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 Elischer <julian@freebsd.org> 38 * 39 * $FreeBSD$ 40 * $Whistle: ng_frame_relay.c,v 1.20 1999/11/01 09:24:51 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/errno.h> 56 #include <sys/malloc.h> 57 #include <sys/mbuf.h> 58 #include <sys/syslog.h> 59 #include <sys/ctype.h> 60 61 #include <netgraph/ng_message.h> 62 #include <netgraph/netgraph.h> 63 #include <netgraph/ng_frame_relay.h> 64 65 /* 66 * Line info, and status per channel. 67 */ 68 struct ctxinfo { /* one per active hook */ 69 u_int flags; 70 #define CHAN_VALID 0x01 /* assigned to a channel */ 71 #define CHAN_ACTIVE 0x02 /* bottom level active */ 72 int dlci; /* the dlci assigned to this context */ 73 hook_p hook; /* if there's a hook assigned.. */ 74 }; 75 76 #define MAX_CT 16 /* # of dlci's active at a time (POWER OF 2!) */ 77 struct frmrel_softc { 78 int unit; /* which card are we? */ 79 int datahooks; /* number of data hooks attached */ 80 node_p node; /* netgraph node */ 81 int addrlen; /* address header length */ 82 int flags; /* state */ 83 int mtu; /* guess */ 84 u_char remote_seq; /* sequence number the remote sent */ 85 u_char local_seq; /* sequence number the remote rcvd */ 86 u_short ALT[1024]; /* map DLCIs to CTX */ 87 #define CTX_VALID 0x8000 /* this bit means it's a valid CTX */ 88 #define CTX_VALUE (MAX_CT - 1) /* mask for context part */ 89 struct ctxinfo channel[MAX_CT]; 90 struct ctxinfo downstream; 91 }; 92 typedef struct frmrel_softc *sc_p; 93 94 #define BYTEX_EA 0x01 /* End Address. Always 0 on byte1 */ 95 #define BYTE1_C_R 0x02 96 #define BYTE2_FECN 0x08 /* forwards congestion notification */ 97 #define BYTE2_BECN 0x04 /* Backward congestion notification */ 98 #define BYTE2_DE 0x02 /* Discard elligability */ 99 #define LASTBYTE_D_C 0x02 /* last byte is dl_core or dlci info */ 100 101 /* Used to do headers */ 102 static struct segment { 103 u_char mask; 104 u_char shift; 105 u_char width; 106 } makeup[] = { 107 { 0xfc, 2, 6 }, 108 { 0xf0, 4, 4 }, 109 { 0xfe, 1, 7 }, 110 { 0xfc, 2, 6 } 111 }; 112 113 #define SHIFTIN(segment, byte, dlci) \ 114 { \ 115 (dlci) <<= (segment)->width; \ 116 (dlci) |= \ 117 (((byte) & (segment)->mask) >> (segment)->shift); \ 118 } 119 120 #define SHIFTOUT(segment, byte, dlci) \ 121 { \ 122 (byte) |= (((dlci) << (segment)->shift) & (segment)->mask); \ 123 (dlci) >>= (segment)->width; \ 124 } 125 126 /* Netgraph methods */ 127 static ng_constructor_t ngfrm_constructor; 128 static ng_shutdown_t ngfrm_shutdown; 129 static ng_newhook_t ngfrm_newhook; 130 static ng_rcvdata_t ngfrm_rcvdata; 131 static ng_disconnect_t ngfrm_disconnect; 132 133 /* Other internal functions */ 134 static int ngfrm_decode(node_p node, item_p item); 135 static int ngfrm_addrlen(char *hdr); 136 static int ngfrm_allocate_CTX(sc_p sc, int dlci); 137 138 /* Netgraph type */ 139 static struct ng_type typestruct = { 140 NG_ABI_VERSION, 141 NG_FRAMERELAY_NODE_TYPE, 142 NULL, 143 ngfrm_constructor, 144 NULL, 145 ngfrm_shutdown, 146 ngfrm_newhook, 147 NULL, 148 NULL, 149 ngfrm_rcvdata, 150 ngfrm_disconnect, 151 NULL 152 }; 153 NETGRAPH_INIT(framerelay, &typestruct); 154 155 /* 156 * Given a DLCI, return the index of the context table entry for it, 157 * Allocating a new one if needs be, or -1 if none available. 158 */ 159 static int 160 ngfrm_allocate_CTX(sc_p sc, int dlci) 161 { 162 u_int ctxnum = -1; /* what ctx number we are using */ 163 volatile struct ctxinfo *CTXp = NULL; 164 165 /* Sanity check the dlci value */ 166 if (dlci > 1023) 167 return (-1); 168 169 /* Check to see if we already have an entry for this DLCI */ 170 if (sc->ALT[dlci]) { 171 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) { 172 CTXp = sc->channel + ctxnum; 173 } else { 174 ctxnum = -1; 175 sc->ALT[dlci] = 0; /* paranoid but... */ 176 } 177 } 178 179 /* 180 * If the index has no valid entry yet, then we need to allocate a 181 * CTX number to it 182 */ 183 if (CTXp == NULL) { 184 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) { 185 /* 186 * If the VALID flag is empty it is unused 187 */ 188 if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) { 189 bzero(sc->channel + ctxnum, 190 sizeof(struct ctxinfo)); 191 CTXp = sc->channel + ctxnum; 192 sc->ALT[dlci] = ctxnum | CTX_VALID; 193 sc->channel[ctxnum].dlci = dlci; 194 sc->channel[ctxnum].flags = CHAN_VALID; 195 break; 196 } 197 } 198 } 199 200 /* 201 * If we still don't have a CTX pointer, then we never found a free 202 * spot so give up now.. 203 */ 204 if (!CTXp) { 205 log(LOG_ERR, "No CTX available for dlci %d\n", dlci); 206 return (-1); 207 } 208 return (ctxnum); 209 } 210 211 /* 212 * Node constructor 213 */ 214 static int 215 ngfrm_constructor(node_p node) 216 { 217 sc_p sc; 218 219 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO); 220 if (!sc) 221 return (ENOMEM); 222 sc->addrlen = 2; /* default */ 223 224 /* Link the node and our private info */ 225 NG_NODE_SET_PRIVATE(node, sc); 226 sc->node = node; 227 return (0); 228 } 229 230 /* 231 * Add a new hook 232 * 233 * We allow hooks called "debug", "downstream" and dlci[0-1023] 234 * The hook's private info points to our stash of info about that 235 * channel. A NULL pointer is debug and a DLCI of -1 means downstream. 236 */ 237 static int 238 ngfrm_newhook(node_p node, hook_p hook, const char *name) 239 { 240 const sc_p sc = NG_NODE_PRIVATE(node); 241 const char *cp; 242 char *eptr; 243 int dlci = 0; 244 int ctxnum; 245 246 /* Check if it's our friend the control hook */ 247 if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) { 248 NG_HOOK_SET_PRIVATE(hook, NULL); /* paranoid */ 249 return (0); 250 } 251 252 /* 253 * All other hooks either start with 'dlci' and have a decimal 254 * trailing channel number up to 4 digits, or are the downstream 255 * hook. 256 */ 257 if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI, 258 strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) { 259 260 /* It must be the downstream connection */ 261 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0) 262 return EINVAL; 263 264 /* Make sure we haven't already got one (paranoid) */ 265 if (sc->downstream.hook) 266 return (EADDRINUSE); 267 268 /* OK add it */ 269 NG_HOOK_SET_PRIVATE(hook, &sc->downstream); 270 sc->downstream.hook = hook; 271 sc->downstream.dlci = -1; 272 sc->downstream.flags |= CHAN_ACTIVE; 273 sc->datahooks++; 274 return (0); 275 } 276 277 /* Must be a dlci hook at this point */ 278 cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI); 279 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0')) 280 return (EINVAL); 281 dlci = (int)strtoul(cp, &eptr, 10); 282 if (*eptr != '\0' || dlci < 0 || dlci > 1023) 283 return (EINVAL); 284 285 /* 286 * We have a dlci, now either find it, or allocate it. It's possible 287 * that we might have seen packets for it already and made an entry 288 * for it. 289 */ 290 ctxnum = ngfrm_allocate_CTX(sc, dlci); 291 if (ctxnum == -1) 292 return (ENOBUFS); 293 294 /* 295 * Be paranoid: if it's got a hook already, that dlci is in use . 296 * Generic code can not catch all the synonyms (e.g. dlci016 vs 297 * dlci16) 298 */ 299 if (sc->channel[ctxnum].hook != NULL) 300 return (EADDRINUSE); 301 302 /* 303 * Put our hooks into it (pun not intended) 304 */ 305 sc->channel[ctxnum].flags |= CHAN_ACTIVE; 306 NG_HOOK_SET_PRIVATE(hook, sc->channel + ctxnum); 307 sc->channel[ctxnum].hook = hook; 308 sc->datahooks++; 309 return (0); 310 } 311 312 /* 313 * Count up the size of the address header if we don't already know 314 */ 315 int 316 ngfrm_addrlen(char *hdr) 317 { 318 if (hdr[0] & BYTEX_EA) 319 return 0; 320 if (hdr[1] & BYTEX_EA) 321 return 2; 322 if (hdr[2] & BYTEX_EA) 323 return 3; 324 if (hdr[3] & BYTEX_EA) 325 return 4; 326 return 0; 327 } 328 329 /* 330 * Receive data packet 331 */ 332 static int 333 ngfrm_rcvdata(hook_p hook, item_p item) 334 { 335 struct ctxinfo *const ctxp = NG_HOOK_PRIVATE(hook); 336 int error = 0; 337 int dlci; 338 sc_p sc; 339 int alen; 340 char *data; 341 struct mbuf *m; 342 343 /* Data doesn't come in from just anywhere (e.g debug hook) */ 344 if (ctxp == NULL) { 345 error = ENETDOWN; 346 goto bad; 347 } 348 349 /* If coming from downstream, decode it to a channel */ 350 dlci = ctxp->dlci; 351 if (dlci == -1) 352 return (ngfrm_decode(NG_HOOK_NODE(hook), item)); 353 354 NGI_GET_M(item, m); 355 /* Derive the softc we will need */ 356 sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 357 358 /* If there is no live channel, throw it away */ 359 if ((sc->downstream.hook == NULL) 360 || ((ctxp->flags & CHAN_ACTIVE) == 0)) { 361 error = ENETDOWN; 362 goto bad; 363 } 364 365 /* Store the DLCI on the front of the packet */ 366 alen = sc->addrlen; 367 if (alen == 0) 368 alen = 2; /* default value for transmit */ 369 M_PREPEND(m, alen, M_DONTWAIT); 370 if (m == NULL) { 371 error = ENOBUFS; 372 goto bad; 373 } 374 data = mtod(m, char *); 375 376 /* 377 * Shift the lowest bits into the address field untill we are done. 378 * First byte is MSBits of addr so work backwards. 379 */ 380 switch (alen) { 381 case 2: 382 data[0] = data[1] = '\0'; 383 SHIFTOUT(makeup + 1, data[1], dlci); 384 SHIFTOUT(makeup + 0, data[0], dlci); 385 data[1] |= BYTEX_EA; 386 break; 387 case 3: 388 data[0] = data[1] = data[2] = '\0'; 389 SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 390 SHIFTOUT(makeup + 1, data[1], dlci); 391 SHIFTOUT(makeup + 0, data[0], dlci); 392 data[2] |= BYTEX_EA; 393 break; 394 case 4: 395 data[0] = data[1] = data[2] = data[3] = '\0'; 396 SHIFTOUT(makeup + 3, data[3], dlci); 397 SHIFTOUT(makeup + 2, data[2], dlci); 398 SHIFTOUT(makeup + 1, data[1], dlci); 399 SHIFTOUT(makeup + 0, data[0], dlci); 400 data[3] |= BYTEX_EA; 401 break; 402 default: 403 panic(__func__); 404 } 405 406 /* Send it */ 407 NG_FWD_NEW_DATA(error, item, sc->downstream.hook, m); 408 return (error); 409 410 bad: 411 NG_FREE_ITEM(item); 412 NG_FREE_M(m); 413 return (error); 414 } 415 416 /* 417 * Decode an incoming frame coming from the switch 418 */ 419 static int 420 ngfrm_decode(node_p node, item_p item) 421 { 422 const sc_p sc = NG_NODE_PRIVATE(node); 423 char *data; 424 int alen; 425 u_int dlci = 0; 426 int error = 0; 427 int ctxnum; 428 struct mbuf *m; 429 430 NGI_GET_M(item, m); 431 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) { 432 error = ENOBUFS; 433 goto out; 434 } 435 data = mtod(m, char *); 436 if ((alen = sc->addrlen) == 0) { 437 sc->addrlen = alen = ngfrm_addrlen(data); 438 } 439 switch (alen) { 440 case 2: 441 SHIFTIN(makeup + 0, data[0], dlci); 442 SHIFTIN(makeup + 1, data[1], dlci); 443 break; 444 case 3: 445 SHIFTIN(makeup + 0, data[0], dlci); 446 SHIFTIN(makeup + 1, data[1], dlci); 447 SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 448 break; 449 case 4: 450 SHIFTIN(makeup + 0, data[0], dlci); 451 SHIFTIN(makeup + 1, data[1], dlci); 452 SHIFTIN(makeup + 2, data[2], dlci); 453 SHIFTIN(makeup + 3, data[3], dlci); 454 break; 455 default: 456 error = EINVAL; 457 goto out; 458 } 459 460 if (dlci > 1023) { 461 error = EINVAL; 462 goto out; 463 } 464 ctxnum = sc->ALT[dlci]; 465 if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) { 466 /* Send it */ 467 m_adj(m, alen); 468 NG_FWD_NEW_DATA(error, item, sc->channel[ctxnum].hook, m); 469 return (error); 470 } else { 471 error = ENETDOWN; 472 } 473 out: 474 NG_FREE_ITEM(item); 475 NG_FREE_M(m); 476 return (error); 477 } 478 479 /* 480 * Shutdown node 481 */ 482 static int 483 ngfrm_shutdown(node_p node) 484 { 485 const sc_p sc = NG_NODE_PRIVATE(node); 486 487 NG_NODE_SET_PRIVATE(node, NULL); 488 FREE(sc, M_NETGRAPH); 489 NG_NODE_UNREF(node); 490 return (0); 491 } 492 493 /* 494 * Hook disconnection 495 * 496 * Invalidate the private data associated with this dlci. 497 * For this type, removal of the last link resets tries to destroy the node. 498 */ 499 static int 500 ngfrm_disconnect(hook_p hook) 501 { 502 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 503 struct ctxinfo *const cp = NG_HOOK_PRIVATE(hook); 504 int dlci; 505 506 /* If it's a regular dlci hook, then free resources etc.. */ 507 if (cp != NULL) { 508 cp->hook = NULL; 509 dlci = cp->dlci; 510 if (dlci != -1) 511 sc->ALT[dlci] = 0; 512 cp->flags = 0; 513 sc->datahooks--; 514 } 515 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0) 516 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) 517 ng_rmnode_self(NG_HOOK_NODE(hook)); 518 return (0); 519 } 520