ng_tty.c revision 52442
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 52442 1999-10-23 04:52:54Z 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/ttycom.h> 73#include <sys/syslog.h> 74#include <sys/errno.h> 75#include <sys/ioccom.h> 76 77#include <netgraph/ng_message.h> 78#include <netgraph/netgraph.h> 79#include <netgraph/ng_tty.h> 80 81#ifdef __i386__ /* fiddle with the spl locking */ 82#include <machine/ipl.h> 83#include <i386/isa/intr_machdep.h> 84#endif 85 86/* Misc defs */ 87#define MAX_MBUFQ 3 /* Max number of queued mbufs */ 88#define NGT_HIWATER 400 /* High water mark on output */ 89 90/* Per-node private info */ 91struct ngt_sc { 92 struct tty *tp; /* Terminal device */ 93 node_p node; /* Netgraph node */ 94 hook_p hook; /* Netgraph hook */ 95 struct mbuf *m; /* Incoming data buffer */ 96 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */ 97 short qlen; /* Length of queue */ 98 short hotchar; /* Hotchar, or -1 if none */ 99 u_int flags; /* Flags */ 100 struct callout_handle chand; /* See man timeout(9) */ 101}; 102typedef struct ngt_sc *sc_p; 103 104/* Flags */ 105#define FLG_TIMEOUT 0x0001 /* A timeout is pending */ 106#define FLG_DEBUG 0x0002 107 108/* Debugging */ 109#ifdef DIAGNOSTICS 110#define QUEUECHECK(sc) \ 111 do { \ 112 struct mbuf **mp; \ 113 int k; \ 114 \ 115 for (k = 0, mp = &sc->qhead; \ 116 k <= MAX_MBUFQ && *mp; \ 117 k++, mp = &(*mp)->m_nextpkt); \ 118 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \ 119 panic(__FUNCTION__ ": queue"); \ 120 } while (0) 121#else 122#define QUEUECHECK(sc) do {} while (0) 123#endif 124 125/* Line discipline methods */ 126static int ngt_open(dev_t dev, struct tty *tp); 127static int ngt_close(struct tty *tp, int flag); 128static int ngt_read(struct tty *tp, struct uio *uio, int flag); 129static int ngt_write(struct tty *tp, struct uio *uio, int flag); 130static int ngt_tioctl(struct tty *tp, 131 u_long cmd, caddr_t data, int flag, struct proc *); 132static int ngt_input(int c, struct tty *tp); 133static int ngt_start(struct tty *tp); 134 135/* Netgraph methods */ 136static int ngt_constructor(node_p *node); 137static int ngt_rcvmsg(node_p node, struct ng_mesg *msg, 138 const char *retaddr, struct ng_mesg **resp); 139static int ngt_shutdown(node_p node); 140static int ngt_newhook(node_p node, hook_p hook, const char *name); 141static int ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta); 142static int ngt_disconnect(hook_p hook); 143static int ngt_mod_event(module_t mod, int event, void *data); 144 145/* Other stuff */ 146static void ngt_timeout(void *arg); 147 148#define ERROUT(x) do { error = (x); goto done; } while (0) 149 150/* Line discipline descriptor */ 151static struct linesw ngt_disc = { 152 ngt_open, 153 ngt_close, 154 ngt_read, 155 ngt_write, 156 ngt_tioctl, 157 ngt_input, 158 ngt_start, 159 ttymodem, 160 NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */ 161}; 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 */ 182static int ngt_ldisc; 183 184/****************************************************************** 185 LINE DISCIPLINE METHODS 186******************************************************************/ 187 188/* 189 * Set our line discipline on the tty. 190 * Called from device open routine or ttioctl() at >= splsofttty() 191 */ 192static int 193ngt_open(dev_t dev, struct tty *tp) 194{ 195 struct proc *const p = curproc; /* XXX */ 196 char name[sizeof(NG_TTY_NODE_TYPE) + 8]; 197 sc_p sc; 198 int s, error; 199 200 /* Super-user only */ 201 if ((error = suser(p))) 202 return (error); 203 s = splnet(); 204 (void) spltty(); /* XXX is this necessary? */ 205 206 /* Already installed? */ 207 if (tp->t_line == NETGRAPHDISC) { 208 sc = (sc_p) tp->t_sc; 209 if (sc != NULL && sc->tp == tp) 210 goto done; 211 } 212 213 /* Initialize private struct */ 214 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK); 215 if (sc == NULL) { 216 error = ENOMEM; 217 goto done; 218 } 219 bzero(sc, sizeof(*sc)); 220 sc->tp = tp; 221 sc->hotchar = NG_TTY_DFL_HOTCHAR; 222 sc->qtail = &sc->qhead; 223 QUEUECHECK(sc); 224 callout_handle_init(&sc->chand); 225 226 /* Setup netgraph node */ 227 ngt_nodeop_ok = 1; 228 error = ng_make_node_common(&typestruct, &sc->node); 229 ngt_nodeop_ok = 0; 230 if (error) { 231 FREE(sc, M_NETGRAPH); 232 goto done; 233 } 234 sprintf(name, "%s%d", typestruct.name, ngt_unit++); 235 236 /* Set back pointers */ 237 sc->node->private = sc; 238 tp->t_sc = (caddr_t) sc; 239 240 /* Assign node its name */ 241 if ((error = ng_name_node(sc->node, name))) { 242 log(LOG_ERR, "%s: node name exists?\n", name); 243 ngt_nodeop_ok = 1; 244 ng_rmnode(sc->node); 245 ngt_nodeop_ok = 0; 246 goto done; 247 } 248 249 /* 250 * Pre-allocate cblocks to the an appropriate amount. 251 * I'm not sure what is appropriate. 252 */ 253 ttyflush(tp, FREAD | FWRITE); 254 clist_alloc_cblocks(&tp->t_canq, 0, 0); 255 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 256 clist_alloc_cblocks(&tp->t_outq, 257 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER); 258 259done: 260 /* Done */ 261 splx(s); 262 return (error); 263} 264 265/* 266 * Line specific close routine, called from device close routine 267 * and from ttioctl at >= splsofttty(). This causes the node to 268 * be destroyed as well. 269 */ 270static int 271ngt_close(struct tty *tp, int flag) 272{ 273 const sc_p sc = (sc_p) tp->t_sc; 274 int s; 275 276 s = spltty(); 277 ttyflush(tp, FREAD | FWRITE); 278 clist_free_cblocks(&tp->t_outq); 279 tp->t_line = 0; 280 if (sc != NULL) { 281 if (sc->flags & FLG_TIMEOUT) { 282 untimeout(ngt_timeout, sc, sc->chand); 283 sc->flags &= ~FLG_TIMEOUT; 284 } 285 ngt_nodeop_ok = 1; 286 ng_rmnode(sc->node); 287 ngt_nodeop_ok = 0; 288 tp->t_sc = NULL; 289 } 290 splx(s); 291 return (0); 292} 293 294/* 295 * Once the device has been turned into a node, we don't allow reading. 296 */ 297static int 298ngt_read(struct tty *tp, struct uio *uio, int flag) 299{ 300 return (EIO); 301} 302 303/* 304 * Once the device has been turned into a node, we don't allow writing. 305 */ 306static int 307ngt_write(struct tty *tp, struct uio *uio, int flag) 308{ 309 return (EIO); 310} 311 312/* 313 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 314 */ 315static int 316ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct proc *p) 317{ 318 const sc_p sc = (sc_p) tp->t_sc; 319 int s, error = 0; 320 321 s = spltty(); 322 switch (cmd) { 323 case NGIOCGINFO: 324 { 325 struct nodeinfo *const ni = (struct nodeinfo *) data; 326 const node_p node = sc->node; 327 328 bzero(ni, sizeof(*ni)); 329 if (node->name) 330 strncpy(ni->name, node->name, sizeof(ni->name) - 1); 331 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1); 332 ni->id = (u_int32_t) node; 333 ni->hooks = node->numhooks; 334 break; 335 } 336 default: 337 ERROUT(ENOIOCTL); 338 } 339done: 340 splx(s); 341 return (error); 342} 343 344/* 345 * Receive data coming from the device. We get one character at 346 * a time, which is kindof silly. 347 * Only guaranteed to be at splsofttty() or spltty(). 348 */ 349static int 350ngt_input(int c, struct tty *tp) 351{ 352 const sc_p sc = (sc_p) tp->t_sc; 353 const node_p node = sc->node; 354 struct mbuf *m; 355 int s, error = 0; 356 357 if (!sc || tp != sc->tp) 358 return (0); 359 s = spltty(); 360 if (!sc->hook) 361 ERROUT(0); 362 363 /* Check for error conditions */ 364 if ((tp->t_state & TS_CONNECTED) == 0) { 365 if (sc->flags & FLG_DEBUG) 366 log(LOG_DEBUG, "%s: no carrier\n", node->name); 367 ERROUT(0); 368 } 369 if (c & TTY_ERRORMASK) { 370 /* framing error or overrun on this char */ 371 if (sc->flags & FLG_DEBUG) 372 log(LOG_DEBUG, "%s: line error %x\n", 373 node->name, c & TTY_ERRORMASK); 374 ERROUT(0); 375 } 376 c &= TTY_CHARMASK; 377 378 /* Get a new header mbuf if we need one */ 379 if (!(m = sc->m)) { 380 MGETHDR(m, M_DONTWAIT, MT_DATA); 381 if (!m) { 382 if (sc->flags & FLG_DEBUG) 383 log(LOG_ERR, 384 "%s: can't get mbuf\n", node->name); 385 ERROUT(ENOBUFS); 386 } 387 m->m_len = 0; 388 m->m_pkthdr.len = 0; 389 sc->m = m; 390 } 391 392 /* Add char to mbuf */ 393 *mtod(m, u_char *) = c; 394 m->m_data++; 395 m->m_len++; 396 m->m_pkthdr.len++; 397 398 /* Ship off mbuf if it's time */ 399 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 400 m->m_data = m->m_pktdat; 401 error = ng_queue_data(sc->hook, m, NULL); 402 sc->m = NULL; 403 } 404done: 405 splx(s); 406 return (error); 407} 408 409/* 410 * This is called when the device driver is ready for more output. 411 * Called from tty system at splsofttty() or spltty(). 412 * Also call from ngt_rcv_data() when a new mbuf is available for output. 413 */ 414static int 415ngt_start(struct tty *tp) 416{ 417 const sc_p sc = (sc_p) tp->t_sc; 418 int s; 419 420 s = spltty(); 421 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */ 422 struct mbuf *m = sc->qhead; 423 424 /* Remove first mbuf from queue */ 425 if (!m) 426 break; 427 if ((sc->qhead = m->m_nextpkt) == NULL) 428 sc->qtail = &sc->qhead; 429 sc->qlen--; 430 QUEUECHECK(sc); 431 432 /* Send as much of it as possible */ 433 while (m) { 434 struct mbuf *m2; 435 int sent; 436 437 sent = m->m_len 438 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq); 439 m->m_data += sent; 440 m->m_len -= sent; 441 if (m->m_len > 0) 442 break; /* device can't take no more */ 443 MFREE(m, m2); 444 m = m2; 445 } 446 447 /* Put remainder of mbuf chain (if any) back on queue */ 448 if (m) { 449 m->m_nextpkt = sc->qhead; 450 sc->qhead = m; 451 if (sc->qtail == &sc->qhead) 452 sc->qtail = &m->m_nextpkt; 453 sc->qlen++; 454 QUEUECHECK(sc); 455 break; 456 } 457 } 458 459 /* Call output process whether or not there is any output. We are 460 * being called in lieu of ttstart and must do what it would. */ 461 if (tp->t_oproc != NULL) 462 (*tp->t_oproc) (tp); 463 464 /* This timeout is needed for operation on a pseudo-tty, because the 465 * pty code doesn't call pppstart after it has drained the t_outq. */ 466 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) { 467 sc->chand = timeout(ngt_timeout, sc, 1); 468 sc->flags |= FLG_TIMEOUT; 469 } 470 splx(s); 471 return (0); 472} 473 474/* 475 * We still have data to output to the device, so try sending more. 476 */ 477static void 478ngt_timeout(void *arg) 479{ 480 const sc_p sc = (sc_p) arg; 481 int s; 482 483 s = spltty(); 484 sc->flags &= ~FLG_TIMEOUT; 485 ngt_start(sc->tp); 486 splx(s); 487} 488 489/****************************************************************** 490 NETGRAPH NODE METHODS 491******************************************************************/ 492 493/* 494 * Initialize a new node of this type. 495 * 496 * We only allow nodes to be created as a result of setting 497 * the line discipline on a tty, so always return an error if not. 498 */ 499static int 500ngt_constructor(node_p *nodep) 501{ 502 if (!ngt_nodeop_ok) 503 return (EOPNOTSUPP); 504 return (ng_make_node_common(&typestruct, nodep)); 505} 506 507/* 508 * Add a new hook. There can only be one. 509 */ 510static int 511ngt_newhook(node_p node, hook_p hook, const char *name) 512{ 513 const sc_p sc = node->private; 514 int s, error = 0; 515 516 if (strcmp(name, NG_TTY_HOOK)) 517 return (EINVAL); 518 s = spltty(); 519 if (sc->hook) 520 ERROUT(EISCONN); 521 sc->hook = hook; 522done: 523 splx(s); 524 return (error); 525} 526 527/* 528 * Disconnect the hook 529 */ 530static int 531ngt_disconnect(hook_p hook) 532{ 533 const sc_p sc = hook->node->private; 534 int s; 535 536 s = spltty(); 537 if (hook != sc->hook) 538 panic(__FUNCTION__); 539 sc->hook = NULL; 540 m_freem(sc->m); 541 sc->m = NULL; 542 splx(s); 543 return (0); 544} 545 546/* 547 * Remove this node. The does the netgraph portion of the shutdown. 548 * This should only be called indirectly from ngt_close(). 549 */ 550static int 551ngt_shutdown(node_p node) 552{ 553 const sc_p sc = node->private; 554 555 if (!ngt_nodeop_ok) 556 return (EOPNOTSUPP); 557 ng_unname(node); 558 ng_cutlinks(node); 559 node->private = NULL; 560 ng_unref(sc->node); 561 m_freem(sc->qhead); 562 m_freem(sc->m); 563 bzero(sc, sizeof(*sc)); 564 FREE(sc, M_NETGRAPH); 565 return (0); 566} 567 568/* 569 * Receive incoming data from netgraph system. Put it on our 570 * output queue and start output if necessary. 571 */ 572static int 573ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 574{ 575 const sc_p sc = hook->node->private; 576 int s, error = 0; 577 578 if (hook != sc->hook) 579 panic(__FUNCTION__); 580 NG_FREE_META(meta); 581 s = spltty(); 582 if (sc->qlen >= MAX_MBUFQ) 583 ERROUT(ENOBUFS); 584 m->m_nextpkt = NULL; 585 *sc->qtail = m; 586 sc->qtail = &m->m_nextpkt; 587 sc->qlen++; 588 QUEUECHECK(sc); 589 m = NULL; 590 if (sc->qlen == 1) 591 ngt_start(sc->tp); 592done: 593 splx(s); 594 if (m) 595 m_freem(m); 596 return (error); 597} 598 599/* 600 * Receive control message 601 */ 602static int 603ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 604 struct ng_mesg **rptr) 605{ 606 const sc_p sc = (sc_p) node->private; 607 struct ng_mesg *resp = NULL; 608 int error = 0; 609 610 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 FREE(resp, M_NETGRAPH); 643 644done: 645 FREE(msg, M_NETGRAPH); 646 return (error); 647} 648 649/****************************************************************** 650 INITIALIZATION 651******************************************************************/ 652 653/* 654 * Handle loading and unloading for this node type 655 */ 656static int 657ngt_mod_event(module_t mod, int event, void *data) 658{ 659 /* struct ng_type *const type = data;*/ 660 int s, error = 0; 661 662 switch (event) { 663 case MOD_LOAD: 664#ifdef __i386__ 665 /* Insure the soft net "engine" can't run during spltty code */ 666 s = splhigh(); 667 tty_imask |= softnet_imask; /* spltty() block spl[soft]net() */ 668 net_imask |= softtty_imask; /* splimp() block splsofttty() */ 669 net_imask |= tty_imask; /* splimp() block spltty() */ 670 update_intr_masks(); 671 splx(s); 672 673 if (bootverbose) 674 log(LOG_DEBUG, "new masks: bio %x, tty %x, net %x\n", 675 bio_imask, tty_imask, net_imask); 676#endif 677 678 /* Register line discipline */ 679 s = spltty(); 680 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 681 splx(s); 682 log(LOG_ERR, "%s: can't register line discipline", 683 __FUNCTION__); 684 return (EIO); 685 } 686 splx(s); 687 break; 688 689 case MOD_UNLOAD: 690 691 /* Unregister line discipline */ 692 s = spltty(); 693 ldisc_deregister(ngt_ldisc); 694 splx(s); 695 break; 696 697 default: 698 error = EOPNOTSUPP; 699 break; 700 } 701 return (error); 702} 703 704