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wireshark/epan/dissectors/packet-sdlc.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

220 lines
6 KiB
C
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/* packet-sdlc.c
* Routines for SDLC frame disassembly
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998
*
* 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 <wiretap/wtap.h>
#include <epan/xdlc.h>
/*
* See
*
* http://www.protocols.com/pbook/sna.htm
*/
void proto_register_sdlc(void);
void proto_reg_handoff_sdlc(void);
static int proto_sdlc = -1;
static int hf_sdlc_address = -1;
static int hf_sdlc_control = -1;
static int hf_sdlc_n_r = -1;
static int hf_sdlc_n_s = -1;
static int hf_sdlc_p = -1;
static int hf_sdlc_f = -1;
static int hf_sdlc_s_ftype = -1;
static int hf_sdlc_u_modifier_cmd = -1;
static int hf_sdlc_u_modifier_resp = -1;
static int hf_sdlc_ftype_i = -1;
static int hf_sdlc_ftype_s_u = -1;
static gint ett_sdlc = -1;
static gint ett_sdlc_control = -1;
static dissector_handle_t sna_handle;
static const xdlc_cf_items sdlc_cf_items = {
&hf_sdlc_n_r,
&hf_sdlc_n_s,
&hf_sdlc_p,
&hf_sdlc_f,
&hf_sdlc_s_ftype,
&hf_sdlc_u_modifier_cmd,
&hf_sdlc_u_modifier_resp,
&hf_sdlc_ftype_i,
&hf_sdlc_ftype_s_u
};
static int
dissect_sdlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
proto_tree *sdlc_tree;
proto_item *sdlc_ti;
guint8 addr;
guint16 control;
int sdlc_header_len;
gboolean is_response;
tvbuff_t *next_tvb;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "SDLC");
col_clear(pinfo->cinfo, COL_INFO);
addr = tvb_get_guint8(tvb, 0);
sdlc_header_len = 1; /* address */
/*
* XXX - is there something in the SDLC header that indicates
* how to interpret "command vs. response" based on the
* direction?
*/
if (pinfo->p2p_dir == P2P_DIR_SENT) {
is_response = FALSE;
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE");
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE");
}
else {
/* XXX - what if the direction is unknown? */
is_response = TRUE;
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE");
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE");
}
sdlc_ti = proto_tree_add_item(tree, proto_sdlc, tvb, 0, -1,
ENC_NA);
sdlc_tree = proto_item_add_subtree(sdlc_ti, ett_sdlc);
proto_tree_add_uint(sdlc_tree, hf_sdlc_address, tvb, 0, 1,
addr);
/*
* XXX - SDLC has a mod-128 mode as well as a mod-7 mode.
* We can infer the mode from an SNRM/SRME frame, but if
* we don't see one of them, we may have to have a preference
* to control what to use.
*/
control = dissect_xdlc_control(tvb, 1, pinfo, sdlc_tree, hf_sdlc_control,
ett_sdlc_control, &sdlc_cf_items, NULL, NULL, NULL,
is_response, FALSE, FALSE);
sdlc_header_len += XDLC_CONTROL_LEN(control, FALSE);
proto_item_set_len(sdlc_ti, sdlc_header_len);
/*
* XXX - is there an FCS at the end, at least in Sniffer
* captures? (There doesn't appear to be.)
*/
next_tvb = tvb_new_subset_remaining(tvb, sdlc_header_len);
if (XDLC_IS_INFORMATION(control)) {
/* call the SNA dissector */
call_dissector(sna_handle, next_tvb, pinfo, tree);
} else
call_data_dissector(next_tvb, pinfo, tree);
return tvb_captured_length(tvb);
}
void
proto_register_sdlc(void)
{
static hf_register_info hf[] = {
{ &hf_sdlc_address,
{ "Address Field", "sdlc.address", FT_UINT8, BASE_HEX,
NULL, 0x0, "Address", HFILL }},
{ &hf_sdlc_control,
{ "Control Field", "sdlc.control", FT_UINT16, BASE_HEX,
NULL, 0x0, NULL, HFILL }},
{ &hf_sdlc_n_r,
{ "N(R)", "sdlc.control.n_r", FT_UINT8, BASE_DEC,
NULL, XDLC_N_R_MASK, NULL, HFILL }},
{ &hf_sdlc_n_s,
{ "N(S)", "sdlc.control.n_s", FT_UINT8, BASE_DEC,
NULL, XDLC_N_S_MASK, NULL, HFILL }},
{ &hf_sdlc_p,
{ "Poll", "sdlc.control.p", FT_BOOLEAN, 8,
TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},
{ &hf_sdlc_f,
{ "Final", "sdlc.control.f", FT_BOOLEAN, 8,
TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},
{ &hf_sdlc_s_ftype,
{ "Supervisory frame type", "sdlc.control.s_ftype", FT_UINT8, BASE_HEX,
VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL }},
{ &hf_sdlc_u_modifier_cmd,
{ "Command", "sdlc.control.u_modifier_cmd", FT_UINT8, BASE_HEX,
VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL }},
{ &hf_sdlc_u_modifier_resp,
{ "Response", "sdlc.control.u_modifier_resp", FT_UINT8, BASE_HEX,
VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL }},
{ &hf_sdlc_ftype_i,
{ "Frame type", "sdlc.control.ftype", FT_UINT8, BASE_HEX,
VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL }},
{ &hf_sdlc_ftype_s_u,
{ "Frame type", "sdlc.control.ftype", FT_UINT8, BASE_HEX,
VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }},
};
static gint *ett[] = {
&ett_sdlc,
&ett_sdlc_control,
};
proto_sdlc = proto_register_protocol(
"Synchronous Data Link Control (SDLC)", "SDLC", "sdlc");
proto_register_field_array(proto_sdlc, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_sdlc(void)
{
dissector_handle_t sdlc_handle;
/*
* Get handle for the SNA dissector.
*/
sna_handle = find_dissector_add_dependency("sna", proto_sdlc);
sdlc_handle = create_dissector_handle(dissect_sdlc, proto_sdlc);
dissector_add_uint("wtap_encap", WTAP_ENCAP_SDLC, sdlc_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:
*/
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