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wireshark/epan/dissectors/packet-gfp.c

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/* packet-gfp.c
* Routines for Generic Framing Procedure dissection
* Copyright 2015, John Thacker <johnthacker@gmail.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.
*/
/*
* Generic Framing Procedure (GFP) is used to map octet-aligned variable
* length payloads (e.g. Ethernet, MPLS, octet-aligned PPP, IP) into
* octet-synchronous signals such as SONET/SDH (ITU-T G.707) and OTN
* (ITU-T G.709). GFP is a telecommunications industry standard defined in
* ITU-T G.7041/Y.1303.
*
* Reference:
* https://www.itu.int/rec/T-REC-G.7041/
*/
#include <config.h>
#include <epan/packet.h> /* Should be first Wireshark include (other than config.h) */
#include <epan/expert.h>
#include <epan/prefs.h>
#include <epan/crc16-tvb.h>
#include <epan/crc32-tvb.h>
#include <epan/decode_as.h>
#include <epan/proto_data.h>
#include <wiretap/wtap.h>
/* Prototypes */
/* (Required to prevent [-Wmissing-prototypes] warnings */
void proto_reg_handoff_gfp(void);
void proto_register_gfp(void);
/* Initialize the protocol and registered fields */
static int proto_gfp = -1;
static int hf_gfp_pli = -1;
static int hf_gfp_chec = -1;
static int hf_gfp_chec_status = -1;
static int hf_gfp_type = -1;
static int hf_gfp_pti = -1;
static int hf_gfp_pfi = -1;
static int hf_gfp_exi = -1;
static int hf_gfp_upi_data = -1;
static int hf_gfp_upi_management = -1;
static int hf_gfp_thec = -1;
static int hf_gfp_thec_status = -1;
static int hf_gfp_cid = -1;
static int hf_gfp_ehec = -1;
static int hf_gfp_ehec_status = -1;
static int hf_gfp_fcs = -1;
static int hf_gfp_fcs_good = -1;
static int hf_gfp_fcs_bad = -1;
static expert_field ei_gfp_pli_idle_nonempty = EI_INIT;
static expert_field ei_gfp_pli_unknown = EI_INIT;
static expert_field ei_gfp_pli_invalid = EI_INIT;
static expert_field ei_gfp_chec_bad = EI_INIT;
static expert_field ei_gfp_thec_bad = EI_INIT;
static expert_field ei_gfp_ehec_bad = EI_INIT;
static expert_field ei_gfp_exi_short = EI_INIT;
static expert_field ei_gfp_pfi_short = EI_INIT;
static expert_field ei_gfp_payload_undecoded = EI_INIT;
static expert_field ei_gfp_fcs_bad = EI_INIT;
#define GFP_USER_DATA 0
#define GFP_CLIENT_MANAGEMENT 4
#define GFP_MANAGEMENT_COMMUNICATIONS 5
#define GFP_EXT_NULL 0
#define GFP_EXT_LINEAR 1
#define GFP_EXT_RING 2
/* Initialize the subtree pointers */
static gint ett_gfp = -1;
static gint ett_gfp_type = -1;
static gint ett_gfp_fcs = -1;
static dissector_table_t gfp_dissector_table;
/* ITU-T G.7041 6.1.1, 6.2 */
static const range_string gfp_pli_rvals[] = {
{0, 0, "Idle Frame"},
{1, 3, "Control Frame (Reserved)"},
{4, G_MAXUINT16, "Client Frame"},
{0, 0, NULL}
};
static const int *gfp_type_data_fields[] = {
&hf_gfp_pti,
&hf_gfp_pfi,
&hf_gfp_exi,
&hf_gfp_upi_data,
NULL
};
static const int *gfp_type_management_fields[] = {
&hf_gfp_pti,
&hf_gfp_pfi,
&hf_gfp_exi,
&hf_gfp_upi_management,
NULL
};
static const value_string gfp_pti_vals[] = {
{GFP_USER_DATA, "User Data"},
{GFP_CLIENT_MANAGEMENT, "Client Management"},
{GFP_MANAGEMENT_COMMUNICATIONS, "Management Communications"},
{0, NULL}
};
static const value_string gfp_exi_vals[] = {
{GFP_EXT_NULL, "Null Extension Header"},
{GFP_EXT_LINEAR, "Linear Frame"},
{GFP_EXT_RING, "Ring Frame"},
{0, NULL}
};
static const range_string gfp_upi_data_rvals[] = {
{0, 0, "Reserved and not available"},
{1, 1, "Frame-Mapped Ethernet"},
{2, 2, "Frame-Mapped PPP"},
{3, 3, "Transparent Fibre Channel"},
{4, 4, "Transparent FICON"},
{5, 5, "Transparent ESCON"},
{6, 6, "Transparent Gbit Ethernet"},
{7, 7, "Reserved"},
{8, 8, "Frame-Mapped Multiple Access Protocol over SDH (MAPOS)"},
{9, 9, "Transparent DVB ASI"},
{10, 10, "Frame-Mapped IEEE 802.17 Resilient Packet Ring"},
{11, 11, "Frame-Mapped Fibre Channel FC-BBW"},
{12, 12, "Asycnchronous Transparent Fibre Channel"},
{13, 13, "Frame-Mapped MPLS"},
{14, 14, "Frame-Mapped MPLS (Multicast) [Deprecrated]"},
{15, 15, "Frame-Mapped OSI network layer protocols (IS-IS, ES-IS, CLNP)"},
{16, 16, "Frame-Mapped IPv4"},
{17, 17, "Frame-Mapped IPv6"},
{18, 18, "Frame-Mapped DVB-ASI"},
{19, 19, "Frame-Mapped 64B/66B encoded Ethernet, including frame preamble"},
{20, 20, "Frame-Mapped 64B/66B encoded Ethernet ordered set information"},
{21, 21, "Transparent transcoded FC-1200"},
/*UPI value 22 & 23 from Amendment 3 (01/2015)*/
{22, 22, "Precision Time Protocol message"},
{23, 23, "Synchronization status message"},
{24, 239, "Reserved for future standardization"},
{240, 252, "Reserved for proprietary use"},
{253, 253, "Reserved for proprietary use, formerly Frame-Mapped 64B/66B encoded Ethernet, including frame preamble"},
{254, 254, "Reserved for proprietary use, formerly Frame-Mapped 64B/66B encoded Ethernet ordered set information"},
{255, 255, "Reserved and not available"},
{0, 0, NULL }
};
static const range_string gfp_upi_management_rvals[] = {
{0, 0, "Reserved and not available"},
{1, 1, "Client Signal Fail (Loss of Client Signal)"},
{2, 2, "Client Signal Fail (Loss of Character Synchronisation)"},
{3, 3, "Defect Clear Indication (DCI)"},
{4, 4, "Forward Defect Indication (FDI)"},
{5, 5, "Reverse Defect Indication (RDI)"},
{6, 223, "Reserved for future use"},
{224, 254, "Reserved for proprietary use"},
{255, 255, "Reserved and not available"},
{0, 0, NULL}
};
/* Even GFP idle frames must have 4 bytes for the core header.
* If data is received with fewer than this it is rejected. */
#define GFP_MIN_LENGTH 4
static void gfp_prompt(packet_info *pinfo, gchar* result)
{
g_snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "UPI %u as",
GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, proto_gfp, 0)));
}
static gpointer gfp_value(packet_info *pinfo)
{
return p_get_proto_data(pinfo->pool, pinfo, proto_gfp, 0);
}
/* GFP has several identical 16 bit CRCs in its header (HECs). Note that
* this function increases the offset. */
static void
gfp_add_hec_tree(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint *offset, const guint len, const int field, const int field_status, expert_field *ei_bad)
{
guint hec_calc;
hec_calc = crc16_r3_ccitt_tvb(tvb, *offset, len);
*offset += len;
proto_tree_add_checksum(tree, tvb, *offset, field, field_status, ei_bad, pinfo, hec_calc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
*offset += 2;
}
/* G.7041 6.1.2 GFP payload area */
static void
dissect_gfp_payload(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_tree *gfp_tree, guint *offset, guint payload_len)
{
tvbuff_t *payload_tvb;
proto_item *type_ti = NULL;
proto_item *fcs_ti;
proto_tree *fcs_tree = NULL;
guint pti, pfi, exi, upi;
guint fcs, fcs_calc;
guint fcs_len = 0;
/* G.7041 6.1.2.3 Payload area scrambling
* Note that payload when sent on the wire is scrambled as per ATM
* with a 1 + x^43 multiplicative scrambler. Likely already removed by
* the time we get a capture file (as with ATM). Could have a pref,
* but if it's present we have to save state over subsequent frames,
* always would fail to decode the first 43 payload bytes of a capture. */
/* G.7041 6.1.2.1 Payload Header - at least 4 bytes */
tvb_ensure_bytes_exist(tvb, *offset, 4);
payload_len -= 4;
/* G.7041 6.1.2.1.1 GFP type field - mandatory 2 bytes */
pti = tvb_get_bits8(tvb, 8*(*offset), 3);
pfi = tvb_get_bits8(tvb, 8*(*offset)+3, 1);
exi = tvb_get_bits8(tvb, 8*(*offset)+4, 4);
upi = tvb_get_guint8(tvb, *offset+1);
p_add_proto_data(pinfo->pool, pinfo, proto_gfp, 0, GUINT_TO_POINTER(upi));
col_add_str(pinfo->cinfo, COL_INFO, val_to_str(pti, gfp_pti_vals, "Reserved PTI (%d)"));
if (pti == GFP_USER_DATA ||
pti == GFP_MANAGEMENT_COMMUNICATIONS) {
/* G.7041 Table 6-3 - GFP_MANAGEMENT_COMMUNICATIONS
* uses the same UPI table as USER_DATA, though
* "not all of these UPI types are applicable" in that case. */
type_ti = proto_tree_add_bitmask_with_flags(gfp_tree, tvb, *offset, hf_gfp_type,
ett_gfp_type, gfp_type_data_fields, ENC_BIG_ENDIAN, BMT_NO_FLAGS);
col_append_sep_str(pinfo->cinfo, COL_INFO, ": ", rval_to_str(upi, gfp_upi_data_rvals, "Unknown 0x%02x"));
} else if (pti == GFP_CLIENT_MANAGEMENT) {
/* G.7041 Table 6-4 */
type_ti = proto_tree_add_bitmask_with_flags(gfp_tree, tvb, *offset, hf_gfp_type,
ett_gfp_type, gfp_type_management_fields, ENC_BIG_ENDIAN, BMT_NO_FLAGS);
col_append_sep_str(pinfo->cinfo, COL_INFO, ": ", rval_to_str(upi, gfp_upi_management_rvals, "Unknown 0x%02x"));
}
/* G.7041 6.1.2.1.2 Type HEC (tHEC) - mandatory 2 bytes */
gfp_add_hec_tree(tvb, pinfo, gfp_tree, offset, 2, hf_gfp_thec, hf_gfp_thec_status, &ei_gfp_thec_bad);
switch (exi) {
case GFP_EXT_NULL:
/* G.7041 6.1.2.1.3.1 Null extension header */
break;
case GFP_EXT_LINEAR:
/* G.7041 6.1.2.1.3.2 Extension header for a linear frame */
if (payload_len < 4) {
expert_add_info(pinfo, type_ti, &ei_gfp_exi_short);
payload_len = 0;
}
else {
payload_len -= 4;
}
proto_tree_add_item(gfp_tree, hf_gfp_cid, tvb, *offset, 1, ENC_BIG_ENDIAN);
/* Next byte spare field, reserved */
/* 6.1.2.1.4 Extension HEC field */
gfp_add_hec_tree(tvb, pinfo, gfp_tree, offset, 2, hf_gfp_ehec, hf_gfp_ehec_status, &ei_gfp_ehec_bad);
break;
case GFP_EXT_RING:
/* 6.1.2.1.3.3 Extension header for a ring frame */
/* "For further study." Undefined so fall through */
default:
/* Reserved */
/* TODO: Mark as error / unhandled? */
break;
}
proto_item_set_end(gfp_tree, tvb, *offset);
if (pfi == 1) { /* 6.1.2.2.1 Payload FCS field present */
if (payload_len < 4) {
expert_add_info(pinfo, type_ti, &ei_gfp_pfi_short);
fcs_len = payload_len;
payload_len = 0;
} else {
fcs_len = 4;
payload_len -= 4;
}
proto_tree_set_appendix(gfp_tree, tvb, *offset + payload_len, fcs_len);
fcs = tvb_get_ntohl(tvb, *offset + payload_len);
/* Same CRC32 as ATM */
/* As with ATM, we can either compute the CRC as it would be
* calculated and compare (last step involves taking the complement),
* or we can include the passed CRC in the input and check to see
* if the remainder is a known value. I like the first method
* only because it lets us display what we should have received. */
/* Method 1: */
fcs_calc = crc32_mpeg2_tvb_offset(tvb, *offset, payload_len);
if (fcs == ~fcs_calc) {
fcs_ti = proto_tree_add_uint_format_value(gfp_tree, hf_gfp_fcs, tvb, *offset+payload_len, 4, fcs, "0x%08x [correct]", fcs);
fcs_tree = proto_item_add_subtree(fcs_ti, ett_gfp_fcs);
fcs_ti = proto_tree_add_boolean(fcs_tree, hf_gfp_fcs_good, tvb, *offset+payload_len, 4, TRUE);
PROTO_ITEM_SET_GENERATED(fcs_ti);
fcs_ti = proto_tree_add_boolean(fcs_tree, hf_gfp_fcs_bad, tvb, *offset+payload_len, 4, FALSE);
PROTO_ITEM_SET_GENERATED(fcs_ti);
} else {
fcs_ti = proto_tree_add_uint_format_value(gfp_tree, hf_gfp_fcs, tvb, *offset+payload_len, 4, fcs, "0x%08x [incorrect, should be 0x%08x]", fcs, fcs_calc);
fcs_tree = proto_item_add_subtree(fcs_ti, ett_gfp_fcs);
fcs_ti = proto_tree_add_boolean(fcs_tree, hf_gfp_fcs_good, tvb, *offset+payload_len, 4, FALSE);
PROTO_ITEM_SET_GENERATED(fcs_ti);
fcs_ti = proto_tree_add_boolean(fcs_tree, hf_gfp_fcs_bad, tvb, *offset+payload_len, 4, TRUE);
PROTO_ITEM_SET_GENERATED(fcs_ti);
expert_add_info(pinfo, fcs_ti, &ei_gfp_fcs_bad);
}
/* Method 2: */
/* fcs_calc = crc32_mpeg2_tvb_offset(tvb, *offset, payload_len+4);
fcs_ti = proto_tree_add_uint(gfp_tree, hf_gfp_fcs, tvb, *offset+payload_len, 4, fcs);
proto_item_append_text(fcs_ti, (fcs_calc == 0xC704DD7B) ? " [correct]" : " [incorrect]"); */
}
/* Some client frames we can do. Others are not implemented yet.
* Transparent mode types are much trickier than frame-mapped,
* since they requires reassembling streams across multiple GFP packets. */
payload_tvb = tvb_new_subset_length(tvb, *offset, payload_len);
switch (pti) {
case GFP_USER_DATA:
case GFP_MANAGEMENT_COMMUNICATIONS:
if (!dissector_try_uint(gfp_dissector_table, upi, payload_tvb, pinfo, tree)) {
expert_add_info_format(pinfo, type_ti, &ei_gfp_payload_undecoded, "Payload type 0x%02x (%s) unsupported", upi, rval_to_str_const(upi, gfp_upi_data_rvals, "UNKNOWN"));
call_data_dissector(payload_tvb, pinfo, tree);
}
break;
case GFP_CLIENT_MANAGEMENT:
call_data_dissector(payload_tvb, pinfo, tree);
break;
default:
break;
}
*offset += payload_len;
*offset += fcs_len;
}
static int
dissect_gfp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
void *data _U_)
{
proto_item *ti, *pli_ti;
proto_tree *gfp_tree;
guint offset = 0;
int len = 0;
guint pli;
/*** HEURISTICS ***/
/* Check that the packet is long enough for it to belong to us. */
if (tvb_reported_length(tvb) < GFP_MIN_LENGTH)
return 0;
/*** COLUMN DATA ***/
/* Set the Protocol column to the constant string of GFP */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "GFP");
col_clear(pinfo->cinfo, COL_INFO);
/* Avoid asserts for leaving these blank. */
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A");
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
/*** PROTOCOL TREE ***/
/* create display subtree for the protocol */
ti = proto_tree_add_item(tree, proto_gfp, tvb, 0, GFP_MIN_LENGTH, ENC_NA);
gfp_tree = proto_item_add_subtree(ti, ett_gfp);
/* ITU-T G.7041 6.1.1 GFP core header */
/* The core header could be scrambled (see G.7041 6.1.1.3) but isn't on
* the GFP level capture files I've seen as it's removed before then.
* If using this as a subdissector to a SDH or OTN dissector, that could
* be an issue. TODO: Maybe add a pref for scrambling? */
len = 2;
pli_ti = proto_tree_add_item_ret_uint(gfp_tree, hf_gfp_pli, tvb,
offset, len, ENC_BIG_ENDIAN, &pli);
if (pli < 4) { /* Don't interpret as payload length */
proto_item_append_text(pli_ti, " (%s)", rval_to_str_const(pli, gfp_pli_rvals, "Unknown"));
}
col_set_str(pinfo->cinfo, COL_INFO, rval_to_str_const(pli, gfp_pli_rvals, "Unknown"));
/* 6.1.1.2 Core HEC field */
gfp_add_hec_tree(tvb, pinfo, gfp_tree, &offset, len, hf_gfp_chec, hf_gfp_chec_status, &ei_gfp_chec_bad);
if (pli == 0) { /* 6.2.1 GFP idle frames */
if (tvb_reported_length_remaining(tvb, offset)) {
expert_add_info(pinfo, pli_ti, &ei_gfp_pli_idle_nonempty);
}
} else if (pli < 4) { /* 6.2.2 Other control frames (reserved) */
expert_add_info(pinfo, pli_ti, &ei_gfp_pli_unknown);
} else {
/* G.7041 6.1.2 GFP payload area */
if (tvb_reported_length(tvb) < pli + offset) {
/* avoid signed / unsigned comparison */
proto_item_append_text(pli_ti, " (invalid, reported length is %u)", tvb_reported_length_remaining(tvb, offset));
expert_add_info(pinfo, pli_ti, &ei_gfp_pli_invalid);
}
dissect_gfp_payload(tvb, pinfo, tree, gfp_tree, &offset, pli);
}
/* Return the amount of data this dissector was able to dissect */
return offset;
}
void
proto_register_gfp(void)
{
/* Setup list of header fields See Section 1.5 of README.dissector for
* details. */
static hf_register_info hf[] = {
{ &hf_gfp_pli,
{ "Payload Length Indicator", "gfp.pli", FT_UINT16, BASE_DEC,
NULL, 0x0, NULL, HFILL }
},
{ &hf_gfp_chec,
{ "Core HEC", "gfp.chec", FT_UINT16, BASE_HEX,
NULL, 0x0, NULL, HFILL }
},
{ &hf_gfp_chec_status,
{ "cHEC Status", "gfp.chec.status", FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
NULL, HFILL }
},
{ &hf_gfp_type,
{ "Type Field", "gfp.type", FT_UINT16, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_gfp_pti,
{ "PTI", "gfp.pti", FT_UINT16, BASE_HEX, VALS(gfp_pti_vals),
0xE000, "Payload Type Identifier", HFILL }
},
{ &hf_gfp_pfi,
{ "PFI", "gfp.pfi", FT_BOOLEAN, 16, TFS(&tfs_present_absent),
0x1000, "Payload FCS Indicator", HFILL }
},
{ &hf_gfp_exi,
{ "EXI", "gfp.exi", FT_UINT16, BASE_HEX, VALS(gfp_exi_vals),
0x0F00, "Extension Header Identifier", HFILL }
},
{ &hf_gfp_upi_data,
{ "UPI", "gfp.upi", FT_UINT16, BASE_HEX|BASE_RANGE_STRING,
RVALS(gfp_upi_data_rvals),
0xFF, "User Payload Identifier for Client Data Frame (or Management Communications Frame)", HFILL }
},
{ &hf_gfp_upi_management,
{ "UPI", "gfp.upi", FT_UINT16, BASE_HEX|BASE_RANGE_STRING,
RVALS(gfp_upi_management_rvals),
0xFF, "User Payload Identifier for Client Management Frame", HFILL }
},
{ &hf_gfp_thec,
{ "Type HEC", "gfp.thec", FT_UINT16, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_gfp_thec_status,
{ "tHEC Status", "gfp.thec.status", FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
NULL, HFILL }
},
{ &hf_gfp_cid,
{ "Channel ID", "gfp.cid", FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_gfp_ehec,
{ "Extension HEC", "gfp.ehec", FT_UINT16, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_gfp_ehec_status,
{ "eHEC Status", "gfp.ehec.status", FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
NULL, HFILL }
},
{ &hf_gfp_fcs,
{ "Payload FCS", "gfp.fcs", FT_UINT32, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_gfp_fcs_good,
{ "Good FCS", "gfp.fcs_good", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
"True: FCS matches payload; False: doesn't match", HFILL }
},
{ &hf_gfp_fcs_bad,
{ "Bad eHEC", "gfp.fcs_bad", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
"True: FCS doesn't match payload; False: matches", HFILL }
}
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_gfp,
&ett_gfp_type,
&ett_gfp_fcs
};
/* Setup protocol expert items */
static ei_register_info ei[] = {
{ &ei_gfp_pli_idle_nonempty,
{ "gfp.pli.idle.nonempty", PI_MALFORMED, PI_ERROR,
"Payload present on idle frame", EXPFILL }
},
{ &ei_gfp_pli_unknown,
{ "gfp.pli.unknown", PI_UNDECODED, PI_WARN,
"Unknown control frame type", EXPFILL }
},
{ &ei_gfp_pli_invalid,
{ "gfp.pli.invalid", PI_MALFORMED, PI_WARN,
"Bogus PLI does not match reported length", EXPFILL }
},
{ &ei_gfp_chec_bad,
{ "gfp.chec.bad", PI_CHECKSUM, PI_WARN,
"Bad cHEC", EXPFILL }
},
{ &ei_gfp_thec_bad,
{ "gfp.thec.bad", PI_CHECKSUM, PI_WARN,
"Bad tHEC", EXPFILL }
},
{ &ei_gfp_ehec_bad,
{ "gfp.ehec.bad", PI_CHECKSUM, PI_WARN,
"Bad eHEC", EXPFILL }
},
{ &ei_gfp_exi_short,
{ "gfp.exi.missing", PI_MALFORMED, PI_ERROR,
"EXI bit set but PLI too short for extension header", EXPFILL}
},
{ &ei_gfp_pfi_short,
{ "gfp.pfi.missing", PI_MALFORMED, PI_ERROR,
"PFI bit set but PLI too short for payload FCS", EXPFILL}
},
{ &ei_gfp_payload_undecoded,
{ "gfp.payload.undecoded", PI_UNDECODED, PI_WARN,
"Payload type not supported yet by the dissector", EXPFILL}
},
{ &ei_gfp_fcs_bad,
{ "gfp.fcs.bad", PI_CHECKSUM, PI_WARN,
"Bad FCS", EXPFILL }
}
};
/* Decode As handling */
static build_valid_func gfp_da_build_value[1] = {gfp_value};
static decode_as_value_t gfp_da_values = {gfp_prompt, 1, gfp_da_build_value};
static decode_as_t gfp_da = {"gfp", "GFP", "gfp.upi", 1, 0, &gfp_da_values, NULL, NULL,
decode_as_default_populate_list, decode_as_default_reset, decode_as_default_change, NULL};
/* module_t *gfp_module; */
expert_module_t *expert_gfp;
/* Register the protocol name and description */
proto_gfp = proto_register_protocol("Generic Framing Procedure",
"GFP", "gfp");
/* Required function calls to register the header fields and subtrees */
proto_register_field_array(proto_gfp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* Required function calls to register expert items */
expert_gfp = expert_register_protocol(proto_gfp);
expert_register_field_array(expert_gfp, ei, array_length(ei));
/* Subdissectors for payload */
gfp_dissector_table = register_dissector_table("gfp.upi", "GFP UPI (for Client Data frames)",
proto_gfp, FT_UINT8, BASE_DEC, DISSECTOR_TABLE_NOT_ALLOW_DUPLICATE);
/* Don't register a preferences module yet since there are no prefs in
* order to avoid a warning. (See section 2.6 of README.dissector
* for more details on preferences). */
/*gfp_module = prefs_register_protocol(proto_gfp, NULL);*/
register_decode_as(&gfp_da);
}
/* If this function is registered as a prefs callback (see
* prefs_register_protocol above) this function is also called by Wireshark's
* preferences manager whenever "Apply" or "OK" are pressed. In that case, it
* should accommodate being called more than once by use of the static
* 'initialized' variable included below.
*
* This form of the reg_handoff function is used if if you perform registration
* functions which are dependent upon prefs.
*/
void
proto_reg_handoff_gfp(void)
{
static dissector_handle_t gfp_handle;
gfp_handle = create_dissector_handle(dissect_gfp,
proto_gfp);
dissector_add_uint("wtap_encap", WTAP_ENCAP_GFP_T, gfp_handle);
dissector_add_uint("wtap_encap", WTAP_ENCAP_GFP_F, gfp_handle);
/* Add a few of the easiest UPIs to decode. There's more that probably
* would work, but are untested (frame mapped DVB, frame mapped Fibre
* Channel). The transparent mode ones are trickier, since without a
* one-to-one mapping of frames, we would have to reassemble payload
* packets across multiple GFP packets.
*
* Section 7.1.1 "Ethernet MAC encapsulation" of G.7041 says
* "The Ethernet MAC octets from destination address through
* "frame check sequence, inclusive, are placed in the GFP payload
* "information field.", so we want the dissector for Ethernet
* frames including the FCS. */
dissector_add_uint("gfp.upi", 1, find_dissector("eth_withfcs"));
dissector_add_uint("gfp.upi", 2, find_dissector("ppp_hdlc"));
dissector_add_uint("gfp.upi", 12, find_dissector("mpls"));
dissector_add_uint("gfp.upi", 13, find_dissector("mpls"));
dissector_add_uint("gfp.upi", 16, find_dissector("ip"));
dissector_add_uint("gfp.upi", 17, find_dissector("ipv6"));
}
/*
* Editor modelines - https://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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