349 lines
9.0 KiB
C
349 lines
9.0 KiB
C
/* packet-llc.c
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* Routines for IEEE 802.2 LLC layer
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* Gilbert Ramirez <gramirez@tivoli.com>
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*
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* $Id: packet-llc.c,v 1.26 1999/10/12 06:20:11 gram Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@unicom.net>
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* Copyright 1998 Gerald Combs
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*
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#ifdef HAVE_SYS_TYPES_H
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# include <sys/types.h>
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#endif
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#include <glib.h>
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#include "packet.h"
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#include "xdlc.h"
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static int proto_llc = -1;
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static int hf_llc_dsap = -1;
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static int hf_llc_ssap = -1;
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static int hf_llc_ctrl = -1;
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static int hf_llc_type = -1;
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static int hf_llc_oui = -1;
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typedef void (capture_func_t)(const u_char *, int, guint32, packet_counts *);
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typedef void (dissect_func_t)(const u_char *, int, frame_data *, proto_tree *);
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/* The SAP info is split into two tables, one value_string table and one table of sap_info. This is
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* so that the value_string can be used in the header field registration.
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*/
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struct sap_info {
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guint8 sap;
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capture_func_t *capture_func;
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dissect_func_t *dissect_func;
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};
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static const value_string sap_vals[] = {
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{ 0x00, "NULL LSAP" },
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{ 0x02, "LLC Sub-Layer Management Individual" },
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{ 0x03, "LLC Sub-Layer Management Group" },
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{ 0x04, "SNA Path Control Individual" },
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{ 0x05, "SNA Path Control Group" },
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{ 0x06, "TCP/IP" },
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{ 0x08, "SNA" },
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{ 0x0C, "SNA" },
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{ 0x42, "Spanning Tree BPDU" },
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{ 0x7F, "ISO 802.2" },
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{ 0x80, "XNS" },
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{ 0xAA, "SNAP" },
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{ 0xBA, "Banyan Vines" },
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{ 0xBC, "Banyan Vines" },
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{ 0xE0, "NetWare" },
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{ 0xF0, "NetBIOS" },
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{ 0xF4, "IBM Net Management Individual" },
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{ 0xF5, "IBM Net Management Group" },
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{ 0xF8, "Remote Program Load" },
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{ 0xFC, "Remote Program Load" },
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{ 0xFE, "ISO Network Layer" },
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{ 0xFF, "Global LSAP" },
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{ 0x00, NULL }
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};
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static struct sap_info saps[] = {
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{ 0x00, NULL, NULL },
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{ 0x02, NULL, NULL },
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{ 0x03, NULL, NULL },
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{ 0x04, NULL, dissect_sna },
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{ 0x05, NULL, NULL },
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{ 0x06, capture_ip, dissect_ip },
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{ 0x08, NULL, NULL },
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{ 0x0C, NULL, NULL },
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{ 0x42, NULL, dissect_bpdu },
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{ 0x7F, NULL, NULL },
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{ 0x80, NULL, NULL },
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{ 0xAA, NULL, NULL },
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{ 0xBA, NULL, NULL },
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{ 0xBC, NULL, NULL },
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{ 0xE0, NULL, dissect_ipx },
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{ 0xF0, capture_netbios, dissect_netbios },
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{ 0xF4, NULL, NULL },
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{ 0xF5, NULL, NULL },
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{ 0xF8, NULL, NULL },
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{ 0xFC, NULL, NULL },
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{ 0xFE, NULL, dissect_osi },
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{ 0xFF, NULL, NULL },
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{ 0x00, NULL, NULL}
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};
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static const value_string llc_ctrl_vals[] = {
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{ 0, "Information Transfer" },
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{ 1, "Supervisory" },
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{ 2, "Unknown" },
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{ 3, "Unnumbered Information" },
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{ 0, NULL }
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};
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static const value_string llc_oui_vals[] = {
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{ 0x000000, "Encapsulated Ethernet" },
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/*
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http://www.cisco.com/univercd/cc/td/doc/product/software/ios113ed/113ed_cr/ibm_r/brprt1/brsrb.htm
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*/
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{ 0x0000f8, "Cisco 90-Compatible" },
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{ 0x0000c0, "Cisco" },
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{ 0x0080c2, "Bridged Frame-Relay" }, /* RFC 2427 */
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{ 0, NULL }
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};
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static capture_func_t *
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sap_capture_func(u_char sap) {
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int i=0;
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/* look for the second record where sap == 0, which should
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* be the last record
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*/
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while (saps[i].sap > 0 || i == 0) {
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if (saps[i].sap == sap) {
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return saps[i].capture_func;
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}
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i++;
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}
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return NULL;
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}
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static dissect_func_t *
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sap_dissect_func(u_char sap) {
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int i=0;
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/* look for the second record where sap == 0, which should
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* be the last record
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*/
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while (saps[i].sap > 0 || i == 0) {
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if (saps[i].sap == sap) {
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return saps[i].dissect_func;
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}
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i++;
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}
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return dissect_data;
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}
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void
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capture_llc(const u_char *pd, int offset, guint32 cap_len, packet_counts *ld) {
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int is_snap;
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guint16 control;
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int control_len;
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guint16 etype;
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capture_func_t *capture;
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is_snap = (pd[offset] == 0xAA) && (pd[offset+1] == 0xAA);
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/*
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* The low-order bit of the SSAP apparently determines whether this
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* is a request or a response. (RFC 1390, "Transmission of IP and
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* ARP over FDDI Networks", says
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*
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* Command frames are identified by having the low order
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* bit of the SSAP address reset to zero. Response frames
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* have the low order bit of the SSAP address set to one.
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*
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* and a page I've seen seems to imply that's part of 802.2.)
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*
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* XXX - that page also implies that LLC Type 2 always uses
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* extended operation, so we don't need to determine whether
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* it's basic or extended operation; is that the case?
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*/
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control = get_xdlc_control(pd, offset+2, pd[offset+1] & 0x01, TRUE);
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control_len = XDLC_CONTROL_LEN(control, TRUE);
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if (is_snap)
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control_len += 5; /* 3 bytes of OUI, 2 bytes of ethertype */
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if (is_snap) {
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if (XDLC_HAS_PAYLOAD(control)) {
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/*
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* This frame has a payload to be analyzed.
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*/
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etype = (pd[offset+6] << 8) | pd[offset+7];
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offset += control_len;
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capture_ethertype(etype, offset, pd, cap_len, ld);
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}
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}
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else {
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if (XDLC_HAS_PAYLOAD(control)) {
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/*
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* This frame has a payload to be analyzed.
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*/
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capture = sap_capture_func(pd[offset]);
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/* non-SNAP */
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offset += control_len;
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if (capture) {
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capture(pd, offset, cap_len, ld);
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}
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else {
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ld->other++;
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}
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}
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}
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}
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void
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dissect_llc(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
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proto_tree *llc_tree = NULL;
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proto_item *ti = NULL;
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int is_snap;
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guint16 control;
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int control_len;
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guint16 etype;
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dissect_func_t *dissect;
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is_snap = (pd[offset] == 0xAA) && (pd[offset+1] == 0xAA);
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if (check_col(fd, COL_PROTOCOL)) {
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col_add_str(fd, COL_PROTOCOL, "LLC");
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}
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if (tree) {
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ti = proto_tree_add_item(tree, proto_llc, offset, 0, NULL);
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llc_tree = proto_item_add_subtree(ti, ETT_LLC);
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proto_tree_add_item(llc_tree, hf_llc_dsap, offset, 1, pd[offset]);
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proto_tree_add_item(llc_tree, hf_llc_ssap, offset+1, 1, pd[offset+1]);
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} else
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llc_tree = NULL;
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/*
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* The low-order bit of the SSAP apparently determines whether this
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* is a request or a response. (RFC 1390, "Transmission of IP and
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* ARP over FDDI Networks", says
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*
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* Command frames are identified by having the low order
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* bit of the SSAP address reset to zero. Response frames
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* have the low order bit of the SSAP address set to one.
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*
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* and a page I've seen seems to imply that's part of 802.2.)
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*
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* XXX - that page also implies that LLC Type 2 always uses
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* extended operation, so we don't need to determine whether
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* it's basic or extended operation; is that the case?
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*/
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control = dissect_xdlc_control(pd, offset+2, fd, llc_tree,
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hf_llc_ctrl, pd[offset+1] & 0x01, TRUE);
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control_len = XDLC_CONTROL_LEN(control, TRUE);
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if (is_snap)
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control_len += 5; /* 3 bytes of OUI, 2 bytes of ethertype */
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if (tree)
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proto_item_set_len(ti, control_len);
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/*
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* XXX - do we want to append the SAP information to the stuff
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* "dissect_xdlc_control()" put in the COL_INFO column, rather
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* than overwriting it?
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*/
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if (is_snap) {
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if (check_col(fd, COL_INFO)) {
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col_add_str(fd, COL_INFO, "802.2 LLC (SNAP)");
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}
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if (tree) {
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proto_tree_add_item(llc_tree, hf_llc_oui, offset+3, 3,
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pd[offset+3] << 16 | pd[offset+4] << 8 | pd[offset+5]);
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}
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if (XDLC_HAS_PAYLOAD(control)) {
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/*
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* This frame has a payload to be analyzed.
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*/
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etype = pntohs(&pd[offset+6]);
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offset += control_len;
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/* w/o even checking, assume OUI is ethertype */
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ethertype(etype, offset, pd, fd, tree, llc_tree,
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hf_llc_type);
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}
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}
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else {
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if (check_col(fd, COL_INFO)) {
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col_add_fstr(fd, COL_INFO, "802.2 LLC (%s)",
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val_to_str(pd[offset], sap_vals, "%02x"));
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}
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if (XDLC_HAS_PAYLOAD(control)) {
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/*
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* This frame has a payload to be analyzed.
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*/
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dissect = sap_dissect_func(pd[offset]);
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/* non-SNAP */
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offset += control_len;
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if (dissect) {
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dissect(pd, offset, fd, tree);
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}
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else {
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dissect_data(pd, offset, fd, tree);
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}
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}
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}
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}
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void
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proto_register_llc(void)
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{
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static hf_register_info hf[] = {
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{ &hf_llc_dsap,
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{ "DSAP", "llc.dsap", FT_UINT8, BASE_HEX, VALS(sap_vals), 0x0,
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"" }},
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{ &hf_llc_ssap,
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{ "SSAP", "llc.ssap", FT_UINT8, BASE_HEX, VALS(sap_vals), 0x0,
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"" }},
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{ &hf_llc_ctrl,
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{ "Control", "llc.control", FT_UINT8, BASE_HEX, VALS(llc_ctrl_vals), 0x0,
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"" }},
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/* registered here but handled in ethertype.c */
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{ &hf_llc_type,
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{ "Type", "llc.type", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0,
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"" }},
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{ &hf_llc_oui,
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{ "Organization Code", "llc.oui", FT_UINT24, BASE_HEX, VALS(llc_oui_vals), 0x0,
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""}}
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};
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proto_llc = proto_register_protocol ("Logical-Link Control", "llc" );
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proto_register_field_array(proto_llc, hf, array_length(hf));
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}
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