wireshark/packet-gprs-llc.c

395 lines
14 KiB
C

/* packet-llcgprs.c
* Routines for Logical Link Control GPRS dissection ETSI 4.64
* Copyright 2000, Josef Korelus <jkor@quick.cz>
*
* $Id: packet-gprs-llc.c,v 1.3 2004/04/13 21:32:57 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
* Copyright 1998 Gerald Combs
*
* Copied from WHATEVER_FILE_YOU_USED (where "WHATEVER_FILE_YOU_USED"
* is a dissector file; if you just copied this from README.developer,
* don't bother with the "Copied from" - you don't even need to put
* in a "Copied from" if you copied an existing dissector, especially
* if the bulk of the code in the new dissector is your code)
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#ifdef NEED_SNPRINTF_H
# include "snprintf.h"
#endif
#include <epan/packet.h>
/*
#include "packet-llcgprs.h"
*/
#define I_FORMAT 1
#define S_FORMAT 2
#define UI_FORMAT 3
#define U_FORMAT 4
#define I_SACK 5
#define S_SACK 6
#define UI_MASK_FMT 0xe000
#define UI_MASK_SPB 0x1800
#define UI_MASK_NU 0x07fc
#define UI_MASK_E 0x0002
#define UI_MASK_PM 0x0001
/* Initialize the protocol and registered fields */
static int proto_llcgprs = -1;
static int hf_llcgprs_pd = -1;
static int hf_llcgprs_cr = -1;
static int hf_llcgprs_sapi = -1;
static int hf_llcgprs_sapib = -1;
static int hf_llcgprs_U_fmt = -1;/* 3 upper bits in controlfield (UI format) */
static int hf_llcgprs_sp_bits = -1; /*Spare bits in control field*/
static int hf_llcgprs_NU = -1; /*Transmited unconfirmed sequence number*/
static int hf_llcgprs_E_bit = -1;/* Encryption mode bit*/
static int hf_llcgprs_PM_bit = -1;
static int hf_llcgprs_Un = -1;
static int hf_llcgprs_As = -1;
static int hf_llcgprs_ucom = -1;
static int hf_llcgprs_PF = -1;
static int hf_llcgprs_S_fmt = -1;
static int hf_llcgprs_NR = -1;
static int hf_llcgprs_sjsd = -1;
/*static int hf_llcgprs_pd = -1;
*/
/* Initialize the subtree pointers */
static gint ett_llcgprs = -1;
static gint ett_llcgprs_adf = -1;
static gint ett_llcgprs_ctrlf = -1;
static gint ett_ui = -1;
static gint ett_llcgprs_sframe = -1;
static dissector_handle_t data_handle;
static dissector_table_t llcgprs_subdissector_table;
static const value_string sapi_t[] = {
{ 0, "Reserved"},
{ 1, "GPRS Mobility Management" },
{ 2, "Tunnelling of messages 2" },
{ 3, "User data 3"},
{ 4, "Reserved" },
{ 5, "User data 5" },
{ 6, "Reserved" },
{ 7, "SMS" },
{ 8, "Tunneling of messages 8" },
{ 9, "User data 9" },
{ 10, "Reserved" },
{ 11, "User data 11" },
{ 12, "Reserved" },
{ 13, "Reserved" },
{ 14, "Reserved" },
{ 15, "Reserved" },
{ 0, NULL },
};
static const value_string sapi_abrv[] = {
{ 0, "0"},
{ 1, "LLGMM" },
{ 2, "TOM2" },
{ 3, "LL3"},
{ 4, "4" },
{ 5, "LL5" },
{ 6, "6" },
{ 7, "LLSMS" },
{ 8, "TOM8" },
{ 9, "LL9" },
{ 10, "10" },
{ 11, "LL11" },
{ 12, "12" },
{ 13, "13" },
{ 14, "14" },
{ 15, "15" },
{ 0, NULL },
};
static const true_false_string a_bit = {
"To solicit an acknowledgement from the peer LLE. ",
"The peer LLE is not requested to send an acknowledgment."
};
static const true_false_string pd_bit = {
"Invalid frame PD=1",
"OK"
};
static const true_false_string e_bit = {
" encrypted frame",
" non encrypted frame"
};
static const true_false_string pm_bit = {
"FCS covers the frame header and informations fields",
"FCS covers only the frame header and first N202 octets of the information fileld"
};
static const true_false_string cr_bit = {
"DownLink/UpLink = Command/Response",
"DownLink/UpLink = Response/Command"
};
/* bits are swaped comparing with "Table 3" in ETSI document*/
static const value_string pme[] = {
{ 0, "unprotected,non-ciphered information" },
{ 1, "protected, non-ciphered information" },
{ 2, "unprotected,ciphered information"},
{ 3, "protected, ciphered information" },
{ 0, NULL},
};
static const value_string cr_formats_unnumb[]= {
{ 0x1, "DM-response" },
{ 0x4, "DISC-command" },
{ 0x6, "UA-response" },
{ 0x7, "SABM" },
{ 0x8, "FRMR" },
{ 0xb, "XID" },
{ 0, NULL },
};
static const value_string cr_formats_ipluss[] = {
{ 0x0,"RR" },
{ 0x1,"ACK" },
{ 0x2,"RNR" },
{ 0x3,"SACK" },
{ 0, NULL },
};
/* Code to actually dissect the packets */
static void
dissect_llcgprs(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
guint8 addr_fld=0, sapi=0, ctrl_fld_fb=0, frame_format, tmp=0 ;
guint16 offset=0 , epm = 0, nu=0,ctrl_fld_ui_s=0,crc_start=0 ;
proto_item *ti, *addres_field_item, *ctrl_field_item, *ui_ti;
proto_tree *llcgprs_tree=NULL , *ad_f_tree =NULL, *ctrl_f_tree=NULL, *ui_tree=NULL;
tvbuff_t *next_tvb;
/* Make entries in Protocol column and Info column on summary display */
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "GPRS-LLC");
crc_start = tvb_length(tvb)-3;
addr_fld = tvb_get_guint8(tvb,offset);
offset++;
if (addr_fld > 128 ) {
if (check_col(pinfo->cinfo,COL_INFO))
col_add_str(pinfo->cinfo,COL_INFO,"Invalid packet - Protocol Discriminator bit is set to 1");
return;
}
sapi = addr_fld & 0xF;
if (check_col(pinfo->cinfo, COL_INFO))
col_add_fstr(pinfo->cinfo, COL_INFO, "SAPI: %s,", match_strval(sapi,sapi_abrv));
/* In the interest of speed, if "tree" is NULL, don't do any work not
necessary to generate protocol tree items. */
if (tree) {
ti = proto_tree_add_protocol_format(tree, proto_llcgprs, tvb, 0, -1,"MS-SGSN LLC (Mobile Station - Serving GPRS Support Node Logical Link Control) SAPI: %s, ", match_strval(sapi,sapi_t));
llcgprs_tree = proto_item_add_subtree(ti, ett_llcgprs);
/* add an item to the subtree, see section 1.6 for more information */
proto_tree_add_text( llcgprs_tree, tvb, crc_start,3, "CRC of LLC layer" );
addres_field_item = proto_tree_add_uint_format(llcgprs_tree,hf_llcgprs_sapi,
tvb, 0,1, sapi, "Address field SAPI: %d, ", sapi );
ad_f_tree = proto_item_add_subtree(addres_field_item, ett_llcgprs_adf);
proto_tree_add_boolean(ad_f_tree, hf_llcgprs_pd, tvb,0,1, addr_fld );
proto_tree_add_boolean(ad_f_tree, hf_llcgprs_cr, tvb,0,1, addr_fld );
proto_tree_add_uint(ad_f_tree, hf_llcgprs_sapib, tvb, 0, 1, addr_fld );
}
ctrl_fld_fb = tvb_get_guint8(tvb,offset);
if ( ctrl_fld_fb < 0xc0 ){
frame_format = ( ctrl_fld_fb < 0x80)? I_FORMAT : S_FORMAT;
}
else {
frame_format = ( ctrl_fld_fb < 0xe0 )? UI_FORMAT : U_FORMAT;
}
switch (frame_format){
case I_FORMAT:
if (check_col(pinfo->cinfo,COL_INFO)){
col_append_str(pinfo->cinfo,COL_INFO, "I, ");
}
break;
case S_FORMAT:
case UI_FORMAT:
nu = ctrl_fld_ui_s = tvb_get_ntohs(tvb, offset);
offset +=2;
epm = ctrl_fld_ui_s & 0x3;
nu = (nu >>2)&0x01FF;
if (frame_format == S_FORMAT){
if (check_col(pinfo->cinfo, COL_INFO)){
col_append_str(pinfo->cinfo, COL_INFO, "S, ");
col_append_str(pinfo->cinfo, COL_INFO, match_strval(epm,cr_formats_ipluss));
col_append_fstr(pinfo->cinfo, COL_INFO, ", N(R) = %u, ", nu);
}
if (tree){
ctrl_field_item = proto_tree_add_text(llcgprs_tree, tvb, offset-2,2,"Supervisory format: %s: N(R) = %u",match_strval(epm,cr_formats_ipluss), nu);
ctrl_f_tree = proto_item_add_subtree( ctrl_field_item, ett_llcgprs_sframe);
proto_tree_add_uint( ctrl_f_tree, hf_llcgprs_S_fmt, tvb, offset-2,2, ctrl_fld_ui_s );
proto_tree_add_boolean( ctrl_f_tree, hf_llcgprs_As, tvb, offset-2, 2, ctrl_fld_ui_s );
proto_tree_add_uint(ctrl_f_tree, hf_llcgprs_NR, tvb, offset-2, 2, ctrl_fld_ui_s );
proto_tree_add_uint(ctrl_f_tree, hf_llcgprs_sjsd, tvb, offset-2, 2, ctrl_fld_ui_s );
}
}else{
/*UI format*/
if (check_col(pinfo->cinfo, COL_INFO)) {
col_append_str(pinfo->cinfo, COL_INFO, " UI, ");
col_append_str(pinfo->cinfo, COL_INFO, match_strval(epm, pme ));
col_append_fstr(pinfo->cinfo,COL_INFO, ", N(U) = %u, ", nu);
}
if (tree){
ctrl_field_item = proto_tree_add_text(llcgprs_tree, tvb, offset-2, 2, "Unnumbered Information format - UI, N(U) = %u", nu);
ctrl_f_tree = proto_item_add_subtree(ctrl_field_item, ett_llcgprs_ctrlf);
proto_tree_add_uint( ctrl_f_tree, hf_llcgprs_U_fmt, tvb, offset-2, 2, ctrl_fld_ui_s);
proto_tree_add_uint( ctrl_f_tree, hf_llcgprs_sp_bits, tvb, offset-2,2,ctrl_fld_ui_s);
proto_tree_add_uint( ctrl_f_tree, hf_llcgprs_NU, tvb, offset-2, 2, ctrl_fld_ui_s);
proto_tree_add_boolean( ctrl_f_tree, hf_llcgprs_E_bit, tvb, offset-2,2,ctrl_fld_ui_s);
proto_tree_add_boolean( ctrl_f_tree, hf_llcgprs_PM_bit, tvb, offset-2,2,ctrl_fld_ui_s);
}
next_tvb = tvb_new_subset(tvb, offset,crc_start-3, -1 );
if (epm < 2){
if (!dissector_try_port(llcgprs_subdissector_table,sapi, next_tvb, pinfo, tree))
call_dissector(data_handle, next_tvb, pinfo, tree);
}
else call_dissector(data_handle, next_tvb, pinfo, tree);
}
break;
case U_FORMAT:
offset +=1;
tmp = 0;
tmp = ctrl_fld_fb & 0xf;
if (check_col(pinfo->cinfo, COL_INFO)) {
col_append_str(pinfo->cinfo, COL_INFO, " U, ");
col_append_str(pinfo->cinfo, COL_INFO, match_strval(tmp, cr_formats_unnumb));
}
if(tree){
ui_ti = proto_tree_add_text(llcgprs_tree,tvb,offset-1,crc_start-1,"Unnumbered frame: %s", match_strval(tmp,cr_formats_unnumb));
ui_tree = proto_item_add_subtree( ui_ti, ett_ui);
proto_tree_add_uint( ui_tree, hf_llcgprs_Un, tvb, offset-1, 1, ctrl_fld_fb);
proto_tree_add_boolean( ui_tree, hf_llcgprs_PF, tvb, offset-1, 1, ctrl_fld_fb);
proto_tree_add_uint( ui_tree, hf_llcgprs_ucom, tvb, offset-1, 1, ctrl_fld_fb);
}
break;
/* case I_SACK:
break;
case S_SACK:
break;
*/
}
/* proto_tree_add_item(llcgprs_tree,
hf_llcgprs_FIELDABBREV, tvb, offset, len, FALSE)
*/
/* Continue adding tree items to process the packet here */
/* If this protocol has a sub-dissector call it here, see section 1.8 */
}
/* Register the protocol with Ethereal */
/* this format is require because a script is used to build the C function
that calls all the protocol registration.
*/
void
proto_register_llcgprs(void)
{
/* Setup list of header fields See Section 1.6.1 for details*/
static hf_register_info hf[] = {
{ &hf_llcgprs_sapi,
{ "SAPI", "llcgprs.sapi", FT_UINT8, BASE_DEC, VALS(sapi_abrv), 0x0,"Service Access Point Identifier", HFILL }},
{ &hf_llcgprs_pd,
{ "Protocol Discriminator_bit", "llcgprs.pd", FT_BOOLEAN,8, TFS(&pd_bit), 0x80, " Protocol Discriminator bit (should be 0)", HFILL }},
{&hf_llcgprs_sjsd,
{ "Supervisory function bits","llcgprs.s1s2", FT_UINT16, BASE_HEX, VALS(cr_formats_ipluss),0x3, "Supervisory functions bits",HFILL }},
{ &hf_llcgprs_cr,
{ "Command/Response bit", "llcgprs.cr", FT_BOOLEAN, 8, TFS(&cr_bit), 0x40, " Command/Response bit", HFILL}},
{ &hf_llcgprs_sapib,
{ "SAPI", "llcgprs.sapib", FT_UINT8, BASE_DEC , VALS(sapi_t), 0xf, "Service Access Point Identifier ",HFILL }},
{ &hf_llcgprs_U_fmt,
{ "UI format", "llcgprs.ui", FT_UINT16, BASE_HEX, NULL, UI_MASK_FMT, "UI frame format",HFILL}},
{ &hf_llcgprs_Un,
{ "U format", "llcgprs.u", FT_UINT8, BASE_DEC, NULL, 0xe0, " U frame format", HFILL}},
{ &hf_llcgprs_sp_bits,
{ "Spare bits", "llcgprs.ui_sp_bit", FT_UINT16, BASE_HEX, NULL, UI_MASK_SPB, "Spare bits", HFILL}},
{ &hf_llcgprs_NU,
{ "N(U)", "llcgprs.nu", FT_UINT16, BASE_DEC, NULL, UI_MASK_NU, "Transmited unconfirmed sequence number", HFILL}},
{ &hf_llcgprs_E_bit,
{ "E bit", "llcgprs.e", FT_BOOLEAN, 16, TFS(&e_bit), UI_MASK_E,"Encryption mode bit",HFILL }},
{ &hf_llcgprs_PM_bit,
{ "PM bit", "llcgprs.pm", FT_BOOLEAN, 16, TFS(&pm_bit), UI_MASK_PM, "Protected mode bit",HFILL}},
{ &hf_llcgprs_As,
{ "Ackn request bit", "llcgprs.as", FT_BOOLEAN, 16, TFS(&a_bit), 0x2000 ,"Acknowledgement request bit A", HFILL}},
{ &hf_llcgprs_PF,
{ "P/F bit", "llcgprs.pf", FT_BOOLEAN, 8, NULL, 0x10,"Poll /Finall bit", HFILL}},
{ &hf_llcgprs_ucom,
{ "Command/Response","llcgprs.ucom", FT_UINT8, BASE_HEX, VALS(cr_formats_unnumb),0xf,"Commands and Responses",HFILL }},
{ &hf_llcgprs_NR,
{ "Receive sequence number", "llcgprs.nr",FT_UINT16, BASE_DEC, NULL, UI_MASK_NU,"Receive sequence number N(R)",HFILL }},
{&hf_llcgprs_S_fmt,
{ "S format", "llcgprs.s", FT_UINT16, BASE_DEC, NULL, 0xc000,"Supervisory format S", HFILL}}
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_llcgprs,
&ett_llcgprs_adf,
&ett_llcgprs_ctrlf,
&ett_ui,
&ett_llcgprs_sframe,
};
/* Register the protocol name and description */
proto_llcgprs = proto_register_protocol("Logical Link Control GPRS",
"GPRS-LLC", "llcgprs");
llcgprs_subdissector_table = register_dissector_table("llcgprs.sapi","GPRS LLC SAPI", FT_UINT8,BASE_HEX);
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_llcgprs, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
register_dissector( "llcgprs", dissect_llcgprs, proto_llcgprs);
}
/* If this dissector uses sub-dissector registration add a registration routine.
This format is required because a script is used to find these routines and
create the code that calls these routines.
*/
void
proto_reg_handoff_llcgprs(void)
{
dissector_handle_t llcgprs_handle;
llcgprs_handle = create_dissector_handle(dissect_llcgprs,
proto_llcgprs);
/* dissector_add("PARENT_SUBFIELD", ID_VALUE, llcgprs_handle);
*/
data_handle = find_dissector("data");
}