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/ioccom.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(); 200 201 /* 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 MALLOC(sc, sc_p, 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(&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 FREE(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 crit_exit(); 252 return (error); 253 } 254 255 /* 256 * Line specific close routine, called from device close routine 257 * and from ttioctl at >= splsofttty(). This causes the node to 258 * be destroyed as well. 259 */ 260 static int 261 ngt_close(struct tty *tp, int flag) 262 { 263 const sc_p sc = (sc_p) tp->t_sc; 264 265 crit_enter(); 266 ttyflush(tp, FREAD | FWRITE); 267 clist_free_cblocks(&tp->t_outq); 268 tp->t_line = 0; 269 if (sc != NULL) { 270 if (sc->flags & FLG_TIMEOUT) { 271 callout_stop(&sc->ctimeout); 272 sc->flags &= ~FLG_TIMEOUT; 273 } 274 ngt_nodeop_ok = 1; 275 ng_rmnode(sc->node); 276 ngt_nodeop_ok = 0; 277 tp->t_sc = NULL; 278 } 279 crit_exit(); 280 return (0); 281 } 282 283 /* 284 * Once the device has been turned into a node, we don't allow reading. 285 */ 286 static int 287 ngt_read(struct tty *tp, struct uio *uio, int flag) 288 { 289 return (EIO); 290 } 291 292 /* 293 * Once the device has been turned into a node, we don't allow writing. 294 */ 295 static int 296 ngt_write(struct tty *tp, struct uio *uio, int flag) 297 { 298 return (EIO); 299 } 300 301 /* 302 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 303 */ 304 static int 305 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred) 306 { 307 const sc_p sc = (sc_p) tp->t_sc; 308 int error = 0; 309 310 crit_enter(); 311 switch (cmd) { 312 case NGIOCGINFO: 313 { 314 struct nodeinfo *const ni = (struct nodeinfo *) data; 315 const node_p node = sc->node; 316 317 bzero(ni, sizeof(*ni)); 318 if (node->name) 319 strncpy(ni->name, node->name, sizeof(ni->name) - 1); 320 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1); 321 ni->id = (u_int32_t) node; 322 ni->hooks = node->numhooks; 323 break; 324 } 325 default: 326 ERROUT(ENOIOCTL); 327 } 328 done: 329 crit_exit(); 330 return (error); 331 } 332 333 /* 334 * Receive data coming from the device. We get one character at 335 * a time, which is kindof silly. 336 * Only guaranteed to be at splsofttty() or spltty(). 337 */ 338 static int 339 ngt_input(int c, struct tty *tp) 340 { 341 const sc_p sc = (sc_p) tp->t_sc; 342 const node_p node = sc->node; 343 struct mbuf *m; 344 int error = 0; 345 346 if (!sc || tp != sc->tp) 347 return (0); 348 crit_enter(); 349 if (!sc->hook) 350 ERROUT(0); 351 352 /* Check for error conditions */ 353 if ((tp->t_state & TS_CONNECTED) == 0) { 354 if (sc->flags & FLG_DEBUG) 355 log(LOG_DEBUG, "%s: no carrier\n", node->name); 356 ERROUT(0); 357 } 358 if (c & TTY_ERRORMASK) { 359 /* framing error or overrun on this char */ 360 if (sc->flags & FLG_DEBUG) 361 log(LOG_DEBUG, "%s: line error %x\n", 362 node->name, c & TTY_ERRORMASK); 363 ERROUT(0); 364 } 365 c &= TTY_CHARMASK; 366 367 /* Get a new header mbuf if we need one */ 368 if (!(m = sc->m)) { 369 MGETHDR(m, MB_DONTWAIT, MT_DATA); 370 if (!m) { 371 if (sc->flags & FLG_DEBUG) 372 log(LOG_ERR, 373 "%s: can't get mbuf\n", node->name); 374 ERROUT(ENOBUFS); 375 } 376 m->m_len = m->m_pkthdr.len = 0; 377 m->m_pkthdr.rcvif = NULL; 378 sc->m = m; 379 } 380 381 /* Add char to mbuf */ 382 *mtod(m, u_char *) = c; 383 m->m_data++; 384 m->m_len++; 385 m->m_pkthdr.len++; 386 387 /* Ship off mbuf if it's time */ 388 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 389 m->m_data = m->m_pktdat; 390 error = ng_queue_data(sc->hook, m, NULL); 391 sc->m = NULL; 392 } 393 done: 394 crit_exit(); 395 return (error); 396 } 397 398 /* 399 * This is called when the device driver is ready for more output. 400 * Called from tty system at splsofttty() or spltty(). 401 * Also call from ngt_rcv_data() when a new mbuf is available for output. 402 */ 403 static int 404 ngt_start(struct tty *tp) 405 { 406 const sc_p sc = (sc_p) tp->t_sc; 407 408 crit_enter(); 409 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 410 struct mbuf *m = sc->qhead; 411 412 /* Remove first mbuf from queue */ 413 if (!m) 414 break; 415 if ((sc->qhead = m->m_nextpkt) == NULL) 416 sc->qtail = &sc->qhead; 417 sc->qlen--; 418 QUEUECHECK(sc); 419 420 /* Send as much of it as possible */ 421 while (m) { 422 int sent; 423 424 sent = m->m_len 425 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq); 426 m->m_data += sent; 427 m->m_len -= sent; 428 if (m->m_len > 0) 429 break; /* device can't take no more */ 430 m = m_free(m); 431 } 432 433 /* Put remainder of mbuf chain (if any) back on queue */ 434 if (m) { 435 m->m_nextpkt = sc->qhead; 436 sc->qhead = m; 437 if (sc->qtail == &sc->qhead) 438 sc->qtail = &m->m_nextpkt; 439 sc->qlen++; 440 QUEUECHECK(sc); 441 break; 442 } 443 } 444 445 /* Call output process whether or not there is any output. We are 446 * being called in lieu of ttstart and must do what it would. */ 447 if (tp->t_oproc != NULL) 448 (*tp->t_oproc) (tp); 449 450 /* This timeout is needed for operation on a pseudo-tty, because the 451 * pty code doesn't call pppstart after it has drained the t_outq. */ 452 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 453 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc); 454 sc->flags |= FLG_TIMEOUT; 455 } 456 crit_exit(); 457 return (0); 458 } 459 460 /* 461 * We still have data to output to the device, so try sending more. 462 */ 463 static void 464 ngt_timeout(void *arg) 465 { 466 const sc_p sc = (sc_p) arg; 467 468 crit_enter(); 469 sc->flags &= ~FLG_TIMEOUT; 470 ngt_start(sc->tp); 471 crit_exit(); 472 } 473 474 /****************************************************************** 475 NETGRAPH NODE METHODS 476 ******************************************************************/ 477 478 /* 479 * Initialize a new node of this type. 480 * 481 * We only allow nodes to be created as a result of setting 482 * the line discipline on a tty, so always return an error if not. 483 */ 484 static int 485 ngt_constructor(node_p *nodep) 486 { 487 if (!ngt_nodeop_ok) 488 return (EOPNOTSUPP); 489 return (ng_make_node_common(&typestruct, nodep)); 490 } 491 492 /* 493 * Add a new hook. There can only be one. 494 */ 495 static int 496 ngt_newhook(node_p node, hook_p hook, const char *name) 497 { 498 const sc_p sc = node->private; 499 int error = 0; 500 501 if (strcmp(name, NG_TTY_HOOK)) 502 return (EINVAL); 503 crit_enter(); 504 if (sc->hook) 505 ERROUT(EISCONN); 506 sc->hook = hook; 507 done: 508 crit_exit(); 509 return (error); 510 } 511 512 /* 513 * Disconnect the hook 514 */ 515 static int 516 ngt_disconnect(hook_p hook) 517 { 518 const sc_p sc = hook->node->private; 519 520 crit_enter(); 521 if (hook != sc->hook) 522 panic(__func__); 523 sc->hook = NULL; 524 m_freem(sc->m); 525 sc->m = NULL; 526 crit_exit(); 527 return (0); 528 } 529 530 /* 531 * Remove this node. The does the netgraph portion of the shutdown. 532 * This should only be called indirectly from ngt_close(). 533 */ 534 static int 535 ngt_shutdown(node_p node) 536 { 537 const sc_p sc = node->private; 538 539 if (!ngt_nodeop_ok) 540 return (EOPNOTSUPP); 541 ng_unname(node); 542 ng_cutlinks(node); 543 node->private = NULL; 544 ng_unref(sc->node); 545 m_freem(sc->qhead); 546 m_freem(sc->m); 547 bzero(sc, sizeof(*sc)); 548 FREE(sc, M_NETGRAPH); 549 return (0); 550 } 551 552 /* 553 * Receive incoming data from netgraph system. Put it on our 554 * output queue and start output if necessary. 555 */ 556 static int 557 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 558 { 559 const sc_p sc = hook->node->private; 560 int error = 0; 561 562 if (hook != sc->hook) 563 panic(__func__); 564 NG_FREE_META(meta); 565 crit_enter(); 566 if (sc->qlen >= MAX_MBUFQ) 567 ERROUT(ENOBUFS); 568 m->m_nextpkt = NULL; 569 *sc->qtail = m; 570 sc->qtail = &m->m_nextpkt; 571 sc->qlen++; 572 QUEUECHECK(sc); 573 m = NULL; 574 if (sc->qlen == 1) 575 ngt_start(sc->tp); 576 done: 577 crit_exit(); 578 if (m) 579 m_freem(m); 580 return (error); 581 } 582 583 /* 584 * Receive control message 585 */ 586 static int 587 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 588 struct ng_mesg **rptr) 589 { 590 const sc_p sc = (sc_p) node->private; 591 struct ng_mesg *resp = NULL; 592 int error = 0; 593 594 switch (msg->header.typecookie) { 595 case NGM_TTY_COOKIE: 596 switch (msg->header.cmd) { 597 case NGM_TTY_SET_HOTCHAR: 598 { 599 int hotchar; 600 601 if (msg->header.arglen != sizeof(int)) 602 ERROUT(EINVAL); 603 hotchar = *((int *) msg->data); 604 if (hotchar != (u_char) hotchar && hotchar != -1) 605 ERROUT(EINVAL); 606 sc->hotchar = hotchar; /* race condition is OK */ 607 break; 608 } 609 case NGM_TTY_GET_HOTCHAR: 610 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 611 if (!resp) 612 ERROUT(ENOMEM); 613 /* Race condition here is OK */ 614 *((int *) resp->data) = sc->hotchar; 615 break; 616 default: 617 ERROUT(EINVAL); 618 } 619 break; 620 default: 621 ERROUT(EINVAL); 622 } 623 if (rptr) 624 *rptr = resp; 625 else if (resp) 626 FREE(resp, M_NETGRAPH); 627 628 done: 629 FREE(msg, M_NETGRAPH); 630 return (error); 631 } 632 633 /****************************************************************** 634 INITIALIZATION 635 ******************************************************************/ 636 637 /* 638 * Handle loading and unloading for this node type 639 */ 640 static int 641 ngt_mod_event(module_t mod, int event, void *data) 642 { 643 /* struct ng_type *const type = data;*/ 644 int error = 0; 645 646 switch (event) { 647 case MOD_LOAD: 648 /* Register line discipline */ 649 crit_enter(); 650 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 651 crit_exit(); 652 log(LOG_ERR, "%s: can't register line discipline", 653 __func__); 654 return (EIO); 655 } 656 crit_exit(); 657 break; 658 659 case MOD_UNLOAD: 660 661 /* Unregister line discipline */ 662 crit_enter(); 663 ldisc_deregister(ngt_ldisc); 664 crit_exit(); 665 break; 666 667 default: 668 error = EOPNOTSUPP; 669 break; 670 } 671 return (error); 672 } 673 674