1 /* 2 * (MPSAFE) 3 * 4 * ng_tty.c 5 * 6 * Copyright (c) 1996-1999 Whistle Communications, Inc. 7 * All rights reserved. 8 * 9 * Subject to the following obligations and disclaimer of warranty, use and 10 * redistribution of this software, in source or object code forms, with or 11 * without modifications are expressly permitted by Whistle Communications; 12 * provided, however, that: 13 * 1. Any and all reproductions of the source or object code must include the 14 * copyright notice above and the following disclaimer of warranties; and 15 * 2. No rights are granted, in any manner or form, to use Whistle 16 * Communications, Inc. trademarks, including the mark "WHISTLE 17 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as 18 * such appears in the above copyright notice or in the software. 19 * 20 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND 21 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO 22 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, 23 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF 24 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. 25 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY 26 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS 27 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE. 28 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES 29 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING 30 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 31 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR 32 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY 36 * OF SUCH DAMAGE. 37 * 38 * Author: Archie Cobbs <archie@freebsd.org> 39 * 40 * $FreeBSD: src/sys/netgraph/ng_tty.c,v 1.7.2.3 2002/02/13 00:43:12 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/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 lwkt_gettoken(&tp->t_token); 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 sc = kmalloc(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_mp(&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 kfree(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); 244 clist_alloc_cblocks(&tp->t_rawq, 0); 245 clist_alloc_cblocks(&tp->t_outq, MLEN + NGT_HIWATER); 246 247 done: 248 /* Done */ 249 lwkt_reltoken(&tp->t_token); 250 return (error); 251 } 252 253 /* 254 * Line specific close routine, called from device close routine 255 * and from ttioctl at >= splsofttty(). This causes the node to 256 * be destroyed as well. 257 */ 258 static int 259 ngt_close(struct tty *tp, int flag) 260 { 261 const sc_p sc = (sc_p) tp->t_sc; 262 263 lwkt_gettoken(&tp->t_token); 264 ttyflush(tp, FREAD | FWRITE); 265 clist_free_cblocks(&tp->t_outq); 266 tp->t_line = 0; 267 if (sc != NULL) { 268 if (sc->flags & FLG_TIMEOUT) { 269 callout_stop(&sc->ctimeout); 270 sc->flags &= ~FLG_TIMEOUT; 271 } 272 ngt_nodeop_ok = 1; 273 ng_rmnode(sc->node); 274 ngt_nodeop_ok = 0; 275 tp->t_sc = NULL; 276 } 277 lwkt_reltoken(&tp->t_token); 278 279 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 lwkt_gettoken(&tp->t_token); 310 311 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)(uintptr_t)node; 322 ni->hooks = node->numhooks; 323 break; 324 } 325 default: 326 ERROUT(ENOIOCTL); 327 } 328 done: 329 lwkt_reltoken(&tp->t_token); 330 331 return (error); 332 } 333 334 /* 335 * Receive data coming from the device. We get one character at 336 * a time, which is kindof silly. 337 * Only guaranteed to be at splsofttty() or spltty(). 338 */ 339 static int 340 ngt_input(int c, struct tty *tp) 341 { 342 const sc_p sc = (sc_p) tp->t_sc; 343 const node_p node = sc ? sc->node : NULL; 344 struct mbuf *m; 345 int error = 0; 346 347 lwkt_gettoken(&tp->t_token); 348 if (!sc || tp != sc->tp) { 349 lwkt_reltoken(&tp->t_token); 350 return (0); 351 } 352 if (!sc->hook) 353 ERROUT(0); 354 355 /* Check for error conditions */ 356 if ((tp->t_state & TS_CONNECTED) == 0) { 357 if (sc->flags & FLG_DEBUG) 358 log(LOG_DEBUG, "%s: no carrier\n", node->name); 359 ERROUT(0); 360 } 361 if (c & TTY_ERRORMASK) { 362 /* framing error or overrun on this char */ 363 if (sc->flags & FLG_DEBUG) 364 log(LOG_DEBUG, "%s: line error %x\n", 365 node->name, c & TTY_ERRORMASK); 366 ERROUT(0); 367 } 368 c &= TTY_CHARMASK; 369 370 /* Get a new header mbuf if we need one */ 371 if (!(m = sc->m)) { 372 MGETHDR(m, M_NOWAIT, MT_DATA); 373 if (!m) { 374 if (sc->flags & FLG_DEBUG) 375 log(LOG_ERR, 376 "%s: can't get mbuf\n", node->name); 377 ERROUT(ENOBUFS); 378 } 379 m->m_len = m->m_pkthdr.len = 0; 380 m->m_pkthdr.rcvif = NULL; 381 sc->m = m; 382 } 383 384 /* Add char to mbuf */ 385 *mtod(m, u_char *) = c; 386 m->m_data++; 387 m->m_len++; 388 m->m_pkthdr.len++; 389 390 /* Ship off mbuf if it's time */ 391 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 392 m->m_data = m->m_pktdat; 393 error = ng_queue_data(sc->hook, m, NULL); 394 sc->m = NULL; 395 } 396 done: 397 lwkt_reltoken(&tp->t_token); 398 399 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 lwkt_gettoken(&tp->t_token); 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 - clist_btoq(mtod(m, u_char *), 429 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 lwkt_reltoken(&tp->t_token); 461 462 return (0); 463 } 464 465 /* 466 * We still have data to output to the device, so try sending more. 467 */ 468 static void 469 ngt_timeout(void *arg) 470 { 471 const sc_p sc = (sc_p) arg; 472 struct tty *tp = sc->tp; 473 474 lwkt_gettoken(&tp->t_token); 475 sc->flags &= ~FLG_TIMEOUT; 476 ngt_start(tp); 477 lwkt_reltoken(&tp->t_token); 478 } 479 480 /****************************************************************** 481 NETGRAPH NODE METHODS 482 ******************************************************************/ 483 484 /* 485 * Initialize a new node of this type. 486 * 487 * We only allow nodes to be created as a result of setting 488 * the line discipline on a tty, so always return an error if not. 489 */ 490 static int 491 ngt_constructor(node_p *nodep) 492 { 493 if (!ngt_nodeop_ok) 494 return (EOPNOTSUPP); 495 return (ng_make_node_common(&typestruct, nodep)); 496 } 497 498 /* 499 * Add a new hook. There can only be one. 500 */ 501 static int 502 ngt_newhook(node_p node, hook_p hook, const char *name) 503 { 504 const sc_p sc = node->private; 505 struct tty *tp = sc->tp; 506 int error = 0; 507 508 if (strcmp(name, NG_TTY_HOOK)) 509 return (EINVAL); 510 lwkt_gettoken(&tp->t_token); 511 if (sc->hook) 512 ERROUT(EISCONN); 513 sc->hook = hook; 514 done: 515 lwkt_reltoken(&tp->t_token); 516 517 return (error); 518 } 519 520 /* 521 * Disconnect the hook 522 */ 523 static int 524 ngt_disconnect(hook_p hook) 525 { 526 const sc_p sc = hook->node->private; 527 struct tty *tp = sc->tp; 528 529 lwkt_gettoken(&tp->t_token); 530 if (hook != sc->hook) 531 panic(__func__); 532 sc->hook = NULL; 533 m_freem(sc->m); 534 sc->m = NULL; 535 lwkt_reltoken(&tp->t_token); 536 537 return (0); 538 } 539 540 /* 541 * Remove this node. The does the netgraph portion of the shutdown. 542 * This should only be called indirectly from ngt_close(). 543 */ 544 static int 545 ngt_shutdown(node_p node) 546 { 547 const sc_p sc = node->private; 548 struct tty *tp = sc->tp; 549 550 if (!ngt_nodeop_ok) 551 return (EOPNOTSUPP); 552 lwkt_gettoken(&tp->t_token); 553 ng_unname(node); 554 ng_cutlinks(node); 555 node->private = NULL; 556 ng_unref(sc->node); 557 m_freem(sc->qhead); 558 m_freem(sc->m); 559 bzero(sc, sizeof(*sc)); 560 kfree(sc, M_NETGRAPH); 561 lwkt_reltoken(&tp->t_token); 562 563 return (0); 564 } 565 566 /* 567 * Receive incoming data from netgraph system. Put it on our 568 * output queue and start output if necessary. 569 */ 570 static int 571 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 572 { 573 const sc_p sc = hook->node->private; 574 struct tty *tp = sc->tp; 575 int error = 0; 576 577 if (hook != sc->hook) 578 panic(__func__); 579 NG_FREE_META(meta); 580 lwkt_gettoken(&tp->t_token); 581 if (sc->qlen >= MAX_MBUFQ) 582 ERROUT(ENOBUFS); 583 m->m_nextpkt = NULL; 584 *sc->qtail = m; 585 sc->qtail = &m->m_nextpkt; 586 sc->qlen++; 587 QUEUECHECK(sc); 588 m = NULL; 589 if (sc->qlen == 1) 590 ngt_start(sc->tp); 591 done: 592 lwkt_reltoken(&tp->t_token); 593 if (m) 594 m_freem(m); 595 return (error); 596 } 597 598 /* 599 * Receive control message 600 */ 601 static int 602 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 603 struct ng_mesg **rptr) 604 { 605 const sc_p sc = (sc_p) node->private; 606 struct tty *tp = sc->tp; 607 struct ng_mesg *resp = NULL; 608 int error = 0; 609 610 lwkt_gettoken(&tp->t_token); 611 switch (msg->header.typecookie) { 612 case NGM_TTY_COOKIE: 613 switch (msg->header.cmd) { 614 case NGM_TTY_SET_HOTCHAR: 615 { 616 int hotchar; 617 618 if (msg->header.arglen != sizeof(int)) 619 ERROUT(EINVAL); 620 hotchar = *((int *) msg->data); 621 if (hotchar != (u_char) hotchar && hotchar != -1) 622 ERROUT(EINVAL); 623 sc->hotchar = hotchar; /* race condition is OK */ 624 break; 625 } 626 case NGM_TTY_GET_HOTCHAR: 627 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 628 if (!resp) 629 ERROUT(ENOMEM); 630 /* Race condition here is OK */ 631 *((int *) resp->data) = sc->hotchar; 632 break; 633 default: 634 ERROUT(EINVAL); 635 } 636 break; 637 default: 638 ERROUT(EINVAL); 639 } 640 if (rptr) 641 *rptr = resp; 642 else if (resp) 643 kfree(resp, M_NETGRAPH); 644 645 done: 646 kfree(msg, M_NETGRAPH); 647 lwkt_reltoken(&tp->t_token); 648 649 return (error); 650 } 651 652 /****************************************************************** 653 INITIALIZATION 654 ******************************************************************/ 655 656 /* 657 * Handle loading and unloading for this node type 658 */ 659 static int 660 ngt_mod_event(module_t mod, int event, void *data) 661 { 662 /* struct ng_type *const type = data;*/ 663 int error = 0; 664 665 switch (event) { 666 case MOD_LOAD: 667 /* Register line discipline */ 668 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 669 log(LOG_ERR, "%s: can't register line discipline", 670 __func__); 671 return (EIO); 672 } 673 break; 674 675 case MOD_UNLOAD: 676 677 /* Unregister line discipline */ 678 ldisc_deregister(ngt_ldisc); 679 break; 680 681 default: 682 error = EOPNOTSUPP; 683 break; 684 } 685 return (error); 686 } 687