ng_device.c revision 141341 
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: head/sys/netgraph/ng_device.c 141341 2005-02-05 08:28:36Z ru $
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 */
66static int		ng_device_mod_event(module_t, int, void *);
67static ng_constructor_t	ng_device_constructor;
68static ng_rcvmsg_t	ng_device_rcvmsg;
69static ng_shutdown_t	ng_device_shutdown;
70static ng_newhook_t	ng_device_newhook;
71static ng_rcvdata_t	ng_device_rcvdata;
72static ng_disconnect_t	ng_device_disconnect;
73
74/* Netgraph type */
75static 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};
86NETGRAPH_INIT(device, &ngd_typestruct);
87
88/* per node data */
89struct 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};
101typedef struct ngd_private *priv_p;
102
103/* List of all active nodes and mutex to protect it */
104static SLIST_HEAD(, ngd_private) ngd_nodes = SLIST_HEAD_INITIALIZER(ngd_nodes);
105static 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
110static d_close_t ngdclose;
111static d_open_t ngdopen;
112static d_read_t ngdread;
113static d_write_t ngdwrite;
114#if 0
115static d_ioctl_t ngdioctl;
116#endif
117static d_poll_t ngdpoll;
118
119static 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 */
133static int get_free_unit(void);
134
135/******************************************************************************
136 *  Netgraph methods
137 ******************************************************************************/
138
139/*
140 * create new node
141 */
142static int
143ng_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_init(&priv->ngd_mtx, "ng_device", NULL, MTX_DEF);
154	mtx_lock(&priv->ngd_mtx);
155
156	mtx_lock(&ng_device_mtx);
157
158	priv->unit = get_free_unit();
159	if(priv->unit < 0) {
160		printf("%s: No free unit found by get_free_unit(), "
161				"increase MAX_NGD\n",__func__);
162		mtx_unlock(&ng_device_mtx);
163		mtx_destroy(&priv->ngd_mtx);
164		FREE(priv, M_NETGRAPH);
165		return(EINVAL);
166	}
167
168	priv->ngddev = make_dev(&ngd_cdevsw, unit2minor(priv->unit), UID_ROOT,
169	    GID_WHEEL, 0600, NG_DEVICE_DEVNAME "%d", priv->unit);
170	if(priv->ngddev == NULL) {
171		printf("%s(): make_dev() failed\n",__func__);
172		mtx_unlock(&ng_device_mtx);
173		mtx_destroy(&priv->ngd_mtx);
174		FREE(priv, M_NETGRAPH);
175		return(EINVAL);
176	}
177
178	SLIST_INSERT_HEAD(&ngd_nodes, priv, links);
179
180	mtx_unlock(&ng_device_mtx);
181
182	mtx_init(&priv->readq.ifq_mtx, "ng_device queue", NULL, MTX_DEF);
183	IFQ_SET_MAXLEN(&priv->readq, ifqmaxlen);
184
185	/* Link everything together */
186	NG_NODE_SET_PRIVATE(node, priv);
187	priv->node = node;
188	priv->ngddev->si_drv1 = priv;
189
190	mtx_unlock(&priv->ngd_mtx);
191
192	return(0);
193}
194
195/*
196 * Process control message.
197 */
198
199static int
200ng_device_rcvmsg(node_p node, item_p item, hook_p lasthook)
201{
202	const priv_p priv = NG_NODE_PRIVATE(node);
203	struct ng_mesg *msg;
204	struct ng_mesg *resp = NULL;
205	int error = 0;
206
207	NGI_GET_MSG(item, msg);
208
209	if (msg->header.typecookie == NGM_DEVICE_COOKIE) {
210		switch (msg->header.cmd) {
211		case NGM_DEVICE_GET_DEVNAME:
212			/* XXX: Fix when NGD_MAX us bigger */
213			NG_MKRESPONSE(resp, msg,
214			    strlen(NG_DEVICE_DEVNAME) + 3, M_NOWAIT);
215
216			if (resp == NULL)
217				ERROUT(ENOMEM);
218
219			strlcpy((char *)resp->data, priv->ngddev->si_name,
220			    strlen(priv->ngddev->si_name) + 1);
221			break;
222
223		default:
224			error = EINVAL;
225			break;
226		}
227	} else
228		error = EINVAL;
229
230done:
231	NG_RESPOND_MSG(error, node, item, resp);
232	NG_FREE_MSG(msg);
233	return (error);
234}
235
236/*
237 * Accept incoming hook. We support only one hook per node.
238 */
239static int
240ng_device_newhook(node_p node, hook_p hook, const char *name)
241{
242	priv_p priv = NG_NODE_PRIVATE(node);
243
244	DBG;
245
246	/* We have only one hook per node */
247	if (priv->hook != NULL)
248		return (EISCONN);
249
250	priv->hook = hook;
251
252	return(0);
253}
254
255/*
256 * Receive data from hook, write it to device.
257 */
258static int
259ng_device_rcvdata(hook_p hook, item_p item)
260{
261	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
262	struct mbuf *m;
263
264	DBG;
265
266	NGI_GET_M(item, m);
267	NG_FREE_ITEM(item);
268
269	IF_LOCK(&priv->readq);
270	if (_IF_QFULL(&priv->readq)) {
271		_IF_DROP(&priv->readq);
272		IF_UNLOCK(&priv->readq);
273		NG_FREE_M(m);
274		return (ENOBUFS);
275	}
276
277	_IF_ENQUEUE(&priv->readq, m);
278	IF_UNLOCK(&priv->readq);
279	mtx_lock(&priv->ngd_mtx);
280	if (priv->flags & NGDF_RWAIT) {
281		priv->flags &= ~NGDF_RWAIT;
282		wakeup(priv);
283	}
284	mtx_unlock(&priv->ngd_mtx);
285
286	return(0);
287}
288
289/*
290 * Removal of the hook destroys the node.
291 */
292static int
293ng_device_disconnect(hook_p hook)
294{
295	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
296
297	DBG;
298
299	destroy_dev(priv->ngddev);
300	mtx_destroy(&priv->ngd_mtx);
301
302	mtx_lock(&ng_device_mtx);
303	SLIST_REMOVE(&ngd_nodes, priv, ngd_private, links);
304	mtx_unlock(&ng_device_mtx);
305
306	IF_DRAIN(&priv->readq);
307	mtx_destroy(&(priv)->readq.ifq_mtx);
308
309	FREE(priv, M_NETGRAPH);
310
311	ng_rmnode_self(NG_HOOK_NODE(hook));
312
313	return(0);
314}
315
316/*
317 * Node shutdown. Everything is already done in disconnect method.
318 */
319static int
320ng_device_shutdown(node_p node)
321{
322	NG_NODE_UNREF(node);
323	return (0);
324}
325
326/******************************************************************************
327 *  Device methods
328 ******************************************************************************/
329
330/*
331 * the device is opened
332 */
333static int
334ngdopen(struct cdev *dev, int flag, int mode, struct thread *td)
335{
336	priv_p	priv = (priv_p )dev->si_drv1;
337
338	DBG;
339
340	mtx_lock(&priv->ngd_mtx);
341	priv->flags |= NGDF_OPEN;
342	mtx_unlock(&priv->ngd_mtx);
343
344	return(0);
345}
346
347/*
348 * the device is closed
349 */
350static int
351ngdclose(struct cdev *dev, int flag, int mode, struct thread *td)
352{
353	priv_p	priv = (priv_p )dev->si_drv1;
354
355	DBG;
356	mtx_lock(&priv->ngd_mtx);
357	priv->flags &= ~NGDF_OPEN;
358	mtx_unlock(&priv->ngd_mtx);
359
360	return(0);
361}
362
363#if 0	/*
364	 * The ioctl is transformed into netgraph control message.
365	 * We do not process them, yet.
366	 */
367/*
368 * process ioctl
369 *
370 * they are translated into netgraph messages and passed on
371 *
372 */
373static int
374ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
375{
376	struct ngd_softc *sc = &ngd_softc;
377	struct ngd_connection * connection = NULL;
378	struct ngd_connection * tmp;
379	int error = 0;
380	struct ng_mesg *msg;
381	struct ngd_param_s * datap;
382
383	DBG;
384
385	SLIST_FOREACH(tmp,&sc->head,links) {
386		if(tmp->ngddev == dev) {
387			connection = tmp;
388		}
389	}
390	if(connection == NULL) {
391		printf("%s(): connection is still NULL, no dev found\n",__func__);
392		return(-1);
393	}
394
395	NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s),
396			M_NOWAIT);
397	if (msg == NULL) {
398		printf("%s(): msg == NULL\n",__func__);
399		goto nomsg;
400	}
401
402	/* pass the ioctl data into the ->data area */
403	datap = (struct ngd_param_s *)msg->data;
404	datap->p = addr;
405
406	NG_SEND_MSG_HOOK(error, sc->node, msg, connection->active_hook, 0);
407	if(error)
408		printf("%s(): NG_SEND_MSG_HOOK error: %d\n",__func__,error);
409
410nomsg:
411
412	return(0);
413}
414#endif /* if 0 */
415
416/*
417 * This function is called when a read(2) is done to our device.
418 * We process one mbuf from queue.
419 */
420static int
421ngdread(struct cdev *dev, struct uio *uio, int flag)
422{
423	priv_p	priv = (priv_p )dev->si_drv1;
424	struct mbuf *m;
425	int len, error = 0;
426
427	DBG;
428
429	/* get an mbuf */
430	do {
431		IF_DEQUEUE(&priv->readq, m);
432		if (m == NULL) {
433			if (flag & IO_NDELAY)
434				return (EWOULDBLOCK);
435			mtx_lock(&priv->ngd_mtx);
436			priv->flags |= NGDF_RWAIT;
437			if ((error = msleep(priv, &priv->ngd_mtx,
438			    PDROP | PCATCH | (PZERO + 1),
439			    "ngdread", 0)) != 0)
440				return (error);
441		}
442	} while (m == NULL);
443
444	while (m && uio->uio_resid > 0 && error == 0) {
445		len = MIN(uio->uio_resid, m->m_len);
446		if (len != 0)
447			error = uiomove(mtod(m, void *), len, uio);
448		m = m_free(m);
449	}
450
451	if (m)
452		m_freem(m);
453
454	return (error);
455}
456
457
458/*
459 * This function is called when our device is written to.
460 * We read the data from userland into mbuf chain and pass it to the remote hook.
461 *
462 */
463static int
464ngdwrite(struct cdev *dev, struct uio *uio, int flag)
465{
466	priv_p	priv = (priv_p )dev->si_drv1;
467	struct mbuf *m;
468	int error = 0;
469
470	DBG;
471
472	if (uio->uio_resid == 0)
473		return (0);
474
475	if (uio->uio_resid < 0 || uio->uio_resid > IP_MAXPACKET)
476		return (EIO);
477
478	if ((m = m_uiotombuf(uio, M_DONTWAIT, 0)) == NULL)
479		return (ENOBUFS);
480
481	NG_SEND_DATA_ONLY(error, priv->hook, m);
482
483	return (error);
484}
485
486/*
487 * we are being polled/selected
488 * check if there is data available for read
489 */
490static int
491ngdpoll(struct cdev *dev, int events, struct thread *td)
492{
493	priv_p	priv = (priv_p )dev->si_drv1;
494	int revents = 0;
495
496	if (events & (POLLIN | POLLRDNORM) &&
497	    !IFQ_IS_EMPTY(&priv->readq))
498		revents |= events & (POLLIN | POLLRDNORM);
499
500	return (revents);
501}
502
503/******************************************************************************
504 *  Helper subroutines
505 ******************************************************************************/
506
507static int
508get_free_unit()
509{
510	struct ngd_private *priv = NULL;
511	int n = 0;
512	int unit = -1;
513
514	DBG;
515
516	mtx_assert(&ng_device_mtx, MA_OWNED);
517
518	/* When there is no list yet, the first device unit is always 0. */
519	if SLIST_EMPTY(&ngd_nodes)
520		return(0);
521
522	/* Just do a brute force loop to find the first free unit that is
523	 * smaller than MAX_NGD.
524	 * Set MAX_NGD to a large value, doesn't impact performance.
525	 */
526	for(n = 0; n<MAX_NGD && unit == -1; n++) {
527		SLIST_FOREACH(priv, &ngd_nodes, links) {
528
529			if(priv->unit == n) {
530				unit = -1;
531				break;
532			}
533			unit = n;
534		}
535	}
536
537	return (unit);
538}
539
540/*
541 * Handle loading and unloading for this node type.
542 */
543static int
544ng_device_mod_event(module_t mod, int event, void *data)
545{
546	int error = 0;
547
548	switch (event) {
549	case MOD_LOAD:
550		mtx_init(&ng_device_mtx, "ng_device", NULL, MTX_DEF);
551		break;
552	case MOD_UNLOAD:
553		mtx_destroy(&ng_device_mtx);
554		break;
555	default:
556		error = EOPNOTSUPP;
557		break;
558	}
559	return (error);
560}
561