print-ip6.c revision 1.5 
1/*
2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
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
16 * written permission.
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.
20 */
21
22#include <sys/cdefs.h>
23#ifndef lint
24__RCSID("$NetBSD: print-ip6.c,v 1.5 2015/03/31 21:59:35 christos Exp $");
25#endif
26
27#define NETDISSECT_REWORKED
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include <tcpdump-stdinc.h>
33
34#include <string.h>
35
36#include "interface.h"
37#include "addrtoname.h"
38#include "extract.h"
39
40#ifdef INET6
41
42#include "ip6.h"
43#include "ipproto.h"
44
45/*
46 * Compute a V6-style checksum by building a pseudoheader.
47 */
48int
49nextproto6_cksum(const struct ip6_hdr *ip6, const uint8_t *data,
50		 u_int len, u_int covlen, u_int next_proto)
51{
52        struct {
53                struct in6_addr ph_src;
54                struct in6_addr ph_dst;
55                uint32_t       ph_len;
56                uint8_t        ph_zero[3];
57                uint8_t        ph_nxt;
58        } ph;
59        struct cksum_vec vec[2];
60
61        /* pseudo-header */
62        memset(&ph, 0, sizeof(ph));
63        UNALIGNED_MEMCPY(&ph.ph_src, &ip6->ip6_src, sizeof (struct in6_addr));
64        UNALIGNED_MEMCPY(&ph.ph_dst, &ip6->ip6_dst, sizeof (struct in6_addr));
65        ph.ph_len = htonl(len);
66        ph.ph_nxt = next_proto;
67
68        vec[0].ptr = (const uint8_t *)(void *)&ph;
69        vec[0].len = sizeof(ph);
70        vec[1].ptr = data;
71        vec[1].len = covlen;
72
73        return in_cksum(vec, 2);
74}
75
76/*
77 * print an IP6 datagram.
78 */
79void
80ip6_print(netdissect_options *ndo, const u_char *bp, u_int length)
81{
82	register const struct ip6_hdr *ip6;
83	register int advance;
84	u_int len;
85	const u_char *ipend;
86	register const u_char *cp;
87	register u_int payload_len;
88	int nh;
89	int fragmented = 0;
90	u_int flow;
91
92	ip6 = (const struct ip6_hdr *)bp;
93
94	ND_TCHECK(*ip6);
95	if (length < sizeof (struct ip6_hdr)) {
96		ND_PRINT((ndo, "truncated-ip6 %u", length));
97		return;
98	}
99
100        if (!ndo->ndo_eflag)
101            ND_PRINT((ndo, "IP6 "));
102
103	if (IP6_VERSION(ip6) != 6) {
104          ND_PRINT((ndo,"version error: %u != 6", IP6_VERSION(ip6)));
105          return;
106	}
107
108	payload_len = EXTRACT_16BITS(&ip6->ip6_plen);
109	len = payload_len + sizeof(struct ip6_hdr);
110	if (length < len)
111		ND_PRINT((ndo, "truncated-ip6 - %u bytes missing!",
112			len - length));
113
114        if (ndo->ndo_vflag) {
115            flow = EXTRACT_32BITS(&ip6->ip6_flow);
116            ND_PRINT((ndo, "("));
117#if 0
118            /* rfc1883 */
119            if (flow & 0x0f000000)
120		ND_PRINT((ndo, "pri 0x%02x, ", (flow & 0x0f000000) >> 24));
121            if (flow & 0x00ffffff)
122		ND_PRINT((ndo, "flowlabel 0x%06x, ", flow & 0x00ffffff));
123#else
124            /* RFC 2460 */
125            if (flow & 0x0ff00000)
126		ND_PRINT((ndo, "class 0x%02x, ", (flow & 0x0ff00000) >> 20));
127            if (flow & 0x000fffff)
128		ND_PRINT((ndo, "flowlabel 0x%05x, ", flow & 0x000fffff));
129#endif
130
131            ND_PRINT((ndo, "hlim %u, next-header %s (%u) payload length: %u) ",
132                         ip6->ip6_hlim,
133                         tok2str(ipproto_values,"unknown",ip6->ip6_nxt),
134                         ip6->ip6_nxt,
135                         payload_len));
136        }
137
138	/*
139	 * Cut off the snapshot length to the end of the IP payload.
140	 */
141	ipend = bp + len;
142	if (ipend < ndo->ndo_snapend)
143		ndo->ndo_snapend = ipend;
144
145	cp = (const u_char *)ip6;
146	advance = sizeof(struct ip6_hdr);
147	nh = ip6->ip6_nxt;
148	while (cp < ndo->ndo_snapend && advance > 0) {
149		cp += advance;
150		len -= advance;
151
152		if (cp == (const u_char *)(ip6 + 1) &&
153		    nh != IPPROTO_TCP && nh != IPPROTO_UDP &&
154		    nh != IPPROTO_DCCP && nh != IPPROTO_SCTP) {
155			ND_PRINT((ndo, "%s > %s: ", ip6addr_string(ndo, &ip6->ip6_src),
156				     ip6addr_string(ndo, &ip6->ip6_dst)));
157		}
158
159		switch (nh) {
160		case IPPROTO_HOPOPTS:
161			advance = hbhopt_print(ndo, cp);
162			nh = *cp;
163			break;
164		case IPPROTO_DSTOPTS:
165			advance = dstopt_print(ndo, cp);
166			nh = *cp;
167			break;
168		case IPPROTO_FRAGMENT:
169			advance = frag6_print(ndo, cp, (const u_char *)ip6);
170			if (ndo->ndo_snapend <= cp + advance)
171				return;
172			nh = *cp;
173			fragmented = 1;
174			break;
175
176		case IPPROTO_MOBILITY_OLD:
177		case IPPROTO_MOBILITY:
178			/*
179			 * XXX - we don't use "advance"; the current
180			 * "Mobility Support in IPv6" draft
181			 * (draft-ietf-mobileip-ipv6-24) says that
182			 * the next header field in a mobility header
183			 * should be IPPROTO_NONE, but speaks of
184			 * the possiblity of a future extension in
185			 * which payload can be piggybacked atop a
186			 * mobility header.
187			 */
188			advance = mobility_print(ndo, cp, (const u_char *)ip6);
189			nh = *cp;
190			return;
191		case IPPROTO_ROUTING:
192			advance = rt6_print(ndo, cp, (const u_char *)ip6);
193			nh = *cp;
194			break;
195		case IPPROTO_SCTP:
196			sctp_print(ndo, cp, (const u_char *)ip6, len);
197			return;
198		case IPPROTO_DCCP:
199			dccp_print(ndo, cp, (const u_char *)ip6, len);
200			return;
201		case IPPROTO_TCP:
202			tcp_print(ndo, cp, len, (const u_char *)ip6, fragmented);
203			return;
204		case IPPROTO_UDP:
205			udp_print(ndo, cp, len, (const u_char *)ip6, fragmented);
206			return;
207		case IPPROTO_ICMPV6:
208			icmp6_print(ndo, cp, len, (const u_char *)ip6, fragmented);
209			return;
210		case IPPROTO_AH:
211			advance = ah_print(ndo, cp);
212			nh = *cp;
213			break;
214		case IPPROTO_ESP:
215		    {
216			int enh, padlen;
217			advance = esp_print(ndo, cp, len, (const u_char *)ip6, &enh, &padlen);
218			nh = enh & 0xff;
219			len -= padlen;
220			break;
221		    }
222		case IPPROTO_IPCOMP:
223		    {
224			int enh;
225			advance = ipcomp_print(ndo, cp, &enh);
226			nh = enh & 0xff;
227			break;
228		    }
229
230		case IPPROTO_PIM:
231			pim_print(ndo, cp, len, nextproto6_cksum(ip6, cp, len, len,
232							    IPPROTO_PIM));
233			return;
234
235		case IPPROTO_OSPF:
236			ospf6_print(ndo, cp, len);
237			return;
238
239		case IPPROTO_IPV6:
240			ip6_print(ndo, cp, len);
241			return;
242
243		case IPPROTO_IPV4:
244		        ip_print(ndo, cp, len);
245			return;
246
247                case IPPROTO_PGM:
248                        pgm_print(ndo, cp, len, (const u_char *)ip6);
249                        return;
250
251		case IPPROTO_GRE:
252			gre_print(ndo, cp, len);
253			return;
254
255		case IPPROTO_RSVP:
256			rsvp_print(ndo, cp, len);
257			return;
258
259		case IPPROTO_NONE:
260			ND_PRINT((ndo, "no next header"));
261			return;
262
263		default:
264			ND_PRINT((ndo, "ip-proto-%d %d", nh, len));
265			return;
266		}
267	}
268
269	return;
270trunc:
271	ND_PRINT((ndo, "[|ip6]"));
272}
273
274#else /* INET6 */
275
276void
277ip6_print(netdissect_options *ndo, const u_char *bp _U_, u_int length)
278{
279	ND_PRINT((ndo, "IP6, length: %u (printing not supported)", length));
280}
281
282#endif /* INET6 */
283