/* packet-sdlc.c * Routines for SDLC frame disassembly * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 * * 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 #include #include /* * See: * * http://web.archive.org/web/20020206033700/http://www.wanresources.com/snacell.html * * http://web.archive.org/web/20150522015710/http://www.protocols.com/pbook/sna.htm * * Systems Network Architecture Formats, GA27-3136-20: * https://publibz.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/D50A5007/CCONTENTS */ void proto_register_sdlc(void); void proto_reg_handoff_sdlc(void); static int proto_sdlc = -1; static int hf_sdlc_address = -1; static int hf_sdlc_control = -1; static int hf_sdlc_n_r = -1; static int hf_sdlc_n_s = -1; static int hf_sdlc_p = -1; static int hf_sdlc_f = -1; static int hf_sdlc_s_ftype = -1; static int hf_sdlc_u_modifier_cmd = -1; static int hf_sdlc_u_modifier_resp = -1; static int hf_sdlc_ftype_i = -1; static int hf_sdlc_ftype_s_u = -1; static gint ett_sdlc = -1; static gint ett_sdlc_control = -1; static dissector_handle_t sna_handle; static const xdlc_cf_items sdlc_cf_items = { &hf_sdlc_n_r, &hf_sdlc_n_s, &hf_sdlc_p, &hf_sdlc_f, &hf_sdlc_s_ftype, &hf_sdlc_u_modifier_cmd, &hf_sdlc_u_modifier_resp, &hf_sdlc_ftype_i, &hf_sdlc_ftype_s_u }; static int dissect_sdlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { proto_tree *sdlc_tree; proto_item *sdlc_ti; guint8 addr; guint16 control; int sdlc_header_len; gboolean is_response; tvbuff_t *next_tvb; col_set_str(pinfo->cinfo, COL_PROTOCOL, "SDLC"); col_clear(pinfo->cinfo, COL_INFO); addr = tvb_get_guint8(tvb, 0); sdlc_header_len = 1; /* address */ /* * XXX - is there something in the SDLC header that indicates * how to interpret "command vs. response" based on the * direction? */ if (pinfo->p2p_dir == P2P_DIR_SENT) { is_response = FALSE; col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE"); col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE"); } else { /* XXX - what if the direction is unknown? */ is_response = TRUE; col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE"); col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE"); } sdlc_ti = proto_tree_add_item(tree, proto_sdlc, tvb, 0, -1, ENC_NA); sdlc_tree = proto_item_add_subtree(sdlc_ti, ett_sdlc); proto_tree_add_uint(sdlc_tree, hf_sdlc_address, tvb, 0, 1, addr); /* * XXX - SDLC has a mod-128 mode as well as a mod-7 mode. * We can infer the mode from an SNRM/SRME frame, but if * we don't see one of them, we may have to have a preference * to control what to use. */ control = dissect_xdlc_control(tvb, 1, pinfo, sdlc_tree, hf_sdlc_control, ett_sdlc_control, &sdlc_cf_items, NULL, NULL, NULL, is_response, FALSE, FALSE); sdlc_header_len += XDLC_CONTROL_LEN(control, FALSE); proto_item_set_len(sdlc_ti, sdlc_header_len); /* * XXX - is there an FCS at the end, at least in Sniffer * captures? (There doesn't appear to be.) */ next_tvb = tvb_new_subset_remaining(tvb, sdlc_header_len); if (XDLC_IS_INFORMATION(control)) { /* call the SNA dissector */ call_dissector(sna_handle, next_tvb, pinfo, tree); } else call_data_dissector(next_tvb, pinfo, tree); return tvb_captured_length(tvb); } void proto_register_sdlc(void) { static hf_register_info hf[] = { { &hf_sdlc_address, { "Address Field", "sdlc.address", FT_UINT8, BASE_HEX, NULL, 0x0, "Address", HFILL }}, { &hf_sdlc_control, { "Control Field", "sdlc.control", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL }}, { &hf_sdlc_n_r, { "N(R)", "sdlc.control.n_r", FT_UINT8, BASE_DEC, NULL, XDLC_N_R_MASK, NULL, HFILL }}, { &hf_sdlc_n_s, { "N(S)", "sdlc.control.n_s", FT_UINT8, BASE_DEC, NULL, XDLC_N_S_MASK, NULL, HFILL }}, { &hf_sdlc_p, { "Poll", "sdlc.control.p", FT_BOOLEAN, 8, TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }}, { &hf_sdlc_f, { "Final", "sdlc.control.f", FT_BOOLEAN, 8, TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }}, { &hf_sdlc_s_ftype, { "Supervisory frame type", "sdlc.control.s_ftype", FT_UINT8, BASE_HEX, VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL }}, { &hf_sdlc_u_modifier_cmd, { "Command", "sdlc.control.u_modifier_cmd", FT_UINT8, BASE_HEX, VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL }}, { &hf_sdlc_u_modifier_resp, { "Response", "sdlc.control.u_modifier_resp", FT_UINT8, BASE_HEX, VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL }}, { &hf_sdlc_ftype_i, { "Frame type", "sdlc.control.ftype", FT_UINT8, BASE_HEX, VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL }}, { &hf_sdlc_ftype_s_u, { "Frame type", "sdlc.control.ftype", FT_UINT8, BASE_HEX, VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }}, }; static gint *ett[] = { &ett_sdlc, &ett_sdlc_control, }; proto_sdlc = proto_register_protocol( "Synchronous Data Link Control (SDLC)", "SDLC", "sdlc"); proto_register_field_array(proto_sdlc, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); } void proto_reg_handoff_sdlc(void) { dissector_handle_t sdlc_handle; /* * Get handle for the SNA dissector. */ sna_handle = find_dissector_add_dependency("sna", proto_sdlc); sdlc_handle = create_dissector_handle(dissect_sdlc, proto_sdlc); dissector_add_uint("wtap_encap", WTAP_ENCAP_SDLC, sdlc_handle); } /* * Editor modelines - http://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 8 * tab-width: 8 * indent-tabs-mode: t * End: * * vi: set shiftwidth=8 tabstop=8 noexpandtab: * :indentSize=8:tabSize=8:noTabs=false: */