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wireshark/packet-llc.c

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/* packet-llc.c
* Routines for IEEE 802.2 LLC layer
* Gilbert Ramirez <gram@xiexie.org>
*
* $Id: packet-llc.c,v 1.71 2000/11/19 08:53:59 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#include <glib.h>
#include "packet.h"
#include "oui.h"
#include "xdlc.h"
#include "etypes.h"
#include "llcsaps.h"
#include "packet-cdp.h"
#include "packet-cgmp.h"
#include "packet-ip.h"
#include "packet-ipx.h"
#include "packet-netbios.h"
#include "packet-osi.h"
#include "packet-sna.h"
#include "packet-vtp.h"
static int proto_llc = -1;
static int hf_llc_dsap = -1;
static int hf_llc_ssap = -1;
static int hf_llc_dsap_ig = -1;
static int hf_llc_ssap_cr = -1;
static int hf_llc_ctrl = -1;
static int hf_llc_type = -1;
static int hf_llc_oui = -1;
static int hf_llc_pid = -1;
static gint ett_llc = -1;
static gint ett_llc_ctrl = -1;
static dissector_table_t subdissector_table;
static dissector_handle_t bpdu_handle;
typedef void (capture_func_t)(const u_char *, int, packet_counts *);
/* The SAP info is split into two tables, one value_string table and one
* table of sap_info. This is so that the value_string can be used in the
* header field registration.
*/
struct sap_info {
guint8 sap;
capture_func_t *capture_func;
};
/*
* Group/Individual bit, in the DSAP.
*/
#define DSAP_GI_BIT 0x01
/*
* Command/Response bit, in the SSAP.
*
* The low-order bit of the SSAP apparently determines whether this
* is a request or a response. (RFC 1390, "Transmission of IP and
* ARP over FDDI Networks", says
*
* Command frames are identified by having the low order
* bit of the SSAP address reset to zero. Response frames
* have the low order bit of the SSAP address set to one.
*
* and a page I've seen seems to imply that's part of 802.2.)
*/
#define SSAP_CR_BIT 0x01
/*
* Mask to extrace the SAP number from the DSAP or the SSAP.
*/
#define SAP_MASK 0xFE
/*
* These are for SSAP and DSAP, wth last bit always zero.
* XXX - some DSAPs come in separate "individual" and "group" versions,
* with the last bit 0 and 1, respectively (e.g., LLC Sub-layer Management,
* IBM SNA Path Control, IBM Net Management), but, whilst 0xFE is
* the ISO Network Layer Protocol, 0xFF is the Global LSAP.
*/
static const value_string sap_vals[] = {
{ SAP_NULL, "NULL LSAP" },
{ SAP_LLC_SLMGMT, "LLC Sub-Layer Management" },
{ SAP_SNA_PATHCTRL, "SNA Path Control" },
{ SAP_IP, "TCP/IP" },
{ SAP_SNA1, "SNA" },
{ SAP_SNA2, "SNA" },
{ SAP_PROWAY_NM_INIT, "PROWAY (IEC955) Network Management and Initialization" },
{ SAP_TI, "Texas Instruments" },
{ SAP_BPDU, "Spanning Tree BPDU" },
{ SAP_RS511, "EIA RS-511 Manufacturing Message Service" },
#if 0
/* XXX - setting the group bit makes this 0x7F; is that just
a group version of this? */
{ 0x7E, "ISO 8208 (X.25 over 802.2 Type 2)" },
#endif
{ 0x7F, "ISO 802.2" },
{ SAP_XNS, "XNS" },
{ SAP_NESTAR, "Nestar" },
{ SAP_PROWAY_ASLM, "PROWAY (IEC955) Active Station List Maintenance" },
{ SAP_ARP, "ARP" }, /* XXX - hand to "dissect_arp()"? */
{ SAP_SNAP, "SNAP" },
{ SAP_VINES1, "Banyan Vines" },
{ SAP_VINES2, "Banyan Vines" },
{ SAP_NETWARE, "NetWare" },
{ SAP_NETBIOS, "NetBIOS" },
{ SAP_IBMNM, "IBM Net Management" },
{ SAP_RPL1, "Remote Program Load" },
{ SAP_UB, "Ungermann-Bass" },
{ SAP_RPL2, "Remote Program Load" },
{ SAP_OSINL, "ISO Network Layer" },
{ SAP_GLOBAL, "Global LSAP" },
{ 0x00, NULL }
};
static struct sap_info saps[] = {
{ SAP_IP, capture_ip },
{ SAP_NETWARE, capture_ipx },
{ SAP_NETBIOS, capture_netbios },
{ 0x00, NULL}
};
/*
* See
*
* http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/vlan.htm
*
* for the PIDs for VTP and DRiP that go with an OUI of OUI_CISCO.
*/
const value_string oui_vals[] = {
{ OUI_ENCAP_ETHER, "Encapsulated Ethernet" },
/*
http://www.cisco.com/univercd/cc/td/doc/product/software/ios113ed/113ed_cr/ibm_r/brprt1/brsrb.htm
*/
{ OUI_CISCO, "Cisco" },
{ OUI_CISCO_90, "Cisco IOS 9.0 Compatible" },
{ OUI_BFR, "Bridged Frame-Relay" }, /* RFC 2427 */
{ OUI_ATM_FORUM, "ATM Forum" },
{ OUI_APPLE_ATALK, "Apple (AppleTalk)" },
{ OUI_CABLE_BPDU, "DOCSIS Spanning Tree" }, /* DOCSIS spanning tree BPDU */
{ 0, NULL }
};
static capture_func_t *
sap_capture_func(u_char sap) {
int i=0;
/* look for the second record where sap == 0, which should
* be the last record
*/
while (saps[i].sap > 0 || i == 0) {
if (saps[i].sap == sap) {
return saps[i].capture_func;
}
i++;
}
return NULL;
}
void
capture_llc(const u_char *pd, int offset, packet_counts *ld) {
int is_snap;
guint16 control;
int llc_header_len;
guint32 oui;
guint16 etype;
capture_func_t *capture;
if (!BYTES_ARE_IN_FRAME(offset, 2)) {
ld->other++;
return;
}
is_snap = (pd[offset] == SAP_SNAP) && (pd[offset+1] == SAP_SNAP);
llc_header_len = 2; /* DSAP + SSAP */
/*
* XXX - the page referred to in the comment above about the
* Command/Response bit also implies that LLC Type 2 always
* uses extended operation, so we don't need to determine
* whether it's basic or extended operation; is that the case?
*/
control = get_xdlc_control(pd, offset+2, pd[offset+1] & SSAP_CR_BIT,
TRUE);
llc_header_len += XDLC_CONTROL_LEN(control, TRUE);
if (is_snap)
llc_header_len += 5; /* 3 bytes of OUI, 2 bytes of protocol ID */
if (!BYTES_ARE_IN_FRAME(offset, llc_header_len)) {
ld->other++;
return;
}
if (is_snap) {
oui = pd[offset+3] << 16 | pd[offset+4] << 8 | pd[offset+5];
if (XDLC_IS_INFORMATION(control)) {
etype = pntohs(&pd[offset+6]);
switch (oui) {
case OUI_ENCAP_ETHER:
case OUI_APPLE_ATALK:
/* No, I have no idea why Apple used
one of their own OUIs, rather than
OUI_ENCAP_ETHER, and an Ethernet
packet type as protocol ID, for
AppleTalk data packets - but used
OUI_ENCAP_ETHER and an Ethernet
packet type for AARP packets. */
capture_ethertype(etype, offset+8, pd,
ld);
break;
case OUI_CISCO:
capture_ethertype(etype,
offset + 8, pd, ld);
break;
default:
ld->other++;
break;
}
}
}
else {
if (XDLC_IS_INFORMATION(control)) {
capture = sap_capture_func(pd[offset]);
/* non-SNAP */
offset += llc_header_len;
if (capture) {
capture(pd, offset, ld);
}
else {
ld->other++;
}
}
}
}
void
dissect_llc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_tree *llc_tree = NULL;
proto_item *ti = NULL;
int is_snap;
guint16 control;
int llc_header_len;
guint32 oui;
guint16 etype;
guint8 dsap, ssap;
tvbuff_t *next_tvb;
const guint8 *pd;
int offset;
CHECK_DISPLAY_AS_DATA(proto_llc, tvb, pinfo, tree);
pinfo->current_proto = "LLC";
if (check_col(pinfo->fd, COL_PROTOCOL)) {
col_set_str(pinfo->fd, COL_PROTOCOL, "LLC");
}
dsap = tvb_get_guint8(tvb, 0);
if (tree) {
ti = proto_tree_add_item(tree, proto_llc, tvb, 0, 0, FALSE);
llc_tree = proto_item_add_subtree(ti, ett_llc);
proto_tree_add_uint(llc_tree, hf_llc_dsap, tvb, 0,
1, dsap & SAP_MASK);
proto_tree_add_boolean(llc_tree, hf_llc_dsap_ig, tvb, 0,
1, dsap & DSAP_GI_BIT);
} else
llc_tree = NULL;
ssap = tvb_get_guint8(tvb, 1);
if (tree) {
proto_tree_add_uint(llc_tree, hf_llc_ssap, tvb, 1,
1, ssap & SAP_MASK);
proto_tree_add_boolean(llc_tree, hf_llc_ssap_cr, tvb, 1,
1, ssap & SSAP_CR_BIT);
} else
llc_tree = NULL;
is_snap = (dsap == SAP_SNAP) && (ssap == SAP_SNAP);
llc_header_len = 2; /* DSAP + SSAP */
/*
* XXX - the page referred to in the comment above about the
* Command/Response bit also implies that LLC Type 2 always
* uses extended operation, so we don't need to determine
* whether it's basic or extended operation; is that the case?
*/
control = dissect_xdlc_control(tvb, 2, pinfo, llc_tree,
hf_llc_ctrl, ett_llc_ctrl,
ssap & SSAP_CR_BIT, TRUE);
llc_header_len += XDLC_CONTROL_LEN(control, TRUE);
if (is_snap)
llc_header_len += 5; /* 3 bytes of OUI, 2 bytes of protocol ID */
if (tree)
proto_item_set_len(ti, llc_header_len);
if (is_snap) {
oui = tvb_get_ntoh24(tvb, 3);
etype = tvb_get_ntohs(tvb, 6);
if (check_col(pinfo->fd, COL_INFO)) {
col_append_fstr(pinfo->fd, COL_INFO, "; SNAP, OUI 0x%06X (%s), PID 0x%04X",
oui, val_to_str(oui, oui_vals, "Unknown"),
etype);
}
if (tree) {
proto_tree_add_uint(llc_tree, hf_llc_oui, tvb, 3, 3,
oui);
}
next_tvb = tvb_new_subset(tvb, 8, -1, -1);
tvb_compat(next_tvb, &pd, &offset);
switch (oui) {
case OUI_ENCAP_ETHER:
case OUI_APPLE_ATALK:
/* No, I have no idea why Apple used
one of their own OUIs, rather than
OUI_ENCAP_ETHER, and an Ethernet
packet type as protocol ID, for
AppleTalk data packets - but used
OUI_ENCAP_ETHER and an Ethernet
packet type for AARP packets. */
if (XDLC_IS_INFORMATION(control)) {
ethertype(etype, tvb, 8,
pinfo, tree, llc_tree, hf_llc_type);
} else
dissect_data(next_tvb, 0, pinfo, tree);
break;
case OUI_CISCO:
/* So are all CDP packets LLC packets
with an OUI of OUI_CISCO and a
protocol ID of 0x2000, or
are some of them raw or encapsulated
Ethernet? */
if (tree) {
proto_tree_add_uint(llc_tree,
hf_llc_pid, tvb, 6, 2, etype);
}
if (XDLC_IS_INFORMATION(control)) {
switch (etype) {
#if 0
case 0x0102:
dissect_drip(pd, offset, pinfo->fd, tree);
break;
#endif
case 0x2000:
dissect_cdp(pd, offset, pinfo->fd, tree);
break;
case 0x2001:
dissect_cgmp(pd, offset, pinfo->fd, tree);
break;
case 0x2003:
dissect_vtp(pd, offset, pinfo->fd, tree);
break;
default:
dissect_data(next_tvb, 0, pinfo, tree);
break;
}
} else
dissect_data(next_tvb, 0, pinfo, tree);
break;
case OUI_CABLE_BPDU: /* DOCSIS cable modem spanning tree BPDU */
if (tree) {
proto_tree_add_uint(llc_tree,
hf_llc_pid, tvb, 6, 2, etype);
}
call_dissector(bpdu_handle, next_tvb, pinfo, tree);
break;
default:
if (tree) {
proto_tree_add_uint(llc_tree,
hf_llc_pid, tvb, 6, 2, etype);
}
dissect_data(next_tvb, 0, pinfo, tree);
break;
}
}
else {
if (check_col(pinfo->fd, COL_INFO)) {
col_append_fstr(pinfo->fd, COL_INFO,
"; DSAP %s %s, SSAP %s %s",
val_to_str(dsap & SAP_MASK, sap_vals, "%02x"),
dsap & DSAP_GI_BIT ?
"Group" : "Individual",
val_to_str(ssap & SAP_MASK, sap_vals, "%02x"),
ssap & SSAP_CR_BIT ?
"Response" : "Command"
);
}
next_tvb = tvb_new_subset(tvb, llc_header_len, -1, -1);
if (XDLC_IS_INFORMATION(control)) {
/* non-SNAP */
/* do lookup with the subdissector table */
if (!dissector_try_port(subdissector_table, dsap,
next_tvb, pinfo, tree)) {
dissect_data(next_tvb, 0, pinfo, tree);
}
} else {
dissect_data(next_tvb, 0, pinfo, tree);
}
}
}
void
proto_register_llc(void)
{
static struct true_false_string ig_bit = { "Group", "Individual" };
static struct true_false_string cr_bit = { "Response", "Command" };
static hf_register_info hf[] = {
{ &hf_llc_dsap,
{ "DSAP", "llc.dsap", FT_UINT8, BASE_HEX,
VALS(sap_vals), 0x0, "" }},
{ &hf_llc_dsap_ig,
{ "IG Bit", "llc.dsap.ig", FT_BOOLEAN, BASE_HEX,
&ig_bit, 0x0, "Individual/Group" }},
{ &hf_llc_ssap,
{ "SSAP", "llc.ssap", FT_UINT8, BASE_HEX,
VALS(sap_vals), 0x0, "" }},
{ &hf_llc_ssap_cr,
{ "CR Bit", "llc.ssap.cr", FT_BOOLEAN, BASE_HEX,
&cr_bit, 0x0, "Command/Response" }},
{ &hf_llc_ctrl,
{ "Control", "llc.control", FT_UINT16, BASE_HEX,
NULL, 0x0, "" }},
/* registered here but handled in ethertype.c */
{ &hf_llc_type,
{ "Type", "llc.type", FT_UINT16, BASE_HEX,
VALS(etype_vals), 0x0, "" }},
{ &hf_llc_oui,
{ "Organization Code", "llc.oui", FT_UINT24, BASE_HEX,
VALS(oui_vals), 0x0, ""}},
{ &hf_llc_pid,
{ "Protocol ID", "llc.pid", FT_UINT16, BASE_HEX,
NULL, 0x0, ""}}
};
static gint *ett[] = {
&ett_llc,
&ett_llc_ctrl,
};
proto_llc = proto_register_protocol ("Logical-Link Control", "llc" );
proto_register_field_array(proto_llc, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* subdissector code */
subdissector_table = register_dissector_table("llc.dsap");
}
void
proto_reg_handoff_llc(void)
{
/*
* Get a handle for the BPDU dissector.
*/
bpdu_handle = find_dissector("bpdu");
}
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