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 * 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 * $FreeBSD$ 41 * $Whistle: ng_frame_relay.c,v 1.20 1999/11/01 09:24:51 julian Exp $ 42 */ 43 44 /* 45 * This node implements the frame relay protocol, not including 46 * the LMI line management. This means basically keeping track 47 * of which DLCI's are active, doing frame (de)multiplexing, etc. 48 * 49 * It has a 'downstream' hook that goes to the line, and a 50 * hook for each DLCI (eg, 'dlci16'). 51 */ 52 53 #include <sys/param.h> 54 #include <sys/systm.h> 55 #include <sys/kernel.h> 56 #include <sys/errno.h> 57 #include <sys/malloc.h> 58 #include <sys/mbuf.h> 59 #include <sys/syslog.h> 60 #include <sys/ctype.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 const 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_shutdown; 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, item_p item); 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 .version = NG_ABI_VERSION, 142 .name = NG_FRAMERELAY_NODE_TYPE, 143 .constructor = ngfrm_constructor, 144 .shutdown = ngfrm_shutdown, 145 .newhook = ngfrm_newhook, 146 .rcvdata = ngfrm_rcvdata, 147 .disconnect = ngfrm_disconnect, 148 }; 149 NETGRAPH_INIT(framerelay, &typestruct); 150 151 #define ERROUT(x) do { error = (x); goto done; } while (0) 152 153 /* 154 * Given a DLCI, return the index of the context table entry for it, 155 * Allocating a new one if needs be, or -1 if none available. 156 */ 157 static int 158 ngfrm_allocate_CTX(sc_p sc, int dlci) 159 { 160 u_int ctxnum = -1; /* what ctx number we are using */ 161 volatile struct ctxinfo *CTXp = NULL; 162 163 /* Sanity check the dlci value */ 164 if (dlci > 1023) 165 return (-1); 166 167 /* Check to see if we already have an entry for this DLCI */ 168 if (sc->ALT[dlci]) { 169 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) { 170 CTXp = sc->channel + ctxnum; 171 } else { 172 ctxnum = -1; 173 sc->ALT[dlci] = 0; /* paranoid but... */ 174 } 175 } 176 177 /* 178 * If the index has no valid entry yet, then we need to allocate a 179 * CTX number to it 180 */ 181 if (CTXp == NULL) { 182 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) { 183 /* 184 * If the VALID flag is empty it is unused 185 */ 186 if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) { 187 bzero(sc->channel + ctxnum, 188 sizeof(struct ctxinfo)); 189 CTXp = sc->channel + ctxnum; 190 sc->ALT[dlci] = ctxnum | CTX_VALID; 191 sc->channel[ctxnum].dlci = dlci; 192 sc->channel[ctxnum].flags = CHAN_VALID; 193 break; 194 } 195 } 196 } 197 198 /* 199 * If we still don't have a CTX pointer, then we never found a free 200 * spot so give up now.. 201 */ 202 if (!CTXp) { 203 log(LOG_ERR, "No CTX available for dlci %d\n", dlci); 204 return (-1); 205 } 206 return (ctxnum); 207 } 208 209 /* 210 * Node constructor 211 */ 212 static int 213 ngfrm_constructor(node_p node) 214 { 215 sc_p sc; 216 217 sc = malloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO); 218 sc->addrlen = 2; /* default */ 219 220 /* Link the node and our private info */ 221 NG_NODE_SET_PRIVATE(node, sc); 222 sc->node = node; 223 return (0); 224 } 225 226 /* 227 * Add a new hook 228 * 229 * We allow hooks called "debug", "downstream" and dlci[0-1023] 230 * The hook's private info points to our stash of info about that 231 * channel. A NULL pointer is debug and a DLCI of -1 means downstream. 232 */ 233 static int 234 ngfrm_newhook(node_p node, hook_p hook, const char *name) 235 { 236 const sc_p sc = NG_NODE_PRIVATE(node); 237 const char *cp; 238 char *eptr; 239 int dlci = 0; 240 int ctxnum; 241 242 /* Check if it's our friend the control hook */ 243 if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) { 244 NG_HOOK_SET_PRIVATE(hook, NULL); /* paranoid */ 245 return (0); 246 } 247 248 /* 249 * All other hooks either start with 'dlci' and have a decimal 250 * trailing channel number up to 4 digits, or are the downstream 251 * hook. 252 */ 253 if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI, 254 strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) { 255 /* It must be the downstream connection */ 256 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0) 257 return EINVAL; 258 259 /* Make sure we haven't already got one (paranoid) */ 260 if (sc->downstream.hook) 261 return (EADDRINUSE); 262 263 /* OK add it */ 264 NG_HOOK_SET_PRIVATE(hook, &sc->downstream); 265 sc->downstream.hook = hook; 266 sc->downstream.dlci = -1; 267 sc->downstream.flags |= CHAN_ACTIVE; 268 sc->datahooks++; 269 return (0); 270 } 271 272 /* Must be a dlci hook at this point */ 273 cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI); 274 if (!isdigit(*cp) || (cp[0] == '' && cp[1] != '\0')) 275 return (EINVAL); 276 dlci = (int)strtoul(cp, &eptr, 10); 277 if (*eptr != '\0' || dlci < 0 || dlci > 1023) 278 return (EINVAL); 279 280 /* 281 * We have a dlci, now either find it, or allocate it. It's possible 282 * that we might have seen packets for it already and made an entry 283 * for it. 284 */ 285 ctxnum = ngfrm_allocate_CTX(sc, dlci); 286 if (ctxnum == -1) 287 return (ENOBUFS); 288 289 /* 290 * Be paranoid: if it's got a hook already, that dlci is in use . 291 * Generic code can not catch all the synonyms (e.g. dlci016 vs 292 * dlci16) 293 */ 294 if (sc->channel[ctxnum].hook != NULL) 295 return (EADDRINUSE); 296 297 /* 298 * Put our hooks into it (pun not intended) 299 */ 300 sc->channel[ctxnum].flags |= CHAN_ACTIVE; 301 NG_HOOK_SET_PRIVATE(hook, sc->channel + ctxnum); 302 sc->channel[ctxnum].hook = hook; 303 sc->datahooks++; 304 return (0); 305 } 306 307 /* 308 * Count up the size of the address header if we don't already know 309 */ 310 int 311 ngfrm_addrlen(char *hdr) 312 { 313 if (hdr[0] & BYTEX_EA) 314 return 0; 315 if (hdr[1] & BYTEX_EA) 316 return 2; 317 if (hdr[2] & BYTEX_EA) 318 return 3; 319 if (hdr[3] & BYTEX_EA) 320 return 4; 321 return 0; 322 } 323 324 /* 325 * Receive data packet 326 */ 327 static int 328 ngfrm_rcvdata(hook_p hook, item_p item) 329 { 330 struct ctxinfo *const ctxp = NG_HOOK_PRIVATE(hook); 331 struct mbuf *m = NULL; 332 int error = 0; 333 int dlci; 334 sc_p sc; 335 int alen; 336 char *data; 337 338 /* Data doesn't come in from just anywhere (e.g debug hook) */ 339 if (ctxp == NULL) 340 ERROUT(ENETDOWN); 341 342 /* If coming from downstream, decode it to a channel */ 343 dlci = ctxp->dlci; 344 if (dlci == -1) 345 return (ngfrm_decode(NG_HOOK_NODE(hook), item)); 346 347 NGI_GET_M(item, m); 348 /* Derive the softc we will need */ 349 sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 350 351 /* If there is no live channel, throw it away */ 352 if ((sc->downstream.hook == NULL) 353 || ((ctxp->flags & CHAN_ACTIVE) == 0)) 354 ERROUT(ENETDOWN); 355 356 /* Store the DLCI on the front of the packet */ 357 alen = sc->addrlen; 358 if (alen == 0) 359 alen = 2; /* default value for transmit */ 360 M_PREPEND(m, alen, M_NOWAIT); 361 if (m == NULL) 362 ERROUT(ENOBUFS); 363 data = mtod(m, char *); 364 365 /* 366 * Shift the lowest bits into the address field until we are done. 367 * First byte is MSBits of addr so work backwards. 368 */ 369 switch (alen) { 370 case 2: 371 data[0] = data[1] = '\0'; 372 SHIFTOUT(makeup + 1, data[1], dlci); 373 SHIFTOUT(makeup + 0, data[0], dlci); 374 data[1] |= BYTEX_EA; 375 break; 376 case 3: 377 data[0] = data[1] = data[2] = '\0'; 378 SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 379 SHIFTOUT(makeup + 1, data[1], dlci); 380 SHIFTOUT(makeup + 0, data[0], dlci); 381 data[2] |= BYTEX_EA; 382 break; 383 case 4: 384 data[0] = data[1] = data[2] = data[3] = '\0'; 385 SHIFTOUT(makeup + 3, data[3], dlci); 386 SHIFTOUT(makeup + 2, data[2], dlci); 387 SHIFTOUT(makeup + 1, data[1], dlci); 388 SHIFTOUT(makeup + 0, data[0], dlci); 389 data[3] |= BYTEX_EA; 390 break; 391 default: 392 panic("%s", __func__); 393 } 394 395 /* Send it */ 396 NG_FWD_NEW_DATA(error, item, sc->downstream.hook, m); 397 return (error); 398 399 done: 400 NG_FREE_ITEM(item); 401 NG_FREE_M(m); 402 return (error); 403 } 404 405 /* 406 * Decode an incoming frame coming from the switch 407 */ 408 static int 409 ngfrm_decode(node_p node, item_p item) 410 { 411 const sc_p sc = NG_NODE_PRIVATE(node); 412 char *data; 413 int alen; 414 u_int dlci = 0; 415 int error = 0; 416 int ctxnum; 417 struct mbuf *m; 418 419 NGI_GET_M(item, m); 420 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) 421 ERROUT(ENOBUFS); 422 data = mtod(m, char *); 423 if ((alen = sc->addrlen) == 0) { 424 sc->addrlen = alen = ngfrm_addrlen(data); 425 } 426 switch (alen) { 427 case 2: 428 SHIFTIN(makeup + 0, data[0], dlci); 429 SHIFTIN(makeup + 1, data[1], dlci); 430 break; 431 case 3: 432 SHIFTIN(makeup + 0, data[0], dlci); 433 SHIFTIN(makeup + 1, data[1], dlci); 434 SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 435 break; 436 case 4: 437 SHIFTIN(makeup + 0, data[0], dlci); 438 SHIFTIN(makeup + 1, data[1], dlci); 439 SHIFTIN(makeup + 2, data[2], dlci); 440 SHIFTIN(makeup + 3, data[3], dlci); 441 break; 442 default: 443 ERROUT(EINVAL); 444 } 445 446 if (dlci > 1023) 447 ERROUT(EINVAL); 448 ctxnum = sc->ALT[dlci]; 449 if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) { 450 /* Send it */ 451 m_adj(m, alen); 452 NG_FWD_NEW_DATA(error, item, sc->channel[ctxnum].hook, m); 453 return (error); 454 } else { 455 error = ENETDOWN; 456 } 457 done: 458 NG_FREE_ITEM(item); 459 NG_FREE_M(m); 460 return (error); 461 } 462 463 /* 464 * Shutdown node 465 */ 466 static int 467 ngfrm_shutdown(node_p node) 468 { 469 const sc_p sc = NG_NODE_PRIVATE(node); 470 471 NG_NODE_SET_PRIVATE(node, NULL); 472 free(sc, M_NETGRAPH); 473 NG_NODE_UNREF(node); 474 return (0); 475 } 476 477 /* 478 * Hook disconnection 479 * 480 * Invalidate the private data associated with this dlci. 481 * For this type, removal of the last link resets tries to destroy the node. 482 */ 483 static int 484 ngfrm_disconnect(hook_p hook) 485 { 486 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 487 struct ctxinfo *const cp = NG_HOOK_PRIVATE(hook); 488 int dlci; 489 490 /* If it's a regular dlci hook, then free resources etc.. */ 491 if (cp != NULL) { 492 cp->hook = NULL; 493 dlci = cp->dlci; 494 if (dlci != -1) 495 sc->ALT[dlci] = 0; 496 cp->flags = 0; 497 sc->datahooks--; 498 } 499 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0) 500 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) 501 ng_rmnode_self(NG_HOOK_NODE(hook)); 502 return (0); 503 }
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