1
2/*
3 * ng_ether.c
4 *
5 * Copyright (c) 1996-2000 Whistle Communications, Inc.
6 * All rights reserved.
7 *
8 * Subject to the following obligations and disclaimer of warranty, use and
9 * redistribution of this software, in source or object code forms, with or
10 * without modifications are expressly permitted by Whistle Communications;
11 * provided, however, that:
12 * 1. Any and all reproductions of the source or object code must include the
13 * copyright notice above and the following disclaimer of warranties; and
14 * 2. No rights are granted, in any manner or form, to use Whistle
15 * Communications, Inc. trademarks, including the mark "WHISTLE
16 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as
17 * such appears in the above copyright notice or in the software.
18 *
19 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
20 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
21 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
22 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
23 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
24 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
25 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
26 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
27 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
28 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
29 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
30 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
31 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
35 * OF SUCH DAMAGE.
36 *
37 * Authors: Archie Cobbs <archie@freebsd.org>
38 * Julian Elischer <julian@freebsd.org>
39 *
40 * $FreeBSD: head/sys/netgraph/ng_ether.c 63543 2000-07-19 17:33:53Z archie $
41 */
42
43/*
44 * ng_ether(4) netgraph node type
45 */
46
47#include <sys/param.h>
48#include <sys/systm.h>
49#include <sys/kernel.h>
50#include <sys/malloc.h>
51#include <sys/mbuf.h>
52#include <sys/errno.h>
53#include <sys/syslog.h>
54#include <sys/socket.h>
55
56#include <net/if.h>
57#include <net/if_types.h>
58#include <net/if_arp.h>
59#include <net/if_var.h>
60#include <net/ethernet.h>
61
62#include <netgraph/ng_message.h>
63#include <netgraph/netgraph.h>
64#include <netgraph/ng_parse.h>
65#include <netgraph/ng_ether.h>
66
67#define IFP2AC(IFP) ((struct arpcom *)IFP)
68#define IFP2NG(ifp) ((struct ng_node *)((struct arpcom *)(ifp))->ac_netgraph)
69
70/* Per-node private data */
71struct private {
72 struct ifnet *ifp; /* associated interface */
73 hook_p upper; /* upper hook connection */
74 hook_p lower; /* lower OR orphan hook connection */
75 u_char lowerOrphan; /* whether lower is lower or orphan */
76};
77typedef struct private *priv_p;
78
79/* Functional hooks called from if_ethersubr.c */
80static void ng_ether_input(struct ifnet *ifp,
81 struct mbuf **mp, struct ether_header *eh);
82static void ng_ether_input_orphan(struct ifnet *ifp,
83 struct mbuf *m, struct ether_header *eh);
84static int ng_ether_output(struct ifnet *ifp, struct mbuf **mp);
85static void ng_ether_attach(struct ifnet *ifp);
86static void ng_ether_detach(struct ifnet *ifp);
87
88/* Other functions */
89static void ng_ether_input2(node_p node,
90 struct mbuf **mp, struct ether_header *eh);
91static int ng_ether_glueback_header(struct mbuf **mp,
92 struct ether_header *eh);
93static int ng_ether_rcv_lower(node_p node, struct mbuf *m, meta_p meta);
94static int ng_ether_rcv_upper(node_p node, struct mbuf *m, meta_p meta);
95
96/* Netgraph node methods */
97static ng_constructor_t ng_ether_constructor;
98static ng_rcvmsg_t ng_ether_rcvmsg;
99static ng_shutdown_t ng_ether_rmnode;
100static ng_newhook_t ng_ether_newhook;
101static ng_rcvdata_t ng_ether_rcvdata;
102static ng_disconnect_t ng_ether_disconnect;
103static int ng_ether_mod_event(module_t mod, int event, void *data);
104
105/* List of commands and how to convert arguments to/from ASCII */
106static const struct ng_cmdlist ng_ether_cmdlist[] = {
107 {
108 NGM_ETHER_COOKIE,
109 NGM_ETHER_GET_IFNAME,
110 "getifname",
111 NULL,
112 &ng_parse_string_type
113 },
114 {
115 NGM_ETHER_COOKIE,
116 NGM_ETHER_GET_IFINDEX,
117 "getifindex",
118 NULL,
119 &ng_parse_int32_type
120 },
121 { 0 }
122};
123
124static struct ng_type ng_ether_typestruct = {
125 NG_VERSION,
126 NG_ETHER_NODE_TYPE,
127 ng_ether_mod_event,
128 ng_ether_constructor,
129 ng_ether_rcvmsg,
130 ng_ether_rmnode,
131 ng_ether_newhook,
132 NULL,
133 NULL,
134 ng_ether_rcvdata,
135 ng_ether_rcvdata,
136 ng_ether_disconnect,
137 ng_ether_cmdlist,
138};
139NETGRAPH_INIT(ether, &ng_ether_typestruct);
140
141/******************************************************************
142 ETHERNET FUNCTION HOOKS
143******************************************************************/
144
145/*
146 * Handle a packet that has come in on an interface. We get to
147 * look at it here before any upper layer protocols do.
148 *
149 * NOTE: this function will get called at splimp()
150 */
151static void
152ng_ether_input(struct ifnet *ifp,
153 struct mbuf **mp, struct ether_header *eh)
154{
155 const node_p node = IFP2NG(ifp);
156 const priv_p priv = node->private;
157
158 /* If "lower" hook not connected, let packet continue */
159 if (priv->lower == NULL || priv->lowerOrphan)
160 return;
161 ng_ether_input2(node, mp, eh);
162}
163
164/*
165 * Handle a packet that has come in on an interface, and which
166 * does not match any of our known protocols (an ``orphan'').
167 *
168 * NOTE: this function will get called at splimp()
169 */
170static void
171ng_ether_input_orphan(struct ifnet *ifp,
172 struct mbuf *m, struct ether_header *eh)
173{
174 const node_p node = IFP2NG(ifp);
175 const priv_p priv = node->private;
176
177 /* If "orphan" hook not connected, let packet continue */
178 if (priv->lower == NULL || !priv->lowerOrphan) {
179 m_freem(m);
180 return;
181 }
182 ng_ether_input2(node, &m, eh);
183 if (m != NULL)
184 m_freem(m);
185}
186
187/*
188 * Handle a packet that has come in on an interface.
189 * The Ethernet header has already been detached from the mbuf,
190 * so we have to put it back.
191 *
192 * NOTE: this function will get called at splimp()
193 */
194static void
195ng_ether_input2(node_p node, struct mbuf **mp, struct ether_header *eh)
196{
197 const priv_p priv = node->private;
198 meta_p meta = NULL;
199 int error;
200
201 /* Glue Ethernet header back on */
202 if ((error = ng_ether_glueback_header(mp, eh)) != 0)
203 return;
204
205 /* Send out lower/orphan hook */
206 (void)ng_queue_data(priv->lower, *mp, meta);
207 *mp = NULL;
208}
209
210/*
211 * Handle a packet that is going out on an interface.
212 * The Ethernet header is already attached to the mbuf.
213 */
214static int
215ng_ether_output(struct ifnet *ifp, struct mbuf **mp)
216{
217 const node_p node = IFP2NG(ifp);
218 const priv_p priv = node->private;
219 meta_p meta = NULL;
220 int error = 0;
221
222 /* If "upper" hook not connected, let packet continue */
223 if (priv->upper == NULL)
224 return (0);
225
226 /* Send it out "upper" hook */
227 NG_SEND_DATA_RET(error, priv->upper, *mp, meta);
228
229 /* If we got a reflected packet back, handle it */
230 if (error == 0 && *mp != NULL) {
231 error = ng_ether_rcv_upper(node, *mp, meta);
232 *mp = NULL;
233 }
234 return (error);
235}
236
237/*
238 * A new Ethernet interface has been attached.
239 * Create a new node for it, etc.
240 */
241static void
242ng_ether_attach(struct ifnet *ifp)
243{
244 char name[IFNAMSIZ + 1];
245 priv_p priv;
246 node_p node;
247
248 /* Create node */
249 KASSERT(!IFP2NG(ifp), ("%s: node already exists?", __FUNCTION__));
250 snprintf(name, sizeof(name), "%s%d", ifp->if_name, ifp->if_unit);
251 if (ng_make_node_common(&ng_ether_typestruct, &node) != 0) {
252 log(LOG_ERR, "%s: can't %s for %s\n",
253 __FUNCTION__, "create node", name);
254 return;
255 }
256
257 /* Allocate private data */
258 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT);
259 if (priv == NULL) {
260 log(LOG_ERR, "%s: can't %s for %s\n",
261 __FUNCTION__, "allocate memory", name);
262 ng_unref(node);
263 return;
264 }
265 bzero(priv, sizeof(*priv));
266 node->private = priv;
267 priv->ifp = ifp;
268 IFP2NG(ifp) = node;
269
270 /* Try to give the node the same name as the interface */
271 if (ng_name_node(node, name) != 0) {
272 log(LOG_WARNING, "%s: can't name node %s\n",
273 __FUNCTION__, name);
274 }
275}
276
277/*
278 * An Ethernet interface is being detached.
279 * Destroy its node.
280 */
281static void
282ng_ether_detach(struct ifnet *ifp)
283{
284 const node_p node = IFP2NG(ifp);
285 priv_p priv;
286
287 if (node == NULL) /* no node (why not?), ignore */
288 return;
289 ng_rmnode(node); /* break all links to other nodes */
290 node->flags |= NG_INVALID;
291 ng_unname(node); /* free name (and its reference) */
292 IFP2NG(ifp) = NULL; /* detach node from interface */
293 priv = node->private; /* free node private info */
294 bzero(priv, sizeof(*priv));
295 FREE(priv, M_NETGRAPH);
296 node->private = NULL;
297 ng_unref(node); /* free node itself */
298}
299
300/*
301 * Optimization for gluing the Ethernet header back onto
302 * the front of an incoming packet.
303 */
304static int
305ng_ether_glueback_header(struct mbuf **mp, struct ether_header *eh)
306{
307 struct mbuf *m = *mp;
308 uintfptr_t room;
309 int error = 0;
310
311 /*
312 * Possibly the header is already on the front.
313 * If this is the case so just move the markers back
314 * to re-include it. We lucked out.
315 * This allows us to avoid a yucky m_pullup
316 * in later nodes if it works.
317 */
318 if (eh == mtod(m, struct ether_header *) - 1) {
319 m->m_len += sizeof(*eh);
320 m->m_data -= sizeof(*eh);
321 m->m_pkthdr.len += sizeof(*eh);
322 goto done;
323 }
324
325 /*
326 * Alternatively there may be room even though
327 * it is stored somewhere else. If so, copy it in.
328 * This only safe because we KNOW that this packet has
329 * just been generated by an ethernet card, so there are
330 * no aliases to the buffer (not so for outgoing packets).
331 * Nearly all ethernet cards will end up producing mbufs
332 * that fall into these cases. So we are not optimizing
333 * contorted cases.
334 */
335 if ((m->m_flags & M_EXT) != 0) {
336 room = mtod(m, caddr_t) - m->m_ext.ext_buf;
337 if (room > m->m_ext.ext_size) /* garbage, fail immediately */
338 room = 0;
339 } else
340 room = mtod(m, caddr_t) - m->m_pktdat;
341
342 /*
343 * If we have room, just copy it and adjust
344 */
345 if (room >= sizeof(*eh)) {
346 m->m_len += sizeof(*eh);
347 m->m_data -= sizeof(*eh);
348 m->m_pkthdr.len += sizeof(*eh);
349 goto copy;
350 }
351
352 /*
353 * Doing anything more is likely to get more
354 * expensive than it's worth..
355 * it's probable that everything else is in one
356 * big lump. The next node will do an m_pullup()
357 * for exactly the amount of data it needs and
358 * hopefully everything after that will not
359 * need one. So let's just use M_PREPEND.
360 */
361 M_PREPEND(m, sizeof (*eh), M_DONTWAIT);
362 if (m == NULL) {
363 error = ENOBUFS;
364 goto done;
365 }
366
367copy:
368 /* Copy header and return (possibly new) mbuf */
369 bcopy((caddr_t)eh, mtod(m, struct ether_header *), sizeof(*eh));
370done:
371 *mp = m;
372 return error;
373}
374
375/******************************************************************
376 NETGRAPH NODE METHODS
377******************************************************************/
378
379/*
380 * It is not possible or allowable to create a node of this type.
381 * Nodes get created when the interface is attached (or, when
382 * this node type's KLD is loaded).
383 */
384static int
385ng_ether_constructor(node_p *nodep)
386{
387 return (EINVAL);
388}
389
390/*
391 * Check for attaching a new hook.
392 */
393static int
394ng_ether_newhook(node_p node, hook_p hook, const char *name)
395{
396 const priv_p priv = node->private;
397 u_char orphan = priv->lowerOrphan;
398 hook_p *hookptr;
399
400 /* Divert hook is an alias for lower */
401 if (strcmp(name, NG_ETHER_HOOK_DIVERT) == 0)
402 name = NG_ETHER_HOOK_LOWER;
403
404 /* Which hook? */
405 if (strcmp(name, NG_ETHER_HOOK_UPPER) == 0)
406 hookptr = &priv->upper;
407 else if (strcmp(name, NG_ETHER_HOOK_LOWER) == 0) {
408 hookptr = &priv->lower;
409 orphan = 0;
410 } else if (strcmp(name, NG_ETHER_HOOK_ORPHAN) == 0) {
411 hookptr = &priv->lower;
412 orphan = 1;
413 } else
414 return (EINVAL);
415
416 /* Check if already connected (shouldn't be, but doesn't hurt) */
417 if (*hookptr != NULL)
418 return (EISCONN);
419
420 /* OK */
421 *hookptr = hook;
422 priv->lowerOrphan = orphan;
423 return (0);
424}
425
426/*
427 * Receive an incoming control message.
428 */
429static int
430ng_ether_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
431 struct ng_mesg **rptr, hook_p lasthook)
432{
433 const priv_p priv = node->private;
434 struct ng_mesg *resp = NULL;
435 int error = 0;
436
437 switch (msg->header.typecookie) {
438 case NGM_ETHER_COOKIE:
439 switch (msg->header.cmd) {
440 case NGM_ETHER_GET_IFNAME:
441 NG_MKRESPONSE(resp, msg, IFNAMSIZ + 1, M_NOWAIT);
442 if (resp == NULL) {
443 error = ENOMEM;
444 break;
445 }
446 snprintf(resp->data, IFNAMSIZ + 1,
447 "%s%d", priv->ifp->if_name, priv->ifp->if_unit);
448 break;
449 case NGM_ETHER_GET_IFINDEX:
450 NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
451 if (resp == NULL) {
452 error = ENOMEM;
453 break;
454 }
455 *((u_int32_t *)resp->data) = priv->ifp->if_index;
456 break;
457 default:
458 error = EINVAL;
459 break;
460 }
461 break;
462 default:
463 error = EINVAL;
464 break;
465 }
466 if (rptr)
467 *rptr = resp;
468 else if (resp != NULL)
469 FREE(resp, M_NETGRAPH);
470 FREE(msg, M_NETGRAPH);
471 return (error);
472}
473
474/*
475 * Receive data on a hook.
476 */
477static int
478ng_ether_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
479 struct mbuf **ret_m, meta_p *ret_meta)
480{
481 const node_p node = hook->node;
482 const priv_p priv = node->private;
483
484 if (hook == priv->lower)
485 return ng_ether_rcv_lower(node, m, meta);
486 if (hook == priv->upper)
487 return ng_ether_rcv_upper(node, m, meta);
488 panic("%s: weird hook", __FUNCTION__);
489}
490
491/*
492 * Handle an mbuf received on the "lower" hook.
493 */
494static int
495ng_ether_rcv_lower(node_p node, struct mbuf *m, meta_p meta)
496{
497 const priv_p priv = node->private;
498 struct ether_header *eh;
499
500 /* Make sure header is fully pulled up */
501 if (m->m_pkthdr.len < sizeof(struct ether_header)) {
502 NG_FREE_DATA(m, meta);
503 return (EINVAL);
504 }
505 if (m->m_len < sizeof(struct ether_header)
506 && (m = m_pullup(m, sizeof(struct ether_header))) == NULL) {
507 NG_FREE_META(meta);
508 return (ENOBUFS);
509 }
510
511 /* drop in the MAC address */
512 eh = mtod(m, struct ether_header *);
513 bcopy((IFP2AC(priv->ifp))->ac_enaddr, eh->ether_shost, 6);
514
515 /* Send it on its way */
516 NG_FREE_META(meta);
517 return ether_output_frame(priv->ifp, m);
518}
519
520/*
521 * Handle an mbuf received on the "upper" hook.
522 */
523static int
524ng_ether_rcv_upper(node_p node, struct mbuf *m, meta_p meta)
525{
526 const priv_p priv = node->private;
527 struct ether_header *eh;
528
529 /* Check length and pull off header */
530 if (m->m_pkthdr.len < sizeof(*eh)) {
531 NG_FREE_DATA(m, meta);
532 return (EINVAL);
533 }
534 if (m->m_len < sizeof(*eh) && (m = m_pullup(m, sizeof(*eh))) == NULL) {
535 NG_FREE_META(meta);
536 return (ENOBUFS);
537 }
538 eh = mtod(m, struct ether_header *);
539 m->m_data += sizeof(*eh);
540 m->m_len -= sizeof(*eh);
541 m->m_pkthdr.len -= sizeof(*eh);
542
543 /* Route packet back in */
544 NG_FREE_META(meta);
545 ether_demux(priv->ifp, eh, m);
546 return (0);
547}
548
549/*
550 * Shutdown node. This resets the node but does not remove it.
551 */
552static int
553ng_ether_rmnode(node_p node)
554{
555 ng_cutlinks(node);
556 node->flags &= ~NG_INVALID; /* bounce back to life */
557 return (0);
558}
559
560/*
561 * Hook disconnection.
562 */
563static int
564ng_ether_disconnect(hook_p hook)
565{
566 const priv_p priv = hook->node->private;
567
568 if (hook == priv->upper)
569 priv->upper = NULL;
570 else if (hook == priv->lower) {
571 priv->lower = NULL;
572 priv->lowerOrphan = 0;
573 } else
574 panic("%s: weird hook", __FUNCTION__);
575 return (0);
576}
577
578/******************************************************************
579 INITIALIZATION
580******************************************************************/
581
582/*
583 * Handle loading and unloading for this node type.
584 */
585static int
586ng_ether_mod_event(module_t mod, int event, void *data)
587{
588 struct ifnet *ifp;
589 int error = 0;
590 int s;
591
592 s = splnet();
593 switch (event) {
594 case MOD_LOAD:
595
596 /* Register function hooks */
597 if (ng_ether_attach_p != NULL) {
598 error = EEXIST;
599 break;
600 }
601 ng_ether_attach_p = ng_ether_attach;
602 ng_ether_detach_p = ng_ether_detach;
603 ng_ether_output_p = ng_ether_output;
604 ng_ether_input_p = ng_ether_input;
605 ng_ether_input_orphan_p = ng_ether_input_orphan;
606
607 /* Create nodes for any already-existing Ethernet interfaces */
608 TAILQ_FOREACH(ifp, &ifnet, if_link) {
609 if (ifp->if_type == IFT_ETHER)
610 ng_ether_attach(ifp);
611 }
612 break;
613
614 case MOD_UNLOAD:
615
616 /*
617 * Note that the base code won't try to unload us until
618 * all nodes have been removed, and that can't happen
619 * until all Ethernet interfaces are removed. In any
620 * case, we know there are no nodes left if the action
621 * is MOD_UNLOAD, so there's no need to detach any nodes.
622 */
623
624 /* Unregister function hooks */
625 ng_ether_attach_p = NULL;
626 ng_ether_detach_p = NULL;
627 ng_ether_output_p = NULL;
628 ng_ether_input_p = NULL;
629 ng_ether_input_orphan_p = NULL;
630 break;
631
632 default:
633 error = EOPNOTSUPP;
634 break;
635 }
636 splx(s);
637 return (error);
638}
639
2/*
3 * ng_ether.c
4 *
5 * Copyright (c) 1996-2000 Whistle Communications, Inc.
6 * All rights reserved.
7 *
8 * Subject to the following obligations and disclaimer of warranty, use and
9 * redistribution of this software, in source or object code forms, with or
10 * without modifications are expressly permitted by Whistle Communications;
11 * provided, however, that:
12 * 1. Any and all reproductions of the source or object code must include the
13 * copyright notice above and the following disclaimer of warranties; and
14 * 2. No rights are granted, in any manner or form, to use Whistle
15 * Communications, Inc. trademarks, including the mark "WHISTLE
16 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as
17 * such appears in the above copyright notice or in the software.
18 *
19 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
20 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
21 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
22 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
23 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
24 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
25 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
26 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
27 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
28 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
29 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
30 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
31 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
35 * OF SUCH DAMAGE.
36 *
37 * Authors: Archie Cobbs <archie@freebsd.org>
38 * Julian Elischer <julian@freebsd.org>
39 *
40 * $FreeBSD: head/sys/netgraph/ng_ether.c 63543 2000-07-19 17:33:53Z archie $
41 */
42
43/*
44 * ng_ether(4) netgraph node type
45 */
46
47#include <sys/param.h>
48#include <sys/systm.h>
49#include <sys/kernel.h>
50#include <sys/malloc.h>
51#include <sys/mbuf.h>
52#include <sys/errno.h>
53#include <sys/syslog.h>
54#include <sys/socket.h>
55
56#include <net/if.h>
57#include <net/if_types.h>
58#include <net/if_arp.h>
59#include <net/if_var.h>
60#include <net/ethernet.h>
61
62#include <netgraph/ng_message.h>
63#include <netgraph/netgraph.h>
64#include <netgraph/ng_parse.h>
65#include <netgraph/ng_ether.h>
66
67#define IFP2AC(IFP) ((struct arpcom *)IFP)
68#define IFP2NG(ifp) ((struct ng_node *)((struct arpcom *)(ifp))->ac_netgraph)
69
70/* Per-node private data */
71struct private {
72 struct ifnet *ifp; /* associated interface */
73 hook_p upper; /* upper hook connection */
74 hook_p lower; /* lower OR orphan hook connection */
75 u_char lowerOrphan; /* whether lower is lower or orphan */
76};
77typedef struct private *priv_p;
78
79/* Functional hooks called from if_ethersubr.c */
80static void ng_ether_input(struct ifnet *ifp,
81 struct mbuf **mp, struct ether_header *eh);
82static void ng_ether_input_orphan(struct ifnet *ifp,
83 struct mbuf *m, struct ether_header *eh);
84static int ng_ether_output(struct ifnet *ifp, struct mbuf **mp);
85static void ng_ether_attach(struct ifnet *ifp);
86static void ng_ether_detach(struct ifnet *ifp);
87
88/* Other functions */
89static void ng_ether_input2(node_p node,
90 struct mbuf **mp, struct ether_header *eh);
91static int ng_ether_glueback_header(struct mbuf **mp,
92 struct ether_header *eh);
93static int ng_ether_rcv_lower(node_p node, struct mbuf *m, meta_p meta);
94static int ng_ether_rcv_upper(node_p node, struct mbuf *m, meta_p meta);
95
96/* Netgraph node methods */
97static ng_constructor_t ng_ether_constructor;
98static ng_rcvmsg_t ng_ether_rcvmsg;
99static ng_shutdown_t ng_ether_rmnode;
100static ng_newhook_t ng_ether_newhook;
101static ng_rcvdata_t ng_ether_rcvdata;
102static ng_disconnect_t ng_ether_disconnect;
103static int ng_ether_mod_event(module_t mod, int event, void *data);
104
105/* List of commands and how to convert arguments to/from ASCII */
106static const struct ng_cmdlist ng_ether_cmdlist[] = {
107 {
108 NGM_ETHER_COOKIE,
109 NGM_ETHER_GET_IFNAME,
110 "getifname",
111 NULL,
112 &ng_parse_string_type
113 },
114 {
115 NGM_ETHER_COOKIE,
116 NGM_ETHER_GET_IFINDEX,
117 "getifindex",
118 NULL,
119 &ng_parse_int32_type
120 },
121 { 0 }
122};
123
124static struct ng_type ng_ether_typestruct = {
125 NG_VERSION,
126 NG_ETHER_NODE_TYPE,
127 ng_ether_mod_event,
128 ng_ether_constructor,
129 ng_ether_rcvmsg,
130 ng_ether_rmnode,
131 ng_ether_newhook,
132 NULL,
133 NULL,
134 ng_ether_rcvdata,
135 ng_ether_rcvdata,
136 ng_ether_disconnect,
137 ng_ether_cmdlist,
138};
139NETGRAPH_INIT(ether, &ng_ether_typestruct);
140
141/******************************************************************
142 ETHERNET FUNCTION HOOKS
143******************************************************************/
144
145/*
146 * Handle a packet that has come in on an interface. We get to
147 * look at it here before any upper layer protocols do.
148 *
149 * NOTE: this function will get called at splimp()
150 */
151static void
152ng_ether_input(struct ifnet *ifp,
153 struct mbuf **mp, struct ether_header *eh)
154{
155 const node_p node = IFP2NG(ifp);
156 const priv_p priv = node->private;
157
158 /* If "lower" hook not connected, let packet continue */
159 if (priv->lower == NULL || priv->lowerOrphan)
160 return;
161 ng_ether_input2(node, mp, eh);
162}
163
164/*
165 * Handle a packet that has come in on an interface, and which
166 * does not match any of our known protocols (an ``orphan'').
167 *
168 * NOTE: this function will get called at splimp()
169 */
170static void
171ng_ether_input_orphan(struct ifnet *ifp,
172 struct mbuf *m, struct ether_header *eh)
173{
174 const node_p node = IFP2NG(ifp);
175 const priv_p priv = node->private;
176
177 /* If "orphan" hook not connected, let packet continue */
178 if (priv->lower == NULL || !priv->lowerOrphan) {
179 m_freem(m);
180 return;
181 }
182 ng_ether_input2(node, &m, eh);
183 if (m != NULL)
184 m_freem(m);
185}
186
187/*
188 * Handle a packet that has come in on an interface.
189 * The Ethernet header has already been detached from the mbuf,
190 * so we have to put it back.
191 *
192 * NOTE: this function will get called at splimp()
193 */
194static void
195ng_ether_input2(node_p node, struct mbuf **mp, struct ether_header *eh)
196{
197 const priv_p priv = node->private;
198 meta_p meta = NULL;
199 int error;
200
201 /* Glue Ethernet header back on */
202 if ((error = ng_ether_glueback_header(mp, eh)) != 0)
203 return;
204
205 /* Send out lower/orphan hook */
206 (void)ng_queue_data(priv->lower, *mp, meta);
207 *mp = NULL;
208}
209
210/*
211 * Handle a packet that is going out on an interface.
212 * The Ethernet header is already attached to the mbuf.
213 */
214static int
215ng_ether_output(struct ifnet *ifp, struct mbuf **mp)
216{
217 const node_p node = IFP2NG(ifp);
218 const priv_p priv = node->private;
219 meta_p meta = NULL;
220 int error = 0;
221
222 /* If "upper" hook not connected, let packet continue */
223 if (priv->upper == NULL)
224 return (0);
225
226 /* Send it out "upper" hook */
227 NG_SEND_DATA_RET(error, priv->upper, *mp, meta);
228
229 /* If we got a reflected packet back, handle it */
230 if (error == 0 && *mp != NULL) {
231 error = ng_ether_rcv_upper(node, *mp, meta);
232 *mp = NULL;
233 }
234 return (error);
235}
236
237/*
238 * A new Ethernet interface has been attached.
239 * Create a new node for it, etc.
240 */
241static void
242ng_ether_attach(struct ifnet *ifp)
243{
244 char name[IFNAMSIZ + 1];
245 priv_p priv;
246 node_p node;
247
248 /* Create node */
249 KASSERT(!IFP2NG(ifp), ("%s: node already exists?", __FUNCTION__));
250 snprintf(name, sizeof(name), "%s%d", ifp->if_name, ifp->if_unit);
251 if (ng_make_node_common(&ng_ether_typestruct, &node) != 0) {
252 log(LOG_ERR, "%s: can't %s for %s\n",
253 __FUNCTION__, "create node", name);
254 return;
255 }
256
257 /* Allocate private data */
258 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT);
259 if (priv == NULL) {
260 log(LOG_ERR, "%s: can't %s for %s\n",
261 __FUNCTION__, "allocate memory", name);
262 ng_unref(node);
263 return;
264 }
265 bzero(priv, sizeof(*priv));
266 node->private = priv;
267 priv->ifp = ifp;
268 IFP2NG(ifp) = node;
269
270 /* Try to give the node the same name as the interface */
271 if (ng_name_node(node, name) != 0) {
272 log(LOG_WARNING, "%s: can't name node %s\n",
273 __FUNCTION__, name);
274 }
275}
276
277/*
278 * An Ethernet interface is being detached.
279 * Destroy its node.
280 */
281static void
282ng_ether_detach(struct ifnet *ifp)
283{
284 const node_p node = IFP2NG(ifp);
285 priv_p priv;
286
287 if (node == NULL) /* no node (why not?), ignore */
288 return;
289 ng_rmnode(node); /* break all links to other nodes */
290 node->flags |= NG_INVALID;
291 ng_unname(node); /* free name (and its reference) */
292 IFP2NG(ifp) = NULL; /* detach node from interface */
293 priv = node->private; /* free node private info */
294 bzero(priv, sizeof(*priv));
295 FREE(priv, M_NETGRAPH);
296 node->private = NULL;
297 ng_unref(node); /* free node itself */
298}
299
300/*
301 * Optimization for gluing the Ethernet header back onto
302 * the front of an incoming packet.
303 */
304static int
305ng_ether_glueback_header(struct mbuf **mp, struct ether_header *eh)
306{
307 struct mbuf *m = *mp;
308 uintfptr_t room;
309 int error = 0;
310
311 /*
312 * Possibly the header is already on the front.
313 * If this is the case so just move the markers back
314 * to re-include it. We lucked out.
315 * This allows us to avoid a yucky m_pullup
316 * in later nodes if it works.
317 */
318 if (eh == mtod(m, struct ether_header *) - 1) {
319 m->m_len += sizeof(*eh);
320 m->m_data -= sizeof(*eh);
321 m->m_pkthdr.len += sizeof(*eh);
322 goto done;
323 }
324
325 /*
326 * Alternatively there may be room even though
327 * it is stored somewhere else. If so, copy it in.
328 * This only safe because we KNOW that this packet has
329 * just been generated by an ethernet card, so there are
330 * no aliases to the buffer (not so for outgoing packets).
331 * Nearly all ethernet cards will end up producing mbufs
332 * that fall into these cases. So we are not optimizing
333 * contorted cases.
334 */
335 if ((m->m_flags & M_EXT) != 0) {
336 room = mtod(m, caddr_t) - m->m_ext.ext_buf;
337 if (room > m->m_ext.ext_size) /* garbage, fail immediately */
338 room = 0;
339 } else
340 room = mtod(m, caddr_t) - m->m_pktdat;
341
342 /*
343 * If we have room, just copy it and adjust
344 */
345 if (room >= sizeof(*eh)) {
346 m->m_len += sizeof(*eh);
347 m->m_data -= sizeof(*eh);
348 m->m_pkthdr.len += sizeof(*eh);
349 goto copy;
350 }
351
352 /*
353 * Doing anything more is likely to get more
354 * expensive than it's worth..
355 * it's probable that everything else is in one
356 * big lump. The next node will do an m_pullup()
357 * for exactly the amount of data it needs and
358 * hopefully everything after that will not
359 * need one. So let's just use M_PREPEND.
360 */
361 M_PREPEND(m, sizeof (*eh), M_DONTWAIT);
362 if (m == NULL) {
363 error = ENOBUFS;
364 goto done;
365 }
366
367copy:
368 /* Copy header and return (possibly new) mbuf */
369 bcopy((caddr_t)eh, mtod(m, struct ether_header *), sizeof(*eh));
370done:
371 *mp = m;
372 return error;
373}
374
375/******************************************************************
376 NETGRAPH NODE METHODS
377******************************************************************/
378
379/*
380 * It is not possible or allowable to create a node of this type.
381 * Nodes get created when the interface is attached (or, when
382 * this node type's KLD is loaded).
383 */
384static int
385ng_ether_constructor(node_p *nodep)
386{
387 return (EINVAL);
388}
389
390/*
391 * Check for attaching a new hook.
392 */
393static int
394ng_ether_newhook(node_p node, hook_p hook, const char *name)
395{
396 const priv_p priv = node->private;
397 u_char orphan = priv->lowerOrphan;
398 hook_p *hookptr;
399
400 /* Divert hook is an alias for lower */
401 if (strcmp(name, NG_ETHER_HOOK_DIVERT) == 0)
402 name = NG_ETHER_HOOK_LOWER;
403
404 /* Which hook? */
405 if (strcmp(name, NG_ETHER_HOOK_UPPER) == 0)
406 hookptr = &priv->upper;
407 else if (strcmp(name, NG_ETHER_HOOK_LOWER) == 0) {
408 hookptr = &priv->lower;
409 orphan = 0;
410 } else if (strcmp(name, NG_ETHER_HOOK_ORPHAN) == 0) {
411 hookptr = &priv->lower;
412 orphan = 1;
413 } else
414 return (EINVAL);
415
416 /* Check if already connected (shouldn't be, but doesn't hurt) */
417 if (*hookptr != NULL)
418 return (EISCONN);
419
420 /* OK */
421 *hookptr = hook;
422 priv->lowerOrphan = orphan;
423 return (0);
424}
425
426/*
427 * Receive an incoming control message.
428 */
429static int
430ng_ether_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
431 struct ng_mesg **rptr, hook_p lasthook)
432{
433 const priv_p priv = node->private;
434 struct ng_mesg *resp = NULL;
435 int error = 0;
436
437 switch (msg->header.typecookie) {
438 case NGM_ETHER_COOKIE:
439 switch (msg->header.cmd) {
440 case NGM_ETHER_GET_IFNAME:
441 NG_MKRESPONSE(resp, msg, IFNAMSIZ + 1, M_NOWAIT);
442 if (resp == NULL) {
443 error = ENOMEM;
444 break;
445 }
446 snprintf(resp->data, IFNAMSIZ + 1,
447 "%s%d", priv->ifp->if_name, priv->ifp->if_unit);
448 break;
449 case NGM_ETHER_GET_IFINDEX:
450 NG_MKRESPONSE(resp, msg, sizeof(u_int32_t), M_NOWAIT);
451 if (resp == NULL) {
452 error = ENOMEM;
453 break;
454 }
455 *((u_int32_t *)resp->data) = priv->ifp->if_index;
456 break;
457 default:
458 error = EINVAL;
459 break;
460 }
461 break;
462 default:
463 error = EINVAL;
464 break;
465 }
466 if (rptr)
467 *rptr = resp;
468 else if (resp != NULL)
469 FREE(resp, M_NETGRAPH);
470 FREE(msg, M_NETGRAPH);
471 return (error);
472}
473
474/*
475 * Receive data on a hook.
476 */
477static int
478ng_ether_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
479 struct mbuf **ret_m, meta_p *ret_meta)
480{
481 const node_p node = hook->node;
482 const priv_p priv = node->private;
483
484 if (hook == priv->lower)
485 return ng_ether_rcv_lower(node, m, meta);
486 if (hook == priv->upper)
487 return ng_ether_rcv_upper(node, m, meta);
488 panic("%s: weird hook", __FUNCTION__);
489}
490
491/*
492 * Handle an mbuf received on the "lower" hook.
493 */
494static int
495ng_ether_rcv_lower(node_p node, struct mbuf *m, meta_p meta)
496{
497 const priv_p priv = node->private;
498 struct ether_header *eh;
499
500 /* Make sure header is fully pulled up */
501 if (m->m_pkthdr.len < sizeof(struct ether_header)) {
502 NG_FREE_DATA(m, meta);
503 return (EINVAL);
504 }
505 if (m->m_len < sizeof(struct ether_header)
506 && (m = m_pullup(m, sizeof(struct ether_header))) == NULL) {
507 NG_FREE_META(meta);
508 return (ENOBUFS);
509 }
510
511 /* drop in the MAC address */
512 eh = mtod(m, struct ether_header *);
513 bcopy((IFP2AC(priv->ifp))->ac_enaddr, eh->ether_shost, 6);
514
515 /* Send it on its way */
516 NG_FREE_META(meta);
517 return ether_output_frame(priv->ifp, m);
518}
519
520/*
521 * Handle an mbuf received on the "upper" hook.
522 */
523static int
524ng_ether_rcv_upper(node_p node, struct mbuf *m, meta_p meta)
525{
526 const priv_p priv = node->private;
527 struct ether_header *eh;
528
529 /* Check length and pull off header */
530 if (m->m_pkthdr.len < sizeof(*eh)) {
531 NG_FREE_DATA(m, meta);
532 return (EINVAL);
533 }
534 if (m->m_len < sizeof(*eh) && (m = m_pullup(m, sizeof(*eh))) == NULL) {
535 NG_FREE_META(meta);
536 return (ENOBUFS);
537 }
538 eh = mtod(m, struct ether_header *);
539 m->m_data += sizeof(*eh);
540 m->m_len -= sizeof(*eh);
541 m->m_pkthdr.len -= sizeof(*eh);
542
543 /* Route packet back in */
544 NG_FREE_META(meta);
545 ether_demux(priv->ifp, eh, m);
546 return (0);
547}
548
549/*
550 * Shutdown node. This resets the node but does not remove it.
551 */
552static int
553ng_ether_rmnode(node_p node)
554{
555 ng_cutlinks(node);
556 node->flags &= ~NG_INVALID; /* bounce back to life */
557 return (0);
558}
559
560/*
561 * Hook disconnection.
562 */
563static int
564ng_ether_disconnect(hook_p hook)
565{
566 const priv_p priv = hook->node->private;
567
568 if (hook == priv->upper)
569 priv->upper = NULL;
570 else if (hook == priv->lower) {
571 priv->lower = NULL;
572 priv->lowerOrphan = 0;
573 } else
574 panic("%s: weird hook", __FUNCTION__);
575 return (0);
576}
577
578/******************************************************************
579 INITIALIZATION
580******************************************************************/
581
582/*
583 * Handle loading and unloading for this node type.
584 */
585static int
586ng_ether_mod_event(module_t mod, int event, void *data)
587{
588 struct ifnet *ifp;
589 int error = 0;
590 int s;
591
592 s = splnet();
593 switch (event) {
594 case MOD_LOAD:
595
596 /* Register function hooks */
597 if (ng_ether_attach_p != NULL) {
598 error = EEXIST;
599 break;
600 }
601 ng_ether_attach_p = ng_ether_attach;
602 ng_ether_detach_p = ng_ether_detach;
603 ng_ether_output_p = ng_ether_output;
604 ng_ether_input_p = ng_ether_input;
605 ng_ether_input_orphan_p = ng_ether_input_orphan;
606
607 /* Create nodes for any already-existing Ethernet interfaces */
608 TAILQ_FOREACH(ifp, &ifnet, if_link) {
609 if (ifp->if_type == IFT_ETHER)
610 ng_ether_attach(ifp);
611 }
612 break;
613
614 case MOD_UNLOAD:
615
616 /*
617 * Note that the base code won't try to unload us until
618 * all nodes have been removed, and that can't happen
619 * until all Ethernet interfaces are removed. In any
620 * case, we know there are no nodes left if the action
621 * is MOD_UNLOAD, so there's no need to detach any nodes.
622 */
623
624 /* Unregister function hooks */
625 ng_ether_attach_p = NULL;
626 ng_ether_detach_p = NULL;
627 ng_ether_output_p = NULL;
628 ng_ether_input_p = NULL;
629 ng_ether_input_orphan_p = NULL;
630 break;
631
632 default:
633 error = EOPNOTSUPP;
634 break;
635 }
636 splx(s);
637 return (error);
638}
639