1 /* $OpenBSD: print-carp.c,v 1.6 2009/10/27 23:59:55 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 2000 William C. Fenner. 5 * All rights reserved. 6 * 7 * Kevin Steves <ks@hp.se> July 2000 8 * Modified to: 9 * - print version, type string and packet length 10 * - print IP address count if > 1 (-v) 11 * - verify checksum (-v) 12 * - print authentication string (-v) 13 * 14 * Copyright (c) 2011 Advanced Computing Technologies 15 * George V. Neille-Neil 16 * 17 * Modified to: 18 * - work correctly with CARP 19 * - compile into the latest tcpdump 20 * - print out the counter 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that: (1) source code 24 * distributions retain the above copyright notice and this paragraph 25 * in its entirety, and (2) distributions including binary code include 26 * the above copyright notice and this paragraph in its entirety in 27 * the documentation or other materials provided with the distribution. 28 * The name of William C. Fenner may not be used to endorse or 29 * promote products derived from this software without specific prior 30 * written permission. THIS SOFTWARE IS PROVIDED ``AS IS'' AND 31 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT 32 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 33 * FOR A PARTICULAR PURPOSE. 34 * 35 */ 36 37 /* \summary: Common Address Redundancy Protocol (CARP) printer */ 38 39 #ifdef HAVE_CONFIG_H 40 #include "config.h" 41 #endif 42 43 #include <netdissect-stdinc.h> 44 45 #include "netdissect.h" /* for checksum structure and functions */ 46 #include "extract.h" 47 48 void 49 carp_print(netdissect_options *ndo, register const u_char *bp, register u_int len, int ttl) 50 { 51 int version, type; 52 const char *type_s; 53 54 ND_TCHECK(bp[0]); 55 version = (bp[0] & 0xf0) >> 4; 56 type = bp[0] & 0x0f; 57 if (type == 1) 58 type_s = "advertise"; 59 else 60 type_s = "unknown"; 61 ND_PRINT((ndo, "CARPv%d-%s %d: ", version, type_s, len)); 62 if (ttl != 255) 63 ND_PRINT((ndo, "[ttl=%d!] ", ttl)); 64 if (version != 2 || type != 1) 65 return; 66 ND_TCHECK(bp[2]); 67 ND_TCHECK(bp[5]); 68 ND_PRINT((ndo, "vhid=%d advbase=%d advskew=%d authlen=%d ", 69 bp[1], bp[5], bp[2], bp[3])); 70 if (ndo->ndo_vflag) { 71 struct cksum_vec vec[1]; 72 vec[0].ptr = (const uint8_t *)bp; 73 vec[0].len = len; 74 if (ND_TTEST2(bp[0], len) && in_cksum(vec, 1)) 75 ND_PRINT((ndo, " (bad carp cksum %x!)", 76 EXTRACT_16BITS(&bp[6]))); 77 } 78 ND_PRINT((ndo, "counter=%" PRIu64, EXTRACT_64BITS(&bp[8]))); 79 80 return; 81 trunc: 82 ND_PRINT((ndo, "[|carp]")); 83 } 84