/* packet-raw.c

 * Routines for raw packet disassembly

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 *

 * This file created and by Mike Hall <mlh@io.com>

 * Copyright 1998

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/capture_dissectors.h>

#include "packet-ip.h"

#include "packet-ppp.h"

void proto_register_raw(void);

void proto_reg_handoff_raw(void);

static int proto_raw;

static int ett_raw;

static const unsigned char zeroes[10] = {0,0,0,0,0,0,0,0,0,0};

static dissector_handle_t raw_handle;

static dissector_handle_t ip_handle;

static dissector_handle_t ipv4_handle;

static dissector_handle_t ipv6_handle;

static dissector_handle_t ppp_hdlc_handle;

static capture_dissector_handle_t ip_cap_handle;

static capture_dissector_handle_t ipv6_cap_handle;

static capture_dissector_handle_t ppp_hdlc_cap_handle;

static bool

capture_raw(const unsigned char *pd, int offset _U_, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header _U_)

{

  /* So far, the only time we get raw connection types are with Linux and

   * Irix PPP connections.  We can't tell what type of data is coming down

   * the line, so our safest bet is IP. - GCC

   */

  /* Currently, the Linux 2.1.xxx PPP driver passes back some of the header

   * sometimes.  This check should be removed when 2.2 is out.

   */

  if (BYTES_ARE_IN_FRAME(0,len,2) && pd[0] == 0xff && pd[1] == 0x03) {

    return call_capture_dissector(ppp_hdlc_cap_handle, pd, 0, len, cpinfo, pseudo_header);

  }

  /* The Linux ISDN driver sends a fake MAC address before the PPP header

   * on its ippp interfaces... */

  else if (BYTES_ARE_IN_FRAME(0,len,8) && pd[6] == 0xff && pd[7] == 0x03) {

    return call_capture_dissector(ppp_hdlc_cap_handle, pd, 6, len, cpinfo, pseudo_header);

  }

  /* ...except when it just puts out one byte before the PPP header... */

  else if (BYTES_ARE_IN_FRAME(0,len,3) && pd[1] == 0xff && pd[2] == 0x03) {

    return call_capture_dissector(ppp_hdlc_cap_handle, pd, 1, len, cpinfo, pseudo_header);

  }

  /* ...and if the connection is currently down, it sends 10 bytes of zeroes

   * instead of a fake MAC address and PPP header. */

  else if (BYTES_ARE_IN_FRAME(0,len,10) && memcmp(pd, zeroes, 10) == 0) {

    return call_capture_dissector(ip_cap_handle, pd, 10, len, cpinfo, pseudo_header);

  }

  else {

    /*

     * OK, is this IPv4 or IPv6?

     */

    if (BYTES_ARE_IN_FRAME(0,len,1)) {

      switch (pd[0] & 0xF0) {

      case 0x40:

        /* IPv4 */

        return call_capture_dissector(ip_cap_handle, pd, 0, len, cpinfo, pseudo_header);

#if 0

      case 0x60:

        /* IPv6 */

        return call_capture_dissector(ipv6_cap_handle, pd, 0, len, cpinfo, pseudo_header);

#endif

      }

    }

  }

  return false;

}

static int

dissect_raw(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

  tvbuff_t      *next_tvb;

  /* load the top pane info. This should be overwritten by

     the next protocol in the stack */

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "N/A");

  col_set_str(pinfo->cinfo, COL_INFO, "Raw packet data");

  /* populate a tree in the second pane with the status of the link

     layer (ie none) */

  proto_tree_add_item(tree, proto_raw, tvb, 0, tvb_captured_length(tvb), ENC_NA);

  /* So far, the only time we get raw connection types are with Linux and

   * Irix PPP connections.  We can't tell what type of data is coming down

   * the line, so our safest bet is IP. - GCC

   */

  /* Currently, the Linux 2.1.xxx PPP driver passes back some of the header

   * sometimes.  This check should be removed when 2.2 is out.

   */

  if (tvb_get_ntohs(tvb, 0) == 0xff03) {

    call_dissector(ppp_hdlc_handle, tvb, pinfo, tree);

  }

  /* The Linux ISDN driver sends a fake MAC address before the PPP header

   * on its ippp interfaces... */

  else if (tvb_get_ntohs(tvb, 6) == 0xff03) {

    next_tvb = tvb_new_subset_remaining(tvb, 6);

    call_dissector(ppp_hdlc_handle, next_tvb, pinfo, tree);

  }

  /* ...except when it just puts out one byte before the PPP header... */

  else if (tvb_get_ntohs(tvb, 1) == 0xff03) {

    next_tvb = tvb_new_subset_remaining(tvb, 1);

    call_dissector(ppp_hdlc_handle, next_tvb, pinfo, tree);

  }

  /* ...and if the connection is currently down, it sends 10 bytes of zeroes

   * instead of a fake MAC address and PPP header.

   *

   * XXX - in at least one capture, I've seen 10 bytes of non-zero

   * values before the initial 0x45 of an IP packet without options.

   * However, just skipping the first 10 bytes if there's a 0x4x

   * byte after it breaks the parsing of some other captures. */

  else if (tvb_memeql(tvb, 0, zeroes,10) == 0) {

    next_tvb = tvb_new_subset_remaining(tvb, 10);

    call_dissector(ip_handle, next_tvb, pinfo, tree);

  }

  else {

    /*

     * OK, is this IPv4 or IPv6?

     */

    switch (tvb_get_uint8(tvb, 0) & 0xF0) {

    case 0x40:

      /*

       * IPv4.

       *

       * Create a new tvbuff, so that if the dissector sets the length

       * (e.g., because the packet has extra stuff after the datagram),

       * the top-level tvbuff isn't modified and shows all the data.

       */

      next_tvb = tvb_new_subset_remaining(tvb, 0);

      call_dissector(ipv4_handle, next_tvb, pinfo, tree);

      break;

    case 0x60:

      /*

       * IPv6.

       *

       * Create a new tvbuff, so that if the dissector sets the length

       * (e.g., because the packet has extra stuff after the datagram),

       * the top-level tvbuff isn't modified and shows all the data.

       */

      next_tvb = tvb_new_subset_remaining(tvb, 0);

      call_dissector(ipv6_handle, next_tvb, pinfo, tree);

      break;

    default:

      /* None of the above. */

      call_data_dissector(tvb, pinfo, tree);

      break;

    }

  }

  return tvb_captured_length(tvb);

}

static int

dissect_raw_ip4(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

  tvbuff_t      *next_tvb;

  /* load the top pane info. This should be overwritten by

     the next protocol in the stack */

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "N/A");

  col_set_str(pinfo->cinfo, COL_INFO, "Raw packet data");

  /* populate a tree in the second pane with the status of the link

     layer (ie none) */

  proto_tree_add_item(tree, proto_raw, tvb, 0, tvb_captured_length(tvb), ENC_NA);

  /*

   * OK, hand this to the IPv4 dissector.

   *

   * Create a new tvbuff, so that if the dissector sets the length

   * (e.g., because the packet has extra stuff after the datagram),

   * the top-level tvbuff isn't modified and shows all the data.

   */

  next_tvb = tvb_new_subset_remaining(tvb, 0);

  call_dissector(ipv4_handle, next_tvb, pinfo, tree);

  return tvb_captured_length(tvb);

}

static int

dissect_raw_ip6(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

  tvbuff_t      *next_tvb;

  /* load the top pane info. This should be overwritten by

     the next protocol in the stack */

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "N/A");

  col_set_str(pinfo->cinfo, COL_INFO, "Raw packet data");

  /* populate a tree in the second pane with the status of the link

     layer (ie none) */

  proto_tree_add_item(tree, proto_raw, tvb, 0, tvb_captured_length(tvb), ENC_NA);

  /*

   * OK, hand this to the IPv6 dissector.

   *

   * Create a new tvbuff, so that if the dissector sets the length

   * (e.g., because the packet has extra stuff after the datagram),

   * the top-level tvbuff isn't modified and shows all the data.

   */

  next_tvb = tvb_new_subset_remaining(tvb, 0);

  call_dissector(ipv6_handle, next_tvb, pinfo, tree);

  return tvb_captured_length(tvb);

}

void

proto_register_raw(void)

{

  static int *ett[] = {

    &ett_raw,

  };

  proto_raw = proto_register_protocol("Raw packet data", "Raw", "raw");

  proto_register_subtree_array(ett, array_length(ett));

  raw_handle = register_dissector("raw_ip", dissect_raw, proto_raw);

}

void

proto_reg_handoff_raw(void)

{

  dissector_handle_t raw_ip4_handle;

  dissector_handle_t raw_ip6_handle;

  capture_dissector_handle_t raw_cap_handle;

  /*

   * Get handles for the IPv{4,6}, IPv4, IPv6, undissected-data, and

   * PPP-in-HDLC-like-framing dissectors.

   */

  ip_handle = find_dissector_add_dependency("ip", proto_raw);

  ipv4_handle = find_dissector_add_dependency("ipv4", proto_raw);

  ipv6_handle = find_dissector_add_dependency("ipv6", proto_raw);

  ppp_hdlc_handle = find_dissector_add_dependency("ppp_hdlc", proto_raw);

  dissector_add_uint("wtap_encap", WTAP_ENCAP_RAW_IP, raw_handle);

  raw_ip4_handle = create_dissector_handle(dissect_raw_ip4, proto_raw);

  dissector_add_uint("wtap_encap", WTAP_ENCAP_RAW_IP4, raw_ip4_handle);

  raw_ip6_handle = create_dissector_handle(dissect_raw_ip6, proto_raw);

  dissector_add_uint("wtap_encap", WTAP_ENCAP_RAW_IP6, raw_ip6_handle);

  raw_cap_handle = create_capture_dissector_handle(capture_raw, proto_raw);

  capture_dissector_add_uint("wtap_encap", WTAP_ENCAP_RAW_IP, raw_cap_handle);

  ip_cap_handle = find_capture_dissector("ip");

  ipv6_cap_handle = find_capture_dissector("ipv6");

  ppp_hdlc_cap_handle = find_capture_dissector("ppp_hdlc");

}

/*

 * Editor modelines

 *

 * Local Variables:

 * c-basic-offset: 2

 * tab-width: 8

 * indent-tabs-mode: nil

 * End:

 *

 * ex: set shiftwidth=2 tabstop=8 expandtab:

 * :indentSize=2:tabSize=8:noTabs=true:

 */