xref: /freebsd/sys/netgraph/ng_device.c (revision 6419bb52) 
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2002 Mark Santcroos <marks@ripe.net>
5  * Copyright (c) 2004-2005 Gleb Smirnoff <glebius@FreeBSD.org>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  *
27  * Netgraph "device" node
28  *
29  * This node presents a /dev/ngd%d device that interfaces to an other
30  * netgraph node.
31  *
32  * $FreeBSD$
33  *
34  */
35 
36 #if 0
37 #define	DBG do { printf("ng_device: %s\n", __func__ ); } while (0)
38 #else
39 #define	DBG do {} while (0)
40 #endif
41 
42 #include <sys/param.h>
43 #include <sys/conf.h>
44 #include <sys/ioccom.h>
45 #include <sys/kernel.h>
46 #include <sys/malloc.h>
47 #include <sys/mbuf.h>
48 #include <sys/poll.h>
49 #include <sys/proc.h>
50 #include <sys/epoch.h>
51 #include <sys/queue.h>
52 #include <sys/socket.h>
53 #include <sys/systm.h>
54 #include <sys/uio.h>
55 #include <sys/vnode.h>
56 
57 #include <net/if.h>
58 #include <net/if_var.h>
59 #include <netinet/in.h>
60 #include <netinet/in_systm.h>
61 #include <netinet/ip.h>
62 
63 #include <netgraph/ng_message.h>
64 #include <netgraph/netgraph.h>
65 #include <netgraph/ng_device.h>
66 
67 #define	ERROUT(x) do { error = (x); goto done; } while (0)
68 
69 /* Netgraph methods */
70 static int		ng_device_mod_event(module_t, int, void *);
71 static ng_constructor_t	ng_device_constructor;
72 static ng_rcvmsg_t	ng_device_rcvmsg;
73 static ng_shutdown_t	ng_device_shutdown;
74 static ng_newhook_t	ng_device_newhook;
75 static ng_rcvdata_t	ng_device_rcvdata;
76 static ng_disconnect_t	ng_device_disconnect;
77 
78 /* Netgraph type */
79 static struct ng_type ngd_typestruct = {
80 	.version =	NG_ABI_VERSION,
81 	.name =		NG_DEVICE_NODE_TYPE,
82 	.mod_event =	ng_device_mod_event,
83 	.constructor =	ng_device_constructor,
84 	.rcvmsg	=	ng_device_rcvmsg,
85 	.shutdown = 	ng_device_shutdown,
86 	.newhook =	ng_device_newhook,
87 	.rcvdata =	ng_device_rcvdata,
88 	.disconnect =	ng_device_disconnect,
89 };
90 NETGRAPH_INIT(device, &ngd_typestruct);
91 
92 /* per node data */
93 struct ngd_private {
94 	struct	ifqueue	readq;
95 	struct	ng_node	*node;
96 	struct	ng_hook	*hook;
97 	struct	cdev	*ngddev;
98 	struct	mtx	ngd_mtx;
99 	int 		unit;
100 	uint16_t	flags;
101 #define	NGDF_OPEN	0x0001
102 #define	NGDF_RWAIT	0x0002
103 };
104 typedef struct ngd_private *priv_p;
105 
106 /* unit number allocator entity */
107 static struct unrhdr *ngd_unit;
108 
109 /* Maximum number of NGD devices */
110 #define MAX_NGD	999
111 
112 static d_close_t ngdclose;
113 static d_open_t ngdopen;
114 static d_read_t ngdread;
115 static d_write_t ngdwrite;
116 #if 0
117 static d_ioctl_t ngdioctl;
118 #endif
119 static d_poll_t ngdpoll;
120 
121 static struct cdevsw ngd_cdevsw = {
122 	.d_version =	D_VERSION,
123 	.d_open =	ngdopen,
124 	.d_close =	ngdclose,
125 	.d_read =	ngdread,
126 	.d_write =	ngdwrite,
127 #if 0
128 	.d_ioctl =	ngdioctl,
129 #endif
130 	.d_poll =	ngdpoll,
131 	.d_name =	NG_DEVICE_DEVNAME,
132 };
133 
134 /******************************************************************************
135  *  Netgraph methods
136  ******************************************************************************/
137 
138 /*
139  * Handle loading and unloading for this node type.
140  */
141 static int
142 ng_device_mod_event(module_t mod, int event, void *data)
143 {
144 	int error = 0;
145 
146 	switch (event) {
147 	case MOD_LOAD:
148 		ngd_unit = new_unrhdr(0, MAX_NGD, NULL);
149 		break;
150 	case MOD_UNLOAD:
151 		delete_unrhdr(ngd_unit);
152 		break;
153 	default:
154 		error = EOPNOTSUPP;
155 		break;
156 	}
157 	return (error);
158 }
159 
160 /*
161  * create new node
162  */
163 static int
164 ng_device_constructor(node_p node)
165 {
166 	priv_p	priv;
167 
168 	DBG;
169 
170 	priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
171 
172 	/* Allocate unit number */
173 	priv->unit = alloc_unr(ngd_unit);
174 
175 	/* Initialize mutexes and queue */
176 	mtx_init(&priv->ngd_mtx, "ng_device", NULL, MTX_DEF);
177 	mtx_init(&priv->readq.ifq_mtx, "ng_device queue", NULL, MTX_DEF);
178 	IFQ_SET_MAXLEN(&priv->readq, ifqmaxlen);
179 
180 	/* Link everything together */
181 	NG_NODE_SET_PRIVATE(node, priv);
182 	priv->node = node;
183 
184 	priv->ngddev = make_dev(&ngd_cdevsw, priv->unit, UID_ROOT,
185 	    GID_WHEEL, 0600, NG_DEVICE_DEVNAME "%d", priv->unit);
186 	if(priv->ngddev == NULL) {
187 		printf("%s(): make_dev() failed\n",__func__);
188 		mtx_destroy(&priv->ngd_mtx);
189 		mtx_destroy(&priv->readq.ifq_mtx);
190 		free_unr(ngd_unit, priv->unit);
191 		free(priv, M_NETGRAPH);
192 		return(EINVAL);
193 	}
194 	/* XXX: race here? */
195 	priv->ngddev->si_drv1 = priv;
196 
197 	return(0);
198 }
199 
200 /*
201  * Process control message.
202  */
203 
204 static int
205 ng_device_rcvmsg(node_p node, item_p item, hook_p lasthook)
206 {
207 	const priv_p priv = NG_NODE_PRIVATE(node);
208 	struct ng_mesg *msg;
209 	struct ng_mesg *resp = NULL;
210 	const char *dn;
211 	int error = 0;
212 
213 	NGI_GET_MSG(item, msg);
214 
215 	if (msg->header.typecookie == NGM_DEVICE_COOKIE) {
216 		switch (msg->header.cmd) {
217 		case NGM_DEVICE_GET_DEVNAME:
218 			/* XXX: Fix when MAX_NGD us bigger */
219 			NG_MKRESPONSE(resp, msg,
220 			    strlen(NG_DEVICE_DEVNAME) + 4, M_NOWAIT);
221 
222 			if (resp == NULL)
223 				ERROUT(ENOMEM);
224 
225 			dn = devtoname(priv->ngddev);
226 			strlcpy((char *)resp->data, dn, strlen(dn) + 1);
227 			break;
228 
229 		default:
230 			error = EINVAL;
231 			break;
232 		}
233 	} else
234 		error = EINVAL;
235 
236 done:
237 	NG_RESPOND_MSG(error, node, item, resp);
238 	NG_FREE_MSG(msg);
239 	return (error);
240 }
241 
242 /*
243  * Accept incoming hook. We support only one hook per node.
244  */
245 static int
246 ng_device_newhook(node_p node, hook_p hook, const char *name)
247 {
248 	priv_p priv = NG_NODE_PRIVATE(node);
249 
250 	DBG;
251 
252 	/* We have only one hook per node */
253 	if (priv->hook != NULL)
254 		return (EISCONN);
255 
256 	priv->hook = hook;
257 
258 	return(0);
259 }
260 
261 /*
262  * Receive data from hook, write it to device.
263  */
264 static int
265 ng_device_rcvdata(hook_p hook, item_p item)
266 {
267 	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
268 	struct mbuf *m;
269 
270 	DBG;
271 
272 	NGI_GET_M(item, m);
273 	NG_FREE_ITEM(item);
274 
275 	IF_LOCK(&priv->readq);
276 	if (_IF_QFULL(&priv->readq)) {
277 		IF_UNLOCK(&priv->readq);
278 		NG_FREE_M(m);
279 		return (ENOBUFS);
280 	}
281 
282 	_IF_ENQUEUE(&priv->readq, m);
283 	IF_UNLOCK(&priv->readq);
284 	mtx_lock(&priv->ngd_mtx);
285 	if (priv->flags & NGDF_RWAIT) {
286 		priv->flags &= ~NGDF_RWAIT;
287 		wakeup(priv);
288 	}
289 	mtx_unlock(&priv->ngd_mtx);
290 
291 	return(0);
292 }
293 
294 /*
295  * Removal of the hook destroys the node.
296  */
297 static int
298 ng_device_disconnect(hook_p hook)
299 {
300 	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
301 
302 	DBG;
303 
304 	destroy_dev(priv->ngddev);
305 	mtx_destroy(&priv->ngd_mtx);
306 
307 	IF_DRAIN(&priv->readq);
308 	mtx_destroy(&(priv)->readq.ifq_mtx);
309 
310 	free_unr(ngd_unit, priv->unit);
311 
312 	free(priv, M_NETGRAPH);
313 
314 	ng_rmnode_self(NG_HOOK_NODE(hook));
315 
316 	return(0);
317 }
318 
319 /*
320  * Node shutdown. Everything is already done in disconnect method.
321  */
322 static int
323 ng_device_shutdown(node_p node)
324 {
325 	NG_NODE_UNREF(node);
326 	return (0);
327 }
328 
329 /******************************************************************************
330  *  Device methods
331  ******************************************************************************/
332 
333 /*
334  * the device is opened
335  */
336 static int
337 ngdopen(struct cdev *dev, int flag, int mode, struct thread *td)
338 {
339 	priv_p	priv = (priv_p )dev->si_drv1;
340 
341 	DBG;
342 
343 	mtx_lock(&priv->ngd_mtx);
344 	priv->flags |= NGDF_OPEN;
345 	mtx_unlock(&priv->ngd_mtx);
346 
347 	return(0);
348 }
349 
350 /*
351  * the device is closed
352  */
353 static int
354 ngdclose(struct cdev *dev, int flag, int mode, struct thread *td)
355 {
356 	priv_p	priv = (priv_p )dev->si_drv1;
357 
358 	DBG;
359 	mtx_lock(&priv->ngd_mtx);
360 	priv->flags &= ~NGDF_OPEN;
361 	mtx_unlock(&priv->ngd_mtx);
362 
363 	return(0);
364 }
365 
366 #if 0	/*
367 	 * The ioctl is transformed into netgraph control message.
368 	 * We do not process them, yet.
369 	 */
370 /*
371  * process ioctl
372  *
373  * they are translated into netgraph messages and passed on
374  *
375  */
376 static int
377 ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
378 {
379 	struct ngd_softc *sc = &ngd_softc;
380 	struct ngd_connection * connection = NULL;
381 	struct ngd_connection * tmp;
382 	int error = 0;
383 	struct ng_mesg *msg;
384 	struct ngd_param_s * datap;
385 
386 	DBG;
387 
388 	NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s),
389 			M_NOWAIT);
390 	if (msg == NULL) {
391 		printf("%s(): msg == NULL\n",__func__);
392 		goto nomsg;
393 	}
394 
395 	/* pass the ioctl data into the ->data area */
396 	datap = (struct ngd_param_s *)msg->data;
397 	datap->p = addr;
398 
399 	NG_SEND_MSG_HOOK(error, sc->node, msg, connection->active_hook, 0);
400 	if(error)
401 		printf("%s(): NG_SEND_MSG_HOOK error: %d\n",__func__,error);
402 
403 nomsg:
404 
405 	return(0);
406 }
407 #endif /* if 0 */
408 
409 /*
410  * This function is called when a read(2) is done to our device.
411  * We process one mbuf from queue.
412  */
413 static int
414 ngdread(struct cdev *dev, struct uio *uio, int flag)
415 {
416 	priv_p	priv = (priv_p )dev->si_drv1;
417 	struct mbuf *m;
418 	int len, error = 0;
419 
420 	DBG;
421 
422 	/* get an mbuf */
423 	do {
424 		IF_DEQUEUE(&priv->readq, m);
425 		if (m == NULL) {
426 			if (flag & IO_NDELAY)
427 				return (EWOULDBLOCK);
428 			mtx_lock(&priv->ngd_mtx);
429 			priv->flags |= NGDF_RWAIT;
430 			if ((error = msleep(priv, &priv->ngd_mtx,
431 			    PDROP | PCATCH | (PZERO + 1),
432 			    "ngdread", 0)) != 0)
433 				return (error);
434 		}
435 	} while (m == NULL);
436 
437 	while (m && uio->uio_resid > 0 && error == 0) {
438 		len = MIN(uio->uio_resid, m->m_len);
439 		if (len != 0)
440 			error = uiomove(mtod(m, void *), len, uio);
441 		m = m_free(m);
442 	}
443 
444 	if (m)
445 		m_freem(m);
446 
447 	return (error);
448 }
449 
450 
451 /*
452  * This function is called when our device is written to.
453  * We read the data from userland into mbuf chain and pass it to the remote hook.
454  *
455  */
456 static int
457 ngdwrite(struct cdev *dev, struct uio *uio, int flag)
458 {
459 	struct epoch_tracker et;
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_NOWAIT, 0, 0, M_PKTHDR)) == NULL)
473 		return (ENOBUFS);
474 
475 	NET_EPOCH_ENTER(et);
476 	NG_SEND_DATA_ONLY(error, priv->hook, m);
477 	NET_EPOCH_EXIT(et);
478 
479 	return (error);
480 }
481 
482 /*
483  * we are being polled/selected
484  * check if there is data available for read
485  */
486 static int
487 ngdpoll(struct cdev *dev, int events, struct thread *td)
488 {
489 	priv_p	priv = (priv_p )dev->si_drv1;
490 	int revents = 0;
491 
492 	if (events & (POLLIN | POLLRDNORM) &&
493 	    !IFQ_IS_EMPTY(&priv->readq))
494 		revents |= events & (POLLIN | POLLRDNORM);
495 
496 	return (revents);
497 }
498