xref: /freebsd/sys/netgraph/ng_socket.c (revision b0a5fd8e7a144a1159bee1b0132e231b91e36e07)
1 /*
2  * ng_socket.c
3  */
4 
5 /*-
6  * Copyright (c) 1996-1999 Whistle Communications, Inc.
7  * All rights reserved.
8  *
9  * Subject to the following obligations and disclaimer of warranty, use and
10  * redistribution of this software, in source or object code forms, with or
11  * without modifications are expressly permitted by Whistle Communications;
12  * provided, however, that:
13  * 1. Any and all reproductions of the source or object code must include the
14  *    copyright notice above and the following disclaimer of warranties; and
15  * 2. No rights are granted, in any manner or form, to use Whistle
16  *    Communications, Inc. trademarks, including the mark "WHISTLE
17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
18  *    such appears in the above copyright notice or in the software.
19  *
20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
36  * OF SUCH DAMAGE.
37  *
38  * Author: Julian Elischer <julian@freebsd.org>
39  *
40  * $FreeBSD$
41  * $Whistle: ng_socket.c,v 1.28 1999/11/01 09:24:52 julian Exp $
42  */
43 
44 /*
45  * Netgraph socket nodes
46  *
47  * There are two types of netgraph sockets, control and data.
48  * Control sockets have a netgraph node, but data sockets are
49  * parasitic on control sockets, and have no node of their own.
50  */
51 
52 #include <sys/param.h>
53 #include <sys/domain.h>
54 #include <sys/errno.h>
55 #include <sys/kdb.h>
56 #include <sys/kernel.h>
57 #include <sys/linker.h>
58 #include <sys/lock.h>
59 #include <sys/malloc.h>
60 #include <sys/mbuf.h>
61 #include <sys/mutex.h>
62 #include <sys/protosw.h>
63 #include <sys/queue.h>
64 #include <sys/signalvar.h>
65 #include <sys/socket.h>
66 #include <sys/socketvar.h>
67 #include <sys/sx.h>
68 #include <sys/sysctl.h>
69 #include <sys/systm.h>
70 #ifdef NOTYET
71 #include <sys/vnode.h>
72 #endif
73 #include <netgraph/ng_message.h>
74 #include <netgraph/netgraph.h>
75 #include <netgraph/ng_socketvar.h>
76 #include <netgraph/ng_socket.h>
77 
78 #ifdef NG_SEPARATE_MALLOC
79 MALLOC_DEFINE(M_NETGRAPH_PATH, "netgraph_path", "netgraph path info ");
80 MALLOC_DEFINE(M_NETGRAPH_SOCK, "netgraph_sock", "netgraph socket info ");
81 #else
82 #define M_NETGRAPH_PATH M_NETGRAPH
83 #define M_NETGRAPH_SOCK M_NETGRAPH
84 #endif
85 
86 /*
87  * It's Ascii-art time!
88  *   +-------------+   +-------------+
89  *   |socket  (ctl)|   |socket (data)|
90  *   +-------------+   +-------------+
91  *          ^                 ^
92  *          |                 |
93  *          v                 v
94  *    +-----------+     +-----------+
95  *    |pcb   (ctl)|     |pcb  (data)|
96  *    +-----------+     +-----------+
97  *          ^                 ^
98  *          |                 |
99  *          v                 v
100  *      +--------------------------+
101  *      |   Socket type private    |
102  *      |       data               |
103  *      +--------------------------+
104  *                   ^
105  *                   |
106  *                   v
107  *           +----------------+
108  *           | struct ng_node |
109  *           +----------------+
110  */
111 
112 /* Netgraph node methods */
113 static ng_constructor_t	ngs_constructor;
114 static ng_rcvmsg_t	ngs_rcvmsg;
115 static ng_shutdown_t	ngs_shutdown;
116 static ng_newhook_t	ngs_newhook;
117 static ng_connect_t	ngs_connect;
118 static ng_rcvdata_t	ngs_rcvdata;
119 static ng_disconnect_t	ngs_disconnect;
120 
121 /* Internal methods */
122 static int	ng_attach_data(struct socket *so);
123 static int	ng_attach_cntl(struct socket *so);
124 static int	ng_attach_common(struct socket *so, int type);
125 static void	ng_detach_common(struct ngpcb *pcbp, int type);
126 /*static int	ng_internalize(struct mbuf *m, struct thread *p); */
127 
128 static int	ng_connect_data(struct sockaddr *nam, struct ngpcb *pcbp);
129 static int	ng_bind(struct sockaddr *nam, struct ngpcb *pcbp);
130 
131 static int	ngs_mod_event(module_t mod, int event, void *data);
132 static int	ship_msg(struct ngpcb *pcbp, struct ng_mesg *msg,
133 			struct sockaddr_ng *addr);
134 
135 /* Netgraph type descriptor */
136 static struct ng_type typestruct = {
137 	.version =	NG_ABI_VERSION,
138 	.name =		NG_SOCKET_NODE_TYPE,
139 	.mod_event =	ngs_mod_event,
140 	.constructor =	ngs_constructor,
141 	.rcvmsg =	ngs_rcvmsg,
142 	.shutdown =	ngs_shutdown,
143 	.newhook =	ngs_newhook,
144 	.connect =	ngs_connect,
145 	.rcvdata =	ngs_rcvdata,
146 	.disconnect =	ngs_disconnect,
147 };
148 NETGRAPH_INIT_ORDERED(socket, &typestruct, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
149 
150 /* Buffer space */
151 static u_long ngpdg_sendspace = 20 * 1024;	/* really max datagram size */
152 SYSCTL_INT(_net_graph, OID_AUTO, maxdgram, CTLFLAG_RW,
153     &ngpdg_sendspace , 0, "Maximum outgoing Netgraph datagram size");
154 static u_long ngpdg_recvspace = 20 * 1024;
155 SYSCTL_INT(_net_graph, OID_AUTO, recvspace, CTLFLAG_RW,
156     &ngpdg_recvspace , 0, "Maximum space for incoming Netgraph datagrams");
157 
158 /* List of all sockets */
159 static LIST_HEAD(, ngpcb) ngsocklist;
160 
161 static struct mtx	ngsocketlist_mtx;
162 MTX_SYSINIT(ngsocketlist, &ngsocketlist_mtx, "ng_socketlist", MTX_DEF);
163 
164 #define sotongpcb(so) ((struct ngpcb *)(so)->so_pcb)
165 
166 /* If getting unexplained errors returned, set this to "kdb_enter("X"); */
167 #ifndef TRAP_ERROR
168 #define TRAP_ERROR
169 #endif
170 
171 /***************************************************************
172 	Control sockets
173 ***************************************************************/
174 
175 static int
176 ngc_attach(struct socket *so, int proto, struct thread *td)
177 {
178 	struct ngpcb *const pcbp = sotongpcb(so);
179 
180 	if (suser(td))
181 		return (EPERM);
182 	if (pcbp != NULL)
183 		return (EISCONN);
184 	return (ng_attach_cntl(so));
185 }
186 
187 static int
188 ngc_detach(struct socket *so)
189 {
190 	struct ngpcb *const pcbp = sotongpcb(so);
191 
192 	if (pcbp == NULL)
193 		return (EINVAL);
194 	ng_detach_common(pcbp, NG_CONTROL);
195 	return (0);
196 }
197 
198 static int
199 ngc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr,
200 	 struct mbuf *control, struct thread *td)
201 {
202 	struct ngpcb *const pcbp = sotongpcb(so);
203 	struct sockaddr_ng *const sap = (struct sockaddr_ng *) addr;
204 	struct ng_mesg *msg;
205 	struct mbuf *m0;
206 	char *path = NULL;
207 	int len, error = 0;
208 
209 	if (pcbp == NULL) {
210 		error = EINVAL;
211 		goto release;
212 	}
213 #ifdef	NOTYET
214 	if (control && (error = ng_internalize(control, td))) {
215 		if (pcbp->sockdata == NULL) {
216 			error = ENOTCONN;
217 			goto release;
218 		}
219 	}
220 #else	/* NOTYET */
221 	if (control) {
222 		error = EINVAL;
223 		goto release;
224 	}
225 #endif	/* NOTYET */
226 
227 	/* Require destination as there may be >= 1 hooks on this node */
228 	if (addr == NULL) {
229 		error = EDESTADDRREQ;
230 		goto release;
231 	}
232 
233 	/* Allocate an expendable buffer for the path, chop off
234 	 * the sockaddr header, and make sure it's NUL terminated */
235 	len = sap->sg_len - 2;
236 	MALLOC(path, char *, len + 1, M_NETGRAPH_PATH, M_WAITOK);
237 	if (path == NULL) {
238 		error = ENOMEM;
239 		goto release;
240 	}
241 	bcopy(sap->sg_data, path, len);
242 	path[len] = '\0';
243 
244 	/* Move the actual message out of mbufs into a linear buffer.
245 	 * Start by adding up the size of the data. (could use mh_len?) */
246 	for (len = 0, m0 = m; m0 != NULL; m0 = m0->m_next)
247 		len += m0->m_len;
248 
249 	/* Move the data into a linear buffer as well. Messages are not
250 	 * delivered in mbufs. */
251 	MALLOC(msg, struct ng_mesg *, len + 1, M_NETGRAPH_MSG, M_WAITOK);
252 	if (msg == NULL) {
253 		error = ENOMEM;
254 		goto release;
255 	}
256 	m_copydata(m, 0, len, (char *)msg);
257 
258 #ifdef TRACE_MESSAGES
259 	do {
260 		item_p item;
261 		if ((item = ng_package_msg(msg)) == NULL) {
262 			(msg) = NULL;
263 			(error) = ENOMEM;
264 printf("err=%d\n",error);
265 			break;
266 		}
267 		if (((error) = ng_address_path((pcbp->sockdata->node), (item),
268 					(path), (NULL))) == 0) {
269 printf("[%x]:<---------[socket]: c=<%d>cmd=%x(%s) f=%x #%d (%s)\n",
270 item->el_dest->nd_ID,
271 msg->header.typecookie,
272 msg->header.cmd,
273 msg->header.cmdstr,
274 msg->header.flags,
275 msg->header.token,
276 item->el_dest->nd_type->name);
277 			SAVE_LINE(item);
278 			(error) = ng_snd_item((item), 0);
279 		}
280 else {
281 printf("errx=%d\n",error);
282 }
283 		(msg) = NULL;
284 	} while (0);
285 
286 #else
287 	/*
288 	 * Hack alert!
289 	 * We look into the message and if it mkpeers a node of unknown type, we
290 	 * try to load it. We need to do this now, in syscall thread, because if
291 	 * message gets queued and applied later we will get panic.
292 	 */
293 	if (msg->header.typecookie == NGM_GENERIC_COOKIE &&
294 	    msg->header.cmd == NGM_MKPEER) {
295 		struct ngm_mkpeer *const mkp = (struct ngm_mkpeer *) msg->data;
296 		struct ng_type *type;
297 
298 		if ((type = ng_findtype(mkp->type)) == NULL) {
299 			char filename[NG_TYPESIZ + 3];
300 			linker_file_t lf;
301 			int error;
302 
303 			/* Not found, try to load it as a loadable module */
304 			snprintf(filename, sizeof(filename), "ng_%s", mkp->type);
305 			mtx_lock(&Giant);
306 			error = linker_load_module(NULL, filename, NULL, NULL, &lf);
307 			mtx_unlock(&Giant);
308 			if (error != 0) {
309 				FREE(msg, M_NETGRAPH_MSG);
310 				goto release;
311 			}
312 			lf->userrefs++;
313 
314 			/* Try again, as now the type should have linked itself in */
315 			if ((type = ng_findtype(mkp->type)) == NULL) {
316 				FREE(msg, M_NETGRAPH_MSG);
317 				error =  ENXIO;
318 				goto release;
319 			}
320 		}
321 	}
322 
323 	/* The callee will free the msg when done. The path is our business. */
324 	NG_SEND_MSG_PATH(error, pcbp->sockdata->node, msg, path, 0);
325 #endif
326 release:
327 	if (path != NULL)
328 		FREE(path, M_NETGRAPH_PATH);
329 	if (control != NULL)
330 		m_freem(control);
331 	if (m != NULL)
332 		m_freem(m);
333 	return (error);
334 }
335 
336 static int
337 ngc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
338 {
339 	struct ngpcb *const pcbp = sotongpcb(so);
340 
341 	if (pcbp == 0)
342 		return (EINVAL);
343 	return (ng_bind(nam, pcbp));
344 }
345 
346 static int
347 ngc_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
348 {
349 printf(" program tried to connect control socket to remote node\n ");
350 	/*
351 	 * At this time refuse to do this.. it used to
352 	 * do something but it was undocumented and not used.
353 	 */
354 	return (EINVAL);
355 }
356 
357 /***************************************************************
358 	Data sockets
359 ***************************************************************/
360 
361 static int
362 ngd_attach(struct socket *so, int proto, struct thread *td)
363 {
364 	struct ngpcb *const pcbp = sotongpcb(so);
365 
366 	if (pcbp != NULL)
367 		return (EISCONN);
368 	return (ng_attach_data(so));
369 }
370 
371 static int
372 ngd_detach(struct socket *so)
373 {
374 	struct ngpcb *const pcbp = sotongpcb(so);
375 
376 	if (pcbp == NULL)
377 		return (EINVAL);
378 	ng_detach_common(pcbp, NG_DATA);
379 	return (0);
380 }
381 
382 static int
383 ngd_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr,
384 	 struct mbuf *control, struct thread *td)
385 {
386 	struct ngpcb *const pcbp = sotongpcb(so);
387 	struct sockaddr_ng *const sap = (struct sockaddr_ng *) addr;
388 	int     len, error;
389 	hook_p  hook = NULL;
390 	char	hookname[NG_HOOKSIZ];
391 
392 	if ((pcbp == NULL) || (control != NULL)) {
393 		error = EINVAL;
394 		goto release;
395 	}
396 	if (pcbp->sockdata == NULL) {
397 		error = ENOTCONN;
398 		goto release;
399 	}
400 	/*
401 	 * If the user used any of these ways to not specify an address
402 	 * then handle specially.
403 	 */
404 	if ((sap == NULL)
405 	    || ((len = sap->sg_len - 2) <= 0)
406 	    || (*sap->sg_data == '\0')) {
407 		if (NG_NODE_NUMHOOKS(pcbp->sockdata->node) != 1) {
408 			error = EDESTADDRREQ;
409 			goto release;
410 		}
411 		/*
412 		 * if exactly one hook exists, just use it.
413 		 * Special case to allow write(2) to work on an ng_socket.
414 		 */
415 		hook = LIST_FIRST(&pcbp->sockdata->node->nd_hooks);
416 	} else {
417 		if (len >= NG_HOOKSIZ) {
418 			error = EINVAL;
419 			goto release;
420 		}
421 
422 		/*
423 		 * chop off the sockaddr header, and make sure it's NUL
424 		 * terminated
425 		 */
426 		bcopy(sap->sg_data, hookname, len);
427 		hookname[len] = '\0';
428 
429 		/* Find the correct hook from 'hookname' */
430 		LIST_FOREACH(hook, &pcbp->sockdata->node->nd_hooks, hk_hooks) {
431 			if (strcmp(hookname, NG_HOOK_NAME(hook)) == 0) {
432 				break;
433 			}
434 		}
435 		if (hook == NULL) {
436 			error = EHOSTUNREACH;
437 		}
438 	}
439 
440 	/* Send data (OK if hook is NULL) */
441 	NG_SEND_DATA_ONLY(error, hook, m);	/* makes m NULL */
442 
443 release:
444 	if (control != NULL)
445 		m_freem(control);
446 	if (m != NULL)
447 		m_freem(m);
448 	return (error);
449 }
450 
451 static int
452 ngd_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
453 {
454 	struct ngpcb *const pcbp = sotongpcb(so);
455 
456 	if (pcbp == 0)
457 		return (EINVAL);
458 	return (ng_connect_data(nam, pcbp));
459 }
460 
461 /*
462  * Used for both data and control sockets
463  */
464 static int
465 ng_setsockaddr(struct socket *so, struct sockaddr **addr)
466 {
467 	struct ngpcb *pcbp;
468 	struct sockaddr_ng *sg;
469 	int sg_len, namelen, s;
470 
471 	/* Why isn't sg_data a `char[1]' ? :-( */
472 	sg_len = sizeof(struct sockaddr_ng) - sizeof(sg->sg_data) + 1;
473 
474 	s = splnet();
475 	pcbp = sotongpcb(so);
476 	if ((pcbp == NULL) || (pcbp->sockdata == NULL)) {
477 		splx(s);
478 		return (EINVAL);
479 	}
480 
481 	namelen = 0;		/* silence compiler ! */
482 	if ( NG_NODE_HAS_NAME(pcbp->sockdata->node))
483 		sg_len += namelen = strlen(NG_NODE_NAME(pcbp->sockdata->node));
484 
485 	MALLOC(sg, struct sockaddr_ng *, sg_len, M_SONAME, M_WAITOK | M_ZERO);
486 
487 	if (NG_NODE_HAS_NAME(pcbp->sockdata->node))
488 		bcopy(NG_NODE_NAME(pcbp->sockdata->node), sg->sg_data, namelen);
489 	splx(s);
490 
491 	sg->sg_len = sg_len;
492 	sg->sg_family = AF_NETGRAPH;
493 	*addr = (struct sockaddr *)sg;
494 
495 	return (0);
496 }
497 
498 /*
499  * Attach a socket to it's protocol specific partner.
500  * For a control socket, actually create a netgraph node and attach
501  * to it as well.
502  */
503 
504 static int
505 ng_attach_cntl(struct socket *so)
506 {
507 	struct ngsock *privdata;
508 	struct ngpcb *pcbp;
509 	int error;
510 
511 	/* Setup protocol control block */
512 	if ((error = ng_attach_common(so, NG_CONTROL)) != 0)
513 		return (error);
514 	pcbp = sotongpcb(so);
515 
516 	/* Allocate node private info */
517 	MALLOC(privdata, struct ngsock *,
518 	    sizeof(*privdata), M_NETGRAPH_SOCK, M_WAITOK | M_ZERO);
519 	if (privdata == NULL) {
520 		ng_detach_common(pcbp, NG_CONTROL);
521 		return (ENOMEM);
522 	}
523 
524 	/* Make the generic node components */
525 	if ((error = ng_make_node_common(&typestruct, &privdata->node)) != 0) {
526 		FREE(privdata, M_NETGRAPH_SOCK);
527 		ng_detach_common(pcbp, NG_CONTROL);
528 		return (error);
529 	}
530 	NG_NODE_SET_PRIVATE(privdata->node, privdata);
531 
532 	/* Link the pcb and the node private data */
533 	privdata->ctlsock = pcbp;
534 	pcbp->sockdata = privdata;
535 	privdata->refs++;
536 	return (0);
537 }
538 
539 static int
540 ng_attach_data(struct socket *so)
541 {
542 	return(ng_attach_common(so, NG_DATA));
543 }
544 
545 /*
546  * Set up a socket protocol control block.
547  * This code is shared between control and data sockets.
548  */
549 static int
550 ng_attach_common(struct socket *so, int type)
551 {
552 	struct ngpcb *pcbp;
553 	int error;
554 
555 	/* Standard socket setup stuff */
556 	error = soreserve(so, ngpdg_sendspace, ngpdg_recvspace);
557 	if (error)
558 		return (error);
559 
560 	/* Allocate the pcb */
561 	MALLOC(pcbp, struct ngpcb *, sizeof(*pcbp), M_PCB, M_WAITOK | M_ZERO);
562 	if (pcbp == NULL)
563 		return (ENOMEM);
564 	pcbp->type = type;
565 
566 	/* Link the pcb and the socket */
567 	so->so_pcb = (caddr_t) pcbp;
568 	pcbp->ng_socket = so;
569 
570 	/* Add the socket to linked list */
571 	mtx_lock(&ngsocketlist_mtx);
572 	LIST_INSERT_HEAD(&ngsocklist, pcbp, socks);
573 	mtx_unlock(&ngsocketlist_mtx);
574 	return (0);
575 }
576 
577 /*
578  * Disassociate the socket from it's protocol specific
579  * partner. If it's attached to a node's private data structure,
580  * then unlink from that too. If we were the last socket attached to it,
581  * then shut down the entire node. Shared code for control and data sockets.
582  */
583 static void
584 ng_detach_common(struct ngpcb *pcbp, int which)
585 {
586 	struct ngsock *priv;
587 
588 	if (pcbp->sockdata) {
589 		priv = pcbp->sockdata;
590 		pcbp->sockdata = NULL;
591 		switch (which) {
592 		case NG_CONTROL:
593 			priv->ctlsock = NULL;
594 			break;
595 		case NG_DATA:
596 			priv->datasock = NULL;
597 			break;
598 		default:
599 			panic(__func__);
600 		}
601 		if ((--priv->refs == 0) && (priv->node != NULL))
602 			ng_rmnode_self(priv->node);
603 	}
604 	pcbp->ng_socket->so_pcb = NULL;
605 	pcbp->ng_socket = NULL;
606 	mtx_lock(&ngsocketlist_mtx);
607 	LIST_REMOVE(pcbp, socks);
608 	mtx_unlock(&ngsocketlist_mtx);
609 	FREE(pcbp, M_PCB);
610 }
611 
612 #ifdef NOTYET
613 /*
614  * File descriptors can be passed into an AF_NETGRAPH socket.
615  * Note, that file descriptors cannot be passed OUT.
616  * Only character device descriptors are accepted.
617  * Character devices are useful to connect a graph to a device,
618  * which after all is the purpose of this whole system.
619  */
620 static int
621 ng_internalize(struct mbuf *control, struct thread *td)
622 {
623 	const struct cmsghdr *cm = mtod(control, const struct cmsghdr *);
624 	struct file *fp;
625 	struct vnode *vn;
626 	int oldfds;
627 	int fd;
628 
629 	if (cm->cmsg_type != SCM_RIGHTS || cm->cmsg_level != SOL_SOCKET ||
630 	    cm->cmsg_len != control->m_len) {
631 		TRAP_ERROR;
632 		return (EINVAL);
633 	}
634 
635 	/* Check there is only one FD. XXX what would more than one signify? */
636 	oldfds = ((caddr_t)cm + cm->cmsg_len - (caddr_t)data) / sizeof (int);
637 	if (oldfds != 1) {
638 		TRAP_ERROR;
639 		return (EINVAL);
640 	}
641 
642 	/* Check that the FD given is legit. and change it to a pointer to a
643 	 * struct file. */
644 	fd = CMSG_DATA(cm);
645 	if ((error = fget(td, fd, &fp)) != 0)
646 		return (error);
647 
648 	/* Depending on what kind of resource it is, act differently. For
649 	 * devices, we treat it as a file. For an AF_NETGRAPH socket,
650 	 * shortcut straight to the node. */
651 	switch (fp->f_type) {
652 	case DTYPE_VNODE:
653 		vn = fp->f_data;
654 		if (vn && (vn->v_type == VCHR)) {
655 			/* for a VCHR, actually reference the FILE */
656 			fp->f_count++;
657 			/* XXX then what :) */
658 			/* how to pass on to other modules? */
659 		} else {
660 			fdrop(fp, td);
661 			TRAP_ERROR;
662 			return (EINVAL);
663 		}
664 		break;
665 	default:
666 		fdrop(fp, td);
667 		TRAP_ERROR;
668 		return (EINVAL);
669 	}
670 	fdrop(fp, td);
671 	return (0);
672 }
673 #endif	/* NOTYET */
674 
675 /*
676  * Connect the data socket to a named control socket node.
677  */
678 static int
679 ng_connect_data(struct sockaddr *nam, struct ngpcb *pcbp)
680 {
681 	struct sockaddr_ng *sap;
682 	node_p farnode;
683 	struct ngsock *priv;
684 	int error;
685 	item_p item;
686 
687 	/* If we are already connected, don't do it again */
688 	if (pcbp->sockdata != NULL)
689 		return (EISCONN);
690 
691 	/* Find the target (victim) and check it doesn't already have a data
692 	 * socket. Also check it is a 'socket' type node.
693 	 * Use ng_package_data() and address_path() to do this.
694 	 */
695 
696 	sap = (struct sockaddr_ng *) nam;
697 	/* The item will hold the node reference */
698 	item = ng_package_data(NULL, NULL);
699 	if (item == NULL) {
700 		return (ENOMEM);
701 	}
702 	if ((error = ng_address_path(NULL, item,  sap->sg_data, 0)))
703 		return (error); /* item is freed on failure */
704 
705 	/*
706 	 * Extract node from item and free item. Remember we now have
707 	 * a reference on the node. The item holds it for us.
708 	 * when we free the item we release the reference.
709 	 */
710 	farnode = item->el_dest; /* shortcut */
711 	if (strcmp(farnode->nd_type->name, NG_SOCKET_NODE_TYPE) != 0) {
712 		NG_FREE_ITEM(item); /* drop the reference to the node */
713 		return (EINVAL);
714 	}
715 	priv = NG_NODE_PRIVATE(farnode);
716 	if (priv->datasock != NULL) {
717 		NG_FREE_ITEM(item);	/* drop the reference to the node */
718 		return (EADDRINUSE);
719 	}
720 
721 	/*
722 	 * Link the PCB and the private data struct. and note the extra
723 	 * reference. Drop the extra reference on the node.
724 	 */
725 	priv->datasock = pcbp;
726 	pcbp->sockdata = priv;
727 	priv->refs++; /* XXX possible race if it's being freed */
728 	NG_FREE_ITEM(item);	/* drop the reference to the node */
729 	return (0);
730 }
731 
732 /*
733  * Binding a socket means giving the corresponding node a name
734  */
735 static int
736 ng_bind(struct sockaddr *nam, struct ngpcb *pcbp)
737 {
738 	struct ngsock *const priv = pcbp->sockdata;
739 	struct sockaddr_ng *const sap = (struct sockaddr_ng *) nam;
740 
741 	if (priv == NULL) {
742 		TRAP_ERROR;
743 		return (EINVAL);
744 	}
745 	if ((sap->sg_len < 4)
746 	||  (sap->sg_len > (NG_NODESIZ + 2))
747 	||  (sap->sg_data[0] == '\0')
748 	||  (sap->sg_data[sap->sg_len - 3] != '\0')) {
749 		TRAP_ERROR;
750 		return (EINVAL);
751 	}
752 	return (ng_name_node(priv->node, sap->sg_data));
753 }
754 
755 /*
756  * Take a message and pass it up to the control socket associated
757  * with the node.
758  */
759 static int
760 ship_msg(struct ngpcb *pcbp, struct ng_mesg *msg, struct sockaddr_ng *addr)
761 {
762 	struct socket *const so = pcbp->ng_socket;
763 	struct mbuf *mdata;
764 	int msglen;
765 
766 	/* Copy the message itself into an mbuf chain */
767 	msglen = sizeof(struct ng_mesg) + msg->header.arglen;
768 	mdata = m_devget((caddr_t) msg, msglen, 0, NULL, NULL);
769 
770 	/* Here we free the message, as we are the end of the line.
771 	 * We need to do that regardless of whether we got mbufs. */
772 	NG_FREE_MSG(msg);
773 
774 	if (mdata == NULL) {
775 		TRAP_ERROR;
776 		return (ENOBUFS);
777 	}
778 
779 	/* Send it up to the socket */
780 	if (sbappendaddr(&so->so_rcv,
781 	    (struct sockaddr *) addr, mdata, NULL) == 0) {
782 		TRAP_ERROR;
783 		m_freem(mdata);
784 		return (ENOBUFS);
785 	}
786 	sorwakeup(so);
787 	return (0);
788 }
789 
790 /*
791  * You can only create new nodes from the socket end of things.
792  */
793 static int
794 ngs_constructor(node_p nodep)
795 {
796 	return (EINVAL);
797 }
798 
799 /*
800  * We allow any hook to be connected to the node.
801  * There is no per-hook private information though.
802  */
803 static int
804 ngs_newhook(node_p node, hook_p hook, const char *name)
805 {
806 	NG_HOOK_SET_PRIVATE(hook, NG_NODE_PRIVATE(node));
807 	return (0);
808 }
809 
810 /*
811  * if only one hook, allow read(2) and write(2) to work.
812  */
813 static int
814 ngs_connect(hook_p hook)
815 {
816 	node_p node = NG_HOOK_NODE(hook);
817 	struct ngsock *priv = NG_NODE_PRIVATE(node);
818 
819 	if ((priv->datasock)
820 	&&  (priv->datasock->ng_socket)) {
821 		if (NG_NODE_NUMHOOKS(node) == 1) {
822 			priv->datasock->ng_socket->so_state |= SS_ISCONNECTED;
823 		} else {
824 			priv->datasock->ng_socket->so_state &= ~SS_ISCONNECTED;
825 		}
826 	}
827 	return (0);
828 }
829 
830 /*
831  * Incoming messages get passed up to the control socket.
832  * Unless they are for us specifically (socket_type)
833  */
834 static int
835 ngs_rcvmsg(node_p node, item_p item, hook_p lasthook)
836 {
837 	struct ngsock *const priv = NG_NODE_PRIVATE(node);
838 	struct ngpcb *const pcbp = priv->ctlsock;
839 	struct sockaddr_ng *addr;
840 	int addrlen;
841 	int error = 0;
842 	struct	ng_mesg *msg;
843 	ng_ID_t	retaddr = NGI_RETADDR(item);
844 	char	retabuf[32];
845 
846 	NGI_GET_MSG(item, msg);
847 	NG_FREE_ITEM(item); /* we have all we need */
848 
849 	/* Only allow mesgs to be passed if we have the control socket.
850 	 * Data sockets can only support the generic messages. */
851 	if (pcbp == NULL) {
852 		TRAP_ERROR;
853 		return (EINVAL);
854 	}
855 #ifdef TRACE_MESSAGES
856 printf("[%x]:---------->[socket]: c=<%d>cmd=%x(%s) f=%x #%d\n",
857 retaddr,
858 msg->header.typecookie,
859 msg->header.cmd,
860 msg->header.cmdstr,
861 msg->header.flags,
862 msg->header.token);
863 
864 #endif
865 
866 	if (msg->header.typecookie == NGM_SOCKET_COOKIE) {
867 		switch (msg->header.cmd) {
868 		case NGM_SOCK_CMD_NOLINGER:
869 			priv->flags |= NGS_FLAG_NOLINGER;
870 			break;
871 		case NGM_SOCK_CMD_LINGER:
872 			priv->flags &= ~NGS_FLAG_NOLINGER;
873 			break;
874 		default:
875 			error = EINVAL;		/* unknown command */
876 		}
877 		/* Free the message and return */
878 		NG_FREE_MSG(msg);
879 		return(error);
880 
881 	}
882 	/* Get the return address into a sockaddr */
883 	sprintf(retabuf,"[%x]:", retaddr);
884 	addrlen = strlen(retabuf);
885 	MALLOC(addr, struct sockaddr_ng *, addrlen + 4, M_NETGRAPH_PATH, M_NOWAIT);
886 	if (addr == NULL) {
887 		TRAP_ERROR;
888 		return (ENOMEM);
889 	}
890 	addr->sg_len = addrlen + 3;
891 	addr->sg_family = AF_NETGRAPH;
892 	bcopy(retabuf, addr->sg_data, addrlen);
893 	addr->sg_data[addrlen] = '\0';
894 
895 	/* Send it up */
896 	error = ship_msg(pcbp, msg, addr);
897 	FREE(addr, M_NETGRAPH_PATH);
898 	return (error);
899 }
900 
901 /*
902  * Receive data on a hook
903  */
904 static int
905 ngs_rcvdata(hook_p hook, item_p item)
906 {
907 	struct ngsock *const priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
908 	struct ngpcb *const pcbp = priv->datasock;
909 	struct socket *so;
910 	struct sockaddr_ng *addr;
911 	char *addrbuf[NG_HOOKSIZ + 4];
912 	int addrlen;
913 	struct mbuf *m;
914 
915 	NGI_GET_M(item, m);
916 	NG_FREE_ITEM(item);
917 	/* If there is no data socket, black-hole it */
918 	if (pcbp == NULL) {
919 		NG_FREE_M(m);
920 		return (0);
921 	}
922 	so = pcbp->ng_socket;
923 
924 	/* Get the return address into a sockaddr. */
925 	addrlen = strlen(NG_HOOK_NAME(hook));	/* <= NG_HOOKSIZ - 1 */
926 	addr = (struct sockaddr_ng *) addrbuf;
927 	addr->sg_len = addrlen + 3;
928 	addr->sg_family = AF_NETGRAPH;
929 	bcopy(NG_HOOK_NAME(hook), addr->sg_data, addrlen);
930 	addr->sg_data[addrlen] = '\0';
931 
932 	/* Try to tell the socket which hook it came in on */
933 	if (sbappendaddr(&so->so_rcv, (struct sockaddr *) addr, m, NULL) == 0) {
934 		m_freem(m);
935 		TRAP_ERROR;
936 		return (ENOBUFS);
937 	}
938 	sorwakeup(so);
939 	return (0);
940 }
941 
942 /*
943  * Hook disconnection
944  *
945  * For this type, removal of the last link destroys the node
946  * if the NOLINGER flag is set.
947  */
948 static int
949 ngs_disconnect(hook_p hook)
950 {
951 	node_p node = NG_HOOK_NODE(hook);
952 	struct ngsock *const priv = NG_NODE_PRIVATE(node);
953 
954 	if ((priv->datasock)
955 	&&  (priv->datasock->ng_socket)) {
956 		if (NG_NODE_NUMHOOKS(node) == 1) {
957 			priv->datasock->ng_socket->so_state |= SS_ISCONNECTED;
958 		} else {
959 			priv->datasock->ng_socket->so_state &= ~SS_ISCONNECTED;
960 		}
961 	}
962 
963 	if ((priv->flags & NGS_FLAG_NOLINGER )
964 	&& (NG_NODE_NUMHOOKS(node) == 0)
965 	&& (NG_NODE_IS_VALID(node))) {
966 		ng_rmnode_self(node);
967 	}
968 	return (0);
969 }
970 
971 /*
972  * Do local shutdown processing.
973  * In this case, that involves making sure the socket
974  * knows we should be shutting down.
975  */
976 static int
977 ngs_shutdown(node_p node)
978 {
979 	struct ngsock *const priv = NG_NODE_PRIVATE(node);
980 	struct ngpcb *const dpcbp = priv->datasock;
981 	struct ngpcb *const pcbp = priv->ctlsock;
982 
983 	if (dpcbp != NULL) {
984 		soisdisconnected(dpcbp->ng_socket);
985 		dpcbp->sockdata = NULL;
986 		priv->datasock = NULL;
987 		priv->refs--;
988 	}
989 	if (pcbp != NULL) {
990 		soisdisconnected(pcbp->ng_socket);
991 		pcbp->sockdata = NULL;
992 		priv->ctlsock = NULL;
993 		priv->refs--;
994 	}
995 	NG_NODE_SET_PRIVATE(node, NULL);
996 	NG_NODE_UNREF(node);
997 	FREE(priv, M_NETGRAPH_SOCK);
998 	return (0);
999 }
1000 
1001 static	int
1002 dummy_disconnect(struct socket *so)
1003 {
1004 	return (0);
1005 }
1006 /*
1007  * Control and data socket type descriptors
1008  */
1009 
1010 static struct pr_usrreqs ngc_usrreqs = {
1011 	.pru_abort =		NULL,
1012 	.pru_attach =		ngc_attach,
1013 	.pru_bind =		ngc_bind,
1014 	.pru_connect =		ngc_connect,
1015 	.pru_detach =		ngc_detach,
1016 	.pru_disconnect =	dummy_disconnect,
1017 	.pru_peeraddr =		NULL,
1018 	.pru_send =		ngc_send,
1019 	.pru_shutdown =		NULL,
1020 	.pru_sockaddr =		ng_setsockaddr,
1021 };
1022 
1023 static struct pr_usrreqs ngd_usrreqs = {
1024 	.pru_abort =		NULL,
1025 	.pru_attach =		ngd_attach,
1026 	.pru_bind =		NULL,
1027 	.pru_connect =		ngd_connect,
1028 	.pru_detach =		ngd_detach,
1029 	.pru_disconnect =	dummy_disconnect,
1030 	.pru_peeraddr =		NULL,
1031 	.pru_send =		ngd_send,
1032 	.pru_shutdown =		NULL,
1033 	.pru_sockaddr		ng_setsockaddr,
1034 };
1035 
1036 /*
1037  * Definitions of protocols supported in the NETGRAPH domain.
1038  */
1039 
1040 extern struct domain ngdomain;		/* stop compiler warnings */
1041 
1042 static struct protosw ngsw[] = {
1043 	{
1044 		SOCK_DGRAM,		/* protocol type */
1045 		&ngdomain,		/* backpointer to domain */
1046 		NG_CONTROL,
1047 		PR_ATOMIC | PR_ADDR /* | PR_RIGHTS */,	/* flags */
1048 		0, 0, 0, 0,		/* input, output, ctlinput, ctloutput */
1049 		NULL,			/* ousrreq */
1050 		0, 0, 0, 0,		/* init, fasttimeo, slowtimo, drain */
1051 		&ngc_usrreqs,		/* usrreq table (above) */
1052 		/*{NULL}*/		/* pffh (protocol filter head?) */
1053 	},
1054 	{
1055 		SOCK_DGRAM,		/* protocol type */
1056 		&ngdomain,		/* backpointer to domain */
1057 		NG_DATA,
1058 		PR_ATOMIC | PR_ADDR,	/* flags */
1059 		0, 0, 0, 0,		/* input, output, ctlinput, ctloutput */
1060 		NULL,			/* ousrreq() */
1061 		0, 0, 0, 0,		/* init, fasttimeo, slowtimo, drain */
1062 		&ngd_usrreqs,		/* usrreq table (above) */
1063 		/*{NULL}*/		/* pffh (protocol filter head?) */
1064 	}
1065 };
1066 
1067 struct domain ngdomain = {
1068 	AF_NETGRAPH,
1069 	"netgraph",
1070 	NULL,					/* init() */
1071 	NULL,					/* externalise() */
1072 	NULL,					/* dispose() */
1073 	ngsw,					/* protosw entry */
1074 	&ngsw[sizeof(ngsw) / sizeof(ngsw[0])], 	/* Number of protosw entries */
1075 	NULL,					/* next domain in list */
1076 	NULL,					/* rtattach() */
1077 	0,					/* arg to rtattach in bits */
1078 	0					/* maxrtkey */
1079 };
1080 
1081 /*
1082  * Handle loading and unloading for this node type
1083  * This is to handle auxiliary linkages (e.g protocol domain addition).
1084  */
1085 static int
1086 ngs_mod_event(module_t mod, int event, void *data)
1087 {
1088 	int error = 0;
1089 
1090 	switch (event) {
1091 	case MOD_LOAD:
1092 		/* Register protocol domain */
1093 		net_add_domain(&ngdomain);
1094 		break;
1095 	case MOD_UNLOAD:
1096 		/* Insure there are no open netgraph sockets */
1097 		if (!LIST_EMPTY(&ngsocklist)) {
1098 			error = EBUSY;
1099 			break;
1100 		}
1101 
1102 #ifdef NOTYET
1103 		if ((LIST_EMPTY(&ngsocklist)) && (typestruct.refs == 0)) {
1104 		/* Unregister protocol domain XXX can't do this yet.. */
1105 			if ((error = net_rm_domain(&ngdomain)) != 0)
1106 				break;
1107 		} else
1108 #endif
1109 			error = EBUSY;
1110 		break;
1111 	default:
1112 		error = EOPNOTSUPP;
1113 		break;
1114 	}
1115 	return (error);
1116 }
1117 
1118 SYSCTL_INT(_net_graph, OID_AUTO, family, CTLFLAG_RD, 0, AF_NETGRAPH, "");
1119 SYSCTL_NODE(_net_graph, OID_AUTO, data, CTLFLAG_RW, 0, "DATA");
1120 SYSCTL_INT(_net_graph_data, OID_AUTO, proto, CTLFLAG_RD, 0, NG_DATA, "");
1121 SYSCTL_NODE(_net_graph, OID_AUTO, control, CTLFLAG_RW, 0, "CONTROL");
1122 SYSCTL_INT(_net_graph_control, OID_AUTO, proto, CTLFLAG_RD, 0, NG_CONTROL, "");
1123 
1124