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mirror of https://git.FreeBSD.org/src.git synced 2024-12-23 11:18:54 +00:00
freebsd/usr.sbin/ppp/ip.c
Brian Somers a272e47d50 Understand networks in the filter rules. We don't
insist on x.x.x.0/24 - x.x.x.x/24 is ok too.
1997-11-12 21:04:21 +00:00

504 lines
12 KiB
C

/*
* PPP IP Protocol Interface
*
* Written by Toshiharu OHNO (tony-o@iij.ad.jp)
*
* Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the Internet Initiative Japan. The name of the
* IIJ may not 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 MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* $Id: ip.c,v 1.28 1997/11/12 19:48:45 brian Exp $
*
* TODO:
* o Return ICMP message for filterd packet
* and optionaly record it into log.
*/
#include <sys/param.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/udp.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <alias.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include "mbuf.h"
#include "log.h"
#include "defs.h"
#include "timer.h"
#include "fsm.h"
#include "lcpproto.h"
#include "hdlc.h"
#include "loadalias.h"
#include "command.h"
#include "vars.h"
#include "filter.h"
#include "log.h"
#include "os.h"
#include "ipcp.h"
#include "vjcomp.h"
#include "lcp.h"
#include "modem.h"
#include "ip.h"
static struct pppTimer IdleTimer;
static void
IdleTimeout()
{
LogPrintf(LogPHASE, "Idle timer expired.\n");
reconnect(RECON_FALSE);
LcpClose();
}
/*
* Start Idle timer. If timeout is reached, we call LcpClose() to
* close LCP and link.
*/
void
StartIdleTimer()
{
if (!(mode & (MODE_DEDICATED | MODE_DDIAL))) {
StopTimer(&IdleTimer);
IdleTimer.func = IdleTimeout;
IdleTimer.load = VarIdleTimeout * SECTICKS;
IdleTimer.state = TIMER_STOPPED;
StartTimer(&IdleTimer);
}
}
void
UpdateIdleTimer()
{
if (OsLinkIsUp())
StartIdleTimer();
}
void
StopIdleTimer()
{
StopTimer(&IdleTimer);
}
/*
* If any IP layer traffic is detected, refresh IdleTimer.
*/
static void
RestartIdleTimer()
{
if (!(mode & (MODE_DEDICATED | MODE_DDIAL)) && ipKeepAlive) {
StartTimer(&IdleTimer);
ipIdleSecs = 0;
}
}
static u_short interactive_ports[32] = {
544, 513, 514, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 21, 22, 23, 0, 0, 0, 0, 0, 0, 0, 543,
};
#define INTERACTIVE(p) (interactive_ports[(p) & 0x1F] == (p))
static char *TcpFlags[] = {
"FIN", "SYN", "RST", "PSH", "ACK", "URG",
};
static char *Direction[] = {"INP", "OUT", "OUT", "IN/OUT"};
static struct filterent *Filters[] = {ifilters, ofilters, dfilters, afilters};
static int
PortMatch(int op, u_short pport, u_short rport)
{
switch (op) {
case OP_EQ:
return (pport == rport);
case OP_GT:
return (pport > rport);
case OP_LT:
return (pport < rport);
default:
return (0);
}
}
/*
* Check a packet against with defined filters
*/
static int
FilterCheck(struct ip * pip, int direction)
{
struct filterent *fp = Filters[direction];
int gotinfo, cproto, estab, n;
struct tcphdr *th;
struct udphdr *uh;
struct icmp *ih;
char *ptop;
u_short sport, dport;
if (fp->action) {
cproto = gotinfo = estab = 0;
sport = dport = 0;
for (n = 0; n < MAXFILTERS; n++) {
if (fp->action) {
/* permit fragments on in and out filter */
if ((direction == FL_IN || direction == FL_OUT) &&
(ntohs(pip->ip_off) & IP_OFFMASK) != 0) {
return (A_PERMIT);
}
LogPrintf(LogDEBUG, "rule = %d\n", n);
if ((pip->ip_src.s_addr & fp->smask.s_addr) ==
(fp->saddr.s_addr & fp->smask.s_addr) &&
(pip->ip_dst.s_addr & fp->dmask.s_addr) ==
(fp->daddr.s_addr & fp->dmask.s_addr)) {
if (fp->proto) {
if (!gotinfo) {
ptop = (char *) pip + (pip->ip_hl << 2);
switch (pip->ip_p) {
case IPPROTO_ICMP:
cproto = P_ICMP;
ih = (struct icmp *) ptop;
sport = ih->icmp_type;
estab = 1;
break;
case IPPROTO_UDP:
cproto = P_UDP;
uh = (struct udphdr *) ptop;
sport = ntohs(uh->uh_sport);
dport = ntohs(uh->uh_dport);
estab = 1;
break;
case IPPROTO_TCP:
cproto = P_TCP;
th = (struct tcphdr *) ptop;
sport = ntohs(th->th_sport);
dport = ntohs(th->th_dport);
estab = (th->th_flags & TH_ACK);
if (estab == 0)
LogPrintf(LogDEBUG, "flag = %02x, sport = %d, dport = %d\n",
th->th_flags, sport, dport);
break;
default:
return (A_DENY);/* We'll block unknown type of packet */
}
gotinfo = 1;
LogPrintf(LogDEBUG, "dir = %d, proto = %d, srcop = %d,"
" dstop = %d, estab = %d\n", direction, cproto,
fp->opt.srcop, fp->opt.dstop, estab);
}
LogPrintf(LogDEBUG, "check0: rule = %d, proto = %d, sport = %d,"
" dport = %d\n", n, cproto, sport, dport);
LogPrintf(LogDEBUG, "check0: action = %d\n", fp->action);
if (cproto == fp->proto) {
if ((fp->opt.srcop == OP_NONE ||
PortMatch(fp->opt.srcop, sport, fp->opt.srcport))
&&
(fp->opt.dstop == OP_NONE ||
PortMatch(fp->opt.dstop, dport, fp->opt.dstport))
&&
(fp->opt.estab == 0 || estab)) {
return (fp->action);
}
}
} else {
/* Address is mached. Make a decision. */
LogPrintf(LogDEBUG, "check1: action = %d\n", fp->action);
return (fp->action);
}
}
}
fp++;
}
return (A_DENY); /* No rule is mached. Deny this packet */
}
return (A_PERMIT); /* No rule is given. Permit this packet */
}
static void
IcmpError(struct ip * pip, int code)
{
#ifdef notdef
struct mbuf *bp;
if (pip->ip_p != IPPROTO_ICMP) {
bp = mballoc(cnt, MB_IPIN);
memcpy(MBUF_CTOP(bp), ptr, cnt);
SendPppFrame(bp);
RestartIdleTimer();
ipOutOctets += cnt;
}
#endif
}
/*
* For debugging aid.
*/
int
PacketCheck(char *cp, int nb, int direction)
{
struct ip *pip;
struct tcphdr *th;
struct udphdr *uh;
struct icmp *icmph;
char *ptop;
int mask, len, n;
int pri = PRI_NORMAL;
int logit, loglen;
static char logbuf[200];
logit = LogIsKept(LogTCPIP);
loglen = 0;
pip = (struct ip *) cp;
if (logit && loglen < sizeof logbuf) {
snprintf(logbuf + loglen, sizeof logbuf - loglen, "%s ",
Direction[direction]);
loglen += strlen(logbuf + loglen);
}
ptop = (cp + (pip->ip_hl << 2));
switch (pip->ip_p) {
case IPPROTO_ICMP:
if (logit && loglen < sizeof logbuf) {
icmph = (struct icmp *) ptop;
snprintf(logbuf + loglen, sizeof logbuf - loglen,
"ICMP: %s:%d ---> ", inet_ntoa(pip->ip_src), icmph->icmp_type);
loglen += strlen(logbuf + loglen);
snprintf(logbuf + loglen, sizeof logbuf - loglen,
"%s:%d", inet_ntoa(pip->ip_dst), icmph->icmp_type);
loglen += strlen(logbuf + loglen);
}
break;
case IPPROTO_UDP:
if (logit && loglen < sizeof logbuf) {
uh = (struct udphdr *) ptop;
snprintf(logbuf + loglen, sizeof logbuf - loglen,
"UDP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport));
loglen += strlen(logbuf + loglen);
snprintf(logbuf + loglen, sizeof logbuf - loglen,
"%s:%d", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport));
loglen += strlen(logbuf + loglen);
}
break;
case IPPROTO_TCP:
th = (struct tcphdr *) ptop;
if (pip->ip_tos == IPTOS_LOWDELAY)
pri = PRI_FAST;
else if ((ntohs(pip->ip_off) & IP_OFFMASK) == 0) {
if (INTERACTIVE(ntohs(th->th_sport)) || INTERACTIVE(ntohs(th->th_dport)))
pri = PRI_FAST;
}
if (logit && loglen < sizeof logbuf) {
len = ntohs(pip->ip_len) - (pip->ip_hl << 2) - (th->th_off << 2);
snprintf(logbuf + loglen, sizeof logbuf - loglen,
"TCP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(th->th_sport));
loglen += strlen(logbuf + loglen);
snprintf(logbuf + loglen, sizeof logbuf - loglen,
"%s:%d", inet_ntoa(pip->ip_dst), ntohs(th->th_dport));
loglen += strlen(logbuf + loglen);
n = 0;
for (mask = TH_FIN; mask != 0x40; mask <<= 1) {
if (th->th_flags & mask) {
snprintf(logbuf + loglen, sizeof logbuf - loglen, " %s", TcpFlags[n]);
loglen += strlen(logbuf + loglen);
}
n++;
}
snprintf(logbuf + loglen, sizeof logbuf - loglen,
" seq:%x ack:%x (%d/%d)",
ntohl(th->th_seq), ntohl(th->th_ack), len, nb);
loglen += strlen(logbuf + loglen);
if ((th->th_flags & TH_SYN) && nb > 40) {
u_short *sp;
ptop += 20;
sp = (u_short *) ptop;
if (ntohs(sp[0]) == 0x0204) {
snprintf(logbuf + loglen, sizeof logbuf - loglen,
" MSS = %d", ntohs(sp[1]));
loglen += strlen(logbuf + loglen);
}
}
}
break;
}
if ((FilterCheck(pip, direction) & A_DENY)) {
if (logit)
LogPrintf(LogTCPIP, "%s - BLOCKED\n", logbuf);
if (direction == 0)
IcmpError(pip, pri);
return (-1);
} else {
if (FilterCheck(pip, FL_KEEP) & A_DENY) { /* Check Keep Alive filter */
if (logit)
LogPrintf(LogTCPIP, "%s - NO KEEPALIVE\n", logbuf);
ipKeepAlive = 0;
} else {
if (logit)
LogPrintf(LogTCPIP, "%s\n", logbuf);
ipKeepAlive = 1;
}
return (pri);
}
}
void
IpInput(struct mbuf * bp)
{ /* IN: Pointer to IP pakcet */
u_char *cp;
struct mbuf *wp;
int nb, nw;
u_char tunbuff[MAX_MRU];
cp = tunbuff;
nb = 0;
for (wp = bp; wp; wp = wp->next) { /* Copy to contiguous region */
memcpy(cp, MBUF_CTOP(wp), wp->cnt);
cp += wp->cnt;
nb += wp->cnt;
}
if (mode & MODE_ALIAS) {
int iresult;
char *fptr;
iresult = VarPacketAliasIn(tunbuff, sizeof tunbuff);
nb = ntohs(((struct ip *) tunbuff)->ip_len);
if (nb > MAX_MRU) {
LogPrintf(LogERROR, "IpInput: Problem with IP header length\n");
pfree(bp);
return;
}
if (iresult == PKT_ALIAS_OK
|| iresult == PKT_ALIAS_FOUND_HEADER_FRAGMENT) {
if (PacketCheck(tunbuff, nb, FL_IN) < 0) {
pfree(bp);
return;
}
ipInOctets += nb;
nb = ntohs(((struct ip *) tunbuff)->ip_len);
nw = write(tun_out, tunbuff, nb);
if (nw != nb)
if (nw == -1)
LogPrintf(LogERROR, "IpInput: wrote %d, got %s\n", nb,
strerror(errno));
else
LogPrintf(LogERROR, "IpInput: wrote %d, got %d\n", nb, nw);
if (iresult == PKT_ALIAS_FOUND_HEADER_FRAGMENT) {
while ((fptr = VarPacketAliasGetFragment(tunbuff)) != NULL) {
VarPacketAliasFragmentIn(tunbuff, fptr);
nb = ntohs(((struct ip *) fptr)->ip_len);
nw = write(tun_out, fptr, nb);
if (nw != nb)
if (nw == -1)
LogPrintf(LogERROR, "IpInput: wrote %d, got %s\n", nb,
strerror(errno));
else
LogPrintf(LogERROR, "IpInput: wrote %d, got %d\n", nb, nw);
free(fptr);
}
}
} else if (iresult == PKT_ALIAS_UNRESOLVED_FRAGMENT) {
nb = ntohs(((struct ip *) tunbuff)->ip_len);
fptr = malloc(nb);
if (fptr == NULL)
LogPrintf(LogALERT, "IpInput: Cannot allocate memory for fragment\n");
else {
memcpy(fptr, tunbuff, nb);
VarPacketAliasSaveFragment(fptr);
}
}
} else { /* no aliasing */
if (PacketCheck(tunbuff, nb, FL_IN) < 0) {
pfree(bp);
return;
}
ipInOctets += nb;
nw = write(tun_out, tunbuff, nb);
if (nw != nb)
if (nw == -1)
LogPrintf(LogERROR, "IpInput: wrote %d, got %s\n", nb, strerror(errno));
else
LogPrintf(LogERROR, "IpInput: wrote %d, got %d\n", nb, nw);
}
pfree(bp);
RestartIdleTimer();
}
static struct mqueue IpOutputQueues[PRI_FAST + 1];
void
IpEnqueue(int pri, char *ptr, int count)
{
struct mbuf *bp;
bp = mballoc(count, MB_IPQ);
memcpy(MBUF_CTOP(bp), ptr, count);
Enqueue(&IpOutputQueues[pri], bp);
}
#if 0
int
IsIpEnqueued()
{
struct mqueue *queue;
int exist = 0;
for (queue = &IpOutputQueues[PRI_FAST]; queue >= IpOutputQueues; queue--) {
if (queue->qlen > 0) {
exist = 1;
break;
}
}
return (exist);
}
#endif
void
IpStartOutput()
{
struct mqueue *queue;
struct mbuf *bp;
int cnt;
if (IpcpFsm.state != ST_OPENED)
return;
for (queue = &IpOutputQueues[PRI_FAST]; queue >= IpOutputQueues; queue--) {
if (queue->top) {
bp = Dequeue(queue);
if (bp) {
cnt = plength(bp);
SendPppFrame(bp);
RestartIdleTimer();
ipOutOctets += cnt;
break;
}
}
}
}