![Bill Meier](/assets/img/avatar_default.png)
packet-mpls.c: - refactor dissect_pw_ach(); - create/uer value_string_ext as appropriate; - use call_dissector() rather than direct dissector call in one cse; all: - use 'LABEL' prefix for a set of rather generic enum identifiers; - fix some cases of calling expert...() or sub-dissectors under 'if(tree)'; - reformat some hf[] entries; - do some whitespace changes. svn path=/trunk/; revision=45195
456 lines
13 KiB
C
456 lines
13 KiB
C
/* packet-pw-satop.c
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* Routines for SAToP PW dissection as per RFC4553.
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* Copyright 2009, Dmitry Trebich, Artem Tamazov <artem.tamazov@tellabs.com>
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* History:
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* ---------------------------------
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* 19.03.2009 initial implementation
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* 14.08.2009 added: support for IP/UDP demultiplexing
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* Not supported yet:
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* - Decoding of PW payload
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* - Optional RTP Headers (RFC3550)
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*/
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#include "config.h"
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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/expert.h>
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#include "packet-mpls.h"
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#include "packet-pw-common.h"
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static gint proto = -1;
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static gint ett = -1;
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static int hf_cw = -1;
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static int hf_cw_bits03 = -1;
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static int hf_cw_l = -1;
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static int hf_cw_r = -1;
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static int hf_cw_rsv = -1;
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static int hf_cw_frg = -1;
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static int hf_cw_len = -1;
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static int hf_cw_seq = -1;
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static int hf_payload = -1;
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static int hf_payload_l = -1;
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static dissector_handle_t data_handle;
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static dissector_handle_t pw_padding_handle;
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const char pwc_longname_pw_satop[] = "SAToP (no RTP support)";
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static const char shortname[] = "SAToP (no RTP)";
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static
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void dissect_pw_satop(tvbuff_t * tvb_original
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,packet_info * pinfo
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,proto_tree * tree
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,pwc_demux_type_t demux)
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{
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const int encaps_size = 4; /*RTP header in encapsulation is not supported yet*/
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gint packet_size;
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gint payload_size;
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gint padding_size;
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pwc_packet_properties_t properties;
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enum {
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PAY_NO_IDEA = 0
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,PAY_LIKE_E1
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,PAY_LIKE_T1
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,PAY_LIKE_E3_T3
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,PAY_LIKE_OCTET_ALIGNED_T1
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} payload_properties;
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packet_size = tvb_reported_length_remaining(tvb_original, 0);
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/*
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* FIXME
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* "4" below should be replaced by something like "min_packet_size_this_dissector"
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* Also call to dissect_try_cw_first_nibble() should be moved before this block
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*/
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if (packet_size < 4) /* 4 is smallest size which may be sensible (for PWACH dissector) */
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{
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proto_item *item;
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item = proto_tree_add_item(tree, proto, tvb_original, 0, -1, ENC_NA);
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expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
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"PW packet size (%d) is too small to carry sensible information"
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,(int)packet_size);
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col_set_str(pinfo->cinfo, COL_PROTOCOL, shortname);
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col_set_str(pinfo->cinfo, COL_INFO, "Malformed: PW packet is too small");
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return;
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}
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switch (demux)
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{
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case PWC_DEMUX_MPLS:
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if (dissect_try_cw_first_nibble(tvb_original, pinfo, tree))
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{
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return;
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}
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break;
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case PWC_DEMUX_UDP:
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break;
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default:
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DISSECTOR_ASSERT_NOT_REACHED();
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return;
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}
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/* check how "good" is this packet */
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/* also decide payload length from packet size and CW */
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properties = 0;
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if (0 != (tvb_get_guint8(tvb_original, 0) & 0xf0 /*bits03*/))
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{
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properties |= PWC_CW_BAD_BITS03;
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}
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if (0 != (tvb_get_guint8(tvb_original, 0) & 0x03 /*rsv*/))
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{
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properties |= PWC_CW_BAD_RSV;
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}
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if (0 != (tvb_get_guint8(tvb_original, 1) & 0xc0 /*frag*/))
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{
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properties |= PWC_CW_BAD_FRAG;
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}
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{
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/* RFC4553:
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* [...MAY be used to carry the length of the SAToP
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* packet (defined as the size of the SAToP header + the payload
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* size) if it is less than 64 bytes, and MUST be set to zero
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* otherwise... ]
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*
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* Note that this differs from RFC4385's definition of length:
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* [ If the MPLS payload is less than 64 bytes, the length field
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* MUST be set to the length of the PW payload...]
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*
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* We will use RFC4553's definition here.
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*/
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int cw_len;
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gint payload_size_from_packet;
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cw_len = tvb_get_guint8(tvb_original, 1) & 0x3f;
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payload_size_from_packet = packet_size - encaps_size;
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if (cw_len != 0)
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{
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gint payload_size_from_cw;
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payload_size_from_cw = cw_len - encaps_size;
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/*
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* Assumptions for error case,
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* will be overwritten if no errors found:
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*/
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payload_size = payload_size_from_packet;
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padding_size = 0;
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if (payload_size_from_cw < 0)
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{
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properties |= PWC_CW_BAD_PAYLEN_LT_0;
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}
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else if (payload_size_from_cw > payload_size_from_packet)
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{
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properties |= PWC_CW_BAD_PAYLEN_GT_PACKET;
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}
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else if (payload_size_from_packet >= 64)
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{
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properties |= PWC_CW_BAD_LEN_MUST_BE_0;
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}
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else /* ok */
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{
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payload_size = payload_size_from_cw;
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padding_size = payload_size_from_packet - payload_size_from_cw; /* >=0 */
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}
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}
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else
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{
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payload_size = payload_size_from_packet;
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padding_size = 0;
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}
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}
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if (payload_size == 0)
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{
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/*
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* As CW.L it indicates that PW payload is invalid, dissector should
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* not blame packets with bad payload (including "bad" or "strange" SIZE of
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* payload) when L bit is set.
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*/
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if (0 == (tvb_get_guint8(tvb_original, 0) & 0x08 /*L bit*/))
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{
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properties |= PWC_PAY_SIZE_BAD;
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}
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}
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/* guess about payload type */
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if (payload_size == 256)
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{
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payload_properties = PAY_LIKE_E1;
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}
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else if (payload_size == 192)
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{
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payload_properties = PAY_LIKE_T1;
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}
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else if (payload_size == 1024)
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{
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payload_properties = PAY_LIKE_E3_T3;
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}
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else if ((payload_size != 0) && (payload_size % 25 == 0))
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{
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payload_properties = PAY_LIKE_OCTET_ALIGNED_T1;
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}
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else
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{
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payload_properties = PAY_NO_IDEA; /*we do not have any ideas about payload type*/
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}
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/* fill up columns*/
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col_set_str(pinfo->cinfo, COL_PROTOCOL, shortname);
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if (check_col(pinfo->cinfo, COL_INFO))
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{
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col_clear(pinfo->cinfo, COL_INFO);
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if (properties & PWC_ANYOF_CW_BAD)
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{
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col_append_str(pinfo->cinfo, COL_INFO, "CW:Bad, ");
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}
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if (properties & PWC_PAY_SIZE_BAD)
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{
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col_append_str(pinfo->cinfo, COL_INFO, "Payload size:0 (Bad)");
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}
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else
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{
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col_append_fstr(pinfo->cinfo, COL_INFO, "TDM octets:%d", (int)payload_size);
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}
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if (padding_size != 0)
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{
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col_append_fstr(pinfo->cinfo, COL_INFO, ", Padding:%d", (int)padding_size);
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}
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}
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{
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proto_item* item;
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item = proto_tree_add_item(tree, proto, tvb_original, 0, -1, ENC_NA);
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pwc_item_append_cw(item,tvb_get_ntohl(tvb_original, 0),TRUE);
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pwc_item_append_text_n_items(item,(int)payload_size,"octet");
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{
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proto_tree* tree2;
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tree2 = proto_item_add_subtree(item, ett);
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{
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tvbuff_t* tvb;
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proto_item* item2;
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tvb = tvb_new_subset(tvb_original, 0, PWC_SIZEOF_CW, PWC_SIZEOF_CW);
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item2 = proto_tree_add_item(tree2, hf_cw, tvb, 0, -1, ENC_NA);
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pwc_item_append_cw(item2, tvb_get_ntohl(tvb, 0),FALSE);
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{
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proto_tree* tree3;
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tree3 = proto_item_add_subtree(item2, ett);
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{
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proto_item* item3;
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if (properties & PWC_CW_BAD_BITS03) /*display only if value is wrong*/
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{
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item3 = proto_tree_add_item(tree3, hf_cw_bits03, tvb, 0, 1, ENC_BIG_ENDIAN);
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expert_add_info_format(pinfo, item3, PI_MALFORMED, PI_ERROR
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,"Bits 0..3 of Control Word must be 0");
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}
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proto_tree_add_item(tree3, hf_cw_l , tvb, 0, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(tree3, hf_cw_r , tvb, 0, 1, ENC_BIG_ENDIAN);
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item3 = proto_tree_add_item(tree3, hf_cw_rsv, tvb, 0, 1, ENC_BIG_ENDIAN);
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if (properties & PWC_CW_BAD_RSV)
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{
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expert_add_info_format(pinfo, item3, PI_MALFORMED, PI_ERROR
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,"RSV bits of Control Word must be 0");
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}
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item3 = proto_tree_add_item(tree3, hf_cw_frg, tvb, 1, 1, ENC_BIG_ENDIAN);
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if (properties & PWC_CW_BAD_FRAG)
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{
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expert_add_info_format(pinfo, item3, PI_MALFORMED, PI_ERROR
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,"Fragmentation of payload is not allowed for SAToP");
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}
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item3 = proto_tree_add_item(tree3, hf_cw_len, tvb, 1, 1, ENC_BIG_ENDIAN);
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if (properties & PWC_CW_BAD_PAYLEN_LT_0)
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{
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expert_add_info_format(pinfo, item3, PI_MALFORMED, PI_ERROR
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,"Bad Length: too small, must be > %d"
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,(int)encaps_size);
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}
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if (properties & PWC_CW_BAD_PAYLEN_GT_PACKET)
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{
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expert_add_info_format(pinfo, item3, PI_MALFORMED, PI_ERROR
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,"Bad Length: must be <= than PSN packet size (%d)"
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,(int)packet_size);
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}
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if (properties & PWC_CW_BAD_LEN_MUST_BE_0)
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{
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expert_add_info_format(pinfo, item3, PI_MALFORMED, PI_ERROR
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,"Bad Length: must be 0 if SAToP packet size (%d) is > 64"
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,(int)packet_size);
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}
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proto_tree_add_item(tree3, hf_cw_seq, tvb, 2, 2, ENC_BIG_ENDIAN);
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}
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}
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}
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}
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/* payload */
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if (properties & PWC_PAY_SIZE_BAD)
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{
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expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
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"SAToP payload: none found. Size of payload must be <> 0");
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}
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else if (payload_size == 0)
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{
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expert_add_info_format(pinfo, item, PI_UNDECODED, PI_NOTE,
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"SAToP payload: omitted to conserve bandwidth");
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}
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else
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{
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proto_tree* tree2;
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tree2 = proto_item_add_subtree(item, ett);
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{
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proto_item* item2;
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tvbuff_t* tvb;
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tvb = tvb_new_subset(tvb_original, PWC_SIZEOF_CW, payload_size, payload_size);
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item2 = proto_tree_add_item(tree2, hf_payload, tvb, 0, -1, ENC_NA);
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pwc_item_append_text_n_items(item2,(int)payload_size,"octet");
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{
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proto_tree* tree3;
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const char* s;
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switch(payload_properties)
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{
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case PAY_LIKE_E1:
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s = " (looks like E1)";
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break;
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case PAY_LIKE_T1:
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s = " (looks like T1)";
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break;
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case PAY_LIKE_E3_T3:
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s = " (looks like E3/T3)";
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break;
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case PAY_LIKE_OCTET_ALIGNED_T1:
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s = " (looks like octet-aligned T1)";
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break;
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case PAY_NO_IDEA:
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default:
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s = "";
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break;
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}
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proto_item_append_text(item2, "%s", s);
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tree3 = proto_item_add_subtree(item2, ett);
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call_dissector(data_handle, tvb, pinfo, tree3);
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item2 = proto_tree_add_int(tree3, hf_payload_l, tvb, 0, 0
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,(int)payload_size); /* allow filtering */
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PROTO_ITEM_SET_HIDDEN(item2);
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}
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}
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}
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/* padding */
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if (padding_size > 0)
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{
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proto_tree* tree2;
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tree2 = proto_item_add_subtree(item, ett);
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{
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tvbuff_t* tvb;
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tvb = tvb_new_subset(tvb_original, PWC_SIZEOF_CW + payload_size, padding_size, -1);
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call_dissector(pw_padding_handle, tvb, pinfo, tree2);
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}
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}
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}
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return;
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}
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static
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void dissect_pw_satop_mpls( tvbuff_t * tvb_original, packet_info * pinfo, proto_tree * tree)
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{
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dissect_pw_satop(tvb_original,pinfo,tree,PWC_DEMUX_MPLS);
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return;
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}
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static
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void dissect_pw_satop_udp( tvbuff_t * tvb_original, packet_info * pinfo, proto_tree * tree)
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{
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dissect_pw_satop(tvb_original,pinfo,tree,PWC_DEMUX_UDP);
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return;
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}
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void proto_register_pw_satop(void)
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{
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static hf_register_info hf[] = {
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{ &hf_cw ,{"Control Word" ,"pwsatop.cw"
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,FT_NONE ,BASE_NONE ,NULL
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,0 ,NULL ,HFILL }}
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,{&hf_cw_bits03,{"Bits 0 to 3" ,"pwsatop.cw.bits03"
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,FT_UINT8 ,BASE_DEC ,NULL
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,0xf0 ,NULL ,HFILL }}
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,{&hf_cw_l, {"L bit: TDM payload state" ,"pwsatop.cw.lbit"
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,FT_UINT8 ,BASE_DEC ,VALS(pwc_vals_cw_l_bit)
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,0x08 ,NULL ,HFILL }}
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,{&hf_cw_r, {"R bit: Local CE-bound IWF" ,"pwsatop.cw.rbit"
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,FT_UINT8 ,BASE_DEC ,VALS(pwc_vals_cw_r_bit)
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,0x04 ,NULL ,HFILL }}
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,{&hf_cw_rsv, {"Reserved" ,"pwsatop.cw.rsv"
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,FT_UINT8 ,BASE_DEC ,NULL
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,0x03 ,NULL ,HFILL }}
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,{&hf_cw_frg, {"Fragmentation" ,"pwsatop.cw.frag"
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,FT_UINT8 ,BASE_DEC ,VALS(pwc_vals_cw_frag)
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,0xc0 ,NULL ,HFILL }}
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,{&hf_cw_len, {"Length" ,"pwsatop.cw.length"
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,FT_UINT8 ,BASE_DEC ,NULL
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,0x3f ,NULL ,HFILL }}
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,{&hf_cw_seq, {"Sequence number" ,"pwsatop.cw.seqno"
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,FT_UINT16 ,BASE_DEC ,NULL
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,0 ,NULL ,HFILL }}
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,{&hf_payload ,{"TDM payload" ,"pwsatop.payload"
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,FT_BYTES ,BASE_NONE ,NULL
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,0 ,NULL ,HFILL }}
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,{&hf_payload_l ,{"TDM payload length" ,"pwsatop.payload.len"
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,FT_INT32 ,BASE_DEC ,NULL
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,0 ,NULL ,HFILL }}
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};
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static gint *ett_array[] = {
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&ett
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};
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proto = proto_register_protocol(pwc_longname_pw_satop, shortname, "pwsatopcw");
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proto_register_field_array(proto, hf, array_length(hf));
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proto_register_subtree_array(ett_array, array_length(ett_array));
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register_dissector("pw_satop_mpls", dissect_pw_satop_mpls, proto);
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register_dissector("pw_satop_udp", dissect_pw_satop_udp, proto);
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return;
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}
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void proto_reg_handoff_pw_satop(void)
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{
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data_handle = find_dissector("data");
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pw_padding_handle = find_dissector("pw_padding");
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dissector_add_uint("mpls.label", MPLS_LABEL_INVALID, find_dissector("pw_satop_mpls"));
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dissector_add_handle("udp.port", find_dissector("pw_satop_udp")); /* for Decode-As */
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}
|