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/caps.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 char name[sizeof(NG_TTY_NODE_TYPE) + 8]; 190 sc_p sc; 191 int error; 192 193 /* Super-user only */ 194 if ((error = caps_priv_check_self(SYSCAP_RESTRICTEDROOT))) 195 return (error); 196 lwkt_gettoken(&tp->t_token); 197 198 /* Already installed? */ 199 if (tp->t_line == NETGRAPHDISC) { 200 sc = (sc_p) tp->t_sc; 201 if (sc != NULL && sc->tp == tp) 202 goto done; 203 } 204 205 /* Initialize private struct */ 206 sc = kmalloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO); 207 sc->tp = tp; 208 sc->hotchar = NG_TTY_DFL_HOTCHAR; 209 sc->qtail = &sc->qhead; 210 QUEUECHECK(sc); 211 callout_init_mp(&sc->ctimeout); 212 213 /* Setup netgraph node */ 214 ngt_nodeop_ok = 1; 215 error = ng_make_node_common(&typestruct, &sc->node); 216 ngt_nodeop_ok = 0; 217 if (error) { 218 kfree(sc, M_NETGRAPH); 219 goto done; 220 } 221 ksnprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++); 222 223 /* Set back pointers */ 224 sc->node->private = sc; 225 tp->t_sc = (caddr_t) sc; 226 227 /* Assign node its name */ 228 if ((error = ng_name_node(sc->node, name))) { 229 log(LOG_ERR, "%s: node name exists?\n", name); 230 ngt_nodeop_ok = 1; 231 ng_rmnode(sc->node); 232 ngt_nodeop_ok = 0; 233 goto done; 234 } 235 236 /* 237 * Pre-allocate cblocks to the an appropriate amount. 238 * I'm not sure what is appropriate. 239 */ 240 ttyflush(tp, FREAD | FWRITE); 241 clist_alloc_cblocks(&tp->t_canq, 0); 242 clist_alloc_cblocks(&tp->t_rawq, 0); 243 clist_alloc_cblocks(&tp->t_outq, MLEN + NGT_HIWATER); 244 245 done: 246 /* Done */ 247 lwkt_reltoken(&tp->t_token); 248 return (error); 249 } 250 251 /* 252 * Line specific close routine, called from device close routine 253 * and from ttioctl at >= splsofttty(). This causes the node to 254 * be destroyed as well. 255 */ 256 static int 257 ngt_close(struct tty *tp, int flag) 258 { 259 const sc_p sc = (sc_p) tp->t_sc; 260 261 lwkt_gettoken(&tp->t_token); 262 ttyflush(tp, FREAD | FWRITE); 263 clist_free_cblocks(&tp->t_outq); 264 tp->t_line = 0; 265 if (sc != NULL) { 266 if (sc->flags & FLG_TIMEOUT) { 267 callout_stop(&sc->ctimeout); 268 sc->flags &= ~FLG_TIMEOUT; 269 } 270 ngt_nodeop_ok = 1; 271 ng_rmnode(sc->node); 272 ngt_nodeop_ok = 0; 273 tp->t_sc = NULL; 274 } 275 lwkt_reltoken(&tp->t_token); 276 277 return (0); 278 } 279 280 /* 281 * Once the device has been turned into a node, we don't allow reading. 282 */ 283 static int 284 ngt_read(struct tty *tp, struct uio *uio, int flag) 285 { 286 return (EIO); 287 } 288 289 /* 290 * Once the device has been turned into a node, we don't allow writing. 291 */ 292 static int 293 ngt_write(struct tty *tp, struct uio *uio, int flag) 294 { 295 return (EIO); 296 } 297 298 /* 299 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 300 */ 301 static int 302 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred) 303 { 304 const sc_p sc = (sc_p) tp->t_sc; 305 int error = 0; 306 307 lwkt_gettoken(&tp->t_token); 308 309 switch (cmd) { 310 case NGIOCGINFO: 311 { 312 struct nodeinfo *const ni = (struct nodeinfo *) data; 313 const node_p node = sc->node; 314 315 bzero(ni, sizeof(*ni)); 316 if (node->name) 317 strncpy(ni->name, node->name, sizeof(ni->name) - 1); 318 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1); 319 ni->id = (u_int32_t)(uintptr_t)node; 320 ni->hooks = node->numhooks; 321 break; 322 } 323 default: 324 ERROUT(ENOIOCTL); 325 } 326 done: 327 lwkt_reltoken(&tp->t_token); 328 329 return (error); 330 } 331 332 /* 333 * Receive data coming from the device. We get one character at 334 * a time, which is kindof silly. 335 * Only guaranteed to be at splsofttty() or spltty(). 336 */ 337 static int 338 ngt_input(int c, struct tty *tp) 339 { 340 const sc_p sc = (sc_p) tp->t_sc; 341 const node_p node = sc ? sc->node : NULL; 342 struct mbuf *m; 343 int error = 0; 344 345 lwkt_gettoken(&tp->t_token); 346 if (!sc || tp != sc->tp) { 347 lwkt_reltoken(&tp->t_token); 348 return (0); 349 } 350 if (!sc->hook) 351 ERROUT(0); 352 353 /* Check for error conditions */ 354 if ((tp->t_state & TS_CONNECTED) == 0) { 355 if (sc->flags & FLG_DEBUG) 356 log(LOG_DEBUG, "%s: no carrier\n", node->name); 357 ERROUT(0); 358 } 359 if (c & TTY_ERRORMASK) { 360 /* framing error or overrun on this char */ 361 if (sc->flags & FLG_DEBUG) 362 log(LOG_DEBUG, "%s: line error %x\n", 363 node->name, c & TTY_ERRORMASK); 364 ERROUT(0); 365 } 366 c &= TTY_CHARMASK; 367 368 /* Get a new header mbuf if we need one */ 369 if (!(m = sc->m)) { 370 MGETHDR(m, M_NOWAIT, MT_DATA); 371 if (!m) { 372 if (sc->flags & FLG_DEBUG) 373 log(LOG_ERR, 374 "%s: can't get mbuf\n", node->name); 375 ERROUT(ENOBUFS); 376 } 377 m->m_len = m->m_pkthdr.len = 0; 378 m->m_pkthdr.rcvif = NULL; 379 sc->m = m; 380 } 381 382 /* Add char to mbuf */ 383 *mtod(m, u_char *) = c; 384 m->m_data++; 385 m->m_len++; 386 m->m_pkthdr.len++; 387 388 /* Ship off mbuf if it's time */ 389 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 390 m->m_data = m->m_pktdat; 391 error = ng_queue_data(sc->hook, m, NULL); 392 sc->m = NULL; 393 } 394 done: 395 lwkt_reltoken(&tp->t_token); 396 397 return (error); 398 } 399 400 /* 401 * This is called when the device driver is ready for more output. 402 * Called from tty system at splsofttty() or spltty(). 403 * Also call from ngt_rcv_data() when a new mbuf is available for output. 404 */ 405 static int 406 ngt_start(struct tty *tp) 407 { 408 const sc_p sc = (sc_p) tp->t_sc; 409 410 lwkt_gettoken(&tp->t_token); 411 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 412 struct mbuf *m = sc->qhead; 413 414 /* Remove first mbuf from queue */ 415 if (!m) 416 break; 417 if ((sc->qhead = m->m_nextpkt) == NULL) 418 sc->qtail = &sc->qhead; 419 sc->qlen--; 420 QUEUECHECK(sc); 421 422 /* Send as much of it as possible */ 423 while (m) { 424 int sent; 425 426 sent = m->m_len - clist_btoq(mtod(m, u_char *), 427 m->m_len, &tp->t_outq); 428 m->m_data += sent; 429 m->m_len -= sent; 430 if (m->m_len > 0) 431 break; /* device can't take no more */ 432 m = m_free(m); 433 } 434 435 /* Put remainder of mbuf chain (if any) back on queue */ 436 if (m) { 437 m->m_nextpkt = sc->qhead; 438 sc->qhead = m; 439 if (sc->qtail == &sc->qhead) 440 sc->qtail = &m->m_nextpkt; 441 sc->qlen++; 442 QUEUECHECK(sc); 443 break; 444 } 445 } 446 447 /* Call output process whether or not there is any output. We are 448 * being called in lieu of ttstart and must do what it would. */ 449 if (tp->t_oproc != NULL) 450 (*tp->t_oproc) (tp); 451 452 /* This timeout is needed for operation on a pseudo-tty, because the 453 * pty code doesn't call pppstart after it has drained the t_outq. */ 454 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 455 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc); 456 sc->flags |= FLG_TIMEOUT; 457 } 458 lwkt_reltoken(&tp->t_token); 459 460 return (0); 461 } 462 463 /* 464 * We still have data to output to the device, so try sending more. 465 */ 466 static void 467 ngt_timeout(void *arg) 468 { 469 const sc_p sc = (sc_p) arg; 470 struct tty *tp = sc->tp; 471 472 lwkt_gettoken(&tp->t_token); 473 sc->flags &= ~FLG_TIMEOUT; 474 ngt_start(tp); 475 lwkt_reltoken(&tp->t_token); 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 struct tty *tp = sc->tp; 504 int error = 0; 505 506 if (strcmp(name, NG_TTY_HOOK)) 507 return (EINVAL); 508 lwkt_gettoken(&tp->t_token); 509 if (sc->hook) 510 ERROUT(EISCONN); 511 sc->hook = hook; 512 done: 513 lwkt_reltoken(&tp->t_token); 514 515 return (error); 516 } 517 518 /* 519 * Disconnect the hook 520 */ 521 static int 522 ngt_disconnect(hook_p hook) 523 { 524 const sc_p sc = hook->node->private; 525 struct tty *tp = sc->tp; 526 527 lwkt_gettoken(&tp->t_token); 528 if (hook != sc->hook) 529 panic(__func__); 530 sc->hook = NULL; 531 m_freem(sc->m); 532 sc->m = NULL; 533 lwkt_reltoken(&tp->t_token); 534 535 return (0); 536 } 537 538 /* 539 * Remove this node. The does the netgraph portion of the shutdown. 540 * This should only be called indirectly from ngt_close(). 541 */ 542 static int 543 ngt_shutdown(node_p node) 544 { 545 const sc_p sc = node->private; 546 struct tty *tp = sc->tp; 547 548 if (!ngt_nodeop_ok) 549 return (EOPNOTSUPP); 550 lwkt_gettoken(&tp->t_token); 551 ng_unname(node); 552 ng_cutlinks(node); 553 node->private = NULL; 554 ng_unref(sc->node); 555 m_freem(sc->qhead); 556 m_freem(sc->m); 557 bzero(sc, sizeof(*sc)); 558 kfree(sc, M_NETGRAPH); 559 lwkt_reltoken(&tp->t_token); 560 561 return (0); 562 } 563 564 /* 565 * Receive incoming data from netgraph system. Put it on our 566 * output queue and start output if necessary. 567 */ 568 static int 569 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 570 { 571 const sc_p sc = hook->node->private; 572 struct tty *tp = sc->tp; 573 int error = 0; 574 575 if (hook != sc->hook) 576 panic(__func__); 577 NG_FREE_META(meta); 578 lwkt_gettoken(&tp->t_token); 579 if (sc->qlen >= MAX_MBUFQ) 580 ERROUT(ENOBUFS); 581 m->m_nextpkt = NULL; 582 *sc->qtail = m; 583 sc->qtail = &m->m_nextpkt; 584 sc->qlen++; 585 QUEUECHECK(sc); 586 m = NULL; 587 if (sc->qlen == 1) 588 ngt_start(sc->tp); 589 done: 590 lwkt_reltoken(&tp->t_token); 591 if (m) 592 m_freem(m); 593 return (error); 594 } 595 596 /* 597 * Receive control message 598 */ 599 static int 600 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 601 struct ng_mesg **rptr) 602 { 603 const sc_p sc = (sc_p) node->private; 604 struct tty *tp = sc->tp; 605 struct ng_mesg *resp = NULL; 606 int error = 0; 607 608 lwkt_gettoken(&tp->t_token); 609 switch (msg->header.typecookie) { 610 case NGM_TTY_COOKIE: 611 switch (msg->header.cmd) { 612 case NGM_TTY_SET_HOTCHAR: 613 { 614 int hotchar; 615 616 if (msg->header.arglen != sizeof(int)) 617 ERROUT(EINVAL); 618 hotchar = *((int *) msg->data); 619 if (hotchar != (u_char) hotchar && hotchar != -1) 620 ERROUT(EINVAL); 621 sc->hotchar = hotchar; /* race condition is OK */ 622 break; 623 } 624 case NGM_TTY_GET_HOTCHAR: 625 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 626 if (!resp) 627 ERROUT(ENOMEM); 628 /* Race condition here is OK */ 629 *((int *) resp->data) = sc->hotchar; 630 break; 631 default: 632 ERROUT(EINVAL); 633 } 634 break; 635 default: 636 ERROUT(EINVAL); 637 } 638 if (rptr) 639 *rptr = resp; 640 else if (resp) 641 kfree(resp, M_NETGRAPH); 642 643 done: 644 kfree(msg, M_NETGRAPH); 645 lwkt_reltoken(&tp->t_token); 646 647 return (error); 648 } 649 650 /****************************************************************** 651 INITIALIZATION 652 ******************************************************************/ 653 654 /* 655 * Handle loading and unloading for this node type 656 */ 657 static int 658 ngt_mod_event(module_t mod, int event, void *data) 659 { 660 /* struct ng_type *const type = data;*/ 661 int error = 0; 662 663 switch (event) { 664 case MOD_LOAD: 665 /* Register line discipline */ 666 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 667 log(LOG_ERR, "%s: can't register line discipline", 668 __func__); 669 return (EIO); 670 } 671 break; 672 673 case MOD_UNLOAD: 674 675 /* Unregister line discipline */ 676 ldisc_deregister(ngt_ldisc); 677 break; 678 679 default: 680 error = EOPNOTSUPP; 681 break; 682 } 683 return (error); 684 } 685