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 #include <config.h>
  33
  34 #include "netdissect-stdinc.h"
  35
  36 #include "netdissect.h"
  37 #include "addrtoname.h"
  38 #include "extract.h"
  39
  40 #include "ip6.h"
  41
  42 static int
  43 ip6_sopt_print(netdissect_options *ndo, const u_char *bp, int len)
  44 {
  45     int i;
  46     int optlen;
  47
  48     for (i = 0; i < len; i += optlen) {
  49         if (GET_U_1(bp + i) == IP6OPT_PAD1)
  50             optlen = 1;
  51         else {
  52             if (i + 1 < len)
  53                 optlen = GET_U_1(bp + i + 1) + 2;
  54             else
  55                 goto trunc;
  56         }
  57         if (i + optlen > len)
  58             goto trunc;
  59
  60         switch (GET_U_1(bp + i)) {
  61         case IP6OPT_PAD1:
  62             ND_PRINT(", pad1");
  63             break;
  64         case IP6OPT_PADN:
  65             if (len - i < IP6OPT_MINLEN) {
  66                 ND_PRINT(", padn: trunc");
  67                 goto trunc;
  68             }
  69             ND_PRINT(", padn");
  70             break;
  71         default:
  72             if (len - i < IP6OPT_MINLEN) {
  73                 ND_PRINT(", sopt_type %u: trunc)", GET_U_1(bp + i));
  74                 goto trunc;
  75             }
  76             ND_PRINT(", sopt_type 0x%02x: len=%u", GET_U_1(bp + i),
  77                      GET_U_1(bp + i + 1));
  78             break;
  79         }
  80     }
  81     return 0;
  82
  83 trunc:
  84     return -1;
  85 }
  86
  87 static int
  88 ip6_opt_process(netdissect_options *ndo, const u_char *bp, int len,
  89                 int *found_jumbop, uint32_t *payload_len)
  90 {
  91     int i;
  92     int optlen = 0;
  93     int found_jumbo = 0;
  94     uint32_t jumbolen = 0;
  95
  96     if (len == 0)
  97         return 0;
  98     for (i = 0; i < len; i += optlen) {
  99         if (GET_U_1(bp + i) == IP6OPT_PAD1)
 100             optlen = 1;
 101         else {
 102             if (i + 1 < len)
 103                 optlen = GET_U_1(bp + i + 1) + 2;
 104             else
 105                 goto trunc;
 106         }
 107         if (i + optlen > len)
 108             goto trunc;
 109
 110         switch (GET_U_1(bp + i)) {
 111         case IP6OPT_PAD1:
 112             if (ndo->ndo_vflag)
 113                 ND_PRINT("(pad1)");
 114             break;
 115         case IP6OPT_PADN:
 116             if (len - i < IP6OPT_MINLEN) {
 117                 ND_PRINT("(padn: trunc)");
 118                 goto trunc;
 119             }
 120             if (ndo->ndo_vflag)
 121                 ND_PRINT("(padn)");
 122             break;
 123         case IP6OPT_ROUTER_ALERT:
 124             if (len - i < IP6OPT_RTALERT_LEN) {
 125                 ND_PRINT("(rtalert: trunc)");
 126                 goto trunc;
 127             }
 128             if (GET_U_1(bp + i + 1) != IP6OPT_RTALERT_LEN - 2) {
 129                 ND_PRINT("(rtalert: invalid len %u)", GET_U_1(bp + i + 1));
 130                 goto trunc;
 131             }
 132             if (ndo->ndo_vflag)
 133                 ND_PRINT("(rtalert: 0x%04x) ", GET_BE_U_2(bp + i + 2));
 134             break;
 135         case IP6OPT_JUMBO:
 136             if (len - i < IP6OPT_JUMBO_LEN) {
 137                 ND_PRINT("(jumbo: trunc)");
 138                 goto trunc;
 139             }
 140             if (GET_U_1(bp + i + 1) != IP6OPT_JUMBO_LEN - 2) {
 141                 ND_PRINT("(jumbo: invalid len %u)", GET_U_1(bp + i + 1));
 142                 goto trunc;
 143             }
 144             jumbolen = GET_BE_U_4(bp + i + 2);
 145             if (found_jumbo) {
 146                 /* More than one Jumbo Payload option */
 147                 if (ndo->ndo_vflag)
 148                     ND_PRINT("(jumbo: %u - already seen) ", jumbolen);
 149             } else {
 150                 found_jumbo = 1;
 151                 if (payload_len == NULL) {
 152                     /* Not a hop-by-hop option - not valid */
 153                     if (ndo->ndo_vflag)
 154                         ND_PRINT("(jumbo: %u - not a hop-by-hop option) ", jumbolen);
 155                 } else if (*payload_len != 0) {
 156                     /* Payload length was non-zero - not valid */
 157                     if (ndo->ndo_vflag)
 158                         ND_PRINT("(jumbo: %u - payload len != 0) ", jumbolen);
 159                 } else {
 160                     /*
 161                      * This is a hop-by-hop option, and Payload length
 162                      * was zero in the IPv6 header.
 163                      */
 164                     if (jumbolen < 65536) {
 165                         /* Too short */
 166                         if (ndo->ndo_vflag)
 167                             ND_PRINT("(jumbo: %u - < 65536) ", jumbolen);
 168                     } else {
 169                         /* OK, this is valid */
 170                         *found_jumbop = 1;
 171                         *payload_len = jumbolen;
 172                         if (ndo->ndo_vflag)
 173                             ND_PRINT("(jumbo: %u) ", jumbolen);
 174                     }
 175                 }
 176             }
 177             break;
 178         case IP6OPT_HOME_ADDRESS:
 179             if (len - i < IP6OPT_HOMEADDR_MINLEN) {
 180                 ND_PRINT("(homeaddr: trunc)");
 181                 goto trunc;
 182             }
 183             if (GET_U_1(bp + i + 1) < IP6OPT_HOMEADDR_MINLEN - 2) {
 184                 ND_PRINT("(homeaddr: invalid len %u)", GET_U_1(bp + i + 1));
 185                 goto trunc;
 186             }
 187             if (ndo->ndo_vflag) {
 188                 ND_PRINT("(homeaddr: %s", GET_IP6ADDR_STRING(bp + i + 2));
 189                 if (GET_U_1(bp + i + 1) > IP6OPT_HOMEADDR_MINLEN - 2) {
 190                     if (ip6_sopt_print(ndo, bp + i + IP6OPT_HOMEADDR_MINLEN,
 191                                        (optlen - IP6OPT_HOMEADDR_MINLEN)) == -1)
 192                         goto trunc;
 193                 }
 194                 ND_PRINT(")");
 195             }
 196             break;
 197         default:
 198             if (len - i < IP6OPT_MINLEN) {
 199                 ND_PRINT("(type %u: trunc)", GET_U_1(bp + i));
 200                 goto trunc;
 201             }
 202             if (ndo->ndo_vflag)
 203                 ND_PRINT("(opt_type 0x%02x: len=%u)", GET_U_1(bp + i),
 204                          GET_U_1(bp + i + 1));
 205             break;
 206         }
 207     }
 208     if (ndo->ndo_vflag)
 209         ND_PRINT(" ");
 210     return 0;
 211
 212 trunc:
 213     return -1;
 214 }
 215
 216 int
 217 hbhopt_process(netdissect_options *ndo, const u_char *bp, int *found_jumbo,
 218                uint32_t *jumbolen)
 219 {
 220     const struct ip6_hbh *dp = (const struct ip6_hbh *)bp;
 221     u_int hbhlen = 0;
 222
 223     ndo->ndo_protocol = "hbh";
 224     hbhlen = (GET_U_1(dp->ip6h_len) + 1) << 3;
 225     ND_TCHECK_LEN(dp, hbhlen);
 226     nd_print_protocol_caps(ndo);
 227     ND_PRINT(" ");
 228     if (ip6_opt_process(ndo, (const u_char *)dp + sizeof(*dp),
 229                         hbhlen - sizeof(*dp), found_jumbo, jumbolen) == -1)
 230         goto trunc;
 231     return hbhlen;
 232
 233 trunc:
 234     nd_print_trunc(ndo);
 235     return -1;
 236 }
 237
 238 int
 239 dstopt_process(netdissect_options *ndo, const u_char *bp)
 240 {
 241     const struct ip6_dest *dp = (const struct ip6_dest *)bp;
 242     u_int dstoptlen = 0;
 243
 244     ndo->ndo_protocol = "dstopt";
 245     dstoptlen = (GET_U_1(dp->ip6d_len) + 1) << 3;
 246     ND_TCHECK_LEN(dp, dstoptlen);
 247     nd_print_protocol_caps(ndo);
 248     ND_PRINT(" ");
 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 }