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5923c29332
freebsd/sys/netinet/ip_input.c
Gleb Smirnoff 5923c29332 Merge from projects/counters: TCP/IP stats. 
Convert 'struct ipstat' and 'struct tcpstat' to counter(9).

  This speeds up IP forwarding at extreme packet rates, and
makes accounting more precise.

Sponsored by:	Nginx, Inc.
2013-04-08 19:57:21 +00:00

1820 lines
46 KiB
C
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/*-
* Copyright (c) 1982, 1986, 1988, 1993
* 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 the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ip_input.c 8.2 (Berkeley) 1/4/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_bootp.h"
#include "opt_ipfw.h"
#include "opt_ipstealth.h"
#include "opt_ipsec.h"
#include "opt_route.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/rwlock.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>
#include <net/pfil.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/if_var.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/netisr.h>
#include <net/vnet.h>
#include <net/flowtable.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet/ip_fw.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_options.h>
#include <machine/in_cksum.h>
#include <netinet/ip_carp.h>
#ifdef IPSEC
#include <netinet/ip_ipsec.h>
#endif /* IPSEC */
#include <sys/socketvar.h>
#include <security/mac/mac_framework.h>
#ifdef CTASSERT
CTASSERT(sizeof(struct ip) == 20);
#endif
struct rwlock in_ifaddr_lock;
RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock");
VNET_DEFINE(int, rsvp_on);
VNET_DEFINE(int, ipforwarding);
SYSCTL_VNET_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
&VNET_NAME(ipforwarding), 0,
"Enable IP forwarding between interfaces");
static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */
#define V_ipsendredirects VNET(ipsendredirects)
SYSCTL_VNET_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
&VNET_NAME(ipsendredirects), 0,
"Enable sending IP redirects");
static VNET_DEFINE(int, ip_keepfaith);
#define V_ip_keepfaith VNET(ip_keepfaith)
SYSCTL_VNET_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
&VNET_NAME(ip_keepfaith), 0,
"Enable packet capture for FAITH IPv4->IPv6 translater daemon");
static VNET_DEFINE(int, ip_sendsourcequench);
#define V_ip_sendsourcequench VNET(ip_sendsourcequench)
SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
&VNET_NAME(ip_sendsourcequench), 0,
"Enable the transmission of source quench packets");
VNET_DEFINE(int, ip_do_randomid);
SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW,
&VNET_NAME(ip_do_randomid), 0,
"Assign random ip_id values");
/*
* XXX - Setting ip_checkinterface mostly implements the receive side of
* the Strong ES model described in RFC 1122, but since the routing table
* and transmit implementation do not implement the Strong ES model,
* setting this to 1 results in an odd hybrid.
*
* XXX - ip_checkinterface currently must be disabled if you use ipnat
* to translate the destination address to another local interface.
*
* XXX - ip_checkinterface must be disabled if you add IP aliases
* to the loopback interface instead of the interface where the
* packets for those addresses are received.
*/
static VNET_DEFINE(int, ip_checkinterface);
#define V_ip_checkinterface VNET(ip_checkinterface)
SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
&VNET_NAME(ip_checkinterface), 0,
"Verify packet arrives on correct interface");
VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */
static struct netisr_handler ip_nh = {
.nh_name = "ip",
.nh_handler = ip_input,
.nh_proto = NETISR_IP,
.nh_policy = NETISR_POLICY_FLOW,
};
extern struct domain inetdomain;
extern struct protosw inetsw[];
u_char ip_protox[IPPROTO_MAX];
VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */
VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */
VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */
static VNET_DEFINE(uma_zone_t, ipq_zone);
static VNET_DEFINE(TAILQ_HEAD(ipqhead, ipq), ipq[IPREASS_NHASH]);
static struct mtx ipqlock;
#define V_ipq_zone VNET(ipq_zone)
#define V_ipq VNET(ipq)
#define IPQ_LOCK() mtx_lock(&ipqlock)
#define IPQ_UNLOCK() mtx_unlock(&ipqlock)
#define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF)
#define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED)
static void maxnipq_update(void);
static void ipq_zone_change(void *);
static void ip_drain_locked(void);
static VNET_DEFINE(int, maxnipq); /* Administrative limit on # reass queues. */
static VNET_DEFINE(int, nipq); /* Total # of reass queues */
#define V_maxnipq VNET(maxnipq)
#define V_nipq VNET(nipq)
SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD,
&VNET_NAME(nipq), 0,
"Current number of IPv4 fragment reassembly queue entries");
static VNET_DEFINE(int, maxfragsperpacket);
#define V_maxfragsperpacket VNET(maxfragsperpacket)
SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
&VNET_NAME(maxfragsperpacket), 0,
"Maximum number of IPv4 fragments allowed per packet");
#ifdef IPCTL_DEFMTU
SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
&ip_mtu, 0, "Default MTU");
#endif
#ifdef IPSTEALTH
VNET_DEFINE(int, ipstealth);
SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
&VNET_NAME(ipstealth), 0,
"IP stealth mode, no TTL decrementation on forwarding");
#endif
#ifdef FLOWTABLE
static VNET_DEFINE(int, ip_output_flowtable_size) = 2048;
VNET_DEFINE(struct flowtable *, ip_ft);
#define V_ip_output_flowtable_size VNET(ip_output_flowtable_size)
SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, output_flowtable_size, CTLFLAG_RDTUN,
&VNET_NAME(ip_output_flowtable_size), 2048,
"number of entries in the per-cpu output flow caches");
#endif
static void ip_freef(struct ipqhead *, struct ipq *);
/*
* IP statistics are stored in struct ipstat_p, which is
* an "array" of counter(9)s. Although it isn't a real
* array, we treat it as array to reduce code bloat.
*/
VNET_DEFINE(struct ipstat_p, ipstatp);
static void
vnet_ipstatp_init(const void *unused)
{
counter_u64_t *c;
int i;
for (i = 0, c = (counter_u64_t *)&V_ipstatp;
i < sizeof(V_ipstatp) / sizeof(counter_u64_t);
i++, c++) {
*c = counter_u64_alloc(M_WAITOK);
counter_u64_zero(*c);
}
}
VNET_SYSINIT(vnet_ipstatp_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
vnet_ipstatp_init, NULL);
#ifdef VIMAGE
static void
vnet_ipstatp_uninit(const void *unused)
{
counter_u64_t *c;
int i;
for (i = 0, c = (counter_u64_t *)&V_ipstatp;
i < sizeof(V_ipstatp) / sizeof(counter_u64_t);
i++, c++)
counter_u64_free(*c);
}
VNET_SYSUNINIT(vnet_ipstatp_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
vnet_ipstatp_uninit, NULL);
#endif /* VIMAGE */
static int
ipstat_sysctl(SYSCTL_HANDLER_ARGS)
{
struct ipstat ipstat;
counter_u64_t *c;
uint64_t *v;
int i;
for (i = 0, c = (counter_u64_t *)&V_ipstatp, v = (uint64_t *)&ipstat;
i < sizeof(V_ipstatp) / sizeof(counter_u64_t);
i++, c++, v++) {
*v = counter_u64_fetch(*c);
/*
* Old interface allowed to rewrite 'struct ipstat', and
* netstat(1) used it to zero the structure. To keep
* compatibility with old netstat(1) we will zero out
* statistics on every write attempt, however we no longer
* support writing arbitrary fake values to the statistics.
*/
if (req->newptr)
counter_u64_zero(*c);
}
return (SYSCTL_OUT(req, &ipstat, sizeof(ipstat)));
}
SYSCTL_VNET_PROC(_net_inet_ip, IPCTL_STATS, stats, CTLTYPE_OPAQUE | CTLFLAG_RW,
NULL, 0, ipstat_sysctl, "I",
"IP statistics (struct ipstat, netinet/ip_var.h)");
/*
* Kernel module interface for updating ipstat. The argument is an index
* into ipstat treated as an array.
*/
void
kmod_ipstat_inc(int statnum)
{
counter_u64_add((counter_u64_t )&V_ipstatp + statnum, 1);
}
void
kmod_ipstat_dec(int statnum)
{
counter_u64_add((counter_u64_t )&V_ipstatp + statnum, -1);
}
static int
sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
{
int error, qlimit;
netisr_getqlimit(&ip_nh, &qlimit);
error = sysctl_handle_int(oidp, &qlimit, 0, req);
if (error || !req->newptr)
return (error);
if (qlimit < 1)
return (EINVAL);
return (netisr_setqlimit(&ip_nh, qlimit));
}
SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen,
CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I",
"Maximum size of the IP input queue");
static int
sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS)
{
u_int64_t qdrops_long;
int error, qdrops;
netisr_getqdrops(&ip_nh, &qdrops_long);
qdrops = qdrops_long;
error = sysctl_handle_int(oidp, &qdrops, 0, req);
if (error || !req->newptr)
return (error);
if (qdrops != 0)
return (EINVAL);
netisr_clearqdrops(&ip_nh);
return (0);
}
SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops,
CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I",
"Number of packets dropped from the IP input queue");
/*
* IP initialization: fill in IP protocol switch table.
* All protocols not implemented in kernel go to raw IP protocol handler.
*/
void
ip_init(void)
{
struct protosw *pr;
int i;
V_ip_id = time_second & 0xffff;
TAILQ_INIT(&V_in_ifaddrhead);
V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask);
/* Initialize IP reassembly queue. */
for (i = 0; i < IPREASS_NHASH; i++)
TAILQ_INIT(&V_ipq[i]);
V_maxnipq = nmbclusters / 32;
V_maxfragsperpacket = 16;
V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL,
NULL, UMA_ALIGN_PTR, 0);
maxnipq_update();
/* Initialize packet filter hooks. */
V_inet_pfil_hook.ph_type = PFIL_TYPE_AF;
V_inet_pfil_hook.ph_af = AF_INET;
if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0)
printf("%s: WARNING: unable to register pfil hook, "
"error %d\n", __func__, i);
#ifdef FLOWTABLE
if (TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size",
&V_ip_output_flowtable_size)) {
if (V_ip_output_flowtable_size < 256)
V_ip_output_flowtable_size = 256;
if (!powerof2(V_ip_output_flowtable_size)) {
printf("flowtable must be power of 2 size\n");
V_ip_output_flowtable_size = 2048;
}
} else {
/*
* round up to the next power of 2
*/
V_ip_output_flowtable_size = 1 << fls((1024 + maxusers * 64)-1);
}
V_ip_ft = flowtable_alloc("ipv4", V_ip_output_flowtable_size, FL_PCPU);
#endif
/* Skip initialization of globals for non-default instances. */
if (!IS_DEFAULT_VNET(curvnet))
return;
pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == NULL)
panic("ip_init: PF_INET not found");
/* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
for (i = 0; i < IPPROTO_MAX; i++)
ip_protox[i] = pr - inetsw;
/*
* Cycle through IP protocols and put them into the appropriate place
* in ip_protox[].
*/
for (pr = inetdomain.dom_protosw;
pr < inetdomain.dom_protoswNPROTOSW; pr++)
if (pr->pr_domain->dom_family == PF_INET &&
pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
/* Be careful to only index valid IP protocols. */
if (pr->pr_protocol < IPPROTO_MAX)
ip_protox[pr->pr_protocol] = pr - inetsw;
}
EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change,
NULL, EVENTHANDLER_PRI_ANY);
/* Initialize various other remaining things. */
IPQ_LOCK_INIT();
netisr_register(&ip_nh);
}
#ifdef VIMAGE
void
ip_destroy(void)
{
/* Cleanup in_ifaddr hash table; should be empty. */
hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask);
IPQ_LOCK();
ip_drain_locked();
IPQ_UNLOCK();
uma_zdestroy(V_ipq_zone);
}
#endif
/*
* Ip input routine. Checksum and byte swap header. If fragmented
* try to reassemble. Process options. Pass to next level.
*/
void
ip_input(struct mbuf *m)
{
struct ip *ip = NULL;
struct in_ifaddr *ia = NULL;
struct ifaddr *ifa;
struct ifnet *ifp;
int checkif, hlen = 0;
uint16_t sum, ip_len;
int dchg = 0; /* dest changed after fw */
struct in_addr odst; /* original dst address */
M_ASSERTPKTHDR(m);
if (m->m_flags & M_FASTFWD_OURS) {
m->m_flags &= ~M_FASTFWD_OURS;
/* Set up some basics that will be used later. */
ip = mtod(m, struct ip *);
hlen = ip->ip_hl << 2;
ip_len = ntohs(ip->ip_len);
goto ours;
}
IPSTAT_INC(ips_total);
if (m->m_pkthdr.len < sizeof(struct ip))
goto tooshort;
if (m->m_len < sizeof (struct ip) &&
(m = m_pullup(m, sizeof (struct ip))) == NULL) {
IPSTAT_INC(ips_toosmall);
return;
}
ip = mtod(m, struct ip *);
if (ip->ip_v != IPVERSION) {
IPSTAT_INC(ips_badvers);
goto bad;
}
hlen = ip->ip_hl << 2;
if (hlen < sizeof(struct ip)) { /* minimum header length */
IPSTAT_INC(ips_badhlen);
goto bad;
}
if (hlen > m->m_len) {
if ((m = m_pullup(m, hlen)) == NULL) {
IPSTAT_INC(ips_badhlen);
return;
}
ip = mtod(m, struct ip *);
}
/* 127/8 must not appear on wire - RFC1122 */
ifp = m->m_pkthdr.rcvif;
if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
(ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
IPSTAT_INC(ips_badaddr);
goto bad;
}
}
if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
} else {
if (hlen == sizeof(struct ip)) {
sum = in_cksum_hdr(ip);
} else {
sum = in_cksum(m, hlen);
}
}
if (sum) {
IPSTAT_INC(ips_badsum);
goto bad;
}
#ifdef ALTQ
if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0)
/* packet is dropped by traffic conditioner */
return;
#endif
ip_len = ntohs(ip->ip_len);
if (ip_len < hlen) {
IPSTAT_INC(ips_badlen);
goto bad;
}
/*
* Check that the amount of data in the buffers
* is as at least much as the IP header would have us expect.
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
if (m->m_pkthdr.len < ip_len) {
tooshort:
IPSTAT_INC(ips_tooshort);
goto bad;
}
if (m->m_pkthdr.len > ip_len) {
if (m->m_len == m->m_pkthdr.len) {
m->m_len = ip_len;
m->m_pkthdr.len = ip_len;
} else
m_adj(m, ip_len - m->m_pkthdr.len);
}
#ifdef IPSEC
/*
* Bypass packet filtering for packets previously handled by IPsec.
*/
if (ip_ipsec_filtertunnel(m))
goto passin;
#endif /* IPSEC */
/*
* Run through list of hooks for input packets.
*
* NB: Beware of the destination address changing (e.g.
* by NAT rewriting). When this happens, tell
* ip_forward to do the right thing.
*/
/* Jump over all PFIL processing if hooks are not active. */
if (!PFIL_HOOKED(&V_inet_pfil_hook))
goto passin;
odst = ip->ip_dst;
if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0)
return;
if (m == NULL) /* consumed by filter */
return;
ip = mtod(m, struct ip *);
dchg = (odst.s_addr != ip->ip_dst.s_addr);
ifp = m->m_pkthdr.rcvif;
if (m->m_flags & M_FASTFWD_OURS) {
m->m_flags &= ~M_FASTFWD_OURS;
goto ours;
}
if (m->m_flags & M_IP_NEXTHOP) {
dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL);
if (dchg != 0) {
/*
* Directly ship the packet on. This allows
* forwarding packets originally destined to us
* to some other directly connected host.
*/
ip_forward(m, 1);
return;
}
}
passin:
/*
* Process options and, if not destined for us,
* ship it on. ip_dooptions returns 1 when an
* error was detected (causing an icmp message
* to be sent and the original packet to be freed).
*/
if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
return;
/* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
* matter if it is destined to another node, or whether it is
* a multicast one, RSVP wants it! and prevents it from being forwarded
* anywhere else. Also checks if the rsvp daemon is running before
* grabbing the packet.
*/
if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP)
goto ours;
/*
* Check our list of addresses, to see if the packet is for us.
* If we don't have any addresses, assume any unicast packet
* we receive might be for us (and let the upper layers deal
* with it).
*/
if (TAILQ_EMPTY(&V_in_ifaddrhead) &&
(m->m_flags & (M_MCAST|M_BCAST)) == 0)
goto ours;
/*
* Enable a consistency check between the destination address
* and the arrival interface for a unicast packet (the RFC 1122
* strong ES model) if IP forwarding is disabled and the packet
* is not locally generated and the packet is not subject to
* 'ipfw fwd'.
*
* XXX - Checking also should be disabled if the destination
* address is ipnat'ed to a different interface.
*
* XXX - Checking is incompatible with IP aliases added
* to the loopback interface instead of the interface where
* the packets are received.
*
* XXX - This is the case for carp vhost IPs as well so we
* insert a workaround. If the packet got here, we already
* checked with carp_iamatch() and carp_forus().
*/
checkif = V_ip_checkinterface && (V_ipforwarding == 0) &&
ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) &&
ifp->if_carp == NULL && (dchg == 0);
/*
* Check for exact addresses in the hash bucket.
*/
/* IN_IFADDR_RLOCK(); */
LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
/*
* If the address matches, verify that the packet
* arrived via the correct interface if checking is
* enabled.
*/
if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr &&
(!checkif || ia->ia_ifp == ifp)) {
ifa_ref(&ia->ia_ifa);
/* IN_IFADDR_RUNLOCK(); */
goto ours;
}
}
/* IN_IFADDR_RUNLOCK(); */
/*
* Check for broadcast addresses.
*
* Only accept broadcast packets that arrive via the matching
* interface. Reception of forwarded directed broadcasts would
* be handled via ip_forward() and ether_output() with the loopback
* into the stack for SIMPLEX interfaces handled by ether_output().
*/
if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
IF_ADDR_RLOCK(ifp);
TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
ia = ifatoia(ifa);
if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
ip->ip_dst.s_addr) {
ifa_ref(ifa);
IF_ADDR_RUNLOCK(ifp);
goto ours;
}
#ifdef BOOTP_COMPAT
if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
ifa_ref(ifa);
IF_ADDR_RUNLOCK(ifp);
goto ours;
}
#endif
}
IF_ADDR_RUNLOCK(ifp);
ia = NULL;
}
/* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */
if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) {
IPSTAT_INC(ips_cantforward);
m_freem(m);
return;
}
if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
if (V_ip_mrouter) {
/*
* If we are acting as a multicast router, all
* incoming multicast packets are passed to the
* kernel-level multicast forwarding function.
* The packet is returned (relatively) intact; if
* ip_mforward() returns a non-zero value, the packet
* must be discarded, else it may be accepted below.
*/
if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) {
IPSTAT_INC(ips_cantforward);
m_freem(m);
return;
}
/*
* The process-level routing daemon needs to receive
* all multicast IGMP packets, whether or not this
* host belongs to their destination groups.
*/
if (ip->ip_p == IPPROTO_IGMP)
goto ours;
IPSTAT_INC(ips_forward);
}
/*
* Assume the packet is for us, to avoid prematurely taking
* a lock on the in_multi hash. Protocols must perform
* their own filtering and update statistics accordingly.
*/
goto ours;
}
if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
goto ours;
if (ip->ip_dst.s_addr == INADDR_ANY)
goto ours;
/*
* FAITH(Firewall Aided Internet Translator)
*/
if (ifp && ifp->if_type == IFT_FAITH) {
if (V_ip_keepfaith) {
if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
goto ours;
}
m_freem(m);
return;
}
/*
* Not for us; forward if possible and desirable.
*/
if (V_ipforwarding == 0) {
IPSTAT_INC(ips_cantforward);
m_freem(m);
} else {
#ifdef IPSEC
if (ip_ipsec_fwd(m))
goto bad;
#endif /* IPSEC */
ip_forward(m, dchg);
}
return;
ours:
#ifdef IPSTEALTH
/*
* IPSTEALTH: Process non-routing options only
* if the packet is destined for us.
*/
if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1)) {
if (ia != NULL)
ifa_free(&ia->ia_ifa);
return;
}
#endif /* IPSTEALTH */
/* Count the packet in the ip address stats */
if (ia != NULL) {
ia->ia_ifa.if_ipackets++;
ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
ifa_free(&ia->ia_ifa);
}
/*
* Attempt reassembly; if it succeeds, proceed.
* ip_reass() will return a different mbuf.
*/
if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
m = ip_reass(m);
if (m == NULL)
return;
ip = mtod(m, struct ip *);
/* Get the header length of the reassembled packet */
hlen = ip->ip_hl << 2;
}
#ifdef IPSEC
/*
* enforce IPsec policy checking if we are seeing last header.
* note that we do not visit this with protocols with pcb layer
* code - like udp/tcp/raw ip.
*/
if (ip_ipsec_input(m))
goto bad;
#endif /* IPSEC */
/*
* Switch out to protocol's input routine.
*/
IPSTAT_INC(ips_delivered);
(*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
return;
bad:
m_freem(m);
}
/*
* After maxnipq has been updated, propagate the change to UMA. The UMA zone
* max has slightly different semantics than the sysctl, for historical
* reasons.
*/
static void
maxnipq_update(void)
{
/*
* -1 for unlimited allocation.
*/
if (V_maxnipq < 0)
uma_zone_set_max(V_ipq_zone, 0);
/*
* Positive number for specific bound.
*/
if (V_maxnipq > 0)
uma_zone_set_max(V_ipq_zone, V_maxnipq);
/*
* Zero specifies no further fragment queue allocation -- set the
* bound very low, but rely on implementation elsewhere to actually
* prevent allocation and reclaim current queues.
*/
if (V_maxnipq == 0)
uma_zone_set_max(V_ipq_zone, 1);
}
static void
ipq_zone_change(void *tag)
{
if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) {
V_maxnipq = nmbclusters / 32;
maxnipq_update();
}
}
static int
sysctl_maxnipq(SYSCTL_HANDLER_ARGS)
{
int error, i;
i = V_maxnipq;
error = sysctl_handle_int(oidp, &i, 0, req);
if (error || !req->newptr)
return (error);
/*
* XXXRW: Might be a good idea to sanity check the argument and place
* an extreme upper bound.
*/
if (i < -1)
return (EINVAL);
V_maxnipq = i;
maxnipq_update();
return (0);
}
SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW,
NULL, 0, sysctl_maxnipq, "I",
"Maximum number of IPv4 fragment reassembly queue entries");
/*
* Take incoming datagram fragment and try to reassemble it into
* whole datagram. If the argument is the first fragment or one
* in between the function will return NULL and store the mbuf
* in the fragment chain. If the argument is the last fragment
* the packet will be reassembled and the pointer to the new
* mbuf returned for further processing. Only m_tags attached
* to the first packet/fragment are preserved.
* The IP header is *NOT* adjusted out of iplen.
*/
struct mbuf *
ip_reass(struct mbuf *m)
{
struct ip *ip;
struct mbuf *p, *q, *nq, *t;
struct ipq *fp = NULL;
struct ipqhead *head;
int i, hlen, next;
u_int8_t ecn, ecn0;
u_short hash;
/* If maxnipq or maxfragsperpacket are 0, never accept fragments. */
if (V_maxnipq == 0 || V_maxfragsperpacket == 0) {
IPSTAT_INC(ips_fragments);
IPSTAT_INC(ips_fragdropped);
m_freem(m);
return (NULL);
}
ip = mtod(m, struct ip *);
hlen = ip->ip_hl << 2;
hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
head = &V_ipq[hash];
IPQ_LOCK();
/*
* Look for queue of fragments
* of this datagram.
*/
TAILQ_FOREACH(fp, head, ipq_list)
if (ip->ip_id == fp->ipq_id &&
ip->ip_src.s_addr == fp->ipq_src.s_addr &&
ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
#ifdef MAC
mac_ipq_match(m, fp) &&
#endif
ip->ip_p == fp->ipq_p)
goto found;
fp = NULL;
/*
* Attempt to trim the number of allocated fragment queues if it
* exceeds the administrative limit.
*/
if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) {
/*
* drop something from the tail of the current queue
* before proceeding further
*/
struct ipq *q = TAILQ_LAST(head, ipqhead);
if (q == NULL) { /* gak */
for (i = 0; i < IPREASS_NHASH; i++) {
struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead);
if (r) {
IPSTAT_ADD(ips_fragtimeout,
r->ipq_nfrags);
ip_freef(&V_ipq[i], r);
break;
}
}
} else {
IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags);
ip_freef(head, q);
}
}
found:
/*
* Adjust ip_len to not reflect header,
* convert offset of this to bytes.
*/
ip->ip_len = htons(ntohs(ip->ip_len) - hlen);
if (ip->ip_off & htons(IP_MF)) {
/*
* Make sure that fragments have a data length
* that's a non-zero multiple of 8 bytes.
*/
if (ip->ip_len == htons(0) || (ntohs(ip->ip_len) & 0x7) != 0) {
IPSTAT_INC(ips_toosmall); /* XXX */
goto dropfrag;
}
m->m_flags |= M_FRAG;
} else
m->m_flags &= ~M_FRAG;
ip->ip_off = htons(ntohs(ip->ip_off) << 3);
/*
* Attempt reassembly; if it succeeds, proceed.
* ip_reass() will return a different mbuf.
*/
IPSTAT_INC(ips_fragments);
m->m_pkthdr.header = ip;
/* Previous ip_reass() started here. */
/*
* Presence of header sizes in mbufs
* would confuse code below.
*/
m->m_data += hlen;
m->m_len -= hlen;
/*
* If first fragment to arrive, create a reassembly queue.
*/
if (fp == NULL) {
fp = uma_zalloc(V_ipq_zone, M_NOWAIT);
if (fp == NULL)
goto dropfrag;
#ifdef MAC
if (mac_ipq_init(fp, M_NOWAIT) != 0) {
uma_zfree(V_ipq_zone, fp);
fp = NULL;
goto dropfrag;
}
mac_ipq_create(m, fp);
#endif
TAILQ_INSERT_HEAD(head, fp, ipq_list);
V_nipq++;
fp->ipq_nfrags = 1;
fp->ipq_ttl = IPFRAGTTL;
fp->ipq_p = ip->ip_p;
fp->ipq_id = ip->ip_id;
fp->ipq_src = ip->ip_src;
fp->ipq_dst = ip->ip_dst;
fp->ipq_frags = m;
m->m_nextpkt = NULL;
goto done;
} else {
fp->ipq_nfrags++;
#ifdef MAC
mac_ipq_update(m, fp);
#endif
}
#define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
/*
* Handle ECN by comparing this segment with the first one;
* if CE is set, do not lose CE.
* drop if CE and not-ECT are mixed for the same packet.
*/
ecn = ip->ip_tos & IPTOS_ECN_MASK;
ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
if (ecn == IPTOS_ECN_CE) {
if (ecn0 == IPTOS_ECN_NOTECT)
goto dropfrag;
if (ecn0 != IPTOS_ECN_CE)
GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
}
if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT)
goto dropfrag;
/*
* Find a segment which begins after this one does.
*/
for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
if (ntohs(GETIP(q)->ip_off) > ntohs(ip->ip_off))
break;
/*
* If there is a preceding segment, it may provide some of
* our data already. If so, drop the data from the incoming
* segment. If it provides all of our data, drop us, otherwise
* stick new segment in the proper place.
*
* If some of the data is dropped from the preceding
* segment, then it's checksum is invalidated.
*/
if (p) {
i = ntohs(GETIP(p)->ip_off) + ntohs(GETIP(p)->ip_len) -
ntohs(ip->ip_off);
if (i > 0) {
if (i >= ntohs(ip->ip_len))
goto dropfrag;
m_adj(m, i);
m->m_pkthdr.csum_flags = 0;
ip->ip_off = htons(ntohs(ip->ip_off) + i);
ip->ip_len = htons(ntohs(ip->ip_len) - i);
}
m->m_nextpkt = p->m_nextpkt;
p->m_nextpkt = m;
} else {
m->m_nextpkt = fp->ipq_frags;
fp->ipq_frags = m;
}
/*
* While we overlap succeeding segments trim them or,
* if they are completely covered, dequeue them.
*/
for (; q != NULL && ntohs(ip->ip_off) + ntohs(ip->ip_len) >
ntohs(GETIP(q)->ip_off); q = nq) {
i = (ntohs(ip->ip_off) + ntohs(ip->ip_len)) -
ntohs(GETIP(q)->ip_off);
if (i < ntohs(GETIP(q)->ip_len)) {
GETIP(q)->ip_len = htons(ntohs(GETIP(q)->ip_len) - i);
GETIP(q)->ip_off = htons(ntohs(GETIP(q)->ip_off) + i);
m_adj(q, i);
q->m_pkthdr.csum_flags = 0;
break;
}
nq = q->m_nextpkt;
m->m_nextpkt = nq;
IPSTAT_INC(ips_fragdropped);
fp->ipq_nfrags--;
m_freem(q);
}
/*
* Check for complete reassembly and perform frag per packet
* limiting.
*
* Frag limiting is performed here so that the nth frag has
* a chance to complete the packet before we drop the packet.
* As a result, n+1 frags are actually allowed per packet, but
* only n will ever be stored. (n = maxfragsperpacket.)
*
*/
next = 0;
for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
if (ntohs(GETIP(q)->ip_off) != next) {
if (fp->ipq_nfrags > V_maxfragsperpacket) {
IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
ip_freef(head, fp);
}
goto done;
}
next += ntohs(GETIP(q)->ip_len);
}
/* Make sure the last packet didn't have the IP_MF flag */
if (p->m_flags & M_FRAG) {
if (fp->ipq_nfrags > V_maxfragsperpacket) {
IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
ip_freef(head, fp);
}
goto done;
}
/*
* Reassembly is complete. Make sure the packet is a sane size.
*/
q = fp->ipq_frags;
ip = GETIP(q);
if (next + (ip->ip_hl << 2) > IP_MAXPACKET) {
IPSTAT_INC(ips_toolong);
IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
ip_freef(head, fp);
goto done;
}
/*
* Concatenate fragments.
*/
m = q;
t = m->m_next;
m->m_next = NULL;
m_cat(m, t);
nq = q->m_nextpkt;
q->m_nextpkt = NULL;
for (q = nq; q != NULL; q = nq) {
nq = q->m_nextpkt;
q->m_nextpkt = NULL;
m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
m_cat(m, q);
}
/*
* In order to do checksumming faster we do 'end-around carry' here
* (and not in for{} loop), though it implies we are not going to
* reassemble more than 64k fragments.
*/
m->m_pkthdr.csum_data =
(m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16);
#ifdef MAC
mac_ipq_reassemble(fp, m);
mac_ipq_destroy(fp);
#endif
/*
* Create header for new ip packet by modifying header of first
* packet; dequeue and discard fragment reassembly header.
* Make header visible.
*/
ip->ip_len = htons((ip->ip_hl << 2) + next);
ip->ip_src = fp->ipq_src;
ip->ip_dst = fp->ipq_dst;
TAILQ_REMOVE(head, fp, ipq_list);
V_nipq--;
uma_zfree(V_ipq_zone, fp);
m->m_len += (ip->ip_hl << 2);
m->m_data -= (ip->ip_hl << 2);
/* some debugging cruft by sklower, below, will go away soon */
if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */
m_fixhdr(m);
IPSTAT_INC(ips_reassembled);
IPQ_UNLOCK();
return (m);
dropfrag:
IPSTAT_INC(ips_fragdropped);
if (fp != NULL)
fp->ipq_nfrags--;
m_freem(m);
done:
IPQ_UNLOCK();
return (NULL);
#undef GETIP
}
/*
* Free a fragment reassembly header and all
* associated datagrams.
*/
static void
ip_freef(struct ipqhead *fhp, struct ipq *fp)
{
struct mbuf *q;
IPQ_LOCK_ASSERT();
while (fp->ipq_frags) {
q = fp->ipq_frags;
fp->ipq_frags = q->m_nextpkt;
m_freem(q);
}
TAILQ_REMOVE(fhp, fp, ipq_list);
uma_zfree(V_ipq_zone, fp);
V_nipq--;
}
/*
* IP timer processing;
* if a timer expires on a reassembly
* queue, discard it.
*/
void
ip_slowtimo(void)
{
VNET_ITERATOR_DECL(vnet_iter);
struct ipq *fp;
int i;
VNET_LIST_RLOCK_NOSLEEP();
IPQ_LOCK();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
for (i = 0; i < IPREASS_NHASH; i++) {
for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) {
struct ipq *fpp;
fpp = fp;
fp = TAILQ_NEXT(fp, ipq_list);
if(--fpp->ipq_ttl == 0) {
IPSTAT_ADD(ips_fragtimeout,
fpp->ipq_nfrags);
ip_freef(&V_ipq[i], fpp);
}
}
}
/*
* If we are over the maximum number of fragments
* (due to the limit being lowered), drain off
* enough to get down to the new limit.
*/
if (V_maxnipq >= 0 && V_nipq > V_maxnipq) {
for (i = 0; i < IPREASS_NHASH; i++) {
while (V_nipq > V_maxnipq &&
!TAILQ_EMPTY(&V_ipq[i])) {
IPSTAT_ADD(ips_fragdropped,
TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
ip_freef(&V_ipq[i],
TAILQ_FIRST(&V_ipq[i]));
}
}
}
CURVNET_RESTORE();
}
IPQ_UNLOCK();
VNET_LIST_RUNLOCK_NOSLEEP();
}
/*
* Drain off all datagram fragments.
*/
static void
ip_drain_locked(void)
{
int i;
IPQ_LOCK_ASSERT();
for (i = 0; i < IPREASS_NHASH; i++) {
while(!TAILQ_EMPTY(&V_ipq[i])) {
IPSTAT_ADD(ips_fragdropped,
TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i]));
}
}
}
void
ip_drain(void)
{
VNET_ITERATOR_DECL(vnet_iter);
VNET_LIST_RLOCK_NOSLEEP();
IPQ_LOCK();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
ip_drain_locked();
CURVNET_RESTORE();
}
IPQ_UNLOCK();
VNET_LIST_RUNLOCK_NOSLEEP();
in_rtqdrain();
}
/*
* The protocol to be inserted into ip_protox[] must be already registered
* in inetsw[], either statically or through pf_proto_register().
*/
int
ipproto_register(short ipproto)
{
struct protosw *pr;
/* Sanity checks. */
if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
return (EPROTONOSUPPORT);
/*
* The protocol slot must not be occupied by another protocol
* already. An index pointing to IPPROTO_RAW is unused.
*/
pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == NULL)
return (EPFNOSUPPORT);
if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */
return (EEXIST);
/* Find the protocol position in inetsw[] and set the index. */
for (pr = inetdomain.dom_protosw;
pr < inetdomain.dom_protoswNPROTOSW; pr++) {
if (pr->pr_domain->dom_family == PF_INET &&
pr->pr_protocol && pr->pr_protocol == ipproto) {
ip_protox[pr->pr_protocol] = pr - inetsw;
return (0);
}
}
return (EPROTONOSUPPORT);
}
int
ipproto_unregister(short ipproto)
{
struct protosw *pr;
/* Sanity checks. */
if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
return (EPROTONOSUPPORT);
/* Check if the protocol was indeed registered. */
pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == NULL)
return (EPFNOSUPPORT);
if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */
return (ENOENT);
/* Reset the protocol slot to IPPROTO_RAW. */
ip_protox[ipproto] = pr - inetsw;
return (0);
}
/*
* Given address of next destination (final or next hop), return (referenced)
* internet address info of interface to be used to get there.
*/
struct in_ifaddr *
ip_rtaddr(struct in_addr dst, u_int fibnum)
{
struct route sro;
struct sockaddr_in *sin;
struct in_ifaddr *ia;
bzero(&sro, sizeof(sro));
sin = (struct sockaddr_in *)&sro.ro_dst;
sin->sin_family = AF_INET;
sin->sin_len = sizeof(*sin);
sin->sin_addr = dst;
in_rtalloc_ign(&sro, 0, fibnum);
if (sro.ro_rt == NULL)
return (NULL);
ia = ifatoia(sro.ro_rt->rt_ifa);
ifa_ref(&ia->ia_ifa);
RTFREE(sro.ro_rt);
return (ia);
}
u_char inetctlerrmap[PRC_NCMDS] = {
0, 0, 0, 0,
0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
EMSGSIZE, EHOSTUNREACH, 0, 0,
0, 0, EHOSTUNREACH, 0,
ENOPROTOOPT, ECONNREFUSED
};
/*
* Forward a packet. If some error occurs return the sender
* an icmp packet. Note we can't always generate a meaningful
* icmp message because icmp doesn't have a large enough repertoire
* of codes and types.
*
* If not forwarding, just drop the packet. This could be confusing
* if ipforwarding was zero but some routing protocol was advancing
* us as a gateway to somewhere. However, we must let the routing
* protocol deal with that.
*
* The srcrt parameter indicates whether the packet is being forwarded
* via a source route.
*/
void
ip_forward(struct mbuf *m, int srcrt)
{
struct ip *ip = mtod(m, struct ip *);
struct in_ifaddr *ia;
struct mbuf *mcopy;
struct in_addr dest;
struct route ro;
int error, type = 0, code = 0, mtu = 0;
if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
IPSTAT_INC(ips_cantforward);
m_freem(m);
return;
}
#ifdef IPSTEALTH
if (!V_ipstealth) {
#endif
if (ip->ip_ttl <= IPTTLDEC) {
icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
0, 0);
return;
}
#ifdef IPSTEALTH
}
#endif
ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
#ifndef IPSEC
/*
* 'ia' may be NULL if there is no route for this destination.
* In case of IPsec, Don't discard it just yet, but pass it to
* ip_output in case of outgoing IPsec policy.
*/
if (!srcrt && ia == NULL) {
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
return;
}
#endif
/*
* Save the IP header and at most 8 bytes of the payload,
* in case we need to generate an ICMP message to the src.
*
* XXX this can be optimized a lot by saving the data in a local
* buffer on the stack (72 bytes at most), and only allocating the
* mbuf if really necessary. The vast majority of the packets
* are forwarded without having to send an ICMP back (either
* because unnecessary, or because rate limited), so we are
* really we are wasting a lot of work here.
*
* We don't use m_copy() because it might return a reference
* to a shared cluster. Both this function and ip_output()
* assume exclusive access to the IP header in `m', so any
* data in a cluster may change before we reach icmp_error().
*/
mcopy = m_gethdr(M_NOWAIT, m->m_type);
if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_NOWAIT)) {
/*
* It's probably ok if the pkthdr dup fails (because
* the deep copy of the tag chain failed), but for now
* be conservative and just discard the copy since
* code below may some day want the tags.
*/
m_free(mcopy);
mcopy = NULL;
}
if (mcopy != NULL) {
mcopy->m_len = min(ntohs(ip->ip_len), M_TRAILINGSPACE(mcopy));
mcopy->m_pkthdr.len = mcopy->m_len;
m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
}
#ifdef IPSTEALTH
if (!V_ipstealth) {
#endif
ip->ip_ttl -= IPTTLDEC;
#ifdef IPSTEALTH
}
#endif
/*
* If forwarding packet using same interface that it came in on,
* perhaps should send a redirect to sender to shortcut a hop.
* Only send redirect if source is sending directly to us,
* and if packet was not source routed (or has any options).
* Also, don't send redirect if forwarding using a default route
* or a route modified by a redirect.
*/
dest.s_addr = 0;
if (!srcrt && V_ipsendredirects &&
ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) {
struct sockaddr_in *sin;
struct rtentry *rt;
bzero(&ro, sizeof(ro));
sin = (struct sockaddr_in *)&ro.ro_dst;
sin->sin_family = AF_INET;
sin->sin_len = sizeof(*sin);
sin->sin_addr = ip->ip_dst;
in_rtalloc_ign(&ro, 0, M_GETFIB(m));
rt = ro.ro_rt;
if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
satosin(rt_key(rt))->sin_addr.s_addr != 0) {
#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
u_long src = ntohl(ip->ip_src.s_addr);
if (RTA(rt) &&
(src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
if (rt->rt_flags & RTF_GATEWAY)
dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr;
else
dest.s_addr = ip->ip_dst.s_addr;
/* Router requirements says to only send host redirects */
type = ICMP_REDIRECT;
code = ICMP_REDIRECT_HOST;
}
}
if (rt)
RTFREE(rt);
}
/*
* Try to cache the route MTU from ip_output so we can consider it for
* the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191.
*/
bzero(&ro, sizeof(ro));
error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL);
if (error == EMSGSIZE && ro.ro_rt)
mtu = ro.ro_rt->rt_rmx.rmx_mtu;
RO_RTFREE(&ro);
if (error)
IPSTAT_INC(ips_cantforward);
else {
IPSTAT_INC(ips_forward);
if (type)
IPSTAT_INC(ips_redirectsent);
else {
if (mcopy)
m_freem(mcopy);
if (ia != NULL)
ifa_free(&ia->ia_ifa);
return;
}
}
if (mcopy == NULL) {
if (ia != NULL)
ifa_free(&ia->ia_ifa);
return;
}
switch (error) {
case 0: /* forwarded, but need redirect */
/* type, code set above */
break;
case ENETUNREACH:
case EHOSTUNREACH:
case ENETDOWN:
case EHOSTDOWN:
default:
type = ICMP_UNREACH;
code = ICMP_UNREACH_HOST;
break;
case EMSGSIZE:
type = ICMP_UNREACH;
code = ICMP_UNREACH_NEEDFRAG;
#ifdef IPSEC
/*
* If IPsec is configured for this path,
* override any possibly mtu value set by ip_output.
*/
mtu = ip_ipsec_mtu(mcopy, mtu);
#endif /* IPSEC */
/*
* If the MTU was set before make sure we are below the
* interface MTU.
* If the MTU wasn't set before use the interface mtu or
* fall back to the next smaller mtu step compared to the
* current packet size.
*/
if (mtu != 0) {
if (ia != NULL)
mtu = min(mtu, ia->ia_ifp->if_mtu);
} else {
if (ia != NULL)
mtu = ia->ia_ifp->if_mtu;
else
mtu = ip_next_mtu(ntohs(ip->ip_len), 0);
}
IPSTAT_INC(ips_cantfrag);
break;
case ENOBUFS:
/*
* A router should not generate ICMP_SOURCEQUENCH as
* required in RFC1812 Requirements for IP Version 4 Routers.
* Source quench could be a big problem under DoS attacks,
* or if the underlying interface is rate-limited.
* Those who need source quench packets may re-enable them
* via the net.inet.ip.sendsourcequench sysctl.
*/
if (V_ip_sendsourcequench == 0) {
m_freem(mcopy);
if (ia != NULL)
ifa_free(&ia->ia_ifa);
return;
} else {
type = ICMP_SOURCEQUENCH;
code = 0;
}
break;
case EACCES: /* ipfw denied packet */
m_freem(mcopy);
if (ia != NULL)
ifa_free(&ia->ia_ifa);
return;
}
if (ia != NULL)
ifa_free(&ia->ia_ifa);
icmp_error(mcopy, type, code, dest.s_addr, mtu);
}
void
ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
struct mbuf *m)
{
if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) {
struct bintime bt;
bintime(&bt);
if (inp->inp_socket->so_options & SO_BINTIME) {
*mp = sbcreatecontrol((caddr_t)&bt, sizeof(bt),
SCM_BINTIME, SOL_SOCKET);
if (*mp)
mp = &(*mp)->m_next;
}
if (inp->inp_socket->so_options & SO_TIMESTAMP) {
struct timeval tv;
bintime2timeval(&bt, &tv);
*mp = sbcreatecontrol((caddr_t)&tv, sizeof(tv),
SCM_TIMESTAMP, SOL_SOCKET);
if (*mp)
mp = &(*mp)->m_next;
}
}
if (inp->inp_flags & INP_RECVDSTADDR) {
*mp = sbcreatecontrol((caddr_t)&ip->ip_dst,
sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
if (inp->inp_flags & INP_RECVTTL) {
*mp = sbcreatecontrol((caddr_t)&ip->ip_ttl,
sizeof(u_char), IP_RECVTTL, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
#ifdef notyet
/* XXX
* Moving these out of udp_input() made them even more broken
* than they already were.
*/
/* options were tossed already */
if (inp->inp_flags & INP_RECVOPTS) {
*mp = sbcreatecontrol((caddr_t)opts_deleted_above,
sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
/* ip_srcroute doesn't do what we want here, need to fix */
if (inp->inp_flags & INP_RECVRETOPTS) {
*mp = sbcreatecontrol((caddr_t)ip_srcroute(m),
sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
#endif
if (inp->inp_flags & INP_RECVIF) {
struct ifnet *ifp;
struct sdlbuf {
struct sockaddr_dl sdl;
u_char pad[32];
} sdlbuf;
struct sockaddr_dl *sdp;
struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
if ((ifp = m->m_pkthdr.rcvif) &&
ifp->if_index && ifp->if_index <= V_if_index) {
sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr;
/*
* Change our mind and don't try copy.
*/
if (sdp->sdl_family != AF_LINK ||
sdp->sdl_len > sizeof(sdlbuf)) {
goto makedummy;
}
bcopy(sdp, sdl2, sdp->sdl_len);
} else {
makedummy:
sdl2->sdl_len =
offsetof(struct sockaddr_dl, sdl_data[0]);
sdl2->sdl_family = AF_LINK;
sdl2->sdl_index = 0;
sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
}
*mp = sbcreatecontrol((caddr_t)sdl2, sdl2->sdl_len,
IP_RECVIF, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
if (inp->inp_flags & INP_RECVTOS) {
*mp = sbcreatecontrol((caddr_t)&ip->ip_tos,
sizeof(u_char), IP_RECVTOS, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
}
/*
* XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the
* ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on
* locking. This code remains in ip_input.c as ip_mroute.c is optionally
* compiled.
*/
static VNET_DEFINE(int, ip_rsvp_on);
VNET_DEFINE(struct socket *, ip_rsvpd);
#define V_ip_rsvp_on VNET(ip_rsvp_on)
int
ip_rsvp_init(struct socket *so)
{
if (so->so_type != SOCK_RAW ||
so->so_proto->pr_protocol != IPPROTO_RSVP)
return EOPNOTSUPP;
if (V_ip_rsvpd != NULL)
return EADDRINUSE;
V_ip_rsvpd = so;
/*
* This may seem silly, but we need to be sure we don't over-increment
* the RSVP counter, in case something slips up.
*/
if (!V_ip_rsvp_on) {
V_ip_rsvp_on = 1;
V_rsvp_on++;
}
return 0;
}
int
ip_rsvp_done(void)
{
V_ip_rsvpd = NULL;
/*
* This may seem silly, but we need to be sure we don't over-decrement
* the RSVP counter, in case something slips up.
*/
if (V_ip_rsvp_on) {
V_ip_rsvp_on = 0;
V_rsvp_on--;
}
return 0;
}
void
rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */
{
if (rsvp_input_p) { /* call the real one if loaded */
rsvp_input_p(m, off);
return;
}
/* Can still get packets with rsvp_on = 0 if there is a local member
* of the group to which the RSVP packet is addressed. But in this
* case we want to throw the packet away.
*/
if (!V_rsvp_on) {
m_freem(m);
return;
}
if (V_ip_rsvpd != NULL) {
rip_input(m, off);
return;
}
/* Drop the packet */
m_freem(m);
}
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