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      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 #include <sys/cdefs.h>
     20 #ifndef lint
     21 __RCSID("$NetBSD: print-msdp.c,v 1.9 2026/03/19 00:05:13 christos Exp $");
     22 #endif
     23 
     24 /* \summary: Multicast Source Discovery Protocol (MSDP) printer */
     25 
     26 #include <config.h>
     27 
     28 #define ND_LONGJMP_FROM_TCHECK
     29 #include "netdissect-stdinc.h"
     30 
     31 #include "netdissect.h"
     32 #include "addrtoname.h"
     33 #include "extract.h"
     34 
     35 #define MSDP_TYPE_MAX	7
     36 
     37 void
     38 msdp_print(netdissect_options *ndo, const u_char *sp, u_int length)
     39 {
     40 	unsigned int type, len;
     41 
     42 	ndo->ndo_protocol = "msdp";
     43 	ND_PRINT(": ");
     44 	nd_print_protocol(ndo);
     45 	/* See if we think we're at the beginning of a compound packet */
     46 	type = GET_U_1(sp);
     47 	len = GET_BE_U_2(sp + 1);
     48 	if (len > 1500 || len < 3 || type == 0 || type > MSDP_TYPE_MAX)
     49 		goto trunc;	/* not really truncated, but still not decodable */
     50 	while (length != 0) {
     51 		unsigned int entry_count;
     52 
     53 		if (length < 3)
     54 			goto trunc;
     55 		type = GET_U_1(sp);
     56 		len = GET_BE_U_2(sp + 1);
     57 		if (len > 1400 || ndo->ndo_vflag)
     58 			ND_PRINT(" [len %u]", len);
     59 		if (len < 3)
     60 			goto trunc;
     61 		if (length < len)
     62 			goto trunc;
     63 		switch (type) {
     64 		case 1:	/* IPv4 Source-Active */
     65 		case 3: /* IPv4 Source-Active Response */
     66 			if (type == 1)
     67 				ND_PRINT(" SA");
     68 			else
     69 				ND_PRINT(" SA-Response");
     70 
     71 			/* Entry Count */
     72 			if (len < 4)
     73 				goto trunc;
     74 			entry_count = GET_U_1(sp + 3);
     75 			ND_PRINT(" %u entries", entry_count);
     76 
     77 			/* RP Address */
     78 			if (len < 8)
     79 				goto trunc;
     80 			/* XXX -print this based on ndo_vflag? */
     81 			ND_TCHECK_LEN(sp + 4, 4);
     82 
     83 			/* Entries */
     84 			ND_TCHECK_LEN(sp + 8, entry_count*12);
     85 
     86 			if (len > (8 + entry_count*12)) {
     87 				/* Encapsulated IP packet */
     88 				ND_PRINT(" [w/data]");
     89 				if (ndo->ndo_vflag > 1) {
     90 					ND_PRINT(" ");
     91 					ip_print(ndo, sp + (8 + entry_count*12),
     92 					    len - (8 + entry_count*12));
     93 				}
     94 			}
     95 			break;
     96 		case 2:
     97 			/* draft-ietf-msdp-spec-13 */
     98 			ND_PRINT(" SA-Request");
     99 
    100 			/* Reserved */
    101 			if (len < 4)
    102 				goto trunc;
    103 			ND_TCHECK_1(sp + 3);
    104 
    105 			/* Group Address */
    106 			if (len < 8)
    107 				goto trunc;
    108 			if (len != 8)
    109 				ND_PRINT("[len=%u] ", len);
    110 			ND_PRINT(" for %s", GET_IPADDR_STRING(sp + 4));
    111 			break;
    112 		case 4:
    113 			ND_PRINT(" Keepalive");
    114 			if (len != 3)
    115 				ND_PRINT("[len=%u] ", len);
    116 			break;
    117 		case 5:
    118 			ND_PRINT(" Notification");
    119 			break;
    120 		default:
    121 			ND_PRINT(" [type=%u len=%u]", type, len);
    122 			break;
    123 		}
    124 		ND_TCHECK_LEN(sp, len);
    125 		sp += len;
    126 		length -= len;
    127 	}
    128 	return;
    129 trunc:
    130 	nd_print_trunc(ndo);
    131 }
    132