print-ether.c revision 111729 
1/*
2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
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 * $FreeBSD: head/contrib/tcpdump/print-ether.c 111729 2003-03-02 08:25:48Z fenner $
22 */
23#ifndef lint
24static const char rcsid[] =
25    "@(#) $Header: /tcpdump/master/tcpdump/print-ether.c,v 1.65.4.1 2002/06/01 23:51:12 guy Exp $ (LBL)";
26#endif
27
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include <sys/param.h>
33#include <sys/time.h>
34#include <sys/socket.h>
35
36#include <netinet/in.h>
37
38#include <stdio.h>
39#include <pcap.h>
40
41#include "interface.h"
42#include "addrtoname.h"
43#include "ethertype.h"
44
45#include "ether.h"
46
47const u_char *packetp;
48const u_char *snapend;
49
50static inline void
51ether_print(register const u_char *bp, u_int length)
52{
53	register const struct ether_header *ep;
54
55	ep = (const struct ether_header *)bp;
56	if (qflag)
57		(void)printf("%s %s %d: ",
58			     etheraddr_string(ESRC(ep)),
59			     etheraddr_string(EDST(ep)),
60			     length);
61	else
62		(void)printf("%s %s %s %d: ",
63			     etheraddr_string(ESRC(ep)),
64			     etheraddr_string(EDST(ep)),
65			     etherproto_string(ep->ether_type),
66			     length);
67}
68
69/*
70 * This is the top level routine of the printer.  'p' is the points
71 * to the ether header of the packet, 'h->tv' is the timestamp,
72 * 'h->length' is the length of the packet off the wire, and 'h->caplen'
73 * is the number of bytes actually captured.
74 */
75void
76ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
77{
78	u_int caplen = h->caplen;
79	u_int length = h->len;
80	struct ether_header *ep;
81	u_short ether_type;
82	u_short extracted_ethertype;
83
84	++infodelay;
85	ts_print(&h->ts);
86
87	if (caplen < ETHER_HDRLEN) {
88		printf("[|ether]");
89		goto out;
90	}
91
92	if (eflag)
93		ether_print(p, length);
94
95	/*
96	 * Some printers want to get back at the ethernet addresses,
97	 * and/or check that they're not walking off the end of the packet.
98	 * Rather than pass them all the way down, we set these globals.
99	 */
100	packetp = p;
101	snapend = p + caplen;
102
103	length -= ETHER_HDRLEN;
104	caplen -= ETHER_HDRLEN;
105	ep = (struct ether_header *)p;
106	p += ETHER_HDRLEN;
107
108	ether_type = ntohs(ep->ether_type);
109
110	/*
111	 * Is it (gag) an 802.3 encapsulation?
112	 */
113	extracted_ethertype = 0;
114	if (ether_type <= ETHERMTU) {
115		/* Try to print the LLC-layer header & higher layers */
116		if (llc_print(p, length, caplen, ESRC(ep), EDST(ep),
117		    &extracted_ethertype) == 0) {
118			/* ether_type not known, print raw packet */
119			if (!eflag)
120				ether_print((u_char *)ep, length + ETHER_HDRLEN);
121			if (extracted_ethertype) {
122				printf("(LLC %s) ",
123			       etherproto_string(htons(extracted_ethertype)));
124			}
125			if (!xflag && !qflag)
126				default_print(p, caplen);
127		}
128	} else if (ether_encap_print(ether_type, p, length, caplen,
129	    &extracted_ethertype) == 0) {
130		/* ether_type not known, print raw packet */
131		if (!eflag)
132			ether_print((u_char *)ep, length + ETHER_HDRLEN);
133		if (!xflag && !qflag)
134			default_print(p, caplen);
135	}
136	if (xflag)
137		default_print(p, caplen);
138 out:
139	putchar('\n');
140	--infodelay;
141	if (infoprint)
142		info(0);
143}
144
145/*
146 * Prints the packet encapsulated in an Ethernet data segment
147 * (or an equivalent encapsulation), given the Ethernet type code.
148 *
149 * Returns non-zero if it can do so, zero if the ethertype is unknown.
150 *
151 * The Ethernet type code is passed through a pointer; if it was
152 * ETHERTYPE_8021Q, it gets updated to be the Ethernet type of
153 * the 802.1Q payload, for the benefit of lower layers that might
154 * want to know what it is.
155 */
156
157int
158ether_encap_print(u_short ethertype, const u_char *p,
159    u_int length, u_int caplen, u_short *extracted_ethertype)
160{
161 recurse:
162	*extracted_ethertype = ethertype;
163
164	switch (ethertype) {
165
166	case ETHERTYPE_IP:
167		ip_print(p, length);
168		return (1);
169
170#ifdef INET6
171	case ETHERTYPE_IPV6:
172		ip6_print(p, length);
173		return (1);
174#endif /*INET6*/
175
176	case ETHERTYPE_ARP:
177	case ETHERTYPE_REVARP:
178		arp_print(p, length, caplen);
179		return (1);
180
181	case ETHERTYPE_DN:
182		decnet_print(p, length, caplen);
183		return (1);
184
185	case ETHERTYPE_ATALK:
186		if (vflag)
187			fputs("et1 ", stdout);
188		atalk_print(p, length);
189		return (1);
190
191	case ETHERTYPE_AARP:
192		aarp_print(p, length);
193		return (1);
194
195	case ETHERTYPE_IPX:
196		ipx_print(p, length);
197		return (1);
198
199	case ETHERTYPE_8021Q:
200		printf("802.1Q vlan#%d P%d%s ",
201		       ntohs(*(u_int16_t *)p) & 0xfff,
202		       ntohs(*(u_int16_t *)p) >> 13,
203		       (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
204		ethertype = ntohs(*(u_int16_t *)(p + 2));
205		p += 4;
206		length -= 4;
207		caplen -= 4;
208		if (ethertype > ETHERMTU)
209			goto recurse;
210
211		*extracted_ethertype = 0;
212
213		if (llc_print(p, length, caplen, p - 18, p - 12,
214		    extracted_ethertype) == 0) {
215			/* ether_type not known, print raw packet */
216			if (!eflag)
217				ether_print(p - 18, length + 4);
218			if (*extracted_ethertype) {
219				printf("(LLC %s) ",
220			       etherproto_string(htons(*extracted_ethertype)));
221			}
222			if (!xflag && !qflag)
223				default_print(p - 18, caplen + 4);
224		}
225		return (1);
226
227	case ETHERTYPE_PPPOED:
228	case ETHERTYPE_PPPOES:
229	case ETHERTYPE_PPPOED2:
230	case ETHERTYPE_PPPOES2:
231		pppoe_print(p, length);
232 		return (1);
233
234	case ETHERTYPE_PPP:
235		printf("ppp");
236		if (length) {
237			printf(": ");
238			ppp_print(p, length);
239		}
240		return (1);
241
242	case ETHERTYPE_MPLS:
243	case ETHERTYPE_MPLS_MULTI:
244		mpls_print(p, length);
245		return (1);
246
247	case ETHERTYPE_LAT:
248	case ETHERTYPE_SCA:
249	case ETHERTYPE_MOPRC:
250	case ETHERTYPE_MOPDL:
251		/* default_print for now */
252	default:
253		return (0);
254	}
255}
256