1 /* $OpenBSD: print-ip.c,v 1.53 2020/01/24 22:46:36 procter Exp $ */
2
3 /*
4 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that: (1) source code distributions
9 * retain the above copyright notice and this paragraph in its entirety, (2)
10 * distributions including binary code include the above copyright notice and
11 * this paragraph in its entirety in the documentation or other materials
12 * provided with the distribution, and (3) all advertising materials mentioning
13 * features or use of this software display the following acknowledgement:
14 * ``This product includes software developed by the University of California,
15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16 * the University nor the names of its contributors may be used to endorse
17 * or promote products derived from this software without specific prior
18 * written permission.
19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22 */
23
24 #include <sys/time.h>
25 #include <sys/socket.h>
26
27 #include <netinet/in.h>
28 #include <netinet/ip.h>
29 #include <netinet/ip_var.h>
30 #include <netinet/udp.h>
31 #include <netinet/udp_var.h>
32 #include <netinet/tcp.h>
33
34 #include <inttypes.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <unistd.h>
39
40 #include "addrtoname.h"
41 #include "interface.h"
42 #include "extract.h" /* must come after interface.h */
43
44 /* Compatibility */
45 #ifndef IPPROTO_ND
46 #define IPPROTO_ND 77
47 #endif
48
49 #ifndef IN_CLASSD
50 #define IN_CLASSD(i) (((int32_t)(i) & 0xf0000000) == 0xe0000000)
51 #endif
52
53 /* Definitions required for ECN
54 for use if the OS running tcpdump does not have ECN */
55 #ifndef IPTOS_ECT
56 #define IPTOS_ECT 0x02 /* ECN Capable Transport in IP header*/
57 #endif
58 #ifndef IPTOS_CE
59 #define IPTOS_CE 0x01 /* ECN Cong. Experienced in IP header*/
60 #endif
61
62 /* (following from ipmulti/mrouted/prune.h) */
63
64 /*
65 * The packet format for a traceroute request.
66 */
67 struct tr_query {
68 u_int tr_src; /* traceroute source */
69 u_int tr_dst; /* traceroute destination */
70 u_int tr_raddr; /* traceroute response address */
71 #if BYTE_ORDER == BIG_ENDIAN
72 struct {
73 u_int ttl : 8; /* traceroute response ttl */
74 u_int qid : 24; /* traceroute query id */
75 } q;
76 #else
77 struct {
78 u_int qid : 24; /* traceroute query id */
79 u_int ttl : 8; /* traceroute response ttl */
80 } q;
81 #endif
82 };
83
84 #define tr_rttl q.ttl
85 #define tr_qid q.qid
86
87 /*
88 * Traceroute response format. A traceroute response has a tr_query at the
89 * beginning, followed by one tr_resp for each hop taken.
90 */
91 struct tr_resp {
92 u_int tr_qarr; /* query arrival time */
93 u_int tr_inaddr; /* incoming interface address */
94 u_int tr_outaddr; /* outgoing interface address */
95 u_int tr_rmtaddr; /* parent address in source tree */
96 u_int tr_vifin; /* input packet count on interface */
97 u_int tr_vifout; /* output packet count on interface */
98 u_int tr_pktcnt; /* total incoming packets for src-grp */
99 u_char tr_rproto; /* routing proto deployed on router */
100 u_char tr_fttl; /* ttl required to forward on outvif */
101 u_char tr_smask; /* subnet mask for src addr */
102 u_char tr_rflags; /* forwarding error codes */
103 };
104
105 /* defs within mtrace */
106 #define TR_QUERY 1
107 #define TR_RESP 2
108
109 /* fields for tr_rflags (forwarding error codes) */
110 #define TR_NO_ERR 0
111 #define TR_WRONG_IF 1
112 #define TR_PRUNED 2
113 #define TR_OPRUNED 3
114 #define TR_SCOPED 4
115 #define TR_NO_RTE 5
116 #define TR_NO_FWD 7
117 #define TR_NO_SPACE 0x81
118 #define TR_OLD_ROUTER 0x82
119
120 /* fields for tr_rproto (routing protocol) */
121 #define TR_PROTO_DVMRP 1
122 #define TR_PROTO_MOSPF 2
123 #define TR_PROTO_PIM 3
124 #define TR_PROTO_CBT 4
125
print_mtrace(const u_char * bp,u_int len)126 static void print_mtrace(const u_char *bp, u_int len)
127 {
128 struct tr_query *tr = (struct tr_query *)(bp + 8);
129
130 printf("mtrace %d: %s to %s reply-to %s", tr->tr_qid,
131 ipaddr_string(&tr->tr_src), ipaddr_string(&tr->tr_dst),
132 ipaddr_string(&tr->tr_raddr));
133 if (IN_CLASSD(ntohl(tr->tr_raddr)))
134 printf(" with-ttl %d", tr->tr_rttl);
135 }
136
print_mresp(const u_char * bp,u_int len)137 static void print_mresp(const u_char *bp, u_int len)
138 {
139 struct tr_query *tr = (struct tr_query *)(bp + 8);
140
141 printf("mresp %d: %s to %s reply-to %s", tr->tr_qid,
142 ipaddr_string(&tr->tr_src), ipaddr_string(&tr->tr_dst),
143 ipaddr_string(&tr->tr_raddr));
144 if (IN_CLASSD(ntohl(tr->tr_raddr)))
145 printf(" with-ttl %d", tr->tr_rttl);
146 }
147
148 static void
igmp_print(const u_char * bp,u_int len,const u_char * bp2)149 igmp_print(const u_char *bp, u_int len, const u_char *bp2)
150 {
151 const struct ip *ip;
152
153 ip = (const struct ip *)bp2;
154 printf("%s > %s: ",
155 ipaddr_string(&ip->ip_src),
156 ipaddr_string(&ip->ip_dst));
157
158 TCHECK2(bp[0], 8);
159 switch (bp[0]) {
160 case 0x11:
161 printf("igmp query");
162 if (*(int *)&bp[4])
163 printf(" [gaddr %s]", ipaddr_string(&bp[4]));
164 if (len != 8)
165 printf(" [len %d]", len);
166 break;
167 case 0x12:
168 printf("igmp report %s", ipaddr_string(&bp[4]));
169 if (len != 8)
170 printf(" [len %d]", len);
171 break;
172 case 0x16:
173 printf("igmp nreport %s", ipaddr_string(&bp[4]));
174 break;
175 case 0x17:
176 printf("igmp leave %s", ipaddr_string(&bp[4]));
177 break;
178 case 0x13:
179 printf("igmp dvmrp");
180 if (len < 8)
181 printf(" [len %d]", len);
182 else
183 dvmrp_print(bp, len);
184 break;
185 case 0x14:
186 printf("igmp pim");
187 pim_print(bp, len);
188 break;
189 case 0x1e:
190 print_mresp(bp, len);
191 break;
192 case 0x1f:
193 print_mtrace(bp, len);
194 break;
195 default:
196 printf("igmp-%d", bp[0] & 0xf);
197 break;
198 }
199 if ((bp[0] >> 4) != 1)
200 printf(" [v%d]", bp[0] >> 4);
201
202 TCHECK2(bp[0], len);
203 if (vflag) {
204 /* Check the IGMP checksum */
205 u_int32_t sum = 0;
206 int count;
207 const u_short *sp = (u_short *)bp;
208
209 for (count = len / 2; --count >= 0; )
210 sum += *sp++;
211 if (len & 1)
212 sum += ntohs(*(u_char *) sp << 8);
213 while (sum >> 16)
214 sum = (sum & 0xffff) + (sum >> 16);
215 sum = 0xffff & ~sum;
216 if (sum != 0)
217 printf(" bad igmp cksum %x!", EXTRACT_16BITS(&bp[2]));
218 }
219 return;
220 trunc:
221 printf("[|igmp]");
222 }
223
224 /*
225 * print the recorded route in an IP RR, LSRR or SSRR option.
226 */
227 static void
ip_printroute(const char * type,const u_char * cp,u_int length)228 ip_printroute(const char *type, const u_char *cp, u_int length)
229 {
230 u_int ptr = cp[2] - 1;
231 u_int len;
232
233 printf(" %s{", type);
234 if ((length + 1) & 3)
235 printf(" [bad length %d]", length);
236 if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
237 printf(" [bad ptr %d]", cp[2]);
238
239 type = "";
240 for (len = 3; len < length; len += 4) {
241 if (ptr == len)
242 type = "#";
243 printf("%s%s", type, ipaddr_string(&cp[len]));
244 type = " ";
245 }
246 printf("%s}", ptr == len? "#" : "");
247 }
248
249 /*
250 * print IP options.
251 */
252 static void
ip_optprint(const u_char * cp,u_int length)253 ip_optprint(const u_char *cp, u_int length)
254 {
255 u_int len;
256 int tt;
257
258 for (; length > 0; cp += len, length -= len) {
259 TCHECK(cp[1]);
260 tt = *cp;
261 len = (tt == IPOPT_NOP || tt == IPOPT_EOL) ? 1 : cp[1];
262 if (len <= 0) {
263 printf("[|ip op len %d]", len);
264 return;
265 }
266 if (&cp[1] >= snapend || cp + len > snapend) {
267 printf("[|ip]");
268 return;
269 }
270 switch (tt) {
271
272 case IPOPT_EOL:
273 printf(" EOL");
274 if (length > 1)
275 printf("-%d", length - 1);
276 return;
277
278 case IPOPT_NOP:
279 printf(" NOP");
280 break;
281
282 case IPOPT_TS:
283 printf(" TS{%d}", len);
284 break;
285
286 case IPOPT_SECURITY:
287 printf(" SECURITY{%d}", len);
288 break;
289
290 case IPOPT_RR:
291 printf(" RR{%d}=", len);
292 ip_printroute("RR", cp, len);
293 break;
294
295 case IPOPT_SSRR:
296 ip_printroute("SSRR", cp, len);
297 break;
298
299 case IPOPT_LSRR:
300 ip_printroute("LSRR", cp, len);
301 break;
302
303 default:
304 printf(" IPOPT-%d{%d}", cp[0], len);
305 break;
306 }
307 }
308 return;
309
310 trunc:
311 printf("[|ip]");
312 }
313
314 /*
315 * print an IP datagram.
316 */
317 void
ip_print(const u_char * bp,u_int length)318 ip_print(const u_char *bp, u_int length)
319 {
320 const struct ip *ip;
321 u_int hlen, len, off;
322 const u_char *cp;
323 const u_char *pktp = packetp;
324 const u_char *send = snapend;
325
326 TCHECK2(bp[0], 1);
327 ip = (const struct ip *)bp;
328
329 /*
330 * If the IP header is not aligned, copy into abuf.
331 * This will never happen with BPF. It does happen with raw packet
332 * dumps from -r.
333 */
334 if ((intptr_t)ip & (sizeof(u_int32_t)-1)) {
335 static u_char *abuf = NULL;
336 static int didwarn = 0;
337 int clen = snapend - bp;
338
339 if (clen > snaplen)
340 clen = snaplen;
341 if (abuf == NULL) {
342 abuf = malloc(snaplen);
343 if (abuf == NULL)
344 error("ip_print: malloc");
345 }
346 memmove((char *)abuf, (char *)ip, min(length, clen));
347 snapend = abuf + clen;
348 packetp = abuf;
349 ip = (struct ip *)abuf;
350 /* We really want libpcap to give us aligned packets */
351 if (!didwarn) {
352 warning("compensating for unaligned libpcap packets");
353 ++didwarn;
354 }
355 }
356
357 TCHECK(*ip);
358 if (ip->ip_v != IPVERSION) {
359 printf("bad-ip-version %u", ip->ip_v);
360 goto out;
361 }
362
363 len = ntohs(ip->ip_len);
364 if (length < len) {
365 printf("truncated-ip - %d bytes missing!",
366 len - length);
367 len = length;
368 }
369
370 hlen = ip->ip_hl * 4;
371 if (hlen < sizeof(struct ip) || hlen > len) {
372 printf("bad-hlen %d", hlen);
373 goto out;
374 }
375
376 len -= hlen;
377
378 /*
379 * If this is fragment zero, hand it to the next higher
380 * level protocol.
381 */
382 off = ntohs(ip->ip_off);
383 if ((off & 0x1fff) == 0) {
384 cp = (const u_char *)ip + hlen;
385 if (cp > snapend)
386 goto trunc;
387 switch (ip->ip_p) {
388
389 case IPPROTO_TCP:
390 tcp_print(cp, len, (const u_char *)ip);
391 break;
392
393 case IPPROTO_UDP:
394 udp_print(cp, len, (const u_char *)ip);
395 break;
396
397 case IPPROTO_ICMP:
398 icmp_print(cp, len, (const u_char *)ip);
399 break;
400
401 #ifndef IPPROTO_IGRP
402 #define IPPROTO_IGRP 9
403 #endif
404 case IPPROTO_IGRP:
405 igrp_print(cp, len, (const u_char *)ip);
406 break;
407
408 case IPPROTO_ND:
409 printf("%s > %s:", ipaddr_string(&ip->ip_src),
410 ipaddr_string(&ip->ip_dst));
411 printf(" nd %d", len);
412 break;
413
414 #ifndef IPPROTO_OSPF
415 #define IPPROTO_OSPF 89
416 #endif
417 case IPPROTO_OSPF:
418 ospf_print(cp, len, (const u_char *)ip);
419 break;
420
421 #ifndef IPPROTO_IGMP
422 #define IPPROTO_IGMP 2
423 #endif
424 case IPPROTO_IGMP:
425 igmp_print(cp, len, (const u_char *)ip);
426 break;
427
428 #ifndef IPPROTO_IPIP
429 #define IPPROTO_IPIP 4
430 #endif
431 case IPPROTO_IPIP:
432 /* ip-in-ip encapsulation */
433 if (vflag)
434 printf("%s > %s: ",
435 ipaddr_string(&ip->ip_src),
436 ipaddr_string(&ip->ip_dst));
437 ip_print(cp, len);
438 if (! vflag) {
439 printf(" (encap)");
440 goto out;
441 }
442 break;
443
444 #ifndef IPPROTO_IPV6
445 #define IPPROTO_IPV6 41
446 #endif
447 case IPPROTO_IPV6:
448 /* ip6-in-ip encapsulation */
449 if (vflag)
450 printf("%s > %s: ",
451 ipaddr_string(&ip->ip_src),
452 ipaddr_string(&ip->ip_dst));
453 ip6_print(cp, len);
454 if (! vflag) {
455 printf(" (encap)");
456 goto out;
457 }
458 break;
459
460 #ifndef IPPROTO_GRE
461 #define IPPROTO_GRE 47
462 #endif
463 case IPPROTO_GRE:
464 printf("%s > %s: ",
465 ipaddr_string(&ip->ip_src),
466 ipaddr_string(&ip->ip_dst));
467 /* do it */
468 gre_print(cp, len);
469 break;
470
471 #ifndef IPPROTO_ESP
472 #define IPPROTO_ESP 50
473 #endif
474 case IPPROTO_ESP:
475 printf("%s > %s: ",
476 ipaddr_string(&ip->ip_src),
477 ipaddr_string(&ip->ip_dst));
478 esp_print(cp, len, (const u_char *)ip);
479 break;
480
481 #ifndef IPPROTO_AH
482 #define IPPROTO_AH 51
483 #endif
484 case IPPROTO_AH:
485 ah_print(cp, len, (const u_char *)ip);
486 break;
487
488 #ifndef IPPROTO_MOBILE
489 #define IPPROTO_MOBILE 55
490 #endif
491 case IPPROTO_MOBILE:
492 if (vflag)
493 printf("mobile %s > %s: ",
494 ipaddr_string(&ip->ip_src),
495 ipaddr_string(&ip->ip_dst));
496 mobile_print(cp, len);
497 if (! vflag) {
498 printf(" (mobile encap)");
499 goto out;
500 }
501 break;
502
503 #ifndef IPPROTO_ETHERIP
504 #define IPPROTO_ETHERIP 97
505 #endif
506 case IPPROTO_ETHERIP:
507 printf("%s > %s: ",
508 ipaddr_string(&ip->ip_src),
509 ipaddr_string(&ip->ip_dst));
510 etherip_print(cp, snapend - cp, len);
511 break;
512
513 #ifndef IPPROTO_IPCOMP
514 #define IPPROTO_IPCOMP 108
515 #endif
516 case IPPROTO_IPCOMP:
517 ipcomp_print(cp, len, (const u_char *)ip);
518 break;
519
520 #ifndef IPPROTO_CARP
521 #define IPPROTO_CARP 112
522 #endif
523 case IPPROTO_CARP:
524 if (packettype == PT_VRRP) {
525 if (vflag)
526 printf("vrrp %s > %s: ",
527 ipaddr_string(&ip->ip_src),
528 ipaddr_string(&ip->ip_dst));
529 vrrp_print(cp, len, ip->ip_ttl);
530 } else {
531 if (vflag)
532 printf("carp %s > %s: ",
533 ipaddr_string(&ip->ip_src),
534 ipaddr_string(&ip->ip_dst));
535 carp_print(cp, len, ip->ip_ttl);
536 }
537 break;
538
539 #ifndef IPPROTO_PFSYNC
540 #define IPPROTO_PFSYNC 240
541 #endif
542 case IPPROTO_PFSYNC:
543 pfsync_ip_print(cp,
544 (int)(snapend - (u_char *)ip) - hlen,
545 (const u_char *)ip);
546 break;
547
548 default:
549 printf("%s > %s:",
550 ipaddr_string(&ip->ip_src),
551 ipaddr_string(&ip->ip_dst));
552 printf(" ip-proto-%d %d", ip->ip_p, len);
553 break;
554 }
555 }
556 /*
557 * for fragmented datagrams, print id:size@offset. On all
558 * but the last stick a "+". For unfragmented datagrams, note
559 * the don't fragment flag.
560 */
561 if (off & 0x3fff) {
562 /*
563 * if this isn't the first frag, we're missing the
564 * next level protocol header. print the ip addr.
565 */
566 if (off & 0x1fff)
567 printf("%s > %s:",
568 ipaddr_string(&ip->ip_src),
569 ipaddr_string(&ip->ip_dst));
570 printf(" (frag %d:%d@%d%s)",
571 ntohs(ip->ip_id), len,
572 (off & 0x1fff) * 8,
573 (off & IP_MF)? "+" : "");
574 }
575 if (off & IP_DF)
576 printf(" (DF)");
577
578 if (ip->ip_tos) {
579 printf(" [tos 0x%x", (int)ip->ip_tos);
580 if (ip->ip_tos & (IPTOS_CE|IPTOS_ECT)) {
581 printf(" (");
582 if (ip->ip_tos & IPTOS_ECT) {
583 /* ECN-capable transport */
584 putchar('E');
585 }
586 if (ip->ip_tos & IPTOS_CE) {
587 /* _C_ongestion experienced (ECN) */
588 putchar('C');
589 }
590 printf(")");
591 }
592 printf("]");
593 }
594
595 if (ip->ip_ttl <= 1)
596 printf(" [ttl %d]", (int)ip->ip_ttl);
597
598 if (vflag) {
599 char *sep = "";
600
601 printf(" (");
602 if (ip->ip_ttl > 1) {
603 printf("%sttl %d", sep, (int)ip->ip_ttl);
604 sep = ", ";
605 }
606 if ((off & 0x3fff) == 0) {
607 printf("%sid %d", sep, (int)ntohs(ip->ip_id));
608 sep = ", ";
609 }
610 printf("%slen %u", sep, ntohs(ip->ip_len));
611 sep = ", ";
612 if ((u_char *)ip + hlen <= snapend) {
613 u_int16_t sum, ip_sum;
614 sum = in_cksum((const u_short *)ip, hlen, 0);
615 if (sum != 0) {
616 ip_sum = EXTRACT_16BITS(&ip->ip_sum);
617 printf("%sbad ip cksum %x! -> %x", sep, ip_sum,
618 in_cksum_shouldbe(ip_sum, sum));
619 sep = ", ";
620 }
621 }
622 if (hlen > sizeof(struct ip)) {
623 hlen -= sizeof(struct ip);
624 printf("%soptlen=%d", sep, hlen);
625 ip_optprint((u_char *)(ip + 1), hlen);
626 }
627 printf(")");
628 }
629 out:
630 packetp = pktp;
631 snapend = send;
632 return;
633
634 trunc:
635 printf("[|ip]");
636 }
637