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Hoist the bulk of the stuff involved in calling a dissector through a 

handle into a routine "call_dissector_work()", and have
"dissector_try_port()" and "call_dissector()" use that routine (which
means that "call_dissector()" now saves and restores
"pinfo->can_desegment").

svn path=/trunk/; revision=6516
This commit is contained in:
Guy Harris 2002-10-28 23:04:15 +00:00
parent 522ef0a1b7
commit a7744b697f
1 changed files with 65 additions and 60 deletions
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125
epan/packet.c
View File

@ -1,7 +1,7 @@
/* packet.c
* Routines for packet disassembly
*
* $Id: packet.c,v 1.79 2002/10/22 08:22:05 guy Exp $
* $Id: packet.c,v 1.80 2002/10/28 23:04:15 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
@ -336,6 +336,57 @@ struct dissector_handle {
int proto_index;
};
/*
* Call a dissector through a handle.
* If the protocol for that handle isn't enabled, return 0 without
* calling the dissector.
* Otherwise, if the handle refers to a new-style dissector, call the
* dissector and return its return value, otherwise call it and return
* the length of the tvbuff pointed to by the argument.
*/
static int
call_dissector_work(dissector_handle_t handle, tvbuff_t *tvb,
packet_info *pinfo, proto_tree *tree)
{
const char *saved_proto;
guint16 saved_can_desegment;
int ret;
if (handle->proto_index != -1 &&
!proto_is_protocol_enabled(handle->proto_index)) {
/*
* The protocol isn't enabled.
*/
return 0;
}
saved_proto = pinfo->current_proto;
saved_can_desegment = pinfo->can_desegment;
/*
* can_desegment is set to 2 by anyone which offers the
* desegmentation api/service.
* Then everytime a subdissector is called it is decremented
* by one.
* Thus only the subdissector immediately on top of whoever
* offers this service can use it.
*/
pinfo->can_desegment = saved_can_desegment-(saved_can_desegment>0);
if (handle->proto_index != -1) {
pinfo->current_proto =
proto_get_protocol_short_name(handle->proto_index);
}
if (handle->is_new)
ret = (*handle->dissector.new)(tvb, pinfo, tree);
else {
(*handle->dissector.old)(tvb, pinfo, tree);
ret = tvb_length(tvb);
}
pinfo->current_proto = saved_proto;
pinfo->can_desegment = saved_can_desegment;
return ret;
}
/*
* An entry in the hash table portion of a dissector table.
*/
@ -518,9 +569,7 @@ dissector_try_port(dissector_table_t sub_dissectors, guint32 port,
{
dtbl_entry_t *dtbl_entry;
struct dissector_handle *handle;
const char *saved_proto;
guint32 saved_match_port;
guint16 saved_can_desegment;
int ret;
dtbl_entry = g_hash_table_lookup(sub_dissectors->hash_table,
@ -540,48 +589,14 @@ dissector_try_port(dissector_table_t sub_dissectors, guint32 port,
}
/*
* Yes - is its protocol enabled?
* Save the current value of "pinfo->match_port",
* set it to the port that matched, call the
* dissector, and restore "pinfo->match_port".
*/
if (handle->proto_index != -1 &&
!proto_is_protocol_enabled(handle->proto_index)) {
/*
* No - pretend this dissector didn't exist,
* so that other dissectors might have a chance
* to dissect this packet.
*/
return FALSE;
}
/*
* Yes, it's enabled.
*/
saved_proto = pinfo->current_proto;
saved_match_port = pinfo->match_port;
saved_can_desegment = pinfo->can_desegment;
/*
* can_desegment is set to 2 by anyone which offers the
* desegmentation api/service.
* Then everytime a subdissector is called it is decremented
* by one.
* Thus only the subdissector immediately on top of whoever
* offers this serveice can use it.
*/
pinfo->can_desegment = saved_can_desegment-(saved_can_desegment>0);
pinfo->match_port = port;
if (handle->proto_index != -1) {
pinfo->current_proto =
proto_get_protocol_short_name(handle->proto_index);
}
if (handle->is_new)
ret = (*handle->dissector.new)(tvb, pinfo, tree);
else {
(*handle->dissector.old)(tvb, pinfo, tree);
ret = 1;
}
pinfo->current_proto = saved_proto;
ret = call_dissector_work(handle, tvb, pinfo, tree);
pinfo->match_port = saved_match_port;
pinfo->can_desegment = saved_can_desegment;
/*
* If a new-style dissector returned 0, it means that
@ -590,8 +605,11 @@ dissector_try_port(dissector_table_t sub_dissectors, guint32 port,
*
* Old-style dissectors can't reject the packet.
*
* If the packet was rejected, we return FALSE, otherwise
* we return TRUE.
* 0 is also returned if the protocol wasn't enabled.
*
* If the packet was rejected, we return FALSE, so that
* other dissectors might have a chance to dissect this
* packet, otherwise we return TRUE.
*/
return ret != 0;
}
@ -1074,31 +1092,18 @@ int
call_dissector(dissector_handle_t handle, tvbuff_t *tvb,
packet_info *pinfo, proto_tree *tree)
{
const char *saved_proto;
int ret;
if (handle->proto_index != -1 &&
!proto_is_protocol_enabled(handle->proto_index)) {
ret = call_dissector_work(handle, tvb, pinfo, tree);
if (ret == 0) {
/*
* No - just dissect this packet as data.
* The protocol was disabled, or the dissector rejected
* it. Just dissect this packet as data.
*/
g_assert(data_handle != NULL);
g_assert(data_handle->proto_index != -1);
call_dissector(data_handle, tvb, pinfo, tree);
return tvb_length(tvb);
}
saved_proto = pinfo->current_proto;
if (handle->proto_index != -1) {
pinfo->current_proto =
proto_get_protocol_short_name(handle->proto_index);
}
if (handle->is_new)
ret = (*handle->dissector.new)(tvb, pinfo, tree);
else {
(*handle->dissector.old)(tvb, pinfo, tree);
ret = tvb_length(tvb);
}
pinfo->current_proto = saved_proto;
return ret;
}