2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
25 static const char rcsid
[] _U_
=
26 "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.149.2.9 2007/09/14 01:30:02 guy Exp $ (LBL)";
33 #include <tcpdump-stdinc.h>
39 #include "addrtoname.h"
40 #include "interface.h"
41 #include "extract.h" /* must come after interface.h */
46 struct tok ip_option_values
[] = {
49 { IPOPT_TS
, "timestamp" },
50 { IPOPT_SECURITY
, "security" },
52 { IPOPT_SSRR
, "SSRR" },
53 { IPOPT_LSRR
, "LSRR" },
55 { IPOPT_RFC1393
, "traceroute" },
60 * print the recorded route in an IP RR, LSRR or SSRR option.
63 ip_printroute(register const u_char
*cp
, u_int length
)
69 printf(" [bad length %u]", length
);
73 printf(" [bad length %u]", length
);
75 if (ptr
< 3 || ((ptr
+ 1) & 3) || ptr
> length
+ 1)
76 printf(" [bad ptr %u]", cp
[2]);
78 for (len
= 3; len
< length
; len
+= 4) {
79 printf(" %s", ipaddr_string(&cp
[len
]));
86 * If source-routing is present and valid, return the final destination.
87 * Otherwise, return IP destination.
89 * This is used for UDP and TCP pseudo-header in the checksum
93 ip_finddst(const struct ip
*ip
)
100 cp
= (const u_char
*)(ip
+ 1);
101 length
= (IP_HL(ip
) << 2) - sizeof(struct ip
);
103 for (; length
> 0; cp
+= len
, length
-= len
) {
110 else if (tt
== IPOPT_NOP
)
125 memcpy(&retval
, cp
+ len
- 4, 4);
130 memcpy(&retval
, &ip
->ip_dst
.s_addr
, sizeof(u_int32_t
));
135 ip_printts(register const u_char
*cp
, u_int length
)
143 printf("[bad length %u]", length
);
147 hoplen
= ((cp
[3]&0xF) != IPOPT_TS_TSONLY
) ? 8 : 4;
148 if ((length
- 4) & (hoplen
-1))
149 printf("[bad length %u]", length
);
152 if (ptr
< 4 || ((ptr
- 4) & (hoplen
-1)) || ptr
> length
+ 1)
153 printf("[bad ptr %u]", cp
[2]);
155 case IPOPT_TS_TSONLY
:
158 case IPOPT_TS_TSANDADDR
:
162 * prespecified should really be 3, but some ones might send 2
163 * instead, and the IPOPT_TS_PRESPEC constant can apparently
164 * have both values, so we have to hard-code it here.
168 printf("PRESPEC2.0");
170 case 3: /* IPOPT_TS_PRESPEC */
174 printf("[bad ts type %d]", cp
[3]&0xF);
179 for (len
= 4; len
< length
; len
+= hoplen
) {
182 printf("%s%d@%s", type
, EXTRACT_32BITS(&cp
[len
+hoplen
-4]),
183 hoplen
!=8 ? "" : ipaddr_string(&cp
[len
]));
188 printf("%s", ptr
== len
? " ^ " : "");
191 printf(" [%d hops not recorded]} ", cp
[3]>>4);
200 ip_optprint(register const u_char
*cp
, u_int length
)
202 register u_int option_len
;
203 const char *sep
= "";
205 for (; length
> 0; cp
+= option_len
, length
-= option_len
) {
215 tok2str(ip_option_values
,"unknown %u",option_code
));
217 if (option_code
== IPOPT_NOP
||
218 option_code
== IPOPT_EOL
)
224 if (option_len
< 2) {
225 printf(" [bad length %u]", option_len
);
230 if (option_len
> length
) {
231 printf(" [bad length %u]", option_len
);
235 TCHECK2(*cp
, option_len
);
237 switch (option_code
) {
242 ip_printts(cp
, option_len
);
245 case IPOPT_RR
: /* fall through */
248 ip_printroute(cp
, option_len
);
252 if (option_len
< 4) {
253 printf(" [bad length %u]", option_len
);
257 if (EXTRACT_16BITS(&cp
[2]) != 0)
258 printf(" value %u", EXTRACT_16BITS(&cp
[2]));
261 case IPOPT_NOP
: /* nothing to print - fall through */
274 * compute an IP header checksum.
275 * don't modifiy the packet.
278 in_cksum(const u_short
*addr
, register u_int len
, int csum
)
281 const u_short
*w
= addr
;
286 * Our algorithm is simple, using a 32 bit accumulator (sum),
287 * we add sequential 16 bit words to it, and at the end, fold
288 * back all the carry bits from the top 16 bits into the lower
296 sum
+= htons(*(u_char
*)w
<<8);
299 * add back carry outs from top 16 bits to low 16 bits
301 sum
= (sum
>> 16) + (sum
& 0xffff); /* add hi 16 to low 16 */
302 sum
+= (sum
>> 16); /* add carry */
303 answer
= ~sum
; /* truncate to 16 bits */
308 * Given the host-byte-order value of the checksum field in a packet
309 * header, and the network-byte-order computed checksum of the data
310 * that the checksum covers (including the checksum itself), compute
311 * what the checksum field *should* have been.
314 in_cksum_shouldbe(u_int16_t sum
, u_int16_t computed_sum
)
319 * The value that should have gone into the checksum field
320 * is the negative of the value gotten by summing up everything
321 * *but* the checksum field.
323 * We can compute that by subtracting the value of the checksum
324 * field from the sum of all the data in the packet, and then
325 * computing the negative of that value.
327 * "sum" is the value of the checksum field, and "computed_sum"
328 * is the negative of the sum of all the data in the packets,
329 * so that's -(-computed_sum - sum), or (sum + computed_sum).
331 * All the arithmetic in question is one's complement, so the
332 * addition must include an end-around carry; we do this by
333 * doing the arithmetic in 32 bits (with no sign-extension),
334 * and then adding the upper 16 bits of the sum, which contain
335 * the carry, to the lower 16 bits of the sum, and then do it
336 * again in case *that* sum produced a carry.
338 * As RFC 1071 notes, the checksum can be computed without
339 * byte-swapping the 16-bit words; summing 16-bit words
340 * on a big-endian machine gives a big-endian checksum, which
341 * can be directly stuffed into the big-endian checksum fields
342 * in protocol headers, and summing words on a little-endian
343 * machine gives a little-endian checksum, which must be
344 * byte-swapped before being stuffed into a big-endian checksum
347 * "computed_sum" is a network-byte-order value, so we must put
348 * it in host byte order before subtracting it from the
349 * host-byte-order value from the header; the adjusted checksum
350 * will be in host byte order, which is what we'll return.
353 shouldbe
+= ntohs(computed_sum
);
354 shouldbe
= (shouldbe
& 0xFFFF) + (shouldbe
>> 16);
355 shouldbe
= (shouldbe
& 0xFFFF) + (shouldbe
>> 16);
359 #define IP_RES 0x8000
361 static struct tok ip_frag_values
[] = {
364 { IP_RES
, "rsvd" }, /* The RFC3514 evil ;-) bit */
368 struct ip_print_demux_state
{
377 ip_print_demux(netdissect_options
*ndo
,
378 struct ip_print_demux_state
*ipds
)
380 struct protoent
*proto
;
386 ipds
->nh
= *ipds
->cp
;
387 ipds
->advance
= ah_print(ipds
->cp
);
388 if (ipds
->advance
<= 0)
390 ipds
->cp
+= ipds
->advance
;
391 ipds
->len
-= ipds
->advance
;
397 ipds
->advance
= esp_print(ndo
, ipds
->cp
, ipds
->len
,
398 (const u_char
*)ipds
->ip
,
400 if (ipds
->advance
<= 0)
402 ipds
->cp
+= ipds
->advance
;
403 ipds
->len
-= ipds
->advance
+ padlen
;
404 ipds
->nh
= enh
& 0xff;
411 ipds
->advance
= ipcomp_print(ipds
->cp
, &enh
);
412 if (ipds
->advance
<= 0)
414 ipds
->cp
+= ipds
->advance
;
415 ipds
->len
-= ipds
->advance
;
416 ipds
->nh
= enh
& 0xff;
421 sctp_print(ipds
->cp
, (const u_char
*)ipds
->ip
, ipds
->len
);
425 dccp_print(ipds
->cp
, (const u_char
*)ipds
->ip
, ipds
->len
);
429 /* pass on the MF bit plus the offset to detect fragments */
430 tcp_print(ipds
->cp
, ipds
->len
, (const u_char
*)ipds
->ip
,
431 ipds
->off
& (IP_MF
|IP_OFFMASK
));
435 /* pass on the MF bit plus the offset to detect fragments */
436 udp_print(ipds
->cp
, ipds
->len
, (const u_char
*)ipds
->ip
,
437 ipds
->off
& (IP_MF
|IP_OFFMASK
));
441 /* pass on the MF bit plus the offset to detect fragments */
442 icmp_print(ipds
->cp
, ipds
->len
, (const u_char
*)ipds
->ip
,
443 ipds
->off
& (IP_MF
|IP_OFFMASK
));
448 * XXX - the current IANA protocol number assignments
449 * page lists 9 as "any private interior gateway
450 * (used by Cisco for their IGRP)" and 88 as
451 * "EIGRP" from Cisco.
453 * Recent BSD <netinet/in.h> headers define
454 * IP_PROTO_PIGP as 9 and IP_PROTO_IGRP as 88.
455 * We define IP_PROTO_PIGP as 9 and
456 * IP_PROTO_EIGRP as 88; those names better
457 * match was the current protocol number
460 igrp_print(ipds
->cp
, ipds
->len
, (const u_char
*)ipds
->ip
);
464 eigrp_print(ipds
->cp
, ipds
->len
);
468 ND_PRINT((ndo
, " nd %d", ipds
->len
));
472 egp_print(ipds
->cp
, ipds
->len
);
476 ospf_print(ipds
->cp
, ipds
->len
, (const u_char
*)ipds
->ip
);
480 igmp_print(ipds
->cp
, ipds
->len
);
484 /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
485 ip_print(gndo
, ipds
->cp
, ipds
->len
);
487 ND_PRINT((ndo
, " (ipip-proto-4)"));
494 /* ip6-in-ip encapsulation */
495 ip6_print(ipds
->cp
, ipds
->len
);
500 rsvp_print(ipds
->cp
, ipds
->len
);
505 gre_print(ipds
->cp
, ipds
->len
);
509 mobile_print(ipds
->cp
, ipds
->len
);
513 pim_print(ipds
->cp
, ipds
->len
);
517 vrrp_print(ipds
->cp
, ipds
->len
, ipds
->ip
->ip_ttl
);
521 pgm_print(ipds
->cp
, ipds
->len
, (const u_char
*)ipds
->ip
);
525 if ((proto
= getprotobynumber(ipds
->nh
)) != NULL
)
526 ND_PRINT((ndo
, " %s", proto
->p_name
));
528 ND_PRINT((ndo
, " ip-proto-%d", ipds
->nh
));
529 ND_PRINT((ndo
, " %d", ipds
->len
));
535 ip_print_inner(netdissect_options
*ndo
,
537 u_int length
, u_int nh
,
540 struct ip_print_demux_state ipd
;
542 ipd
.ip
= (const struct ip
*)bp2
;
549 ip_print_demux(ndo
, &ipd
);
554 * print an IP datagram.
557 ip_print(netdissect_options
*ndo
,
561 struct ip_print_demux_state ipd
;
562 struct ip_print_demux_state
*ipds
=&ipd
;
565 u_int16_t sum
, ip_sum
;
566 struct protoent
*proto
;
568 ipds
->ip
= (const struct ip
*)bp
;
569 if (IP_V(ipds
->ip
) != 4) { /* print version if != 4 */
570 printf("IP%u ", IP_V(ipds
->ip
));
571 if (IP_V(ipds
->ip
) == 6)
572 printf(", wrong link-layer encapsulation");
577 if ((u_char
*)(ipds
->ip
+ 1) > snapend
) {
581 if (length
< sizeof (struct ip
)) {
582 (void)printf("truncated-ip %u", length
);
585 hlen
= IP_HL(ipds
->ip
) * 4;
586 if (hlen
< sizeof (struct ip
)) {
587 (void)printf("bad-hlen %u", hlen
);
591 ipds
->len
= EXTRACT_16BITS(&ipds
->ip
->ip_len
);
592 if (length
< ipds
->len
)
593 (void)printf("truncated-ip - %u bytes missing! ",
595 if (ipds
->len
< hlen
) {
598 (void)printf("bad-len %u", ipds
->len
);
602 /* we guess that it is a TSO send */
606 (void)printf("bad-len %u", ipds
->len
);
608 #endif /* GUESS_TSO */
612 * Cut off the snapshot length to the end of the IP payload.
614 ipend
= bp
+ ipds
->len
;
620 ipds
->off
= EXTRACT_16BITS(&ipds
->ip
->ip_off
);
623 (void)printf("(tos 0x%x", (int)ipds
->ip
->ip_tos
);
625 if (ipds
->ip
->ip_tos
& 0x03) {
626 switch (ipds
->ip
->ip_tos
& 0x03) {
628 (void)printf(",ECT(1)");
631 (void)printf(",ECT(0)");
638 if (ipds
->ip
->ip_ttl
>= 1)
639 (void)printf(", ttl %u", ipds
->ip
->ip_ttl
);
642 * for the firewall guys, print id, offset.
643 * On all but the last stick a "+" in the flags portion.
644 * For unfragmented datagrams, note the don't fragment flag.
647 (void)printf(", id %u, offset %u, flags [%s], proto %s (%u)",
648 EXTRACT_16BITS(&ipds
->ip
->ip_id
),
649 (ipds
->off
& 0x1fff) * 8,
650 bittok2str(ip_frag_values
, "none", ipds
->off
&0xe000),
651 tok2str(ipproto_values
,"unknown",ipds
->ip
->ip_p
),
654 (void)printf(", length %u", EXTRACT_16BITS(&ipds
->ip
->ip_len
));
656 if ((hlen
- sizeof(struct ip
)) > 0) {
657 printf(", options (");
658 ip_optprint((u_char
*)(ipds
->ip
+ 1), hlen
- sizeof(struct ip
));
662 if ((u_char
*)ipds
->ip
+ hlen
<= snapend
) {
663 sum
= in_cksum((const u_short
*)ipds
->ip
, hlen
, 0);
665 ip_sum
= EXTRACT_16BITS(&ipds
->ip
->ip_sum
);
666 (void)printf(", bad cksum %x (->%x)!", ip_sum
,
667 in_cksum_shouldbe(ip_sum
, sum
));
675 * If this is fragment zero, hand it to the next higher
678 if ((ipds
->off
& 0x1fff) == 0) {
679 ipds
->cp
= (const u_char
*)ipds
->ip
+ hlen
;
680 ipds
->nh
= ipds
->ip
->ip_p
;
682 if (ipds
->nh
!= IPPROTO_TCP
&& ipds
->nh
!= IPPROTO_UDP
&&
683 ipds
->nh
!= IPPROTO_SCTP
&& ipds
->nh
!= IPPROTO_DCCP
) {
684 (void)printf("%s > %s: ",
685 ipaddr_string(&ipds
->ip
->ip_src
),
686 ipaddr_string(&ipds
->ip
->ip_dst
));
688 ip_print_demux(ndo
, ipds
);
690 /* Ultra quiet now means that all this stuff should be suppressed */
691 if (qflag
> 1) return;
694 * if this isn't the first frag, we're missing the
695 * next level protocol header. print the ip addr
698 if (ipds
->off
& 0x1fff) {
699 (void)printf("%s > %s:", ipaddr_string(&ipds
->ip
->ip_src
),
700 ipaddr_string(&ipds
->ip
->ip_dst
));
701 if ((proto
= getprotobynumber(ipds
->ip
->ip_p
)) != NULL
)
702 (void)printf(" %s", proto
->p_name
);
704 (void)printf(" ip-proto-%d", ipds
->ip
->ip_p
);
710 ipN_print(register const u_char
*bp
, register u_int length
)
714 ip
= (struct ip
*)bp
;
716 (void)printf("truncated-ip %d", length
);
719 memcpy (&hdr
, (char *)ip
, 4);
720 switch (IP_V(&hdr
)) {
722 ip_print (gndo
, bp
, length
);
726 ip6_print (bp
, length
);
730 (void)printf("unknown ip %d", IP_V(&hdr
));
737 * c-style: whitesmith