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 #include "netdissect-stdinc.h"
  29
  30 #include "netdissect.h"
  31 #include "addrtoname.h"
  32 #include "ethertype.h"
  33 #include "extract.h"
  34
  35 /*
  36  * For captures on Linux cooked sockets, we construct a fake header
  37  * that includes:
  38  *
  39  *      a 2-byte "packet type" which is one of:
  40  *
  41  *              LINUX_SLL_HOST          packet was sent to us
  42  *              LINUX_SLL_BROADCAST     packet was broadcast
  43  *              LINUX_SLL_MULTICAST     packet was multicast
  44  *              LINUX_SLL_OTHERHOST     packet was sent to somebody else
  45  *              LINUX_SLL_OUTGOING      packet was sent *by* us;
  46  *
  47  *      a 2-byte Ethernet protocol field;
  48  *
  49  *      a 2-byte link-layer type;
  50  *
  51  *      a 2-byte link-layer address length;
  52  *
  53  *      an 8-byte source link-layer address, whose actual length is
  54  *      specified by the previous value.
  55  *
  56  * All fields except for the link-layer address are in network byte order.
  57  *
  58  * DO NOT change the layout of this structure, or change any of the
  59  * LINUX_SLL_ values below.  If you must change the link-layer header
  60  * for a "cooked" Linux capture, introduce a new DLT_ type (ask
  61  * "tcpdump-workers@lists.tcpdump.org" for one, so that you don't give it
  62  * a value that collides with a value already being used), and use the
  63  * new header in captures of that type, so that programs that can
  64  * handle DLT_LINUX_SLL captures will continue to handle them correctly
  65  * without any change, and so that capture files with different headers
  66  * can be told apart and programs that read them can dissect the
  67  * packets in them.
  68  *
  69  * This structure, and the #defines below, must be the same in the
  70  * libpcap and tcpdump versions of "sll.h".
  71  */
  72
  73 /*
  74  * A DLT_LINUX_SLL fake link-layer header.
  75  */
  76 #define SLL_HDR_LEN     16              /* total header length */
  77 #define SLL_ADDRLEN     8               /* length of address field */
  78
  79 struct sll_header {
  80         nd_uint16_t     sll_pkttype;    /* packet type */
  81         nd_uint16_t     sll_hatype;     /* link-layer address type */
  82         nd_uint16_t     sll_halen;      /* link-layer address length */
  83         nd_byte         sll_addr[SLL_ADDRLEN];  /* link-layer address */
  84         nd_uint16_t     sll_protocol;   /* protocol */
  85 };
  86
  87 /*
  88  * A DLT_LINUX_SLL2 fake link-layer header.
  89  */
  90 #define SLL2_HDR_LEN    20              /* total header length */
  91
  92 struct sll2_header {
  93         nd_uint16_t     sll2_protocol;          /* protocol */
  94         nd_uint16_t     sll2_reserved_mbz;      /* reserved - must be zero */
  95         nd_uint32_t     sll2_if_index;          /* 1-based interface index */
  96         nd_uint16_t     sll2_hatype;            /* link-layer address type */
  97         nd_uint8_t      sll2_pkttype;           /* packet type */
  98         nd_uint8_t      sll2_halen;             /* link-layer address length */
  99         nd_byte         sll2_addr[SLL_ADDRLEN]; /* link-layer address */
 100 };
 101
 102 /*
 103  * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the
 104  * PACKET_ values on Linux, but are defined here so that they're
 105  * available even on systems other than Linux, and so that they
 106  * don't change even if the PACKET_ values change.
 107  */
 108 #define LINUX_SLL_HOST          0
 109 #define LINUX_SLL_BROADCAST     1
 110 #define LINUX_SLL_MULTICAST     2
 111 #define LINUX_SLL_OTHERHOST     3
 112 #define LINUX_SLL_OUTGOING      4
 113
 114 /*
 115  * The LINUX_SLL_ values for "sll_protocol"; these correspond to the
 116  * ETH_P_ values on Linux, but are defined here so that they're
 117  * available even on systems other than Linux.  We assume, for now,
 118  * that the ETH_P_ values won't change in Linux; if they do, then:
 119  *
 120  *      if we don't translate them in "pcap-linux.c", capture files
 121  *      won't necessarily be readable if captured on a system that
 122  *      defines ETH_P_ values that don't match these values;
 123  *
 124  *      if we do translate them in "pcap-linux.c", that makes life
 125  *      unpleasant for the BPF code generator, as the values you test
 126  *      for in the kernel aren't the values that you test for when
 127  *      reading a capture file, so the fixup code run on BPF programs
 128  *      handed to the kernel ends up having to do more work.
 129  *
 130  * Add other values here as necessary, for handling packet types that
 131  * might show up on non-Ethernet, non-802.x networks.  (Not all the ones
 132  * in the Linux "if_ether.h" will, I suspect, actually show up in
 133  * captures.)
 134  */
 135 #define LINUX_SLL_P_802_3       0x0001  /* Novell 802.3 frames without 802.2 LLC header */
 136 #define LINUX_SLL_P_802_2       0x0004  /* 802.2 frames (not D/I/X Ethernet) */
 137
 138 static const struct tok sll_pkttype_values[] = {
 139     { LINUX_SLL_HOST, "In" },
 140     { LINUX_SLL_BROADCAST, "B" },
 141     { LINUX_SLL_MULTICAST, "M" },
 142     { LINUX_SLL_OTHERHOST, "P" },
 143     { LINUX_SLL_OUTGOING, "Out" },
 144     { 0, NULL}
 145 };
 146
 147 static void
 148 sll_print(netdissect_options *ndo, const struct sll_header *sllp, u_int length)
 149 {
 150         u_short ether_type;
 151
 152         ndo->ndo_protocol = "sll";
 153         ND_PRINT("%3s ",tok2str(sll_pkttype_values,"?",EXTRACT_BE_U_2(sllp->sll_pkttype)));
 154
 155         /*
 156          * XXX - check the link-layer address type value?
 157          * For now, we just assume 6 means Ethernet.
 158          * XXX - print others as strings of hex?
 159          */
 160         if (EXTRACT_BE_U_2(sllp->sll_halen) == 6)
 161                 ND_PRINT("%s ", etheraddr_string(ndo, sllp->sll_addr));
 162
 163         if (!ndo->ndo_qflag) {
 164                 ether_type = EXTRACT_BE_U_2(sllp->sll_protocol);
 165
 166                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 167                         /*
 168                          * Not an Ethernet type; what type is it?
 169                          */
 170                         switch (ether_type) {
 171
 172                         case LINUX_SLL_P_802_3:
 173                                 /*
 174                                  * Ethernet_802.3 IPX frame.
 175                                  */
 176                                 ND_PRINT("802.3");
 177                                 break;
 178
 179                         case LINUX_SLL_P_802_2:
 180                                 /*
 181                                  * 802.2.
 182                                  */
 183                                 ND_PRINT("802.2");
 184                                 break;
 185
 186                         default:
 187                                 /*
 188                                  * What is it?
 189                                  */
 190                                 ND_PRINT("ethertype Unknown (0x%04x)",
 191                                     ether_type);
 192                                 break;
 193                         }
 194                 } else {
 195                         ND_PRINT("ethertype %s (0x%04x)",
 196                             tok2str(ethertype_values, "Unknown", ether_type),
 197                             ether_type);
 198                 }
 199                 ND_PRINT(", length %u: ", length);
 200         }
 201 }
 202
 203 /*
 204  * This is the top level routine of the printer.  'p' points to the
 205  * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp,
 206  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
 207  * is the number of bytes actually captured.
 208  */
 209 u_int
 210 sll_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
 211 {
 212         u_int caplen = h->caplen;
 213         u_int length = h->len;
 214         const struct sll_header *sllp;
 215         u_short ether_type;
 216         int llc_hdrlen;
 217         u_int hdrlen;
 218
 219         ndo->ndo_protocol = "sll_if";
 220         if (caplen < SLL_HDR_LEN) {
 221                 /*
 222                  * XXX - this "can't happen" because "pcap-linux.c" always
 223                  * adds this many bytes of header to every packet in a
 224                  * cooked socket capture.
 225                  */
 226                 nd_print_trunc(ndo);
 227                 return (caplen);
 228         }
 229
 230         sllp = (const struct sll_header *)p;
 231
 232         if (ndo->ndo_eflag)
 233                 sll_print(ndo, sllp, length);
 234
 235         /*
 236          * Go past the cooked-mode header.
 237          */
 238         length -= SLL_HDR_LEN;
 239         caplen -= SLL_HDR_LEN;
 240         p += SLL_HDR_LEN;
 241         hdrlen = SLL_HDR_LEN;
 242
 243         ether_type = EXTRACT_BE_U_2(sllp->sll_protocol);
 244
 245 recurse:
 246         /*
 247          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 248          * packet type?
 249          */
 250         if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 251                 /*
 252                  * Yes - what type is it?
 253                  */
 254                 switch (ether_type) {
 255
 256                 case LINUX_SLL_P_802_3:
 257                         /*
 258                          * Ethernet_802.3 IPX frame.
 259                          */
 260                         ipx_print(ndo, p, length);
 261                         break;
 262
 263                 case LINUX_SLL_P_802_2:
 264                         /*
 265                          * 802.2.
 266                          * Try to print the LLC-layer header & higher layers.
 267                          */
 268                         llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
 269                         if (llc_hdrlen < 0)
 270                                 goto unknown;   /* unknown LLC type */
 271                         hdrlen += llc_hdrlen;
 272                         break;
 273
 274                 default:
 275                         /*FALLTHROUGH*/
 276
 277                 unknown:
 278                         /* packet type not known, print raw packet */
 279                         if (!ndo->ndo_suppress_default_print)
 280                                 ND_DEFAULTPRINT(p, caplen);
 281                         break;
 282                 }
 283         } else if (ether_type == ETHERTYPE_8021Q) {
 284                 /*
 285                  * Print VLAN information, and then go back and process
 286                  * the enclosed type field.
 287                  */
 288                 if (caplen < 4) {
 289                         ND_PRINT("[|vlan]");
 290                         return (hdrlen + caplen);
 291                 }
 292                 if (length < 4) {
 293                         ND_PRINT("[|vlan]");
 294                         return (hdrlen + length);
 295                 }
 296                 if (ndo->ndo_eflag) {
 297                         uint16_t tag = EXTRACT_BE_U_2(p);
 298
 299                         ND_PRINT("%s, ", ieee8021q_tci_string(tag));
 300                 }
 301
 302                 ether_type = EXTRACT_BE_U_2(p + 2);
 303                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL)
 304                         ether_type = LINUX_SLL_P_802_2;
 305                 if (!ndo->ndo_qflag) {
 306                         ND_PRINT("ethertype %s, ",
 307                             tok2str(ethertype_values, "Unknown", ether_type));
 308                 }
 309                 p += 4;
 310                 length -= 4;
 311                 caplen -= 4;
 312                 hdrlen += 4;
 313                 goto recurse;
 314         } else {
 315                 if (ethertype_print(ndo, ether_type, p, length, caplen, NULL, NULL) == 0) {
 316                         /* ether_type not known, print raw packet */
 317                         if (!ndo->ndo_eflag)
 318                                 sll_print(ndo, sllp, length + SLL_HDR_LEN);
 319                         if (!ndo->ndo_suppress_default_print)
 320                                 ND_DEFAULTPRINT(p, caplen);
 321                 }
 322         }
 323
 324         return (hdrlen);
 325 }
 326
 327 static void
 328 sll2_print(netdissect_options *ndo, const struct sll2_header *sllp, u_int length)
 329 {
 330         u_short ether_type;
 331
 332         ndo->ndo_protocol = "sll2";
 333         ND_PRINT("%3s ",tok2str(sll_pkttype_values,"?",EXTRACT_BE_U_2(sllp->sll2_pkttype)));
 334
 335         /*
 336          * XXX - check the link-layer address type value?
 337          * For now, we just assume 6 means Ethernet.
 338          * XXX - print others as strings of hex?
 339          */
 340         if (EXTRACT_U_1(sllp->sll2_halen) == 6)
 341                 ND_PRINT("%s ", etheraddr_string(ndo, sllp->sll2_addr));
 342
 343         if (!ndo->ndo_qflag) {
 344                 ether_type = EXTRACT_BE_U_2(sllp->sll2_protocol);
 345
 346                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 347                         /*
 348                          * Not an Ethernet type; what type is it?
 349                          */
 350                         switch (ether_type) {
 351
 352                         case LINUX_SLL_P_802_3:
 353                                 /*
 354                                  * Ethernet_802.3 IPX frame.
 355                                  */
 356                                 ND_PRINT("802.3");
 357                                 break;
 358
 359                         case LINUX_SLL_P_802_2:
 360                                 /*
 361                                  * 802.2.
 362                                  */
 363                                 ND_PRINT("802.2");
 364                                 break;
 365
 366                         default:
 367                                 /*
 368                                  * What is it?
 369                                  */
 370                                 ND_PRINT("ethertype Unknown (0x%04x)",
 371                                     ether_type);
 372                                 break;
 373                         }
 374                 } else {
 375                         ND_PRINT("ethertype %s (0x%04x)",
 376                             tok2str(ethertype_values, "Unknown", ether_type),
 377                             ether_type);
 378                 }
 379                 ND_PRINT(", length %u: ", length);
 380         }
 381 }
 382
 383 /*
 384  * This is the top level routine of the printer.  'p' points to the
 385  * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp,
 386  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
 387  * is the number of bytes actually captured.
 388  */
 389 u_int
 390 sll2_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
 391 {
 392         u_int caplen = h->caplen;
 393         u_int length = h->len;
 394         const struct sll2_header *sllp;
 395         u_short ether_type;
 396         int llc_hdrlen;
 397         u_int hdrlen;
 398
 399         ndo->ndo_protocol = "sll2_if";
 400         if (caplen < SLL2_HDR_LEN) {
 401                 /*
 402                  * XXX - this "can't happen" because "pcap-linux.c" always
 403                  * adds this many bytes of header to every packet in a
 404                  * cooked socket capture.
 405                  */
 406                 nd_print_trunc(ndo);
 407                 return (caplen);
 408         }
 409
 410         sllp = (const struct sll2_header *)p;
 411
 412         if (ndo->ndo_eflag)
 413                 sll2_print(ndo, sllp, length);
 414
 415         /*
 416          * Go past the cooked-mode header.
 417          */
 418         length -= SLL2_HDR_LEN;
 419         caplen -= SLL2_HDR_LEN;
 420         p += SLL2_HDR_LEN;
 421         hdrlen = SLL2_HDR_LEN;
 422
 423         ether_type = EXTRACT_BE_U_2(sllp->sll2_protocol);
 424
 425 recurse:
 426         /*
 427          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 428          * packet type?
 429          */
 430         if (ether_type <= MAX_ETHERNET_LENGTH_VAL) {
 431                 /*
 432                  * Yes - what type is it?
 433                  */
 434                 switch (ether_type) {
 435
 436                 case LINUX_SLL_P_802_3:
 437                         /*
 438                          * Ethernet_802.3 IPX frame.
 439                          */
 440                         ipx_print(ndo, p, length);
 441                         break;
 442
 443                 case LINUX_SLL_P_802_2:
 444                         /*
 445                          * 802.2.
 446                          * Try to print the LLC-layer header & higher layers.
 447                          */
 448                         llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
 449                         if (llc_hdrlen < 0)
 450                                 goto unknown;   /* unknown LLC type */
 451                         hdrlen += llc_hdrlen;
 452                         break;
 453
 454                 default:
 455                         /*FALLTHROUGH*/
 456
 457                 unknown:
 458                         /* packet type not known, print raw packet */
 459                         if (!ndo->ndo_suppress_default_print)
 460                                 ND_DEFAULTPRINT(p, caplen);
 461                         break;
 462                 }
 463         } else if (ether_type == ETHERTYPE_8021Q) {
 464                 /*
 465                  * Print VLAN information, and then go back and process
 466                  * the enclosed type field.
 467                  */
 468                 if (caplen < 4) {
 469                         ND_PRINT("[|vlan]");
 470                         return (hdrlen + caplen);
 471                 }
 472                 if (length < 4) {
 473                         ND_PRINT("[|vlan]");
 474                         return (hdrlen + length);
 475                 }
 476                 if (ndo->ndo_eflag) {
 477                         uint16_t tag = EXTRACT_BE_U_2(p);
 478
 479                         ND_PRINT("%s, ", ieee8021q_tci_string(tag));
 480                 }
 481
 482                 ether_type = EXTRACT_BE_U_2(p + 2);
 483                 if (ether_type <= MAX_ETHERNET_LENGTH_VAL)
 484                         ether_type = LINUX_SLL_P_802_2;
 485                 if (!ndo->ndo_qflag) {
 486                         ND_PRINT("ethertype %s, ",
 487                             tok2str(ethertype_values, "Unknown", ether_type));
 488                 }
 489                 p += 4;
 490                 length -= 4;
 491                 caplen -= 4;
 492                 hdrlen += 4;
 493                 goto recurse;
 494         } else {
 495                 if (ethertype_print(ndo, ether_type, p, length, caplen, NULL, NULL) == 0) {
 496                         /* ether_type not known, print raw packet */
 497                         if (!ndo->ndo_eflag)
 498                                 sll2_print(ndo, sllp, length + SLL_HDR_LEN);
 499                         if (!ndo->ndo_suppress_default_print)
 500                                 ND_DEFAULTPRINT(p, caplen);
 501                 }
 502         }
 503
 504         return (hdrlen);
 505 }