]> The Tcpdump Group git mirrors - tcpdump/blob - print-cip.c
Clean up printing of LLC packets.
[tcpdump] / print-cip.c
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 #ifdef HAVE_CONFIG_H
24 #include "config.h"
25 #endif
26
27 #include <string.h>
28
29 #include <tcpdump-stdinc.h>
30
31 #include "interface.h"
32 #include "addrtoname.h"
33
34 #define RFC1483LLC_LEN 8
35
36 static const unsigned char rfcllc[] = {
37 0xaa, /* DSAP: non-ISO */
38 0xaa, /* SSAP: non-ISO */
39 0x03, /* Ctrl: Unnumbered Information Command PDU */
40 0x00, /* OUI: EtherType */
41 0x00,
42 0x00 };
43
44 static inline void
45 cip_print(netdissect_options *ndo, int length)
46 {
47 /*
48 * There is no MAC-layer header, so just print the length.
49 */
50 ND_PRINT((ndo, "%d: ", length));
51 }
52
53 /*
54 * This is the top level routine of the printer. 'p' points
55 * to the LLC/SNAP or raw header of the packet, 'h->ts' is the timestamp,
56 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
57 * is the number of bytes actually captured.
58 */
59 u_int
60 cip_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
61 {
62 u_int caplen = h->caplen;
63 u_int length = h->len;
64
65 if (memcmp(rfcllc, p, sizeof(rfcllc))==0 && caplen < RFC1483LLC_LEN) {
66 ND_PRINT((ndo, "[|cip]"));
67 return (0);
68 }
69
70 if (ndo->ndo_eflag)
71 cip_print(ndo, length);
72
73 if (memcmp(rfcllc, p, sizeof(rfcllc)) == 0) {
74 /*
75 * LLC header is present. Try to print it & higher layers.
76 */
77 if (llc_print(ndo, p, length, caplen, NULL, NULL) == 0) {
78 if (!ndo->ndo_suppress_default_print)
79 ND_DEFAULTPRINT(p, caplen);
80 }
81 } else {
82 /*
83 * LLC header is absent; treat it as just IP.
84 */
85 ip_print(ndo, p, length);
86 }
87
88 return (0);
89 }
90
91
92 /*
93 * Local Variables:
94 * c-style: whitesmith
95 * c-basic-offset: 8
96 * End:
97 */