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 Elischer <julian@freebsd.org> 38 * 39 * $FreeBSD: releng/5.3/sys/netgraph/ng_frame_relay.c 136588 2004-10-16 08:43:07Z cvs2svn $ 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 const 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 .version = NG_ABI_VERSION, 141 .name = NG_FRAMERELAY_NODE_TYPE, 142 .constructor = ngfrm_constructor, 143 .shutdown = ngfrm_shutdown, 144 .newhook = ngfrm_newhook, 145 .rcvdata = ngfrm_rcvdata, 146 .disconnect = ngfrm_disconnect, 147 }; 148 NETGRAPH_INIT(framerelay, &typestruct); 149 150 /* 151 * Given a DLCI, return the index of the context table entry for it, 152 * Allocating a new one if needs be, or -1 if none available. 153 */ 154 static int 155 ngfrm_allocate_CTX(sc_p sc, int dlci) 156 { 157 u_int ctxnum = -1; /* what ctx number we are using */ 158 volatile struct ctxinfo *CTXp = NULL; 159 160 /* Sanity check the dlci value */ 161 if (dlci > 1023) 162 return (-1); 163 164 /* Check to see if we already have an entry for this DLCI */ 165 if (sc->ALT[dlci]) { 166 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) { 167 CTXp = sc->channel + ctxnum; 168 } else { 169 ctxnum = -1; 170 sc->ALT[dlci] = 0; /* paranoid but... */ 171 } 172 } 173 174 /* 175 * If the index has no valid entry yet, then we need to allocate a 176 * CTX number to it 177 */ 178 if (CTXp == NULL) { 179 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) { 180 /* 181 * If the VALID flag is empty it is unused 182 */ 183 if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) { 184 bzero(sc->channel + ctxnum, 185 sizeof(struct ctxinfo)); 186 CTXp = sc->channel + ctxnum; 187 sc->ALT[dlci] = ctxnum | CTX_VALID; 188 sc->channel[ctxnum].dlci = dlci; 189 sc->channel[ctxnum].flags = CHAN_VALID; 190 break; 191 } 192 } 193 } 194 195 /* 196 * If we still don't have a CTX pointer, then we never found a free 197 * spot so give up now.. 198 */ 199 if (!CTXp) { 200 log(LOG_ERR, "No CTX available for dlci %d\n", dlci); 201 return (-1); 202 } 203 return (ctxnum); 204 } 205 206 /* 207 * Node constructor 208 */ 209 static int 210 ngfrm_constructor(node_p node) 211 { 212 sc_p sc; 213 214 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO); 215 if (!sc) 216 return (ENOMEM); 217 sc->addrlen = 2; /* default */ 218 219 /* Link the node and our private info */ 220 NG_NODE_SET_PRIVATE(node, sc); 221 sc->node = node; 222 return (0); 223 } 224 225 /* 226 * Add a new hook 227 * 228 * We allow hooks called "debug", "downstream" and dlci[0-1023] 229 * The hook's private info points to our stash of info about that 230 * channel. A NULL pointer is debug and a DLCI of -1 means downstream. 231 */ 232 static int 233 ngfrm_newhook(node_p node, hook_p hook, const char *name) 234 { 235 const sc_p sc = NG_NODE_PRIVATE(node); 236 const char *cp; 237 char *eptr; 238 int dlci = 0; 239 int ctxnum; 240 241 /* Check if it's our friend the control hook */ 242 if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) { 243 NG_HOOK_SET_PRIVATE(hook, NULL); /* paranoid */ 244 return (0); 245 } 246 247 /* 248 * All other hooks either start with 'dlci' and have a decimal 249 * trailing channel number up to 4 digits, or are the downstream 250 * hook. 251 */ 252 if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI, 253 strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) { 254 255 /* 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 int error = 0; 332 int dlci; 333 sc_p sc; 334 int alen; 335 char *data; 336 struct mbuf *m; 337 338 /* Data doesn't come in from just anywhere (e.g debug hook) */ 339 if (ctxp == NULL) { 340 error = ENETDOWN; 341 goto bad; 342 } 343 344 /* If coming from downstream, decode it to a channel */ 345 dlci = ctxp->dlci; 346 if (dlci == -1) 347 return (ngfrm_decode(NG_HOOK_NODE(hook), item)); 348 349 NGI_GET_M(item, m); 350 /* Derive the softc we will need */ 351 sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 352 353 /* If there is no live channel, throw it away */ 354 if ((sc->downstream.hook == NULL) 355 || ((ctxp->flags & CHAN_ACTIVE) == 0)) { 356 error = ENETDOWN; 357 goto bad; 358 } 359 360 /* Store the DLCI on the front of the packet */ 361 alen = sc->addrlen; 362 if (alen == 0) 363 alen = 2; /* default value for transmit */ 364 M_PREPEND(m, alen, M_DONTWAIT); 365 if (m == NULL) { 366 error = ENOBUFS; 367 goto bad; 368 } 369 data = mtod(m, char *); 370 371 /* 372 * Shift the lowest bits into the address field untill we are done. 373 * First byte is MSBits of addr so work backwards. 374 */ 375 switch (alen) { 376 case 2: 377 data[0] = data[1] = '\0'; 378 SHIFTOUT(makeup + 1, data[1], dlci); 379 SHIFTOUT(makeup + 0, data[0], dlci); 380 data[1] |= BYTEX_EA; 381 break; 382 case 3: 383 data[0] = data[1] = data[2] = '\0'; 384 SHIFTOUT(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 385 SHIFTOUT(makeup + 1, data[1], dlci); 386 SHIFTOUT(makeup + 0, data[0], dlci); 387 data[2] |= BYTEX_EA; 388 break; 389 case 4: 390 data[0] = data[1] = data[2] = data[3] = '\0'; 391 SHIFTOUT(makeup + 3, data[3], dlci); 392 SHIFTOUT(makeup + 2, data[2], dlci); 393 SHIFTOUT(makeup + 1, data[1], dlci); 394 SHIFTOUT(makeup + 0, data[0], dlci); 395 data[3] |= BYTEX_EA; 396 break; 397 default: 398 panic(__func__); 399 } 400 401 /* Send it */ 402 NG_FWD_NEW_DATA(error, item, sc->downstream.hook, m); 403 return (error); 404 405 bad: 406 NG_FREE_ITEM(item); 407 NG_FREE_M(m); 408 return (error); 409 } 410 411 /* 412 * Decode an incoming frame coming from the switch 413 */ 414 static int 415 ngfrm_decode(node_p node, item_p item) 416 { 417 const sc_p sc = NG_NODE_PRIVATE(node); 418 char *data; 419 int alen; 420 u_int dlci = 0; 421 int error = 0; 422 int ctxnum; 423 struct mbuf *m; 424 425 NGI_GET_M(item, m); 426 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) { 427 error = ENOBUFS; 428 goto out; 429 } 430 data = mtod(m, char *); 431 if ((alen = sc->addrlen) == 0) { 432 sc->addrlen = alen = ngfrm_addrlen(data); 433 } 434 switch (alen) { 435 case 2: 436 SHIFTIN(makeup + 0, data[0], dlci); 437 SHIFTIN(makeup + 1, data[1], dlci); 438 break; 439 case 3: 440 SHIFTIN(makeup + 0, data[0], dlci); 441 SHIFTIN(makeup + 1, data[1], dlci); 442 SHIFTIN(makeup + 3, data[2], dlci); /* 3 and 2 is correct */ 443 break; 444 case 4: 445 SHIFTIN(makeup + 0, data[0], dlci); 446 SHIFTIN(makeup + 1, data[1], dlci); 447 SHIFTIN(makeup + 2, data[2], dlci); 448 SHIFTIN(makeup + 3, data[3], dlci); 449 break; 450 default: 451 error = EINVAL; 452 goto out; 453 } 454 455 if (dlci > 1023) { 456 error = EINVAL; 457 goto out; 458 } 459 ctxnum = sc->ALT[dlci]; 460 if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) { 461 /* Send it */ 462 m_adj(m, alen); 463 NG_FWD_NEW_DATA(error, item, sc->channel[ctxnum].hook, m); 464 return (error); 465 } else { 466 error = ENETDOWN; 467 } 468 out: 469 NG_FREE_ITEM(item); 470 NG_FREE_M(m); 471 return (error); 472 } 473 474 /* 475 * Shutdown node 476 */ 477 static int 478 ngfrm_shutdown(node_p node) 479 { 480 const sc_p sc = NG_NODE_PRIVATE(node); 481 482 NG_NODE_SET_PRIVATE(node, NULL); 483 FREE(sc, M_NETGRAPH); 484 NG_NODE_UNREF(node); 485 return (0); 486 } 487 488 /* 489 * Hook disconnection 490 * 491 * Invalidate the private data associated with this dlci. 492 * For this type, removal of the last link resets tries to destroy the node. 493 */ 494 static int 495 ngfrm_disconnect(hook_p hook) 496 { 497 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 498 struct ctxinfo *const cp = NG_HOOK_PRIVATE(hook); 499 int dlci; 500 501 /* If it's a regular dlci hook, then free resources etc.. */ 502 if (cp != NULL) { 503 cp->hook = NULL; 504 dlci = cp->dlci; 505 if (dlci != -1) 506 sc->ALT[dlci] = 0; 507 cp->flags = 0; 508 sc->datahooks--; 509 } 510 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0) 511 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) 512 ng_rmnode_self(NG_HOOK_NODE(hook)); 513 return (0); 514 }
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