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 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #ifdef HAVE_NET_IF_H
  29 #include <net/if.h>
  30 #endif
  31
  32 #include "netdissect-stdinc.h"
  33
  34 #include "netdissect.h"
  35 #include "addrtoname.h"
  36 #include "ethertype.h"
  37 #include "extract.h"
  38
  39 /*
  40  * For captures on Linux cooked sockets, we construct a fake header
  41  * that includes:
  42  *
  43  *      a 2-byte "packet type" which is one of:
  44  *
  45  *              LINUX_SLL_HOST          packet was sent to us
  46  *              LINUX_SLL_BROADCAST     packet was broadcast
  47  *              LINUX_SLL_MULTICAST     packet was multicast
  48  *              LINUX_SLL_OTHERHOST     packet was sent to somebody else
  49  *              LINUX_SLL_OUTGOING      packet was sent *by* us;
  50  *
  51  *      a 2-byte Ethernet protocol field;
  52  *
  53  *      a 2-byte link-layer type;
  54  *
  55  *      a 2-byte link-layer address length;
  56  *
  57  *      an 8-byte source link-layer address, whose actual length is
  58  *      specified by the previous value.
  59  *
  60  * All fields except for the link-layer address are in network byte order.
  61  *
  62  * DO NOT change the layout of this structure, or change any of the
  63  * LINUX_SLL_ values below.  If you must change the link-layer header
  64  * for a "cooked" Linux capture, introduce a new DLT_ type (ask
  65  * "tcpdump-workers@lists.tcpdump.org" for one, so that you don't give it
  66  * a value that collides with a value already being used), and use the
  67  * new header in captures of that type, so that programs that can
  68  * handle DLT_LINUX_SLL captures will continue to handle them correctly
  69  * without any change, and so that capture files with different headers
  70  * can be told apart and programs that read them can dissect the
  71  * packets in them.
  72  *
  73  * This structure, and the #defines below, must be the same in the
  74  * libpcap and tcpdump versions of "sll.h".
  75  */
  76
  77 /*
  78  * A DLT_LINUX_SLL fake link-layer header.
  79  */
  80 #define SLL_HDR_LEN     16              /* total header length */
  81 #define SLL_ADDRLEN     8               /* length of address field */
  82
  83 struct sll_header {
  84         nd_uint16_t     sll_pkttype;    /* packet type */
  85         nd_uint16_t     sll_hatype;     /* link-layer address type */
  86         nd_uint16_t     sll_halen;      /* link-layer address length */
  87         nd_byte         sll_addr[SLL_ADDRLEN];  /* link-layer address */
  88         nd_uint16_t     sll_protocol;   /* protocol */
  89 };
  90
  91 /*
  92  * A DLT_LINUX_SLL2 fake link-layer header.
  93  */
  94 #define SLL2_HDR_LEN    20              /* total header length */
  95
  96 struct sll2_header {
  97         nd_uint16_t     sll2_protocol;          /* protocol */
  98         nd_uint16_t     sll2_reserved_mbz;      /* reserved - must be zero */
  99         nd_uint32_t     sll2_if_index;          /* 1-based interface index */
 100         nd_uint16_t     sll2_hatype;            /* link-layer address type */
 101         nd_uint8_t      sll2_pkttype;           /* packet type */
 102         nd_uint8_t      sll2_halen;             /* link-layer address length */
 103         nd_byte         sll2_addr[SLL_ADDRLEN]; /* link-layer address */
 104 };
 105
 106 /*
 107  * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the
 108  * PACKET_ values on Linux, but are defined here so that they're
 109  * available even on systems other than Linux, and so that they
 110  * don't change even if the PACKET_ values change.
 111  */
 112 #define LINUX_SLL_HOST          0
 113 #define LINUX_SLL_BROADCAST     1
 114 #define LINUX_SLL_MULTICAST     2
 115 #define LINUX_SLL_OTHERHOST     3
 116 #define LINUX_SLL_OUTGOING      4
 117
 118 /*
 119  * The LINUX_SLL_ values for "sll_protocol"; these correspond to the
 120  * ETH_P_ values on Linux, but are defined here so that they're
 121  * available even on systems other than Linux.  We assume, for now,
 122  * that the ETH_P_ values won't change in Linux; if they do, then:
 123  *
 124  *      if we don't translate them in "pcap-linux.c", capture files
 125  *      won't necessarily be readable if captured on a system that
 126  *      defines ETH_P_ values that don't match these values;
 127  *
 128  *      if we do translate them in "pcap-linux.c", that makes life
 129  *      unpleasant for the BPF code generator, as the values you test
 130  *      for in the kernel aren't the values that you test for when
 131  *      reading a capture file, so the fixup code run on BPF programs
 132  *      handed to the kernel ends up having to do more work.
 133  *
 134  * Add other values here as necessary, for handling packet types that
 135  * might show up on non-Ethernet, non-802.x networks.  (Not all the ones
 136  * in the Linux "if_ether.h" will, I suspect, actually show up in
 137  * captures.)
 138  */
 139 #define LINUX_SLL_P_802_3       0x0001  /* Novell 802.3 frames without 802.2 LLC header */
 140 #define LINUX_SLL_P_802_2       0x0004  /* 802.2 frames (not D/I/X Ethernet) */
 141
 142 static const struct tok sll_pkttype_values[] = {
 143     { LINUX_SLL_HOST, "In" },
 144     { LINUX_SLL_BROADCAST, "B" },
 145     { LINUX_SLL_MULTICAST, "M" },
 146     { LINUX_SLL_OTHERHOST, "P" },
 147     { LINUX_SLL_OUTGOING, "Out" },
 148     { 0, NULL}
 149 };
 150
 151 static void
 152 sll_print(netdissect_options *ndo, const struct sll_header *sllp, u_int length)
 153 {
 154         u_short ether_type;
 155
 156         ndo->ndo_protocol = "sll";
 157         ND_PRINT("%3s ",tok2str(sll_pkttype_values,"?",EXTRACT_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 (EXTRACT_BE_U_2(sllp->sll_halen) == 6)
 165                 ND_PRINT("%s ", etheraddr_string(ndo, sllp->sll_addr));
 166
 167         if (!ndo->ndo_qflag) {
 168                 ether_type = EXTRACT_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 u_int
 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 ether_type;
 220         int llc_hdrlen;
 221         u_int hdrlen;
 222
 223         ndo->ndo_protocol = "sll_if";
 224         if (caplen < SLL_HDR_LEN) {
 225                 /*
 226                  * XXX - this "can't happen" because "pcap-linux.c" always
 227                  * adds this many bytes of header to every packet in a
 228                  * cooked socket capture.
 229                  */
 230                 nd_print_trunc(ndo);
 231                 return (caplen);
 232         }
 233
 234         sllp = (const struct sll_header *)p;
 235
 236         if (ndo->ndo_eflag)
 237                 sll_print(ndo, sllp, length);
 238
 239         /*
 240          * Go past the cooked-mode header.
 241          */
 242         length -= SLL_HDR_LEN;
 243         caplen -= SLL_HDR_LEN;
 244         p += SLL_HDR_LEN;
 245         hdrlen = SLL_HDR_LEN;
 246
 247         ether_type = EXTRACT_BE_U_2(sllp->sll_protocol);
 248
 249 recurse:
 250         /*
 251          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 252          * packet type?
 253          */
 254         if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 255                 /*
 256                  * Yes - what type is it?
 257                  */
 258                 switch (ether_type) {
 259
 260                 case LINUX_SLL_P_802_3:
 261                         /*
 262                          * Ethernet_802.3 IPX frame.
 263                          */
 264                         ipx_print(ndo, p, length);
 265                         break;
 266
 267                 case LINUX_SLL_P_802_2:
 268                         /*
 269                          * 802.2.
 270                          * Try to print the LLC-layer header & higher layers.
 271                          */
 272                         llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
 273                         if (llc_hdrlen < 0)
 274                                 goto unknown;   /* unknown LLC type */
 275                         hdrlen += llc_hdrlen;
 276                         break;
 277
 278                 default:
 279                         /*FALLTHROUGH*/
 280
 281                 unknown:
 282                         /* packet type not known, print raw packet */
 283                         if (!ndo->ndo_suppress_default_print)
 284                                 ND_DEFAULTPRINT(p, caplen);
 285                         break;
 286                 }
 287         } else if (ether_type == ETHERTYPE_8021Q) {
 288                 /*
 289                  * Print VLAN information, and then go back and process
 290                  * the enclosed type field.
 291                  */
 292                 if (caplen < 4) {
 293                         ndo->ndo_protocol = "vlan";
 294                         nd_print_trunc(ndo);
 295                         return (hdrlen + caplen);
 296                 }
 297                 if (ndo->ndo_eflag) {
 298                         uint16_t tag = EXTRACT_BE_U_2(p);
 299
 300                         ND_PRINT("%s, ", ieee8021q_tci_string(tag));
 301                 }
 302
 303                 ether_type = EXTRACT_BE_U_2(p + 2);
 304                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL)
 305                         ether_type = LINUX_SLL_P_802_2;
 306                 if (!ndo->ndo_qflag) {
 307                         ND_PRINT("ethertype %s, ",
 308                             tok2str(ethertype_values, "Unknown", ether_type));
 309                 }
 310                 p += 4;
 311                 length -= 4;
 312                 caplen -= 4;
 313                 hdrlen += 4;
 314                 goto recurse;
 315         } else {
 316                 if (ethertype_print(ndo, ether_type, p, length, caplen, NULL, NULL) == 0) {
 317                         /* ether_type not known, print raw packet */
 318                         if (!ndo->ndo_eflag)
 319                                 sll_print(ndo, sllp, length + SLL_HDR_LEN);
 320                         if (!ndo->ndo_suppress_default_print)
 321                                 ND_DEFAULTPRINT(p, caplen);
 322                 }
 323         }
 324
 325         return (hdrlen);
 326 }
 327
 328 static void
 329 sll2_print(netdissect_options *ndo, const struct sll2_header *sllp, u_int length)
 330 {
 331         u_short ether_type;
 332
 333         ndo->ndo_protocol = "sll2";
 334         ND_PRINT("%3s ",tok2str(sll_pkttype_values,"?",EXTRACT_U_1(sllp->sll2_pkttype)));
 335
 336         /*
 337          * XXX - check the link-layer address type value?
 338          * For now, we just assume 6 means Ethernet.
 339          * XXX - print others as strings of hex?
 340          */
 341         if (EXTRACT_U_1(sllp->sll2_halen) == 6)
 342                 ND_PRINT("%s ", etheraddr_string(ndo, sllp->sll2_addr));
 343
 344         if (!ndo->ndo_qflag) {
 345                 ether_type = EXTRACT_BE_U_2(sllp->sll2_protocol);
 346
 347                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 348                         /*
 349                          * Not an Ethernet type; what type is it?
 350                          */
 351                         switch (ether_type) {
 352
 353                         case LINUX_SLL_P_802_3:
 354                                 /*
 355                                  * Ethernet_802.3 IPX frame.
 356                                  */
 357                                 ND_PRINT("802.3");
 358                                 break;
 359
 360                         case LINUX_SLL_P_802_2:
 361                                 /*
 362                                  * 802.2.
 363                                  */
 364                                 ND_PRINT("802.2");
 365                                 break;
 366
 367                         default:
 368                                 /*
 369                                  * What is it?
 370                                  */
 371                                 ND_PRINT("ethertype Unknown (0x%04x)",
 372                                     ether_type);
 373                                 break;
 374                         }
 375                 } else {
 376                         ND_PRINT("ethertype %s (0x%04x)",
 377                             tok2str(ethertype_values, "Unknown", ether_type),
 378                             ether_type);
 379                 }
 380                 ND_PRINT(", length %u: ", length);
 381         }
 382 }
 383
 384 /*
 385  * This is the top level routine of the printer.  'p' points to the
 386  * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp,
 387  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
 388  * is the number of bytes actually captured.
 389  */
 390 u_int
 391 sll2_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
 392 {
 393         u_int caplen = h->caplen;
 394         u_int length = h->len;
 395         const struct sll2_header *sllp;
 396         u_short ether_type;
 397         int llc_hdrlen;
 398         u_int hdrlen;
 399 #ifdef HAVE_NET_IF_H
 400         uint32_t if_index;
 401         char ifname[IF_NAMESIZE];
 402 #endif
 403
 404         ndo->ndo_protocol = "sll2_if";
 405         if (caplen < SLL2_HDR_LEN) {
 406                 /*
 407                  * XXX - this "can't happen" because "pcap-linux.c" always
 408                  * adds this many bytes of header to every packet in a
 409                  * cooked socket capture.
 410                  */
 411                 nd_print_trunc(ndo);
 412                 return (caplen);
 413         }
 414
 415         sllp = (const struct sll2_header *)p;
 416 #ifdef HAVE_NET_IF_H
 417         if_index = EXTRACT_BE_U_4(sllp->sll2_if_index);
 418         if (if_indextoname(if_index, ifname))
 419                 ND_PRINT("ifindex %u (%s) ", if_index, ifname);
 420         else
 421                 ND_PRINT("ifindex %u ", if_index);
 422 #endif
 423
 424         if (ndo->ndo_eflag)
 425                 sll2_print(ndo, sllp, length);
 426
 427         /*
 428          * Go past the cooked-mode header.
 429          */
 430         length -= SLL2_HDR_LEN;
 431         caplen -= SLL2_HDR_LEN;
 432         p += SLL2_HDR_LEN;
 433         hdrlen = SLL2_HDR_LEN;
 434
 435         ether_type = EXTRACT_BE_U_2(sllp->sll2_protocol);
 436
 437 recurse:
 438         /*
 439          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 440          * packet type?
 441          */
 442         if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 443                 /*
 444                  * Yes - what type is it?
 445                  */
 446                 switch (ether_type) {
 447
 448                 case LINUX_SLL_P_802_3:
 449                         /*
 450                          * Ethernet_802.3 IPX frame.
 451                          */
 452                         ipx_print(ndo, p, length);
 453                         break;
 454
 455                 case LINUX_SLL_P_802_2:
 456                         /*
 457                          * 802.2.
 458                          * Try to print the LLC-layer header & higher layers.
 459                          */
 460                         llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
 461                         if (llc_hdrlen < 0)
 462                                 goto unknown;   /* unknown LLC type */
 463                         hdrlen += llc_hdrlen;
 464                         break;
 465
 466                 default:
 467                         /*FALLTHROUGH*/
 468
 469                 unknown:
 470                         /* packet type not known, print raw packet */
 471                         if (!ndo->ndo_suppress_default_print)
 472                                 ND_DEFAULTPRINT(p, caplen);
 473                         break;
 474                 }
 475         } else if (ether_type == ETHERTYPE_8021Q) {
 476                 /*
 477                  * Print VLAN information, and then go back and process
 478                  * the enclosed type field.
 479                  */
 480                 if (caplen < 4) {
 481                         ndo->ndo_protocol = "vlan";
 482                         nd_print_trunc(ndo);
 483                         return (hdrlen + caplen);
 484                 }
 485                 if (ndo->ndo_eflag) {
 486                         uint16_t tag = EXTRACT_BE_U_2(p);
 487
 488                         ND_PRINT("%s, ", ieee8021q_tci_string(tag));
 489                 }
 490
 491                 ether_type = EXTRACT_BE_U_2(p + 2);
 492                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL)
 493                         ether_type = LINUX_SLL_P_802_2;
 494                 if (!ndo->ndo_qflag) {
 495                         ND_PRINT("ethertype %s, ",
 496                             tok2str(ethertype_values, "Unknown", ether_type));
 497                 }
 498                 p += 4;
 499                 length -= 4;
 500                 caplen -= 4;
 501                 hdrlen += 4;
 502                 goto recurse;
 503         } else {
 504                 if (ethertype_print(ndo, ether_type, p, length, caplen, NULL, NULL) == 0) {
 505                         /* ether_type not known, print raw packet */
 506                         if (!ndo->ndo_eflag)
 507                                 sll2_print(ndo, sllp, length + SLL_HDR_LEN);
 508                         if (!ndo->ndo_suppress_default_print)
 509                                 ND_DEFAULTPRINT(p, caplen);
 510                 }
 511         }
 512
 513         return (hdrlen);
 514 }