1 /* 2 * (MPSAFE) 3 * 4 * ng_tty.c 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: Archie Cobbs <archie@freebsd.org> 39 * 40 * $FreeBSD: src/sys/netgraph/ng_tty.c,v 1.7.2.3 2002/02/13 00:43:12 dillon Exp $ 41 * $DragonFly: src/sys/netgraph/tty/ng_tty.c,v 1.19 2008/01/06 16:55:52 swildner Exp $ 42 * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $ 43 */ 44 45 /* 46 * This file implements a terminal line discipline that is also a 47 * netgraph node. Installing this line discipline on a terminal device 48 * instantiates a new netgraph node of this type, which allows access 49 * to the device via the "hook" hook of the node. 50 * 51 * Once the line discipline is installed, you can find out the name 52 * of the corresponding netgraph node via a NGIOCGINFO ioctl(). 53 * 54 * Incoming characters are delievered to the hook one at a time, each 55 * in its own mbuf. You may optionally define a ``hotchar,'' which causes 56 * incoming characters to be buffered up until either the hotchar is 57 * seen or the mbuf is full (MHLEN bytes). Then all buffered characters 58 * are immediately delivered. 59 * 60 * NOTE: This node operates at spltty(). 61 */ 62 63 #include <sys/param.h> 64 #include <sys/systm.h> 65 #include <sys/kernel.h> 66 #include <sys/conf.h> 67 #include <sys/proc.h> 68 #include <sys/priv.h> 69 #include <sys/mbuf.h> 70 #include <sys/malloc.h> 71 #include <sys/fcntl.h> 72 #include <sys/tty.h> 73 #include <sys/ttycom.h> 74 #include <sys/syslog.h> 75 #include <sys/errno.h> 76 #include <sys/thread2.h> 77 78 #include <netgraph/ng_message.h> 79 #include <netgraph/netgraph.h> 80 #include "ng_tty.h" 81 82 /* Misc defs */ 83 #define MAX_MBUFQ 3 /* Max number of queued mbufs */ 84 #define NGT_HIWATER 400 /* High water mark on output */ 85 86 /* Per-node private info */ 87 struct ngt_sc { 88 struct tty *tp; /* Terminal device */ 89 node_p node; /* Netgraph node */ 90 hook_p hook; /* Netgraph hook */ 91 struct mbuf *m; /* Incoming data buffer */ 92 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */ 93 short qlen; /* Length of queue */ 94 short hotchar; /* Hotchar, or -1 if none */ 95 u_int flags; /* Flags */ 96 struct callout ctimeout; /* See man timeout(9) */ 97 }; 98 typedef struct ngt_sc *sc_p; 99 100 /* Flags */ 101 #define FLG_TIMEOUT 0x0001 /* A timeout is pending */ 102 #define FLG_DEBUG 0x0002 103 104 /* Debugging */ 105 #ifdef INVARIANTS 106 #define QUEUECHECK(sc) \ 107 do { \ 108 struct mbuf **mp; \ 109 int k; \ 110 \ 111 for (k = 0, mp = &sc->qhead; \ 112 k <= MAX_MBUFQ && *mp; \ 113 k++, mp = &(*mp)->m_nextpkt); \ 114 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \ 115 panic("%s: queue", __func__); \ 116 } while (0) 117 #else 118 #define QUEUECHECK(sc) do {} while (0) 119 #endif 120 121 /* Line discipline methods */ 122 static int ngt_open(cdev_t dev, struct tty *tp); 123 static int ngt_close(struct tty *tp, int flag); 124 static int ngt_read(struct tty *tp, struct uio *uio, int flag); 125 static int ngt_write(struct tty *tp, struct uio *uio, int flag); 126 static int ngt_tioctl(struct tty *tp, 127 u_long cmd, caddr_t data, int flag, struct ucred *cred); 128 static int ngt_input(int c, struct tty *tp); 129 static int ngt_start(struct tty *tp); 130 131 /* Netgraph methods */ 132 static ng_constructor_t ngt_constructor; 133 static ng_rcvmsg_t ngt_rcvmsg; 134 static ng_shutdown_t ngt_shutdown; 135 static ng_newhook_t ngt_newhook; 136 static ng_rcvdata_t ngt_rcvdata; 137 static ng_disconnect_t ngt_disconnect; 138 static int ngt_mod_event(module_t mod, int event, void *data); 139 140 /* Other stuff */ 141 static void ngt_timeout(void *arg); 142 143 #define ERROUT(x) do { error = (x); goto done; } while (0) 144 145 /* Line discipline descriptor */ 146 static struct linesw ngt_disc = { 147 ngt_open, 148 ngt_close, 149 ngt_read, 150 ngt_write, 151 ngt_tioctl, 152 ngt_input, 153 ngt_start, 154 ttymodem, 155 NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */ 156 }; 157 158 /* Netgraph node type descriptor */ 159 static struct ng_type typestruct = { 160 NG_VERSION, 161 NG_TTY_NODE_TYPE, 162 ngt_mod_event, 163 ngt_constructor, 164 ngt_rcvmsg, 165 ngt_shutdown, 166 ngt_newhook, 167 NULL, 168 NULL, 169 ngt_rcvdata, 170 ngt_rcvdata, 171 ngt_disconnect, 172 NULL 173 }; 174 NETGRAPH_INIT(tty, &typestruct); 175 176 static int ngt_unit; 177 static int ngt_nodeop_ok; /* OK to create/remove node */ 178 static int ngt_ldisc; 179 180 /****************************************************************** 181 LINE DISCIPLINE METHODS 182 ******************************************************************/ 183 184 /* 185 * Set our line discipline on the tty. 186 * Called from device open routine or ttioctl() at >= splsofttty() 187 */ 188 static int 189 ngt_open(cdev_t dev, struct tty *tp) 190 { 191 struct thread *td = curthread; /* XXX */ 192 char name[sizeof(NG_TTY_NODE_TYPE) + 8]; 193 sc_p sc; 194 int error; 195 196 /* Super-user only */ 197 if ((error = priv_check(td, PRIV_ROOT))) 198 return (error); 199 crit_enter(); 200 lwkt_gettoken(&tty_token); 201 202 /* Already installed? */ 203 if (tp->t_line == NETGRAPHDISC) { 204 sc = (sc_p) tp->t_sc; 205 if (sc != NULL && sc->tp == tp) 206 goto done; 207 } 208 209 /* Initialize private struct */ 210 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO); 211 sc->tp = tp; 212 sc->hotchar = NG_TTY_DFL_HOTCHAR; 213 sc->qtail = &sc->qhead; 214 QUEUECHECK(sc); 215 callout_init_mp(&sc->ctimeout); 216 217 /* Setup netgraph node */ 218 ngt_nodeop_ok = 1; 219 error = ng_make_node_common(&typestruct, &sc->node); 220 ngt_nodeop_ok = 0; 221 if (error) { 222 FREE(sc, M_NETGRAPH); 223 goto done; 224 } 225 ksnprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++); 226 227 /* Set back pointers */ 228 sc->node->private = sc; 229 tp->t_sc = (caddr_t) sc; 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_rmnode(sc->node); 236 ngt_nodeop_ok = 0; 237 goto done; 238 } 239 240 /* 241 * Pre-allocate cblocks to the an appropriate amount. 242 * I'm not sure what is appropriate. 243 */ 244 ttyflush(tp, FREAD | FWRITE); 245 clist_alloc_cblocks(&tp->t_canq, 0, 0); 246 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 247 clist_alloc_cblocks(&tp->t_outq, 248 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER); 249 250 done: 251 /* Done */ 252 lwkt_reltoken(&tty_token); 253 crit_exit(); 254 return (error); 255 } 256 257 /* 258 * Line specific close routine, called from device close routine 259 * and from ttioctl at >= splsofttty(). This causes the node to 260 * be destroyed as well. 261 */ 262 static int 263 ngt_close(struct tty *tp, int flag) 264 { 265 const sc_p sc = (sc_p) tp->t_sc; 266 267 crit_enter(); 268 lwkt_gettoken(&tty_token); 269 ttyflush(tp, FREAD | FWRITE); 270 clist_free_cblocks(&tp->t_outq); 271 tp->t_line = 0; 272 if (sc != NULL) { 273 if (sc->flags & FLG_TIMEOUT) { 274 callout_stop(&sc->ctimeout); 275 sc->flags &= ~FLG_TIMEOUT; 276 } 277 ngt_nodeop_ok = 1; 278 ng_rmnode(sc->node); 279 ngt_nodeop_ok = 0; 280 tp->t_sc = NULL; 281 } 282 lwkt_reltoken(&tty_token); 283 crit_exit(); 284 return (0); 285 } 286 287 /* 288 * Once the device has been turned into a node, we don't allow reading. 289 */ 290 static int 291 ngt_read(struct tty *tp, struct uio *uio, int flag) 292 { 293 return (EIO); 294 } 295 296 /* 297 * Once the device has been turned into a node, we don't allow writing. 298 */ 299 static int 300 ngt_write(struct tty *tp, struct uio *uio, int flag) 301 { 302 return (EIO); 303 } 304 305 /* 306 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 307 */ 308 static int 309 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred) 310 { 311 const sc_p sc = (sc_p) tp->t_sc; 312 int error = 0; 313 314 crit_enter(); 315 lwkt_gettoken(&tty_token); 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 (node->name) 324 strncpy(ni->name, node->name, sizeof(ni->name) - 1); 325 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1); 326 ni->id = (u_int32_t)(uintptr_t)node; 327 ni->hooks = node->numhooks; 328 break; 329 } 330 default: 331 ERROUT(ENOIOCTL); 332 } 333 done: 334 lwkt_reltoken(&tty_token); 335 crit_exit(); 336 return (error); 337 } 338 339 /* 340 * Receive data coming from the device. We get one character at 341 * a time, which is kindof silly. 342 * Only guaranteed to be at splsofttty() or spltty(). 343 */ 344 static int 345 ngt_input(int c, struct tty *tp) 346 { 347 const sc_p sc = (sc_p) tp->t_sc; 348 const node_p node = sc->node; 349 struct mbuf *m; 350 int error = 0; 351 352 lwkt_gettoken(&tty_token); 353 if (!sc || tp != sc->tp) { 354 lwkt_reltoken(&tty_token); 355 return (0); 356 } 357 crit_enter(); 358 if (!sc->hook) 359 ERROUT(0); 360 361 /* Check for error conditions */ 362 if ((tp->t_state & TS_CONNECTED) == 0) { 363 if (sc->flags & FLG_DEBUG) 364 log(LOG_DEBUG, "%s: no carrier\n", node->name); 365 ERROUT(0); 366 } 367 if (c & TTY_ERRORMASK) { 368 /* framing error or overrun on this char */ 369 if (sc->flags & FLG_DEBUG) 370 log(LOG_DEBUG, "%s: line error %x\n", 371 node->name, c & TTY_ERRORMASK); 372 ERROUT(0); 373 } 374 c &= TTY_CHARMASK; 375 376 /* Get a new header mbuf if we need one */ 377 if (!(m = sc->m)) { 378 MGETHDR(m, MB_DONTWAIT, MT_DATA); 379 if (!m) { 380 if (sc->flags & FLG_DEBUG) 381 log(LOG_ERR, 382 "%s: can't get mbuf\n", node->name); 383 ERROUT(ENOBUFS); 384 } 385 m->m_len = m->m_pkthdr.len = 0; 386 m->m_pkthdr.rcvif = NULL; 387 sc->m = m; 388 } 389 390 /* Add char to mbuf */ 391 *mtod(m, u_char *) = c; 392 m->m_data++; 393 m->m_len++; 394 m->m_pkthdr.len++; 395 396 /* Ship off mbuf if it's time */ 397 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 398 m->m_data = m->m_pktdat; 399 error = ng_queue_data(sc->hook, m, NULL); 400 sc->m = NULL; 401 } 402 done: 403 crit_exit(); 404 lwkt_reltoken(&tty_token); 405 return (error); 406 } 407 408 /* 409 * This is called when the device driver is ready for more output. 410 * Called from tty system at splsofttty() or spltty(). 411 * Also call from ngt_rcv_data() when a new mbuf is available for output. 412 */ 413 static int 414 ngt_start(struct tty *tp) 415 { 416 const sc_p sc = (sc_p) tp->t_sc; 417 418 crit_enter(); 419 lwkt_gettoken(&tty_token); 420 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 421 struct mbuf *m = sc->qhead; 422 423 /* Remove first mbuf from queue */ 424 if (!m) 425 break; 426 if ((sc->qhead = m->m_nextpkt) == NULL) 427 sc->qtail = &sc->qhead; 428 sc->qlen--; 429 QUEUECHECK(sc); 430 431 /* Send as much of it as possible */ 432 while (m) { 433 int sent; 434 435 sent = m->m_len 436 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq); 437 m->m_data += sent; 438 m->m_len -= sent; 439 if (m->m_len > 0) 440 break; /* device can't take no more */ 441 m = m_free(m); 442 } 443 444 /* Put remainder of mbuf chain (if any) back on queue */ 445 if (m) { 446 m->m_nextpkt = sc->qhead; 447 sc->qhead = m; 448 if (sc->qtail == &sc->qhead) 449 sc->qtail = &m->m_nextpkt; 450 sc->qlen++; 451 QUEUECHECK(sc); 452 break; 453 } 454 } 455 456 /* Call output process whether or not there is any output. We are 457 * being called in lieu of ttstart and must do what it would. */ 458 if (tp->t_oproc != NULL) 459 (*tp->t_oproc) (tp); 460 461 /* This timeout is needed for operation on a pseudo-tty, because the 462 * pty code doesn't call pppstart after it has drained the t_outq. */ 463 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 464 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc); 465 sc->flags |= FLG_TIMEOUT; 466 } 467 lwkt_reltoken(&tty_token); 468 crit_exit(); 469 return (0); 470 } 471 472 /* 473 * We still have data to output to the device, so try sending more. 474 */ 475 static void 476 ngt_timeout(void *arg) 477 { 478 const sc_p sc = (sc_p) arg; 479 480 crit_enter(); 481 lwkt_gettoken(&tty_token); 482 sc->flags &= ~FLG_TIMEOUT; 483 ngt_start(sc->tp); 484 lwkt_reltoken(&tty_token); 485 crit_exit(); 486 } 487 488 /****************************************************************** 489 NETGRAPH NODE METHODS 490 ******************************************************************/ 491 492 /* 493 * Initialize a new node of this type. 494 * 495 * We only allow nodes to be created as a result of setting 496 * the line discipline on a tty, so always return an error if not. 497 */ 498 static int 499 ngt_constructor(node_p *nodep) 500 { 501 if (!ngt_nodeop_ok) 502 return (EOPNOTSUPP); 503 return (ng_make_node_common(&typestruct, nodep)); 504 } 505 506 /* 507 * Add a new hook. There can only be one. 508 */ 509 static int 510 ngt_newhook(node_p node, hook_p hook, const char *name) 511 { 512 const sc_p sc = node->private; 513 int error = 0; 514 515 if (strcmp(name, NG_TTY_HOOK)) 516 return (EINVAL); 517 crit_enter(); 518 lwkt_gettoken(&tty_token); 519 if (sc->hook) 520 ERROUT(EISCONN); 521 sc->hook = hook; 522 done: 523 lwkt_reltoken(&tty_token); 524 crit_exit(); 525 return (error); 526 } 527 528 /* 529 * Disconnect the hook 530 */ 531 static int 532 ngt_disconnect(hook_p hook) 533 { 534 const sc_p sc = hook->node->private; 535 536 crit_enter(); 537 lwkt_gettoken(&tty_token); 538 if (hook != sc->hook) 539 panic(__func__); 540 sc->hook = NULL; 541 m_freem(sc->m); 542 sc->m = NULL; 543 lwkt_reltoken(&tty_token); 544 crit_exit(); 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 */ 552 static int 553 ngt_shutdown(node_p node) 554 { 555 const sc_p sc = node->private; 556 557 if (!ngt_nodeop_ok) 558 return (EOPNOTSUPP); 559 lwkt_gettoken(&tty_token); 560 ng_unname(node); 561 ng_cutlinks(node); 562 node->private = NULL; 563 ng_unref(sc->node); 564 m_freem(sc->qhead); 565 m_freem(sc->m); 566 bzero(sc, sizeof(*sc)); 567 FREE(sc, M_NETGRAPH); 568 lwkt_reltoken(&tty_token); 569 return (0); 570 } 571 572 /* 573 * Receive incoming data from netgraph system. Put it on our 574 * output queue and start output if necessary. 575 */ 576 static int 577 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 578 { 579 const sc_p sc = hook->node->private; 580 int error = 0; 581 582 if (hook != sc->hook) 583 panic(__func__); 584 NG_FREE_META(meta); 585 crit_enter(); 586 lwkt_gettoken(&tty_token); 587 if (sc->qlen >= MAX_MBUFQ) 588 ERROUT(ENOBUFS); 589 m->m_nextpkt = NULL; 590 *sc->qtail = m; 591 sc->qtail = &m->m_nextpkt; 592 sc->qlen++; 593 QUEUECHECK(sc); 594 m = NULL; 595 if (sc->qlen == 1) 596 ngt_start(sc->tp); 597 done: 598 lwkt_reltoken(&tty_token); 599 crit_exit(); 600 if (m) 601 m_freem(m); 602 return (error); 603 } 604 605 /* 606 * Receive control message 607 */ 608 static int 609 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 610 struct ng_mesg **rptr) 611 { 612 const sc_p sc = (sc_p) node->private; 613 struct ng_mesg *resp = NULL; 614 int error = 0; 615 616 lwkt_gettoken(&tty_token); 617 switch (msg->header.typecookie) { 618 case NGM_TTY_COOKIE: 619 switch (msg->header.cmd) { 620 case NGM_TTY_SET_HOTCHAR: 621 { 622 int hotchar; 623 624 if (msg->header.arglen != sizeof(int)) 625 ERROUT(EINVAL); 626 hotchar = *((int *) msg->data); 627 if (hotchar != (u_char) hotchar && hotchar != -1) 628 ERROUT(EINVAL); 629 sc->hotchar = hotchar; /* race condition is OK */ 630 break; 631 } 632 case NGM_TTY_GET_HOTCHAR: 633 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 634 if (!resp) 635 ERROUT(ENOMEM); 636 /* Race condition here is OK */ 637 *((int *) resp->data) = sc->hotchar; 638 break; 639 default: 640 ERROUT(EINVAL); 641 } 642 break; 643 default: 644 ERROUT(EINVAL); 645 } 646 if (rptr) 647 *rptr = resp; 648 else if (resp) 649 FREE(resp, M_NETGRAPH); 650 651 done: 652 FREE(msg, M_NETGRAPH); 653 lwkt_reltoken(&tty_token); 654 return (error); 655 } 656 657 /****************************************************************** 658 INITIALIZATION 659 ******************************************************************/ 660 661 /* 662 * Handle loading and unloading for this node type 663 */ 664 static int 665 ngt_mod_event(module_t mod, int event, void *data) 666 { 667 /* struct ng_type *const type = data;*/ 668 int error = 0; 669 670 lwkt_gettoken(&tty_token); 671 switch (event) { 672 case MOD_LOAD: 673 /* Register line discipline */ 674 crit_enter(); 675 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 676 crit_exit(); 677 log(LOG_ERR, "%s: can't register line discipline", 678 __func__); 679 return (EIO); 680 } 681 crit_exit(); 682 break; 683 684 case MOD_UNLOAD: 685 686 /* Unregister line discipline */ 687 crit_enter(); 688 ldisc_deregister(ngt_ldisc); 689 crit_exit(); 690 break; 691 692 default: 693 error = EOPNOTSUPP; 694 break; 695 } 696 lwkt_reltoken(&tty_token); 697 return (error); 698 } 699