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 * $FreeBSD$
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 */
89 struct 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 };
100 typedef 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 */
124 static int ngt_open(dev_t dev, struct tty *tp);
125 static int ngt_close(struct tty *tp, int flag);
126 static int ngt_read(struct tty *tp, struct uio *uio, int flag);
127 static int ngt_write(struct tty *tp, struct uio *uio, int flag);
128 static int ngt_tioctl(struct tty *tp,
129 u_long cmd, caddr_t data, int flag, struct proc *);
130 static int ngt_input(int c, struct tty *tp);
131 static int ngt_start(struct tty *tp);
132
133 /* Netgraph methods */
134 static ng_constructor_t ngt_constructor;
135 static ng_rcvmsg_t ngt_rcvmsg;
136 static ng_shutdown_t ngt_shutdown;
137 static ng_newhook_t ngt_newhook;
138 static ng_rcvdata_t ngt_rcvdata;
139 static ng_disconnect_t ngt_disconnect;
140 static int ngt_mod_event(module_t mod, int event, void *data);
141
142 /* Other stuff */
143 static void ngt_timeout(void *arg);
144
145 #define ERROUT(x) do { error = (x); goto done; } while (0)
146
147 /* Line discipline descriptor */
148 static 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 */
161 static 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 };
176 NETGRAPH_INIT(tty, &typestruct);
177
178 static int ngt_unit;
179 static int ngt_nodeop_ok; /* OK to create/remove node */
180 static 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 */
190 static int
191 ngt_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->p_ucred, &p->p_acflag)))
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
257 done:
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 */
268 static int
269 ngt_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 */
295 static int
296 ngt_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 */
304 static int
305 ngt_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 */
313 static int
314 ngt_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 }
337 done:
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 */
347 static int
348 ngt_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 }
402 done:
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 */
412 static int
413 ngt_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 */
475 static void
476 ngt_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 */
497 static int
498 ngt_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 */
508 static int
509 ngt_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;
520 done:
521 splx(s);
522 return (error);
523 }
524
525 /*
526 * Disconnect the hook
527 */
528 static int
529 ngt_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 */
548 static int
549 ngt_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 */
570 static int
571 ngt_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);
590 done:
591 splx(s);
592 if (m)
593 m_freem(m);
594 return (error);
595 }
596
597 /*
598 * Receive control message
599 */
600 static int
601 ngt_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
642 done:
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 */
654 static int
655 ngt_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
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