xref: /freebsd/contrib/tcpdump/print-cip.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
1 /*
2  * Marko Kiiskila carnil@cs.tut.fi
3  *
4  * Tampere University of Technology - Telecommunications Laboratory
5  *
6  * Permission to use, copy, modify and distribute this
7  * software and its documentation is hereby granted,
8  * provided that both the copyright notice and this
9  * permission notice appear in all copies of the software,
10  * derivative works or modified versions, and any portions
11  * thereof, that both notices appear in supporting
12  * documentation, and that the use of this software is
13  * acknowledged in any publications resulting from using
14  * the software.
15  *
16  * TUT ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
17  * CONDITION AND DISCLAIMS ANY LIABILITY OF ANY KIND FOR
18  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS
19  * SOFTWARE.
20  *
21  */
22 
23 #ifndef lint
24 static const char rcsid[] _U_ =
25     "@(#) $Header: /tcpdump/master/tcpdump/print-cip.c,v 1.25.2.1 2005/07/07 01:24:34 guy Exp $ (LBL)";
26 #endif
27 
28 #ifdef HAVE_CONFIG_H
29 #include "config.h"
30 #endif
31 
32 #include <string.h>
33 
34 #include <tcpdump-stdinc.h>
35 
36 #include <stdio.h>
37 #include <pcap.h>
38 
39 #include "interface.h"
40 #include "addrtoname.h"
41 #include "ethertype.h"
42 #include "ether.h"
43 
44 #define RFC1483LLC_LEN	8
45 
46 static unsigned char rfcllc[] = {
47 	0xaa,	/* DSAP: non-ISO */
48 	0xaa,	/* SSAP: non-ISO */
49 	0x03,	/* Ctrl: Unnumbered Information Command PDU */
50 	0x00,	/* OUI: EtherType */
51 	0x00,
52 	0x00 };
53 
54 static inline void
55 cip_print(int length)
56 {
57 	/*
58 	 * There is no MAC-layer header, so just print the length.
59 	 */
60 	printf("%d: ", length);
61 }
62 
63 /*
64  * This is the top level routine of the printer.  'p' points
65  * to the LLC/SNAP or raw header of the packet, 'h->ts' is the timestamp,
66  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
67  * is the number of bytes actually captured.
68  */
69 u_int
70 cip_if_print(const struct pcap_pkthdr *h, const u_char *p)
71 {
72 	u_int caplen = h->caplen;
73 	u_int length = h->len;
74 	u_short extracted_ethertype;
75 
76 	if (memcmp(rfcllc, p, sizeof(rfcllc))==0 && caplen < RFC1483LLC_LEN) {
77 		printf("[|cip]");
78 		return (0);
79 	}
80 
81 	if (eflag)
82 		cip_print(length);
83 
84 	if (memcmp(rfcllc, p, sizeof(rfcllc)) == 0) {
85 		/*
86 		 * LLC header is present.  Try to print it & higher layers.
87 		 */
88 		if (llc_print(p, length, caplen, NULL, NULL,
89 		    &extracted_ethertype) == 0) {
90 			/* ether_type not known, print raw packet */
91 			if (!eflag)
92 				cip_print(length);
93 			if (extracted_ethertype) {
94 				printf("(LLC %s) ",
95 			       etherproto_string(htons(extracted_ethertype)));
96 			}
97 			if (!suppress_default_print)
98 				default_print(p, caplen);
99 		}
100 	} else {
101 		/*
102 		 * LLC header is absent; treat it as just IP.
103 		 */
104 		ip_print(gndo, p, length);
105 	}
106 
107 	return (0);
108 }
109 
110 
111 /*
112  * Local Variables:
113  * c-style: whitesmith
114  * c-basic-offset: 8
115  * End:
116  */
117