ip.c revision 75894 
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 * $FreeBSD: head/usr.sbin/ppp/ip.c 75894 2001-04-24 02:13:34Z brian $
21 *
22 *	TODO:
23 *		o Return ICMP message for filterd packet
24 *		  and optionaly record it into log.
25 */
26#include <sys/param.h>
27#include <sys/socket.h>
28#include <netinet/in.h>
29#include <netinet/in_systm.h>
30#include <netinet/ip.h>
31#include <netinet/ip_icmp.h>
32#include <netinet/udp.h>
33#include <netinet/tcp.h>
34#include <arpa/inet.h>
35#include <sys/un.h>
36
37#include <errno.h>
38#include <stdio.h>
39#include <string.h>
40#include <termios.h>
41#include <unistd.h>
42
43#include "layer.h"
44#include "proto.h"
45#include "mbuf.h"
46#include "log.h"
47#include "defs.h"
48#include "timer.h"
49#include "fsm.h"
50#include "lqr.h"
51#include "hdlc.h"
52#include "throughput.h"
53#include "iplist.h"
54#include "slcompress.h"
55#include "ipcp.h"
56#include "filter.h"
57#include "descriptor.h"
58#include "lcp.h"
59#include "ccp.h"
60#include "link.h"
61#include "mp.h"
62#ifndef NORADIUS
63#include "radius.h"
64#endif
65#include "bundle.h"
66#include "tun.h"
67#include "ip.h"
68
69
70#define OPCODE_QUERY	0
71#define OPCODE_IQUERY	1
72#define OPCODE_STATUS	2
73
74struct dns_header {
75  u_short id;
76  unsigned qr : 1;
77  unsigned opcode : 4;
78  unsigned aa : 1;
79  unsigned tc : 1;
80  unsigned rd : 1;
81  unsigned ra : 1;
82  unsigned z : 3;
83  unsigned rcode : 4;
84  u_short qdcount;
85  u_short ancount;
86  u_short nscount;
87  u_short arcount;
88};
89
90static const char *
91dns_Qclass2Txt(u_short qclass)
92{
93  static char failure[6];
94  struct {
95    u_short id;
96    const char *txt;
97  } qtxt[] = {
98    /* rfc1035 */
99    { 1, "IN" }, { 2, "CS" }, { 3, "CH" }, { 4, "HS" }, { 255, "*" }
100  };
101  int f;
102
103  for (f = 0; f < sizeof qtxt / sizeof *qtxt; f++)
104    if (qtxt[f].id == qclass)
105      return qtxt[f].txt;
106
107  return HexStr(qclass, failure, sizeof failure);
108}
109
110static const char *
111dns_Qtype2Txt(u_short qtype)
112{
113  static char failure[6];
114  struct {
115    u_short id;
116    const char *txt;
117  } qtxt[] = {
118    /* rfc1035/rfc1700 */
119    { 1, "A" }, { 2, "NS" }, { 3, "MD" }, { 4, "MF" }, { 5, "CNAME" },
120    { 6, "SOA" }, { 7, "MB" }, { 8, "MG" }, { 9, "MR" }, { 10, "NULL" },
121    { 11, "WKS" }, { 12, "PTR" }, { 13, "HINFO" }, { 14, "MINFO" },
122    { 15, "MX" }, { 16, "TXT" }, { 17, "RP" }, { 18, "AFSDB" },
123    { 19, "X25" }, { 20, "ISDN" }, { 21, "RT" }, { 22, "NSAP" },
124    { 23, "NSAP-PTR" }, { 24, "SIG" }, { 25, "KEY" }, { 26, "PX" },
125    { 27, "GPOS" }, { 28, "AAAA" }, { 252, "AXFR" }, { 253, "MAILB" },
126    { 254, "MAILA" }, { 255, "*" }
127  };
128  int f;
129
130  for (f = 0; f < sizeof qtxt / sizeof *qtxt; f++)
131    if (qtxt[f].id == qtype)
132      return qtxt[f].txt;
133
134  return HexStr(qtype, failure, sizeof failure);
135}
136
137static __inline int
138PortMatch(int op, u_short pport, u_short rport)
139{
140  switch (op) {
141  case OP_EQ:
142    return pport == rport;
143  case OP_GT:
144    return pport > rport;
145  case OP_LT:
146    return pport < rport;
147  default:
148    return 0;
149  }
150}
151
152/*
153 *  Check a packet against a defined filter
154 *  Returns 0 to accept the packet, non-zero to drop the packet
155 *
156 *  If filtering is enabled, the initial fragment of a datagram must
157 *  contain the complete protocol header, and subsequent fragments
158 *  must not attempt to over-write it.
159 */
160static int
161FilterCheck(const struct ip *pip, const struct filter *filter, unsigned *psecs)
162{
163  int gotinfo;			/* true if IP payload decoded */
164  int cproto;			/* P_* protocol type if (gotinfo) */
165  int estab, syn, finrst;	/* TCP state flags if (gotinfo) */
166  u_short sport, dport;		/* src, dest port from packet if (gotinfo) */
167  int n;			/* filter rule to process */
168  int len;			/* bytes used in dbuff */
169  int didname;			/* true if filter header printed */
170  int match;			/* true if condition matched */
171  const struct filterent *fp = filter->rule;
172  char dbuff[100], dstip[16];
173
174  if (fp->f_action == A_NONE)
175    return 0;		/* No rule is given. Permit this packet */
176
177  /*
178   * Deny any packet fragment that tries to over-write the header.
179   * Since we no longer have the real header available, punt on the
180   * largest normal header - 20 bytes for TCP without options, rounded
181   * up to the next possible fragment boundary.  Since the smallest
182   * `legal' MTU is 576, and the smallest recommended MTU is 296, any
183   * fragmentation within this range is dubious at best
184   */
185  len = ntohs(pip->ip_off) & IP_OFFMASK;	/* fragment offset */
186  if (len > 0) {		/* Not first fragment within datagram */
187    if (len < (24 >> 3)) {	/* don't allow fragment to over-write header */
188      log_Printf(LogFILTER, " error: illegal header\n");
189      return 1;
190    }
191    /* permit fragments on in and out filter */
192    if (!filter->fragok) {
193      log_Printf(LogFILTER, " error: illegal fragmentation\n");
194      return 1;
195    } else
196      return 0;
197  }
198
199  cproto = gotinfo = estab = syn = finrst = didname = 0;
200  sport = dport = 0;
201  for (n = 0; n < MAXFILTERS; ) {
202    if (fp->f_action == A_NONE) {
203      n++;
204      fp++;
205      continue;
206    }
207
208    if (!didname) {
209      log_Printf(LogDEBUG, "%s filter:\n", filter->name);
210      didname = 1;
211    }
212
213    match = 0;
214    if (!((pip->ip_src.s_addr ^ fp->f_src.ipaddr.s_addr) &
215          fp->f_src.mask.s_addr) &&
216        !((pip->ip_dst.s_addr ^ fp->f_dst.ipaddr.s_addr) &
217          fp->f_dst.mask.s_addr)) {
218      if (fp->f_proto != P_NONE) {
219        if (!gotinfo) {
220          const char *ptop = (const char *) pip + (pip->ip_hl << 2);
221          const struct tcphdr *th;
222          const struct udphdr *uh;
223          const struct icmp *ih;
224          int datalen;	/* IP datagram length */
225
226          datalen = ntohs(pip->ip_len) - (pip->ip_hl << 2);
227          switch (pip->ip_p) {
228          case IPPROTO_ICMP:
229            cproto = P_ICMP;
230            if (datalen < 8) {	/* ICMP must be at least 8 octets */
231              log_Printf(LogFILTER, " error: ICMP must be at least 8 octets\n");
232              return 1;
233            }
234
235            ih = (const struct icmp *) ptop;
236            sport = ih->icmp_type;
237            estab = syn = finrst = -1;
238            if (log_IsKept(LogDEBUG))
239              snprintf(dbuff, sizeof dbuff, "sport = %d", sport);
240            break;
241          case IPPROTO_IGMP:
242            cproto = P_IGMP;
243            if (datalen < 8) {	/* IGMP uses 8-octet messages */
244              log_Printf(LogFILTER, " error: IGMP must be at least 8 octets\n");
245              return 1;
246            }
247            estab = syn = finrst = -1;
248            sport = ntohs(0);
249            break;
250#ifdef IPPROTO_GRE
251          case IPPROTO_GRE:
252            cproto = P_GRE;
253            if (datalen < 2) {    /* GRE uses 2-octet+ messages */
254              log_Printf(LogFILTER, " error: GRE must be at least 2 octets\n");
255              return 1;
256            }
257            estab = syn = finrst = -1;
258            sport = ntohs(0);
259            break;
260#endif
261#ifdef IPPROTO_OSPFIGP
262          case IPPROTO_OSPFIGP:
263            cproto = P_OSPF;
264            if (datalen < 8) {	/* IGMP uses 8-octet messages */
265              log_Printf(LogFILTER, " error: IGMP must be at least 8 octets\n");
266              return 1;
267            }
268            estab = syn = finrst = -1;
269            sport = ntohs(0);
270            break;
271#endif
272          case IPPROTO_ESP:
273            cproto = P_ESP;
274            estab = syn = finrst = -1;
275            sport = ntohs(0);
276            break;
277          case IPPROTO_AH:
278            cproto = P_AH;
279            estab = syn = finrst = -1;
280            sport = ntohs(0);
281            break;
282          case IPPROTO_IPIP:
283            cproto = P_IPIP;
284            sport = dport = 0;
285            estab = syn = finrst = -1;
286            break;
287          case IPPROTO_UDP:
288            cproto = P_UDP;
289            if (datalen < 8) {	/* UDP header is 8 octets */
290              log_Printf(LogFILTER, " error: UDP/IPIP"
291                         " must be at least 8 octets\n");
292              return 1;
293            }
294
295            uh = (const struct udphdr *) ptop;
296            sport = ntohs(uh->uh_sport);
297            dport = ntohs(uh->uh_dport);
298            estab = syn = finrst = -1;
299            if (log_IsKept(LogDEBUG))
300              snprintf(dbuff, sizeof dbuff, "sport = %d, dport = %d",
301                       sport, dport);
302            break;
303          case IPPROTO_TCP:
304            cproto = P_TCP;
305            th = (const struct tcphdr *) ptop;
306            /* TCP headers are variable length.  The following code
307             * ensures that the TCP header length isn't de-referenced if
308             * the datagram is too short
309             */
310            if (datalen < 20 || datalen < (th->th_off << 2)) {
311              log_Printf(LogFILTER, " error: TCP header incorrect\n");
312              return 1;
313            }
314            sport = ntohs(th->th_sport);
315            dport = ntohs(th->th_dport);
316            estab = (th->th_flags & TH_ACK);
317            syn = (th->th_flags & TH_SYN);
318            finrst = (th->th_flags & (TH_FIN|TH_RST));
319            if (log_IsKept(LogDEBUG)) {
320              if (!estab)
321                snprintf(dbuff, sizeof dbuff,
322                         "flags = %02x, sport = %d, dport = %d",
323                         th->th_flags, sport, dport);
324              else
325                *dbuff = '\0';
326            }
327            break;
328          default:
329            log_Printf(LogFILTER, " error: unknown protocol\n");
330            return 1;		/* We'll block unknown type of packet */
331          }
332
333          if (log_IsKept(LogDEBUG)) {
334            if (estab != -1) {
335              len = strlen(dbuff);
336              snprintf(dbuff + len, sizeof dbuff - len,
337                       ", estab = %d, syn = %d, finrst = %d",
338                       estab, syn, finrst);
339            }
340            log_Printf(LogDEBUG, " Filter: proto = %s, %s\n",
341                       filter_Proto2Nam(cproto), dbuff);
342          }
343          gotinfo = 1;
344        }
345        if (log_IsKept(LogDEBUG)) {
346          if (fp->f_srcop != OP_NONE) {
347            snprintf(dbuff, sizeof dbuff, ", src %s %d",
348                     filter_Op2Nam(fp->f_srcop), fp->f_srcport);
349            len = strlen(dbuff);
350          } else
351            len = 0;
352          if (fp->f_dstop != OP_NONE) {
353            snprintf(dbuff + len, sizeof dbuff - len,
354                     ", dst %s %d", filter_Op2Nam(fp->f_dstop),
355                     fp->f_dstport);
356          } else if (!len)
357            *dbuff = '\0';
358
359          log_Printf(LogDEBUG, "  rule = %d: Address match, "
360                     "check against proto %s%s, action = %s\n",
361                     n, filter_Proto2Nam(fp->f_proto),
362                     dbuff, filter_Action2Nam(fp->f_action));
363        }
364
365        if (cproto == fp->f_proto) {
366          if ((fp->f_srcop == OP_NONE ||
367               PortMatch(fp->f_srcop, sport, fp->f_srcport)) &&
368              (fp->f_dstop == OP_NONE ||
369               PortMatch(fp->f_dstop, dport, fp->f_dstport)) &&
370              (fp->f_estab == 0 || estab) &&
371              (fp->f_syn == 0 || syn) &&
372              (fp->f_finrst == 0 || finrst)) {
373            match = 1;
374          }
375        }
376      } else {
377        /* Address is matched and no protocol specified. Make a decision. */
378        log_Printf(LogDEBUG, "  rule = %d: Address match, action = %s\n", n,
379                   filter_Action2Nam(fp->f_action));
380        match = 1;
381      }
382    } else
383      log_Printf(LogDEBUG, "  rule = %d: Address mismatch\n", n);
384
385    if (match != fp->f_invert) {
386      /* Take specified action */
387      if (fp->f_action < A_NONE)
388        fp = &filter->rule[n = fp->f_action];
389      else {
390        if (fp->f_action == A_PERMIT) {
391          if (psecs != NULL)
392            *psecs = fp->timeout;
393          if (strcmp(filter->name, "DIAL") == 0) {
394            /* If dial filter then even print out accept packets */
395            if (log_IsKept(LogFILTER)) {
396              snprintf(dstip, sizeof dstip, "%s", inet_ntoa(pip->ip_dst));
397              log_Printf(LogFILTER, "%sbound rule = %d accept %s "
398                         "src = %s/%d dst = %s/%d\n",
399                         filter->name, n, filter_Proto2Nam(cproto),
400                         inet_ntoa(pip->ip_src), sport, dstip, dport);
401            }
402          }
403          return 0;
404        } else {
405          if (log_IsKept(LogFILTER)) {
406            snprintf(dstip, sizeof dstip, "%s", inet_ntoa(pip->ip_dst));
407            log_Printf(LogFILTER,
408                       "%sbound rule = %d deny %s src = %s/%d dst = %s/%d\n",
409                       filter->name, n, filter_Proto2Nam(cproto),
410                       inet_ntoa(pip->ip_src), sport, dstip, dport);
411          }
412          return 1;
413        }		/* Explict math.  Deny this packet */
414      }
415    } else {
416      n++;
417      fp++;
418    }
419  }
420
421  if (log_IsKept(LogFILTER)) {
422    snprintf(dstip, sizeof dstip, "%s", inet_ntoa(pip->ip_dst));
423    log_Printf(LogFILTER,
424               "%sbound rule = implicit deny %s src = %s/%d dst = %s/%d\n",
425               filter->name, filter_Proto2Nam(cproto),
426               inet_ntoa(pip->ip_src), sport, dstip, dport);
427  }
428
429  return 1;		/* No rule is mached. Deny this packet */
430}
431
432#ifdef notdef
433static void
434IcmpError(struct ip *pip, int code)
435{
436  struct mbuf *bp;
437
438  if (pip->ip_p != IPPROTO_ICMP) {
439    bp = m_get(m_len, MB_IPIN);
440    memcpy(MBUF_CTOP(bp), ptr, m_len);
441    vj_SendFrame(bp);
442    ipcp_AddOutOctets(m_len);
443  }
444}
445#endif
446
447static void
448ip_LogDNS(const struct udphdr *uh, const char *direction)
449{
450  struct dns_header header;
451  const u_short *pktptr;
452  const u_char *ptr;
453  u_short *hptr;
454  int len;
455
456  ptr = (const char *)uh + sizeof *uh;
457  len = ntohs(uh->uh_ulen) - sizeof *uh;
458  if (len < sizeof header + 5)		/* rfc1024 */
459    return;
460
461  pktptr = (const u_short *)ptr;
462  hptr = (u_short *)&header;
463  ptr += sizeof header;
464  len -= sizeof header;
465
466  while (pktptr < (const u_short *)ptr) {
467    *hptr++ = ntohs(*pktptr);		/* Careful of macro side-effects ! */
468    pktptr++;
469  }
470
471  if (header.opcode == OPCODE_QUERY && header.qr == 0) {
472    /* rfc1035 */
473    char namewithdot[MAXHOSTNAMELEN + 1], *n;
474    const char *qtype, *qclass;
475    const u_char *end;
476
477    n = namewithdot;
478    end = ptr + len - 4;
479    if (end - ptr >= sizeof namewithdot)
480      end = ptr + sizeof namewithdot - 1;
481    while (ptr < end) {
482      len = *ptr++;
483      if (len > end - ptr)
484        len = end - ptr;
485      if (n != namewithdot)
486        *n++ = '.';
487      memcpy(n, ptr, len);
488      ptr += len;
489      n += len;
490    }
491    *n = '\0';
492    qtype = dns_Qtype2Txt(ntohs(*(const u_short *)end));
493    qclass = dns_Qclass2Txt(ntohs(*(const u_short *)(end + 2)));
494
495    log_Printf(LogDNS, "%sbound query %s %s %s\n",
496               direction, qclass, qtype, namewithdot);
497  }
498}
499
500/*
501 *  For debugging aid.
502 */
503int
504PacketCheck(struct bundle *bundle, unsigned char *cp, int nb,
505            struct filter *filter, const char *prefix, unsigned *psecs)
506{
507  static const char *const TcpFlags[] = {
508    "FIN", "SYN", "RST", "PSH", "ACK", "URG"
509  };
510  struct ip *pip;
511  struct tcphdr *th;
512  struct udphdr *uh;
513  struct icmp *icmph;
514  unsigned char *ptop;
515  int mask, len, n, pri, logit, loglen, result;
516  char logbuf[200];
517
518  logit = (log_IsKept(LogTCPIP) || log_IsKept(LogDNS)) &&
519          (!filter || filter->logok);
520  loglen = 0;
521  pri = 0;
522
523  pip = (struct ip *)cp;
524  uh = NULL;
525
526  if (logit && loglen < sizeof logbuf) {
527    if (prefix)
528      snprintf(logbuf + loglen, sizeof logbuf - loglen, "%s", prefix);
529    else if (filter)
530      snprintf(logbuf + loglen, sizeof logbuf - loglen, "%s ", filter->name);
531    else
532      snprintf(logbuf + loglen, sizeof logbuf - loglen, "  ");
533    loglen += strlen(logbuf + loglen);
534  }
535  ptop = (cp + (pip->ip_hl << 2));
536
537  switch (pip->ip_p) {
538  case IPPROTO_ICMP:
539    if (logit && loglen < sizeof logbuf) {
540      len = ntohs(pip->ip_len) - (pip->ip_hl << 2) - sizeof *icmph;
541      icmph = (struct icmp *) ptop;
542      snprintf(logbuf + loglen, sizeof logbuf - loglen,
543               "ICMP: %s:%d ---> ", inet_ntoa(pip->ip_src), icmph->icmp_type);
544      loglen += strlen(logbuf + loglen);
545      snprintf(logbuf + loglen, sizeof logbuf - loglen,
546               "%s:%d (%d/%d)", inet_ntoa(pip->ip_dst), icmph->icmp_type,
547               len, nb);
548      loglen += strlen(logbuf + loglen);
549    }
550    break;
551
552  case IPPROTO_UDP:
553    uh = (struct udphdr *) ptop;
554    if (pip->ip_tos == IPTOS_LOWDELAY && bundle->ncp.ipcp.cfg.urgent.tos)
555      pri++;
556
557    if ((ntohs(pip->ip_off) & IP_OFFMASK) == 0 &&
558        ipcp_IsUrgentUdpPort(&bundle->ncp.ipcp, ntohs(uh->uh_sport),
559                          ntohs(uh->uh_dport)))
560      pri++;
561
562    if (logit && loglen < sizeof logbuf) {
563      len = ntohs(pip->ip_len) - (pip->ip_hl << 2) - sizeof *uh;
564      snprintf(logbuf + loglen, sizeof logbuf - loglen,
565               "UDP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport));
566      loglen += strlen(logbuf + loglen);
567      snprintf(logbuf + loglen, sizeof logbuf - loglen,
568               "%s:%d (%d/%d)", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport),
569               len, nb);
570      loglen += strlen(logbuf + loglen);
571    }
572
573    if (Enabled(bundle, OPT_FILTERDECAP) &&
574        ptop[sizeof *uh] == HDLC_ADDR && ptop[sizeof *uh + 1] == HDLC_UI) {
575      u_short proto;
576      const char *type;
577
578      memcpy(&proto, ptop + sizeof *uh + 2, sizeof proto);
579      type = NULL;
580
581      switch (ntohs(proto)) {
582        case PROTO_IP:
583          snprintf(logbuf + loglen, sizeof logbuf - loglen, " contains ");
584          result = PacketCheck(bundle, ptop + sizeof *uh + 4,
585                               nb - (ptop - cp) - sizeof *uh - 4, filter,
586                               logbuf, psecs);
587          if (result != -2)
588              return result;
589          type = "IP";
590          break;
591
592        case PROTO_VJUNCOMP: type = "compressed VJ";   break;
593        case PROTO_VJCOMP:   type = "uncompressed VJ"; break;
594        case PROTO_MP:       type = "Multi-link"; break;
595        case PROTO_ICOMPD:   type = "Individual link CCP"; break;
596        case PROTO_COMPD:    type = "CCP"; break;
597        case PROTO_IPCP:     type = "IPCP"; break;
598        case PROTO_LCP:      type = "LCP"; break;
599        case PROTO_PAP:      type = "PAP"; break;
600        case PROTO_CBCP:     type = "CBCP"; break;
601        case PROTO_LQR:      type = "LQR"; break;
602        case PROTO_CHAP:     type = "CHAP"; break;
603      }
604      if (type) {
605        snprintf(logbuf + loglen, sizeof logbuf - loglen,
606                 " - %s data", type);
607        loglen += strlen(logbuf + loglen);
608      }
609    }
610
611    break;
612
613#ifdef IPPROTO_GRE
614  case IPPROTO_GRE:
615    if (logit && loglen < sizeof logbuf) {
616      len = ntohs(pip->ip_len) - (pip->ip_hl << 2);
617      snprintf(logbuf + loglen, sizeof logbuf - loglen,
618          "GRE: %s ---> ", inet_ntoa(pip->ip_src));
619      loglen += strlen(logbuf + loglen);
620      snprintf(logbuf + loglen, sizeof logbuf - loglen,
621              "%s (%d/%d)", inet_ntoa(pip->ip_dst), len, nb);
622      loglen += strlen(logbuf + loglen);
623    }
624    break;
625#endif
626
627#ifdef IPPROTO_OSPFIGP
628  case IPPROTO_OSPFIGP:
629    if (logit && loglen < sizeof logbuf) {
630      len = ntohs(pip->ip_len) - (pip->ip_hl << 2);
631      snprintf(logbuf + loglen, sizeof logbuf - loglen,
632               "OSPF: %s ---> ", inet_ntoa(pip->ip_src));
633      loglen += strlen(logbuf + loglen);
634      snprintf(logbuf + loglen, sizeof logbuf - loglen,
635               "%s (%d/%d)", inet_ntoa(pip->ip_dst), len, nb);
636      loglen += strlen(logbuf + loglen);
637    }
638    break;
639#endif
640
641  case IPPROTO_IPIP:
642    if (logit && loglen < sizeof logbuf) {
643      snprintf(logbuf + loglen, sizeof logbuf - loglen,
644               "IPIP: %s ---> ", inet_ntoa(pip->ip_src));
645      loglen += strlen(logbuf + loglen);
646      snprintf(logbuf + loglen, sizeof logbuf - loglen,
647               "%s", inet_ntoa(pip->ip_dst));
648      loglen += strlen(logbuf + loglen);
649
650      if (((struct ip *)ptop)->ip_v == 4) {
651        snprintf(logbuf + loglen, sizeof logbuf - loglen, " contains ");
652        result = PacketCheck(bundle, ptop, nb - (ptop - cp), filter,
653                             logbuf, psecs);
654        if (result != -2)
655          return result;
656      }
657    }
658    break;
659
660  case IPPROTO_ESP:
661    if (logit && loglen < sizeof logbuf) {
662      snprintf(logbuf + loglen, sizeof logbuf - loglen,
663               "ESP: %s ---> ", inet_ntoa(pip->ip_src));
664      loglen += strlen(logbuf + loglen);
665      snprintf(logbuf + loglen, sizeof logbuf - loglen, "%s, spi %p",
666               inet_ntoa(pip->ip_dst), ptop);
667      loglen += strlen(logbuf + loglen);
668    }
669    break;
670
671  case IPPROTO_AH:
672    if (logit && loglen < sizeof logbuf) {
673      snprintf(logbuf + loglen, sizeof logbuf - loglen,
674               "AH: %s ---> ", inet_ntoa(pip->ip_src));
675      loglen += strlen(logbuf + loglen);
676      snprintf(logbuf + loglen, sizeof logbuf - loglen, "%s, spi %p",
677               inet_ntoa(pip->ip_dst), ptop + sizeof(u_int32_t));
678      loglen += strlen(logbuf + loglen);
679    }
680    break;
681
682  case IPPROTO_IGMP:
683    if (logit && loglen < sizeof logbuf) {
684      uh = (struct udphdr *) ptop;
685      snprintf(logbuf + loglen, sizeof logbuf - loglen,
686               "IGMP: %s:%d ---> ", inet_ntoa(pip->ip_src),
687               ntohs(uh->uh_sport));
688      loglen += strlen(logbuf + loglen);
689      snprintf(logbuf + loglen, sizeof logbuf - loglen,
690               "%s:%d", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport));
691      loglen += strlen(logbuf + loglen);
692    }
693    break;
694
695  case IPPROTO_TCP:
696    th = (struct tcphdr *) ptop;
697    if (pip->ip_tos == IPTOS_LOWDELAY && bundle->ncp.ipcp.cfg.urgent.tos)
698      pri++;
699
700    if ((ntohs(pip->ip_off) & IP_OFFMASK) == 0 &&
701        ipcp_IsUrgentTcpPort(&bundle->ncp.ipcp, ntohs(th->th_sport),
702                          ntohs(th->th_dport)))
703      pri++;
704
705    if (logit && loglen < sizeof logbuf) {
706      len = ntohs(pip->ip_len) - (pip->ip_hl << 2) - (th->th_off << 2);
707      snprintf(logbuf + loglen, sizeof logbuf - loglen,
708           "TCP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(th->th_sport));
709      loglen += strlen(logbuf + loglen);
710      snprintf(logbuf + loglen, sizeof logbuf - loglen,
711               "%s:%d", inet_ntoa(pip->ip_dst), ntohs(th->th_dport));
712      loglen += strlen(logbuf + loglen);
713      n = 0;
714      for (mask = TH_FIN; mask != 0x40; mask <<= 1) {
715        if (th->th_flags & mask) {
716          snprintf(logbuf + loglen, sizeof logbuf - loglen, " %s", TcpFlags[n]);
717          loglen += strlen(logbuf + loglen);
718        }
719        n++;
720      }
721      snprintf(logbuf + loglen, sizeof logbuf - loglen,
722               "  seq:%lx  ack:%lx (%d/%d)",
723               (u_long)ntohl(th->th_seq), (u_long)ntohl(th->th_ack), len, nb);
724      loglen += strlen(logbuf + loglen);
725      if ((th->th_flags & TH_SYN) && nb > 40) {
726        u_short *sp;
727
728        ptop += 20;
729        sp = (u_short *) ptop;
730        if (ntohs(sp[0]) == 0x0204) {
731          snprintf(logbuf + loglen, sizeof logbuf - loglen,
732                   " MSS = %d", ntohs(sp[1]));
733          loglen += strlen(logbuf + loglen);
734        }
735      }
736    }
737    break;
738
739  default:
740    if (prefix)
741      return -2;
742  }
743
744  if (filter && FilterCheck(pip, filter, psecs)) {
745    if (logit)
746      log_Printf(LogTCPIP, "%s - BLOCKED\n", logbuf);
747#ifdef notdef
748    if (direction == 0)
749      IcmpError(pip, pri);
750#endif
751    result = -1;
752  } else {
753    /* Check Keep Alive filter */
754    if (logit && log_IsKept(LogTCPIP)) {
755      unsigned alivesecs;
756
757      alivesecs = 0;
758      if (filter && FilterCheck(pip, &bundle->filter.alive, &alivesecs))
759        log_Printf(LogTCPIP, "%s - NO KEEPALIVE\n", logbuf);
760      else if (psecs != NULL) {
761        if(*psecs == 0)
762          *psecs = alivesecs;
763        if (*psecs) {
764          if (*psecs != alivesecs)
765            log_Printf(LogTCPIP, "%s - (timeout = %d / ALIVE = %d secs)\n",
766                       logbuf, *psecs, alivesecs);
767          else
768            log_Printf(LogTCPIP, "%s - (timeout = %d secs)\n", logbuf, *psecs);
769        } else
770          log_Printf(LogTCPIP, "%s\n", logbuf);
771      }
772    }
773    result = pri;
774  }
775
776  if (filter && uh && ntohs(uh->uh_dport) == 53 && log_IsKept(LogDNS))
777    ip_LogDNS(uh, filter->name);
778
779  return result;
780}
781
782struct mbuf *
783ip_Input(struct bundle *bundle, struct link *l, struct mbuf *bp)
784{
785  int nb, nw;
786  struct tun_data tun;
787  struct ip *pip;
788  char *data;
789  unsigned secs, alivesecs;
790
791  if (bundle->ncp.ipcp.fsm.state != ST_OPENED) {
792    log_Printf(LogWARN, "ip_Input: IPCP not open - packet dropped\n");
793    m_freem(bp);
794    return NULL;
795  }
796
797  m_settype(bp, MB_IPIN);
798  nb = m_length(bp);
799  if (nb > sizeof tun.data) {
800    log_Printf(LogWARN, "ip_Input: %s: Packet too large (got %d, max %d)\n",
801               l->name, nb, (int)(sizeof tun.data));
802    m_freem(bp);
803    return NULL;
804  }
805  mbuf_Read(bp, tun.data, nb);
806
807  secs = 0;
808  if (PacketCheck(bundle, tun.data, nb, &bundle->filter.in, NULL, &secs) < 0)
809    return NULL;
810
811  pip = (struct ip *)tun.data;
812  alivesecs = 0;
813  if (!FilterCheck(pip, &bundle->filter.alive, &alivesecs)) {
814    if (secs == 0)
815      secs = alivesecs;
816    bundle_StartIdleTimer(bundle, secs);
817  }
818
819  ipcp_AddInOctets(&bundle->ncp.ipcp, nb);
820
821  if (bundle->dev.header) {
822    tun.header.family = htonl(AF_INET);
823    nb += sizeof tun - sizeof tun.data;
824    data = (char *)&tun;
825  } else
826    data = tun.data;
827
828  nw = write(bundle->dev.fd, data, nb);
829  if (nw != nb) {
830    if (nw == -1)
831      log_Printf(LogERROR, "ip_Input: %s: wrote %d, got %s\n",
832                 l->name, nb, strerror(errno));
833    else
834      log_Printf(LogERROR, "ip_Input: %s: wrote %d, got %d\n", l->name, nb, nw);
835  }
836
837  return NULL;
838}
839
840void
841ip_Enqueue(struct ipcp *ipcp, int pri, char *ptr, int count)
842{
843  struct mbuf *bp;
844
845  if (pri < 0 || pri >= IPCP_QUEUES(ipcp))
846    log_Printf(LogERROR, "Can't store in ip queue %d\n", pri);
847  else {
848    /*
849     * We allocate an extra 6 bytes, four at the front and two at the end.
850     * This is an optimisation so that we need to do less work in
851     * m_prepend() in acf_LayerPush() and proto_LayerPush() and
852     * appending in hdlc_LayerPush().
853     */
854    bp = m_get(count + 6, MB_IPOUT);
855    bp->m_offset += 4;
856    bp->m_len -= 6;
857    memcpy(MBUF_CTOP(bp), ptr, count);
858    m_enqueue(ipcp->Queue + pri, bp);
859  }
860}
861
862void
863ip_DeleteQueue(struct ipcp *ipcp)
864{
865  struct mqueue *queue;
866
867  for (queue = ipcp->Queue; queue < ipcp->Queue + IPCP_QUEUES(ipcp); queue++)
868    while (queue->top)
869      m_freem(m_dequeue(queue));
870}
871
872size_t
873ip_QueueLen(struct ipcp *ipcp)
874{
875  struct mqueue *queue;
876  size_t result;
877
878  result = 0;
879  for (queue = ipcp->Queue; queue < ipcp->Queue + IPCP_QUEUES(ipcp); queue++)
880    result += queue->len;
881
882  return result;
883}
884
885int
886ip_PushPacket(struct link *l, struct bundle *bundle)
887{
888  struct ipcp *ipcp = &bundle->ncp.ipcp;
889  struct mqueue *queue;
890  struct mbuf *bp;
891  struct ip *pip;
892  int m_len;
893  u_int32_t secs = 0;
894  unsigned alivesecs = 0;
895
896  if (ipcp->fsm.state != ST_OPENED)
897    return 0;
898
899  queue = ipcp->Queue + IPCP_QUEUES(ipcp) - 1;
900  do {
901    if (queue->top) {
902      bp = m_dequeue(queue);
903      bp = mbuf_Read(bp, &secs, sizeof secs);
904      bp = m_pullup(bp);
905      m_len = m_length(bp);
906      pip = (struct ip *)MBUF_CTOP(bp);
907      if (!FilterCheck(pip, &bundle->filter.alive, &alivesecs)) {
908        if (secs == 0)
909          secs = alivesecs;
910        bundle_StartIdleTimer(bundle, secs);
911      }
912      link_PushPacket(l, bp, bundle, 0, PROTO_IP);
913      ipcp_AddOutOctets(ipcp, m_len);
914      return 1;
915    }
916  } while (queue-- != ipcp->Queue);
917
918  return 0;
919}
920