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 1.19 2008/01/06 16:55:52 swildner 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(); 199 200 /* Already installed? */ 201 if (tp->t_line == NETGRAPHDISC) { 202 sc = (sc_p) tp->t_sc; 203 if (sc != NULL && sc->tp == tp) 204 goto done; 205 } 206 207 /* Initialize private struct */ 208 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO); 209 sc->tp = tp; 210 sc->hotchar = NG_TTY_DFL_HOTCHAR; 211 sc->qtail = &sc->qhead; 212 QUEUECHECK(sc); 213 callout_init(&sc->ctimeout); 214 215 /* Setup netgraph node */ 216 ngt_nodeop_ok = 1; 217 error = ng_make_node_common(&typestruct, &sc->node); 218 ngt_nodeop_ok = 0; 219 if (error) { 220 FREE(sc, M_NETGRAPH); 221 goto done; 222 } 223 ksnprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++); 224 225 /* Set back pointers */ 226 sc->node->private = sc; 227 tp->t_sc = (caddr_t) sc; 228 229 /* Assign node its name */ 230 if ((error = ng_name_node(sc->node, name))) { 231 log(LOG_ERR, "%s: node name exists?\n", name); 232 ngt_nodeop_ok = 1; 233 ng_rmnode(sc->node); 234 ngt_nodeop_ok = 0; 235 goto done; 236 } 237 238 /* 239 * Pre-allocate cblocks to the an appropriate amount. 240 * I'm not sure what is appropriate. 241 */ 242 ttyflush(tp, FREAD | FWRITE); 243 clist_alloc_cblocks(&tp->t_canq, 0, 0); 244 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 245 clist_alloc_cblocks(&tp->t_outq, 246 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER); 247 248 done: 249 /* Done */ 250 crit_exit(); 251 return (error); 252 } 253 254 /* 255 * Line specific close routine, called from device close routine 256 * and from ttioctl at >= splsofttty(). This causes the node to 257 * be destroyed as well. 258 */ 259 static int 260 ngt_close(struct tty *tp, int flag) 261 { 262 const sc_p sc = (sc_p) tp->t_sc; 263 264 crit_enter(); 265 ttyflush(tp, FREAD | FWRITE); 266 clist_free_cblocks(&tp->t_outq); 267 tp->t_line = 0; 268 if (sc != NULL) { 269 if (sc->flags & FLG_TIMEOUT) { 270 callout_stop(&sc->ctimeout); 271 sc->flags &= ~FLG_TIMEOUT; 272 } 273 ngt_nodeop_ok = 1; 274 ng_rmnode(sc->node); 275 ngt_nodeop_ok = 0; 276 tp->t_sc = NULL; 277 } 278 crit_exit(); 279 return (0); 280 } 281 282 /* 283 * Once the device has been turned into a node, we don't allow reading. 284 */ 285 static int 286 ngt_read(struct tty *tp, struct uio *uio, int flag) 287 { 288 return (EIO); 289 } 290 291 /* 292 * Once the device has been turned into a node, we don't allow writing. 293 */ 294 static int 295 ngt_write(struct tty *tp, struct uio *uio, int flag) 296 { 297 return (EIO); 298 } 299 300 /* 301 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 302 */ 303 static int 304 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred) 305 { 306 const sc_p sc = (sc_p) tp->t_sc; 307 int error = 0; 308 309 crit_enter(); 310 switch (cmd) { 311 case NGIOCGINFO: 312 { 313 struct nodeinfo *const ni = (struct nodeinfo *) data; 314 const node_p node = sc->node; 315 316 bzero(ni, sizeof(*ni)); 317 if (node->name) 318 strncpy(ni->name, node->name, sizeof(ni->name) - 1); 319 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1); 320 ni->id = (u_int32_t)(uintptr_t)node; 321 ni->hooks = node->numhooks; 322 break; 323 } 324 default: 325 ERROUT(ENOIOCTL); 326 } 327 done: 328 crit_exit(); 329 return (error); 330 } 331 332 /* 333 * Receive data coming from the device. We get one character at 334 * a time, which is kindof silly. 335 * Only guaranteed to be at splsofttty() or spltty(). 336 */ 337 static int 338 ngt_input(int c, struct tty *tp) 339 { 340 const sc_p sc = (sc_p) tp->t_sc; 341 const node_p node = sc->node; 342 struct mbuf *m; 343 int error = 0; 344 345 if (!sc || tp != sc->tp) 346 return (0); 347 crit_enter(); 348 if (!sc->hook) 349 ERROUT(0); 350 351 /* Check for error conditions */ 352 if ((tp->t_state & TS_CONNECTED) == 0) { 353 if (sc->flags & FLG_DEBUG) 354 log(LOG_DEBUG, "%s: no carrier\n", node->name); 355 ERROUT(0); 356 } 357 if (c & TTY_ERRORMASK) { 358 /* framing error or overrun on this char */ 359 if (sc->flags & FLG_DEBUG) 360 log(LOG_DEBUG, "%s: line error %x\n", 361 node->name, c & TTY_ERRORMASK); 362 ERROUT(0); 363 } 364 c &= TTY_CHARMASK; 365 366 /* Get a new header mbuf if we need one */ 367 if (!(m = sc->m)) { 368 MGETHDR(m, MB_DONTWAIT, MT_DATA); 369 if (!m) { 370 if (sc->flags & FLG_DEBUG) 371 log(LOG_ERR, 372 "%s: can't get mbuf\n", node->name); 373 ERROUT(ENOBUFS); 374 } 375 m->m_len = m->m_pkthdr.len = 0; 376 m->m_pkthdr.rcvif = NULL; 377 sc->m = m; 378 } 379 380 /* Add char to mbuf */ 381 *mtod(m, u_char *) = c; 382 m->m_data++; 383 m->m_len++; 384 m->m_pkthdr.len++; 385 386 /* Ship off mbuf if it's time */ 387 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 388 m->m_data = m->m_pktdat; 389 error = ng_queue_data(sc->hook, m, NULL); 390 sc->m = NULL; 391 } 392 done: 393 crit_exit(); 394 return (error); 395 } 396 397 /* 398 * This is called when the device driver is ready for more output. 399 * Called from tty system at splsofttty() or spltty(). 400 * Also call from ngt_rcv_data() when a new mbuf is available for output. 401 */ 402 static int 403 ngt_start(struct tty *tp) 404 { 405 const sc_p sc = (sc_p) tp->t_sc; 406 407 crit_enter(); 408 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 409 struct mbuf *m = sc->qhead; 410 411 /* Remove first mbuf from queue */ 412 if (!m) 413 break; 414 if ((sc->qhead = m->m_nextpkt) == NULL) 415 sc->qtail = &sc->qhead; 416 sc->qlen--; 417 QUEUECHECK(sc); 418 419 /* Send as much of it as possible */ 420 while (m) { 421 int sent; 422 423 sent = m->m_len 424 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq); 425 m->m_data += sent; 426 m->m_len -= sent; 427 if (m->m_len > 0) 428 break; /* device can't take no more */ 429 m = m_free(m); 430 } 431 432 /* Put remainder of mbuf chain (if any) back on queue */ 433 if (m) { 434 m->m_nextpkt = sc->qhead; 435 sc->qhead = m; 436 if (sc->qtail == &sc->qhead) 437 sc->qtail = &m->m_nextpkt; 438 sc->qlen++; 439 QUEUECHECK(sc); 440 break; 441 } 442 } 443 444 /* Call output process whether or not there is any output. We are 445 * being called in lieu of ttstart and must do what it would. */ 446 if (tp->t_oproc != NULL) 447 (*tp->t_oproc) (tp); 448 449 /* This timeout is needed for operation on a pseudo-tty, because the 450 * pty code doesn't call pppstart after it has drained the t_outq. */ 451 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 452 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc); 453 sc->flags |= FLG_TIMEOUT; 454 } 455 crit_exit(); 456 return (0); 457 } 458 459 /* 460 * We still have data to output to the device, so try sending more. 461 */ 462 static void 463 ngt_timeout(void *arg) 464 { 465 const sc_p sc = (sc_p) arg; 466 467 crit_enter(); 468 sc->flags &= ~FLG_TIMEOUT; 469 ngt_start(sc->tp); 470 crit_exit(); 471 } 472 473 /****************************************************************** 474 NETGRAPH NODE METHODS 475 ******************************************************************/ 476 477 /* 478 * Initialize a new node of this type. 479 * 480 * We only allow nodes to be created as a result of setting 481 * the line discipline on a tty, so always return an error if not. 482 */ 483 static int 484 ngt_constructor(node_p *nodep) 485 { 486 if (!ngt_nodeop_ok) 487 return (EOPNOTSUPP); 488 return (ng_make_node_common(&typestruct, nodep)); 489 } 490 491 /* 492 * Add a new hook. There can only be one. 493 */ 494 static int 495 ngt_newhook(node_p node, hook_p hook, const char *name) 496 { 497 const sc_p sc = node->private; 498 int error = 0; 499 500 if (strcmp(name, NG_TTY_HOOK)) 501 return (EINVAL); 502 crit_enter(); 503 if (sc->hook) 504 ERROUT(EISCONN); 505 sc->hook = hook; 506 done: 507 crit_exit(); 508 return (error); 509 } 510 511 /* 512 * Disconnect the hook 513 */ 514 static int 515 ngt_disconnect(hook_p hook) 516 { 517 const sc_p sc = hook->node->private; 518 519 crit_enter(); 520 if (hook != sc->hook) 521 panic(__func__); 522 sc->hook = NULL; 523 m_freem(sc->m); 524 sc->m = NULL; 525 crit_exit(); 526 return (0); 527 } 528 529 /* 530 * Remove this node. The does the netgraph portion of the shutdown. 531 * This should only be called indirectly from ngt_close(). 532 */ 533 static int 534 ngt_shutdown(node_p node) 535 { 536 const sc_p sc = node->private; 537 538 if (!ngt_nodeop_ok) 539 return (EOPNOTSUPP); 540 ng_unname(node); 541 ng_cutlinks(node); 542 node->private = NULL; 543 ng_unref(sc->node); 544 m_freem(sc->qhead); 545 m_freem(sc->m); 546 bzero(sc, sizeof(*sc)); 547 FREE(sc, M_NETGRAPH); 548 return (0); 549 } 550 551 /* 552 * Receive incoming data from netgraph system. Put it on our 553 * output queue and start output if necessary. 554 */ 555 static int 556 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 557 { 558 const sc_p sc = hook->node->private; 559 int error = 0; 560 561 if (hook != sc->hook) 562 panic(__func__); 563 NG_FREE_META(meta); 564 crit_enter(); 565 if (sc->qlen >= MAX_MBUFQ) 566 ERROUT(ENOBUFS); 567 m->m_nextpkt = NULL; 568 *sc->qtail = m; 569 sc->qtail = &m->m_nextpkt; 570 sc->qlen++; 571 QUEUECHECK(sc); 572 m = NULL; 573 if (sc->qlen == 1) 574 ngt_start(sc->tp); 575 done: 576 crit_exit(); 577 if (m) 578 m_freem(m); 579 return (error); 580 } 581 582 /* 583 * Receive control message 584 */ 585 static int 586 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 587 struct ng_mesg **rptr) 588 { 589 const sc_p sc = (sc_p) node->private; 590 struct ng_mesg *resp = NULL; 591 int error = 0; 592 593 switch (msg->header.typecookie) { 594 case NGM_TTY_COOKIE: 595 switch (msg->header.cmd) { 596 case NGM_TTY_SET_HOTCHAR: 597 { 598 int hotchar; 599 600 if (msg->header.arglen != sizeof(int)) 601 ERROUT(EINVAL); 602 hotchar = *((int *) msg->data); 603 if (hotchar != (u_char) hotchar && hotchar != -1) 604 ERROUT(EINVAL); 605 sc->hotchar = hotchar; /* race condition is OK */ 606 break; 607 } 608 case NGM_TTY_GET_HOTCHAR: 609 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 610 if (!resp) 611 ERROUT(ENOMEM); 612 /* Race condition here is OK */ 613 *((int *) resp->data) = sc->hotchar; 614 break; 615 default: 616 ERROUT(EINVAL); 617 } 618 break; 619 default: 620 ERROUT(EINVAL); 621 } 622 if (rptr) 623 *rptr = resp; 624 else if (resp) 625 FREE(resp, M_NETGRAPH); 626 627 done: 628 FREE(msg, M_NETGRAPH); 629 return (error); 630 } 631 632 /****************************************************************** 633 INITIALIZATION 634 ******************************************************************/ 635 636 /* 637 * Handle loading and unloading for this node type 638 */ 639 static int 640 ngt_mod_event(module_t mod, int event, void *data) 641 { 642 /* struct ng_type *const type = data;*/ 643 int error = 0; 644 645 switch (event) { 646 case MOD_LOAD: 647 /* Register line discipline */ 648 crit_enter(); 649 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 650 crit_exit(); 651 log(LOG_ERR, "%s: can't register line discipline", 652 __func__); 653 return (EIO); 654 } 655 crit_exit(); 656 break; 657 658 case MOD_UNLOAD: 659 660 /* Unregister line discipline */ 661 crit_enter(); 662 ldisc_deregister(ngt_ldisc); 663 crit_exit(); 664 break; 665 666 default: 667 error = EOPNOTSUPP; 668 break; 669 } 670 return (error); 671 } 672 673