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 76 #include <netgraph/ng_message.h> 77 #include <netgraph/netgraph.h> 78 #include "ng_tty.h" 79 80 /* Misc defs */ 81 #define MAX_MBUFQ 3 /* Max number of queued mbufs */ 82 #define NGT_HIWATER 400 /* High water mark on output */ 83 84 /* Per-node private info */ 85 struct ngt_sc { 86 struct tty *tp; /* Terminal device */ 87 node_p node; /* Netgraph node */ 88 hook_p hook; /* Netgraph hook */ 89 struct mbuf *m; /* Incoming data buffer */ 90 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */ 91 short qlen; /* Length of queue */ 92 short hotchar; /* Hotchar, or -1 if none */ 93 u_int flags; /* Flags */ 94 struct callout ctimeout; /* See man timeout(9) */ 95 }; 96 typedef struct ngt_sc *sc_p; 97 98 /* Flags */ 99 #define FLG_TIMEOUT 0x0001 /* A timeout is pending */ 100 #define FLG_DEBUG 0x0002 101 102 /* Debugging */ 103 #ifdef INVARIANTS 104 #define QUEUECHECK(sc) \ 105 do { \ 106 struct mbuf **mp; \ 107 int k; \ 108 \ 109 for (k = 0, mp = &sc->qhead; \ 110 k <= MAX_MBUFQ && *mp; \ 111 k++, mp = &(*mp)->m_nextpkt); \ 112 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \ 113 panic("%s: queue", __func__); \ 114 } while (0) 115 #else 116 #define QUEUECHECK(sc) do {} while (0) 117 #endif 118 119 /* Line discipline methods */ 120 static int ngt_open(cdev_t dev, struct tty *tp); 121 static int ngt_close(struct tty *tp, int flag); 122 static int ngt_read(struct tty *tp, struct uio *uio, int flag); 123 static int ngt_write(struct tty *tp, struct uio *uio, int flag); 124 static int ngt_tioctl(struct tty *tp, 125 u_long cmd, caddr_t data, int flag, struct ucred *cred); 126 static int ngt_input(int c, struct tty *tp); 127 static int ngt_start(struct tty *tp); 128 129 /* Netgraph methods */ 130 static ng_constructor_t ngt_constructor; 131 static ng_rcvmsg_t ngt_rcvmsg; 132 static ng_shutdown_t ngt_shutdown; 133 static ng_newhook_t ngt_newhook; 134 static ng_rcvdata_t ngt_rcvdata; 135 static ng_disconnect_t ngt_disconnect; 136 static int ngt_mod_event(module_t mod, int event, void *data); 137 138 /* Other stuff */ 139 static void ngt_timeout(void *arg); 140 141 #define ERROUT(x) do { error = (x); goto done; } while (0) 142 143 /* Line discipline descriptor */ 144 static struct linesw ngt_disc = { 145 ngt_open, 146 ngt_close, 147 ngt_read, 148 ngt_write, 149 ngt_tioctl, 150 ngt_input, 151 ngt_start, 152 ttymodem, 153 NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */ 154 }; 155 156 /* Netgraph node type descriptor */ 157 static struct ng_type typestruct = { 158 NG_VERSION, 159 NG_TTY_NODE_TYPE, 160 ngt_mod_event, 161 ngt_constructor, 162 ngt_rcvmsg, 163 ngt_shutdown, 164 ngt_newhook, 165 NULL, 166 NULL, 167 ngt_rcvdata, 168 ngt_rcvdata, 169 ngt_disconnect, 170 NULL 171 }; 172 NETGRAPH_INIT(tty, &typestruct); 173 174 static int ngt_unit; 175 static int ngt_nodeop_ok; /* OK to create/remove node */ 176 static int ngt_ldisc; 177 178 /****************************************************************** 179 LINE DISCIPLINE METHODS 180 ******************************************************************/ 181 182 /* 183 * Set our line discipline on the tty. 184 * Called from device open routine or ttioctl() at >= splsofttty() 185 */ 186 static int 187 ngt_open(cdev_t dev, struct tty *tp) 188 { 189 struct thread *td = curthread; /* XXX */ 190 char name[sizeof(NG_TTY_NODE_TYPE) + 8]; 191 sc_p sc; 192 int error; 193 194 /* Super-user only */ 195 if ((error = priv_check(td, PRIV_ROOT))) 196 return (error); 197 lwkt_gettoken(&tp->t_token); 198 199 /* Already installed? */ 200 if (tp->t_line == NETGRAPHDISC) { 201 sc = (sc_p) tp->t_sc; 202 if (sc != NULL && sc->tp == tp) 203 goto done; 204 } 205 206 /* Initialize private struct */ 207 sc = kmalloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO); 208 sc->tp = tp; 209 sc->hotchar = NG_TTY_DFL_HOTCHAR; 210 sc->qtail = &sc->qhead; 211 QUEUECHECK(sc); 212 callout_init_mp(&sc->ctimeout); 213 214 /* Setup netgraph node */ 215 ngt_nodeop_ok = 1; 216 error = ng_make_node_common(&typestruct, &sc->node); 217 ngt_nodeop_ok = 0; 218 if (error) { 219 kfree(sc, M_NETGRAPH); 220 goto done; 221 } 222 ksnprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++); 223 224 /* Set back pointers */ 225 sc->node->private = sc; 226 tp->t_sc = (caddr_t) sc; 227 228 /* Assign node its name */ 229 if ((error = ng_name_node(sc->node, name))) { 230 log(LOG_ERR, "%s: node name exists?\n", name); 231 ngt_nodeop_ok = 1; 232 ng_rmnode(sc->node); 233 ngt_nodeop_ok = 0; 234 goto done; 235 } 236 237 /* 238 * Pre-allocate cblocks to the an appropriate amount. 239 * I'm not sure what is appropriate. 240 */ 241 ttyflush(tp, FREAD | FWRITE); 242 clist_alloc_cblocks(&tp->t_canq, 0); 243 clist_alloc_cblocks(&tp->t_rawq, 0); 244 clist_alloc_cblocks(&tp->t_outq, MLEN + NGT_HIWATER); 245 246 done: 247 /* Done */ 248 lwkt_reltoken(&tp->t_token); 249 return (error); 250 } 251 252 /* 253 * Line specific close routine, called from device close routine 254 * and from ttioctl at >= splsofttty(). This causes the node to 255 * be destroyed as well. 256 */ 257 static int 258 ngt_close(struct tty *tp, int flag) 259 { 260 const sc_p sc = (sc_p) tp->t_sc; 261 262 lwkt_gettoken(&tp->t_token); 263 ttyflush(tp, FREAD | FWRITE); 264 clist_free_cblocks(&tp->t_outq); 265 tp->t_line = 0; 266 if (sc != NULL) { 267 if (sc->flags & FLG_TIMEOUT) { 268 callout_stop(&sc->ctimeout); 269 sc->flags &= ~FLG_TIMEOUT; 270 } 271 ngt_nodeop_ok = 1; 272 ng_rmnode(sc->node); 273 ngt_nodeop_ok = 0; 274 tp->t_sc = NULL; 275 } 276 lwkt_reltoken(&tp->t_token); 277 278 return (0); 279 } 280 281 /* 282 * Once the device has been turned into a node, we don't allow reading. 283 */ 284 static int 285 ngt_read(struct tty *tp, struct uio *uio, int flag) 286 { 287 return (EIO); 288 } 289 290 /* 291 * Once the device has been turned into a node, we don't allow writing. 292 */ 293 static int 294 ngt_write(struct tty *tp, struct uio *uio, int flag) 295 { 296 return (EIO); 297 } 298 299 /* 300 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 301 */ 302 static int 303 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred) 304 { 305 const sc_p sc = (sc_p) tp->t_sc; 306 int error = 0; 307 308 lwkt_gettoken(&tp->t_token); 309 310 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 lwkt_reltoken(&tp->t_token); 329 330 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 ? sc->node : NULL; 343 struct mbuf *m; 344 int error = 0; 345 346 lwkt_gettoken(&tp->t_token); 347 if (!sc || tp != sc->tp) { 348 lwkt_reltoken(&tp->t_token); 349 return (0); 350 } 351 if (!sc->hook) 352 ERROUT(0); 353 354 /* Check for error conditions */ 355 if ((tp->t_state & TS_CONNECTED) == 0) { 356 if (sc->flags & FLG_DEBUG) 357 log(LOG_DEBUG, "%s: no carrier\n", node->name); 358 ERROUT(0); 359 } 360 if (c & TTY_ERRORMASK) { 361 /* framing error or overrun on this char */ 362 if (sc->flags & FLG_DEBUG) 363 log(LOG_DEBUG, "%s: line error %x\n", 364 node->name, c & TTY_ERRORMASK); 365 ERROUT(0); 366 } 367 c &= TTY_CHARMASK; 368 369 /* Get a new header mbuf if we need one */ 370 if (!(m = sc->m)) { 371 MGETHDR(m, M_NOWAIT, MT_DATA); 372 if (!m) { 373 if (sc->flags & FLG_DEBUG) 374 log(LOG_ERR, 375 "%s: can't get mbuf\n", node->name); 376 ERROUT(ENOBUFS); 377 } 378 m->m_len = m->m_pkthdr.len = 0; 379 m->m_pkthdr.rcvif = NULL; 380 sc->m = m; 381 } 382 383 /* Add char to mbuf */ 384 *mtod(m, u_char *) = c; 385 m->m_data++; 386 m->m_len++; 387 m->m_pkthdr.len++; 388 389 /* Ship off mbuf if it's time */ 390 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 391 m->m_data = m->m_pktdat; 392 error = ng_queue_data(sc->hook, m, NULL); 393 sc->m = NULL; 394 } 395 done: 396 lwkt_reltoken(&tp->t_token); 397 398 return (error); 399 } 400 401 /* 402 * This is called when the device driver is ready for more output. 403 * Called from tty system at splsofttty() or spltty(). 404 * Also call from ngt_rcv_data() when a new mbuf is available for output. 405 */ 406 static int 407 ngt_start(struct tty *tp) 408 { 409 const sc_p sc = (sc_p) tp->t_sc; 410 411 lwkt_gettoken(&tp->t_token); 412 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 413 struct mbuf *m = sc->qhead; 414 415 /* Remove first mbuf from queue */ 416 if (!m) 417 break; 418 if ((sc->qhead = m->m_nextpkt) == NULL) 419 sc->qtail = &sc->qhead; 420 sc->qlen--; 421 QUEUECHECK(sc); 422 423 /* Send as much of it as possible */ 424 while (m) { 425 int sent; 426 427 sent = m->m_len - clist_btoq(mtod(m, u_char *), 428 m->m_len, &tp->t_outq); 429 m->m_data += sent; 430 m->m_len -= sent; 431 if (m->m_len > 0) 432 break; /* device can't take no more */ 433 m = m_free(m); 434 } 435 436 /* Put remainder of mbuf chain (if any) back on queue */ 437 if (m) { 438 m->m_nextpkt = sc->qhead; 439 sc->qhead = m; 440 if (sc->qtail == &sc->qhead) 441 sc->qtail = &m->m_nextpkt; 442 sc->qlen++; 443 QUEUECHECK(sc); 444 break; 445 } 446 } 447 448 /* Call output process whether or not there is any output. We are 449 * being called in lieu of ttstart and must do what it would. */ 450 if (tp->t_oproc != NULL) 451 (*tp->t_oproc) (tp); 452 453 /* This timeout is needed for operation on a pseudo-tty, because the 454 * pty code doesn't call pppstart after it has drained the t_outq. */ 455 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 456 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc); 457 sc->flags |= FLG_TIMEOUT; 458 } 459 lwkt_reltoken(&tp->t_token); 460 461 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 struct tty *tp = sc->tp; 472 473 lwkt_gettoken(&tp->t_token); 474 sc->flags &= ~FLG_TIMEOUT; 475 ngt_start(tp); 476 lwkt_reltoken(&tp->t_token); 477 } 478 479 /****************************************************************** 480 NETGRAPH NODE METHODS 481 ******************************************************************/ 482 483 /* 484 * Initialize a new node of this type. 485 * 486 * We only allow nodes to be created as a result of setting 487 * the line discipline on a tty, so always return an error if not. 488 */ 489 static int 490 ngt_constructor(node_p *nodep) 491 { 492 if (!ngt_nodeop_ok) 493 return (EOPNOTSUPP); 494 return (ng_make_node_common(&typestruct, nodep)); 495 } 496 497 /* 498 * Add a new hook. There can only be one. 499 */ 500 static int 501 ngt_newhook(node_p node, hook_p hook, const char *name) 502 { 503 const sc_p sc = node->private; 504 struct tty *tp = sc->tp; 505 int error = 0; 506 507 if (strcmp(name, NG_TTY_HOOK)) 508 return (EINVAL); 509 lwkt_gettoken(&tp->t_token); 510 if (sc->hook) 511 ERROUT(EISCONN); 512 sc->hook = hook; 513 done: 514 lwkt_reltoken(&tp->t_token); 515 516 return (error); 517 } 518 519 /* 520 * Disconnect the hook 521 */ 522 static int 523 ngt_disconnect(hook_p hook) 524 { 525 const sc_p sc = hook->node->private; 526 struct tty *tp = sc->tp; 527 528 lwkt_gettoken(&tp->t_token); 529 if (hook != sc->hook) 530 panic(__func__); 531 sc->hook = NULL; 532 m_freem(sc->m); 533 sc->m = NULL; 534 lwkt_reltoken(&tp->t_token); 535 536 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 struct tty *tp = sc->tp; 548 549 if (!ngt_nodeop_ok) 550 return (EOPNOTSUPP); 551 lwkt_gettoken(&tp->t_token); 552 ng_unname(node); 553 ng_cutlinks(node); 554 node->private = NULL; 555 ng_unref(sc->node); 556 m_freem(sc->qhead); 557 m_freem(sc->m); 558 bzero(sc, sizeof(*sc)); 559 kfree(sc, M_NETGRAPH); 560 lwkt_reltoken(&tp->t_token); 561 562 return (0); 563 } 564 565 /* 566 * Receive incoming data from netgraph system. Put it on our 567 * output queue and start output if necessary. 568 */ 569 static int 570 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 571 { 572 const sc_p sc = hook->node->private; 573 struct tty *tp = sc->tp; 574 int error = 0; 575 576 if (hook != sc->hook) 577 panic(__func__); 578 NG_FREE_META(meta); 579 lwkt_gettoken(&tp->t_token); 580 if (sc->qlen >= MAX_MBUFQ) 581 ERROUT(ENOBUFS); 582 m->m_nextpkt = NULL; 583 *sc->qtail = m; 584 sc->qtail = &m->m_nextpkt; 585 sc->qlen++; 586 QUEUECHECK(sc); 587 m = NULL; 588 if (sc->qlen == 1) 589 ngt_start(sc->tp); 590 done: 591 lwkt_reltoken(&tp->t_token); 592 if (m) 593 m_freem(m); 594 return (error); 595 } 596 597 /* 598 * Receive control message 599 */ 600 static int 601 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 602 struct ng_mesg **rptr) 603 { 604 const sc_p sc = (sc_p) node->private; 605 struct tty *tp = sc->tp; 606 struct ng_mesg *resp = NULL; 607 int error = 0; 608 609 lwkt_gettoken(&tp->t_token); 610 switch (msg->header.typecookie) { 611 case NGM_TTY_COOKIE: 612 switch (msg->header.cmd) { 613 case NGM_TTY_SET_HOTCHAR: 614 { 615 int hotchar; 616 617 if (msg->header.arglen != sizeof(int)) 618 ERROUT(EINVAL); 619 hotchar = *((int *) msg->data); 620 if (hotchar != (u_char) hotchar && hotchar != -1) 621 ERROUT(EINVAL); 622 sc->hotchar = hotchar; /* race condition is OK */ 623 break; 624 } 625 case NGM_TTY_GET_HOTCHAR: 626 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 627 if (!resp) 628 ERROUT(ENOMEM); 629 /* Race condition here is OK */ 630 *((int *) resp->data) = sc->hotchar; 631 break; 632 default: 633 ERROUT(EINVAL); 634 } 635 break; 636 default: 637 ERROUT(EINVAL); 638 } 639 if (rptr) 640 *rptr = resp; 641 else if (resp) 642 kfree(resp, M_NETGRAPH); 643 644 done: 645 kfree(msg, M_NETGRAPH); 646 lwkt_reltoken(&tp->t_token); 647 648 return (error); 649 } 650 651 /****************************************************************** 652 INITIALIZATION 653 ******************************************************************/ 654 655 /* 656 * Handle loading and unloading for this node type 657 */ 658 static int 659 ngt_mod_event(module_t mod, int event, void *data) 660 { 661 /* struct ng_type *const type = data;*/ 662 int error = 0; 663 664 switch (event) { 665 case MOD_LOAD: 666 /* Register line discipline */ 667 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 668 log(LOG_ERR, "%s: can't register line discipline", 669 __func__); 670 return (EIO); 671 } 672 break; 673 674 case MOD_UNLOAD: 675 676 /* Unregister line discipline */ 677 ldisc_deregister(ngt_ldisc); 678 break; 679 680 default: 681 error = EOPNOTSUPP; 682 break; 683 } 684 return (error); 685 } 686