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