epan/dissectors/packet-v5ef.c

   1 /* packet-v5ef.c
   2  * Routines for V5 envelope function frame disassembly
   3  * Rolf Fiedler <rolf.fiedler@innoventif.de>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11 /*
  12  * V5 bitstream over HDLC handling
  13  *
  14  * V5 references:
  15  *
  16  * ETS 300 324-1
  17  * ETS 300 347-1
  18  */
  19
  20 #include "config.h"
  21
  22 #include <epan/packet.h>
  23 #include <wiretap/wtap.h>
  24
  25 void proto_register_v5ef(void);
  26 void proto_reg_handoff_v5ef(void);
  27
  28 static int proto_v5ef;
  29 static int hf_v5ef_direction;
  30 static int hf_v5ef_address;
  31 static int hf_v5ef_eah;
  32 static int hf_v5ef_ea1;
  33 static int hf_v5ef_eal;
  34 static int hf_v5ef_ea2;
  35
  36 static int ett_v5ef;
  37 static int ett_v5ef_address;
  38
  39 static dissector_handle_t v5dl_handle, lapd_phdr_handle, v5ef_handle;
  40
  41
  42 /*
  43  * Bits in the address field.
  44  */
  45 #define V5EF_EAH                0xfc00  /* Service Access Point Identifier */
  46 #define V5EF_EAH_SHIFT          10
  47 #define V5EF_EA1                0x0100  /* First Address Extension bit */
  48 #define V5EF_EAL                0x00fe  /* Terminal Endpoint Identifier */
  49 #define V5EF_EAL_SHIFT          1
  50 #define V5EF_EA2                0x0001  /* Second Address Extension bit */
  51
  52 static const value_string v5ef_direction_vals[] = {
  53         { 0,            "AN->LE"},
  54         { 1,            "LE->AN"},
  55         { 0,            NULL }
  56 };
  57
  58 #define MAX_V5EF_PACKET_LEN 1024
  59
  60 static int
  61 dissect_v5ef(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
  62 {
  63         struct isdn_phdr *isdn = (struct isdn_phdr *)data;
  64         proto_tree      *v5ef_tree, *addr_tree;
  65         proto_item      *v5ef_ti, *addr_ti;
  66         int              direction;
  67         int              v5ef_header_len;
  68         uint16_t                 addr, eah, eal, efaddr;
  69         tvbuff_t        *next_tvb;
  70         const char      *srcname = "src";
  71         const char      *dstname = "dst";
  72
  73         col_set_str(pinfo->cinfo, COL_PROTOCOL, "V5-EF");
  74         col_clear(pinfo->cinfo, COL_INFO);
  75
  76         addr            = tvb_get_ntohs(tvb, 0);
  77         eah             = (addr & V5EF_EAH) >> V5EF_EAH_SHIFT;
  78         eal             = (addr & V5EF_EAL) >> V5EF_EAL_SHIFT;
  79         efaddr          = (eah << 7) + eal;
  80         v5ef_header_len = 2;    /* addr */
  81
  82         direction = isdn->uton;
  83         if (direction==0) {
  84                 srcname = "LE";
  85                 dstname = "AN";
  86          } else if (direction > 0) {
  87                 srcname = "AN";
  88                 dstname = "LE";
  89         }
  90         col_set_str(pinfo->cinfo, COL_RES_DL_SRC, srcname);
  91         col_set_str(pinfo->cinfo, COL_RES_DL_DST, dstname);
  92
  93         if (tree) {
  94                 proto_item *direction_ti;
  95
  96                 v5ef_ti = proto_tree_add_item(tree, proto_v5ef, tvb, 0, -1,
  97                     ENC_NA);
  98                 v5ef_tree = proto_item_add_subtree(v5ef_ti, ett_v5ef);
  99
 100                 /*
 101                  * Don't show the direction if we don't know it.
 102                  */
 103                 if (direction != P2P_DIR_UNKNOWN) {
 104                         direction_ti = proto_tree_add_uint(v5ef_tree, hf_v5ef_direction,
 105                                                            tvb, 0, 0, direction);
 106                         proto_item_set_generated(direction_ti);
 107                 }
 108
 109                 addr_ti = proto_tree_add_uint(v5ef_tree, hf_v5ef_address, tvb,
 110                     0, 2, addr);
 111                 addr_tree = proto_item_add_subtree(addr_ti, ett_v5ef_address);
 112
 113                 proto_tree_add_uint(addr_tree, hf_v5ef_eah,  tvb, 0, 1, addr);
 114                 proto_tree_add_uint(addr_tree, hf_v5ef_ea1, tvb, 0, 1, addr);
 115                 proto_tree_add_uint(addr_tree, hf_v5ef_eal, tvb, 1, 1, addr);
 116                 proto_tree_add_uint(addr_tree, hf_v5ef_ea2, tvb, 1, 1, addr);
 117         }
 118         else {
 119                 v5ef_ti   = NULL;
 120                 v5ef_tree = NULL;
 121         }
 122
 123         if (tree)
 124                 proto_item_set_len(v5ef_ti, v5ef_header_len);
 125
 126         next_tvb = tvb_new_subset_remaining(tvb, v5ef_header_len);
 127
 128         if (efaddr>8175)
 129                 call_dissector(v5dl_handle,next_tvb, pinfo, tree);
 130         else
 131                 call_dissector_with_data(lapd_phdr_handle, next_tvb, pinfo, tree, isdn);
 132
 133         return tvb_captured_length(tvb);
 134 }
 135
 136 void
 137 proto_register_v5ef(void)
 138 {
 139         static hf_register_info hf[] = {
 140
 141         { &hf_v5ef_direction,
 142           { "Direction", "v5ef.direction", FT_UINT8, BASE_DEC, VALS(v5ef_direction_vals), 0x0,
 143                 NULL, HFILL }},
 144
 145         { &hf_v5ef_address,
 146           { "Address Field", "v5ef.address", FT_UINT16, BASE_HEX, NULL, 0x0,
 147                 NULL, HFILL }},
 148
 149         { &hf_v5ef_eah,
 150           { "EAH", "v5ef.eah", FT_UINT16, BASE_DEC, NULL, V5EF_EAH,
 151                 "Envelope Address High Part", HFILL }},
 152
 153         { &hf_v5ef_ea1,
 154           { "EA1", "v5ef.ea1", FT_UINT16, BASE_DEC, NULL, V5EF_EA1,
 155                 "First Address Extension bit", HFILL }},
 156
 157         { &hf_v5ef_eal,
 158           { "EAL", "v5ef.eal", FT_UINT16, BASE_DEC, NULL, V5EF_EAL,
 159                 "Envelope Address Low Part", HFILL }},
 160
 161         { &hf_v5ef_ea2,
 162           { "EA2", "v5ef.ea2", FT_UINT16, BASE_DEC, NULL, V5EF_EA2,
 163                 "Second Address Extension bit", HFILL }},
 164         };
 165
 166         static int *ett[] = {
 167                 &ett_v5ef,
 168                 &ett_v5ef_address,
 169         };
 170
 171         proto_v5ef = proto_register_protocol("V5 Envelope Function (v5ef)",
 172                                          "v5ef", "v5ef");
 173         proto_register_field_array (proto_v5ef, hf, array_length(hf));
 174         proto_register_subtree_array(ett, array_length(ett));
 175
 176         v5ef_handle = register_dissector("v5ef", dissect_v5ef, proto_v5ef);
 177 }
 178
 179 void
 180 proto_reg_handoff_v5ef(void)
 181 {
 182         dissector_add_uint("wtap_encap", WTAP_ENCAP_V5_EF, v5ef_handle);
 183
 184         lapd_phdr_handle = find_dissector_add_dependency("lapd-phdr", proto_v5ef);
 185         v5dl_handle = find_dissector_add_dependency("v5dl", proto_v5ef);
 186 }
 187
 188 /*
 189  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 190  *
 191  * Local variables:
 192  * c-basic-offset: 8
 193  * tab-width: 8
 194  * indent-tabs-mode: t
 195  * End:
 196  *
 197  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 198  * :indentSize=8:tabSize=8:noTabs=false:
 199  */