FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_tty.c
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: releng/5.0/sys/netgraph/ng_tty.c 93593 2002-04-01 21:31:13Z jhb $
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 */
83 struct 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 };
94 typedef 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 */
118 static int ngt_open(dev_t dev, struct tty *tp);
119 static int ngt_close(struct tty *tp, int flag);
120 static int ngt_read(struct tty *tp, struct uio *uio, int flag);
121 static int ngt_write(struct tty *tp, struct uio *uio, int flag);
122 static int ngt_tioctl(struct tty *tp,
123 u_long cmd, caddr_t data, int flag, struct thread *);
124 static int ngt_input(int c, struct tty *tp);
125 static int ngt_start(struct tty *tp);
126
127 /* Netgraph methods */
128 static ng_constructor_t ngt_constructor;
129 static ng_rcvmsg_t ngt_rcvmsg;
130 static ng_shutdown_t ngt_shutdown;
131 static ng_newhook_t ngt_newhook;
132 static ng_connect_t ngt_connect;
133 static ng_rcvdata_t ngt_rcvdata;
134 static ng_disconnect_t ngt_disconnect;
135 static int ngt_mod_event(module_t mod, int event, void *data);
136
137 /* Other stuff */
138 static void ngt_timeout(void *arg);
139
140 #define ERROUT(x) do { error = (x); goto done; } while (0)
141
142 /* Line discipline descriptor */
143 static 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 */
156 static 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 };
170 NETGRAPH_INIT(tty, &typestruct);
171
172 static int ngt_unit;
173 static int ngt_nodeop_ok; /* OK to create/remove node */
174 static 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 */
184 static int
185 ngt_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
250 done:
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 */
261 static int
262 ngt_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 */
288 static int
289 ngt_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 */
297 static int
298 ngt_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 */
306 static int
307 ngt_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 }
330 done:
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 */
340 static int
341 ngt_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 }
395 done:
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 */
405 static int
406 ngt_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 */
466 static void
467 ngt_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 */
488 static int
489 ngt_constructor(node_p node)
490 {
491 return (EOPNOTSUPP);
492 }
493
494 /*
495 * Add a new hook. There can only be one.
496 */
497 static int
498 ngt_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;
509 done:
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 */
518 static int
519 ngt_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 */
529 static int
530 ngt_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 */
549 static int
550 ngt_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 */
569 static int
570 ngt_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);
592 done:
593 splx(s);
594 if (m)
595 m_freem(m);
596 return (error);
597 }
598
599 /*
600 * Receive control message
601 */
602 static int
603 ngt_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 }
640 done:
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 */
653 static int
654 ngt_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
Cache object: 5ff054a6d13a4d56afe97df54926ae45
|