Wireshark mailing list archives
Re: Parse CFM Type Test signal (TST) without CRC
From: Pascal Quantin <pascal.quantin () gmail com>
Date: Tue, 16 Jun 2015 18:43:35 +0200
Le 16 juin 2015 4:14 PM, "Jiunrong" <jiunrong () gmail com> a écrit :
Hi advancer: I found [Malformed Packet: CFM] when I receive CFM Type Test signal (TST)
without CRC32, but it is ok with CRC32.
I try to find what happen, so I download the source code. I am new guide in wireshark, if I make mistake, please don’t laugh me. in file: epan/dissectors/packet-cfm.c Due to tlv_data_offset += (cfm_tlv_length-5); I think next line maybe need -1 tlv_data_offset += cfm_tlv_length; //maybe it need -1 if (cfm_tlv_length > 0) { switch (tlv_tst_test_pattern_type) { case 0: case 2: proto_tree_add_item(cfm_tlv_tree, hf_tlv_tst_test_pattern, tvb, tlv_data_offset, cfm_tlv_length-1,
ENC_NA);
tlv_data_offset += cfm_tlv_length; //maybe it need -1 break; case 1: case 3: proto_tree_add_item(cfm_tlv_tree, hf_tlv_tst_test_pattern, tvb, tlv_data_offset, cfm_tlv_length-5, ENC_NA); tlv_data_offset += (cfm_tlv_length-5); proto_tree_add_item(cfm_tlv_tree, hf_tlv_tst_CRC32, tvb, tlv_data_offset, 4, ENC_NA); tlv_data_offset += 4; break; } } From JustinKu
Hi JustinKu, Can I convince you to fill a bug on http://bugs.wireshark.org with your pcap file triggering the malformed message attached? Best regards, Pascal.
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Current thread:
- Parse CFM Type Test signal (TST) without CRC Jiunrong (Jun 16)
- Re: Parse CFM Type Test signal (TST) without CRC Pascal Quantin (Jun 16)