of the raw packet data.
*
* I.e., it's the sum of the length of the link-layer header (without,
* for example, any 802.2 LLC header, so it's the MAC-layer
* portion of that header), plus any prefix preceding the
* link-layer header.
*/
static u_int off_macpl;
/*
* This is 1 if the offset of the beginning of the MAC-layer payload
* from the beginning of the link-layer header is variable-length.
*/
static int off_macpl_is_variable;
/*
* If the link layer has variable_length headers, "reg_off_macpl"
* is the register number for a register containing the length of the
* link-layer header plus the length of any variable-length header
* preceding the link-layer header. Otherwise, "reg_off_macpl"
* is -1.
*/
static int reg_off_macpl;
/*
* "off_linktype" is the offset to information in the link-layer header
* giving the packet type. This offset is relative to the beginning
* of the link-layer header (i.e., it doesn't include off_ll).
*
* For Ethernet, it's the offset of the Ethernet type field.
*
* For link-layer types that always use 802.2 headers, it's the
* offset of the LLC header.
*
* For PPP, it's the offset of the PPP type field.
*
* For Cisco HDLC, it's the offset of the CHDLC type field.
*
* For BSD loopback, it's the offset of the AF_ value.
*
* For Linux cooked sockets, it's the offset of the type field.
*
* It's set to -1 for no encapsulation, in which case, IP is assumed.
*/
static u_int off_linktype;
/*
* TRUE if "pppoes" appeared in the filter; it causes link-layer type
* checks to check the PPP header, assumed to follow a LAN-style link-
* layer header and a PPPoE session header.
*/
static int is_pppoes = 0;
/*
* TRUE if the link layer includes an ATM pseudo-header.
*/
static int is_atm = 0;
/*
* TRUE if "lane" appeared in the filter; it causes us to generate
* code that assumes LANE rather than LLC-encapsulated traffic in SunATM.
*/
static int is_lane = 0;
/*
* These are offsets for the ATM pseudo-header.
*/
static u_int off_vpi;
static u_int off_vci;
static u_int off_proto;
/*
* These are offsets for the MTP2 fields.
*/
static u_int off_li;
/*
* These are offsets for the MTP3 fields.
*/
static u_int off_sio;
static u_int off_opc;
static u_int off_dpc;
static u_int off_sls;
/*
* This is the offset of the first byte after the ATM pseudo_header,
* or -1 if there is no ATM pseudo-header.
*/
static u_int off_payload;
/*
* These are offsets to the beginning of the network-layer header.
* They are relative to the beginning of the MAC-layer payload (i.e.,
* they don't include off_ll or off_macpl).
*
* If the link layer never uses 802.2 LLC:
*
* "off_nl" and "off_nl_nosnap" are the same.
*
* If the link layer always uses 802.2 LLC:
*
* "off_nl" is the offset if there's a SNAP header following
* the 802.2 header;
*
* "off_nl_nosnap" is the offset if there's no SNAP header.
*
* If the link layer is Ethernet:
*
* "off_nl" is the offset if the packet is an Ethernet II packet
* (we assume no 802.3+802.2+SNAP);
*
* "off_nl_nosnap" is the offset if the packet is an 802.3 packet
* with an 802.2 header following it.
*/
static u_int off_nl;
static u_int off_nl_nosnap;
static int linktype;
static void
init_linktype(p)
pcap_t *p;
{
linktype = pcap_datalink(p);
#ifdef PCAP_FDDIPAD
pcap_fddipad = p->fddipad;
#endif
/*
* Assume it's not raw ATM with a pseudo-header, for now.
*/
off_mac = 0;
is_atm = 0;
is_lane = 0;
off_vpi = -1;
off_vci = -1;
off_proto = -1;
off_payload = -1;
/*
* And that we're not doing PPPoE.
*/
is_pppoes = 0;
/*
* And assume we're not doing SS7.
*/
off_li = -1;
off_sio = -1;
off_opc = -1;
off_dpc = -1;
off_sls = -1;
/*
* Also assume it's not 802.11.
*/
off_ll = 0;
off_macpl = 0;
off_macpl_is_variable = 0;
orig_linktype = -1;
orig_nl = -1;
label_stack_depth = 0;
reg_off_ll = -1;
reg_off_macpl = -1;
switch (linktype) {
case DLT_ARCNET:
off_linktype = 2;
off_macpl = 6;
off_nl = 0; /* XXX in reality, variable! */
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_ARCNET_LINUX:
off_linktype = 4;
off_macpl = 8;
off_nl = 0; /* XXX in reality, variable! */
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_EN10MB:
off_linktype = 12;
off_macpl = 14; /* Ethernet header length */
off_nl = 0; /* Ethernet II */
off_nl_nosnap = 3; /* 802.3+802.2 */
return;
case DLT_SLIP:
/*
* SLIP doesn't have a link level type. The 16 byte
* header is hacked into our SLIP driver.
*/
off_linktype = -1;
off_macpl = 16;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_SLIP_BSDOS:
/* XXX this may be the same as the DLT_PPP_BSDOS case */
off_linktype = -1;
/* XXX end */
off_macpl = 24;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_NULL:
case DLT_LOOP:
off_linktype = 0;
off_macpl = 4;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_ENC:
off_linktype = 0;
off_macpl = 12;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_PPP:
case DLT_PPP_PPPD:
case DLT_C_HDLC: /* BSD/OS Cisco HDLC */
case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */
off_linktype = 2;
off_macpl = 4;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_PPP_ETHER:
/*
* This does no include the Ethernet header, and
* only covers session state.
*/
off_linktype = 6;
off_macpl = 8;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_PPP_BSDOS:
off_linktype = 5;
off_macpl = 24;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_FDDI:
/*
* FDDI doesn't really have a link-level type field.
* We set "off_linktype" to the offset of the LLC header.
*
* To check for Ethernet types, we assume that SSAP = SNAP
* is being used and pick out the encapsulated Ethernet type.
* XXX - should we generate code to check for SNAP?
*/
off_linktype = 13;
#ifdef PCAP_FDDIPAD
off_linktype += pcap_fddipad;
#endif
off_macpl = 13; /* FDDI MAC header length */
#ifdef PCAP_FDDIPAD
off_macpl += pcap_fddipad;
#endif
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
case DLT_IEEE802:
/*
* Token Ring doesn't really have a link-level type field.
* We set "off_linktype" to the offset of the LLC header.
*
* To check for Ethernet types, we assume that SSAP = SNAP
* is being used and pick out the encapsulated Ethernet type.
* XXX - should we generate code to check for SNAP?
*
* XXX - the header is actually variable-length.
* Some various Linux patched versions gave 38
* as "off_linktype" and 40 as "off_nl"; however,
* if a token ring packet has *no* routing
* information, i.e. is not source-routed, the correct
* values are 20 and 22, as they are in the vanilla code.
*
* A packet is source-routed iff the uppermost bit
* of the first byte of the source address, at an
* offset of 8, has the uppermost bit set. If the
* packet is source-routed, the total number of bytes
* of routing information is 2 plus bits 0x1F00 of
* the 16-bit value at an offset of 14 (shifted right
* 8 - figure out which byte that is).
*/
off_linktype = 14;
off_macpl = 14; /* Token Ring MAC header length */
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
/*
* 802.11 doesn't really have a link-level type field.
* We set "off_linktype" to the offset of the LLC header.
*
* To check for Ethernet types, we assume that SSAP = SNAP
* is being used and pick out the encapsulated Ethernet type.
* XXX - should we generate code to check for SNAP?
*
* We also handle variable-length radio headers here.
* The Prism header is in theory variable-length, but in
* practice it's always 144 bytes long. However, some
* drivers on Linux use ARPHRD_IEEE80211_PRISM, but
* sometimes or always supply an AVS header, so we
* have to check whether the radio header is a Prism
* header or an AVS header, so, in practice, it's
* variable-length.
*/
off_linktype = 24;
off_macpl = 0; /* link-layer header is variable-length */
off_macpl_is_variable = 1;
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
case DLT_PPI:
/*
* At the moment we treat PPI the same way that we treat
* normal Radiotap encoded packets. The difference is in
* the function that generates the code at the beginning
* to compute the header length. Since this code generator
* of PPI supports bare 802.11 encapsulation only (i.e.
* the encapsulated DLT should be DLT_IEEE802_11) we
* generate code to check for this too.
*/
off_linktype = 24;
off_macpl = 0; /* link-layer header is variable-length */
off_macpl_is_variable = 1;
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
case DLT_ATM_RFC1483:
case DLT_ATM_CLIP: /* Linux ATM defines this */
/*
* assume routed, non-ISO PDUs
* (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00)
*
* XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS,
* or PPP with the PPP NLPID (e.g., PPPoA)? The
* latter would presumably be treated the way PPPoE
* should be, so you can do "pppoe and udp port 2049"
* or "pppoa and tcp port 80" and have it check for
* PPPo{A,E} and a PPP protocol of IP and....
*/
off_linktype = 0;
off_macpl = 0; /* packet begins with LLC header */
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
case DLT_SUNATM:
/*
* Full Frontal ATM; you get AALn PDUs with an ATM
* pseudo-header.
*/
is_atm = 1;
off_vpi = SUNATM_VPI_POS;
off_vci = SUNATM_VCI_POS;
off_proto = PROTO_POS;
off_mac = -1; /* assume LLC-encapsulated, so no MAC-layer header */
off_payload = SUNATM_PKT_BEGIN_POS;
off_linktype = off_payload;
off_macpl = off_payload; /* if LLC-encapsulated */
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
case DLT_RAW:
case DLT_IPV4:
case DLT_IPV6:
off_linktype = -1;
off_macpl = 0;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_LINUX_SLL: /* fake header for Linux cooked socket */
off_linktype = 14;
off_macpl = 16;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_LTALK:
/*
* LocalTalk does have a 1-byte type field in the LLAP header,
* but really it just indicates whether there is a "short" or
* "long" DDP packet following.
*/
off_linktype = -1;
off_macpl = 0;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_IP_OVER_FC:
/*
* RFC 2625 IP-over-Fibre-Channel doesn't really have a
* link-level type field. We set "off_linktype" to the
* offset of the LLC header.
*
* To check for Ethernet types, we assume that SSAP = SNAP
* is being used and pick out the encapsulated Ethernet type.
* XXX - should we generate code to check for SNAP? RFC
* 2625 says SNAP should be used.
*/
off_linktype = 16;
off_macpl = 16;
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
case DLT_FRELAY:
/*
* XXX - we should set this to handle SNAP-encapsulated
* frames (NLPID of 0x80).
*/
off_linktype = -1;
off_macpl = 0;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
/*
* the only BPF-interesting FRF.16 frames are non-control frames;
* Frame Relay has a variable length link-layer
* so lets start with offset 4 for now and increments later on (FIXME);
*/
case DLT_MFR:
off_linktype = -1;
off_macpl = 0;
off_nl = 4;
off_nl_nosnap = 0; /* XXX - for now -> no 802.2 LLC */
return;
case DLT_APPLE_IP_OVER_IEEE1394:
off_linktype = 16;
off_macpl = 18;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_SYMANTEC_FIREWALL:
off_linktype = 6;
off_macpl = 44;
off_nl = 0; /* Ethernet II */
off_nl_nosnap = 0; /* XXX - what does it do with 802.3 packets? */
return;
#ifdef HAVE_NET_PFVAR_H
case DLT_PFLOG:
off_linktype = 0;
off_macpl = PFLOG_HDRLEN;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
#endif
case DLT_JUNIPER_MFR:
case DLT_JUNIPER_MLFR:
case DLT_JUNIPER_MLPPP:
case DLT_JUNIPER_PPP:
case DLT_JUNIPER_CHDLC:
case DLT_JUNIPER_FRELAY:
off_linktype = 4;
off_macpl = 4;
off_nl = 0;
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_ATM1:
off_linktype = 4; /* in reality variable between 4-8 */
off_macpl = 4; /* in reality variable between 4-8 */
off_nl = 0;
off_nl_nosnap = 10;
return;
case DLT_JUNIPER_ATM2:
off_linktype = 8; /* in reality variable between 8-12 */
off_macpl = 8; /* in reality variable between 8-12 */
off_nl = 0;
off_nl_nosnap = 10;
return;
/* frames captured on a Juniper PPPoE service PIC
* contain raw ethernet frames */
case DLT_JUNIPER_PPPOE:
case DLT_JUNIPER_ETHER:
off_macpl = 14;
off_linktype = 16;
off_nl = 18; /* Ethernet II */
off_nl_nosnap = 21; /* 802.3+802.2 */
return;
case DLT_JUNIPER_PPPOE_ATM:
off_linktype = 4;
off_macpl = 6;
off_nl = 0;
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_GGSN:
off_linktype = 6;
off_macpl = 12;
off_nl = 0;
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_ES:
off_linktype = 6;
off_macpl = -1; /* not really a network layer but raw IP addresses */
off_nl = -1; /* not really a network layer but raw IP addresses */
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_MONITOR:
off_linktype = 12;
off_macpl = 12;
off_nl = 0; /* raw IP/IP6 header */
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_SERVICES:
off_linktype = 12;
off_macpl = -1; /* L3 proto location dep. on cookie type */
off_nl = -1; /* L3 proto location dep. on cookie type */
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_VP:
off_linktype = 18;
off_macpl = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_JUNIPER_ST:
off_linktype = 18;
off_macpl = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_JUNIPER_ISM:
off_linktype = 8;
off_macpl = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_JUNIPER_VS:
case DLT_JUNIPER_SRX_E2E:
case DLT_JUNIPER_FIBRECHANNEL:
case DLT_JUNIPER_ATM_CEMIC:
off_linktype = 8;
off_macpl = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_MTP2:
off_li = 2;
off_sio = 3;
off_opc = 4;
off_dpc = 4;
off_sls = 7;
off_linktype = -1;
off_macpl = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_MTP2_WITH_PHDR:
off_li = 6;
off_sio = 7;
off_opc = 8;
off_dpc = 8;
off_sls = 11;
off_linktype = -1;
off_macpl = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_ERF:
off_li = 22;
off_sio = 23;
off_opc = 24;
off_dpc = 24;
off_sls = 27;
off_linktype = -1;
off_macpl = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_PFSYNC:
off_linktype = -1;
off_macpl = 4;
off_nl = 0;
off_nl_nosnap = 0;
return;
case DLT_AX25_KISS:
/*
* Currently, only raw "link[N:M]" filtering is supported.
*/
off_linktype = -1; /* variable, min 15, max 71 steps of 7 */
off_macpl = -1;
off_nl = -1; /* variable, min 16, max 71 steps of 7 */
off_nl_nosnap = -1; /* no 802.2 LLC */
off_mac = 1; /* step over the kiss length byte */
return;
case DLT_IPNET:
off_linktype = 1;
off_macpl = 24; /* ipnet header length */
off_nl = 0;
off_nl_nosnap = -1;
return;
case DLT_NETANALYZER:
off_mac = 4; /* MAC header is past 4-byte pseudo-header */
off_linktype = 16; /* includes 4-byte pseudo-header */
off_macpl = 18; /* pseudo-header+Ethernet header length */
off_nl = 0; /* Ethernet II */
off_nl_nosnap = 3; /* 802.3+802.2 */
return;
case DLT_NETANALYZER_TRANSPARENT:
off_mac = 12; /* MAC header is past 4-byte pseudo-header, preamble, and SFD */
off_linktype = 24; /* includes 4-byte pseudo-header+preamble+SFD */
off_macpl = 26; /* pseudo-header+preamble+SFD+Ethernet header length */
off_nl = 0; /* Ethernet II */
off_nl_nosnap = 3; /* 802.3+802.2 */
return;
default:
/*
* For values in the range in which we've assigned new
* DLT_ values, only raw "link[N:M]" filtering is supported.
*/
if (linktype >= DLT_MATCHING_MIN &&
linktype <= DLT_MATCHING_MAX) {
off_linktype = -1;
off_macpl = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
}
}
bpf_error("unknown data link type %d", linktype);
/* NOTREACHED */
}
/*
* Load a value relative to the beginning of the link-layer header.
* The link-layer header doesn't necessarily begin at the beginning
* of the packet data; there might be a variable-length prefix containing
* radio information.
*/
static struct slist *
gen_load_llrel(offset, size)
u_int offset, size;
{
struct slist *s, *s2;
s = gen_llprefixlen();
/*
* If "s" is non-null, it has code to arrange that the X register
* contains the length of the prefix preceding the link-layer
* header.
*
* Otherwise, the length of the prefix preceding the link-layer
* header is "off_ll".
*/
if (s != NULL) {
/*
* There's a variable-length prefix preceding the
* link-layer header. "s" points to a list of statements
* that put the length of that prefix into the X register.
* do an indirect load, to use the X register as an offset.
*/
s2 = new_stmt(BPF_LD|BPF_IND|size);
s2->s.k = offset;
sappend(s, s2);
} else {
/*
* There is no variable-length header preceding the
* link-layer header; add in off_ll, which, if there's
* a fixed-length header preceding the link-layer header,
* is the length of that header.
*/
s = new_stmt(BPF_LD|BPF_ABS|size);
s->s.k = offset + off_ll;
}
return s;
}
/*
* Load a value relative to the beginning of the MAC-layer payload.
*/
static struct slist *
gen_load_macplrel(offset, size)
u_int offset, size;
{
struct slist *s, *s2;
s = gen_off_macpl();
/*
* If s is non-null, the offset of the MAC-layer payload is
* variable, and s points to a list of instructions that
* arrange that the X register contains that offset.
*
* Otherwise, the offset of the MAC-layer payload is constant,
* and is in off_macpl.
*/
if (s != NULL) {
/*
* The offset of the MAC-layer payload is in the X
* register. Do an indirect load, to use the X register
* as an offset.
*/
s2 = new_stmt(BPF_LD|BPF_IND|size);
s2->s.k = offset;
sappend(s, s2);
} else {
/*
* The offset of the MAC-layer payload is constant,
* and is in off_macpl; load the value at that offset
* plus the specified offset.
*/
s = new_stmt(BPF_LD|BPF_ABS|size);
s->s.k = off_macpl + offset;
}
return s;
}
/*
* Load a value relative to the beginning of the specified header.
*/
static struct slist *
gen_load_a(offrel, offset, size)
enum e_offrel offrel;
u_int offset, size;
{
struct slist *s, *s2;
switch (offrel) {
case OR_PACKET:
s = new_stmt(BPF_LD|BPF_ABS|size);
s->s.k = offset;
break;
case OR_LINK:
s = gen_load_llrel(offset, size);
break;
case OR_MACPL:
s = gen_load_macplrel(offset, size);
break;
case OR_NET:
s = gen_load_macplrel(off_nl + offset, size);
break;
case OR_NET_NOSNAP:
s = gen_load_macplrel(off_nl_nosnap + offset, size);
break;
case OR_TRAN_IPV4:
/*
* Load the X register with the length of the IPv4 header
* (plus the offset of the link-layer header, if it's
* preceded by a variable-length header such as a radio
* header), in bytes.
*/
s = gen_loadx_iphdrlen();
/*
* Load the item at {offset of the MAC-layer payload} +
* {offset, relative to the start of the MAC-layer
* paylod, of the IPv4 header} + {length of the IPv4 header} +
* {specified offset}.
*
* (If the offset of the MAC-layer payload is variable,
* it's included in the value in the X register, and
* off_macpl is 0.)
*/
s2 = new_stmt(BPF_LD|BPF_IND|size);
s2->s.k = off_macpl + off_nl + offset;
sappend(s, s2);
break;
case OR_TRAN_IPV6:
s = gen_load_macplrel(off_nl + 40 + offset, size);
break;
default:
abort();
return NULL;
}
return s;
}
/*
* Generate code to load into the X register the sum of the length of
* the IPv4 header and any variable-length header preceding the link-layer
* header.
*/
static struct slist *
gen_loadx_iphdrlen()
{
struct slist *s, *s2;
s = gen_off_macpl();
if (s != NULL) {
/*
* There's a variable-length prefix preceding the
* link-layer header, or the link-layer header is itself
* variable-length. "s" points to a list of statements
* that put the offset of the MAC-layer payload into
* the X register.
*
* The 4*([k]&0xf) addressing mode can't be used, as we
* don't have a constant offset, so we have to load the
* value in question into the A register and add to it
* the value from the X register.
*/
s2 = new_stmt(BPF_LD|BPF_IND|BPF_B);
s2->s.k = off_nl;
sappend(s, s2);
s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K);
s2->s.k = 0xf;
sappend(s, s2);
s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K);
s2->s.k = 2;
sappend(s, s2);
/*
* The A register now contains the length of the
* IP header. We need to add to it the offset of
* the MAC-layer payload, which is still in the X
* register, and move the result into the X register.
*/
sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(BPF_MISC|BPF_TAX));
} else {
/*
* There is no variable-length header preceding the
* link-layer header, and the link-layer header is
* fixed-length; load the length of the IPv4 header,
* which is at an offset of off_nl from the beginning
* of the MAC-layer payload, and thus at an offset
* of off_mac_pl + off_nl from the beginning of the
* raw packet data.
*/
s = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
s->s.k = off_macpl + off_nl;
}
return s;
}
static struct block *
gen_uncond(rsense)
int rsense;
{
struct block *b;
struct slist *s;
s = new_stmt(BPF_LD|BPF_IMM);
s->s.k = !rsense;
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
return b;
}
static inline struct block *
gen_true()
{
return gen_uncond(1);
}
static inline struct block *
gen_false()
{
return gen_uncond(0);
}
/*
* Byte-swap a 32-bit number.
* ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
* big-endian platforms.)
*/
#define SWAPLONG(y) \
((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
/*
* Generate code to match a particular packet type.
*
* "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
* value, if <= ETHERMTU. We use that to determine whether to
* match the type/length field or to check the type/length field for
* a value <= ETHERMTU to see whether it's a type field and then do
* the appropriate test.
*/
static struct block *
gen_ether_linktype(proto)
register int proto;
{
struct block *b0, *b1;
switch (proto) {
case LLCSAP_ISONS:
case LLCSAP_IP:
case LLCSAP_NETBEUI:
/*
* OSI protocols and NetBEUI always use 802.2 encapsulation,
* so we check the DSAP and SSAP.
*
* LLCSAP_IP checks for IP-over-802.2, rather
* than IP-over-Ethernet or IP-over-SNAP.
*
* XXX - should we check both the DSAP and the
* SSAP, like this, or should we check just the
* DSAP, as we do for other types <= ETHERMTU
* (i.e., other SAP values)?
*/
b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
gen_not(b0);
b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32)
((proto << 8) | proto));
gen_and(b0, b1);
return b1;
case LLCSAP_IPX:
/*
* Check for;
*
* Ethernet_II frames, which are Ethernet
* frames with a frame type of ETHERTYPE_IPX;
*
* Ethernet_802.3 frames, which are 802.3
* frames (i.e., the type/length field is
* a length field, <= ETHERMTU, rather than
* a type field) with the first two bytes
* after the Ethernet/802.3 header being
* 0xFFFF;
*
* Ethernet_802.2 frames, which are 802.3
* frames with an 802.2 LLC header and
* with the IPX LSAP as the DSAP in the LLC
* header;
*
* Ethernet_SNAP frames, which are 802.3
* frames with an LLC header and a SNAP
* header and with an OUI of 0x000000
* (encapsulated Ethernet) and a protocol
* ID of ETHERTYPE_IPX in the SNAP header.
*
* XXX - should we generate the same code both
* for tests for LLCSAP_IPX and for ETHERTYPE_IPX?
*/
/*
* This generates code to check both for the
* IPX LSAP (Ethernet_802.2) and for Ethernet_802.3.
*/
b0 = gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32)0xFFFF);
gen_or(b0, b1);
/*
* Now we add code to check for SNAP frames with
* ETHERTYPE_IPX, i.e. Ethernet_SNAP.
*/
b0 = gen_snap(0x000000, ETHERTYPE_IPX);
gen_or(b0, b1);
/*
* Now we generate code to check for 802.3
* frames in general.
*/
b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
gen_not(b0);
/*
* Now add the check for 802.3 frames before the
* check for Ethernet_802.2 and Ethernet_802.3,
* as those checks should only be done on 802.3
* frames, not on Ethernet frames.
*/
gen_and(b0, b1);
/*
* Now add the check for Ethernet_II frames, and
* do that before checking for the other frame
* types.
*/
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
(bpf_int32)ETHERTYPE_IPX);
gen_or(b0, b1);
return b1;
case ETHERTYPE_ATALK:
case ETHERTYPE_AARP:
/*
* EtherTalk (AppleTalk protocols on Ethernet link
* layer) may use 802.2 encapsulation.
*/
/*
* Check for 802.2 encapsulation (EtherTalk phase 2?);
* we check for an Ethernet type field less than
* 1500, which means it's an 802.3 length field.
*/
b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
gen_not(b0);
/*
* 802.2-encapsulated ETHERTYPE_ATALK packets are
* SNAP packets with an organization code of
* 0x080007 (Apple, for Appletalk) and a protocol
* type of ETHERTYPE_ATALK (Appletalk).
*
* 802.2-encapsulated ETHERTYPE_AARP packets are
* SNAP packets with an organization code of
* 0x000000 (encapsulated Ethernet) and a protocol
* type of ETHERTYPE_AARP (Appletalk ARP).
*/
if (proto == ETHERTYPE_ATALK)
b1 = gen_snap(0x080007, ETHERTYPE_ATALK);
else /* proto == ETHERTYPE_AARP */
b1 = gen_snap(0x000000, ETHERTYPE_AARP);
gen_and(b0, b1);
/*
* Check for Ethernet encapsulation (Ethertalk
* phase 1?); we just check for the Ethernet
* protocol type.
*/
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
gen_or(b0, b1);
return b1;
default:
if (proto <= ETHERMTU) {
/*
* This is an LLC SAP value, so the frames
* that match would be 802.2 frames.
* Check that the frame is an 802.2 frame
* (i.e., that the length/type field is
* a length field, <= ETHERMTU) and
* then check the DSAP.
*/
b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU);
gen_not(b0);
b1 = gen_cmp(OR_LINK, off_linktype + 2, BPF_B,
(bpf_int32)proto);
gen_and(b0, b1);
return b1;
} else {
/*
* This is an Ethernet type, so compare
* the length/type field with it (if
* the frame is an 802.2 frame, the length
* field will be <= ETHERMTU, and, as
* "proto" is > ETHERMTU, this test
* will fail and the frame won't match,
* which is what we want).
*/
return gen_cmp(OR_LINK, off_linktype, BPF_H,
(bpf_int32)proto);
}
}
}
/*
* "proto" is an Ethernet type value and for IPNET, if it is not IPv4
* or IPv6 then we have an error.
*/
static struct block *
gen_ipnet_linktype(proto)
register int proto;
{
switch (proto) {
case ETHERTYPE_IP:
return gen_cmp(OR_LINK, off_linktype, BPF_B,
(bpf_int32)IPH_AF_INET);
/* NOTREACHED */
case ETHERTYPE_IPV6:
return gen_cmp(OR_LINK, off_linktype, BPF_B,
(bpf_int32)IPH_AF_INET6);
/* NOTREACHED */
default:
break;
}
return gen_false();
}
/*
* Generate code to match a particular packet type.
*
* "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
* value, if <= ETHERMTU. We use that to determine whether to
* match the type field or to check the type field for the special
* LINUX_SLL_P_802_2 value and then do the appropriate test.
*/
static struct block *
gen_linux_sll_linktype(proto)
register int proto;
{
struct block *b0, *b1;
switch (proto) {
case LLCSAP_ISONS:
case LLCSAP_IP:
case LLCSAP_NETBEUI:
/*
* OSI protocols and NetBEUI always use 802.2 encapsulation,
* so we check the DSAP and SSAP.
*
* LLCSAP_IP checks for IP-over-802.2, rather
* than IP-over-Ethernet or IP-over-SNAP.
*
* XXX - should we check both the DSAP and the
* SSAP, like this, or should we check just the
* DSAP, as we do for other types <= ETHERMTU
* (i.e., other SAP values)?
*/
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2);
b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32)
((proto << 8) | proto));
gen_and(b0, b1);
return b1;
case LLCSAP_IPX:
/*
* Ethernet_II frames, which are Ethernet
* frames with a frame type of ETHERTYPE_IPX;
*
* Ethernet_802.3 frames, which have a frame
* type of LINUX_SLL_P_802_3;
*
* Ethernet_802.2 frames, which are 802.3
* frames with an 802.2 LLC header (i.e, have
* a frame type of LINUX_SLL_P_802_2) and
* with the IPX LSAP as the DSAP in the LLC
* header;
*
* Ethernet_SNAP frames, which are 802.3
* frames with an LLC header and a SNAP
* header and with an OUI of 0x000000
* (encapsulated Ethernet) and a protocol
* ID of ETHERTYPE_IPX in the SNAP header.
*
* First, do the checks on LINUX_SLL_P_802_2
* frames; generate the check for either
* Ethernet_802.2 or Ethernet_SNAP frames, and
* then put a check for LINUX_SLL_P_802_2 frames
* before it.
*/
b0 = gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
b1 = gen_snap(0x000000, ETHERTYPE_IPX);
gen_or(b0, b1);
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2);
gen_and(b0, b1);
/*
* Now check for 802.3 frames and OR that with
* the previous test.
*/
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_3);
gen_or(b0, b1);
/*
* Now add the check for Ethernet_II frames, and
* do that before checking for the other frame
* types.
*/
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
(bpf_int32)ETHERTYPE_IPX);
gen_or(b0, b1);
return b1;
case ETHERTYPE_ATALK:
case ETHERTYPE_AARP:
/*
* EtherTalk (AppleTalk protocols on Ethernet link
* layer) may use 802.2 encapsulation.
*/
/*
* Check for 802.2 encapsulation (EtherTalk phase 2?);
* we check for the 802.2 protocol type in the
* "Ethernet type" field.
*/
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2);
/*
* 802.2-encapsulated ETHERTYPE_ATALK packets are
* SNAP packets with an organization code of
* 0x080007 (Apple, for Appletalk) and a protocol
* type of ETHERTYPE_ATALK (Appletalk).
*
* 802.2-encapsulated ETHERTYPE_AARP packets are
* SNAP packets with an organization code of
* 0x000000 (encapsulated Ethernet) and a protocol
* type of ETHERTYPE_AARP (Appletalk ARP).
*/
if (proto == ETHERTYPE_ATALK)
b1 = gen_snap(0x080007, ETHERTYPE_ATALK);
else /* proto == ETHERTYPE_AARP */
b1 = gen_snap(0x000000, ETHERTYPE_AARP);
gen_and(b0, b1);
/*
* Check for Ethernet encapsulation (Ethertalk
* phase 1?); we just check for the Ethernet
* protocol type.
*/
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
gen_or(b0, b1);
return b1;
default:
if (proto <= ETHERMTU) {
/*
* This is an LLC SAP value, so the frames
* that match would be 802.2 frames.
* Check for the 802.2 protocol type
* in the "Ethernet type" field, and
* then check the DSAP.
*/
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
LINUX_SLL_P_802_2);
b1 = gen_cmp(OR_LINK, off_macpl, BPF_B,
(bpf_int32)proto);
gen_and(b0, b1);
return b1;
} else {
/*
* This is an Ethernet type, so compare
* the length/type field with it (if
* the frame is an 802.2 frame, the length
* field will be <= ETHERMTU, and, as
* "proto" is > ETHERMTU, this test
* will fail and the frame won't match,
* which is what we want).
*/
return gen_cmp(OR_LINK, off_linktype, BPF_H,
(bpf_int32)proto);
}
}
}
static struct slist *
gen_load_prism_llprefixlen()
{
struct slist *s1, *s2;
struct slist *sjeq_avs_cookie;
struct slist *sjcommon;
/*
* This code is not compatible with the optimizer, as
* we are generating jmp instructions within a normal
* slist of instructions
*/
no_optimize = 1;
/*
* Generate code to load the length of the radio header into
* the register assigned to hold that length, if one has been
* assigned. (If one hasn't been assigned, no code we've
* generated uses that prefix, so we don't need to generate any
* code to load it.)
*
* Some Linux drivers use ARPHRD_IEEE80211_PRISM but sometimes
* or always use the AVS header rather than the Prism header.
* We load a 4-byte big-endian value at the beginning of the
* raw packet data, and see whether, when masked with 0xFFFFF000,
* it's equal to 0x80211000. If so, that indicates that it's
* an AVS header (the masked-out bits are the version number).
* Otherwise, it's a Prism header.
*
* XXX - the Prism header is also, in theory, variable-length,
* but no known software generates headers that aren't 144
* bytes long.
*/
if (reg_off_ll != -1) {
/*
* Load the cookie.
*/
s1 = new_stmt(BPF_LD|BPF_W|BPF_ABS);
s1->s.k = 0;
/*
* AND it with 0xFFFFF000.
*/
s2 = new_stmt(BPF_ALU|BPF_AND|BPF_K);
s2->s.k = 0xFFFFF000;
sappend(s1, s2);
/*
* Compare with 0x80211000.
*/
sjeq_avs_cookie = new_stmt(JMP(BPF_JEQ));
sjeq_avs_cookie->s.k = 0x80211000;
sappend(s1, sjeq_avs_cookie);
/*
* If it's AVS:
*
* The 4 bytes at an offset of 4 from the beginning of
* the AVS header are the length of the AVS header.
* That field is big-endian.
*/
s2 = new_stmt(BPF_LD|BPF_W|BPF_ABS);
s2->s.k = 4;
sappend(s1, s2);
sjeq_avs_cookie->s.jt = s2;
/*
* Now jump to the code to allocate a register
* into which to save the header length and
* store the length there. (The "jump always"
* instruction needs to have the k field set;
* it's added to the PC, so, as we're jumping
* over a single instruction, it should be 1.)
*/
sjcommon = new_stmt(JMP(BPF_JA));
sjcommon->s.k = 1;
sappend(s1, sjcommon);
/*
* Now for the code that handles the Prism header.
* Just load the length of the Prism header (144)
* into the A register. Have the test for an AVS
* header branch here if we don't have an AVS header.
*/
s2 = new_stmt(BPF_LD|BPF_W|BPF_IMM);
s2->s.k = 144;
sappend(s1, s2);
sjeq_avs_cookie->s.jf = s2;
/*
* Now allocate a register to hold that value and store
* it. The code for the AVS header will jump here after
* loading the length of the AVS header.
*/
s2 = new_stmt(BPF_ST);
s2->s.k = reg_off_ll;
sappend(s1, s2);
sjcommon->s.jf = s2;
/*
* Now move it into the X register.
*/
s2 = new_stmt(BPF_MISC|BPF_TAX);
sappend(s1, s2);
return (s1);
} else
return (NULL);
}
static struct slist *
gen_load_avs_llprefixlen()
{
struct slist *s1, *s2;
/*
* Generate code to load the length of the AVS header into
* the register assigned to hold that length, if one has been
* assigned. (If one hasn't been assigned, no code we've
* generated uses that prefix, so we don't need to generate any
* code to load it.)
*/
if (reg_off_ll != -1) {
/*
* The 4 bytes at an offset of 4 from the beginning of
* the AVS header are the length of the AVS header.
* That field is big-endian.
*/
s1 = new_stmt(BPF_LD|BPF_W|BPF_ABS);
s1->s.k = 4;
/*
* Now allocate a register to hold that value and store
* it.
*/
s2 = new_stmt(BPF_ST);
s2->s.k = reg_off_ll;
sappend(s1, s2);
/*
* Now move it into the X register.
*/
s2 = new_stmt(BPF_MISC|BPF_TAX);
sappend(s1, s2);
return (s1);
} else
return (NULL);
}
static struct slist *
gen_load_radiotap_llprefixlen()
{
struct slist *s1, *s2;
/*
* Generate code to load the length of the radiotap header into
* the register assigned to hold that length, if one has been
* assigned. (If one hasn't been assigned, no code we've
* generated uses that prefix, so we don't need to generate any
* code to load it.)
*/
if (reg_off_ll != -1) {
/*
* The 2 bytes at offsets of 2 and 3 from the beginning
* of the radiotap header are the length of the radiotap
* header; unfortunately, it's little-endian, so we have
* to load it a byte at a time and construct the value.
*/
/*
* Load the high-order byte, at an offset of 3, shift it
* left a byte, and put the result in the X register.
*/
s1 = new_stmt(BPF_LD|BPF_B|BPF_ABS);
s1->s.k = 3;
s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K);
sappend(s1, s2);
s2->s.k = 8;
s2 = new_stmt(BPF_MISC|BPF_TAX);
sappend(s1, s2);
/*
* Load the next byte, at an offset of 2, and OR the
* value from the X register into it.
*/
s2 = new_stmt(BPF_LD|BPF_B|BPF_ABS);
sappend(s1, s2);
s2->s.k = 2;
s2 = new_stmt(BPF_ALU|BPF_OR|BPF_X);
sappend(s1, s2);
/*
* Now allocate a register to hold that value and store
* it.
*/
s2 = new_stmt(BPF_ST);
s2->s.k = reg_off_ll;
sappend(s1, s2);
/*
* Now move it into the X register.
*/
s2 = new_stmt(BPF_MISC|BPF_TAX);
sappend(s1, s2);
return (s1);
} else
return (NULL);
}
/*
* At the moment we treat PPI as normal Radiotap encoded
* packets. The difference is in the function that generates
* the code at the beginning to compute the header length.
* Since this code generator of PPI supports bare 802.11
* encapsulation only (i.e. the encapsulated DLT should be
* DLT_IEEE802_11) we generate code to check for this too;
* that's done in finish_parse().
*/
static struct slist *
gen_load_ppi_llprefixlen()
{
struct slist *s1, *s2;
/*
* Generate code to load the length of the radiotap header
* into the register assigned to hold that length, if one has
* been assigned.
*/
if (reg_off_ll != -1) {
/*
* The 2 bytes at offsets of 2 and 3 from the beginning
* of the radiotap header are the length of the radiotap
* header; unfortunately, it's little-endian, so we have
* to load it a byte at a time and construct the value.
*/
/*
* Load the high-order byte, at an offset of 3, shift it
* left a byte, and put the result in the X register.
*/
s1 = new_stmt(BPF_LD|BPF_B|BPF_ABS);
s1->s.k = 3;
s2 = new_stmt(BPF_ALU|BPF_LSH|BPF_K);
sappend(s1, s2);
s2->s.k = 8;
s2 = new_stmt(BPF_MISC|BPF_TAX);
sappend(s1, s2);
/*
* Load the next byte, at an offset of 2, and OR the
* value from the X register into it.
*/
s2 = new_stmt(BPF_LD|BPF_B|BPF_ABS);
sappend(s1, s2);
s2->s.k = 2;
s2 = new_stmt(BPF_ALU|BPF_OR|BPF_X);
sappend(s1, s2);
/*
* Now allocate a register to hold that value and store
* it.
*/
s2 = new_stmt(BPF_ST);
s2->s.k = reg_off_ll;
sappend(s1, s2);
/*
* Now move it into the X register.
*/
s2 = new_stmt(BPF_MISC|BPF_TAX);
sappend(s1, s2);
return (s1);
} else
return (NULL);
}
/*
* Load a value relative to the beginning of the link-layer header after the 802.11
* header, i.e. LLC_SNAP.
* The link-layer header doesn't necessarily begin at the beginning
* of the packet data; there might be a variable-length prefix containing
* radio information.
*/
static struct slist *
gen_load_802_11_header_len(struct slist *s, struct slist *snext)
{
struct slist *s2;
struct slist *sjset_data_frame_1;
struct slist *sjset_data_frame_2;
struct slist *sjset_qos;
struct slist *sjset_radiotap_flags;
struct slist *sjset_radiotap_tsft;
struct slist *sjset_tsft_datapad, *sjset_notsft_datapad;
struct slist *s_roundup;
if (reg_off_macpl == -1) {
/*
* No register has been assigned to the offset of
* the MAC-layer payload, which means nobody needs
* it; don't bother computing it - just return
* what we already have.
*/
return (s);
}
/*
* This code is not compatible with the optimizer, as
* we are generating jmp instructions within a normal
* slist of instructions
*/
no_optimize = 1;
/*
* If "s" is non-null, it has code to arrange that the X register
* contains the length of the prefix preceding the link-layer
* header.
*
* Otherwise, the length of the prefix preceding the link-layer
* header is "off_ll".
*/
if (s == NULL) {
/*
* There is no variable-length header preceding the
* link-layer header.
*
* Load the length of the fixed-length prefix preceding
* the link-layer header (if any) into the X register,
* and store it in the reg_off_macpl register.
* That length is off_ll.
*/
s = new_stmt(BPF_LDX|BPF_IMM);
s->s.k = off_ll;
}
/*
* The X register contains the offset of the beginning of the
* link-layer header; add 24, which is the minimum length
* of the MAC header for a data frame, to that, and store it
* in reg_off_macpl, and then load the Frame Control field,
* which is at the offset in the X register, with an indexed load.
*/
s2 = new_stmt(BPF_MISC|BPF_TXA);
sappend(s, s2);
s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s2->s.k = 24;
sappend(s, s2);
s2 = new_stmt(BPF_ST);
s2->s.k = reg_off_macpl;
sappend(s, s2);
s2 = new_stmt(BPF_LD|BPF_IND|BPF_B);
s2->s.k = 0;
sappend(s, s2);
/*
* Check the Frame Control field to see if this is a data frame;
* a data frame has the 0x08 bit (b3) in that field set and the
* 0x04 bit (b2) clear.
*/
sjset_data_frame_1 = new_stmt(JMP(BPF_JSET));
sjset_data_frame_1->s.k = 0x08;
sappend(s, sjset_data_frame_1);
/*
* If b3 is set, test b2, otherwise go to the first statement of
* the rest of the program.
*/
sjset_data_frame_1->s.jt = sjset_data_frame_2 = new_stmt(JMP(BPF_JSET));
sjset_data_frame_2->s.k = 0x04;
sappend(s, sjset_data_frame_2);
sjset_data_frame_1->s.jf = snext;
/*
* If b2 is not set, this is a data frame; test the QoS bit.
* Otherwise, go to the first statement of the rest of the
* program.
*/
sjset_data_frame_2->s.jt = snext;
sjset_data_frame_2->s.jf = sjset_qos = new_stmt(JMP(BPF_JSET));
sjset_qos->s.k = 0x80; /* QoS bit */
sappend(s, sjset_qos);
/*
* If it's set, add 2 to reg_off_macpl, to skip the QoS
* field.
* Otherwise, go to the first statement of the rest of the
* program.
*/
sjset_qos->s.jt = s2 = new_stmt(BPF_LD|BPF_MEM);
s2->s.k = reg_off_macpl;
sappend(s, s2);
s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_IMM);
s2->s.k = 2;
sappend(s, s2);
s2 = new_stmt(BPF_ST);
s2->s.k = reg_off_macpl;
sappend(s, s2);
/*
* If we have a radiotap header, look at it to see whether
* there's Atheros padding between the MAC-layer header
* and the payload.
*
* Note: all of the fields in the radiotap header are
* little-endian, so we byte-swap all of the values
* we test against, as they will be loaded as big-endian
* values.
*/
if (linktype == DLT_IEEE802_11_RADIO) {
/*
* Is the IEEE80211_RADIOTAP_FLAGS bit (0x0000002) set
* in the presence flag?
*/
sjset_qos->s.jf = s2 = new_stmt(BPF_LD|BPF_ABS|BPF_W);
s2->s.k = 4;
sappend(s, s2);
sjset_radiotap_flags = new_stmt(JMP(BPF_JSET));
sjset_radiotap_flags->s.k = SWAPLONG(0x00000002);
sappend(s, sjset_radiotap_flags);
/*
* If not, skip all of this.
*/
sjset_radiotap_flags->s.jf = snext;
/*
* Otherwise, is the IEEE80211_RADIOTAP_TSFT bit set?
*/
sjset_radiotap_tsft = sjset_radiotap_flags->s.jt =
new_stmt(JMP(BPF_JSET));
sjset_radiotap_tsft->s.k = SWAPLONG(0x00000001);
sappend(s, sjset_radiotap_tsft);
/*
* If IEEE80211_RADIOTAP_TSFT is set, the flags field is
* at an offset of 16 from the beginning of the raw packet
* data (8 bytes for the radiotap header and 8 bytes for
* the TSFT field).
*
* Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
* is set.
*/
sjset_radiotap_tsft->s.jt = s2 = new_stmt(BPF_LD|BPF_ABS|BPF_B);
s2->s.k = 16;
sappend(s, s2);
sjset_tsft_datapad = new_stmt(JMP(BPF_JSET));
sjset_tsft_datapad->s.k = 0x20;
sappend(s, sjset_tsft_datapad);
/*
* If IEEE80211_RADIOTAP_TSFT is not set, the flags field is
* at an offset of 8 from the beginning of the raw packet
* data (8 bytes for the radiotap header).
*
* Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
* is set.
*/
sjset_radiotap_tsft->s.jf = s2 = new_stmt(BPF_LD|BPF_ABS|BPF_B);
s2->s.k = 8;
sappend(s, s2);
sjset_notsft_datapad = new_stmt(JMP(BPF_JSET));
sjset_notsft_datapad->s.k = 0x20;
sappend(s, sjset_notsft_datapad);
/*
* In either case, if IEEE80211_RADIOTAP_F_DATAPAD is
* set, round the length of the 802.11 header to
* a multiple of 4. Do that by adding 3 and then
* dividing by and multiplying by 4, which we do by
* ANDing with ~3.
*/
s_roundup = new_stmt(BPF_LD|BPF_MEM);
s_roundup->s.k = reg_off_macpl;
sappend(s, s_roundup);
s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_IMM);
s2->s.k = 3;
sappend(s, s2);
s2 = new_stmt(BPF_ALU|BPF_AND|BPF_IMM);
s2->s.k = ~3;
sappend(s, s2);
s2 = new_stmt(BPF_ST);
s2->s.k = reg_off_macpl;
sappend(s, s2);
sjset_tsft_datapad->s.jt = s_roundup;
sjset_tsft_datapad->s.jf = snext;
sjset_notsft_datapad->s.jt = s_roundup;
sjset_notsft_datapad->s.jf = snext;
} else
sjset_qos->s.jf = snext;
return s;
}
static void
insert_compute_vloffsets(b)
struct block *b;
{
struct slist *s;
/*
* For link-layer types that have a variable-length header
* preceding the link-layer header, generate code to load
* the offset of the link-layer header into the register
* assigned to that offset, if any.
*/
switch (linktype) {
case DLT_PRISM_HEADER:
s = gen_load_prism_llprefixlen();
break;
case DLT_IEEE802_11_RADIO_AVS:
s = gen_load_avs_llprefixlen();
break;
case DLT_IEEE802_11_RADIO:
s = gen_load_radiotap_llprefixlen();
break;
case DLT_PPI:
s = gen_load_ppi_llprefixlen();
break;
default:
s = NULL;
break;
}
/*
* For link-layer types that have a variable-length link-layer
* header, generate code to load the offset of the MAC-layer
* payload into the register assigned to that offset, if any.
*/
switch (linktype) {
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
s = gen_load_802_11_header_len(s, b->stmts);
break;
}
/*
* If we have any offset-loading code, append all the
* existing statements in the block to those statements,
* and make the resulting list the list of statements
* for the block.
*/
if (s != NULL) {
sappend(s, b->stmts);
b->stmts = s;
}
}
static struct block *
gen_ppi_dlt_check(void)
{
struct slist *s_load_dlt;
struct block *b;
if (linktype == DLT_PPI)
{
/* Create the statements that check for the DLT
*/
s_load_dlt = new_stmt(BPF_LD|BPF_W|BPF_ABS);
s_load_dlt->s.k = 4;
b = new_block(JMP(BPF_JEQ));
b->stmts = s_load_dlt;
b->s.k = SWAPLONG(DLT_IEEE802_11);
}
else
{
b = NULL;
}
return b;
}
static struct slist *
gen_prism_llprefixlen(void)
{
struct slist *s;
if (reg_off_ll == -1) {
/*
* We haven't yet assigned a register for the length
* of the radio header; allocate one.
*/
reg_off_ll = alloc_reg();
}
/*
* Load the register containing the radio length
* into the X register.
*/
s = new_stmt(BPF_LDX|BPF_MEM);
s->s.k = reg_off_ll;
return s;
}
static struct slist *
gen_avs_llprefixlen(void)
{
struct slist *s;
if (reg_off_ll == -1) {
/*
* We haven't yet assigned a register for the length
* of the AVS header; allocate one.
*/
reg_off_ll = alloc_reg();
}
/*
* Load the register containing the AVS length
* into the X register.
*/
s = new_stmt(BPF_LDX|BPF_MEM);
s->s.k = reg_off_ll;
return s;
}
static struct slist *
gen_radiotap_llprefixlen(void)
{
struct slist *s;
if (reg_off_ll == -1) {
/*
* We haven't yet assigned a register for the length
* of the radiotap header; allocate one.
*/
reg_off_ll = alloc_reg();
}
/*
* Load the register containing the radiotap length
* into the X register.
*/
s = new_stmt(BPF_LDX|BPF_MEM);
s->s.k = reg_off_ll;
return s;
}
/*
* At the moment we treat PPI as normal Radiotap encoded
* packets. The difference is in the function that generates
* the code at the beginning to compute the header length.
* Since this code generator of PPI supports bare 802.11
* encapsulation only (i.e. the encapsulated DLT should be
* DLT_IEEE802_11) we generate code to check for this too.
*/
static struct slist *
gen_ppi_llprefixlen(void)
{
struct slist *s;
if (reg_off_ll == -1) {
/*
* We haven't yet assigned a register for the length
* of the radiotap header; allocate one.
*/
reg_off_ll = alloc_reg();
}
/*
* Load the register containing the PPI length
* into the X register.
*/
s = new_stmt(BPF_LDX|BPF_MEM);
s->s.k = reg_off_ll;
return s;
}
/*
* Generate code to compute the link-layer header length, if necessary,
* putting it into the X register, and to return either a pointer to a
* "struct slist" for the list of statements in that code, or NULL if
* no code is necessary.
*/
static struct slist *
gen_llprefixlen(void)
{
switch (linktype) {
case DLT_PRISM_HEADER:
return gen_prism_llprefixlen();
case DLT_IEEE802_11_RADIO_AVS:
return gen_avs_llprefixlen();
case DLT_IEEE802_11_RADIO:
return gen_radiotap_llprefixlen();
case DLT_PPI:
return gen_ppi_llprefixlen();
default:
return NULL;
}
}
/*
* Generate code to load the register containing the offset of the
* MAC-layer payload into the X register; if no register for that offset
* has been allocated, allocate it first.
*/
static struct slist *
gen_off_macpl(void)
{
struct slist *s;
if (off_macpl_is_variable) {
if (reg_off_macpl == -1) {
/*
* We haven't yet assigned a register for the offset
* of the MAC-layer payload; allocate one.
*/
reg_off_macpl = alloc_reg();
}
/*
* Load the register containing the offset of the MAC-layer
* payload into the X register.
*/
s = new_stmt(BPF_LDX|BPF_MEM);
s->s.k = reg_off_macpl;
return s;
} else {
/*
* That offset isn't variable, so we don't need to
* generate any code.
*/
return NULL;
}
}
/*
* Map an Ethernet type to the equivalent PPP type.
*/
static int
ethertype_to_ppptype(proto)
int proto;
{
switch (proto) {
case ETHERTYPE_IP:
proto = PPP_IP;
break;
case ETHERTYPE_IPV6:
proto = PPP_IPV6;
break;
case ETHERTYPE_DN:
proto = PPP_DECNET;
break;
case ETHERTYPE_ATALK:
proto = PPP_APPLE;
break;
case ETHERTYPE_NS:
proto = PPP_NS;
break;
case LLCSAP_ISONS:
proto = PPP_OSI;
break;
case LLCSAP_8021D:
/*
* I'm assuming the "Bridging PDU"s that go
* over PPP are Spanning Tree Protocol
* Bridging PDUs.
*/
proto = PPP_BRPDU;
break;
case LLCSAP_IPX:
proto = PPP_IPX;
break;
}
return (proto);
}
/*
* Generate code to match a particular packet type by matching the
* link-layer type field or fields in the 802.2 LLC header.
*
* "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
* value, if <= ETHERMTU.
*/
static struct block *
gen_linktype(proto)
register int proto;
{
struct block *b0, *b1, *b2;
/* are we checking MPLS-encapsulated packets? */
if (label_stack_depth > 0) {
switch (proto) {
case ETHERTYPE_IP:
case PPP_IP:
/* FIXME add other L3 proto IDs */
return gen_mpls_linktype(Q_IP);
case ETHERTYPE_IPV6:
case PPP_IPV6:
/* FIXME add other L3 proto IDs */
return gen_mpls_linktype(Q_IPV6);
default:
bpf_error("unsupported protocol over mpls");
/* NOTREACHED */
}
}
/*
* Are we testing PPPoE packets?
*/
if (is_pppoes) {
/*
* The PPPoE session header is part of the
* MAC-layer payload, so all references
* should be relative to the beginning of
* that payload.
*/
/*
* We use Ethernet protocol types inside libpcap;
* map them to the corresponding PPP protocol types.
*/
proto = ethertype_to_ppptype(proto);
return gen_cmp(OR_MACPL, off_linktype, BPF_H, (bpf_int32)proto);
}
switch (linktype) {
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
return gen_ether_linktype(proto);
/*NOTREACHED*/
break;
case DLT_C_HDLC:
switch (proto) {
case LLCSAP_ISONS:
proto = (proto << 8 | LLCSAP_ISONS);
/* fall through */
default:
return gen_cmp(OR_LINK, off_linktype, BPF_H,
(bpf_int32)proto);
/*NOTREACHED*/
break;
}
break;
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
/*
* Check that we have a data frame.
*/
b0 = gen_check_802_11_data_frame();
/*
* Now check for the specified link-layer type.
*/
b1 = gen_llc_linktype(proto);
gen_and(b0, b1);
return b1;
/*NOTREACHED*/
break;
case DLT_FDDI:
/*
* XXX - check for asynchronous frames, as per RFC 1103.
*/
return gen_llc_linktype(proto);
/*NOTREACHED*/
break;
case DLT_IEEE802:
/*
* XXX - check for LLC PDUs, as per IEEE 802.5.
*/
return gen_llc_linktype(proto);
/*NOTREACHED*/
break;
case DLT_ATM_RFC1483:
case DLT_ATM_CLIP:
case DLT_IP_OVER_FC:
return gen_llc_linktype(proto);
/*NOTREACHED*/
break;
case DLT_SUNATM:
/*
* If "is_lane" is set, check for a LANE-encapsulated
* version of this protocol, otherwise check for an
* LLC-encapsulated version of this protocol.
*
* We assume LANE means Ethernet, not Token Ring.
*/
if (is_lane) {
/*
* Check that the packet doesn't begin with an
* LE Control marker. (We've already generated
* a test for LANE.)
*/
b0 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H,
0xFF00);
gen_not(b0);
/*
* Now generate an Ethernet test.
*/
b1 = gen_ether_linktype(proto);
gen_and(b0, b1);
return b1;
} else {
/*
* Check for LLC encapsulation and then check the
* protocol.
*/
b0 = gen_atmfield_code(A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
b1 = gen_llc_linktype(proto);
gen_and(b0, b1);
return b1;
}
/*NOTREACHED*/
break;
case DLT_LINUX_SLL:
return gen_linux_sll_linktype(proto);
/*NOTREACHED*/
break;
case DLT_SLIP:
case DLT_SLIP_BSDOS:
case DLT_RAW:
/*
* These types don't provide any type field; packets
* are always IPv4 or IPv6.
*
* XXX - for IPv4, check for a version number of 4, and,
* for IPv6, check for a version number of 6?
*/
switch (proto) {
case ETHERTYPE_IP:
/* Check for a version number of 4. */
return gen_mcmp(OR_LINK, 0, BPF_B, 0x40, 0xF0);
case ETHERTYPE_IPV6:
/* Check for a version number of 6. */
return gen_mcmp(OR_LINK, 0, BPF_B, 0x60, 0xF0);
default:
return gen_false(); /* always false */
}
/*NOTREACHED*/
break;
case DLT_IPV4:
/*
* Raw IPv4, so no type field.
*/
if (proto == ETHERTYPE_IP)
return gen_true(); /* always true */
/* Checking for something other than IPv4; always false */
return gen_false();
/*NOTREACHED*/
break;
case DLT_IPV6:
/*
* Raw IPv6, so no type field.
*/
if (proto == ETHERTYPE_IPV6)
return gen_true(); /* always true */
/* Checking for something other than IPv6; always false */
return gen_false();
/*NOTREACHED*/
break;
case DLT_PPP:
case DLT_PPP_PPPD:
case DLT_PPP_SERIAL:
case DLT_PPP_ETHER:
/*
* We use Ethernet protocol types inside libpcap;
* map them to the corresponding PPP protocol types.
*/
proto = ethertype_to_ppptype(proto);
return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
/*NOTREACHED*/
break;
case DLT_PPP_BSDOS:
/*
* We use Ethernet protocol types inside libpcap;
* map them to the corresponding PPP protocol types.
*/
switch (proto) {
case ETHERTYPE_IP:
/*
* Also check for Van Jacobson-compressed IP.
* XXX - do this for other forms of PPP?
*/
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_IP);
b1 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_VJC);
gen_or(b0, b1);
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_VJNC);
gen_or(b1, b0);
return b0;
default:
proto = ethertype_to_ppptype(proto);
return gen_cmp(OR_LINK, off_linktype, BPF_H,
(bpf_int32)proto);
}
/*NOTREACHED*/
break;
case DLT_NULL:
case DLT_LOOP:
case DLT_ENC:
/*
* For DLT_NULL, the link-layer header is a 32-bit
* word containing an AF_ value in *host* byte order,
* and for DLT_ENC, the link-layer header begins
* with a 32-bit work containing an AF_ value in
* host byte order.
*
* In addition, if we're reading a saved capture file,
* the host byte order in the capture may not be the
* same as the host byte order on this machine.
*
* For DLT_LOOP, the link-layer header is a 32-bit
* word containing an AF_ value in *network* byte order.
*
* XXX - AF_ values may, unfortunately, be platform-
* dependent; for example, FreeBSD's AF_INET6 is 24
* whilst NetBSD's and OpenBSD's is 26.
*
* This means that, when reading a capture file, just
* checking for our AF_INET6 value won't work if the
* capture file came from another OS.
*/
switch (proto) {
case ETHERTYPE_IP:
proto = AF_INET;
break;
#ifdef INET6
case ETHERTYPE_IPV6:
proto = AF_INET6;
break;
#endif
default:
/*
* Not a type on which we support filtering.
* XXX - support those that have AF_ values
* #defined on this platform, at least?
*/
return gen_false();
}
if (linktype == DLT_NULL || linktype == DLT_ENC) {
/*
* The AF_ value is in host byte order, but
* the BPF interpreter will convert it to
* network byte order.
*
* If this is a save file, and it's from a
* machine with the opposite byte order to
* ours, we byte-swap the AF_ value.
*
* Then we run it through "htonl()", and
* generate code to compare against the result.
*/
if (bpf_pcap->sf.rfile != NULL &&
bpf_pcap->sf.swapped)
proto = SWAPLONG(proto);
proto = htonl(proto);
}
return (gen_cmp(OR_LINK, 0, BPF_W, (bpf_int32)proto));
#ifdef HAVE_NET_PFVAR_H
case DLT_PFLOG:
/*
* af field is host byte order in contrast to the rest of
* the packet.
*/
if (proto == ETHERTYPE_IP)
return (gen_cmp(OR_LINK, offsetof(struct pfloghdr, af),
BPF_B, (bpf_int32)AF_INET));
else if (proto == ETHERTYPE_IPV6)
return (gen_cmp(OR_LINK, offsetof(struct pfloghdr, af),
BPF_B, (bpf_int32)AF_INET6));
else
return gen_false();
/*NOTREACHED*/
break;
#endif /* HAVE_NET_PFVAR_H */
case DLT_ARCNET:
case DLT_ARCNET_LINUX:
/*
* XXX should we check for first fragment if the protocol
* uses PHDS?
*/
switch (proto) {
default:
return gen_false();
case ETHERTYPE_IPV6:
return (gen_cmp(OR_LINK, off_linktype, BPF_B,
(bpf_int32)ARCTYPE_INET6));
case ETHERTYPE_IP:
b0 = gen_cmp(OR_LINK, off_linktype, BPF_B,
(bpf_int32)ARCTYPE_IP);
b1 = gen_cmp(OR_LINK, off_linktype, BPF_B,
(bpf_int32)ARCTYPE_IP_OLD);
gen_or(b0, b1);
return (b1);
case ETHERTYPE_ARP:
b0 = gen_cmp(OR_LINK, off_linktype, BPF_B,
(bpf_int32)ARCTYPE_ARP);
b1 = gen_cmp(OR_LINK, off_linktype, BPF_B,
(bpf_int32)ARCTYPE_ARP_OLD);
gen_or(b0, b1);
return (b1);
case ETHERTYPE_REVARP:
return (gen_cmp(OR_LINK, off_linktype, BPF_B,
(bpf_int32)ARCTYPE_REVARP));
case ETHERTYPE_ATALK:
return (gen_cmp(OR_LINK, off_linktype, BPF_B,
(bpf_int32)ARCTYPE_ATALK));
}
/*NOTREACHED*/
break;
case DLT_LTALK:
switch (proto) {
case ETHERTYPE_ATALK:
return gen_true();
default:
return gen_false();
}
/*NOTREACHED*/
break;
case DLT_FRELAY:
/*
* XXX - assumes a 2-byte Frame Relay header with
* DLCI and flags. What if the address is longer?
*/
switch (proto) {
case ETHERTYPE_IP:
/*
* Check for the special NLPID for IP.
*/
return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | 0xcc);
case ETHERTYPE_IPV6:
/*
* Check for the special NLPID for IPv6.
*/
return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | 0x8e);
case LLCSAP_ISONS:
/*
* Check for several OSI protocols.
*
* Frame Relay packets typically have an OSI
* NLPID at the beginning; we check for each
* of them.
*
* What we check for is the NLPID and a frame
* control field of UI, i.e. 0x03 followed
* by the NLPID.
*/
b0 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO8473_CLNP);
b1 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO9542_ESIS);
b2 = gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | ISO10589_ISIS);
gen_or(b1, b2);
gen_or(b0, b2);
return b2;
default:
return gen_false();
}
/*NOTREACHED*/
break;
case DLT_MFR:
bpf_error("Multi-link Frame Relay link-layer type filtering not implemented");
case DLT_JUNIPER_MFR:
case DLT_JUNIPER_MLFR:
case DLT_JUNIPER_MLPPP:
case DLT_JUNIPER_ATM1:
case DLT_JUNIPER_ATM2:
case DLT_JUNIPER_PPPOE:
case DLT_JUNIPER_PPPOE_ATM:
case DLT_JUNIPER_GGSN:
case DLT_JUNIPER_ES:
case DLT_JUNIPER_MONITOR:
case DLT_JUNIPER_SERVICES:
case DLT_JUNIPER_ETHER:
case DLT_JUNIPER_PPP:
case DLT_JUNIPER_FRELAY:
case DLT_JUNIPER_CHDLC:
case DLT_JUNIPER_VP:
case DLT_JUNIPER_ST:
case DLT_JUNIPER_ISM:
case DLT_JUNIPER_VS:
case DLT_JUNIPER_SRX_E2E:
case DLT_JUNIPER_FIBRECHANNEL:
case DLT_JUNIPER_ATM_CEMIC:
/* just lets verify the magic number for now -
* on ATM we may have up to 6 different encapsulations on the wire
* and need a lot of heuristics to figure out that the payload
* might be;
*
* FIXME encapsulation specific BPF_ filters
*/
return gen_mcmp(OR_LINK, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */
case DLT_IPNET:
return gen_ipnet_linktype(proto);
case DLT_LINUX_IRDA:
bpf_error("IrDA link-layer type filtering not implemented");
case DLT_DOCSIS:
bpf_error("DOCSIS link-layer type filtering not implemented");
case DLT_MTP2:
case DLT_MTP2_WITH_PHDR:
bpf_error("MTP2 link-layer type filtering not implemented");
case DLT_ERF:
bpf_error("ERF link-layer type filtering not implemented");
case DLT_PFSYNC:
bpf_error("PFSYNC link-layer type filtering not implemented");
case DLT_LINUX_LAPD:
bpf_error("LAPD link-layer type filtering not implemented");
case DLT_USB:
case DLT_USB_LINUX:
case DLT_USB_LINUX_MMAPPED:
bpf_error("USB link-layer type filtering not implemented");
case DLT_BLUETOOTH_HCI_H4:
case DLT_BLUETOOTH_HCI_H4_WITH_PHDR:
bpf_error("Bluetooth link-layer type filtering not implemented");
case DLT_CAN20B:
case DLT_CAN_SOCKETCAN:
bpf_error("CAN link-layer type filtering not implemented");
case DLT_IEEE802_15_4:
case DLT_IEEE802_15_4_LINUX:
case DLT_IEEE802_15_4_NONASK_PHY:
case DLT_IEEE802_15_4_NOFCS:
bpf_error("IEEE 802.15.4 link-layer type filtering not implemented");
case DLT_IEEE802_16_MAC_CPS_RADIO:
bpf_error("IEEE 802.16 link-layer type filtering not implemented");
case DLT_SITA:
bpf_error("SITA link-layer type filtering not implemented");
case DLT_RAIF1:
bpf_error("RAIF1 link-layer type filtering not implemented");
case DLT_IPMB:
bpf_error("IPMB link-layer type filtering not implemented");
case DLT_AX25_KISS:
bpf_error("AX.25 link-layer type filtering not implemented");
}
/*
* All the types that have no encapsulation should either be
* handled as DLT_SLIP, DLT_SLIP_BSDOS, and DLT_RAW are, if
* all packets are IP packets, or should be handled in some
* special case, if none of them are (if some are and some
* aren't, the lack of encapsulation is a problem, as we'd
* have to find some other way of determining the packet type).
*
* Therefore, if "off_linktype" is -1, there's an error.
*/
if (off_linktype == (u_int)-1)
abort();
/*
* Any type not handled above should always have an Ethernet
* type at an offset of "off_linktype".
*/
return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32)proto);
}
/*
* Check for an LLC SNAP packet with a given organization code and
* protocol type; we check the entire contents of the 802.2 LLC and
* snap headers, checking for DSAP and SSAP of SNAP and a control
* field of 0x03 in the LLC header, and for the specified organization
* code and protocol type in the SNAP header.
*/
static struct block *
gen_snap(orgcode, ptype)
bpf_u_int32 orgcode;
bpf_u_int32 ptype;
{
u_char snapblock[8];
snapblock[0] = LLCSAP_SNAP; /* DSAP = SNAP */
snapblock[1] = LLCSAP_SNAP; /* SSAP = SNAP */
snapblock[2] = 0x03; /* control = UI */
snapblock[3] = (orgcode >> 16); /* upper 8 bits of organization code */
snapblock[4] = (orgcode >> 8); /* middle 8 bits of organization code */
snapblock[5] = (orgcode >> 0); /* lower 8 bits of organization code */
snapblock[6] = (ptype >> 8); /* upper 8 bits of protocol type */
snapblock[7] = (ptype >> 0); /* lower 8 bits of protocol type */
return gen_bcmp(OR_MACPL, 0, 8, snapblock);
}
/*
* Generate code to match a particular packet type, for link-layer types
* using 802.2 LLC headers.
*
* This is *NOT* used for Ethernet; "gen_ether_linktype()" is used
* for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues.
*
* "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
* value, if <= ETHERMTU. We use that to determine whether to
* match the DSAP or both DSAP and LSAP or to check the OUI and
* protocol ID in a SNAP header.
*/
static struct block *
gen_llc_linktype(proto)
int proto;
{
/*
* XXX - handle token-ring variable-length header.
*/
switch (proto) {
case LLCSAP_IP:
case LLCSAP_ISONS:
case LLCSAP_NETBEUI:
/*
* XXX - should we check both the DSAP and the
* SSAP, like this, or should we check just the
* DSAP, as we do for other types <= ETHERMTU
* (i.e., other SAP values)?
*/
return gen_cmp(OR_MACPL, 0, BPF_H, (bpf_u_int32)
((proto << 8) | proto));
case LLCSAP_IPX:
/*
* XXX - are there ever SNAP frames for IPX on
* non-Ethernet 802.x networks?
*/
return gen_cmp(OR_MACPL, 0, BPF_B,
(bpf_int32)LLCSAP_IPX);
case ETHERTYPE_ATALK:
/*
* 802.2-encapsulated ETHERTYPE_ATALK packets are
* SNAP packets with an organization code of
* 0x080007 (Apple, for Appletalk) and a protocol
* type of ETHERTYPE_ATALK (Appletalk).
*
* XXX - check for an organization code of
* encapsulated Ethernet as well?
*/
return gen_snap(0x080007, ETHERTYPE_ATALK);
default:
/*
* XXX - we don't have to check for IPX 802.3
* here, but should we check for the IPX Ethertype?
*/
if (proto <= ETHERMTU) {
/*
* This is an LLC SAP value, so check
* the DSAP.
*/
return gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32)proto);
} else {
/*
* This is an Ethernet type; we assume that it's
* unlikely that it'll appear in the right place
* at random, and therefore check only the
* location that would hold the Ethernet type
* in a SNAP frame with an organization code of
* 0x000000 (encapsulated Ethernet).
*
* XXX - if we were to check for the SNAP DSAP and
* LSAP, as per XXX, and were also to check for an
* organization code of 0x000000 (encapsulated
* Ethernet), we'd do
*
* return gen_snap(0x000000, proto);
*
* here; for now, we don't, as per the above.
* I don't know whether it's worth the extra CPU
* time to do the right check or not.
*/
return gen_cmp(OR_MACPL, 6, BPF_H, (bpf_int32)proto);
}
}
}
static struct block *
gen_hostop(addr, mask, dir, proto, src_off, dst_off)
bpf_u_int32 addr;
bpf_u_int32 mask;
int dir, proto;
u_int src_off, dst_off;
{
struct block *b0, *b1;
u_int offset;
switch (dir) {
case Q_SRC:
offset = src_off;
break;
case Q_DST:
offset = dst_off;
break;
case Q_AND:
b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
gen_or(b0, b1);
return b1;
default:
abort();
}
b0 = gen_linktype(proto);
b1 = gen_mcmp(OR_NET, offset, BPF_W, (bpf_int32)addr, mask);
gen_and(b0, b1);
return b1;
}
#ifdef INET6
static struct block *
gen_hostop6(addr, mask, dir, proto, src_off, dst_off)
struct in6_addr *addr;
struct in6_addr *mask;
int dir, proto;
u_int src_off, dst_off;
{
struct block *b0, *b1;
u_int offset;
u_int32_t *a, *m;
switch (dir) {
case Q_SRC:
offset = src_off;
break;
case Q_DST:
offset = dst_off;
break;
case Q_AND:
b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off);
gen_or(b0, b1);
return b1;
default:
abort();
}
/* this order is important */
a = (u_int32_t *)addr;
m = (u_int32_t *)mask;
b1 = gen_mcmp(OR_NET, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
b0 = gen_mcmp(OR_NET, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
gen_and(b0, b1);
b0 = gen_mcmp(OR_NET, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
gen_and(b0, b1);
b0 = gen_mcmp(OR_NET, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
gen_and(b0, b1);
b0 = gen_linktype(proto);
gen_and(b0, b1);
return b1;
}
#endif
static struct block *
gen_ehostop(eaddr, dir)
register const u_char *eaddr;
register int dir;
{
register struct block *b0, *b1;
switch (dir) {
case Q_SRC:
return gen_bcmp(OR_LINK, off_mac + 6, 6, eaddr);
case Q_DST:
return gen_bcmp(OR_LINK, off_mac + 0, 6, eaddr);
case Q_AND:
b0 = gen_ehostop(eaddr, Q_SRC);
b1 = gen_ehostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_ehostop(eaddr, Q_SRC);
b1 = gen_ehostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error("'addr1' is only supported on 802.11 with 802.11 headers");
break;
case Q_ADDR2:
bpf_error("'addr2' is only supported on 802.11 with 802.11 headers");
break;
case Q_ADDR3:
bpf_error("'addr3' is only supported on 802.11 with 802.11 headers");
break;
case Q_ADDR4:
bpf_error("'addr4' is only supported on 802.11 with 802.11 headers");
break;
case Q_RA:
bpf_error("'ra' is only supported on 802.11 with 802.11 headers");
break;
case Q_TA:
bpf_error("'ta' is only supported on 802.11 with 802.11 headers");
break;
}
abort();
/* NOTREACHED */
}
/*
* Like gen_ehostop, but for DLT_FDDI
*/
static struct block *
gen_fhostop(eaddr, dir)
register const u_char *eaddr;
register int dir;
{
struct block *b0, *b1;
switch (dir) {
case Q_SRC:
#ifdef PCAP_FDDIPAD
return gen_bcmp(OR_LINK, 6 + 1 + pcap_fddipad, 6, eaddr);
#else
return gen_bcmp(OR_LINK, 6 + 1, 6, eaddr);
#endif
case Q_DST:
#ifdef PCAP_FDDIPAD
return gen_bcmp(OR_LINK, 0 + 1 + pcap_fddipad, 6, eaddr);
#else
return gen_bcmp(OR_LINK, 0 + 1, 6, eaddr);
#endif
case Q_AND:
b0 = gen_fhostop(eaddr, Q_SRC);
b1 = gen_fhostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_fhostop(eaddr, Q_SRC);
b1 = gen_fhostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error("'addr1' is only supported on 802.11");
break;
case Q_ADDR2:
bpf_error("'addr2' is only supported on 802.11");
break;
case Q_ADDR3:
bpf_error("'addr3' is only supported on 802.11");
break;
case Q_ADDR4:
bpf_error("'addr4' is only supported on 802.11");
break;
case Q_RA:
bpf_error("'ra' is only supported on 802.11");
break;
case Q_TA:
bpf_error("'ta' is only supported on 802.11");
break;
}
abort();
/* NOTREACHED */
}
/*
* Like gen_ehostop, but for DLT_IEEE802 (Token Ring)
*/
static struct block *
gen_thostop(eaddr, dir)
register const u_char *eaddr;
register int dir;
{
register struct block *b0, *b1;
switch (dir) {
case Q_SRC:
return gen_bcmp(OR_LINK, 8, 6, eaddr);
case Q_DST:
return gen_bcmp(OR_LINK, 2, 6, eaddr);
case Q_AND:
b0 = gen_thostop(eaddr, Q_SRC);
b1 = gen_thostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_thostop(eaddr, Q_SRC);
b1 = gen_thostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error("'addr1' is only supported on 802.11");
break;
case Q_ADDR2:
bpf_error("'addr2' is only supported on 802.11");
break;
case Q_ADDR3:
bpf_error("'addr3' is only supported on 802.11");
break;
case Q_ADDR4:
bpf_error("'addr4' is only supported on 802.11");
break;
case Q_RA:
bpf_error("'ra' is only supported on 802.11");
break;
case Q_TA:
bpf_error("'ta' is only supported on 802.11");
break;
}
abort();
/* NOTREACHED */
}
/*
* Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and
* various 802.11 + radio headers.
*/
static struct block *
gen_wlanhostop(eaddr, dir)
register const u_char *eaddr;
register int dir;
{
register struct block *b0, *b1, *b2;
register struct slist *s;
#ifdef ENABLE_WLAN_FILTERING_PATCH
/*
* TODO GV 20070613
* We need to disable the optimizer because the optimizer is buggy
* and wipes out some LD instructions generated by the below
* code to validate the Frame Control bits
*/
no_optimize = 1;
#endif /* ENABLE_WLAN_FILTERING_PATCH */
switch (dir) {
case Q_SRC:
/*
* Oh, yuk.
*
* For control frames, there is no SA.
*
* For management frames, SA is at an
* offset of 10 from the beginning of
* the packet.
*
* For data frames, SA is at an offset
* of 10 from the beginning of the packet
* if From DS is clear, at an offset of
* 16 from the beginning of the packet
* if From DS is set and To DS is clear,
* and an offset of 24 from the beginning
* of the packet if From DS is set and To DS
* is set.
*/
/*
* Generate the tests to be done for data frames
* with From DS set.
*
* First, check for To DS set, i.e. check "link[1] & 0x01".
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x01; /* To DS */
b1->stmts = s;
/*
* If To DS is set, the SA is at 24.
*/
b0 = gen_bcmp(OR_LINK, 24, 6, eaddr);
gen_and(b1, b0);
/*
* Now, check for To DS not set, i.e. check
* "!(link[1] & 0x01)".
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x01; /* To DS */
b2->stmts = s;
gen_not(b2);
/*
* If To DS is not set, the SA is at 16.
*/
b1 = gen_bcmp(OR_LINK, 16, 6, eaddr);
gen_and(b2, b1);
/*
* Now OR together the last two checks. That gives
* the complete set of checks for data frames with
* From DS set.
*/
gen_or(b1, b0);
/*
* Now check for From DS being set, and AND that with
* the ORed-together checks.
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x02; /* From DS */
b1->stmts = s;
gen_and(b1, b0);
/*
* Now check for data frames with From DS not set.
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x02; /* From DS */
b2->stmts = s;
gen_not(b2);
/*
* If From DS isn't set, the SA is at 10.
*/
b1 = gen_bcmp(OR_LINK, 10, 6, eaddr);
gen_and(b2, b1);
/*
* Now OR together the checks for data frames with
* From DS not set and for data frames with From DS
* set; that gives the checks done for data frames.
*/
gen_or(b1, b0);
/*
* Now check for a data frame.
* I.e, check "link[0] & 0x08".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* AND that with the checks done for data frames.
*/
gen_and(b1, b0);
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "!(link[0] & 0x08)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x08;
b2->stmts = s;
gen_not(b2);
/*
* For management frames, the SA is at 10.
*/
b1 = gen_bcmp(OR_LINK, 10, 6, eaddr);
gen_and(b2, b1);
/*
* OR that with the checks done for data frames.
* That gives the checks done for management and
* data frames.
*/
gen_or(b1, b0);
/*
* If the low-order bit of the type value is 1,
* this is either a control frame or a frame
* with a reserved type, and thus not a
* frame with an SA.
*
* I.e., check "!(link[0] & 0x04)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x04;
b1->stmts = s;
gen_not(b1);
/*
* AND that with the checks for data and management
* frames.
*/
gen_and(b1, b0);
return b0;
case Q_DST:
/*
* Oh, yuk.
*
* For control frames, there is no DA.
*
* For management frames, DA is at an
* offset of 4 from the beginning of
* the packet.
*
* For data frames, DA is at an offset
* of 4 from the beginning of the packet
* if To DS is clear and at an offset of
* 16 from the beginning of the packet
* if To DS is set.
*/
/*
* Generate the tests to be done for data frames.
*
* First, check for To DS set, i.e. "link[1] & 0x01".
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x01; /* To DS */
b1->stmts = s;
/*
* If To DS is set, the DA is at 16.
*/
b0 = gen_bcmp(OR_LINK, 16, 6, eaddr);
gen_and(b1, b0);
/*
* Now, check for To DS not set, i.e. check
* "!(link[1] & 0x01)".
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x01; /* To DS */
b2->stmts = s;
gen_not(b2);
/*
* If To DS is not set, the DA is at 4.
*/
b1 = gen_bcmp(OR_LINK, 4, 6, eaddr);
gen_and(b2, b1);
/*
* Now OR together the last two checks. That gives
* the complete set of checks for data frames.
*/
gen_or(b1, b0);
/*
* Now check for a data frame.
* I.e, check "link[0] & 0x08".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* AND that with the checks done for data frames.
*/
gen_and(b1, b0);
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "!(link[0] & 0x08)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x08;
b2->stmts = s;
gen_not(b2);
/*
* For management frames, the DA is at 4.
*/
b1 = gen_bcmp(OR_LINK, 4, 6, eaddr);
gen_and(b2, b1);
/*
* OR that with the checks done for data frames.
* That gives the checks done for management and
* data frames.
*/
gen_or(b1, b0);
/*
* If the low-order bit of the type value is 1,
* this is either a control frame or a frame
* with a reserved type, and thus not a
* frame with an SA.
*
* I.e., check "!(link[0] & 0x04)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x04;
b1->stmts = s;
gen_not(b1);
/*
* AND that with the checks for data and management
* frames.
*/
gen_and(b1, b0);
return b0;
case Q_RA:
/*
* Not present in management frames; addr1 in other
* frames.
*/
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "(link[0] & 0x08)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* Check addr1.
*/
b0 = gen_bcmp(OR_LINK, 4, 6, eaddr);
/*
* AND that with the check of addr1.
*/
gen_and(b1, b0);
return (b0);
case Q_TA:
/*
* Not present in management frames; addr2, if present,
* in other frames.
*/
/*
* Not present in CTS or ACK control frames.
*/
b0 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
IEEE80211_FC0_TYPE_MASK);
gen_not(b0);
b1 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
IEEE80211_FC0_SUBTYPE_MASK);
gen_not(b1);
b2 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
IEEE80211_FC0_SUBTYPE_MASK);
gen_not(b2);
gen_and(b1, b2);
gen_or(b0, b2);
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "(link[0] & 0x08)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* AND that with the check for frames other than
* CTS and ACK frames.
*/
gen_and(b1, b2);
/*
* Check addr2.
*/
b1 = gen_bcmp(OR_LINK, 10, 6, eaddr);
gen_and(b2, b1);
return b1;
/*
* XXX - add BSSID keyword?
*/
case Q_ADDR1:
return (gen_bcmp(OR_LINK, 4, 6, eaddr));
case Q_ADDR2:
/*
* Not present in CTS or ACK control frames.
*/
b0 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
IEEE80211_FC0_TYPE_MASK);
gen_not(b0);
b1 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
IEEE80211_FC0_SUBTYPE_MASK);
gen_not(b1);
b2 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
IEEE80211_FC0_SUBTYPE_MASK);
gen_not(b2);
gen_and(b1, b2);
gen_or(b0, b2);
b1 = gen_bcmp(OR_LINK, 10, 6, eaddr);
gen_and(b2, b1);
return b1;
case Q_ADDR3:
/*
* Not present in control frames.
*/
b0 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
IEEE80211_FC0_TYPE_MASK);
gen_not(b0);
b1 = gen_bcmp(OR_LINK, 16, 6, eaddr);
gen_and(b0, b1);
return b1;
case Q_ADDR4:
/*
* Present only if the direction mask has both "From DS"
* and "To DS" set. Neither control frames nor management
* frames should have both of those set, so we don't
* check the frame type.
*/
b0 = gen_mcmp(OR_LINK, 1, BPF_B,
IEEE80211_FC1_DIR_DSTODS, IEEE80211_FC1_DIR_MASK);
b1 = gen_bcmp(OR_LINK, 24, 6, eaddr);
gen_and(b0, b1);
return b1;
case Q_AND:
b0 = gen_wlanhostop(eaddr, Q_SRC);
b1 = gen_wlanhostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_wlanhostop(eaddr, Q_SRC);
b1 = gen_wlanhostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
}
abort();
/* NOTREACHED */
}
/*
* Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel.
* (We assume that the addresses are IEEE 48-bit MAC addresses,
* as the RFC states.)
*/
static struct block *
gen_ipfchostop(eaddr, dir)
register const u_char *eaddr;
register int dir;
{
register struct block *b0, *b1;
switch (dir) {
case Q_SRC:
return gen_bcmp(OR_LINK, 10, 6, eaddr);
case Q_DST:
return gen_bcmp(OR_LINK, 2, 6, eaddr);
case Q_AND:
b0 = gen_ipfchostop(eaddr, Q_SRC);
b1 = gen_ipfchostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_ipfchostop(eaddr, Q_SRC);
b1 = gen_ipfchostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error("'addr1' is only supported on 802.11");
break;
case Q_ADDR2:
bpf_error("'addr2' is only supported on 802.11");
break;
case Q_ADDR3:
bpf_error("'addr3' is only supported on 802.11");
break;
case Q_ADDR4:
bpf_error("'addr4' is only supported on 802.11");
break;
case Q_RA:
bpf_error("'ra' is only supported on 802.11");
break;
case Q_TA:
bpf_error("'ta' is only supported on 802.11");
break;
}
abort();
/* NOTREACHED */
}
/*
* This is quite tricky because there may be pad bytes in front of the
* DECNET header, and then there are two possible data packet formats that
* carry both src and dst addresses, plus 5 packet types in a format that
* carries only the src node, plus 2 types that use a different format and
* also carry just the src node.
*
* Yuck.
*
* Instead of doing those all right, we just look for data packets with
* 0 or 1 bytes of padding. If you want to look at other packets, that
* will require a lot more hacking.
*
* To add support for filtering on DECNET "areas" (network numbers)
* one would want to add a "mask" argument to this routine. That would
* make the filter even more inefficient, although one could be clever
* and not generate masking instructions if the mask is 0xFFFF.
*/
static struct block *
gen_dnhostop(addr, dir)
bpf_u_int32 addr;
int dir;
{
struct block *b0, *b1, *b2, *tmp;
u_int offset_lh; /* offset if long header is received */
u_int offset_sh; /* offset if short header is received */
switch (dir) {
case Q_DST:
offset_sh = 1; /* follows flags */
offset_lh = 7; /* flgs,darea,dsubarea,HIORD */
break;
case Q_SRC:
offset_sh = 3; /* follows flags, dstnode */
offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */
break;
case Q_AND:
/* Inefficient because we do our Calvinball dance twice */
b0 = gen_dnhostop(addr, Q_SRC);
b1 = gen_dnhostop(addr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
/* Inefficient because we do our Calvinball dance twice */
b0 = gen_dnhostop(addr, Q_SRC);
b1 = gen_dnhostop(addr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ISO:
bpf_error("ISO host filtering not implemented");
default:
abort();
}
b0 = gen_linktype(ETHERTYPE_DN);
/* Check for pad = 1, long header case */
tmp = gen_mcmp(OR_NET, 2, BPF_H,
(bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF));
b1 = gen_cmp(OR_NET, 2 + 1 + offset_lh,
BPF_H, (bpf_int32)ntohs((u_short)addr));
gen_and(tmp, b1);
/* Check for pad = 0, long header case */
tmp = gen_mcmp(OR_NET, 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7);
b2 = gen_cmp(OR_NET, 2 + offset_lh, BPF_H, (bpf_int32)ntohs((u_short)addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Check for pad = 1, short header case */
tmp = gen_mcmp(OR_NET, 2, BPF_H,
(bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF));
b2 = gen_cmp(OR_NET, 2 + 1 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Check for pad = 0, short header case */
tmp = gen_mcmp(OR_NET, 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7);
b2 = gen_cmp(OR_NET, 2 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Combine with test for linktype */
gen_and(b0, b1);
return b1;
}
/*
* Generate a check for IPv4 or IPv6 for MPLS-encapsulated packets;
* test the bottom-of-stack bit, and then check the version number
* field in the IP header.
*/
static struct block *
gen_mpls_linktype(proto)
int proto;
{
struct block *b0, *b1;
switch (proto) {
case Q_IP:
/* match the bottom-of-stack bit */
b0 = gen_mcmp(OR_NET, -2, BPF_B, 0x01, 0x01);
/* match the IPv4 version number */
b1 = gen_mcmp(OR_NET, 0, BPF_B, 0x40, 0xf0);
gen_and(b0, b1);
return b1;
case Q_IPV6:
/* match the bottom-of-stack bit */
b0 = gen_mcmp(OR_NET, -2, BPF_B, 0x01, 0x01);
/* match the IPv4 version number */
b1 = gen_mcmp(OR_NET, 0, BPF_B, 0x60, 0xf0);
gen_and(b0, b1);
return b1;
default:
abort();
}
}
static struct block *
gen_host(addr, mask, proto, dir, type)
bpf_u_int32 addr;
bpf_u_int32 mask;
int proto;
int dir;
int type;
{
struct block *b0, *b1;
const char *typestr;
if (type == Q_NET)
typestr = "net";
else
typestr = "host";
switch (proto) {
case Q_DEFAULT:
b0 = gen_host(addr, mask, Q_IP, dir, type);
/*
* Only check for non-IPv4 addresses if we're not
* checking MPLS-encapsulated packets.
*/
if (label_stack_depth == 0) {
b1 = gen_host(addr, mask, Q_ARP, dir, type);
gen_or(b0, b1);
b0 = gen_host(addr, mask, Q_RARP, dir, type);
gen_or(b1, b0);
}
return b0;
case Q_IP:
return gen_hostop(addr, mask, dir, ETHERTYPE_IP, 12, 16);
case Q_RARP:
return gen_hostop(addr, mask, dir, ETHERTYPE_REVARP, 14, 24);
case Q_ARP:
return gen_hostop(addr, mask, dir, ETHERTYPE_ARP, 14, 24);
case Q_TCP:
bpf_error("'tcp' modifier applied to %s", typestr);
case Q_SCTP:
bpf_error("'sctp' modifier applied to %s", typestr);
case Q_UDP:
bpf_error("'udp' modifier applied to %s", typestr);
case Q_ICMP:
bpf_error("'icmp' modifier applied to %s", typestr);
case Q_IGMP:
bpf_error("'igmp' modifier applied to %s", typestr);
case Q_IGRP:
bpf_error("'igrp' modifier applied to %s", typestr);
case Q_PIM:
bpf_error("'pim' modifier applied to %s", typestr);
case Q_VRRP:
bpf_error("'vrrp' modifier applied to %s", typestr);
case Q_CARP:
bpf_error("'carp' modifier applied to %s", typestr);
case Q_ATALK:
bpf_error("ATALK host filtering not implemented");
case Q_AARP:
bpf_error("AARP host filtering not implemented");
case Q_DECNET:
return gen_dnhostop(addr, dir);
case Q_SCA:
bpf_error("SCA host filtering not implemented");
case Q_LAT:
bpf_error("LAT host filtering not implemented");
case Q_MOPDL:
bpf_error("MOPDL host filtering not implemented");
case Q_MOPRC:
bpf_error("MOPRC host filtering not implemented");
case Q_IPV6:
bpf_error("'ip6' modifier applied to ip host");
case Q_ICMPV6:
bpf_error("'icmp6' modifier applied to %s", typestr);
case Q_AH:
bpf_error("'ah' modifier applied to %s", typestr);
case Q_ESP:
bpf_error("'esp' modifier applied to %s", typestr);
case Q_ISO:
bpf_error("ISO host filtering not implemented");
case Q_ESIS:
bpf_error("'esis' modifier applied to %s", typestr);
case Q_ISIS:
bpf_error("'isis' modifier applied to %s", typestr);
case Q_CLNP:
bpf_error("'clnp' modifier applied to %s", typestr);
case Q_STP:
bpf_error("'stp' modifier applied to %s", typestr);
case Q_IPX:
bpf_error("IPX host filtering not implemented");
case Q_NETBEUI:
bpf_error("'netbeui' modifier applied to %s", typestr);
case Q_RADIO:
bpf_error("'radio' modifier applied to %s", typestr);
default:
abort();
}
/* NOTREACHED */
}
#ifdef INET6
static struct block *
gen_host6(addr, mask, proto, dir, type)
struct in6_addr *addr;
struct in6_addr *mask;
int proto;
int dir;
int type;
{
const char *typestr;
if (type == Q_NET)
typestr = "net";
else
typestr = "host";
switch (proto) {
case Q_DEFAULT:
return gen_host6(addr, mask, Q_IPV6, dir, type);
case Q_IP:
bpf_error("'ip' modifier applied to ip6 %s", typestr);
case Q_RARP:
bpf_error("'rarp' modifier applied to ip6 %s", typestr);
case Q_ARP:
bpf_error("'arp' modifier applied to ip6 %s", typestr);
case Q_SCTP:
bpf_error("'sctp' modifier applied to %s", typestr);
case Q_TCP:
bpf_error("'tcp' modifier applied to %s", typestr);
case Q_UDP:
bpf_error("'udp' modifier applied to %s", typestr);
case Q_ICMP:
bpf_error("'icmp' modifier applied to %s", typestr);
case Q_IGMP:
bpf_error("'igmp' modifier applied to %s", typestr);
case Q_IGRP:
bpf_error("'igrp' modifier applied to %s", typestr);
case Q_PIM:
bpf_error("'pim' modifier applied to %s", typestr);
case Q_VRRP:
bpf_error("'vrrp' modifier applied to %s", typestr);
case Q_CARP:
bpf_error("'carp' modifier applied to %s", typestr);
case Q_ATALK:
bpf_error("ATALK host filtering not implemented");
case Q_AARP:
bpf_error("AARP host filtering not implemented");
case Q_DECNET:
bpf_error("'decnet' modifier applied to ip6 %s", typestr);
case Q_SCA:
bpf_error("SCA host filtering not implemented");
case Q_LAT:
bpf_error("LAT host filtering not implemented");
case Q_MOPDL:
bpf_error("MOPDL host filtering not implemented");
case Q_MOPRC:
bpf_error("MOPRC host filtering not implemented");
case Q_IPV6:
return gen_hostop6(addr, mask, dir, ETHERTYPE_IPV6, 8, 24);
case Q_ICMPV6:
bpf_error("'icmp6' modifier applied to %s", typestr);
case Q_AH:
bpf_error("'ah' modifier applied to %s", typestr);
case Q_ESP:
bpf_error("'esp' modifier applied to %s", typestr);
case Q_ISO:
bpf_error("ISO host filtering not implemented");
case Q_ESIS:
bpf_error("'esis' modifier applied to %s", typestr);
case Q_ISIS:
bpf_error("'isis' modifier applied to %s", typestr);
case Q_CLNP:
bpf_error("'clnp' modifier applied to %s", typestr);
case Q_STP:
bpf_error("'stp' modifier applied to %s", typestr);
case Q_IPX:
bpf_error("IPX host filtering not implemented");
case Q_NETBEUI:
bpf_error("'netbeui' modifier applied to %s", typestr);
case Q_RADIO:
bpf_error("'radio' modifier applied to %s", typestr);
default:
abort();
}
/* NOTREACHED */
}
#endif
#ifndef INET6
static struct block *
gen_gateway(eaddr, alist, proto, dir)
const u_char *eaddr;
bpf_u_int32 **alist;
int proto;
int dir;
{
struct block *b0, *b1, *tmp;
if (dir != 0)
bpf_error("direction applied to 'gateway'");
switch (proto) {
case Q_DEFAULT:
case Q_IP:
case Q_ARP:
case Q_RARP:
switch (linktype) {
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
b0 = gen_ehostop(eaddr, Q_OR);
break;
case DLT_FDDI:
b0 = gen_fhostop(eaddr, Q_OR);
break;
case DLT_IEEE802:
b0 = gen_thostop(eaddr, Q_OR);
break;
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
b0 = gen_wlanhostop(eaddr, Q_OR);
break;
case DLT_SUNATM:
if (!is_lane)
bpf_error(
"'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
/*
* Check that the packet doesn't begin with an
* LE Control marker. (We've already generated
* a test for LANE.)
*/
b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS,
BPF_H, 0xFF00);
gen_not(b1);
/*
* Now check the MAC address.
*/
b0 = gen_ehostop(eaddr, Q_OR);
gen_and(b1, b0);
break;
case DLT_IP_OVER_FC:
b0 = gen_ipfchostop(eaddr, Q_OR);
break;
default:
bpf_error(
"'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
}
b1 = gen_host(**alist++, 0xffffffff, proto, Q_OR, Q_HOST);
while (*alist) {
tmp = gen_host(**alist++, 0xffffffff, proto, Q_OR,
Q_HOST);
gen_or(b1, tmp);
b1 = tmp;
}
gen_not(b1);
gen_and(b0, b1);
return b1;
}
bpf_error("illegal modifier of 'gateway'");
/* NOTREACHED */
}
#endif
struct block *
gen_proto_abbrev(proto)
int proto;
{
struct block *b0;
struct block *b1;
switch (proto) {
case Q_SCTP:
b1 = gen_proto(IPPROTO_SCTP, Q_IP, Q_DEFAULT);
b0 = gen_proto(IPPROTO_SCTP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_TCP:
b1 = gen_proto(IPPROTO_TCP, Q_IP, Q_DEFAULT);
b0 = gen_proto(IPPROTO_TCP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_UDP:
b1 = gen_proto(IPPROTO_UDP, Q_IP, Q_DEFAULT);
b0 = gen_proto(IPPROTO_UDP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ICMP:
b1 = gen_proto(IPPROTO_ICMP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_IGMP
#define IPPROTO_IGMP 2
#endif
case Q_IGMP:
b1 = gen_proto(IPPROTO_IGMP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_IGRP
#define IPPROTO_IGRP 9
#endif
case Q_IGRP:
b1 = gen_proto(IPPROTO_IGRP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_PIM
#define IPPROTO_PIM 103
#endif
case Q_PIM:
b1 = gen_proto(IPPROTO_PIM, Q_IP, Q_DEFAULT);
b0 = gen_proto(IPPROTO_PIM, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
#ifndef IPPROTO_VRRP
#define IPPROTO_VRRP 112
#endif
case Q_VRRP:
b1 = gen_proto(IPPROTO_VRRP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_CARP
#define IPPROTO_CARP 112
#endif
case Q_CARP:
b1 = gen_proto(IPPROTO_CARP, Q_IP, Q_DEFAULT);
break;
case Q_IP:
b1 = gen_linktype(ETHERTYPE_IP);
break;
case Q_ARP:
b1 = gen_linktype(ETHERTYPE_ARP);
break;
case Q_RARP:
b1 = gen_linktype(ETHERTYPE_REVARP);
break;
case Q_LINK:
bpf_error("link layer applied in wrong context");
case Q_ATALK:
b1 = gen_linktype(ETHERTYPE_ATALK);
break;
case Q_AARP:
b1 = gen_linktype(ETHERTYPE_AARP);
break;
case Q_DECNET:
b1 = gen_linktype(ETHERTYPE_DN);
break;
case Q_SCA:
b1 = gen_linktype(ETHERTYPE_SCA);
break;
case Q_LAT:
b1 = gen_linktype(ETHERTYPE_LAT);
break;
case Q_MOPDL:
b1 = gen_linktype(ETHERTYPE_MOPDL);
break;
case Q_MOPRC:
b1 = gen_linktype(ETHERTYPE_MOPRC);
break;
case Q_IPV6:
b1 = gen_linktype(ETHERTYPE_IPV6);
break;
#ifndef IPPROTO_ICMPV6
#define IPPROTO_ICMPV6 58
#endif
case Q_ICMPV6:
b1 = gen_proto(IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT);
break;
#ifndef IPPROTO_AH
#define IPPROTO_AH 51
#endif
case Q_AH:
b1 = gen_proto(IPPROTO_AH, Q_IP, Q_DEFAULT);
b0 = gen_proto(IPPROTO_AH, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
#ifndef IPPROTO_ESP
#define IPPROTO_ESP 50
#endif
case Q_ESP:
b1 = gen_proto(IPPROTO_ESP, Q_IP, Q_DEFAULT);
b0 = gen_proto(IPPROTO_ESP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISO:
b1 = gen_linktype(LLCSAP_ISONS);
break;
case Q_ESIS:
b1 = gen_proto(ISO9542_ESIS, Q_ISO, Q_DEFAULT);
break;
case Q_ISIS:
b1 = gen_proto(ISO10589_ISIS, Q_ISO, Q_DEFAULT);
break;
case Q_ISIS_L1: /* all IS-IS Level1 PDU-Types */
b0 = gen_proto(ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
gen_or(b0, b1);
b0 = gen_proto(ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_L2: /* all IS-IS Level2 PDU-Types */
b0 = gen_proto(ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
gen_or(b0, b1);
b0 = gen_proto(ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_IIH: /* all IS-IS Hello PDU-Types */
b0 = gen_proto(ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_LSP:
b0 = gen_proto(ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_SNP:
b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
b0 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_CSNP:
b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_ISIS_PSNP:
b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
b1 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
gen_or(b0, b1);
break;
case Q_CLNP:
b1 = gen_proto(ISO8473_CLNP, Q_ISO, Q_DEFAULT);
break;
case Q_STP:
b1 = gen_linktype(LLCSAP_8021D);
break;
case Q_IPX:
b1 = gen_linktype(LLCSAP_IPX);
break;
case Q_NETBEUI:
b1 = gen_linktype(LLCSAP_NETBEUI);
break;
case Q_RADIO:
bpf_error("'radio' is not a valid protocol type");
default:
abort();
}
return b1;
}
static struct block *
gen_ipfrag()
{
struct slist *s;
struct block *b;
/* not IPv4 frag other than the first frag */
s = gen_load_a(OR_NET, 6, BPF_H);
b = new_block(JMP(BPF_JSET));
b->s.k = 0x1fff;
b->stmts = s;
gen_not(b);
return b;
}
/*
* Generate a comparison to a port value in the transport-layer header
* at the specified offset from the beginning of that header.
*
* XXX - this handles a variable-length prefix preceding the link-layer
* header, such as the radiotap or AVS radio prefix, but doesn't handle
* variable-length link-layer headers (such as Token Ring or 802.11
* headers).
*/
static struct block *
gen_portatom(off, v)
int off;
bpf_int32 v;
{
return gen_cmp(OR_TRAN_IPV4, off, BPF_H, v);
}
static struct block *
gen_portatom6(off, v)
int off;
bpf_int32 v;
{
return gen_cmp(OR_TRAN_IPV6, off, BPF_H, v);
}
struct block *
gen_portop(port, proto, dir)
int port, proto, dir;
{
struct block *b0, *b1, *tmp;
/* ip proto 'proto' and not a fragment other than the first fragment */
tmp = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32)proto);
b0 = gen_ipfrag();
gen_and(tmp, b0);
switch (dir) {
case Q_SRC:
b1 = gen_portatom(0, (bpf_int32)port);
break;
case Q_DST:
b1 = gen_portatom(2, (bpf_int32)port);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portatom(0, (bpf_int32)port);
b1 = gen_portatom(2, (bpf_int32)port);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portatom(0, (bpf_int32)port);
b1 = gen_portatom(2, (bpf_int32)port);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_port(port, ip_proto, dir)
int port;
int ip_proto;
int dir;
{
struct block *b0, *b1, *tmp;
/*
* ether proto ip
*
* For FDDI, RFC 1188 says that SNAP encapsulation is used,
* not LLC encapsulation with LLCSAP_IP.
*
* For IEEE 802 networks - which includes 802.5 token ring
* (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
* says that SNAP encapsulation is used, not LLC encapsulation
* with LLCSAP_IP.
*
* For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
* RFC 2225 say that SNAP encapsulation is used, not LLC
* encapsulation with LLCSAP_IP.
*
* So we always check for ETHERTYPE_IP.
*/
b0 = gen_linktype(ETHERTYPE_IP);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
case IPPROTO_SCTP:
b1 = gen_portop(port, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portop(port, IPPROTO_TCP, dir);
b1 = gen_portop(port, IPPROTO_UDP, dir);
gen_or(tmp, b1);
tmp = gen_portop(port, IPPROTO_SCTP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
struct block *
gen_portop6(port, proto, dir)
int port, proto, dir;
{
struct block *b0, *b1, *tmp;
/* ip6 proto 'proto' */
/* XXX - catch the first fragment of a fragmented packet? */
b0 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32)proto);
switch (dir) {
case Q_SRC:
b1 = gen_portatom6(0, (bpf_int32)port);
break;
case Q_DST:
b1 = gen_portatom6(2, (bpf_int32)port);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portatom6(0, (bpf_int32)port);
b1 = gen_portatom6(2, (bpf_int32)port);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portatom6(0, (bpf_int32)port);
b1 = gen_portatom6(2, (bpf_int32)port);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_port6(port, ip_proto, dir)
int port;
int ip_proto;
int dir;
{
struct block *b0, *b1, *tmp;
/* link proto ip6 */
b0 = gen_linktype(ETHERTYPE_IPV6);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
case IPPROTO_SCTP:
b1 = gen_portop6(port, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portop6(port, IPPROTO_TCP, dir);
b1 = gen_portop6(port, IPPROTO_UDP, dir);
gen_or(tmp, b1);
tmp = gen_portop6(port, IPPROTO_SCTP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
/* gen_portrange code */
static struct block *
gen_portrangeatom(off, v1, v2)
int off;
bpf_int32 v1, v2;
{
struct block *b1, *b2;
if (v1 > v2) {
/*
* Reverse the order of the ports, so v1 is the lower one.
*/
bpf_int32 vtemp;
vtemp = v1;
v1 = v2;
v2 = vtemp;
}
b1 = gen_cmp_ge(OR_TRAN_IPV4, off, BPF_H, v1);
b2 = gen_cmp_le(OR_TRAN_IPV4, off, BPF_H, v2);
gen_and(b1, b2);
return b2;
}
struct block *
gen_portrangeop(port1, port2, proto, dir)
int port1, port2;
int proto;
int dir;
{
struct block *b0, *b1, *tmp;
/* ip proto 'proto' and not a fragment other than the first fragment */
tmp = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32)proto);
b0 = gen_ipfrag();
gen_and(tmp, b0);
switch (dir) {
case Q_SRC:
b1 = gen_portrangeatom(0, (bpf_int32)port1, (bpf_int32)port2);
break;
case Q_DST:
b1 = gen_portrangeatom(2, (bpf_int32)port1, (bpf_int32)port2);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portrangeatom(0, (bpf_int32)port1, (bpf_int32)port2);
b1 = gen_portrangeatom(2, (bpf_int32)port1, (bpf_int32)port2);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portrangeatom(0, (bpf_int32)port1, (bpf_int32)port2);
b1 = gen_portrangeatom(2, (bpf_int32)port1, (bpf_int32)port2);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_portrange(port1, port2, ip_proto, dir)
int port1, port2;
int ip_proto;
int dir;
{
struct block *b0, *b1, *tmp;
/* link proto ip */
b0 = gen_linktype(ETHERTYPE_IP);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
case IPPROTO_SCTP:
b1 = gen_portrangeop(port1, port2, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portrangeop(port1, port2, IPPROTO_TCP, dir);
b1 = gen_portrangeop(port1, port2, IPPROTO_UDP, dir);
gen_or(tmp, b1);
tmp = gen_portrangeop(port1, port2, IPPROTO_SCTP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_portrangeatom6(off, v1, v2)
int off;
bpf_int32 v1, v2;
{
struct block *b1, *b2;
if (v1 > v2) {
/*
* Reverse the order of the ports, so v1 is the lower one.
*/
bpf_int32 vtemp;
vtemp = v1;
v1 = v2;
v2 = vtemp;
}
b1 = gen_cmp_ge(OR_TRAN_IPV6, off, BPF_H, v1);
b2 = gen_cmp_le(OR_TRAN_IPV6, off, BPF_H, v2);
gen_and(b1, b2);
return b2;
}
struct block *
gen_portrangeop6(port1, port2, proto, dir)
int port1, port2;
int proto;
int dir;
{
struct block *b0, *b1, *tmp;
/* ip6 proto 'proto' */
/* XXX - catch the first fragment of a fragmented packet? */
b0 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32)proto);
switch (dir) {
case Q_SRC:
b1 = gen_portrangeatom6(0, (bpf_int32)port1, (bpf_int32)port2);
break;
case Q_DST:
b1 = gen_portrangeatom6(2, (bpf_int32)port1, (bpf_int32)port2);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portrangeatom6(0, (bpf_int32)port1, (bpf_int32)port2);
b1 = gen_portrangeatom6(2, (bpf_int32)port1, (bpf_int32)port2);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portrangeatom6(0, (bpf_int32)port1, (bpf_int32)port2);
b1 = gen_portrangeatom6(2, (bpf_int32)port1, (bpf_int32)port2);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_portrange6(port1, port2, ip_proto, dir)
int port1, port2;
int ip_proto;
int dir;
{
struct block *b0, *b1, *tmp;
/* link proto ip6 */
b0 = gen_linktype(ETHERTYPE_IPV6);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
case IPPROTO_SCTP:
b1 = gen_portrangeop6(port1, port2, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portrangeop6(port1, port2, IPPROTO_TCP, dir);
b1 = gen_portrangeop6(port1, port2, IPPROTO_UDP, dir);
gen_or(tmp, b1);
tmp = gen_portrangeop6(port1, port2, IPPROTO_SCTP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static int
lookup_proto(name, proto)
register const char *name;
register int proto;
{
register int v;
switch (proto) {
case Q_DEFAULT:
case Q_IP:
case Q_IPV6:
v = pcap_nametoproto(name);
if (v == PROTO_UNDEF)
bpf_error("unknown ip proto '%s'", name);
break;
case Q_LINK:
/* XXX should look up h/w protocol type based on linktype */
v = pcap_nametoeproto(name);
if (v == PROTO_UNDEF) {
v = pcap_nametollc(name);
if (v == PROTO_UNDEF)
bpf_error("unknown ether proto '%s'", name);
}
break;
case Q_ISO:
if (strcmp(name, "esis") == 0)
v = ISO9542_ESIS;
else if (strcmp(name, "isis") == 0)
v = ISO10589_ISIS;
else if (strcmp(name, "clnp") == 0)
v = ISO8473_CLNP;
else
bpf_error("unknown osi proto '%s'", name);
break;
default:
v = PROTO_UNDEF;
break;
}
return v;
}
#if 0
struct stmt *
gen_joinsp(s, n)
struct stmt **s;
int n;
{
return NULL;
}
#endif
static struct block *
gen_protochain(v, proto, dir)
int v;
int proto;
int dir;
{
#ifdef NO_PROTOCHAIN
return gen_proto(v, proto, dir);
#else
struct block *b0, *b;
struct slist *s[100];
int fix2, fix3, fix4, fix5;
int ahcheck, again, end;
int i, max;
int reg2 = alloc_reg();
memset(s, 0, sizeof(s));
fix2 = fix3 = fix4 = fix5 = 0;
switch (proto) {
case Q_IP:
case Q_IPV6:
break;
case Q_DEFAULT:
b0 = gen_protochain(v, Q_IP, dir);
b = gen_protochain(v, Q_IPV6, dir);
gen_or(b0, b);
return b;
default:
bpf_error("bad protocol applied for 'protochain'");
/*NOTREACHED*/
}
/*
* We don't handle variable-length prefixes before the link-layer
* header, or variable-length link-layer headers, here yet.
* We might want to add BPF instructions to do the protochain
* work, to simplify that and, on platforms that have a BPF
* interpreter with the new instructions, let the filtering
* be done in the kernel. (We already require a modified BPF
* engine to do the protochain stuff, to support backward
* branches, and backward branch support is unlikely to appear
* in kernel BPF engines.)
*/
switch (linktype) {
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
bpf_error("'protochain' not supported with 802.11");
}
no_optimize = 1; /*this code is not compatible with optimzer yet */
/*
* s[0] is a dummy entry to protect other BPF insn from damage
* by s[fix] = foo with uninitialized variable "fix". It is somewhat
* hard to find interdependency made by jump table fixup.
*/
i = 0;
s[i] = new_stmt(0); /*dummy*/
i++;
switch (proto) {
case Q_IP:
b0 = gen_linktype(ETHERTYPE_IP);
/* A = ip->ip_p */
s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B);
s[i]->s.k = off_macpl + off_nl + 9;
i++;
/* X = ip->ip_hl << 2 */
s[i] = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
s[i]->s.k = off_macpl + off_nl;
i++;
break;
case Q_IPV6:
b0 = gen_linktype(ETHERTYPE_IPV6);
/* A = ip6->ip_nxt */
s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B);
s[i]->s.k = off_macpl + off_nl + 6;
i++;
/* X = sizeof(struct ip6_hdr) */
s[i] = new_stmt(BPF_LDX|BPF_IMM);
s[i]->s.k = 40;
i++;
break;
default:
bpf_error("unsupported proto to gen_protochain");
/*NOTREACHED*/
}
/* again: if (A == v) goto end; else fall through; */
again = i;
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.k = v;
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
fix5 = i;
i++;
#ifndef IPPROTO_NONE
#define IPPROTO_NONE 59
#endif
/* if (A == IPPROTO_NONE) goto end */
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_NONE;
s[fix5]->s.jf = s[i];
fix2 = i;
i++;
if (proto == Q_IPV6) {
int v6start, v6end, v6advance, j;
v6start = i;
/* if (A == IPPROTO_HOPOPTS) goto v6advance */
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_HOPOPTS;
s[fix2]->s.jf = s[i];
i++;
/* if (A == IPPROTO_DSTOPTS) goto v6advance */
s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_DSTOPTS;
i++;
/* if (A == IPPROTO_ROUTING) goto v6advance */
s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_ROUTING;
i++;
/* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */
s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*later*/
s[i]->s.k = IPPROTO_FRAGMENT;
fix3 = i;
v6end = i;
i++;
/* v6advance: */
v6advance = i;
/*
* in short,
* A = P[X + packet head];
* X = X + (P[X + packet head + 1] + 1) * 8;
*/
/* A = P[X + packet head] */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_macpl + off_nl;
i++;
/* MEM[reg2] = A */
s[i] = new_stmt(BPF_ST);
s[i]->s.k = reg2;
i++;
/* A = P[X + packet head + 1]; */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_macpl + off_nl + 1;
i++;
/* A += 1 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 1;
i++;
/* A *= 8 */
s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K);
s[i]->s.k = 8;
i++;
/* A += X */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_X);
s[i]->s.k = 0;
i++;
/* X = A; */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = MEM[reg2] */
s[i] = new_stmt(BPF_LD|BPF_MEM);
s[i]->s.k = reg2;
i++;
/* goto again; (must use BPF_JA for backward jump) */
s[i] = new_stmt(BPF_JMP|BPF_JA);
s[i]->s.k = again - i - 1;
s[i - 1]->s.jf = s[i];
i++;
/* fixup */
for (j = v6start; j <= v6end; j++)
s[j]->s.jt = s[v6advance];
} else {
/* nop */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 0;
s[fix2]->s.jf = s[i];
i++;
}
/* ahcheck: */
ahcheck = i;
/* if (A == IPPROTO_AH) then fall through; else goto end; */
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*later*/
s[i]->s.k = IPPROTO_AH;
if (fix3)
s[fix3]->s.jf = s[ahcheck];
fix4 = i;
i++;
/*
* in short,
* A = P[X];
* X = X + (P[X + 1] + 2) * 4;
*/
/* A = X */
s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC|BPF_TXA);
i++;
/* A = P[X + packet head]; */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_macpl + off_nl;
i++;
/* MEM[reg2] = A */
s[i] = new_stmt(BPF_ST);
s[i]->s.k = reg2;
i++;
/* A = X */
s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC|BPF_TXA);
i++;
/* A += 1 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 1;
i++;
/* X = A */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = P[X + packet head] */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_macpl + off_nl;
i++;
/* A += 2 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 2;
i++;
/* A *= 4 */
s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K);
s[i]->s.k = 4;
i++;
/* X = A; */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = MEM[reg2] */
s[i] = new_stmt(BPF_LD|BPF_MEM);
s[i]->s.k = reg2;
i++;
/* goto again; (must use BPF_JA for backward jump) */
s[i] = new_stmt(BPF_JMP|BPF_JA);
s[i]->s.k = again - i - 1;
i++;
/* end: nop */
end = i;
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 0;
s[fix2]->s.jt = s[end];
s[fix4]->s.jf = s[end];
s[fix5]->s.jt = s[end];
i++;
/*
* make slist chain
*/
max = i;
for (i = 0; i < max - 1; i++)
s[i]->next = s[i + 1];
s[max - 1]->next = NULL;
/*
* emit final check
*/
b = new_block(JMP(BPF_JEQ));
b->stmts = s[1]; /*remember, s[0] is dummy*/
b->s.k = v;
free_reg(reg2);
gen_and(b0, b);
return b;
#endif
}
static struct block *
gen_check_802_11_data_frame()
{
struct slist *s;
struct block *b0, *b1;
/*
* A data frame has the 0x08 bit (b3) in the frame control field set
* and the 0x04 bit (b2) clear.
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b0 = new_block(JMP(BPF_JSET));
b0->s.k = 0x08;
b0->stmts = s;
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x04;
b1->stmts = s;
gen_not(b1);
gen_and(b1, b0);
return b0;
}
/*
* Generate code that checks whether the packet is a packet for protocol
* <proto> and whether the type field in that protocol's header has
* the value <v>, e.g. if <proto> is Q_IP, it checks whether it's an
* IP packet and checks the protocol number in the IP header against <v>.
*
* If <proto> is Q_DEFAULT, i.e. just "proto" was specified, it checks
* against Q_IP and Q_IPV6.
*/
static struct block *
gen_proto(v, proto, dir)
int v;
int proto;
int dir;
{
struct block *b0, *b1;
#ifndef CHASE_CHAIN
struct block *b2;
#endif
if (dir != Q_DEFAULT)
bpf_error("direction applied to 'proto'");
switch (proto) {
case Q_DEFAULT:
b0 = gen_proto(v, Q_IP, dir);
b1 = gen_proto(v, Q_IPV6, dir);
gen_or(b0, b1);
return b1;
case Q_IP:
/*
* For FDDI, RFC 1188 says that SNAP encapsulation is used,
* not LLC encapsulation with LLCSAP_IP.
*
* For IEEE 802 networks - which includes 802.5 token ring
* (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
* says that SNAP encapsulation is used, not LLC encapsulation
* with LLCSAP_IP.
*
* For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
* RFC 2225 say that SNAP encapsulation is used, not LLC
* encapsulation with LLCSAP_IP.
*
* So we always check for ETHERTYPE_IP.
*/
b0 = gen_linktype(ETHERTYPE_IP);
#ifndef CHASE_CHAIN
b1 = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32)v);
#else
b1 = gen_protochain(v, Q_IP);
#endif
gen_and(b0, b1);
return b1;
case Q_ISO:
switch (linktype) {
case DLT_FRELAY:
/*
* Frame Relay packets typically have an OSI
* NLPID at the beginning; "gen_linktype(LLCSAP_ISONS)"
* generates code to check for all the OSI
* NLPIDs, so calling it and then adding a check
* for the particular NLPID for which we're
* looking is bogus, as we can just check for
* the NLPID.
*
* What we check for is the NLPID and a frame
* control field value of UI, i.e. 0x03 followed
* by the NLPID.
*
* XXX - assumes a 2-byte Frame Relay header with
* DLCI and flags. What if the address is longer?
*
* XXX - what about SNAP-encapsulated frames?
*/
return gen_cmp(OR_LINK, 2, BPF_H, (0x03<<8) | v);
/*NOTREACHED*/
break;
case DLT_C_HDLC:
/*
* Cisco uses an Ethertype lookalike - for OSI,
* it's 0xfefe.
*/
b0 = gen_linktype(LLCSAP_ISONS<<8 | LLCSAP_ISONS);
/* OSI in C-HDLC is stuffed with a fudge byte */
b1 = gen_cmp(OR_NET_NOSNAP, 1, BPF_B, (long)v);
gen_and(b0, b1);
return b1;
default:
b0 = gen_linktype(LLCSAP_ISONS);
b1 = gen_cmp(OR_NET_NOSNAP, 0, BPF_B, (long)v);
gen_and(b0, b1);
return b1;
}
case Q_ISIS:
b0 = gen_proto(ISO10589_ISIS, Q_ISO, Q_DEFAULT);
/*
* 4 is the offset of the PDU type relative to the IS-IS
* header.
*/
b1 = gen_cmp(OR_NET_NOSNAP, 4, BPF_B, (long)v);
gen_and(b0, b1);
return b1;
case Q_ARP:
bpf_error("arp does not encapsulate another protocol");
/* NOTREACHED */
case Q_RARP:
bpf_error("rarp does not encapsulate another protocol");
/* NOTREACHED */
case Q_ATALK:
bpf_error("atalk encapsulation is not specifiable");
/* NOTREACHED */
case Q_DECNET:
bpf_error("decnet encapsulation is not specifiable");
/* NOTREACHED */
case Q_SCA:
bpf_error("sca does not encapsulate another protocol");
/* NOTREACHED */
case Q_LAT:
bpf_error("lat does not encapsulate another protocol");
/* NOTREACHED */
case Q_MOPRC:
bpf_error("moprc does not encapsulate another protocol");
/* NOTREACHED */
case Q_MOPDL:
bpf_error("mopdl does not encapsulate another protocol");
/* NOTREACHED */
case Q_LINK:
return gen_linktype(v);
case Q_UDP:
bpf_error("'udp proto' is bogus");
/* NOTREACHED */
case Q_TCP:
bpf_error("'tcp proto' is bogus");
/* NOTREACHED */
case Q_SCTP:
bpf_error("'sctp proto' is bogus");
/* NOTREACHED */
case Q_ICMP:
bpf_error("'icmp proto' is bogus");
/* NOTREACHED */
case Q_IGMP:
bpf_error("'igmp proto' is bogus");
/* NOTREACHED */
case Q_IGRP:
bpf_error("'igrp proto' is bogus");
/* NOTREACHED */
case Q_PIM:
bpf_error("'pim proto' is bogus");
/* NOTREACHED */
case Q_VRRP:
bpf_error("'vrrp proto' is bogus");
/* NOTREACHED */
case Q_CARP:
bpf_error("'carp proto' is bogus");
/* NOTREACHED */
case Q_IPV6:
b0 = gen_linktype(ETHERTYPE_IPV6);
#ifndef CHASE_CHAIN
/*
* Also check for a fragment header before the final
* header.
*/
b2 = gen_cmp(OR_NET, 6, BPF_B, IPPROTO_FRAGMENT);
b1 = gen_cmp(OR_NET, 40, BPF_B, (bpf_int32)v);
gen_and(b2, b1);
b2 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32)v);
gen_or(b2, b1);
#else
b1 = gen_protochain(v, Q_IPV6);
#endif
gen_and(b0, b1);
return b1;
case Q_ICMPV6:
bpf_error("'icmp6 proto' is bogus");
case Q_AH:
bpf_error("'ah proto' is bogus");
case Q_ESP:
bpf_error("'ah proto' is bogus");
case Q_STP:
bpf_error("'stp proto' is bogus");
case Q_IPX:
bpf_error("'ipx proto' is bogus");
case Q_NETBEUI:
bpf_error("'netbeui proto' is bogus");
case Q_RADIO:
bpf_error("'radio proto' is bogus");
default:
abort();
/* NOTREACHED */
}
/* NOTREACHED */
}
struct block *
gen_scode(name, q)
register const char *name;
struct qual q;
{
int proto = q.proto;
int dir = q.dir;
int tproto;
u_char *eaddr;
bpf_u_int32 mask, addr;
#ifndef INET6
bpf_u_int32 **alist;
#else
int tproto6;
struct sockaddr_in *sin4;
struct sockaddr_in6 *sin6;
struct addrinfo *res, *res0;
struct in6_addr mask128;
#endif /*INET6*/
struct block *b, *tmp;
int port, real_proto;
int port1, port2;
switch (q.addr) {
case Q_NET:
addr = pcap_nametonetaddr(name);
if (addr == 0)
bpf_error("unknown network '%s'", name);
/* Left justify network addr and calculate its network mask */
mask = 0xffffffff;
while (addr && (addr & 0xff000000) == 0) {
addr <<= 8;
mask <<= 8;
}
return gen_host(addr, mask, proto, dir, q.addr);
case Q_DEFAULT:
case Q_HOST:
if (proto == Q_LINK) {
switch (linktype) {
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown ether host '%s'", name);
b = gen_ehostop(eaddr, dir);
free(eaddr);
return b;
case DLT_FDDI:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown FDDI host '%s'", name);
b = gen_fhostop(eaddr, dir);
free(eaddr);
return b;
case DLT_IEEE802:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown token ring host '%s'", name);
b = gen_thostop(eaddr, dir);
free(eaddr);
return b;
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown 802.11 host '%s'", name);
b = gen_wlanhostop(eaddr, dir);
free(eaddr);
return b;
case DLT_IP_OVER_FC:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown Fibre Channel host '%s'", name);
b = gen_ipfchostop(eaddr, dir);
free(eaddr);
return b;
case DLT_SUNATM:
if (!is_lane)
break;
/*
* Check that the packet doesn't begin
* with an LE Control marker. (We've
* already generated a test for LANE.)
*/
tmp = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS,
BPF_H, 0xFF00);
gen_not(tmp);
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown ether host '%s'", name);
b = gen_ehostop(eaddr, dir);
gen_and(tmp, b);
free(eaddr);
return b;
}
bpf_error("only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name");
} else if (proto == Q_DECNET) {
unsigned short dn_addr = __pcap_nametodnaddr(name);
/*
* I don't think DECNET hosts can be multihomed, so
* there is no need to build up a list of addresses
*/
return (gen_host(dn_addr, 0, proto, dir, q.addr));
} else {
#ifndef INET6
alist = pcap_nametoaddr(name);
if (alist == NULL || *alist == NULL)
bpf_error("unknown host '%s'", name);
tproto = proto;
if (off_linktype == (u_int)-1 && tproto == Q_DEFAULT)
tproto = Q_IP;
b = gen_host(**alist++, 0xffffffff, tproto, dir, q.addr);
while (*alist) {
tmp = gen_host(**alist++, 0xffffffff,
tproto, dir, q.addr);
gen_or(b, tmp);
b = tmp;
}
return b;
#else
memset(&mask128, 0xff, sizeof(mask128));
res0 = res = pcap_nametoaddrinfo(name);
if (res == NULL)
bpf_error("unknown host '%s'", name);
ai = res;
b = tmp = NULL;
tproto = tproto6 = proto;
if (off_linktype == -1 && tproto == Q_DEFAULT) {
tproto = Q_IP;
tproto6 = Q_IPV6;
}
for (res = res0; res; res = res->ai_next) {
switch (res->ai_family) {
case AF_INET:
if (tproto == Q_IPV6)
continue;
sin4 = (struct sockaddr_in *)
res->ai_addr;
tmp = gen_host(ntohl(sin4->sin_addr.s_addr),
0xffffffff, tproto, dir, q.addr);
break;
case AF_INET6:
if (tproto6 == Q_IP)
continue;
sin6 = (struct sockaddr_in6 *)
res->ai_addr;
tmp = gen_host6(&sin6->sin6_addr,
&mask128, tproto6, dir, q.addr);
break;
default:
continue;
}
if (b)
gen_or(b, tmp);
b = tmp;
}
ai = NULL;
freeaddrinfo(res0);
if (b == NULL) {
bpf_error("unknown host '%s'%s", name,
(proto == Q_DEFAULT)
? ""
: " for specified address family");
}
return b;
#endif /*INET6*/
}
case Q_PORT:
if (proto != Q_DEFAULT &&
proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
bpf_error("illegal qualifier of 'port'");
if (pcap_nametoport(name, &port, &real_proto) == 0)
bpf_error("unknown port '%s'", name);
if (proto == Q_UDP) {
if (real_proto == IPPROTO_TCP)
bpf_error("port '%s' is tcp", name);
else if (real_proto == IPPROTO_SCTP)
bpf_error("port '%s' is sctp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_UDP;
}
if (proto == Q_TCP) {
if (real_proto == IPPROTO_UDP)
bpf_error("port '%s' is udp", name);
else if (real_proto == IPPROTO_SCTP)
bpf_error("port '%s' is sctp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_TCP;
}
if (proto == Q_SCTP) {
if (real_proto == IPPROTO_UDP)
bpf_error("port '%s' is udp", name);
else if (real_proto == IPPROTO_TCP)
bpf_error("port '%s' is tcp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_SCTP;
}
if (port < 0)
bpf_error("illegal port number %d < 0", port);
if (port > 65535)
bpf_error("illegal port number %d > 65535", port);
b = gen_port(port, real_proto, dir);
gen_or(gen_port6(port, real_proto, dir), b);
return b;
case Q_PORTRANGE:
if (proto != Q_DEFAULT &&
proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
bpf_error("illegal qualifier of 'portrange'");
if (pcap_nametoportrange(name, &port1, &port2, &real_proto) == 0)
bpf_error("unknown port in range '%s'", name);
if (proto == Q_UDP) {
if (real_proto == IPPROTO_TCP)
bpf_error("port in range '%s' is tcp", name);
else if (real_proto == IPPROTO_SCTP)
bpf_error("port in range '%s' is sctp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_UDP;
}
if (proto == Q_TCP) {
if (real_proto == IPPROTO_UDP)
bpf_error("port in range '%s' is udp", name);
else if (real_proto == IPPROTO_SCTP)
bpf_error("port in range '%s' is sctp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_TCP;
}
if (proto == Q_SCTP) {
if (real_proto == IPPROTO_UDP)
bpf_error("port in range '%s' is udp", name);
else if (real_proto == IPPROTO_TCP)
bpf_error("port in range '%s' is tcp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_SCTP;
}
if (port1 < 0)
bpf_error("illegal port number %d < 0", port1);
if (port1 > 65535)
bpf_error("illegal port number %d > 65535", port1);
if (port2 < 0)
bpf_error("illegal port number %d < 0", port2);
if (port2 > 65535)
bpf_error("illegal port number %d > 65535", port2);
b = gen_portrange(port1, port2, real_proto, dir);
gen_or(gen_portrange6(port1, port2, real_proto, dir), b);
return b;
case Q_GATEWAY:
#ifndef INET6
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error("unknown ether host: %s", name);
alist = pcap_nametoaddr(name);
if (alist == NULL || *alist == NULL)
bpf_error("unknown host '%s'", name);
b = gen_gateway(eaddr, alist, proto, dir);
free(eaddr);
return b;
#else
bpf_error("'gateway' not supported in this configuration");
#endif /*INET6*/
case Q_PROTO:
real_proto = lookup_proto(name, proto);
if (real_proto >= 0)
return gen_proto(real_proto, proto, dir);
else
bpf_error("unknown protocol: %s", name);
case Q_PROTOCHAIN:
real_proto = lookup_proto(name, proto);
if (real_proto >= 0)
return gen_protochain(real_proto, proto, dir);
else
bpf_error("unknown protocol: %s", name);
case Q_UNDEF:
syntax();
/* NOTREACHED */
}
abort();
/* NOTREACHED */
}
struct block *
gen_mcode(s1, s2, masklen, q)
register const char *s1, *s2;
register int masklen;
struct qual q;
{
register int nlen, mlen;
bpf_u_int32 n, m;
nlen = __pcap_atoin(s1, &n);
/* Promote short ipaddr */
n <<= 32 - nlen;
if (s2 != NULL) {
mlen = __pcap_atoin(s2, &m);
/* Promote short ipaddr */
m <<= 32 - mlen;
if ((n & ~m) != 0)
bpf_error("non-network bits set in \"%s mask %s\"",
s1, s2);
} else {
/* Convert mask len to mask */
if (masklen > 32)
bpf_error("mask length must be <= 32");
if (masklen == 0) {
/*
* X << 32 is not guaranteed by C to be 0; it's
* undefined.
*/
m = 0;
} else
m = 0xffffffff << (32 - masklen);
if ((n & ~m) != 0)
bpf_error("non-network bits set in \"%s/%d\"",
s1, masklen);
}
switch (q.addr) {
case Q_NET:
return gen_host(n, m, q.proto, q.dir, q.addr);
default:
bpf_error("Mask syntax for networks only");
/* NOTREACHED */
}
/* NOTREACHED */
return NULL;
}
struct block *
gen_ncode(s, v, q)
register const char *s;
bpf_u_int32 v;
struct qual q;
{
bpf_u_int32 mask;
int proto = q.proto;
int dir = q.dir;
register int vlen;
if (s == NULL)
vlen = 32;
else if (q.proto == Q_DECNET)
vlen = __pcap_atodn(s, &v);
else
vlen = __pcap_atoin(s, &v);
switch (q.addr) {
case Q_DEFAULT:
case Q_HOST:
case Q_NET:
if (proto == Q_DECNET)
return gen_host(v, 0, proto, dir, q.addr);
else if (proto == Q_LINK) {
bpf_error("illegal link layer address");
} else {
mask = 0xffffffff;
if (s == NULL && q.addr == Q_NET) {
/* Promote short net number */
while (v && (v & 0xff000000) == 0) {
v <<= 8;
mask <<= 8;
}
} else {
/* Promote short ipaddr */
v <<= 32 - vlen;
mask <<= 32 - vlen;
}
return gen_host(v, mask, proto, dir, q.addr);
}
case Q_PORT:
if (proto == Q_UDP)
proto = IPPROTO_UDP;
else if (proto == Q_TCP)
proto = IPPROTO_TCP;
else if (proto == Q_SCTP)
proto = IPPROTO_SCTP;
else if (proto == Q_DEFAULT)
proto = PROTO_UNDEF;
else
bpf_error("illegal qualifier of 'port'");
if (v > 65535)
bpf_error("illegal port number %u > 65535", v);
{
struct block *b;
b = gen_port((int)v, proto, dir);
gen_or(gen_port6((int)v, proto, dir), b);
return b;
}
case Q_PORTRANGE:
if (proto == Q_UDP)
proto = IPPROTO_UDP;
else if (proto == Q_TCP)
proto = IPPROTO_TCP;
else if (proto == Q_SCTP)
proto = IPPROTO_SCTP;
else if (proto == Q_DEFAULT)
proto = PROTO_UNDEF;
else
bpf_error("illegal qualifier of 'portrange'");
if (v > 65535)
bpf_error("illegal port number %u > 65535", v);
{
struct block *b;
b = gen_portrange((int)v, (int)v, proto, dir);
gen_or(gen_portrange6((int)v, (int)v, proto, dir), b);
return b;
}
case Q_GATEWAY:
bpf_error("'gateway' requires a name");
/* NOTREACHED */
case Q_PROTO:
return gen_proto((int)v, proto, dir);
case Q_PROTOCHAIN:
return gen_protochain((int)v, proto, dir);
case Q_UNDEF:
syntax();
/* NOTREACHED */
default:
abort();
/* NOTREACHED */
}
/* NOTREACHED */
}
#ifdef INET6
struct block *
gen_mcode6(s1, s2, masklen, q)
register const char *s1, *s2;
register int masklen;
struct qual q;
{
struct addrinfo *res;
struct in6_addr *addr;
struct in6_addr mask;
struct block *b;
u_int32_t *a, *m;
if (s2)
bpf_error("no mask %s supported", s2);
res = pcap_nametoaddrinfo(s1);
if (!res)
bpf_error("invalid ip6 address %s", s1);
ai = res;
if (res->ai_next)
bpf_error("%s resolved to multiple address", s1);
addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
if (sizeof(mask) * 8 < masklen)
bpf_error("mask length must be <= %u", (unsigned int)(sizeof(mask) * 8));
memset(&mask, 0, sizeof(mask));
memset(&mask, 0xff, masklen / 8);
if (masklen % 8) {
mask.s6_addr[masklen / 8] =
(0xff << (8 - masklen % 8)) & 0xff;
}
a = (u_int32_t *)addr;
m = (u_int32_t *)&mask;
if ((a[0] & ~m[0]) || (a[1] & ~m[1])
|| (a[2] & ~m[2]) || (a[3] & ~m[3])) {
bpf_error("non-network bits set in \"%s/%d\"", s1, masklen);
}
switch (q.addr) {
case Q_DEFAULT:
case Q_HOST:
if (masklen != 128)
bpf_error("Mask syntax for networks only");
/* FALLTHROUGH */
case Q_NET:
b = gen_host6(addr, &mask, q.proto, q.dir, q.addr);
ai = NULL;
freeaddrinfo(res);
return b;
default:
bpf_error("invalid qualifier against IPv6 address");
/* NOTREACHED */
}
return NULL;
}
#endif /*INET6*/
struct block *
gen_ecode(eaddr, q)
register const u_char *eaddr;
struct qual q;
{
struct block *b, *tmp;
if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
switch (linktype) {
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
return gen_ehostop(eaddr, (int)q.dir);
case DLT_FDDI:
return gen_fhostop(eaddr, (int)q.dir);
case DLT_IEEE802:
return gen_thostop(eaddr, (int)q.dir);
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
return gen_wlanhostop(eaddr, (int)q.dir);
case DLT_SUNATM:
if (is_lane) {
/*
* Check that the packet doesn't begin with an
* LE Control marker. (We've already generated
* a test for LANE.)
*/
tmp = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H,
0xFF00);
gen_not(tmp);
/*
* Now check the MAC address.
*/
b = gen_ehostop(eaddr, (int)q.dir);
gen_and(tmp, b);
return b;
}
break;
case DLT_IP_OVER_FC:
return gen_ipfchostop(eaddr, (int)q.dir);
default:
bpf_error("ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
break;
}
}
bpf_error("ethernet address used in non-ether expression");
/* NOTREACHED */
return NULL;
}
void
sappend(s0, s1)
struct slist *s0, *s1;
{
/*
* This is definitely not the best way to do this, but the
* lists will rarely get long.
*/
while (s0->next)
s0 = s0->next;
s0->next = s1;
}
static struct slist *
xfer_to_x(a)
struct arth *a;
{
struct slist *s;
s = new_stmt(BPF_LDX|BPF_MEM);
s->s.k = a->regno;
return s;
}
static struct slist *
xfer_to_a(a)
struct arth *a;
{
struct slist *s;
s = new_stmt(BPF_LD|BPF_MEM);
s->s.k = a->regno;
return s;
}
/*
* Modify "index" to use the value stored into its register as an
* offset relative to the beginning of the header for the protocol
* "proto", and allocate a register and put an item "size" bytes long
* (1, 2, or 4) at that offset into that register, making it the register
* for "index".
*/
struct arth *
gen_load(proto, inst, size)
int proto;
struct arth *inst;
int size;
{
struct slist *s, *tmp;
struct block *b;
int regno = alloc_reg();
free_reg(inst->regno);
switch (size) {
default:
bpf_error("data size must be 1, 2, or 4");
case 1:
size = BPF_B;
break;
case 2:
size = BPF_H;
break;
case 4:
size = BPF_W;
break;
}
switch (proto) {
default:
bpf_error("unsupported index operation");
case Q_RADIO:
/*
* The offset is relative to the beginning of the packet
* data, if we have a radio header. (If we don't, this
* is an error.)
*/
if (linktype != DLT_IEEE802_11_RADIO_AVS &&
linktype != DLT_IEEE802_11_RADIO &&
linktype != DLT_PRISM_HEADER)
bpf_error("radio information not present in capture");
/*
* Load into the X register the offset computed into the
* register specified by "index".
*/
s = xfer_to_x(inst);
/*
* Load the item at that offset.
*/
tmp = new_stmt(BPF_LD|BPF_IND|size);
sappend(s, tmp);
sappend(inst->s, s);
break;
case Q_LINK:
/*
* The offset is relative to the beginning of
* the link-layer header.
*
* XXX - what about ATM LANE? Should the index be
* relative to the beginning of the AAL5 frame, so
* that 0 refers to the beginning of the LE Control
* field, or relative to the beginning of the LAN
* frame, so that 0 refers, for Ethernet LANE, to
* the beginning of the destination address?
*/
s = gen_llprefixlen();
/*
* If "s" is non-null, it has code to arrange that the
* X register contains the length of the prefix preceding
* the link-layer header. Add to it the offset computed
* into the register specified by "index", and move that
* into the X register. Otherwise, just load into the X
* register the offset computed into the register specified
* by "index".
*/
if (s != NULL) {
sappend(s, xfer_to_a(inst));
sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(BPF_MISC|BPF_TAX));
} else
s = xfer_to_x(inst);
/*
* Load the item at the sum of the offset we've put in the
* X register and the offset of the start of the link
* layer header (which is 0 if the radio header is
* variable-length; that header length is what we put
* into the X register and then added to the index).
*/
tmp = new_stmt(BPF_LD|BPF_IND|size);
tmp->s.k = off_ll;
sappend(s, tmp);
sappend(inst->s, s);
break;
case Q_IP:
case Q_ARP:
case Q_RARP:
case Q_ATALK:
case Q_DECNET:
case Q_SCA:
case Q_LAT:
case Q_MOPRC:
case Q_MOPDL:
case Q_IPV6:
/*
* The offset is relative to the beginning of
* the network-layer header.
* XXX - are there any cases where we want
* off_nl_nosnap?
*/
s = gen_off_macpl();
/*
* If "s" is non-null, it has code to arrange that the
* X register contains the offset of the MAC-layer
* payload. Add to it the offset computed into the
* register specified by "index", and move that into
* the X register. Otherwise, just load into the X
* register the offset computed into the register specified
* by "index".
*/
if (s != NULL) {
sappend(s, xfer_to_a(inst));
sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(BPF_MISC|BPF_TAX));
} else
s = xfer_to_x(inst);
/*
* Load the item at the sum of the offset we've put in the
* X register, the offset of the start of the network
* layer header from the beginning of the MAC-layer
* payload, and the purported offset of the start of the
* MAC-layer payload (which might be 0 if there's a
* variable-length prefix before the link-layer header
* or the link-layer header itself is variable-length;
* the variable-length offset of the start of the
* MAC-layer payload is what we put into the X register
* and then added to the index).
*/
tmp = new_stmt(BPF_LD|BPF_IND|size);
tmp->s.k = off_macpl + off_nl;
sappend(s, tmp);
sappend(inst->s, s);
/*
* Do the computation only if the packet contains
* the protocol in question.
*/
b = gen_proto_abbrev(proto);
if (inst->b)
gen_and(inst->b, b);
inst->b = b;
break;
case Q_SCTP:
case Q_TCP:
case Q_UDP:
case Q_ICMP:
case Q_IGMP:
case Q_IGRP:
case Q_PIM:
case Q_VRRP:
case Q_CARP:
/*
* The offset is relative to the beginning of
* the transport-layer header.
*
* Load the X register with the length of the IPv4 header
* (plus the offset of the link-layer header, if it's
* a variable-length header), in bytes.
*
* XXX - are there any cases where we want
* off_nl_nosnap?
* XXX - we should, if we're built with
* IPv6 support, generate code to load either
* IPv4, IPv6, or both, as appropriate.
*/
s = gen_loadx_iphdrlen();
/*
* The X register now contains the sum of the length
* of any variable-length header preceding the link-layer
* header, any variable-length link-layer header, and the
* length of the network-layer header.
*
* Load into the A register the offset relative to
* the beginning of the transport layer header,
* add the X register to that, move that to the
* X register, and load with an offset from the
* X register equal to the offset of the network
* layer header relative to the beginning of
* the MAC-layer payload plus the fixed-length
* portion of the offset of the MAC-layer payload
* from the beginning of the raw packet data.
*/
sappend(s, xfer_to_a(inst));
sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(BPF_MISC|BPF_TAX));
sappend(s, tmp = new_stmt(BPF_LD|BPF_IND|size));
tmp->s.k = off_macpl + off_nl;
sappend(inst->s, s);
/*
* Do the computation only if the packet contains
* the protocol in question - which is true only
* if this is an IP datagram and is the first or
* only fragment of that datagram.
*/
gen_and(gen_proto_abbrev(proto), b = gen_ipfrag());
if (inst->b)
gen_and(inst->b, b);
gen_and(gen_proto_abbrev(Q_IP), b);
inst->b = b;
break;
case Q_ICMPV6:
bpf_error("IPv6 upper-layer protocol is not supported by proto[x]");
/*NOTREACHED*/
}
inst->regno = regno;
s = new_stmt(BPF_ST);
s->s.k = regno;
sappend(inst->s, s);
return inst;
}
struct block *
gen_relation(code, a0, a1, reversed)
int code;
struct arth *a0, *a1;
int reversed;
{
struct slist *s0, *s1, *s2;
struct block *b, *tmp;
s0 = xfer_to_x(a1);
s1 = xfer_to_a(a0);
if (code == BPF_JEQ) {
s2 = new_stmt(BPF_ALU|BPF_SUB|BPF_X);
b = new_block(JMP(code));
sappend(s1, s2);
}
else
b = new_block(BPF_JMP|code|BPF_X);
if (reversed)
gen_not(b);
sappend(s0, s1);
sappend(a1->s, s0);
sappend(a0->s, a1->s);
b->stmts = a0->s;
free_reg(a0->regno);
free_reg(a1->regno);
/* 'and' together protocol checks */
if (a0->b) {
if (a1->b) {
gen_and(a0->b, tmp = a1->b);
}
else
tmp = a0->b;
} else
tmp = a1->b;
if (tmp)
gen_and(tmp, b);
return b;
}
struct arth *
gen_loadlen()
{
int regno = alloc_reg();
struct arth *a = (struct arth *)newchunk(sizeof(*a));
struct slist *s;
s = new_stmt(BPF_LD|BPF_LEN);
s->next = new_stmt(BPF_ST);
s->next->s.k = regno;
a->s = s;
a->regno = regno;
return a;
}
struct arth *
gen_loadi(val)
int val;
{
struct arth *a;
struct slist *s;
int reg;
a = (struct arth *)newchunk(sizeof(*a));
reg = alloc_reg();
s = new_stmt(BPF_LD|BPF_IMM);
s->s.k = val;
s->next = new_stmt(BPF_ST);
s->next->s.k = reg;
a->s = s;
a->regno = reg;
return a;
}
struct arth *
gen_neg(a)
struct arth *a;
{
struct slist *s;
s = xfer_to_a(a);
sappend(a->s, s);
s = new_stmt(BPF_ALU|BPF_NEG);
s->s.k = 0;
sappend(a->s, s);
s = new_stmt(BPF_ST);
s->s.k = a->regno;
sappend(a->s, s);
return a;
}
struct arth *
gen_arth(code, a0, a1)
int code;
struct arth *a0, *a1;
{
struct slist *s0, *s1, *s2;
s0 = xfer_to_x(a1);
s1 = xfer_to_a(a0);
s2 = new_stmt(BPF_ALU|BPF_X|code);
sappend(s1, s2);
sappend(s0, s1);
sappend(a1->s, s0);
sappend(a0->s, a1->s);
free_reg(a0->regno);
free_reg(a1->regno);
s0 = new_stmt(BPF_ST);
a0->regno = s0->s.k = alloc_reg();
sappend(a0->s, s0);
return a0;
}
/*
* Here we handle simple allocation of the scratch registers.
* If too many registers are alloc'd, the allocator punts.
*/
static int regused[BPF_MEMWORDS];
static int curreg;
/*
* Initialize the table of used registers and the current register.
*/
static void
init_regs()
{
curreg = 0;
memset(regused, 0, sizeof regused);
}
/*
* Return the next free register.
*/
static int
alloc_reg()
{
int n = BPF_MEMWORDS;
while (--n >= 0) {
if (regused[curreg])
curreg = (curreg + 1) % BPF_MEMWORDS;
else {
regused[curreg] = 1;
return curreg;
}
}
bpf_error("too many registers needed to evaluate expression");
/* NOTREACHED */
return 0;
}
/*
* Return a register to the table so it can
* be used later.
*/
static void
free_reg(n)
int n;
{
regused[n] = 0;
}
static struct block *
gen_len(jmp, n)
int jmp, n;
{
struct slist *s;
struct block *b;
s = new_stmt(BPF_LD|BPF_LEN);
b = new_block(JMP(jmp));
b->stmts = s;
b->s.k = n;
return b;
}
struct block *
gen_greater(n)
int n;
{
return gen_len(BPF_JGE, n);
}
/*
* Actually, this is less than or equal.
*/
struct block *
gen_less(n)
int n;
{
struct block *b;
b = gen_len(BPF_JGT, n);
gen_not(b);
return b;
}
/*
* This is for "byte {idx} {op} {val}"; "idx" is treated as relative to
* the beginning of the link-layer header.
* XXX - that means you can't test values in the radiotap header, but
* as that header is difficult if not impossible to parse generally
* without a loop, that might not be a severe problem. A new keyword
* "radio" could be added for that, although what you'd really want
* would be a way of testing particular radio header values, which
* would generate code appropriate to the radio header in question.
*/
struct block *
gen_byteop(op, idx, val)
int op, idx, val;
{
struct block *b;
struct slist *s;
switch (op) {
default:
abort();
case '=':
return gen_cmp(OR_LINK, (u_int)idx, BPF_B, (bpf_int32)val);
case '<':
b = gen_cmp_lt(OR_LINK, (u_int)idx, BPF_B, (bpf_int32)val);
return b;
case '>':
b = gen_cmp_gt(OR_LINK, (u_int)idx, BPF_B, (bpf_int32)val);
return b;
case '|':
s = new_stmt(BPF_ALU|BPF_OR|BPF_K);
break;
case '&':
s = new_stmt(BPF_ALU|BPF_AND|BPF_K);
break;
}
s->s.k = val;
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
gen_not(b);
return b;
}
static u_char abroadcast[] = { 0x0 };
struct block *
gen_broadcast(proto)
int proto;
{
bpf_u_int32 hostmask;
struct block *b0, *b1, *b2;
static u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
switch (proto) {
case Q_DEFAULT:
case Q_LINK:
switch (linktype) {
case DLT_ARCNET:
case DLT_ARCNET_LINUX:
return gen_ahostop(abroadcast, Q_DST);
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
return gen_ehostop(ebroadcast, Q_DST);
case DLT_FDDI:
return gen_fhostop(ebroadcast, Q_DST);
case DLT_IEEE802:
return gen_thostop(ebroadcast, Q_DST);
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
return gen_wlanhostop(ebroadcast, Q_DST);
case DLT_IP_OVER_FC:
return gen_ipfchostop(ebroadcast, Q_DST);
case DLT_SUNATM:
if (is_lane) {
/*
* Check that the packet doesn't begin with an
* LE Control marker. (We've already generated
* a test for LANE.)
*/
b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS,
BPF_H, 0xFF00);
gen_not(b1);
/*
* Now check the MAC address.
*/
b0 = gen_ehostop(ebroadcast, Q_DST);
gen_and(b1, b0);
return b0;
}
break;
default:
bpf_error("not a broadcast link");
}
break;
case Q_IP:
/*
* We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff)
* as an indication that we don't know the netmask, and fail
* in that case.
*/
if (netmask == PCAP_NETMASK_UNKNOWN)
bpf_error("netmask not known, so 'ip broadcast' not supported");
b0 = gen_linktype(ETHERTYPE_IP);
hostmask = ~netmask;
b1 = gen_mcmp(OR_NET, 16, BPF_W, (bpf_int32)0, hostmask);
b2 = gen_mcmp(OR_NET, 16, BPF_W,
(bpf_int32)(~0 & hostmask), hostmask);
gen_or(b1, b2);
gen_and(b0, b2);
return b2;
}
bpf_error("only link-layer/IP broadcast filters supported");
/* NOTREACHED */
return NULL;
}
/*
* Generate code to test the low-order bit of a MAC address (that's
* the bottom bit of the *first* byte).
*/
static struct block *
gen_mac_multicast(offset)
int offset;
{
register struct block *b0;
register struct slist *s;
/* link[offset] & 1 != 0 */
s = gen_load_a(OR_LINK, offset, BPF_B);
b0 = new_block(JMP(BPF_JSET));
b0->s.k = 1;
b0->stmts = s;
return b0;
}
struct block *
gen_multicast(proto)
int proto;
{
register struct block *b0, *b1, *b2;
register struct slist *s;
switch (proto) {
case Q_DEFAULT:
case Q_LINK:
switch (linktype) {
case DLT_ARCNET:
case DLT_ARCNET_LINUX:
/* all ARCnet multicasts use the same address */
return gen_ahostop(abroadcast, Q_DST);
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
/* ether[0] & 1 != 0 */
return gen_mac_multicast(0);
case DLT_FDDI:
/*
* XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX
*
* XXX - was that referring to bit-order issues?
*/
/* fddi[1] & 1 != 0 */
return gen_mac_multicast(1);
case DLT_IEEE802:
/* tr[2] & 1 != 0 */
return gen_mac_multicast(2);
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
case DLT_PPI:
/*
* Oh, yuk.
*
* For control frames, there is no DA.
*
* For management frames, DA is at an
* offset of 4 from the beginning of
* the packet.
*
* For data frames, DA is at an offset
* of 4 from the beginning of the packet
* if To DS is clear and at an offset of
* 16 from the beginning of the packet
* if To DS is set.
*/
/*
* Generate the tests to be done for data frames.
*
* First, check for To DS set, i.e. "link[1] & 0x01".
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x01; /* To DS */
b1->stmts = s;
/*
* If To DS is set, the DA is at 16.
*/
b0 = gen_mac_multicast(16);
gen_and(b1, b0);
/*
* Now, check for To DS not set, i.e. check
* "!(link[1] & 0x01)".
*/
s = gen_load_a(OR_LINK, 1, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x01; /* To DS */
b2->stmts = s;
gen_not(b2);
/*
* If To DS is not set, the DA is at 4.
*/
b1 = gen_mac_multicast(4);
gen_and(b2, b1);
/*
* Now OR together the last two checks. That gives
* the complete set of checks for data frames.
*/
gen_or(b1, b0);
/*
* Now check for a data frame.
* I.e, check "link[0] & 0x08".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x08;
b1->stmts = s;
/*
* AND that with the checks done for data frames.
*/
gen_and(b1, b0);
/*
* If the high-order bit of the type value is 0, this
* is a management frame.
* I.e, check "!(link[0] & 0x08)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b2 = new_block(JMP(BPF_JSET));
b2->s.k = 0x08;
b2->stmts = s;
gen_not(b2);
/*
* For management frames, the DA is at 4.
*/
b1 = gen_mac_multicast(4);
gen_and(b2, b1);
/*
* OR that with the checks done for data frames.
* That gives the checks done for management and
* data frames.
*/
gen_or(b1, b0);
/*
* If the low-order bit of the type value is 1,
* this is either a control frame or a frame
* with a reserved type, and thus not a
* frame with an SA.
*
* I.e., check "!(link[0] & 0x04)".
*/
s = gen_load_a(OR_LINK, 0, BPF_B);
b1 = new_block(JMP(BPF_JSET));
b1->s.k = 0x04;
b1->stmts = s;
gen_not(b1);
/*
* AND that with the checks for data and management
* frames.
*/
gen_and(b1, b0);
return b0;
case DLT_IP_OVER_FC:
b0 = gen_mac_multicast(2);
return b0;
case DLT_SUNATM:
if (is_lane) {
/*
* Check that the packet doesn't begin with an
* LE Control marker. (We've already generated
* a test for LANE.)
*/
b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS,
BPF_H, 0xFF00);
gen_not(b1);
/* ether[off_mac] & 1 != 0 */
b0 = gen_mac_multicast(off_mac);
gen_and(b1, b0);
return b0;
}
break;
default:
break;
}
/* Link not known to support multicasts */
break;
case Q_IP:
b0 = gen_linktype(ETHERTYPE_IP);
b1 = gen_cmp_ge(OR_NET, 16, BPF_B, (bpf_int32)224);
gen_and(b0, b1);
return b1;
case Q_IPV6:
b0 = gen_linktype(ETHERTYPE_IPV6);
b1 = gen_cmp(OR_NET, 24, BPF_B, (bpf_int32)255);
gen_and(b0, b1);
return b1;
}
bpf_error("link-layer multicast filters supported only on ethernet/FDDI/token ring/ARCNET/802.11/ATM LANE/Fibre Channel");
/* NOTREACHED */
return NULL;
}
/*
* Filter on inbound (dir == 0) or outbound (dir == 1) traffic.
* Outbound traffic is sent by this machine, while inbound traffic is
* sent by a remote machine (and may include packets destined for a
* unicast or multicast link-layer address we are not subscribing to).
* These are the same definitions implemented by pcap_setdirection().
* Capturing only unicast traffic destined for this host is probably
* better accomplished using a higher-layer filter.
*/
struct block *
gen_inbound(dir)
int dir;
{
register struct block *b0;
/*
* Only some data link types support inbound/outbound qualifiers.
*/
switch (linktype) {
case DLT_SLIP:
b0 = gen_relation(BPF_JEQ,
gen_load(Q_LINK, gen_loadi(0), 1),
gen_loadi(0),
dir);
break;
case DLT_IPNET:
if (dir) {
/* match outgoing packets */
b0 = gen_cmp(OR_LINK, 2, BPF_H, IPNET_OUTBOUND);
} else {
/* match incoming packets */
b0 = gen_cmp(OR_LINK, 2, BPF_H, IPNET_INBOUND);
}
break;
case DLT_LINUX_SLL:
/* match outgoing packets */
b0 = gen_cmp(OR_LINK, 0, BPF_H, LINUX_SLL_OUTGOING);
if (!dir) {
/* to filter on inbound traffic, invert the match */
gen_not(b0);
}
break;
#ifdef HAVE_NET_PFVAR_H
case DLT_PFLOG:
b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, dir), BPF_B,
(bpf_int32)((dir == 0) ? PF_IN : PF_OUT));
break;
#endif
case DLT_PPP_PPPD:
if (dir) {
/* match outgoing packets */
b0 = gen_cmp(OR_LINK, 0, BPF_B, PPP_PPPD_OUT);
} else {
/* match incoming packets */
b0 = gen_cmp(OR_LINK, 0, BPF_B, PPP_PPPD_IN);
}
break;
case DLT_JUNIPER_MFR:
case DLT_JUNIPER_MLFR:
case DLT_JUNIPER_MLPPP:
case DLT_JUNIPER_ATM1:
case DLT_JUNIPER_ATM2:
case DLT_JUNIPER_PPPOE:
case DLT_JUNIPER_PPPOE_ATM:
case DLT_JUNIPER_GGSN:
case DLT_JUNIPER_ES:
case DLT_JUNIPER_MONITOR:
case DLT_JUNIPER_SERVICES:
case DLT_JUNIPER_ETHER:
case DLT_JUNIPER_PPP:
case DLT_JUNIPER_FRELAY:
case DLT_JUNIPER_CHDLC:
case DLT_JUNIPER_VP:
case DLT_JUNIPER_ST:
case DLT_JUNIPER_ISM:
case DLT_JUNIPER_VS:
case DLT_JUNIPER_SRX_E2E:
case DLT_JUNIPER_FIBRECHANNEL:
case DLT_JUNIPER_ATM_CEMIC:
/* juniper flags (including direction) are stored
* the byte after the 3-byte magic number */
if (dir) {
/* match outgoing packets */
b0 = gen_mcmp(OR_LINK, 3, BPF_B, 0, 0x01);
} else {
/* match incoming packets */
b0 = gen_mcmp(OR_LINK, 3, BPF_B, 1, 0x01);
}
break;
default:
/*
* If we have packet meta-data indicating a direction,
* check it, otherwise give up as this link-layer type
* has nothing in the packet data.
*/
#if defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
/*
* We infer that this is Linux with PF_PACKET support.
* If this is a *live* capture, we can look at
* special meta-data in the filter expression;
* if it's a savefile, we can't.
*/
if (bpf_pcap->sf.rfile != NULL) {
/* We have a FILE *, so this is a savefile */
bpf_error("inbound/outbound not supported on linktype %d when reading savefiles",
linktype);
b0 = NULL;
/* NOTREACHED */
}
/* match outgoing packets */
b0 = gen_cmp(OR_LINK, SKF_AD_OFF + SKF_AD_PKTTYPE, BPF_H,
PACKET_OUTGOING);
if (!dir) {
/* to filter on inbound traffic, invert the match */
gen_not(b0);
}
#else /* defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
bpf_error("inbound/outbound not supported on linktype %d",
linktype);
b0 = NULL;
/* NOTREACHED */
#endif /* defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
}
return (b0);
}
#ifdef HAVE_NET_PFVAR_H
/* PF firewall log matched interface */
struct block *
gen_pf_ifname(const char *ifname)
{
struct block *b0;
u_int len, off;
if (linktype != DLT_PFLOG) {
bpf_error("ifname supported only on PF linktype");
/* NOTREACHED */
}
len = sizeof(((struct pfloghdr *)0)->ifname);
off = offsetof(struct pfloghdr, ifname);
if (strlen(ifname) >= len) {
bpf_error("ifname interface names can only be %d characters",
len-1);
/* NOTREACHED */
}
b0 = gen_bcmp(OR_LINK, off, strlen(ifname), (const u_char *)ifname);
return (b0);
}
/* PF firewall log ruleset name */
struct block *
gen_pf_ruleset(char *ruleset)
{
struct block *b0;
if (linktype != DLT_PFLOG) {
bpf_error("ruleset supported only on PF linktype");
/* NOTREACHED */
}
if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) {
bpf_error("ruleset names can only be %ld characters",
(long)(sizeof(((struct pfloghdr *)0)->ruleset) - 1));
/* NOTREACHED */
}
b0 = gen_bcmp(OR_LINK, offsetof(struct pfloghdr, ruleset),
strlen(ruleset), (const u_char *)ruleset);
return (b0);
}
/* PF firewall log rule number */
struct block *
gen_pf_rnr(int rnr)
{
struct block *b0;
if (linktype != DLT_PFLOG) {
bpf_error("rnr supported only on PF linktype");
/* NOTREACHED */
}
b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, rulenr), BPF_W,
(bpf_int32)rnr);
return (b0);
}
/* PF firewall log sub-rule number */
struct block *
gen_pf_srnr(int srnr)
{
struct block *b0;
if (linktype != DLT_PFLOG) {
bpf_error("srnr supported only on PF linktype");
/* NOTREACHED */
}
b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, subrulenr), BPF_W,
(bpf_int32)srnr);
return (b0);
}
/* PF firewall log reason code */
struct block *
gen_pf_reason(int reason)
{
struct block *b0;
if (linktype != DLT_PFLOG) {
bpf_error("reason supported only on PF linktype");
/* NOTREACHED */
}
b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, reason), BPF_B,
(bpf_int32)reason);
return (b0);
}
/* PF firewall log action */
struct block *
gen_pf_action(int action)
{
struct block *b0;
if (linktype != DLT_PFLOG) {
bpf_error("action supported only on PF linktype");
/* NOTREACHED */
}
b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, action), BPF_B,
(bpf_int32)action);
return (b0);
}
#else /* !HAVE_NET_PFVAR_H */
struct block *
gen_pf_ifname(const char *ifname)
{
bpf_error("libpcap was compiled without pf support");
/* NOTREACHED */
return (NULL);
}
struct block *
gen_pf_ruleset(char *ruleset)
{
bpf_error("libpcap was compiled on a machine without pf support");
/* NOTREACHED */
return (NULL);
}
struct block *
gen_pf_rnr(int rnr)
{
bpf_error("libpcap was compiled on a machine without pf support");
/* NOTREACHED */
return (NULL);
}
struct block *
gen_pf_srnr(int srnr)
{
bpf_error("libpcap was compiled on a machine without pf support");
/* NOTREACHED */
return (NULL);
}
struct block *
gen_pf_reason(int reason)
{
bpf_error("libpcap was compiled on a machine without pf support");
/* NOTREACHED */
return (NULL);
}
struct block *
gen_pf_action(int action)
{
bpf_error("libpcap was compiled on a machine without pf support");
/* NOTREACHED */
return (NULL);
}
#endif /* HAVE_NET_PFVAR_H */
/* IEEE 802.11 wireless header */
struct block *
gen_p80211_type(int type, int mask)
{
struct block *b0;
switch (linktype) {
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
b0 = gen_mcmp(OR_LINK, 0, BPF_B, (bpf_int32)type,
(bpf_int32)mask);
break;
default:
bpf_error("802.11 link-layer types supported only on 802.11");
/* NOTREACHED */
}
return (b0);
}
struct block *
gen_p80211_fcdir(int fcdir)
{
struct block *b0;
switch (linktype) {
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
case DLT_IEEE802_11_RADIO:
break;
default:
bpf_error("frame direction supported only with 802.11 headers");
/* NOTREACHED */
}
b0 = gen_mcmp(OR_LINK, 1, BPF_B, (bpf_int32)fcdir,
(bpf_u_int32)IEEE80211_FC1_DIR_MASK);
return (b0);
}
struct block *
gen_acode(eaddr, q)
register const u_char *eaddr;
struct qual q;
{
switch (linktype) {
case DLT_ARCNET:
case DLT_ARCNET_LINUX:
if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) &&
q.proto == Q_LINK)
return (gen_ahostop(eaddr, (int)q.dir));
else {
bpf_error("ARCnet address used in non-arc expression");
/* NOTREACHED */
}
break;
default:
bpf_error("aid supported only on ARCnet");
/* NOTREACHED */
}
bpf_error("ARCnet address used in non-arc expression");
/* NOTREACHED */
return NULL;
}
static struct block *
gen_ahostop(eaddr, dir)
register const u_char *eaddr;
register int dir;
{
register struct block *b0, *b1;
switch (dir) {
/* src comes first, different from Ethernet */
case Q_SRC:
return gen_bcmp(OR_LINK, 0, 1, eaddr);
case Q_DST:
return gen_bcmp(OR_LINK, 1, 1, eaddr);
case Q_AND:
b0 = gen_ahostop(eaddr, Q_SRC);
b1 = gen_ahostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_ahostop(eaddr, Q_SRC);
b1 = gen_ahostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
case Q_ADDR1:
bpf_error("'addr1' is only supported on 802.11");
break;
case Q_ADDR2:
bpf_error("'addr2' is only supported on 802.11");
break;
case Q_ADDR3:
bpf_error("'addr3' is only supported on 802.11");
break;
case Q_ADDR4:
bpf_error("'addr4' is only supported on 802.11");
break;
case Q_RA:
bpf_error("'ra' is only supported on 802.11");
break;
case Q_TA:
bpf_error("'ta' is only supported on 802.11");
break;
}
abort();
/* NOTREACHED */
}
/*
* support IEEE 802.1Q VLAN trunk over ethernet
*/
struct block *
gen_vlan(vlan_num)
int vlan_num;
{
struct block *b0, *b1;
/* can't check for VLAN-encapsulated packets inside MPLS */
if (label_stack_depth > 0)
bpf_error("no VLAN match after MPLS");
/*
* Check for a VLAN packet, and then change the offsets to point
* to the type and data fields within the VLAN packet. Just
* increment the offsets, so that we can support a hierarchy, e.g.
* "vlan 300 && vlan 200" to capture VLAN 200 encapsulated within
* VLAN 100.
*
* XXX - this is a bit of a kludge. If we were to split the
* compiler into a parser that parses an expression and
* generates an expression tree, and a code generator that
* takes an expression tree (which could come from our
* parser or from some other parser) and generates BPF code,
* we could perhaps make the offsets parameters of routines
* and, in the handler for an "AND" node, pass to subnodes
* other than the VLAN node the adjusted offsets.
*
* This would mean that "vlan" would, instead of changing the
* behavior of *all* tests after it, change only the behavior
* of tests ANDed with it. That would change the documented
* semantics of "vlan", which might break some expressions.
* However, it would mean that "(vlan and ip) or ip" would check
* both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
* checking only for VLAN-encapsulated IP, so that could still
* be considered worth doing; it wouldn't break expressions
* that are of the form "vlan and ..." or "vlan N and ...",
* which I suspect are the most common expressions involving
* "vlan". "vlan or ..." doesn't necessarily do what the user
* would really want, now, as all the "or ..." tests would
* be done assuming a VLAN, even though the "or" could be viewed
* as meaning "or, if this isn't a VLAN packet...".
*/
orig_nl = off_nl;
switch (linktype) {
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
/* check for VLAN, including QinQ */
b0 = gen_cmp(OR_LINK, off_linktype, BPF_H,
(bpf_int32)ETHERTYPE_8021Q);
b1 = gen_cmp(OR_LINK, off_linktype, BPF_H,
(bpf_int32)ETHERTYPE_8021QINQ);
gen_or(b0,b1);
b0 = b1;
/* If a specific VLAN is requested, check VLAN id */
if (vlan_num >= 0) {
b1 = gen_mcmp(OR_MACPL, 0, BPF_H,
(bpf_int32)vlan_num, 0x0fff);
gen_and(b0, b1);
b0 = b1;
}
off_macpl += 4;
off_linktype += 4;
#if 0
off_nl_nosnap += 4;
off_nl += 4;
#endif
break;
default:
bpf_error("no VLAN support for data link type %d",
linktype);
/*NOTREACHED*/
}
return (b0);
}
/*
* support for MPLS
*/
struct block *
gen_mpls(label_num)
int label_num;
{
struct block *b0,*b1;
/*
* Change the offsets to point to the type and data fields within
* the MPLS packet. Just increment the offsets, so that we
* can support a hierarchy, e.g. "mpls 100000 && mpls 1024" to
* capture packets with an outer label of 100000 and an inner
* label of 1024.
*
* XXX - this is a bit of a kludge. See comments in gen_vlan().
*/
orig_nl = off_nl;
if (label_stack_depth > 0) {
/* just match the bottom-of-stack bit clear */
b0 = gen_mcmp(OR_MACPL, orig_nl-2, BPF_B, 0, 0x01);
} else {
/*
* Indicate that we're checking MPLS-encapsulated headers,
* to make sure higher level code generators don't try to
* match against IP-related protocols such as Q_ARP, Q_RARP
* etc.
*/
switch (linktype) {
case DLT_C_HDLC: /* fall through */
case DLT_EN10MB:
case DLT_NETANALYZER:
case DLT_NETANALYZER_TRANSPARENT:
b0 = gen_linktype(ETHERTYPE_MPLS);
break;
case DLT_PPP:
b0 = gen_linktype(PPP_MPLS_UCAST);
break;
/* FIXME add other DLT_s ...
* for Frame-Relay/and ATM this may get messy due to SNAP headers
* leave it for now */
default:
bpf_error("no MPLS support for data link type %d",
linktype);
b0 = NULL;
/*NOTREACHED*/
break;
}
}
/* If a specific MPLS label is requested, check it */
if (label_num >= 0) {
label_num = label_num << 12; /* label is shifted 12 bits on the wire */
b1 = gen_mcmp(OR_MACPL, orig_nl, BPF_W, (bpf_int32)label_num,
0xfffff000); /* only compare the first 20 bits */
gen_and(b0, b1);
b0 = b1;
}
off_nl_nosnap += 4;
off_nl += 4;
label_stack_depth++;
return (b0);
}
/*
* Support PPPOE discovery and session.
*/
struct block *
gen_pppoed()
{
/* check for PPPoE discovery */
return gen_linktype((bpf_int32)ETHERTYPE_PPPOED);
}
struct block *
gen_pppoes()
{
struct block *b0;
/*
* Test against the PPPoE session link-layer type.
*/
b0 = gen_linktype((bpf_int32)ETHERTYPE_PPPOES);
/*
* Change the offsets to point to the type and data fields within
* the PPP packet, and note that this is PPPoE rather than
* raw PPP.
*
* XXX - this is a bit of a kludge. If we were to split the
* compiler into a parser that parses an expression and
* generates an expression tree, and a code generator that
* takes an expression tree (which could come from our
* parser or from some other parser) and generates BPF code,
* we could perhaps make the offsets parameters of routines
* and, in the handler for an "AND" node, pass to subnodes
* other than the PPPoE node the adjusted offsets.
*
* This would mean that "pppoes" would, instead of changing the
* behavior of *all* tests after it, change only the behavior
* of tests ANDed with it. That would change the documented
* semantics of "pppoes", which might break some expressions.
* However, it would mean that "(pppoes and ip) or ip" would check
* both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
* checking only for VLAN-encapsulated IP, so that could still
* be considered worth doing; it wouldn't break expressions
* that are of the form "pppoes and ..." which I suspect are the
* most common expressions involving "pppoes". "pppoes or ..."
* doesn't necessarily do what the user would really want, now,
* as all the "or ..." tests would be done assuming PPPoE, even
* though the "or" could be viewed as meaning "or, if this isn't
* a PPPoE packet...".
*/
orig_linktype = off_linktype; /* save original values */
orig_nl = off_nl;
is_pppoes = 1;
/*
* The "network-layer" protocol is PPPoE, which has a 6-byte
* PPPoE header, followed by a PPP packet.
*
* There is no HDLC encapsulation for the PPP packet (it's
* encapsulated in PPPoES instead), so the link-layer type
* starts at the first byte of the PPP packet. For PPPoE,
* that offset is relative to the beginning of the total
* link-layer payload, including any 802.2 LLC header, so
* it's 6 bytes past off_nl.
*/
off_linktype = off_nl + 6;
/*
* The network-layer offsets are relative to the beginning
* of the MAC-layer payload; that's past the 6-byte
* PPPoE header and the 2-byte PPP header.
*/
off_nl = 6+2;
off_nl_nosnap = 6+2;
return b0;
}
struct block *
gen_atmfield_code(atmfield, jvalue, jtype, reverse)
int atmfield;
bpf_int32 jvalue;
bpf_u_int32 jtype;
int reverse;
{
struct block *b0;
switch (atmfield) {
case A_VPI:
if (!is_atm)
bpf_error("'vpi' supported only on raw ATM");
if (off_vpi == (u_int)-1)
abort();
b0 = gen_ncmp(OR_LINK, off_vpi, BPF_B, 0xffffffff, jtype,
reverse, jvalue);
break;
case A_VCI:
if (!is_atm)
bpf_error("'vci' supported only on raw ATM");
if (off_vci == (u_int)-1)
abort();
b0 = gen_ncmp(OR_LINK, off_vci, BPF_H, 0xffffffff, jtype,
reverse, jvalue);
break;
case A_PROTOTYPE:
if (off_proto == (u_int)-1)
abort(); /* XXX - this isn't on FreeBSD */
b0 = gen_ncmp(OR_LINK, off_proto, BPF_B, 0x0f, jtype,
reverse, jvalue);
break;
case A_MSGTYPE:
if (off_payload == (u_int)-1)
abort();
b0 = gen_ncmp(OR_LINK, off_payload + MSG_TYPE_POS, BPF_B,
0xffffffff, jtype, reverse, jvalue);
break;
case A_CALLREFTYPE:
if (!is_atm)
bpf_error("'callref' supported only on raw ATM");
if (off_proto == (u_int)-1)
abort();
b0 = gen_ncmp(OR_LINK, off_proto, BPF_B, 0xffffffff,
jtype, reverse, jvalue);
break;
default:
abort();
}
return b0;
}
struct block *
gen_atmtype_abbrev(type)
int type;
{
struct block *b0, *b1;
switch (type) {
case A_METAC:
/* Get all packets in Meta signalling Circuit */
if (!is_atm)
bpf_error("'metac' supported only on raw ATM");
b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(A_VCI, 1, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_BCC:
/* Get all packets in Broadcast Circuit*/
if (!is_atm)
bpf_error("'bcc' supported only on raw ATM");
b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(A_VCI, 2, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_OAMF4SC:
/* Get all cells in Segment OAM F4 circuit*/
if (!is_atm)
bpf_error("'oam4sc' supported only on raw ATM");
b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(A_VCI, 3, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_OAMF4EC:
/* Get all cells in End-to-End OAM F4 Circuit*/
if (!is_atm)
bpf_error("'oam4ec' supported only on raw ATM");
b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(A_VCI, 4, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_SC:
/* Get all packets in connection Signalling Circuit */
if (!is_atm)
bpf_error("'sc' supported only on raw ATM");
b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(A_VCI, 5, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_ILMIC:
/* Get all packets in ILMI Circuit */
if (!is_atm)
bpf_error("'ilmic' supported only on raw ATM");
b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
b1 = gen_atmfield_code(A_VCI, 16, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_LANE:
/* Get all LANE packets */
if (!is_atm)
bpf_error("'lane' supported only on raw ATM");
b1 = gen_atmfield_code(A_PROTOTYPE, PT_LANE, BPF_JEQ, 0);
/*
* Arrange that all subsequent tests assume LANE
* rather than LLC-encapsulated packets, and set
* the offsets appropriately for LANE-encapsulated
* Ethernet.
*
* "off_mac" is the offset of the Ethernet header,
* which is 2 bytes past the ATM pseudo-header
* (skipping the pseudo-header and 2-byte LE Client
* field). The other offsets are Ethernet offsets
* relative to "off_mac".
*/
is_lane = 1;
off_mac = off_payload + 2; /* MAC header */
off_linktype = off_mac + 12;
off_macpl = off_mac + 14; /* Ethernet */
off_nl = 0; /* Ethernet II */
off_nl_nosnap = 3; /* 802.3+802.2 */
break;
case A_LLC:
/* Get all LLC-encapsulated packets */
if (!is_atm)
bpf_error("'llc' supported only on raw ATM");
b1 = gen_atmfield_code(A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
is_lane = 0;
break;
default:
abort();
}
return b1;
}
/*
* Filtering for MTP2 messages based on li value
* FISU, length is null
* LSSU, length is 1 or 2
* MSU, length is 3 or more
*/
struct block *
gen_mtp2type_abbrev(type)
int type;
{
struct block *b0, *b1;
switch (type) {
case M_FISU:
if ( (linktype != DLT_MTP2) &&
(linktype != DLT_ERF) &&
(linktype != DLT_MTP2_WITH_PHDR) )
bpf_error("'fisu' supported only on MTP2");
/* gen_ncmp(offrel, offset, size, mask, jtype, reverse, value) */
b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JEQ, 0, 0);
break;
case M_LSSU:
if ( (linktype != DLT_MTP2) &&
(linktype != DLT_ERF) &&
(linktype != DLT_MTP2_WITH_PHDR) )
bpf_error("'lssu' supported only on MTP2");
b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 1, 2);
b1 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 0, 0);
gen_and(b1, b0);
break;
case M_MSU:
if ( (linktype != DLT_MTP2) &&
(linktype != DLT_ERF) &&
(linktype != DLT_MTP2_WITH_PHDR) )
bpf_error("'msu' supported only on MTP2");
b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 0, 2);
break;
default:
abort();
}
return b0;
}
struct block *
gen_mtp3field_code(mtp3field, jvalue, jtype, reverse)
int mtp3field;
bpf_u_int32 jvalue;
bpf_u_int32 jtype;
int reverse;
{
struct block *b0;
bpf_u_int32 val1 , val2 , val3;
switch (mtp3field) {
case M_SIO:
if (off_sio == (u_int)-1)
bpf_error("'sio' supported only on SS7");
/* sio coded on 1 byte so max value 255 */
if(jvalue > 255)
bpf_error("sio value %u too big; max value = 255",
jvalue);
b0 = gen_ncmp(OR_PACKET, off_sio, BPF_B, 0xffffffff,
(u_int)jtype, reverse, (u_int)jvalue);
break;
case M_OPC:
if (off_opc == (u_int)-1)
bpf_error("'opc' supported only on SS7");
/* opc coded on 14 bits so max value 16383 */
if (jvalue > 16383)
bpf_error("opc value %u too big; max value = 16383",
jvalue);
/* the following instructions are made to convert jvalue
* to the form used to write opc in an ss7 message*/
val1 = jvalue & 0x00003c00;
val1 = val1 >>10;
val2 = jvalue & 0x000003fc;
val2 = val2 <<6;
val3 = jvalue & 0x00000003;
val3 = val3 <<22;
jvalue = val1 + val2 + val3;
b0 = gen_ncmp(OR_PACKET, off_opc, BPF_W, 0x00c0ff0f,
(u_int)jtype, reverse, (u_int)jvalue);
break;
case M_DPC:
if (off_dpc == (u_int)-1)
bpf_error("'dpc' supported only on SS7");
/* dpc coded on 14 bits so max value 16383 */
if (jvalue > 16383)
bpf_error("dpc value %u too big; max value = 16383",
jvalue);
/* the following instructions are made to convert jvalue
* to the forme used to write dpc in an ss7 message*/
val1 = jvalue & 0x000000ff;
val1 = val1 << 24;
val2 = jvalue & 0x00003f00;
val2 = val2 << 8;
jvalue = val1 + val2;
b0 = gen_ncmp(OR_PACKET, off_dpc, BPF_W, 0xff3f0000,
(u_int)jtype, reverse, (u_int)jvalue);
break;
case M_SLS:
if (off_sls == (u_int)-1)
bpf_error("'sls' supported only on SS7");
/* sls coded on 4 bits so max value 15 */
if (jvalue > 15)
bpf_error("sls value %u too big; max value = 15",
jvalue);
/* the following instruction is made to convert jvalue
* to the forme used to write sls in an ss7 message*/
jvalue = jvalue << 4;
b0 = gen_ncmp(OR_PACKET, off_sls, BPF_B, 0xf0,
(u_int)jtype,reverse, (u_int)jvalue);
break;
default:
abort();
}
return b0;
}
static struct block *
gen_msg_abbrev(type)
int type;
{
struct block *b1;
/*
* Q.2931 signalling protocol messages for handling virtual circuits
* establishment and teardown
*/
switch (type) {
case A_SETUP:
b1 = gen_atmfield_code(A_MSGTYPE, SETUP, BPF_JEQ, 0);
break;
case A_CALLPROCEED:
b1 = gen_atmfield_code(A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0);
break;
case A_CONNECT:
b1 = gen_atmfield_code(A_MSGTYPE, CONNECT, BPF_JEQ, 0);
break;
case A_CONNECTACK:
b1 = gen_atmfield_code(A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0);
break;
case A_RELEASE:
b1 = gen_atmfield_code(A_MSGTYPE, RELEASE, BPF_JEQ, 0);
break;
case A_RELEASE_DONE:
b1 = gen_atmfield_code(A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0);
break;
default:
abort();
}
return b1;
}
struct block *
gen_atmmulti_abbrev(type)
int type;
{
struct block *b0, *b1;
switch (type) {
case A_OAM:
if (!is_atm)
bpf_error("'oam' supported only on raw ATM");
b1 = gen_atmmulti_abbrev(A_OAMF4);
break;
case A_OAMF4:
if (!is_atm)
bpf_error("'oamf4' supported only on raw ATM");
/* OAM F4 type */
b0 = gen_atmfield_code(A_VCI, 3, BPF_JEQ, 0);
b1 = gen_atmfield_code(A_VCI, 4, BPF_JEQ, 0);
gen_or(b0, b1);
b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0);
gen_and(b0, b1);
break;
case A_CONNECTMSG:
/*
* Get Q.2931 signalling messages for switched
* virtual connection
*/
if (!is_atm)
bpf_error("'connectmsg' supported only on raw ATM");
b0 = gen_msg_abbrev(A_SETUP);
b1 = gen_msg_abbrev(A_CALLPROCEED);
gen_or(b0, b1);
b0 = gen_msg_abbrev(A_CONNECT);
gen_or(b0, b1);
b0 = gen_msg_abbrev(A_CONNECTACK);
gen_or(b0, b1);
b0 = gen_msg_abbrev(A_RELEASE);
gen_or(b0, b1);
b0 = gen_msg_abbrev(A_RELEASE_DONE);
gen_or(b0, b1);
b0 = gen_atmtype_abbrev(A_SC);
gen_and(b0, b1);
break;
case A_METACONNECT:
if (!is_atm)
bpf_error("'metaconnect' supported only on raw ATM");
b0 = gen_msg_abbrev(A_SETUP);
b1 = gen_msg_abbrev(A_CALLPROCEED);
gen_or(b0, b1);
b0 = gen_msg_abbrev(A_CONNECT);
gen_or(b0, b1);
b0 = gen_msg_abbrev(A_RELEASE);
gen_or(b0, b1);
b0 = gen_msg_abbrev(A_RELEASE_DONE);
gen_or(b0, b1);
b0 = gen_atmtype_abbrev(A_METAC);
gen_and(b0, b1);
break;
default:
abort();
}
return b1;
}
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