ng_tty.c revision 111119
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@freebsd.org> 38 * 39 * $FreeBSD: head/sys/netgraph/ng_tty.c 111119 2003-02-19 05:47:46Z imp $ 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/mbuf.h> 66#include <sys/malloc.h> 67#include <sys/fcntl.h> 68#include <sys/tty.h> 69#include <sys/ttycom.h> 70#include <sys/syslog.h> 71#include <sys/errno.h> 72#include <sys/ioccom.h> 73 74#include <netgraph/ng_message.h> 75#include <netgraph/netgraph.h> 76#include <netgraph/ng_tty.h> 77 78/* Misc defs */ 79#define MAX_MBUFQ 3 /* Max number of queued mbufs */ 80#define NGT_HIWATER 400 /* High water mark on output */ 81 82/* Per-node private info */ 83struct ngt_sc { 84 struct tty *tp; /* Terminal device */ 85 node_p node; /* Netgraph node */ 86 hook_p hook; /* Netgraph hook */ 87 struct mbuf *m; /* Incoming data buffer */ 88 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */ 89 short qlen; /* Length of queue */ 90 short hotchar; /* Hotchar, or -1 if none */ 91 u_int flags; /* Flags */ 92 struct callout_handle chand; /* See man timeout(9) */ 93}; 94typedef struct ngt_sc *sc_p; 95 96/* Flags */ 97#define FLG_TIMEOUT 0x0001 /* A timeout is pending */ 98#define FLG_DEBUG 0x0002 99 100/* Debugging */ 101#ifdef INVARIANTS 102#define QUEUECHECK(sc) \ 103 do { \ 104 struct mbuf **mp; \ 105 int k; \ 106 \ 107 for (k = 0, mp = &sc->qhead; \ 108 k <= MAX_MBUFQ && *mp; \ 109 k++, mp = &(*mp)->m_nextpkt); \ 110 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \ 111 panic("%s: queue", __func__); \ 112 } while (0) 113#else 114#define QUEUECHECK(sc) do {} while (0) 115#endif 116 117/* Line discipline methods */ 118static int ngt_open(dev_t dev, struct tty *tp); 119static int ngt_close(struct tty *tp, int flag); 120static int ngt_read(struct tty *tp, struct uio *uio, int flag); 121static int ngt_write(struct tty *tp, struct uio *uio, int flag); 122static int ngt_tioctl(struct tty *tp, 123 u_long cmd, caddr_t data, int flag, struct thread *); 124static int ngt_input(int c, struct tty *tp); 125static int ngt_start(struct tty *tp); 126 127/* Netgraph methods */ 128static ng_constructor_t ngt_constructor; 129static ng_rcvmsg_t ngt_rcvmsg; 130static ng_shutdown_t ngt_shutdown; 131static ng_newhook_t ngt_newhook; 132static ng_connect_t ngt_connect; 133static ng_rcvdata_t ngt_rcvdata; 134static ng_disconnect_t ngt_disconnect; 135static int ngt_mod_event(module_t mod, int event, void *data); 136 137/* Other stuff */ 138static void ngt_timeout(void *arg); 139 140#define ERROUT(x) do { error = (x); goto done; } while (0) 141 142/* Line discipline descriptor */ 143static struct linesw ngt_disc = { 144 ngt_open, 145 ngt_close, 146 ngt_read, 147 ngt_write, 148 ngt_tioctl, 149 ngt_input, 150 ngt_start, 151 ttymodem, 152 NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */ 153}; 154 155/* Netgraph node type descriptor */ 156static struct ng_type typestruct = { 157 NG_ABI_VERSION, 158 NG_TTY_NODE_TYPE, 159 ngt_mod_event, 160 ngt_constructor, 161 ngt_rcvmsg, 162 ngt_shutdown, 163 ngt_newhook, 164 NULL, 165 ngt_connect, 166 ngt_rcvdata, 167 ngt_disconnect, 168 NULL 169}; 170NETGRAPH_INIT(tty, &typestruct); 171 172static int ngt_unit; 173static int ngt_nodeop_ok; /* OK to create/remove node */ 174static int ngt_ldisc; 175 176/****************************************************************** 177 LINE DISCIPLINE METHODS 178******************************************************************/ 179 180/* 181 * Set our line discipline on the tty. 182 * Called from device open routine or ttioctl() at >= splsofttty() 183 */ 184static int 185ngt_open(dev_t dev, struct tty *tp) 186{ 187 struct thread *const td = curthread; /* XXX */ 188 char name[sizeof(NG_TTY_NODE_TYPE) + 8]; 189 sc_p sc; 190 int s, error; 191 192 /* Super-user only */ 193 if ((error = suser(td))) 194 return (error); 195 s = splnet(); 196 (void) spltty(); /* XXX is this necessary? */ 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 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO); 207 if (sc == NULL) { 208 error = ENOMEM; 209 goto done; 210 } 211 sc->tp = tp; 212 sc->hotchar = NG_TTY_DFL_HOTCHAR; 213 sc->qtail = &sc->qhead; 214 QUEUECHECK(sc); 215 callout_handle_init(&sc->chand); 216 217 /* Setup netgraph node */ 218 ngt_nodeop_ok = 1; 219 error = ng_make_node_common(&typestruct, &sc->node); 220 ngt_nodeop_ok = 0; 221 if (error) { 222 FREE(sc, M_NETGRAPH); 223 goto done; 224 } 225 snprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++); 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_NODE_UNREF(sc->node); 232 ngt_nodeop_ok = 0; 233 goto done; 234 } 235 236 /* Set back pointers */ 237 NG_NODE_SET_PRIVATE(sc->node, sc); 238 tp->t_sc = (caddr_t) sc; 239 240 /* 241 * Pre-allocate cblocks to the an appropriate amount. 242 * I'm not sure what is appropriate. 243 */ 244 ttyflush(tp, FREAD | FWRITE); 245 clist_alloc_cblocks(&tp->t_canq, 0, 0); 246 clist_alloc_cblocks(&tp->t_rawq, 0, 0); 247 clist_alloc_cblocks(&tp->t_outq, 248 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER); 249 250done: 251 /* Done */ 252 splx(s); 253 return (error); 254} 255 256/* 257 * Line specific close routine, called from device close routine 258 * and from ttioctl at >= splsofttty(). This causes the node to 259 * be destroyed as well. 260 */ 261static int 262ngt_close(struct tty *tp, int flag) 263{ 264 const sc_p sc = (sc_p) tp->t_sc; 265 int s; 266 267 s = spltty(); 268 ttyflush(tp, FREAD | FWRITE); 269 clist_free_cblocks(&tp->t_outq); 270 tp->t_line = 0; 271 if (sc != NULL) { 272 if (sc->flags & FLG_TIMEOUT) { 273 untimeout(ngt_timeout, sc, sc->chand); 274 sc->flags &= ~FLG_TIMEOUT; 275 } 276 ngt_nodeop_ok = 1; 277 ng_rmnode_self(sc->node); 278 ngt_nodeop_ok = 0; 279 tp->t_sc = NULL; 280 } 281 splx(s); 282 return (0); 283} 284 285/* 286 * Once the device has been turned into a node, we don't allow reading. 287 */ 288static int 289ngt_read(struct tty *tp, struct uio *uio, int flag) 290{ 291 return (EIO); 292} 293 294/* 295 * Once the device has been turned into a node, we don't allow writing. 296 */ 297static int 298ngt_write(struct tty *tp, struct uio *uio, int flag) 299{ 300 return (EIO); 301} 302 303/* 304 * We implement the NGIOCGINFO ioctl() defined in ng_message.h. 305 */ 306static int 307ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct thread *td) 308{ 309 const sc_p sc = (sc_p) tp->t_sc; 310 int s, error = 0; 311 312 s = spltty(); 313 switch (cmd) { 314 case NGIOCGINFO: 315 { 316 struct nodeinfo *const ni = (struct nodeinfo *) data; 317 const node_p node = sc->node; 318 319 bzero(ni, sizeof(*ni)); 320 if (NG_NODE_HAS_NAME(node)) 321 strncpy(ni->name, NG_NODE_NAME(node), sizeof(ni->name) - 1); 322 strncpy(ni->type, node->nd_type->name, sizeof(ni->type) - 1); 323 ni->id = (u_int32_t) ng_node2ID(node); 324 ni->hooks = NG_NODE_NUMHOOKS(node); 325 break; 326 } 327 default: 328 ERROUT(ENOIOCTL); 329 } 330done: 331 splx(s); 332 return (error); 333} 334 335/* 336 * Receive data coming from the device. We get one character at 337 * a time, which is kindof silly. 338 * Only guaranteed to be at splsofttty() or spltty(). 339 */ 340static int 341ngt_input(int c, struct tty *tp) 342{ 343 const sc_p sc = (sc_p) tp->t_sc; 344 const node_p node = sc->node; 345 struct mbuf *m; 346 int s, error = 0; 347 348 if (!sc || tp != sc->tp) 349 return (0); 350 s = spltty(); 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", NG_NODE_NAME(node)); 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 NG_NODE_NAME(node), 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_DONTWAIT, MT_DATA); 372 if (!m) { 373 if (sc->flags & FLG_DEBUG) 374 log(LOG_ERR, 375 "%s: can't get mbuf\n", NG_NODE_NAME(node)); 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 NG_SEND_DATA_ONLY(error, sc->hook, m); 393 sc->m = NULL; 394 } 395done: 396 splx(s); 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 */ 405static int 406ngt_start(struct tty *tp) 407{ 408 const sc_p sc = (sc_p) tp->t_sc; 409 int s; 410 411 s = spltty(); 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 428 - b_to_q(mtod(m, u_char *), 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 sc->chand = timeout(ngt_timeout, sc, 1); 457 sc->flags |= FLG_TIMEOUT; 458 } 459 splx(s); 460 return (0); 461} 462 463/* 464 * We still have data to output to the device, so try sending more. 465 */ 466static void 467ngt_timeout(void *arg) 468{ 469 const sc_p sc = (sc_p) arg; 470 int s; 471 472 s = spltty(); 473 sc->flags &= ~FLG_TIMEOUT; 474 ngt_start(sc->tp); 475 splx(s); 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 */ 488static int 489ngt_constructor(node_p node) 490{ 491 return (EOPNOTSUPP); 492} 493 494/* 495 * Add a new hook. There can only be one. 496 */ 497static int 498ngt_newhook(node_p node, hook_p hook, const char *name) 499{ 500 const sc_p sc = NG_NODE_PRIVATE(node); 501 int s, error = 0; 502 503 if (strcmp(name, NG_TTY_HOOK)) 504 return (EINVAL); 505 s = spltty(); 506 if (sc->hook) 507 ERROUT(EISCONN); 508 sc->hook = hook; 509done: 510 splx(s); 511 return (error); 512} 513 514/* 515 * Set the hooks into queueing mode (for outgoing packets) 516 * Force single client at a time. 517 */ 518static int 519ngt_connect(hook_p hook) 520{ 521 /*NG_HOOK_FORCE_WRITER(hook); 522 NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));*/ 523 return (0); 524} 525 526/* 527 * Disconnect the hook 528 */ 529static int 530ngt_disconnect(hook_p hook) 531{ 532 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 533 int s; 534 535 s = spltty(); 536 if (hook != sc->hook) 537 panic(__func__); 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 = NG_NODE_PRIVATE(node); 553 554 if (!ngt_nodeop_ok) 555 return (EOPNOTSUPP); 556 NG_NODE_SET_PRIVATE(node, NULL); 557 NG_NODE_UNREF(sc->node); 558 m_freem(sc->qhead); 559 m_freem(sc->m); 560 bzero(sc, sizeof(*sc)); 561 FREE(sc, M_NETGRAPH); 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 */ 569static int 570ngt_rcvdata(hook_p hook, item_p item) 571{ 572 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 573 int s, error = 0; 574 struct mbuf *m; 575 576 if (hook != sc->hook) 577 panic(__func__); 578 579 NGI_GET_M(item, m); 580 NG_FREE_ITEM(item); 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, item_p item, hook_p lasthook) 604{ 605 const sc_p sc = NG_NODE_PRIVATE(node); 606 struct ng_mesg *resp = NULL; 607 int error = 0; 608 struct ng_mesg *msg; 609 610 NGI_GET_MSG(item, msg); 611 switch (msg->header.typecookie) { 612 case NGM_TTY_COOKIE: 613 switch (msg->header.cmd) { 614 case NGM_TTY_SET_HOTCHAR: 615 { 616 int hotchar; 617 618 if (msg->header.arglen != sizeof(int)) 619 ERROUT(EINVAL); 620 hotchar = *((int *) msg->data); 621 if (hotchar != (u_char) hotchar && hotchar != -1) 622 ERROUT(EINVAL); 623 sc->hotchar = hotchar; /* race condition is OK */ 624 break; 625 } 626 case NGM_TTY_GET_HOTCHAR: 627 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 628 if (!resp) 629 ERROUT(ENOMEM); 630 /* Race condition here is OK */ 631 *((int *) resp->data) = sc->hotchar; 632 break; 633 default: 634 ERROUT(EINVAL); 635 } 636 break; 637 default: 638 ERROUT(EINVAL); 639 } 640done: 641 NG_RESPOND_MSG(error, node, item, resp); 642 NG_FREE_MSG(msg); 643 return (error); 644} 645 646/****************************************************************** 647 INITIALIZATION 648******************************************************************/ 649 650/* 651 * Handle loading and unloading for this node type 652 */ 653static int 654ngt_mod_event(module_t mod, int event, void *data) 655{ 656 /* struct ng_type *const type = data;*/ 657 int s, error = 0; 658 659 switch (event) { 660 case MOD_LOAD: 661 662 /* Register line discipline */ 663 s = spltty(); 664 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) { 665 splx(s); 666 log(LOG_ERR, "%s: can't register line discipline", 667 __func__); 668 return (EIO); 669 } 670 splx(s); 671 break; 672 673 case MOD_UNLOAD: 674 675 /* Unregister line discipline */ 676 s = spltty(); 677 ldisc_deregister(ngt_ldisc); 678 splx(s); 679 break; 680 681 default: 682 error = EOPNOTSUPP; 683 break; 684 } 685 return (error); 686} 687 688