xref: /freebsd/sys/netgraph/ng_device.c (revision 535af610) 
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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/syslog.h>
54 #include <sys/systm.h>
55 #include <sys/uio.h>
56 #include <sys/vnode.h>
57 
58 #include <net/ethernet.h>
59 #include <net/if.h>
60 #include <net/if_var.h>
61 #include <netinet/in.h>
62 #include <netinet/in_systm.h>
63 #include <netinet/ip.h>
64 
65 #include <netgraph/ng_message.h>
66 #include <netgraph/netgraph.h>
67 #include <netgraph/ng_device.h>
68 #include <netgraph/ng_parse.h>
69 
70 #define	ERROUT(x) do { error = (x); goto done; } while (0)
71 
72 /* Netgraph methods */
73 static int		ng_device_mod_event(module_t, int, void *);
74 static ng_constructor_t	ng_device_constructor;
75 static ng_rcvmsg_t	ng_device_rcvmsg;
76 static ng_shutdown_t	ng_device_shutdown;
77 static ng_newhook_t	ng_device_newhook;
78 static ng_rcvdata_t	ng_device_rcvdata;
79 static ng_disconnect_t	ng_device_disconnect;
80 
81 /* List of commands and how to convert arguments to/from ASCII. */
82 static const struct ng_cmdlist ng_device_cmds[] = {
83 	{
84 	  NGM_DEVICE_COOKIE,
85 	  NGM_DEVICE_GET_DEVNAME,
86 	  "getdevname",
87 	  NULL,
88 	  &ng_parse_string_type
89 	},
90 	{
91 	  NGM_DEVICE_COOKIE,
92 	  NGM_DEVICE_ETHERALIGN,
93 	  "etheralign",
94 	  NULL,
95 	  NULL
96 	},
97 	{ 0 }
98 };
99 
100 /* Netgraph type */
101 static struct ng_type ngd_typestruct = {
102 	.version =	NG_ABI_VERSION,
103 	.name =		NG_DEVICE_NODE_TYPE,
104 	.mod_event =	ng_device_mod_event,
105 	.constructor =	ng_device_constructor,
106 	.rcvmsg	=	ng_device_rcvmsg,
107 	.shutdown = 	ng_device_shutdown,
108 	.newhook =	ng_device_newhook,
109 	.rcvdata =	ng_device_rcvdata,
110 	.disconnect =	ng_device_disconnect,
111 	.cmdlist =	ng_device_cmds,
112 };
113 NETGRAPH_INIT(device, &ngd_typestruct);
114 
115 /* per node data */
116 struct ngd_private {
117 	struct	ifqueue	readq;
118 	struct	ng_node	*node;
119 	struct	ng_hook	*hook;
120 	struct	cdev	*ngddev;
121 	struct	mtx	ngd_mtx;
122 	int 		unit;
123 	int		ether_align;
124 	uint16_t	flags;
125 #define	NGDF_OPEN	0x0001
126 #define	NGDF_RWAIT	0x0002
127 };
128 typedef struct ngd_private *priv_p;
129 
130 /* unit number allocator entity */
131 static struct unrhdr *ngd_unit;
132 
133 /* Maximum number of NGD devices */
134 #define MAX_NGD	999
135 
136 static d_close_t ngdclose;
137 static d_open_t ngdopen;
138 static d_read_t ngdread;
139 static d_write_t ngdwrite;
140 #if 0
141 static d_ioctl_t ngdioctl;
142 #endif
143 static d_poll_t ngdpoll;
144 
145 static struct cdevsw ngd_cdevsw = {
146 	.d_version =	D_VERSION,
147 	.d_open =	ngdopen,
148 	.d_close =	ngdclose,
149 	.d_read =	ngdread,
150 	.d_write =	ngdwrite,
151 #if 0
152 	.d_ioctl =	ngdioctl,
153 #endif
154 	.d_poll =	ngdpoll,
155 	.d_name =	NG_DEVICE_DEVNAME,
156 };
157 
158 /******************************************************************************
159  *  Netgraph methods
160  ******************************************************************************/
161 
162 /*
163  * Handle loading and unloading for this node type.
164  */
165 static int
166 ng_device_mod_event(module_t mod, int event, void *data)
167 {
168 	int error = 0;
169 
170 	switch (event) {
171 	case MOD_LOAD:
172 		ngd_unit = new_unrhdr(0, MAX_NGD, NULL);
173 		break;
174 	case MOD_UNLOAD:
175 		delete_unrhdr(ngd_unit);
176 		break;
177 	default:
178 		error = EOPNOTSUPP;
179 		break;
180 	}
181 	return (error);
182 }
183 
184 /*
185  * create new node
186  */
187 static int
188 ng_device_constructor(node_p node)
189 {
190 	priv_p	priv;
191 
192 	DBG;
193 
194 	priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
195 
196 	/* Allocate unit number */
197 	priv->unit = alloc_unr(ngd_unit);
198 
199 	/* Initialize mutexes and queue */
200 	mtx_init(&priv->ngd_mtx, "ng_device", NULL, MTX_DEF);
201 	mtx_init(&priv->readq.ifq_mtx, "ng_device queue", NULL, MTX_DEF);
202 	IFQ_SET_MAXLEN(&priv->readq, ifqmaxlen);
203 
204 	/* Link everything together */
205 	NG_NODE_SET_PRIVATE(node, priv);
206 	priv->node = node;
207 
208 	priv->ngddev = make_dev(&ngd_cdevsw, priv->unit, UID_ROOT,
209 	    GID_WHEEL, 0600, NG_DEVICE_DEVNAME "%d", priv->unit);
210 	if(priv->ngddev == NULL) {
211 		printf("%s(): make_dev() failed\n",__func__);
212 		mtx_destroy(&priv->ngd_mtx);
213 		mtx_destroy(&priv->readq.ifq_mtx);
214 		free_unr(ngd_unit, priv->unit);
215 		free(priv, M_NETGRAPH);
216 		return(EINVAL);
217 	}
218 	/* XXX: race here? */
219 	priv->ngddev->si_drv1 = priv;
220 
221 	/* Give this node the same name as the device (if possible). */
222 	if (ng_name_node(node, devtoname(priv->ngddev)) != 0)
223 		log(LOG_WARNING, "%s: can't acquire netgraph name\n",
224 		    devtoname(priv->ngddev));
225 
226 	return(0);
227 }
228 
229 /*
230  * Process control message.
231  */
232 
233 static int
234 ng_device_rcvmsg(node_p node, item_p item, hook_p lasthook)
235 {
236 	const priv_p priv = NG_NODE_PRIVATE(node);
237 	struct ng_mesg *msg;
238 	struct ng_mesg *resp = NULL;
239 	const char *dn;
240 	int error = 0;
241 
242 	NGI_GET_MSG(item, msg);
243 
244 	if (msg->header.typecookie == NGM_DEVICE_COOKIE) {
245 		switch (msg->header.cmd) {
246 		case NGM_DEVICE_GET_DEVNAME:
247 			/* XXX: Fix when MAX_NGD us bigger */
248 			NG_MKRESPONSE(resp, msg,
249 			    strlen(NG_DEVICE_DEVNAME) + 4, M_NOWAIT);
250 
251 			if (resp == NULL)
252 				ERROUT(ENOMEM);
253 
254 			dn = devtoname(priv->ngddev);
255 			strlcpy((char *)resp->data, dn, strlen(dn) + 1);
256 			break;
257 
258 		case NGM_DEVICE_ETHERALIGN:
259 			/* Use ETHER_ALIGN on arches that require it. */
260 #ifndef __NO_STRICT_ALIGNMENT
261 			priv->ether_align = ETHER_ALIGN;
262 #endif
263 			break;
264 
265 		default:
266 			error = EINVAL;
267 			break;
268 		}
269 	} else
270 		error = EINVAL;
271 
272 done:
273 	NG_RESPOND_MSG(error, node, item, resp);
274 	NG_FREE_MSG(msg);
275 	return (error);
276 }
277 
278 /*
279  * Accept incoming hook. We support only one hook per node.
280  */
281 static int
282 ng_device_newhook(node_p node, hook_p hook, const char *name)
283 {
284 	priv_p priv = NG_NODE_PRIVATE(node);
285 
286 	DBG;
287 
288 	/* We have only one hook per node */
289 	if (priv->hook != NULL)
290 		return (EISCONN);
291 
292 	priv->hook = hook;
293 
294 	return(0);
295 }
296 
297 /*
298  * Receive data from hook, write it to device.
299  */
300 static int
301 ng_device_rcvdata(hook_p hook, item_p item)
302 {
303 	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
304 	struct mbuf *m;
305 
306 	DBG;
307 
308 	NGI_GET_M(item, m);
309 	NG_FREE_ITEM(item);
310 
311 	IF_LOCK(&priv->readq);
312 	if (_IF_QFULL(&priv->readq)) {
313 		IF_UNLOCK(&priv->readq);
314 		NG_FREE_M(m);
315 		return (ENOBUFS);
316 	}
317 
318 	_IF_ENQUEUE(&priv->readq, m);
319 	IF_UNLOCK(&priv->readq);
320 	mtx_lock(&priv->ngd_mtx);
321 	if (priv->flags & NGDF_RWAIT) {
322 		priv->flags &= ~NGDF_RWAIT;
323 		wakeup(priv);
324 	}
325 	mtx_unlock(&priv->ngd_mtx);
326 
327 	return(0);
328 }
329 
330 /*
331  * Removal of the hook destroys the node.
332  */
333 static int
334 ng_device_disconnect(hook_p hook)
335 {
336 	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
337 
338 	DBG;
339 
340 	destroy_dev(priv->ngddev);
341 	mtx_destroy(&priv->ngd_mtx);
342 
343 	IF_DRAIN(&priv->readq);
344 	mtx_destroy(&(priv)->readq.ifq_mtx);
345 
346 	free_unr(ngd_unit, priv->unit);
347 
348 	free(priv, M_NETGRAPH);
349 
350 	ng_rmnode_self(NG_HOOK_NODE(hook));
351 
352 	return(0);
353 }
354 
355 /*
356  * Node shutdown. Everything is already done in disconnect method.
357  */
358 static int
359 ng_device_shutdown(node_p node)
360 {
361 	NG_NODE_UNREF(node);
362 	return (0);
363 }
364 
365 /******************************************************************************
366  *  Device methods
367  ******************************************************************************/
368 
369 /*
370  * the device is opened
371  */
372 static int
373 ngdopen(struct cdev *dev, int flag, int mode, struct thread *td)
374 {
375 	priv_p	priv = (priv_p )dev->si_drv1;
376 
377 	DBG;
378 
379 	mtx_lock(&priv->ngd_mtx);
380 	priv->flags |= NGDF_OPEN;
381 	mtx_unlock(&priv->ngd_mtx);
382 
383 	return(0);
384 }
385 
386 /*
387  * the device is closed
388  */
389 static int
390 ngdclose(struct cdev *dev, int flag, int mode, struct thread *td)
391 {
392 	priv_p	priv = (priv_p )dev->si_drv1;
393 
394 	DBG;
395 	mtx_lock(&priv->ngd_mtx);
396 	priv->flags &= ~NGDF_OPEN;
397 	mtx_unlock(&priv->ngd_mtx);
398 
399 	return(0);
400 }
401 
402 #if 0	/*
403 	 * The ioctl is transformed into netgraph control message.
404 	 * We do not process them, yet.
405 	 */
406 /*
407  * process ioctl
408  *
409  * they are translated into netgraph messages and passed on
410  *
411  */
412 static int
413 ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
414 {
415 	struct ngd_softc *sc = &ngd_softc;
416 	struct ngd_connection * connection = NULL;
417 	struct ngd_connection * tmp;
418 	int error = 0;
419 	struct ng_mesg *msg;
420 	struct ngd_param_s * datap;
421 
422 	DBG;
423 
424 	NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s),
425 			M_NOWAIT);
426 	if (msg == NULL) {
427 		printf("%s(): msg == NULL\n",__func__);
428 		goto nomsg;
429 	}
430 
431 	/* pass the ioctl data into the ->data area */
432 	datap = (struct ngd_param_s *)msg->data;
433 	datap->p = addr;
434 
435 	NG_SEND_MSG_HOOK(error, sc->node, msg, connection->active_hook, 0);
436 	if(error)
437 		printf("%s(): NG_SEND_MSG_HOOK error: %d\n",__func__,error);
438 
439 nomsg:
440 
441 	return(0);
442 }
443 #endif /* if 0 */
444 
445 /*
446  * This function is called when a read(2) is done to our device.
447  * We process one mbuf from queue.
448  */
449 static int
450 ngdread(struct cdev *dev, struct uio *uio, int flag)
451 {
452 	priv_p	priv = (priv_p )dev->si_drv1;
453 	struct mbuf *m;
454 	int len, error = 0;
455 
456 	DBG;
457 
458 	/* get an mbuf */
459 	do {
460 		IF_DEQUEUE(&priv->readq, m);
461 		if (m == NULL) {
462 			if (flag & IO_NDELAY)
463 				return (EWOULDBLOCK);
464 			mtx_lock(&priv->ngd_mtx);
465 			priv->flags |= NGDF_RWAIT;
466 			if ((error = msleep(priv, &priv->ngd_mtx,
467 			    PDROP | PCATCH | (PZERO + 1),
468 			    "ngdread", 0)) != 0)
469 				return (error);
470 		}
471 	} while (m == NULL);
472 
473 	while (m && uio->uio_resid > 0 && error == 0) {
474 		len = MIN(uio->uio_resid, m->m_len);
475 		if (len != 0)
476 			error = uiomove(mtod(m, void *), len, uio);
477 		m = m_free(m);
478 	}
479 
480 	if (m)
481 		m_freem(m);
482 
483 	return (error);
484 }
485 
486 /*
487  * This function is called when our device is written to.
488  * We read the data from userland into mbuf chain and pass it to the remote hook.
489  *
490  */
491 static int
492 ngdwrite(struct cdev *dev, struct uio *uio, int flag)
493 {
494 	struct epoch_tracker et;
495 	priv_p	priv = (priv_p )dev->si_drv1;
496 	struct mbuf *m;
497 	int error = 0;
498 
499 	DBG;
500 
501 	if (uio->uio_resid == 0)
502 		return (0);
503 
504 	if (uio->uio_resid < 0 || uio->uio_resid > IP_MAXPACKET)
505 		return (EIO);
506 
507 	m = m_uiotombuf(uio, M_NOWAIT, 0, priv->ether_align, M_PKTHDR);
508 	if (m == NULL)
509 		return (ENOBUFS);
510 
511 	NET_EPOCH_ENTER(et);
512 	NG_SEND_DATA_ONLY(error, priv->hook, m);
513 	NET_EPOCH_EXIT(et);
514 
515 	return (error);
516 }
517 
518 /*
519  * we are being polled/selected
520  * check if there is data available for read
521  */
522 static int
523 ngdpoll(struct cdev *dev, int events, struct thread *td)
524 {
525 	priv_p	priv = (priv_p )dev->si_drv1;
526 	int revents = 0;
527 
528 	if (events & (POLLIN | POLLRDNORM) &&
529 	    !IFQ_IS_EMPTY(&priv->readq))
530 		revents |= events & (POLLIN | POLLRDNORM);
531 
532 	return (revents);
533 }
534