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wireshark/epan/dissectors/packet-mdshdr.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

368 lines
14 KiB
C
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/* packet-mdshdr.c
* Routines for dissection of Cisco MDS Switch Internal Header
* Copyright 2001, Dinesh G Dutt <ddutt@andiamo.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.
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/etypes.h>
#include <epan/prefs.h>
#include "packet-fc.h"
void proto_register_mdshdr(void);
void proto_reg_handoff_mdshdr(void);
#define MDSHDR_VERSION_OFFSET 0
/* Mdshdr Control bits */
#define MDSHDR_CTL_IDXDIRECT 1
#define MDSHDR_CTL_IGNACLO 2
#define MDSHDR_CTL_DRP 4
/* OFFSETS OF FIELDS */
#define MDSHDR_VER_OFFSET 0
#define MDSHDR_SOF_OFFSET 1
#define MDSHDR_PKTLEN_OFFSET 2
#define MDSHDR_DIDX_OFFSET 5
#define MDSHDR_SIDX_OFFSET 6
#define MDSHDR_VSAN_OFFSET 13
/* Two size definitions are sufficient */
#define MDSHDR_SIZE_BYTE sizeof(gchar)
#define MDSHDR_SIZE_INT16 sizeof(guint16)
#define MDSHDR_SIZE_INT32 sizeof(guint32)
/* Other miscellaneous defines; can't rely on sizeof structs */
#define MDSHDR_MAX_VERSION 0
#define MDSHDR_HEADER_SIZE 16
#define MDSHDR_TRAILER_SIZE 6
/* SOF Encodings */
#define MDSHDR_SOFc1 0x1
#define MDSHDR_SOFi1 0x2
#define MDSHDR_SOFn1 0x3
#define MDSHDR_SOFi2 0x4
#define MDSHDR_SOFn2 0x5
#define MDSHDR_SOFi3 0x6
#define MDSHDR_SOFn3 0x7
#define MDSHDR_SOFf 0x8
#define MDSHDR_SOFc4 0x9
#define MDSHDR_SOFi4 0xa
#define MDSHDR_SOFn4 0xb
/* EOF Encodings */
#define MDSHDR_EOFt 0x1
#define MDSHDR_EOFdt 0x2
#define MDSHDR_EOFa 0x4
#define MDSHDR_EOFn 0x3
#define MDSHDR_EOFdti 0x6
#define MDSHDR_EOFni 0x7
#define MDSHDR_EOFrt 0xa
#define MDSHDR_EOFrti 0xe
#define MDSHDR_EOF_UNKNOWN 0xb
/* Initialize the protocol and registered fields */
static int proto_mdshdr = -1;
static int hf_mdshdr_sof = -1;
static int hf_mdshdr_pkt_len = -1;
static int hf_mdshdr_dstidx = -1;
static int hf_mdshdr_srcidx = -1;
static int hf_mdshdr_vsan = -1;
static int hf_mdshdr_eof = -1;
static int hf_mdshdr_no_trailer = -1;
static int hf_mdshdr_span = -1;
static int hf_mdshdr_fccrc = -1;
/* Initialize the subtree pointers */
static gint ett_mdshdr = -1;
static gint ett_mdshdr_hdr = -1;
static gint ett_mdshdr_trlr = -1;
static dissector_handle_t fc_dissector_handle;
static gboolean decode_if_zero_etype = FALSE;
static const value_string sof_vals[] = {
{MDSHDR_SOFc1, "SOFc1"},
{MDSHDR_SOFi1, "SOFi1"},
{MDSHDR_SOFn1, "SOFn1"},
{MDSHDR_SOFi2, "SOFi2"},
{MDSHDR_SOFn2, "SOFn2"},
{MDSHDR_SOFi3, "SOFi3"},
{MDSHDR_SOFn3, "SOFn3"},
{MDSHDR_SOFc4, "SOFc4"},
{MDSHDR_SOFi4, "SOFi4"},
{MDSHDR_SOFn4, "SOFn4"},
{MDSHDR_SOFf, "SOFf"},
{0, NULL},
};
static const value_string eof_vals[] = {
{MDSHDR_EOFt, "EOFt"},
{MDSHDR_EOFdt, "EOFdt"},
{MDSHDR_EOFa, "EOFa"},
{MDSHDR_EOFn, "EOFn"},
{MDSHDR_EOFdti, "EOFdti"},
{MDSHDR_EOFni, "EOFni"},
{MDSHDR_EOFrt, "EOFrt"},
{MDSHDR_EOFrti, "EOFrti"},
/*{MDSHDR_EOF_UNKNOWN, ""}, intentionally removed*/
{0, NULL},
};
static int
dissect_mdshdr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
/* Set up structures needed to add the protocol subtree and manage it */
proto_item *ti_main;
proto_item *hidden_item;
proto_tree *mdshdr_tree_main, *mdshdr_tree_hdr, *mdshdr_tree_trlr;
int offset = 0;
guint pktlen;
tvbuff_t *next_tvb;
guint8 sof, eof;
int trailer_start = 0; /*0 means "no trailer found"*/
fc_data_t fc_data;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "MDS Header");
col_clear(pinfo->cinfo, COL_INFO);
sof = tvb_get_guint8(tvb, offset+MDSHDR_SOF_OFFSET) & 0x0F;
pktlen = tvb_get_ntohs(tvb, offset+MDSHDR_PKTLEN_OFFSET) & 0x1FFF;
/* The Mdshdr trailer is at the end of the frame */
if ((tvb_captured_length(tvb) >= (MDSHDR_HEADER_SIZE + pktlen))
/* Avoid header/trailer overlap if something wrong */
&& (pktlen >= MDSHDR_TRAILER_SIZE)) {
trailer_start = MDSHDR_HEADER_SIZE + pktlen - MDSHDR_TRAILER_SIZE;
eof = tvb_get_guint8(tvb, trailer_start);
tvb_set_reported_length(tvb, MDSHDR_HEADER_SIZE+pktlen);
}
else {
eof = MDSHDR_EOF_UNKNOWN;
}
fc_data.sof_eof = 0;
if ((sof == MDSHDR_SOFi3) || (sof == MDSHDR_SOFi2) || (sof == MDSHDR_SOFi1)
|| (sof == MDSHDR_SOFi4)) {
fc_data.sof_eof = FC_DATA_SOF_FIRST_FRAME;
}
else if (sof == MDSHDR_SOFf) {
fc_data.sof_eof = FC_DATA_SOF_SOFF;
}
if (eof != MDSHDR_EOFn) {
fc_data.sof_eof |= FC_DATA_EOF_LAST_FRAME;
}
else if (eof != MDSHDR_EOFt) {
fc_data.sof_eof |= FC_DATA_EOF_INVALID;
}
if (tree) {
ti_main = proto_tree_add_protocol_format(tree, proto_mdshdr, tvb, 0,
MDSHDR_HEADER_SIZE+pktlen,
"MDS Header(%s/%s)",
val_to_str(sof, sof_vals, "Unknown(%u)"),
val_to_str(eof, eof_vals, "Unknown(%u)"));
mdshdr_tree_main = proto_item_add_subtree(ti_main, ett_mdshdr);
/* Add Header part as subtree first */
mdshdr_tree_hdr = proto_tree_add_subtree(mdshdr_tree_main, tvb, MDSHDR_VER_OFFSET,
MDSHDR_HEADER_SIZE, ett_mdshdr_hdr, NULL, "MDS Header");
hidden_item = proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_sof, tvb, MDSHDR_SOF_OFFSET,
MDSHDR_SIZE_BYTE, ENC_BIG_ENDIAN);
PROTO_ITEM_SET_HIDDEN(hidden_item);
proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_pkt_len, tvb, MDSHDR_PKTLEN_OFFSET,
MDSHDR_SIZE_INT16, ENC_BIG_ENDIAN);
proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_dstidx, tvb, MDSHDR_DIDX_OFFSET,
MDSHDR_SIZE_INT16, ENC_BIG_ENDIAN);
proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_srcidx, tvb, MDSHDR_SIDX_OFFSET,
MDSHDR_SIZE_INT16, ENC_BIG_ENDIAN);
proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_vsan, tvb, MDSHDR_VSAN_OFFSET,
MDSHDR_SIZE_INT16, ENC_BIG_ENDIAN);
hidden_item = proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_span,
tvb, MDSHDR_VSAN_OFFSET,
MDSHDR_SIZE_INT16, ENC_BIG_ENDIAN);
PROTO_ITEM_SET_HIDDEN(hidden_item);
/* Add Mdshdr Trailer part */
if (tvb_reported_length(tvb) >= MDSHDR_HEADER_SIZE + pktlen
&& 0 != trailer_start) {
mdshdr_tree_trlr = proto_tree_add_subtree(mdshdr_tree_main, tvb, trailer_start,
MDSHDR_TRAILER_SIZE,
ett_mdshdr_trlr, NULL, "MDS Trailer");
proto_tree_add_item(mdshdr_tree_trlr, hf_mdshdr_eof, tvb,
trailer_start, MDSHDR_SIZE_BYTE, ENC_BIG_ENDIAN);
proto_tree_add_item(mdshdr_tree_trlr, hf_mdshdr_fccrc, tvb,
trailer_start+2, MDSHDR_SIZE_INT32, ENC_BIG_ENDIAN);
}
else {
proto_tree_add_item(mdshdr_tree_main, hf_mdshdr_no_trailer, tvb, 0, 0, ENC_NA);
}
}
if (tvb_reported_length(tvb) >= MDSHDR_HEADER_SIZE + pktlen
&& 0 != pktlen /*if something wrong*/) {
next_tvb = tvb_new_subset_length(tvb, MDSHDR_HEADER_SIZE, pktlen);
/* XXX what to do with the rest of this frame? --ArtemTamazov */
}
else {
next_tvb = tvb_new_subset_remaining(tvb, MDSHDR_HEADER_SIZE);
}
/* Call the Fibre Channel dissector */
if (fc_dissector_handle) {
fc_data.ethertype = ETHERTYPE_FCFT;
call_dissector_with_data(fc_dissector_handle, next_tvb, pinfo, tree, &fc_data);
}
else {
call_data_dissector(next_tvb, pinfo, tree);
}
return tvb_captured_length(tvb);
}
void
proto_register_mdshdr(void)
{
static hf_register_info hf[] = {
{ &hf_mdshdr_sof,
{"SOF", "mdshdr.sof", FT_UINT8, BASE_DEC, VALS(sof_vals), 0x0, NULL, HFILL}},
{ &hf_mdshdr_pkt_len,
{"Packet Len", "mdshdr.plen", FT_UINT16, BASE_DEC, NULL, 0x1FFF, NULL, HFILL}},
{ &hf_mdshdr_dstidx,
{"Dst Index", "mdshdr.dstidx", FT_UINT16, BASE_HEX, NULL, 0xFFC, NULL, HFILL}},
{ &hf_mdshdr_srcidx,
{"Src Index", "mdshdr.srcidx", FT_UINT16, BASE_HEX, NULL, 0x3FF, NULL, HFILL}},
{ &hf_mdshdr_vsan,
{"VSAN", "mdshdr.vsan", FT_UINT16, BASE_DEC, NULL, 0x0FFF, NULL, HFILL}},
{ &hf_mdshdr_eof,
{"EOF", "mdshdr.eof", FT_UINT8, BASE_DEC, VALS(eof_vals), 0x0, NULL, HFILL}},
{ &hf_mdshdr_no_trailer,
{"MDS Trailer: Not Found", "mdshdr.no_trailer", FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL}},
{ &hf_mdshdr_span,
{"SPAN Frame", "mdshdr.span", FT_UINT16, BASE_DEC, NULL, 0xF000, NULL, HFILL}},
{ &hf_mdshdr_fccrc,
{"CRC", "mdshdr.crc", FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL}},
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_mdshdr,
&ett_mdshdr_hdr,
&ett_mdshdr_trlr
};
module_t *mdshdr_module;
/* Register the protocol name and description */
proto_mdshdr = proto_register_protocol("MDS Header", "MDS Header", "mdshdr");
proto_register_field_array(proto_mdshdr, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
mdshdr_module = prefs_register_protocol(proto_mdshdr, proto_reg_handoff_mdshdr);
prefs_register_bool_preference(mdshdr_module, "decode_if_etype_zero",
"Decode as MDS Header if Ethertype == 0",
"A frame is considered for decoding as MDSHDR if either "
"ethertype is 0xFCFC or zero. Turn this flag off if you "
"don't want ethertype zero to be decoded as MDSHDR. "
"This might be useful to avoid problems with test frames.",
&decode_if_zero_etype);
}
void
proto_reg_handoff_mdshdr(void)
{
static dissector_handle_t mdshdr_handle;
static gboolean registered_for_zero_etype = FALSE;
static gboolean mdshdr_prefs_initialized = FALSE;
if (!mdshdr_prefs_initialized) {
/*
* This is the first time this has been called (i.e.,
* Wireshark/TShark is starting up), so create a handle for
* the MDS Header dissector, register the dissector for
* ethertype ETHERTYPE_FCFT, and fetch the data and Fibre
* Channel handles.
*/
mdshdr_handle = create_dissector_handle(dissect_mdshdr, proto_mdshdr);
dissector_add_uint("ethertype", ETHERTYPE_FCFT, mdshdr_handle);
fc_dissector_handle = find_dissector_add_dependency("fc", proto_mdshdr);
mdshdr_prefs_initialized = TRUE;
}
/*
* Only register the dissector for ethertype 0 if the preference
* is set to do so.
*/
if (decode_if_zero_etype) {
/*
* The preference to register for ethertype ETHERTYPE_UNK (0)
* is set; if we're not registered for ethertype ETHERTYPE_UNK,
* do so.
*/
if (!registered_for_zero_etype) {
dissector_add_uint("ethertype", ETHERTYPE_UNK, mdshdr_handle);
registered_for_zero_etype = TRUE;
}
} else {
/*
* The preference to register for ethertype ETHERTYPE_UNK (0)
* is not set; if we're registered for ethertype ETHERTYPE_UNK,
* undo that registration.
*/
if (registered_for_zero_etype) {
dissector_delete_uint("ethertype", ETHERTYPE_UNK, mdshdr_handle);
registered_for_zero_etype = FALSE;
}
}
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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