ip.c revision 39395 
1/*
2 *		PPP IP Protocol Interface
3 *
4 *	    Written by Toshiharu OHNO (tony-o@iij.ad.jp)
5 *
6 *   Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
7 *
8 * Redistribution and use in source and binary forms are permitted
9 * provided that the above copyright notice and this paragraph are
10 * duplicated in all such forms and that any documentation,
11 * advertising materials, and other materials related to such
12 * distribution and use acknowledge that the software was developed
13 * by the Internet Initiative Japan.  The name of the
14 * IIJ may not be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19 *
20 * $Id: ip.c,v 1.52 1998/08/26 17:39:37 brian Exp $
21 *
22 *	TODO:
23 *		o Return ICMP message for filterd packet
24 *		  and optionaly record it into log.
25 */
26#include <sys/types.h>
27#ifdef __OpenBSD__
28#include <sys/socket.h>
29#endif
30#include <netinet/in.h>
31#include <netinet/in_systm.h>
32#include <netinet/ip.h>
33#include <netinet/ip_icmp.h>
34#include <netinet/udp.h>
35#include <netinet/tcp.h>
36#include <arpa/inet.h>
37#include <sys/un.h>
38
39#include <errno.h>
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <unistd.h>
44
45#ifndef NOALIAS
46#ifdef __OpenBSD__
47#include "alias.h"
48#else
49#include <alias.h>
50#endif
51#endif
52#include "mbuf.h"
53#include "log.h"
54#include "defs.h"
55#include "timer.h"
56#include "fsm.h"
57#include "lqr.h"
58#include "hdlc.h"
59#include "throughput.h"
60#include "iplist.h"
61#include "slcompress.h"
62#include "ipcp.h"
63#include "filter.h"
64#include "descriptor.h"
65#include "lcp.h"
66#include "ccp.h"
67#include "link.h"
68#include "mp.h"
69#include "bundle.h"
70#include "vjcomp.h"
71#include "tun.h"
72#include "ip.h"
73
74static const u_short interactive_ports[32] = {
75  544, 513, 514, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
76  0, 0, 0, 0, 0, 21, 22, 23, 0, 0, 0, 0, 0, 0, 0, 543,
77};
78
79#define	INTERACTIVE(p)	(interactive_ports[(p) & 0x1F] == (p))
80
81static const char *TcpFlags[] = { "FIN", "SYN", "RST", "PSH", "ACK", "URG" };
82
83static int
84PortMatch(int op, u_short pport, u_short rport)
85{
86  switch (op) {
87    case OP_EQ:
88    return (pport == rport);
89  case OP_GT:
90    return (pport > rport);
91  case OP_LT:
92    return (pport < rport);
93  default:
94    return (0);
95  }
96}
97
98/*
99 *  Check a packet against with defined filters
100 */
101static int
102FilterCheck(struct ip *pip, struct filter *filter)
103{
104  int gotinfo, cproto, estab, syn, finrst, n, len, didname;
105  struct tcphdr *th;
106  struct udphdr *uh;
107  struct icmp *ih;
108  char *ptop;
109  u_short sport, dport;
110  struct filterent *fp = filter->rule;
111  char dbuff[100];
112
113  if (fp->action) {
114    cproto = gotinfo = estab = syn = finrst = didname = 0;
115    sport = dport = 0;
116    for (n = 0; n < MAXFILTERS; n++) {
117      if (fp->action) {
118	/* permit fragments on in and out filter */
119        if (filter->fragok && (ntohs(pip->ip_off) & IP_OFFMASK) != 0)
120	  return (A_PERMIT);
121
122        if (!didname)
123          log_Printf(LogDEBUG, "%s filter:\n", filter->name);
124        didname = 1;
125
126	if ((pip->ip_src.s_addr & fp->smask.s_addr) ==
127	    (fp->saddr.s_addr & fp->smask.s_addr) &&
128	    (pip->ip_dst.s_addr & fp->dmask.s_addr) ==
129	    (fp->daddr.s_addr & fp->dmask.s_addr)) {
130	  if (fp->proto) {
131	    if (!gotinfo) {
132	      ptop = (char *) pip + (pip->ip_hl << 2);
133
134	      switch (pip->ip_p) {
135	      case IPPROTO_ICMP:
136		cproto = P_ICMP;
137		ih = (struct icmp *) ptop;
138		sport = ih->icmp_type;
139		estab = syn = finrst = -1;
140                if (log_IsKept(LogDEBUG))
141		  snprintf(dbuff, sizeof dbuff, "sport = %d", sport);
142		break;
143	      case IPPROTO_UDP:
144	      case IPPROTO_IGMP:
145	      case IPPROTO_IPIP:
146		cproto = P_UDP;
147		uh = (struct udphdr *) ptop;
148		sport = ntohs(uh->uh_sport);
149		dport = ntohs(uh->uh_dport);
150		estab = syn = finrst = -1;
151                if (log_IsKept(LogDEBUG))
152		  snprintf(dbuff, sizeof dbuff, "sport = %d, dport = %d",
153                           sport, dport);
154		break;
155	      case IPPROTO_TCP:
156		cproto = P_TCP;
157		th = (struct tcphdr *) ptop;
158		sport = ntohs(th->th_sport);
159		dport = ntohs(th->th_dport);
160		estab = (th->th_flags & TH_ACK);
161		syn = (th->th_flags & TH_SYN);
162		finrst = (th->th_flags & (TH_FIN|TH_RST));
163                if (log_IsKept(LogDEBUG) && !estab)
164		  snprintf(dbuff, sizeof dbuff,
165                           "flags = %02x, sport = %d, dport = %d",
166                           th->th_flags, sport, dport);
167		break;
168	      default:
169		return (A_DENY);       /* We'll block unknown type of packet */
170	      }
171              if (log_IsKept(LogDEBUG)) {
172                if (estab != -1) {
173                  len = strlen(dbuff);
174                  snprintf(dbuff + len, sizeof dbuff - len,
175                           ", estab = %d, syn = %d, finrst = %d",
176                           estab, syn, finrst);
177                }
178	        log_Printf(LogDEBUG, " Filter: proto = %s, %s\n",
179                          filter_Proto2Nam(cproto), dbuff);
180              }
181	      gotinfo = 1;
182	    }
183            if (log_IsKept(LogDEBUG)) {
184	      if (fp->opt.srcop != OP_NONE) {
185                snprintf(dbuff, sizeof dbuff, ", src %s %d",
186                         filter_Op2Nam(fp->opt.srcop), fp->opt.srcport);
187                len = strlen(dbuff);
188              } else
189                len = 0;
190	      if (fp->opt.dstop != OP_NONE) {
191                snprintf(dbuff + len, sizeof dbuff - len,
192                         ", dst %s %d", filter_Op2Nam(fp->opt.dstop),
193                         fp->opt.dstport);
194              } else if (!len)
195                *dbuff = '\0';
196
197	      log_Printf(LogDEBUG, "  rule = %d: Address match, "
198                        "check against proto %s%s, action = %s\n",
199                        n, filter_Proto2Nam(fp->proto),
200                        dbuff, filter_Action2Nam(fp->action));
201            }
202
203	    if (cproto == fp->proto) {
204	      if ((fp->opt.srcop == OP_NONE ||
205		   PortMatch(fp->opt.srcop, sport, fp->opt.srcport)) &&
206		  (fp->opt.dstop == OP_NONE ||
207		   PortMatch(fp->opt.dstop, dport, fp->opt.dstport)) &&
208		  (fp->opt.estab == 0 || estab) &&
209		  (fp->opt.syn == 0 || syn) &&
210		  (fp->opt.finrst == 0 || finrst)) {
211		return (fp->action);
212	      }
213	    }
214	  } else {
215	    /* Address is mached. Make a decision. */
216	    log_Printf(LogDEBUG, "  rule = %d: Address match, action = %s\n", n,
217                      filter_Action2Nam(fp->action));
218	    return (fp->action);
219	  }
220	} else
221	  log_Printf(LogDEBUG, "  rule = %d: Address mismatch\n", n);
222      }
223      fp++;
224    }
225    return (A_DENY);		/* No rule is mached. Deny this packet */
226  }
227  return (A_PERMIT);		/* No rule is given. Permit this packet */
228}
229
230#ifdef notdef
231static void
232IcmpError(struct ip * pip, int code)
233{
234  struct mbuf *bp;
235
236  if (pip->ip_p != IPPROTO_ICMP) {
237    bp = mbuf_Alloc(cnt, MB_IPIN);
238    memcpy(MBUF_CTOP(bp), ptr, cnt);
239    vj_SendFrame(bp);
240    ipcp_AddOutOctets(cnt);
241  }
242}
243#endif
244
245/*
246 *  For debugging aid.
247 */
248int
249PacketCheck(struct bundle *bundle, char *cp, int nb, struct filter *filter)
250{
251  struct ip *pip;
252  struct tcphdr *th;
253  struct udphdr *uh;
254  struct icmp *icmph;
255  char *ptop;
256  int mask, len, n;
257  int pri = PRI_NORMAL;
258  int logit, loglen;
259  char logbuf[200];
260
261  logit = log_IsKept(LogTCPIP) && filter->logok;
262  loglen = 0;
263
264  pip = (struct ip *) cp;
265
266  if (logit && loglen < sizeof logbuf) {
267    snprintf(logbuf + loglen, sizeof logbuf - loglen, "%s ", filter->name);
268    loglen += strlen(logbuf + loglen);
269  }
270  ptop = (cp + (pip->ip_hl << 2));
271
272  switch (pip->ip_p) {
273  case IPPROTO_ICMP:
274    if (logit && loglen < sizeof logbuf) {
275      icmph = (struct icmp *) ptop;
276      snprintf(logbuf + loglen, sizeof logbuf - loglen,
277	     "ICMP: %s:%d ---> ", inet_ntoa(pip->ip_src), icmph->icmp_type);
278      loglen += strlen(logbuf + loglen);
279      snprintf(logbuf + loglen, sizeof logbuf - loglen,
280	       "%s:%d", inet_ntoa(pip->ip_dst), icmph->icmp_type);
281      loglen += strlen(logbuf + loglen);
282    }
283    break;
284  case IPPROTO_UDP:
285    if (logit && loglen < sizeof logbuf) {
286      uh = (struct udphdr *) ptop;
287      snprintf(logbuf + loglen, sizeof logbuf - loglen,
288	   "UDP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport));
289      loglen += strlen(logbuf + loglen);
290      snprintf(logbuf + loglen, sizeof logbuf - loglen,
291	       "%s:%d", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport));
292      loglen += strlen(logbuf + loglen);
293    }
294    break;
295  case IPPROTO_IPIP:
296    if (logit && loglen < sizeof logbuf) {
297      uh = (struct udphdr *) ptop;
298      snprintf(logbuf + loglen, sizeof logbuf - loglen,
299	   "IPIP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport));
300      loglen += strlen(logbuf + loglen);
301      snprintf(logbuf + loglen, sizeof logbuf - loglen,
302	       "%s:%d", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport));
303      loglen += strlen(logbuf + loglen);
304    }
305    break;
306  case IPPROTO_IGMP:
307    if (logit && loglen < sizeof logbuf) {
308      uh = (struct udphdr *) ptop;
309      snprintf(logbuf + loglen, sizeof logbuf - loglen,
310	   "IGMP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport));
311      loglen += strlen(logbuf + loglen);
312      snprintf(logbuf + loglen, sizeof logbuf - loglen,
313	       "%s:%d", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport));
314      loglen += strlen(logbuf + loglen);
315    }
316    break;
317  case IPPROTO_TCP:
318    th = (struct tcphdr *) ptop;
319    if (pip->ip_tos == IPTOS_LOWDELAY)
320      pri = PRI_FAST;
321    else if ((ntohs(pip->ip_off) & IP_OFFMASK) == 0) {
322      if (INTERACTIVE(ntohs(th->th_sport)) || INTERACTIVE(ntohs(th->th_dport)))
323	pri = PRI_FAST;
324    }
325    if (logit && loglen < sizeof logbuf) {
326      len = ntohs(pip->ip_len) - (pip->ip_hl << 2) - (th->th_off << 2);
327      snprintf(logbuf + loglen, sizeof logbuf - loglen,
328	   "TCP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(th->th_sport));
329      loglen += strlen(logbuf + loglen);
330      snprintf(logbuf + loglen, sizeof logbuf - loglen,
331	       "%s:%d", inet_ntoa(pip->ip_dst), ntohs(th->th_dport));
332      loglen += strlen(logbuf + loglen);
333      n = 0;
334      for (mask = TH_FIN; mask != 0x40; mask <<= 1) {
335	if (th->th_flags & mask) {
336	  snprintf(logbuf + loglen, sizeof logbuf - loglen, " %s", TcpFlags[n]);
337	  loglen += strlen(logbuf + loglen);
338	}
339	n++;
340      }
341      snprintf(logbuf + loglen, sizeof logbuf - loglen,
342	       "  seq:%lx  ack:%lx (%d/%d)",
343	       (u_long)ntohl(th->th_seq), (u_long)ntohl(th->th_ack), len, nb);
344      loglen += strlen(logbuf + loglen);
345      if ((th->th_flags & TH_SYN) && nb > 40) {
346	u_short *sp;
347
348	ptop += 20;
349	sp = (u_short *) ptop;
350	if (ntohs(sp[0]) == 0x0204) {
351	  snprintf(logbuf + loglen, sizeof logbuf - loglen,
352		   " MSS = %d", ntohs(sp[1]));
353	  loglen += strlen(logbuf + loglen);
354	}
355      }
356    }
357    break;
358  }
359
360  if ((FilterCheck(pip, filter) & A_DENY)) {
361    if (logit)
362      log_Printf(LogTCPIP, "%s - BLOCKED\n", logbuf);
363#ifdef notdef
364    if (direction == 0)
365      IcmpError(pip, pri);
366#endif
367    return (-1);
368  } else {
369    /* Check Keep Alive filter */
370    if (logit) {
371      if (FilterCheck(pip, &bundle->filter.alive) & A_DENY)
372        log_Printf(LogTCPIP, "%s - NO KEEPALIVE\n", logbuf);
373      else
374        log_Printf(LogTCPIP, "%s\n", logbuf);
375    }
376    return (pri);
377  }
378}
379
380void
381ip_Input(struct bundle *bundle, struct mbuf * bp)
382{
383  u_char *cp;
384  struct mbuf *wp;
385  int nb, nw;
386  struct tun_data tun;
387  struct ip *pip = (struct ip *)tun.data;
388#ifndef NOALIAS
389  struct ip *piip = (struct ip *)((char *)pip + (pip->ip_hl << 2));
390#endif
391
392  tun_fill_header(tun, AF_INET);
393  cp = tun.data;
394  nb = 0;
395  for (wp = bp; wp; wp = wp->next) {	/* Copy to contiguous region */
396    if (sizeof tun.data - (cp - tun.data) < wp->cnt) {
397      log_Printf(LogWARN, "ip_Input: Packet too large (%d) - dropped\n",
398                mbuf_Length(bp));
399      mbuf_Free(bp);
400      return;
401    }
402    memcpy(cp, MBUF_CTOP(wp), wp->cnt);
403    cp += wp->cnt;
404    nb += wp->cnt;
405  }
406
407#ifndef NOALIAS
408  if (bundle->AliasEnabled && pip->ip_p != IPPROTO_IGMP &&
409      (pip->ip_p != IPPROTO_IPIP || !IN_CLASSD(ntohl(piip->ip_dst.s_addr)))) {
410    struct tun_data *frag;
411    int iresult;
412    char *fptr;
413
414    iresult = PacketAliasIn(tun.data, sizeof tun.data);
415    nb = ntohs(((struct ip *) tun.data)->ip_len);
416
417    if (nb > MAX_MRU) {
418      log_Printf(LogWARN, "ip_Input: Problem with IP header length\n");
419      mbuf_Free(bp);
420      return;
421    }
422    if (iresult == PKT_ALIAS_OK
423	|| iresult == PKT_ALIAS_FOUND_HEADER_FRAGMENT) {
424      if (PacketCheck(bundle, tun.data, nb, &bundle->filter.in) < 0) {
425	mbuf_Free(bp);
426	return;
427      }
428
429      if (!(FilterCheck(pip, &bundle->filter.alive) & A_DENY))
430        bundle_StartIdleTimer(bundle);
431
432      ipcp_AddInOctets(&bundle->ncp.ipcp, nb);
433
434      nb = ntohs(((struct ip *) tun.data)->ip_len);
435      nb += sizeof tun - sizeof tun.data;
436      nw = write(bundle->dev.fd, &tun, nb);
437      if (nw != nb) {
438        if (nw == -1)
439	  log_Printf(LogERROR, "ip_Input: wrote %d, got %s\n", nb,
440                    strerror(errno));
441        else
442	  log_Printf(LogERROR, "ip_Input: wrote %d, got %d\n", nb, nw);
443      }
444
445      if (iresult == PKT_ALIAS_FOUND_HEADER_FRAGMENT) {
446	while ((fptr = PacketAliasGetFragment(tun.data)) != NULL) {
447	  PacketAliasFragmentIn(tun.data, fptr);
448	  nb = ntohs(((struct ip *) fptr)->ip_len);
449          frag = (struct tun_data *)
450	    ((char *)fptr - sizeof tun + sizeof tun.data);
451          nb += sizeof tun - sizeof tun.data;
452	  nw = write(bundle->dev.fd, frag, nb);
453	  if (nw != nb) {
454            if (nw == -1)
455	      log_Printf(LogERROR, "ip_Input: wrote %d, got %s\n", nb,
456                        strerror(errno));
457            else
458	      log_Printf(LogERROR, "ip_Input: wrote %d, got %d\n", nb, nw);
459          }
460	  free(frag);
461	}
462      }
463    } else if (iresult == PKT_ALIAS_UNRESOLVED_FRAGMENT) {
464      nb = ntohs(((struct ip *) tun.data)->ip_len);
465      nb += sizeof tun - sizeof tun.data;
466      frag = (struct tun_data *)malloc(nb);
467      if (frag == NULL)
468	log_Printf(LogALERT, "ip_Input: Cannot allocate memory for fragment\n");
469      else {
470        tun_fill_header(*frag, AF_INET);
471	memcpy(frag->data, tun.data, nb - sizeof tun + sizeof tun.data);
472	PacketAliasSaveFragment(frag->data);
473      }
474    }
475  } else
476#endif /* #ifndef NOALIAS */
477  {			/* no aliasing */
478    if (PacketCheck(bundle, tun.data, nb, &bundle->filter.in) < 0) {
479      mbuf_Free(bp);
480      return;
481    }
482
483    if (!(FilterCheck(pip, &bundle->filter.alive) & A_DENY))
484      bundle_StartIdleTimer(bundle);
485
486    ipcp_AddInOctets(&bundle->ncp.ipcp, nb);
487
488    nb += sizeof tun - sizeof tun.data;
489    nw = write(bundle->dev.fd, &tun, nb);
490    if (nw != nb) {
491      if (nw == -1)
492	log_Printf(LogERROR, "ip_Input: wrote %d, got %s\n", nb, strerror(errno));
493      else
494        log_Printf(LogERROR, "ip_Input: wrote %d, got %d\n", nb, nw);
495    }
496  }
497  mbuf_Free(bp);
498}
499
500void
501ip_Enqueue(struct ipcp *ipcp, int pri, char *ptr, int count)
502{
503  struct mbuf *bp;
504
505  if (pri < 0 || pri > sizeof ipcp->Queue / sizeof ipcp->Queue[0])
506    log_Printf(LogERROR, "Can't store in ip queue %d\n", pri);
507  else {
508    bp = mbuf_Alloc(count, MB_IPQ);
509    memcpy(MBUF_CTOP(bp), ptr, count);
510    mbuf_Enqueue(&ipcp->Queue[pri], bp);
511  }
512}
513
514void
515ip_DeleteQueue(struct ipcp *ipcp)
516{
517  struct mqueue *queue;
518
519  for (queue = ipcp->Queue; queue < ipcp->Queue + PRI_MAX; queue++)
520    while (queue->top)
521      mbuf_Free(mbuf_Dequeue(queue));
522}
523
524int
525ip_QueueLen(struct ipcp *ipcp)
526{
527  struct mqueue *queue;
528  int result = 0;
529
530  for (queue = ipcp->Queue; queue < ipcp->Queue + PRI_MAX; queue++)
531    result += queue->qlen;
532
533  return result;
534}
535
536int
537ip_FlushPacket(struct link *l, struct bundle *bundle)
538{
539  struct ipcp *ipcp = &bundle->ncp.ipcp;
540  struct mqueue *queue;
541  struct mbuf *bp;
542  int cnt;
543
544  if (ipcp->fsm.state != ST_OPENED)
545    return 0;
546
547  for (queue = &ipcp->Queue[PRI_FAST]; queue >= ipcp->Queue; queue--)
548    if (queue->top) {
549      bp = mbuf_Dequeue(queue);
550      if (bp) {
551        struct ip *pip = (struct ip *)MBUF_CTOP(bp);
552
553	cnt = mbuf_Length(bp);
554        if (!(FilterCheck(pip, &bundle->filter.alive) & A_DENY))
555          bundle_StartIdleTimer(bundle);
556	vj_SendFrame(l, bp, bundle);
557        ipcp_AddOutOctets(ipcp, cnt);
558	return 1;
559      }
560    }
561
562  return 0;
563}
564