forked from osmocom/wireshark
Fix in CRC checker for FPP
fix in the computation of CRC + little change in the dissector - now it shows the fields SMD and FRAG_COUNT in the tree correctly Bug: 14610 Change-Id: I74982ff836f02803843f6b44a0955a4b20f48e43 Reviewed-on: https://code.wireshark.org/review/28286 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:
Erika Szelleova
Anders Broman
parent
c678cf8a6a
commit
2bac238efb
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@ -30,8 +30,8 @@ static int proto_fpp = -1;
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static dissector_handle_t fpp_handle;
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static int hf_fpp_preamble = -1;
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static int hf_fpp_preamble_seventh = -1;
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static int hf_fpp_preamble_eight = -1;
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static int hf_fpp_preamble_smd = -1;
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static int hf_fpp_preamble_frag_count = -1;
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static int hf_fpp_mdata = -1;
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static int hf_fpp_crc32 = -1;
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static int hf_fpp_crc32_status = -1;
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@ -164,12 +164,14 @@ static const value_string frag_count_delim_desc[] = {
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static fpp_crc_t
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get_crc_stat(tvbuff_t *tvb, guint32 crc, guint32 mcrc) {
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fpp_crc_t crc_val;
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if (tvb_get_guint32(tvb, tvb_reported_length(tvb) - FPP_CRC_LENGTH, ENC_BIG_ENDIAN) == crc) {
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crc_val = CRC_CRC;
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} else if (tvb_get_guint32(tvb, tvb_reported_length(tvb) - FPP_CRC_LENGTH, ENC_BIG_ENDIAN) == mcrc) {
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crc_val = CRC_mCRC;
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guint32 received_crc = tvb_get_guint32(tvb, tvb_reported_length(tvb) - FPP_CRC_LENGTH, ENC_BIG_ENDIAN);
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if (received_crc == crc) {
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crc_val = CRC_CRC;
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} else if (received_crc == mcrc) {
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crc_val = CRC_mCRC;
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} else {
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crc_val = CRC_FALSE;
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crc_val = CRC_FALSE;
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}
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return crc_val;
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}
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@ -313,8 +315,11 @@ dissect_preemption(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32
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guint8 smd1 = tvb_get_guint8(tvb, 6);
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guint8 smd2 = tvb_get_guint8(tvb, 7);
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guint32 mcrc = crc ^ 0xffff0000;
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guint crc_offset = tvb_reported_length(tvb) - FPP_CRC_LENGTH;
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gint frag_size = tvb_reported_length(tvb) - FPP_PREAMBLE_LENGTH - FPP_CRC_LENGTH;
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/* Reassembly parameters. */
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tvbuff_t *new_tvb = NULL;
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fragment_head *frag_data;
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@ -333,8 +338,16 @@ dissect_preemption(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32
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proto_tree_add_item(tree, hf_fpp_mdata, tvb, FPP_PREAMBLE_LENGTH, frag_size, ENC_NA);
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proto_tree *fpp_preamble_tree = proto_item_add_subtree(ti_preamble, ett_fpp_preamble);
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proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_seventh, tvb, 6, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_eight, tvb, 7, 1, ENC_BIG_ENDIAN);
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if(get_packet_type(tvb) == FPP_Packet_Cont)
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{
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proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_smd, tvb, 6, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_frag_count, tvb, 7, 1, ENC_BIG_ENDIAN);
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}
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else
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{
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proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_smd, tvb, 7, 1, ENC_BIG_ENDIAN);
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}
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pck_type = get_packet_type(tvb);
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if (pck_type == FPP_Packet_Init) {
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@ -371,7 +384,7 @@ dissect_preemption(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32
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set_address_tvb(&pinfo->dl_src, AT_ETHER, 6, tvb, 14);
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set_address_tvb(&pinfo->src, AT_ETHER, 6, tvb, 14);
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, mcrc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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} else {
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/* Invalid packet */
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drop_fragments(pinfo);
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@ -380,7 +393,7 @@ dissect_preemption(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32
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drop_conversation(conv);
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}
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, mcrc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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}
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} else if (pck_type == FPP_Packet_Cont) {
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if (crc_val == CRC_mCRC) {
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@ -410,7 +423,7 @@ dissect_preemption(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32
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drop_fragments(pinfo);
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}
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, mcrc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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} else {
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/* Suppose that the last fragment dissected
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1. preemption is active
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@ -442,12 +455,12 @@ dissect_preemption(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32
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pinfo->fragmented = save_fragmented;
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} else {
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drop_fragments(pinfo);
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, mcrc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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}
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if (new_tvb) {
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/* Reassembly was successful; return the completed datagram. */
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guint32 reassembled_crc = crc32_ccitt_tvb_offset(new_tvb, 0, tvb_reported_length(new_tvb));
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guint32 reassembled_crc = GUINT32_SWAP_LE_BE(crc32_ccitt_tvb_offset(new_tvb, 0, tvb_reported_length(new_tvb)));
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/* Reassembly frame takes place regardless of whether the check sum was correct or not. */
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_crc32, -1, &ei_fpp_crc32, pinfo, reassembled_crc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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@ -461,9 +474,9 @@ dissect_preemption(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32
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}
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}
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} else if (pck_type == FPP_Packet_Verify) {
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, -1, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, -1, &ei_fpp_mcrc32, pinfo, mcrc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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} else if (pck_type == FPP_Packet_Response) {
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, mcrc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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}
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return NULL;
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@ -482,8 +495,7 @@ dissect_express(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32 crc
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proto_tree_add_item(tree, hf_fpp_mdata, tvb, offset, pdu_data_len, ENC_NA);
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proto_tree *fpp_preamble_tree = proto_item_add_subtree(ti_preamble, ett_fpp_preamble);
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proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_seventh, tvb, 6, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_eight, tvb, 7, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_smd, tvb, 7, 1, ENC_BIG_ENDIAN);
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proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_crc32, hf_fpp_crc32_status, &ei_fpp_crc32, pinfo, crc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
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@ -504,7 +516,7 @@ dissect_fpp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "FPP");
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col_clear(pinfo->cinfo,COL_INFO);
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crc = crc32_ccitt_tvb_offset(tvb, FPP_PREAMBLE_LENGTH, pdu_data_len);
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crc = GUINT32_SWAP_LE_BE(crc32_ccitt_tvb_offset(tvb, FPP_PREAMBLE_LENGTH, pdu_data_len));
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mcrc = crc ^ 0xffff0000;
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// get crc type
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@ -550,14 +562,14 @@ proto_register_fpp(void)
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NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_fpp_preamble_seventh,
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{ "Seventh", "fpp.preamble.seventh",
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{ &hf_fpp_preamble_smd,
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{ "SMD", "fpp.preamble.smd",
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FT_UINT8, BASE_HEX,
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NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_fpp_preamble_eight,
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{ "Eight", "fpp.preamble.eight",
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{ &hf_fpp_preamble_frag_count,
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{ "Fragment count", "fpp.preamble.frag_count",
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FT_UINT8, BASE_HEX,
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NULL, 0x0,
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NULL, HFILL }
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