xref: /freebsd/sys/netgraph/ng_device.c (revision 71651a2743acfa3756ab1e7c3983e6861c6fada1) 
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 int		ng_device_mod_event(module_t, int, void *);
67 static ng_constructor_t	ng_device_constructor;
68 static ng_rcvmsg_t	ng_device_rcvmsg;
69 static ng_shutdown_t	ng_device_shutdown;
70 static ng_newhook_t	ng_device_newhook;
71 static ng_rcvdata_t	ng_device_rcvdata;
72 static ng_disconnect_t	ng_device_disconnect;
73 
74 /* Netgraph type */
75 static struct ng_type ngd_typestruct = {
76 	.version =	NG_ABI_VERSION,
77 	.name =		NG_DEVICE_NODE_TYPE,
78 	.mod_event =	ng_device_mod_event,
79 	.constructor =	ng_device_constructor,
80 	.rcvmsg	=	ng_device_rcvmsg,
81 	.shutdown = 	ng_device_shutdown,
82 	.newhook =	ng_device_newhook,
83 	.rcvdata =	ng_device_rcvdata,
84 	.disconnect =	ng_device_disconnect,
85 };
86 NETGRAPH_INIT(device, &ngd_typestruct);
87 
88 /* per node data */
89 struct ngd_private {
90 	struct	ifqueue	readq;
91 	SLIST_ENTRY(ngd_private) links;
92 	struct	ng_node	*node;
93 	struct	ng_hook	*hook;
94 	struct	cdev	*ngddev;
95 	struct	mtx	ngd_mtx;
96 	int 		unit;
97 	uint16_t	flags;
98 #define	NGDF_OPEN	0x0001
99 #define	NGDF_RWAIT	0x0002
100 };
101 typedef struct ngd_private *priv_p;
102 
103 /* List of all active nodes and mutex to protect it */
104 static SLIST_HEAD(, ngd_private) ngd_nodes = SLIST_HEAD_INITIALIZER(ngd_nodes);
105 static struct mtx	ng_device_mtx;
106 
107 /* Maximum number of NGD devices */
108 #define MAX_NGD	25	/* should be more than enough for now */
109 
110 static d_close_t ngdclose;
111 static d_open_t ngdopen;
112 static d_read_t ngdread;
113 static d_write_t ngdwrite;
114 #if 0
115 static d_ioctl_t ngdioctl;
116 #endif
117 static d_poll_t ngdpoll;
118 
119 static struct cdevsw ngd_cdevsw = {
120 	.d_version =	D_VERSION,
121 	.d_open =	ngdopen,
122 	.d_close =	ngdclose,
123 	.d_read =	ngdread,
124 	.d_write =	ngdwrite,
125 #if 0
126 	.d_ioctl =	ngdioctl,
127 #endif
128 	.d_poll =	ngdpoll,
129 	.d_name =	NG_DEVICE_DEVNAME,
130 };
131 
132 /* Helper functions */
133 static int get_free_unit(void);
134 
135 /******************************************************************************
136  *  Netgraph methods
137  ******************************************************************************/
138 
139 /*
140  * create new node
141  */
142 static int
143 ng_device_constructor(node_p node)
144 {
145 	priv_p	priv;
146 
147 	DBG;
148 
149 	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
150 	if (priv == NULL)
151 		return (ENOMEM);
152 
153 	mtx_lock(&ng_device_mtx);
154 	priv->unit = get_free_unit();
155 	if(priv->unit < 0) {
156 		printf("%s: No free unit found by get_free_unit(), "
157 				"increase MAX_NGD\n",__func__);
158 		mtx_unlock(&ng_device_mtx);
159 		FREE(priv, M_NETGRAPH);
160 		return(EINVAL);
161 	}
162 	SLIST_INSERT_HEAD(&ngd_nodes, priv, links);
163 	mtx_unlock(&ng_device_mtx);
164 
165 	/* Initialize mutexes and queue */
166 	mtx_init(&priv->ngd_mtx, "ng_device", NULL, MTX_DEF);
167 	mtx_init(&priv->readq.ifq_mtx, "ng_device queue", NULL, MTX_DEF);
168 	IFQ_SET_MAXLEN(&priv->readq, ifqmaxlen);
169 
170 	/* Link everything together */
171 	NG_NODE_SET_PRIVATE(node, priv);
172 	priv->node = node;
173 
174 	priv->ngddev = make_dev(&ngd_cdevsw, unit2minor(priv->unit), UID_ROOT,
175 	    GID_WHEEL, 0600, NG_DEVICE_DEVNAME "%d", priv->unit);
176 	if(priv->ngddev == NULL) {
177 		printf("%s(): make_dev() failed\n",__func__);
178 		mtx_destroy(&priv->ngd_mtx);
179 		mtx_destroy(&priv->readq.ifq_mtx);
180 		FREE(priv, M_NETGRAPH);
181 		return(EINVAL);
182 	}
183 	/* XXX: race here? */
184 	priv->ngddev->si_drv1 = priv;
185 
186 	return(0);
187 }
188 
189 /*
190  * Process control message.
191  */
192 
193 static int
194 ng_device_rcvmsg(node_p node, item_p item, hook_p lasthook)
195 {
196 	const priv_p priv = NG_NODE_PRIVATE(node);
197 	struct ng_mesg *msg;
198 	struct ng_mesg *resp = NULL;
199 	int error = 0;
200 
201 	NGI_GET_MSG(item, msg);
202 
203 	if (msg->header.typecookie == NGM_DEVICE_COOKIE) {
204 		switch (msg->header.cmd) {
205 		case NGM_DEVICE_GET_DEVNAME:
206 			/* XXX: Fix when NGD_MAX us bigger */
207 			NG_MKRESPONSE(resp, msg,
208 			    strlen(NG_DEVICE_DEVNAME) + 3, M_NOWAIT);
209 
210 			if (resp == NULL)
211 				ERROUT(ENOMEM);
212 
213 			strlcpy((char *)resp->data, priv->ngddev->si_name,
214 			    strlen(priv->ngddev->si_name) + 1);
215 			break;
216 
217 		default:
218 			error = EINVAL;
219 			break;
220 		}
221 	} else
222 		error = EINVAL;
223 
224 done:
225 	NG_RESPOND_MSG(error, node, item, resp);
226 	NG_FREE_MSG(msg);
227 	return (error);
228 }
229 
230 /*
231  * Accept incoming hook. We support only one hook per node.
232  */
233 static int
234 ng_device_newhook(node_p node, hook_p hook, const char *name)
235 {
236 	priv_p priv = NG_NODE_PRIVATE(node);
237 
238 	DBG;
239 
240 	/* We have only one hook per node */
241 	if (priv->hook != NULL)
242 		return (EISCONN);
243 
244 	priv->hook = hook;
245 
246 	return(0);
247 }
248 
249 /*
250  * Receive data from hook, write it to device.
251  */
252 static int
253 ng_device_rcvdata(hook_p hook, item_p item)
254 {
255 	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
256 	struct mbuf *m;
257 
258 	DBG;
259 
260 	NGI_GET_M(item, m);
261 	NG_FREE_ITEM(item);
262 
263 	IF_LOCK(&priv->readq);
264 	if (_IF_QFULL(&priv->readq)) {
265 		_IF_DROP(&priv->readq);
266 		IF_UNLOCK(&priv->readq);
267 		NG_FREE_M(m);
268 		return (ENOBUFS);
269 	}
270 
271 	_IF_ENQUEUE(&priv->readq, m);
272 	IF_UNLOCK(&priv->readq);
273 	mtx_lock(&priv->ngd_mtx);
274 	if (priv->flags & NGDF_RWAIT) {
275 		priv->flags &= ~NGDF_RWAIT;
276 		wakeup(priv);
277 	}
278 	mtx_unlock(&priv->ngd_mtx);
279 
280 	return(0);
281 }
282 
283 /*
284  * Removal of the hook destroys the node.
285  */
286 static int
287 ng_device_disconnect(hook_p hook)
288 {
289 	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
290 
291 	DBG;
292 
293 	destroy_dev(priv->ngddev);
294 	mtx_destroy(&priv->ngd_mtx);
295 
296 	mtx_lock(&ng_device_mtx);
297 	SLIST_REMOVE(&ngd_nodes, priv, ngd_private, links);
298 	mtx_unlock(&ng_device_mtx);
299 
300 	IF_DRAIN(&priv->readq);
301 	mtx_destroy(&(priv)->readq.ifq_mtx);
302 
303 	FREE(priv, M_NETGRAPH);
304 
305 	ng_rmnode_self(NG_HOOK_NODE(hook));
306 
307 	return(0);
308 }
309 
310 /*
311  * Node shutdown. Everything is already done in disconnect method.
312  */
313 static int
314 ng_device_shutdown(node_p node)
315 {
316 	NG_NODE_UNREF(node);
317 	return (0);
318 }
319 
320 /******************************************************************************
321  *  Device methods
322  ******************************************************************************/
323 
324 /*
325  * the device is opened
326  */
327 static int
328 ngdopen(struct cdev *dev, int flag, int mode, struct thread *td)
329 {
330 	priv_p	priv = (priv_p )dev->si_drv1;
331 
332 	DBG;
333 
334 	mtx_lock(&priv->ngd_mtx);
335 	priv->flags |= NGDF_OPEN;
336 	mtx_unlock(&priv->ngd_mtx);
337 
338 	return(0);
339 }
340 
341 /*
342  * the device is closed
343  */
344 static int
345 ngdclose(struct cdev *dev, int flag, int mode, struct thread *td)
346 {
347 	priv_p	priv = (priv_p )dev->si_drv1;
348 
349 	DBG;
350 	mtx_lock(&priv->ngd_mtx);
351 	priv->flags &= ~NGDF_OPEN;
352 	mtx_unlock(&priv->ngd_mtx);
353 
354 	return(0);
355 }
356 
357 #if 0	/*
358 	 * The ioctl is transformed into netgraph control message.
359 	 * We do not process them, yet.
360 	 */
361 /*
362  * process ioctl
363  *
364  * they are translated into netgraph messages and passed on
365  *
366  */
367 static int
368 ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
369 {
370 	struct ngd_softc *sc = &ngd_softc;
371 	struct ngd_connection * connection = NULL;
372 	struct ngd_connection * tmp;
373 	int error = 0;
374 	struct ng_mesg *msg;
375 	struct ngd_param_s * datap;
376 
377 	DBG;
378 
379 	SLIST_FOREACH(tmp,&sc->head,links) {
380 		if(tmp->ngddev == dev) {
381 			connection = tmp;
382 		}
383 	}
384 	if(connection == NULL) {
385 		printf("%s(): connection is still NULL, no dev found\n",__func__);
386 		return(-1);
387 	}
388 
389 	NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s),
390 			M_NOWAIT);
391 	if (msg == NULL) {
392 		printf("%s(): msg == NULL\n",__func__);
393 		goto nomsg;
394 	}
395 
396 	/* pass the ioctl data into the ->data area */
397 	datap = (struct ngd_param_s *)msg->data;
398 	datap->p = addr;
399 
400 	NG_SEND_MSG_HOOK(error, sc->node, msg, connection->active_hook, 0);
401 	if(error)
402 		printf("%s(): NG_SEND_MSG_HOOK error: %d\n",__func__,error);
403 
404 nomsg:
405 
406 	return(0);
407 }
408 #endif /* if 0 */
409 
410 /*
411  * This function is called when a read(2) is done to our device.
412  * We process one mbuf from queue.
413  */
414 static int
415 ngdread(struct cdev *dev, struct uio *uio, int flag)
416 {
417 	priv_p	priv = (priv_p )dev->si_drv1;
418 	struct mbuf *m;
419 	int len, error = 0;
420 
421 	DBG;
422 
423 	/* get an mbuf */
424 	do {
425 		IF_DEQUEUE(&priv->readq, m);
426 		if (m == NULL) {
427 			if (flag & IO_NDELAY)
428 				return (EWOULDBLOCK);
429 			mtx_lock(&priv->ngd_mtx);
430 			priv->flags |= NGDF_RWAIT;
431 			if ((error = msleep(priv, &priv->ngd_mtx,
432 			    PDROP | PCATCH | (PZERO + 1),
433 			    "ngdread", 0)) != 0)
434 				return (error);
435 		}
436 	} while (m == NULL);
437 
438 	while (m && uio->uio_resid > 0 && error == 0) {
439 		len = MIN(uio->uio_resid, m->m_len);
440 		if (len != 0)
441 			error = uiomove(mtod(m, void *), len, uio);
442 		m = m_free(m);
443 	}
444 
445 	if (m)
446 		m_freem(m);
447 
448 	return (error);
449 }
450 
451 
452 /*
453  * This function is called when our device is written to.
454  * We read the data from userland into mbuf chain and pass it to the remote hook.
455  *
456  */
457 static int
458 ngdwrite(struct cdev *dev, struct uio *uio, int flag)
459 {
460 	priv_p	priv = (priv_p )dev->si_drv1;
461 	struct mbuf *m;
462 	int error = 0;
463 
464 	DBG;
465 
466 	if (uio->uio_resid == 0)
467 		return (0);
468 
469 	if (uio->uio_resid < 0 || uio->uio_resid > IP_MAXPACKET)
470 		return (EIO);
471 
472 	if ((m = m_uiotombuf(uio, M_DONTWAIT, 0)) == NULL)
473 		return (ENOBUFS);
474 
475 	NG_SEND_DATA_ONLY(error, priv->hook, m);
476 
477 	return (error);
478 }
479 
480 /*
481  * we are being polled/selected
482  * check if there is data available for read
483  */
484 static int
485 ngdpoll(struct cdev *dev, int events, struct thread *td)
486 {
487 	priv_p	priv = (priv_p )dev->si_drv1;
488 	int revents = 0;
489 
490 	if (events & (POLLIN | POLLRDNORM) &&
491 	    !IFQ_IS_EMPTY(&priv->readq))
492 		revents |= events & (POLLIN | POLLRDNORM);
493 
494 	return (revents);
495 }
496 
497 /******************************************************************************
498  *  Helper subroutines
499  ******************************************************************************/
500 
501 static int
502 get_free_unit()
503 {
504 	struct ngd_private *priv = NULL;
505 	int n = 0;
506 	int unit = -1;
507 
508 	DBG;
509 
510 	mtx_assert(&ng_device_mtx, MA_OWNED);
511 
512 	/* When there is no list yet, the first device unit is always 0. */
513 	if SLIST_EMPTY(&ngd_nodes)
514 		return(0);
515 
516 	/* Just do a brute force loop to find the first free unit that is
517 	 * smaller than MAX_NGD.
518 	 * Set MAX_NGD to a large value, doesn't impact performance.
519 	 */
520 	for(n = 0; n<MAX_NGD && unit == -1; n++) {
521 		SLIST_FOREACH(priv, &ngd_nodes, links) {
522 
523 			if(priv->unit == n) {
524 				unit = -1;
525 				break;
526 			}
527 			unit = n;
528 		}
529 	}
530 
531 	return (unit);
532 }
533 
534 /*
535  * Handle loading and unloading for this node type.
536  */
537 static int
538 ng_device_mod_event(module_t mod, int event, void *data)
539 {
540 	int error = 0;
541 
542 	switch (event) {
543 	case MOD_LOAD:
544 		mtx_init(&ng_device_mtx, "ng_device global", NULL, MTX_DEF);
545 		break;
546 	case MOD_UNLOAD:
547 		mtx_destroy(&ng_device_mtx);
548 		break;
549 	default:
550 		error = EOPNOTSUPP;
551 		break;
552 	}
553 	return (error);
554 }
555