The Tcpdump Group git mirrors - tcpdump/blob - print-ip6opts.c

   1 /*
   2  * Copyright (C) 1998 WIDE Project.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the project nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 /* \summary: IPv6 header option printer */
  31
  32 #ifdef HAVE_CONFIG_H
  33 #include <config.h>
  34 #endif
  35
  36 #include "netdissect-stdinc.h"
  37
  38 #include "netdissect.h"
  39 #include "addrtoname.h"
  40 #include "extract.h"
  41
  42 #include "ip6.h"
  43
  44 static int
  45 ip6_sopt_print(netdissect_options *ndo, const u_char *bp, int len)
  46 {
  47     int i;
  48     int optlen;
  49
  50     for (i = 0; i < len; i += optlen) {
  51         if (GET_U_1(bp + i) == IP6OPT_PAD1)
  52             optlen = 1;
  53         else {
  54             if (i + 1 < len)
  55                 optlen = GET_U_1(bp + i + 1) + 2;
  56             else
  57                 goto trunc;
  58         }
  59         if (i + optlen > len)
  60             goto trunc;
  61
  62         switch (GET_U_1(bp + i)) {
  63         case IP6OPT_PAD1:
  64             ND_PRINT(", pad1");
  65             break;
  66         case IP6OPT_PADN:
  67             if (len - i < IP6OPT_MINLEN) {
  68                 ND_PRINT(", padn: trunc");
  69                 goto trunc;
  70             }
  71             ND_PRINT(", padn");
  72             break;
  73         default:
  74             if (len - i < IP6OPT_MINLEN) {
  75                 ND_PRINT(", sopt_type %u: trunc)", GET_U_1(bp + i));
  76                 goto trunc;
  77             }
  78             ND_PRINT(", sopt_type 0x%02x: len=%u", GET_U_1(bp + i),
  79                      GET_U_1(bp + i + 1));
  80             break;
  81         }
  82     }
  83     return 0;
  84
  85 trunc:
  86     return -1;
  87 }
  88
  89 static int
  90 ip6_opt_process(netdissect_options *ndo, const u_char *bp, int len,
  91                 int *found_jumbop, uint32_t *payload_len)
  92 {
  93     int i;
  94     int optlen = 0;
  95     int found_jumbo = 0;
  96     uint32_t jumbolen = 0;
  97
  98     if (len == 0)
  99         return 0;
 100     for (i = 0; i < len; i += optlen) {
 101         if (GET_U_1(bp + i) == IP6OPT_PAD1)
 102             optlen = 1;
 103         else {
 104             if (i + 1 < len)
 105                 optlen = GET_U_1(bp + i + 1) + 2;
 106             else
 107                 goto trunc;
 108         }
 109         if (i + optlen > len)
 110             goto trunc;
 111
 112         switch (GET_U_1(bp + i)) {
 113         case IP6OPT_PAD1:
 114             if (ndo->ndo_vflag)
 115                 ND_PRINT("(pad1)");
 116             break;
 117         case IP6OPT_PADN:
 118             if (len - i < IP6OPT_MINLEN) {
 119                 ND_PRINT("(padn: trunc)");
 120                 goto trunc;
 121             }
 122             if (ndo->ndo_vflag)
 123                 ND_PRINT("(padn)");
 124             break;
 125         case IP6OPT_ROUTER_ALERT:
 126             if (len - i < IP6OPT_RTALERT_LEN) {
 127                 ND_PRINT("(rtalert: trunc)");
 128                 goto trunc;
 129             }
 130             if (GET_U_1(bp + i + 1) != IP6OPT_RTALERT_LEN - 2) {
 131                 ND_PRINT("(rtalert: invalid len %u)", GET_U_1(bp + i + 1));
 132                 goto trunc;
 133             }
 134             if (ndo->ndo_vflag)
 135                 ND_PRINT("(rtalert: 0x%04x) ", GET_BE_U_2(bp + i + 2));
 136             break;
 137         case IP6OPT_JUMBO:
 138             if (len - i < IP6OPT_JUMBO_LEN) {
 139                 ND_PRINT("(jumbo: trunc)");
 140                 goto trunc;
 141             }
 142             if (GET_U_1(bp + i + 1) != IP6OPT_JUMBO_LEN - 2) {
 143                 ND_PRINT("(jumbo: invalid len %u)", GET_U_1(bp + i + 1));
 144                 goto trunc;
 145             }
 146             jumbolen = GET_BE_U_4(bp + i + 2);
 147             if (found_jumbo) {
 148                 /* More than one Jumbo Payload option */
 149                 if (ndo->ndo_vflag)
 150                     ND_PRINT("(jumbo: %u - already seen) ", jumbolen);
 151             } else {
 152                 found_jumbo = 1;
 153                 if (payload_len == NULL) {
 154                     /* Not a hop-by-hop option - not valid */
 155                     if (ndo->ndo_vflag)
 156                         ND_PRINT("(jumbo: %u - not a hop-by-hop option) ", jumbolen);
 157                 } else if (*payload_len != 0) {
 158                     /* Payload length was non-zero - not valid */
 159                     if (ndo->ndo_vflag)
 160                         ND_PRINT("(jumbo: %u - payload len != 0) ", jumbolen);
 161                 } else {
 162                     /*
 163                      * This is a hop-by-hop option, and Payload length
 164                      * was zero in the IPv6 header.
 165                      */
 166                     if (jumbolen < 65536) {
 167                         /* Too short */
 168                         if (ndo->ndo_vflag)
 169                             ND_PRINT("(jumbo: %u - < 65536) ", jumbolen);
 170                     } else {
 171                         /* OK, this is valid */
 172                         *found_jumbop = 1;
 173                         *payload_len = jumbolen;
 174                         if (ndo->ndo_vflag)
 175                             ND_PRINT("(jumbo: %u) ", jumbolen);
 176                     }
 177                 }
 178             }
 179             break;
 180         case IP6OPT_HOME_ADDRESS:
 181             if (len - i < IP6OPT_HOMEADDR_MINLEN) {
 182                 ND_PRINT("(homeaddr: trunc)");
 183                 goto trunc;
 184             }
 185             if (GET_U_1(bp + i + 1) < IP6OPT_HOMEADDR_MINLEN - 2) {
 186                 ND_PRINT("(homeaddr: invalid len %u)", GET_U_1(bp + i + 1));
 187                 goto trunc;
 188             }
 189             if (ndo->ndo_vflag) {
 190                 ND_PRINT("(homeaddr: %s", GET_IP6ADDR_STRING(bp + i + 2));
 191                 if (GET_U_1(bp + i + 1) > IP6OPT_HOMEADDR_MINLEN - 2) {
 192                     if (ip6_sopt_print(ndo, bp + i + IP6OPT_HOMEADDR_MINLEN,
 193                                        (optlen - IP6OPT_HOMEADDR_MINLEN)) == -1)
 194                         goto trunc;
 195                 }
 196                 ND_PRINT(")");
 197             }
 198             break;
 199         default:
 200             if (len - i < IP6OPT_MINLEN) {
 201                 ND_PRINT("(type %u: trunc)", GET_U_1(bp + i));
 202                 goto trunc;
 203             }
 204             if (ndo->ndo_vflag)
 205                 ND_PRINT("(opt_type 0x%02x: len=%u)", GET_U_1(bp + i),
 206                          GET_U_1(bp + i + 1));
 207             break;
 208         }
 209     }
 210     if (ndo->ndo_vflag)
 211         ND_PRINT(" ");
 212     return 0;
 213
 214 trunc:
 215     return -1;
 216 }
 217
 218 int
 219 hbhopt_process(netdissect_options *ndo, const u_char *bp, int *found_jumbo,
 220                uint32_t *jumbolen)
 221 {
 222     const struct ip6_hbh *dp = (const struct ip6_hbh *)bp;
 223     u_int hbhlen = 0;
 224
 225     ndo->ndo_protocol = "hbhopt";
 226     hbhlen = (GET_U_1(dp->ip6h_len) + 1) << 3;
 227     ND_TCHECK_LEN(dp, hbhlen);
 228     ND_PRINT("HBH ");
 229     if (ip6_opt_process(ndo, (const u_char *)dp + sizeof(*dp),
 230                         hbhlen - sizeof(*dp), found_jumbo, jumbolen) == -1)
 231         goto trunc;
 232     return hbhlen;
 233
 234 trunc:
 235     nd_print_trunc(ndo);
 236     return -1;
 237 }
 238
 239 int
 240 dstopt_process(netdissect_options *ndo, const u_char *bp)
 241 {
 242     const struct ip6_dest *dp = (const struct ip6_dest *)bp;
 243     u_int dstoptlen = 0;
 244
 245     ndo->ndo_protocol = "dstopt";
 246     dstoptlen = (GET_U_1(dp->ip6d_len) + 1) << 3;
 247     ND_TCHECK_LEN(dp, dstoptlen);
 248     ND_PRINT("DSTOPT ");
 249     if (ndo->ndo_vflag) {
 250         /*
 251          * The Jumbo Payload option is a hop-by-hop option; we don't
 252          * honor Jumbo Payload destination options, reporting them
 253          * as invalid.
 254          */
 255         if (ip6_opt_process(ndo, (const u_char *)dp + sizeof(*dp),
 256                             dstoptlen - sizeof(*dp), NULL, NULL) == -1)
 257             goto trunc;
 258     }
 259
 260     return dstoptlen;
 261
 262 trunc:
 263     nd_print_trunc(ndo);
 264     return -1;
 265 }