1 /*
2 * Copyright (c) 2001 William C. Fenner.
3 * 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
7 * distributions retain the above copyright notice and this paragraph
8 * in its entirety, and (2) distributions including binary code include
9 * the above copyright notice and this paragraph in its entirety in
10 * the documentation or other materials provided with the distribution.
11 * The name of William C. Fenner may not be used to endorse or
12 * promote products derived from this software without specific prior
13 * written permission. THIS SOFTWARE IS PROVIDED ``AS IS'' AND
14 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
15 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
16 * FOR A PARTICULAR PURPOSE.
17 */
18
19 /* \summary: Multicast Source Discovery Protocol (MSDP) printer */
20
21 #include <config.h>
22
23 #include "netdissect-stdinc.h"
24
25 #include "netdissect.h"
26 #include "addrtoname.h"
27 #include "extract.h"
28
29 #define MSDP_TYPE_MAX 7
30
31 void
msdp_print(netdissect_options * ndo,const u_char * sp,u_int length)32 msdp_print(netdissect_options *ndo, const u_char *sp, u_int length)
33 {
34 unsigned int type, len;
35
36 ndo->ndo_protocol = "msdp";
37 ND_PRINT(": ");
38 nd_print_protocol(ndo);
39 /* See if we think we're at the beginning of a compound packet */
40 type = GET_U_1(sp);
41 len = GET_BE_U_2(sp + 1);
42 if (len > 1500 || len < 3 || type == 0 || type > MSDP_TYPE_MAX)
43 goto trunc; /* not really truncated, but still not decodable */
44 while (length != 0) {
45 type = GET_U_1(sp);
46 len = GET_BE_U_2(sp + 1);
47 if (len > 1400 || ndo->ndo_vflag)
48 ND_PRINT(" [len %u]", len);
49 if (len < 3)
50 goto trunc;
51 if (length < len)
52 goto trunc;
53 sp += 3;
54 length -= 3;
55 switch (type) {
56 case 1: /* IPv4 Source-Active */
57 case 3: /* IPv4 Source-Active Response */
58 if (type == 1)
59 ND_PRINT(" SA");
60 else
61 ND_PRINT(" SA-Response");
62 ND_PRINT(" %u entries", GET_U_1(sp));
63 if ((u_int)((GET_U_1(sp) * 12) + 8) < len) {
64 ND_PRINT(" [w/data]");
65 if (ndo->ndo_vflag > 1) {
66 ND_PRINT(" ");
67 ip_print(ndo, sp +
68 GET_U_1(sp) * 12 + 8 - 3,
69 len - (GET_U_1(sp) * 12 + 8));
70 }
71 }
72 break;
73 case 2:
74 ND_PRINT(" SA-Request");
75 ND_PRINT(" for %s", GET_IPADDR_STRING(sp + 1));
76 break;
77 case 4:
78 ND_PRINT(" Keepalive");
79 if (len != 3)
80 ND_PRINT("[len=%u] ", len);
81 break;
82 case 5:
83 ND_PRINT(" Notification");
84 break;
85 default:
86 ND_PRINT(" [type=%u len=%u]", type, len);
87 break;
88 }
89 sp += (len - 3);
90 length -= (len - 3);
91 }
92 return;
93 trunc:
94 nd_print_trunc(ndo);
95 }
96