xref: /freebsd/contrib/tcpdump/print-ether.c (revision e627b39baccd1ec9129690167cf5e6d860509655)
1 /*
2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996
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 #ifndef lint
22 static char rcsid[] =
23     "@(#) $Header: print-ether.c,v 1.42 96/07/23 14:17:23 leres Exp $ (LBL)";
24 #endif
25 
26 #include <sys/param.h>
27 #include <sys/time.h>
28 #include <sys/socket.h>
29 
30 #if __STDC__
31 struct mbuf;
32 struct rtentry;
33 #endif
34 #include <net/if.h>
35 
36 #include <netinet/in.h>
37 #include <netinet/if_ether.h>
38 #include <netinet/in_systm.h>
39 #include <netinet/ip.h>
40 #include <netinet/ip_var.h>
41 #include <netinet/udp.h>
42 #include <netinet/udp_var.h>
43 #include <netinet/tcp.h>
44 #include <netinet/tcpip.h>
45 
46 #include <stdio.h>
47 #include <pcap.h>
48 
49 #include "interface.h"
50 #include "addrtoname.h"
51 #include "ethertype.h"
52 
53 const u_char *packetp;
54 const u_char *snapend;
55 
56 static inline void
57 ether_print(register const u_char *bp, u_int length)
58 {
59 	register const struct ether_header *ep;
60 
61 	ep = (const struct ether_header *)bp;
62 	if (qflag)
63 		(void)printf("%s %s %d: ",
64 			     etheraddr_string(ESRC(ep)),
65 			     etheraddr_string(EDST(ep)),
66 			     length);
67 	else
68 		(void)printf("%s %s %s %d: ",
69 			     etheraddr_string(ESRC(ep)),
70 			     etheraddr_string(EDST(ep)),
71 			     etherproto_string(ep->ether_type),
72 			     length);
73 }
74 
75 /*
76  * This is the top level routine of the printer.  'p' is the points
77  * to the ether header of the packet, 'tvp' is the timestamp,
78  * 'length' is the length of the packet off the wire, and 'caplen'
79  * is the number of bytes actually captured.
80  */
81 void
82 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
83 {
84 	u_int caplen = h->caplen;
85 	u_int length = h->len;
86 	struct ether_header *ep;
87 	u_short ether_type;
88 	extern u_short extracted_ethertype;
89 
90 	ts_print(&h->ts);
91 
92 	if (caplen < sizeof(struct ether_header)) {
93 		printf("[|ether]");
94 		goto out;
95 	}
96 
97 	if (eflag)
98 		ether_print(p, length);
99 
100 	/*
101 	 * Some printers want to get back at the ethernet addresses,
102 	 * and/or check that they're not walking off the end of the packet.
103 	 * Rather than pass them all the way down, we set these globals.
104 	 */
105 	packetp = p;
106 	snapend = p + caplen;
107 
108 	length -= sizeof(struct ether_header);
109 	caplen -= sizeof(struct ether_header);
110 	ep = (struct ether_header *)p;
111 	p += sizeof(struct ether_header);
112 
113 	ether_type = ntohs(ep->ether_type);
114 
115 	/*
116 	 * Is it (gag) an 802.3 encapsulation?
117 	 */
118 	extracted_ethertype = 0;
119 	if (ether_type <= ETHERMTU) {
120 		/* Try to print the LLC-layer header & higher layers */
121 		if (llc_print(p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
122 			/* ether_type not known, print raw packet */
123 			if (!eflag)
124 				ether_print((u_char *)ep, length);
125 			if (extracted_ethertype) {
126 				printf("(LLC %s) ",
127 			       etherproto_string(htons(extracted_ethertype)));
128 			}
129 			if (!xflag && !qflag)
130 				default_print(p, caplen);
131 		}
132 	} else if (ether_encap_print(ether_type, p, length, caplen) == 0) {
133 		/* ether_type not known, print raw packet */
134 		if (!eflag)
135 			ether_print((u_char *)ep, length + sizeof(*ep));
136 		if (!xflag && !qflag)
137 			default_print(p, caplen);
138 	}
139 	if (xflag)
140 		default_print(p, caplen);
141  out:
142 	putchar('\n');
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  * Stuffs the ether type into a global for the benefit of lower layers
152  * that might want to know what it is.
153  */
154 
155 u_short	extracted_ethertype;
156 
157 int
158 ether_encap_print(u_short ethertype, const u_char *p,
159     u_int length, u_int caplen)
160 {
161 	extracted_ethertype = ethertype;
162 
163 	switch (ethertype) {
164 
165 	case ETHERTYPE_IP:
166 		ip_print(p, length);
167 		return (1);
168 
169 	case ETHERTYPE_ARP:
170 	case ETHERTYPE_REVARP:
171 		arp_print(p, length, caplen);
172 		return (1);
173 
174 	case ETHERTYPE_DN:
175 		decnet_print(p, length, caplen);
176 		return (1);
177 
178 	case ETHERTYPE_ATALK:
179 		if (vflag)
180 			fputs("et1 ", stdout);
181 		atalk_print(p, length);
182 		return (1);
183 
184 	case ETHERTYPE_AARP:
185 		aarp_print(p, length);
186 		return (1);
187 
188 	case ETHERTYPE_IPX:
189 		ipx_print(p, length);
190 		return (1);
191 
192 	case ETHERTYPE_LAT:
193 	case ETHERTYPE_SCA:
194 	case ETHERTYPE_MOPRC:
195 	case ETHERTYPE_MOPDL:
196 		/* default_print for now */
197 	default:
198 		return (0);
199 	}
200 }
201