xref: /freebsd/sys/netgraph/ng_device.c (revision 81755e6e) 
1 /*
2  * Copyright (c) 2002 Mark Santcroos <marks@ripe.net>
3  * Copyright (c) 2004 Gleb Smirnoff <glebius@FreeBSD.org>
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  *
25  * Netgraph "device" node
26  *
27  * This node presents a /dev/ngd%d device that interfaces to an other
28  * netgraph node.
29  *
30  * $FreeBSD$
31  *
32  */
33 
34 #if 0
35 #define	DBG do { printf("ng_device: %s\n", __func__ ); } while (0)
36 #else
37 #define	DBG do {} while (0)
38 #endif
39 
40 #include <sys/param.h>
41 #include <sys/conf.h>
42 #include <sys/ioccom.h>
43 #include <sys/kernel.h>
44 #include <sys/malloc.h>
45 #include <sys/mbuf.h>
46 #include <sys/poll.h>
47 #include <sys/queue.h>
48 #include <sys/socket.h>
49 #include <sys/systm.h>
50 #include <sys/uio.h>
51 #include <sys/vnode.h>
52 
53 #include <net/if.h>
54 #include <net/if_var.h>
55 #include <netinet/in.h>
56 #include <netinet/in_systm.h>
57 #include <netinet/ip.h>
58 
59 #include <netgraph/ng_message.h>
60 #include <netgraph/netgraph.h>
61 #include <netgraph/ng_device.h>
62 
63 #define	ERROUT(x) do { error = (x); goto done; } while (0)
64 
65 /* Netgraph methods */
66 static ng_constructor_t	ng_device_constructor;
67 static ng_rcvmsg_t	ng_device_rcvmsg;
68 static ng_shutdown_t	ng_device_shutdown;
69 static ng_newhook_t	ng_device_newhook;
70 static ng_rcvdata_t	ng_device_rcvdata;
71 static ng_disconnect_t	ng_device_disconnect;
72 
73 /* Netgraph type */
74 static struct ng_type ngd_typestruct = {
75 	.version =	NG_ABI_VERSION,
76 	.name =		NG_DEVICE_NODE_TYPE,
77 	.constructor =	ng_device_constructor,
78 	.rcvmsg	=	ng_device_rcvmsg,
79 	.shutdown = 	ng_device_shutdown,
80 	.newhook =	ng_device_newhook,
81 	.rcvdata =	ng_device_rcvdata,
82 	.disconnect =	ng_device_disconnect,
83 };
84 NETGRAPH_INIT(device, &ngd_typestruct);
85 
86 /* per node data */
87 struct ngd_private {
88 	struct	ifqueue	readq;
89 	SLIST_ENTRY(ngd_private) links;
90 	struct	ng_node	*node;
91 	struct	ng_hook	*hook;
92 	struct	cdev	*ngddev;
93 	struct	mtx	ngd_mtx;
94 	int 		unit;
95 	uint16_t	flags;
96 #define	NGDF_OPEN	0x0001
97 #define	NGDF_RWAIT	0x0002
98 };
99 typedef struct ngd_private *priv_p;
100 
101 /* List of all active nodes and mutex to protect it */
102 static SLIST_HEAD(, ngd_private) ngd_nodes = SLIST_HEAD_INITIALIZER(ngd_nodes);
103 static struct mtx	ng_device_mtx;
104 MTX_SYSINIT(ng_device, &ng_device_mtx, "ng_device", MTX_DEF);
105 
106 /* Maximum number of NGD devices */
107 #define MAX_NGD	25	/* should be more than enough for now */
108 
109 static d_close_t ngdclose;
110 static d_open_t ngdopen;
111 static d_read_t ngdread;
112 static d_write_t ngdwrite;
113 #if 0
114 static d_ioctl_t ngdioctl;
115 #endif
116 static d_poll_t ngdpoll;
117 
118 static struct cdevsw ngd_cdevsw = {
119 	.d_version =	D_VERSION,
120 	.d_open =	ngdopen,
121 	.d_close =	ngdclose,
122 	.d_read =	ngdread,
123 	.d_write =	ngdwrite,
124 #if 0
125 	.d_ioctl =	ngdioctl,
126 #endif
127 	.d_poll =	ngdpoll,
128 	.d_name =	NG_DEVICE_DEVNAME,
129 };
130 
131 /* Helper functions */
132 static int get_free_unit(void);
133 
134 /******************************************************************************
135  *  Netgraph methods
136  ******************************************************************************/
137 
138 /*
139  * create new node
140  */
141 static int
142 ng_device_constructor(node_p node)
143 {
144 	priv_p	priv;
145 
146 	DBG;
147 
148 	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
149 	if (priv == NULL)
150 		return (ENOMEM);
151 
152 	mtx_init(&priv->ngd_mtx, "ng_device", NULL, MTX_DEF);
153 	mtx_lock(&priv->ngd_mtx);
154 
155 	mtx_lock(&ng_device_mtx);
156 
157 	priv->unit = get_free_unit();
158 	if(priv->unit < 0) {
159 		printf("%s: No free unit found by get_free_unit(), "
160 				"increase MAX_NGD\n",__func__);
161 		mtx_unlock(&ng_device_mtx);
162 		mtx_destroy(&priv->ngd_mtx);
163 		FREE(priv, M_NETGRAPH);
164 		return(EINVAL);
165 	}
166 
167 	priv->ngddev = make_dev(&ngd_cdevsw, unit2minor(priv->unit), UID_ROOT,
168 	    GID_WHEEL, 0600, NG_DEVICE_DEVNAME "%d", priv->unit);
169 	if(priv->ngddev == NULL) {
170 		printf("%s(): make_dev() failed\n",__func__);
171 		mtx_unlock(&ng_device_mtx);
172 		mtx_destroy(&priv->ngd_mtx);
173 		FREE(priv, M_NETGRAPH);
174 		return(EINVAL);
175 	}
176 
177 	SLIST_INSERT_HEAD(&ngd_nodes, priv, links);
178 
179 	mtx_unlock(&ng_device_mtx);
180 
181 	mtx_init(&priv->readq.ifq_mtx, "ng_device queue", NULL, MTX_DEF);
182 	IFQ_SET_MAXLEN(&priv->readq, ifqmaxlen);
183 
184 	/* Link everything together */
185 	NG_NODE_SET_PRIVATE(node, priv);
186 	priv->node = node;
187 	priv->ngddev->si_drv1 = priv;
188 
189 	mtx_unlock(&priv->ngd_mtx);
190 
191 	return(0);
192 }
193 
194 /*
195  * Process control message.
196  */
197 
198 static int
199 ng_device_rcvmsg(node_p node, item_p item, hook_p lasthook)
200 {
201 	const priv_p priv = NG_NODE_PRIVATE(node);
202 	struct ng_mesg *msg;
203 	struct ng_mesg *resp = NULL;
204 	int error = 0;
205 
206 	NGI_GET_MSG(item, msg);
207 
208 	if (msg->header.typecookie == NGM_DEVICE_COOKIE) {
209 		switch (msg->header.cmd) {
210 		case NGM_DEVICE_GET_DEVNAME:
211 			/* XXX: Fix when NGD_MAX us bigger */
212 			NG_MKRESPONSE(resp, msg,
213 			    strlen(NG_DEVICE_DEVNAME) + 3, M_NOWAIT);
214 
215 			if (resp == NULL)
216 				ERROUT(ENOMEM);
217 
218 			strlcpy((char *)resp->data, priv->ngddev->si_name,
219 			    strlen(priv->ngddev->si_name) + 1);
220 			break;
221 
222 		default:
223 			error = EINVAL;
224 			break;
225 		}
226 	} else
227 		error = EINVAL;
228 
229 done:
230 	NG_RESPOND_MSG(error, node, item, resp);
231 	NG_FREE_MSG(msg);
232 	return (error);
233 }
234 
235 /*
236  * Accept incoming hook. We support only one hook per node.
237  */
238 static int
239 ng_device_newhook(node_p node, hook_p hook, const char *name)
240 {
241 	priv_p priv = NG_NODE_PRIVATE(node);
242 
243 	DBG;
244 
245 	/* We have only one hook per node */
246 	if (priv->hook != NULL)
247 		return (EISCONN);
248 
249 	priv->hook = hook;
250 
251 	return(0);
252 }
253 
254 /*
255  * Receive data from hook, write it to device.
256  */
257 static int
258 ng_device_rcvdata(hook_p hook, item_p item)
259 {
260 	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
261 	struct mbuf *m;
262 
263 	DBG;
264 
265 	NGI_GET_M(item, m);
266 	NG_FREE_ITEM(item);
267 
268 	IF_LOCK(&priv->readq);
269 	if (_IF_QFULL(&priv->readq)) {
270 		_IF_DROP(&priv->readq);
271 		IF_UNLOCK(&priv->readq);
272 		NG_FREE_M(m);
273 		return (ENOBUFS);
274 	}
275 
276 	_IF_ENQUEUE(&priv->readq, m);
277 	IF_UNLOCK(&priv->readq);
278 	mtx_lock(&priv->ngd_mtx);
279 	if (priv->flags & NGDF_RWAIT) {
280 		priv->flags &= ~NGDF_RWAIT;
281 		wakeup(priv);
282 	}
283 	mtx_unlock(&priv->ngd_mtx);
284 
285 	return(0);
286 }
287 
288 /*
289  * Removal of the hook destroys the node.
290  */
291 static int
292 ng_device_disconnect(hook_p hook)
293 {
294 	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
295 
296 	DBG;
297 
298 	destroy_dev(priv->ngddev);
299 	mtx_destroy(&priv->ngd_mtx);
300 
301 	mtx_lock(&ng_device_mtx);
302 	SLIST_REMOVE(&ngd_nodes, priv, ngd_private, links);
303 	mtx_unlock(&ng_device_mtx);
304 
305 	IF_DRAIN(&priv->readq);
306 	mtx_destroy(&(priv)->readq.ifq_mtx);
307 
308 	FREE(priv, M_NETGRAPH);
309 
310 	ng_rmnode_self(NG_HOOK_NODE(hook));
311 
312 	return(0);
313 }
314 
315 /*
316  * Node shutdown. Everything is already done in disconnect method.
317  */
318 static int
319 ng_device_shutdown(node_p node)
320 {
321 	NG_NODE_UNREF(node);
322 	return (0);
323 }
324 
325 /******************************************************************************
326  *  Device methods
327  ******************************************************************************/
328 
329 /*
330  * the device is opened
331  */
332 static int
333 ngdopen(struct cdev *dev, int flag, int mode, struct thread *td)
334 {
335 	priv_p	priv = (priv_p )dev->si_drv1;
336 
337 	DBG;
338 
339 	mtx_lock(&priv->ngd_mtx);
340 	priv->flags |= NGDF_OPEN;
341 	mtx_unlock(&priv->ngd_mtx);
342 
343 	return(0);
344 }
345 
346 /*
347  * the device is closed
348  */
349 static int
350 ngdclose(struct cdev *dev, int flag, int mode, struct thread *td)
351 {
352 	priv_p	priv = (priv_p )dev->si_drv1;
353 
354 	DBG;
355 	mtx_lock(&priv->ngd_mtx);
356 	priv->flags &= ~NGDF_OPEN;
357 	mtx_unlock(&priv->ngd_mtx);
358 
359 	return(0);
360 }
361 
362 #if 0	/*
363 	 * The ioctl is transformed into netgraph control message.
364 	 * We do not process them, yet.
365 	 */
366 /*
367  * process ioctl
368  *
369  * they are translated into netgraph messages and passed on
370  *
371  */
372 static int
373 ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
374 {
375 	struct ngd_softc *sc = &ngd_softc;
376 	struct ngd_connection * connection = NULL;
377 	struct ngd_connection * tmp;
378 	int error = 0;
379 	struct ng_mesg *msg;
380 	struct ngd_param_s * datap;
381 
382 	DBG;
383 
384 	SLIST_FOREACH(tmp,&sc->head,links) {
385 		if(tmp->ngddev == dev) {
386 			connection = tmp;
387 		}
388 	}
389 	if(connection == NULL) {
390 		printf("%s(): connection is still NULL, no dev found\n",__func__);
391 		return(-1);
392 	}
393 
394 	NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s),
395 			M_NOWAIT);
396 	if (msg == NULL) {
397 		printf("%s(): msg == NULL\n",__func__);
398 		goto nomsg;
399 	}
400 
401 	/* pass the ioctl data into the ->data area */
402 	datap = (struct ngd_param_s *)msg->data;
403 	datap->p = addr;
404 
405 	NG_SEND_MSG_HOOK(error, sc->node, msg, connection->active_hook, 0);
406 	if(error)
407 		printf("%s(): NG_SEND_MSG_HOOK error: %d\n",__func__,error);
408 
409 nomsg:
410 
411 	return(0);
412 }
413 #endif /* if 0 */
414 
415 /*
416  * This function is called when a read(2) is done to our device.
417  * We process one mbuf from queue.
418  */
419 static int
420 ngdread(struct cdev *dev, struct uio *uio, int flag)
421 {
422 	priv_p	priv = (priv_p )dev->si_drv1;
423 	struct mbuf *m;
424 	int len, error = 0;
425 
426 	DBG;
427 
428 	/* get an mbuf */
429 	do {
430 		IF_DEQUEUE(&priv->readq, m);
431 		if (m == NULL) {
432 			if (flag & IO_NDELAY)
433 				return (EWOULDBLOCK);
434 			mtx_lock(&priv->ngd_mtx);
435 			priv->flags |= NGDF_RWAIT;
436 			mtx_unlock(&priv->ngd_mtx);
437 			if ((error = tsleep(priv, PCATCH | (PZERO + 1),
438 			    "ngdread", 0)) != 0)
439 				return (error);
440 		}
441 	} while (m == NULL);
442 
443 	while (m && uio->uio_resid > 0 && error == 0) {
444 		len = MIN(uio->uio_resid, m->m_len);
445 		if (len != 0)
446 			error = uiomove(mtod(m, void *), len, uio);
447 		m = m_free(m);
448 	}
449 
450 	if (m)
451 		m_freem(m);
452 
453 	return (error);
454 }
455 
456 
457 /*
458  * This function is called when our device is written to.
459  * We read the data from userland into mbuf chain and pass it to the remote hook.
460  *
461  */
462 static int
463 ngdwrite(struct cdev *dev, struct uio *uio, int flag)
464 {
465 	priv_p	priv = (priv_p )dev->si_drv1;
466 	struct mbuf *m;
467 	int error = 0;
468 
469 	DBG;
470 
471 	if (uio->uio_resid == 0)
472 		return (0);
473 
474 	if (uio->uio_resid < 0 || uio->uio_resid > IP_MAXPACKET)
475 		return (EIO);
476 
477 	if ((m = m_uiotombuf(uio, M_DONTWAIT, 0)) == NULL)
478 		return (ENOBUFS);
479 
480 	NG_SEND_DATA_ONLY(error, priv->hook, m);
481 
482 	return (error);
483 }
484 
485 /*
486  * we are being polled/selected
487  * check if there is data available for read
488  */
489 static int
490 ngdpoll(struct cdev *dev, int events, struct thread *td)
491 {
492 	priv_p	priv = (priv_p )dev->si_drv1;
493 	int revents = 0;
494 
495 	if (events & (POLLIN | POLLRDNORM) &&
496 	    !IFQ_IS_EMPTY(&priv->readq))
497 		revents |= events & (POLLIN | POLLRDNORM);
498 
499 	return (revents);
500 }
501 
502 /******************************************************************************
503  *  Helper subroutines
504  ******************************************************************************/
505 
506 static int
507 get_free_unit()
508 {
509 	struct ngd_private *priv = NULL;
510 	int n = 0;
511 	int unit = -1;
512 
513 	DBG;
514 
515 	mtx_assert(&ng_device_mtx, MA_OWNED);
516 
517 	/* When there is no list yet, the first device unit is always 0. */
518 	if SLIST_EMPTY(&ngd_nodes)
519 		return(0);
520 
521 	/* Just do a brute force loop to find the first free unit that is
522 	 * smaller than MAX_NGD.
523 	 * Set MAX_NGD to a large value, doesn't impact performance.
524 	 */
525 	for(n = 0; n<MAX_NGD && unit == -1; n++) {
526 		SLIST_FOREACH(priv, &ngd_nodes, links) {
527 
528 			if(priv->unit == n) {
529 				unit = -1;
530 				break;
531 			}
532 			unit = n;
533 		}
534 	}
535 
536 	return (unit);
537 }
538