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

   1 /*
   2  * Copyright (C) 1999 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 #ifdef HAVE_CONFIG_H
  31 #include "config.h"
  32 #endif
  33
  34 #include <sys/param.h>
  35 #include <sys/time.h>
  36 #include <sys/types.h>
  37 #include <sys/socket.h>
  38
  39 #include <netinet/in.h>
  40 #include <netinet/in_systm.h>
  41 #include <netinet/ip.h>
  42 #include <netinet/ip_var.h>
  43 #include <netinet/udp.h>
  44 #include <netinet/udp_var.h>
  45
  46 #include <errno.h>
  47 #include <stdio.h>
  48
  49 #include "interface.h"
  50 #include "addrtoname.h"
  51
  52 struct bgp {
  53         u_int8_t bgp_marker[16];
  54         u_int16_t bgp_len;
  55         u_int8_t bgp_type;
  56 };
  57 #define BGP_SIZE                19      /* unaligned */
  58
  59 #define BGP_OPEN                1
  60 #define BGP_UPDATE              2
  61 #define BGP_NOTIFICATION        3
  62 #define BGP_KEEPALIVE           4
  63
  64 struct bgp_open {
  65         u_int8_t bgpo_marker[16];
  66         u_int16_t bgpo_len;
  67         u_int8_t bgpo_type;
  68         u_int8_t bgpo_version;
  69         u_int16_t bgpo_myas;
  70         u_int16_t bgpo_holdtime;
  71         u_int32_t bgpo_id;
  72         u_int8_t bgpo_optlen;
  73         /* options should follow */
  74 };
  75
  76 struct bgp_notification {
  77         u_int8_t bgpn_marker[16];
  78         u_int16_t bgpn_len;
  79         u_int8_t bgpn_type;
  80         u_int8_t bgpn_major;
  81         u_int8_t bgpn_minor;
  82         /* data should follow */
  83 };
  84
  85 struct bgp_attr {
  86         u_int8_t bgpa_flags;
  87         u_int8_t bgpa_type;
  88         union {
  89                 u_int8_t len;
  90                 u_int16_t elen;
  91         } bgpa_len;
  92 #define bgp_attr_len(p) \
  93         (((p)->bgpa_flags & 0x10) ? \
  94                 ntohs((p)->bgpa_len.elen) : (p)->bgpa_len.len)
  95 #define bgp_attr_off(p) \
  96         (((p)->bgpa_flags & 0x10) ? 4 : 3)
  97 };
  98
  99 #define BGPTYPE_ORIGIN                  1
 100 #define BGPTYPE_AS_PATH                 2
 101 #define BGPTYPE_NEXT_HOP                3
 102 #define BGPTYPE_MULTI_EXIT_DISC         4
 103 #define BGPTYPE_LOCAL_PREF              5
 104 #define BGPTYPE_ATOMIC_AGGREGATE        6
 105 #define BGPTYPE_AGGREGATOR              7
 106 #define BGPTYPE_MP_REACH_NLRI           14      /* RFC2283 */
 107 #define BGPTYPE_MP_UNREACH_NLRI         15      /* RFC2283 */
 108
 109
 110 static const char *bgptype[] = {
 111         NULL, "OPEN", "UPDATE", "NOTIFICATION", "KEEPALIVE",
 112 };
 113 #define bgp_type(x) num_or_str(bgptype, sizeof(bgptype)/sizeof(bgptype[0]), (x))
 114
 115 static const char *bgpnotify_major[] = {
 116         NULL, "Message Header Error",
 117         "OPEN Message Error", "UPDATE Message Error",
 118         "Hold Timer Expired", "Finite State Machine Error",
 119         "Cease",
 120 };
 121 #define bgp_notify_major(x) \
 122         num_or_str(bgpnotify_major, \
 123                 sizeof(bgpnotify_major)/sizeof(bgpnotify_major[0]), (x))
 124
 125 static const char *bgpnotify_minor_1[] = {
 126         NULL, "Connection Not Synchronized",
 127         "Bad Message Length", "Bad Message Type",
 128 };
 129
 130 static const char *bgpnotify_minor_2[] = {
 131         NULL, "Unsupported Version Number",
 132         "Bad Peer AS", "Bad BGP Identifier",
 133         "Unsupported Optional Parameter", "Authentication Failure",
 134         "Unacceptable Hold Time",
 135 };
 136
 137 static const char *bgpnotify_minor_3[] = {
 138         NULL, "Malformed Attribute List",
 139         "Unrecognized Well-known Attribute", "Missing Well-known Attribute",
 140         "Attribute Flags Error", "Attribute Length Error",
 141         "Invalid ORIGIN Attribute", "AS Routing Loop",
 142         "Invalid NEXT_HOP Attribute", "Optional Attribute Error",
 143         "Invalid Network Field", "Malformed AS_PATH",
 144 };
 145
 146 static const char **bgpnotify_minor[] = {
 147         NULL, bgpnotify_minor_1, bgpnotify_minor_2, bgpnotify_minor_3,
 148 };
 149 static const int bgpnotify_minor_siz[] = {
 150         0, sizeof(bgpnotify_minor_1)/sizeof(bgpnotify_minor_1[0]),
 151         sizeof(bgpnotify_minor_2)/sizeof(bgpnotify_minor_2[0]),
 152         sizeof(bgpnotify_minor_3)/sizeof(bgpnotify_minor_3[0]),
 153 };
 154
 155 static const char *bgpattr_origin[] = {
 156         "IGP", "EGP", "INCOMPLETE",
 157 };
 158 #define bgp_attr_origin(x) \
 159         num_or_str(bgpattr_origin, \
 160                 sizeof(bgpattr_origin)/sizeof(bgpattr_origin[0]), (x))
 161
 162 static const char *bgpattr_type[] = {
 163         NULL, "ORIGIN", "AS_PATH", "NEXT_HOP",
 164         "MULTI_EXIT_DISC", "LOCAL_PREF", "ATOMIC_AGGREGATE", "AGGREGATOR",
 165         NULL, NULL, NULL, NULL,
 166         NULL, NULL, "MP_REACH_NLRI", "MP_UNREACH_NLRI",
 167 };
 168 #define bgp_attr_type(x) \
 169         num_or_str(bgpattr_type, \
 170                 sizeof(bgpattr_type)/sizeof(bgpattr_type[0]), (x))
 171
 172 /* Subsequent address family identifier, RFC2283 section 7 */
 173 static const char *bgpattr_nlri_safi[] = {
 174     "Reserved", "Unicast", "Multicast", "Unicast+Multicast",
 175 };
 176 #define bgp_attr_nlri_safi(x) \
 177         num_or_str(bgpattr_nlri_safi, \
 178                 sizeof(bgpattr_nlri_safi)/sizeof(bgpattr_nlri_safi[0]), (x))
 179
 180 /* RFC1700 address family numbers */
 181 #define AFNUM_INET      1
 182 #define AFNUM_INET6     2
 183 #define AFNUM_NSAP      3
 184 #define AFNUM_HDLC      4
 185 #define AFNUM_BBN1822   5
 186 #define AFNUM_802       6
 187 #define AFNUM_E163      7
 188 #define AFNUM_E164      8
 189 #define AFNUM_F69       9
 190 #define AFNUM_X121      10
 191 #define AFNUM_IPX       11
 192 #define AFNUM_ATALK     12
 193 #define AFNUM_DECNET    13
 194 #define AFNUM_BANYAN    14
 195 #define AFNUM_E164NSAP  15
 196
 197 static const char *afnumber[] = {
 198         "Reserved", "IPv4", "IPv6", "NSAP", "HDLC",
 199         "BBN 1822", "802", "E.163", "E.164", "F.69",
 200         "X.121", "IPX", "Appletalk", "Decnet IV", "Banyan Vines",
 201         "E.164 with NSAP subaddress",
 202 };
 203 #define af_name(x) \
 204         (((x) == 65535) ? afnumber[0] : \
 205                 num_or_str(afnumber, \
 206                         sizeof(afnumber)/sizeof(afnumber[0]), (x)))
 207
 208
 209 static const char *
 210 num_or_str(const char **table, size_t siz, int value)
 211 {
 212         static char buf[20];
 213         if (value < 0 || siz <= value || table[value] == NULL) {
 214                 sprintf(buf, "#%d", value);
 215                 return buf;
 216         } else
 217                 return table[value];
 218 }
 219
 220 static const char *
 221 bgp_notify_minor(int major, int minor)
 222 {
 223         static const char **table;
 224         int siz;
 225         static char buf[20];
 226         const char *p;
 227
 228         if (0 <= major
 229          && major < sizeof(bgpnotify_minor)/sizeof(bgpnotify_minor[0])
 230          && bgpnotify_minor[major]) {
 231                 table = bgpnotify_minor[major];
 232                 siz = bgpnotify_minor_siz[major];
 233                 if (0 <= minor && minor < siz && table[minor])
 234                         p = table[minor];
 235                 else
 236                         p = NULL;
 237         } else
 238                 p = NULL;
 239         if (p == NULL) {
 240                 sprintf(buf, "#%d", minor);
 241                 return buf;
 242         } else
 243                 return p;
 244 }
 245
 246 static int
 247 decode_prefix4(const u_char *pd, char *buf, int buflen)
 248 {
 249         struct in_addr addr;
 250         int plen;
 251
 252         plen = pd[0];
 253         if (plen < 0 || 32 < plen)
 254                 return -1;
 255
 256         memset(&addr, 0, sizeof(addr));
 257         memcpy(&addr, &pd[1], (plen + 7) / 8);
 258         if (plen % 8) {
 259                 ((u_char *)&addr)[(plen + 7) / 8 - 1] &=
 260                         ((0xff00 >> (plen % 8)) & 0xff);
 261         }
 262         sprintf(buf, "%s/%d", getname((char *)&addr), plen);
 263         return 1 + (plen + 7) / 8;
 264 }
 265
 266 #ifdef INET6
 267 static int
 268 decode_prefix6(const u_char *pd, char *buf, int buflen)
 269 {
 270         struct in6_addr addr;
 271         int plen;
 272
 273         plen = pd[0];
 274         if (plen < 0 || 128 < plen)
 275                 return -1;
 276
 277         memset(&addr, 0, sizeof(addr));
 278         memcpy(&addr, &pd[1], (plen + 7) / 8);
 279         if (plen % 8) {
 280                 addr.s6_addr[(plen + 7) / 8 - 1] &=
 281                         ((0xff00 >> (plen % 8)) & 0xff);
 282         }
 283         sprintf(buf, "%s/%d", getname6((char *)&addr), plen);
 284         return 1 + (plen + 7) / 8;
 285 }
 286 #endif
 287
 288 static void
 289 bgp_attr_print(const struct bgp_attr *attr, const u_char *dat, int len)
 290 {
 291         int i;
 292         u_int16_t af;
 293         u_int8_t safi, snpa;
 294         int advance;
 295         int tlen;
 296         const char *s;
 297         const u_char *p;
 298         char buf[256];
 299
 300         p = dat;
 301
 302         switch (attr->bgpa_type) {
 303         case BGPTYPE_ORIGIN:
 304                 if (len != 1)
 305                         printf(" invalid len");
 306                 else
 307                         printf(" %s", bgp_attr_origin(p[0]));
 308                 break;
 309         case BGPTYPE_AS_PATH:
 310                 if (len % 2) {
 311                         printf(" invalid len");
 312                         break;
 313                 }
 314                 for (i = 0; i < len; i += 2)
 315                         printf(" %u", ntohs(*(u_int16_t *)&p[i]));
 316                 break;
 317         case BGPTYPE_NEXT_HOP:
 318                 if (len != 4)
 319                         printf(" invalid len");
 320                 else
 321                         printf(" %s", getname(p));
 322                 break;
 323         case BGPTYPE_MULTI_EXIT_DISC:
 324         case BGPTYPE_LOCAL_PREF:
 325                 if (len != 4)
 326                         printf(" invalid len");
 327                 else
 328                         printf(" %u", (u_int32_t)ntohl(*(u_int32_t *)p));
 329                 break;
 330         case BGPTYPE_ATOMIC_AGGREGATE:
 331                 if (len != 0)
 332                         printf(" invalid len");
 333                 break;
 334         case BGPTYPE_AGGREGATOR:
 335                 if (len != 6) {
 336                         printf(" invalid len");
 337                         break;
 338                 }
 339                 printf(" AS #%u, origin %s", ntohs(*(u_int16_t *)p),
 340                         getname(p + 2));
 341                 break;
 342         case BGPTYPE_MP_REACH_NLRI:
 343                 af = ntohs(*(u_int16_t *)p);
 344                 safi = p[2];
 345                 if (safi >= 128)
 346                         printf(" %s vendor specific,", af_name(af));
 347                 else {
 348                         printf(" %s %s,", af_name(af),
 349                                 bgp_attr_nlri_safi(safi));
 350                 }
 351                 p += 3;
 352
 353                 if (af == AFNUM_INET)
 354                         ;
 355 #ifdef INET6
 356                 else if (af == AFNUM_INET6)
 357                         ;
 358 #endif
 359                 else
 360                         break;
 361
 362                 tlen = p[0];
 363                 if (tlen) {
 364                         printf(" nexthop");
 365                         if (af == AFNUM_INET)
 366                                 advance = 4;
 367 #ifdef INET6
 368                         else if (af == AFNUM_INET6)
 369                                 advance = 16;
 370 #endif
 371
 372                         for (i = 0; i < tlen; i += advance) {
 373                                 if (af == AFNUM_INET)
 374                                         printf(" %s", getname(p + 1 + i));
 375 #ifdef INET6
 376                                 else if (af == AFNUM_INET6)
 377                                         printf(" %s", getname6(p + 1 + i));
 378 #endif
 379                         }
 380                         printf(",");
 381                 }
 382                 p += 1 + tlen;
 383
 384                 snpa = p[0];
 385                 p++;
 386                 if (snpa) {
 387                         printf(" %u snpa", snpa);
 388                         for (/*nothing*/; snpa > 0; snpa--) {
 389                                 printf("(%d bytes)", p[0]);
 390                                 p += p[0] + 1;
 391                         }
 392                         printf(",");
 393                 }
 394
 395                 printf(" NLRI");
 396                 while (len - (p - dat) > 0) {
 397                         if (af == AFNUM_INET)
 398                                 advance = decode_prefix4(p, buf, sizeof(buf));
 399 #ifdef INET6
 400                         else if (af == AFNUM_INET6)
 401                                 advance = decode_prefix6(p, buf, sizeof(buf));
 402 #endif
 403                         printf(" %s", buf);
 404
 405                         p += advance;
 406                 }
 407
 408                 break;
 409
 410         case BGPTYPE_MP_UNREACH_NLRI:
 411                 af = ntohs(*(u_int16_t *)p);
 412                 safi = p[2];
 413                 if (safi >= 128)
 414                         printf(" %s vendor specific,", af_name(af));
 415                 else {
 416                         printf(" %s %s,", af_name(af),
 417                                 bgp_attr_nlri_safi(safi));
 418                 }
 419                 p += 3;
 420
 421                 printf(" Withdraw");
 422                 while (len - (p - dat) > 0) {
 423                         if (af == AFNUM_INET)
 424                                 advance = decode_prefix4(p, buf, sizeof(buf));
 425 #ifdef INET6
 426                         else if (af == AFNUM_INET6)
 427                                 advance = decode_prefix6(p, buf, sizeof(buf));
 428 #endif
 429                         printf(" %s", buf);
 430
 431                         p += advance;
 432                 }
 433                 break;
 434         default:
 435                 break;
 436         }
 437 }
 438
 439 static void
 440 bgp_open_print(const u_char *dat, int length)
 441 {
 442         struct bgp_open bgpo;
 443         int hlen;
 444
 445         memcpy(&bgpo, dat, sizeof(bgpo));
 446         hlen = ntohs(bgpo.bgpo_len);
 447
 448         printf(": Version %d,", bgpo.bgpo_version);
 449         printf(" AS #%u,", ntohs(bgpo.bgpo_myas));
 450         printf(" Holdtime %u,", ntohs(bgpo.bgpo_holdtime));
 451         printf(" ID %s,", getname((char *)&bgpo.bgpo_id));
 452         printf(" Option length %u", bgpo.bgpo_optlen);
 453 }
 454
 455 static void
 456 bgp_update_print(const u_char *dat, int length)
 457 {
 458         struct bgp bgp;
 459         struct bgp_attr bgpa;
 460         int hlen;
 461         const u_char *p;
 462         int len;
 463         int i, j;
 464         int newline;
 465
 466         memcpy(&bgp, dat, sizeof(bgp));
 467         hlen = ntohs(bgp.bgp_len);
 468         p = dat + BGP_SIZE;     /*XXX*/
 469         printf(":");
 470
 471         /* Unfeasible routes */
 472         len = ntohs(*(u_int16_t *)p);
 473         if (len) {
 474                 printf(" (Withdrawn routes: %d bytes)", len);
 475         }
 476         p += 2 + len;
 477
 478         len = ntohs(*(u_int16_t *)p);
 479         if (len) {
 480                 /* do something more useful!*/
 481                 i = 2;
 482                 printf(" (Path attributes:");   /* ) */
 483                 newline = 0;
 484                 while (i < 2 + len) {
 485                         int alen, aoff;
 486
 487                         memcpy(&bgpa, &p[i], sizeof(bgpa));
 488                         alen = bgp_attr_len(&bgpa);
 489                         aoff = bgp_attr_off(&bgpa);
 490
 491                         if (vflag && newline)
 492                                 printf("\n\t\t");
 493                         else
 494                                 printf(" ");
 495                         printf("(");            /* ) */
 496                         printf("%s", bgp_attr_type(bgpa.bgpa_type));
 497                         if (bgpa.bgpa_flags) {
 498                                 printf("[%s%s%s%s]",
 499                                         bgpa.bgpa_flags & 0x80 ? "O" : "",
 500                                         bgpa.bgpa_flags & 0x40 ? "T" : "",
 501                                         bgpa.bgpa_flags & 0x20 ? "P" : "",
 502                                         bgpa.bgpa_flags & 0x00 ? "E" : "");
 503                         }
 504
 505                         bgp_attr_print(&bgpa, &p[i + aoff], alen);
 506                         newline = 1;
 507
 508 #if 0
 509             default:
 510                 proto_tree_add_text(subtree2, p - pd + i + aoff, alen,
 511                         "Unknown (%d bytes)", alen);
 512                 break;
 513             }
 514 #endif
 515
 516                         /* ( */
 517                         printf(")");
 518
 519                         i += aoff + alen;
 520                 }
 521
 522                 /* ( */
 523                 printf(")");
 524         }
 525         p += 2 + len;
 526
 527 }
 528
 529 static void
 530 bgp_notification_print(const u_char *dat, int length)
 531 {
 532         struct bgp_notification bgpn;
 533         int hlen;
 534
 535         memcpy(&bgpn, dat, sizeof(bgpn));
 536         hlen = ntohs(bgpn.bgpn_len);
 537
 538         printf(": error %s,", bgp_notify_major(bgpn.bgpn_major));
 539         printf(" subcode %s",
 540                 bgp_notify_minor(bgpn.bgpn_major, bgpn.bgpn_minor));
 541 }
 542
 543 static void
 544 bgp_header_print(const u_char *dat, int length)
 545 {
 546         struct bgp bgp;
 547
 548         memcpy(&bgp, dat, sizeof(bgp));
 549         printf("(%s", bgp_type(bgp.bgp_type));          /* ) */
 550
 551         switch (bgp.bgp_type) {
 552         case BGP_OPEN:
 553                 bgp_open_print(dat, length);
 554                 break;
 555         case BGP_UPDATE:
 556                 bgp_update_print(dat, length);
 557                 break;
 558         case BGP_NOTIFICATION:
 559                 bgp_notification_print(dat, length);
 560                 break;
 561         }
 562
 563         /* ( */
 564         printf(")");
 565 }
 566
 567 void
 568 bgp_print(const u_char *dat, int length)
 569 {
 570         const u_char *p;
 571         const u_char *ep;
 572         const u_char *start, *end;
 573         const u_char marker[] = {
 574                 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
 575                 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
 576         };
 577         struct bgp bgp;
 578         u_int16_t hlen;
 579         int newline;
 580
 581         ep = dat + length;
 582         if (snapend < dat + length)
 583                 ep = snapend;
 584
 585         printf(": BGP");
 586
 587         p = dat;
 588         newline = 0;
 589         start = p;
 590         while (p < snapend) {
 591                 if (!TTEST2(p[0], 1))
 592                         break;
 593                 if (p[0] != 0xff) {
 594                         p++;
 595                         continue;
 596                 }
 597
 598                 if (!TTEST2(p[0], sizeof(marker)))
 599                         break;
 600                 if (memcmp(p, marker, sizeof(marker)) != 0) {
 601                         p++;
 602                         continue;
 603                 }
 604
 605                 /* found BGP header */
 606                 TCHECK2(p[0], BGP_SIZE);        /*XXX*/
 607                 memcpy(&bgp, p, sizeof(bgp));
 608
 609                 if (start != p)
 610                         printf(" [|BGP]");
 611
 612                 hlen = ntohs(bgp.bgp_len);
 613                 if (vflag && newline)
 614                         printf("\n\t");
 615                 else
 616                         printf(" ");
 617                 if (TTEST2(p[0], hlen)) {
 618                         bgp_header_print(p, hlen);
 619                         newline = 1;
 620                         p += hlen;
 621                         start = p;
 622                 } else {
 623                         printf("[|BGP %s]", bgp_type(bgp.bgp_type));
 624                         break;
 625                 }
 626         }
 627
 628         return;
 629
 630 trunc:
 631         printf(" [|BGP]");
 632 }