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 1.12 2006/07/28 02:17:40 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 #ifdef __i386__ /* fiddle with the spl locking */ 82 #include <machine/ipl.h> 83 #include <i386/isa/intr_machdep.h> 84 #endif 85 86 /* Misc defs */ 87 #define MAX_MBUFQ 3 /* Max number of queued mbufs */ 88 #define NGT_HIWATER 400 /* High water mark on output */ 89 90 /* Per-node private info */ 91 struct ngt_sc { 92 struct tty *tp; /* Terminal device */ 93 node_p node; /* Netgraph node */ 94 hook_p hook; /* Netgraph hook */ 95 struct mbuf *m; /* Incoming data buffer */ 96 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */ 97 short qlen; /* Length of queue */ 98 short hotchar; /* Hotchar, or -1 if none */ 99 u_int flags; /* Flags */ 100 struct callout ctimeout; /* See man timeout(9) */ 101 }; 102 typedef struct ngt_sc *sc_p; 103 104 /* Flags */ 105 #define FLG_TIMEOUT 0x0001 /* A timeout is pending */ 106 #define FLG_DEBUG 0x0002 107 108 /* Debugging */ 109 #ifdef INVARIANTS 110 #define QUEUECHECK(sc) \ 111 do { \ 112 struct mbuf **mp; \ 113 int k; \ 114 \ 115 for (k = 0, mp = &sc->qhead; \ 116 k <= MAX_MBUFQ && *mp; \ 117 k++, mp = &(*mp)->m_nextpkt); \ 118 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \ 119 panic("%s: queue", __func__); \ 120 } while (0) 121 #else 122 #define QUEUECHECK(sc) do {} while (0) 123 #endif 124 125 /* Line discipline methods */ 126 static int ngt_open(dev_t dev, struct tty *tp); 127 static int ngt_close(struct tty *tp, int flag); 128 static int ngt_read(struct tty *tp, struct uio *uio, int flag); 129 static int ngt_write(struct tty *tp, struct uio *uio, int flag); 130 static int ngt_tioctl(struct tty *tp, 131 u_long cmd, caddr_t data, int flag, struct ucred *cred); 132 static int ngt_input(int c, struct tty *tp); 133 static int ngt_start(struct tty *tp); 134 135 /* Netgraph methods */ 136 static ng_constructor_t ngt_constructor; 137 static ng_rcvmsg_t ngt_rcvmsg; 138 static ng_shutdown_t ngt_shutdown; 139 static ng_newhook_t ngt_newhook; 140 static ng_rcvdata_t ngt_rcvdata; 141 static ng_disconnect_t ngt_disconnect; 142 static int ngt_mod_event(module_t mod, int event, void *data); 143 144 /* Other stuff */ 145 static void ngt_timeout(void *arg); 146 147 #define ERROUT(x) do { error = (x); goto done; } while (0) 148 149 /* Line discipline descriptor */ 150 static struct linesw ngt_disc = { 151 ngt_open, 152 ngt_close, 153 ngt_read, 154 ngt_write, 155 ngt_tioctl, 156 ngt_input, 157 ngt_start, 158 ttymodem, 159 NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */ 160 }; 161 162 /* Netgraph node type descriptor */ 163 static struct ng_type typestruct = { 164 NG_VERSION, 165 NG_TTY_NODE_TYPE, 166 ngt_mod_event, 167 ngt_constructor, 168 ngt_rcvmsg, 169 ngt_shutdown, 170 ngt_newhook, 171 NULL, 172 NULL, 173 ngt_rcvdata, 174 ngt_rcvdata, 175 ngt_disconnect, 176 NULL 177 }; 178 NETGRAPH_INIT(tty, &typestruct); 179 180 static int ngt_unit; 181 static int ngt_nodeop_ok; /* OK to create/remove node */ 182 static int ngt_ldisc; 183 184 /****************************************************************** 185 LINE DISCIPLINE METHODS 186 ******************************************************************/ 187 188 /* 189 * Set our line discipline on the tty. 190 * Called from device open routine or ttioctl() at >= splsofttty() 191 */ 192 static int 193 ngt_open(dev_t dev, struct tty *tp) 194 { 195 struct thread *td = curthread; /* XXX */ 196 char name[sizeof(NG_TTY_NODE_TYPE) + 8]; 197 sc_p sc; 198 int error; 199 200 /* Super-user only */ 201 if ((error = suser(td))) 202 return (error); 203 crit_enter(); 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 crit_exit(); 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; 273 274 crit_enter(); 275 ttyflush(tp, FREAD | FWRITE); 276 clist_free_cblocks(&tp->t_outq); 277 tp->t_line = 0; 278 if (sc != NULL) { 279 if (sc->flags & FLG_TIMEOUT) { 280 callout_stop(&sc->ctimeout); 281 sc->flags &= ~FLG_TIMEOUT; 282 } 283 ngt_nodeop_ok = 1; 284 ng_rmnode(sc->node); 285 ngt_nodeop_ok = 0; 286 tp->t_sc = NULL; 287 } 288 crit_exit(); 289 return (0); 290 } 291 292 /* 293 * Once the device has been turned into a node, we don't allow reading. 294 */ 295 static int 296 ngt_read(struct tty *tp, struct uio *uio, int flag) 297 { 298 return (EIO); 299 } 300 301 /* 302 * Once the device has been turned into a node, we don't allow writing. 303 */ 304 static int 305 ngt_write(struct tty *tp, struct uio *uio, int flag) 306 { 307 return (EIO); 308 } 309 310 /* 311 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 312 */ 313 static int 314 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred) 315 { 316 const sc_p sc = (sc_p) tp->t_sc; 317 int error = 0; 318 319 crit_enter(); 320 switch (cmd) { 321 case NGIOCGINFO: 322 { 323 struct nodeinfo *const ni = (struct nodeinfo *) data; 324 const node_p node = sc->node; 325 326 bzero(ni, sizeof(*ni)); 327 if (node->name) 328 strncpy(ni->name, node->name, sizeof(ni->name) - 1); 329 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1); 330 ni->id = (u_int32_t) node; 331 ni->hooks = node->numhooks; 332 break; 333 } 334 default: 335 ERROUT(ENOIOCTL); 336 } 337 done: 338 crit_exit(); 339 return (error); 340 } 341 342 /* 343 * Receive data coming from the device. We get one character at 344 * a time, which is kindof silly. 345 * Only guaranteed to be at splsofttty() or spltty(). 346 */ 347 static int 348 ngt_input(int c, struct tty *tp) 349 { 350 const sc_p sc = (sc_p) tp->t_sc; 351 const node_p node = sc->node; 352 struct mbuf *m; 353 int error = 0; 354 355 if (!sc || tp != sc->tp) 356 return (0); 357 crit_enter(); 358 if (!sc->hook) 359 ERROUT(0); 360 361 /* Check for error conditions */ 362 if ((tp->t_state & TS_CONNECTED) == 0) { 363 if (sc->flags & FLG_DEBUG) 364 log(LOG_DEBUG, "%s: no carrier\n", node->name); 365 ERROUT(0); 366 } 367 if (c & TTY_ERRORMASK) { 368 /* framing error or overrun on this char */ 369 if (sc->flags & FLG_DEBUG) 370 log(LOG_DEBUG, "%s: line error %x\n", 371 node->name, c & TTY_ERRORMASK); 372 ERROUT(0); 373 } 374 c &= TTY_CHARMASK; 375 376 /* Get a new header mbuf if we need one */ 377 if (!(m = sc->m)) { 378 MGETHDR(m, MB_DONTWAIT, MT_DATA); 379 if (!m) { 380 if (sc->flags & FLG_DEBUG) 381 log(LOG_ERR, 382 "%s: can't get mbuf\n", node->name); 383 ERROUT(ENOBUFS); 384 } 385 m->m_len = m->m_pkthdr.len = 0; 386 m->m_pkthdr.rcvif = NULL; 387 sc->m = m; 388 } 389 390 /* Add char to mbuf */ 391 *mtod(m, u_char *) = c; 392 m->m_data++; 393 m->m_len++; 394 m->m_pkthdr.len++; 395 396 /* Ship off mbuf if it's time */ 397 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 398 m->m_data = m->m_pktdat; 399 error = ng_queue_data(sc->hook, m, NULL); 400 sc->m = NULL; 401 } 402 done: 403 crit_exit(); 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 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 419 struct mbuf *m = sc->qhead; 420 421 /* Remove first mbuf from queue */ 422 if (!m) 423 break; 424 if ((sc->qhead = m->m_nextpkt) == NULL) 425 sc->qtail = &sc->qhead; 426 sc->qlen--; 427 QUEUECHECK(sc); 428 429 /* Send as much of it as possible */ 430 while (m) { 431 int sent; 432 433 sent = m->m_len 434 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq); 435 m->m_data += sent; 436 m->m_len -= sent; 437 if (m->m_len > 0) 438 break; /* device can't take no more */ 439 m = m_free(m); 440 } 441 442 /* Put remainder of mbuf chain (if any) back on queue */ 443 if (m) { 444 m->m_nextpkt = sc->qhead; 445 sc->qhead = m; 446 if (sc->qtail == &sc->qhead) 447 sc->qtail = &m->m_nextpkt; 448 sc->qlen++; 449 QUEUECHECK(sc); 450 break; 451 } 452 } 453 454 /* Call output process whether or not there is any output. We are 455 * being called in lieu of ttstart and must do what it would. */ 456 if (tp->t_oproc != NULL) 457 (*tp->t_oproc) (tp); 458 459 /* This timeout is needed for operation on a pseudo-tty, because the 460 * pty code doesn't call pppstart after it has drained the t_outq. */ 461 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 462 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc); 463 sc->flags |= FLG_TIMEOUT; 464 } 465 crit_exit(); 466 return (0); 467 } 468 469 /* 470 * We still have data to output to the device, so try sending more. 471 */ 472 static void 473 ngt_timeout(void *arg) 474 { 475 const sc_p sc = (sc_p) arg; 476 477 crit_enter(); 478 sc->flags &= ~FLG_TIMEOUT; 479 ngt_start(sc->tp); 480 crit_exit(); 481 } 482 483 /****************************************************************** 484 NETGRAPH NODE METHODS 485 ******************************************************************/ 486 487 /* 488 * Initialize a new node of this type. 489 * 490 * We only allow nodes to be created as a result of setting 491 * the line discipline on a tty, so always return an error if not. 492 */ 493 static int 494 ngt_constructor(node_p *nodep) 495 { 496 if (!ngt_nodeop_ok) 497 return (EOPNOTSUPP); 498 return (ng_make_node_common(&typestruct, nodep)); 499 } 500 501 /* 502 * Add a new hook. There can only be one. 503 */ 504 static int 505 ngt_newhook(node_p node, hook_p hook, const char *name) 506 { 507 const sc_p sc = node->private; 508 int error = 0; 509 510 if (strcmp(name, NG_TTY_HOOK)) 511 return (EINVAL); 512 crit_enter(); 513 if (sc->hook) 514 ERROUT(EISCONN); 515 sc->hook = hook; 516 done: 517 crit_exit(); 518 return (error); 519 } 520 521 /* 522 * Disconnect the hook 523 */ 524 static int 525 ngt_disconnect(hook_p hook) 526 { 527 const sc_p sc = hook->node->private; 528 529 crit_enter(); 530 if (hook != sc->hook) 531 panic(__func__); 532 sc->hook = NULL; 533 m_freem(sc->m); 534 sc->m = NULL; 535 crit_exit(); 536 return (0); 537 } 538 539 /* 540 * Remove this node. The does the netgraph portion of the shutdown. 541 * This should only be called indirectly from ngt_close(). 542 */ 543 static int 544 ngt_shutdown(node_p node) 545 { 546 const sc_p sc = node->private; 547 548 if (!ngt_nodeop_ok) 549 return (EOPNOTSUPP); 550 ng_unname(node); 551 ng_cutlinks(node); 552 node->private = NULL; 553 ng_unref(sc->node); 554 m_freem(sc->qhead); 555 m_freem(sc->m); 556 bzero(sc, sizeof(*sc)); 557 FREE(sc, M_NETGRAPH); 558 return (0); 559 } 560 561 /* 562 * Receive incoming data from netgraph system. Put it on our 563 * output queue and start output if necessary. 564 */ 565 static int 566 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 567 { 568 const sc_p sc = hook->node->private; 569 int error = 0; 570 571 if (hook != sc->hook) 572 panic(__func__); 573 NG_FREE_META(meta); 574 crit_enter(); 575 if (sc->qlen >= MAX_MBUFQ) 576 ERROUT(ENOBUFS); 577 m->m_nextpkt = NULL; 578 *sc->qtail = m; 579 sc->qtail = &m->m_nextpkt; 580 sc->qlen++; 581 QUEUECHECK(sc); 582 m = NULL; 583 if (sc->qlen == 1) 584 ngt_start(sc->tp); 585 done: 586 crit_exit(); 587 if (m) 588 m_freem(m); 589 return (error); 590 } 591 592 /* 593 * Receive control message 594 */ 595 static int 596 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 597 struct ng_mesg **rptr) 598 { 599 const sc_p sc = (sc_p) node->private; 600 struct ng_mesg *resp = NULL; 601 int error = 0; 602 603 switch (msg->header.typecookie) { 604 case NGM_TTY_COOKIE: 605 switch (msg->header.cmd) { 606 case NGM_TTY_SET_HOTCHAR: 607 { 608 int hotchar; 609 610 if (msg->header.arglen != sizeof(int)) 611 ERROUT(EINVAL); 612 hotchar = *((int *) msg->data); 613 if (hotchar != (u_char) hotchar && hotchar != -1) 614 ERROUT(EINVAL); 615 sc->hotchar = hotchar; /* race condition is OK */ 616 break; 617 } 618 case NGM_TTY_GET_HOTCHAR: 619 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 620 if (!resp) 621 ERROUT(ENOMEM); 622 /* Race condition here is OK */ 623 *((int *) resp->data) = sc->hotchar; 624 break; 625 default: 626 ERROUT(EINVAL); 627 } 628 break; 629 default: 630 ERROUT(EINVAL); 631 } 632 if (rptr) 633 *rptr = resp; 634 else if (resp) 635 FREE(resp, M_NETGRAPH); 636 637 done: 638 FREE(msg, M_NETGRAPH); 639 return (error); 640 } 641 642 /****************************************************************** 643 INITIALIZATION 644 ******************************************************************/ 645 646 /* 647 * Handle loading and unloading for this node type 648 */ 649 static int 650 ngt_mod_event(module_t mod, int event, void *data) 651 { 652 /* struct ng_type *const type = data;*/ 653 int error = 0; 654 655 switch (event) { 656 case MOD_LOAD: 657 /* Register line discipline */ 658 crit_enter(); 659 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 660 crit_exit(); 661 log(LOG_ERR, "%s: can't register line discipline", 662 __func__); 663 return (EIO); 664 } 665 crit_exit(); 666 break; 667 668 case MOD_UNLOAD: 669 670 /* Unregister line discipline */ 671 crit_enter(); 672 ldisc_deregister(ngt_ldisc); 673 crit_exit(); 674 break; 675 676 default: 677 error = EOPNOTSUPP; 678 break; 679 } 680 return (error); 681 } 682 683