| 1 | /* $OpenBSD: print-gre.c,v 1.6 2002/10/30 03:04:04 fgsch Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 2002 Jason L. Wright (jason@thought.net) |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * Redistribution and use in source and binary forms, with or without |
| 8 | * modification, are permitted provided that the following conditions |
| 9 | * are met: |
| 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. |
| 15 | * 3. All advertising materials mentioning features or use of this software |
| 16 | * must display the following acknowledgement: |
| 17 | * This product includes software developed by Jason L. Wright |
| 18 | * 4. The name of the author may not be used to endorse or promote products |
| 19 | * derived from this software without specific prior written permission. |
| 20 | * |
| 21 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 22 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| 23 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| 24 | * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, |
| 25 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 26 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| 27 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 29 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
| 30 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 31 | * POSSIBILITY OF SUCH DAMAGE. |
| 32 | */ |
| 33 | |
| 34 | /* |
| 35 | * tcpdump filter for GRE - Generic Routing Encapsulation |
| 36 | * RFC1701 (GRE), RFC1702 (GRE IPv4), and RFC2637 (Enhanced GRE) |
| 37 | */ |
| 38 | |
| 39 | #ifndef lint |
| 40 | static const char rcsid[] _U_ = |
| 41 | "@(#) $Header: /tcpdump/master/tcpdump/print-gre.c,v 1.28 2005/04/06 21:32:39 mcr Exp $ (LBL)"; |
| 42 | #endif |
| 43 | |
| 44 | #ifdef HAVE_CONFIG_H |
| 45 | #include "config.h" |
| 46 | #endif |
| 47 | |
| 48 | #include <tcpdump-stdinc.h> |
| 49 | |
| 50 | #include <stdio.h> |
| 51 | #include <string.h> |
| 52 | |
| 53 | #include "interface.h" |
| 54 | #include "addrtoname.h" |
| 55 | #include "extract.h" |
| 56 | |
| 57 | #include "ip.h" |
| 58 | #include "ethertype.h" |
| 59 | |
| 60 | #define GRE_CP 0x8000 /* checksum present */ |
| 61 | #define GRE_RP 0x4000 /* routing present */ |
| 62 | #define GRE_KP 0x2000 /* key present */ |
| 63 | #define GRE_SP 0x1000 /* sequence# present */ |
| 64 | #define GRE_sP 0x0800 /* source routing */ |
| 65 | #define GRE_RECRS 0x0700 /* recursion count */ |
| 66 | #define GRE_AP 0x0080 /* acknowledgment# present */ |
| 67 | |
| 68 | struct tok gre_flag_values[] = { |
| 69 | { GRE_CP, "checksum present"}, |
| 70 | { GRE_RP, "routing present"}, |
| 71 | { GRE_KP, "key present"}, |
| 72 | { GRE_SP, "sequence# present"}, |
| 73 | { GRE_sP, "source routing present"}, |
| 74 | { GRE_RECRS, "recursion count"}, |
| 75 | { GRE_AP, "ack present"}, |
| 76 | { 0, NULL } |
| 77 | }; |
| 78 | |
| 79 | #define GRE_VERS_MASK 0x0007 /* protocol version */ |
| 80 | |
| 81 | /* source route entry types */ |
| 82 | #define GRESRE_IP 0x0800 /* IP */ |
| 83 | #define GRESRE_ASN 0xfffe /* ASN */ |
| 84 | |
| 85 | void gre_print_0(const u_char *, u_int); |
| 86 | void gre_print_1(const u_char *, u_int); |
| 87 | void gre_sre_print(u_int16_t, u_int8_t, u_int8_t, const u_char *, u_int); |
| 88 | void gre_sre_ip_print(u_int8_t, u_int8_t, const u_char *, u_int); |
| 89 | void gre_sre_asn_print(u_int8_t, u_int8_t, const u_char *, u_int); |
| 90 | |
| 91 | void |
| 92 | gre_print(const u_char *bp, u_int length) |
| 93 | { |
| 94 | u_int len = length, vers; |
| 95 | |
| 96 | if (len < 2) { |
| 97 | printf("[|gre]"); |
| 98 | return; |
| 99 | } |
| 100 | vers = EXTRACT_16BITS(bp) & GRE_VERS_MASK; |
| 101 | printf("GREv%u",vers); |
| 102 | |
| 103 | switch(vers) { |
| 104 | case 0: |
| 105 | gre_print_0(bp, len); |
| 106 | break; |
| 107 | case 1: |
| 108 | gre_print_1(bp, len); |
| 109 | break; |
| 110 | default: |
| 111 | printf(" ERROR: unknown-version"); |
| 112 | break; |
| 113 | } |
| 114 | return; |
| 115 | |
| 116 | } |
| 117 | |
| 118 | void |
| 119 | gre_print_0(const u_char *bp, u_int length) |
| 120 | { |
| 121 | u_int len = length; |
| 122 | u_int16_t flags, prot; |
| 123 | |
| 124 | flags = EXTRACT_16BITS(bp); |
| 125 | if (vflag) |
| 126 | printf(", Flags [%s]", |
| 127 | bittok2str(gre_flag_values,"none",flags)); |
| 128 | |
| 129 | len -= 2; |
| 130 | bp += 2; |
| 131 | |
| 132 | if (len < 2) |
| 133 | goto trunc; |
| 134 | prot = EXTRACT_16BITS(bp); |
| 135 | len -= 2; |
| 136 | bp += 2; |
| 137 | |
| 138 | if ((flags & GRE_CP) | (flags & GRE_RP)) { |
| 139 | if (len < 2) |
| 140 | goto trunc; |
| 141 | if (vflag) |
| 142 | printf(", sum 0x%x", EXTRACT_16BITS(bp)); |
| 143 | bp += 2; |
| 144 | len -= 2; |
| 145 | |
| 146 | if (len < 2) |
| 147 | goto trunc; |
| 148 | printf(", off 0x%x", EXTRACT_16BITS(bp)); |
| 149 | bp += 2; |
| 150 | len -= 2; |
| 151 | } |
| 152 | |
| 153 | if (flags & GRE_KP) { |
| 154 | if (len < 4) |
| 155 | goto trunc; |
| 156 | printf(", key=0x%x", EXTRACT_32BITS(bp)); |
| 157 | bp += 4; |
| 158 | len -= 4; |
| 159 | } |
| 160 | |
| 161 | if (flags & GRE_SP) { |
| 162 | if (len < 4) |
| 163 | goto trunc; |
| 164 | printf(", seq %u", EXTRACT_32BITS(bp)); |
| 165 | bp += 4; |
| 166 | len -= 4; |
| 167 | } |
| 168 | |
| 169 | if (flags & GRE_RP) { |
| 170 | for (;;) { |
| 171 | u_int16_t af; |
| 172 | u_int8_t sreoff; |
| 173 | u_int8_t srelen; |
| 174 | |
| 175 | if (len < 4) |
| 176 | goto trunc; |
| 177 | af = EXTRACT_16BITS(bp); |
| 178 | sreoff = *(bp + 2); |
| 179 | srelen = *(bp + 3); |
| 180 | bp += 4; |
| 181 | len -= 4; |
| 182 | |
| 183 | if (af == 0 && srelen == 0) |
| 184 | break; |
| 185 | |
| 186 | gre_sre_print(af, sreoff, srelen, bp, len); |
| 187 | |
| 188 | if (len < srelen) |
| 189 | goto trunc; |
| 190 | bp += srelen; |
| 191 | len -= srelen; |
| 192 | } |
| 193 | } |
| 194 | |
| 195 | if (eflag) |
| 196 | printf(", proto %s (0x%04x)", |
| 197 | tok2str(ethertype_values,"unknown",prot), |
| 198 | prot); |
| 199 | |
| 200 | printf(", length %u",length); |
| 201 | |
| 202 | if (vflag < 1) |
| 203 | printf(": "); /* put in a colon as protocol demarc */ |
| 204 | else |
| 205 | printf("\n\t"); /* if verbose go multiline */ |
| 206 | |
| 207 | switch (prot) { |
| 208 | case ETHERTYPE_IP: |
| 209 | ip_print(gndo, bp, len); |
| 210 | break; |
| 211 | #ifdef INET6 |
| 212 | case ETHERTYPE_IPV6: |
| 213 | ip6_print(bp, len); |
| 214 | break; |
| 215 | #endif |
| 216 | case ETHERTYPE_MPLS: |
| 217 | mpls_print(bp, len); |
| 218 | break; |
| 219 | case ETHERTYPE_IPX: |
| 220 | ipx_print(bp, len); |
| 221 | break; |
| 222 | case ETHERTYPE_ATALK: |
| 223 | atalk_print(bp, len); |
| 224 | break; |
| 225 | case ETHERTYPE_GRE_ISO: |
| 226 | isoclns_print(bp, len, len); |
| 227 | break; |
| 228 | default: |
| 229 | printf("gre-proto-0x%x", prot); |
| 230 | } |
| 231 | return; |
| 232 | |
| 233 | trunc: |
| 234 | printf("[|gre]"); |
| 235 | } |
| 236 | |
| 237 | void |
| 238 | gre_print_1(const u_char *bp, u_int length) |
| 239 | { |
| 240 | u_int len = length; |
| 241 | u_int16_t flags, prot; |
| 242 | |
| 243 | flags = EXTRACT_16BITS(bp); |
| 244 | len -= 2; |
| 245 | bp += 2; |
| 246 | |
| 247 | if (vflag) |
| 248 | printf(", Flags [%s]", |
| 249 | bittok2str(gre_flag_values,"none",flags)); |
| 250 | |
| 251 | if (len < 2) |
| 252 | goto trunc; |
| 253 | prot = EXTRACT_16BITS(bp); |
| 254 | len -= 2; |
| 255 | bp += 2; |
| 256 | |
| 257 | |
| 258 | if (flags & GRE_KP) { |
| 259 | u_int32_t k; |
| 260 | |
| 261 | if (len < 4) |
| 262 | goto trunc; |
| 263 | k = EXTRACT_32BITS(bp); |
| 264 | printf(", call %d", k & 0xffff); |
| 265 | len -= 4; |
| 266 | bp += 4; |
| 267 | } |
| 268 | |
| 269 | if (flags & GRE_SP) { |
| 270 | if (len < 4) |
| 271 | goto trunc; |
| 272 | printf(", seq %u", EXTRACT_32BITS(bp)); |
| 273 | bp += 4; |
| 274 | len -= 4; |
| 275 | } |
| 276 | |
| 277 | if (flags & GRE_AP) { |
| 278 | if (len < 4) |
| 279 | goto trunc; |
| 280 | printf(", ack %u", EXTRACT_32BITS(bp)); |
| 281 | bp += 4; |
| 282 | len -= 4; |
| 283 | } |
| 284 | |
| 285 | if ((flags & GRE_SP) == 0) |
| 286 | printf(", no-payload"); |
| 287 | |
| 288 | if (eflag) |
| 289 | printf(", proto %s (0x%04x)", |
| 290 | tok2str(ethertype_values,"unknown",prot), |
| 291 | prot); |
| 292 | |
| 293 | printf(", length %u",length); |
| 294 | |
| 295 | if ((flags & GRE_SP) == 0) |
| 296 | return; |
| 297 | |
| 298 | if (vflag < 1) |
| 299 | printf(": "); /* put in a colon as protocol demarc */ |
| 300 | else |
| 301 | printf("\n\t"); /* if verbose go multiline */ |
| 302 | |
| 303 | switch (prot) { |
| 304 | case ETHERTYPE_PPP: |
| 305 | ppp_print(bp, len); |
| 306 | break; |
| 307 | default: |
| 308 | printf("gre-proto-0x%x", prot); |
| 309 | break; |
| 310 | } |
| 311 | return; |
| 312 | |
| 313 | trunc: |
| 314 | printf("[|gre]"); |
| 315 | } |
| 316 | |
| 317 | void |
| 318 | gre_sre_print(u_int16_t af, u_int8_t sreoff, u_int8_t srelen, |
| 319 | const u_char *bp, u_int len) |
| 320 | { |
| 321 | switch (af) { |
| 322 | case GRESRE_IP: |
| 323 | printf(", (rtaf=ip"); |
| 324 | gre_sre_ip_print(sreoff, srelen, bp, len); |
| 325 | printf(") "); |
| 326 | break; |
| 327 | case GRESRE_ASN: |
| 328 | printf(", (rtaf=asn"); |
| 329 | gre_sre_asn_print(sreoff, srelen, bp, len); |
| 330 | printf(") "); |
| 331 | break; |
| 332 | default: |
| 333 | printf(", (rtaf=0x%x) ", af); |
| 334 | } |
| 335 | } |
| 336 | void |
| 337 | gre_sre_ip_print(u_int8_t sreoff, u_int8_t srelen, const u_char *bp, u_int len) |
| 338 | { |
| 339 | struct in_addr a; |
| 340 | const u_char *up = bp; |
| 341 | |
| 342 | if (sreoff & 3) { |
| 343 | printf(", badoffset=%u", sreoff); |
| 344 | return; |
| 345 | } |
| 346 | if (srelen & 3) { |
| 347 | printf(", badlength=%u", srelen); |
| 348 | return; |
| 349 | } |
| 350 | if (sreoff >= srelen) { |
| 351 | printf(", badoff/len=%u/%u", sreoff, srelen); |
| 352 | return; |
| 353 | } |
| 354 | |
| 355 | for (;;) { |
| 356 | if (len < 4 || srelen == 0) |
| 357 | return; |
| 358 | |
| 359 | memcpy(&a, bp, sizeof(a)); |
| 360 | printf(" %s%s", |
| 361 | ((bp - up) == sreoff) ? "*" : "", |
| 362 | inet_ntoa(a)); |
| 363 | |
| 364 | bp += 4; |
| 365 | len -= 4; |
| 366 | srelen -= 4; |
| 367 | } |
| 368 | } |
| 369 | |
| 370 | void |
| 371 | gre_sre_asn_print(u_int8_t sreoff, u_int8_t srelen, const u_char *bp, u_int len) |
| 372 | { |
| 373 | const u_char *up = bp; |
| 374 | |
| 375 | if (sreoff & 1) { |
| 376 | printf(", badoffset=%u", sreoff); |
| 377 | return; |
| 378 | } |
| 379 | if (srelen & 1) { |
| 380 | printf(", badlength=%u", srelen); |
| 381 | return; |
| 382 | } |
| 383 | if (sreoff >= srelen) { |
| 384 | printf(", badoff/len=%u/%u", sreoff, srelen); |
| 385 | return; |
| 386 | } |
| 387 | |
| 388 | for (;;) { |
| 389 | if (len < 2 || srelen == 0) |
| 390 | return; |
| 391 | |
| 392 | printf(" %s%x", |
| 393 | ((bp - up) == sreoff) ? "*" : "", |
| 394 | EXTRACT_16BITS(bp)); |
| 395 | |
| 396 | bp += 2; |
| 397 | len -= 2; |
| 398 | srelen -= 2; |
| 399 | } |
| 400 | } |