/* packet-fddi.c
 * Routines for FDDI packet disassembly
 *
 * ANSI Standard X3T9.5/88-139, Rev 4.0
 *
 * ISO Standards 9314-N (N = 1 for PHY, N = 2 for MAC, N = 6 for SMT, etc.)
 *
 * Laurent Deniel <laurent.deniel@free.fr>
 *
 * $Id$
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <glib.h>

#include <epan/packet.h>
#include <epan/bitswap.h>
#include <epan/prefs.h>
#include "packet-fddi.h"
#include "packet-llc.h"
#include <epan/tap.h>

#include <epan/addr_resolv.h>

static int proto_fddi = -1;
static int hf_fddi_fc = -1;
static int hf_fddi_fc_clf = -1;
static int hf_fddi_fc_prio = -1;
static int hf_fddi_fc_smt_subtype = -1;
static int hf_fddi_fc_mac_subtype = -1;
static int hf_fddi_dst = -1;
static int hf_fddi_src = -1;
static int hf_fddi_addr = -1;

static gint ett_fddi = -1;
static gint ett_fddi_fc = -1;

static int fddi_tap = -1;

static gboolean fddi_padding = FALSE;

#define FDDI_PADDING            ((fddi_padding) ? 3 : 0)

/* FDDI Frame Control values */

#define FDDI_FC_VOID            0x00            /* Void frame */
#define FDDI_FC_NRT             0x80            /* Nonrestricted token */
#define FDDI_FC_RT              0xc0            /* Restricted token */
#define FDDI_FC_MAC             0xc0            /* MAC frame */
#define FDDI_FC_SMT             0x40            /* SMT frame */
#define FDDI_FC_SMT_INFO        0x41            /* SMT Info */
#define FDDI_FC_SMT_NSA         0x4F            /* SMT Next station adrs */
#define FDDI_FC_SMT_MIN         FDDI_FC_SMT_INFO
#define FDDI_FC_SMT_MAX         FDDI_FC_SMT_NSA
#define FDDI_FC_MAC_MIN         0xc1
#define FDDI_FC_MAC_BEACON      0xc2            /* MAC Beacon frame */
#define FDDI_FC_MAC_CLAIM       0xc3            /* MAC Claim frame */
#define FDDI_FC_MAC_MAX         0xcf
#define FDDI_FC_LLC_ASYNC       0x50            /* Async. LLC frame */
#define FDDI_FC_LLC_ASYNC_MIN   FDDI_FC_LLC_ASYNC
#define FDDI_FC_LLC_ASYNC_DEF   0x54
#define FDDI_FC_LLC_ASYNC_MAX   0x5f
#define FDDI_FC_LLC_SYNC        0xd0            /* Sync. LLC frame */
#define FDDI_FC_LLC_SYNC_MIN    FDDI_FC_LLC_SYNC
#define FDDI_FC_LLC_SYNC_MAX    0xd7
#define FDDI_FC_IMP_ASYNC       0x60            /* Implementor Async. */
#define FDDI_FC_IMP_ASYNC_MIN   FDDI_FC_IMP_ASYNC
#define FDDI_FC_IMP_ASYNC_MAX   0x6f
#define FDDI_FC_IMP_SYNC        0xe0            /* Implementor Synch. */

#define FDDI_FC_CLFF            0xF0            /* Class/Length/Format bits */
#define FDDI_FC_ZZZZ            0x0F            /* Control bits */

/*
 * Async frame ZZZZ bits:
 */
#define FDDI_FC_ASYNC_R         0x08            /* Reserved */
#define FDDI_FC_ASYNC_PRI       0x07            /* Priority */

#define CLFF_BITS(fc)   (((fc) & FDDI_FC_CLFF) >> 4)
#define ZZZZ_BITS(fc)   ((fc) & FDDI_FC_ZZZZ)

static const value_string clf_vals[] = {
  { CLFF_BITS(FDDI_FC_VOID),      "Void" },
  { CLFF_BITS(FDDI_FC_SMT),       "SMT" },
  { CLFF_BITS(FDDI_FC_LLC_ASYNC), "Async LLC" },
  { CLFF_BITS(FDDI_FC_IMP_ASYNC), "Implementor Async" },
  { CLFF_BITS(FDDI_FC_NRT),       "Nonrestricted Token" },
  { CLFF_BITS(FDDI_FC_MAC),       "MAC" },
  { CLFF_BITS(FDDI_FC_LLC_SYNC),  "Sync LLC" },
  { CLFF_BITS(FDDI_FC_IMP_SYNC),  "Implementor Sync" },
  { 0,                            NULL }
};

static const value_string smt_subtype_vals[] = {
  { ZZZZ_BITS(FDDI_FC_SMT_INFO), "Info" },
  { ZZZZ_BITS(FDDI_FC_SMT_NSA),  "Next Station Address" },
  { 0,                           NULL }
};

static const value_string mac_subtype_vals[] = {
  { ZZZZ_BITS(FDDI_FC_MAC_BEACON), "Beacon" },
  { ZZZZ_BITS(FDDI_FC_MAC_CLAIM),  "Claim" },
  { 0,                             NULL }
};

#define FDDI_HEADER_SIZE       13

/* field positions */

#define FDDI_P_FC               0
#define FDDI_P_DHOST            1
#define FDDI_P_SHOST            7

static dissector_handle_t llc_handle;
static dissector_handle_t data_handle;

static void
swap_mac_addr(guint8 *swapped_addr, tvbuff_t *tvb, gint offset)
{
  int i;

  for (i = 0; i < 6; i++) {
    swapped_addr[i] = BIT_SWAP(tvb_get_guint8(tvb, offset+i));
  }
}


void
capture_fddi(const guchar *pd, int len, packet_counts *ld)
{
  int offset = 0, fc;

  if (!BYTES_ARE_IN_FRAME(0, len, FDDI_HEADER_SIZE + FDDI_PADDING)) {
    ld->other++;
    return;
  }
  offset = FDDI_PADDING + FDDI_HEADER_SIZE;

  fc = (int) pd[FDDI_P_FC+FDDI_PADDING];

  switch (fc) {

    /* From now, only 802.2 SNAP (Async. LCC frame) is supported */

    case FDDI_FC_LLC_ASYNC + 0  :
    case FDDI_FC_LLC_ASYNC + 1  :
    case FDDI_FC_LLC_ASYNC + 2  :
    case FDDI_FC_LLC_ASYNC + 3  :
    case FDDI_FC_LLC_ASYNC + 4  :
    case FDDI_FC_LLC_ASYNC + 5  :
    case FDDI_FC_LLC_ASYNC + 6  :
    case FDDI_FC_LLC_ASYNC + 7  :
    case FDDI_FC_LLC_ASYNC + 8  :
    case FDDI_FC_LLC_ASYNC + 9  :
    case FDDI_FC_LLC_ASYNC + 10 :
    case FDDI_FC_LLC_ASYNC + 11 :
    case FDDI_FC_LLC_ASYNC + 12 :
    case FDDI_FC_LLC_ASYNC + 13 :
    case FDDI_FC_LLC_ASYNC + 14 :
    case FDDI_FC_LLC_ASYNC + 15 :
      capture_llc(pd, offset, len, ld);
      return;
    default :
      ld->other++;
      return;

  } /* fc */

} /* capture_fddi */

static const gchar *
fddifc_to_str(int fc)
{
  static gchar strbuf[128+1];

  switch (fc) {

  case FDDI_FC_VOID:                    /* Void frame */
    return "Void frame";

  case FDDI_FC_NRT:                     /* Nonrestricted token */
    return "Nonrestricted token";

  case FDDI_FC_RT:                      /* Restricted token */
    return "Restricted token";

  case FDDI_FC_SMT_INFO:                /* SMT Info */
    return "SMT info";

  case FDDI_FC_SMT_NSA:                 /* SMT Next station adrs */
    return "SMT Next station address";

  case FDDI_FC_MAC_BEACON:              /* MAC Beacon frame */
    return "MAC beacon";

  case FDDI_FC_MAC_CLAIM:               /* MAC Claim frame */
    return "MAC claim token";

  default:
    switch (fc & FDDI_FC_CLFF) {

    case FDDI_FC_MAC:
      g_snprintf(strbuf, sizeof(strbuf), "MAC frame, control %x", fc & FDDI_FC_ZZZZ);
      return strbuf;

    case FDDI_FC_SMT:
      g_snprintf(strbuf, sizeof(strbuf), "SMT frame, control %x", fc & FDDI_FC_ZZZZ);
      return strbuf;

    case FDDI_FC_LLC_ASYNC:
      if (fc & FDDI_FC_ASYNC_R)
        g_snprintf(strbuf, sizeof(strbuf), "Async LLC frame, control %x", fc & FDDI_FC_ZZZZ);
      else
        g_snprintf(strbuf, sizeof(strbuf), "Async LLC frame, priority %d",
                        fc & FDDI_FC_ASYNC_PRI);
      return strbuf;

    case FDDI_FC_LLC_SYNC:
      if (fc & FDDI_FC_ZZZZ) {
        g_snprintf(strbuf, sizeof(strbuf), "Sync LLC frame, control %x", fc & FDDI_FC_ZZZZ);
        return strbuf;
      } else
        return "Sync LLC frame";

    case FDDI_FC_IMP_ASYNC:
      g_snprintf(strbuf, sizeof(strbuf), "Implementor async frame, control %x",
                        fc & FDDI_FC_ZZZZ);
      return strbuf;

    case FDDI_FC_IMP_SYNC:
      g_snprintf(strbuf, sizeof(strbuf), "Implementor sync frame, control %x",
                        fc & FDDI_FC_ZZZZ);
      return strbuf;

    default:
      return "Unknown frame type";
    }
  }
}


static void
dissect_fddi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
             gboolean bitswapped)
{
  proto_tree      *fh_tree     = NULL;
  proto_item      *ti, *hidden_item;
  const gchar     *fc_str;
  proto_tree      *fc_tree;
  static guchar    src[6], dst[6]; /* has to be static due to SET_ADDRESS */
  guchar           src_swapped[6], dst_swapped[6];
  tvbuff_t        *next_tvb;
  static fddi_hdr  fddihdrs[4];
  static int       fddihdr_num = 0;
  fddi_hdr        *fddihdr;

  fddihdr_num++;
  if (fddihdr_num >= 4) {
     fddihdr_num = 0;
  }
  fddihdr = &fddihdrs[fddihdr_num];

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "FDDI");

  fddihdr->fc = tvb_get_guint8(tvb, FDDI_P_FC + FDDI_PADDING);
  fc_str = fddifc_to_str(fddihdr->fc);

  col_add_str(pinfo->cinfo, COL_INFO, fc_str);

  if (tree) {
    ti = proto_tree_add_protocol_format(tree, proto_fddi, tvb, 0, FDDI_HEADER_SIZE+FDDI_PADDING,
                                        "Fiber Distributed Data Interface, %s", fc_str);
    fh_tree = proto_item_add_subtree(ti, ett_fddi);
    ti = proto_tree_add_uint_format_value(fh_tree, hf_fddi_fc, tvb, FDDI_P_FC + FDDI_PADDING, 1, fddihdr->fc,
        "0x%02x (%s)", fddihdr->fc, fc_str);
    fc_tree = proto_item_add_subtree(ti, ett_fddi_fc);
    proto_tree_add_uint(fc_tree, hf_fddi_fc_clf, tvb, FDDI_P_FC + FDDI_PADDING, 1, fddihdr->fc);
    switch ((fddihdr->fc) & FDDI_FC_CLFF) {

    case FDDI_FC_SMT:
      proto_tree_add_uint(fc_tree, hf_fddi_fc_smt_subtype, tvb, FDDI_P_FC + FDDI_PADDING, 1, fddihdr->fc);
      break;

    case FDDI_FC_MAC:
      if (fddihdr->fc != FDDI_FC_RT)
        proto_tree_add_uint(fc_tree, hf_fddi_fc_mac_subtype, tvb, FDDI_P_FC + FDDI_PADDING, 1, fddihdr->fc);
      break;

    case FDDI_FC_LLC_ASYNC:
      if (!((fddihdr->fc) & FDDI_FC_ASYNC_R))
        proto_tree_add_uint(fc_tree, hf_fddi_fc_prio, tvb, FDDI_P_FC + FDDI_PADDING, 1, fddihdr->fc);
      break;
    }
  }

  /* Extract the destination address, possibly bit-swapping it. */
  if (bitswapped)
    swap_mac_addr(dst, tvb, FDDI_P_DHOST + FDDI_PADDING);
  else
    tvb_memcpy(tvb, dst, FDDI_P_DHOST + FDDI_PADDING, sizeof(dst));
  swap_mac_addr(dst_swapped, tvb, FDDI_P_DHOST + FDDI_PADDING);

  /* XXX - copy them to some buffer associated with "pi", rather than
     just making "dst" static? */
  SET_ADDRESS(&pinfo->dl_dst, AT_ETHER, 6, &dst[0]);
  SET_ADDRESS(&pinfo->dst, AT_ETHER, 6, &dst[0]);
  SET_ADDRESS(&fddihdr->dst, AT_ETHER, 6, &dst[0]);

  if (fh_tree) {
    proto_tree_add_ether(fh_tree, hf_fddi_dst, tvb, FDDI_P_DHOST + FDDI_PADDING, 6, dst);
    hidden_item = proto_tree_add_ether(fh_tree, hf_fddi_addr, tvb, FDDI_P_DHOST + FDDI_PADDING, 6, dst);
    PROTO_ITEM_SET_HIDDEN(hidden_item);

    /* hide some bit-swapped mac address fields in the proto_tree, just in case */
    hidden_item = proto_tree_add_ether(fh_tree, hf_fddi_dst, tvb, FDDI_P_DHOST + FDDI_PADDING, 6, dst_swapped);
    PROTO_ITEM_SET_HIDDEN(hidden_item);
    hidden_item = proto_tree_add_ether(fh_tree, hf_fddi_addr, tvb, FDDI_P_DHOST + FDDI_PADDING, 6, dst_swapped);
    PROTO_ITEM_SET_HIDDEN(hidden_item);
  }

  /* Extract the source address, possibly bit-swapping it. */
  if (bitswapped)
    swap_mac_addr(src, tvb, FDDI_P_SHOST + FDDI_PADDING);
  else
    tvb_memcpy(tvb, src, FDDI_P_SHOST + FDDI_PADDING, sizeof(src));
  swap_mac_addr(src_swapped, tvb, FDDI_P_SHOST + FDDI_PADDING);

  /* XXX - copy them to some buffer associated with "pi", rather than
     just making "src" static? */
  SET_ADDRESS(&pinfo->dl_src, AT_ETHER, 6, &src[0]);
  SET_ADDRESS(&pinfo->src, AT_ETHER, 6, &src[0]);
  SET_ADDRESS(&fddihdr->src, AT_ETHER, 6, &src[0]);

  if (fh_tree) {
    proto_tree_add_ether(fh_tree, hf_fddi_src, tvb, FDDI_P_SHOST + FDDI_PADDING, 6, src);
    hidden_item = proto_tree_add_ether(fh_tree, hf_fddi_addr, tvb, FDDI_P_SHOST + FDDI_PADDING, 6, src);
    PROTO_ITEM_SET_HIDDEN(hidden_item);

    /* hide some bit-swapped mac address fields in the proto_tree, just in case */
    hidden_item = proto_tree_add_ether(fh_tree, hf_fddi_src, tvb, FDDI_P_SHOST + FDDI_PADDING, 6, src_swapped);
    PROTO_ITEM_SET_HIDDEN(hidden_item);
    hidden_item = proto_tree_add_ether(fh_tree, hf_fddi_addr, tvb, FDDI_P_SHOST + FDDI_PADDING, 6, src_swapped);
    PROTO_ITEM_SET_HIDDEN(hidden_item);
  }

  next_tvb = tvb_new_subset_remaining(tvb, FDDI_HEADER_SIZE + FDDI_PADDING);


  tap_queue_packet(fddi_tap, pinfo, fddihdr);

  switch (fddihdr->fc) {

    /* From now, only 802.2 SNAP (Async. LCC frame) is supported */

    case FDDI_FC_LLC_ASYNC + 0  :
    case FDDI_FC_LLC_ASYNC + 1  :
    case FDDI_FC_LLC_ASYNC + 2  :
    case FDDI_FC_LLC_ASYNC + 3  :
    case FDDI_FC_LLC_ASYNC + 4  :
    case FDDI_FC_LLC_ASYNC + 5  :
    case FDDI_FC_LLC_ASYNC + 6  :
    case FDDI_FC_LLC_ASYNC + 7  :
    case FDDI_FC_LLC_ASYNC + 8  :
    case FDDI_FC_LLC_ASYNC + 9  :
    case FDDI_FC_LLC_ASYNC + 10 :
    case FDDI_FC_LLC_ASYNC + 11 :
    case FDDI_FC_LLC_ASYNC + 12 :
    case FDDI_FC_LLC_ASYNC + 13 :
    case FDDI_FC_LLC_ASYNC + 14 :
    case FDDI_FC_LLC_ASYNC + 15 :
      call_dissector(llc_handle, next_tvb, pinfo, tree);
      return;

    default :
      call_dissector(data_handle,next_tvb, pinfo, tree);
      return;

  } /* fc */
} /* dissect_fddi */


static void
dissect_fddi_bitswapped(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  dissect_fddi(tvb, pinfo, tree, TRUE);
}

static void
dissect_fddi_not_bitswapped(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  dissect_fddi(tvb, pinfo, tree, FALSE);
}

void
proto_register_fddi(void)
{
  static hf_register_info hf[] = {

    /*
     * XXX - we want this guy to have his own private formatting
     * routine, using "fc_to_str()"; if "fc_to_str()" returns
     * NULL, just show the hex value, else show the string.
     */
    { &hf_fddi_fc,
      { "Frame Control", "fddi.fc", FT_UINT8, BASE_HEX, NULL, 0x0,
        NULL, HFILL }},

    { &hf_fddi_fc_clf,
      { "Class/Length/Format", "fddi.fc.clf", FT_UINT8, BASE_HEX, VALS(clf_vals), FDDI_FC_CLFF,
        NULL, HFILL }},

    { &hf_fddi_fc_prio,
      { "Priority", "fddi.fc.prio", FT_UINT8, BASE_DEC, NULL, FDDI_FC_ASYNC_PRI,
        NULL, HFILL }},

    { &hf_fddi_fc_smt_subtype,
      { "SMT Subtype", "fddi.fc.smt_subtype", FT_UINT8, BASE_DEC, VALS(smt_subtype_vals), FDDI_FC_ZZZZ,
        NULL, HFILL }},

    { &hf_fddi_fc_mac_subtype,
      { "MAC Subtype", "fddi.fc.mac_subtype", FT_UINT8, BASE_DEC, VALS(mac_subtype_vals), FDDI_FC_ZZZZ,
        NULL, HFILL }},

    { &hf_fddi_dst,
      { "Destination", "fddi.dst", FT_ETHER, BASE_NONE, NULL, 0x0,
        "Destination Hardware Address", HFILL }},

    { &hf_fddi_src,
      { "Source", "fddi.src", FT_ETHER, BASE_NONE, NULL, 0x0,
        NULL, HFILL }},

    { &hf_fddi_addr,
      { "Source or Destination Address", "fddi.addr", FT_ETHER, BASE_NONE, NULL, 0x0,
        "Source or Destination Hardware Address", HFILL }},

  };
  static gint *ett[] = {
    &ett_fddi,
    &ett_fddi_fc,
  };

  module_t *fddi_module;

  proto_fddi = proto_register_protocol("Fiber Distributed Data Interface",
                                       "FDDI", "fddi");
  proto_register_field_array(proto_fddi, hf, array_length(hf));
  proto_register_subtree_array(ett, array_length(ett));

  /*
   * Called from various dissectors for encapsulated FDDI frames.
   * We assume the MAC addresses in them aren't bitswapped.
   */
  register_dissector("fddi", dissect_fddi_not_bitswapped, proto_fddi);

  fddi_module = prefs_register_protocol(proto_fddi, NULL);
  prefs_register_bool_preference(fddi_module, "padding",
                                 "Add 3-byte padding to all FDDI packets",
                                 "Whether the FDDI dissector should add 3-byte padding to all "
                                 "captured FDDI packets (useful with e.g. Tru64 UNIX tcpdump)",
                                 &fddi_padding);

  fddi_tap = register_tap("fddi");
}

void
proto_reg_handoff_fddi(void)
{
  dissector_handle_t fddi_handle, fddi_bitswapped_handle;

  /*
   * Get a handle for the LLC dissector.
   */
  llc_handle = find_dissector("llc");
  data_handle = find_dissector("data");

  fddi_handle = find_dissector("fddi");
  dissector_add_uint("wtap_encap", WTAP_ENCAP_FDDI, fddi_handle);
  fddi_bitswapped_handle =
    create_dissector_handle(dissect_fddi_bitswapped, proto_fddi);
  dissector_add_uint("wtap_encap", WTAP_ENCAP_FDDI_BITSWAPPED,
                     fddi_bitswapped_handle);
}
