/* packet-x75.c * Routines for X.75 frame disassembly * Manawyrm * * based on lapb dissector by * Olivier Abad * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include #include #include void proto_register_x75(void); void proto_reg_handoff_x75(void); #define X75_ADDRESS_SLP_STE_A 0x03 #define X75_ADDRESS_SLP_STE_B 0x01 #define X75_ADDRESS_MLP_STE_C 0x0F #define X75_ADDRESS_MLP_STE_D 0x07 static int proto_x75 = -1; static int hf_x75_address = -1; static int hf_x75_control = -1; static int hf_x75_n_r = -1; static int hf_x75_n_s = -1; static int hf_x75_p = -1; static int hf_x75_f = -1; static int hf_x75_s_ftype = -1; static int hf_x75_u_modifier_cmd = -1; static int hf_x75_u_modifier_resp = -1; static int hf_x75_ftype_i = -1; static int hf_x75_ftype_s_u = -1; static gint ett_x75 = -1; static gint ett_x75_control = -1; static dissector_handle_t data_handle; static dissector_handle_t x75_handle; static const xdlc_cf_items x75_cf_items = { &hf_x75_n_r, &hf_x75_n_s, &hf_x75_p, &hf_x75_f, &hf_x75_s_ftype, &hf_x75_u_modifier_cmd, &hf_x75_u_modifier_resp, &hf_x75_ftype_i, &hf_x75_ftype_s_u }; static int dissect_x75(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { proto_tree *x75_tree, *ti; guint16 control; int is_response; guint8 byte0; tvbuff_t *next_tvb; col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.75"); col_set_str(pinfo->cinfo, COL_RES_NET_DST, "Broadcast"); byte0 = tvb_get_guint8(tvb, 0); if (byte0 != X75_ADDRESS_SLP_STE_A && byte0 != X75_ADDRESS_SLP_STE_B && byte0 != X75_ADDRESS_MLP_STE_C && byte0 != X75_ADDRESS_MLP_STE_D) /* invalid X.75 frame */ { col_set_str(pinfo->cinfo, COL_INFO, "Invalid X.75 frame"); if (tree) proto_tree_add_protocol_format(tree, proto_x75, tvb, 0, -1, "Invalid X.75 frame"); return 1; } // Clear lower layer src/dst address types, so our custom names // are shown in the Packet List pane pinfo->src.type = AT_NONE; pinfo->dst.type = AT_NONE; switch (pinfo->p2p_dir) { case P2P_DIR_SENT: if (byte0 == X75_ADDRESS_SLP_STE_A || byte0 == X75_ADDRESS_SLP_STE_B) { col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE A"); col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE B"); } else { col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE C"); col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE D"); } if (byte0 == X75_ADDRESS_SLP_STE_A || byte0 == X75_ADDRESS_MLP_STE_C) is_response = TRUE; else is_response = FALSE; break; case P2P_DIR_RECV: if (byte0 == X75_ADDRESS_SLP_STE_A || byte0 == X75_ADDRESS_SLP_STE_B) { col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE B"); col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE A"); } else { col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE D"); col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE C"); } if (byte0 == X75_ADDRESS_SLP_STE_B || byte0 == X75_ADDRESS_MLP_STE_D) is_response = TRUE; else is_response = FALSE; break; default: is_response = FALSE; break; } if (is_response) { col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.75 RSP"); } else { col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.75 CMD"); } ti = proto_tree_add_protocol_format(tree, proto_x75, tvb, 0, 2, "X.75"); x75_tree = proto_item_add_subtree(ti, ett_x75); proto_tree_add_uint(x75_tree, hf_x75_address, tvb, 0, 1, byte0); control = dissect_xdlc_control(tvb, 1, pinfo, x75_tree, hf_x75_control, ett_x75_control, &x75_cf_items, NULL, NULL, NULL, is_response, FALSE, FALSE); /* information frame ==> data */ if (XDLC_IS_INFORMATION(control)) { next_tvb = tvb_new_subset_remaining(tvb, 2); int len = tvb_reported_length_remaining(next_tvb, 0); // limit number of bytes being shown in COL_INFO if (len > 128) len = 128; char *tmp = (char*)wmem_alloc(pinfo->pool, len + 1); tmp[len] = 0x00; tvb_memcpy(next_tvb, tmp, 0, len); col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", tmp); wmem_free(pinfo->pool, tmp); call_dissector(data_handle, next_tvb, pinfo, tree); } return tvb_captured_length(tvb); } void proto_register_x75(void) { static hf_register_info hf[] = { { &hf_x75_address, { "Address", "x75.address", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }}, { &hf_x75_control, { "Control Field", "x75.control", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }}, { &hf_x75_n_r, { "N(R)", "x75.control.n_r", FT_UINT8, BASE_DEC, NULL, XDLC_N_R_MASK, NULL, HFILL }}, { &hf_x75_n_s, { "N(S)", "x75.control.n_s", FT_UINT8, BASE_DEC, NULL, XDLC_N_S_MASK, NULL, HFILL }}, { &hf_x75_p, { "Poll", "x75.control.p", FT_BOOLEAN, 8, TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }}, { &hf_x75_f, { "Final", "x75.control.f", FT_BOOLEAN, 8, TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }}, { &hf_x75_s_ftype, { "Supervisory frame type", "x75.control.s_ftype", FT_UINT8, BASE_HEX, VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL }}, { &hf_x75_u_modifier_cmd, { "Command", "x75.control.u_modifier_cmd", FT_UINT8, BASE_HEX, VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL }}, { &hf_x75_u_modifier_resp, { "Response", "x75.control.u_modifier_resp", FT_UINT8, BASE_HEX, VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL }}, { &hf_x75_ftype_i, { "Frame type", "x75.control.ftype", FT_UINT8, BASE_HEX, VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL }}, { &hf_x75_ftype_s_u, { "Frame type", "x75.control.ftype", FT_UINT8, BASE_HEX, VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }}, }; static gint *ett[] = { &ett_x75, &ett_x75_control, }; proto_x75 = proto_register_protocol("Async data over ISDN (X.75)", "X.75", "x75"); proto_register_field_array (proto_x75, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); x75_handle = register_dissector("x75", dissect_x75, proto_x75); } void proto_reg_handoff_x75(void) { data_handle = find_dissector("data"); dissector_add_uint("wtap_encap", WTAP_ENCAP_LAPB, x75_handle); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 4 * tab-width: 8 * indent-tabs-mode: nil * End: * * vi: set shiftwidth=4 tabstop=8 expandtab: * :indentSize=4:tabSize=8:noTabs=true: */