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 * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $ 42 */ 43 44 /* 45 * This file implements a terminal line discipline that is also a 46 * netgraph node. Installing this line discipline on a terminal device 47 * instantiates a new netgraph node of this type, which allows access 48 * to the device via the "hook" hook of the node. 49 * 50 * Once the line discipline is installed, you can find out the name 51 * of the corresponding netgraph node via a NGIOCGINFO ioctl(). 52 * 53 * Incoming characters are delievered to the hook one at a time, each 54 * in its own mbuf. You may optionally define a ``hotchar,'' which causes 55 * incoming characters to be buffered up until either the hotchar is 56 * seen or the mbuf is full (MHLEN bytes). Then all buffered characters 57 * are immediately delivered. 58 * 59 * NOTE: This node operates at spltty(). 60 */ 61 62 #include <sys/param.h> 63 #include <sys/systm.h> 64 #include <sys/kernel.h> 65 #include <sys/conf.h> 66 #include <sys/proc.h> 67 #include <sys/priv.h> 68 #include <sys/mbuf.h> 69 #include <sys/malloc.h> 70 #include <sys/fcntl.h> 71 #include <sys/tty.h> 72 #include <sys/ttycom.h> 73 #include <sys/syslog.h> 74 #include <sys/errno.h> 75 #include <sys/thread2.h> 76 77 #include <netgraph/ng_message.h> 78 #include <netgraph/netgraph.h> 79 #include "ng_tty.h" 80 81 /* Misc defs */ 82 #define MAX_MBUFQ 3 /* Max number of queued mbufs */ 83 #define NGT_HIWATER 400 /* High water mark on output */ 84 85 /* Per-node private info */ 86 struct ngt_sc { 87 struct tty *tp; /* Terminal device */ 88 node_p node; /* Netgraph node */ 89 hook_p hook; /* Netgraph hook */ 90 struct mbuf *m; /* Incoming data buffer */ 91 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */ 92 short qlen; /* Length of queue */ 93 short hotchar; /* Hotchar, or -1 if none */ 94 u_int flags; /* Flags */ 95 struct callout ctimeout; /* See man timeout(9) */ 96 }; 97 typedef struct ngt_sc *sc_p; 98 99 /* Flags */ 100 #define FLG_TIMEOUT 0x0001 /* A timeout is pending */ 101 #define FLG_DEBUG 0x0002 102 103 /* Debugging */ 104 #ifdef INVARIANTS 105 #define QUEUECHECK(sc) \ 106 do { \ 107 struct mbuf **mp; \ 108 int k; \ 109 \ 110 for (k = 0, mp = &sc->qhead; \ 111 k <= MAX_MBUFQ && *mp; \ 112 k++, mp = &(*mp)->m_nextpkt); \ 113 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \ 114 panic("%s: queue", __func__); \ 115 } while (0) 116 #else 117 #define QUEUECHECK(sc) do {} while (0) 118 #endif 119 120 /* Line discipline methods */ 121 static int ngt_open(cdev_t dev, struct tty *tp); 122 static int ngt_close(struct tty *tp, int flag); 123 static int ngt_read(struct tty *tp, struct uio *uio, int flag); 124 static int ngt_write(struct tty *tp, struct uio *uio, int flag); 125 static int ngt_tioctl(struct tty *tp, 126 u_long cmd, caddr_t data, int flag, struct ucred *cred); 127 static int ngt_input(int c, struct tty *tp); 128 static int ngt_start(struct tty *tp); 129 130 /* Netgraph methods */ 131 static ng_constructor_t ngt_constructor; 132 static ng_rcvmsg_t ngt_rcvmsg; 133 static ng_shutdown_t ngt_shutdown; 134 static ng_newhook_t ngt_newhook; 135 static ng_rcvdata_t ngt_rcvdata; 136 static ng_disconnect_t ngt_disconnect; 137 static int ngt_mod_event(module_t mod, int event, void *data); 138 139 /* Other stuff */ 140 static void ngt_timeout(void *arg); 141 142 #define ERROUT(x) do { error = (x); goto done; } while (0) 143 144 /* Line discipline descriptor */ 145 static 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 NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */ 155 }; 156 157 /* Netgraph node type descriptor */ 158 static struct ng_type typestruct = { 159 NG_VERSION, 160 NG_TTY_NODE_TYPE, 161 ngt_mod_event, 162 ngt_constructor, 163 ngt_rcvmsg, 164 ngt_shutdown, 165 ngt_newhook, 166 NULL, 167 NULL, 168 ngt_rcvdata, 169 ngt_rcvdata, 170 ngt_disconnect, 171 NULL 172 }; 173 NETGRAPH_INIT(tty, &typestruct); 174 175 static int ngt_unit; 176 static int ngt_nodeop_ok; /* OK to create/remove node */ 177 static int ngt_ldisc; 178 179 /****************************************************************** 180 LINE DISCIPLINE METHODS 181 ******************************************************************/ 182 183 /* 184 * Set our line discipline on the tty. 185 * Called from device open routine or ttioctl() at >= splsofttty() 186 */ 187 static int 188 ngt_open(cdev_t dev, struct tty *tp) 189 { 190 struct thread *td = curthread; /* XXX */ 191 char name[sizeof(NG_TTY_NODE_TYPE) + 8]; 192 sc_p sc; 193 int error; 194 195 /* Super-user only */ 196 if ((error = priv_check(td, PRIV_ROOT))) 197 return (error); 198 crit_enter(); 199 lwkt_gettoken(&tty_token); 200 201 /* Already installed? */ 202 if (tp->t_line == NETGRAPHDISC) { 203 sc = (sc_p) tp->t_sc; 204 if (sc != NULL && sc->tp == tp) 205 goto done; 206 } 207 208 /* Initialize private struct */ 209 sc = kmalloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO); 210 sc->tp = tp; 211 sc->hotchar = NG_TTY_DFL_HOTCHAR; 212 sc->qtail = &sc->qhead; 213 QUEUECHECK(sc); 214 callout_init_mp(&sc->ctimeout); 215 216 /* Setup netgraph node */ 217 ngt_nodeop_ok = 1; 218 error = ng_make_node_common(&typestruct, &sc->node); 219 ngt_nodeop_ok = 0; 220 if (error) { 221 kfree(sc, M_NETGRAPH); 222 goto done; 223 } 224 ksnprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++); 225 226 /* Set back pointers */ 227 sc->node->private = sc; 228 tp->t_sc = (caddr_t) sc; 229 230 /* Assign node its name */ 231 if ((error = ng_name_node(sc->node, name))) { 232 log(LOG_ERR, "%s: node name exists?\n", name); 233 ngt_nodeop_ok = 1; 234 ng_rmnode(sc->node); 235 ngt_nodeop_ok = 0; 236 goto done; 237 } 238 239 /* 240 * Pre-allocate cblocks to the an appropriate amount. 241 * I'm not sure what is appropriate. 242 */ 243 ttyflush(tp, FREAD | FWRITE); 244 clist_alloc_cblocks(&tp->t_canq, 0, 0); 245 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 246 clist_alloc_cblocks(&tp->t_outq, 247 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER); 248 249 done: 250 /* Done */ 251 lwkt_reltoken(&tty_token); 252 crit_exit(); 253 return (error); 254 } 255 256 /* 257 * Line specific close routine, called from device close routine 258 * and from ttioctl at >= splsofttty(). This causes the node to 259 * be destroyed as well. 260 */ 261 static int 262 ngt_close(struct tty *tp, int flag) 263 { 264 const sc_p sc = (sc_p) tp->t_sc; 265 266 crit_enter(); 267 lwkt_gettoken(&tty_token); 268 ttyflush(tp, FREAD | FWRITE); 269 clist_free_cblocks(&tp->t_outq); 270 tp->t_line = 0; 271 if (sc != NULL) { 272 if (sc->flags & FLG_TIMEOUT) { 273 callout_stop(&sc->ctimeout); 274 sc->flags &= ~FLG_TIMEOUT; 275 } 276 ngt_nodeop_ok = 1; 277 ng_rmnode(sc->node); 278 ngt_nodeop_ok = 0; 279 tp->t_sc = NULL; 280 } 281 lwkt_reltoken(&tty_token); 282 crit_exit(); 283 return (0); 284 } 285 286 /* 287 * Once the device has been turned into a node, we don't allow reading. 288 */ 289 static int 290 ngt_read(struct tty *tp, struct uio *uio, int flag) 291 { 292 return (EIO); 293 } 294 295 /* 296 * Once the device has been turned into a node, we don't allow writing. 297 */ 298 static int 299 ngt_write(struct tty *tp, struct uio *uio, int flag) 300 { 301 return (EIO); 302 } 303 304 /* 305 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 306 */ 307 static int 308 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred) 309 { 310 const sc_p sc = (sc_p) tp->t_sc; 311 int error = 0; 312 313 crit_enter(); 314 lwkt_gettoken(&tty_token); 315 switch (cmd) { 316 case NGIOCGINFO: 317 { 318 struct nodeinfo *const ni = (struct nodeinfo *) data; 319 const node_p node = sc->node; 320 321 bzero(ni, sizeof(*ni)); 322 if (node->name) 323 strncpy(ni->name, node->name, sizeof(ni->name) - 1); 324 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1); 325 ni->id = (u_int32_t)(uintptr_t)node; 326 ni->hooks = node->numhooks; 327 break; 328 } 329 default: 330 ERROUT(ENOIOCTL); 331 } 332 done: 333 lwkt_reltoken(&tty_token); 334 crit_exit(); 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 */ 343 static int 344 ngt_input(int c, struct tty *tp) 345 { 346 const sc_p sc = (sc_p) tp->t_sc; 347 const node_p node = sc ? sc->node : NULL; 348 struct mbuf *m; 349 int error = 0; 350 351 lwkt_gettoken(&tty_token); 352 if (!sc || tp != sc->tp) { 353 lwkt_reltoken(&tty_token); 354 return (0); 355 } 356 crit_enter(); 357 if (!sc->hook) 358 ERROUT(0); 359 360 /* Check for error conditions */ 361 if ((tp->t_state & TS_CONNECTED) == 0) { 362 if (sc->flags & FLG_DEBUG) 363 log(LOG_DEBUG, "%s: no carrier\n", node->name); 364 ERROUT(0); 365 } 366 if (c & TTY_ERRORMASK) { 367 /* framing error or overrun on this char */ 368 if (sc->flags & FLG_DEBUG) 369 log(LOG_DEBUG, "%s: line error %x\n", 370 node->name, c & TTY_ERRORMASK); 371 ERROUT(0); 372 } 373 c &= TTY_CHARMASK; 374 375 /* Get a new header mbuf if we need one */ 376 if (!(m = sc->m)) { 377 MGETHDR(m, MB_DONTWAIT, MT_DATA); 378 if (!m) { 379 if (sc->flags & FLG_DEBUG) 380 log(LOG_ERR, 381 "%s: can't get mbuf\n", node->name); 382 ERROUT(ENOBUFS); 383 } 384 m->m_len = m->m_pkthdr.len = 0; 385 m->m_pkthdr.rcvif = NULL; 386 sc->m = m; 387 } 388 389 /* Add char to mbuf */ 390 *mtod(m, u_char *) = c; 391 m->m_data++; 392 m->m_len++; 393 m->m_pkthdr.len++; 394 395 /* Ship off mbuf if it's time */ 396 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 397 m->m_data = m->m_pktdat; 398 error = ng_queue_data(sc->hook, m, NULL); 399 sc->m = NULL; 400 } 401 done: 402 crit_exit(); 403 lwkt_reltoken(&tty_token); 404 return (error); 405 } 406 407 /* 408 * This is called when the device driver is ready for more output. 409 * Called from tty system at splsofttty() or spltty(). 410 * Also call from ngt_rcv_data() when a new mbuf is available for output. 411 */ 412 static int 413 ngt_start(struct tty *tp) 414 { 415 const sc_p sc = (sc_p) tp->t_sc; 416 417 crit_enter(); 418 lwkt_gettoken(&tty_token); 419 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 420 struct mbuf *m = sc->qhead; 421 422 /* Remove first mbuf from queue */ 423 if (!m) 424 break; 425 if ((sc->qhead = m->m_nextpkt) == NULL) 426 sc->qtail = &sc->qhead; 427 sc->qlen--; 428 QUEUECHECK(sc); 429 430 /* Send as much of it as possible */ 431 while (m) { 432 int sent; 433 434 sent = m->m_len 435 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq); 436 m->m_data += sent; 437 m->m_len -= sent; 438 if (m->m_len > 0) 439 break; /* device can't take no more */ 440 m = m_free(m); 441 } 442 443 /* Put remainder of mbuf chain (if any) back on queue */ 444 if (m) { 445 m->m_nextpkt = sc->qhead; 446 sc->qhead = m; 447 if (sc->qtail == &sc->qhead) 448 sc->qtail = &m->m_nextpkt; 449 sc->qlen++; 450 QUEUECHECK(sc); 451 break; 452 } 453 } 454 455 /* Call output process whether or not there is any output. We are 456 * being called in lieu of ttstart and must do what it would. */ 457 if (tp->t_oproc != NULL) 458 (*tp->t_oproc) (tp); 459 460 /* This timeout is needed for operation on a pseudo-tty, because the 461 * pty code doesn't call pppstart after it has drained the t_outq. */ 462 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 463 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc); 464 sc->flags |= FLG_TIMEOUT; 465 } 466 lwkt_reltoken(&tty_token); 467 crit_exit(); 468 return (0); 469 } 470 471 /* 472 * We still have data to output to the device, so try sending more. 473 */ 474 static void 475 ngt_timeout(void *arg) 476 { 477 const sc_p sc = (sc_p) arg; 478 479 crit_enter(); 480 lwkt_gettoken(&tty_token); 481 sc->flags &= ~FLG_TIMEOUT; 482 ngt_start(sc->tp); 483 lwkt_reltoken(&tty_token); 484 crit_exit(); 485 } 486 487 /****************************************************************** 488 NETGRAPH NODE METHODS 489 ******************************************************************/ 490 491 /* 492 * Initialize a new node of this type. 493 * 494 * We only allow nodes to be created as a result of setting 495 * the line discipline on a tty, so always return an error if not. 496 */ 497 static int 498 ngt_constructor(node_p *nodep) 499 { 500 if (!ngt_nodeop_ok) 501 return (EOPNOTSUPP); 502 return (ng_make_node_common(&typestruct, nodep)); 503 } 504 505 /* 506 * Add a new hook. There can only be one. 507 */ 508 static int 509 ngt_newhook(node_p node, hook_p hook, const char *name) 510 { 511 const sc_p sc = node->private; 512 int error = 0; 513 514 if (strcmp(name, NG_TTY_HOOK)) 515 return (EINVAL); 516 crit_enter(); 517 lwkt_gettoken(&tty_token); 518 if (sc->hook) 519 ERROUT(EISCONN); 520 sc->hook = hook; 521 done: 522 lwkt_reltoken(&tty_token); 523 crit_exit(); 524 return (error); 525 } 526 527 /* 528 * Disconnect the hook 529 */ 530 static int 531 ngt_disconnect(hook_p hook) 532 { 533 const sc_p sc = hook->node->private; 534 535 crit_enter(); 536 lwkt_gettoken(&tty_token); 537 if (hook != sc->hook) 538 panic(__func__); 539 sc->hook = NULL; 540 m_freem(sc->m); 541 sc->m = NULL; 542 lwkt_reltoken(&tty_token); 543 crit_exit(); 544 return (0); 545 } 546 547 /* 548 * Remove this node. The does the netgraph portion of the shutdown. 549 * This should only be called indirectly from ngt_close(). 550 */ 551 static int 552 ngt_shutdown(node_p node) 553 { 554 const sc_p sc = node->private; 555 556 if (!ngt_nodeop_ok) 557 return (EOPNOTSUPP); 558 lwkt_gettoken(&tty_token); 559 ng_unname(node); 560 ng_cutlinks(node); 561 node->private = NULL; 562 ng_unref(sc->node); 563 m_freem(sc->qhead); 564 m_freem(sc->m); 565 bzero(sc, sizeof(*sc)); 566 kfree(sc, M_NETGRAPH); 567 lwkt_reltoken(&tty_token); 568 return (0); 569 } 570 571 /* 572 * Receive incoming data from netgraph system. Put it on our 573 * output queue and start output if necessary. 574 */ 575 static int 576 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 577 { 578 const sc_p sc = hook->node->private; 579 int error = 0; 580 581 if (hook != sc->hook) 582 panic(__func__); 583 NG_FREE_META(meta); 584 crit_enter(); 585 lwkt_gettoken(&tty_token); 586 if (sc->qlen >= MAX_MBUFQ) 587 ERROUT(ENOBUFS); 588 m->m_nextpkt = NULL; 589 *sc->qtail = m; 590 sc->qtail = &m->m_nextpkt; 591 sc->qlen++; 592 QUEUECHECK(sc); 593 m = NULL; 594 if (sc->qlen == 1) 595 ngt_start(sc->tp); 596 done: 597 lwkt_reltoken(&tty_token); 598 crit_exit(); 599 if (m) 600 m_freem(m); 601 return (error); 602 } 603 604 /* 605 * Receive control message 606 */ 607 static int 608 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 609 struct ng_mesg **rptr) 610 { 611 const sc_p sc = (sc_p) node->private; 612 struct ng_mesg *resp = NULL; 613 int error = 0; 614 615 lwkt_gettoken(&tty_token); 616 switch (msg->header.typecookie) { 617 case NGM_TTY_COOKIE: 618 switch (msg->header.cmd) { 619 case NGM_TTY_SET_HOTCHAR: 620 { 621 int hotchar; 622 623 if (msg->header.arglen != sizeof(int)) 624 ERROUT(EINVAL); 625 hotchar = *((int *) msg->data); 626 if (hotchar != (u_char) hotchar && hotchar != -1) 627 ERROUT(EINVAL); 628 sc->hotchar = hotchar; /* race condition is OK */ 629 break; 630 } 631 case NGM_TTY_GET_HOTCHAR: 632 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 633 if (!resp) 634 ERROUT(ENOMEM); 635 /* Race condition here is OK */ 636 *((int *) resp->data) = sc->hotchar; 637 break; 638 default: 639 ERROUT(EINVAL); 640 } 641 break; 642 default: 643 ERROUT(EINVAL); 644 } 645 if (rptr) 646 *rptr = resp; 647 else if (resp) 648 kfree(resp, M_NETGRAPH); 649 650 done: 651 kfree(msg, M_NETGRAPH); 652 lwkt_reltoken(&tty_token); 653 return (error); 654 } 655 656 /****************************************************************** 657 INITIALIZATION 658 ******************************************************************/ 659 660 /* 661 * Handle loading and unloading for this node type 662 */ 663 static int 664 ngt_mod_event(module_t mod, int event, void *data) 665 { 666 /* struct ng_type *const type = data;*/ 667 int error = 0; 668 669 lwkt_gettoken(&tty_token); 670 switch (event) { 671 case MOD_LOAD: 672 /* Register line discipline */ 673 crit_enter(); 674 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 675 crit_exit(); 676 log(LOG_ERR, "%s: can't register line discipline", 677 __func__); 678 lwkt_reltoken(&tty_token); 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