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: src/sys/netgraph/ng_tty.c,v 1.7.2.3 2002/02/13 00:43:12 dillon Exp $ 40 * $DragonFly: src/sys/netgraph/tty/ng_tty.c,v 1.9 2005/02/17 14:00:00 joerg 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/mbuf.h> 68 #include <sys/malloc.h> 69 #include <sys/fcntl.h> 70 #include <sys/tty.h> 71 #include <sys/ttycom.h> 72 #include <sys/syslog.h> 73 #include <sys/errno.h> 74 #include <sys/ioccom.h> 75 76 #include <netgraph/ng_message.h> 77 #include <netgraph/netgraph.h> 78 #include "ng_tty.h" 79 80 #ifdef __i386__ /* fiddle with the spl locking */ 81 #include <machine/ipl.h> 82 #include <i386/isa/intr_machdep.h> 83 #endif 84 85 /* Misc defs */ 86 #define MAX_MBUFQ 3 /* Max number of queued mbufs */ 87 #define NGT_HIWATER 400 /* High water mark on output */ 88 89 /* Per-node private info */ 90 struct ngt_sc { 91 struct tty *tp; /* Terminal device */ 92 node_p node; /* Netgraph node */ 93 hook_p hook; /* Netgraph hook */ 94 struct mbuf *m; /* Incoming data buffer */ 95 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */ 96 short qlen; /* Length of queue */ 97 short hotchar; /* Hotchar, or -1 if none */ 98 u_int flags; /* Flags */ 99 struct callout ctimeout; /* See man timeout(9) */ 100 }; 101 typedef struct ngt_sc *sc_p; 102 103 /* Flags */ 104 #define FLG_TIMEOUT 0x0001 /* A timeout is pending */ 105 #define FLG_DEBUG 0x0002 106 107 /* Debugging */ 108 #ifdef INVARIANTS 109 #define QUEUECHECK(sc) \ 110 do { \ 111 struct mbuf **mp; \ 112 int k; \ 113 \ 114 for (k = 0, mp = &sc->qhead; \ 115 k <= MAX_MBUFQ && *mp; \ 116 k++, mp = &(*mp)->m_nextpkt); \ 117 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \ 118 panic("%s: queue", __func__); \ 119 } while (0) 120 #else 121 #define QUEUECHECK(sc) do {} while (0) 122 #endif 123 124 /* Line discipline methods */ 125 static int ngt_open(dev_t dev, struct tty *tp); 126 static int ngt_close(struct tty *tp, int flag); 127 static int ngt_read(struct tty *tp, struct uio *uio, int flag); 128 static int ngt_write(struct tty *tp, struct uio *uio, int flag); 129 static int ngt_tioctl(struct tty *tp, 130 u_long cmd, caddr_t data, int flag, d_thread_t *td); 131 static int ngt_input(int c, struct tty *tp); 132 static int ngt_start(struct tty *tp); 133 134 /* Netgraph methods */ 135 static ng_constructor_t ngt_constructor; 136 static ng_rcvmsg_t ngt_rcvmsg; 137 static ng_shutdown_t ngt_shutdown; 138 static ng_newhook_t ngt_newhook; 139 static ng_rcvdata_t ngt_rcvdata; 140 static ng_disconnect_t ngt_disconnect; 141 static int ngt_mod_event(module_t mod, int event, void *data); 142 143 /* Other stuff */ 144 static void ngt_timeout(void *arg); 145 146 #define ERROUT(x) do { error = (x); goto done; } while (0) 147 148 /* Line discipline descriptor */ 149 static struct linesw ngt_disc = { 150 ngt_open, 151 ngt_close, 152 ngt_read, 153 ngt_write, 154 ngt_tioctl, 155 ngt_input, 156 ngt_start, 157 ttymodem, 158 NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */ 159 }; 160 161 /* Netgraph node type descriptor */ 162 static struct ng_type typestruct = { 163 NG_VERSION, 164 NG_TTY_NODE_TYPE, 165 ngt_mod_event, 166 ngt_constructor, 167 ngt_rcvmsg, 168 ngt_shutdown, 169 ngt_newhook, 170 NULL, 171 NULL, 172 ngt_rcvdata, 173 ngt_rcvdata, 174 ngt_disconnect, 175 NULL 176 }; 177 NETGRAPH_INIT(tty, &typestruct); 178 179 static int ngt_unit; 180 static int ngt_nodeop_ok; /* OK to create/remove node */ 181 static int ngt_ldisc; 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 */ 191 static int 192 ngt_open(dev_t dev, struct tty *tp) 193 { 194 struct thread *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 /* Already installed? */ 206 if (tp->t_line == NETGRAPHDISC) { 207 sc = (sc_p) tp->t_sc; 208 if (sc != NULL && sc->tp == tp) 209 goto done; 210 } 211 212 /* Initialize private struct */ 213 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK); 214 if (sc == NULL) { 215 error = ENOMEM; 216 goto done; 217 } 218 bzero(sc, sizeof(*sc)); 219 sc->tp = tp; 220 sc->hotchar = NG_TTY_DFL_HOTCHAR; 221 sc->qtail = &sc->qhead; 222 QUEUECHECK(sc); 223 callout_init(&sc->ctimeout); 224 225 /* Setup netgraph node */ 226 ngt_nodeop_ok = 1; 227 error = ng_make_node_common(&typestruct, &sc->node); 228 ngt_nodeop_ok = 0; 229 if (error) { 230 FREE(sc, M_NETGRAPH); 231 goto done; 232 } 233 snprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++); 234 235 /* Set back pointers */ 236 sc->node->private = sc; 237 tp->t_sc = (caddr_t) sc; 238 239 /* Assign node its name */ 240 if ((error = ng_name_node(sc->node, name))) { 241 log(LOG_ERR, "%s: node name exists?\n", name); 242 ngt_nodeop_ok = 1; 243 ng_rmnode(sc->node); 244 ngt_nodeop_ok = 0; 245 goto done; 246 } 247 248 /* 249 * Pre-allocate cblocks to the an appropriate amount. 250 * I'm not sure what is appropriate. 251 */ 252 ttyflush(tp, FREAD | FWRITE); 253 clist_alloc_cblocks(&tp->t_canq, 0, 0); 254 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 255 clist_alloc_cblocks(&tp->t_outq, 256 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER); 257 258 done: 259 /* Done */ 260 splx(s); 261 return (error); 262 } 263 264 /* 265 * Line specific close routine, called from device close routine 266 * and from ttioctl at >= splsofttty(). This causes the node to 267 * be destroyed as well. 268 */ 269 static int 270 ngt_close(struct tty *tp, int flag) 271 { 272 const sc_p sc = (sc_p) tp->t_sc; 273 int s; 274 275 s = spltty(); 276 ttyflush(tp, FREAD | FWRITE); 277 clist_free_cblocks(&tp->t_outq); 278 tp->t_line = 0; 279 if (sc != NULL) { 280 if (sc->flags & FLG_TIMEOUT) { 281 callout_stop(&sc->ctimeout); 282 sc->flags &= ~FLG_TIMEOUT; 283 } 284 ngt_nodeop_ok = 1; 285 ng_rmnode(sc->node); 286 ngt_nodeop_ok = 0; 287 tp->t_sc = NULL; 288 } 289 splx(s); 290 return (0); 291 } 292 293 /* 294 * Once the device has been turned into a node, we don't allow reading. 295 */ 296 static int 297 ngt_read(struct tty *tp, struct uio *uio, int flag) 298 { 299 return (EIO); 300 } 301 302 /* 303 * Once the device has been turned into a node, we don't allow writing. 304 */ 305 static int 306 ngt_write(struct tty *tp, struct uio *uio, int flag) 307 { 308 return (EIO); 309 } 310 311 /* 312 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 313 */ 314 static int 315 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, d_thread_t *td) 316 { 317 const sc_p sc = (sc_p) tp->t_sc; 318 int s, error = 0; 319 320 s = spltty(); 321 switch (cmd) { 322 case NGIOCGINFO: 323 { 324 struct nodeinfo *const ni = (struct nodeinfo *) data; 325 const node_p node = sc->node; 326 327 bzero(ni, sizeof(*ni)); 328 if (node->name) 329 strncpy(ni->name, node->name, sizeof(ni->name) - 1); 330 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1); 331 ni->id = (u_int32_t) node; 332 ni->hooks = node->numhooks; 333 break; 334 } 335 default: 336 ERROUT(ENOIOCTL); 337 } 338 done: 339 splx(s); 340 return (error); 341 } 342 343 /* 344 * Receive data coming from the device. We get one character at 345 * a time, which is kindof silly. 346 * Only guaranteed to be at splsofttty() or spltty(). 347 */ 348 static int 349 ngt_input(int c, struct tty *tp) 350 { 351 const sc_p sc = (sc_p) tp->t_sc; 352 const node_p node = sc->node; 353 struct mbuf *m; 354 int s, error = 0; 355 356 if (!sc || tp != sc->tp) 357 return (0); 358 s = spltty(); 359 if (!sc->hook) 360 ERROUT(0); 361 362 /* Check for error conditions */ 363 if ((tp->t_state & TS_CONNECTED) == 0) { 364 if (sc->flags & FLG_DEBUG) 365 log(LOG_DEBUG, "%s: no carrier\n", node->name); 366 ERROUT(0); 367 } 368 if (c & TTY_ERRORMASK) { 369 /* framing error or overrun on this char */ 370 if (sc->flags & FLG_DEBUG) 371 log(LOG_DEBUG, "%s: line error %x\n", 372 node->name, c & TTY_ERRORMASK); 373 ERROUT(0); 374 } 375 c &= TTY_CHARMASK; 376 377 /* Get a new header mbuf if we need one */ 378 if (!(m = sc->m)) { 379 MGETHDR(m, MB_DONTWAIT, MT_DATA); 380 if (!m) { 381 if (sc->flags & FLG_DEBUG) 382 log(LOG_ERR, 383 "%s: can't get mbuf\n", node->name); 384 ERROUT(ENOBUFS); 385 } 386 m->m_len = m->m_pkthdr.len = 0; 387 m->m_pkthdr.rcvif = NULL; 388 sc->m = m; 389 } 390 391 /* Add char to mbuf */ 392 *mtod(m, u_char *) = c; 393 m->m_data++; 394 m->m_len++; 395 m->m_pkthdr.len++; 396 397 /* Ship off mbuf if it's time */ 398 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 399 m->m_data = m->m_pktdat; 400 error = ng_queue_data(sc->hook, m, NULL); 401 sc->m = NULL; 402 } 403 done: 404 splx(s); 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 int s; 418 419 s = spltty(); 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 splx(s); 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 int s; 479 480 s = spltty(); 481 sc->flags &= ~FLG_TIMEOUT; 482 ngt_start(sc->tp); 483 splx(s); 484 } 485 486 /****************************************************************** 487 NETGRAPH NODE METHODS 488 ******************************************************************/ 489 490 /* 491 * Initialize a new node of this type. 492 * 493 * We only allow nodes to be created as a result of setting 494 * the line discipline on a tty, so always return an error if not. 495 */ 496 static int 497 ngt_constructor(node_p *nodep) 498 { 499 if (!ngt_nodeop_ok) 500 return (EOPNOTSUPP); 501 return (ng_make_node_common(&typestruct, nodep)); 502 } 503 504 /* 505 * Add a new hook. There can only be one. 506 */ 507 static int 508 ngt_newhook(node_p node, hook_p hook, const char *name) 509 { 510 const sc_p sc = node->private; 511 int s, error = 0; 512 513 if (strcmp(name, NG_TTY_HOOK)) 514 return (EINVAL); 515 s = spltty(); 516 if (sc->hook) 517 ERROUT(EISCONN); 518 sc->hook = hook; 519 done: 520 splx(s); 521 return (error); 522 } 523 524 /* 525 * Disconnect the hook 526 */ 527 static int 528 ngt_disconnect(hook_p hook) 529 { 530 const sc_p sc = hook->node->private; 531 int s; 532 533 s = spltty(); 534 if (hook != sc->hook) 535 panic(__func__); 536 sc->hook = NULL; 537 m_freem(sc->m); 538 sc->m = NULL; 539 splx(s); 540 return (0); 541 } 542 543 /* 544 * Remove this node. The does the netgraph portion of the shutdown. 545 * This should only be called indirectly from ngt_close(). 546 */ 547 static int 548 ngt_shutdown(node_p node) 549 { 550 const sc_p sc = node->private; 551 552 if (!ngt_nodeop_ok) 553 return (EOPNOTSUPP); 554 ng_unname(node); 555 ng_cutlinks(node); 556 node->private = NULL; 557 ng_unref(sc->node); 558 m_freem(sc->qhead); 559 m_freem(sc->m); 560 bzero(sc, sizeof(*sc)); 561 FREE(sc, M_NETGRAPH); 562 return (0); 563 } 564 565 /* 566 * Receive incoming data from netgraph system. Put it on our 567 * output queue and start output if necessary. 568 */ 569 static int 570 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 571 { 572 const sc_p sc = hook->node->private; 573 int s, error = 0; 574 575 if (hook != sc->hook) 576 panic(__func__); 577 NG_FREE_META(meta); 578 s = spltty(); 579 if (sc->qlen >= MAX_MBUFQ) 580 ERROUT(ENOBUFS); 581 m->m_nextpkt = NULL; 582 *sc->qtail = m; 583 sc->qtail = &m->m_nextpkt; 584 sc->qlen++; 585 QUEUECHECK(sc); 586 m = NULL; 587 if (sc->qlen == 1) 588 ngt_start(sc->tp); 589 done: 590 splx(s); 591 if (m) 592 m_freem(m); 593 return (error); 594 } 595 596 /* 597 * Receive control message 598 */ 599 static int 600 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 601 struct ng_mesg **rptr) 602 { 603 const sc_p sc = (sc_p) node->private; 604 struct ng_mesg *resp = NULL; 605 int error = 0; 606 607 switch (msg->header.typecookie) { 608 case NGM_TTY_COOKIE: 609 switch (msg->header.cmd) { 610 case NGM_TTY_SET_HOTCHAR: 611 { 612 int hotchar; 613 614 if (msg->header.arglen != sizeof(int)) 615 ERROUT(EINVAL); 616 hotchar = *((int *) msg->data); 617 if (hotchar != (u_char) hotchar && hotchar != -1) 618 ERROUT(EINVAL); 619 sc->hotchar = hotchar; /* race condition is OK */ 620 break; 621 } 622 case NGM_TTY_GET_HOTCHAR: 623 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 624 if (!resp) 625 ERROUT(ENOMEM); 626 /* Race condition here is OK */ 627 *((int *) resp->data) = sc->hotchar; 628 break; 629 default: 630 ERROUT(EINVAL); 631 } 632 break; 633 default: 634 ERROUT(EINVAL); 635 } 636 if (rptr) 637 *rptr = resp; 638 else if (resp) 639 FREE(resp, M_NETGRAPH); 640 641 done: 642 FREE(msg, M_NETGRAPH); 643 return (error); 644 } 645 646 /****************************************************************** 647 INITIALIZATION 648 ******************************************************************/ 649 650 /* 651 * Handle loading and unloading for this node type 652 */ 653 static int 654 ngt_mod_event(module_t mod, int event, void *data) 655 { 656 /* struct ng_type *const type = data;*/ 657 int s, error = 0; 658 659 switch (event) { 660 case MOD_LOAD: 661 #ifdef __i386__ 662 /* Insure the soft net "engine" can't run during spltty code */ 663 s = splhigh(); 664 tty_imask |= softnet_imask; /* spltty() block spl[soft]net() */ 665 net_imask |= softtty_imask; /* splimp() block splsofttty() */ 666 net_imask |= tty_imask; /* splimp() block spltty() */ 667 update_intr_masks(); 668 splx(s); 669 670 if (bootverbose) 671 log(LOG_DEBUG, "new masks: bio %x, tty %x, net %x\n", 672 bio_imask, tty_imask, net_imask); 673 #endif 674 675 /* Register line discipline */ 676 s = spltty(); 677 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 678 splx(s); 679 log(LOG_ERR, "%s: can't register line discipline", 680 __func__); 681 return (EIO); 682 } 683 splx(s); 684 break; 685 686 case MOD_UNLOAD: 687 688 /* Unregister line discipline */ 689 s = spltty(); 690 ldisc_deregister(ngt_ldisc); 691 splx(s); 692 break; 693 694 default: 695 error = EOPNOTSUPP; 696 break; 697 } 698 return (error); 699 } 700 701