forked from osmocom/wireshark
FP: Added E-DCH T1 heuristic dissector
Change-Id: I22a3ba4a7caab1e4885292e6d28b2bc3d1e22bb7 Reviewed-on: https://code.wireshark.org/review/30208 Petri-Dish: Anders Broman <a.broman58@gmail.com> Tested-by: Petri Dish Buildbot Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Darien Spencer
Anders Broman
parent
b0759a02bb
commit
c6dc4095b7
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@ -37,7 +37,7 @@
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* - Set the logical channel properly for non multiplexed, channels
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* for channels that doesn't have the C/T field! This should be based
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* on the RRC message RadioBearerSetup.
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* - E-DCH (T1 & T2) heuristic dissectors
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* - E-DCH T2 heuristic dissector
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*/
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void proto_register_fp(void);
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void proto_reg_handoff_fp(void);
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@ -3933,6 +3933,28 @@ check_payload_crc_for_heur(tvbuff_t *tvb, guint16 header_length)
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return calc_crc == crc;
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}
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/* Validates the header CRC in a E-DCH Data FP frame */
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/* Should only be used in heuristic dissectors! */
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static gboolean
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check_edch_header_crc_for_heur(tvbuff_t *tvb, guint16 header_length)
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{
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guint16 crc = 0;
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guint16 calc_crc = 0;
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guint8 * data = NULL;
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if (header_length > tvb_captured_length(tvb))
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return FALSE;
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crc = (tvb_get_bits8(tvb, 0, 7) << 4) + tvb_get_bits8(tvb, 8, 4);
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/* Get data of header excluding the first byte */
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data = (guint8 *)tvb_memdup(wmem_packet_scope(), tvb, 1, header_length-1);
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/*Zero the part in the second byte which contains part of the CRC*/
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data[0] = data[0] & 0x0f;
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calc_crc = crc11_307_noreflect_noxor(data, header_length-1);
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return calc_crc == crc;
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}
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/* Generates a unique 32bit identifier based on the frame's metadata */
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/* This ID is used in the RLC dissector for reassembly */
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/* Should only be used in heuristic dissectors! */
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@ -5000,6 +5022,177 @@ heur_dissect_fp_hsdsch_type_2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tre
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dissect_fp(tvb, pinfo, tree, data);
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return TRUE;
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}
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static gboolean
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heur_dissect_fp_edch_type_1(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
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{
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conversation_t *p_conv;
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umts_fp_conversation_info_t* umts_fp_conversation_info = NULL;
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fp_edch_channel_info_t* fp_edch_channel_info;
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struct fp_info *p_fp_info;
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guint32 captured_length;
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guint8 frame_type;
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guint8 num_sub_frames_byte;
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guint8 number_of_subframes;
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guint8 number_of_mac_es_pdus;
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guint32 subframe_number;
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guint32 total_sub_headers_len;
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guint32 total_header_length;
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guint32 payload_length;
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guint32 total_mac_pdus_count;
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guint32 macd_pdu_bit_size;
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guint32 bit_offset;
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guint32 offset;
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guint32 i = 0;
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guint32 n = 0;
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/* Trying to find existing conversation */
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p_conv = (conversation_t *)find_conversation(pinfo->num, &pinfo->net_dst, &pinfo->net_src,
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conversation_pt_to_endpoint_type(pinfo->ptype),
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pinfo->destport, pinfo->srcport, NO_ADDR_B);
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if (p_conv != NULL) {
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/* Checking if the conversation was already framed */
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umts_fp_conversation_info = (umts_fp_conversation_info_t *)conversation_get_proto_data(p_conv, proto_fp);
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if (umts_fp_conversation_info) {
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fp_edch_channel_info = (fp_edch_channel_info_t*)umts_fp_conversation_info->channel_specific_info;
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if (umts_fp_conversation_info->channel == CHANNEL_EDCH && fp_edch_channel_info->edch_type == 0) {
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conversation_set_dissector(p_conv, fp_handle);
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dissect_fp(tvb, pinfo, tree, data);
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return TRUE;
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}
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else if (umts_fp_conversation_info->channel != CHANNEL_UNKNOWN){
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/* This conversation was successfuly framed as ANOTHER type */
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return FALSE;
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}
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}
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}
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/* Making sure FP info isn't already attached */
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p_fp_info = (fp_info *)p_get_proto_data(wmem_file_scope(), pinfo, proto_fp, 0);
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if (p_fp_info) {
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return FALSE;
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}
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captured_length = tvb_reported_length(tvb);
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/* Lengths limit: header size + at least 1 Subframe Header + CRC Payload size */
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if (captured_length < 9) {
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return FALSE;
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}
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frame_type = tvb_get_guint8(tvb, 0) & 0x01;
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if (frame_type == 1) { /* is 'control' frame type*/
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return FALSE;
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}
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num_sub_frames_byte = tvb_get_guint8(tvb, 2);
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/* Checking 4 leftmost bits in the 'Number of Subframes' byte, which are reserved and should be 0 */
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if (num_sub_frames_byte & 0xf0) {
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return FALSE;
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}
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/* Values {11-16} are reserved */
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number_of_subframes = (num_sub_frames_byte & 0x0f) + 1;
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if (number_of_subframes >= 11) {
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return FALSE;
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}
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/* Iterating through the block headers looking for invalid fields */
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total_header_length = 4;
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offset = 4;
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total_mac_pdus_count = 0;
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/* EDCH subframe header list */
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for (n=0; n < number_of_subframes; n++) {
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/* Making sure the next index is not out of range */
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if (((guint32)(offset + 3)) >= captured_length) {
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return FALSE;
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}
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/* Subframe number */
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subframe_number = (tvb_get_guint8(tvb, offset) & 0x07);
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if (subframe_number > 4) {
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return FALSE;
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}
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offset++;
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/* Number of MAC-es PDUs */
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number_of_mac_es_pdus = (tvb_get_guint8(tvb, offset) & 0xf0) >> 4;
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if (number_of_mac_es_pdus == 0) {
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return FALSE;
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}
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bit_offset = 4;
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/* Making sure enough bytes are presesnt for all sub-header */
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total_sub_headers_len = ((int)((((1.5 + (number_of_mac_es_pdus * 1.5))*8+7)/8)));
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if ((offset + total_sub_headers_len) >= captured_length) {
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return FALSE;
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}
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/* Details of each MAC-es PDU */
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for (i=0; i < number_of_mac_es_pdus; i++) {
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guint32 n_pdus; /*Size of the PDU*/
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/* DDI (6 bits) */
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bit_offset += 6;
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/* Number of MAC-d PDUs (6 bits) */
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n_pdus = tvb_get_bits8( tvb, offset*8 + bit_offset, 6);
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total_mac_pdus_count += n_pdus;
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bit_offset += 6;
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}
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total_header_length += total_sub_headers_len;
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offset += ((bit_offset+7)/8);
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}
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/* Figure MAC bit size */
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payload_length = captured_length - total_header_length - 3; /* Removing 3 bytes for Payload CRC and TSN */
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if (payload_length == (total_mac_pdus_count * 42)) {
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macd_pdu_bit_size = 336;
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}
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else if (payload_length == (total_mac_pdus_count * 18)) {
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macd_pdu_bit_size = 144;
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}
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else {
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/* Unexpected payload length or DDIs combination */
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return FALSE;
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}
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if (!check_edch_header_crc_for_heur(tvb, total_header_length)) {
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return FALSE;
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}
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if (!check_payload_crc_for_heur(tvb, total_header_length)) {
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return FALSE;
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}
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if(!umts_fp_conversation_info) {
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umts_fp_conversation_info = wmem_new0(wmem_file_scope(), umts_fp_conversation_info_t);
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set_both_sides_umts_fp_conv_data(pinfo, umts_fp_conversation_info);
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}
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umts_fp_conversation_info->iface_type = IuB_Interface;
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umts_fp_conversation_info->division = Division_FDD;
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umts_fp_conversation_info->dl_frame_number = pinfo->num;
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umts_fp_conversation_info->ul_frame_number = pinfo->num;
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umts_fp_conversation_info->dch_crc_present = 1;
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umts_fp_conversation_info->com_context_id = generate_ue_id_for_heur(pinfo);
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umts_fp_conversation_info->rlc_mode = FP_RLC_AM;
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copy_address_wmem(wmem_file_scope(), &(umts_fp_conversation_info->crnc_address), &pinfo->src);
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umts_fp_conversation_info->crnc_port = pinfo->srcport;
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umts_fp_conversation_info->channel = CHANNEL_EDCH;
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fp_edch_channel_info = wmem_new0(wmem_file_scope(), fp_edch_channel_info_t);
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fp_edch_channel_info->no_ddi_entries = 0x0f;
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for(i = 0;i<0x0f;i++) {
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fp_edch_channel_info->edch_ddi[i] = i;
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fp_edch_channel_info->edch_macd_pdu_size[i] = macd_pdu_bit_size;
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fp_edch_channel_info->edch_lchId[i] = 9;
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}
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fp_edch_channel_info->edch_type = 0; /* Type 1 */
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umts_fp_conversation_info->channel_specific_info = (void*)fp_edch_channel_info;
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conversation_set_dissector(find_or_create_conversation(pinfo), fp_handle);
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dissect_fp(tvb, pinfo, tree, data);
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return TRUE;
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}
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/* This method can frame UDP streams containing FP packets but dissection of those packets will */
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/* fail since the FP conversation info is never attached */
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/* Usefull for DCH streams containing CS data and don't have their own heuristic method */
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@ -5123,6 +5316,9 @@ heur_dissect_fp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data
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if(match)
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return TRUE;
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match = heur_dissect_fp_hsdsch_type_2(tvb, pinfo, tree, data);
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if(match)
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return TRUE;
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match = heur_dissect_fp_edch_type_1(tvb, pinfo, tree, data);
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if(match)
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return TRUE;
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/* NOTE: Add new heuristic dissectors BEFORE the 'unknown format' dissector */
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