Do desegmentation.
Collapse the two loops through the TCP segment into one.
Use "tvb_reported_length()", not "tvb_length()", to find out how big the
TCP segment is ("tvb_length()" says how much of it was captured, not how
much of it there is).
svn path=/trunk/; revision=4557
This commit is contained in:
Guy Harris
parent
833fd03080
commit
cd172815f6
74
packet-bgp.c
74
packet-bgp.c
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@ -2,7 +2,7 @@
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* Routines for BGP packet dissection.
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* Copyright 1999, Jun-ichiro itojun Hagino <itojun@itojun.org>
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*
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* $Id: packet-bgp.c,v 1.51 2002/01/15 10:12:17 guy Exp $
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* $Id: packet-bgp.c,v 1.52 2002/01/17 09:25:55 guy Exp $
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*
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* Supports:
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* RFC1771 A Border Gateway Protocol 4 (BGP-4)
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@ -67,6 +67,7 @@
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#include "packet-bgp.h"
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#include "packet-ipv6.h"
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#include "afn.h"
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#include "prefs.h"
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static const value_string bgptypevals[] = {
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{ BGP_OPEN, "OPEN Message" },
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@ -238,6 +239,10 @@ static gint ett_bgp_cluster_list = -1; /* cluster list tree */
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static gint ett_bgp_options = -1; /* optional parameters tree */
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static gint ett_bgp_option = -1; /* an optional parameter tree */
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static gint ett_bgp_extended_communities = -1 ; /* extended communities list tree */
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/* desegmentation */
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static gboolean bgp_desegment = TRUE;
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/*
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* Decode an IPv4 prefix.
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*/
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@ -1669,12 +1674,10 @@ dissect_bgp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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if (check_col(pinfo->cinfo, COL_INFO))
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col_clear(pinfo->cinfo, COL_INFO);
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l = tvb_length(tvb);
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l = tvb_reported_length(tvb);
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i = 0;
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found = -1;
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/* run through the TCP packet looking for BGP headers */
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/* this is done twice, but this way each message type can be
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printed in the COL_INFO field */
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while (i + BGP_HEADER_SIZE <= l) {
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tvb_memcpy(tvb, bgp.bgp_marker, i, BGP_HEADER_SIZE);
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@ -1686,6 +1689,27 @@ dissect_bgp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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found++;
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hlen = ntohs(bgp.bgp_len);
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/*
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* Desegmentation check.
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*/
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if (bgp_desegment) {
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if (hlen > tvb_length_remaining(tvb, i) && pinfo->can_desegment) {
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/*
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* Not all of this packet is in the data we've been
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* handed, but we can do reassembly on it.
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*
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* Tell the TCP dissector where the data for
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* this message starts in the data it handed
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* us, and how many more bytes we need, and
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* return.
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*/
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pinfo->desegment_offset = i;
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pinfo->desegment_len = hlen - tvb_length_remaining(tvb, i);
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return;
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}
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}
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typ = val_to_str(bgp.bgp_type, bgptypevals, "Unknown Message");
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if (check_col(pinfo->cinfo, COL_INFO)) {
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@ -1695,35 +1719,12 @@ dissect_bgp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", typ);
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}
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i += hlen;
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}
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if (tree) {
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ti = proto_tree_add_item(tree, proto_bgp, tvb, i, hlen, FALSE);
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bgp_tree = proto_item_add_subtree(ti, ett_bgp);
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if (tree) {
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ti = proto_tree_add_item(tree, proto_bgp, tvb, 0,
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l, FALSE);
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bgp_tree = proto_item_add_subtree(ti, ett_bgp);
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ti = proto_tree_add_text(bgp_tree, tvb, i, hlen, "%s", typ);
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i = 0;
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/* now, run through the TCP packet again, this time dissect */
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/* each message that we find */
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while (i + BGP_HEADER_SIZE <= l) {
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tvb_memcpy(tvb, bgp.bgp_marker, i, BGP_HEADER_SIZE);
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/* look for bgp header */
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if (memcmp(bgp.bgp_marker, marker, sizeof(marker)) != 0) {
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i++;
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continue;
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}
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hlen = ntohs(bgp.bgp_len);
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typ = val_to_str(bgp.bgp_type, bgptypevals, "Unknown Message");
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if (l < hlen) {
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ti = proto_tree_add_text(bgp_tree, tvb, i,
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l, "%s (truncated)", typ);
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} else {
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ti = proto_tree_add_text(bgp_tree, tvb, i, hlen,
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"%s", typ);
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}
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/* add a different tree for each message type */
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switch (bgp.bgp_type) {
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case BGP_OPEN:
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@ -1787,9 +1788,9 @@ dissect_bgp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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default:
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break;
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}
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i += hlen;
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}
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i += hlen;
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}
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}
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@ -1828,11 +1829,18 @@ proto_register_bgp(void)
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&ett_bgp_option,
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&ett_bgp_extended_communities
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};
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module_t *bgp_module;
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proto_bgp = proto_register_protocol("Border Gateway Protocol",
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"BGP", "bgp");
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proto_register_field_array(proto_bgp, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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bgp_module = prefs_register_protocol(proto_bgp, NULL);
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prefs_register_bool_preference(bgp_module, "desegment",
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"Desegment all BGP messages spanning multiple TCP segments",
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"Whether the BGP dissector should desegment all messages spanning multiple TCP segments",
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&bgp_desegment);
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}
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void
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