Don't let the user specify a maximum capture file size if they're not
[obnox/wireshark/wip.git] / packet-llc.c
1 /* packet-llc.c
2  * Routines for IEEE 802.2 LLC layer
3  * Gilbert Ramirez <gram@alumni.rice.edu>
4  *
5  * $Id: packet-llc.c,v 1.93 2001/12/10 00:25:30 guy Exp $
6  *
7  * Ethereal - Network traffic analyzer
8  * By Gerald Combs <gerald@ethereal.com>
9  * Copyright 1998 Gerald Combs
10  * 
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public License
13  * as published by the Free Software Foundation; either version 2
14  * of the License, or (at your option) any later version.
15  * 
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  * 
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
24  */
25
26 #ifdef HAVE_CONFIG_H
27 # include "config.h"
28 #endif
29
30 #ifdef HAVE_SYS_TYPES_H
31 # include <sys/types.h>
32 #endif
33
34 #include <glib.h>
35 #include "packet.h"
36 #include "oui.h"
37 #include "xdlc.h"
38 #include "etypes.h"
39 #include "llcsaps.h"
40 #include "bridged_pids.h"
41 #include "packet-ip.h"
42 #include "packet-ipx.h"
43 #include "packet-netbios.h"
44 #include "sna-utils.h"
45
46 #include "packet-llc.h"
47
48 static int proto_llc = -1;
49 static int hf_llc_dsap = -1;
50 static int hf_llc_ssap = -1;
51 static int hf_llc_dsap_ig = -1;
52 static int hf_llc_ssap_cr = -1;
53 static int hf_llc_ctrl = -1;
54 static int hf_llc_type = -1;
55 static int hf_llc_oui = -1;
56 static int hf_llc_pid = -1;
57
58 static gint ett_llc = -1;
59 static gint ett_llc_ctrl = -1;
60
61 static dissector_table_t subdissector_table;
62 static dissector_table_t cisco_subdissector_table;
63
64 static dissector_handle_t bpdu_handle;
65 static dissector_handle_t eth_handle;
66 static dissector_handle_t fddi_handle;
67 static dissector_handle_t tr_handle;
68 static dissector_handle_t data_handle;
69
70 typedef void (capture_func_t)(const u_char *, int, int, packet_counts *);
71
72 /* The SAP info is split into two tables, one value_string table and one
73  * table of sap_info. This is so that the value_string can be used in the
74  * header field registration.
75  */
76 struct sap_info {
77         guint8  sap;
78         capture_func_t *capture_func;
79 };
80
81 /*
82  * Group/Individual bit, in the DSAP.
83  */
84 #define DSAP_GI_BIT     0x01
85
86 /*
87  * Command/Response bit, in the SSAP.
88  *
89  * The low-order bit of the SSAP apparently determines whether this
90  * is a request or a response.  (RFC 1390, "Transmission of IP and
91  * ARP over FDDI Networks", says
92  *
93  *      Command frames are identified by having the low order
94  *      bit of the SSAP address reset to zero.  Response frames
95  *      have the low order bit of the SSAP address set to one.
96  *
97  * and a page I've seen seems to imply that's part of 802.2.)
98  */
99 #define SSAP_CR_BIT     0x01
100
101 /*
102  * Mask to extrace the SAP number from the DSAP or the SSAP.
103  */
104 #define SAP_MASK        0xFE
105
106 /*
107  * These are for SSAP and DSAP, wth last bit always zero.
108  * XXX - some DSAPs come in separate "individual" and "group" versions,
109  * with the last bit 0 and 1, respectively (e.g., LLC Sub-layer Management,
110  * IBM SNA Path Control, IBM Net Management), but, whilst 0xFE is
111  * the ISO Network Layer Protocol, 0xFF is the Global LSAP.
112  */
113 static const value_string sap_vals[] = {
114         { SAP_NULL,           "NULL LSAP" },
115         { SAP_LLC_SLMGMT,     "LLC Sub-Layer Management" },
116         { SAP_SNA_PATHCTRL,   "SNA Path Control" },
117         { SAP_IP,             "TCP/IP" },
118         { SAP_SNA1,           "SNA" },
119         { SAP_SNA2,           "SNA" },
120         { SAP_PROWAY_NM_INIT, "PROWAY (IEC955) Network Management and Initialization" },
121         { SAP_TI,             "Texas Instruments" },
122         { SAP_BPDU,           "Spanning Tree BPDU" },
123         { SAP_RS511,          "EIA RS-511 Manufacturing Message Service" },
124         { SAP_X25,            "ISO 8208 (X.25 over 802.2)" },
125         /*
126          * XXX - setting the group bit of SAP_X25 make 0x7F; is this just
127          * a group version of that?
128          */
129         { 0x7F,               "ISO 802.2" },
130         { SAP_XNS,            "XNS" },
131         { SAP_NESTAR,         "Nestar" },
132         { SAP_PROWAY_ASLM,    "PROWAY (IEC955) Active Station List Maintenance" },
133         { SAP_ARP,            "ARP" },  /* XXX - hand to "dissect_arp()"? */
134         { SAP_SNAP,           "SNAP" },
135         { SAP_VINES1,         "Banyan Vines" },
136         { SAP_VINES2,         "Banyan Vines" },
137         { SAP_NETWARE,        "NetWare" },
138         { SAP_NETBIOS,        "NetBIOS" },
139         { SAP_IBMNM,          "IBM Net Management" },
140         { SAP_RPL1,           "Remote Program Load" },
141         { SAP_UB,             "Ungermann-Bass" },
142         { SAP_RPL2,           "Remote Program Load" },
143         { SAP_OSINL,          "ISO Network Layer" },
144         { SAP_GLOBAL,         "Global LSAP" },
145         { 0x00,               NULL }
146 };
147
148 static struct sap_info  saps[] = {
149         { SAP_IP,                       capture_ip },
150         { SAP_NETWARE,                  capture_ipx },
151         { SAP_NETBIOS,                  capture_netbios },
152         { 0x00,                         NULL}
153 };
154
155 /*
156  * See
157  *
158  * http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/vlan.htm
159  *
160  * for the PIDs for VTP and DRiP that go with an OUI of OUI_CISCO.
161  */
162 const value_string oui_vals[] = {
163         { OUI_ENCAP_ETHER, "Encapsulated Ethernet" },
164 /*
165 http://www.cisco.com/univercd/cc/td/doc/product/software/ios113ed/113ed_cr/ibm_r/brprt1/brsrb.htm
166 */
167         { OUI_CISCO,       "Cisco" },
168         { OUI_CISCO_90,    "Cisco IOS 9.0 Compatible" },
169         { OUI_BRIDGED,     "Frame Relay or ATM bridged frames" },
170                                 /* RFC 2427, RFC 2684 */
171         { OUI_ATM_FORUM,   "ATM Forum" },
172         { OUI_CABLE_BPDU,  "DOCSIS Spanning Tree" }, /* DOCSIS spanning tree BPDU */
173         { OUI_APPLE_ATALK, "Apple (AppleTalk)" },
174         { 0,               NULL }
175 };
176
177 static capture_func_t *
178 sap_capture_func(u_char sap) {
179         int i=0;
180
181         /* look for the second record where sap == 0, which should
182          * be the last record
183          */
184         while (saps[i].sap > 0 || i == 0) {
185                 if (saps[i].sap == sap) {
186                         return saps[i].capture_func;
187                 }
188                 i++;
189         }
190         return NULL;
191 }
192
193 void
194 capture_llc(const u_char *pd, int offset, int len, packet_counts *ld) {
195
196         int             is_snap;
197         guint16         control;
198         int             llc_header_len;
199         guint32         oui;
200         guint16         etype;
201         capture_func_t  *capture;
202
203         if (!BYTES_ARE_IN_FRAME(offset, len, 2)) {
204                 ld->other++;
205                 return;
206         }
207         is_snap = (pd[offset] == SAP_SNAP) && (pd[offset+1] == SAP_SNAP);
208         llc_header_len = 2;     /* DSAP + SSAP */
209
210         /*
211          * XXX - the page referred to in the comment above about the
212          * Command/Response bit also implies that LLC Type 2 always
213          * uses extended operation, so we don't need to determine
214          * whether it's basic or extended operation; is that the case?
215          */
216         control = get_xdlc_control(pd, offset+2, pd[offset+1] & SSAP_CR_BIT,
217             TRUE);
218         llc_header_len += XDLC_CONTROL_LEN(control, TRUE);
219         if (is_snap)
220                 llc_header_len += 5;    /* 3 bytes of OUI, 2 bytes of protocol ID */
221         if (!BYTES_ARE_IN_FRAME(offset, len, llc_header_len)) {
222                 ld->other++;
223                 return;
224         }
225
226         if (is_snap) {
227                 oui = pd[offset+3] << 16 | pd[offset+4] << 8 | pd[offset+5];
228                 if (XDLC_IS_INFORMATION(control)) {
229                         etype = pntohs(&pd[offset+6]);
230                         switch (oui) {
231
232                         case OUI_ENCAP_ETHER:
233                         case OUI_CISCO_90:
234                         case OUI_APPLE_ATALK:
235                                 /* No, I have no idea why Apple used
236                                    one of their own OUIs, rather than
237                                    OUI_ENCAP_ETHER, and an Ethernet
238                                    packet type as protocol ID, for
239                                    AppleTalk data packets - but used
240                                    OUI_ENCAP_ETHER and an Ethernet
241                                    packet type for AARP packets. */
242                                 capture_ethertype(etype, pd, offset+8, len,
243                                     ld);
244                                 break;
245                         case OUI_CISCO:
246                                 capture_ethertype(etype, pd, offset + 8, len,
247                                     ld);
248                                 break;
249                         default:
250                                 ld->other++;
251                                 break;
252                         }
253                 }
254         }               
255         else {
256                 if (XDLC_IS_INFORMATION(control)) {
257                         capture = sap_capture_func(pd[offset]);
258
259                         /* non-SNAP */
260                         offset += llc_header_len;
261
262                         if (capture) {
263                                 capture(pd, offset, len, ld);
264                         }
265                         else {
266                                 ld->other++;
267                         }
268                 }
269         }
270 }
271
272 static void
273 dissect_llc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
274 {
275         proto_tree      *llc_tree = NULL;
276         proto_item      *ti = NULL;
277         int             is_snap;
278         guint16         control;
279         int             llc_header_len;
280         guint8          dsap, ssap;
281         tvbuff_t        *next_tvb;
282
283         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
284                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "LLC");
285         }
286         if (check_col(pinfo->cinfo, COL_INFO)) {
287                 col_clear(pinfo->cinfo, COL_INFO);
288         }
289
290         dsap = tvb_get_guint8(tvb, 0);
291         if (tree) {
292                 ti = proto_tree_add_item(tree, proto_llc, tvb, 0, 0, FALSE);
293                 llc_tree = proto_item_add_subtree(ti, ett_llc);
294                 proto_tree_add_uint(llc_tree, hf_llc_dsap, tvb, 0, 
295                         1, dsap & SAP_MASK);
296                 proto_tree_add_boolean(llc_tree, hf_llc_dsap_ig, tvb, 0, 
297                         1, dsap & DSAP_GI_BIT);
298         } else
299                 llc_tree = NULL;
300
301         ssap = tvb_get_guint8(tvb, 1);
302         if (tree) {
303                 proto_tree_add_uint(llc_tree, hf_llc_ssap, tvb, 1, 
304                         1, ssap & SAP_MASK);
305                 proto_tree_add_boolean(llc_tree, hf_llc_ssap_cr, tvb, 1, 
306                         1, ssap & SSAP_CR_BIT);
307         } else
308                 llc_tree = NULL;
309
310         is_snap = (dsap == SAP_SNAP) && (ssap == SAP_SNAP);
311         llc_header_len = 2;     /* DSAP + SSAP */
312
313         /*
314          * XXX - the page referred to in the comment above about the
315          * Command/Response bit also implies that LLC Type 2 always
316          * uses extended operation, so we don't need to determine
317          * whether it's basic or extended operation; is that the case?
318          */
319         control = dissect_xdlc_control(tvb, 2, pinfo, llc_tree,
320                                 hf_llc_ctrl, ett_llc_ctrl,
321                                 ssap & SSAP_CR_BIT, TRUE);
322         llc_header_len += XDLC_CONTROL_LEN(control, TRUE);
323         if (is_snap)
324                 llc_header_len += 5;    /* 3 bytes of OUI, 2 bytes of protocol ID */
325
326         if (tree)
327                 proto_item_set_len(ti, llc_header_len);
328
329         if (is_snap) {
330                 dissect_snap(tvb, 3, pinfo, tree, llc_tree, control,
331                     hf_llc_oui, hf_llc_type, hf_llc_pid, 2);
332         }
333         else {
334                 if (check_col(pinfo->cinfo, COL_INFO)) {
335                         col_append_fstr(pinfo->cinfo, COL_INFO, 
336                             "; DSAP %s %s, SSAP %s %s",
337                             val_to_str(dsap & SAP_MASK, sap_vals, "%02x"),
338                             dsap & DSAP_GI_BIT ?
339                               "Group" : "Individual",
340                             val_to_str(ssap & SAP_MASK, sap_vals, "%02x"),
341                             ssap & SSAP_CR_BIT ?
342                               "Response" : "Command"
343                         );
344                 }
345
346                 next_tvb = tvb_new_subset(tvb, llc_header_len, -1, -1);
347                 if (XDLC_IS_INFORMATION(control)) {
348                         /* non-SNAP */
349                         /* do lookup with the subdissector table */
350                         if (!dissector_try_port(subdissector_table, dsap,
351                             next_tvb, pinfo, tree)) {
352                                 call_dissector(data_handle,next_tvb, pinfo, tree);
353                         }
354                 } else {
355                         call_dissector(data_handle,next_tvb, pinfo, tree);
356                 }
357         }
358 }
359
360 /*
361  * Dissect SNAP header; used elsewhere, e.g. in the Frame Relay dissector.
362  */
363 void
364 dissect_snap(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree,
365     proto_tree *snap_tree, int control, int hf_oui, int hf_type, int hf_pid,
366     int bridge_pad)
367 {
368         guint32         oui;
369         guint16         etype;
370         tvbuff_t        *next_tvb;
371
372         oui =   tvb_get_ntoh24(tvb, offset);
373         etype = tvb_get_ntohs(tvb, offset+3);
374
375         if (check_col(pinfo->cinfo, COL_INFO)) {
376                 col_append_fstr(pinfo->cinfo, COL_INFO,
377                     "; SNAP, OUI 0x%06X (%s), PID 0x%04X",
378                     oui, val_to_str(oui, oui_vals, "Unknown"), etype);
379         }
380         if (tree) {
381                 proto_tree_add_uint(snap_tree, hf_oui, tvb, offset, 3, oui);
382         }
383
384         switch (oui) {
385
386         case OUI_ENCAP_ETHER:
387         case OUI_CISCO_90:
388         case OUI_APPLE_ATALK:
389                 /* No, I have no idea why Apple used
390                    one of their own OUIs, rather than
391                    OUI_ENCAP_ETHER, and an Ethernet
392                    packet type as protocol ID, for
393                    AppleTalk data packets - but used
394                    OUI_ENCAP_ETHER and an Ethernet
395                    packet type for AARP packets. */
396                 if (XDLC_IS_INFORMATION(control)) {
397                         ethertype(etype, tvb, offset+5,
398                             pinfo, tree, snap_tree, hf_type, -1);
399                 } else {
400                         next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
401                         call_dissector(data_handle,next_tvb, pinfo, tree);
402                 }
403                 break;
404
405         case OUI_BRIDGED:
406                 /*
407                  * MAC frames bridged over ATM (RFC 2684) or Frame Relay
408                  * (RFC 2427).
409                  *
410                  * We have to figure out how much padding to put
411                  * into the frame.  We were handed a "bridge_pad"
412                  * argument which should be 0 for Frame Relay and
413                  * 2 for ATM; we add to that the amount of padding
414                  * common to both bridging types.
415                  */
416                 if (tree) {
417                         proto_tree_add_uint(snap_tree, hf_pid, tvb, offset+3, 2,
418                             etype);
419                 }
420
421                 switch (etype) {
422
423                 case BPID_ETH_WITH_FCS:
424                 case BPID_ETH_WITHOUT_FCS:
425                         next_tvb = tvb_new_subset(tvb, offset+5+bridge_pad,
426                             -1, -1);
427                         call_dissector(eth_handle, next_tvb, pinfo, tree);
428                         break;
429
430                 case BPID_802_5_WITH_FCS:
431                 case BPID_802_5_WITHOUT_FCS:
432                         /*
433                          * We treat the last padding byte as the Access
434                          * Control byte, as that's what the Token
435                          * Ring dissector expects the first byte to
436                          * be.
437                          */
438                         next_tvb = tvb_new_subset(tvb, offset+5+bridge_pad,
439                             -1, -1);
440                         call_dissector(tr_handle, next_tvb, pinfo, tree);
441                         break;
442
443                 case BPID_FDDI_WITH_FCS:
444                 case BPID_FDDI_WITHOUT_FCS:
445                         next_tvb = tvb_new_subset(tvb, offset+5+1+bridge_pad,
446                             -1, -1);
447                         call_dissector(fddi_handle, next_tvb, pinfo, tree);
448                         break;
449
450                 case BPID_BPDU:
451                         next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
452                         call_dissector(bpdu_handle, next_tvb, pinfo, tree);
453                         break;
454
455                 default:
456                         next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
457                         call_dissector(data_handle,next_tvb, pinfo, tree);
458                         break;
459                 }
460                 break;
461                 
462         case OUI_CISCO:
463                 /* So are all CDP packets LLC packets
464                    with an OUI of OUI_CISCO and a
465                    protocol ID of 0x2000, or
466                    are some of them raw or encapsulated
467                    Ethernet? */
468                 if (tree) {
469                         proto_tree_add_uint(snap_tree, hf_pid, tvb, offset+3, 2,
470                             etype);
471                 }
472                 next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
473                 if (XDLC_IS_INFORMATION(control)) {
474                         /* do lookup with the subdissector table */
475                         /* for future reference, 0x0102 is Cisco DRIP */
476                         if (!dissector_try_port(cisco_subdissector_table,
477                             etype, next_tvb, pinfo, tree))
478                                 call_dissector(data_handle,next_tvb, pinfo, tree);
479                 } else
480                         call_dissector(data_handle,next_tvb, pinfo, tree);
481                 break;
482
483         case OUI_CABLE_BPDU:    /* DOCSIS cable modem spanning tree BPDU */
484                 if (tree) {
485                         proto_tree_add_uint(snap_tree, hf_pid, tvb, offset+3, 2,
486                             etype);
487                 }
488                 next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
489                 call_dissector(bpdu_handle, next_tvb, pinfo, tree);
490                 break;
491
492         default:
493                 if (tree) {
494                         proto_tree_add_uint(snap_tree, hf_pid, tvb, offset+3, 2,
495                             etype);
496                 }
497                 next_tvb = tvb_new_subset(tvb, offset+5, -1, -1);
498                 call_dissector(data_handle,next_tvb, pinfo, tree);
499                 break;
500         }
501 }
502
503 void
504 proto_register_llc(void)
505 {
506         static struct true_false_string ig_bit = { "Group", "Individual" };
507         static struct true_false_string cr_bit = { "Response", "Command" };
508
509         static hf_register_info hf[] = {
510                 { &hf_llc_dsap,
511                 { "DSAP",       "llc.dsap", FT_UINT8, BASE_HEX, 
512                         VALS(sap_vals), 0x0, "", HFILL }},
513
514                 { &hf_llc_dsap_ig,
515                 { "IG Bit",     "llc.dsap.ig", FT_BOOLEAN, BASE_HEX, 
516                         &ig_bit, 0x0, "Individual/Group", HFILL }},
517
518                 { &hf_llc_ssap,
519                 { "SSAP", "llc.ssap", FT_UINT8, BASE_HEX, 
520                         VALS(sap_vals), 0x0, "", HFILL }},
521
522                 { &hf_llc_ssap_cr,
523                 { "CR Bit", "llc.ssap.cr", FT_BOOLEAN, BASE_HEX, 
524                         &cr_bit, 0x0, "Command/Response", HFILL }},
525
526                 { &hf_llc_ctrl,
527                 { "Control", "llc.control", FT_UINT16, BASE_HEX, 
528                         NULL, 0x0, "", HFILL }},
529
530                 /* registered here but handled in ethertype.c */
531                 { &hf_llc_type,
532                 { "Type", "llc.type", FT_UINT16, BASE_HEX, 
533                         VALS(etype_vals), 0x0, "", HFILL }},
534
535                 { &hf_llc_oui,
536                 { "Organization Code",  "llc.oui", FT_UINT24, BASE_HEX, 
537                         VALS(oui_vals), 0x0, "", HFILL }},
538
539                 { &hf_llc_pid,
540                 { "Protocol ID", "llc.pid", FT_UINT16, BASE_HEX, 
541                         NULL, 0x0, "", HFILL }}
542         };
543         static gint *ett[] = {
544                 &ett_llc,
545                 &ett_llc_ctrl,
546         };
547
548         proto_llc = proto_register_protocol("Logical-Link Control", "LLC", "llc");
549         proto_register_field_array(proto_llc, hf, array_length(hf));
550         proto_register_subtree_array(ett, array_length(ett));
551
552 /* subdissector code */
553         subdissector_table = register_dissector_table("llc.dsap",
554           "LLC SAP", FT_UINT8, BASE_HEX);
555         cisco_subdissector_table = register_dissector_table("llc.cisco_pid",
556           "Cisco OUI PID", FT_UINT16, BASE_HEX);
557
558         register_dissector("llc", dissect_llc, proto_llc);
559 }
560
561 void
562 proto_reg_handoff_llc(void)
563 {
564         dissector_handle_t llc_handle;
565
566         /*
567          * Get handles for the BPDU, Ethernet, FDDI, and Token Ring
568          * dissectors.
569          */
570         bpdu_handle = find_dissector("bpdu");
571         eth_handle = find_dissector("eth");
572         fddi_handle = find_dissector("fddi");
573         tr_handle = find_dissector("tr");
574         data_handle = find_dissector("data");
575
576         llc_handle = find_dissector("llc");
577         dissector_add("wtap_encap", WTAP_ENCAP_ATM_RFC1483, llc_handle);
578 }