Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_frame_relay.c
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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@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 #include <machine/clock.h> 61 62 #include <netgraph/ng_message.h> 63 #include <netgraph/netgraph.h> 64 #include <netgraph/ng_frame_relay.h> 65 66 /* 67 * Line info, and status per channel. 68 */ 69 struct ctxinfo { /* one per active hook */ 70 u_int flags; 71 #define CHAN_VALID 0x01 /* assigned to a channel */ 72 #define CHAN_ACTIVE 0x02 /* bottom level active */ 73 int dlci; /* the dlci assigned to this context */ 74 hook_p hook; /* if there's a hook assigned.. */ 75 }; 76 77 #define MAX_CT 16 /* # of dlci's active at a time (POWER OF 2!) */ 78 struct frmrel_softc { 79 int unit; /* which card are we? */ 80 int datahooks; /* number of data hooks attached */ 81 node_p node; /* netgraph node */ 82 int addrlen; /* address header length */ 83 int flags; /* state */ 84 int mtu; /* guess */ 85 u_char remote_seq; /* sequence number the remote sent */ 86 u_char local_seq; /* sequence number the remote rcvd */ 87 u_short ALT[1024]; /* map DLCIs to CTX */ 88 #define CTX_VALID 0x8000 /* this bit means it's a valid CTX */ 89 #define CTX_VALUE (MAX_CT - 1) /* mask for context part */ 90 struct ctxinfo channel[MAX_CT]; 91 struct ctxinfo downstream; 92 }; 93 typedef struct frmrel_softc *sc_p; 94 95 #define BYTEX_EA 0x01 /* End Address. Always 0 on byte1 */ 96 #define BYTE1_C_R 0x02 97 #define BYTE2_FECN 0x08 /* forwards congestion notification */ 98 #define BYTE2_BECN 0x04 /* Backward congestion notification */ 99 #define BYTE2_DE 0x02 /* Discard elligability */ 100 #define LASTBYTE_D_C 0x02 /* last byte is dl_core or dlci info */ 101 102 /* Used to do headers */ 103 static struct segment { 104 u_char mask; 105 u_char shift; 106 u_char width; 107 } makeup[] = { 108 { 0xfc, 2, 6 }, 109 { 0xf0, 4, 4 }, 110 { 0xfe, 1, 7 }, 111 { 0xfc, 2, 6 } 112 }; 113 114 #define SHIFTIN(segment, byte, dlci) \ 115 { \ 116 (dlci) <<= (segment)->width; \ 117 (dlci) |= \ 118 (((byte) & (segment)->mask) >> (segment)->shift); \ 119 } 120 121 #define SHIFTOUT(segment, byte, dlci) \ 122 { \ 123 (byte) |= (((dlci) << (segment)->shift) & (segment)->mask); \ 124 (dlci) >>= (segment)->width; \ 125 } 126 127 /* Netgraph methods */ 128 static ng_constructor_t ngfrm_constructor; 129 static ng_shutdown_t ngfrm_rmnode; 130 static ng_newhook_t ngfrm_newhook; 131 static ng_rcvdata_t ngfrm_rcvdata; 132 static ng_disconnect_t ngfrm_disconnect; 133 134 /* Other internal functions */ 135 static int ngfrm_decode(node_p node, struct mbuf * m, meta_p meta); 136 static int ngfrm_addrlen(char *hdr); 137 static int ngfrm_allocate_CTX(sc_p sc, int dlci); 138 139 /* Netgraph type */ 140 static struct ng_type typestruct = { 141 NG_VERSION, 142 NG_FRAMERELAY_NODE_TYPE, 143 NULL, 144 ngfrm_constructor, 145 NULL, 146 ngfrm_rmnode, 147 ngfrm_newhook, 148 NULL, 149 NULL, 150 ngfrm_rcvdata, 151 ngfrm_rcvdata, 152 ngfrm_disconnect, 153 NULL 154 }; 155 NETGRAPH_INIT(framerelay, &typestruct); 156 157 /* 158 * Given a DLCI, return the index of the context table entry for it, 159 * Allocating a new one if needs be, or -1 if none available. 160 */ 161 static int 162 ngfrm_allocate_CTX(sc_p sc, int dlci) 163 { 164 u_int ctxnum = -1; /* what ctx number we are using */ 165 volatile struct ctxinfo *CTXp = NULL; 166 167 /* Sanity check the dlci value */ 168 if (dlci > 1023) 169 return (-1); 170 171 /* Check to see if we already have an entry for this DLCI */ 172 if (sc->ALT[dlci]) { 173 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) { 174 CTXp = sc->channel + ctxnum; 175 } else { 176 ctxnum = -1; 177 sc->ALT[dlci] = 0; /* paranoid but... */ 178 } 179 } 180 181 /* 182 * If the index has no valid entry yet, then we need to allocate a 183 * CTX number to it 184 */ 185 if (CTXp == NULL) { 186 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) { 187 /* 188 * If the VALID flag is empty it is unused 189 */ 190 if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) { 191 bzero(sc->channel + ctxnum, 192 sizeof(struct ctxinfo)); 193 CTXp = sc->channel + ctxnum; 194 sc->ALT[dlci] = ctxnum | CTX_VALID; 195 sc->channel[ctxnum].dlci = dlci; 196 sc->channel[ctxnum].flags = CHAN_VALID; 197 break; 198 } 199 } 200 } 201 202 /* 203 * If we still don't have a CTX pointer, then we never found a free 204 * spot so give up now.. 205 */ 206 if (!CTXp) { 207 log(LOG_ERR, "No CTX available for dlci %d\n", dlci); 208 return (-1); 209 } 210 return (ctxnum); 211 } 212 213 /* 214 * Node constructor 215 */ 216 static int 217 ngfrm_constructor(node_p *nodep) 218 { 219 sc_p sc; 220 int error = 0; 221 222 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT); 223 if (!sc) 224 return (ENOMEM); 225 bzero(sc, sizeof(*sc)); 226 if ((error = ng_make_node_common(&typestruct, nodep))) { 227 FREE(sc, M_NETGRAPH); 228 return (error); 229 } 230 sc->addrlen = 2; /* default */ 231 232 /* Link the node and our private info */ 233 (*nodep)->private = sc; 234 sc->node = *nodep; 235 return (0); 236 } 237 238 /* 239 * Add a new hook 240 * 241 * We allow hooks called "debug", "downstream" and dlci[0-1023] 242 * The hook's private info points to our stash of info about that 243 * channel. A NULL pointer is debug and a DLCI of -1 means downstream. 244 */ 245 static int 246 ngfrm_newhook(node_p node, hook_p hook, const char *name) 247 { 248 const sc_p sc = node->private; 249 const char *cp; 250 char *eptr; 251 int dlci = 0; 252 int ctxnum; 253 254 /* Check if it's our friend the control hook */ 255 if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) { 256 hook->private = NULL; /* paranoid */ 257 return (0); 258 } 259 260 /* 261 * All other hooks either start with 'dlci' and have a decimal 262 * trailing channel number up to 4 digits, or are the downstream 263 * hook. 264 */ 265 if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI, 266 strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) { 267 268 /* It must be the downstream connection */ 269 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0) 270 return EINVAL; 271 272 /* Make sure we haven't already got one (paranoid) */ 273 if (sc->downstream.hook) 274 return (EADDRINUSE); 275 276 /* OK add it */ 277 hook->private = &sc->downstream; 278 sc->downstream.hook = hook; 279 sc->downstream.dlci = -1; 280 sc->downstream.flags |= CHAN_ACTIVE; 281 sc->datahooks++; 282 return (0); 283 } 284 285 /* Must be a dlci hook at this point */ 286 cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI); 287 if (!isdigit(*cp) || (cp[0] == '' && cp[1] != '\0')) 288 return (EINVAL); 289 dlci = (int)strtoul(cp, &eptr, 10); 290 if (*eptr != '\0' || dlci < 0 || dlci > 1023) 291 return (EINVAL); 292 293 /* 294 * We have a dlci, now either find it, or allocate it. It's possible 295 * that we might have seen packets for it already and made an entry 296 * for it. 297 */ 298 ctxnum = ngfrm_allocate_CTX(sc, dlci); 299 if (ctxnum == -1) 300 return (ENOBUFS); 301 302 /* 303 * Be paranoid: if it's got a hook already, that dlci is in use . 304 * Generic code can not catch all the synonyms (e.g. dlci016 vs 305 * dlci16) 306 */ 307 if (sc->channel[ctxnum].hook != NULL) 308 return (EADDRINUSE); 309 310 /* 311 * Put our hooks into it (pun not intended) 312 */ 313 sc->channel[ctxnum].flags |= CHAN_ACTIVE; 314 hook->private = sc->channel + ctxnum; 315 sc->channel[ctxnum].hook = hook; 316 sc->datahooks++; 317 return (0); 318 } 319 320 /* 321 * Count up the size of the address header if we don't already know 322 */ 323 int 324 ngfrm_addrlen(char *hdr) 325 { 326 if (hdr[0] & BYTEX_EA) 327 return 0; 328 if (hdr[1] & BYTEX_EA) 329 return 2; 330 if (hdr[2] & BYTEX_EA) 331 return 3; 332 if (hdr[3] & BYTEX_EA) 333 return 4; 334 return 0; 335 } 336 337 /* 338 * Receive data packet 339 */ 340 static int 341 ngfrm_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 342 { 343 struct ctxinfo *const ctxp = hook->private; 344 int error = 0; 345 int dlci; 346 sc_p sc; 347 int alen; 348 char *data; 349 350 /* Data doesn't come in from just anywhere (e.g debug hook) */ 351 if (ctxp == NULL) { 352 error = ENETDOWN; 353 goto bad; 354 } 355 356 /* If coming from downstream, decode it to a channel */ 357 dlci = ctxp->dlci; 358 if (dlci == -1) 359 return (ngfrm_decode(hook->node, m, meta)); 360 361 /* Derive the softc we will need */ 362 sc = hook->node->private; 363 364 /* If there is no live channel, throw it away */ 365 if ((sc->downstream.hook == NULL) 366 || ((ctxp->flags & CHAN_ACTIVE) == 0)) { 367 error = ENETDOWN; 368 goto bad; 369 } 370 371 /* Store the DLCI on the front of the packet */ 372 alen = sc->addrlen; 373 if (alen == 0) 374 alen = 2; /* default value for transmit */ 375 M_PREPEND(m, alen, M_DONTWAIT); 376 if (m == NULL) { 377 error = ENOBUFS; 378 goto bad; 379 } 380 data = mtod(m, char *); 381 382 /* 383 * Shift the lowest bits into the address field untill we are done. 384 * First byte is MSBits of addr so work backwards. 385 */ 386 switch (alen) { 387 case 2: 388 data[0] = data[1] = '\0'; 389 SHIFTOUT(makeup + 1, data[1], dlci); 390 SHIFTOUT(makeup + 0, data[0], dlci); 391 data[1] |= BYTEX_EA; 392 break; 393 case 3: 394 data[0] = data[1] = data[2] = '\0'; 395 SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 396 SHIFTOUT(makeup + 1, data[1], dlci); 397 SHIFTOUT(makeup + 0, data[0], dlci); 398 data[2] |= BYTEX_EA; 399 break; 400 case 4: 401 data[0] = data[1] = data[2] = data[3] = '\0'; 402 SHIFTOUT(makeup + 3, data[3], dlci); 403 SHIFTOUT(makeup + 2, data[2], dlci); 404 SHIFTOUT(makeup + 1, data[1], dlci); 405 SHIFTOUT(makeup + 0, data[0], dlci); 406 data[3] |= BYTEX_EA; 407 break; 408 default: 409 panic(__FUNCTION__); 410 } 411 412 /* Send it */ 413 NG_SEND_DATA(error, sc->downstream.hook, m, meta); 414 return (error); 415 416 bad: 417 NG_FREE_DATA(m, meta); 418 return (error); 419 } 420 421 /* 422 * Decode an incoming frame coming from the switch 423 */ 424 static int 425 ngfrm_decode(node_p node, struct mbuf *m, meta_p meta) 426 { 427 const sc_p sc = node->private; 428 char *data; 429 int alen; 430 u_int dlci = 0; 431 int error = 0; 432 int ctxnum; 433 434 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) { 435 error = ENOBUFS; 436 goto out; 437 } 438 data = mtod(m, char *); 439 if ((alen = sc->addrlen) == 0) { 440 sc->addrlen = alen = ngfrm_addrlen(data); 441 } 442 switch (alen) { 443 case 2: 444 SHIFTIN(makeup + 0, data[0], dlci); 445 SHIFTIN(makeup + 1, data[1], dlci); 446 break; 447 case 3: 448 SHIFTIN(makeup + 0, data[0], dlci); 449 SHIFTIN(makeup + 1, data[1], dlci); 450 SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 451 break; 452 case 4: 453 SHIFTIN(makeup + 0, data[0], dlci); 454 SHIFTIN(makeup + 1, data[1], dlci); 455 SHIFTIN(makeup + 2, data[2], dlci); 456 SHIFTIN(makeup + 3, data[3], dlci); 457 break; 458 default: 459 error = EINVAL; 460 goto out; 461 } 462 463 if (dlci > 1023) { 464 error = EINVAL; 465 goto out; 466 } 467 ctxnum = sc->ALT[dlci]; 468 if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) { 469 /* Send it */ 470 m_adj(m, alen); 471 NG_SEND_DATA(error, sc->channel[ctxnum].hook, m, meta); 472 return (error); 473 } else { 474 error = ENETDOWN; 475 } 476 out: 477 NG_FREE_DATA(m, meta); 478 return (error); 479 } 480 481 /* 482 * Shutdown node 483 */ 484 static int 485 ngfrm_rmnode(node_p node) 486 { 487 const sc_p sc = node->private; 488 489 node->flags |= NG_INVALID; 490 ng_cutlinks(node); 491 ng_unname(node); 492 node->private = NULL; 493 FREE(sc, M_NETGRAPH); 494 ng_unref(sc->node); 495 return (0); 496 } 497 498 /* 499 * Hook disconnection 500 * 501 * Invalidate the private data associated with this dlci. 502 * For this type, removal of the last link resets tries to destroy the node. 503 */ 504 static int 505 ngfrm_disconnect(hook_p hook) 506 { 507 const sc_p sc = hook->node->private; 508 struct ctxinfo *const cp = hook->private; 509 int dlci; 510 511 /* If it's a regular dlci hook, then free resources etc.. */ 512 if (cp != NULL) { 513 cp->hook = NULL; 514 dlci = cp->dlci; 515 if (dlci != -1) 516 sc->ALT[dlci] = 0; 517 cp->flags = 0; 518 sc->datahooks--; 519 } 520 if (hook->node->numhooks == 0) 521 ng_rmnode(hook->node); 522 return (0); 523 }
Cache object: fd64163ff004b398b65d639ffc4e8c00
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