1 /* $OpenBSD: print-gre.c,v 1.6 2002/10/30 03:04:04 fgsch Exp $ */
4 * Copyright (c) 2002 Jason L. Wright (jason@thought.net)
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
20 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
25 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
29 /* \summary: Generic Routing Encapsulation (GRE) printer */
32 * netdissect printer for GRE - Generic Routing Encapsulation
33 * RFC1701 (GRE), RFC1702 (GRE IPv4), and RFC2637 (Enhanced GRE)
40 #include "netdissect-stdinc.h"
42 #include "netdissect.h"
43 #include "addrtostr.h"
45 #include "ethertype.h"
48 #define GRE_CP 0x8000 /* checksum present */
49 #define GRE_RP 0x4000 /* routing present */
50 #define GRE_KP 0x2000 /* key present */
51 #define GRE_SP 0x1000 /* sequence# present */
52 #define GRE_sP 0x0800 /* source routing */
53 #define GRE_AP 0x0080 /* acknowledgment# present */
55 static const struct tok gre_flag_values[] = {
56 { GRE_CP, "checksum present"},
57 { GRE_RP, "routing present"},
58 { GRE_KP, "key present"},
59 { GRE_SP, "sequence# present"},
60 { GRE_sP, "source routing present"},
61 { GRE_AP, "ack present"},
65 #define GRE_RECRS_MASK 0x0700 /* recursion count */
66 #define GRE_VERS_MASK 0x0007 /* protocol version */
68 /* source route entry types */
69 #define GRESRE_IP 0x0800 /* IP */
70 #define GRESRE_ASN 0xfffe /* ASN */
72 static void gre_print_0(netdissect_options *, const u_char *, u_int);
73 static void gre_print_1(netdissect_options *, const u_char *, u_int);
74 static int gre_sre_print(netdissect_options *, uint16_t, uint8_t, uint8_t, const u_char *, u_int);
75 static int gre_sre_ip_print(netdissect_options *, uint8_t, uint8_t, const u_char *, u_int);
76 static int gre_sre_asn_print(netdissect_options *, uint8_t, uint8_t, const u_char *, u_int);
79 gre_print(netdissect_options *ndo, const u_char *bp, u_int length)
81 u_int len = length, vers;
83 ndo->ndo_protocol = "gre";
87 vers = GET_BE_U_2(bp) & GRE_VERS_MASK;
88 ND_PRINT("GREv%u",vers);
92 gre_print_0(ndo, bp, len);
95 gre_print_1(ndo, bp, len);
98 ND_PRINT(" ERROR: unknown-version");
108 gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
111 uint16_t flags, prot;
113 /* 16 bits ND_TCHECKed in gre_print() */
114 flags = GET_BE_U_2(bp);
116 ND_PRINT(", Flags [%s]",
117 bittok2str(gre_flag_values,"none",flags));
125 prot = GET_BE_U_2(bp);
129 if ((flags & GRE_CP) | (flags & GRE_RP)) {
134 ND_PRINT(", sum 0x%x", GET_BE_U_2(bp));
141 ND_PRINT(", off 0x%x", GET_BE_U_2(bp));
146 if (flags & GRE_KP) {
150 ND_PRINT(", key=0x%x", GET_BE_U_4(bp));
155 if (flags & GRE_SP) {
159 ND_PRINT(", seq %u", GET_BE_U_4(bp));
164 if (flags & GRE_RP) {
174 sreoff = GET_U_1(bp + 2);
175 srelen = GET_U_1(bp + 3);
179 if (af == 0 && srelen == 0)
182 if (!gre_sre_print(ndo, af, sreoff, srelen, bp, len))
193 ND_PRINT(", proto %s (0x%04x)",
194 tok2str(ethertype_values,"unknown",prot), prot);
196 ND_PRINT(", length %u",length);
198 if (ndo->ndo_vflag < 1)
199 ND_PRINT(": "); /* put in a colon as protocol demarc */
201 ND_PRINT("\n\t"); /* if verbose go multiline */
205 ip_print(ndo, bp, len);
208 ip6_print(ndo, bp, len);
211 mpls_print(ndo, bp, len);
214 ipx_print(ndo, bp, len);
216 case ETHERTYPE_ATALK:
217 atalk_print(ndo, bp, len);
219 case ETHERTYPE_GRE_ISO:
220 isoclns_print(ndo, bp, len);
223 ether_print(ndo, bp, len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
226 ND_PRINT("gre-proto-0x%x", prot);
235 gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
238 uint16_t flags, prot;
240 /* 16 bits ND_TCHECKed in gre_print() */
241 flags = GET_BE_U_2(bp);
246 ND_PRINT(", Flags [%s]",
247 bittok2str(gre_flag_values,"none",flags));
252 prot = GET_BE_U_2(bp);
257 if (flags & GRE_KP) {
264 ND_PRINT(", call %u", k & 0xffff);
269 if (flags & GRE_SP) {
273 ND_PRINT(", seq %u", GET_BE_U_4(bp));
278 if (flags & GRE_AP) {
282 ND_PRINT(", ack %u", GET_BE_U_4(bp));
287 if ((flags & GRE_SP) == 0)
288 ND_PRINT(", no-payload");
291 ND_PRINT(", proto %s (0x%04x)",
292 tok2str(ethertype_values,"unknown",prot), prot);
294 ND_PRINT(", length %u",length);
296 if ((flags & GRE_SP) == 0)
299 if (ndo->ndo_vflag < 1)
300 ND_PRINT(": "); /* put in a colon as protocol demarc */
302 ND_PRINT("\n\t"); /* if verbose go multiline */
306 ppp_print(ndo, bp, len);
309 ND_PRINT("gre-proto-0x%x", prot);
319 gre_sre_print(netdissect_options *ndo, uint16_t af, uint8_t sreoff,
320 uint8_t srelen, const u_char *bp, u_int len)
326 ND_PRINT(", (rtaf=ip");
327 ret = gre_sre_ip_print(ndo, sreoff, srelen, bp, len);
331 ND_PRINT(", (rtaf=asn");
332 ret = gre_sre_asn_print(ndo, sreoff, srelen, bp, len);
336 ND_PRINT(", (rtaf=0x%x)", af);
343 gre_sre_ip_print(netdissect_options *ndo, uint8_t sreoff, uint8_t srelen,
344 const u_char *bp, u_int len)
346 const u_char *up = bp;
347 char buf[INET_ADDRSTRLEN];
350 ND_PRINT(", badoffset=%u", sreoff);
354 ND_PRINT(", badlength=%u", srelen);
357 if (sreoff >= srelen) {
358 ND_PRINT(", badoff/len=%u/%u", sreoff, srelen);
362 while (srelen != 0) {
367 addrtostr(bp, buf, sizeof(buf));
369 ((bp - up) == sreoff) ? "*" : "", buf);
381 gre_sre_asn_print(netdissect_options *ndo, uint8_t sreoff, uint8_t srelen,
382 const u_char *bp, u_int len)
384 const u_char *up = bp;
387 ND_PRINT(", badoffset=%u", sreoff);
391 ND_PRINT(", badlength=%u", srelen);
394 if (sreoff >= srelen) {
395 ND_PRINT(", badoff/len=%u/%u", sreoff, srelen);
399 while (srelen != 0) {
405 ((bp - up) == sreoff) ? "*" : "", GET_BE_U_2(bp));