forked from osmocom/wireshark
213 lines
5.6 KiB
C
213 lines
5.6 KiB
C
/* packet-sdlc.c
|
|
* Routines for SDLC frame disassembly
|
|
*
|
|
* Wireshark - Network traffic analyzer
|
|
* By Gerald Combs <gerald@wireshark.org>
|
|
* Copyright 1998
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0-or-later
|
|
*/
|
|
|
|
#include "config.h"
|
|
|
|
#include <epan/packet.h>
|
|
#include <wiretap/wtap.h>
|
|
#include <epan/xdlc.h>
|
|
|
|
/*
|
|
* See:
|
|
*
|
|
* http://web.archive.org/web/20020206033700/http://www.wanresources.com/snacell.html
|
|
*
|
|
* http://web.archive.org/web/20150522015710/http://www.protocols.com/pbook/sna.htm
|
|
*
|
|
* Systems Network Architecture Formats, GA27-3136-20:
|
|
* https://publibz.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/D50A5007/CCONTENTS
|
|
*/
|
|
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:
|
|
*/
|