The Tcpdump Group git mirrors - tcpdump/blob - print-vrrp.c

   1 /*
   2  * Copyright (c) 2000 William C. Fenner.
   3  *                All rights reserved.
   4  *
   5  * Kevin Steves <ks@hp.se> July 2000
   6  * Modified to:
   7  * - print version, type string and packet length
   8  * - print IP address count if > 1 (-v)
   9  * - verify checksum (-v)
  10  * - print authentication string (-v)
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that: (1) source code
  14  * distributions retain the above copyright notice and this paragraph
  15  * in its entirety, and (2) distributions including binary code include
  16  * the above copyright notice and this paragraph in its entirety in
  17  * the documentation or other materials provided with the distribution.
  18  * The name of William C. Fenner may not be used to endorse or
  19  * promote products derived from this software without specific prior
  20  * written permission.  THIS SOFTWARE IS PROVIDED ``AS IS'' AND
  21  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
  22  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  23  * FOR A PARTICULAR PURPOSE.
  24  */
  25
  26 /* \summary: Virtual Router Redundancy Protocol (VRRP) printer */
  27
  28 #include <config.h>
  29
  30 #include "netdissect-stdinc.h"
  31
  32 #include "netdissect.h"
  33 #include "extract.h"
  34 #include "addrtoname.h"
  35
  36 #include "ip.h"
  37 #include "ipproto.h"
  38 /*
  39  * RFC 2338 (VRRP v2):
  40  *
  41  *     0                   1                   2                   3
  42  *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  43  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  44  *    |Version| Type  | Virtual Rtr ID|   Priority    | Count IP Addrs|
  45  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  46  *    |   Auth Type   |   Adver Int   |          Checksum             |
  47  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  48  *    |                         IP Address (1)                        |
  49  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  50  *    |                            .                                  |
  51  *    |                            .                                  |
  52  *    |                            .                                  |
  53  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  54  *    |                         IP Address (n)                        |
  55  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  56  *    |                     Authentication Data (1)                   |
  57  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  58  *    |                     Authentication Data (2)                   |
  59  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  60  *
  61  *
  62  * RFC 5798 (VRRP v3):
  63  *
  64  *    0                   1                   2                   3
  65  *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  66  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  67  *    |                    IPv4 Fields or IPv6 Fields                 |
  68  *   ...                                                             ...
  69  *    |                                                               |
  70  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  71  *    |Version| Type  | Virtual Rtr ID|   Priority    |Count IPvX Addr|
  72  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  73  *    |(rsvd) |     Max Adver Int     |          Checksum             |
  74  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  75  *    |                                                               |
  76  *    +                                                               +
  77  *    |                       IPvX Address(es)                        |
  78  *    +                                                               +
  79  *    |                                                               |
  80  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  81  */
  82
  83 /* Type */
  84 #define VRRP_TYPE_ADVERTISEMENT 1
  85
  86 static const struct tok type2str[] = {
  87         { VRRP_TYPE_ADVERTISEMENT,      "Advertisement" },
  88         { 0,                            NULL            }
  89 };
  90
  91 /* Auth Type */
  92 #define VRRP_AUTH_NONE          0
  93 #define VRRP_AUTH_SIMPLE        1
  94 #define VRRP_AUTH_AH            2
  95
  96 static const struct tok auth2str[] = {
  97         { VRRP_AUTH_NONE,               "none"          },
  98         { VRRP_AUTH_SIMPLE,             "simple"        },
  99         { VRRP_AUTH_AH,                 "ah"            },
 100         { 0,                            NULL            }
 101 };
 102
 103 void
 104 vrrp_print(netdissect_options *ndo,
 105            const u_char *bp, u_int len,
 106            const u_char *bp2, int ttl,
 107            int ver)
 108 {
 109         int version, type, auth_type = VRRP_AUTH_NONE; /* keep compiler happy */
 110         const char *type_s;
 111
 112         ndo->ndo_protocol = "vrrp";
 113         nd_print_protocol_caps(ndo);
 114         version = (GET_U_1(bp) & 0xf0) >> 4;
 115         type = GET_U_1(bp) & 0x0f;
 116         type_s = tok2str(type2str, "unknown type (%u)", type);
 117         ND_PRINT("v%u, %s", version, type_s);
 118         if (ttl != 255)
 119                 ND_PRINT(", (ttl %u)", ttl);
 120         if (version < 2 || version > 3 || type != VRRP_TYPE_ADVERTISEMENT)
 121                 return;
 122         ND_PRINT(", vrid %u, prio %u", GET_U_1(bp + 1), GET_U_1(bp + 2));
 123
 124         if (version == 2) {
 125                 auth_type = GET_U_1(bp + 4);
 126                 ND_PRINT(", authtype %s", tok2str(auth2str, NULL, auth_type));
 127                 ND_PRINT(", intvl %us, length %u", GET_U_1(bp + 5), len);
 128         } else { /* version == 3 */
 129                 uint16_t intvl = (GET_U_1(bp + 4) & 0x0f) << 8 | GET_U_1(bp + 5);
 130                 ND_PRINT(", intvl %ucs, length %u", intvl, len);
 131         }
 132
 133         if (ndo->ndo_vflag) {
 134                 u_int naddrs = GET_U_1(bp + 3);
 135                 u_int i;
 136                 char c;
 137
 138                 if (version == 2 && ND_TTEST_LEN(bp, len)) {
 139                         struct cksum_vec vec[1];
 140
 141                         vec[0].ptr = bp;
 142                         vec[0].len = len;
 143                         if (in_cksum(vec, 1))
 144                                 ND_PRINT(", (bad vrrp cksum %x)",
 145                                         GET_BE_U_2(bp + 6));
 146                 }
 147
 148                 if (version == 3 && ND_TTEST_LEN(bp, len)) {
 149                         uint16_t cksum;
 150
 151                         if (ver == 4)
 152                                 cksum = nextproto4_cksum(ndo, (const struct ip *)bp2, bp,
 153                                         len, len, IPPROTO_VRRP);
 154                         else
 155                                 cksum = nextproto6_cksum(ndo, (const struct ip6_hdr *)bp2, bp,
 156                                         len, len, IPPROTO_VRRP);
 157                         if (cksum)
 158                                 ND_PRINT(", (bad vrrp cksum %x)",
 159                                         GET_BE_U_2(bp + 6));
 160                 }
 161
 162                 ND_PRINT(", addrs");
 163                 if (naddrs > 1)
 164                         ND_PRINT("(%u)", naddrs);
 165                 ND_PRINT(":");
 166                 c = ' ';
 167                 bp += 8;
 168                 for (i = 0; i < naddrs; i++) {
 169                         if (ver == 4) {
 170                                 ND_PRINT("%c%s", c, GET_IPADDR_STRING(bp));
 171                                 bp += 4;
 172                         } else {
 173                                 ND_PRINT("%c%s", c, GET_IP6ADDR_STRING(bp));
 174                                 bp += 16;
 175                         }
 176                         c = ',';
 177                 }
 178                 if (version == 2 && auth_type == VRRP_AUTH_SIMPLE) { /* simple text password */
 179                         ND_PRINT(" auth \"");
 180                         /*
 181                          * RFC 2338 Section 5.3.10: "If the configured authentication string
 182                          * is shorter than 8 bytes, the remaining space MUST be zero-filled.
 183                          */
 184                         nd_printjnp(ndo, bp, 8);
 185                         ND_PRINT("\"");
 186                 }
 187         }
 188 }