diff options
| author | jake <jake@f5534014-38df-0310-8fa8-9805f1628bb7> | 2010-06-20 14:37:34 +0000 |
|---|---|---|
| committer | jake <jake@f5534014-38df-0310-8fa8-9805f1628bb7> | 2010-06-20 14:37:34 +0000 |
| commit | b8040367633e5dfad005bca0105ee0e68c96f6c9 (patch) | |
| tree | 3a332c773f1287276f1225b9558e29d5cf594c9a /epan/dissectors/packet-gsm_ipa.c | |
| parent | ea1c236fe981bf363ab1efb9675da9a287099028 (diff) | |
From Holger Freyther:
The current implementation assumes that the IPA protocol header is three byte.
This is true for TCP but not for packets sent over UDP, which uses four bytes.
From me:
Improve heuristic and offset tracking.
git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@33259 f5534014-38df-0310-8fa8-9805f1628bb7
Diffstat (limited to 'epan/dissectors/packet-gsm_ipa.c')
| -rw-r--r-- | epan/dissectors/packet-gsm_ipa.c | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/epan/dissectors/packet-gsm_ipa.c b/epan/dissectors/packet-gsm_ipa.c index bcd987febf..11b80502c5 100644 --- a/epan/dissectors/packet-gsm_ipa.c +++ b/epan/dissectors/packet-gsm_ipa.c @@ -1,7 +1,7 @@ /* packet-gsm_ipa.c * Routines for packet dissection of ip.access GSM over IP * Copyright 2009 by Harald Welte <laforge@gnumonks.org> - * Copyright 2009 by Holger Hans Peter Freyther <zecke@selfish.org> + * Copyright 2009, 2010 by Holger Hans Peter Freyther <zecke@selfish.org> * * $Id$ * @@ -31,6 +31,7 @@ #include <glib.h> #include <epan/packet.h> +#include <epan/ipproto.h> /* Initialize the protocol and registered fields */ static int proto_ipa = -1; @@ -171,13 +172,14 @@ dissect_ipaccess(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) static void dissect_ipa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { - + gint remaining; + gint header_length = 3; int offset = 0; col_set_str(pinfo->cinfo, COL_PROTOCOL, "IPA"); col_clear(pinfo->cinfo, COL_INFO); - while (tvb_reported_length_remaining(tvb, offset) > 0) { + while ((remaining = tvb_reported_length_remaining(tvb, offset)) > 0) { proto_item *ti; proto_tree *ipa_tree; guint16 len, msg_type; @@ -190,20 +192,30 @@ dissect_ipa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) val_to_str(msg_type, ipa_protocol_vals, "unknown 0x%02x")); + /* + * The IPA header is different depending on the transport protocol. + * With UDP there seems to be a fourth byte for the IPA header. + * We attempt to detect this by checking if the length from the + * header + four bytes of the IPA header equals the remaining size. + */ + if ((pinfo->ipproto == IP_PROTO_UDP) && (len + 4 == remaining)) { + header_length++; + } + if (tree) { ti = proto_tree_add_protocol_format(tree, proto_ipa, - tvb, offset, len+3, + tvb, offset, len+header_length, "IPA protocol ip.access, type: %s", val_to_str(msg_type, ipa_protocol_vals, "unknown 0x%02x")); ipa_tree = proto_item_add_subtree(ti, ett_ipa); proto_tree_add_item(ipa_tree, hf_ipa_data_len, - tvb, offset+1, 1, FALSE); + tvb, offset, 2, FALSE); proto_tree_add_item(ipa_tree, hf_ipa_protocol, tvb, offset+2, 1, FALSE); } - next_tvb = tvb_new_subset(tvb, offset+3, len, len); + next_tvb = tvb_new_subset(tvb, offset+header_length, len, len); switch (msg_type) { case ABISIP_OML: @@ -226,7 +238,7 @@ dissect_ipa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) } break; } - offset += len + 3; + offset += len + header_length; } } @@ -235,7 +247,7 @@ void proto_register_ipa(void) static hf_register_info hf[] = { {&hf_ipa_data_len, {"DataLen", "ipa.data_len", - FT_UINT8, BASE_DEC, NULL, 0x0, + FT_UINT16, BASE_DEC, NULL, 0x0, "The length of the data (in bytes)", HFILL} }, {&hf_ipa_protocol, |