ng_tty.c revision 58012
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@whistle.com> 38 * 39 * $FreeBSD: head/sys/netgraph/ng_tty.c 58012 2000-03-13 18:54:10Z archie $ 40 * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $ 41 */ 42 43/* 44 * This file implements a terminal line discipline that is also a 45 * netgraph node. Installing this line discipline on a terminal device 46 * instantiates a new netgraph node of this type, which allows access 47 * to the device via the "hook" hook of the node. 48 * 49 * Once the line discipline is installed, you can find out the name 50 * of the corresponding netgraph node via a NGIOCGINFO ioctl(). 51 * 52 * Incoming characters are delievered to the hook one at a time, each 53 * in its own mbuf. You may optionally define a ``hotchar,'' which causes 54 * incoming characters to be buffered up until either the hotchar is 55 * seen or the mbuf is full (MHLEN bytes). Then all buffered characters 56 * are immediately delivered. 57 * 58 * NOTE: This node operates at spltty(). 59 */ 60 61#include <sys/param.h> 62#include <sys/systm.h> 63#include <sys/kernel.h> 64#include <sys/conf.h> 65#include <sys/proc.h> 66#include <sys/mbuf.h> 67#include <sys/malloc.h> 68#include <sys/fcntl.h> 69#include <sys/tty.h> 70#include <sys/ttycom.h> 71#include <sys/syslog.h> 72#include <sys/errno.h> 73#include <sys/ioccom.h> 74 75#include <netgraph/ng_message.h> 76#include <netgraph/netgraph.h> 77#include <netgraph/ng_tty.h> 78 79#ifdef __i386__ /* fiddle with the spl locking */ 80#include <machine/ipl.h> 81#include <i386/isa/intr_machdep.h> 82#endif 83 84/* Misc defs */ 85#define MAX_MBUFQ 3 /* Max number of queued mbufs */ 86#define NGT_HIWATER 400 /* High water mark on output */ 87 88/* Per-node private info */ 89struct ngt_sc { 90 struct tty *tp; /* Terminal device */ 91 node_p node; /* Netgraph node */ 92 hook_p hook; /* Netgraph hook */ 93 struct mbuf *m; /* Incoming data buffer */ 94 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */ 95 short qlen; /* Length of queue */ 96 short hotchar; /* Hotchar, or -1 if none */ 97 u_int flags; /* Flags */ 98 struct callout_handle chand; /* See man timeout(9) */ 99}; 100typedef struct ngt_sc *sc_p; 101 102/* Flags */ 103#define FLG_TIMEOUT 0x0001 /* A timeout is pending */ 104#define FLG_DEBUG 0x0002 105 106/* Debugging */ 107#ifdef INVARIANTS 108#define QUEUECHECK(sc) \ 109 do { \ 110 struct mbuf **mp; \ 111 int k; \ 112 \ 113 for (k = 0, mp = &sc->qhead; \ 114 k <= MAX_MBUFQ && *mp; \ 115 k++, mp = &(*mp)->m_nextpkt); \ 116 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \ 117 panic(__FUNCTION__ ": queue"); \ 118 } while (0) 119#else 120#define QUEUECHECK(sc) do {} while (0) 121#endif 122 123/* Line discipline methods */ 124static int ngt_open(dev_t dev, struct tty *tp); 125static int ngt_close(struct tty *tp, int flag); 126static int ngt_read(struct tty *tp, struct uio *uio, int flag); 127static int ngt_write(struct tty *tp, struct uio *uio, int flag); 128static int ngt_tioctl(struct tty *tp, 129 u_long cmd, caddr_t data, int flag, struct proc *); 130static int ngt_input(int c, struct tty *tp); 131static int ngt_start(struct tty *tp); 132 133/* Netgraph methods */ 134static ng_constructor_t ngt_constructor; 135static ng_rcvmsg_t ngt_rcvmsg; 136static ng_shutdown_t ngt_shutdown; 137static ng_newhook_t ngt_newhook; 138static ng_rcvdata_t ngt_rcvdata; 139static ng_disconnect_t ngt_disconnect; 140static int ngt_mod_event(module_t mod, int event, void *data); 141 142/* Other stuff */ 143static void ngt_timeout(void *arg); 144 145#define ERROUT(x) do { error = (x); goto done; } while (0) 146 147/* Line discipline descriptor */ 148static struct linesw ngt_disc = { 149 ngt_open, 150 ngt_close, 151 ngt_read, 152 ngt_write, 153 ngt_tioctl, 154 ngt_input, 155 ngt_start, 156 ttymodem, 157 NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */ 158}; 159 160/* Netgraph node type descriptor */ 161static struct ng_type typestruct = { 162 NG_VERSION, 163 NG_TTY_NODE_TYPE, 164 ngt_mod_event, 165 ngt_constructor, 166 ngt_rcvmsg, 167 ngt_shutdown, 168 ngt_newhook, 169 NULL, 170 NULL, 171 ngt_rcvdata, 172 ngt_rcvdata, 173 ngt_disconnect, 174 NULL 175}; 176NETGRAPH_INIT(tty, &typestruct); 177 178static int ngt_unit; 179static int ngt_nodeop_ok; /* OK to create/remove node */ 180static int ngt_ldisc; 181 182/****************************************************************** 183 LINE DISCIPLINE METHODS 184******************************************************************/ 185 186/* 187 * Set our line discipline on the tty. 188 * Called from device open routine or ttioctl() at >= splsofttty() 189 */ 190static int 191ngt_open(dev_t dev, struct tty *tp) 192{ 193 struct proc *const p = curproc; /* XXX */ 194 char name[sizeof(NG_TTY_NODE_TYPE) + 8]; 195 sc_p sc; 196 int s, error; 197 198 /* Super-user only */ 199 if ((error = suser(p))) 200 return (error); 201 s = splnet(); 202 (void) spltty(); /* XXX is this necessary? */ 203 204 /* Already installed? */ 205 if (tp->t_line == NETGRAPHDISC) { 206 sc = (sc_p) tp->t_sc; 207 if (sc != NULL && sc->tp == tp) 208 goto done; 209 } 210 211 /* Initialize private struct */ 212 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK); 213 if (sc == NULL) { 214 error = ENOMEM; 215 goto done; 216 } 217 bzero(sc, sizeof(*sc)); 218 sc->tp = tp; 219 sc->hotchar = NG_TTY_DFL_HOTCHAR; 220 sc->qtail = &sc->qhead; 221 QUEUECHECK(sc); 222 callout_handle_init(&sc->chand); 223 224 /* Setup netgraph node */ 225 ngt_nodeop_ok = 1; 226 error = ng_make_node_common(&typestruct, &sc->node); 227 ngt_nodeop_ok = 0; 228 if (error) { 229 FREE(sc, M_NETGRAPH); 230 goto done; 231 } 232 snprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++); 233 234 /* Set back pointers */ 235 sc->node->private = sc; 236 tp->t_sc = (caddr_t) sc; 237 238 /* Assign node its name */ 239 if ((error = ng_name_node(sc->node, name))) { 240 log(LOG_ERR, "%s: node name exists?\n", name); 241 ngt_nodeop_ok = 1; 242 ng_rmnode(sc->node); 243 ngt_nodeop_ok = 0; 244 goto done; 245 } 246 247 /* 248 * Pre-allocate cblocks to the an appropriate amount. 249 * I'm not sure what is appropriate. 250 */ 251 ttyflush(tp, FREAD | FWRITE); 252 clist_alloc_cblocks(&tp->t_canq, 0, 0); 253 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 254 clist_alloc_cblocks(&tp->t_outq, 255 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER); 256 257done: 258 /* Done */ 259 splx(s); 260 return (error); 261} 262 263/* 264 * Line specific close routine, called from device close routine 265 * and from ttioctl at >= splsofttty(). This causes the node to 266 * be destroyed as well. 267 */ 268static int 269ngt_close(struct tty *tp, int flag) 270{ 271 const sc_p sc = (sc_p) tp->t_sc; 272 int s; 273 274 s = spltty(); 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 untimeout(ngt_timeout, sc, sc->chand); 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 splx(s); 289 return (0); 290} 291 292/* 293 * Once the device has been turned into a node, we don't allow reading. 294 */ 295static int 296ngt_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 */ 304static int 305ngt_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 */ 313static int 314ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct proc *p) 315{ 316 const sc_p sc = (sc_p) tp->t_sc; 317 int s, error = 0; 318 319 s = spltty(); 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 } 337done: 338 splx(s); 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 */ 347static int 348ngt_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 s, error = 0; 354 355 if (!sc || tp != sc->tp) 356 return (0); 357 s = spltty(); 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, M_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 } 402done: 403 splx(s); 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 */ 412static int 413ngt_start(struct tty *tp) 414{ 415 const sc_p sc = (sc_p) tp->t_sc; 416 int s; 417 418 s = spltty(); 419 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 420 struct mbuf *m = sc->qhead; 421 422 /* Remove first mbuf from queue */ 423 if (!m) 424 break; 425 if ((sc->qhead = m->m_nextpkt) == NULL) 426 sc->qtail = &sc->qhead; 427 sc->qlen--; 428 QUEUECHECK(sc); 429 430 /* Send as much of it as possible */ 431 while (m) { 432 struct mbuf *m2; 433 int sent; 434 435 sent = m->m_len 436 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq); 437 m->m_data += sent; 438 m->m_len -= sent; 439 if (m->m_len > 0) 440 break; /* device can't take no more */ 441 MFREE(m, m2); 442 m = m2; 443 } 444 445 /* Put remainder of mbuf chain (if any) back on queue */ 446 if (m) { 447 m->m_nextpkt = sc->qhead; 448 sc->qhead = m; 449 if (sc->qtail == &sc->qhead) 450 sc->qtail = &m->m_nextpkt; 451 sc->qlen++; 452 QUEUECHECK(sc); 453 break; 454 } 455 } 456 457 /* Call output process whether or not there is any output. We are 458 * being called in lieu of ttstart and must do what it would. */ 459 if (tp->t_oproc != NULL) 460 (*tp->t_oproc) (tp); 461 462 /* This timeout is needed for operation on a pseudo-tty, because the 463 * pty code doesn't call pppstart after it has drained the t_outq. */ 464 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 465 sc->chand = timeout(ngt_timeout, sc, 1); 466 sc->flags |= FLG_TIMEOUT; 467 } 468 splx(s); 469 return (0); 470} 471 472/* 473 * We still have data to output to the device, so try sending more. 474 */ 475static void 476ngt_timeout(void *arg) 477{ 478 const sc_p sc = (sc_p) arg; 479 int s; 480 481 s = spltty(); 482 sc->flags &= ~FLG_TIMEOUT; 483 ngt_start(sc->tp); 484 splx(s); 485} 486 487/****************************************************************** 488 NETGRAPH NODE METHODS 489******************************************************************/ 490 491/* 492 * Initialize a new node of this type. 493 * 494 * We only allow nodes to be created as a result of setting 495 * the line discipline on a tty, so always return an error if not. 496 */ 497static int 498ngt_constructor(node_p *nodep) 499{ 500 if (!ngt_nodeop_ok) 501 return (EOPNOTSUPP); 502 return (ng_make_node_common(&typestruct, nodep)); 503} 504 505/* 506 * Add a new hook. There can only be one. 507 */ 508static int 509ngt_newhook(node_p node, hook_p hook, const char *name) 510{ 511 const sc_p sc = node->private; 512 int s, error = 0; 513 514 if (strcmp(name, NG_TTY_HOOK)) 515 return (EINVAL); 516 s = spltty(); 517 if (sc->hook) 518 ERROUT(EISCONN); 519 sc->hook = hook; 520done: 521 splx(s); 522 return (error); 523} 524 525/* 526 * Disconnect the hook 527 */ 528static int 529ngt_disconnect(hook_p hook) 530{ 531 const sc_p sc = hook->node->private; 532 int s; 533 534 s = spltty(); 535 if (hook != sc->hook) 536 panic(__FUNCTION__); 537 sc->hook = NULL; 538 m_freem(sc->m); 539 sc->m = NULL; 540 splx(s); 541 return (0); 542} 543 544/* 545 * Remove this node. The does the netgraph portion of the shutdown. 546 * This should only be called indirectly from ngt_close(). 547 */ 548static int 549ngt_shutdown(node_p node) 550{ 551 const sc_p sc = node->private; 552 553 if (!ngt_nodeop_ok) 554 return (EOPNOTSUPP); 555 ng_unname(node); 556 ng_cutlinks(node); 557 node->private = NULL; 558 ng_unref(sc->node); 559 m_freem(sc->qhead); 560 m_freem(sc->m); 561 bzero(sc, sizeof(*sc)); 562 FREE(sc, M_NETGRAPH); 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 */ 570static int 571ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 572{ 573 const sc_p sc = hook->node->private; 574 int s, error = 0; 575 576 if (hook != sc->hook) 577 panic(__FUNCTION__); 578 NG_FREE_META(meta); 579 s = spltty(); 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); 590done: 591 splx(s); 592 if (m) 593 m_freem(m); 594 return (error); 595} 596 597/* 598 * Receive control message 599 */ 600static int 601ngt_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 ng_mesg *resp = NULL; 606 int error = 0; 607 608 switch (msg->header.typecookie) { 609 case NGM_TTY_COOKIE: 610 switch (msg->header.cmd) { 611 case NGM_TTY_SET_HOTCHAR: 612 { 613 int hotchar; 614 615 if (msg->header.arglen != sizeof(int)) 616 ERROUT(EINVAL); 617 hotchar = *((int *) msg->data); 618 if (hotchar != (u_char) hotchar && hotchar != -1) 619 ERROUT(EINVAL); 620 sc->hotchar = hotchar; /* race condition is OK */ 621 break; 622 } 623 case NGM_TTY_GET_HOTCHAR: 624 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 625 if (!resp) 626 ERROUT(ENOMEM); 627 /* Race condition here is OK */ 628 *((int *) resp->data) = sc->hotchar; 629 break; 630 default: 631 ERROUT(EINVAL); 632 } 633 break; 634 default: 635 ERROUT(EINVAL); 636 } 637 if (rptr) 638 *rptr = resp; 639 else if (resp) 640 FREE(resp, M_NETGRAPH); 641 642done: 643 FREE(msg, M_NETGRAPH); 644 return (error); 645} 646 647/****************************************************************** 648 INITIALIZATION 649******************************************************************/ 650 651/* 652 * Handle loading and unloading for this node type 653 */ 654static int 655ngt_mod_event(module_t mod, int event, void *data) 656{ 657 /* struct ng_type *const type = data;*/ 658 int s, error = 0; 659 660 switch (event) { 661 case MOD_LOAD: 662#ifdef __i386__ 663 /* Insure the soft net "engine" can't run during spltty code */ 664 s = splhigh(); 665 tty_imask |= softnet_imask; /* spltty() block spl[soft]net() */ 666 net_imask |= softtty_imask; /* splimp() block splsofttty() */ 667 net_imask |= tty_imask; /* splimp() block spltty() */ 668 update_intr_masks(); 669 splx(s); 670 671 if (bootverbose) 672 log(LOG_DEBUG, "new masks: bio %x, tty %x, net %x\n", 673 bio_imask, tty_imask, net_imask); 674#endif 675 676 /* Register line discipline */ 677 s = spltty(); 678 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 679 splx(s); 680 log(LOG_ERR, "%s: can't register line discipline", 681 __FUNCTION__); 682 return (EIO); 683 } 684 splx(s); 685 break; 686 687 case MOD_UNLOAD: 688 689 /* Unregister line discipline */ 690 s = spltty(); 691 ldisc_deregister(ngt_ldisc); 692 splx(s); 693 break; 694 695 default: 696 error = EOPNOTSUPP; 697 break; 698 } 699 return (error); 700} 701 702