ng_tty.c revision 52419
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 52419 1999-10-21 09:06:11Z julian $ 40 * $Whistle: ng_tty.c,v 1.18 1999/01/28 23:54:54 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/socket.h> 69#include <sys/fcntl.h> 70#include <sys/file.h> 71#include <sys/tty.h> 72#include <sys/syslog.h> 73#include <sys/errno.h> 74#include <sys/ioccom.h> 75 76#include <netgraph/ng_message.h> 77#include <netgraph/netgraph.h> 78#include <netgraph/ng_tty.h> 79 80#ifdef __i386__ /* fiddle with the spl locking */ 81#include <machine/ipl.h> 82#include <i386/isa/intr_machdep.h> 83#endif 84 85/* Misc defs */ 86#define MAX_MBUFQ 3 /* Max number of queued mbufs */ 87#define NGT_HIWATER 400 /* High water mark on output */ 88 89/* Per-node private info */ 90struct ngt_sc { 91 struct tty *tp; /* Terminal device */ 92 node_p node; /* Netgraph node */ 93 hook_p hook; /* Netgraph hook */ 94 struct mbuf *m; /* Incoming data buffer */ 95 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */ 96 short qlen; /* Length of queue */ 97 short hotchar; /* Hotchar, or -1 if none */ 98 u_int flags; /* Flags */ 99 struct callout_handle chand; /* See man timeout(9) */ 100}; 101typedef struct ngt_sc *sc_p; 102 103/* Flags */ 104#define FLG_TIMEOUT 0x0001 /* A timeout is pending */ 105#define FLG_DEBUG 0x0002 106 107/* Debugging */ 108#ifdef DIAGNOSTICS 109#define QUEUECHECK(sc) \ 110 do { \ 111 struct mbuf **mp; \ 112 int k; \ 113 \ 114 for (k = 0, mp = &sc->qhead; \ 115 k <= MAX_MBUFQ && *mp; \ 116 k++, mp = &(*mp)->m_nextpkt); \ 117 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \ 118 panic(__FUNCTION__ ": queue"); \ 119 } while (0) 120#else 121#define QUEUECHECK(sc) do {} while (0) 122#endif 123 124/* Line discipline methods */ 125static int ngt_open(dev_t dev, struct tty *tp); 126static int ngt_close(struct tty *tp, int flag); 127static int ngt_read(struct tty *tp, struct uio *uio, int flag); 128static int ngt_write(struct tty *tp, struct uio *uio, int flag); 129static int ngt_tioctl(struct tty *tp, 130 u_long cmd, caddr_t data, int flag, struct proc *); 131static int ngt_input(int c, struct tty *tp); 132static int ngt_start(struct tty *tp); 133 134/* Netgraph methods */ 135static int ngt_constructor(node_p *node); 136static int ngt_rcvmsg(node_p node, struct ng_mesg *msg, 137 const char *retaddr, struct ng_mesg **resp); 138static int ngt_shutdown(node_p node); 139static int ngt_newhook(node_p node, hook_p hook, const char *name); 140static int ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta); 141static int ngt_disconnect(hook_p hook); 142static int ngt_mod_event(module_t mod, int event, void *data); 143 144/* Other stuff */ 145static void ngt_timeout(void *arg); 146 147#define ERROUT(x) do { error = (x); goto done; } while (0) 148 149/* Line discipline descriptor */ 150static 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}; 161static int ngt_ldisc = -1; 162 163/* Netgraph node type descriptor */ 164static struct ng_type typestruct = { 165 NG_VERSION, 166 NG_TTY_NODE_TYPE, 167 ngt_mod_event, 168 ngt_constructor, 169 ngt_rcvmsg, 170 ngt_shutdown, 171 ngt_newhook, 172 NULL, 173 NULL, 174 ngt_rcvdata, 175 ngt_rcvdata, 176 ngt_disconnect, 177}; 178NETGRAPH_INIT(tty, &typestruct); 179 180static int ngt_unit; 181static int ngt_nodeop_ok; /* OK to create/remove node */ 182 183/****************************************************************** 184 LINE DISCIPLINE METHODS 185******************************************************************/ 186 187/* 188 * Set our line discipline on the tty. 189 * Called from device open routine or ttioctl() at >= splsofttty() 190 */ 191static int 192ngt_open(dev_t dev, struct tty *tp) 193{ 194 struct proc *const p = curproc; /* XXX */ 195 char name[sizeof(NG_TTY_NODE_TYPE) + 8]; 196 sc_p sc; 197 int s, error; 198 199 /* Super-user only */ 200 if ((error = suser(p))) 201 return (error); 202 s = splnet(); 203 (void) spltty(); /* XXX is this necessary? */ 204 205 /* Already installed? */ 206 if (tp->t_line == ngt_ldisc) { 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_handle_init(&sc->chand); 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 sprintf(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 258done: 259 /* Done */ 260 splx(s); 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 */ 269static int 270ngt_close(struct tty *tp, int flag) 271{ 272 const sc_p sc = (sc_p) tp->t_sc; 273 int s; 274 275 s = spltty(); 276 ttyflush(tp, FREAD | FWRITE); 277 clist_free_cblocks(&tp->t_outq); 278 tp->t_line = 0; 279 if (sc != NULL) { 280 if (sc->flags & FLG_TIMEOUT) { 281 untimeout(ngt_timeout, sc, sc->chand); 282 sc->flags &= ~FLG_TIMEOUT; 283 } 284 ngt_nodeop_ok = 1; 285 ng_rmnode(sc->node); 286 ngt_nodeop_ok = 0; 287 tp->t_sc = NULL; 288 } 289 splx(s); 290 return (0); 291} 292 293/* 294 * Once the device has been turned into a node, we don't allow reading. 295 */ 296static int 297ngt_read(struct tty *tp, struct uio *uio, int flag) 298{ 299 return (EIO); 300} 301 302/* 303 * Once the device has been turned into a node, we don't allow writing. 304 */ 305static int 306ngt_write(struct tty *tp, struct uio *uio, int flag) 307{ 308 return (EIO); 309} 310 311/* 312 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 313 */ 314static int 315ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct proc *p) 316{ 317 const sc_p sc = (sc_p) tp->t_sc; 318 int s, error = 0; 319 320 s = spltty(); 321 switch (cmd) { 322 case NGIOCGINFO: 323 { 324 struct nodeinfo *const ni = (struct nodeinfo *) data; 325 const node_p node = sc->node; 326 327 bzero(ni, sizeof(*ni)); 328 if (node->name) 329 strncpy(ni->name, node->name, sizeof(ni->name) - 1); 330 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1); 331 ni->id = (u_int32_t) node; 332 ni->hooks = node->numhooks; 333 break; 334 } 335 default: 336 ERROUT(ENOIOCTL); 337 } 338done: 339 splx(s); 340 return (error); 341} 342 343/* 344 * Receive data coming from the device. We get one character at 345 * a time, which is kindof silly. 346 * Only guaranteed to be at splsofttty() or spltty(). 347 */ 348static int 349ngt_input(int c, struct tty *tp) 350{ 351 const sc_p sc = (sc_p) tp->t_sc; 352 const node_p node = sc->node; 353 struct mbuf *m; 354 int s, error = 0; 355 356 if (!sc || tp != sc->tp) 357 return (0); 358 s = spltty(); 359 if (!sc->hook) 360 ERROUT(0); 361 362 /* Check for error conditions */ 363 if ((tp->t_state & TS_CONNECTED) == 0) { 364 if (sc->flags & FLG_DEBUG) 365 log(LOG_DEBUG, "%s: no carrier\n", node->name); 366 ERROUT(0); 367 } 368 if (c & TTY_ERRORMASK) { 369 /* framing error or overrun on this char */ 370 if (sc->flags & FLG_DEBUG) 371 log(LOG_DEBUG, "%s: line error %x\n", 372 node->name, c & TTY_ERRORMASK); 373 ERROUT(0); 374 } 375 c &= TTY_CHARMASK; 376 377 /* Get a new header mbuf if we need one */ 378 if (!(m = sc->m)) { 379 MGETHDR(m, M_DONTWAIT, MT_DATA); 380 if (!m) { 381 if (sc->flags & FLG_DEBUG) 382 log(LOG_ERR, 383 "%s: can't get mbuf\n", node->name); 384 ERROUT(ENOBUFS); 385 } 386 m->m_len = 0; 387 m->m_pkthdr.len = 0; 388 sc->m = m; 389 } 390 391 /* Add char to mbuf */ 392 *mtod(m, u_char *) = c; 393 m->m_data++; 394 m->m_len++; 395 m->m_pkthdr.len++; 396 397 /* Ship off mbuf if it's time */ 398 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 399 m->m_data = m->m_pktdat; 400 error = ng_queue_data(sc->hook, m, NULL); 401 sc->m = NULL; 402 } 403done: 404 splx(s); 405 return (error); 406} 407 408/* 409 * This is called when the device driver is ready for more output. 410 * Called from tty system at splsofttty() or spltty(). 411 * Also call from ngt_rcv_data() when a new mbuf is available for output. 412 */ 413static int 414ngt_start(struct tty *tp) 415{ 416 const sc_p sc = (sc_p) tp->t_sc; 417 int s; 418 419 s = spltty(); 420 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 421 struct mbuf *m = sc->qhead; 422 423 /* Remove first mbuf from queue */ 424 if (!m) 425 break; 426 if ((sc->qhead = m->m_nextpkt) == NULL) 427 sc->qtail = &sc->qhead; 428 sc->qlen--; 429 QUEUECHECK(sc); 430 431 /* Send as much of it as possible */ 432 while (m) { 433 struct mbuf *m2; 434 int sent; 435 436 sent = m->m_len 437 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq); 438 m->m_data += sent; 439 m->m_len -= sent; 440 if (m->m_len > 0) 441 break; /* device can't take no more */ 442 MFREE(m, m2); 443 m = m2; 444 } 445 446 /* Put remainder of mbuf chain (if any) back on queue */ 447 if (m) { 448 m->m_nextpkt = sc->qhead; 449 sc->qhead = m; 450 if (sc->qtail == &sc->qhead) 451 sc->qtail = &m->m_nextpkt; 452 sc->qlen++; 453 QUEUECHECK(sc); 454 break; 455 } 456 } 457 458 /* Call output process whether or not there is any output. We are 459 * being called in lieu of ttstart and must do what it would. */ 460 if (tp->t_oproc != NULL) 461 (*tp->t_oproc) (tp); 462 463 /* This timeout is needed for operation on a pseudo-tty, because the 464 * pty code doesn't call pppstart after it has drained the t_outq. */ 465 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 466 sc->chand = timeout(ngt_timeout, sc, 1); 467 sc->flags |= FLG_TIMEOUT; 468 } 469 splx(s); 470 return (0); 471} 472 473/* 474 * We still have data to output to the device, so try sending more. 475 */ 476static void 477ngt_timeout(void *arg) 478{ 479 const sc_p sc = (sc_p) arg; 480 int s; 481 482 s = spltty(); 483 sc->flags &= ~FLG_TIMEOUT; 484 ngt_start(sc->tp); 485 splx(s); 486} 487 488/****************************************************************** 489 NETGRAPH NODE METHODS 490******************************************************************/ 491 492/* 493 * Initialize a new node of this type. 494 * 495 * We only allow nodes to be created as a result of setting 496 * the line discipline on a tty, so always return an error if not. 497 */ 498static int 499ngt_constructor(node_p *nodep) 500{ 501 if (!ngt_nodeop_ok) 502 return (EOPNOTSUPP); 503 return (ng_make_node_common(&typestruct, nodep)); 504} 505 506/* 507 * Add a new hook. There can only be one. 508 */ 509static int 510ngt_newhook(node_p node, hook_p hook, const char *name) 511{ 512 const sc_p sc = node->private; 513 int s, error = 0; 514 515 if (strcmp(name, NG_TTY_HOOK)) 516 return (EINVAL); 517 s = spltty(); 518 if (sc->hook) 519 ERROUT(EISCONN); 520 sc->hook = hook; 521done: 522 splx(s); 523 return (error); 524} 525 526/* 527 * Disconnect the hook 528 */ 529static int 530ngt_disconnect(hook_p hook) 531{ 532 const sc_p sc = hook->node->private; 533 int s; 534 535 s = spltty(); 536 if (hook != sc->hook) 537 panic(__FUNCTION__); 538 sc->hook = NULL; 539 m_freem(sc->m); 540 sc->m = NULL; 541 splx(s); 542 return (0); 543} 544 545/* 546 * Remove this node. The does the netgraph portion of the shutdown. 547 * This should only be called indirectly from ngt_close(). 548 */ 549static int 550ngt_shutdown(node_p node) 551{ 552 const sc_p sc = node->private; 553 554 if (!ngt_nodeop_ok) 555 return (EOPNOTSUPP); 556 ng_unname(node); 557 ng_cutlinks(node); 558 node->private = NULL; 559 ng_unref(sc->node); 560 m_freem(sc->qhead); 561 m_freem(sc->m); 562 bzero(sc, sizeof(*sc)); 563 FREE(sc, M_NETGRAPH); 564 return (0); 565} 566 567/* 568 * Receive incoming data from netgraph system. Put it on our 569 * output queue and start output if necessary. 570 */ 571static int 572ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 573{ 574 const sc_p sc = hook->node->private; 575 int s, error = 0; 576 577 if (hook != sc->hook) 578 panic(__FUNCTION__); 579 NG_FREE_META(meta); 580 s = spltty(); 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); 591done: 592 splx(s); 593 if (m) 594 m_freem(m); 595 return (error); 596} 597 598/* 599 * Receive control message 600 */ 601static int 602ngt_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 ng_mesg *resp = NULL; 607 int error = 0; 608 609 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 FREE(resp, M_NETGRAPH); 642 643done: 644 FREE(msg, M_NETGRAPH); 645 return (error); 646} 647 648/****************************************************************** 649 INITIALIZATION 650******************************************************************/ 651 652/* 653 * Handle loading and unloading for this node type 654 */ 655static int 656ngt_mod_event(module_t mod, int event, void *data) 657{ 658 struct ng_type *const type = data; 659 int s, error = 0; 660 661 switch (event) { 662 case MOD_LOAD: 663#ifdef __i386__ 664 /* Insure the soft net "engine" can't run during spltty code */ 665 s = splhigh(); 666 tty_imask |= softnet_imask; /* spltty() block spl[soft]net() */ 667 net_imask |= softtty_imask; /* splimp() block splsofttty() */ 668 net_imask |= tty_imask; /* splimp() block spltty() */ 669 update_intr_masks(); 670 splx(s); 671 672 if (bootverbose) 673 log(LOG_DEBUG, "new masks: bio %x, tty %x, net %x\n", 674 bio_imask, tty_imask, net_imask); 675#endif 676 677 /* Register line discipline */ 678 s = spltty(); 679 if ((ngt_ldisc = ldisc_register(LDISC_LOAD, &ngt_disc)) < 0) { 680 splx(s); 681 log(LOG_ERR, "%s: can't register line discipline", 682 __FUNCTION__); 683 return (EIO); 684 } 685 splx(s); 686 687 /* OK */ 688 log(LOG_INFO, "line discipline #%d registered to" 689 " netgraph node type \"%s\"\n", ngt_ldisc, type->name); 690 break; 691 692 case MOD_UNLOAD: 693 694 /* Unregister line discipline */ 695 s = spltty(); 696 ldisc_deregister(ngt_ldisc); 697 splx(s); 698 break; 699 700 default: 701 error = EOPNOTSUPP; 702 break; 703 } 704 return (error); 705} 706 707