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 #ifdef HAVE_CONFIG_H
  29 #include <config.h>
  30 #endif
  31
  32 #include "netdissect-stdinc.h"
  33
  34 #include "netdissect.h"
  35 #include "extract.h"
  36 #include "addrtoname.h"
  37
  38 #include "ip.h"
  39 #include "ipproto.h"
  40 /*
  41  * RFC 2338 (VRRP v2):
  42  *
  43  *     0                   1                   2                   3
  44  *     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
  45  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  46  *    |Version| Type  | Virtual Rtr ID|   Priority    | Count IP Addrs|
  47  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  48  *    |   Auth Type   |   Adver Int   |          Checksum             |
  49  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  50  *    |                         IP Address (1)                        |
  51  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  52  *    |                            .                                  |
  53  *    |                            .                                  |
  54  *    |                            .                                  |
  55  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  56  *    |                         IP Address (n)                        |
  57  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  58  *    |                     Authentication Data (1)                   |
  59  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  60  *    |                     Authentication Data (2)                   |
  61  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  62  *
  63  *
  64  * RFC 5798 (VRRP v3):
  65  *
  66  *    0                   1                   2                   3
  67  *    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
  68  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  69  *    |                    IPv4 Fields or IPv6 Fields                 |
  70  *   ...                                                             ...
  71  *    |                                                               |
  72  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  73  *    |Version| Type  | Virtual Rtr ID|   Priority    |Count IPvX Addr|
  74  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  75  *    |(rsvd) |     Max Adver Int     |          Checksum             |
  76  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  77  *    |                                                               |
  78  *    +                                                               +
  79  *    |                       IPvX Address(es)                        |
  80  *    +                                                               +
  81  *    |                                                               |
  82  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  83  */
  84
  85 /* Type */
  86 #define VRRP_TYPE_ADVERTISEMENT 1
  87
  88 static const struct tok type2str[] = {
  89         { VRRP_TYPE_ADVERTISEMENT,      "Advertisement" },
  90         { 0,                            NULL            }
  91 };
  92
  93 /* Auth Type */
  94 #define VRRP_AUTH_NONE          0
  95 #define VRRP_AUTH_SIMPLE        1
  96 #define VRRP_AUTH_AH            2
  97
  98 static const struct tok auth2str[] = {
  99         { VRRP_AUTH_NONE,               "none"          },
 100         { VRRP_AUTH_SIMPLE,             "simple"        },
 101         { VRRP_AUTH_AH,                 "ah"            },
 102         { 0,                            NULL            }
 103 };
 104
 105 void
 106 vrrp_print(netdissect_options *ndo,
 107            const u_char *bp, u_int len,
 108            const u_char *bp2, int ttl)
 109 {
 110         int version, type, auth_type = VRRP_AUTH_NONE; /* keep compiler happy */
 111         const char *type_s;
 112
 113         ndo->ndo_protocol = "vrrp";
 114         nd_print_protocol_caps(ndo);
 115         version = (GET_U_1(bp) & 0xf0) >> 4;
 116         type = GET_U_1(bp) & 0x0f;
 117         type_s = tok2str(type2str, "unknown type (%u)", type);
 118         ND_PRINT("v%u, %s", version, type_s);
 119         if (ttl != 255)
 120                 ND_PRINT(", (ttl %u)", ttl);
 121         if (version < 2 || version > 3 || type != VRRP_TYPE_ADVERTISEMENT)
 122                 return;
 123         ND_PRINT(", vrid %u, prio %u", GET_U_1(bp + 1), GET_U_1(bp + 2));
 124
 125         if (version == 2) {
 126                 auth_type = GET_U_1(bp + 4);
 127                 ND_PRINT(", authtype %s", tok2str(auth2str, NULL, auth_type));
 128                 ND_PRINT(", intvl %us, length %u", GET_U_1(bp + 5), len);
 129         } else { /* version == 3 */
 130                 uint16_t intvl = (GET_U_1(bp + 4) & 0x0f) << 8 | GET_U_1(bp + 5);
 131                 ND_PRINT(", intvl %ucs, length %u", intvl, len);
 132         }
 133
 134         if (ndo->ndo_vflag) {
 135                 u_int naddrs = GET_U_1(bp + 3);
 136                 u_int i;
 137                 char c;
 138
 139                 if (version == 2 && ND_TTEST_LEN(bp, len)) {
 140                         struct cksum_vec vec[1];
 141
 142                         vec[0].ptr = bp;
 143                         vec[0].len = len;
 144                         if (in_cksum(vec, 1))
 145                                 ND_PRINT(", (bad vrrp cksum %x)",
 146                                         GET_BE_U_2(bp + 6));
 147                 }
 148
 149                 if (version == 3 && ND_TTEST_LEN(bp, len)) {
 150                         uint16_t cksum = nextproto4_cksum(ndo, (const struct ip *)bp2, bp,
 151                                 len, len, IPPROTO_VRRP);
 152                         if (cksum)
 153                                 ND_PRINT(", (bad vrrp cksum %x)",
 154                                         GET_BE_U_2(bp + 6));
 155                 }
 156
 157                 ND_PRINT(", addrs");
 158                 if (naddrs > 1)
 159                         ND_PRINT("(%u)", naddrs);
 160                 ND_PRINT(":");
 161                 c = ' ';
 162                 bp += 8;
 163                 for (i = 0; i < naddrs; i++) {
 164                         ND_PRINT("%c%s", c, GET_IPADDR_STRING(bp));
 165                         c = ',';
 166                         bp += 4;
 167                 }
 168                 if (version == 2 && auth_type == VRRP_AUTH_SIMPLE) { /* simple text password */
 169                         ND_PRINT(" auth \"");
 170                         /*
 171                          * RFC 2338 Section 5.3.10: "If the configured authentication string
 172                          * is shorter than 8 bytes, the remaining space MUST be zero-filled.
 173                          */
 174                         nd_printjnp(ndo, bp, 8);
 175                         ND_PRINT("\"");
 176                 }
 177         }
 178 }