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An SPX packet is not a retransmission of an earlier packet unless the 

two packets have the same sequence number; use the sequence number in
the hash key.

The sequence number is not incremented for system packets, and system
packets probably don't get ACKed and thus presumably don't get
retransmitted, so don't do retransmission checks for system packets.

svn path=/trunk/; revision=7442
This commit is contained in:
Guy Harris 2003-04-12 07:35:52 +00:00
parent e0d9bb60a2
commit 4f697a69f3
1 changed files with 96 additions and 63 deletions
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159
packet-ipx.c
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@ -6,7 +6,7 @@
* Portions Copyright (c) 2000-2002 by Gilbert Ramirez.
* Portions Copyright (c) Novell, Inc. 2002-2003
*
* $Id: packet-ipx.c,v 1.127 2003/04/12 05:36:10 guy Exp $
* $Id: packet-ipx.c,v 1.128 2003/04/12 07:35:52 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
@ -357,11 +357,11 @@ dissect_ipx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
typedef struct {
conversation_t *conversation;
guint32 spx_src;
guint32 spx_src;
guint16 spx_seq;
} spx_hash_key;
typedef struct {
guint16 spx_seq;
guint16 spx_ack;
guint16 spx_all;
guint32 num;
@ -388,7 +388,8 @@ spx_equal(gconstpointer v, gconstpointer v2)
const spx_hash_key *val2 = (const spx_hash_key*)v2;
if (val1->conversation == val2->conversation &&
val1->spx_src == val2->spx_src ) {
val1->spx_src == val2->spx_src &&
val1->spx_seq == val2->spx_seq) {
return 1;
}
return 0;
@ -456,7 +457,7 @@ spx_postseq_cleanup(void)
}
spx_hash_value*
spx_hash_insert(conversation_t *conversation, guint32 spx_src)
spx_hash_insert(conversation_t *conversation, guint32 spx_src, guint16 spx_seq)
{
spx_hash_key *key;
spx_hash_value *value;
@ -465,9 +466,9 @@ spx_hash_insert(conversation_t *conversation, guint32 spx_src)
key = g_mem_chunk_alloc(spx_hash_keys);
key->conversation = conversation;
key->spx_src = spx_src;
key->spx_seq = spx_seq;
value = g_mem_chunk_alloc(spx_hash_values);
value->spx_seq = 0;
value->spx_ack = 0;
value->spx_all = 0;
value->num = 0;
@ -479,12 +480,13 @@ spx_hash_insert(conversation_t *conversation, guint32 spx_src)
/* Returns the spx_hash_value*, or NULL if not found. */
spx_hash_value*
spx_hash_lookup(conversation_t *conversation, guint32 spx_src)
spx_hash_lookup(conversation_t *conversation, guint32 spx_src, guint32 spx_seq)
{
spx_hash_key key;
key.conversation = conversation;
key.spx_src = spx_src;
key.spx_seq = spx_seq;
return g_hash_table_lookup(spx_hash, &key);
}
@ -547,6 +549,7 @@ dissect_spx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
guint8 conn_ctrl;
proto_tree *cc_tree;
guint8 datastream_type;
guint16 spx_seq;
const char *spx_msg_string;
guint16 low_socket, high_socket;
guint32 src;
@ -594,7 +597,10 @@ dissect_spx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
proto_tree_add_item(spx_tree, hf_spx_src_id, tvb, 2, 2, FALSE);
proto_tree_add_item(spx_tree, hf_spx_dst_id, tvb, 4, 2, FALSE);
proto_tree_add_item(spx_tree, hf_spx_seq_nr, tvb, 6, 2, FALSE);
}
spx_seq = tvb_get_ntohs(tvb, 6);
if (tree) {
proto_tree_add_uint(spx_tree, hf_spx_seq_nr, tvb, 6, 2, spx_seq);
proto_tree_add_item(spx_tree, hf_spx_ack_nr, tvb, 8, 2, FALSE);
proto_tree_add_item(spx_tree, hf_spx_all_nr, tvb, 10, 2, FALSE);
}
@ -614,67 +620,94 @@ dissect_spx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
* we should probably use the direction, as well as the conversation,
* as part of the hash key; if we do that, we can probably just
* use PT_IPX as the port type, and possibly get rid of PT_NCP.
*
* According to
*
* http://developer.novell.com/research/appnotes/1995/december/03/apv.htm
*
* the sequence number is not incremented for system packets, so
* presumably that means there is no notion of a system packet
* being retransmitted; that document also says that system
* packets are used as "I'm still here" keepalives and as
* acknowledgements (presumably meaning ACK-only packets), which
* suggests that they might not be ACKed and thus might not
* be retransmitted.
*/
if (!pinfo->fd->flags.visited) {
conversation = find_conversation(&pinfo->src, &pinfo->dst,
PT_NCP, pinfo->srcport, pinfo->srcport, 0);
if (conversation == NULL) {
/*
* It's not part of any conversation - create a new
* one.
*/
conversation = conversation_new(&pinfo->src,
&pinfo->dst, PT_NCP, pinfo->srcport,
pinfo->srcport, 0);
}
if (conn_ctrl & SPX_SYS_PACKET) {
/*
* Now we'll hash the SPX header and use the result of that,
* plus the conversation, as a hash key to identify this
* packet.
*
* If we don't find it in the hash table, it's not a
* retransmission, otherwise it is. If we don't find it,
* we enter it into the hash table, with the frame number.
* If we do, we attach to this frame a structure giving
* the frame number of the original transmission, so that
* we, and subdissectors, know it's a retransmission.
* It's a system packet, so it isn't a retransmission.
*/
src = tvb_get_ntohs(tvb, 0)+tvb_get_ntohs(tvb, 2)+tvb_get_ntohs(tvb, 4)+tvb_get_ntohs(tvb, 6)+tvb_get_ntohs(tvb, 8);
pkt_value = spx_hash_lookup(conversation, src);
if (pkt_value == NULL) {
/*
* Not found in the hash table.
* Enter it into the hash table.
*/
pkt_value = spx_hash_insert(conversation, src);
pkt_value->spx_seq = tvb_get_ntohs(tvb, 6);
pkt_value->spx_ack = tvb_get_ntohs(tvb, 8);
pkt_value->spx_all = tvb_get_ntohs(tvb, 10);
pkt_value->num = pinfo->fd->num;
/*
* This is not a retransmission, so we shouldn't
* have any retransmission indicator.
*/
spx_rexmit_info = NULL;
} else {
/*
* Found in the hash table. Mark this frame as
* a retransmission.
*/
spx_rexmit_info = g_mem_chunk_alloc(spx_rexmit_infos);
spx_rexmit_info->num = pkt_value->num;
p_add_proto_data(pinfo->fd, proto_spx, spx_rexmit_info);
}
spx_rexmit_info = NULL;
} else {
/*
* Do we have per-packet SPX data for this frame?
* If so, it's a retransmission, and the per-packet
* data indicates which frame had the original
* transmission.
* Not a system packet - check for retransmissions.
*/
spx_rexmit_info = p_get_proto_data(pinfo->fd, proto_spx);
if (!pinfo->fd->flags.visited) {
conversation = find_conversation(&pinfo->src,
&pinfo->dst, PT_NCP, pinfo->srcport,
pinfo->srcport, 0);
if (conversation == NULL) {
/*
* It's not part of any conversation - create
* a new one.
*/
conversation = conversation_new(&pinfo->src,
&pinfo->dst, PT_NCP, pinfo->srcport,
pinfo->srcport, 0);
}
/*
* Now we'll hash the SPX header and use the result
* of that, plus the conversation, as a hash key to
* identify this packet.
*
* If we don't find it in the hash table, it's not a
* retransmission, otherwise it is. If we don't find
* it, we enter it into the hash table, with the
* frame number.
* If we do, we attach to this frame a structure giving
* the frame number of the original transmission, so
* that we, and subdissectors, know it's a
* retransmission.
*/
src = tvb_get_ntohs(tvb, 0)+tvb_get_ntohs(tvb, 2)+tvb_get_ntohs(tvb, 4)+tvb_get_ntohs(tvb, 6)+tvb_get_ntohs(tvb, 8);
pkt_value = spx_hash_lookup(conversation, src, spx_seq);
if (pkt_value == NULL) {
/*
* Not found in the hash table.
* Enter it into the hash table.
*/
pkt_value = spx_hash_insert(conversation, src,
spx_seq);
pkt_value->spx_ack = tvb_get_ntohs(tvb, 8);
pkt_value->spx_all = tvb_get_ntohs(tvb, 10);
pkt_value->num = pinfo->fd->num;
/*
* This is not a retransmission, so we shouldn't
* have any retransmission indicator.
*/
spx_rexmit_info = NULL;
} else {
/*
* Found in the hash table. Mark this frame as
* a retransmission.
*/
spx_rexmit_info = g_mem_chunk_alloc(spx_rexmit_infos);
spx_rexmit_info->num = pkt_value->num;
p_add_proto_data(pinfo->fd, proto_spx,
spx_rexmit_info);
}
} else {
/*
* Do we have per-packet SPX data for this frame?
* If so, it's a retransmission, and the per-packet
* data indicates which frame had the original
* transmission.
*/
spx_rexmit_info = p_get_proto_data(pinfo->fd,
proto_spx);
}
}
/*