478 lines
15 KiB
C
478 lines
15 KiB
C
/* packet-pw-satop.c
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* Routines for CESoPSN PW dissection as per RFC5086.
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* Copyright 2009, Dmitry Trebich, Artem Tamazov <artem.tamazov@tellabs.com>
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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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* 16.03.2009 initial implementation for MPLS
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* 14.08.2009 added: support for IP/UDP demultiplexing
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* Not supported yet:
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* - All PW modes, except Basic NxDS0 mode.
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* - <Optional> RTP Headers (RFC3550)
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* - Decoding of PW payload
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*/
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#include "config.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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void proto_register_pw_cesopsn(void);
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void proto_reg_handoff_pw_cesopsn(void);
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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_lm = -1;
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static int hf_cw_r = -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 expert_field ei_payload_size_invalid_undecoded = EI_INIT;
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static expert_field ei_cw_frg = EI_INIT;
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static expert_field ei_payload_size_invalid_error = EI_INIT;
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static expert_field ei_cw_bits03 = EI_INIT;
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static expert_field ei_pref_cw_len = EI_INIT;
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static expert_field ei_cw_lm = EI_INIT;
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static expert_field ei_packet_size_too_small = EI_INIT;
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static dissector_handle_t pw_padding_handle;
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static dissector_handle_t pw_cesopsn_udp_handle;
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const char pwc_longname_pw_cesopsn[] = "CESoPSN basic NxDS0 mode (no RTP support)";
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static const char shortname[] = "CESoPSN basic (no RTP)";
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static const value_string vals_cw_lm[] = {
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/* note that bitmask in hs_register_info is 0xb == 1011B */
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/* this is why 0x8 comes just after 0x3 */
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{ 0x0, "Normal situation - no AC faults" },
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/*{ 0x1, "Reserved combination" },*/
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{ 0x2, "AC Fault - RDI condition" },
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{ 0x3, "Reserved for CESoPSN signaling" },
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{ 0x8, "AC Fault - TDM data is invalid" },
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/*{ 0x9, "Reserved combination" },*/
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/*{ 0xa, "Reserved combination" },*/
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/*{ 0xb, "Reserved combination" },*/
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{ 0, NULL }
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};
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static
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void dissect_pw_cesopsn( 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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int 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, &ei_packet_size_too_small,
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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 = PWC_PACKET_PROPERTIES_T_INITIALIZER;
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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, 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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/* RFC5086:
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* [LEN (bits (10 to 15) MAY be used to carry the length of the CESoPSN
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* packet (defined as the size of the CESoPSN header + the payload size)
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* if it is less than 64 bytes, and MUST be set to zero otherwise.
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* Note: If fixed RTP header is used in the encapsulation, it is
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* considered part of the CESoPSN header.]
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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 RFC5086'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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{
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guint8 cw_lm;
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cw_lm = tvb_get_guint8(tvb_original, 0) & 0x0b /*l+mod*/;
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if (NULL == try_val_to_str(cw_lm, vals_cw_lm))
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{
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properties |= PWC_CW_SUSPECT_LM;
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}
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{
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guint8 l_bit, m_bits;
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l_bit = (cw_lm & 0x08) >> 3;
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m_bits = (cw_lm & 0x03) >> 0;
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if ((l_bit == 0 && m_bits == 0x0) /*CESoPSN data packet - normal situation*/
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||(l_bit == 0 && m_bits == 0x2) /*CESoPSN data packet - RDI on the AC*/ )
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{
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if ((payload_size == 0) || ((payload_size % 8) != 0))
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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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else if (l_bit == 1 && m_bits == 0x0) /*TDM data is invalid; payload MAY be omitted*/
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{
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/*allow any size of payload*/
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}
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else /*reserved combinations*/
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{
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/*allow any size of payload*/
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}
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}
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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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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_set_str(pinfo->cinfo, COL_INFO, "CW:Bad, ");
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}
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else if (properties & PWC_ANYOF_CW_SUSPECT)
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{
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col_append_str(pinfo->cinfo, COL_INFO, "CW:Suspect, ");
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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:Bad, ");
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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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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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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_length(tvb_original, 0, 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(item, 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(pinfo, item3, &ei_cw_bits03);
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}
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item3 = proto_tree_add_item(tree3, hf_cw_lm, tvb, 0, 1, ENC_BIG_ENDIAN);
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if (properties & PWC_CW_SUSPECT_LM)
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{
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expert_add_info(pinfo, item3, &ei_cw_lm);
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}
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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_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(pinfo, item3, &ei_cw_frg);
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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, &ei_pref_cw_len,
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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, &ei_pref_cw_len,
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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, &ei_pref_cw_len,
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"Bad Length: must be 0 if CESoPSN 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 (payload_size == 0)
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{
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if (properties & PWC_PAY_SIZE_BAD)
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{
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expert_add_info_format(pinfo, item, &ei_payload_size_invalid_error,
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"CESoPSN payload: none found. Size of payload must be <> 0");
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}
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else
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{
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expert_add_info_format(pinfo, item, &ei_payload_size_invalid_undecoded,
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"CESoPSN payload: omitted to conserve bandwidth");
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}
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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_length(tvb_original, PWC_SIZEOF_CW, 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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if (properties & PWC_PAY_SIZE_BAD)
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{
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expert_add_info_format(pinfo, item2, &ei_payload_size_invalid_error,
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"CESoPSN packet payload size must be multiple of 8");
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}
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tree2 = proto_item_add_subtree(item2, ett);
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call_data_dissector(tvb, pinfo, tree2);
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item2 = proto_tree_add_int(tree2, 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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/* 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_length_caplen(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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int dissect_pw_cesopsn_mpls( tvbuff_t * tvb_original, packet_info * pinfo, proto_tree * tree, void* data _U_)
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{
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dissect_pw_cesopsn(tvb_original,pinfo,tree,PWC_DEMUX_MPLS);
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return tvb_captured_length(tvb_original);
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}
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static
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int dissect_pw_cesopsn_udp( tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree, void* data _U_)
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{
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dissect_pw_cesopsn(tvb,pinfo,tree,PWC_DEMUX_UDP);
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return tvb_captured_length(tvb);
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}
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void proto_register_pw_cesopsn(void)
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{
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static hf_register_info hf[] = {
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{ &hf_cw ,{"Control Word" ,"pwcesopsn.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" ,"pwcesopsn.cw.bits03"
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,FT_UINT8 ,BASE_DEC ,NULL
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,0xf0 ,NULL ,HFILL }},
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{ &hf_cw_lm, {"L+M bits" ,"pwcesopsn.cw.lm"
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,FT_UINT8 ,BASE_HEX ,VALS(vals_cw_lm)
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,0x0b ,NULL ,HFILL }},
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{&hf_cw_r, {"R bit: Local CE-bound IWF" ,"pwcesopsn.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_frg, {"Fragmentation" ,"pwcesopsn.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" ,"pwcesopsn.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" ,"pwcesopsn.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" ,"pwcesopsn.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" ,"pwcesopsn.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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static ei_register_info ei[] = {
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{ &ei_packet_size_too_small, { "pwcesopsn.packet_size_too_small", PI_MALFORMED, PI_ERROR, "PW packet size is too small to carry sensible information", EXPFILL }},
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{ &ei_cw_bits03, { "pwcesopsn.cw.bits03.not_zero", PI_MALFORMED, PI_ERROR, "Bits 0..3 of Control Word must be 0", EXPFILL }},
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{ &ei_cw_lm, { "pwcesopsn.cw.lm.reserved", PI_UNDECODED, PI_WARN, "Reserved combination of L and Modifier bits", EXPFILL }},
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{ &ei_cw_frg, { "pwcesopsn.cw.frag.not_allowed", PI_MALFORMED, PI_ERROR, "Fragmentation of payload is not allowed for basic CESoPSN mode", EXPFILL }},
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{ &ei_pref_cw_len, { "pwcesopsn.cw.length.invalid", PI_MALFORMED, PI_ERROR, "Bad Length: too small", EXPFILL }},
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{ &ei_payload_size_invalid_error, { "pwcesopsn.payload.size_invalid", PI_MALFORMED, PI_ERROR, "CESoPSN payload size invalid", EXPFILL }},
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{ &ei_payload_size_invalid_undecoded, { "pwcesopsn.payload.undecoded", PI_UNDECODED, PI_NOTE, "CESoPSN payload: omitted to conserve bandwidth", EXPFILL }},
|
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};
|
|
expert_module_t* expert_pwcesopsn;
|
|
|
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proto = proto_register_protocol(pwc_longname_pw_cesopsn, shortname, "pwcesopsn");
|
|
proto_register_field_array(proto, hf, array_length(hf));
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|
proto_register_subtree_array(ett_array, array_length(ett_array));
|
|
expert_pwcesopsn = expert_register_protocol(proto);
|
|
expert_register_field_array(expert_pwcesopsn, ei, array_length(ei));
|
|
register_dissector("pw_cesopsn_mpls", dissect_pw_cesopsn_mpls, proto);
|
|
pw_cesopsn_udp_handle = register_dissector("pw_cesopsn_udp", dissect_pw_cesopsn_udp, proto);
|
|
}
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|
|
|
|
|
void proto_reg_handoff_pw_cesopsn(void)
|
|
{
|
|
dissector_handle_t pw_cesopsn_mpls_handle;
|
|
|
|
pw_padding_handle = find_dissector_add_dependency("pw_padding", proto);
|
|
|
|
/* For Decode As */
|
|
pw_cesopsn_mpls_handle = create_dissector_handle( dissect_pw_cesopsn_mpls, proto );
|
|
dissector_add_for_decode_as("mpls.label", pw_cesopsn_mpls_handle);
|
|
|
|
dissector_add_for_decode_as_with_preference("udp.port", pw_cesopsn_udp_handle);
|
|
}
|
|
|
|
/*
|
|
* 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:
|
|
*/
|