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print-llc.c

/*
 * Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997
 *    The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Code by Matt Thomas, Digital Equipment Corporation
 *    with an awful lot of hacking by Jeffrey Mogul, DECWRL
 */

#ifndef lint
static const char rcsid[] _U_ =
    "@(#) $Header: /tcpdump/master/tcpdump/print-llc.c,v 1.53.2.3 2003/12/29 22:33:18 hannes Exp $";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <tcpdump-stdinc.h>

#include <stdio.h>
#include <string.h>

#include "interface.h"
#include "addrtoname.h"
#include "extract.h"                /* must come after interface.h */

#include "llc.h"
#include "ethertype.h"

static struct tok llc_values[] = {
        { LLCSAP_NULL,     "Null" },
        { LLCSAP_GLOBAL,   "Global" },
        { LLCSAP_8021B_I,  "802.1B I" },
        { LLCSAP_8021B_G,  "802.1B G" },
        { LLCSAP_IP,       "IP" },
        { LLCSAP_PROWAYNM, "ProWay NM" },
        { LLCSAP_8021D,    "STP" },
        { LLCSAP_RS511,    "RS511" },
        { LLCSAP_ISO8208,  "ISO8208" },
        { LLCSAP_PROWAY,   "ProWay" },
        { LLCSAP_SNAP,     "SNAP" },
        { LLCSAP_IPX,      "IPX" },
        { LLCSAP_NETBEUI,  "NetBeui" },
        { LLCSAP_ISONS,    "OSI" },
};

static struct tok cmd2str[] = {
      { LLC_UI,   "ui" },
      { LLC_TEST, "test" },
      { LLC_XID,  "xid" },
      { LLC_UA,   "ua" },
      { LLC_DISC, "disc" },
      { LLC_DM,   "dm" },
      { LLC_SABME,      "sabme" },
      { LLC_FRMR, "frmr" },
      { 0,        NULL }
};

/*
 * Returns non-zero IFF it succeeds in printing the header
 */
int
llc_print(const u_char *p, u_int length, u_int caplen,
        const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
{
      struct llc llc;
      register u_short et;
      u_int16_t control;
      register int ret;

      if (caplen < 3) {
            (void)printf("[|llc]");
            default_print((u_char *)p, caplen);
            return(0);
      }

      /* Watch out for possible alignment problems */
      memcpy((char *)&llc, (char *)p, min(caplen, sizeof(llc)));

      if (eflag)
        printf("LLC, dsap %s (0x%02x), ssap %s (0x%02x), cmd 0x%02x, ",
                 tok2str(llc_values,"Unknown",llc.dsap),
             llc.dsap,
                 tok2str(llc_values,"Unknown",llc.ssap),
             llc.ssap,
             llc.llcu);

      if (llc.ssap == LLCSAP_GLOBAL && llc.dsap == LLCSAP_GLOBAL) {
            /*
             * This is an Ethernet_802.3 IPX frame; it has an
             * 802.3 header (i.e., an Ethernet header where the
             * type/length field is <= ETHERMTU, i.e. it's a length
             * field, not a type field), but has no 802.2 header -
             * the IPX packet starts right after the Ethernet header,
             * with a signature of two bytes of 0xFF (which is
             * LLCSAP_GLOBAL).
             *
             * (It might also have been an Ethernet_802.3 IPX at
             * one time, but got bridged onto another network,
             * such as an 802.11 network; this has appeared in at
             * least one capture file.)
             */
            printf("(NOV-802.3) ");
            ipx_print(p, length);
            return (1);
      }

      if (llc.ssap == LLCSAP_8021D && llc.dsap == LLCSAP_8021D) {
            stp_print(p, length);
            return (1);
      }

      if (llc.ssap == LLCSAP_IP && llc.dsap == LLCSAP_IP) {
            ip_print(p+4, length-4);
            return (1);
      }

      if (llc.ssap == LLCSAP_IPX && llc.dsap == LLCSAP_IPX &&
          llc.llcui == LLC_UI) {
            /*
             * This is an Ethernet_802.2 IPX frame, with an 802.3
             * header and an 802.2 LLC header with the source and
             * destination SAPs being the IPX SAP.
             *
             * Skip DSAP, LSAP, and control field.
             */
            printf("(NOV-802.2) ");
            p += 3;
            length -= 3;
            caplen -= 3;
            ipx_print(p, length);
            return (1);
      }

#ifdef TCPDUMP_DO_SMB
      if (llc.ssap == LLCSAP_NETBEUI && llc.dsap == LLCSAP_NETBEUI
          && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
            /*
             * we don't actually have a full netbeui parser yet, but the
             * smb parser can handle many smb-in-netbeui packets, which
             * is very useful, so we call that
             *
             * We don't call it for S frames, however, just I frames
             * (which are frames that don't have the low-order bit,
             * LLC_S_FMT, set in the first byte of the control field)
             * and UI frames (whose control field is just 3, LLC_U_FMT).
             */

            /*
             * Skip the DSAP and LSAP.
             */
            p += 2;
            length -= 2;
            caplen -= 2;

            /*
             * OK, what type of LLC frame is this?  The length
             * of the control field depends on that - I frames
             * have a two-byte control field, and U frames have
             * a one-byte control field.
             */
            if (llc.llcu == LLC_U_FMT) {
                  control = llc.llcu;
                  p += 1;
                  length -= 1;
                  caplen -= 1;
            } else {
                  /*
                   * The control field in I and S frames is
                   * little-endian.
                   */
                  control = EXTRACT_LE_16BITS(&llc.llcu);
                  p += 2;
                  length -= 2;
                  caplen -= 2;
            }
            netbeui_print(control, p, length);
            return (1);
      }
#endif
      if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
          && llc.llcui == LLC_UI) {
            isoclns_print(p + 3, length - 3, caplen - 3);
            return (1);
      }

      if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
          && llc.llcui == LLC_UI) {
            u_int32_t orgcode;

            if (caplen < sizeof(llc)) {
                  (void)printf("[|llc-snap]");
                  default_print((u_char *)p, caplen);
                  return (0);
            }

            caplen -= sizeof(llc);
            length -= sizeof(llc);
            p += sizeof(llc);

            orgcode = EXTRACT_24BITS(&llc.llc_orgcode[0]);
            et = EXTRACT_16BITS(&llc.llc_ethertype[0]);
            /*
             * XXX - what *is* the right bridge pad value here?
             * Does anybody ever bridge one form of LAN traffic
             * over a networking type that uses 802.2 LLC?
             */
            ret = snap_print(p, length, caplen, extracted_ethertype,
                orgcode, et, 2);
            if (ret)
                  return (ret);
      }

      if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
            if (eflag || esrc == NULL || edst == NULL)
                  (void)printf("%s ", llcsap_string(llc.dsap));
            else
                  (void)printf("%s > %s %s ",
                              etheraddr_string(esrc),
                              etheraddr_string(edst),
                              llcsap_string(llc.dsap));
      } else {
            if (eflag || esrc == NULL || edst == NULL)
                  (void)printf("%s > %s ",
                        llcsap_string(llc.ssap & ~LLC_GSAP),
                        llcsap_string(llc.dsap));
            else
                  (void)printf("%s %s > %s %s ",
                        etheraddr_string(esrc),
                        llcsap_string(llc.ssap & ~LLC_GSAP),
                        etheraddr_string(edst),
                        llcsap_string(llc.dsap));
      }

      if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
            u_int16_t cmd;
            const char *m;
            char f;

            cmd = LLC_U_CMD(llc.llcu);
            m = tok2str(cmd2str, "%02x", cmd);
            switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
                  case 0:                 f = 'C'; break;
                  case LLC_GSAP:          f = 'R'; break;
                  case LLC_U_POLL:  f = 'P'; break;
                  case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
                  default:          f = '?'; break;
            }

            printf("%s/%c", m, f);

            p += 3;
            length -= 3;
            caplen -= 3;

            if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
                  if (*p == LLC_XID_FI) {
                        printf(": %02x %02x", p[1], p[2]);
                        p += 3;
                        length -= 3;
                        caplen -= 3;
                  }
            }
      } else {
            char f;

            /*
             * The control field in I and S frames is little-endian.
             */
            control = EXTRACT_LE_16BITS(&llc.llcu);
            switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
                  case 0:                 f = 'C'; break;
                  case LLC_GSAP:          f = 'R'; break;
                  case LLC_IS_POLL: f = 'P'; break;
                  case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
                  default:          f = '?'; break;
            }

            if ((control & LLC_S_FMT) == LLC_S_FMT) {
                  static const char *llc_s[] = { "rr", "rej", "rnr", "03" };
                  (void)printf("%s (r=%d,%c)",
                        llc_s[LLC_S_CMD(control)],
                        LLC_IS_NR(control),
                        f);
            } else {
                  (void)printf("I (s=%d,r=%d,%c)",
                        LLC_I_NS(control),
                        LLC_IS_NR(control),
                        f);
            }
            p += 4;
            length -= 4;
            caplen -= 4;
      }
      (void)printf(" len=%d", length);
      return(1);
}

int
snap_print(const u_char *p, u_int length, u_int caplen,
    u_short *extracted_ethertype, u_int32_t orgcode, u_short et,
    u_int bridge_pad)
{
      register int ret;

      switch (orgcode) {
      case OUI_ENCAP_ETHER:
      case OUI_CISCO_90:
            /*
             * This is an encapsulated Ethernet packet,
             * or a packet bridged by some piece of
             * Cisco hardware; the protocol ID is
             * an Ethernet protocol type.
             */
            ret = ether_encap_print(et, p, length, caplen,
                extracted_ethertype);
            if (ret)
                  return (ret);
            break;

      case OUI_APPLETALK:
            if (et == ETHERTYPE_ATALK) {
                  /*
                   * No, I have no idea why Apple used one
                   * of their own OUIs, rather than
                   * 0x000000, and an Ethernet packet
                   * type, for Appletalk data packets,
                   * but used 0x000000 and an Ethernet
                   * packet type for AARP packets.
                   */
                  ret = ether_encap_print(et, p, length, caplen,
                      extracted_ethertype);
                  if (ret)
                        return (ret);
            }
            break;

      case OUI_CISCO:
            if (et == PID_CISCO_CDP) {
                  cdp_print(p, length, caplen);
                  return (1);
            }
            break;

      case OUI_RFC2684:
            switch (et) {

            case PID_RFC2684_ETH_FCS:
            case PID_RFC2684_ETH_NOFCS:
                  /*
                   * XXX - remove the last two bytes for
                   * PID_RFC2684_ETH_FCS?
                   */
                  /*
                   * Skip the padding.
                   */
                  caplen -= bridge_pad;
                  length -= bridge_pad;
                  p += bridge_pad;

                  /*
                   * What remains is an Ethernet packet.
                   */
                  ether_print(p, length, caplen);
                  return (1);

            case PID_RFC2684_802_5_FCS:
            case PID_RFC2684_802_5_NOFCS:
                  /*
                   * XXX - remove the last two bytes for
                   * PID_RFC2684_ETH_FCS?
                   */
                  /*
                   * Skip the padding, but not the Access
                   * Control field.
                   */
                  caplen -= bridge_pad;
                  length -= bridge_pad;
                  p += bridge_pad;

                  /*
                   * What remains is an 802.5 Token Ring
                   * packet.
                   */
                  token_print(p, length, caplen);
                  return (1);

            case PID_RFC2684_FDDI_FCS:
            case PID_RFC2684_FDDI_NOFCS:
                  /*
                   * XXX - remove the last two bytes for
                   * PID_RFC2684_ETH_FCS?
                   */
                  /*
                   * Skip the padding.
                   */
                  caplen -= bridge_pad + 1;
                  length -= bridge_pad + 1;
                  p += bridge_pad + 1;

                  /*
                   * What remains is an FDDI packet.
                   */
                  fddi_print(p, length, caplen);
                  return (1);

            case PID_RFC2684_BPDU:
                  stp_print(p, length);
                  return (1);
            }
      }
      return (0);
}

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