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 1.17 2006/12/20 18:14:43 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/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 #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 = suser(td))) 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); 209 if (sc == NULL) { 210 error = ENOMEM; 211 goto done; 212 } 213 bzero(sc, sizeof(*sc)); 214 sc->tp = tp; 215 sc->hotchar = NG_TTY_DFL_HOTCHAR; 216 sc->qtail = &sc->qhead; 217 QUEUECHECK(sc); 218 callout_init(&sc->ctimeout); 219 220 /* Setup netgraph node */ 221 ngt_nodeop_ok = 1; 222 error = ng_make_node_common(&typestruct, &sc->node); 223 ngt_nodeop_ok = 0; 224 if (error) { 225 FREE(sc, M_NETGRAPH); 226 goto done; 227 } 228 ksnprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++); 229 230 /* Set back pointers */ 231 sc->node->private = sc; 232 tp->t_sc = (caddr_t) sc; 233 234 /* Assign node its name */ 235 if ((error = ng_name_node(sc->node, name))) { 236 log(LOG_ERR, "%s: node name exists?\n", name); 237 ngt_nodeop_ok = 1; 238 ng_rmnode(sc->node); 239 ngt_nodeop_ok = 0; 240 goto done; 241 } 242 243 /* 244 * Pre-allocate cblocks to the an appropriate amount. 245 * I'm not sure what is appropriate. 246 */ 247 ttyflush(tp, FREAD | FWRITE); 248 clist_alloc_cblocks(&tp->t_canq, 0, 0); 249 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 250 clist_alloc_cblocks(&tp->t_outq, 251 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER); 252 253 done: 254 /* Done */ 255 crit_exit(); 256 return (error); 257 } 258 259 /* 260 * Line specific close routine, called from device close routine 261 * and from ttioctl at >= splsofttty(). This causes the node to 262 * be destroyed as well. 263 */ 264 static int 265 ngt_close(struct tty *tp, int flag) 266 { 267 const sc_p sc = (sc_p) tp->t_sc; 268 269 crit_enter(); 270 ttyflush(tp, FREAD | FWRITE); 271 clist_free_cblocks(&tp->t_outq); 272 tp->t_line = 0; 273 if (sc != NULL) { 274 if (sc->flags & FLG_TIMEOUT) { 275 callout_stop(&sc->ctimeout); 276 sc->flags &= ~FLG_TIMEOUT; 277 } 278 ngt_nodeop_ok = 1; 279 ng_rmnode(sc->node); 280 ngt_nodeop_ok = 0; 281 tp->t_sc = NULL; 282 } 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 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) node; 326 ni->hooks = node->numhooks; 327 break; 328 } 329 default: 330 ERROUT(ENOIOCTL); 331 } 332 done: 333 crit_exit(); 334 return (error); 335 } 336 337 /* 338 * Receive data coming from the device. We get one character at 339 * a time, which is kindof silly. 340 * Only guaranteed to be at splsofttty() or spltty(). 341 */ 342 static int 343 ngt_input(int c, struct tty *tp) 344 { 345 const sc_p sc = (sc_p) tp->t_sc; 346 const node_p node = sc->node; 347 struct mbuf *m; 348 int error = 0; 349 350 if (!sc || tp != sc->tp) 351 return (0); 352 crit_enter(); 353 if (!sc->hook) 354 ERROUT(0); 355 356 /* Check for error conditions */ 357 if ((tp->t_state & TS_CONNECTED) == 0) { 358 if (sc->flags & FLG_DEBUG) 359 log(LOG_DEBUG, "%s: no carrier\n", node->name); 360 ERROUT(0); 361 } 362 if (c & TTY_ERRORMASK) { 363 /* framing error or overrun on this char */ 364 if (sc->flags & FLG_DEBUG) 365 log(LOG_DEBUG, "%s: line error %x\n", 366 node->name, c & TTY_ERRORMASK); 367 ERROUT(0); 368 } 369 c &= TTY_CHARMASK; 370 371 /* Get a new header mbuf if we need one */ 372 if (!(m = sc->m)) { 373 MGETHDR(m, MB_DONTWAIT, MT_DATA); 374 if (!m) { 375 if (sc->flags & FLG_DEBUG) 376 log(LOG_ERR, 377 "%s: can't get mbuf\n", node->name); 378 ERROUT(ENOBUFS); 379 } 380 m->m_len = m->m_pkthdr.len = 0; 381 m->m_pkthdr.rcvif = NULL; 382 sc->m = m; 383 } 384 385 /* Add char to mbuf */ 386 *mtod(m, u_char *) = c; 387 m->m_data++; 388 m->m_len++; 389 m->m_pkthdr.len++; 390 391 /* Ship off mbuf if it's time */ 392 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 393 m->m_data = m->m_pktdat; 394 error = ng_queue_data(sc->hook, m, NULL); 395 sc->m = NULL; 396 } 397 done: 398 crit_exit(); 399 return (error); 400 } 401 402 /* 403 * This is called when the device driver is ready for more output. 404 * Called from tty system at splsofttty() or spltty(). 405 * Also call from ngt_rcv_data() when a new mbuf is available for output. 406 */ 407 static int 408 ngt_start(struct tty *tp) 409 { 410 const sc_p sc = (sc_p) tp->t_sc; 411 412 crit_enter(); 413 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 414 struct mbuf *m = sc->qhead; 415 416 /* Remove first mbuf from queue */ 417 if (!m) 418 break; 419 if ((sc->qhead = m->m_nextpkt) == NULL) 420 sc->qtail = &sc->qhead; 421 sc->qlen--; 422 QUEUECHECK(sc); 423 424 /* Send as much of it as possible */ 425 while (m) { 426 int sent; 427 428 sent = m->m_len 429 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq); 430 m->m_data += sent; 431 m->m_len -= sent; 432 if (m->m_len > 0) 433 break; /* device can't take no more */ 434 m = m_free(m); 435 } 436 437 /* Put remainder of mbuf chain (if any) back on queue */ 438 if (m) { 439 m->m_nextpkt = sc->qhead; 440 sc->qhead = m; 441 if (sc->qtail == &sc->qhead) 442 sc->qtail = &m->m_nextpkt; 443 sc->qlen++; 444 QUEUECHECK(sc); 445 break; 446 } 447 } 448 449 /* Call output process whether or not there is any output. We are 450 * being called in lieu of ttstart and must do what it would. */ 451 if (tp->t_oproc != NULL) 452 (*tp->t_oproc) (tp); 453 454 /* This timeout is needed for operation on a pseudo-tty, because the 455 * pty code doesn't call pppstart after it has drained the t_outq. */ 456 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 457 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc); 458 sc->flags |= FLG_TIMEOUT; 459 } 460 crit_exit(); 461 return (0); 462 } 463 464 /* 465 * We still have data to output to the device, so try sending more. 466 */ 467 static void 468 ngt_timeout(void *arg) 469 { 470 const sc_p sc = (sc_p) arg; 471 472 crit_enter(); 473 sc->flags &= ~FLG_TIMEOUT; 474 ngt_start(sc->tp); 475 crit_exit(); 476 } 477 478 /****************************************************************** 479 NETGRAPH NODE METHODS 480 ******************************************************************/ 481 482 /* 483 * Initialize a new node of this type. 484 * 485 * We only allow nodes to be created as a result of setting 486 * the line discipline on a tty, so always return an error if not. 487 */ 488 static int 489 ngt_constructor(node_p *nodep) 490 { 491 if (!ngt_nodeop_ok) 492 return (EOPNOTSUPP); 493 return (ng_make_node_common(&typestruct, nodep)); 494 } 495 496 /* 497 * Add a new hook. There can only be one. 498 */ 499 static int 500 ngt_newhook(node_p node, hook_p hook, const char *name) 501 { 502 const sc_p sc = node->private; 503 int error = 0; 504 505 if (strcmp(name, NG_TTY_HOOK)) 506 return (EINVAL); 507 crit_enter(); 508 if (sc->hook) 509 ERROUT(EISCONN); 510 sc->hook = hook; 511 done: 512 crit_exit(); 513 return (error); 514 } 515 516 /* 517 * Disconnect the hook 518 */ 519 static int 520 ngt_disconnect(hook_p hook) 521 { 522 const sc_p sc = hook->node->private; 523 524 crit_enter(); 525 if (hook != sc->hook) 526 panic(__func__); 527 sc->hook = NULL; 528 m_freem(sc->m); 529 sc->m = NULL; 530 crit_exit(); 531 return (0); 532 } 533 534 /* 535 * Remove this node. The does the netgraph portion of the shutdown. 536 * This should only be called indirectly from ngt_close(). 537 */ 538 static int 539 ngt_shutdown(node_p node) 540 { 541 const sc_p sc = node->private; 542 543 if (!ngt_nodeop_ok) 544 return (EOPNOTSUPP); 545 ng_unname(node); 546 ng_cutlinks(node); 547 node->private = NULL; 548 ng_unref(sc->node); 549 m_freem(sc->qhead); 550 m_freem(sc->m); 551 bzero(sc, sizeof(*sc)); 552 FREE(sc, M_NETGRAPH); 553 return (0); 554 } 555 556 /* 557 * Receive incoming data from netgraph system. Put it on our 558 * output queue and start output if necessary. 559 */ 560 static int 561 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 562 { 563 const sc_p sc = hook->node->private; 564 int error = 0; 565 566 if (hook != sc->hook) 567 panic(__func__); 568 NG_FREE_META(meta); 569 crit_enter(); 570 if (sc->qlen >= MAX_MBUFQ) 571 ERROUT(ENOBUFS); 572 m->m_nextpkt = NULL; 573 *sc->qtail = m; 574 sc->qtail = &m->m_nextpkt; 575 sc->qlen++; 576 QUEUECHECK(sc); 577 m = NULL; 578 if (sc->qlen == 1) 579 ngt_start(sc->tp); 580 done: 581 crit_exit(); 582 if (m) 583 m_freem(m); 584 return (error); 585 } 586 587 /* 588 * Receive control message 589 */ 590 static int 591 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 592 struct ng_mesg **rptr) 593 { 594 const sc_p sc = (sc_p) node->private; 595 struct ng_mesg *resp = NULL; 596 int error = 0; 597 598 switch (msg->header.typecookie) { 599 case NGM_TTY_COOKIE: 600 switch (msg->header.cmd) { 601 case NGM_TTY_SET_HOTCHAR: 602 { 603 int hotchar; 604 605 if (msg->header.arglen != sizeof(int)) 606 ERROUT(EINVAL); 607 hotchar = *((int *) msg->data); 608 if (hotchar != (u_char) hotchar && hotchar != -1) 609 ERROUT(EINVAL); 610 sc->hotchar = hotchar; /* race condition is OK */ 611 break; 612 } 613 case NGM_TTY_GET_HOTCHAR: 614 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 615 if (!resp) 616 ERROUT(ENOMEM); 617 /* Race condition here is OK */ 618 *((int *) resp->data) = sc->hotchar; 619 break; 620 default: 621 ERROUT(EINVAL); 622 } 623 break; 624 default: 625 ERROUT(EINVAL); 626 } 627 if (rptr) 628 *rptr = resp; 629 else if (resp) 630 FREE(resp, M_NETGRAPH); 631 632 done: 633 FREE(msg, M_NETGRAPH); 634 return (error); 635 } 636 637 /****************************************************************** 638 INITIALIZATION 639 ******************************************************************/ 640 641 /* 642 * Handle loading and unloading for this node type 643 */ 644 static int 645 ngt_mod_event(module_t mod, int event, void *data) 646 { 647 /* struct ng_type *const type = data;*/ 648 int error = 0; 649 650 switch (event) { 651 case MOD_LOAD: 652 /* Register line discipline */ 653 crit_enter(); 654 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 655 crit_exit(); 656 log(LOG_ERR, "%s: can't register line discipline", 657 __func__); 658 return (EIO); 659 } 660 crit_exit(); 661 break; 662 663 case MOD_UNLOAD: 664 665 /* Unregister line discipline */ 666 crit_enter(); 667 ldisc_deregister(ngt_ldisc); 668 crit_exit(); 669 break; 670 671 default: 672 error = EOPNOTSUPP; 673 break; 674 } 675 return (error); 676 } 677 678