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 69922 2000-12-12 18:52:14Z julian $
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#ifdef __i386__ /* fiddle with the spl locking */
79#include <sys/bus.h>
80#include <machine/ipl.h>
81#endif
82
83/* Misc defs */
84#define MAX_MBUFQ 3 /* Max number of queued mbufs */
85#define NGT_HIWATER 400 /* High water mark on output */
86
87/* Per-node private info */
88struct ngt_sc {
89 struct tty *tp; /* Terminal device */
90 node_p node; /* Netgraph node */
91 hook_p hook; /* Netgraph hook */
92 struct mbuf *m; /* Incoming data buffer */
93 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */
94 short qlen; /* Length of queue */
95 short hotchar; /* Hotchar, or -1 if none */
96 u_int flags; /* Flags */
97 struct callout_handle chand; /* See man timeout(9) */
98};
99typedef struct ngt_sc *sc_p;
100
101/* Flags */
102#define FLG_TIMEOUT 0x0001 /* A timeout is pending */
103#define FLG_DEBUG 0x0002
104
105/* Debugging */
106#ifdef INVARIANTS
107#define QUEUECHECK(sc) \
108 do { \
109 struct mbuf **mp; \
110 int k; \
111 \
112 for (k = 0, mp = &sc->qhead; \
113 k <= MAX_MBUFQ && *mp; \
114 k++, mp = &(*mp)->m_nextpkt); \
115 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \
116 panic(__FUNCTION__ ": queue"); \
117 } while (0)
118#else
119#define QUEUECHECK(sc) do {} while (0)
120#endif
121
122/* Line discipline methods */
123static int ngt_open(dev_t dev, struct tty *tp);
124static int ngt_close(struct tty *tp, int flag);
125static int ngt_read(struct tty *tp, struct uio *uio, int flag);
126static int ngt_write(struct tty *tp, struct uio *uio, int flag);
127static int ngt_tioctl(struct tty *tp,
128 u_long cmd, caddr_t data, int flag, struct proc *);
129static int ngt_input(int c, struct tty *tp);
130static int ngt_start(struct tty *tp);
131
132/* Netgraph methods */
133static ng_constructor_t ngt_constructor;
134static ng_rcvmsg_t ngt_rcvmsg;
135static ng_shutdown_t ngt_shutdown;
136static ng_newhook_t ngt_newhook;
137static ng_connect_t ngt_connect;
138static ng_rcvdata_t ngt_rcvdata;
139static ng_disconnect_t ngt_disconnect;
140static int ngt_mod_event(module_t mod, int event, void *data);
141
142/* Other stuff */
143static void ngt_timeout(void *arg);
144
145#define ERROUT(x) do { error = (x); goto done; } while (0)
146
147/* Line discipline descriptor */
148static 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 */
161static 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 ngt_connect,
171 ngt_rcvdata,
172 ngt_disconnect,
173 NULL
174};
175NETGRAPH_INIT(tty, &typestruct);
176
177static int ngt_unit;
178static int ngt_nodeop_ok; /* OK to create/remove node */
179static int ngt_ldisc;
180
181/******************************************************************
182 LINE DISCIPLINE METHODS
183******************************************************************/
184
185/*
186 * Set our line discipline on the tty.
187 * Called from device open routine or ttioctl() at >= splsofttty()
188 */
189static int
190ngt_open(dev_t dev, struct tty *tp)
191{
192 struct proc *const p = curproc; /* XXX */
193 char name[sizeof(NG_TTY_NODE_TYPE) + 8];
194 sc_p sc;
195 int s, error;
196
197 /* Super-user only */
198 if ((error = suser(p)))
199 return (error);
200 s = splnet();
201 (void) spltty(); /* XXX is this necessary? */
202
203 /* Already installed? */
204 if (tp->t_line == NETGRAPHDISC) {
205 sc = (sc_p) tp->t_sc;
206 if (sc != NULL && sc->tp == tp)
207 goto done;
208 }
209
210 /* Initialize private struct */
211 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO);
212 if (sc == NULL) {
213 error = ENOMEM;
214 goto done;
215 }
216 sc->tp = tp;
217 sc->hotchar = NG_TTY_DFL_HOTCHAR;
218 sc->qtail = &sc->qhead;
219 QUEUECHECK(sc);
220 callout_handle_init(&sc->chand);
221
222 /* Setup netgraph node */
223 ngt_nodeop_ok = 1;
224 error = ng_make_node_common(&typestruct, &sc->node);
225 ngt_nodeop_ok = 0;
226 if (error) {
227 FREE(sc, M_NETGRAPH);
228 goto done;
229 }
230 snprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++);
231
232 /* Set back pointers */
233 sc->node->private = sc;
234 tp->t_sc = (caddr_t) sc;
235
236 /* Assign node its name */
237 if ((error = ng_name_node(sc->node, name))) {
238 log(LOG_ERR, "%s: node name exists?\n", name);
239 ngt_nodeop_ok = 1;
240 ng_rmnode(sc->node);
241 ngt_nodeop_ok = 0;
242 goto done;
243 }
244
245 /*
246 * Pre-allocate cblocks to the an appropriate amount.
247 * I'm not sure what is appropriate.
248 */
249 ttyflush(tp, FREAD | FWRITE);
250 clist_alloc_cblocks(&tp->t_canq, 0, 0);
251 clist_alloc_cblocks(&tp->t_rawq, 0, 0);
252 clist_alloc_cblocks(&tp->t_outq,
253 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER);
254
255done:
256 /* Done */
257 splx(s);
258 return (error);
259}
260
261/*
262 * Line specific close routine, called from device close routine
263 * and from ttioctl at >= splsofttty(). This causes the node to
264 * be destroyed as well.
265 */
266static int
267ngt_close(struct tty *tp, int flag)
268{
269 const sc_p sc = (sc_p) tp->t_sc;
270 int s;
271
272 s = spltty();
273 ttyflush(tp, FREAD | FWRITE);
274 clist_free_cblocks(&tp->t_outq);
275 tp->t_line = 0;
276 if (sc != NULL) {
277 if (sc->flags & FLG_TIMEOUT) {
278 untimeout(ngt_timeout, sc, sc->chand);
279 sc->flags &= ~FLG_TIMEOUT;
280 }
281 ngt_nodeop_ok = 1;
282 ng_rmnode(sc->node);
283 ngt_nodeop_ok = 0;
284 tp->t_sc = NULL;
285 }
286 splx(s);
287 return (0);
288}
289
290/*
291 * Once the device has been turned into a node, we don't allow reading.
292 */
293static int
294ngt_read(struct tty *tp, struct uio *uio, int flag)
295{
296 return (EIO);
297}
298
299/*
300 * Once the device has been turned into a node, we don't allow writing.
301 */
302static int
303ngt_write(struct tty *tp, struct uio *uio, int flag)
304{
305 return (EIO);
306}
307
308/*
309 * We implement the NGIOCGINFO ioctl() defined in ng_message.h.
310 */
311static int
312ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct proc *p)
313{
314 const sc_p sc = (sc_p) tp->t_sc;
315 int s, error = 0;
316
317 s = spltty();
318 switch (cmd) {
319 case NGIOCGINFO:
320 {
321 struct nodeinfo *const ni = (struct nodeinfo *) data;
322 const node_p node = sc->node;
323
324 bzero(ni, sizeof(*ni));
325 if (node->name)
326 strncpy(ni->name, node->name, sizeof(ni->name) - 1);
327 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1);
328 ni->id = (u_int32_t) node;
329 ni->hooks = node->numhooks;
330 break;
331 }
332 default:
333 ERROUT(ENOIOCTL);
334 }
335done:
336 splx(s);
337 return (error);
338}
339
340/*
341 * Receive data coming from the device. We get one character at
342 * a time, which is kindof silly.
343 * Only guaranteed to be at splsofttty() or spltty().
344 */
345static int
346ngt_input(int c, struct tty *tp)
347{
348 const sc_p sc = (sc_p) tp->t_sc;
349 const node_p node = sc->node;
350 struct mbuf *m;
351 int s, error = 0;
352
353 if (!sc || tp != sc->tp)
354 return (0);
355 s = spltty();
356 if (!sc->hook)
357 ERROUT(0);
358
359 /* Check for error conditions */
360 if ((tp->t_state & TS_CONNECTED) == 0) {
361 if (sc->flags & FLG_DEBUG)
362 log(LOG_DEBUG, "%s: no carrier\n", node->name);
363 ERROUT(0);
364 }
365 if (c & TTY_ERRORMASK) {
366 /* framing error or overrun on this char */
367 if (sc->flags & FLG_DEBUG)
368 log(LOG_DEBUG, "%s: line error %x\n",
369 node->name, c & TTY_ERRORMASK);
370 ERROUT(0);
371 }
372 c &= TTY_CHARMASK;
373
374 /* Get a new header mbuf if we need one */
375 if (!(m = sc->m)) {
376 MGETHDR(m, M_DONTWAIT, MT_DATA);
377 if (!m) {
378 if (sc->flags & FLG_DEBUG)
379 log(LOG_ERR,
380 "%s: can't get mbuf\n", node->name);
381 ERROUT(ENOBUFS);
382 }
383 m->m_len = m->m_pkthdr.len = 0;
384 m->m_pkthdr.rcvif = NULL;
385 sc->m = m;
386 }
387
388 /* Add char to mbuf */
389 *mtod(m, u_char *) = c;
390 m->m_data++;
391 m->m_len++;
392 m->m_pkthdr.len++;
393
394 /* Ship off mbuf if it's time */
395 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) {
396 m->m_data = m->m_pktdat;
397 NG_SEND_DATA_ONLY(error, sc->hook, m);
398 sc->m = NULL;
399 }
400done:
401 splx(s);
402 return (error);
403}
404
405/*
406 * This is called when the device driver is ready for more output.
407 * Called from tty system at splsofttty() or spltty().
408 * Also call from ngt_rcv_data() when a new mbuf is available for output.
409 */
410static int
411ngt_start(struct tty *tp)
412{
413 const sc_p sc = (sc_p) tp->t_sc;
414 int s;
415
416 s = spltty();
417 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */
418 struct mbuf *m = sc->qhead;
419
420 /* Remove first mbuf from queue */
421 if (!m)
422 break;
423 if ((sc->qhead = m->m_nextpkt) == NULL)
424 sc->qtail = &sc->qhead;
425 sc->qlen--;
426 QUEUECHECK(sc);
427
428 /* Send as much of it as possible */
429 while (m) {
430 struct mbuf *m2;
431 int sent;
432
433 sent = m->m_len
434 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq);
435 m->m_data += sent;
436 m->m_len -= sent;
437 if (m->m_len > 0)
438 break; /* device can't take no more */
439 MFREE(m, m2);
440 m = m2;
441 }
442
443 /* Put remainder of mbuf chain (if any) back on queue */
444 if (m) {
445 m->m_nextpkt = sc->qhead;
446 sc->qhead = m;
447 if (sc->qtail == &sc->qhead)
448 sc->qtail = &m->m_nextpkt;
449 sc->qlen++;
450 QUEUECHECK(sc);
451 break;
452 }
453 }
454
455 /* Call output process whether or not there is any output. We are
456 * being called in lieu of ttstart and must do what it would. */
457 if (tp->t_oproc != NULL)
458 (*tp->t_oproc) (tp);
459
460 /* This timeout is needed for operation on a pseudo-tty, because the
461 * pty code doesn't call pppstart after it has drained the t_outq. */
462 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) {
463 sc->chand = timeout(ngt_timeout, sc, 1);
464 sc->flags |= FLG_TIMEOUT;
465 }
466 splx(s);
467 return (0);
468}
469
470/*
471 * We still have data to output to the device, so try sending more.
472 */
473static void
474ngt_timeout(void *arg)
475{
476 const sc_p sc = (sc_p) arg;
477 int s;
478
479 s = spltty();
480 sc->flags &= ~FLG_TIMEOUT;
481 ngt_start(sc->tp);
482 splx(s);
483}
484
485/******************************************************************
486 NETGRAPH NODE METHODS
487******************************************************************/
488
489/*
490 * Initialize a new node of this type.
491 *
492 * We only allow nodes to be created as a result of setting
493 * the line discipline on a tty, so always return an error if not.
494 */
495static int
496ngt_constructor(node_p *nodep)
497{
498 if (!ngt_nodeop_ok)
499 return (EOPNOTSUPP);
500 return (ng_make_node_common(&typestruct, nodep));
501}
502
503/*
504 * Add a new hook. There can only be one.
505 */
506static int
507ngt_newhook(node_p node, hook_p hook, const char *name)
508{
509 const sc_p sc = node->private;
510 int s, error = 0;
511
512 if (strcmp(name, NG_TTY_HOOK))
513 return (EINVAL);
514 s = spltty();
515 if (sc->hook)
516 ERROUT(EISCONN);
517 sc->hook = hook;
518done:
519 splx(s);
520 return (error);
521}
522
523/*
524 * set the hooks into queueing mode (for outgoing packets)
525 */
526static int
527ngt_connect(hook_p hook)
528{
529 hook->peer->flags |= HK_QUEUE;
530 return (0);
531}
532
533/*
534 * Disconnect the hook
535 */
536static int
537ngt_disconnect(hook_p hook)
538{
539 const sc_p sc = hook->node->private;
540 int s;
541
542 s = spltty();
543 if (hook != sc->hook)
544 panic(__FUNCTION__);
545 sc->hook = NULL;
546 m_freem(sc->m);
547 sc->m = NULL;
548 splx(s);
549 return (0);
550}
551
552/*
553 * Remove this node. The does the netgraph portion of the shutdown.
554 * This should only be called indirectly from ngt_close().
555 */
556static int
557ngt_shutdown(node_p node)
558{
559 const sc_p sc = node->private;
560
561 if (!ngt_nodeop_ok)
562 return (EOPNOTSUPP);
563 ng_unname(node);
564 ng_cutlinks(node);
565 node->private = NULL;
566 ng_unref(sc->node);
567 m_freem(sc->qhead);
568 m_freem(sc->m);
569 bzero(sc, sizeof(*sc));
570 FREE(sc, M_NETGRAPH);
571 return (0);
572}
573
574/*
575 * Receive incoming data from netgraph system. Put it on our
576 * output queue and start output if necessary.
577 */
578static int
579ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
580 struct mbuf **ret_m, meta_p *ret_meta, struct ng_mesg **resp)
581{
582 const sc_p sc = hook->node->private;
583 int s, error = 0;
584
585 if (hook != sc->hook)
586 panic(__FUNCTION__);
587 NG_FREE_META(meta);
588 s = spltty();
589 if (sc->qlen >= MAX_MBUFQ)
590 ERROUT(ENOBUFS);
591 m->m_nextpkt = NULL;
592 *sc->qtail = m;
593 sc->qtail = &m->m_nextpkt;
594 sc->qlen++;
595 QUEUECHECK(sc);
596 m = NULL;
597 if (sc->qlen == 1)
598 ngt_start(sc->tp);
599done:
600 splx(s);
601 if (m)
602 m_freem(m);
603 return (error);
604}
605
606/*
607 * Receive control message
608 */
609static int
610ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
611 struct ng_mesg **rptr, hook_p lasthook)
612{
613 const sc_p sc = (sc_p) node->private;
614 struct ng_mesg *resp = NULL;
615 int error = 0;
616
617 switch (msg->header.typecookie) {
618 case NGM_TTY_COOKIE:
619 switch (msg->header.cmd) {
620 case NGM_TTY_SET_HOTCHAR:
621 {
622 int hotchar;
623
624 if (msg->header.arglen != sizeof(int))
625 ERROUT(EINVAL);
626 hotchar = *((int *) msg->data);
627 if (hotchar != (u_char) hotchar && hotchar != -1)
628 ERROUT(EINVAL);
629 sc->hotchar = hotchar; /* race condition is OK */
630 break;
631 }
632 case NGM_TTY_GET_HOTCHAR:
633 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT);
634 if (!resp)
635 ERROUT(ENOMEM);
636 /* Race condition here is OK */
637 *((int *) resp->data) = sc->hotchar;
638 break;
639 default:
640 ERROUT(EINVAL);
641 }
642 break;
643 default:
644 ERROUT(EINVAL);
645 }
646 if (rptr)
647 *rptr = resp;
648 else if (resp)
649 FREE(resp, M_NETGRAPH);
650
651done:
652 FREE(msg, M_NETGRAPH);
653 return (error);
654}
655
656/******************************************************************
657 INITIALIZATION
658******************************************************************/
659
660/*
661 * Handle loading and unloading for this node type
662 */
663static int
664ngt_mod_event(module_t mod, int event, void *data)
665{
666 /* struct ng_type *const type = data;*/
667 int s, error = 0;
668
669 switch (event) {
670 case MOD_LOAD:
671
672 /* Register line discipline */
673 s = spltty();
674 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) {
675 splx(s);
676 log(LOG_ERR, "%s: can't register line discipline",
677 __FUNCTION__);
678 return (EIO);
679 }
680 splx(s);
681 break;
682
683 case MOD_UNLOAD:
684
685 /* Unregister line discipline */
686 s = spltty();
687 ldisc_deregister(ngt_ldisc);
688 splx(s);
689 break;
690
691 default:
692 error = EOPNOTSUPP;
693 break;
694 }
695 return (error);
696}
697
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 69922 2000-12-12 18:52:14Z julian $
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#ifdef __i386__ /* fiddle with the spl locking */
79#include <sys/bus.h>
80#include <machine/ipl.h>
81#endif
82
83/* Misc defs */
84#define MAX_MBUFQ 3 /* Max number of queued mbufs */
85#define NGT_HIWATER 400 /* High water mark on output */
86
87/* Per-node private info */
88struct ngt_sc {
89 struct tty *tp; /* Terminal device */
90 node_p node; /* Netgraph node */
91 hook_p hook; /* Netgraph hook */
92 struct mbuf *m; /* Incoming data buffer */
93 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */
94 short qlen; /* Length of queue */
95 short hotchar; /* Hotchar, or -1 if none */
96 u_int flags; /* Flags */
97 struct callout_handle chand; /* See man timeout(9) */
98};
99typedef struct ngt_sc *sc_p;
100
101/* Flags */
102#define FLG_TIMEOUT 0x0001 /* A timeout is pending */
103#define FLG_DEBUG 0x0002
104
105/* Debugging */
106#ifdef INVARIANTS
107#define QUEUECHECK(sc) \
108 do { \
109 struct mbuf **mp; \
110 int k; \
111 \
112 for (k = 0, mp = &sc->qhead; \
113 k <= MAX_MBUFQ && *mp; \
114 k++, mp = &(*mp)->m_nextpkt); \
115 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \
116 panic(__FUNCTION__ ": queue"); \
117 } while (0)
118#else
119#define QUEUECHECK(sc) do {} while (0)
120#endif
121
122/* Line discipline methods */
123static int ngt_open(dev_t dev, struct tty *tp);
124static int ngt_close(struct tty *tp, int flag);
125static int ngt_read(struct tty *tp, struct uio *uio, int flag);
126static int ngt_write(struct tty *tp, struct uio *uio, int flag);
127static int ngt_tioctl(struct tty *tp,
128 u_long cmd, caddr_t data, int flag, struct proc *);
129static int ngt_input(int c, struct tty *tp);
130static int ngt_start(struct tty *tp);
131
132/* Netgraph methods */
133static ng_constructor_t ngt_constructor;
134static ng_rcvmsg_t ngt_rcvmsg;
135static ng_shutdown_t ngt_shutdown;
136static ng_newhook_t ngt_newhook;
137static ng_connect_t ngt_connect;
138static ng_rcvdata_t ngt_rcvdata;
139static ng_disconnect_t ngt_disconnect;
140static int ngt_mod_event(module_t mod, int event, void *data);
141
142/* Other stuff */
143static void ngt_timeout(void *arg);
144
145#define ERROUT(x) do { error = (x); goto done; } while (0)
146
147/* Line discipline descriptor */
148static 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 */
161static 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 ngt_connect,
171 ngt_rcvdata,
172 ngt_disconnect,
173 NULL
174};
175NETGRAPH_INIT(tty, &typestruct);
176
177static int ngt_unit;
178static int ngt_nodeop_ok; /* OK to create/remove node */
179static int ngt_ldisc;
180
181/******************************************************************
182 LINE DISCIPLINE METHODS
183******************************************************************/
184
185/*
186 * Set our line discipline on the tty.
187 * Called from device open routine or ttioctl() at >= splsofttty()
188 */
189static int
190ngt_open(dev_t dev, struct tty *tp)
191{
192 struct proc *const p = curproc; /* XXX */
193 char name[sizeof(NG_TTY_NODE_TYPE) + 8];
194 sc_p sc;
195 int s, error;
196
197 /* Super-user only */
198 if ((error = suser(p)))
199 return (error);
200 s = splnet();
201 (void) spltty(); /* XXX is this necessary? */
202
203 /* Already installed? */
204 if (tp->t_line == NETGRAPHDISC) {
205 sc = (sc_p) tp->t_sc;
206 if (sc != NULL && sc->tp == tp)
207 goto done;
208 }
209
210 /* Initialize private struct */
211 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO);
212 if (sc == NULL) {
213 error = ENOMEM;
214 goto done;
215 }
216 sc->tp = tp;
217 sc->hotchar = NG_TTY_DFL_HOTCHAR;
218 sc->qtail = &sc->qhead;
219 QUEUECHECK(sc);
220 callout_handle_init(&sc->chand);
221
222 /* Setup netgraph node */
223 ngt_nodeop_ok = 1;
224 error = ng_make_node_common(&typestruct, &sc->node);
225 ngt_nodeop_ok = 0;
226 if (error) {
227 FREE(sc, M_NETGRAPH);
228 goto done;
229 }
230 snprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++);
231
232 /* Set back pointers */
233 sc->node->private = sc;
234 tp->t_sc = (caddr_t) sc;
235
236 /* Assign node its name */
237 if ((error = ng_name_node(sc->node, name))) {
238 log(LOG_ERR, "%s: node name exists?\n", name);
239 ngt_nodeop_ok = 1;
240 ng_rmnode(sc->node);
241 ngt_nodeop_ok = 0;
242 goto done;
243 }
244
245 /*
246 * Pre-allocate cblocks to the an appropriate amount.
247 * I'm not sure what is appropriate.
248 */
249 ttyflush(tp, FREAD | FWRITE);
250 clist_alloc_cblocks(&tp->t_canq, 0, 0);
251 clist_alloc_cblocks(&tp->t_rawq, 0, 0);
252 clist_alloc_cblocks(&tp->t_outq,
253 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER);
254
255done:
256 /* Done */
257 splx(s);
258 return (error);
259}
260
261/*
262 * Line specific close routine, called from device close routine
263 * and from ttioctl at >= splsofttty(). This causes the node to
264 * be destroyed as well.
265 */
266static int
267ngt_close(struct tty *tp, int flag)
268{
269 const sc_p sc = (sc_p) tp->t_sc;
270 int s;
271
272 s = spltty();
273 ttyflush(tp, FREAD | FWRITE);
274 clist_free_cblocks(&tp->t_outq);
275 tp->t_line = 0;
276 if (sc != NULL) {
277 if (sc->flags & FLG_TIMEOUT) {
278 untimeout(ngt_timeout, sc, sc->chand);
279 sc->flags &= ~FLG_TIMEOUT;
280 }
281 ngt_nodeop_ok = 1;
282 ng_rmnode(sc->node);
283 ngt_nodeop_ok = 0;
284 tp->t_sc = NULL;
285 }
286 splx(s);
287 return (0);
288}
289
290/*
291 * Once the device has been turned into a node, we don't allow reading.
292 */
293static int
294ngt_read(struct tty *tp, struct uio *uio, int flag)
295{
296 return (EIO);
297}
298
299/*
300 * Once the device has been turned into a node, we don't allow writing.
301 */
302static int
303ngt_write(struct tty *tp, struct uio *uio, int flag)
304{
305 return (EIO);
306}
307
308/*
309 * We implement the NGIOCGINFO ioctl() defined in ng_message.h.
310 */
311static int
312ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct proc *p)
313{
314 const sc_p sc = (sc_p) tp->t_sc;
315 int s, error = 0;
316
317 s = spltty();
318 switch (cmd) {
319 case NGIOCGINFO:
320 {
321 struct nodeinfo *const ni = (struct nodeinfo *) data;
322 const node_p node = sc->node;
323
324 bzero(ni, sizeof(*ni));
325 if (node->name)
326 strncpy(ni->name, node->name, sizeof(ni->name) - 1);
327 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1);
328 ni->id = (u_int32_t) node;
329 ni->hooks = node->numhooks;
330 break;
331 }
332 default:
333 ERROUT(ENOIOCTL);
334 }
335done:
336 splx(s);
337 return (error);
338}
339
340/*
341 * Receive data coming from the device. We get one character at
342 * a time, which is kindof silly.
343 * Only guaranteed to be at splsofttty() or spltty().
344 */
345static int
346ngt_input(int c, struct tty *tp)
347{
348 const sc_p sc = (sc_p) tp->t_sc;
349 const node_p node = sc->node;
350 struct mbuf *m;
351 int s, error = 0;
352
353 if (!sc || tp != sc->tp)
354 return (0);
355 s = spltty();
356 if (!sc->hook)
357 ERROUT(0);
358
359 /* Check for error conditions */
360 if ((tp->t_state & TS_CONNECTED) == 0) {
361 if (sc->flags & FLG_DEBUG)
362 log(LOG_DEBUG, "%s: no carrier\n", node->name);
363 ERROUT(0);
364 }
365 if (c & TTY_ERRORMASK) {
366 /* framing error or overrun on this char */
367 if (sc->flags & FLG_DEBUG)
368 log(LOG_DEBUG, "%s: line error %x\n",
369 node->name, c & TTY_ERRORMASK);
370 ERROUT(0);
371 }
372 c &= TTY_CHARMASK;
373
374 /* Get a new header mbuf if we need one */
375 if (!(m = sc->m)) {
376 MGETHDR(m, M_DONTWAIT, MT_DATA);
377 if (!m) {
378 if (sc->flags & FLG_DEBUG)
379 log(LOG_ERR,
380 "%s: can't get mbuf\n", node->name);
381 ERROUT(ENOBUFS);
382 }
383 m->m_len = m->m_pkthdr.len = 0;
384 m->m_pkthdr.rcvif = NULL;
385 sc->m = m;
386 }
387
388 /* Add char to mbuf */
389 *mtod(m, u_char *) = c;
390 m->m_data++;
391 m->m_len++;
392 m->m_pkthdr.len++;
393
394 /* Ship off mbuf if it's time */
395 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) {
396 m->m_data = m->m_pktdat;
397 NG_SEND_DATA_ONLY(error, sc->hook, m);
398 sc->m = NULL;
399 }
400done:
401 splx(s);
402 return (error);
403}
404
405/*
406 * This is called when the device driver is ready for more output.
407 * Called from tty system at splsofttty() or spltty().
408 * Also call from ngt_rcv_data() when a new mbuf is available for output.
409 */
410static int
411ngt_start(struct tty *tp)
412{
413 const sc_p sc = (sc_p) tp->t_sc;
414 int s;
415
416 s = spltty();
417 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */
418 struct mbuf *m = sc->qhead;
419
420 /* Remove first mbuf from queue */
421 if (!m)
422 break;
423 if ((sc->qhead = m->m_nextpkt) == NULL)
424 sc->qtail = &sc->qhead;
425 sc->qlen--;
426 QUEUECHECK(sc);
427
428 /* Send as much of it as possible */
429 while (m) {
430 struct mbuf *m2;
431 int sent;
432
433 sent = m->m_len
434 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq);
435 m->m_data += sent;
436 m->m_len -= sent;
437 if (m->m_len > 0)
438 break; /* device can't take no more */
439 MFREE(m, m2);
440 m = m2;
441 }
442
443 /* Put remainder of mbuf chain (if any) back on queue */
444 if (m) {
445 m->m_nextpkt = sc->qhead;
446 sc->qhead = m;
447 if (sc->qtail == &sc->qhead)
448 sc->qtail = &m->m_nextpkt;
449 sc->qlen++;
450 QUEUECHECK(sc);
451 break;
452 }
453 }
454
455 /* Call output process whether or not there is any output. We are
456 * being called in lieu of ttstart and must do what it would. */
457 if (tp->t_oproc != NULL)
458 (*tp->t_oproc) (tp);
459
460 /* This timeout is needed for operation on a pseudo-tty, because the
461 * pty code doesn't call pppstart after it has drained the t_outq. */
462 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) {
463 sc->chand = timeout(ngt_timeout, sc, 1);
464 sc->flags |= FLG_TIMEOUT;
465 }
466 splx(s);
467 return (0);
468}
469
470/*
471 * We still have data to output to the device, so try sending more.
472 */
473static void
474ngt_timeout(void *arg)
475{
476 const sc_p sc = (sc_p) arg;
477 int s;
478
479 s = spltty();
480 sc->flags &= ~FLG_TIMEOUT;
481 ngt_start(sc->tp);
482 splx(s);
483}
484
485/******************************************************************
486 NETGRAPH NODE METHODS
487******************************************************************/
488
489/*
490 * Initialize a new node of this type.
491 *
492 * We only allow nodes to be created as a result of setting
493 * the line discipline on a tty, so always return an error if not.
494 */
495static int
496ngt_constructor(node_p *nodep)
497{
498 if (!ngt_nodeop_ok)
499 return (EOPNOTSUPP);
500 return (ng_make_node_common(&typestruct, nodep));
501}
502
503/*
504 * Add a new hook. There can only be one.
505 */
506static int
507ngt_newhook(node_p node, hook_p hook, const char *name)
508{
509 const sc_p sc = node->private;
510 int s, error = 0;
511
512 if (strcmp(name, NG_TTY_HOOK))
513 return (EINVAL);
514 s = spltty();
515 if (sc->hook)
516 ERROUT(EISCONN);
517 sc->hook = hook;
518done:
519 splx(s);
520 return (error);
521}
522
523/*
524 * set the hooks into queueing mode (for outgoing packets)
525 */
526static int
527ngt_connect(hook_p hook)
528{
529 hook->peer->flags |= HK_QUEUE;
530 return (0);
531}
532
533/*
534 * Disconnect the hook
535 */
536static int
537ngt_disconnect(hook_p hook)
538{
539 const sc_p sc = hook->node->private;
540 int s;
541
542 s = spltty();
543 if (hook != sc->hook)
544 panic(__FUNCTION__);
545 sc->hook = NULL;
546 m_freem(sc->m);
547 sc->m = NULL;
548 splx(s);
549 return (0);
550}
551
552/*
553 * Remove this node. The does the netgraph portion of the shutdown.
554 * This should only be called indirectly from ngt_close().
555 */
556static int
557ngt_shutdown(node_p node)
558{
559 const sc_p sc = node->private;
560
561 if (!ngt_nodeop_ok)
562 return (EOPNOTSUPP);
563 ng_unname(node);
564 ng_cutlinks(node);
565 node->private = NULL;
566 ng_unref(sc->node);
567 m_freem(sc->qhead);
568 m_freem(sc->m);
569 bzero(sc, sizeof(*sc));
570 FREE(sc, M_NETGRAPH);
571 return (0);
572}
573
574/*
575 * Receive incoming data from netgraph system. Put it on our
576 * output queue and start output if necessary.
577 */
578static int
579ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
580 struct mbuf **ret_m, meta_p *ret_meta, struct ng_mesg **resp)
581{
582 const sc_p sc = hook->node->private;
583 int s, error = 0;
584
585 if (hook != sc->hook)
586 panic(__FUNCTION__);
587 NG_FREE_META(meta);
588 s = spltty();
589 if (sc->qlen >= MAX_MBUFQ)
590 ERROUT(ENOBUFS);
591 m->m_nextpkt = NULL;
592 *sc->qtail = m;
593 sc->qtail = &m->m_nextpkt;
594 sc->qlen++;
595 QUEUECHECK(sc);
596 m = NULL;
597 if (sc->qlen == 1)
598 ngt_start(sc->tp);
599done:
600 splx(s);
601 if (m)
602 m_freem(m);
603 return (error);
604}
605
606/*
607 * Receive control message
608 */
609static int
610ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
611 struct ng_mesg **rptr, hook_p lasthook)
612{
613 const sc_p sc = (sc_p) node->private;
614 struct ng_mesg *resp = NULL;
615 int error = 0;
616
617 switch (msg->header.typecookie) {
618 case NGM_TTY_COOKIE:
619 switch (msg->header.cmd) {
620 case NGM_TTY_SET_HOTCHAR:
621 {
622 int hotchar;
623
624 if (msg->header.arglen != sizeof(int))
625 ERROUT(EINVAL);
626 hotchar = *((int *) msg->data);
627 if (hotchar != (u_char) hotchar && hotchar != -1)
628 ERROUT(EINVAL);
629 sc->hotchar = hotchar; /* race condition is OK */
630 break;
631 }
632 case NGM_TTY_GET_HOTCHAR:
633 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT);
634 if (!resp)
635 ERROUT(ENOMEM);
636 /* Race condition here is OK */
637 *((int *) resp->data) = sc->hotchar;
638 break;
639 default:
640 ERROUT(EINVAL);
641 }
642 break;
643 default:
644 ERROUT(EINVAL);
645 }
646 if (rptr)
647 *rptr = resp;
648 else if (resp)
649 FREE(resp, M_NETGRAPH);
650
651done:
652 FREE(msg, M_NETGRAPH);
653 return (error);
654}
655
656/******************************************************************
657 INITIALIZATION
658******************************************************************/
659
660/*
661 * Handle loading and unloading for this node type
662 */
663static int
664ngt_mod_event(module_t mod, int event, void *data)
665{
666 /* struct ng_type *const type = data;*/
667 int s, error = 0;
668
669 switch (event) {
670 case MOD_LOAD:
671
672 /* Register line discipline */
673 s = spltty();
674 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) {
675 splx(s);
676 log(LOG_ERR, "%s: can't register line discipline",
677 __FUNCTION__);
678 return (EIO);
679 }
680 splx(s);
681 break;
682
683 case MOD_UNLOAD:
684
685 /* Unregister line discipline */
686 s = spltty();
687 ldisc_deregister(ngt_ldisc);
688 splx(s);
689 break;
690
691 default:
692 error = EOPNOTSUPP;
693 break;
694 }
695 return (error);
696}
697