1 2 /* 3 * ng_frame_relay.c 4 * 5 * Copyright (c) 1996-1999 Whistle Communications, Inc. 6 * All rights reserved. 7 * 8 * Subject to the following obligations and disclaimer of warranty, use and 9 * redistribution of this software, in source or object code forms, with or 10 * without modifications are expressly permitted by Whistle Communications; 11 * provided, however, that: 12 * 1. Any and all reproductions of the source or object code must include the 13 * copyright notice above and the following disclaimer of warranties; and 14 * 2. No rights are granted, in any manner or form, to use Whistle 15 * Communications, Inc. trademarks, including the mark "WHISTLE 16 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as 17 * such appears in the above copyright notice or in the software. 18 * 19 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND 20 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO 21 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, 22 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF 23 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. 24 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY 25 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS 26 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE. 27 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES 28 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING 29 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 30 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR 31 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY 32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 34 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY 35 * OF SUCH DAMAGE. 36 * 37 * Author: Julian Elisher <julian@whistle.com> 38 * 39 * $FreeBSD$ 40 * $Whistle: ng_frame_relay.c,v 1.16 1999/01/28 23:54:53 julian Exp $ 41 */ 42 43 /* 44 * This node implements the frame relay protocol, not including 45 * the LMI line management. This means basically keeping track 46 * of which DLCI's are active, doing frame (de)multiplexing, etc. 47 * 48 * It has a 'downstream' hook that goes to the line, and a 49 * hook for each DLCI (eg, 'dlci16'). 50 */ 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/kernel.h> 55 #include <sys/conf.h> 56 #include <sys/errno.h> 57 #include <sys/malloc.h> 58 #include <sys/mbuf.h> 59 #include <sys/socket.h> 60 #include <sys/syslog.h> 61 #include <machine/clock.h> 62 63 #include <netgraph/ng_message.h> 64 #include <netgraph/netgraph.h> 65 #include <netgraph/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 char nodename[NG_NODELEN + 1]; /* store our node name */ 82 int datahooks; /* number of data hooks attached */ 83 node_p node; /* netgraph node */ 84 int addrlen; /* address header length */ 85 int flags; /* state */ 86 int mtu; /* guess */ 87 u_char remote_seq; /* sequence number the remote sent */ 88 u_char local_seq; /* sequence number the remote rcvd */ 89 u_short ALT[1024]; /* map DLCIs to CTX */ 90 #define CTX_VALID 0x8000 /* this bit means it's a valid CTX */ 91 #define CTX_VALUE (MAX_CT - 1) /* mask for context part */ 92 struct ctxinfo channel[MAX_CT]; 93 struct ctxinfo downstream; 94 }; 95 typedef struct frmrel_softc *sc_p; 96 97 #define BYTEX_EA 0x01 /* End Address. Always 0 on byte1 */ 98 #define BYTE1_C_R 0x02 99 #define BYTE2_FECN 0x08 /* forwards congestion notification */ 100 #define BYTE2_BECN 0x04 /* Backward congestion notification */ 101 #define BYTE2_DE 0x02 /* Discard elligability */ 102 #define LASTBYTE_D_C 0x02 /* last byte is dl_core or dlci info */ 103 104 /* Used to do headers */ 105 static struct segment { 106 u_char mask; 107 u_char shift; 108 u_char width; 109 } makeup[] = { 110 { 0xfc, 2, 6 }, 111 { 0xf0, 4, 4 }, 112 { 0xfe, 1, 7 }, 113 { 0xfc, 2, 6 } 114 }; 115 116 #define SHIFTIN(segment, byte, dlci) \ 117 { \ 118 (dlci) <<= (segment)->width; \ 119 (dlci) |= \ 120 (((byte) & (segment)->mask) >> (segment)->shift); \ 121 } 122 123 #define SHIFTOUT(segment, byte, dlci) \ 124 { \ 125 (byte) |= (((dlci) << (segment)->shift) & (segment)->mask); \ 126 (dlci) >>= (segment)->width; \ 127 } 128 129 /* Netgraph methods */ 130 static int ngfrm_constructor(node_p *nodep); 131 static int ngfrm_rmnode(node_p node); 132 static int ngfrm_newhook(node_p node, hook_p hook, const char *name); 133 static int ngfrm_rcvdata(hook_p hook, struct mbuf *m, meta_p meta); 134 static int ngfrm_disconnect(hook_p hook); 135 136 /* Other internal functions */ 137 static int ngfrm_decode(node_p node, struct mbuf * m, meta_p meta); 138 static int ngfrm_addrlen(char *hdr); 139 static int ngfrm_allocate_CTX(sc_p sc, int dlci); 140 141 /* Netgraph type */ 142 static struct ng_type typestruct = { 143 NG_VERSION, 144 NG_FRAMERELAY_NODE_TYPE, 145 NULL, 146 ngfrm_constructor, 147 NULL, 148 ngfrm_rmnode, 149 ngfrm_newhook, 150 NULL, 151 NULL, 152 ngfrm_rcvdata, 153 ngfrm_rcvdata, 154 ngfrm_disconnect 155 }; 156 NETGRAPH_INIT(framerelay, &typestruct); 157 158 /* 159 * Given a DLCI, return the index of the context table entry for it, 160 * Allocating a new one if needs be, or -1 if none available. 161 */ 162 static int 163 ngfrm_allocate_CTX(sc_p sc, int dlci) 164 { 165 u_int ctxnum = -1; /* what ctx number we are using */ 166 volatile struct ctxinfo *CTXp = NULL; 167 168 /* Sanity check the dlci value */ 169 if (dlci > 1023) 170 return (-1); 171 172 /* Check to see if we already have an entry for this DLCI */ 173 if (sc->ALT[dlci]) { 174 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) { 175 CTXp = sc->channel + ctxnum; 176 } else { 177 ctxnum = -1; 178 sc->ALT[dlci] = 0; /* paranoid but... */ 179 } 180 } 181 182 /* 183 * If the index has no valid entry yet, then we need to allocate a 184 * CTX number to it 185 */ 186 if (CTXp == NULL) { 187 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) { 188 /* 189 * If the VALID flag is empty it is unused 190 */ 191 if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) { 192 bzero(sc->channel + ctxnum, 193 sizeof(struct ctxinfo)); 194 CTXp = sc->channel + ctxnum; 195 sc->ALT[dlci] = ctxnum | CTX_VALID; 196 sc->channel[ctxnum].dlci = dlci; 197 sc->channel[ctxnum].flags = CHAN_VALID; 198 break; 199 } 200 } 201 } 202 203 /* 204 * If we still don't have a CTX pointer, then we never found a free 205 * spot so give up now.. 206 */ 207 if (!CTXp) { 208 log(LOG_ERR, "No CTX available for dlci %d\n", dlci); 209 return (-1); 210 } 211 return (ctxnum); 212 } 213 214 /* 215 * Node constructor 216 */ 217 static int 218 ngfrm_constructor(node_p *nodep) 219 { 220 sc_p sc; 221 int error = 0; 222 223 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT); 224 if (!sc) 225 return (ENOMEM); 226 bzero(sc, sizeof(*sc)); 227 if ((error = ng_make_node_common(&typestruct, nodep))) { 228 FREE(sc, M_NETGRAPH); 229 return (error); 230 } 231 sc->addrlen = 2; /* default */ 232 233 /* Link the node and our private info */ 234 (*nodep)->private = sc; 235 sc->node = *nodep; 236 return (0); 237 } 238 239 /* 240 * Add a new hook 241 * 242 * We allow hooks called "debug", "downstream" and dlci[0-1023] 243 * The hook's private info points to our stash of info about that 244 * channel. A NULL pointer is debug and a DLCI of -1 means downstream. 245 */ 246 static int 247 ngfrm_newhook(node_p node, hook_p hook, const char *name) 248 { 249 const sc_p sc = node->private; 250 const char *cp; 251 char c = '\0'; 252 int digits = 0; 253 int dlci = 0; 254 int ctxnum; 255 256 /* Check if it's our friend the control hook */ 257 if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) { 258 hook->private = NULL; /* paranoid */ 259 return (0); 260 } 261 262 /* 263 * All other hooks either start with 'dlci' and have a decimal 264 * trailing channel number up to 4 digits, or are the downstream 265 * hook. 266 */ 267 if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI, 268 strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) { 269 270 /* It must be the downstream connection */ 271 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0) 272 return EINVAL; 273 274 /* Make sure we haven't already got one (paranoid) */ 275 if (sc->downstream.hook) 276 return (EADDRINUSE); 277 278 /* OK add it */ 279 hook->private = &sc->downstream; 280 sc->downstream.hook = hook; 281 sc->downstream.dlci = -1; 282 sc->downstream.flags |= CHAN_ACTIVE; 283 sc->datahooks++; 284 return (0); 285 } 286 287 /* Must be a dlci hook at this point */ 288 cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI); 289 while ((digits < 5) && ((c = *cp++) >= '0') && (c <= '9')) { 290 dlci *= 10; 291 dlci += c - '0'; 292 digits++; 293 } 294 if ((c != 0) || (digits == 5) || (dlci < 0) || (dlci > 1023)) 295 return (EINVAL); 296 /* 297 * We have a dlci, now either find it, or allocate it. It's possible 298 * that we might have seen packets for it already and made an entry 299 * for it. 300 */ 301 ctxnum = ngfrm_allocate_CTX(sc, dlci); 302 if (ctxnum == -1) 303 return (ENOBUFS); 304 305 /* 306 * Be paranoid: if it's got a hook already, that dlci is in use . 307 * Generic code can not catch all the synonyms (e.g. dlci016 vs 308 * dlci16) 309 */ 310 if (sc->channel[ctxnum].hook != NULL) 311 return (EADDRINUSE); 312 313 /* 314 * Put our hooks into it (pun not intended) 315 */ 316 sc->channel[ctxnum].flags |= CHAN_ACTIVE; 317 hook->private = sc->channel + ctxnum; 318 sc->channel[ctxnum].hook = hook; 319 sc->datahooks++; 320 return (0); 321 } 322 323 /* 324 * Count up the size of the address header if we don't already know 325 */ 326 int 327 ngfrm_addrlen(char *hdr) 328 { 329 if (hdr[0] & BYTEX_EA) 330 return 0; 331 if (hdr[1] & BYTEX_EA) 332 return 2; 333 if (hdr[2] & BYTEX_EA) 334 return 3; 335 if (hdr[3] & BYTEX_EA) 336 return 4; 337 return 0; 338 } 339 340 /* 341 * Receive data packet 342 */ 343 static int 344 ngfrm_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 345 { 346 struct ctxinfo *const ctxp = hook->private; 347 int error = 0; 348 int dlci; 349 sc_p sc; 350 int alen; 351 char *data; 352 353 /* Data doesn't come in from just anywhere (e.g debug hook) */ 354 if (ctxp == NULL) { 355 error = ENETDOWN; 356 goto bad; 357 } 358 359 /* If coming from downstream, decode it to a channel */ 360 dlci = ctxp->dlci; 361 if (dlci == -1) 362 return (ngfrm_decode(hook->node, m, meta)); 363 364 /* Derive the softc we will need */ 365 sc = hook->node->private; 366 367 /* If there is no live channel, throw it away */ 368 if ((sc->downstream.hook == NULL) 369 || ((ctxp->flags & CHAN_ACTIVE) == 0)) { 370 error = ENETDOWN; 371 goto bad; 372 } 373 374 /* Store the DLCI on the front of the packet */ 375 alen = sc->addrlen; 376 if (alen == 0) 377 alen = 2; /* default value for transmit */ 378 M_PREPEND(m, alen, M_DONTWAIT); 379 if (m == NULL) { 380 error = ENOBUFS; 381 goto bad; 382 } 383 data = mtod(m, char *); 384 385 /* 386 * Shift the lowest bits into the address field untill we are done. 387 * First byte is MSBits of addr so work backwards. 388 */ 389 switch (alen) { 390 case 2: 391 data[0] = data[1] = '\0'; 392 SHIFTOUT(makeup + 1, data[1], dlci); 393 SHIFTOUT(makeup + 0, data[0], dlci); 394 data[1] |= BYTEX_EA; 395 break; 396 case 3: 397 data[0] = data[1] = data[2] = '\0'; 398 SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 399 SHIFTOUT(makeup + 1, data[1], dlci); 400 SHIFTOUT(makeup + 0, data[0], dlci); 401 data[2] |= BYTEX_EA; 402 break; 403 case 4: 404 data[0] = data[1] = data[2] = data[3] = '\0'; 405 SHIFTOUT(makeup + 3, data[3], dlci); 406 SHIFTOUT(makeup + 2, data[2], dlci); 407 SHIFTOUT(makeup + 1, data[1], dlci); 408 SHIFTOUT(makeup + 0, data[0], dlci); 409 data[3] |= BYTEX_EA; 410 break; 411 default: 412 panic(__FUNCTION__); 413 } 414 415 /* Send it */ 416 NG_SEND_DATA(error, sc->downstream.hook, m, meta); 417 return (error); 418 419 bad: 420 NG_FREE_DATA(m, meta); 421 return (error); 422 } 423 424 /* 425 * Decode an incoming frame coming from the switch 426 */ 427 static int 428 ngfrm_decode(node_p node, struct mbuf *m, meta_p meta) 429 { 430 const sc_p sc = node->private; 431 char *data; 432 int alen; 433 u_int dlci = 0; 434 int error = 0; 435 int ctxnum; 436 437 if ((m = m_pullup(m, 4)) == NULL) { 438 error = ENOBUFS; 439 goto out; 440 } 441 data = mtod(m, char *); 442 if ((alen = sc->addrlen) == 0) { 443 sc->addrlen = alen = ngfrm_addrlen(data); 444 } 445 switch (alen) { 446 case 2: 447 SHIFTIN(makeup + 0, data[0], dlci); 448 SHIFTIN(makeup + 1, data[1], dlci); 449 break; 450 case 3: 451 SHIFTIN(makeup + 0, data[0], dlci); 452 SHIFTIN(makeup + 1, data[1], dlci); 453 SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 454 break; 455 case 4: 456 SHIFTIN(makeup + 0, data[0], dlci); 457 SHIFTIN(makeup + 1, data[1], dlci); 458 SHIFTIN(makeup + 2, data[2], dlci); 459 SHIFTIN(makeup + 3, data[3], dlci); 460 break; 461 default: 462 error = EINVAL; 463 goto out; 464 } 465 466 if (dlci > 1023) { 467 error = EINVAL; 468 goto out; 469 } 470 ctxnum = sc->ALT[dlci]; 471 if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) { 472 /* Send it */ 473 m_adj(m, alen); 474 NG_SEND_DATA(error, sc->channel[ctxnum].hook, m, meta); 475 return (error); 476 } else { 477 error = ENETDOWN; 478 } 479 out: 480 NG_FREE_DATA(m, meta); 481 return (error); 482 } 483 484 /* 485 * Shutdown node 486 */ 487 static int 488 ngfrm_rmnode(node_p node) 489 { 490 const sc_p sc = node->private; 491 492 node->flags |= NG_INVALID; 493 ng_cutlinks(node); 494 ng_unname(node); 495 node->private = NULL; 496 FREE(sc, M_NETGRAPH); 497 ng_unref(sc->node); 498 return (0); 499 } 500 501 /* 502 * Hook disconnection 503 * 504 * Invalidate the private data associated with this dlci. 505 * For this type, removal of the last link resets tries to destroy the node. 506 */ 507 static int 508 ngfrm_disconnect(hook_p hook) 509 { 510 const sc_p sc = hook->node->private; 511 struct ctxinfo *const cp = hook->private; 512 int dlci; 513 514 /* If it's a regular dlci hook, then free resources etc.. */ 515 if (cp != NULL) { 516 cp->hook = NULL; 517 dlci = cp->dlci; 518 if (dlci != -1) 519 sc->ALT[dlci] = 0; 520 cp->flags = 0; 521 sc->datahooks--; 522 } 523 if (hook->node->numhooks == 0) 524 ng_rmnode(hook->node); 525 return (0); 526 } 527