/* packet-cl3dcw.c * Routines for CableLabs Dual-Channel Wi-Fi Messaging Protocol Dissection * Copyright 2019 Jon Dennis * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later * * CableLabs Specifications Can Be Found At: * https://www.cablelabs.com/specs */ #include "config.h" #include #include void proto_register_cl3dcw(void); void proto_reg_handoff_cl3dcw(void); static dissector_handle_t cl3dcw_handle; #define SSID_MAX_LENGTH 32 /* persistent handles for this dissector */ static int proto_cl3dcw; static gint ett_cl3dcw; static int hf_cl3dcw_type; static int hf_cl3dcw_dccount; static int hf_cl3dcw_datamacaddrcount; static int hf_cl3dcw_datassidcount; static int hf_cl3dcw_dcmacaddr; static int hf_cl3dcw_dcssid; static int hf_cl3dcw_dcbond; static gint ett_cl3dcw_dcbond; static expert_field ei_cl3dcw_unknown_type; static expert_field ei_cl3dcw_nodc; static expert_field ei_cl3dcw_ssid_too_big; /* message id types */ #define DCWMSG_STA_JOIN 0x01 #define DCWMSG_STA_UNJOIN 0x02 #define DCWMSG_STA_ACK 0x11 #define DCWMSG_STA_NACK 0x12 #define DCWMSG_AP_ACCEPT_STA 0x21 #define DCWMSG_AP_REJECT_STA 0x22 #define DCWMSG_AP_ACK_DISCONNECT 0x41 #define DCWMSG_AP_QUIT 0x99 /* message type strings */ static const value_string cl3dcw_msg_types[] = { {DCWMSG_STA_JOIN, "Station Join" }, {DCWMSG_STA_UNJOIN, "Station Unjoin" }, {DCWMSG_STA_ACK, "Station Ack" }, {DCWMSG_STA_NACK, "Station Nack" }, {DCWMSG_AP_ACCEPT_STA, "AP Accept Station" }, {DCWMSG_AP_REJECT_STA, "AP Reject Station" }, {DCWMSG_AP_ACK_DISCONNECT, "AP Ack Disconnect" }, {DCWMSG_AP_QUIT, "AQ Quit" }, {0, NULL} }; static gint dissect_sta_join(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) { guint32 data_macaddr_count; gint offset; proto_tree_add_item_ret_uint(tree, hf_cl3dcw_datamacaddrcount, tvb, 0, 1, ENC_NA, &data_macaddr_count); if (data_macaddr_count < 1) { expert_add_info(pinfo, ti, &ei_cl3dcw_nodc); } offset = 1; while(data_macaddr_count--) { proto_tree_add_item(tree, hf_cl3dcw_dcmacaddr, tvb, offset, 6, ENC_NA); offset += 6; } return offset; } static gint dissect_sta_unjoin(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) { guint32 data_macaddr_count; gint offset; proto_tree_add_item_ret_uint(tree, hf_cl3dcw_datamacaddrcount, tvb, 0, 1, ENC_NA, &data_macaddr_count); if (data_macaddr_count < 1) { expert_add_info(pinfo, ti, &ei_cl3dcw_nodc); } offset = 1; while (data_macaddr_count--) { proto_tree_add_item(tree, hf_cl3dcw_dcmacaddr, tvb, offset, 6, ENC_NA); offset += 6; } return offset; } static gint dissect_sta_ack(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) { proto_item *bond_item; proto_tree *bond_tree; guint32 data_channel_count; guint8 ssid_len; guint8 *ssidbuf; gint offset; proto_tree_add_item_ret_uint(tree, hf_cl3dcw_dccount, tvb, 0, 1, ENC_NA, &data_channel_count); if (data_channel_count < 1) { expert_add_info(pinfo, ti, &ei_cl3dcw_nodc); } offset = 1; while (data_channel_count--) { /* parse each data channel bond... * format is 6-byte mac addr + 1 byte ssid string length + ssid string */ ssid_len = tvb_get_guint8(tvb, offset + 6); /* +6 = skip over mac address */ if (ssid_len > SSID_MAX_LENGTH) { expert_add_info(pinfo, ti, &ei_cl3dcw_ssid_too_big); } ssidbuf = tvb_get_string_enc(pinfo->pool, tvb, offset + 6 + 1, ssid_len, ENC_ASCII); /* +6+1 = skip over mac address and length field */ /* add the data channel bond sub-tree item */ bond_item = proto_tree_add_item(tree, hf_cl3dcw_dcbond, tvb, offset, 6, ENC_NA); proto_item_append_text(bond_item, " -> \"%s\"", ssidbuf); proto_item_set_len(bond_item, 6 + 1 + ssid_len); bond_tree = proto_item_add_subtree(bond_item, ett_cl3dcw_dcbond); /* add the MAC address... */ proto_tree_add_item(bond_tree, hf_cl3dcw_dcmacaddr, tvb, offset, 6, ENC_NA); offset += 6; /* add the SSID string * XXX the intent here is to highlight the leading length byte in the hex dump * without printing it in the string... i suspect there is a better way of doing this */ proto_tree_add_string_format(bond_tree, hf_cl3dcw_dcssid, tvb, offset, 1 + ssid_len, "", "Data Channel SSID: %s", ssidbuf); offset += 1 + ssid_len; } return offset; } static gint dissect_sta_nack(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) { guint32 data_macaddr_count; gint offset; proto_tree_add_item_ret_uint(tree, hf_cl3dcw_datamacaddrcount, tvb, 0, 1, ENC_NA, &data_macaddr_count); if (data_macaddr_count < 1) { expert_add_info(pinfo, ti, &ei_cl3dcw_nodc); } offset = 1; while (data_macaddr_count--) { proto_tree_add_item(tree, hf_cl3dcw_dcmacaddr, tvb, offset, 6, ENC_NA); offset += 6; } return offset; } static gint dissect_ap_accept_sta(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) { guint32 data_ssid_count; guint8 ssid_len; guint8 *ssidbuf; gint offset; proto_tree_add_item_ret_uint(tree, hf_cl3dcw_datassidcount, tvb, 0, 1, ENC_NA, &data_ssid_count); if (data_ssid_count < 1) { expert_add_info(pinfo, ti, &ei_cl3dcw_nodc); } offset = 1; while (data_ssid_count--) { ssid_len = tvb_get_guint8(tvb, offset); if (ssid_len > SSID_MAX_LENGTH) { expert_add_info(pinfo, ti, &ei_cl3dcw_ssid_too_big); } ssidbuf = tvb_get_string_enc(pinfo->pool, tvb, offset + 1, ssid_len, ENC_ASCII); /* +1 = skip over length field */ /* add the SSID string * XXX the intent here is to highlight the leading length byte in the hex dump * without printing it in the string... i suspect there is a better way of doing this */ proto_tree_add_string_format(tree, hf_cl3dcw_dcssid, tvb, offset, 1 + ssid_len, "", "Data Channel SSID: %s", ssidbuf); offset += 1 + ssid_len; } return offset; } static gint dissect_ap_reject_sta(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) { guint32 data_macaddr_count; gint offset; proto_tree_add_item_ret_uint(tree, hf_cl3dcw_datamacaddrcount, tvb, 0, 1, ENC_NA, &data_macaddr_count); if (data_macaddr_count < 1) { expert_add_info(pinfo, ti, &ei_cl3dcw_nodc); } offset = 1; while (data_macaddr_count--) { proto_tree_add_item(tree, hf_cl3dcw_dcmacaddr, tvb, offset, 6, ENC_NA); offset += 6; } return offset; } /* called for each incomming framing matching our CL3 (sub-)protocol id: */ static int dissect_cl3dcw(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree _U_, void *data _U_) { proto_item *ti; proto_tree *cl3dcw_tree; tvbuff_t *tvb_msg; gint total_dcw_message_len; guint8 type; /* parse the header fields */ total_dcw_message_len = 1; type = tvb_get_guint8(tvb, 0); /* setup the "packet summary view" fields */ col_set_str(pinfo->cinfo, COL_PROTOCOL, "CL3-DCW"); col_clear(pinfo->cinfo, COL_INFO); col_add_fstr(pinfo->cinfo, COL_INFO, "Dual-Channel Wi-Fi %s [Type 0x%02X]", val_to_str_const(type, cl3dcw_msg_types, "Unknown"), (guint)type); /* create a tree node for us... */ ti = proto_tree_add_protocol_format(tree, proto_cl3dcw, tvb, 0, tvb_captured_length(tvb), "Dual-Channel Wi-Fi Control Message"); cl3dcw_tree = proto_item_add_subtree(ti, ett_cl3dcw); tvb_msg = tvb_new_subset_remaining(tvb, 1); /* display dcw fields: */ proto_tree_add_uint(cl3dcw_tree, hf_cl3dcw_type, tvb, 0, 1, type); /* parse the message by type... */ switch (type) { case DCWMSG_STA_JOIN: total_dcw_message_len += dissect_sta_join(tvb_msg, pinfo, cl3dcw_tree, ti); break; case DCWMSG_STA_UNJOIN: total_dcw_message_len += dissect_sta_unjoin(tvb_msg, pinfo, cl3dcw_tree, ti); break; case DCWMSG_STA_ACK: total_dcw_message_len += dissect_sta_ack(tvb_msg, pinfo, cl3dcw_tree, ti); break; case DCWMSG_STA_NACK: total_dcw_message_len += dissect_sta_nack(tvb_msg, pinfo, cl3dcw_tree, ti); break; case DCWMSG_AP_ACCEPT_STA: total_dcw_message_len += dissect_ap_accept_sta(tvb_msg, pinfo, cl3dcw_tree, ti); break; case DCWMSG_AP_REJECT_STA: total_dcw_message_len += dissect_ap_reject_sta(tvb_msg, pinfo, cl3dcw_tree, ti); break; case DCWMSG_AP_ACK_DISCONNECT: /* nothing to really dissect */ break; case DCWMSG_AP_QUIT: /* nothing to really dissect */ break; default: expert_add_info(pinfo, ti, &ei_cl3dcw_unknown_type); return tvb_captured_length(tvb); } /* now that the individual message dissection functions have ran, update the tree item length so that the hex dissection dieplay highlighting does not include any ethernet frame padding */ proto_item_set_len(ti, total_dcw_message_len); return total_dcw_message_len; /* is this correct ? */ } /* initializes this dissector */ void proto_register_cl3dcw(void) { static hf_register_info hf[] = { { &hf_cl3dcw_type, { "Type", "cl3dcw.type", FT_UINT8, BASE_HEX, VALS(cl3dcw_msg_types), 0x0, NULL, HFILL }}, { &hf_cl3dcw_dccount, { "Data Channel Count", "cl3dcw.dccount", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }}, { &hf_cl3dcw_datamacaddrcount, { "Data MAC Address Count", "cl3dcw.datamacaddrcount", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }}, { &hf_cl3dcw_datassidcount, { "Data SSID Count", "cl3dcw.datassidcount", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }}, { &hf_cl3dcw_dcmacaddr, { "Data Channel MAC Address", "cl3dcw.dcmacaddr", FT_ETHER, BASE_NONE, NULL, 0x0, NULL, HFILL }}, { &hf_cl3dcw_dcssid, { "Data Channel SSID", "cl3dcw.dcssid", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL }}, { &hf_cl3dcw_dcbond, { "Data Channel Bond", "cl3dcw.dcbond", FT_BYTES, SEP_COLON, NULL, 0x0, NULL, HFILL }}, }; static gint *ett[] = { &ett_cl3dcw, &ett_cl3dcw_dcbond, }; static ei_register_info ei[] = { { &ei_cl3dcw_unknown_type, { "cl3dcw.unknown_type", PI_MALFORMED, PI_ERROR, "Unknown DCW message type", EXPFILL }}, { &ei_cl3dcw_nodc, { "cl3dcw.no_data_channels", PI_MALFORMED, PI_WARN, "No data-channels provided", EXPFILL }}, { &ei_cl3dcw_ssid_too_big, { "cl3dcw.ssid_too_big", PI_MALFORMED, PI_WARN, "Data channel SSID too big (expecting 32-byte maximum SSID)", EXPFILL }}, }; expert_module_t* expert_cl3dcw; proto_cl3dcw = proto_register_protocol("CableLabs Dual-Channel Wi-Fi", "cl3dcw", "cl3dcw"); proto_register_field_array(proto_cl3dcw, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); expert_cl3dcw = expert_register_protocol(proto_cl3dcw); expert_register_field_array(expert_cl3dcw, ei, array_length(ei)); cl3dcw_handle = register_dissector("cl3dcw", &dissect_cl3dcw, proto_cl3dcw); } /* hooks in our dissector to be called on matching CL3 (sub-)protocol id */ void proto_reg_handoff_cl3dcw(void) { dissector_add_uint("cl3.subprotocol", 0x00DC, cl3dcw_handle); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 2 * tab-width: 8 * indent-tabs-mode: nil * End: * * vi: set shiftwidth=2 tabstop=8 expandtab: * :indentSize=2:tabSize=8:noTabs=true: */