xref: /openbsd-src/usr.sbin/tcpdump/print-ether.c (revision 2777ee89d0e541ec819d05abee114837837abbec)
1 /*	$OpenBSD: print-ether.c,v 1.30 2015/11/16 00:16:39 mmcc 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 struct mbuf;
28 struct rtentry;
29 #include <net/if.h>
30 
31 #include <netinet/in.h>
32 #include <netinet/if_ether.h>
33 #include <netinet/ip.h>
34 #include <netinet/ip_var.h>
35 #include <netinet/udp.h>
36 #include <netinet/udp_var.h>
37 #include <netinet/tcp.h>
38 
39 #include <stdio.h>
40 #include <pcap.h>
41 
42 #ifdef INET6
43 #include <netinet/ip6.h>
44 #endif
45 
46 #include "interface.h"
47 #include "addrtoname.h"
48 #include "ethertype.h"
49 #include "extract.h"
50 
51 const u_char *packetp;
52 const u_char *snapend;
53 
54 void ether_macctl(const u_char *, u_int);
55 
56 void
57 ether_print(const u_char *bp, u_int length)
58 {
59 	const struct ether_header *ep;
60 
61 	ep = (const struct ether_header *)bp;
62 	if (qflag) {
63 		TCHECK2(*ep, 12);
64 		(void)printf("%s %s %d: ",
65 			     etheraddr_string(ESRC(ep)),
66 			     etheraddr_string(EDST(ep)),
67 			     length);
68 	} else {
69 		TCHECK2(*ep, 14);
70 		(void)printf("%s %s %s %d: ",
71 			     etheraddr_string(ESRC(ep)),
72 			     etheraddr_string(EDST(ep)),
73 			     etherproto_string(ep->ether_type),
74 			     length);
75 	}
76 	return;
77 trunc:
78 	printf("[|ether] ");
79 }
80 
81 u_short extracted_ethertype;
82 
83 /*
84  * This is the top level routine of the printer.  'p' is the points
85  * to the ether header of the packet, 'tvp' is the timestamp,
86  * 'length' is the length of the packet off the wire, and 'caplen'
87  * is the number of bytes actually captured.
88  */
89 void
90 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
91 {
92 	u_int caplen = h->caplen;
93 	u_int length = h->len;
94 	struct ether_header *ep;
95 	u_short ether_type;
96 
97 	ts_print(&h->ts);
98 
99 	if (caplen < sizeof(struct ether_header)) {
100 		printf("[|ether]");
101 		goto out;
102 	}
103 
104 	/*
105 	 * Some printers want to get back at the ethernet addresses,
106 	 * and/or check that they're not walking off the end of the packet.
107 	 * Rather than pass them all the way down, we set these globals.
108 	 */
109 	packetp = p;
110 	snapend = p + caplen;
111 
112 	if (eflag)
113 		ether_print(p, length);
114 
115 	length -= sizeof(struct ether_header);
116 	caplen -= sizeof(struct ether_header);
117 	ep = (struct ether_header *)p;
118 	p += sizeof(struct ether_header);
119 
120 	ether_type = ntohs(ep->ether_type);
121 
122 	/*
123 	 * Is it (gag) an 802.3 encapsulation?
124 	 */
125 	extracted_ethertype = 0;
126 	if (ether_type <= ETHERMTU) {
127 		/* Try to print the LLC-layer header & higher layers */
128 		if (llc_print(p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
129 			/* ether_type not known, print raw packet */
130 			if (!eflag)
131 				ether_print((u_char *)ep, length);
132 			if (extracted_ethertype) {
133 				printf("(LLC %s) ",
134 			       etherproto_string(htons(extracted_ethertype)));
135 			}
136 			if (!xflag && !qflag) {
137 				if (eflag)
138 					default_print(packetp,
139 					    snapend - packetp);
140 				else
141 					default_print(p, caplen);
142 			}
143 		}
144 	} else if (ether_encap_print(ether_type, p, length, caplen) == 0) {
145 		/* ether_type not known, print raw packet */
146 		if (!eflag)
147 			ether_print((u_char *)ep, length + sizeof(*ep));
148 		if (!xflag && !qflag) {
149 			if (eflag)
150 				default_print(packetp, snapend - packetp);
151 			else
152 				default_print(p, caplen);
153 		}
154 	}
155 	if (xflag) {
156 		if (eflag)
157 			default_print(packetp, snapend - packetp);
158 		else
159 			default_print(p, caplen);
160 	}
161  out:
162 	putchar('\n');
163 }
164 
165 /*
166  * Prints the packet encapsulated in an Ethernet data segment
167  * (or an equivalent encapsulation), given the Ethernet type code.
168  *
169  * Returns non-zero if it can do so, zero if the ethertype is unknown.
170  *
171  * Stuffs the ether type into a global for the benefit of lower layers
172  * that might want to know what it is.
173  */
174 
175 int
176 ether_encap_print(u_short ethertype, const u_char *p,
177     u_int length, u_int caplen)
178 {
179 recurse:
180 	extracted_ethertype = ethertype;
181 
182 	switch (ethertype) {
183 
184 	case ETHERTYPE_IP:
185 		ip_print(p, length);
186 		return (1);
187 
188 #ifdef INET6
189 	case ETHERTYPE_IPV6:
190 		ip6_print(p, length);
191 		return (1);
192 #endif /*INET6*/
193 
194 	case ETHERTYPE_ARP:
195 	case ETHERTYPE_REVARP:
196 		arp_print(p, length, caplen);
197 		return (1);
198 
199 	case ETHERTYPE_DN:
200 		decnet_print(p, length, caplen);
201 		return (1);
202 
203 	case ETHERTYPE_ATALK:
204 		if (vflag)
205 			fputs("et1 ", stdout);
206 		atalk_print_llap(p, length);
207 		return (1);
208 
209 	case ETHERTYPE_AARP:
210 		aarp_print(p, length);
211 		return (1);
212 
213 	case ETHERTYPE_8021Q:
214 		printf("802.1Q ");
215 	case ETHERTYPE_QINQ:
216 		if (ethertype == ETHERTYPE_QINQ)
217 			printf("QinQ s");
218 		printf("vid %d pri %d%s",
219 		       ntohs(*(unsigned short*)p)&0xFFF,
220 		       ntohs(*(unsigned short*)p)>>13,
221 		       (ntohs(*(unsigned short*)p)&0x1000) ? " cfi " : " ");
222 		ethertype = ntohs(*(unsigned short*)(p+2));
223 		p += 4;
224 		length -= 4;
225 		caplen -= 4;
226 		if (ethertype > ETHERMTU)
227 			goto recurse;
228 
229 		extracted_ethertype = 0;
230 
231 		if (llc_print(p, length, caplen, p-18, p-12) == 0) {
232 			/* ether_type not known, print raw packet */
233 			if (!eflag)
234 				ether_print(p-18, length+4);
235 			if (extracted_ethertype) {
236 				printf("(LLC %s) ",
237 				etherproto_string(htons(extracted_ethertype)));
238 			}
239 			if (!xflag && !qflag)
240 				default_print(p-18, caplen+4);
241 		}
242 		return (1);
243 
244 #ifdef PPP
245 	case ETHERTYPE_PPPOEDISC:
246 	case ETHERTYPE_PPPOE:
247 		pppoe_if_print(ethertype, p, length, caplen);
248 		return (1);
249 #endif
250 
251 	case ETHERTYPE_FLOWCONTROL:
252 		ether_macctl(p, length);
253 		return (1);
254 
255 	case ETHERTYPE_MPLS:
256 	case ETHERTYPE_MPLS_MCAST:
257 		mpls_print(p, length);
258 		return (1);
259 
260 	case ETHERTYPE_LLDP:
261 		lldp_print(p, length);
262 		return (1);
263 
264 	case ETHERTYPE_SLOW:
265 		slow_print(p, length);
266 		return (1);
267 
268 	case ETHERTYPE_LAT:
269 	case ETHERTYPE_SCA:
270 	case ETHERTYPE_MOPRC:
271 	case ETHERTYPE_MOPDL:
272 		/* default_print for now */
273 	default:
274 		return (0);
275 	}
276 }
277 
278 void
279 ether_macctl(const u_char *p, u_int length)
280 {
281 	printf("MACCTL");
282 
283 	if (length < 2)
284 		goto trunc;
285 	if (EXTRACT_16BITS(p) == 0x0001) {
286 		u_int plen;
287 
288 		printf(" PAUSE");
289 
290 		length -= 2;
291 		p += 2;
292 		if (length < 2)
293 			goto trunc;
294 		plen = 512 * EXTRACT_16BITS(p);
295 		printf(" quanta %u", plen);
296 	} else {
297 		printf(" unknown-opcode(0x%04x)", EXTRACT_16BITS(p));
298 	}
299 	return;
300 
301 trunc:
302 	printf("[|MACCTL]");
303 }
304