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

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21
  22 /* \summary: Linux cooked sockets capture printer */
  23
  24 #include <config.h>
  25
  26 #ifdef __linux__
  27 #include <net/if.h>
  28 #endif
  29
  30 #include "netdissect-stdinc.h"
  31
  32 #define ND_LONGJMP_FROM_TCHECK
  33 #include "netdissect.h"
  34 #include "addrtoname.h"
  35 #include "ethertype.h"
  36 #include "extract.h"
  37
  38 /*
  39  * For captures on Linux cooked sockets, we construct a fake header
  40  * that includes:
  41  *
  42  *      a 2-byte "packet type" which is one of:
  43  *
  44  *              LINUX_SLL_HOST          packet was sent to us
  45  *              LINUX_SLL_BROADCAST     packet was broadcast
  46  *              LINUX_SLL_MULTICAST     packet was multicast
  47  *              LINUX_SLL_OTHERHOST     packet was sent to somebody else
  48  *              LINUX_SLL_OUTGOING      packet was sent *by* us;
  49  *
  50  *      a 2-byte Ethernet protocol field;
  51  *
  52  *      a 2-byte link-layer type;
  53  *
  54  *      a 2-byte link-layer address length;
  55  *
  56  *      an 8-byte source link-layer address, whose actual length is
  57  *      specified by the previous value.
  58  *
  59  * All fields except for the link-layer address are in network byte order.
  60  *
  61  * DO NOT change the layout of this structure, or change any of the
  62  * LINUX_SLL_ values below.  If you must change the link-layer header
  63  * for a "cooked" Linux capture, introduce a new DLT_ type (ask
  64  * "tcpdump-workers@lists.tcpdump.org" for one, so that you don't give it
  65  * a value that collides with a value already being used), and use the
  66  * new header in captures of that type, so that programs that can
  67  * handle DLT_LINUX_SLL captures will continue to handle them correctly
  68  * without any change, and so that capture files with different headers
  69  * can be told apart and programs that read them can dissect the
  70  * packets in them.
  71  *
  72  * This structure, and the #defines below, must be the same in the
  73  * libpcap and tcpdump versions of "sll.h".
  74  */
  75
  76 /*
  77  * A DLT_LINUX_SLL fake link-layer header.
  78  */
  79 #define SLL_HDR_LEN     16              /* total header length */
  80 #define SLL_ADDRLEN     8               /* length of address field */
  81
  82 struct sll_header {
  83         nd_uint16_t     sll_pkttype;    /* packet type */
  84         nd_uint16_t     sll_hatype;     /* link-layer address type */
  85         nd_uint16_t     sll_halen;      /* link-layer address length */
  86         nd_byte         sll_addr[SLL_ADDRLEN];  /* link-layer address */
  87         nd_uint16_t     sll_protocol;   /* protocol */
  88 };
  89
  90 /*
  91  * A DLT_LINUX_SLL2 fake link-layer header.
  92  */
  93 #define SLL2_HDR_LEN    20              /* total header length */
  94
  95 struct sll2_header {
  96         nd_uint16_t     sll2_protocol;          /* protocol */
  97         nd_uint16_t     sll2_reserved_mbz;      /* reserved - must be zero */
  98         nd_uint32_t     sll2_if_index;          /* 1-based interface index */
  99         nd_uint16_t     sll2_hatype;            /* link-layer address type */
 100         nd_uint8_t      sll2_pkttype;           /* packet type */
 101         nd_uint8_t      sll2_halen;             /* link-layer address length */
 102         nd_byte         sll2_addr[SLL_ADDRLEN]; /* link-layer address */
 103 };
 104
 105 /*
 106  * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the
 107  * PACKET_ values on Linux, but are defined here so that they're
 108  * available even on systems other than Linux, and so that they
 109  * don't change even if the PACKET_ values change.
 110  */
 111 #define LINUX_SLL_HOST          0
 112 #define LINUX_SLL_BROADCAST     1
 113 #define LINUX_SLL_MULTICAST     2
 114 #define LINUX_SLL_OTHERHOST     3
 115 #define LINUX_SLL_OUTGOING      4
 116
 117 /*
 118  * The LINUX_SLL_ values for "sll_protocol"; these correspond to the
 119  * ETH_P_ values on Linux, but are defined here so that they're
 120  * available even on systems other than Linux.  We assume, for now,
 121  * that the ETH_P_ values won't change in Linux; if they do, then:
 122  *
 123  *      if we don't translate them in "pcap-linux.c", capture files
 124  *      won't necessarily be readable if captured on a system that
 125  *      defines ETH_P_ values that don't match these values;
 126  *
 127  *      if we do translate them in "pcap-linux.c", that makes life
 128  *      unpleasant for the BPF code generator, as the values you test
 129  *      for in the kernel aren't the values that you test for when
 130  *      reading a capture file, so the fixup code run on BPF programs
 131  *      handed to the kernel ends up having to do more work.
 132  *
 133  * Add other values here as necessary, for handling packet types that
 134  * might show up on non-Ethernet, non-802.x networks.  (Not all the ones
 135  * in the Linux "if_ether.h" will, I suspect, actually show up in
 136  * captures.)
 137  */
 138 #define LINUX_SLL_P_802_3       0x0001  /* Novell 802.3 frames without 802.2 LLC header */
 139 #define LINUX_SLL_P_802_2       0x0004  /* 802.2 frames (not D/I/X Ethernet) */
 140
 141 static const struct tok sll_pkttype_values[] = {
 142     { LINUX_SLL_HOST, "In" },
 143     { LINUX_SLL_BROADCAST, "B" },
 144     { LINUX_SLL_MULTICAST, "M" },
 145     { LINUX_SLL_OTHERHOST, "P" },
 146     { LINUX_SLL_OUTGOING, "Out" },
 147     { 0, NULL}
 148 };
 149
 150 static void
 151 sll_print(netdissect_options *ndo, const struct sll_header *sllp, u_int length)
 152 {
 153         u_short ether_type;
 154
 155         ndo->ndo_protocol = "sll";
 156         ND_PRINT("%3s ",
 157                  tok2str(sll_pkttype_values,"?",GET_BE_U_2(sllp->sll_pkttype)));
 158
 159         /*
 160          * XXX - check the link-layer address type value?
 161          * For now, we just assume 6 means Ethernet.
 162          * XXX - print others as strings of hex?
 163          */
 164         if (GET_BE_U_2(sllp->sll_halen) == MAC48_LEN)
 165                 ND_PRINT("%s ", GET_MAC48_STRING(sllp->sll_addr));
 166
 167         if (!ndo->ndo_qflag) {
 168                 ether_type = GET_BE_U_2(sllp->sll_protocol);
 169
 170                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 171                         /*
 172                          * Not an Ethernet type; what type is it?
 173                          */
 174                         switch (ether_type) {
 175
 176                         case LINUX_SLL_P_802_3:
 177                                 /*
 178                                  * Ethernet_802.3 IPX frame.
 179                                  */
 180                                 ND_PRINT("802.3");
 181                                 break;
 182
 183                         case LINUX_SLL_P_802_2:
 184                                 /*
 185                                  * 802.2.
 186                                  */
 187                                 ND_PRINT("802.2");
 188                                 break;
 189
 190                         default:
 191                                 /*
 192                                  * What is it?
 193                                  */
 194                                 ND_PRINT("ethertype Unknown (0x%04x)",
 195                                     ether_type);
 196                                 break;
 197                         }
 198                 } else {
 199                         ND_PRINT("ethertype %s (0x%04x)",
 200                             tok2str(ethertype_values, "Unknown", ether_type),
 201                             ether_type);
 202                 }
 203                 ND_PRINT(", length %u: ", length);
 204         }
 205 }
 206
 207 /*
 208  * This is the top level routine of the printer.  'p' points to the
 209  * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp,
 210  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
 211  * is the number of bytes actually captured.
 212  */
 213 void
 214 sll_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
 215 {
 216         u_int caplen = h->caplen;
 217         u_int length = h->len;
 218         const struct sll_header *sllp;
 219         u_short hatype;
 220         u_short ether_type;
 221         int llc_hdrlen;
 222         u_int hdrlen;
 223
 224         ndo->ndo_protocol = "sll";
 225         ND_TCHECK_LEN(p, SLL_HDR_LEN);
 226
 227         sllp = (const struct sll_header *)p;
 228
 229         if (ndo->ndo_eflag)
 230                 sll_print(ndo, sllp, length);
 231
 232         /*
 233          * Go past the cooked-mode header.
 234          */
 235         length -= SLL_HDR_LEN;
 236         caplen -= SLL_HDR_LEN;
 237         p += SLL_HDR_LEN;
 238         hdrlen = SLL_HDR_LEN;
 239
 240         hatype = GET_BE_U_2(sllp->sll_hatype);
 241         switch (hatype) {
 242
 243         case 803:
 244                 /*
 245                  * This is an packet with a radiotap header;
 246                  * just dissect the payload as such.
 247                  */
 248                 ndo->ndo_ll_hdr_len += SLL_HDR_LEN;
 249                 ndo->ndo_ll_hdr_len += ieee802_11_radio_print(ndo, p, length, caplen);
 250                 return;
 251         }
 252         ether_type = GET_BE_U_2(sllp->sll_protocol);
 253
 254 recurse:
 255         /*
 256          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 257          * packet type?
 258          */
 259         if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 260                 /*
 261                  * Yes - what type is it?
 262                  */
 263                 switch (ether_type) {
 264
 265                 case LINUX_SLL_P_802_3:
 266                         /*
 267                          * Ethernet_802.3 IPX frame.
 268                          */
 269                         ipx_print(ndo, p, length);
 270                         break;
 271
 272                 case LINUX_SLL_P_802_2:
 273                         /*
 274                          * 802.2.
 275                          * Try to print the LLC-layer header & higher layers.
 276                          */
 277                         llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
 278                         if (llc_hdrlen < 0)
 279                                 goto unknown;   /* unknown LLC type */
 280                         hdrlen += llc_hdrlen;
 281                         break;
 282
 283                 default:
 284                         /*FALLTHROUGH*/
 285
 286                 unknown:
 287                         /* packet type not known, print raw packet */
 288                         if (!ndo->ndo_suppress_default_print)
 289                                 ND_DEFAULTPRINT(p, caplen);
 290                         break;
 291                 }
 292         } else if (ether_type == ETHERTYPE_8021Q) {
 293                 /*
 294                  * Print VLAN information, and then go back and process
 295                  * the enclosed type field.
 296                  */
 297                 if (caplen < 4) {
 298                         ndo->ndo_protocol = "vlan";
 299                         nd_print_trunc(ndo);
 300                         ndo->ndo_ll_hdr_len += hdrlen + caplen;
 301                         return;
 302                 }
 303                 if (ndo->ndo_eflag) {
 304                         uint16_t tag = GET_BE_U_2(p);
 305
 306                         ND_PRINT("%s, ", ieee8021q_tci_string(tag));
 307                 }
 308
 309                 ether_type = GET_BE_U_2(p + 2);
 310                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL)
 311                         ether_type = LINUX_SLL_P_802_2;
 312                 if (!ndo->ndo_qflag) {
 313                         ND_PRINT("ethertype %s, ",
 314                             tok2str(ethertype_values, "Unknown", ether_type));
 315                 }
 316                 p += 4;
 317                 length -= 4;
 318                 caplen -= 4;
 319                 hdrlen += 4;
 320                 goto recurse;
 321         } else {
 322                 if (ethertype_print(ndo, ether_type, p, length, caplen, NULL, NULL) == 0) {
 323                         /* ether_type not known, print raw packet */
 324                         if (!ndo->ndo_eflag)
 325                                 sll_print(ndo, sllp, length + SLL_HDR_LEN);
 326                         if (!ndo->ndo_suppress_default_print)
 327                                 ND_DEFAULTPRINT(p, caplen);
 328                 }
 329         }
 330
 331         ndo->ndo_ll_hdr_len += hdrlen;
 332 }
 333
 334 static void
 335 sll2_print(netdissect_options *ndo, const struct sll2_header *sllp, u_int length)
 336 {
 337         u_short ether_type;
 338
 339         ndo->ndo_protocol = "sll2";
 340         ND_PRINT("ifindex %u ", GET_BE_U_4(sllp->sll2_if_index));
 341
 342         /*
 343          * XXX - check the link-layer address type value?
 344          * For now, we just assume 6 means Ethernet.
 345          * XXX - print others as strings of hex?
 346          */
 347         if (GET_U_1(sllp->sll2_halen) == MAC48_LEN)
 348                 ND_PRINT("%s ", GET_MAC48_STRING(sllp->sll2_addr));
 349
 350         if (!ndo->ndo_qflag) {
 351                 ether_type = GET_BE_U_2(sllp->sll2_protocol);
 352
 353                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 354                         /*
 355                          * Not an Ethernet type; what type is it?
 356                          */
 357                         switch (ether_type) {
 358
 359                         case LINUX_SLL_P_802_3:
 360                                 /*
 361                                  * Ethernet_802.3 IPX frame.
 362                                  */
 363                                 ND_PRINT("802.3");
 364                                 break;
 365
 366                         case LINUX_SLL_P_802_2:
 367                                 /*
 368                                  * 802.2.
 369                                  */
 370                                 ND_PRINT("802.2");
 371                                 break;
 372
 373                         default:
 374                                 /*
 375                                  * What is it?
 376                                  */
 377                                 ND_PRINT("ethertype Unknown (0x%04x)",
 378                                     ether_type);
 379                                 break;
 380                         }
 381                 } else {
 382                         ND_PRINT("ethertype %s (0x%04x)",
 383                             tok2str(ethertype_values, "Unknown", ether_type),
 384                             ether_type);
 385                 }
 386                 ND_PRINT(", length %u: ", length);
 387         }
 388 }
 389
 390 /*
 391  * This is the top level routine of the printer.  'p' points to the
 392  * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp,
 393  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
 394  * is the number of bytes actually captured.
 395  *
 396  * On Linux, we attempt to look up the interface index and print the
 397  * name of the interface on which the packet arrived or was sent.
 398  *
 399  * This look up is only likely to work well if done on the same machine
 400  * as the one on which the capture was done, as the interface with a
 401  * given index on the latter machine is unlikely to have the same
 402  * name as the interface with that index on the former machine.
 403  *
 404  * As DLT_LINUX_SLL2 live captures are supported only on Linux, this
 405  * means that if the machine on which we're reading the file isn't
 406  * running Linux, it's probably not the machine that captured the file,
 407  * so we don't bother trying to do the lookup on non-Linux machines.
 408  */
 409 void
 410 sll2_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
 411 {
 412         u_int caplen = h->caplen;
 413         u_int length = h->len;
 414         const struct sll2_header *sllp;
 415         u_short hatype;
 416         u_short ether_type;
 417         int llc_hdrlen;
 418         u_int hdrlen;
 419 #ifdef __linux__
 420         uint32_t if_index;
 421         char ifname[IF_NAMESIZE];
 422 #endif
 423
 424         ndo->ndo_protocol = "sll2";
 425         ND_TCHECK_LEN(p, SLL2_HDR_LEN);
 426
 427         sllp = (const struct sll2_header *)p;
 428 #ifdef __linux__
 429         if_index = GET_BE_U_4(sllp->sll2_if_index);
 430         if (!if_indextoname(if_index, ifname))
 431                 strncpy(ifname, "?", 2);
 432         ND_PRINT("%-5s ", ifname);
 433 #endif
 434
 435         ND_PRINT("%-3s ",
 436                  tok2str(sll_pkttype_values, "?", GET_U_1(sllp->sll2_pkttype)));
 437
 438         if (ndo->ndo_eflag)
 439                 sll2_print(ndo, sllp, length);
 440
 441         /*
 442          * Go past the cooked-mode header.
 443          */
 444         length -= SLL2_HDR_LEN;
 445         caplen -= SLL2_HDR_LEN;
 446         p += SLL2_HDR_LEN;
 447         hdrlen = SLL2_HDR_LEN;
 448
 449         hatype = GET_BE_U_2(sllp->sll2_hatype);
 450         switch (hatype) {
 451
 452         case 803:
 453                 /*
 454                  * This is an packet with a radiotap header;
 455                  * just dissect the payload as such.
 456                  */
 457                 ndo->ndo_ll_hdr_len += SLL2_HDR_LEN;
 458                 ndo->ndo_ll_hdr_len += ieee802_11_radio_print(ndo, p, length, caplen);
 459                 return;
 460         }
 461         ether_type = GET_BE_U_2(sllp->sll2_protocol);
 462
 463 recurse:
 464         /*
 465          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 466          * packet type?
 467          */
 468         if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 469                 /*
 470                  * Yes - what type is it?
 471                  */
 472                 switch (ether_type) {
 473
 474                 case LINUX_SLL_P_802_3:
 475                         /*
 476                          * Ethernet_802.3 IPX frame.
 477                          */
 478                         ipx_print(ndo, p, length);
 479                         break;
 480
 481                 case LINUX_SLL_P_802_2:
 482                         /*
 483                          * 802.2.
 484                          * Try to print the LLC-layer header & higher layers.
 485                          */
 486                         llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
 487                         if (llc_hdrlen < 0)
 488                                 goto unknown;   /* unknown LLC type */
 489                         hdrlen += llc_hdrlen;
 490                         break;
 491
 492                 default:
 493                         /*FALLTHROUGH*/
 494
 495                 unknown:
 496                         /* packet type not known, print raw packet */
 497                         if (!ndo->ndo_suppress_default_print)
 498                                 ND_DEFAULTPRINT(p, caplen);
 499                         break;
 500                 }
 501         } else if (ether_type == ETHERTYPE_8021Q) {
 502                 /*
 503                  * Print VLAN information, and then go back and process
 504                  * the enclosed type field.
 505                  */
 506                 if (caplen < 4) {
 507                         ndo->ndo_protocol = "vlan";
 508                         nd_print_trunc(ndo);
 509                         ndo->ndo_ll_hdr_len += hdrlen + caplen;
 510                         return;
 511                 }
 512                 if (ndo->ndo_eflag) {
 513                         uint16_t tag = GET_BE_U_2(p);
 514
 515                         ND_PRINT("%s, ", ieee8021q_tci_string(tag));
 516                 }
 517
 518                 ether_type = GET_BE_U_2(p + 2);
 519                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL)
 520                         ether_type = LINUX_SLL_P_802_2;
 521                 if (!ndo->ndo_qflag) {
 522                         ND_PRINT("ethertype %s, ",
 523                             tok2str(ethertype_values, "Unknown", ether_type));
 524                 }
 525                 p += 4;
 526                 length -= 4;
 527                 caplen -= 4;
 528                 hdrlen += 4;
 529                 goto recurse;
 530         } else {
 531                 if (ethertype_print(ndo, ether_type, p, length, caplen, NULL, NULL) == 0) {
 532                         /* ether_type not known, print raw packet */
 533                         if (!ndo->ndo_eflag)
 534                                 sll2_print(ndo, sllp, length + SLL2_HDR_LEN);
 535                         if (!ndo->ndo_suppress_default_print)
 536                                 ND_DEFAULTPRINT(p, caplen);
 537                 }
 538         }
 539
 540         ndo->ndo_ll_hdr_len += hdrlen;
 541 }