/* packet-erldp.c

 * Erlang Distribution Protocol

 * http://www.erlang.org/doc/apps/erts/erl_dist_protocol.html

 *

 * 2010  Tomas Kukosa

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

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

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/expert.h>

#include <epan/tfs.h>

#include <epan/reassemble.h>

#include "packet-tcp.h"

#include "packet-epmd.h"

#define ERL_PASS_THROUGH      'p'

#define VERSION_MAGIC 131   /* 130 in erlang 4.2 */

#define SMALL_INTEGER_EXT   'a'

#define INTEGER_EXT         'b'

#define FLOAT_EXT           'c'

#define ATOM_EXT            'd'

#define ATOM_UTF8_EXT       'v'

#define SMALL_ATOM_EXT      's'

#define SMALL_ATOM_UTF8_EXT 'w'

#define REFERENCE_EXT       'e'

#define NEW_REFERENCE_EXT   'r'

#define NEWER_REFERENCE_EXT 'Z'

#define PORT_EXT            'f'

#define NEW_PORT_EXT        'Y'

#define V4_PORT_EXT         'x'

#define NEW_FLOAT_EXT       'F'

#define PID_EXT             'g'

#define NEW_PID_EXT         'X'

#define SMALL_TUPLE_EXT     'h'

#define LARGE_TUPLE_EXT     'i'

#define NIL_EXT             'j'

#define STRING_EXT          'k'

#define LIST_EXT            'l'

#define BINARY_EXT          'm'

#define BIT_BINARY_EXT      'M'

#define SMALL_BIG_EXT       'n'

#define LARGE_BIG_EXT       'o'

#define NEW_FUN_EXT         'p'

#define EXPORT_EXT          'q'

#define FUN_EXT             'u'

#define MAP_EXT             't'

#define LOCAL_EXT           'y'

#define RECORD_EXT          'C'

#define DIST_HEADER         'D'

#define DIST_FRAG_HEADER    'E'

#define DIST_FRAG_CONT      'F'

#define ATOM_CACHE_REF      'R'

#define COMPRESSED          'P'

#define DOP_ALTACT_SIG_SEND 37

#define ALTACT_SIG_FLG_PRIO   0x01

#define ALTACT_SIG_FLG_TOKEN  0x02

#define ALTACT_SIG_FLG_ALIAS  0x04

#define ALTACT_SIG_FLG_NAME   0x08

#define ALTACT_SIG_FLG_EXIT   0x10

void proto_register_erldp(void);

void proto_reg_handoff_erldp(void);

static const value_string etf_tag_vals[] = {

  { SMALL_INTEGER_EXT   , "SMALL_INTEGER_EXT" },

  { INTEGER_EXT         , "INTEGER_EXT" },

  { FLOAT_EXT           , "FLOAT_EXT" },

  { ATOM_EXT            , "ATOM_EXT" },

  { ATOM_UTF8_EXT       , "ATOM_UTF8_EXT" },

  { SMALL_ATOM_EXT      , "SMALL_ATOM_EXT" },

  { SMALL_ATOM_UTF8_EXT , "SMALL_ATOM_UTF8_EXT" },

  { REFERENCE_EXT       , "REFERENCE_EXT" },

  { NEW_REFERENCE_EXT   , "NEW_REFERENCE_EXT" },

  { NEWER_REFERENCE_EXT , "NEWER_REFERENCE_EXT" },

  { PORT_EXT            , "PORT_EXT" },

  { NEW_PORT_EXT        , "NEW_PORT_EXT" },

  { V4_PORT_EXT         , "V4_PORT_EXT" },

  { NEW_FLOAT_EXT       , "NEW_FLOAT_EXT" },

  { PID_EXT             , "PID_EXT" },

  { NEW_PID_EXT         , "NEW_PID_EXT" },

  { SMALL_TUPLE_EXT     , "SMALL_TUPLE_EXT" },

  { LARGE_TUPLE_EXT     , "LARGE_TUPLE_EXT" },

  { NIL_EXT             , "NIL_EXT" },

  { STRING_EXT          , "STRING_EXT" },

  { LIST_EXT            , "LIST_EXT" },

  { BINARY_EXT          , "BINARY_EXT" },

  { BIT_BINARY_EXT      , "BIT_BINARY_EXT" },

  { SMALL_BIG_EXT       , "SMALL_BIG_EXT" },

  { LARGE_BIG_EXT       , "LARGE_BIG_EXT" },

  { NEW_FUN_EXT         , "NEW_FUN_EXT" },

  { EXPORT_EXT          , "EXPORT_EXT" },

  { FUN_EXT             , "FUN_EXT" },

  { MAP_EXT             , "MAP_EXT" },

  { LOCAL_EXT           , "LOCAL_EXT" },

  { RECORD_EXT          , "RECORD_EXT" },

  { DIST_HEADER         , "DIST_HEADER" },

  { DIST_FRAG_HEADER    , "DIST_FRAG_HEADER" },

  { ATOM_CACHE_REF      , "ATOM_CACHE_REF" },

  { COMPRESSED          , "COMPRESSED" },

  {  0, NULL }

};

static const value_string etf_header_tag_vals[] = {

  { DIST_HEADER         , "DIST_HEADER" },

  { DIST_FRAG_HEADER    , "DIST_FRAG_HEADER" },

  { DIST_FRAG_CONT      , "DIST_FRAG_CONT" },

  {  0, NULL }

};

static const value_string erldp_ctlmsg_vals[] = {

  {  1, "LINK" },

  {  2, "SEND" },

  {  3, "EXIT" },

  {  4, "UNLINK" },

  {  5, "NODE_LINK" },

  {  6, "REG_SEND" },

  {  7, "GROUP_LEADER" },

  {  8, "EXIT2" },

  { 12, "SEND_TT" },

  { 13, "EXIT_TT" },

  { 16, "REG_SEND_TT" },

  { 18, "EXIT2_TT" },

  { 19, "MONITOR_P" },

  { 20, "DEMONITOR_P" },

  { 21, "MONITOR_P_EXIT" },

  { 22, "SEND_SENDER" },

  { 23, "SEND_SENDER_TT" },

  { 24, "PAYLOAD_EXIT" },

  { 25, "PAYLOAD_EXIT_TT" },

  { 26, "PAYLOAD_EXIT2" },

  { 27, "PAYLOAD_EXIT2_TT" },

  { 28, "PAYLOAD_MONITOR_P_EXIT" },

  { 29, "SPAWN_REQUEST" },

  { 30, "SPAWN_REQUEST_TT" },

  { 31, "SPAWN_REPLY" },

  { 32, "SPAWN_REPLY_TT" },

  { 33, "ALIAS_SEND" },

  { 34, "ALIAS_SEND_TT" },

  { 35, "UNLINK_ID" },

  { 36, "UNLINK_ID_ACK" },

  { DOP_ALTACT_SIG_SEND, "ALTACT_SIG_SEND" },

  {  0, NULL }

};

/* Initialize the protocol and registered fields */

static int proto_erldp;

static int hf_erldp_length_2;

static int hf_erldp_length_4;

static int hf_etf_version_magic;

static int hf_erldp_tag;

static int hf_erldp_type;

static int hf_erldp_version;

static int hf_erldp_flags_v5;

static int hf_erldp_flags_v6;

static int hf_erldp_flags_published;

static int hf_erldp_flags_atom_cache;

static int hf_erldp_flags_extended_references;

static int hf_erldp_flags_dist_monitor;

static int hf_erldp_flags_fun_tags;

static int hf_erldp_flags_dist_monitor_name;

static int hf_erldp_flags_hidden_atom_cache;

static int hf_erldp_flags_new_fun_tags;

static int hf_erldp_flags_extended_pids_ports;

static int hf_erldp_flags_export_ptr_tag;

static int hf_erldp_flags_bit_binaries;

static int hf_erldp_flags_new_floats;

static int hf_erldp_flags_unicode_io;

static int hf_erldp_flags_dist_hdr_atom_cache;

static int hf_erldp_flags_small_atom_tags;

static int hf_erldp_flags_ets_compressed;

static int hf_erldp_flags_utf8_atoms;

static int hf_erldp_flags_map_tag;

static int hf_erldp_flags_big_creation;

static int hf_erldp_flags_send_sender;

static int hf_erldp_flags_big_seqtrace_labels;

static int hf_erldp_flags_pending_connect;

static int hf_erldp_flags_exit_payload;

static int hf_erldp_flags_fragments;

static int hf_erldp_flags_handshake_23;

static int hf_erldp_flags_unlink_id;

static int hf_erldp_flags_mandatory_25_digest;

static int hf_erldp_flags_reserved;

static int hf_erldp_flags_spawn;

static int hf_erldp_flags_name_me;

static int hf_erldp_flags_v4_nc;

static int hf_erldp_flags_alias;

static int hf_erldp_flags_local_ext;

static int hf_erldp_flags_altact_sig;

static int hf_erldp_flags_native_records;

static int hf_erldp_flags_spare;

static int hf_erldp_flags_high;

static int hf_erldp_flags_high_spawn;

static int hf_erldp_flags_high_name_me;

static int hf_erldp_flags_high_v4_nc;

static int hf_erldp_flags_high_alias;

static int hf_erldp_flags_high_local_ext;

static int hf_erldp_flags_high_altact_sig;

static int hf_erldp_flags_high_native_records;

static int hf_erldp_flags_high_spare;

static int hf_erldp_creation;

static int hf_erldp_challenge;

static int hf_erldp_digest;

static int hf_erldp_nlen;

static int hf_erldp_name;

static int hf_erldp_status;

static int hf_erldp_sequence_id;

static int hf_erldp_fragment_id;

static int hf_erldp_num_atom_cache_refs;

static int hf_erldp_etf_flags;

static int hf_erldp_internal_segment_index;

static int hf_erldp_atom_length;

static int hf_erldp_atom_length2;

static int hf_erldp_atom_text;

static int hf_erldp_string_ext_len;

static int hf_erldp_string_ext;

static int hf_erldp_atom_cache_ref;

static int hf_erldp_small_int_ext;

static int hf_erldp_int_ext;

static int hf_erldp_small_big_ext_len;

static int hf_erldp_large_big_ext_len;

static int hf_erldp_big_ext_int;

static int hf_erldp_big_ext_str;

static int hf_erldp_big_ext_bytes;

static int hf_erldp_float_ext;

static int hf_erldp_new_float_ext;

static int hf_erldp_port_ext_id;

static int hf_erldp_port_ext_v4_id;

static int hf_erldp_port_ext_creation;

static int hf_erldp_pid_ext_id;

static int hf_erldp_pid_ext_serial;

static int hf_erldp_pid_ext_creation;

static int hf_erldp_list_ext_len;

static int hf_erldp_map_ext_len;

static int hf_erldp_binary_ext_len;

static int hf_erldp_binary_ext_bits;

static int hf_erldp_binary_ext;

static int hf_erldp_new_ref_ext_len;

static int hf_erldp_new_ref_ext_creation;

static int hf_erldp_new_ref_ext_id;

static int hf_erldp_fun_ext_num_free;

static int hf_erldp_new_fun_ext_size;

static int hf_erldp_new_fun_ext_arity;

static int hf_erldp_new_fun_ext_uniq;

static int hf_erldp_new_fun_ext_index;

static int hf_erldp_new_fun_ext_num_free;

static int hf_erldp_ref_ext_id;

static int hf_erldp_local_ext_hash;

static int hf_erldp_local_ext_data;

static int hf_erldp_undecoded;

static int hf_erldp_record_ext_num_fields;

static int hf_erldp_record_ext_flags;

static int hf_erldp_record_ext_flags_exported;

static int hf_erldp_record_ext_flags_reserved;

static int hf_erldp_altact_flags;

static int hf_erldp_altact_flags_prio;

static int hf_erldp_altact_flags_token;

static int hf_erldp_altact_flags_alias;

static int hf_erldp_altact_flags_name;

static int hf_erldp_altact_flags_exit;

static int hf_etf_tag;

static int hf_etf_dist_header_tag;

static int hf_etf_dist_header_new_cache;

static int hf_etf_dist_header_segment_index;

static int hf_etf_dist_header_long_atoms;

static int hf_etf_arity4;

static int hf_etf_arity;

static int hf_etf_fragments;

static int hf_etf_fragment;

static int hf_etf_fragment_overlap;

static int hf_etf_fragment_overlap_conflicts;

static int hf_etf_fragment_multiple_tails;

static int hf_etf_fragment_too_long_fragment;

static int hf_etf_fragment_error;

static int hf_etf_fragment_count;

static int hf_etf_reassembled_in;

static int hf_etf_reassembled_length;

static int hf_etf_reassembled_data;

static reassembly_table erldp_reassembly_table;

/* Initialize the subtree pointers */

static int ett_erldp;

static int ett_erldp_flags;

static int ett_etf;

static int ett_etf_flags;

static int ett_etf_acrs;

static int ett_etf_acr;

static int ett_etf_tmp;

static int ett_etf_altact_flags;

static int ett_etf_record_flags;

static int ett_etf_fragment;

static int ett_etf_fragments;

static expert_field ei_erldp_unknown_tag;

/* Preferences */

static bool erldp_desegment = true;

/* Dissectors */

static dissector_handle_t erldp_handle;

/* Defragmentation */

static const fragment_items etf_frag_items = {

    /* Fragment subtrees */

    &ett_etf_fragment,

    &ett_etf_fragments,

    /* Fragment fields */

    &hf_etf_fragments,

    &hf_etf_fragment,

    &hf_etf_fragment_overlap,

    &hf_etf_fragment_overlap_conflicts,

    &hf_etf_fragment_multiple_tails,

    &hf_etf_fragment_too_long_fragment,

    &hf_etf_fragment_error,

    &hf_etf_fragment_count,

    /* Reassembled in field */

    &hf_etf_reassembled_in,

    /* Reassembled length field */

    &hf_etf_reassembled_length,

    &hf_etf_reassembled_data,

    /* Tag */

    "Message fragments"

};

/*--- External Term Format ---*/

static int dissect_etf_type(const char *label, packet_info *pinfo, tvbuff_t *tvb, int offset, proto_tree *tree);

static int dissect_etf_type_ret_tree(const char *label, packet_info *pinfo, tvbuff_t *tvb, int offset, proto_tree *tree, proto_tree **ret_tree);

static int dissect_etf_pdu_data(packet_info *pinfo, tvbuff_t *tvb, int offset, proto_tree *tree);

static int dissect_etf_dist_header(packet_info *pinfo, tvbuff_t *tvb, int offset, proto_tree *tree) {

  uint32_t num, isi;

  uint8_t flen, flg;

  int flg_offset, acrs_offset, acr_offset;

  uint32_t atom_txt_len;

  bool new_entry, long_atom;

  proto_item *ti_acrs, *ti_acr, *ti_tmp;

  proto_tree *flags_tree, *acrs_tree, *acr_tree;

  const uint8_t *str;

  proto_tree_add_item_ret_uint(tree, hf_erldp_num_atom_cache_refs, tvb, offset, 1, ENC_BIG_ENDIAN, &num);

  offset++;

  if (num == 0)

    return offset;

  flg_offset = offset;

  flen = num / 2 + 1;

  ti_tmp = proto_tree_add_item(tree, hf_erldp_etf_flags, tvb, offset, flen, ENC_NA );

  flags_tree = proto_item_add_subtree(ti_tmp, ett_etf_flags);

  for (unsigned i=0; i<num; i++) {

    flg = tvb_get_uint8(tvb, offset + i / 2);

    proto_tree_add_boolean_format_value(flags_tree, hf_etf_dist_header_new_cache, tvb, offset + i / 2, 1,

                            (flg & (0x08 << 4*(i%2))), "NewCacheEntryFlag[%2d]: %s",

                            i, (flg & (0x08 << 4*(i%2))) ? "SET" : "---");

    proto_tree_add_uint_format(flags_tree, hf_etf_dist_header_segment_index, tvb, offset + i / 2, 1,

                            (flg & (0x07 << 4*(i%2))), "SegmentIndex     [%2d]: %u",

                            i, (flg & (0x07 << 4*(i%2))));

  }

  flg = tvb_get_uint8(tvb, offset + num / 2);

  proto_tree_add_boolean(flags_tree, hf_etf_dist_header_long_atoms, tvb, offset + num / 2, 1, (flg & (0x01 << 4*(num%2))));

  long_atom = flg & (0x01 << 4*(num%2));

  offset += flen;

  acrs_offset = offset;

  acrs_tree = proto_tree_add_subtree(tree, tvb, offset, 0, ett_etf_acrs, &ti_acrs, "AtomCacheRefs");

  for (unsigned i=0; i<num; i++) {

    flg = tvb_get_uint8(tvb, flg_offset + i / 2);

    new_entry = flg & (0x08 << 4*(i%2));

    acr_offset = offset;

    acr_tree = proto_tree_add_subtree_format(acrs_tree, tvb, offset, 0, ett_etf_acr, &ti_acr, "AtomCacheRef[%2d]:", i);

    proto_tree_add_item_ret_uint(acr_tree, hf_erldp_internal_segment_index, tvb, offset, 1, ENC_BIG_ENDIAN, &isi);

    proto_item_append_text(ti_acr, " %3d", isi);

    offset++;

    if (!new_entry)

      continue;

    if (long_atom) {

      proto_tree_add_item_ret_uint(acr_tree, hf_erldp_atom_length2, tvb, offset, 2, ENC_BIG_ENDIAN, &atom_txt_len);

      offset += 2;

    }

    else {

      proto_tree_add_item_ret_uint(acr_tree, hf_erldp_atom_length, tvb, offset, 1, ENC_BIG_ENDIAN, &atom_txt_len);

      offset++;

    }

    proto_tree_add_item_ret_string(acr_tree, hf_erldp_atom_text, tvb, offset, atom_txt_len, ENC_NA|ENC_ASCII, pinfo->pool, &str);

    proto_item_append_text(ti_acr, " - '%s'", str);

    offset += atom_txt_len;

    proto_item_set_len(ti_acr, offset - acr_offset);

  }

  proto_item_set_len(ti_acrs, offset - acrs_offset);

  return offset;

}

// NOLINTNEXTLINE(misc-no-recursion)

static int dissect_etf_tuple_content(bool large, packet_info *pinfo, tvbuff_t *tvb, int offset, proto_tree *tree, const char **value_str _U_) {

  uint32_t arity, i;

  if (large) {

    proto_tree_add_item_ret_uint(tree, hf_etf_arity4, tvb, offset, 4, ENC_BIG_ENDIAN, &arity);

    offset += 4;

  } else {

    proto_tree_add_item_ret_uint(tree, hf_etf_arity, tvb, offset, 1, ENC_BIG_ENDIAN, &arity);

    offset++;

  }

  for (i=0; i<arity; i++) {

    offset = dissect_etf_type(NULL, pinfo, tvb, offset, tree);

  }

  return offset;

}

static int dissect_etf_big_ext(tvbuff_t *tvb, packet_info *pinfo, int offset, uint32_t len, proto_tree *tree, const char **value_str) {

      uint8_t sign;

      int32_t i;

      sign = tvb_get_uint8(tvb, offset);

      offset += 1;

      if (len <= 8) {

        uint64_t big_val = 0;

        switch (len) {

        case 1: big_val = tvb_get_uint8(tvb, offset); break;

        case 2: big_val = tvb_get_letohs(tvb, offset); break;

        case 3: big_val = tvb_get_letoh24(tvb, offset); break;

        case 4: big_val = tvb_get_letohl(tvb, offset); break;

        case 5: big_val = tvb_get_letoh40(tvb, offset); break;

        case 6: big_val = tvb_get_letoh48(tvb, offset); break;

        case 7: big_val = tvb_get_letoh56(tvb, offset); break;

        case 8: big_val = tvb_get_letoh64(tvb, offset); break;

        }

        proto_tree_add_uint64_format_value(tree, hf_erldp_big_ext_int, tvb, offset, len,

                                           big_val, "%s%" PRIu64, sign ? "-"  : "", big_val);

        if (value_str)

          *value_str = wmem_strdup_printf(pinfo->pool, "%s%" PRIu64,

                                          sign ? "-"  : "", big_val);

      } else if (len < 64) {

        wmem_strbuf_t *strbuf = wmem_strbuf_new_sized(pinfo->pool, len*1+3+1);

        wmem_strbuf_append(strbuf, "0x");

        for (i = len - 1; i >= 0; i--) {

          wmem_strbuf_append_printf(strbuf, "%02x", tvb_get_uint8(tvb, offset + i));

        }

        char *buf = wmem_strbuf_finalize(strbuf);

        proto_tree_add_string_format_value(tree, hf_erldp_big_ext_str, tvb, offset, len, buf, "%s", buf);

        if (value_str)

          *value_str = buf;

      } else {

        /* len is from the packet: do not let a huge value wrap offset */

        tvb_ensure_bytes_exist64(tvb, offset, len);

        proto_tree_add_item(tree, hf_erldp_big_ext_bytes, tvb, offset, len, ENC_NA);

      }

      return offset + len;

}

// NOLINTNEXTLINE(misc-no-recursion)

static int dissect_etf_type_content(uint8_t tag, packet_info *pinfo, tvbuff_t *tvb, int offset, proto_tree *tree, const char **value_str) {

  int32_t int_val;

  uint32_t len, i, uint_val;

  uint32_t id;

  const uint8_t *str_val;

  static int * const record_flags[] = {

    &hf_erldp_record_ext_flags_reserved,

    &hf_erldp_record_ext_flags_exported,

    NULL

  };

  increment_dissection_depth(pinfo);

  switch (tag) {

    case ATOM_CACHE_REF:

      proto_tree_add_item_ret_uint(tree, hf_erldp_atom_cache_ref, tvb, offset, 1, ENC_BIG_ENDIAN, &uint_val);

      offset += 1;

      if (value_str)

        *value_str = wmem_strdup_printf(pinfo->pool, "%d", uint_val);

      break;

    case SMALL_INTEGER_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_small_int_ext, tvb, offset, 1, ENC_BIG_ENDIAN, &uint_val);

      offset += 1;

      if (value_str)

        *value_str = wmem_strdup_printf(pinfo->pool, "%u", uint_val);

      break;

    case INTEGER_EXT:

      proto_tree_add_item_ret_int(tree, hf_erldp_int_ext, tvb, offset, 4, ENC_BIG_ENDIAN, &int_val);

      offset += 4;

      if (value_str)

        *value_str = wmem_strdup_printf(pinfo->pool, "%d", int_val);

      break;

    case SMALL_BIG_EXT: {

      proto_tree_add_item_ret_uint(tree, hf_erldp_small_big_ext_len, tvb, offset, 1, ENC_BIG_ENDIAN, &len);

      offset += 1;

      offset = dissect_etf_big_ext(tvb, pinfo, offset, len, tree, value_str);

      break;

    }

    case LARGE_BIG_EXT: {

      proto_tree_add_item_ret_uint(tree, hf_erldp_large_big_ext_len, tvb, offset, 4, ENC_BIG_ENDIAN, &len);

      offset += 4;

      offset = dissect_etf_big_ext(tvb, pinfo, offset, len, tree, value_str);

      break;

    }

    case FLOAT_EXT:

      proto_tree_add_item_ret_string(tree, hf_erldp_float_ext, tvb, offset, 31, ENC_NA|ENC_UTF_8, pinfo->pool, &str_val);

      offset += 31;

      if (value_str)

        *value_str = (const char *)str_val;

      break;

    case NEW_FLOAT_EXT:

      proto_tree_add_item(tree, hf_erldp_new_float_ext, tvb, offset, 8, ENC_BIG_ENDIAN);

      if (value_str) {

        double   new_float_val = tvb_get_ntohieee_double(tvb, offset);

        *value_str = wmem_strdup_printf(pinfo->pool, "%f", new_float_val);

      }

      offset += 8;

      break;

    case ATOM_UTF8_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_atom_length2, tvb, offset, 2, ENC_BIG_ENDIAN, &len);

      offset += 2;

      proto_tree_add_item_ret_string(tree, hf_erldp_atom_text, tvb, offset, len, ENC_NA|ENC_UTF_8, pinfo->pool, &str_val);

      offset += len;

      if (value_str)

        *value_str = (const char *)str_val;

      break;

    case ATOM_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_atom_length2, tvb, offset, 2, ENC_BIG_ENDIAN, &len);

      offset += 2;

      proto_tree_add_item_ret_string(tree, hf_erldp_atom_text, tvb, offset, len, ENC_NA|ENC_ISO_8859_1, pinfo->pool, &str_val);

      offset += len;

      if (value_str)

        *value_str = (const char *)str_val;

      break;

    case SMALL_ATOM_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_atom_length, tvb, offset, 1, ENC_BIG_ENDIAN, &len);

      offset++;

      proto_tree_add_item_ret_string(tree, hf_erldp_atom_text, tvb, offset, len, ENC_NA|ENC_ISO_8859_1, pinfo->pool, &str_val);

      offset += len;

      if (value_str)

        *value_str = (const char *)str_val;

      break;

    case SMALL_ATOM_UTF8_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_atom_length, tvb, offset, 1, ENC_BIG_ENDIAN, &len);

      offset++;

      proto_tree_add_item_ret_string(tree, hf_erldp_atom_text, tvb, offset, len, ENC_NA|ENC_UTF_8, pinfo->pool, &str_val);

      offset += len;

      if (value_str)

        *value_str = (const char *)str_val;

      break;

    case STRING_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_string_ext_len, tvb, offset, 2, ENC_BIG_ENDIAN, &len);

      offset += 2;

      proto_tree_add_item_ret_string(tree, hf_erldp_string_ext, tvb, offset, len, ENC_NA|ENC_UTF_8, pinfo->pool, &str_val);

      offset += len;

      if (value_str)

        *value_str = (const char *)str_val;

      break;

    case PORT_EXT:

      offset = dissect_etf_type("Node", pinfo, tvb, offset, tree);

      proto_tree_add_item(tree, hf_erldp_port_ext_id, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      proto_tree_add_item(tree, hf_erldp_port_ext_creation, tvb, offset, 1, ENC_BIG_ENDIAN);

      offset++;

      break;

    case NEW_PORT_EXT:

      offset = dissect_etf_type("Node", pinfo, tvb, offset, tree);

      proto_tree_add_item(tree, hf_erldp_port_ext_id, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      proto_tree_add_item(tree, hf_erldp_port_ext_creation, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      break;

    case V4_PORT_EXT:

      offset = dissect_etf_type("Node", pinfo, tvb, offset, tree);

      proto_tree_add_item(tree, hf_erldp_port_ext_v4_id, tvb, offset, 8, ENC_BIG_ENDIAN);

      offset += 8;

      proto_tree_add_item(tree, hf_erldp_port_ext_creation, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      break;

    case PID_EXT:

      offset = dissect_etf_type("Node", pinfo, tvb, offset, tree);

      proto_tree_add_item(tree, hf_erldp_pid_ext_id, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      proto_tree_add_item(tree, hf_erldp_pid_ext_serial, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      proto_tree_add_item(tree, hf_erldp_pid_ext_creation, tvb, offset, 1, ENC_BIG_ENDIAN);

      offset++;

      break;

    case NEW_PID_EXT:

      offset = dissect_etf_type("Node", pinfo, tvb, offset, tree);

      proto_tree_add_item(tree, hf_erldp_pid_ext_id, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      proto_tree_add_item(tree, hf_erldp_pid_ext_serial, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      proto_tree_add_item(tree, hf_erldp_pid_ext_creation, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      break;

    case SMALL_TUPLE_EXT:

      offset = dissect_etf_tuple_content(false, pinfo, tvb, offset, tree, value_str);

      break;

    case LARGE_TUPLE_EXT:

      offset = dissect_etf_tuple_content(true, pinfo, tvb, offset, tree, value_str);

      break;

    case NIL_EXT:

      break;

    case LIST_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_list_ext_len, tvb, offset, 4, ENC_BIG_ENDIAN, &len);

      offset += 4;

      for (i=0; i<len; i++) {

        offset = dissect_etf_type(NULL, pinfo, tvb, offset, tree);

      }

      offset = dissect_etf_type("Tail", pinfo, tvb, offset, tree);

      break;

    case MAP_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_map_ext_len, tvb, offset, 4, ENC_BIG_ENDIAN, &len);

      offset += 4;

      for (i=0; i<len; i++) {

        // key

        offset = dissect_etf_type(NULL, pinfo, tvb, offset, tree);

        // value

        offset = dissect_etf_type(NULL, pinfo, tvb, offset, tree);

      }

      break;

    case BINARY_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_binary_ext_len, tvb, offset, 4, ENC_BIG_ENDIAN, &len);

      offset += 4;

      tvb_ensure_bytes_exist64(tvb, offset, len);

      proto_tree_add_item(tree, hf_erldp_binary_ext, tvb, offset, len, ENC_NA);

      offset += len;

      break;

    case BIT_BINARY_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_binary_ext_len, tvb, offset, 4, ENC_BIG_ENDIAN, &len);

      offset += 4;

      proto_tree_add_item(tree, hf_erldp_binary_ext_bits, tvb, offset, 1, ENC_BIG_ENDIAN);

      offset++;

      tvb_ensure_bytes_exist64(tvb, offset, len);

      proto_tree_add_item(tree, hf_erldp_binary_ext, tvb, offset, len, ENC_NA);

      offset += len;

      break;

    case REFERENCE_EXT:

      offset = dissect_etf_type("Node", pinfo, tvb, offset, tree);

      proto_tree_add_item(tree, hf_erldp_ref_ext_id, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      proto_tree_add_item(tree, hf_erldp_new_ref_ext_creation, tvb, offset, 1, ENC_BIG_ENDIAN);

      offset++;

      break;

    case NEW_REFERENCE_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_new_ref_ext_len, tvb, offset, 2, ENC_BIG_ENDIAN, &len);

      offset += 2;

      offset = dissect_etf_type("Node", pinfo, tvb, offset, tree);

      proto_tree_add_item(tree, hf_erldp_new_ref_ext_creation, tvb, offset, 1, ENC_BIG_ENDIAN);

      offset++;

      for (i=0; i<len; i++) {

        id = tvb_get_ntohl(tvb, offset);

        proto_tree_add_uint_format(tree, hf_erldp_new_ref_ext_id, tvb, offset, 4,

                            id, "ID[%d]: 0x%08X", i, id);

        offset += 4;

      }

      break;

    case NEWER_REFERENCE_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_new_ref_ext_len, tvb, offset, 2, ENC_BIG_ENDIAN, &len);

      offset += 2;

      offset = dissect_etf_type("Node", pinfo, tvb, offset, tree);

      proto_tree_add_item(tree, hf_erldp_new_ref_ext_creation, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      for (i=0; i<len; i++) {

        id = tvb_get_ntohl(tvb, offset);

        proto_tree_add_uint_format(tree, hf_erldp_new_ref_ext_id, tvb, offset, 4,

                            id, "ID[%d]: 0x%08X", i, id);

        offset += 4;

      }

      break;

    case FUN_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_fun_ext_num_free, tvb, offset, 4, ENC_BIG_ENDIAN, &len);

      offset += 4;

      offset = dissect_etf_type("Pid", pinfo, tvb, offset, tree);

      offset = dissect_etf_type("Module", pinfo, tvb, offset, tree);

      offset = dissect_etf_type("Index", pinfo, tvb, offset, tree);

      offset = dissect_etf_type("Unique", pinfo, tvb, offset, tree);

      for (i = 0; i < len; i++) {

          char buf[ITEM_LABEL_LENGTH];

          snprintf(buf, sizeof(buf), "Free Var[%u]", i + 1);

          offset = dissect_etf_type(buf, pinfo, tvb, offset, tree);

      }

      break;

    case NEW_FUN_EXT:

      proto_tree_add_item(tree, hf_erldp_new_fun_ext_size, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      proto_tree_add_item(tree, hf_erldp_new_fun_ext_arity, tvb, offset, 1, ENC_BIG_ENDIAN);

      offset += 1;

      proto_tree_add_item(tree, hf_erldp_new_fun_ext_uniq, tvb, offset, 16, ENC_NA);

      offset += 16;

      proto_tree_add_item(tree, hf_erldp_new_fun_ext_index, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      proto_tree_add_item_ret_uint(tree, hf_erldp_new_fun_ext_num_free, tvb, offset, 4, ENC_BIG_ENDIAN, &len);

      offset += 4;

      offset = dissect_etf_type("Module", pinfo, tvb, offset, tree);

      offset = dissect_etf_type("OldIndex", pinfo, tvb, offset, tree);

      offset = dissect_etf_type("OldUnique", pinfo, tvb, offset, tree);

      offset = dissect_etf_type("Pid", pinfo, tvb, offset, tree);

      for (i = 0; i < len; i++) {

          char buf[ITEM_LABEL_LENGTH];

          snprintf(buf, sizeof(buf), "Free Var[%u]", i + 1);

          offset = dissect_etf_type(buf, pinfo, tvb, offset, tree);

      }

      break;

    case EXPORT_EXT:

      offset = dissect_etf_type("Module", pinfo, tvb, offset, tree);

      offset = dissect_etf_type("Function", pinfo, tvb, offset, tree);

      offset = dissect_etf_type("Arity", pinfo, tvb, offset, tree);

      break;

    case RECORD_EXT:

      proto_tree_add_item_ret_uint(tree, hf_erldp_record_ext_num_fields, tvb, offset, 4, ENC_BIG_ENDIAN, &len);

      offset += 4;

      proto_tree_add_bitmask(tree, tvb, offset, hf_erldp_record_ext_flags,

                             ett_etf_record_flags, record_flags, ENC_NA);

      offset += 1;

      offset = dissect_etf_type("Module", pinfo, tvb, offset, tree);

      offset = dissect_etf_type("Name", pinfo, tvb, offset, tree);

      for (i = 0; i < len; i++) {

          char buf[ITEM_LABEL_LENGTH];

          snprintf(buf, sizeof(buf), "Field Name[%u]", i + 1);

          offset = dissect_etf_type(buf, pinfo, tvb, offset, tree);

      }

      for (i = 0; i < len; i++) {

          char buf[ITEM_LABEL_LENGTH];

          snprintf(buf, sizeof(buf), "Value[%u]", i + 1);

          offset = dissect_etf_type(buf, pinfo, tvb, offset, tree);

      }

      break;

    case LOCAL_EXT:

      /* A hash, then an encoding known only to the node that made it */

      proto_tree_add_item(tree, hf_erldp_local_ext_hash, tvb, offset, 4, ENC_BIG_ENDIAN);

      offset += 4;

      len = tvb_reported_length_remaining(tvb, offset);

      if (len > 0)

        proto_tree_add_item(tree, hf_erldp_local_ext_data, tvb, offset, len, ENC_NA);

      offset += len;

      break;

    default:

      /* Its length is unknown, so nothing after it can be decoded */

      proto_tree_add_expert(tree, pinfo, &ei_erldp_unknown_tag, tvb, offset - 1, 1);

      len = tvb_reported_length_remaining(tvb, offset);

      if (len > 0)

        proto_tree_add_item(tree, hf_erldp_undecoded, tvb, offset, len, ENC_NA);

      offset += len;

      break;

  }

  decrement_dissection_depth(pinfo);

  return offset;

}

static int dissect_etf_pdu_data(packet_info *pinfo, tvbuff_t *tvb, int offset, proto_tree *tree) {

  uint8_t ctl_op = 0;

  int ctl_offset = offset;

  proto_tree *ctl_tree = NULL;

  static int * const altact_flags[] = {

    &hf_erldp_altact_flags_prio,

    &hf_erldp_altact_flags_token,

    &hf_erldp_altact_flags_alias,

    &hf_erldp_altact_flags_name,

    &hf_erldp_altact_flags_exit,

    NULL

  };

  if ((tvb_get_uint8(tvb, offset) == SMALL_TUPLE_EXT) && (tvb_get_uint8(tvb, offset + 2) == SMALL_INTEGER_EXT)) {

    ctl_op = tvb_get_uint8(tvb, offset + 3);

    col_add_str(pinfo->cinfo, COL_INFO, val_to_str(pinfo->pool, ctl_op, VALS(erldp_ctlmsg_vals), "unknown ControlMessage operation (%d)"));

  }

  offset = dissect_etf_type_ret_tree("ControlMessage", pinfo, tvb, offset, tree, &ctl_tree);

  /* {37, Flags, SenderPid, To} or {37, Flags, SenderPid, To, Token} */

  if ((ctl_op == DOP_ALTACT_SIG_SEND) && (tvb_get_uint8(tvb, ctl_offset + 1) >= 4) &&

      (tvb_get_uint8(tvb, ctl_offset + 4) == SMALL_INTEGER_EXT)) {

    proto_tree_add_bitmask(ctl_tree, tvb, ctl_offset + 5, hf_erldp_altact_flags,

                           ett_etf_altact_flags, altact_flags, ENC_NA);

  }

  if (tvb_reported_length_remaining(tvb, offset) > 0)

    offset = dissect_etf_type("Message", pinfo, tvb, offset, tree);

  return offset;

}

static int dissect_etf_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, const char *label) {

  int offset = 0;

  uint8_t mag;

  uint32_t tag;

  proto_item *ti;

  proto_tree *etf_tree;

  mag = tvb_get_uint8(tvb, offset);

  if (mag != VERSION_MAGIC) {

    return 0;

  }

  etf_tree = proto_tree_add_subtree(tree, tvb, offset, -1, ett_etf, &ti, (label) ? label : "External Term Format");

  proto_tree_add_item(etf_tree, hf_etf_version_magic, tvb, offset, 1, ENC_BIG_ENDIAN);

  offset++;

  proto_tree_add_item_ret_uint(etf_tree, hf_etf_dist_header_tag, tvb, offset, 1, ENC_BIG_ENDIAN, &tag);

  offset++;

  if (!label)

    proto_item_set_text(ti, "%s", val_to_str(pinfo->pool, tag, VALS(etf_header_tag_vals), "unknown tag (%d)"));

  switch (tag) {

    case DIST_HEADER:

      offset = dissect_etf_dist_header(pinfo, tvb, offset, etf_tree);

      proto_item_set_len(ti, offset);

      dissect_etf_pdu_data(pinfo, tvb, offset, tree);

      break;

    case DIST_FRAG_HEADER:

    case DIST_FRAG_CONT:

    {

      uint64_t sequence_id, fragment_id;

      bool save_fragmented;

      fragment_head *frag_msg = NULL;

      tvbuff_t *next_tvb = NULL;

      int len_rem;

      proto_tree_add_item_ret_uint64(etf_tree, hf_erldp_sequence_id, tvb, offset, 8, ENC_BIG_ENDIAN, &sequence_id);

      offset += 8;

      proto_tree_add_item_ret_uint64(etf_tree, hf_erldp_fragment_id, tvb, offset, 8, ENC_BIG_ENDIAN, &fragment_id);

      offset += 8;

      save_fragmented = pinfo->fragmented;

      len_rem = tvb_reported_length_remaining(tvb, offset);

      if (len_rem <= 0)

        return offset;

      pinfo->fragmented = true;

      frag_msg = fragment_add_seq_next(&erldp_reassembly_table,

                                       tvb, offset, pinfo, (uint32_t)sequence_id, NULL,

                                       len_rem, fragment_id != 1);

      next_tvb = process_reassembled_data(tvb, offset, pinfo,

                                          "Reassembled ErlDP", frag_msg,

                                          &etf_frag_items, NULL, tree);

      if (next_tvb == NULL)

      { /* make a new subset */

        next_tvb = tvb_new_subset_remaining(tvb, offset);

        call_data_dissector(next_tvb, pinfo, tree);

        col_append_fstr(pinfo->cinfo, COL_INFO, " (Fragment ID: %" PRIu64 ")", fragment_id);

      }

      else

      {

        offset = dissect_etf_dist_header(pinfo, next_tvb, 0, etf_tree);

        proto_item_set_len(ti, offset);

        dissect_etf_pdu_data(pinfo, next_tvb, offset, tree);

        col_append_fstr(pinfo->cinfo, COL_INFO, " (Reassembled, Fragment ID: %" PRIu64 ")", fragment_id);

      }