1 /* 2 * Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 * 21 * Code by Matt Thomas, Digital Equipment Corporation 22 * with an awful lot of hacking by Jeffrey Mogul, DECWRL 23 */ 24 25 #include <sys/cdefs.h> 26 #ifndef lint 27 __RCSID("$NetBSD: print-llc.c,v 1.10 2023/08/17 20:19:40 christos Exp $"); 28 #endif 29 30 /* \summary: IEEE 802.2 LLC printer */ 31 32 #ifdef HAVE_CONFIG_H 33 #include <config.h> 34 #endif 35 36 #include "netdissect-stdinc.h" 37 38 #include "netdissect.h" 39 #include "addrtoname.h" 40 #include "extract.h" 41 42 #include "llc.h" 43 #include "ethertype.h" 44 #include "oui.h" 45 46 static const struct tok llc_values[] = { 47 { LLCSAP_NULL, "Null" }, 48 { LLCSAP_GLOBAL, "Global" }, 49 { LLCSAP_8021B_I, "802.1B I" }, 50 { LLCSAP_8021B_G, "802.1B G" }, 51 { LLCSAP_IP, "IP" }, 52 { LLCSAP_SNA, "SNA" }, 53 { LLCSAP_PROWAYNM, "ProWay NM" }, 54 { LLCSAP_8021D, "STP" }, 55 { LLCSAP_RS511, "RS511" }, 56 { LLCSAP_ISO8208, "ISO8208" }, 57 { LLCSAP_PROWAY, "ProWay" }, 58 { LLCSAP_SNAP, "SNAP" }, 59 { LLCSAP_IPX, "IPX" }, 60 { LLCSAP_NETBEUI, "NetBeui" }, 61 { LLCSAP_ISONS, "OSI" }, 62 { 0, NULL }, 63 }; 64 65 static const struct tok llc_cmd_values[] = { 66 { LLC_UI, "ui" }, 67 { LLC_TEST, "test" }, 68 { LLC_XID, "xid" }, 69 { LLC_UA, "ua" }, 70 { LLC_DISC, "disc" }, 71 { LLC_DM, "dm" }, 72 { LLC_SABME, "sabme" }, 73 { LLC_FRMR, "frmr" }, 74 { 0, NULL } 75 }; 76 77 static const struct tok llc_flag_values[] = { 78 { 0, "Command" }, 79 { LLC_GSAP, "Response" }, 80 { LLC_U_POLL, "Poll" }, 81 { LLC_GSAP|LLC_U_POLL, "Final" }, 82 { LLC_IS_POLL, "Poll" }, 83 { LLC_GSAP|LLC_IS_POLL, "Final" }, 84 { 0, NULL } 85 }; 86 87 88 static const struct tok llc_ig_flag_values[] = { 89 { 0, "Individual" }, 90 { LLC_IG, "Group" }, 91 { 0, NULL } 92 }; 93 94 95 static const struct tok llc_supervisory_values[] = { 96 { 0, "Receiver Ready" }, 97 { 1, "Receiver not Ready" }, 98 { 2, "Reject" }, 99 { 0, NULL } 100 }; 101 102 103 static const struct tok cisco_values[] = { 104 { PID_CISCO_CDP, "CDP" }, 105 { PID_CISCO_VTP, "VTP" }, 106 { PID_CISCO_DTP, "DTP" }, 107 { PID_CISCO_UDLD, "UDLD" }, 108 { PID_CISCO_PVST, "PVST" }, 109 { PID_CISCO_VLANBRIDGE, "VLAN Bridge" }, 110 { 0, NULL } 111 }; 112 113 static const struct tok bridged_values[] = { 114 { PID_RFC2684_ETH_FCS, "Ethernet + FCS" }, 115 { PID_RFC2684_ETH_NOFCS, "Ethernet w/o FCS" }, 116 { PID_RFC2684_802_4_FCS, "802.4 + FCS" }, 117 { PID_RFC2684_802_4_NOFCS, "802.4 w/o FCS" }, 118 { PID_RFC2684_802_5_FCS, "Token Ring + FCS" }, 119 { PID_RFC2684_802_5_NOFCS, "Token Ring w/o FCS" }, 120 { PID_RFC2684_FDDI_FCS, "FDDI + FCS" }, 121 { PID_RFC2684_FDDI_NOFCS, "FDDI w/o FCS" }, 122 { PID_RFC2684_802_6_FCS, "802.6 + FCS" }, 123 { PID_RFC2684_802_6_NOFCS, "802.6 w/o FCS" }, 124 { PID_RFC2684_BPDU, "BPDU" }, 125 { 0, NULL }, 126 }; 127 128 static const struct tok null_values[] = { 129 { 0, NULL } 130 }; 131 132 struct oui_tok { 133 uint32_t oui; 134 const struct tok *tok; 135 }; 136 137 static const struct oui_tok oui_to_tok[] = { 138 { OUI_ENCAP_ETHER, ethertype_values }, 139 { OUI_CISCO_90, ethertype_values }, /* uses some Ethertype values */ 140 { OUI_APPLETALK, ethertype_values }, /* uses some Ethertype values */ 141 { OUI_CISCO, cisco_values }, 142 { OUI_RFC2684, bridged_values }, /* bridged, RFC 2427 FR or RFC 2864 ATM */ 143 { 0, NULL } 144 }; 145 146 /* 147 * If we printed information about the payload, returns the length of the LLC 148 * header, plus the length of any SNAP header following it. 149 * 150 * Otherwise (for example, if the packet has unknown SAPs or has a SNAP 151 * header with an unknown OUI/PID combination), returns the *negative* 152 * of that value. 153 */ 154 int 155 llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen, 156 const struct lladdr_info *src, const struct lladdr_info *dst) 157 { 158 uint8_t dsap_field, dsap, ssap_field, ssap; 159 uint16_t control; 160 int hdrlen; 161 int is_u; 162 163 ndo->ndo_protocol = "llc"; 164 if (caplen < 3) { 165 nd_print_trunc(ndo); 166 ND_DEFAULTPRINT((const u_char *)p, caplen); 167 return (caplen); 168 } 169 if (length < 3) { 170 nd_print_trunc(ndo); 171 ND_DEFAULTPRINT((const u_char *)p, caplen); 172 return (length); 173 } 174 175 dsap_field = GET_U_1(p); 176 ssap_field = GET_U_1(p + 1); 177 178 /* 179 * OK, what type of LLC frame is this? The length 180 * of the control field depends on that - I frames 181 * have a two-byte control field, and U frames have 182 * a one-byte control field. 183 */ 184 control = GET_U_1(p + 2); 185 if ((control & LLC_U_FMT) == LLC_U_FMT) { 186 /* 187 * U frame. 188 */ 189 is_u = 1; 190 hdrlen = 3; /* DSAP, SSAP, 1-byte control field */ 191 } else { 192 /* 193 * The control field in I and S frames is 194 * 2 bytes... 195 */ 196 if (caplen < 4) { 197 nd_print_trunc(ndo); 198 ND_DEFAULTPRINT((const u_char *)p, caplen); 199 return (caplen); 200 } 201 if (length < 4) { 202 nd_print_trunc(ndo); 203 ND_DEFAULTPRINT((const u_char *)p, caplen); 204 return (length); 205 } 206 207 /* 208 * ...and is little-endian. 209 */ 210 control = GET_LE_U_2(p + 2); 211 is_u = 0; 212 hdrlen = 4; /* DSAP, SSAP, 2-byte control field */ 213 } 214 215 if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) { 216 /* 217 * This is an Ethernet_802.3 IPX frame; it has an 218 * 802.3 header (i.e., an Ethernet header where the 219 * type/length field is <= MAX_ETHERNET_LENGTH_VAL, 220 * i.e. it's a length field, not a type field), but 221 * has no 802.2 header - the IPX packet starts right 222 * after the Ethernet header, with a signature of two 223 * bytes of 0xFF (which is LLCSAP_GLOBAL). 224 * 225 * (It might also have been an Ethernet_802.3 IPX at 226 * one time, but got bridged onto another network, 227 * such as an 802.11 network; this has appeared in at 228 * least one capture file.) 229 */ 230 231 if (ndo->ndo_eflag) 232 ND_PRINT("IPX 802.3: "); 233 234 ipx_print(ndo, p, length); 235 return (0); /* no LLC header */ 236 } 237 238 dsap = dsap_field & ~LLC_IG; 239 ssap = ssap_field & ~LLC_GSAP; 240 241 if (ndo->ndo_eflag) { 242 ND_PRINT("LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s", 243 tok2str(llc_values, "Unknown", dsap), 244 dsap, 245 tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG), 246 tok2str(llc_values, "Unknown", ssap), 247 ssap, 248 tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP)); 249 250 if (is_u) { 251 ND_PRINT(", ctrl 0x%02x: ", control); 252 } else { 253 ND_PRINT(", ctrl 0x%04x: ", control); 254 } 255 } 256 257 /* 258 * Skip LLC header. 259 */ 260 p += hdrlen; 261 length -= hdrlen; 262 caplen -= hdrlen; 263 264 if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP 265 && control == LLC_UI) { 266 /* 267 * XXX - what *is* the right bridge pad value here? 268 * Does anybody ever bridge one form of LAN traffic 269 * over a networking type that uses 802.2 LLC? 270 */ 271 if (!snap_print(ndo, p, length, caplen, src, dst, 2)) { 272 /* 273 * Unknown packet type; tell our caller, by 274 * returning a negative value, so they 275 * can print the raw packet. 276 */ 277 return (-(hdrlen + 5)); /* include LLC and SNAP header */ 278 } else 279 return (hdrlen + 5); /* include LLC and SNAP header */ 280 } 281 282 if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D && 283 control == LLC_UI) { 284 stp_print(ndo, p, length); 285 return (hdrlen); 286 } 287 288 if (ssap == LLCSAP_IP && dsap == LLCSAP_IP && 289 control == LLC_UI) { 290 /* 291 * This is an RFC 948-style IP packet, with 292 * an 802.3 header and an 802.2 LLC header 293 * with the source and destination SAPs being 294 * the IP SAP. 295 */ 296 ip_print(ndo, p, length); 297 return (hdrlen); 298 } 299 300 if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX && 301 control == LLC_UI) { 302 /* 303 * This is an Ethernet_802.2 IPX frame, with an 802.3 304 * header and an 802.2 LLC header with the source and 305 * destination SAPs being the IPX SAP. 306 */ 307 if (ndo->ndo_eflag) 308 ND_PRINT("IPX 802.2: "); 309 310 ipx_print(ndo, p, length); 311 return (hdrlen); 312 } 313 314 #ifdef ENABLE_SMB 315 if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI 316 && (!(control & LLC_S_FMT) || control == LLC_U_FMT)) { 317 /* 318 * we don't actually have a full netbeui parser yet, but the 319 * smb parser can handle many smb-in-netbeui packets, which 320 * is very useful, so we call that 321 * 322 * We don't call it for S frames, however, just I frames 323 * (which are frames that don't have the low-order bit, 324 * LLC_S_FMT, set in the first byte of the control field) 325 * and UI frames (whose control field is just 3, LLC_U_FMT). 326 */ 327 netbeui_print(ndo, control, p, length); 328 return (hdrlen); 329 } 330 #endif 331 if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS 332 && control == LLC_UI) { 333 isoclns_print(ndo, p, length); 334 return (hdrlen); 335 } 336 337 if (!ndo->ndo_eflag) { 338 if (ssap == dsap) { 339 if (src == NULL || dst == NULL) 340 ND_PRINT("%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)); 341 else 342 ND_PRINT("%s > %s %s ", 343 (src->addr_string)(ndo, src->addr), 344 (dst->addr_string)(ndo, dst->addr), 345 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)); 346 } else { 347 if (src == NULL || dst == NULL) 348 ND_PRINT("%s > %s ", 349 tok2str(llc_values, "Unknown SSAP 0x%02x", ssap), 350 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)); 351 else 352 ND_PRINT("%s %s > %s %s ", 353 (src->addr_string)(ndo, src->addr), 354 tok2str(llc_values, "Unknown SSAP 0x%02x", ssap), 355 (dst->addr_string)(ndo, dst->addr), 356 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)); 357 } 358 } 359 360 if (is_u) { 361 ND_PRINT("Unnumbered, %s, Flags [%s], length %u", 362 tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)), 363 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)), 364 length + hdrlen); 365 366 if ((control & ~LLC_U_POLL) == LLC_XID) { 367 if (length == 0) { 368 /* 369 * XID with no payload. 370 * This could, for example, be an SNA 371 * "short form" XID. 372 */ 373 return (hdrlen); 374 } 375 if (caplen < 1) { 376 nd_print_trunc(ndo); 377 if (caplen > 0) 378 ND_DEFAULTPRINT((const u_char *)p, caplen); 379 return (hdrlen); 380 } 381 if (GET_U_1(p) == LLC_XID_FI) { 382 if (caplen < 3 || length < 3) { 383 nd_print_trunc(ndo); 384 if (caplen > 0) 385 ND_DEFAULTPRINT((const u_char *)p, caplen); 386 } else 387 ND_PRINT(": %02x %02x", 388 GET_U_1(p + 1), 389 GET_U_1(p + 2)); 390 return (hdrlen); 391 } 392 } 393 } else { 394 if ((control & LLC_S_FMT) == LLC_S_FMT) { 395 ND_PRINT("Supervisory, %s, rcv seq %u, Flags [%s], length %u", 396 tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)), 397 LLC_IS_NR(control), 398 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)), 399 length + hdrlen); 400 return (hdrlen); /* no payload to print */ 401 } else { 402 ND_PRINT("Information, send seq %u, rcv seq %u, Flags [%s], length %u", 403 LLC_I_NS(control), 404 LLC_IS_NR(control), 405 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)), 406 length + hdrlen); 407 } 408 } 409 return (-hdrlen); 410 } 411 412 static const struct tok * 413 oui_to_struct_tok(uint32_t orgcode) 414 { 415 const struct tok *tok = null_values; 416 const struct oui_tok *otp; 417 418 for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) { 419 if (otp->oui == orgcode) { 420 tok = otp->tok; 421 break; 422 } 423 } 424 return (tok); 425 } 426 427 int 428 snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen, 429 const struct lladdr_info *src, const struct lladdr_info *dst, 430 u_int bridge_pad) 431 { 432 uint32_t orgcode; 433 u_short et; 434 int ret; 435 436 ndo->ndo_protocol = "snap"; 437 ND_TCHECK_5(p); 438 if (caplen < 5 || length < 5) 439 goto trunc; 440 orgcode = GET_BE_U_3(p); 441 et = GET_BE_U_2(p + 3); 442 443 if (ndo->ndo_eflag) { 444 /* 445 * Somebody's already printed the MAC addresses, if there 446 * are any, so just print the SNAP header, not the MAC 447 * addresses. 448 */ 449 ND_PRINT("oui %s (0x%06x), %s %s (0x%04x), length %u: ", 450 tok2str(oui_values, "Unknown", orgcode), 451 orgcode, 452 (orgcode == 0x000000 ? "ethertype" : "pid"), 453 tok2str(oui_to_struct_tok(orgcode), "Unknown", et), 454 et, length - 5); 455 } 456 p += 5; 457 length -= 5; 458 caplen -= 5; 459 460 switch (orgcode) { 461 case OUI_ENCAP_ETHER: 462 case OUI_CISCO_90: 463 /* 464 * This is an encapsulated Ethernet packet, 465 * or a packet bridged by some piece of 466 * Cisco hardware; the protocol ID is 467 * an Ethernet protocol type. 468 */ 469 ret = ethertype_print(ndo, et, p, length, caplen, src, dst); 470 if (ret) 471 return (ret); 472 break; 473 474 case OUI_APPLETALK: 475 if (et == ETHERTYPE_ATALK) { 476 /* 477 * No, I have no idea why Apple used one 478 * of their own OUIs, rather than 479 * 0x000000, and an Ethernet packet 480 * type, for Appletalk data packets, 481 * but used 0x000000 and an Ethernet 482 * packet type for AARP packets. 483 */ 484 ret = ethertype_print(ndo, et, p, length, caplen, src, dst); 485 if (ret) 486 return (ret); 487 } 488 break; 489 490 case OUI_CISCO: 491 switch (et) { 492 case PID_CISCO_CDP: 493 cdp_print(ndo, p, length); 494 return (1); 495 case PID_CISCO_DTP: 496 dtp_print(ndo, p, length); 497 return (1); 498 case PID_CISCO_UDLD: 499 udld_print(ndo, p, length); 500 return (1); 501 case PID_CISCO_VTP: 502 vtp_print(ndo, p, length); 503 return (1); 504 case PID_CISCO_PVST: 505 case PID_CISCO_VLANBRIDGE: 506 stp_print(ndo, p, length); 507 return (1); 508 default: 509 break; 510 } 511 break; 512 513 case OUI_RFC2684: 514 switch (et) { 515 516 case PID_RFC2684_ETH_FCS: 517 case PID_RFC2684_ETH_NOFCS: 518 /* 519 * XXX - remove the last two bytes for 520 * PID_RFC2684_ETH_FCS? 521 */ 522 /* 523 * Skip the padding. 524 */ 525 ND_TCHECK_LEN(p, bridge_pad); 526 caplen -= bridge_pad; 527 length -= bridge_pad; 528 p += bridge_pad; 529 530 /* 531 * What remains is an Ethernet packet. 532 */ 533 ether_print(ndo, p, length, caplen, NULL, NULL); 534 return (1); 535 536 case PID_RFC2684_802_5_FCS: 537 case PID_RFC2684_802_5_NOFCS: 538 /* 539 * XXX - remove the last two bytes for 540 * PID_RFC2684_ETH_FCS? 541 */ 542 /* 543 * Skip the padding, but not the Access 544 * Control field. 545 */ 546 ND_TCHECK_LEN(p, bridge_pad); 547 caplen -= bridge_pad; 548 length -= bridge_pad; 549 p += bridge_pad; 550 551 /* 552 * What remains is an 802.5 Token Ring 553 * packet. 554 */ 555 token_print(ndo, p, length, caplen); 556 return (1); 557 558 case PID_RFC2684_FDDI_FCS: 559 case PID_RFC2684_FDDI_NOFCS: 560 /* 561 * XXX - remove the last two bytes for 562 * PID_RFC2684_ETH_FCS? 563 */ 564 /* 565 * Skip the padding. 566 */ 567 ND_TCHECK_LEN(p, bridge_pad + 1); 568 caplen -= bridge_pad + 1; 569 length -= bridge_pad + 1; 570 p += bridge_pad + 1; 571 572 /* 573 * What remains is an FDDI packet. 574 */ 575 fddi_print(ndo, p, length, caplen); 576 return (1); 577 578 case PID_RFC2684_BPDU: 579 stp_print(ndo, p, length); 580 return (1); 581 } 582 } 583 if (!ndo->ndo_eflag) { 584 /* 585 * Nobody printed the link-layer addresses, so print them, if 586 * we have any. 587 */ 588 if (src != NULL && dst != NULL) { 589 ND_PRINT("%s > %s ", 590 (src->addr_string)(ndo, src->addr), 591 (dst->addr_string)(ndo, dst->addr)); 592 } 593 /* 594 * Print the SNAP header, but if the OUI is 000000, don't 595 * bother printing it, and report the PID as being an 596 * ethertype. 597 */ 598 if (orgcode == 0x000000) { 599 ND_PRINT("SNAP, ethertype %s (0x%04x), length %u: ", 600 tok2str(ethertype_values, "Unknown", et), 601 et, length); 602 } else { 603 ND_PRINT("SNAP, oui %s (0x%06x), pid %s (0x%04x), length %u: ", 604 tok2str(oui_values, "Unknown", orgcode), 605 orgcode, 606 tok2str(oui_to_struct_tok(orgcode), "Unknown", et), 607 et, length); 608 } 609 } 610 return (0); 611 612 trunc: 613 nd_print_trunc(ndo); 614 return (1); 615 } 616