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wireshark/epan/dissectors/packet-pw-satop.c
Michael Mann 1e60d63c8c Create call_data_dissector() to call data dissector. 
This saves many dissectors the need to find the data dissector and store a handle to it.

There were also some that were finding it, but not using it.
For others this was the only reason for their handoff function, so it could be eliminated.

Change-Id: I5d3f951ee1daa3d30c060d21bd12bbc881a8027b
Reviewed-on: https://code.wireshark.org/review/14530
Petri-Dish: Michael Mann <mmann78@netscape.net>
Reviewed-by: Michael Mann <mmann78@netscape.net>
2016-03-20 17:38:03 +00:00

491 lines
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/* packet-pw-satop.c
* Routines for SAToP PW dissection as per RFC4553.
* Copyright 2009, Dmitry Trebich, Artem Tamazov <artem.tamazov@tellabs.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.
*
* History:
* ---------------------------------
* 19.03.2009 initial implementation
* 14.08.2009 added: support for IP/UDP demultiplexing
* Not supported yet:
* - Decoding of PW payload
* - Optional RTP Headers (RFC3550)
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/expert.h>
#include "packet-mpls.h"
#include "packet-pw-common.h"
void proto_register_pw_satop(void);
void proto_reg_handoff_pw_satop(void);
static gint proto = -1;
static gint ett = -1;
static int hf_cw = -1;
static int hf_cw_bits03 = -1;
static int hf_cw_l = -1;
static int hf_cw_r = -1;
static int hf_cw_rsv = -1;
static int hf_cw_frg = -1;
static int hf_cw_len = -1;
static int hf_cw_seq = -1;
static int hf_payload = -1;
static int hf_payload_l = -1;
static expert_field ei_cw_rsv = EI_INIT;
static expert_field ei_payload_size_invalid_undecoded = EI_INIT;
static expert_field ei_payload_size_invalid = EI_INIT;
static expert_field ei_cw_frg = EI_INIT;
static expert_field ei_cw_bits03 = EI_INIT;
static expert_field ei_cw_packet_size_too_small = EI_INIT;
static dissector_handle_t pw_padding_handle;
const char pwc_longname_pw_satop[] = "SAToP (no RTP support)";
static const char shortname[] = "SAToP (no RTP)";
static
void dissect_pw_satop(tvbuff_t * tvb_original
,packet_info * pinfo
,proto_tree * tree
,pwc_demux_type_t demux)
{
const int encaps_size = 4; /*RTP header in encapsulation is not supported yet*/
gint packet_size;
gint payload_size;
gint padding_size;
int properties;
enum {
PAY_NO_IDEA = 0
,PAY_LIKE_E1
,PAY_LIKE_T1
,PAY_LIKE_E3_T3
,PAY_LIKE_OCTET_ALIGNED_T1
} payload_properties;
packet_size = tvb_reported_length_remaining(tvb_original, 0);
/*
* FIXME
* "4" below should be replaced by something like "min_packet_size_this_dissector"
* Also call to dissect_try_cw_first_nibble() should be moved before this block
*/
if (packet_size < 4) /* 4 is smallest size which may be sensible (for PWACH dissector) */
{
proto_item *item;
item = proto_tree_add_item(tree, proto, tvb_original, 0, -1, ENC_NA);
expert_add_info_format(pinfo, item, &ei_cw_packet_size_too_small,
"PW packet size (%d) is too small to carry sensible information"
,(int)packet_size);
col_set_str(pinfo->cinfo, COL_PROTOCOL, shortname);
col_set_str(pinfo->cinfo, COL_INFO, "Malformed: PW packet is too small");
return;
}
switch (demux)
{
case PWC_DEMUX_MPLS:
if (dissect_try_cw_first_nibble(tvb_original, pinfo, tree))
{
return;
}
break;
case PWC_DEMUX_UDP:
break;
default:
DISSECTOR_ASSERT_NOT_REACHED();
return;
}
/* check how "good" is this packet */
/* also decide payload length from packet size and CW */
properties = 0;
if (0 != (tvb_get_guint8(tvb_original, 0) & 0xf0 /*bits03*/))
{
properties |= PWC_CW_BAD_BITS03;
}
if (0 != (tvb_get_guint8(tvb_original, 0) & 0x03 /*rsv*/))
{
properties |= PWC_CW_BAD_RSV;
}
if (0 != (tvb_get_guint8(tvb_original, 1) & 0xc0 /*frag*/))
{
properties |= PWC_CW_BAD_FRAG;
}
{
/* RFC4553:
* [...MAY be used to carry the length of the SAToP
* packet (defined as the size of the SAToP header + the payload
* size) if it is less than 64 bytes, and MUST be set to zero
* otherwise... ]
*
* Note that this differs from RFC4385's definition of length:
* [ If the MPLS payload is less than 64 bytes, the length field
* MUST be set to the length of the PW payload...]
*
* We will use RFC4553's definition here.
*/
int cw_len;
gint payload_size_from_packet;
cw_len = tvb_get_guint8(tvb_original, 1) & 0x3f;
payload_size_from_packet = packet_size - encaps_size;
if (cw_len != 0)
{
gint payload_size_from_cw;
payload_size_from_cw = cw_len - encaps_size;
/*
* Assumptions for error case,
* will be overwritten if no errors found:
*/
payload_size = payload_size_from_packet;
padding_size = 0;
if (payload_size_from_cw < 0)
{
properties |= PWC_CW_BAD_PAYLEN_LT_0;
}
else if (payload_size_from_cw > payload_size_from_packet)
{
properties |= PWC_CW_BAD_PAYLEN_GT_PACKET;
}
else if (payload_size_from_packet >= 64)
{
properties |= PWC_CW_BAD_LEN_MUST_BE_0;
}
else /* ok */
{
payload_size = payload_size_from_cw;
padding_size = payload_size_from_packet - payload_size_from_cw; /* >=0 */
}
}
else
{
payload_size = payload_size_from_packet;
padding_size = 0;
}
}
if (payload_size == 0)
{
/*
* As CW.L it indicates that PW payload is invalid, dissector should
* not blame packets with bad payload (including "bad" or "strange" SIZE of
* payload) when L bit is set.
*/
if (0 == (tvb_get_guint8(tvb_original, 0) & 0x08 /*L bit*/))
{
properties |= PWC_PAY_SIZE_BAD;
}
}
/* guess about payload type */
if (payload_size == 256)
{
payload_properties = PAY_LIKE_E1;
}
else if (payload_size == 192)
{
payload_properties = PAY_LIKE_T1;
}
else if (payload_size == 1024)
{
payload_properties = PAY_LIKE_E3_T3;
}
else if ((payload_size != 0) && (payload_size % 25 == 0))
{
payload_properties = PAY_LIKE_OCTET_ALIGNED_T1;
}
else
{
payload_properties = PAY_NO_IDEA; /*we do not have any ideas about payload type*/
}
/* fill up columns*/
col_set_str(pinfo->cinfo, COL_PROTOCOL, shortname);
col_clear(pinfo->cinfo, COL_INFO);
if (properties & PWC_ANYOF_CW_BAD)
{
col_set_str(pinfo->cinfo, COL_INFO, "CW:Bad, ");
}
if (properties & PWC_PAY_SIZE_BAD)
{
col_append_str(pinfo->cinfo, COL_INFO, "Payload size:0 (Bad)");
}
else
{
col_append_fstr(pinfo->cinfo, COL_INFO, "TDM octets:%d", (int)payload_size);
}
if (padding_size != 0)
{
col_append_fstr(pinfo->cinfo, COL_INFO, ", Padding:%d", (int)padding_size);
}
{
proto_item* item;
item = proto_tree_add_item(tree, proto, tvb_original, 0, -1, ENC_NA);
pwc_item_append_cw(item,tvb_get_ntohl(tvb_original, 0),TRUE);
pwc_item_append_text_n_items(item,(int)payload_size,"octet");
{
proto_tree* tree2;
tree2 = proto_item_add_subtree(item, ett);
{
tvbuff_t* tvb;
proto_item* item2;
tvb = tvb_new_subset_length(tvb_original, 0, PWC_SIZEOF_CW);
item2 = proto_tree_add_item(tree2, hf_cw, tvb, 0, -1, ENC_NA);
pwc_item_append_cw(item2, tvb_get_ntohl(tvb, 0),FALSE);
{
proto_tree* tree3;
tree3 = proto_item_add_subtree(item2, ett);
{
proto_item* item3;
if (properties & PWC_CW_BAD_BITS03) /*display only if value is wrong*/
{
item3 = proto_tree_add_item(tree3, hf_cw_bits03, tvb, 0, 1, ENC_BIG_ENDIAN);
expert_add_info(pinfo, item3, &ei_cw_bits03);
}
proto_tree_add_item(tree3, hf_cw_l , tvb, 0, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(tree3, hf_cw_r , tvb, 0, 1, ENC_BIG_ENDIAN);
item3 = proto_tree_add_item(tree3, hf_cw_rsv, tvb, 0, 1, ENC_BIG_ENDIAN);
if (properties & PWC_CW_BAD_RSV)
{
expert_add_info(pinfo, item3, &ei_cw_rsv);
}
item3 = proto_tree_add_item(tree3, hf_cw_frg, tvb, 1, 1, ENC_BIG_ENDIAN);
if (properties & PWC_CW_BAD_FRAG)
{
expert_add_info(pinfo, item3, &ei_cw_frg);
}
item3 = proto_tree_add_item(tree3, hf_cw_len, tvb, 1, 1, ENC_BIG_ENDIAN);
if (properties & PWC_CW_BAD_PAYLEN_LT_0)
{
expert_add_info_format(pinfo, item3, &ei_payload_size_invalid,
"Bad Length: too small, must be > %d",
(int)encaps_size);
}
if (properties & PWC_CW_BAD_PAYLEN_GT_PACKET)
{
expert_add_info_format(pinfo, item3, &ei_payload_size_invalid,
"Bad Length: must be <= than PSN packet size (%d)",
(int)packet_size);
}
if (properties & PWC_CW_BAD_LEN_MUST_BE_0)
{
expert_add_info_format(pinfo, item3, &ei_payload_size_invalid,
"Bad Length: must be 0 if SAToP packet size (%d) is > 64",
(int)packet_size);
}
proto_tree_add_item(tree3, hf_cw_seq, tvb, 2, 2, ENC_BIG_ENDIAN);
}
}
}
}
/* payload */
if (properties & PWC_PAY_SIZE_BAD)
{
expert_add_info_format(pinfo, item, &ei_payload_size_invalid,
"SAToP payload: none found. Size of payload must be <> 0");
}
else if (payload_size == 0)
{
expert_add_info(pinfo, item, &ei_payload_size_invalid_undecoded);
}
else
{
proto_tree* tree2;
tree2 = proto_item_add_subtree(item, ett);
{
proto_item* item2;
tvbuff_t* tvb;
tvb = tvb_new_subset_length(tvb_original, PWC_SIZEOF_CW, payload_size);
item2 = proto_tree_add_item(tree2, hf_payload, tvb, 0, -1, ENC_NA);
pwc_item_append_text_n_items(item2,(int)payload_size,"octet");
{
proto_tree* tree3;
const char* s;
switch(payload_properties)
{
case PAY_LIKE_E1:
s = " (looks like E1)";
break;
case PAY_LIKE_T1:
s = " (looks like T1)";
break;
case PAY_LIKE_E3_T3:
s = " (looks like E3/T3)";
break;
case PAY_LIKE_OCTET_ALIGNED_T1:
s = " (looks like octet-aligned T1)";
break;
case PAY_NO_IDEA:
default:
s = "";
break;
}
proto_item_append_text(item2, "%s", s);
tree3 = proto_item_add_subtree(item2, ett);
call_data_dissector(tvb, pinfo, tree3);
item2 = proto_tree_add_int(tree3, hf_payload_l, tvb, 0, 0
,(int)payload_size); /* allow filtering */
PROTO_ITEM_SET_HIDDEN(item2);
}
}
}
/* padding */
if (padding_size > 0)
{
proto_tree* tree2;
tree2 = proto_item_add_subtree(item, ett);
{
tvbuff_t* tvb;
tvb = tvb_new_subset(tvb_original, PWC_SIZEOF_CW + payload_size, padding_size, -1);
call_dissector(pw_padding_handle, tvb, pinfo, tree2);
}
}
}
return;
}
static
int dissect_pw_satop_mpls( tvbuff_t * tvb_original, packet_info * pinfo, proto_tree * tree, void* data _U_)
{
dissect_pw_satop(tvb_original,pinfo,tree,PWC_DEMUX_MPLS);
return tvb_captured_length(tvb_original);
}
static
int dissect_pw_satop_udp( tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree, void* data _U_)
{
dissect_pw_satop(tvb,pinfo,tree,PWC_DEMUX_UDP);
return tvb_captured_length(tvb);
}
void proto_register_pw_satop(void)
{
static hf_register_info hf[] = {
{ &hf_cw ,{"Control Word" ,"pwsatop.cw"
,FT_NONE ,BASE_NONE ,NULL
,0 ,NULL ,HFILL }},
{&hf_cw_bits03,{"Bits 0 to 3" ,"pwsatop.cw.bits03"
,FT_UINT8 ,BASE_DEC ,NULL
,0xf0 ,NULL ,HFILL }},
{&hf_cw_l, {"L bit: TDM payload state" ,"pwsatop.cw.lbit"
,FT_UINT8 ,BASE_DEC ,VALS(pwc_vals_cw_l_bit)
,0x08 ,NULL ,HFILL }},
{&hf_cw_r, {"R bit: Local CE-bound IWF" ,"pwsatop.cw.rbit"
,FT_UINT8 ,BASE_DEC ,VALS(pwc_vals_cw_r_bit)
,0x04 ,NULL ,HFILL }},
{&hf_cw_rsv, {"Reserved" ,"pwsatop.cw.rsv"
,FT_UINT8 ,BASE_DEC ,NULL
,0x03 ,NULL ,HFILL }},
{&hf_cw_frg, {"Fragmentation" ,"pwsatop.cw.frag"
,FT_UINT8 ,BASE_DEC ,VALS(pwc_vals_cw_frag)
,0xc0 ,NULL ,HFILL }},
{&hf_cw_len, {"Length" ,"pwsatop.cw.length"
,FT_UINT8 ,BASE_DEC ,NULL
,0x3f ,NULL ,HFILL }},
{&hf_cw_seq, {"Sequence number" ,"pwsatop.cw.seqno"
,FT_UINT16 ,BASE_DEC ,NULL
,0 ,NULL ,HFILL }},
{&hf_payload ,{"TDM payload" ,"pwsatop.payload"
,FT_BYTES ,BASE_NONE ,NULL
,0 ,NULL ,HFILL }},
{&hf_payload_l ,{"TDM payload length" ,"pwsatop.payload.len"
,FT_INT32 ,BASE_DEC ,NULL
,0 ,NULL ,HFILL }}
};
static gint *ett_array[] = {
&ett
};
static ei_register_info ei[] = {
{ &ei_cw_packet_size_too_small, { "pwsatop.packet_size_too_small", PI_MALFORMED, PI_ERROR, "PW packet size (%d) is too small to carry sensible information", EXPFILL }},
{ &ei_cw_bits03, { "pwsatop.cw.bits03.not_zero", PI_MALFORMED, PI_ERROR, "Bits 0..3 of Control Word must be 0", EXPFILL }},
{ &ei_cw_rsv, { "pwsatop.cw.rsv.not_zero", PI_MALFORMED, PI_ERROR, "RSV bits of Control Word must be 0", EXPFILL }},
{ &ei_cw_frg, { "pwsatop.cw.frag.not_allowed", PI_MALFORMED, PI_ERROR, "Fragmentation of payload is not allowed for SAToP", EXPFILL }},
{ &ei_payload_size_invalid, { "pwsatop.payload.size_invalid", PI_MALFORMED, PI_ERROR, "Bad Length: too small", EXPFILL }},
{ &ei_payload_size_invalid_undecoded, { "pwsatop.payload.undecoded", PI_UNDECODED, PI_NOTE, "SAToP payload: omitted to conserve bandwidth", EXPFILL }},
};
expert_module_t* expert_pwsatop;
proto = proto_register_protocol(pwc_longname_pw_satop, shortname, "pwsatopcw");
proto_register_field_array(proto, hf, array_length(hf));
proto_register_subtree_array(ett_array, array_length(ett_array));
expert_pwsatop = expert_register_protocol(proto);
expert_register_field_array(expert_pwsatop, ei, array_length(ei));
register_dissector("pw_satop_udp", dissect_pw_satop_udp, proto);
return;
}
void proto_reg_handoff_pw_satop(void)
{
dissector_handle_t pw_satop_mpls_handle;
pw_padding_handle = find_dissector_add_dependency("pw_padding", proto);
/* For Decode As */
pw_satop_mpls_handle = create_dissector_handle( dissect_pw_satop_mpls, proto );
dissector_add_for_decode_as("mpls.label", pw_satop_mpls_handle);
dissector_add_for_decode_as("udp.port", find_dissector("pw_satop_udp"));
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
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