kernel/netgraph7: Replace usage of MALLOC/FREE with kmalloc/kfree here too.
[dragonfly.git] / sys / netgraph7 / ng_tty.c
CommitLineData
b06ebda0 1/*-
22ff886e
AH
2 * (MPSAFE)
3 *
4 * ng_tty.c
5 *
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6 * Copyright (c) 1996-1999 Whistle Communications, Inc.
7 * All rights reserved.
8 *
9 * Subject to the following obligations and disclaimer of warranty, use and
10 * redistribution of this software, in source or object code forms, with or
11 * without modifications are expressly permitted by Whistle Communications;
12 * provided, however, that:
13 * 1. Any and all reproductions of the source or object code must include the
14 * copyright notice above and the following disclaimer of warranties; and
15 * 2. No rights are granted, in any manner or form, to use Whistle
16 * Communications, Inc. trademarks, including the mark "WHISTLE
17 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as
18 * such appears in the above copyright notice or in the software.
19 *
20 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
21 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
22 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
23 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
24 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
25 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
26 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
27 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
28 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
29 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
30 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
31 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
32 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
36 * OF SUCH DAMAGE.
37 *
38 * Author: Archie Cobbs <archie@freebsd.org>
39 *
40 * $FreeBSD: src/sys/netgraph/ng_tty.c,v 1.37 2006/11/06 13:42:03 rwatson Exp $
5a975a3d 41 * $DragonFly: src/sys/netgraph7/ng_tty.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
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42 * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $
43 */
44
45/*
46 * This file implements a terminal line discipline that is also a
47 * netgraph node. Installing this line discipline on a terminal device
48 * instantiates a new netgraph node of this type, which allows access
49 * to the device via the "hook" hook of the node.
50 *
51 * Once the line discipline is installed, you can find out the name
52 * of the corresponding netgraph node via a NGIOCGINFO ioctl().
53 *
54 * Incoming characters are delievered to the hook one at a time, each
55 * in its own mbuf. You may optionally define a ``hotchar,'' which causes
56 * incoming characters to be buffered up until either the hotchar is
57 * seen or the mbuf is full (MHLEN bytes). Then all buffered characters
58 * are immediately delivered.
59 */
60
61#include <sys/param.h>
62#include <sys/systm.h>
63#include <sys/conf.h>
64#include <sys/errno.h>
65#include <sys/fcntl.h>
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66#include <sys/kernel.h>
67#include <sys/malloc.h>
68#include <sys/mbuf.h>
69#include <sys/priv.h>
70#include <sys/socket.h>
71#include <sys/syslog.h>
72#include <sys/tty.h>
73#include <sys/ttycom.h>
74
75#include <net/if.h>
76#include <net/if_var.h>
77
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78#include "ng_message.h"
79#include "netgraph.h"
80#include "ng_tty.h"
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81
82/* Misc defs */
83#define MAX_MBUFQ 3 /* Max number of queued mbufs */
84#define NGT_HIWATER 400 /* High water mark on output */
85
86/* Per-node private info */
87struct ngt_sc {
88 struct tty *tp; /* Terminal device */
89 node_p node; /* Netgraph node */
90 hook_p hook; /* Netgraph hook */
91 struct ifqueue outq; /* Queue of outgoing data */
92 struct mbuf *m; /* Incoming data buffer */
93 short hotchar; /* Hotchar, or -1 if none */
94 u_int flags; /* Flags */
95 struct callout chand; /* See man timeout(9) */
96};
97typedef struct ngt_sc *sc_p;
98
99/* Flags */
100#define FLG_DEBUG 0x0002
101#define FLG_DIE 0x0004
102
103/* Line discipline methods */
104static int ngt_open(struct cdev *dev, struct tty *tp);
105static int ngt_close(struct tty *tp, int flag);
106static int ngt_read(struct tty *tp, struct uio *uio, int flag);
107static int ngt_write(struct tty *tp, struct uio *uio, int flag);
108static int ngt_tioctl(struct tty *tp,
109 u_long cmd, caddr_t data, int flag, struct thread *);
110static int ngt_input(int c, struct tty *tp);
111static int ngt_start(struct tty *tp);
112
113/* Netgraph methods */
114static ng_constructor_t ngt_constructor;
115static ng_rcvmsg_t ngt_rcvmsg;
116static ng_shutdown_t ngt_shutdown;
117static ng_newhook_t ngt_newhook;
118static ng_connect_t ngt_connect;
119static ng_rcvdata_t ngt_rcvdata;
120static ng_disconnect_t ngt_disconnect;
121static int ngt_mod_event(module_t mod, int event, void *data);
122
123/* Other stuff */
124static void ngt_timeout(node_p node, hook_p hook, void *arg1, int arg2);
125
126#define ERROUT(x) do { error = (x); goto done; } while (0)
127
128/* Line discipline descriptor */
129static struct linesw ngt_disc = {
130 .l_open = ngt_open,
131 .l_close = ngt_close,
132 .l_read = ngt_read,
133 .l_write = ngt_write,
134 .l_ioctl = ngt_tioctl,
135 .l_rint = ngt_input,
136 .l_start = ngt_start,
137 .l_modem = ttymodem,
138};
139
140/* Netgraph node type descriptor */
141static struct ng_type typestruct = {
142 .version = NG_ABI_VERSION,
143 .name = NG_TTY_NODE_TYPE,
144 .mod_event = ngt_mod_event,
145 .constructor = ngt_constructor,
146 .rcvmsg = ngt_rcvmsg,
147 .shutdown = ngt_shutdown,
148 .newhook = ngt_newhook,
149 .connect = ngt_connect,
150 .rcvdata = ngt_rcvdata,
151 .disconnect = ngt_disconnect,
152};
153NETGRAPH_INIT(tty, &typestruct);
154
155/*
156 * Locking:
157 *
158 * - node private data and tp->t_lsc is protected by mutex in struct
159 * ifqueue, locking is done using IF_XXX() macros.
160 * - in all tty methods we should acquire node ifqueue mutex, when accessing
161 * private data.
162 * - in _rcvdata() we should use locked versions of IF_{EN,DE}QUEUE() since
163 * we may have multiple _rcvdata() threads.
164 * - when calling any of tty methods from netgraph methods, we should
165 * acquire tty locking (now Giant).
166 *
167 * - ngt_unit is incremented atomically.
168 */
169
170#define NGTLOCK(sc) IF_LOCK(&sc->outq)
171#define NGTUNLOCK(sc) IF_UNLOCK(&sc->outq)
172
173static int ngt_unit;
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()
183 */
184static int
185ngt_open(struct cdev *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 error;
191
192 /* Super-user only */
193 error = priv_check(td, PRIV_NETGRAPH_TTY);
194 if (error)
195 return (error);
196
197 /* Initialize private struct */
fc025606 198 sc = kmalloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO);
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199 if (sc == NULL)
200 return (ENOMEM);
201
22ff886e 202 lwkt_gettoken(&tty_token);
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203 sc->tp = tp;
204 sc->hotchar = tp->t_hotchar = NG_TTY_DFL_HOTCHAR;
205 mtx_init(&sc->outq.ifq_mtx, "ng_tty node+queue", NULL, MTX_DEF);
206 IFQ_SET_MAXLEN(&sc->outq, MAX_MBUFQ);
207
208 NGTLOCK(sc);
209
210 /* Setup netgraph node */
211 error = ng_make_node_common(&typestruct, &sc->node);
212 if (error) {
213 NGTUNLOCK(sc);
fc025606 214 kfree(sc, M_NETGRAPH);
22ff886e 215 lwkt_reltoken(&tty_token);
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216 return (error);
217 }
218
219 atomic_add_int(&ngt_unit, 1);
220 snprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit);
221
222 /* Assign node its name */
223 if ((error = ng_name_node(sc->node, name))) {
224 sc->flags |= FLG_DIE;
225 NGTUNLOCK(sc);
226 NG_NODE_UNREF(sc->node);
227 log(LOG_ERR, "%s: node name exists?\n", name);
22ff886e 228 lwkt_reltoken(&tty_token);
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229 return (error);
230 }
231
232 /* Set back pointers */
233 NG_NODE_SET_PRIVATE(sc->node, sc);
234 tp->t_lsc = sc;
235
22ff886e 236 ng_callout_init_mp(&sc->chand);
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237
238 /*
239 * Pre-allocate cblocks to the an appropriate amount.
240 * I'm not sure what is appropriate.
241 */
242 ttyflush(tp, FREAD | FWRITE);
243 clist_alloc_cblocks(&tp->t_canq, 0, 0);
244 clist_alloc_cblocks(&tp->t_rawq, 0, 0);
245 clist_alloc_cblocks(&tp->t_outq,
246 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER);
247
248 NGTUNLOCK(sc);
249
22ff886e 250 lwkt_reltoken(&tty_token);
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251 return (0);
252}
253
254/*
255 * Line specific close routine, called from device close routine
256 * and from ttioctl. This causes the node to be destroyed as well.
257 */
258static int
259ngt_close(struct tty *tp, int flag)
260{
261 const sc_p sc = (sc_p) tp->t_lsc;
262
22ff886e 263 lwkt_gettoken(&tty_token);
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264 ttyflush(tp, FREAD | FWRITE);
265 clist_free_cblocks(&tp->t_outq);
266 if (sc != NULL) {
267 NGTLOCK(sc);
268 if (callout_pending(&sc->chand))
269 ng_uncallout(&sc->chand, sc->node);
270 tp->t_lsc = NULL;
271 sc->flags |= FLG_DIE;
272 NGTUNLOCK(sc);
273 ng_rmnode_self(sc->node);
274 }
22ff886e 275 lwkt_reltoken(&tty_token);
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276 return (0);
277}
278
279/*
280 * Once the device has been turned into a node, we don't allow reading.
281 */
282static int
283ngt_read(struct tty *tp, struct uio *uio, int flag)
284{
285 return (EIO);
286}
287
288/*
289 * Once the device has been turned into a node, we don't allow writing.
290 */
291static int
292ngt_write(struct tty *tp, struct uio *uio, int flag)
293{
294 return (EIO);
295}
296
297/*
298 * We implement the NGIOCGINFO ioctl() defined in ng_message.h.
299 */
300static int
301ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct thread *td)
302{
303 const sc_p sc = (sc_p) tp->t_lsc;
304
305 if (sc == NULL)
306 /* No node attached */
307 return (0);
308
22ff886e 309 lwkt_gettoken(&tty_token);
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310 switch (cmd) {
311 case NGIOCGINFO:
312 {
313 struct nodeinfo *const ni = (struct nodeinfo *) data;
314 const node_p node = sc->node;
315
316 bzero(ni, sizeof(*ni));
317 NGTLOCK(sc);
318 if (NG_NODE_HAS_NAME(node))
319 strncpy(ni->name, NG_NODE_NAME(node), sizeof(ni->name) - 1);
320 strncpy(ni->type, node->nd_type->name, sizeof(ni->type) - 1);
321 ni->id = (u_int32_t) ng_node2ID(node);
322 ni->hooks = NG_NODE_NUMHOOKS(node);
323 NGTUNLOCK(sc);
324 break;
325 }
326 default:
22ff886e 327 lwkt_reltoken(&tty_token);
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328 return (ENOIOCTL);
329 }
330
22ff886e 331 lwkt_reltoken(&tty_token);
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332 return (0);
333}
334
335/*
336 * Receive data coming from the device. We get one character at
337 * a time, which is kindof silly.
338 *
339 * Full locking of softc is not required, since we are the only
340 * user of sc->m.
341 */
342static int
343ngt_input(int c, struct tty *tp)
344{
345 sc_p sc;
346 node_p node;
347 struct mbuf *m;
348 int error = 0;
349
22ff886e 350 lwkt_gettoken(&tty_token);
b06ebda0 351 sc = (sc_p) tp->t_lsc;
22ff886e 352 if (sc == NULL) {
b06ebda0 353 /* No node attached */
22ff886e 354 lwkt_reltoken(&tty_token);
b06ebda0 355 return (0);
22ff886e 356 }
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357
358 node = sc->node;
359
360 if (tp != sc->tp)
361 panic("ngt_input");
362
363 /* Check for error conditions */
364 if ((tp->t_state & TS_CONNECTED) == 0) {
365 if (sc->flags & FLG_DEBUG)
366 log(LOG_DEBUG, "%s: no carrier\n", NG_NODE_NAME(node));
22ff886e 367 lwkt_reltoken(&tty_token);
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368 return (0);
369 }
370 if (c & TTY_ERRORMASK) {
371 /* framing error or overrun on this char */
372 if (sc->flags & FLG_DEBUG)
373 log(LOG_DEBUG, "%s: line error %x\n",
374 NG_NODE_NAME(node), c & TTY_ERRORMASK);
22ff886e 375 lwkt_reltoken(&tty_token);
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376 return (0);
377 }
378 c &= TTY_CHARMASK;
379
380 /* Get a new header mbuf if we need one */
381 if (!(m = sc->m)) {
5a975a3d 382 MGETHDR(m, MB_DONTWAIT, MT_DATA);
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383 if (!m) {
384 if (sc->flags & FLG_DEBUG)
385 log(LOG_ERR,
386 "%s: can't get mbuf\n", NG_NODE_NAME(node));
22ff886e 387 lwkt_reltoken(&tty_token);
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388 return (ENOBUFS);
389 }
390 m->m_len = m->m_pkthdr.len = 0;
391 m->m_pkthdr.rcvif = NULL;
392 sc->m = m;
393 }
394
395 /* Add char to mbuf */
396 *mtod(m, u_char *) = c;
397 m->m_data++;
398 m->m_len++;
399 m->m_pkthdr.len++;
400
401 /* Ship off mbuf if it's time */
402 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) {
403 m->m_data = m->m_pktdat;
404 sc->m = NULL;
405
406 /*
407 * We have built our mbuf without checking that we actually
408 * have a hook to send it. This was done to avoid
409 * acquiring mutex on each character. Check now.
410 *
411 */
412
413 NGTLOCK(sc);
414 if (sc->hook == NULL) {
415 NGTUNLOCK(sc);
416 m_freem(m);
22ff886e 417 lwkt_reltoken(&tty_token);
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418 return (0); /* XXX: original behavior */
419 }
420 NG_SEND_DATA_ONLY(error, sc->hook, m); /* Will queue */
421 NGTUNLOCK(sc);
422 }
423
22ff886e 424 lwkt_reltoken(&tty_token);
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425 return (error);
426}
427
428/*
429 * This is called when the device driver is ready for more output.
430 * Also called from ngt_rcv_data() when a new mbuf is available for output.
431 */
432static int
433ngt_start(struct tty *tp)
434{
435 const sc_p sc = (sc_p) tp->t_lsc;
436
22ff886e 437 lwkt_gettoken(&tty_token);
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438 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */
439 struct mbuf *m;
440
441 /* Remove first mbuf from queue */
442 IF_DEQUEUE(&sc->outq, m);
443 if (m == NULL)
444 break;
445
446 /* Send as much of it as possible */
447 while (m != NULL) {
448 int sent;
449
450 sent = m->m_len
451 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq);
452 m->m_data += sent;
453 m->m_len -= sent;
454 if (m->m_len > 0)
455 break; /* device can't take no more */
456 m = m_free(m);
457 }
458
459 /* Put remainder of mbuf chain (if any) back on queue */
460 if (m != NULL) {
461 IF_PREPEND(&sc->outq, m);
462 break;
463 }
464 }
465
466 /* Call output process whether or not there is any output. We are
467 * being called in lieu of ttstart and must do what it would. */
468 tt_oproc(tp);
469
470 /* This timeout is needed for operation on a pseudo-tty, because the
471 * pty code doesn't call pppstart after it has drained the t_outq. */
472 /* XXX: outq not locked */
473 if (!IFQ_IS_EMPTY(&sc->outq) && !callout_pending(&sc->chand))
474 ng_callout(&sc->chand, sc->node, NULL, 1, ngt_timeout, NULL, 0);
475
22ff886e 476 lwkt_reltoken(&tty_token);
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477 return (0);
478}
479
480/*
481 * We still have data to output to the device, so try sending more.
482 */
483static void
484ngt_timeout(node_p node, hook_p hook, void *arg1, int arg2)
485{
486 const sc_p sc = NG_NODE_PRIVATE(node);
487
488 mtx_lock(&Giant);
489 ngt_start(sc->tp);
490 mtx_unlock(&Giant);
491}
492
493/******************************************************************
494 NETGRAPH NODE METHODS
495******************************************************************/
496
497/*
498 * Initialize a new node of this type.
499 *
500 * We only allow nodes to be created as a result of setting
501 * the line discipline on a tty, so always return an error if not.
502 */
503static int
504ngt_constructor(node_p node)
505{
506 return (EOPNOTSUPP);
507}
508
509/*
510 * Add a new hook. There can only be one.
511 */
512static int
513ngt_newhook(node_p node, hook_p hook, const char *name)
514{
515 const sc_p sc = NG_NODE_PRIVATE(node);
516
517 if (strcmp(name, NG_TTY_HOOK))
518 return (EINVAL);
519
520 if (sc->hook)
521 return (EISCONN);
522
523 NGTLOCK(sc);
524 sc->hook = hook;
525 NGTUNLOCK(sc);
526
527 return (0);
528}
529
530/*
531 * Set the hook into queueing mode (for outgoing packets),
532 * so that we wont deliver mbuf thru the whole graph holding
533 * tty locks.
534 */
535static int
536ngt_connect(hook_p hook)
537{
538 NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));
539 /*
540 * XXX: While ngt_start() is Giant-locked, queue incoming
541 * packets, too. Otherwise we acquire Giant holding some
542 * IP stack locks, e.g. divinp, and this makes WITNESS scream.
543 */
544 NG_HOOK_FORCE_QUEUE(hook);
545 return (0);
546}
547
548/*
549 * Disconnect the hook
550 */
551static int
552ngt_disconnect(hook_p hook)
553{
554 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
555
556 if (hook != sc->hook)
557 panic(__func__);
558
559 NGTLOCK(sc);
560 sc->hook = NULL;
561 NGTUNLOCK(sc);
562
563 return (0);
564}
565
566/*
567 * Remove this node. The does the netgraph portion of the shutdown.
568 * This should only be called indirectly from ngt_close().
569 *
570 * tp->t_lsc is already NULL, so we should be protected from
571 * tty calls now.
572 */
573static int
574ngt_shutdown(node_p node)
575{
576 const sc_p sc = NG_NODE_PRIVATE(node);
577
578 NGTLOCK(sc);
579 if (!(sc->flags & FLG_DIE)) {
580 NGTUNLOCK(sc);
581 return (EOPNOTSUPP);
582 }
583 NGTUNLOCK(sc);
584
585 /* Free resources */
586 _IF_DRAIN(&sc->outq);
587 mtx_destroy(&(sc)->outq.ifq_mtx);
588 m_freem(sc->m);
589 NG_NODE_UNREF(sc->node);
fc025606 590 kfree(sc, M_NETGRAPH);
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591
592 return (0);
593}
594
595/*
596 * Receive incoming data from netgraph system. Put it on our
597 * output queue and start output if necessary.
598 */
599static int
600ngt_rcvdata(hook_p hook, item_p item)
601{
602 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
603 struct mbuf *m;
604 int qlen;
605
606 if (hook != sc->hook)
607 panic(__func__);
608
609 NGI_GET_M(item, m);
610 NG_FREE_ITEM(item);
611
612 IF_LOCK(&sc->outq);
613 if (_IF_QFULL(&sc->outq)) {
614 _IF_DROP(&sc->outq);
615 IF_UNLOCK(&sc->outq);
616 NG_FREE_M(m);
617 return (ENOBUFS);
618 }
619
620 _IF_ENQUEUE(&sc->outq, m);
621 qlen = sc->outq.ifq_len;
622 IF_UNLOCK(&sc->outq);
623
624 /*
625 * If qlen > 1, then we should already have a scheduled callout.
626 */
627 if (qlen == 1) {
628 mtx_lock(&Giant);
629 ngt_start(sc->tp);
630 mtx_unlock(&Giant);
631 }
632
633 return (0);
634}
635
636/*
637 * Receive control message
638 */
639static int
640ngt_rcvmsg(node_p node, item_p item, hook_p lasthook)
641{
642 const sc_p sc = NG_NODE_PRIVATE(node);
643 struct ng_mesg *msg, *resp = NULL;
644 int error = 0;
645
646 NGI_GET_MSG(item, msg);
647 switch (msg->header.typecookie) {
648 case NGM_TTY_COOKIE:
649 switch (msg->header.cmd) {
650 case NGM_TTY_SET_HOTCHAR:
651 {
652 int hotchar;
653
654 if (msg->header.arglen != sizeof(int))
655 ERROUT(EINVAL);
656 hotchar = *((int *) msg->data);
657 if (hotchar != (u_char) hotchar && hotchar != -1)
658 ERROUT(EINVAL);
659 sc->hotchar = hotchar; /* race condition is OK */
660 break;
661 }
662 case NGM_TTY_GET_HOTCHAR:
5a975a3d 663 NG_MKRESPONSE(resp, msg, sizeof(int), M_WAITOK | M_NULLOK);
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664 if (!resp)
665 ERROUT(ENOMEM);
666 /* Race condition here is OK */
667 *((int *) resp->data) = sc->hotchar;
668 break;
669 default:
670 ERROUT(EINVAL);
671 }
672 break;
673 default:
674 ERROUT(EINVAL);
675 }
676done:
677 NG_RESPOND_MSG(error, node, item, resp);
678 NG_FREE_MSG(msg);
679 return (error);
680}
681
682/******************************************************************
683 INITIALIZATION
684******************************************************************/
685
686/*
687 * Handle loading and unloading for this node type
688 */
689static int
690ngt_mod_event(module_t mod, int event, void *data)
691{
692 int error = 0;
693
694 switch (event) {
695 case MOD_LOAD:
696
697 /* Register line discipline */
698 mtx_lock(&Giant);
699 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) {
700 mtx_unlock(&Giant);
701 log(LOG_ERR, "%s: can't register line discipline",
702 __func__);
703 return (EIO);
704 }
705 mtx_unlock(&Giant);
706 break;
707
708 case MOD_UNLOAD:
709
710 /* Unregister line discipline */
711 mtx_lock(&Giant);
712 ldisc_deregister(ngt_ldisc);
713 mtx_unlock(&Giant);
714 break;
715
716 default:
717 error = EOPNOTSUPP;
718 break;
719 }
720 return (error);
721}