Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/netccitt/llc_input.c
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1 /* $NetBSD: llc_input.c,v 1.14 2005/02/26 22:45:10 perry Exp $ */ 2 3 /* 4 * Copyright (c) 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Dirk Husemann and the Computer Science Department (IV) of 9 * the University of Erlangen-Nuremberg, Germany. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)llc_input.c 8.1 (Berkeley) 6/10/93 36 */ 37 38 /* 39 * Copyright (c) 1990, 1991, 1992 40 * Dirk Husemann, Computer Science Department IV, 41 * University of Erlangen-Nuremberg, Germany. 42 * 43 * This code is derived from software contributed to Berkeley by 44 * Dirk Husemann and the Computer Science Department (IV) of 45 * the University of Erlangen-Nuremberg, Germany. 46 * 47 * Redistribution and use in source and binary forms, with or without 48 * modification, are permitted provided that the following conditions 49 * are met: 50 * 1. Redistributions of source code must retain the above copyright 51 * notice, this list of conditions and the following disclaimer. 52 * 2. Redistributions in binary form must reproduce the above copyright 53 * notice, this list of conditions and the following disclaimer in the 54 * documentation and/or other materials provided with the distribution. 55 * 3. All advertising materials mentioning features or use of this software 56 * must display the following acknowledgement: 57 * This product includes software developed by the University of 58 * California, Berkeley and its contributors. 59 * 4. Neither the name of the University nor the names of its contributors 60 * may be used to endorse or promote products derived from this software 61 * without specific prior written permission. 62 * 63 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 64 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 65 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 66 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 67 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 68 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 69 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 70 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 71 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 72 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 73 * SUCH DAMAGE. 74 * 75 * @(#)llc_input.c 8.1 (Berkeley) 6/10/93 76 */ 77 78 #include <sys/cdefs.h> 79 __KERNEL_RCSID(0, "$NetBSD: llc_input.c,v 1.14 2005/02/26 22:45:10 perry Exp $"); 80 81 #include <sys/param.h> 82 #include <sys/systm.h> 83 #include <sys/mbuf.h> 84 #include <sys/domain.h> 85 #include <sys/socket.h> 86 #include <sys/protosw.h> 87 #include <sys/errno.h> 88 #include <sys/time.h> 89 #include <sys/kernel.h> 90 91 #include <net/if.h> 92 #include <net/if_dl.h> 93 #include <net/if_llc.h> 94 #include <net/route.h> 95 96 #include <netccitt/dll.h> 97 #include <netccitt/llc_var.h> 98 99 #include <machine/stdarg.h> 100 101 struct ifqueue llcintrq; 102 103 /* 104 * This module implements LLC as specified by ISO 8802-2. 105 */ 106 107 108 /* 109 * llcintr() handles all LLC frames (except ISO CLNS ones for the time being) 110 * and tries to pass them on to the appropriate network layer entity. 111 */ 112 void 113 llcintr() 114 { 115 struct mbuf *m; 116 int i; 117 int frame_kind; 118 u_char cmdrsp; 119 struct llc_linkcb *linkp; 120 struct npaidbentry *sapinfo = NULL; 121 struct sdl_hdr *sdlhdr; 122 struct llc *frame; 123 long expected_len; 124 125 struct ifnet *ifp; 126 struct rtentry *llrt; 127 struct rtentry *nlrt; 128 129 for (;;) { 130 i = splnet(); 131 IF_DEQUEUE(&llcintrq, m); 132 splx(i); 133 if (m == 0) 134 break; 135 #ifdef DIAGNOSTIC 136 if ((m->m_flags & M_PKTHDR) == 0) 137 panic("llcintr no HDR"); 138 #endif 139 /* 140 * Get ifp this packet was received on 141 */ 142 ifp = m->m_pkthdr.rcvif; 143 144 sdlhdr = mtod(m, struct sdl_hdr *); 145 146 /* 147 * [Copied from net/ip_input.c] 148 * 149 * Check that the amount of data in the buffers is 150 * at least as much as the LLC header tells us. 151 * Trim mbufs if longer than expected. 152 * Drop packets if shorter than we think they are. 153 * 154 * Layout of mbuf chain at this point: 155 * 156 * +-------------------------------+----+ -\ 157 * | sockaddr_dl src - sdlhdr_src | 20 | \ 158 * +-------------------------------+----+ | 159 * | sockaddr_dl dst - sdlhdr_dst | 20 | > sizeof(struct sdl_hdr) == 44 160 * +-------------------------------+----+ | 161 * | LLC frame len - sdlhdr_len | 04 | / 162 * +-------------------------------+----+ -/ 163 * / 164 * | m_next 165 * \ 166 * +----------------------------+----+ -\ 167 * | llc DSAP | 01 | \ 168 * +----------------------------+----+ | 169 * | llc SSAP | 01 | | 170 * +----------------------------+----+ > sdlhdr_len 171 * | llc control | 01 | | 172 * +----------------------------+----+ | 173 * | ... | | / 174 * -/ 175 * 176 * Thus the we expect to have exactly 177 * (sdlhdr->sdlhdr_len+sizeof(struct sdl_hdr)) in the mbuf chain 178 */ 179 expected_len = sdlhdr->sdlhdr_len + sizeof(struct sdl_hdr); 180 181 if (m->m_pkthdr.len < expected_len) { 182 m_freem(m); 183 continue; 184 } 185 if (m->m_pkthdr.len > expected_len) { 186 if (m->m_len == m->m_pkthdr.len) { 187 m->m_len = expected_len; 188 m->m_pkthdr.len = expected_len; 189 } else 190 m_adj(m, expected_len - m->m_pkthdr.len); 191 } 192 193 /* 194 * Get llc header 195 */ 196 if (m->m_len > sizeof(struct sdl_hdr)) 197 frame = mtod((struct mbuf *)((struct sdl_hdr*)(m+1)), 198 struct llc *); 199 else frame = mtod(m->m_next, struct llc *); 200 if (frame == (struct llc *) NULL) 201 panic("llcintr no llc header"); 202 203 /* 204 * Now check for bogus I/S frame, i.e. those with a control 205 * field telling us they're an I/S frame yet their length 206 * is less than the established I/S frame length (DSAP + SSAP + 207 * control + N(R)&P/F = 4) --- we drop those suckers 208 */ 209 if (((frame->llc_control & 0x03) != 0x03) 210 && ((expected_len - sizeof(struct sdl_hdr)) < LLC_ISFRAMELEN)) { 211 m_freem(m); 212 printf("llc: hurz error\n"); 213 continue; 214 } 215 216 /* 217 * Get link control block for the addressed link connection. 218 * If there is none we take care of it later on. 219 */ 220 cmdrsp = (frame->llc_ssap & 0x01); 221 frame->llc_ssap &= ~0x01; 222 llrt = rtalloc1((struct sockaddr *)&sdlhdr->sdlhdr_src, 0); 223 if (llrt) 224 llrt->rt_refcnt--; 225 #ifdef notyet 226 else 227 llrt = npaidb_enter(&sdlhdr->sdlhdr_src, 0, 0, 0); 228 #endif /* notyet */ 229 else { 230 /* 231 * We cannot do anything currently here as we 232 * don't `know' this link --- drop it 233 */ 234 m_freem(m); 235 continue; 236 } 237 linkp = ((struct npaidbentry *)(llrt->rt_llinfo))->np_link; 238 nlrt = ((struct npaidbentry *)(llrt->rt_llinfo))->np_rt; 239 240 /* 241 * If the link is not existing right now, we can try and look up 242 * the SAP info block. 243 */ 244 if ((linkp == 0) && frame->llc_ssap) 245 sapinfo = llc_getsapinfo(frame->llc_dsap, ifp); 246 247 /* 248 * Handle XID and TEST frames 249 * XID: if DLSAP == 0, return type-of-services 250 * window-0 251 * DLSAP-0 252 * format-identifier-? 253 * if DLSAP != 0, locate sapcb and return 254 * type-of-services 255 * SAP-window 256 * format-identifier-? 257 * TEST: swap (snpah_dst, snpah_src) and return frame 258 * 259 * Also toggle the CMD/RESP bit 260 * 261 * Is this behaviour correct? Check ISO 8802-2 (90)! 262 */ 263 frame_kind = llc_decode(frame, (struct llc_linkcb *)0); 264 switch(frame_kind) { 265 case LLCFT_XID: 266 if (linkp || sapinfo) { 267 if (linkp) 268 frame->llc_window = linkp->llcl_window; 269 else frame->llc_window = sapinfo->si_window; 270 frame->llc_fid = 9; /* XXX */ 271 frame->llc_class = sapinfo->si_class; 272 frame->llc_ssap = frame->llc_dsap; 273 } else { 274 frame->llc_window = 0; 275 frame->llc_fid = 9; 276 frame->llc_class = 1; 277 frame->llc_dsap = frame->llc_ssap = 0; 278 } 279 280 /* fall thru to */ 281 case LLCFT_TEST: 282 sdl_swapaddr(&(mtod(m, struct sdl_hdr *)->sdlhdr_dst), 283 &(mtod(m, struct sdl_hdr *)->sdlhdr_src)); 284 285 /* Now set the CMD/RESP bit */ 286 frame->llc_ssap |= (cmdrsp == 0x0 ? 0x1 : 0x0); 287 288 /* Ship it out again */ 289 (*ifp->if_output)(ifp, m, 290 (struct sockaddr *) &(mtod(m, struct sdl_hdr *)->sdlhdr_dst), 291 (struct rtentry *) 0); 292 continue; 293 } 294 295 /* 296 * Create link control block in case it is not existing 297 */ 298 if (linkp == 0 && sapinfo) { 299 if ((linkp = llc_newlink(&sdlhdr->sdlhdr_src, ifp, nlrt, 300 (nlrt == 0) ? 0 : nlrt->rt_llinfo, 301 llrt)) == 0) { 302 printf("llcintr: couldn't create new link\n"); 303 m_freem(m); 304 continue; 305 } 306 ((struct npaidbentry *)llrt->rt_llinfo)->np_link = linkp; 307 } else if (linkp == 0) { 308 /* The link is not known to us, drop the frame and continue */ 309 m_freem(m); 310 continue; 311 } 312 313 /* 314 * Drop SNPA header and get rid of empty mbuf at the 315 * front of the mbuf chain (I don't like 'em) 316 */ 317 m_adj(m, sizeof(struct sdl_hdr)); 318 /* 319 * LLC_UFRAMELEN is sufficient, m_pullup() will pull up 320 * the min(m->m_len, maxprotohdr_len [=40]) thus doing 321 * the trick ... 322 */ 323 if ((m = m_pullup(m, LLC_UFRAMELEN))) 324 /* 325 * Pass it on thru the elements of procedure 326 */ 327 llc_input(m, linkp, cmdrsp); 328 } 329 return; 330 } 331 332 /* 333 * llc_input() --- We deal with the various incoming frames here. 334 * Basically we (indirectly) call the appropriate 335 * state handler function that's pointed to by 336 * llcl_statehandler. 337 * 338 * The statehandler returns an action code --- 339 * further actions like 340 * o notify network layer 341 * o block further sending 342 * o deblock link 343 * o ... 344 * are then enacted accordingly. 345 */ 346 int 347 llc_input(struct mbuf *m, ...) 348 { 349 int frame_kind; 350 int pollfinal; 351 int action = 0; 352 struct llc *frame; 353 struct llc_linkcb *linkp; 354 u_int cmdrsp; 355 va_list ap; 356 357 va_start(ap, m); 358 linkp = va_arg(ap, struct llc_linkcb *); 359 cmdrsp = va_arg(ap, u_int); 360 va_end(ap); 361 362 363 if ((frame = mtod(m, struct llc *)) == (struct llc *) 0) { 364 m_freem(m); 365 return 0; 366 } 367 pollfinal = ((frame->llc_control & 0x03) == 0x03) ? 368 LLCGBITS(frame->llc_control, u_pf) : 369 LLCGBITS(frame->llc_control_ext, s_pf); 370 371 /* 372 * first decode the frame 373 */ 374 frame_kind = llc_decode(frame, linkp); 375 376 switch (action = llc_statehandler(linkp, frame, frame_kind, cmdrsp, 377 pollfinal)) { 378 case LLC_DATA_INDICATION: 379 m_adj(m, LLC_ISFRAMELEN); 380 if ((m = m_pullup(m, NLHDRSIZEGUESS)) != NULL) { 381 m->m_pkthdr.rcvif = (struct ifnet *)linkp->llcl_nlnext; 382 (*linkp->llcl_sapinfo->si_input)(m, NULL, NULL, NULL); 383 } 384 break; 385 } 386 387 /* release mbuf if not an info frame */ 388 if (action != LLC_DATA_INDICATION && m) 389 m_freem(m); 390 391 /* try to get frames out ... */ 392 llc_start(linkp); 393 394 return 0; 395 } 396 397 /* 398 * This routine is called by configuration setup. It sets up a station control 399 * block and notifies all registered upper level protocols. 400 */ 401 void * 402 llc_ctlinput(prc, addr, info) 403 int prc; 404 struct sockaddr *addr; 405 void *info; 406 { 407 struct ifnet *ifp = NULL; 408 struct ifaddr *ifa; 409 struct dll_ctlinfo *ctlinfo = (struct dll_ctlinfo *)info; 410 u_char sap; 411 struct dllconfig *config; 412 caddr_t pcb; 413 struct rtentry *nlrt; 414 struct rtentry *llrt = NULL; 415 struct llc_linkcb *linkp = NULL; 416 int i; 417 418 /* info must point to something valid at all times */ 419 if (info == 0) 420 return 0; 421 422 if (prc == PRC_IFUP || prc == PRC_IFDOWN) { 423 /* we use either this set ... */ 424 ifa = ifa_ifwithaddr(addr); 425 if (ifa == NULL) 426 return (0); 427 ifp = ifa->ifa_ifp; 428 if (ifp == NULL) 429 return (0); 430 431 sap = ctlinfo->dlcti_lsap; 432 config = ctlinfo->dlcti_cfg; 433 pcb = (caddr_t) 0; 434 nlrt = (struct rtentry *) 0; 435 } else { 436 /* or this one */ 437 sap = 0; 438 config = (struct dllconfig *) 0; 439 pcb = ctlinfo->dlcti_pcb; 440 nlrt = ctlinfo->dlcti_rt; 441 442 if ((llrt = rtalloc1(nlrt->rt_gateway, 0))) 443 llrt->rt_refcnt--; 444 else return 0; 445 446 linkp = ((struct npaidbentry *)llrt->rt_llinfo)->np_link; 447 } 448 449 switch (prc) { 450 case PRC_IFUP: 451 (void) llc_setsapinfo(ifp, addr->sa_family, sap, config); 452 return 0; 453 454 case PRC_IFDOWN: { 455 struct llc_linkcb *linkp; 456 struct llc_linkcb *nlinkp; 457 int i; 458 459 /* 460 * All links are accessible over the doubly linked list llccb_q 461 */ 462 if (!LQEMPTY) { 463 /* 464 * A for-loop is not that great an idea as the linkp 465 * will get deleted by llc_timer() 466 */ 467 linkp = LQFIRST; 468 while (LQVALID(linkp)) { 469 nlinkp = LQNEXT(linkp); 470 if ((linkp->llcl_if = ifp) != NULL) { 471 i = splnet(); 472 (void)llc_statehandler(linkp, (struct llc *)0, 473 NL_DISCONNECT_REQUEST, 474 0, 1); 475 splx(i); 476 } 477 linkp = nlinkp; 478 } 479 } 480 } 481 482 case PRC_CONNECT_REQUEST: 483 if (linkp == 0) { 484 if ((linkp = llc_newlink((struct sockaddr_dl *) nlrt->rt_gateway, 485 nlrt->rt_ifp, nlrt, 486 pcb, llrt)) == 0) 487 return (0); 488 ((struct npaidbentry *)llrt->rt_llinfo)->np_link = linkp; 489 i = splnet(); 490 (void)llc_statehandler(linkp, (struct llc *) 0, 491 NL_CONNECT_REQUEST, 0, 1); 492 splx(i); 493 } 494 return ((caddr_t)linkp); 495 496 case PRC_DISCONNECT_REQUEST: 497 if (linkp == 0) 498 panic("no link control block!"); 499 500 i = splnet(); 501 (void)llc_statehandler(linkp, (struct llc *) 0, 502 NL_DISCONNECT_REQUEST, 0, 1); 503 splx(i); 504 505 /* 506 * The actual removal of the link control block is done by the 507 * cleaning neutrum (i.e. llc_timer()). 508 */ 509 break; 510 511 case PRC_RESET_REQUEST: 512 if (linkp == 0) 513 panic("no link control block!"); 514 515 i = splnet(); 516 (void)llc_statehandler(linkp, (struct llc *) 0, 517 NL_RESET_REQUEST, 0, 1); 518 splx(i); 519 520 break; 521 522 } 523 524 return 0; 525 }
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