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Revert "TODO epan/dissectors/asn1/kerberos/packet-kerberos-template.c new GSS flags"
[wireshark-sm.git] / epan / dissectors / packet-gre.c
blob124fb6144d6aa19188fd6963519f5af0893e68bd
1 /* packet-gre.c
2 * Routines for the Generic Routing Encapsulation (GRE) protocol
3 * Brad Robel-Forrest <brad.robel-forrest@watchguard.com>
4 *
5 * Wireshark - Network traffic analyzer
6 * By Gerald Combs <gerald@wireshark.org>
7 * Copyright 1998 Gerald Combs
8 *
9 * SPDX-License-Identifier: GPL-2.0-or-later
10 */
11
12 #include "config.h"
13
14 #include <epan/packet.h>
15 #include <epan/tfs.h>
16 #include <epan/capture_dissectors.h>
17 #include <epan/etypes.h>
18 #include <epan/in_cksum.h>
19 #include <epan/expert.h>
20 #include <epan/ipproto.h>
21 #include <epan/llcsaps.h>
22 #include "packet-gre.h"
23 #include "packet-wccp.h"
24
25 #include <epan/decode_as.h>
26
27 #define GRE_IN_UDP_PORT 4754
28
29 void proto_register_gre(void);
30 void proto_reg_handoff_gre(void);
31
32 static dissector_handle_t gre_handle;
33 static capture_dissector_handle_t gre_cap_handle;
34
35
36 /*
37 * See RFC 1701 "Generic Routing Encapsulation (GRE)", RFC 1702
38 * "Generic Routing Encapsulation over IPv4 networks", RFC 2637
39 * "Point-to-Point Tunneling Protocol (PPTP)", RFC 2784 "Generic
40 * Routing Encapsulation (GRE)", RFC 2890 "Key and Sequence
41 * Number Extensions to GRE", RFC 8086 "GRE-in-UDP Encapsulation",
42 * and draft-ietf-mpls-in-ip-or-gre-07.txt
43 * "Encapsulating MPLS in IP or Generic Routing Encapsulation (GRE)".
44 */
45
46 static int proto_gre;
47 static int hf_gre_proto;
48 static int hf_gre_flags_and_version;
49 static int hf_gre_flags_checksum;
50 static int hf_gre_flags_routing;
51 static int hf_gre_flags_key;
52 static int hf_gre_flags_sequence_number;
53 static int hf_gre_flags_strict_source_route;
54 static int hf_gre_flags_recursion_control;
55 static int hf_gre_flags_ack;
56 static int hf_gre_flags_reserved_ppp;
57 static int hf_gre_flags_reserved;
58 static int hf_gre_flags_version;
59 static int hf_gre_checksum;
60 static int hf_gre_checksum_status;
61 static int hf_gre_offset;
62 static int hf_gre_key;
63 static int hf_gre_key_payload_length;
64 static int hf_gre_key_call_id;
65 static int hf_gre_sequence_number;
66 static int hf_gre_ack_number;
67 static int hf_gre_routing;
68 static int hf_gre_routing_address_family;
69 static int hf_gre_routing_sre_length;
70 static int hf_gre_routing_sre_offset;
71 static int hf_gre_routing_information;
72
73 /* Ref 3GPP2 A.S0012-C v2.0 and A.S0008-A v1.0 */
74 static int hf_gre_3gpp2_attrib;
75 static int hf_gre_3gpp2_attrib_id;
76 static int hf_gre_3gpp2_attrib_length;
77 static int hf_gre_3gpp2_sdi;
78 static int hf_gre_3gpp2_fci;
79 static int hf_gre_3gpp2_di;
80 static int hf_gre_3gpp2_flow_disc;
81 static int hf_gre_3gpp2_seg;
82
83 static int hf_gre_wccp_redirect_header;
84 static int hf_gre_wccp_dynamic_service;
85 static int hf_gre_wccp_alternative_bucket_used;
86 static int hf_gre_wccp_redirect_header_valid;
87 static int hf_gre_wccp_service_id;
88 static int hf_gre_wccp_alternative_bucket;
89 static int hf_gre_wccp_primary_bucket;
90
91 static int ett_gre;
92 static int ett_gre_flags;
93 static int ett_gre_routing;
94 static int ett_gre_wccp2_redirect_header;
95 static int ett_3gpp2_attribs;
96 static int ett_3gpp2_attr;
97
98 static expert_field ei_gre_checksum_incorrect;
99
100 static dissector_table_t gre_dissector_table;
101
102 static dissector_table_t gre_subdissector_table;
103
104 static const value_string gre_version[] = {
105 { 0, "GRE" }, /* [RFC2784] */
106 { 1, "Enhanced GRE" }, /* [RFC2637] */
107 { 0, NULL}
108 };
109 const value_string gre_typevals[] = {
110 { GRE_KEEPALIVE, "Possible GRE keepalive packet" },
111 { ETHERTYPE_PPP, "PPP" },
112 { ETHERTYPE_IP, "IP" },
113 { ETHERTYPE_ARP, "ARP" },
114 { SAP_OSINL5, "OSI"},
115 { GRE_WCCP, "WCCP"},
116 { GRE_CISCO_CDP, "CDP (Cisco)"},
117 { GRE_NHRP, "NHRP"},
118 { GRE_ERSPAN_88BE, "ERSPAN"},
119 { GRE_ERSPAN_22EB, "ERSPAN III"},
120 { GRE_MIKROTIK_EOIP, "MIKROTIK EoIP"},
121 { GRE_AIROHIVE, "AIROHIVE AP AP"},
122 { ETHERTYPE_IPX, "IPX"},
123 { ETHERTYPE_ETHBRIDGE, "Transparent Ethernet bridging" },
124 { ETHERTYPE_RAW_FR, "Frame Relay"},
125 { ETHERTYPE_IPv6, "IPv6" },
126 { ETHERTYPE_MPLS, "MPLS label switched packet" },
127 { ETHERTYPE_NSH, "Network Service Header" },
128 { ETHERTYPE_CDMA2000_A10_UBS,"CDMA2000 A10 Unstructured byte stream" },
129 { ETHERTYPE_3GPP2, "CDMA2000 A10 3GPP2 Packet" },
130 { ETHERTYPE_CMD, "CiscoMetaData" },
131 { GRE_GREBONDING, "Huawei GRE bonding" },
132 { GRE_ARUBA_8200, "ARUBA WLAN" },
133 { GRE_ARUBA_8210, "ARUBA WLAN" },
134 { GRE_ARUBA_8220, "ARUBA WLAN" },
135 { GRE_ARUBA_8230, "ARUBA WLAN" },
136 { GRE_ARUBA_8240, "ARUBA WLAN" },
137 { GRE_ARUBA_8250, "ARUBA WLAN" },
138 { GRE_ARUBA_8260, "ARUBA WLAN" },
139 { GRE_ARUBA_8270, "ARUBA WLAN" },
140 { GRE_ARUBA_8280, "ARUBA WLAN" },
141 { GRE_ARUBA_8290, "ARUBA WLAN" },
142 { GRE_ARUBA_82A0, "ARUBA WLAN" },
143 { GRE_ARUBA_82B0, "ARUBA WLAN" },
144 { GRE_ARUBA_82C0, "ARUBA WLAN" },
145 { GRE_ARUBA_82D0, "ARUBA WLAN" },
146 { GRE_ARUBA_82E0, "ARUBA WLAN" },
147 { GRE_ARUBA_82F0, "ARUBA WLAN" },
148 { GRE_ARUBA_8300, "ARUBA WLAN" },
149 { GRE_ARUBA_8310, "ARUBA WLAN" },
150 { GRE_ARUBA_8320, "ARUBA WLAN" },
151 { GRE_ARUBA_8330, "ARUBA WLAN" },
152 { GRE_ARUBA_8340, "ARUBA WLAN" },
153 { GRE_ARUBA_8350, "ARUBA WLAN" },
154 { GRE_ARUBA_8360, "ARUBA WLAN" },
155 { GRE_ARUBA_8370, "ARUBA WLAN" },
156 { GRE_ARUBA_9000, "ARUBA WLAN" },
157 { GRE_ARUBA_9100, "ARUBA WLAN" },
158 { GRE_ARUBA_9110, "ARUBA WLAN" },
159 { GRE_ARUBA_9120, "ARUBA WLAN" },
160 { GRE_ARUBA_9130, "ARUBA WLAN" },
161 { GRE_ARUBA_9140, "ARUBA WLAN" },
162 { GRE_ARUBA_9150, "ARUBA WLAN" },
163 { GRE_ARUBA_9160, "ARUBA WLAN" },
164 { GRE_ARUBA_9170, "ARUBA WLAN" },
165 { GRE_ARUBA_9180, "ARUBA WLAN" },
166 { GRE_ARUBA_9190, "ARUBA WLAN" },
167 { GRE_ARUBA_91A0, "ARUBA WLAN" },
168 { GRE_ARUBA_91B0, "ARUBA WLAN" },
169 { GRE_ARUBA_91C0, "ARUBA WLAN" },
170 { GRE_ARUBA_91D0, "ARUBA WLAN" },
171 { GRE_ARUBA_91E0, "ARUBA WLAN" },
172 { GRE_ARUBA_91F0, "ARUBA WLAN" },
173 { 0, NULL }
174 };
175
176 #define ID_3GPP2_SDI_FLAG 1
177 #define ID_3GPP2_FLOW_CTRL 2
178 #define ID_3GPP2_FLOW_DISCRIMINATOR 3
179 #define ID_3GPP2_SEG 4
180
181 static const value_string gre_3gpp2_seg_vals[] = {
182 { 0x00, "Packet Started" },
183 { 0x01, "Packet continued" },
184 { 0x02, "Packet Ended" },
185 { 0, NULL }
186 };
187 /* 3GPP2 A.S0012-C v2.0
188 * 2.6.1 GRE Attributes
189 */
190 static const value_string gre_3gpp2_attrib_id_vals[] = {
191 { 0x01, "1x SDB/HRPD DOS Indicator" },
192 { 0x02, "Flow Control Indication" },
193 /* A.S0008-A v1.0 */
194 { 0x03, "IP Flow Discriminator" },
195 { 0x04, "Segmentation Indication" },
196 { 0, NULL }
197 };
198
199 static const true_false_string gre_3gpp2_sdi_val = {
200 "Packet suitable for 1x SDB or HRPD DOS transmission",
201 "Reserved"
202 };
203
204 static const true_false_string gre_3gpp2_fci_val = {
205 "XOFF",
206 "XON"
207 };
208
209 static const true_false_string gre_3gpp2_di_val = {
210 "INDEFINITE:",
211 "TEMPORARY"
212 };
213
214 static const true_false_string gre_wccp_dynamic_service_val = {
215 "Dynamic service",
216 "Well-known service"
217 };
218
219 static const true_false_string gre_wccp_alternative_bucket_used_val = {
220 "Alternative bucket used",
221 "Primary bucket used",
222 };
223
224 static const true_false_string gre_wccp_redirect_header_valid_val = {
225 "Header is present, but ignore contents",
226 "Header contents are valid",
227 };
228
229
230 static int
231 dissect_gre_3gpp2_attribs(tvbuff_t *tvb, int offset, proto_tree *tree)
232 {
233 bool last_attrib = false;
234 proto_item *attr_item;
235 proto_tree *attr_tree;
236 uint8_t value;
237 int start_offset = offset;
238
239 proto_item *ti = proto_tree_add_item(tree, hf_gre_3gpp2_attrib, tvb, offset, 0, ENC_NA);
240 proto_tree *atree = proto_item_add_subtree(ti, ett_3gpp2_attribs);
241
242 while(last_attrib != true)
243 {
244 uint8_t attrib_id = tvb_get_uint8(tvb, offset);
245 uint8_t attrib_length = tvb_get_uint8(tvb, offset + 1);
246
247 attr_tree = proto_tree_add_subtree(atree, tvb, offset, attrib_length + 1 + 1, ett_3gpp2_attr, &attr_item,
248 val_to_str((attrib_id&0x7f), gre_3gpp2_attrib_id_vals, "%u (Unknown)"));
249
250 proto_tree_add_item(attr_tree, hf_gre_3gpp2_attrib_id, tvb, offset, 1, ENC_BIG_ENDIAN);
251 proto_tree_add_item(attr_tree, hf_gre_3gpp2_attrib_length, tvb, offset+1, 1, ENC_BIG_ENDIAN);
252
253 offset += 2;
254 last_attrib = (attrib_id & 0x80)?true:false;
255 attrib_id &= 0x7F;
256
257 switch(attrib_id)
258 {
259 case ID_3GPP2_FLOW_DISCRIMINATOR:
260 {
261 value = tvb_get_uint8(tvb,offset);
262 proto_tree_add_item(attr_tree, hf_gre_3gpp2_flow_disc, tvb, offset, attrib_length, ENC_NA);
263 proto_item_append_text(attr_item," - 0x%x",value);
264 }
265 break;
266 case ID_3GPP2_SDI_FLAG:
267 {
268 value = tvb_get_uint8(tvb,offset);
269 proto_tree_add_item(attr_tree, hf_gre_3gpp2_sdi, tvb, offset, attrib_length, ENC_BIG_ENDIAN);
270 proto_item_append_text(attr_item," - %s",
271 (value & 0x80) ? "Packet suitable for 1x SDB or HRPD DOS transmission" : "Reserved");
272
273 }
274 break;
275 case ID_3GPP2_SEG:
276 {
277 value = tvb_get_uint8(tvb,offset) >>6;
278 proto_tree_add_item(attr_tree, hf_gre_3gpp2_seg, tvb, offset, attrib_length, ENC_BIG_ENDIAN);
279 proto_item_append_text(attr_item," - %s",val_to_str(value, gre_3gpp2_seg_vals, "0x%02X - Unknown"));
280 }
281 break;
282 case ID_3GPP2_FLOW_CTRL:
283 {
284 value = tvb_get_uint8(tvb,offset);
285 proto_tree_add_item(attr_tree, hf_gre_3gpp2_fci, tvb, offset, attrib_length, ENC_BIG_ENDIAN);
286 proto_item_append_text(attr_item," - %s",
287 (value & 0x80) ? "XON" : "XOFF");
288 proto_tree_add_item(attr_tree, hf_gre_3gpp2_di, tvb, offset, attrib_length, ENC_BIG_ENDIAN);
289 proto_item_append_text(attr_item,"/%s",
290 (value & 0x40) ? "INDEFINITE" : "TEMPORARY");
291 }
292 break;
293 }
294
295 offset += attrib_length;
296 }
297 proto_item_set_len(ti, offset - start_offset);
298
299 return offset;
300 }
301
302 static void
303 dissect_gre_wccp2_redirect_header(tvbuff_t *tvb, int offset, proto_tree *tree)
304 {
305 proto_item *ti;
306 proto_tree *rh_tree;
307
308 ti = proto_tree_add_item(tree, hf_gre_wccp_redirect_header, tvb, offset, 4, ENC_NA);
309 rh_tree = proto_item_add_subtree(ti, ett_gre_wccp2_redirect_header);
310
311 proto_tree_add_item(rh_tree, hf_gre_wccp_dynamic_service, tvb, offset, 1, ENC_BIG_ENDIAN);
312
313 proto_tree_add_item(rh_tree, hf_gre_wccp_alternative_bucket_used, tvb, offset, 1, ENC_BIG_ENDIAN);
314
315 proto_tree_add_item(rh_tree, hf_gre_wccp_redirect_header_valid, tvb, offset, 1, ENC_BIG_ENDIAN);
316
317 proto_tree_add_item(rh_tree, hf_gre_wccp_service_id, tvb, offset +1, 1, ENC_BIG_ENDIAN);
318
319 proto_tree_add_item(rh_tree, hf_gre_wccp_alternative_bucket, tvb, offset +2, 1, ENC_BIG_ENDIAN);
320
321 proto_tree_add_item(rh_tree, hf_gre_wccp_primary_bucket, tvb, offset +3, 1, ENC_BIG_ENDIAN);
322 }
323
324 static bool
325 capture_gre(const unsigned char *pd _U_, int offset _U_, int len _U_, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header _U_)
326 {
327 capture_dissector_increment_count(cpinfo, proto_gre);
328 return true;
329 }
330
331 static int
332 dissect_gre(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
333 {
334
335 int offset = 0;
336 gre_hdr_info_t gre_hdr_info;
337 uint16_t type;
338 bool is_ppp = false;
339 bool is_wccp2 = false;
340 proto_item *ti, *it_flags;
341 proto_tree *gre_tree, *fv_tree = NULL;
342 uint16_t sre_af;
343 uint8_t sre_length;
344 tvbuff_t *next_tvb;
345
346 gre_hdr_info.flags_and_ver = tvb_get_ntohs(tvb, offset);
347 type = tvb_get_ntohs(tvb, offset + 2);
348
349 col_set_str(pinfo->cinfo, COL_PROTOCOL, "GRE");
350
351 col_add_fstr(pinfo->cinfo, COL_INFO, "Encapsulated %s", val_to_str(type, gre_typevals, "0x%04X (unknown)"));
352
353 switch (type) {
354
355 case ETHERTYPE_PPP:
356 if (gre_hdr_info.flags_and_ver & GRE_VERSION)
357 is_ppp = true;
358 break;
359 case ETHERTYPE_3GPP2:
360 case ETHERTYPE_CDMA2000_A10_UBS:
361 is_ppp = true;
362 break;
363
364 case GRE_WCCP:
365 /* WCCP2 puts an extra 4 octets into the header, but uses the same
366 encapsulation type; if it looks as if the first octet of the packet
367 isn't the beginning of an IPv4 header, assume it's WCCP2. */
368 if ((tvb_get_uint8(tvb, offset + 2 + 2) & 0xF0) != 0x40) {
369 is_wccp2 = true;
370 }
371 break;
372 }
373
374 /* Per README.developer, section 1.2, we must call subdissectors regardless
375 * of whether "tree" is NULL or not. That is done below using
376 * call_dissector(), but since the next_tvb must begin at the correct offset,
377 * it's easier and more readable to always enter this block in order to
378 * compute the correct offset to pass to tvb_new_subset_remaining().
379 */
380 if (1) {
381 ti = proto_tree_add_protocol_format(tree, proto_gre, tvb, offset, -1, "Generic Routing Encapsulation (%s)",
382 val_to_str(type, gre_typevals, "0x%04X - unknown"));
383 gre_tree = proto_item_add_subtree(ti, ett_gre);
384
385
386 it_flags = proto_tree_add_item(gre_tree, hf_gre_flags_and_version, tvb, offset, 2, ENC_BIG_ENDIAN);
387 fv_tree = proto_item_add_subtree(it_flags, ett_gre_flags);
388
389 proto_tree_add_item(fv_tree, hf_gre_flags_checksum, tvb, offset, 2, ENC_BIG_ENDIAN);
390
391 proto_tree_add_item(fv_tree, hf_gre_flags_routing, tvb, offset, 2, ENC_BIG_ENDIAN);
392
393 proto_tree_add_item(fv_tree, hf_gre_flags_key, tvb, offset, 2, ENC_BIG_ENDIAN);
394
395 proto_tree_add_item(fv_tree, hf_gre_flags_sequence_number, tvb, offset, 2, ENC_BIG_ENDIAN);
396
397 proto_tree_add_item(fv_tree, hf_gre_flags_strict_source_route, tvb, offset, 2, ENC_BIG_ENDIAN);
398
399 proto_tree_add_item(fv_tree, hf_gre_flags_recursion_control, tvb, offset, 2, ENC_BIG_ENDIAN);
400
401 /* RFC2637 Section 4.1 : Enhanced GRE Header */
402 if (is_ppp) {
403 proto_tree_add_item(fv_tree, hf_gre_flags_ack, tvb, offset, 2, ENC_BIG_ENDIAN);
404
405 proto_tree_add_item(fv_tree, hf_gre_flags_reserved_ppp, tvb, offset, 2, ENC_BIG_ENDIAN);
406 }
407 else {
408 proto_tree_add_item(fv_tree, hf_gre_flags_reserved, tvb, offset, 2, ENC_BIG_ENDIAN);
409 }
410
411 proto_tree_add_item(fv_tree, hf_gre_flags_version, tvb, offset, 2, ENC_BIG_ENDIAN);
412
413 offset += 2;
414
415 proto_tree_add_item(gre_tree, hf_gre_proto, tvb, offset, 2, ENC_BIG_ENDIAN);
416 offset += 2;
417
418 if (gre_hdr_info.flags_and_ver & GRE_CHECKSUM || gre_hdr_info.flags_and_ver & GRE_ROUTING) {
419 unsigned length, reported_length;
420 vec_t cksum_vec[1];
421
422 /* Checksum check !... */
423 length = tvb_captured_length(tvb);
424 reported_length = tvb_reported_length(tvb);
425 /* The Checksum Present bit is set, and the packet isn't part of a
426 fragmented datagram and isn't truncated, so we can checksum it. */
427 if ((gre_hdr_info.flags_and_ver & GRE_CHECKSUM) && !pinfo->fragmented && length >= reported_length) {
428 SET_CKSUM_VEC_TVB(cksum_vec[0], tvb, 0, reported_length);
429 proto_tree_add_checksum(gre_tree, tvb, offset, hf_gre_checksum, hf_gre_checksum_status, &ei_gre_checksum_incorrect, pinfo, in_cksum(cksum_vec, 1),
430 ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY|PROTO_CHECKSUM_IN_CKSUM);
431 } else {
432 proto_tree_add_checksum(gre_tree, tvb, offset, hf_gre_checksum, hf_gre_checksum_status, &ei_gre_checksum_incorrect, pinfo, 0,
433 ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
434 }
435 offset += 2;
436
437 proto_tree_add_item(gre_tree, hf_gre_offset, tvb, offset, 2, ENC_BIG_ENDIAN);
438 offset += 2;
439 }
440
441 if (gre_hdr_info.flags_and_ver & GRE_KEY) {
442 /* RFC2637 Section 4.1 : Enhanced GRE Header */
443 if (is_ppp && type!=ETHERTYPE_CDMA2000_A10_UBS) {
444
445 proto_tree_add_item(gre_tree, hf_gre_key_payload_length, tvb, offset, 2, ENC_BIG_ENDIAN);
446 offset += 2;
447
448 proto_tree_add_item(gre_tree, hf_gre_key_call_id, tvb, offset, 2, ENC_BIG_ENDIAN);
449 offset += 2;
450 }
451 else {
452 proto_tree_add_item_ret_uint(gre_tree, hf_gre_key, tvb, offset, 4, ENC_BIG_ENDIAN, &gre_hdr_info.key);
453 offset += 4;
454 }
455 }
456 if (gre_hdr_info.flags_and_ver & GRE_SEQUENCE) {
457
458 proto_tree_add_item(gre_tree, hf_gre_sequence_number , tvb, offset, 4, ENC_BIG_ENDIAN);
459 offset += 4;
460 }
461 if (is_ppp && (gre_hdr_info.flags_and_ver & GRE_ACK)) {
462
463 proto_tree_add_item(gre_tree, hf_gre_ack_number , tvb, offset, 4, ENC_BIG_ENDIAN);
464 offset += 4;
465 }
466 if (gre_hdr_info.flags_and_ver & GRE_ROUTING) {
467 proto_item *it_routing;
468 proto_tree *r_tree;
469 for (;;) {
470
471 it_routing = proto_tree_add_item(gre_tree, hf_gre_routing, tvb, offset, -1, ENC_NA);
472 r_tree = proto_item_add_subtree(ti, ett_gre_routing);
473
474 sre_af = tvb_get_ntohs(tvb, offset);
475 proto_tree_add_item(r_tree, hf_gre_routing_address_family , tvb, offset, 2, ENC_BIG_ENDIAN);
476 offset += 2;
477
478 proto_tree_add_item(r_tree, hf_gre_routing_sre_offset , tvb, offset, 1, ENC_BIG_ENDIAN);
479 offset += 1;
480
481 sre_length = tvb_get_uint8(tvb, offset);
482 proto_tree_add_item(r_tree, hf_gre_routing_sre_length , tvb, offset, 1, ENC_BIG_ENDIAN);
483 offset += 1;
484
485 proto_item_set_len(it_routing, 2 + 1 +1 + sre_length);
486 if (sre_af == 0 && sre_length == 0)
487 break;
488
489 proto_tree_add_item(r_tree, hf_gre_routing_information , tvb, offset, sre_length, ENC_NA);
490 offset += sre_length;
491 }
492 }
493
494 if (type == GRE_WCCP && is_wccp2) {
495 dissect_gre_wccp2_redirect_header(tvb, offset, gre_tree);
496 offset += 4;
497 }
498 if (type == ETHERTYPE_3GPP2) {
499 offset = dissect_gre_3gpp2_attribs(tvb, offset, gre_tree);
500 }
501
502 proto_item_set_len(ti, offset);
503
504 /* If the S bit is not set, this packet might not have a payload, so
505 check whether there's any data left, first.
506
507 XXX - the S bit isn't in RFC 2784, which deprecates that bit
508 and some other bits in RFC 1701 and says that they should be
509 zero for RFC 2784-compliant GRE; as such, the absence of the
510 S bit doesn't necessarily mean there's no payload. */
511 if (!(gre_hdr_info.flags_and_ver & GRE_SEQUENCE)) {
512 if (tvb_reported_length_remaining(tvb, offset) <= 0)
513 return offset; /* no payload */
514 }
515 next_tvb = tvb_new_subset_remaining(tvb, offset);
516 pinfo->flags.in_gre_pkt = true;
517 if (!dissector_try_uint_with_data(gre_dissector_table, type, next_tvb, pinfo, tree, true, &gre_hdr_info))
518 if (!dissector_try_payload_with_data(gre_subdissector_table, next_tvb, pinfo, tree, true, &gre_hdr_info)) {
519 call_data_dissector(next_tvb, pinfo, gre_tree);
520 }
521 }
522 return tvb_captured_length(tvb);
523 }
524
525 static void
526 gre_prompt(packet_info *pinfo _U_, char* result)
527 {
528 snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "GRE proto as");
529 }
530
531 void
532 proto_register_gre(void)
533 {
534 static hf_register_info hf[] = {
535 { &hf_gre_proto,
536 { "Protocol Type", "gre.proto",
537 FT_UINT16, BASE_HEX, VALS(gre_typevals), 0x0,
538 "The protocol that is GRE encapsulated", HFILL }
539 },
540 { &hf_gre_flags_and_version,
541 { "Flags and Version", "gre.flags_and_version",
542 FT_UINT16, BASE_HEX, NULL, 0x0,
543 "The GRE flags are encoded in the first two octets", HFILL }
544 },
545 { &hf_gre_flags_checksum,
546 { "Checksum Bit", "gre.flags.checksum",
547 FT_BOOLEAN, 16, TFS(&tfs_yes_no), GRE_CHECKSUM,
548 "Indicates if the Checksum field is present", HFILL }
549 },
550 { &hf_gre_flags_routing,
551 { "Routing Bit", "gre.flags.routing",
552 FT_BOOLEAN, 16, TFS(&tfs_yes_no), GRE_ROUTING,
553 "Indicates if the Routing and Checksum/Offset field are present", HFILL }
554 },
555 { &hf_gre_flags_key,
556 { "Key Bit", "gre.flags.key",
557 FT_BOOLEAN, 16, TFS(&tfs_yes_no), GRE_KEY,
558 "Indicates if the Key field is present", HFILL }
559 },
560 { &hf_gre_flags_sequence_number,
561 { "Sequence Number Bit", "gre.flags.sequence_number",
562 FT_BOOLEAN, 16, TFS(&tfs_yes_no), GRE_SEQUENCE,
563 "Indicates if the Sequence Number field is present", HFILL }
564 },
565 { &hf_gre_flags_strict_source_route,
566 { "Strict Source Route Bit", "gre.flags.strict_source_route",
567 FT_BOOLEAN, 16, TFS(&tfs_yes_no), GRE_STRICTSOURCE,
568 NULL, HFILL }
569 },
570 { &hf_gre_flags_recursion_control,
571 { "Recursion control", "gre.flags.recursion_control",
572 FT_UINT16, BASE_DEC, NULL, GRE_RECURSION,
573 NULL, HFILL }
574 },
575 { &hf_gre_flags_ack,
576 { "Acknowledgment", "gre.flags.ack",
577 FT_BOOLEAN, 16, TFS(&tfs_yes_no), GRE_ACK,
578 "Indicates if the packet contains an Acknowledgment Number to be used for acknowledging previously transmitted data", HFILL }
579 },
580 { &hf_gre_flags_reserved,
581 { "Flags (Reserved)", "gre.flags.reserved",
582 FT_UINT16, BASE_DEC, NULL, GRE_RESERVED,
583 NULL, HFILL }
584 },
585 { &hf_gre_flags_reserved_ppp,
586 { "Flags (Reserved)", "gre.flags.reserved",
587 FT_UINT16, BASE_DEC, NULL, GRE_RESERVED_PPP,
588 NULL, HFILL }
589 },
590 { &hf_gre_flags_version,
591 { "Version", "gre.flags.version",
592 FT_UINT16, BASE_DEC, VALS(gre_version), GRE_VERSION,
593 NULL, HFILL }
594 },
595 { &hf_gre_checksum,
596 { "Checksum", "gre.checksum",
597 FT_UINT16, BASE_HEX, NULL, 0x0,
598 "The Checksum field contains the IP (one's complement) checksum of the GRE header and the payload packet", HFILL }
599 },
600 { &hf_gre_checksum_status,
601 { "Checksum Status", "gre.checksum.status",
602 FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
603 NULL, HFILL }
604 },
605 { &hf_gre_offset,
606 { "Offset", "gre.offset",
607 FT_UINT16, BASE_DEC, NULL, 0x0,
608 "The offset field indicates the octet offset from the start of the Routing field to the first octet of the active Source Route Entry to be examined", HFILL }
609 },
610 { &hf_gre_key,
611 { "Key", "gre.key",
612 FT_UINT32, BASE_HEX, NULL, 0x0,
613 "The Key field contains a four octet number which was inserted by the encapsulator", HFILL }
614 },
615 { &hf_gre_key_payload_length,
616 { "Payload Length", "gre.key.payload_length",
617 FT_UINT16, BASE_DEC, NULL, 0x0,
618 "Size of the payload, not including the GRE header", HFILL }
619 },
620 { &hf_gre_key_call_id,
621 { "Call ID", "gre.key.call_id",
622 FT_UINT16, BASE_DEC, NULL, 0x0,
623 "Contains the Peer's Call ID for the session to which this packet belongs.", HFILL }
624 },
625 { &hf_gre_sequence_number,
626 { "Sequence Number", "gre.sequence_number",
627 FT_UINT32, BASE_DEC, NULL, 0x0,
628 "The Sequence Number field contains an unsigned 32 bit integer which is inserted by the encapsulator", HFILL }
629 },
630 { &hf_gre_ack_number,
631 { "Acknowledgment Number", "gre.ack_number",
632 FT_UINT32, BASE_DEC, NULL, 0x0,
633 "Contains the sequence number of the highest numbered GRE packet received by the sending peer for this user session", HFILL }
634 },
635 { &hf_gre_routing,
636 { "Routing", "gre.routing",
637 FT_NONE, BASE_NONE, NULL, 0x0,
638 "The Routing field is a list of Source Route Entries (SREs)", HFILL }
639 },
640 { &hf_gre_routing_address_family,
641 { "Address Family", "gre.routing.address_family",
642 FT_UINT16, BASE_DEC, NULL, 0x0,
643 "The Address Family field contains a two octet value which indicates the syntax and semantics of the Routing Information field", HFILL }
644 },
645 { &hf_gre_routing_sre_offset,
646 { "SRE Offset", "gre.routing.sre_offset",
647 FT_UINT8, BASE_DEC, NULL, 0x0,
648 "The Address Family field contains a two octet value which indicates the syntax and semantics of the Routing Information field", HFILL }
649 },
650 { &hf_gre_routing_sre_length,
651 { "SRE Length", "gre.routing.src_length",
652 FT_UINT8, BASE_DEC, NULL, 0x0,
653 "The SRE Length field contains the number of octets in the SRE", HFILL }
654 },
655 { &hf_gre_routing_information,
656 { "Routing Information", "gre.routing.information",
657 FT_BYTES, BASE_NONE, NULL, 0x0,
658 "The Routing Information field contains data which may be used in routing this packet", HFILL }
659 },
660 { &hf_gre_3gpp2_attrib,
661 { "3GPP2 Attributes", "gre.3gpp2_attrib",
662 FT_NONE, BASE_NONE, NULL, 0x0,
663 NULL, HFILL }
664 },
665 { &hf_gre_3gpp2_attrib_id,
666 { "Type", "gre.3gpp2_attrib_id",
667 FT_UINT8, BASE_HEX, VALS(gre_3gpp2_attrib_id_vals), 0x7f,
668 NULL, HFILL }
669 },
670 { &hf_gre_3gpp2_attrib_length,
671 { "Length", "gre.3gpp2_attrib_length",
672 FT_UINT8, BASE_HEX, NULL, 0x0,
673 NULL, HFILL }
674 },
675 { &hf_gre_3gpp2_sdi,
676 { "SDI/DOS", "gre.3gpp2_sdi",
677 FT_BOOLEAN, 16, TFS(&gre_3gpp2_sdi_val), 0x8000,
678 "Short Data Indicator(SDI)/Data Over Signaling (DOS)", HFILL }
679 },
680 { &hf_gre_3gpp2_fci,
681 { "Flow Control Indicator", "gre.3gpp2_fci",
682 FT_BOOLEAN, 16, TFS(&gre_3gpp2_fci_val), 0x8000,
683 NULL, HFILL }
684 },
685 { &hf_gre_3gpp2_di,
686 { "Duration Indicator", "gre.3gpp2_di",
687 FT_BOOLEAN, 16, TFS(&gre_3gpp2_di_val), 0x4000,
688 NULL, HFILL }
689 },
690 { &hf_gre_3gpp2_flow_disc,
691 { "Flow ID", "gre.ggp2_flow_disc",
692 FT_BYTES, BASE_NONE, NULL, 0x0,
693 NULL, HFILL }
694 },
695 { &hf_gre_3gpp2_seg,
696 { "Type", "gre.ggp2_3gpp2_seg",
697 FT_UINT16, BASE_HEX, VALS(gre_3gpp2_seg_vals), 0xc000,
698 NULL, HFILL }
699 },
700
701 { &hf_gre_wccp_redirect_header,
702 { "Redirect Header", "gre.wccp.redirect_header",
703 FT_NONE, BASE_NONE, NULL, 0x0,
704 NULL, HFILL }
705 },
706 { &hf_gre_wccp_dynamic_service,
707 { "Dynamic Service", "gre.wccp.dynamic_service",
708 FT_BOOLEAN, 8, TFS(&gre_wccp_dynamic_service_val), 0x01,
709 NULL, HFILL }
710 },
711 { &hf_gre_wccp_alternative_bucket_used,
712 { "Alternative bucket used", "gre.wccp.alternative_bucket_used",
713 FT_BOOLEAN, 8, TFS(&gre_wccp_alternative_bucket_used_val), 0x02,
714 NULL, HFILL }
715 },
716 { &hf_gre_wccp_redirect_header_valid,
717 { "WCCP Redirect header is valid", "gre.wccp.redirect_header_valid",
718 FT_BOOLEAN, 8, TFS(&gre_wccp_redirect_header_valid_val), 0x04,
719 NULL, HFILL }
720 },
721 { &hf_gre_wccp_service_id,
722 { "Service ID", "gre.wccp.service_id",
723 FT_UINT8, BASE_DEC, VALS(service_id_vals), 0x00,
724 "Service Group identifier", HFILL }
725 },
726 { &hf_gre_wccp_alternative_bucket,
727 { "Alternative Bucket", "gre.wccp.alternative_bucket",
728 FT_UINT8, BASE_DEC, NULL, 0x0,
729 "Alternative bucket index used to redirect the packet.", HFILL }
730 },
731 { &hf_gre_wccp_primary_bucket,
732 { "Primary Bucket", "gre.wccp.primary_bucket",
733 FT_UINT8, BASE_DEC, NULL, 0x0,
734 "Primary bucket index used to redirect the packet.", HFILL }
735 },
736 };
737 static int *ett[] = {
738 &ett_gre,
739 &ett_gre_flags,
740 &ett_gre_routing,
741 &ett_gre_wccp2_redirect_header,
742 &ett_3gpp2_attribs,
743 &ett_3gpp2_attr,
744 };
745
746
747 static ei_register_info ei[] = {
748 { &ei_gre_checksum_incorrect, { "gre.checksum.incorrect", PI_PROTOCOL, PI_WARN, "Incorrect GRE Checksum", EXPFILL }},
749 };
750
751 expert_module_t* expert_gre;
752
753 proto_gre = proto_register_protocol("Generic Routing Encapsulation",
754 "GRE", "gre");
755 gre_handle = register_dissector("gre", dissect_gre, proto_gre);
756 gre_cap_handle = register_capture_dissector("gre", capture_gre, proto_gre);
757 proto_register_field_array(proto_gre, hf, array_length(hf));
758 proto_register_subtree_array(ett, array_length(ett));
759 expert_gre = expert_register_protocol(proto_gre);
760 expert_register_field_array(expert_gre, ei, array_length(ei));
761
762 /*
763 * Dissector table.
764 *
765 * XXX - according to
766 *
767 * https://www.iana.org/assignments/gre-parameters/gre-parameters.xhtml#gre-parameters-1
768 *
769 * these are just Ethertypes; should we use "gre.proto" only for
770 * protocols *not* registered as Ethertypes, such as those listed
771 * in the table in "Current List of Protocol Types" in RFC 1701
772 * ("For historical reasons, a number of other values have been
773 * used for some protocols."), and for protocols encapsulated in GRE
774 * differently from the way they're encapsulated over LAN protocols
775 * (for example, Cisco MetaData), and if we don't get a match there,
776 * use the "ethertype" table?
777 *
778 * And should we also somehow do something similar for mapping values
779 * to strings, falling back on etype_vals?
780 */
781 gre_dissector_table = register_dissector_table("gre.proto",
782 "GRE protocol type", proto_gre, FT_UINT16, BASE_HEX);
783
784 gre_subdissector_table = register_decode_as_next_proto(proto_gre, "gre.subproto",
785 "GRE protocol type", gre_prompt);
786 }
787
788 void
789 proto_reg_handoff_gre(void)
790 {
791 dissector_add_uint("ip.proto", IP_PROTO_GRE, gre_handle);
792 dissector_add_uint("udp.port", GRE_IN_UDP_PORT, gre_handle);
793 capture_dissector_add_uint("ip.proto", IP_PROTO_GRE, gre_cap_handle);
794 }
795
796 /*
797 * Editor modelines - https://www.wireshark.org/tools/modelines.html
798 *
799 * Local variables:
800 * c-basic-offset: 4
801 * tab-width: 8
802 * indent-tabs-mode: nil
803 * End:
804 *
805 * vi: set shiftwidth=4 tabstop=8 expandtab:
806 * :indentSize=4:tabSize=8:noTabs=true:
807 */
Metzes wireshark repo