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 #include <sys/cdefs.h> 38 #ifndef lint 39 __RCSID("$NetBSD: print-carp.c,v 1.5 2024/09/02 16:15:30 christos Exp $"); 40 #endif 41 42 /* \summary: Common Address Redundancy Protocol (CARP) printer */ 43 44 #include <config.h> 45 46 #include "netdissect-stdinc.h" 47 48 #include "netdissect.h" /* for checksum structure and functions */ 49 #include "extract.h" 50 51 void 52 carp_print(netdissect_options *ndo, const u_char *bp, u_int len, u_int ttl) 53 { 54 u_int version, type; 55 const char *type_s; 56 57 ndo->ndo_protocol = "carp"; 58 nd_print_protocol_caps(ndo); 59 version = (GET_U_1(bp) & 0xf0) >> 4; 60 type = GET_U_1(bp) & 0x0f; 61 if (type == 1) 62 type_s = "advertise"; 63 else 64 type_s = "unknown"; 65 ND_PRINT("v%u-%s %u: ", version, type_s, len); 66 if (ttl != 255) 67 ND_PRINT("[ttl=%u!] ", ttl); 68 if (version != 2 || type != 1) 69 return; 70 ND_PRINT("vhid=%u advbase=%u advskew=%u authlen=%u ", 71 GET_U_1(bp + 1), GET_U_1(bp + 5), GET_U_1(bp + 2), 72 GET_U_1(bp + 3)); 73 if (ndo->ndo_vflag) { 74 struct cksum_vec vec[1]; 75 vec[0].ptr = (const uint8_t *)bp; 76 vec[0].len = len; 77 if (ND_TTEST_LEN(bp, len) && in_cksum(vec, 1)) 78 ND_PRINT(" (bad carp cksum %x!)", 79 GET_BE_U_2(bp + 6)); 80 } 81 ND_PRINT("counter=%" PRIu64, GET_BE_U_8(bp + 8)); 82 } 83