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      1 /*
      2  * Copyright (c) 2007-2011 Grgoire Henry, Juliusz Chroboczek
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  * 3. Neither the name of the project nor the names of its contributors
     13  *    may be used to endorse or promote products derived from this software
     14  *    without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #ifdef HAVE_CONFIG_H
     30 #include "config.h"
     31 #endif
     32 
     33 #include <tcpdump-stdinc.h>
     34 
     35 #include <stdio.h>
     36 #include <string.h>
     37 
     38 #include "addrtoname.h"
     39 #include "interface.h"
     40 #include "extract.h"
     41 
     42 static void babel_print_v2(const u_char *cp, u_int length);
     43 
     44 void
     45 babel_print(const u_char *cp, u_int length) {
     46     printf("babel");
     47 
     48     TCHECK2(*cp, 4);
     49 
     50     if(cp[0] != 42) {
     51         printf(" malformed header");
     52         return;
     53     } else {
     54         printf(" %d", cp[1]);
     55     }
     56 
     57     switch(cp[1]) {
     58     case 2:
     59         babel_print_v2(cp,length);
     60         break;
     61     default:
     62         printf(" unknown version");
     63         break;
     64     }
     65 
     66     return;
     67 
     68  trunc:
     69     printf(" [|babel]");
     70     return;
     71 }
     72 
     73 /* TLVs */
     74 #define MESSAGE_PAD1 0
     75 #define MESSAGE_PADN 1
     76 #define MESSAGE_ACK_REQ 2
     77 #define MESSAGE_ACK 3
     78 #define MESSAGE_HELLO 4
     79 #define MESSAGE_IHU 5
     80 #define MESSAGE_ROUTER_ID 6
     81 #define MESSAGE_NH 7
     82 #define MESSAGE_UPDATE 8
     83 #define MESSAGE_REQUEST 9
     84 #define MESSAGE_MH_REQUEST 10
     85 #define MESSAGE_TSPC 11
     86 #define MESSAGE_HMAC 12
     87 
     88 /* sub-TLVs */
     89 #define MESSAGE_SUB_PAD1 0
     90 #define MESSAGE_SUB_PADN 1
     91 #define MESSAGE_SUB_DIVERSITY 2
     92 
     93 /* Diversity sub-TLV channel codes */
     94 static const struct tok diversity_str[] = {
     95     { 0,   "reserved" },
     96     { 255, "all"      },
     97     { 0, NULL }
     98 };
     99 
    100 static const char *
    101 format_id(const u_char *id)
    102 {
    103     static char buf[25];
    104     snprintf(buf, 25, "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x",
    105              id[0], id[1], id[2], id[3], id[4], id[5], id[6], id[7]);
    106     buf[24] = '\0';
    107     return buf;
    108 }
    109 
    110 static const unsigned char v4prefix[16] =
    111     {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
    112 
    113 static const char *
    114 format_prefix(const u_char *prefix, unsigned char plen)
    115 {
    116     static char buf[50];
    117     if(plen >= 96 && memcmp(prefix, v4prefix, 12) == 0)
    118         snprintf(buf, 50, "%s/%u", ipaddr_string(prefix + 12), plen - 96);
    119     else
    120 #ifdef INET6
    121         snprintf(buf, 50, "%s/%u", ip6addr_string(prefix), plen);
    122 #else
    123         snprintf(buf, 50, "IPv6 addresses not supported");
    124 #endif
    125     buf[49] = '\0';
    126     return buf;
    127 }
    128 
    129 static const char *
    130 format_address(const u_char *prefix)
    131 {
    132     if(memcmp(prefix, v4prefix, 12) == 0)
    133         return ipaddr_string(prefix + 12);
    134     else
    135 #ifdef INET6
    136         return ip6addr_string(prefix);
    137 #else
    138         return "IPv6 addresses not supported";
    139 #endif
    140 }
    141 
    142 static const char *
    143 format_interval(const u_int16_t i)
    144 {
    145     static char buf[sizeof("0000.0s")];
    146 
    147     if (i == 0)
    148         return "0.0s (bogus)";
    149     snprintf(buf, sizeof(buf), "%u.%us", i / 10, i % 10);
    150     return buf;
    151 }
    152 
    153 static const char *
    154 format_interval_update(const u_int16_t i)
    155 {
    156     return i == 0xFFFF ? "infinity" : format_interval(i);
    157 }
    158 
    159 /* Return number of octets consumed from the input buffer (not the prefix length
    160  * in bytes), or -1 for encoding error. */
    161 static int
    162 network_prefix(int ae, int plen, unsigned int omitted,
    163                const unsigned char *p, const unsigned char *dp,
    164                unsigned int len, unsigned char *p_r)
    165 {
    166     unsigned pb;
    167     unsigned char prefix[16];
    168     int consumed = 0;
    169 
    170     if(plen >= 0)
    171         pb = (plen + 7) / 8;
    172     else if(ae == 1)
    173         pb = 4;
    174     else
    175         pb = 16;
    176 
    177     if(pb > 16)
    178         return -1;
    179 
    180     memset(prefix, 0, 16);
    181 
    182     switch(ae) {
    183     case 0: break;
    184     case 1:
    185         if(omitted > 4 || pb > 4 || (pb > omitted && len < pb - omitted))
    186             return -1;
    187         memcpy(prefix, v4prefix, 12);
    188         if(omitted) {
    189             if (dp == NULL) return -1;
    190             memcpy(prefix, dp, 12 + omitted);
    191         }
    192         if(pb > omitted) {
    193             memcpy(prefix + 12 + omitted, p, pb - omitted);
    194             consumed = pb - omitted;
    195         }
    196         break;
    197     case 2:
    198         if(omitted > 16 || (pb > omitted && len < pb - omitted))
    199             return -1;
    200         if(omitted) {
    201             if (dp == NULL) return -1;
    202             memcpy(prefix, dp, omitted);
    203         }
    204         if(pb > omitted) {
    205             memcpy(prefix + omitted, p, pb - omitted);
    206             consumed = pb - omitted;
    207         }
    208         break;
    209     case 3:
    210         if(pb > 8 && len < pb - 8) return -1;
    211         prefix[0] = 0xfe;
    212         prefix[1] = 0x80;
    213         if(pb > 8) {
    214             memcpy(prefix + 8, p, pb - 8);
    215             consumed = pb - 8;
    216         }
    217         break;
    218     default:
    219         return -1;
    220     }
    221 
    222     memcpy(p_r, prefix, 16);
    223     return consumed;
    224 }
    225 
    226 static int
    227 network_address(int ae, const unsigned char *a, unsigned int len,
    228                 unsigned char *a_r)
    229 {
    230     return network_prefix(ae, -1, 0, a, NULL, len, a_r);
    231 }
    232 
    233 /*
    234  * Sub-TLVs consume the "extra data" of Babel TLVs (see Section 4.3 of RFC6126),
    235  * their encoding is similar to the encoding of TLVs, but the type namespace is
    236  * different:
    237  *
    238  * o Type 0 stands for Pad1 sub-TLV with the same encoding as the Pad1 TLV.
    239  * o Type 1 stands for PadN sub-TLV with the same encoding as the PadN TLV.
    240  * o Type 2 stands for Diversity sub-TLV, which propagates diversity routing
    241  *   data. Its body is a variable-length sequence of 8-bit unsigned integers,
    242  *   each representing per-hop number of interferring radio channel for the
    243  *   prefix. Channel 0 is invalid and must not be used in the sub-TLV, channel
    244  *   255 interferes with any other channel.
    245  *
    246  * Sub-TLV types 0 and 1 are valid for any TLV type, whether sub-TLV type 2 is
    247  * only valid for TLV type 8 (Update). Note that within an Update TLV a missing
    248  * Diversity sub-TLV is not the same as a Diversity sub-TLV with an empty body.
    249  * The former would mean a lack of any claims about the interference, and the
    250  * latter would state that interference is definitely absent. */
    251 static void
    252 subtlvs_print(const u_char *cp, const u_char *ep, const uint8_t tlv_type) {
    253     uint8_t subtype, sublen;
    254     const char *sep;
    255 
    256     while (cp < ep) {
    257         subtype = *cp++;
    258         if(subtype == MESSAGE_SUB_PAD1) {
    259             printf(" sub-pad1");
    260             continue;
    261         }
    262         if(cp == ep)
    263             goto corrupt;
    264         sublen = *cp++;
    265         if(cp + sublen > ep)
    266             goto corrupt;
    267 
    268         switch(subtype) {
    269         case MESSAGE_SUB_PADN:
    270             printf(" sub-padn");
    271             cp += sublen;
    272             break;
    273         case MESSAGE_SUB_DIVERSITY:
    274             printf(" sub-diversity");
    275             if (sublen == 0) {
    276                 printf(" empty");
    277                 break;
    278             }
    279             sep = " ";
    280             while(sublen--) {
    281                 printf("%s%s", sep, tok2str(diversity_str, "%u", *cp++));
    282                 sep = "-";
    283             }
    284             if(tlv_type != MESSAGE_UPDATE)
    285                 printf(" (bogus)");
    286             break;
    287         default:
    288             printf(" sub-unknown-0x%02x", subtype);
    289             cp += sublen;
    290         } /* switch */
    291     } /* while */
    292     return;
    293 
    294  corrupt:
    295     printf(" (corrupt)");
    296 }
    297 
    298 #define ICHECK(i, l) \
    299 	if ((i) + (l) > bodylen || (i) + (l) > length) goto corrupt;
    300 
    301 static void
    302 babel_print_v2(const u_char *cp, u_int length) {
    303     u_int i;
    304     u_short bodylen;
    305     u_char v4_prefix[16] =
    306         {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
    307     u_char v6_prefix[16] = {0};
    308 
    309     TCHECK2(*cp, 4);
    310     if (length < 4)
    311         goto corrupt;
    312     bodylen = EXTRACT_16BITS(cp + 2);
    313     printf(" (%u)", bodylen);
    314 
    315     /* Process the TLVs in the body */
    316     i = 0;
    317     while(i < bodylen) {
    318         const u_char *message;
    319         u_int type, len;
    320 
    321         message = cp + 4 + i;
    322 
    323         TCHECK2(*message, 1);
    324         if((type = message[0]) == MESSAGE_PAD1) {
    325             printf(vflag ? "\n\tPad 1" : " pad1");
    326             i += 1;
    327             continue;
    328         }
    329 
    330         TCHECK2(*message, 2);
    331         ICHECK(i, 2);
    332         len = message[1];
    333 
    334         TCHECK2(*message, 2 + len);
    335         ICHECK(i, 2 + len);
    336 
    337         switch(type) {
    338         case MESSAGE_PADN: {
    339             if(!vflag)
    340                 printf(" padN");
    341             else
    342                 printf("\n\tPad %d", len + 2);
    343         }
    344             break;
    345 
    346         case MESSAGE_ACK_REQ: {
    347             u_short nonce, interval;
    348             if(!vflag)
    349                 printf(" ack-req");
    350             else {
    351                 printf("\n\tAcknowledgment Request ");
    352                 if(len < 6) goto corrupt;
    353                 nonce = EXTRACT_16BITS(message + 4);
    354                 interval = EXTRACT_16BITS(message + 6);
    355                 printf("%04x %s", nonce, format_interval(interval));
    356             }
    357         }
    358             break;
    359 
    360         case MESSAGE_ACK: {
    361             u_short nonce;
    362             if(!vflag)
    363                 printf(" ack");
    364             else {
    365                 printf("\n\tAcknowledgment ");
    366                 if(len < 2) goto corrupt;
    367                 nonce = EXTRACT_16BITS(message + 2);
    368                 printf("%04x", nonce);
    369             }
    370         }
    371             break;
    372 
    373         case MESSAGE_HELLO:  {
    374             u_short seqno, interval;
    375             if(!vflag)
    376                 printf(" hello");
    377             else {
    378                 printf("\n\tHello ");
    379                 if(len < 6) goto corrupt;
    380                 seqno = EXTRACT_16BITS(message + 4);
    381                 interval = EXTRACT_16BITS(message + 6);
    382                 printf("seqno %u interval %s", seqno, format_interval(interval));
    383             }
    384         }
    385             break;
    386 
    387         case MESSAGE_IHU: {
    388             unsigned short txcost, interval;
    389             if(!vflag)
    390                 printf(" ihu");
    391             else {
    392                 u_char address[16];
    393                 int rc;
    394                 printf("\n\tIHU ");
    395                 if(len < 6) goto corrupt;
    396                 txcost = EXTRACT_16BITS(message + 4);
    397                 interval = EXTRACT_16BITS(message + 6);
    398                 rc = network_address(message[2], message + 8, len - 6, address);
    399                 if(rc < 0) { printf("[|babel]"); break; }
    400                 printf("%s txcost %u interval %s",
    401                        format_address(address), txcost, format_interval(interval));
    402             }
    403         }
    404             break;
    405 
    406         case MESSAGE_ROUTER_ID: {
    407             if(!vflag)
    408                 printf(" router-id");
    409             else {
    410                 printf("\n\tRouter Id");
    411                 if(len < 10) goto corrupt;
    412                 printf(" %s", format_id(message + 4));
    413             }
    414         }
    415             break;
    416 
    417         case MESSAGE_NH: {
    418             if(!vflag)
    419                 printf(" nh");
    420             else {
    421                 int rc;
    422                 u_char nh[16];
    423                 printf("\n\tNext Hop");
    424                 if(len < 2) goto corrupt;
    425                 rc = network_address(message[2], message + 4, len - 2, nh);
    426                 if(rc < 0) goto corrupt;
    427                 printf(" %s", format_address(nh));
    428             }
    429         }
    430             break;
    431 
    432         case MESSAGE_UPDATE: {
    433             if(!vflag) {
    434                 printf(" update");
    435                 if(len < 1)
    436                     printf("/truncated");
    437                 else
    438                     printf("%s%s%s",
    439                            (message[3] & 0x80) ? "/prefix": "",
    440                            (message[3] & 0x40) ? "/id" : "",
    441                            (message[3] & 0x3f) ? "/unknown" : "");
    442             } else {
    443                 u_short interval, seqno, metric;
    444                 u_char plen;
    445                 int rc;
    446                 u_char prefix[16];
    447                 printf("\n\tUpdate");
    448                 if(len < 10) goto corrupt;
    449                 plen = message[4] + (message[2] == 1 ? 96 : 0);
    450                 rc = network_prefix(message[2], message[4], message[5],
    451                                     message + 12,
    452                                     message[2] == 1 ? v4_prefix : v6_prefix,
    453                                     len - 10, prefix);
    454                 if(rc < 0) goto corrupt;
    455                 interval = EXTRACT_16BITS(message + 6);
    456                 seqno = EXTRACT_16BITS(message + 8);
    457                 metric = EXTRACT_16BITS(message + 10);
    458                 printf("%s%s%s %s metric %u seqno %u interval %s",
    459                        (message[3] & 0x80) ? "/prefix": "",
    460                        (message[3] & 0x40) ? "/id" : "",
    461                        (message[3] & 0x3f) ? "/unknown" : "",
    462                        format_prefix(prefix, plen),
    463                        metric, seqno, format_interval_update(interval));
    464                 if(message[3] & 0x80) {
    465                     if(message[2] == 1)
    466                         memcpy(v4_prefix, prefix, 16);
    467                     else
    468                         memcpy(v6_prefix, prefix, 16);
    469                 }
    470                 /* extra data? */
    471                 if((u_int)rc < len - 10)
    472                     subtlvs_print(message + 12 + rc, message + 2 + len, type);
    473             }
    474         }
    475             break;
    476 
    477         case MESSAGE_REQUEST: {
    478             if(!vflag)
    479                 printf(" request");
    480             else {
    481                 int rc;
    482                 u_char prefix[16], plen;
    483                 printf("\n\tRequest ");
    484                 if(len < 2) goto corrupt;
    485                 plen = message[3] + (message[2] == 1 ? 96 : 0);
    486                 rc = network_prefix(message[2], message[3], 0,
    487                                     message + 4, NULL, len - 2, prefix);
    488                 if(rc < 0) goto corrupt;
    489                 plen = message[3] + (message[2] == 1 ? 96 : 0);
    490                 printf("for %s",
    491                        message[2] == 0 ? "any" : format_prefix(prefix, plen));
    492             }
    493         }
    494             break;
    495 
    496         case MESSAGE_MH_REQUEST : {
    497             if(!vflag)
    498                 printf(" mh-request");
    499             else {
    500                 int rc;
    501                 u_short seqno;
    502                 u_char prefix[16], plen;
    503                 printf("\n\tMH-Request ");
    504                 if(len < 14) goto corrupt;
    505                 seqno = EXTRACT_16BITS(message + 4);
    506                 rc = network_prefix(message[2], message[3], 0,
    507                                     message + 16, NULL, len - 14, prefix);
    508                 if(rc < 0) goto corrupt;
    509                 plen = message[3] + (message[2] == 1 ? 96 : 0);
    510                 printf("(%u hops) for %s seqno %u id %s",
    511                        message[6], format_prefix(prefix, plen),
    512                        seqno, format_id(message + 8));
    513             }
    514         }
    515             break;
    516         case MESSAGE_TSPC :
    517             if(!vflag)
    518                 printf(" tspc");
    519             else {
    520                 printf("\n\tTS/PC ");
    521                 if(len < 6) goto corrupt;
    522                 printf("timestamp %u packetcounter %u", EXTRACT_32BITS (message + 4),
    523                        EXTRACT_16BITS(message + 2));
    524             }
    525             break;
    526         case MESSAGE_HMAC : {
    527             if(!vflag)
    528                 printf(" hmac");
    529             else {
    530                 unsigned j;
    531                 printf("\n\tHMAC ");
    532                 if(len < 18) goto corrupt;
    533                 printf("key-id %u digest-%u ", EXTRACT_16BITS(message + 2), len - 2);
    534                 for (j = 0; j < len - 2; j++)
    535                     printf ("%02X", message[4 + j]);
    536             }
    537         }
    538             break;
    539         default:
    540             if(!vflag)
    541                 printf(" unknown");
    542             else
    543                 printf("\n\tUnknown message type %d", type);
    544         }
    545         i += len + 2;
    546     }
    547     return;
    548 
    549  trunc:
    550     printf(" [|babel]");
    551     return;
    552 
    553  corrupt:
    554     printf(" (corrupt)");
    555     return;
    556 }
    557