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 ",
 158                  tok2str(sll_pkttype_values,"?",GET_BE_U_2(sllp->sll_pkttype)));
 159
 160         /*
 161          * XXX - check the link-layer address type value?
 162          * For now, we just assume 6 means Ethernet.
 163          * XXX - print others as strings of hex?
 164          */
 165         if (GET_BE_U_2(sllp->sll_halen) == 6)
 166                 ND_PRINT("%s ", GET_ETHERADDR_STRING(sllp->sll_addr));
 167
 168         if (!ndo->ndo_qflag) {
 169                 ether_type = GET_BE_U_2(sllp->sll_protocol);
 170
 171                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 172                         /*
 173                          * Not an Ethernet type; what type is it?
 174                          */
 175                         switch (ether_type) {
 176
 177                         case LINUX_SLL_P_802_3:
 178                                 /*
 179                                  * Ethernet_802.3 IPX frame.
 180                                  */
 181                                 ND_PRINT("802.3");
 182                                 break;
 183
 184                         case LINUX_SLL_P_802_2:
 185                                 /*
 186                                  * 802.2.
 187                                  */
 188                                 ND_PRINT("802.2");
 189                                 break;
 190
 191                         default:
 192                                 /*
 193                                  * What is it?
 194                                  */
 195                                 ND_PRINT("ethertype Unknown (0x%04x)",
 196                                     ether_type);
 197                                 break;
 198                         }
 199                 } else {
 200                         ND_PRINT("ethertype %s (0x%04x)",
 201                             tok2str(ethertype_values, "Unknown", ether_type),
 202                             ether_type);
 203                 }
 204                 ND_PRINT(", length %u: ", length);
 205         }
 206 }
 207
 208 /*
 209  * This is the top level routine of the printer.  'p' points to the
 210  * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp,
 211  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
 212  * is the number of bytes actually captured.
 213  */
 214 u_int
 215 sll_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
 216 {
 217         u_int caplen = h->caplen;
 218         u_int length = h->len;
 219         const struct sll_header *sllp;
 220         u_short hatype;
 221         u_short ether_type;
 222         int llc_hdrlen;
 223         u_int hdrlen;
 224
 225         ndo->ndo_protocol = "sll_if";
 226         if (caplen < SLL_HDR_LEN) {
 227                 /*
 228                  * XXX - this "can't happen" because "pcap-linux.c" always
 229                  * adds this many bytes of header to every packet in a
 230                  * cooked socket capture.
 231                  */
 232                 nd_print_trunc(ndo);
 233                 return (caplen);
 234         }
 235
 236         sllp = (const struct sll_header *)p;
 237
 238         if (ndo->ndo_eflag)
 239                 sll_print(ndo, sllp, length);
 240
 241         /*
 242          * Go past the cooked-mode header.
 243          */
 244         length -= SLL_HDR_LEN;
 245         caplen -= SLL_HDR_LEN;
 246         p += SLL_HDR_LEN;
 247         hdrlen = SLL_HDR_LEN;
 248
 249         hatype = GET_BE_U_2(sllp->sll_hatype);
 250         switch (hatype) {
 251
 252         case 803:
 253                 /*
 254                  * This is an packet with a radiotap header;
 255                  * just dissect the payload as such.
 256                  */
 257                 return (SLL_HDR_LEN + ieee802_11_radio_print(ndo, p, length, caplen));
 258         }
 259         ether_type = GET_BE_U_2(sllp->sll_protocol);
 260
 261 recurse:
 262         /*
 263          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 264          * packet type?
 265          */
 266         if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 267                 /*
 268                  * Yes - what type is it?
 269                  */
 270                 switch (ether_type) {
 271
 272                 case LINUX_SLL_P_802_3:
 273                         /*
 274                          * Ethernet_802.3 IPX frame.
 275                          */
 276                         ipx_print(ndo, p, length);
 277                         break;
 278
 279                 case LINUX_SLL_P_802_2:
 280                         /*
 281                          * 802.2.
 282                          * Try to print the LLC-layer header & higher layers.
 283                          */
 284                         llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
 285                         if (llc_hdrlen < 0)
 286                                 goto unknown;   /* unknown LLC type */
 287                         hdrlen += llc_hdrlen;
 288                         break;
 289
 290                 default:
 291                         /*FALLTHROUGH*/
 292
 293                 unknown:
 294                         /* packet type not known, print raw packet */
 295                         if (!ndo->ndo_suppress_default_print)
 296                                 ND_DEFAULTPRINT(p, caplen);
 297                         break;
 298                 }
 299         } else if (ether_type == ETHERTYPE_8021Q) {
 300                 /*
 301                  * Print VLAN information, and then go back and process
 302                  * the enclosed type field.
 303                  */
 304                 if (caplen < 4) {
 305                         ndo->ndo_protocol = "vlan";
 306                         nd_print_trunc(ndo);
 307                         return (hdrlen + caplen);
 308                 }
 309                 if (ndo->ndo_eflag) {
 310                         uint16_t tag = GET_BE_U_2(p);
 311
 312                         ND_PRINT("%s, ", ieee8021q_tci_string(tag));
 313                 }
 314
 315                 ether_type = GET_BE_U_2(p + 2);
 316                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL)
 317                         ether_type = LINUX_SLL_P_802_2;
 318                 if (!ndo->ndo_qflag) {
 319                         ND_PRINT("ethertype %s, ",
 320                             tok2str(ethertype_values, "Unknown", ether_type));
 321                 }
 322                 p += 4;
 323                 length -= 4;
 324                 caplen -= 4;
 325                 hdrlen += 4;
 326                 goto recurse;
 327         } else {
 328                 if (ethertype_print(ndo, ether_type, p, length, caplen, NULL, NULL) == 0) {
 329                         /* ether_type not known, print raw packet */
 330                         if (!ndo->ndo_eflag)
 331                                 sll_print(ndo, sllp, length + SLL_HDR_LEN);
 332                         if (!ndo->ndo_suppress_default_print)
 333                                 ND_DEFAULTPRINT(p, caplen);
 334                 }
 335         }
 336
 337         return (hdrlen);
 338 }
 339
 340 static void
 341 sll2_print(netdissect_options *ndo, const struct sll2_header *sllp, u_int length)
 342 {
 343         u_short ether_type;
 344
 345         ndo->ndo_protocol = "sll2";
 346         ND_PRINT("ifindex %u ", GET_BE_U_4(sllp->sll2_if_index));
 347
 348         /*
 349          * XXX - check the link-layer address type value?
 350          * For now, we just assume 6 means Ethernet.
 351          * XXX - print others as strings of hex?
 352          */
 353         if (GET_U_1(sllp->sll2_halen) == 6)
 354                 ND_PRINT("%s ", GET_ETHERADDR_STRING(sllp->sll2_addr));
 355
 356         if (!ndo->ndo_qflag) {
 357                 ether_type = GET_BE_U_2(sllp->sll2_protocol);
 358
 359                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 360                         /*
 361                          * Not an Ethernet type; what type is it?
 362                          */
 363                         switch (ether_type) {
 364
 365                         case LINUX_SLL_P_802_3:
 366                                 /*
 367                                  * Ethernet_802.3 IPX frame.
 368                                  */
 369                                 ND_PRINT("802.3");
 370                                 break;
 371
 372                         case LINUX_SLL_P_802_2:
 373                                 /*
 374                                  * 802.2.
 375                                  */
 376                                 ND_PRINT("802.2");
 377                                 break;
 378
 379                         default:
 380                                 /*
 381                                  * What is it?
 382                                  */
 383                                 ND_PRINT("ethertype Unknown (0x%04x)",
 384                                     ether_type);
 385                                 break;
 386                         }
 387                 } else {
 388                         ND_PRINT("ethertype %s (0x%04x)",
 389                             tok2str(ethertype_values, "Unknown", ether_type),
 390                             ether_type);
 391                 }
 392                 ND_PRINT(", length %u: ", length);
 393         }
 394 }
 395
 396 /*
 397  * This is the top level routine of the printer.  'p' points to the
 398  * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp,
 399  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
 400  * is the number of bytes actually captured.
 401  */
 402 u_int
 403 sll2_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
 404 {
 405         u_int caplen = h->caplen;
 406         u_int length = h->len;
 407         const struct sll2_header *sllp;
 408         u_short hatype;
 409         u_short ether_type;
 410         int llc_hdrlen;
 411         u_int hdrlen;
 412 #ifdef HAVE_NET_IF_H
 413         uint32_t if_index;
 414         char ifname[IF_NAMESIZE];
 415 #endif
 416
 417         ndo->ndo_protocol = "sll2_if";
 418         if (caplen < SLL2_HDR_LEN) {
 419                 /*
 420                  * XXX - this "can't happen" because "pcap-linux.c" always
 421                  * adds this many bytes of header to every packet in a
 422                  * cooked socket capture.
 423                  */
 424                 nd_print_trunc(ndo);
 425                 return (caplen);
 426         }
 427
 428         sllp = (const struct sll2_header *)p;
 429 #ifdef HAVE_NET_IF_H
 430         if_index = GET_BE_U_4(sllp->sll2_if_index);
 431         if (!if_indextoname(if_index, ifname))
 432                 strncpy(ifname, "?", 2);
 433         ND_PRINT("%-5s ", ifname);
 434 #endif
 435
 436         ND_PRINT("%-3s ",
 437                  tok2str(sll_pkttype_values, "?", GET_U_1(sllp->sll2_pkttype)));
 438
 439         if (ndo->ndo_eflag)
 440                 sll2_print(ndo, sllp, length);
 441
 442         /*
 443          * Go past the cooked-mode header.
 444          */
 445         length -= SLL2_HDR_LEN;
 446         caplen -= SLL2_HDR_LEN;
 447         p += SLL2_HDR_LEN;
 448         hdrlen = SLL2_HDR_LEN;
 449
 450         hatype = GET_BE_U_2(sllp->sll2_hatype);
 451         switch (hatype) {
 452
 453         case 803:
 454                 /*
 455                  * This is an packet with a radiotap header;
 456                  * just dissect the payload as such.
 457                  */
 458                 return (SLL_HDR_LEN + ieee802_11_radio_print(ndo, p, length, caplen));
 459         }
 460         ether_type = GET_BE_U_2(sllp->sll2_protocol);
 461
 462 recurse:
 463         /*
 464          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 465          * packet type?
 466          */
 467         if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 468                 /*
 469                  * Yes - what type is it?
 470                  */
 471                 switch (ether_type) {
 472
 473                 case LINUX_SLL_P_802_3:
 474                         /*
 475                          * Ethernet_802.3 IPX frame.
 476                          */
 477                         ipx_print(ndo, p, length);
 478                         break;
 479
 480                 case LINUX_SLL_P_802_2:
 481                         /*
 482                          * 802.2.
 483                          * Try to print the LLC-layer header & higher layers.
 484                          */
 485                         llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
 486                         if (llc_hdrlen < 0)
 487                                 goto unknown;   /* unknown LLC type */
 488                         hdrlen += llc_hdrlen;
 489                         break;
 490
 491                 default:
 492                         /*FALLTHROUGH*/
 493
 494                 unknown:
 495                         /* packet type not known, print raw packet */
 496                         if (!ndo->ndo_suppress_default_print)
 497                                 ND_DEFAULTPRINT(p, caplen);
 498                         break;
 499                 }
 500         } else if (ether_type == ETHERTYPE_8021Q) {
 501                 /*
 502                  * Print VLAN information, and then go back and process
 503                  * the enclosed type field.
 504                  */
 505                 if (caplen < 4) {
 506                         ndo->ndo_protocol = "vlan";
 507                         nd_print_trunc(ndo);
 508                         return (hdrlen + caplen);
 509                 }
 510                 if (ndo->ndo_eflag) {
 511                         uint16_t tag = GET_BE_U_2(p);
 512
 513                         ND_PRINT("%s, ", ieee8021q_tci_string(tag));
 514                 }
 515
 516                 ether_type = GET_BE_U_2(p + 2);
 517                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL)
 518                         ether_type = LINUX_SLL_P_802_2;
 519                 if (!ndo->ndo_qflag) {
 520                         ND_PRINT("ethertype %s, ",
 521                             tok2str(ethertype_values, "Unknown", ether_type));
 522                 }
 523                 p += 4;
 524                 length -= 4;
 525                 caplen -= 4;
 526                 hdrlen += 4;
 527                 goto recurse;
 528         } else {
 529                 if (ethertype_print(ndo, ether_type, p, length, caplen, NULL, NULL) == 0) {
 530                         /* ether_type not known, print raw packet */
 531                         if (!ndo->ndo_eflag)
 532                                 sll2_print(ndo, sllp, length + SLL_HDR_LEN);
 533                         if (!ndo->ndo_suppress_default_print)
 534                                 ND_DEFAULTPRINT(p, caplen);
 535                 }
 536         }
 537
 538         return (hdrlen);
 539 }