diff options
| author | Alexis La Goutte <alexis.lagoutte@gmail.com> | 2013-02-21 10:50:28 +0000 |
|---|---|---|
| committer | Alexis La Goutte <alexis.lagoutte@gmail.com> | 2013-02-21 10:50:28 +0000 |
| commit | d2b0c28f71f3f195b411823982966d40dedd7892 (patch) | |
| tree | fe8617cafb410d7bc057b12615652f438b009f24 /epan/dissectors/packet-capwap.c | |
| parent | a7b6cf24e7fa7320aeabc355207fe5fccecfe707 (diff) | |
From Paul via https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=8319 CAPWAP Header dissector returns invalid length
The problem is when Wireshark dissect CAPWAP packets from Cisco without preference "Cisco Wireless Controller Support"
In this case the whole packet decoded wrong, not only Wireless Specific Information field in CAPWAP header
I suggest following patch to dissect_capwap_header function to always return correct length of CAPWAP header based on HLEN header field
From me:
Add expert info to display a warning about Calculate length and Header length are different (and suggest to activate Cisco Wireless Controller Support Preference)
svn path=/trunk/; revision=47793
Diffstat (limited to 'epan/dissectors/packet-capwap.c')
| -rw-r--r-- | epan/dissectors/packet-capwap.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/epan/dissectors/packet-capwap.c b/epan/dissectors/packet-capwap.c index 2b4aff59ac..98c662b669 100644 --- a/epan/dissectors/packet-capwap.c +++ b/epan/dissectors/packet-capwap.c @@ -30,6 +30,7 @@ #include <epan/packet.h> #include <epan/prefs.h> #include <epan/reassemble.h> +#include <epan/expert.h> #include <epan/sminmpec.h> @@ -1195,8 +1196,8 @@ dissect_capwap_control_header(tvbuff_t *tvb, proto_tree *capwap_control_tree, gu static int dissect_capwap_header(tvbuff_t *tvb, proto_tree *capwap_control_tree, guint offset, packet_info *pinfo, guint8 *payload_type, guint8 *payload_wbid, gboolean *fragment_is, gboolean *fragment_more, guint32 *fragment_id, guint32 *fragment_offset) { - guint plen = 0; - proto_item *ti, *ti_flag; + guint plen = 0, hlen = 0; + proto_item *ti, *ti_flag, *ti_len; proto_tree *capwap_header_tree; proto_tree *capwap_header_flags_tree; guint flags = 0; @@ -1205,11 +1206,13 @@ dissect_capwap_header(tvbuff_t *tvb, proto_tree *capwap_control_tree, guint offs /* RFC 5415 HLEN: A 5-bit field containing the length of the CAPWAP transport header in 4-byte words */ /* As we display the preamble separately reduce the length by 1 */ - ti = proto_tree_add_item(capwap_control_tree, hf_capwap_header, tvb, offset+plen, ((tvb_get_bits8(tvb, (offset+plen)*8, 5))*4)-1, ENC_NA); + hlen = tvb_get_bits8(tvb, (offset+plen)*8, 5)*4-1; + ti = proto_tree_add_item(capwap_control_tree, hf_capwap_header, tvb, offset+plen, hlen, ENC_NA); capwap_header_tree = proto_item_add_subtree(ti, ett_capwap); /* Header Length : 5 Bits */ - proto_tree_add_uint(capwap_header_tree, hf_capwap_header_hlen, tvb, offset+plen, 1, tvb_get_bits8(tvb, (offset+plen)*8, 5)); + ti_len = proto_tree_add_uint(capwap_header_tree, hf_capwap_header_hlen, tvb, offset+plen, 1, tvb_get_bits8(tvb, (offset+plen)*8, 5)); + proto_item_append_text(ti_len, " (%d)",hlen+1); /* Radio ID : 5 Bits */ proto_tree_add_uint(capwap_header_tree, hf_capwap_header_rid, tvb, offset+plen, 1, tvb_get_bits8(tvb, (offset+plen)*8+5, 5)); @@ -1306,7 +1309,11 @@ dissect_capwap_header(tvbuff_t *tvb, proto_tree *capwap_control_tree, guint offs plen += align; } } - return plen; + if ((plen != hlen) && global_capwap_draft_8_cisco == 0) + { + expert_add_info_format(pinfo, ti_len, PI_MALFORMED, PI_WARN, "Wrong calculate length (%d) =! header length (%d) ! (May be try to use Cisco Wireless Controller Support Preference ?)", plen, hlen); + } + return hlen; } /* Returns the number of bytes consumed by this option. */ @@ -1553,7 +1560,7 @@ proto_register_capwap_control(void) { &hf_capwap_header_hlen, { "Header Length", "capwap.header.length", FT_UINT8, BASE_DEC, NULL, 0x0, - NULL, HFILL }}, + "Length of the CAPWAP transport header in 4-byte words (similar to IP header length) ", HFILL }}, { &hf_capwap_header_rid, { "Radio ID", "capwap.header.rid", FT_UINT8, BASE_DEC, NULL, 0x0, |