1 /* 2 * ng_frame_relay.c 3 */ 4 5 /*- 6 * Copyright (c) 1996-1999 Whistle Communications, Inc. 7 * All rights reserved. 8 * 9 * Subject to the following obligations and disclaimer of warranty, use and 10 * redistribution of this software, in source or object code forms, with or 11 * without modifications are expressly permitted by Whistle Communications; 12 * provided, however, that: 13 * 1. Any and all reproductions of the source or object code must include the 14 * copyright notice above and the following disclaimer of warranties; and 15 * 2. No rights are granted, in any manner or form, to use Whistle 16 * Communications, Inc. trademarks, including the mark "WHISTLE 17 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as 18 * such appears in the above copyright notice or in the software. 19 * 20 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND 21 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO 22 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, 23 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF 24 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. 25 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY 26 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS 27 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE. 28 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES 29 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING 30 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 31 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR 32 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY 36 * OF SUCH DAMAGE. 37 * 38 * Author: Julian Elischer <julian@freebsd.org> 39 * 40 * $FreeBSD: src/sys/netgraph/ng_frame_relay.c,v 1.25 2006/01/14 21:49:31 glebius Exp $ 41 * $DragonFly: src/sys/netgraph7/ng_frame_relay.c,v 1.2 2008/06/26 23:05:35 dillon Exp $ 42 * $Whistle: ng_frame_relay.c,v 1.20 1999/11/01 09:24:51 julian Exp $ 43 */ 44 45 /* 46 * This node implements the frame relay protocol, not including 47 * the LMI line management. This means basically keeping track 48 * of which DLCI's are active, doing frame (de)multiplexing, etc. 49 * 50 * It has a 'downstream' hook that goes to the line, and a 51 * hook for each DLCI (eg, 'dlci16'). 52 */ 53 54 #include <sys/param.h> 55 #include <sys/systm.h> 56 #include <sys/kernel.h> 57 #include <sys/errno.h> 58 #include <sys/malloc.h> 59 #include <sys/mbuf.h> 60 #include <sys/syslog.h> 61 #include <sys/ctype.h> 62 63 #include <netgraph7/ng_message.h> 64 #include <netgraph7/netgraph.h> 65 #include "ng_frame_relay.h" 66 67 /* 68 * Line info, and status per channel. 69 */ 70 struct ctxinfo { /* one per active hook */ 71 u_int flags; 72 #define CHAN_VALID 0x01 /* assigned to a channel */ 73 #define CHAN_ACTIVE 0x02 /* bottom level active */ 74 int dlci; /* the dlci assigned to this context */ 75 hook_p hook; /* if there's a hook assigned.. */ 76 }; 77 78 #define MAX_CT 16 /* # of dlci's active at a time (POWER OF 2!) */ 79 struct frmrel_softc { 80 int unit; /* which card are we? */ 81 int datahooks; /* number of data hooks attached */ 82 node_p node; /* netgraph node */ 83 int addrlen; /* address header length */ 84 int flags; /* state */ 85 int mtu; /* guess */ 86 u_char remote_seq; /* sequence number the remote sent */ 87 u_char local_seq; /* sequence number the remote rcvd */ 88 u_short ALT[1024]; /* map DLCIs to CTX */ 89 #define CTX_VALID 0x8000 /* this bit means it's a valid CTX */ 90 #define CTX_VALUE (MAX_CT - 1) /* mask for context part */ 91 struct ctxinfo channel[MAX_CT]; 92 struct ctxinfo downstream; 93 }; 94 typedef struct frmrel_softc *sc_p; 95 96 #define BYTEX_EA 0x01 /* End Address. Always 0 on byte1 */ 97 #define BYTE1_C_R 0x02 98 #define BYTE2_FECN 0x08 /* forwards congestion notification */ 99 #define BYTE2_BECN 0x04 /* Backward congestion notification */ 100 #define BYTE2_DE 0x02 /* Discard elligability */ 101 #define LASTBYTE_D_C 0x02 /* last byte is dl_core or dlci info */ 102 103 /* Used to do headers */ 104 static const struct segment { 105 u_char mask; 106 u_char shift; 107 u_char width; 108 } makeup[] = { 109 { 0xfc, 2, 6 }, 110 { 0xf0, 4, 4 }, 111 { 0xfe, 1, 7 }, 112 { 0xfc, 2, 6 } 113 }; 114 115 #define SHIFTIN(segment, byte, dlci) \ 116 { \ 117 (dlci) <<= (segment)->width; \ 118 (dlci) |= \ 119 (((byte) & (segment)->mask) >> (segment)->shift); \ 120 } 121 122 #define SHIFTOUT(segment, byte, dlci) \ 123 { \ 124 (byte) |= (((dlci) << (segment)->shift) & (segment)->mask); \ 125 (dlci) >>= (segment)->width; \ 126 } 127 128 /* Netgraph methods */ 129 static ng_constructor_t ngfrm_constructor; 130 static ng_shutdown_t ngfrm_shutdown; 131 static ng_newhook_t ngfrm_newhook; 132 static ng_rcvdata_t ngfrm_rcvdata; 133 static ng_disconnect_t ngfrm_disconnect; 134 135 /* Other internal functions */ 136 static int ngfrm_decode(node_p node, item_p item); 137 static int ngfrm_addrlen(char *hdr); 138 static int ngfrm_allocate_CTX(sc_p sc, int dlci); 139 140 /* Netgraph type */ 141 static struct ng_type typestruct = { 142 .version = NG_ABI_VERSION, 143 .name = NG_FRAMERELAY_NODE_TYPE, 144 .constructor = ngfrm_constructor, 145 .shutdown = ngfrm_shutdown, 146 .newhook = ngfrm_newhook, 147 .rcvdata = ngfrm_rcvdata, 148 .disconnect = ngfrm_disconnect, 149 }; 150 NETGRAPH_INIT(framerelay, &typestruct); 151 152 /* 153 * Given a DLCI, return the index of the context table entry for it, 154 * Allocating a new one if needs be, or -1 if none available. 155 */ 156 static int 157 ngfrm_allocate_CTX(sc_p sc, int dlci) 158 { 159 u_int ctxnum = -1; /* what ctx number we are using */ 160 volatile struct ctxinfo *CTXp = NULL; 161 162 /* Sanity check the dlci value */ 163 if (dlci > 1023) 164 return (-1); 165 166 /* Check to see if we already have an entry for this DLCI */ 167 if (sc->ALT[dlci]) { 168 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) { 169 CTXp = sc->channel + ctxnum; 170 } else { 171 ctxnum = -1; 172 sc->ALT[dlci] = 0; /* paranoid but... */ 173 } 174 } 175 176 /* 177 * If the index has no valid entry yet, then we need to allocate a 178 * CTX number to it 179 */ 180 if (CTXp == NULL) { 181 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) { 182 /* 183 * If the VALID flag is empty it is unused 184 */ 185 if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) { 186 bzero(sc->channel + ctxnum, 187 sizeof(struct ctxinfo)); 188 CTXp = sc->channel + ctxnum; 189 sc->ALT[dlci] = ctxnum | CTX_VALID; 190 sc->channel[ctxnum].dlci = dlci; 191 sc->channel[ctxnum].flags = CHAN_VALID; 192 break; 193 } 194 } 195 } 196 197 /* 198 * If we still don't have a CTX pointer, then we never found a free 199 * spot so give up now.. 200 */ 201 if (!CTXp) { 202 log(LOG_ERR, "No CTX available for dlci %d\n", dlci); 203 return (-1); 204 } 205 return (ctxnum); 206 } 207 208 /* 209 * Node constructor 210 */ 211 static int 212 ngfrm_constructor(node_p node) 213 { 214 sc_p sc; 215 216 sc = kmalloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_NULLOK | M_ZERO); 217 if (!sc) 218 return (ENOMEM); 219 sc->addrlen = 2; /* default */ 220 221 /* Link the node and our private info */ 222 NG_NODE_SET_PRIVATE(node, sc); 223 sc->node = node; 224 return (0); 225 } 226 227 /* 228 * Add a new hook 229 * 230 * We allow hooks called "debug", "downstream" and dlci[0-1023] 231 * The hook's private info points to our stash of info about that 232 * channel. A NULL pointer is debug and a DLCI of -1 means downstream. 233 */ 234 static int 235 ngfrm_newhook(node_p node, hook_p hook, const char *name) 236 { 237 const sc_p sc = NG_NODE_PRIVATE(node); 238 const char *cp; 239 char *eptr; 240 int dlci = 0; 241 int ctxnum; 242 243 /* Check if it's our friend the control hook */ 244 if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) { 245 NG_HOOK_SET_PRIVATE(hook, NULL); /* paranoid */ 246 return (0); 247 } 248 249 /* 250 * All other hooks either start with 'dlci' and have a decimal 251 * trailing channel number up to 4 digits, or are the downstream 252 * hook. 253 */ 254 if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI, 255 strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) { 256 257 /* It must be the downstream connection */ 258 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0) 259 return EINVAL; 260 261 /* Make sure we haven't already got one (paranoid) */ 262 if (sc->downstream.hook) 263 return (EADDRINUSE); 264 265 /* OK add it */ 266 NG_HOOK_SET_PRIVATE(hook, &sc->downstream); 267 sc->downstream.hook = hook; 268 sc->downstream.dlci = -1; 269 sc->downstream.flags |= CHAN_ACTIVE; 270 sc->datahooks++; 271 return (0); 272 } 273 274 /* Must be a dlci hook at this point */ 275 cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI); 276 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0')) 277 return (EINVAL); 278 dlci = (int)strtoul(cp, &eptr, 10); 279 if (*eptr != '\0' || dlci < 0 || dlci > 1023) 280 return (EINVAL); 281 282 /* 283 * We have a dlci, now either find it, or allocate it. It's possible 284 * that we might have seen packets for it already and made an entry 285 * for it. 286 */ 287 ctxnum = ngfrm_allocate_CTX(sc, dlci); 288 if (ctxnum == -1) 289 return (ENOBUFS); 290 291 /* 292 * Be paranoid: if it's got a hook already, that dlci is in use . 293 * Generic code can not catch all the synonyms (e.g. dlci016 vs 294 * dlci16) 295 */ 296 if (sc->channel[ctxnum].hook != NULL) 297 return (EADDRINUSE); 298 299 /* 300 * Put our hooks into it (pun not intended) 301 */ 302 sc->channel[ctxnum].flags |= CHAN_ACTIVE; 303 NG_HOOK_SET_PRIVATE(hook, sc->channel + ctxnum); 304 sc->channel[ctxnum].hook = hook; 305 sc->datahooks++; 306 return (0); 307 } 308 309 /* 310 * Count up the size of the address header if we don't already know 311 */ 312 int 313 ngfrm_addrlen(char *hdr) 314 { 315 if (hdr[0] & BYTEX_EA) 316 return 0; 317 if (hdr[1] & BYTEX_EA) 318 return 2; 319 if (hdr[2] & BYTEX_EA) 320 return 3; 321 if (hdr[3] & BYTEX_EA) 322 return 4; 323 return 0; 324 } 325 326 /* 327 * Receive data packet 328 */ 329 static int 330 ngfrm_rcvdata(hook_p hook, item_p item) 331 { 332 struct ctxinfo *const ctxp = NG_HOOK_PRIVATE(hook); 333 struct mbuf *m = NULL; 334 int error = 0; 335 int dlci; 336 sc_p sc; 337 int alen; 338 char *data; 339 340 /* Data doesn't come in from just anywhere (e.g debug hook) */ 341 if (ctxp == NULL) { 342 error = ENETDOWN; 343 goto bad; 344 } 345 346 /* If coming from downstream, decode it to a channel */ 347 dlci = ctxp->dlci; 348 if (dlci == -1) 349 return (ngfrm_decode(NG_HOOK_NODE(hook), item)); 350 351 NGI_GET_M(item, m); 352 /* Derive the softc we will need */ 353 sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 354 355 /* If there is no live channel, throw it away */ 356 if ((sc->downstream.hook == NULL) 357 || ((ctxp->flags & CHAN_ACTIVE) == 0)) { 358 error = ENETDOWN; 359 goto bad; 360 } 361 362 /* Store the DLCI on the front of the packet */ 363 alen = sc->addrlen; 364 if (alen == 0) 365 alen = 2; /* default value for transmit */ 366 M_PREPEND(m, alen, MB_DONTWAIT); 367 if (m == NULL) { 368 error = ENOBUFS; 369 goto bad; 370 } 371 data = mtod(m, char *); 372 373 /* 374 * Shift the lowest bits into the address field untill we are done. 375 * First byte is MSBits of addr so work backwards. 376 */ 377 switch (alen) { 378 case 2: 379 data[0] = data[1] = '\0'; 380 SHIFTOUT(makeup + 1, data[1], dlci); 381 SHIFTOUT(makeup + 0, data[0], dlci); 382 data[1] |= BYTEX_EA; 383 break; 384 case 3: 385 data[0] = data[1] = data[2] = '\0'; 386 SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 387 SHIFTOUT(makeup + 1, data[1], dlci); 388 SHIFTOUT(makeup + 0, data[0], dlci); 389 data[2] |= BYTEX_EA; 390 break; 391 case 4: 392 data[0] = data[1] = data[2] = data[3] = '\0'; 393 SHIFTOUT(makeup + 3, data[3], dlci); 394 SHIFTOUT(makeup + 2, data[2], dlci); 395 SHIFTOUT(makeup + 1, data[1], dlci); 396 SHIFTOUT(makeup + 0, data[0], dlci); 397 data[3] |= BYTEX_EA; 398 break; 399 default: 400 panic(__func__); 401 } 402 403 /* Send it */ 404 NG_FWD_NEW_DATA(error, item, sc->downstream.hook, m); 405 return (error); 406 407 bad: 408 NG_FREE_ITEM(item); 409 NG_FREE_M(m); 410 return (error); 411 } 412 413 /* 414 * Decode an incoming frame coming from the switch 415 */ 416 static int 417 ngfrm_decode(node_p node, item_p item) 418 { 419 const sc_p sc = NG_NODE_PRIVATE(node); 420 char *data; 421 int alen; 422 u_int dlci = 0; 423 int error = 0; 424 int ctxnum; 425 struct mbuf *m; 426 427 NGI_GET_M(item, m); 428 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) { 429 error = ENOBUFS; 430 goto out; 431 } 432 data = mtod(m, char *); 433 if ((alen = sc->addrlen) == 0) { 434 sc->addrlen = alen = ngfrm_addrlen(data); 435 } 436 switch (alen) { 437 case 2: 438 SHIFTIN(makeup + 0, data[0], dlci); 439 SHIFTIN(makeup + 1, data[1], dlci); 440 break; 441 case 3: 442 SHIFTIN(makeup + 0, data[0], dlci); 443 SHIFTIN(makeup + 1, data[1], dlci); 444 SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 445 break; 446 case 4: 447 SHIFTIN(makeup + 0, data[0], dlci); 448 SHIFTIN(makeup + 1, data[1], dlci); 449 SHIFTIN(makeup + 2, data[2], dlci); 450 SHIFTIN(makeup + 3, data[3], dlci); 451 break; 452 default: 453 error = EINVAL; 454 goto out; 455 } 456 457 if (dlci > 1023) { 458 error = EINVAL; 459 goto out; 460 } 461 ctxnum = sc->ALT[dlci]; 462 if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) { 463 /* Send it */ 464 m_adj(m, alen); 465 NG_FWD_NEW_DATA(error, item, sc->channel[ctxnum].hook, m); 466 return (error); 467 } else { 468 error = ENETDOWN; 469 } 470 out: 471 NG_FREE_ITEM(item); 472 NG_FREE_M(m); 473 return (error); 474 } 475 476 /* 477 * Shutdown node 478 */ 479 static int 480 ngfrm_shutdown(node_p node) 481 { 482 const sc_p sc = NG_NODE_PRIVATE(node); 483 484 NG_NODE_SET_PRIVATE(node, NULL); 485 kfree(sc, M_NETGRAPH); 486 NG_NODE_UNREF(node); 487 return (0); 488 } 489 490 /* 491 * Hook disconnection 492 * 493 * Invalidate the private data associated with this dlci. 494 * For this type, removal of the last link resets tries to destroy the node. 495 */ 496 static int 497 ngfrm_disconnect(hook_p hook) 498 { 499 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 500 struct ctxinfo *const cp = NG_HOOK_PRIVATE(hook); 501 int dlci; 502 503 /* If it's a regular dlci hook, then free resources etc.. */ 504 if (cp != NULL) { 505 cp->hook = NULL; 506 dlci = cp->dlci; 507 if (dlci != -1) 508 sc->ALT[dlci] = 0; 509 cp->flags = 0; 510 sc->datahooks--; 511 } 512 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0) 513 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) 514 ng_rmnode_self(NG_HOOK_NODE(hook)); 515 return (0); 516 } 517