osmith/wireshark
1
0
Fork 0
forked from osmocom/wireshark
Code Pull requests Releases Wiki Activity
wireshark/packet-llc.c
Guy Harris d9718a693d Remove some more "CHECK_DISPLAY_AS_DATA()" calls and code to set 
"pinfo->current_proto", in dissectors always called through dissector
tables and handles.

Make the IEEE 802.11 dissector static, as it's not called externally.

Clear the Info column in the Linux cooked capture and 802.1q VLAN
dissectors, before extracting anything from the packet, so that if an
exception is thrown, the Info column doesn't reflect the previous
protocol.

Don't extract the encapsulated protocol in the VLAN dissector until you
use it, so that if the frame contains the VLAN ID but not the
encapsulated protocol, we at least put the VLAN ID into the protocol
tree.

svn path=/trunk/; revision=2927
2001-01-21 22:51:46 +00:00

573 lines
16 KiB
C
Raw Blame History

/* packet-llc.c
* Routines for IEEE 802.2 LLC layer
* Gilbert Ramirez <gram@xiexie.org>
*
* $Id: packet-llc.c,v 1.82 2001/01/21 22:51:46 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 "bridged_pids.h"
#include "packet-ip.h"
#include "packet-ipx.h"
#include "packet-netbios.h"
#include "packet-osi.h"
#include "packet-sna.h"
#include "packet-llc.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_table_t cisco_subdissector_table;
static dissector_handle_t bpdu_handle;
static dissector_handle_t eth_handle;
static dissector_handle_t fddi_handle;
static dissector_handle_t tr_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" },
{ SAP_X25, "ISO 8208 (X.25 over 802.2)" },
/*
* XXX - setting the group bit of SAP_X25 make 0x7F; is this just
* a group version of that?
*/
{ 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_BRIDGED, "Frame Relay or ATM bridged frames" },
/* RFC 2427, RFC 2684 */
{ 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++;
}
}
}
}
static 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;
guint8 dsap, ssap;
tvbuff_t *next_tvb;
if (check_col(pinfo->fd, COL_PROTOCOL)) {
col_set_str(pinfo->fd, COL_PROTOCOL, "LLC");
}
if (check_col(pinfo->fd, COL_INFO)) {
col_clear(pinfo->fd, COL_INFO);
}
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) {
dissect_snap(tvb, 3, pinfo, tree, llc_tree, control,
hf_llc_oui, hf_llc_type, hf_llc_pid, 2);
}
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);
}
}
}
/*
* Dissect SNAP header; used elsewhere, e.g. in the Frame Relay dissector.
*/
void
dissect_snap(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree,
proto_tree *snap_tree, int control, int hf_oui, int hf_type, int hf_pid,
int bridge_pad)
{
guint32 oui;
guint16 etype;
tvbuff_t *next_tvb;
oui = tvb_get_ntoh24(tvb, offset);
etype = tvb_get_ntohs(tvb, offset+3);
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(snap_tree, hf_oui, tvb, offset, 3, oui);
}
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, offset+5,
pinfo, tree, snap_tree, hf_type, -1);
} else {
next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
dissect_data(next_tvb, 0, pinfo, tree);
}
break;
case OUI_BRIDGED:
/*
* MAC frames bridged over ATM (RFC 2684) or Frame Relay
* (RFC 2427).
*
* We have to figure out how much padding to put
* into the frame. We were handed a "bridge_pad"
* argument which should be 0 for Frame Relay and
* 2 for ATM; we add to that the amount of padding
* common to both bridging types.
*/
if (tree) {
proto_tree_add_uint(snap_tree, hf_pid, tvb, offset+3, 2,
etype);
}
switch (etype) {
case BPID_ETH_WITH_FCS:
case BPID_ETH_WITHOUT_FCS:
next_tvb = tvb_new_subset(tvb, offset+5+bridge_pad,
-1, -1);
call_dissector(eth_handle, next_tvb, pinfo, tree);
break;
case BPID_802_5_WITH_FCS:
case BPID_802_5_WITHOUT_FCS:
/*
* We treat the last padding byte as the Access
* Control byte, as that's what the Token
* Ring dissector expects the first byte to
* be.
*/
next_tvb = tvb_new_subset(tvb, offset+5+bridge_pad,
-1, -1);
call_dissector(tr_handle, next_tvb, pinfo, tree);
break;
case BPID_FDDI_WITH_FCS:
case BPID_FDDI_WITHOUT_FCS:
next_tvb = tvb_new_subset(tvb, offset+5+1+bridge_pad,
-1, -1);
call_dissector(fddi_handle, next_tvb, pinfo, tree);
break;
case BPID_BPDU:
next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
call_dissector(bpdu_handle, next_tvb, pinfo, tree);
break;
default:
next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
dissect_data(next_tvb, 0, pinfo, tree);
break;
}
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(snap_tree, hf_pid, tvb, offset+3, 2,
etype);
}
next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
if (XDLC_IS_INFORMATION(control)) {
/* do lookup with the subdissector table */
/* for future reference, 0x0102 is Cisco DRIP */
if (!dissector_try_port(cisco_subdissector_table,
etype, next_tvb, pinfo, tree))
dissect_data(next_tvb, 0, pinfo, tree);
} 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(snap_tree, hf_pid, tvb, offset+3, 2,
etype);
}
next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
call_dissector(bpdu_handle, next_tvb, pinfo, tree);
break;
default:
if (tree) {
proto_tree_add_uint(snap_tree, hf_pid, tvb, offset+3, 2,
etype);
}
next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
dissect_data(next_tvb, 0, pinfo, tree);
break;
}
}
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", "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");
cisco_subdissector_table = register_dissector_table("llc.cisco_pid");
register_dissector("llc", dissect_llc, proto_llc);
}
void
proto_reg_handoff_llc(void)
{
/*
* Get handles for the BPDU, Ethernet, FDDI, and Token Ring
* dissectors.
*/
bpdu_handle = find_dissector("bpdu");
eth_handle = find_dissector("eth");
fddi_handle = find_dissector("fddi");
tr_handle = find_dissector("tr");
dissector_add("wtap_encap", WTAP_ENCAP_ATM_RFC1483, dissect_llc,
proto_llc);
}
View git blame Copy permalink