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The decision on whether there's an encapsulated IP packet in a 

Source-Active TLV should be based on the length of the Source-Active
TLV, not on the length of the data remaining in the tvbuff.

The length of an (S,G) block is 12 bytes, not 24 bytes.

svn path=/trunk/; revision=6943
This commit is contained in:
Guy Harris 2003-01-20 06:24:37 +00:00
parent 6c4a845613
commit c091bb397d
1 changed files with 48 additions and 13 deletions
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61
packet-msdp.c
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@ -4,7 +4,7 @@
*
* Copyright 2001, Heikki Vatiainen <hessu@cs.tut.fi>
*
* $Id: packet-msdp.c,v 1.7 2002/08/02 23:35:54 jmayer Exp $
* $Id: packet-msdp.c,v 1.8 2003/01/20 06:24:37 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
@ -169,7 +169,8 @@ static dissector_handle_t ip_handle;
static void
dissect_msdp_sa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int *offset);
dissect_msdp_sa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
int *offset, int len);
static void
dissect_msdp_notification(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int *offset, guint16 tlv_len);
@ -205,11 +206,13 @@ dissect_msdp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
proto_tree_add_uint(msdp_tree, hf_msdp_type, tvb, offset, 1, type);
proto_tree_add_uint(msdp_tree, hf_msdp_length, tvb, offset + 1, 2, length);
offset += 3;
length -= 3;
switch (type) {
case MSDP_SA:
case MSDP_SA_RSP:
dissect_msdp_sa(tvb, pinfo, msdp_tree, &offset);
dissect_msdp_sa(tvb, pinfo, msdp_tree, &offset,
length);
break;
case MSDP_SA_REQ:
proto_tree_add_item(msdp_tree, hf_msdp_sa_req_res, tvb, offset, 1, FALSE);
@ -220,9 +223,9 @@ dissect_msdp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
dissect_msdp_notification(tvb, pinfo, msdp_tree, &offset, length);
break;
default:
if (length > 3)
proto_tree_add_text(msdp_tree, tvb, offset, length - 3, "TLV contents");
offset += (length - 3);
if (length > 0)
proto_tree_add_text(msdp_tree, tvb, offset, length, "TLV contents");
offset += length;
break;
}
}
@ -239,18 +242,28 @@ dissect_msdp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
* with one exception. Encapsulated multicast data is not allowed in
* SA Response.
*/
static void dissect_msdp_sa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int *offset)
static void dissect_msdp_sa(tvbuff_t *tvb, packet_info *pinfo,
proto_tree *tree, int *offset, int length)
{
guint8 entries;
guint32 rp_addr;
if (length < 1)
return;
entries = tvb_get_guint8(tvb, *offset);
proto_tree_add_uint(tree, hf_msdp_sa_entry_count, tvb, *offset, 1, entries);
*offset += 1;
length -= 1;
if (length < 4) {
*offset += length;
length = 0;
return;
}
tvb_memcpy(tvb, (guint8 *)&rp_addr, *offset, 4);
proto_tree_add_item(tree, hf_msdp_sa_rp_addr, tvb, *offset, 4, FALSE);
*offset += 4;
length -= 4;
/* Put each of the (S,G) entries in their own subtree.
* This is probably visually better.
@ -259,7 +272,12 @@ static void dissect_msdp_sa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
proto_item *ei;
proto_tree *entry_tree;
ei = proto_tree_add_text(tree, tvb, *offset, 24, "(S,G) block: %s/%u -> %s",
if (length < 12) {
*offset += length;
length = 0;
return;
}
ei = proto_tree_add_text(tree, tvb, *offset, 12, "(S,G) block: %s/%u -> %s",
ip_to_str(tvb_get_ptr(tvb, *offset + 8, 4)),
tvb_get_guint8(tvb, *offset + 3),
ip_to_str(tvb_get_ptr(tvb, *offset + 4, 4)));
@ -267,28 +285,45 @@ static void dissect_msdp_sa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
proto_tree_add_item(entry_tree, hf_msdp_sa_reserved, tvb, *offset, 3, FALSE);
*offset += 3;
length -= 3;
proto_tree_add_item(entry_tree, hf_msdp_sa_sprefix_len, tvb, *offset, 1, FALSE);
*offset += 1;
length -= 1;
proto_tree_add_item(entry_tree, hf_msdp_sa_group_addr, tvb, *offset, 4, FALSE);
*offset += 4;
length -= 4;
proto_tree_add_item(entry_tree, hf_msdp_sa_src_addr, tvb, *offset, 4, FALSE);
*offset += 4;
length -= 4;
}
/*
* Check if an encapsulated multicast IPv4 packet follows
*/
if (tvb_reported_length_remaining(tvb, *offset) > 0) {
if (length > 0) {
proto_item *ei;
proto_tree *enc_tree;
gint available_length, reported_length;
tvbuff_t *next_tvb;
ei = proto_tree_add_text(tree, tvb, *offset, -1,
ei = proto_tree_add_text(tree, tvb, *offset, length,
"Encapsulated IPv4 packet: %u bytes",
tvb_reported_length_remaining(tvb, *offset));
length);
enc_tree = proto_item_add_subtree(ei, ett_msdp_sa_enc_data);
next_tvb = tvb_new_subset(tvb, *offset, -1, -1);
available_length = tvb_length_remaining(tvb, *offset);
reported_length = tvb_reported_length_remaining(tvb, *offset);
g_assert(available_length >= 0);
g_assert(reported_length >= 0);
if (available_length > reported_length)
available_length = reported_length;
if (available_length > length)
available_length = length;
if (reported_length > length)
reported_length = length;
next_tvb = tvb_new_subset(tvb, *offset, available_length,
reported_length);
/* Set the information columns read-only so that they
* reflect the MSDP packet rather than the
* encapsulated packet.
@ -296,7 +331,7 @@ static void dissect_msdp_sa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
col_set_writable(pinfo->cinfo, FALSE);
call_dissector(ip_handle, next_tvb, pinfo, enc_tree);
}
*offset += tvb_length_remaining(tvb, *offset);
*offset += length;
return;
}