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wireshark/epan/dissectors/packet-openflow.c
Michael Mann 268841f3e0 Combine Decode As and port preferences for tcp.port dissector table. 
This patch introduces new APIs to allow dissectors to have a preference for
a (TCP) port, but the underlying data is actually part of Decode As functionality.
For now the APIs are intentionally separate from the regular APIs that register a
dissector within a dissector table.  It may be possible to eventually combine the
two so that all dissectors that register with a dissector table have an opportunity
to "automatically" have a preference to adjust the "table value" through the
preferences dialog.

The tcp.port dissector table was used as the guinea pig.  This will eventually be
expanded to other dissector tables as well (most notably UDP ports).  Some
dissectors that "shared" a TCP/UDP port preference were also converted. It also
removed the need for some preference callback functions (mostly when the callback
function was the proto_reg_handoff function) so there is cleanup around that.

Dissectors that has a port preference whose default was 0 were switched to using
the dissector_add_for_decode_as_with_preference API rather than dissector_add_uint_with_preference

Also added comments for TCP ports used that aren't IANA registered.

Change-Id: I99604f95d426ad345f4b494598d94178b886eb67
Reviewed-on: https://code.wireshark.org/review/17724
Reviewed-by: Michael Mann <mmann78@netscape.net>
2016-10-08 02:44:53 +00:00

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/* packet-openflow.c
* Routines for OpenFlow dissection
* Copyright 2013, Anders Broman <anders.broman@ericsson.com>
* Copyright 2013, Zoltan Lajos Kis <zoltan.lajos.kis@ericsson.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Ref https://www.opennetworking.org/sdn-resources/onf-specifications/openflow
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/expert.h>
#include <epan/prefs.h>
#include <epan/prefs-int.h>
#include "packet-tcp.h"
void proto_register_openflow(void);
void proto_reg_handoff_openflow(void);
#define OFP_LEGACY_PORT 6633
#define OFP_LEGACY2_PORT 6634
#define OFP_IANA_PORT 6653
static int g_openflow_port = OFP_IANA_PORT;
static dissector_handle_t openflow_handle;
static dissector_handle_t openflow_v1_handle;
static dissector_handle_t openflow_v4_handle;
static dissector_handle_t openflow_v5_handle;
/* Initialize the protocol and registered fields */
static int proto_openflow = -1;
static int hf_openflow_version = -1;
static expert_field ei_openflow_version = EI_INIT;
static gboolean openflow_desegment = TRUE;
#define OFP_VERSION_1_0 1
#define OFP_VERSION_1_1 2
#define OFP_VERSION_1_2 3
#define OFP_VERSION_1_3 4
#define OFP_VERSION_1_4 5
static const value_string openflow_version_values[] = {
{ 0x01, "1.0" },
{ 0x02, "1.1" },
{ 0x03, "1.2" },
{ 0x04, "1.3" },
{ 0x05, "1.4" },
{ 0, NULL }
};
static guint
get_openflow_pdu_length(packet_info *pinfo _U_, tvbuff_t *tvb,
int offset, void *data _U_)
{
return tvb_get_ntohs(tvb, offset + 2);
}
static int
dissect_openflow_tcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
guint offset = 0;
guint8 version;
proto_item* ti;
version = tvb_get_guint8(tvb, 0);
/* Set the Protocol column to the constant string of openflow */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "OpenFlow");
col_clear(pinfo->cinfo,COL_INFO);
switch(version){
case OFP_VERSION_1_0:
call_dissector(openflow_v1_handle, tvb, pinfo, tree);
break;
case OFP_VERSION_1_3:
call_dissector(openflow_v4_handle, tvb, pinfo, tree);
break;
case OFP_VERSION_1_4:
call_dissector(openflow_v5_handle, tvb, pinfo, tree);
break;
default:
ti = proto_tree_add_item(tree, hf_openflow_version, tvb, offset, 1, ENC_BIG_ENDIAN);
expert_add_info(pinfo, ti, &ei_openflow_version);
break;
}
return tvb_reported_length(tvb);
}
#define OFP_HEADER_LEN 8
static int
dissect_openflow(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
tcp_dissect_pdus(tvb, pinfo, tree, openflow_desegment, OFP_HEADER_LEN,
get_openflow_pdu_length, dissect_openflow_tcp_pdu, data);
return tvb_captured_length(tvb);
}
static gboolean
dissect_openflow_heur(tvbuff_t *tvb, packet_info *pinfo,
proto_tree *tree, void *data)
{
conversation_t *conversation = NULL;
if ((pinfo->destport != OFP_LEGACY_PORT) &&
(pinfo->destport != OFP_LEGACY2_PORT) &&
(pinfo->destport != OFP_IANA_PORT) &&
(pinfo->destport != (guint32)g_openflow_port)) {
return FALSE;
}
conversation = find_or_create_conversation(pinfo);
conversation_set_dissector(conversation, openflow_handle);
dissect_openflow(tvb, pinfo, tree, data);
return TRUE;
}
static void
apply_openflow_prefs(void)
{
/* Openflow uses the port preference for heuristics */
pref_t *openflow_port = prefs_find_preference(prefs_find_module("openflow"), "tcp.port");
g_openflow_port = *openflow_port->varp.uint;
}
/*
* Register the protocol with Wireshark.
*/
void
proto_register_openflow(void)
{
static hf_register_info hf[] = {
{ &hf_openflow_version,
{ "Version", "openflow.version",
FT_UINT8, BASE_HEX, VALS(openflow_version_values), 0x7f,
NULL, HFILL }
}
};
static ei_register_info ei[] = {
{ &ei_openflow_version, { "openflow.version.unknown", PI_UNDECODED, PI_WARN, "Unsupported version not dissected", EXPFILL }},
};
module_t *openflow_module;
expert_module_t* expert_openflow;
/* Register the protocol name and description */
proto_openflow = proto_register_protocol("OpenFlow",
"OpenFlow", "openflow");
openflow_handle = register_dissector("openflow", dissect_openflow, proto_openflow);
/* Required function calls to register the header fields and subtrees */
proto_register_field_array(proto_openflow, hf, array_length(hf));
expert_openflow = expert_register_protocol(proto_openflow);
expert_register_field_array(expert_openflow, ei, array_length(ei));
openflow_module = prefs_register_protocol(proto_openflow, apply_openflow_prefs);
/* Register heuristic preference */
prefs_register_obsolete_preference(openflow_module, "heuristic");
/* Register desegment preference */
prefs_register_bool_preference(openflow_module, "desegment",
"Reassemble OpenFlow messages spanning multiple TCP segments",
"Whether the OpenFlow dissector should reassemble messages spanning multiple TCP segments."
" To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
&openflow_desegment);
}
void
proto_reg_handoff_openflow(void)
{
heur_dissector_add("tcp", dissect_openflow_heur, "OpenFlow over TCP", "openflow_tcp", proto_openflow, HEURISTIC_ENABLE);
dissector_add_uint_with_preference("tcp.port", OFP_IANA_PORT, openflow_handle);
openflow_v1_handle = find_dissector_add_dependency("openflow_v1", proto_openflow);
openflow_v4_handle = find_dissector_add_dependency("openflow_v4", proto_openflow);
openflow_v5_handle = find_dissector_add_dependency("openflow_v5", proto_openflow);
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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