forked from osmocom/wireshark
359 lines
13 KiB
C
359 lines
13 KiB
C
![]() |
/* packet-cl3dcw.c
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* Routines for CableLabs Dual-Channel Wi-Fi Messaging Protocol Dissection
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* Copyright 2019 Jon Dennis <j.dennis[at]cablelabs.com>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*
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* CableLabs Specifications Can Be Found At:
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* https://www.cablelabs.com/specs
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/expert.h>
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void proto_register_cl3dcw(void);
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void proto_reg_handoff_cl3dcw(void);
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#define SSID_MAX_LENGTH 32
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/* persistent handles for this dissector */
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static int proto_cl3dcw = -1;
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static gint ett_cl3dcw = -1;
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static int hf_cl3dcw_type = -1;
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static int hf_cl3dcw_dccount = -1;
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static int hf_cl3dcw_datamacaddrcount = -1;
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static int hf_cl3dcw_datassidcount = -1;
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static int hf_cl3dcw_pcmacaddr = -1;
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static int hf_cl3dcw_dcmacaddr = -1;
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static int hf_cl3dcw_dcssid = -1;
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static int hf_cl3dcw_dcbond = -1;
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static gint ett_cl3dcw_dcbond = -1;
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static expert_field ei_cl3dcw_unknown_type = EI_INIT;
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static expert_field ei_cl3dcw_nodc = EI_INIT;
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static expert_field ei_cl3dcw_ssid_too_big = EI_INIT;
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/* message id types */
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#define DCWMSG_STA_JOIN 0x01
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#define DCWMSG_STA_UNJOIN 0x02
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#define DCWMSG_STA_ACK 0x11
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#define DCWMSG_STA_NACK 0x12
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#define DCWMSG_AP_ACCEPT_STA 0x21
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#define DCWMSG_AP_REJECT_STA 0x22
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#define DCWMSG_AP_ACK_DISCONNECT 0x41
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#define DCWMSG_AP_QUIT 0x99
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/* message type strings */
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static const value_string cl3dcw_msg_types[] = {
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{DCWMSG_STA_JOIN, "Station Join" },
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{DCWMSG_STA_UNJOIN, "Station Unjoin" },
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{DCWMSG_STA_ACK, "Station Ack" },
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{DCWMSG_STA_NACK, "Station Nack" },
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{DCWMSG_AP_ACCEPT_STA, "AP Accept Station" },
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{DCWMSG_AP_REJECT_STA, "AP Reject Station" },
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{DCWMSG_AP_ACK_DISCONNECT, "AP Ack Disconnect" },
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{DCWMSG_AP_QUIT, "AQ Quit" },
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{0, NULL}
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};
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static gint
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dissect_sta_join(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) {
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guint32 data_macaddr_count;
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gint offset;
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proto_tree_add_item_ret_uint(tree, hf_cl3dcw_datamacaddrcount, tvb, 0, 1, ENC_NA, &data_macaddr_count);
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if (data_macaddr_count < 1) {
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expert_add_info(pinfo, ti, &ei_cl3dcw_nodc);
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}
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offset = 1;
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while(data_macaddr_count--) {
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proto_tree_add_item(tree, hf_cl3dcw_dcmacaddr, tvb, offset, 6, ENC_NA);
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offset += 6;
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}
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return offset;
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}
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static gint
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dissect_sta_unjoin(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) {
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guint32 data_macaddr_count;
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gint offset;
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proto_tree_add_item_ret_uint(tree, hf_cl3dcw_datamacaddrcount, tvb, 0, 1, ENC_NA, &data_macaddr_count);
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if (data_macaddr_count < 1) {
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expert_add_info(pinfo, ti, &ei_cl3dcw_nodc);
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}
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offset = 1;
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while (data_macaddr_count--) {
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proto_tree_add_item(tree, hf_cl3dcw_dcmacaddr, tvb, offset, 6, ENC_NA);
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offset += 6;
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}
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return offset;
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}
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static gint
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dissect_sta_ack(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) {
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proto_item *bond_item;
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proto_tree *bond_tree;
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guint32 data_channel_count;
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guint8 ssid_len;
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guint8 *ssidbuf;
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gint offset;
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proto_tree_add_item_ret_uint(tree, hf_cl3dcw_dccount, tvb, 0, 1, ENC_NA, &data_channel_count);
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if (data_channel_count < 1) {
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expert_add_info(pinfo, ti, &ei_cl3dcw_nodc);
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}
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offset = 1;
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while (data_channel_count--) {
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/* parse each data channel bond...
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* format is 6-byte mac addr + 1 byte ssid string length + ssid string
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*/
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ssid_len = tvb_get_guint8(tvb, offset + 6); /* +6 = skip over mac address */
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if (ssid_len > SSID_MAX_LENGTH) {
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expert_add_info(pinfo, ti, &ei_cl3dcw_ssid_too_big);
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}
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ssidbuf = tvb_get_string_enc(wmem_packet_scope(), tvb, offset + 6 + 1, ssid_len, ENC_ASCII); /* +6+1 = skip over mac address and length field */
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/* add the data channel bond sub-tree item */
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bond_item = proto_tree_add_item(tree, hf_cl3dcw_dcbond, tvb, offset, 6, ENC_NA);
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proto_item_append_text(bond_item, " -> \"%.*s\"", (guint)ssid_len, ssidbuf);
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proto_item_set_len(bond_item, 6 + 1 + ssid_len);
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bond_tree = proto_item_add_subtree(bond_item, ett_cl3dcw_dcbond);
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/* add the MAC address... */
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proto_tree_add_item(bond_tree, hf_cl3dcw_dcmacaddr, tvb, offset, 6, ENC_NA);
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offset += 6;
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/* add the SSID string
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* XXX the intent here is to highlight the leading length byte in the hex dump
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* without printing it in the string... i suspect there is a better way of doing this
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*/
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proto_tree_add_string_format(bond_tree, hf_cl3dcw_dcssid, tvb, offset, 1 + ssid_len,
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"", "Data Channel SSID: %.*s",
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(guint)ssid_len, ssidbuf);
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offset += 1 + ssid_len;
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}
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return offset;
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}
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static gint
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dissect_sta_nack(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) {
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guint32 data_macaddr_count;
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gint offset;
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proto_tree_add_item_ret_uint(tree, hf_cl3dcw_datamacaddrcount, tvb, 0, 1, ENC_NA, &data_macaddr_count);
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if (data_macaddr_count < 1) {
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expert_add_info(pinfo, ti, &ei_cl3dcw_nodc);
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}
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offset = 1;
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while (data_macaddr_count--) {
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proto_tree_add_item(tree, hf_cl3dcw_dcmacaddr, tvb, offset, 6, ENC_NA);
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offset += 6;
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}
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return offset;
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}
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static gint
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dissect_ap_accept_sta(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) {
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guint32 data_ssid_count;
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guint8 ssid_len;
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guint8 *ssidbuf;
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gint offset;
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proto_tree_add_item_ret_uint(tree, hf_cl3dcw_datassidcount, tvb, 0, 1, ENC_NA, &data_ssid_count);
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if (data_ssid_count < 1) {
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expert_add_info(pinfo, ti, &ei_cl3dcw_nodc);
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}
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offset = 1;
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while (data_ssid_count--) {
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ssid_len = tvb_get_guint8(tvb, offset);
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if (ssid_len > SSID_MAX_LENGTH) {
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expert_add_info(pinfo, ti, &ei_cl3dcw_ssid_too_big);
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}
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ssidbuf = tvb_get_string_enc(wmem_packet_scope(), tvb, offset + 1, ssid_len, ENC_ASCII); /* +1 = skip over length field */
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/* add the SSID string
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* XXX the intent here is to highlight the leading length byte in the hex dump
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* without printing it in the string... i suspect there is a better way of doing this
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*/
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proto_tree_add_string_format(tree, hf_cl3dcw_dcssid, tvb, offset, 1 + ssid_len,
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"", "Data Channel SSID: %.*s",
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(guint)ssid_len, ssidbuf);
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offset += 1 + ssid_len;
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}
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return offset;
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}
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static gint
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dissect_ap_reject_sta(tvbuff_t * const tvb, packet_info * const pinfo, proto_tree * const tree _U_, proto_item * const ti) {
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guint32 data_macaddr_count;
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gint offset;
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proto_tree_add_item_ret_uint(tree, hf_cl3dcw_datamacaddrcount, tvb, 0, 1, ENC_NA, &data_macaddr_count);
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if (data_macaddr_count < 1) {
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expert_add_info(pinfo, ti, &ei_cl3dcw_nodc);
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}
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offset = 1;
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while (data_macaddr_count--) {
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proto_tree_add_item(tree, hf_cl3dcw_dcmacaddr, tvb, offset, 6, ENC_NA);
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offset += 6;
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}
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return offset;
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}
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/* called for each incomming framing matching our CL3 (sub-)protocol id: */
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static int
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dissect_cl3dcw(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree _U_, void *data _U_) {
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proto_item *ti;
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proto_tree *cl3dcw_tree;
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tvbuff_t *tvb_msg;
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gint total_dcw_message_len;
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guint8 type;
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/* parse the header fields */
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total_dcw_message_len = 1;
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type = tvb_get_guint8(tvb, 0);
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/* setup the "packet summary view" fields */
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "CL3-DCW");
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col_clear(pinfo->cinfo, COL_INFO);
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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);
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/* create a tree node for us... */
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ti = proto_tree_add_protocol_format(tree, proto_cl3dcw, tvb, 0, tvb_captured_length(tvb), "Dual-Channel Wi-Fi Control Message");
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cl3dcw_tree = proto_item_add_subtree(ti, ett_cl3dcw);
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tvb_msg = tvb_new_subset_remaining(tvb, 1);
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/* display dcw fields: */
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proto_tree_add_uint(cl3dcw_tree, hf_cl3dcw_type, tvb, 0, 1, type);
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/* parse the message by type... */
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switch (type) {
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case DCWMSG_STA_JOIN: total_dcw_message_len += dissect_sta_join(tvb_msg, pinfo, cl3dcw_tree, ti); break;
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case DCWMSG_STA_UNJOIN: total_dcw_message_len += dissect_sta_unjoin(tvb_msg, pinfo, cl3dcw_tree, ti); break;
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case DCWMSG_STA_ACK: total_dcw_message_len += dissect_sta_ack(tvb_msg, pinfo, cl3dcw_tree, ti); break;
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case DCWMSG_STA_NACK: total_dcw_message_len += dissect_sta_nack(tvb_msg, pinfo, cl3dcw_tree, ti); break;
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case DCWMSG_AP_ACCEPT_STA: total_dcw_message_len += dissect_ap_accept_sta(tvb_msg, pinfo, cl3dcw_tree, ti); break;
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case DCWMSG_AP_REJECT_STA: total_dcw_message_len += dissect_ap_reject_sta(tvb_msg, pinfo, cl3dcw_tree, ti); break;
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case DCWMSG_AP_ACK_DISCONNECT: /* nothing to really dissect */ break;
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case DCWMSG_AP_QUIT: /* nothing to really dissect */ break;
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default:
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expert_add_info(pinfo, ti, &ei_cl3dcw_unknown_type);
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return tvb_captured_length(tvb);
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}
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/* now that the individual message dissection functions have ran,
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update the tree item length so that the hex dissection dieplay
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highlighting does not include any ethernet frame padding */
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proto_item_set_len(ti, total_dcw_message_len);
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return total_dcw_message_len; /* is this correct ? */
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}
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/* initializes this dissector */
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void
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proto_register_cl3dcw(void) {
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static hf_register_info hf[] = {
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{ &hf_cl3dcw_type,
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{ "Type", "cl3dcw.type",
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FT_UINT8, BASE_HEX, VALS(cl3dcw_msg_types), 0x0,
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NULL, HFILL }},
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{ &hf_cl3dcw_dccount,
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{ "Data Channel Count", "cl3dcw.dccount",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_cl3dcw_datamacaddrcount,
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{ "Data MAC Address Count", "cl3dcw.datamacaddrcount",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_cl3dcw_datassidcount,
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{ "Data SSID Count", "cl3dcw.datassidcount",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_cl3dcw_pcmacaddr,
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{ "Primary Channel MAC Address", "cl3dcw.pcmacaddr",
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FT_ETHER, BASE_NONE, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_cl3dcw_dcmacaddr,
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{ "Data Channel MAC Address", "cl3dcw.dcmacaddr",
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FT_ETHER, BASE_NONE, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_cl3dcw_dcssid,
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{ "Data Channel SSID", "cl3dcw.dcssid",
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FT_STRING, BASE_NONE, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_cl3dcw_dcbond,
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{ "Data Channel Bond", "cl3dcw.dcbond",
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FT_BYTES, SEP_COLON, NULL, 0x0,
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NULL, HFILL }},
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};
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static gint *ett[] = {
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&ett_cl3dcw,
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&ett_cl3dcw_dcbond,
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};
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static ei_register_info ei[] = {
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{ &ei_cl3dcw_unknown_type, { "cl3dcw.unknown_type", PI_MALFORMED, PI_ERROR, "Unknown DCW message type", EXPFILL }},
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{ &ei_cl3dcw_nodc, { "cl3dcw.no_data_channels", PI_MALFORMED, PI_WARN, "No data-channels provided", EXPFILL }},
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{ &ei_cl3dcw_ssid_too_big, { "cl3dcw.ssid_too_big", PI_MALFORMED, PI_WARN, "Data channel SSID too big (expecting 32-byte maximum SSID)", EXPFILL }},
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};
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expert_module_t* expert_cl3dcw;
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proto_cl3dcw = proto_register_protocol(
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"CableLabs Dual-Channel Wi-Fi", /* name */
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"cl3dcw", /* short name */
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"cl3dcw" /* abbrev */
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);
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proto_register_field_array(proto_cl3dcw, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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expert_cl3dcw = expert_register_protocol(proto_cl3dcw);
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expert_register_field_array(expert_cl3dcw, ei, array_length(ei));
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}
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/* hooks in our dissector to be called on matching CL3 (sub-)protocol id */
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void
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proto_reg_handoff_cl3dcw(void) {
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dissector_handle_t cl3dcw_handle;
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cl3dcw_handle = create_dissector_handle(&dissect_cl3dcw, proto_cl3dcw);
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dissector_add_uint("cl3.subprotocol", 0x00DC, cl3dcw_handle);
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 2
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=2 tabstop=8 expandtab:
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* :indentSize=2:tabSize=8:noTabs=true:
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*/
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