ng_tty.c revision 134445
1 2/* 3 * ng_tty.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: Archie Cobbs <archie@freebsd.org> 38 * 39 * $FreeBSD: head/sys/netgraph/ng_tty.c 134445 2004-08-28 15:24:53Z rwatson $ 40 * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $ 41 */ 42 43/* 44 * This file implements a terminal line discipline that is also a 45 * netgraph node. Installing this line discipline on a terminal device 46 * instantiates a new netgraph node of this type, which allows access 47 * to the device via the "hook" hook of the node. 48 * 49 * Once the line discipline is installed, you can find out the name 50 * of the corresponding netgraph node via a NGIOCGINFO ioctl(). 51 * 52 * Incoming characters are delievered to the hook one at a time, each 53 * in its own mbuf. You may optionally define a ``hotchar,'' which causes 54 * incoming characters to be buffered up until either the hotchar is 55 * seen or the mbuf is full (MHLEN bytes). Then all buffered characters 56 * are immediately delivered. 57 * 58 * NOTE: This node operates at spltty(). 59 */ 60 61#include <sys/param.h> 62#include <sys/systm.h> 63#include <sys/kernel.h> 64#include <sys/conf.h> 65#include <sys/mbuf.h> 66#include <sys/malloc.h> 67#include <sys/fcntl.h> 68#include <sys/tty.h> 69#include <sys/ttycom.h> 70#include <sys/syslog.h> 71#include <sys/errno.h> 72#include <sys/ioccom.h> 73 74#include <netgraph/ng_message.h> 75#include <netgraph/netgraph.h> 76#include <netgraph/ng_tty.h> 77 78NET_NEEDS_GIANT("ng_tty"); 79 80/* Misc defs */ 81#define MAX_MBUFQ 3 /* Max number of queued mbufs */ 82#define NGT_HIWATER 400 /* High water mark on output */ 83 84/* Per-node private info */ 85struct ngt_sc { 86 struct tty *tp; /* Terminal device */ 87 node_p node; /* Netgraph node */ 88 hook_p hook; /* Netgraph hook */ 89 struct mbuf *m; /* Incoming data buffer */ 90 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */ 91 short qlen; /* Length of queue */ 92 short hotchar; /* Hotchar, or -1 if none */ 93 u_int flags; /* Flags */ 94 struct callout_handle chand; /* See man timeout(9) */ 95}; 96typedef struct ngt_sc *sc_p; 97 98/* Flags */ 99#define FLG_TIMEOUT 0x0001 /* A timeout is pending */ 100#define FLG_DEBUG 0x0002 101 102/* Debugging */ 103#ifdef INVARIANTS 104#define QUEUECHECK(sc) \ 105 do { \ 106 struct mbuf **mp; \ 107 int k; \ 108 \ 109 for (k = 0, mp = &sc->qhead; \ 110 k <= MAX_MBUFQ && *mp; \ 111 k++, mp = &(*mp)->m_nextpkt); \ 112 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \ 113 panic("%s: queue", __func__); \ 114 } while (0) 115#else 116#define QUEUECHECK(sc) do {} while (0) 117#endif 118 119/* Line discipline methods */ 120static int ngt_open(struct cdev *dev, struct tty *tp); 121static int ngt_close(struct tty *tp, int flag); 122static int ngt_read(struct tty *tp, struct uio *uio, int flag); 123static int ngt_write(struct tty *tp, struct uio *uio, int flag); 124static int ngt_tioctl(struct tty *tp, 125 u_long cmd, caddr_t data, int flag, struct thread *); 126static int ngt_input(int c, struct tty *tp); 127static int ngt_start(struct tty *tp); 128 129/* Netgraph methods */ 130static ng_constructor_t ngt_constructor; 131static ng_rcvmsg_t ngt_rcvmsg; 132static ng_shutdown_t ngt_shutdown; 133static ng_newhook_t ngt_newhook; 134static ng_connect_t ngt_connect; 135static ng_rcvdata_t ngt_rcvdata; 136static ng_disconnect_t ngt_disconnect; 137static int ngt_mod_event(module_t mod, int event, void *data); 138 139/* Other stuff */ 140static void ngt_timeout(void *arg); 141 142#define ERROUT(x) do { error = (x); goto done; } while (0) 143 144/* Line discipline descriptor */ 145static struct linesw ngt_disc = { 146 ngt_open, 147 ngt_close, 148 ngt_read, 149 ngt_write, 150 ngt_tioctl, 151 ngt_input, 152 ngt_start, 153 ttymodem 154}; 155 156/* Netgraph node type descriptor */ 157static struct ng_type typestruct = { 158 .version = NG_ABI_VERSION, 159 .name = NG_TTY_NODE_TYPE, 160 .mod_event = ngt_mod_event, 161 .constructor = ngt_constructor, 162 .rcvmsg = ngt_rcvmsg, 163 .shutdown = ngt_shutdown, 164 .newhook = ngt_newhook, 165 .connect = ngt_connect, 166 .rcvdata = ngt_rcvdata, 167 .disconnect = ngt_disconnect, 168}; 169NETGRAPH_INIT(tty, &typestruct); 170 171/* 172 * XXXRW: ngt_unit is protected by ng_tty_mtx. ngt_ldisc is constant once 173 * ng_tty is initialized. ngt_nodeop_ok is untouched, and might want to be a 174 * sleep lock in the future? 175 */ 176static int ngt_unit; 177static int ngt_nodeop_ok; /* OK to create/remove node */ 178static int ngt_ldisc; 179 180static struct mtx ng_tty_mtx; 181MTX_SYSINIT(ng_tty, &ng_tty_mtx, "ng_tty", MTX_DEF); 182 183/****************************************************************** 184 LINE DISCIPLINE METHODS 185******************************************************************/ 186 187/* 188 * Set our line discipline on the tty. 189 * Called from device open routine or ttioctl() at >= splsofttty() 190 */ 191static int 192ngt_open(struct cdev *dev, struct tty *tp) 193{ 194 struct thread *const td = curthread; /* XXX */ 195 char name[sizeof(NG_TTY_NODE_TYPE) + 8]; 196 sc_p sc; 197 int s, error; 198 199 /* Super-user only */ 200 if ((error = suser(td))) 201 return (error); 202 s = splnet(); 203 (void) spltty(); /* XXX is this necessary? */ 204 205 tp->t_hotchar = NG_TTY_DFL_HOTCHAR; 206 207 /* Initialize private struct */ 208 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO); 209 if (sc == NULL) { 210 error = ENOMEM; 211 goto done; 212 } 213 sc->tp = tp; 214 sc->hotchar = NG_TTY_DFL_HOTCHAR; 215 sc->qtail = &sc->qhead; 216 QUEUECHECK(sc); 217 callout_handle_init(&sc->chand); 218 219 /* Setup netgraph node */ 220 ngt_nodeop_ok = 1; 221 error = ng_make_node_common(&typestruct, &sc->node); 222 ngt_nodeop_ok = 0; 223 if (error) { 224 FREE(sc, M_NETGRAPH); 225 goto done; 226 } 227 mtx_lock(&ng_tty_mtx); 228 snprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++); 229 mtx_unlock(&ng_tty_mtx); 230 231 /* Assign node its name */ 232 if ((error = ng_name_node(sc->node, name))) { 233 log(LOG_ERR, "%s: node name exists?\n", name); 234 ngt_nodeop_ok = 1; 235 NG_NODE_UNREF(sc->node); 236 ngt_nodeop_ok = 0; 237 goto done; 238 } 239 240 /* Set back pointers */ 241 NG_NODE_SET_PRIVATE(sc->node, sc); 242 tp->t_sc = (caddr_t) sc; 243 244 /* 245 * Pre-allocate cblocks to the an appropriate amount. 246 * I'm not sure what is appropriate. 247 */ 248 ttyflush(tp, FREAD | FWRITE); 249 clist_alloc_cblocks(&tp->t_canq, 0, 0); 250 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 251 clist_alloc_cblocks(&tp->t_outq, 252 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER); 253 254done: 255 /* Done */ 256 splx(s); 257 return (error); 258} 259 260/* 261 * Line specific close routine, called from device close routine 262 * and from ttioctl at >= splsofttty(). This causes the node to 263 * be destroyed as well. 264 */ 265static int 266ngt_close(struct tty *tp, int flag) 267{ 268 const sc_p sc = (sc_p) tp->t_sc; 269 int s; 270 271 s = spltty(); 272 ttyflush(tp, FREAD | FWRITE); 273 clist_free_cblocks(&tp->t_outq); 274 if (sc != NULL) { 275 if (sc->flags & FLG_TIMEOUT) { 276 untimeout(ngt_timeout, sc, sc->chand); 277 sc->flags &= ~FLG_TIMEOUT; 278 } 279 ngt_nodeop_ok = 1; 280 ng_rmnode_self(sc->node); 281 ngt_nodeop_ok = 0; 282 tp->t_sc = NULL; 283 } 284 splx(s); 285 return (0); 286} 287 288/* 289 * Once the device has been turned into a node, we don't allow reading. 290 */ 291static int 292ngt_read(struct tty *tp, struct uio *uio, int flag) 293{ 294 return (EIO); 295} 296 297/* 298 * Once the device has been turned into a node, we don't allow writing. 299 */ 300static int 301ngt_write(struct tty *tp, struct uio *uio, int flag) 302{ 303 return (EIO); 304} 305 306/* 307 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 308 */ 309static int 310ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct thread *td) 311{ 312 const sc_p sc = (sc_p) tp->t_sc; 313 int s, error = 0; 314 315 s = spltty(); 316 switch (cmd) { 317 case NGIOCGINFO: 318 { 319 struct nodeinfo *const ni = (struct nodeinfo *) data; 320 const node_p node = sc->node; 321 322 bzero(ni, sizeof(*ni)); 323 if (NG_NODE_HAS_NAME(node)) 324 strncpy(ni->name, NG_NODE_NAME(node), sizeof(ni->name) - 1); 325 strncpy(ni->type, node->nd_type->name, sizeof(ni->type) - 1); 326 ni->id = (u_int32_t) ng_node2ID(node); 327 ni->hooks = NG_NODE_NUMHOOKS(node); 328 break; 329 } 330 default: 331 ERROUT(ENOIOCTL); 332 } 333done: 334 splx(s); 335 return (error); 336} 337 338/* 339 * Receive data coming from the device. We get one character at 340 * a time, which is kindof silly. 341 * Only guaranteed to be at splsofttty() or spltty(). 342 */ 343static int 344ngt_input(int c, struct tty *tp) 345{ 346 const sc_p sc = (sc_p) tp->t_sc; 347 const node_p node = sc->node; 348 struct mbuf *m; 349 int s, error = 0; 350 351 if (!sc || tp != sc->tp) 352 return (0); 353 s = spltty(); 354 if (!sc->hook) 355 ERROUT(0); 356 357 /* Check for error conditions */ 358 if ((tp->t_state & TS_CONNECTED) == 0) { 359 if (sc->flags & FLG_DEBUG) 360 log(LOG_DEBUG, "%s: no carrier\n", NG_NODE_NAME(node)); 361 ERROUT(0); 362 } 363 if (c & TTY_ERRORMASK) { 364 /* framing error or overrun on this char */ 365 if (sc->flags & FLG_DEBUG) 366 log(LOG_DEBUG, "%s: line error %x\n", 367 NG_NODE_NAME(node), c & TTY_ERRORMASK); 368 ERROUT(0); 369 } 370 c &= TTY_CHARMASK; 371 372 /* Get a new header mbuf if we need one */ 373 if (!(m = sc->m)) { 374 MGETHDR(m, M_DONTWAIT, MT_DATA); 375 if (!m) { 376 if (sc->flags & FLG_DEBUG) 377 log(LOG_ERR, 378 "%s: can't get mbuf\n", NG_NODE_NAME(node)); 379 ERROUT(ENOBUFS); 380 } 381 m->m_len = m->m_pkthdr.len = 0; 382 m->m_pkthdr.rcvif = NULL; 383 sc->m = m; 384 } 385 386 /* Add char to mbuf */ 387 *mtod(m, u_char *) = c; 388 m->m_data++; 389 m->m_len++; 390 m->m_pkthdr.len++; 391 392 /* Ship off mbuf if it's time */ 393 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 394 m->m_data = m->m_pktdat; 395 NG_SEND_DATA_ONLY(error, sc->hook, m); 396 sc->m = NULL; 397 } 398done: 399 splx(s); 400 return (error); 401} 402 403/* 404 * This is called when the device driver is ready for more output. 405 * Called from tty system at splsofttty() or spltty(). 406 * Also call from ngt_rcv_data() when a new mbuf is available for output. 407 */ 408static int 409ngt_start(struct tty *tp) 410{ 411 const sc_p sc = (sc_p) tp->t_sc; 412 int s; 413 414 s = spltty(); 415 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 416 struct mbuf *m = sc->qhead; 417 418 /* Remove first mbuf from queue */ 419 if (!m) 420 break; 421 if ((sc->qhead = m->m_nextpkt) == NULL) 422 sc->qtail = &sc->qhead; 423 sc->qlen--; 424 QUEUECHECK(sc); 425 426 /* Send as much of it as possible */ 427 while (m) { 428 int sent; 429 430 sent = m->m_len 431 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq); 432 m->m_data += sent; 433 m->m_len -= sent; 434 if (m->m_len > 0) 435 break; /* device can't take no more */ 436 m = m_free(m); 437 } 438 439 /* Put remainder of mbuf chain (if any) back on queue */ 440 if (m) { 441 m->m_nextpkt = sc->qhead; 442 sc->qhead = m; 443 if (sc->qtail == &sc->qhead) 444 sc->qtail = &m->m_nextpkt; 445 sc->qlen++; 446 QUEUECHECK(sc); 447 break; 448 } 449 } 450 451 /* Call output process whether or not there is any output. We are 452 * being called in lieu of ttstart and must do what it would. */ 453 if (tp->t_oproc != NULL) 454 (*tp->t_oproc) (tp); 455 456 /* This timeout is needed for operation on a pseudo-tty, because the 457 * pty code doesn't call pppstart after it has drained the t_outq. */ 458 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 459 sc->chand = timeout(ngt_timeout, sc, 1); 460 sc->flags |= FLG_TIMEOUT; 461 } 462 splx(s); 463 return (0); 464} 465 466/* 467 * We still have data to output to the device, so try sending more. 468 */ 469static void 470ngt_timeout(void *arg) 471{ 472 const sc_p sc = (sc_p) arg; 473 int s; 474 475 s = spltty(); 476 sc->flags &= ~FLG_TIMEOUT; 477 ngt_start(sc->tp); 478 splx(s); 479} 480 481/****************************************************************** 482 NETGRAPH NODE METHODS 483******************************************************************/ 484 485/* 486 * Initialize a new node of this type. 487 * 488 * We only allow nodes to be created as a result of setting 489 * the line discipline on a tty, so always return an error if not. 490 */ 491static int 492ngt_constructor(node_p node) 493{ 494 return (EOPNOTSUPP); 495} 496 497/* 498 * Add a new hook. There can only be one. 499 */ 500static int 501ngt_newhook(node_p node, hook_p hook, const char *name) 502{ 503 const sc_p sc = NG_NODE_PRIVATE(node); 504 int s, error = 0; 505 506 if (strcmp(name, NG_TTY_HOOK)) 507 return (EINVAL); 508 s = spltty(); 509 if (sc->hook) 510 ERROUT(EISCONN); 511 sc->hook = hook; 512done: 513 splx(s); 514 return (error); 515} 516 517/* 518 * Set the hooks into queueing mode (for outgoing packets) 519 * Force single client at a time. 520 */ 521static int 522ngt_connect(hook_p hook) 523{ 524 /*NG_HOOK_FORCE_WRITER(hook); 525 NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));*/ 526 return (0); 527} 528 529/* 530 * Disconnect the hook 531 */ 532static int 533ngt_disconnect(hook_p hook) 534{ 535 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 536 int s; 537 538 s = spltty(); 539 if (hook != sc->hook) 540 panic(__func__); 541 sc->hook = NULL; 542 m_freem(sc->m); 543 sc->m = NULL; 544 splx(s); 545 return (0); 546} 547 548/* 549 * Remove this node. The does the netgraph portion of the shutdown. 550 * This should only be called indirectly from ngt_close(). 551 */ 552static int 553ngt_shutdown(node_p node) 554{ 555 const sc_p sc = NG_NODE_PRIVATE(node); 556 557 if (!ngt_nodeop_ok) 558 return (EOPNOTSUPP); 559 NG_NODE_SET_PRIVATE(node, NULL); 560 NG_NODE_UNREF(sc->node); 561 m_freem(sc->qhead); 562 m_freem(sc->m); 563 bzero(sc, sizeof(*sc)); 564 FREE(sc, M_NETGRAPH); 565 return (0); 566} 567 568/* 569 * Receive incoming data from netgraph system. Put it on our 570 * output queue and start output if necessary. 571 */ 572static int 573ngt_rcvdata(hook_p hook, item_p item) 574{ 575 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 576 int s, error = 0; 577 struct mbuf *m; 578 579 if (hook != sc->hook) 580 panic(__func__); 581 582 NGI_GET_M(item, m); 583 NG_FREE_ITEM(item); 584 s = spltty(); 585 if (sc->qlen >= MAX_MBUFQ) 586 ERROUT(ENOBUFS); 587 m->m_nextpkt = NULL; 588 *sc->qtail = m; 589 sc->qtail = &m->m_nextpkt; 590 sc->qlen++; 591 QUEUECHECK(sc); 592 m = NULL; 593 if (sc->qlen == 1) 594 ngt_start(sc->tp); 595done: 596 splx(s); 597 if (m) 598 m_freem(m); 599 return (error); 600} 601 602/* 603 * Receive control message 604 */ 605static int 606ngt_rcvmsg(node_p node, item_p item, hook_p lasthook) 607{ 608 const sc_p sc = NG_NODE_PRIVATE(node); 609 struct ng_mesg *resp = NULL; 610 int error = 0; 611 struct ng_mesg *msg; 612 613 NGI_GET_MSG(item, msg); 614 switch (msg->header.typecookie) { 615 case NGM_TTY_COOKIE: 616 switch (msg->header.cmd) { 617 case NGM_TTY_SET_HOTCHAR: 618 { 619 int hotchar; 620 621 if (msg->header.arglen != sizeof(int)) 622 ERROUT(EINVAL); 623 hotchar = *((int *) msg->data); 624 if (hotchar != (u_char) hotchar && hotchar != -1) 625 ERROUT(EINVAL); 626 sc->hotchar = hotchar; /* race condition is OK */ 627 break; 628 } 629 case NGM_TTY_GET_HOTCHAR: 630 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 631 if (!resp) 632 ERROUT(ENOMEM); 633 /* Race condition here is OK */ 634 *((int *) resp->data) = sc->hotchar; 635 break; 636 default: 637 ERROUT(EINVAL); 638 } 639 break; 640 default: 641 ERROUT(EINVAL); 642 } 643done: 644 NG_RESPOND_MSG(error, node, item, resp); 645 NG_FREE_MSG(msg); 646 return (error); 647} 648 649/****************************************************************** 650 INITIALIZATION 651******************************************************************/ 652 653/* 654 * Handle loading and unloading for this node type 655 */ 656static int 657ngt_mod_event(module_t mod, int event, void *data) 658{ 659 /* struct ng_type *const type = data;*/ 660 int s, error = 0; 661 662 switch (event) { 663 case MOD_LOAD: 664 665 /* Register line discipline */ 666 s = spltty(); 667 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 668 splx(s); 669 log(LOG_ERR, "%s: can't register line discipline", 670 __func__); 671 return (EIO); 672 } 673 splx(s); 674 break; 675 676 case MOD_UNLOAD: 677 678 /* Unregister line discipline */ 679 s = spltty(); 680 ldisc_deregister(ngt_ldisc); 681 splx(s); 682 break; 683 684 default: 685 error = EOPNOTSUPP; 686 break; 687 } 688 return (error); 689} 690 691