xref: /dragonfly/sys/netgraph/pppoe/ng_pppoe.c (revision b7367ef6)
1 
2 /*
3  * ng_pppoe.c
4  *
5  * Copyright (c) 1996-1999 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  * Author: Julian Elischer <julian@freebsd.org>
38  *
39  * $FreeBSD: src/sys/netgraph/ng_pppoe.c,v 1.23.2.17 2002/07/02 22:17:18 archie Exp $
40  * $DragonFly: src/sys/netgraph/pppoe/ng_pppoe.c,v 1.10 2007/06/03 20:51:13 dillon Exp $
41  * $Whistle: ng_pppoe.c,v 1.10 1999/11/01 09:24:52 julian Exp $
42  */
43 #if 0
44 #define AAA kprintf("pppoe: %s\n", __func__ );
45 #define BBB kprintf("-%d-", __LINE__ );
46 #else
47 #define AAA
48 #define BBB
49 #endif
50 
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/kernel.h>
54 #include <sys/mbuf.h>
55 #include <sys/malloc.h>
56 #include <sys/errno.h>
57 #include <sys/sysctl.h>
58 #include <sys/syslog.h>
59 #include <sys/thread2.h>
60 #include <net/ethernet.h>
61 
62 #include <netgraph/ng_message.h>
63 #include <netgraph/netgraph.h>
64 #include "ng_pppoe.h"
65 
66 #define SIGNOFF "session closed"
67 
68 /*
69  * This section contains the netgraph method declarations for the
70  * pppoe node. These methods define the netgraph pppoe 'type'.
71  */
72 
73 static ng_constructor_t	ng_pppoe_constructor;
74 static ng_rcvmsg_t	ng_pppoe_rcvmsg;
75 static ng_shutdown_t	ng_pppoe_rmnode;
76 static ng_newhook_t	ng_pppoe_newhook;
77 static ng_connect_t	ng_pppoe_connect;
78 static ng_rcvdata_t	ng_pppoe_rcvdata;
79 static ng_disconnect_t	ng_pppoe_disconnect;
80 
81 /* Netgraph node type descriptor */
82 static struct ng_type typestruct = {
83 	NG_VERSION,
84 	NG_PPPOE_NODE_TYPE,
85 	NULL,
86 	ng_pppoe_constructor,
87 	ng_pppoe_rcvmsg,
88 	ng_pppoe_rmnode,
89 	ng_pppoe_newhook,
90 	NULL,
91 	ng_pppoe_connect,
92 	ng_pppoe_rcvdata,
93 	ng_pppoe_rcvdata,
94 	ng_pppoe_disconnect,
95 	NULL
96 };
97 NETGRAPH_INIT(pppoe, &typestruct);
98 
99 /*
100  * States for the session state machine.
101  * These have no meaning if there is no hook attached yet.
102  */
103 enum state {
104     PPPOE_SNONE=0,	/* [both] Initial state */
105     PPPOE_LISTENING,	/* [Daemon] Listening for discover initiation pkt */
106     PPPOE_SINIT,	/* [Client] Sent discovery initiation */
107     PPPOE_PRIMED,	/* [Server] Awaiting PADI from daemon */
108     PPPOE_SOFFER,	/* [Server] Sent offer message  (got PADI)*/
109     PPPOE_SREQ,		/* [Client] Sent a Request */
110     PPPOE_NEWCONNECTED,	/* [Server] Connection established, No data received */
111     PPPOE_CONNECTED,	/* [Both] Connection established, Data received */
112     PPPOE_DEAD		/* [Both] */
113 };
114 
115 #define NUMTAGS 20 /* number of tags we are set up to work with */
116 
117 /*
118  * Information we store for each hook on each node for negotiating the
119  * session. The mbuf and cluster are freed once negotiation has completed.
120  * The whole negotiation block is then discarded.
121  */
122 
123 struct sess_neg {
124 	struct mbuf 		*m; /* holds cluster with last sent packet */
125 	union	packet		*pkt; /* points within the above cluster */
126 	struct callout		timeout_ch;
127 	u_int			timeout; /* 0,1,2,4,8,16 etc. seconds */
128 	u_int			numtags;
129 	const struct pppoe_tag	*tags[NUMTAGS];
130 	u_int			service_len;
131 	u_int			ac_name_len;
132 
133 	struct datatag		service;
134 	struct datatag		ac_name;
135 };
136 typedef struct sess_neg *negp;
137 
138 /*
139  * Session information that is needed after connection.
140  */
141 struct sess_con {
142 	hook_p  		hook;
143 	u_int16_t		Session_ID;
144 	enum state		state;
145 	char			creator[NG_NODESIZ]; /* who to notify */
146 	struct pppoe_full_hdr	pkt_hdr;	/* used when connected */
147 	negp			neg;		/* used when negotiating */
148 	/*struct sess_con	*hash_next;*/	/* not yet used */
149 };
150 typedef struct sess_con *sessp;
151 
152 /*
153  * Information we store for each node
154  */
155 struct PPPOE {
156 	node_p		node;		/* back pointer to node */
157 	hook_p  	ethernet_hook;
158 	hook_p  	debug_hook;
159 	u_int   	packets_in;	/* packets in from ethernet */
160 	u_int   	packets_out;	/* packets out towards ethernet */
161 	u_int32_t	flags;
162 	/*struct sess_con *buckets[HASH_SIZE];*/	/* not yet used */
163 };
164 typedef struct PPPOE *priv_p;
165 
166 struct ether_header eh_prototype =
167 	{{0xff,0xff,0xff,0xff,0xff,0xff},
168 	 {0x00,0x00,0x00,0x00,0x00,0x00},
169 	 ETHERTYPE_PPPOE_DISC};
170 
171 #define PPPOE_KEEPSTANDARD	-1	/* never switch to nonstandard mode */
172 #define PPPOE_STANDARD		0	/* try standard mode (dangerous!) */
173 #define PPPOE_NONSTANDARD	1	/* just be in nonstandard mode */
174 static int pppoe_mode = PPPOE_KEEPSTANDARD;
175 
176 static int
177 ngpppoe_set_ethertype(SYSCTL_HANDLER_ARGS)
178 {
179 	int error;
180 	int val;
181 
182 	val = pppoe_mode;
183 	error = sysctl_handle_int(oidp, &val, sizeof(int), req);
184 	if (error != 0 || req->newptr == NULL)
185 		return (error);
186 	switch (val) {
187 	case PPPOE_NONSTANDARD:
188 		pppoe_mode = PPPOE_NONSTANDARD;
189 		eh_prototype.ether_type = ETHERTYPE_PPPOE_STUPID_DISC;
190 		break;
191 	case PPPOE_STANDARD:
192 		pppoe_mode = PPPOE_STANDARD;
193 		eh_prototype.ether_type = ETHERTYPE_PPPOE_DISC;
194 		break;
195 	case PPPOE_KEEPSTANDARD:
196 		pppoe_mode = PPPOE_KEEPSTANDARD;
197 		eh_prototype.ether_type = ETHERTYPE_PPPOE_DISC;
198 		break;
199 	default:
200 		return (EINVAL);
201 	}
202 	return (0);
203 }
204 
205 SYSCTL_PROC(_net_graph, OID_AUTO, nonstandard_pppoe, CTLTYPE_INT | CTLFLAG_RW,
206     0, sizeof(int), ngpppoe_set_ethertype, "I", "nonstandard ethertype");
207 
208 union uniq {
209 	char bytes[sizeof(void *)];
210 	void * pointer;
211 	};
212 
213 #define	LEAVE(x) do { error = x; goto quit; } while(0)
214 static void	pppoe_start(sessp sp);
215 static void	sendpacket(sessp sp);
216 static void	pppoe_ticker(void *arg);
217 static const	struct pppoe_tag *scan_tags(sessp sp,
218 			const struct pppoe_hdr* ph);
219 static	int	pppoe_send_event(sessp sp, enum cmd cmdid);
220 
221 /*************************************************************************
222  * Some basic utilities  from the Linux version with author's permission.*
223  * Author:	Michal Ostrowski <mostrows@styx.uwaterloo.ca>		 *
224  ************************************************************************/
225 
226 /*
227  * Generate a new session id
228  * XXX find out the FreeBSD locking scheme.
229  */
230 static u_int16_t
231 get_new_sid(node_p node)
232 {
233 	static int pppoe_sid = 10;
234 	sessp sp;
235 	hook_p	hook;
236 	u_int16_t val;
237 	priv_p privp = node->private;
238 
239 AAA
240 restart:
241 	val = pppoe_sid++;
242 	/*
243 	 * Spec says 0xFFFF is reserved.
244 	 * Also don't use 0x0000
245 	 */
246 	if (val == 0xffff) {
247 		pppoe_sid = 20;
248 		goto restart;
249 	}
250 
251 	/* Check it isn't already in use */
252 	LIST_FOREACH(hook, &node->hooks, hooks) {
253 		/* don't check special hooks */
254 		if ((hook->private == &privp->debug_hook)
255 		||  (hook->private == &privp->ethernet_hook))
256 			continue;
257 		sp = hook->private;
258 		if (sp->Session_ID == val)
259 			goto restart;
260 	}
261 
262 	return val;
263 }
264 
265 
266 /*
267  * Return the location where the next tag can be put
268  */
269 static __inline const struct pppoe_tag*
270 next_tag(const struct pppoe_hdr* ph)
271 {
272 	return (const struct pppoe_tag*)(((const char*)&ph->tag[0])
273 	    + ntohs(ph->length));
274 }
275 
276 /*
277  * Look for a tag of a specific type
278  * Don't trust any length the other end says.
279  * but assume we already sanity checked ph->length.
280  */
281 static const struct pppoe_tag*
282 get_tag(const struct pppoe_hdr* ph, u_int16_t idx)
283 {
284 	const char *const end = (const char *)next_tag(ph);
285 	const char *ptn;
286 	const struct pppoe_tag *pt = &ph->tag[0];
287 	/*
288 	 * Keep processing tags while a tag header will still fit.
289 	 */
290 AAA
291 	while((const char*)(pt + 1) <= end) {
292 	    /*
293 	     * If the tag data would go past the end of the packet, abort.
294 	     */
295 	    ptn = (((const char *)(pt + 1)) + ntohs(pt->tag_len));
296 	    if(ptn > end)
297 		return NULL;
298 
299 	    if(pt->tag_type == idx)
300 		return pt;
301 
302 	    pt = (const struct pppoe_tag*)ptn;
303 	}
304 	return NULL;
305 }
306 
307 /**************************************************************************
308  * inlines to initialise or add tags to a session's tag list,
309  **************************************************************************/
310 /*
311  * Initialise the session's tag list
312  */
313 static void
314 init_tags(sessp sp)
315 {
316 AAA
317 	if(sp->neg == NULL) {
318 		kprintf("pppoe: asked to init NULL neg pointer\n");
319 		return;
320 	}
321 	sp->neg->numtags = 0;
322 }
323 
324 static void
325 insert_tag(sessp sp, const struct pppoe_tag *tp)
326 {
327 	int	i;
328 	negp neg;
329 
330 AAA
331 	if((neg = sp->neg) == NULL) {
332 		kprintf("pppoe: asked to use NULL neg pointer\n");
333 		return;
334 	}
335 	if ((i = neg->numtags++) < NUMTAGS) {
336 		neg->tags[i] = tp;
337 	} else {
338 		kprintf("pppoe: asked to add too many tags to packet\n");
339 		neg->numtags--;
340 	}
341 }
342 
343 /*
344  * Make up a packet, using the tags filled out for the session.
345  *
346  * Assume that the actual pppoe header and ethernet header
347  * are filled out externally to this routine.
348  * Also assume that neg->wh points to the correct
349  * location at the front of the buffer space.
350  */
351 static void
352 make_packet(sessp sp) {
353 	struct pppoe_full_hdr *wh = &sp->neg->pkt->pkt_header;
354 	const struct pppoe_tag **tag;
355 	char *dp;
356 	int count;
357 	int tlen;
358 	u_int16_t length = 0;
359 
360 AAA
361 	if ((sp->neg == NULL) || (sp->neg->m == NULL)) {
362 		kprintf("pppoe: make_packet called from wrong state\n");
363 	}
364 	dp = (char *)wh->ph.tag;
365 	for (count = 0, tag = sp->neg->tags;
366 	    ((count < sp->neg->numtags) && (count < NUMTAGS));
367 	    tag++, count++) {
368 		tlen = ntohs((*tag)->tag_len) + sizeof(**tag);
369 		if ((length + tlen) > (ETHER_MAX_LEN - 4 - sizeof(*wh))) {
370 			kprintf("pppoe: tags too long\n");
371 			sp->neg->numtags = count;
372 			break;	/* XXX chop off what's too long */
373 		}
374 		bcopy(*tag, (char *)dp, tlen);
375 		length += tlen;
376 		dp += tlen;
377 	}
378  	wh->ph.length = htons(length);
379 	sp->neg->m->m_len = length + sizeof(*wh);
380 	sp->neg->m->m_pkthdr.len = length + sizeof(*wh);
381 }
382 
383 /**************************************************************************
384  * Routine to match a service offered					  *
385  **************************************************************************/
386 /*
387  * Find a hook that has a service string that matches that
388  * we are seeking. for now use a simple string.
389  * In the future we may need something like regexp().
390  * for testing allow a null string to match 1st found and a null service
391  * to match all requests. Also make '*' do the same.
392  */
393 
394 #define NG_MATCH_EXACT	1
395 #define NG_MATCH_ANY	2
396 
397 static hook_p
398 pppoe_match_svc(node_p node, const char *svc_name, int svc_len, int match)
399 {
400 	sessp	sp	= NULL;
401 	negp	neg	= NULL;
402 	priv_p	privp	= node->private;
403 	hook_p	allhook	= NULL;
404 	hook_p	hook;
405 
406 AAA
407 	LIST_FOREACH(hook, &node->hooks, hooks) {
408 
409 		/* skip any hook that is debug or ethernet */
410 		if ((hook->private == &privp->debug_hook)
411 		||  (hook->private == &privp->ethernet_hook))
412 			continue;
413 		sp = hook->private;
414 
415 		/* Skip any sessions which are not in LISTEN mode. */
416 		if ( sp->state != PPPOE_LISTENING)
417 			continue;
418 
419 		neg = sp->neg;
420 
421 		/* Special case for a blank or "*" service name (wildcard) */
422 		if (match == NG_MATCH_ANY && neg->service_len == 1 &&
423 		    neg->service.data[0] == '*') {
424 			allhook = hook;
425 			continue;
426 		}
427 
428 		/* If the lengths don't match, that aint it. */
429 		if (neg->service_len != svc_len)
430 			continue;
431 
432 		/* An exact match? */
433 		if (svc_len == 0)
434 			break;
435 
436 		if (strncmp(svc_name, neg->service.data, svc_len) == 0)
437 			break;
438 	}
439 	return (hook ? hook : allhook);
440 }
441 /**************************************************************************
442  * Routine to find a particular session that matches an incoming packet	  *
443  **************************************************************************/
444 static hook_p
445 pppoe_findsession(node_p node, const struct pppoe_full_hdr *wh)
446 {
447 	sessp	sp = NULL;
448 	hook_p hook = NULL;
449 	priv_p	privp = node->private;
450 	u_int16_t	session = ntohs(wh->ph.sid);
451 
452 	/*
453 	 * find matching peer/session combination.
454 	 */
455 AAA
456 	LIST_FOREACH(hook, &node->hooks, hooks) {
457 		/* don't check special hooks */
458 		if ((hook->private == &privp->debug_hook)
459 		||  (hook->private == &privp->ethernet_hook)) {
460 			continue;
461 		}
462 		sp = hook->private;
463 		if ( ( (sp->state == PPPOE_CONNECTED)
464 		    || (sp->state == PPPOE_NEWCONNECTED) )
465 		&& (sp->Session_ID == session)
466 		&& (bcmp(sp->pkt_hdr.eh.ether_dhost,
467 		    wh->eh.ether_shost,
468 		    ETHER_ADDR_LEN)) == 0) {
469 			break;
470 		}
471 	}
472 	return (hook);
473 }
474 
475 static hook_p
476 pppoe_finduniq(node_p node, const struct pppoe_tag *tag)
477 {
478 	hook_p hook = NULL;
479 	priv_p	privp = node->private;
480 	union uniq		uniq;
481 
482 AAA
483 	bcopy(tag->tag_data, uniq.bytes, sizeof(void *));
484 	/* cycle through all known hooks */
485 	LIST_FOREACH(hook, &node->hooks, hooks) {
486 		/* don't check special hooks */
487 		if ((hook->private == &privp->debug_hook)
488 		||  (hook->private == &privp->ethernet_hook))
489 			continue;
490 		if (uniq.pointer == hook->private)
491 			break;
492 	}
493 	return (hook);
494 }
495 
496 /**************************************************************************
497  * start of Netgraph entrypoints					  *
498  **************************************************************************/
499 
500 /*
501  * Allocate the private data structure and the generic node
502  * and link them together.
503  *
504  * ng_make_node_common() returns with a generic node struct
505  * with a single reference for us.. we transfer it to the
506  * private structure.. when we free the private struct we must
507  * unref the node so it gets freed too.
508  */
509 static int
510 ng_pppoe_constructor(node_p *nodep)
511 {
512 	priv_p privdata;
513 	int error;
514 
515 AAA
516 	/* Initialize private descriptor */
517 	MALLOC(privdata, priv_p, sizeof(*privdata), M_NETGRAPH, M_NOWAIT);
518 	if (privdata == NULL)
519 		return (ENOMEM);
520 	bzero(privdata, sizeof(*privdata));
521 
522 	/* Call the 'generic' (ie, superclass) node constructor */
523 	if ((error = ng_make_node_common(&typestruct, nodep))) {
524 		FREE(privdata, M_NETGRAPH);
525 		return (error);
526 	}
527 
528 	/* Link structs together; this counts as our one reference to *nodep */
529 	(*nodep)->private = privdata;
530 	privdata->node = *nodep;
531 	return (0);
532 }
533 
534 /*
535  * Give our ok for a hook to be added...
536  * point the hook's private info to the hook structure.
537  *
538  * The following hook names are special:
539  *  Ethernet:  the hook that should be connected to a NIC.
540  *  debug:	copies of data sent out here  (when I write the code).
541  * All other hook names need only be unique. (the framework checks this).
542  */
543 static int
544 ng_pppoe_newhook(node_p node, hook_p hook, const char *name)
545 {
546 	const priv_p privp = node->private;
547 	sessp sp;
548 
549 AAA
550 	if (strcmp(name, NG_PPPOE_HOOK_ETHERNET) == 0) {
551 		privp->ethernet_hook = hook;
552 		hook->private = &privp->ethernet_hook;
553 	} else if (strcmp(name, NG_PPPOE_HOOK_DEBUG) == 0) {
554 		privp->debug_hook = hook;
555 		hook->private = &privp->debug_hook;
556 	} else {
557 		/*
558 		 * Any other unique name is OK.
559 		 * The infrastructure has already checked that it's unique,
560 		 * so just allocate it and hook it in.
561 		 */
562 		MALLOC(sp, sessp, sizeof(*sp), M_NETGRAPH, M_NOWAIT);
563 		if (sp == NULL) {
564 				return (ENOMEM);
565 		}
566 		bzero(sp, sizeof(*sp));
567 
568 		hook->private = sp;
569 		sp->hook = hook;
570 	}
571 	return(0);
572 }
573 
574 /*
575  * Get a netgraph control message.
576  * Check it is one we understand. If needed, send a response.
577  * We sometimes save the address for an async action later.
578  * Always free the message.
579  */
580 static int
581 ng_pppoe_rcvmsg(node_p node,
582 	   struct ng_mesg *msg, const char *retaddr, struct ng_mesg **rptr)
583 {
584 	priv_p privp = node->private;
585 	struct ngpppoe_init_data *ourmsg = NULL;
586 	struct ng_mesg *resp = NULL;
587 	int error = 0;
588 	hook_p hook = NULL;
589 	sessp sp = NULL;
590 	negp neg = NULL;
591 
592 AAA
593 	/* Deal with message according to cookie and command */
594 	switch (msg->header.typecookie) {
595 	case NGM_PPPOE_COOKIE:
596 		switch (msg->header.cmd) {
597 		case NGM_PPPOE_CONNECT:
598 		case NGM_PPPOE_LISTEN:
599 		case NGM_PPPOE_OFFER:
600 		case NGM_PPPOE_SERVICE:
601 			ourmsg = (struct ngpppoe_init_data *)msg->data;
602 			if (( sizeof(*ourmsg) > msg->header.arglen)
603 			|| ((sizeof(*ourmsg) + ourmsg->data_len)
604 			    > msg->header.arglen)) {
605 				kprintf("pppoe_rcvmsg: bad arg size");
606 				LEAVE(EMSGSIZE);
607 			}
608 			if (ourmsg->data_len > PPPOE_SERVICE_NAME_SIZE) {
609 				kprintf("pppoe: init data too long (%d)\n",
610 							ourmsg->data_len);
611 				LEAVE(EMSGSIZE);
612 			}
613 			/* make sure strcmp will terminate safely */
614 			ourmsg->hook[sizeof(ourmsg->hook) - 1] = '\0';
615 
616 			/* cycle through all known hooks */
617 			LIST_FOREACH(hook, &node->hooks, hooks) {
618 				if (hook->name
619 				&& strcmp(hook->name, ourmsg->hook) == 0)
620 					break;
621 			}
622 			if (hook == NULL) {
623 				LEAVE(ENOENT);
624 			}
625 			if ((hook->private == &privp->debug_hook)
626 			||  (hook->private == &privp->ethernet_hook)) {
627 				LEAVE(EINVAL);
628 			}
629 			sp = hook->private;
630 
631 			if (msg->header.cmd == NGM_PPPOE_LISTEN) {
632 				/*
633 				 * Ensure we aren't already listening for this
634 				 * service.
635 				 */
636 				if (pppoe_match_svc(node, ourmsg->data,
637 				    ourmsg->data_len, NG_MATCH_EXACT) != NULL) {
638 					LEAVE(EEXIST);
639 				}
640 			}
641 
642 			/*
643 			 * PPPOE_SERVICE advertisments are set up
644 			 * on sessions that are in PRIMED state.
645 			 */
646 			if (msg->header.cmd == NGM_PPPOE_SERVICE) {
647 				break;
648 			}
649 			if (sp->state |= PPPOE_SNONE) {
650 				kprintf("pppoe: Session already active\n");
651 				LEAVE(EISCONN);
652 			}
653 
654 			/*
655 			 * set up prototype header
656 			 */
657 			MALLOC(neg, negp, sizeof(*neg), M_NETGRAPH, M_NOWAIT);
658 
659 			if (neg == NULL) {
660 				kprintf("pppoe: Session out of memory\n");
661 				LEAVE(ENOMEM);
662 			}
663 			bzero(neg, sizeof(*neg));
664 			MGETHDR(neg->m, MB_DONTWAIT, MT_DATA);
665 			if(neg->m == NULL) {
666 				kprintf("pppoe: Session out of mbufs\n");
667 				FREE(neg, M_NETGRAPH);
668 				LEAVE(ENOBUFS);
669 			}
670 			neg->m->m_pkthdr.rcvif = NULL;
671 			MCLGET(neg->m, MB_DONTWAIT);
672 			if ((neg->m->m_flags & M_EXT) == 0) {
673 				kprintf("pppoe: Session out of mcls\n");
674 				m_freem(neg->m);
675 				FREE(neg, M_NETGRAPH);
676 				LEAVE(ENOBUFS);
677 			}
678 			sp->neg = neg;
679 			callout_init(&neg->timeout_ch);
680 			neg->m->m_len = sizeof(struct pppoe_full_hdr);
681 			neg->pkt = mtod(neg->m, union packet*);
682 			neg->pkt->pkt_header.eh = eh_prototype;
683 			neg->pkt->pkt_header.ph.ver = 0x1;
684 			neg->pkt->pkt_header.ph.type = 0x1;
685 			neg->pkt->pkt_header.ph.sid = 0x0000;
686 			neg->timeout = 0;
687 
688 			strlcpy(sp->creator, retaddr, NG_NODESIZ);
689 		}
690 		switch (msg->header.cmd) {
691 		case NGM_PPPOE_GET_STATUS:
692 		    {
693 			struct ngpppoestat *stats;
694 
695 			NG_MKRESPONSE(resp, msg, sizeof(*stats), M_NOWAIT);
696 			if (!resp) {
697 				LEAVE(ENOMEM);
698 			}
699 			stats = (struct ngpppoestat *) resp->data;
700 			stats->packets_in = privp->packets_in;
701 			stats->packets_out = privp->packets_out;
702 			break;
703 		    }
704 		case NGM_PPPOE_CONNECT:
705 			/*
706 			 * Check the hook exists and is Uninitialised.
707 			 * Send a PADI request, and start the timeout logic.
708 			 * Store the originator of this message so we can send
709 			 * a success of fail message to them later.
710 			 * Move the session to SINIT
711 			 * Set up the session to the correct state and
712 			 * start it.
713 			 */
714 			neg->service.hdr.tag_type = PTT_SRV_NAME;
715 			neg->service.hdr.tag_len =
716 					htons((u_int16_t)ourmsg->data_len);
717 			if (ourmsg->data_len) {
718 				bcopy(ourmsg->data,
719 					neg->service.data, ourmsg->data_len);
720 			}
721 			neg->service_len = ourmsg->data_len;
722 			pppoe_start(sp);
723 			break;
724 		case NGM_PPPOE_LISTEN:
725 			/*
726 			 * Check the hook exists and is Uninitialised.
727 			 * Install the service matching string.
728 			 * Store the originator of this message so we can send
729 			 * a success of fail message to them later.
730 			 * Move the hook to 'LISTENING'
731 			 */
732 			neg->service.hdr.tag_type = PTT_SRV_NAME;
733 			neg->service.hdr.tag_len =
734 					htons((u_int16_t)ourmsg->data_len);
735 
736 			if (ourmsg->data_len) {
737 				bcopy(ourmsg->data,
738 					neg->service.data, ourmsg->data_len);
739 			}
740 			neg->service_len = ourmsg->data_len;
741 			neg->pkt->pkt_header.ph.code = PADT_CODE;
742 			/*
743 			 * wait for PADI packet coming from ethernet
744 			 */
745 			sp->state = PPPOE_LISTENING;
746 			break;
747 		case NGM_PPPOE_OFFER:
748 			/*
749 			 * Check the hook exists and is Uninitialised.
750 			 * Store the originator of this message so we can send
751 			 * a success of fail message to them later.
752 			 * Store the AC-Name given and go to PRIMED.
753 			 */
754 			neg->ac_name.hdr.tag_type = PTT_AC_NAME;
755 			neg->ac_name.hdr.tag_len =
756 					htons((u_int16_t)ourmsg->data_len);
757 			if (ourmsg->data_len) {
758 				bcopy(ourmsg->data,
759 					neg->ac_name.data, ourmsg->data_len);
760 			}
761 			neg->ac_name_len = ourmsg->data_len;
762 			neg->pkt->pkt_header.ph.code = PADO_CODE;
763 			/*
764 			 * Wait for PADI packet coming from hook
765 			 */
766 			sp->state = PPPOE_PRIMED;
767 			break;
768 		case NGM_PPPOE_SERVICE:
769 			/*
770 			 * Check the session is primed.
771 			 * for now just allow ONE service to be advertised.
772 			 * If you do it twice you just overwrite.
773 			 */
774 			if (sp->state != PPPOE_PRIMED) {
775 				kprintf("pppoe: Session not primed\n");
776 				LEAVE(EISCONN);
777 			}
778 			neg = sp->neg;
779 			neg->service.hdr.tag_type = PTT_SRV_NAME;
780 			neg->service.hdr.tag_len =
781 			    htons((u_int16_t)ourmsg->data_len);
782 
783 			if (ourmsg->data_len)
784 				bcopy(ourmsg->data, neg->service.data,
785 				    ourmsg->data_len);
786 			neg->service_len = ourmsg->data_len;
787 			break;
788 		default:
789 			LEAVE(EINVAL);
790 		}
791 		break;
792 	default:
793 		LEAVE(EINVAL);
794 	}
795 
796 	/* Take care of synchronous response, if any */
797 	if (rptr)
798 		*rptr = resp;
799 	else if (resp)
800 		FREE(resp, M_NETGRAPH);
801 
802 	/* Free the message and return */
803 quit:
804 	FREE(msg, M_NETGRAPH);
805 	return(error);
806 }
807 
808 /*
809  * Start a client into the first state. A separate function because
810  * it can be needed if the negotiation times out.
811  */
812 static void
813 pppoe_start(sessp sp)
814 {
815 	struct {
816 		struct pppoe_tag hdr;
817 		union	uniq	data;
818 	} __attribute ((packed)) uniqtag;
819 
820 	/*
821 	 * kick the state machine into starting up
822 	 */
823 AAA
824 	sp->state = PPPOE_SINIT;
825 	/* reset the packet header to broadcast */
826 	sp->neg->pkt->pkt_header.eh = eh_prototype;
827 	sp->neg->pkt->pkt_header.ph.code = PADI_CODE;
828 	uniqtag.hdr.tag_type = PTT_HOST_UNIQ;
829 	uniqtag.hdr.tag_len = htons((u_int16_t)sizeof(uniqtag.data));
830 	uniqtag.data.pointer = sp;
831 	init_tags(sp);
832 	insert_tag(sp, &uniqtag.hdr);
833 	insert_tag(sp, &sp->neg->service.hdr);
834 	make_packet(sp);
835 	sendpacket(sp);
836 }
837 
838 static int
839 send_acname(sessp sp, const struct pppoe_tag *tag)
840 {
841 	int error, tlen;
842 	struct ng_mesg *msg;
843 	struct ngpppoe_sts *sts;
844 
845 	NG_MKMESSAGE(msg, NGM_PPPOE_COOKIE, NGM_PPPOE_ACNAME,
846 	    sizeof(struct ngpppoe_sts), M_NOWAIT);
847 	if (msg == NULL)
848 		return (ENOMEM);
849 
850 	sts = (struct ngpppoe_sts *)msg->data;
851 	tlen = min(NG_HOOKSIZ - 1, ntohs(tag->tag_len));
852 	strncpy(sts->hook, tag->tag_data, tlen);
853 	sts->hook[tlen] = '\0';
854 	error = ng_send_msg(sp->hook->node, msg, sp->creator, NULL);
855 
856 	return (error);
857 }
858 
859 static int
860 send_sessionid(sessp sp)
861 {
862 	int error;
863 	struct ng_mesg *msg;
864 
865 	NG_MKMESSAGE(msg, NGM_PPPOE_COOKIE, NGM_PPPOE_SESSIONID,
866 	    sizeof(u_int16_t), M_NOWAIT);
867 	if (msg == NULL)
868 		return (ENOMEM);
869 
870 	*(u_int16_t *)msg->data = sp->Session_ID;
871 	error = ng_send_msg(sp->hook->node, msg, sp->creator, NULL);
872 
873 	return (error);
874 }
875 
876 /*
877  * Receive data, and do something with it.
878  * The caller will never free m or meta, so
879  * if we use up this data or abort we must free BOTH of these.
880  */
881 static int
882 ng_pppoe_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
883 {
884 	node_p			node = hook->node;
885 	const priv_p		privp = node->private;
886 	sessp			sp = hook->private;
887 	const struct pppoe_full_hdr *wh;
888 	const struct pppoe_hdr	*ph;
889 	int			error = 0;
890 	u_int16_t		session;
891 	u_int16_t		length;
892 	u_int8_t		code;
893 	const struct pppoe_tag	*utag = NULL, *tag = NULL;
894 	hook_p 			sendhook;
895 	struct {
896 		struct pppoe_tag hdr;
897 		union	uniq	data;
898 	} __attribute ((packed)) uniqtag;
899 	negp			neg = NULL;
900 
901 AAA
902 	if (hook->private == &privp->debug_hook) {
903 		/*
904 		 * Data from the debug hook gets sent without modification
905 		 * straight to the ethernet.
906 		 */
907 		NG_SEND_DATA( error, privp->ethernet_hook, m, meta);
908 	 	privp->packets_out++;
909 	} else if (hook->private == &privp->ethernet_hook) {
910 		/*
911 		 * Incoming data.
912 		 * Dig out various fields from the packet.
913 		 * use them to decide where to send it.
914 		 */
915 
916  		privp->packets_in++;
917 		if( m->m_len < sizeof(*wh)) {
918 			m = m_pullup(m, sizeof(*wh)); /* Checks length */
919 			if (m == NULL) {
920 				kprintf("couldn't m_pullup\n");
921 				LEAVE(ENOBUFS);
922 			}
923 		}
924 		wh = mtod(m, struct pppoe_full_hdr *);
925 		ph = &wh->ph;
926 		session = ntohs(wh->ph.sid);
927 		length = ntohs(wh->ph.length);
928 		code = wh->ph.code;
929 		switch(wh->eh.ether_type) {
930 		case	ETHERTYPE_PPPOE_STUPID_DISC:
931 			if (pppoe_mode == PPPOE_STANDARD) {
932 				pppoe_mode = PPPOE_NONSTANDARD;
933 				eh_prototype.ether_type =
934 				    ETHERTYPE_PPPOE_STUPID_DISC;
935 				log(LOG_NOTICE,
936 				    "Switched to nonstandard PPPoE mode due to "
937 				    "packet from %*D\n",
938 				    ETHER_ADDR_LEN,
939 				    wh->eh.ether_shost, ":");
940 			} else if (pppoe_mode == PPPOE_KEEPSTANDARD)
941 				log(LOG_NOTICE,
942 				    "Ignored nonstandard PPPoE packet "
943 				    "from %*D\n",
944 				    ETHER_ADDR_LEN,
945 				    wh->eh.ether_shost, ":");
946 			/* fall through */
947 		case	ETHERTYPE_PPPOE_DISC:
948 			/*
949 			 * We need to try to make sure that the tag area
950 			 * is contiguous, or we could wander off the end
951 			 * of a buffer and make a mess.
952 			 * (Linux wouldn't have this problem).
953 			 */
954 /*XXX fix this mess */
955 
956 			if (m->m_pkthdr.len <= MHLEN) {
957 				if( m->m_len < m->m_pkthdr.len) {
958 					m = m_pullup(m, m->m_pkthdr.len);
959 					if (m == NULL) {
960 						kprintf("couldn't m_pullup\n");
961 						LEAVE(ENOBUFS);
962 					}
963 				}
964 			}
965 			if (m->m_len != m->m_pkthdr.len) {
966 				/*
967 				 * It's not all in one piece.
968 				 * We need to do extra work.
969 				 */
970 				kprintf("packet fragmented\n");
971 				LEAVE(EMSGSIZE);
972 			}
973 
974 			switch(code) {
975 			case	PADI_CODE:
976 				/*
977 				 * We are a server:
978 				 * Look for a hook with the required service
979 				 * and send the ENTIRE packet up there.
980 				 * It should come back to a new hook in
981 				 * PRIMED state. Look there for further
982 				 * processing.
983 				 */
984 				tag = get_tag(ph, PTT_SRV_NAME);
985 				if (tag == NULL) {
986 					kprintf("no service tag\n");
987 					LEAVE(ENETUNREACH);
988 				}
989 				sendhook = pppoe_match_svc(hook->node,
990 			    		tag->tag_data, ntohs(tag->tag_len),
991 					NG_MATCH_ANY);
992 				if (sendhook) {
993 					NG_SEND_DATA(error, sendhook, m, meta);
994 				} else {
995 					LEAVE(ENETUNREACH);
996 				}
997 				break;
998 			case	PADO_CODE:
999 				/*
1000 				 * We are a client:
1001 				 * Use the host_uniq tag to find the
1002 				 * hook this is in response to.
1003 				 * Received #2, now send #3
1004 				 * For now simply accept the first we receive.
1005 				 */
1006 				utag = get_tag(ph, PTT_HOST_UNIQ);
1007 				if ((utag == NULL)
1008 				|| (ntohs(utag->tag_len) != sizeof(sp))) {
1009 					kprintf("no host unique field\n");
1010 					LEAVE(ENETUNREACH);
1011 				}
1012 
1013 				sendhook = pppoe_finduniq(node, utag);
1014 				if (sendhook == NULL) {
1015 					kprintf("no matching session\n");
1016 					LEAVE(ENETUNREACH);
1017 				}
1018 
1019 				/*
1020 				 * Check the session is in the right state.
1021 				 * It needs to be in PPPOE_SINIT.
1022 				 */
1023 				sp = sendhook->private;
1024 				if (sp->state != PPPOE_SINIT) {
1025 					kprintf("session in wrong state\n");
1026 					LEAVE(ENETUNREACH);
1027 				}
1028 				neg = sp->neg;
1029 				callout_stop(&neg->timeout_ch);
1030 
1031 				/*
1032 				 * This is the first time we hear
1033 				 * from the server, so note it's
1034 				 * unicast address, replacing the
1035 				 * broadcast address .
1036 				 */
1037 				bcopy(wh->eh.ether_shost,
1038 					neg->pkt->pkt_header.eh.ether_dhost,
1039 					ETHER_ADDR_LEN);
1040 				neg->timeout = 0;
1041 				neg->pkt->pkt_header.ph.code = PADR_CODE;
1042 				init_tags(sp);
1043 				insert_tag(sp, utag);      /* Host Unique */
1044 				if ((tag = get_tag(ph, PTT_AC_COOKIE)))
1045 					insert_tag(sp, tag); /* return cookie */
1046 				if ((tag = get_tag(ph, PTT_AC_NAME))) {
1047 					insert_tag(sp, tag); /* return it */
1048 					send_acname(sp, tag);
1049 				}
1050 				insert_tag(sp, &neg->service.hdr); /* Service */
1051 				scan_tags(sp, ph);
1052 				make_packet(sp);
1053 				sp->state = PPPOE_SREQ;
1054 				sendpacket(sp);
1055 				break;
1056 			case	PADR_CODE:
1057 
1058 				/*
1059 				 * We are a server:
1060 				 * Use the ac_cookie tag to find the
1061 				 * hook this is in response to.
1062 				 */
1063 				utag = get_tag(ph, PTT_AC_COOKIE);
1064 				if ((utag == NULL)
1065 				|| (ntohs(utag->tag_len) != sizeof(sp))) {
1066 					LEAVE(ENETUNREACH);
1067 				}
1068 
1069 				sendhook = pppoe_finduniq(node, utag);
1070 				if (sendhook == NULL) {
1071 					LEAVE(ENETUNREACH);
1072 				}
1073 
1074 				/*
1075 				 * Check the session is in the right state.
1076 				 * It needs to be in PPPOE_SOFFER
1077 				 * or PPPOE_NEWCONNECTED. If the latter,
1078 				 * then this is a retry by the client.
1079 				 * so be nice, and resend.
1080 				 */
1081 				sp = sendhook->private;
1082 				if (sp->state == PPPOE_NEWCONNECTED) {
1083 					/*
1084 					 * Whoa! drop back to resend that
1085 					 * PADS packet.
1086 					 * We should still have a copy of it.
1087 					 */
1088 					sp->state = PPPOE_SOFFER;
1089 				}
1090 				if (sp->state != PPPOE_SOFFER) {
1091 					LEAVE (ENETUNREACH);
1092 					break;
1093 				}
1094 				neg = sp->neg;
1095 				callout_stop(&neg->timeout_ch);
1096 				neg->pkt->pkt_header.ph.code = PADS_CODE;
1097 				if (sp->Session_ID == 0)
1098 					neg->pkt->pkt_header.ph.sid =
1099 					    htons(sp->Session_ID
1100 						= get_new_sid(node));
1101 				send_sessionid(sp);
1102 				neg->timeout = 0;
1103 				/*
1104 				 * start working out the tags to respond with.
1105 				 */
1106 				init_tags(sp);
1107 				insert_tag(sp, &neg->ac_name.hdr); /* AC_NAME */
1108 				if ((tag = get_tag(ph, PTT_SRV_NAME)))
1109 					insert_tag(sp, tag);/* return service */
1110 				if ((tag = get_tag(ph, PTT_HOST_UNIQ)))
1111 					insert_tag(sp, tag); /* return it */
1112 				insert_tag(sp, utag);	/* ac_cookie */
1113 				scan_tags(sp, ph);
1114 				make_packet(sp);
1115 				sp->state = PPPOE_NEWCONNECTED;
1116 				sendpacket(sp);
1117 				/*
1118 				 * Having sent the last Negotiation header,
1119 				 * Set up the stored packet header to
1120 				 * be correct for the actual session.
1121 				 * But keep the negotialtion stuff
1122 				 * around in case we need to resend this last
1123 				 * packet. We'll discard it when we move
1124 				 * from NEWCONNECTED to CONNECTED
1125 				 */
1126 				sp->pkt_hdr = neg->pkt->pkt_header;
1127 				if (pppoe_mode == PPPOE_NONSTANDARD)
1128 					sp->pkt_hdr.eh.ether_type
1129 						= ETHERTYPE_PPPOE_STUPID_SESS;
1130 				else
1131 					sp->pkt_hdr.eh.ether_type
1132 						= ETHERTYPE_PPPOE_SESS;
1133 				sp->pkt_hdr.ph.code = 0;
1134 				pppoe_send_event(sp, NGM_PPPOE_SUCCESS);
1135 				break;
1136 			case	PADS_CODE:
1137 				/*
1138 				 * We are a client:
1139 				 * Use the host_uniq tag to find the
1140 				 * hook this is in response to.
1141 				 * take the session ID and store it away.
1142 				 * Also make sure the pre-made header is
1143 				 * correct and set us into Session mode.
1144 				 */
1145 				utag = get_tag(ph, PTT_HOST_UNIQ);
1146 				if ((utag == NULL)
1147 				|| (ntohs(utag->tag_len) != sizeof(sp))) {
1148 					LEAVE (ENETUNREACH);
1149 					break;
1150 				}
1151 				sendhook = pppoe_finduniq(node, utag);
1152 				if (sendhook == NULL) {
1153 					LEAVE(ENETUNREACH);
1154 				}
1155 
1156 				/*
1157 				 * Check the session is in the right state.
1158 				 * It needs to be in PPPOE_SREQ.
1159 				 */
1160 				sp = sendhook->private;
1161 				if (sp->state != PPPOE_SREQ) {
1162 					LEAVE(ENETUNREACH);
1163 				}
1164 				neg = sp->neg;
1165 				callout_stop(&neg->timeout_ch);
1166 				neg->pkt->pkt_header.ph.sid = wh->ph.sid;
1167 				sp->Session_ID = ntohs(wh->ph.sid);
1168 				send_sessionid(sp);
1169 				neg->timeout = 0;
1170 				sp->state = PPPOE_CONNECTED;
1171 				/*
1172 				 * Now we have gone to Connected mode,
1173 				 * Free all resources needed for
1174 				 * negotiation.
1175 				 * Keep a copy of the header we will be using.
1176 				 */
1177 				sp->pkt_hdr = neg->pkt->pkt_header;
1178 				if (pppoe_mode == PPPOE_NONSTANDARD)
1179 					sp->pkt_hdr.eh.ether_type
1180 						= ETHERTYPE_PPPOE_STUPID_SESS;
1181 				else
1182 					sp->pkt_hdr.eh.ether_type
1183 						= ETHERTYPE_PPPOE_SESS;
1184 				sp->pkt_hdr.ph.code = 0;
1185 				m_freem(neg->m);
1186 				FREE(sp->neg, M_NETGRAPH);
1187 				sp->neg = NULL;
1188 				pppoe_send_event(sp, NGM_PPPOE_SUCCESS);
1189 				break;
1190 			case	PADT_CODE:
1191 				/*
1192 				 * Send a 'close' message to the controlling
1193 				 * process (the one that set us up);
1194 				 * And then tear everything down.
1195 				 *
1196 				 * Find matching peer/session combination.
1197 				 */
1198 				sendhook = pppoe_findsession(node, wh);
1199 				NG_FREE_DATA(m, meta); /* no longer needed */
1200 				if (sendhook == NULL) {
1201 					LEAVE(ENETUNREACH);
1202 				}
1203 				/* send message to creator */
1204 				/* close hook */
1205 				if (sendhook) {
1206 					ng_destroy_hook(sendhook);
1207 				}
1208 				break;
1209 			default:
1210 				LEAVE(EPFNOSUPPORT);
1211 			}
1212 			break;
1213 		case	ETHERTYPE_PPPOE_STUPID_SESS:
1214 		case	ETHERTYPE_PPPOE_SESS:
1215 			/*
1216 			 * find matching peer/session combination.
1217 			 */
1218 			sendhook = pppoe_findsession(node, wh);
1219 			if (sendhook == NULL) {
1220 				LEAVE (ENETUNREACH);
1221 				break;
1222 			}
1223 			sp = sendhook->private;
1224 			m_adj(m, sizeof(*wh));
1225 			if (m->m_pkthdr.len < length) {
1226 				/* Packet too short, dump it */
1227 				LEAVE(EMSGSIZE);
1228 			}
1229 
1230 			/* Also need to trim excess at the end */
1231 			if (m->m_pkthdr.len > length) {
1232 				m_adj(m, -((int)(m->m_pkthdr.len - length)));
1233 			}
1234 			if ( sp->state != PPPOE_CONNECTED) {
1235 				if (sp->state == PPPOE_NEWCONNECTED) {
1236 					sp->state = PPPOE_CONNECTED;
1237 					/*
1238 					 * Now we have gone to Connected mode,
1239 					 * Free all resources needed for
1240 					 * negotiation. Be paranoid about
1241 					 * whether there may be a timeout.
1242 					 */
1243 					m_freem(sp->neg->m);
1244 					callout_stop(&sp->neg->timeout_ch);
1245 					FREE(sp->neg, M_NETGRAPH);
1246 					sp->neg = NULL;
1247 				} else {
1248 					LEAVE (ENETUNREACH);
1249 					break;
1250 				}
1251 			}
1252 			NG_SEND_DATA( error, sendhook, m, meta);
1253 			break;
1254 		default:
1255 			LEAVE(EPFNOSUPPORT);
1256 		}
1257 	} else {
1258 		/*
1259 		 * 	Not ethernet or debug hook..
1260 		 *
1261 		 * The packet has come in on a normal hook.
1262 		 * We need to find out what kind of hook,
1263 		 * So we can decide how to handle it.
1264 		 * Check the hook's state.
1265 		 */
1266 		sp = hook->private;
1267 		switch (sp->state) {
1268 		case	PPPOE_NEWCONNECTED:
1269 		case	PPPOE_CONNECTED: {
1270 			static const u_char addrctrl[] = { 0xff, 0x03 };
1271 			struct pppoe_full_hdr *wh;
1272 
1273 			/*
1274 			 * Remove PPP address and control fields, if any.
1275 			 * For example, ng_ppp(4) always sends LCP packets
1276 			 * with address and control fields as required by
1277 			 * generic PPP. PPPoE is an exception to the rule.
1278 			 */
1279 			if (m->m_pkthdr.len >= 2) {
1280 				if (m->m_len < 2 && !(m = m_pullup(m, 2)))
1281 					LEAVE(ENOBUFS);
1282 				if (bcmp(mtod(m, u_char *), addrctrl, 2) == 0)
1283 					m_adj(m, 2);
1284 			}
1285 			/*
1286 			 * Bang in a pre-made header, and set the length up
1287 			 * to be correct. Then send it to the ethernet driver.
1288 			 * But first correct the length.
1289 			 */
1290 			sp->pkt_hdr.ph.length = htons((short)(m->m_pkthdr.len));
1291 			M_PREPEND(m, sizeof(*wh), MB_DONTWAIT);
1292 			if (m == NULL) {
1293 				LEAVE(ENOBUFS);
1294 			}
1295 			wh = mtod(m, struct pppoe_full_hdr *);
1296 			bcopy(&sp->pkt_hdr, wh, sizeof(*wh));
1297 			NG_SEND_DATA( error, privp->ethernet_hook, m, meta);
1298 			privp->packets_out++;
1299 			break;
1300 			}
1301 		case	PPPOE_PRIMED:
1302 			/*
1303 			 * A PADI packet is being returned by the application
1304 			 * that has set up this hook. This indicates that it
1305 			 * wants us to offer service.
1306 			 */
1307 			neg = sp->neg;
1308 			if (m->m_len < sizeof(*wh)) {
1309 				m = m_pullup(m, sizeof(*wh));
1310 				if (m == NULL) {
1311 					LEAVE(ENOBUFS);
1312 				}
1313 			}
1314 			wh = mtod(m, struct pppoe_full_hdr *);
1315 			ph = &wh->ph;
1316 			session = ntohs(wh->ph.sid);
1317 			length = ntohs(wh->ph.length);
1318 			code = wh->ph.code;
1319 			if ( code != PADI_CODE) {
1320 				LEAVE(EINVAL);
1321 			};
1322 			callout_stop(&neg->timeout_ch);
1323 
1324 			/*
1325 			 * This is the first time we hear
1326 			 * from the client, so note it's
1327 			 * unicast address, replacing the
1328 			 * broadcast address.
1329 			 */
1330 			bcopy(wh->eh.ether_shost,
1331 				neg->pkt->pkt_header.eh.ether_dhost,
1332 				ETHER_ADDR_LEN);
1333 			sp->state = PPPOE_SOFFER;
1334 			neg->timeout = 0;
1335 			neg->pkt->pkt_header.ph.code = PADO_CODE;
1336 
1337 			/*
1338 			 * start working out the tags to respond with.
1339 			 */
1340 			uniqtag.hdr.tag_type = PTT_AC_COOKIE;
1341 			uniqtag.hdr.tag_len = htons((u_int16_t)sizeof(sp));
1342 			uniqtag.data.pointer = sp;
1343 			init_tags(sp);
1344 			insert_tag(sp, &neg->ac_name.hdr); /* AC_NAME */
1345 			if ((tag = get_tag(ph, PTT_SRV_NAME)))
1346 				insert_tag(sp, tag);	  /* return service */
1347 			/*
1348 			 * If we have a NULL service request
1349 			 * and have an extra service defined in this hook,
1350 			 * then also add a tag for the extra service.
1351 			 * XXX this is a hack. eventually we should be able
1352 			 * to support advertising many services, not just one
1353 			 */
1354 			if (((tag == NULL) || (tag->tag_len == 0))
1355 			&& (neg->service.hdr.tag_len != 0)) {
1356 				insert_tag(sp, &neg->service.hdr); /* SERVICE */
1357 			}
1358 			if ((tag = get_tag(ph, PTT_HOST_UNIQ)))
1359 				insert_tag(sp, tag); /* returned hostunique */
1360 			insert_tag(sp, &uniqtag.hdr);
1361 			scan_tags(sp, ph);
1362 			make_packet(sp);
1363 			sendpacket(sp);
1364 			break;
1365 
1366 		/*
1367 		 * Packets coming from the hook make no sense
1368 		 * to sessions in these states. Throw them away.
1369 		 */
1370 		case	PPPOE_SINIT:
1371 		case	PPPOE_SREQ:
1372 		case	PPPOE_SOFFER:
1373 		case	PPPOE_SNONE:
1374 		case	PPPOE_LISTENING:
1375 		case	PPPOE_DEAD:
1376 		default:
1377 			LEAVE(ENETUNREACH);
1378 		}
1379 	}
1380 quit:
1381 	NG_FREE_DATA(m, meta);
1382 	return error;
1383 }
1384 
1385 /*
1386  * Do local shutdown processing..
1387  * If we are a persistant device, we might refuse to go away, and
1388  * we'd only remove our links and reset ourself.
1389  */
1390 static int
1391 ng_pppoe_rmnode(node_p node)
1392 {
1393 	const priv_p privdata = node->private;
1394 
1395 AAA
1396 	node->flags |= NG_INVALID;
1397 	ng_cutlinks(node);
1398 	ng_unname(node);
1399 	node->private = NULL;
1400 	ng_unref(privdata->node);
1401 	FREE(privdata, M_NETGRAPH);
1402 	return (0);
1403 }
1404 
1405 /*
1406  * This is called once we've already connected a new hook to the other node.
1407  * It gives us a chance to balk at the last minute.
1408  */
1409 static int
1410 ng_pppoe_connect(hook_p hook)
1411 {
1412 	/* be really amiable and just say "YUP that's OK by me! " */
1413 	return (0);
1414 }
1415 
1416 /*
1417  * Hook disconnection
1418  *
1419  * Clean up all dangling links and information about the session/hook.
1420  * For this type, removal of the last link destroys the node
1421  */
1422 static int
1423 ng_pppoe_disconnect(hook_p hook)
1424 {
1425 	node_p node = hook->node;
1426 	priv_p privp = node->private;
1427 	sessp	sp;
1428 	int 	hooks;
1429 
1430 AAA
1431 	hooks = node->numhooks; /* this one already not counted */
1432 	if (hook->private == &privp->debug_hook) {
1433 		privp->debug_hook = NULL;
1434 	} else if (hook->private == &privp->ethernet_hook) {
1435 		privp->ethernet_hook = NULL;
1436 		ng_rmnode(node);
1437 	} else {
1438 		sp = hook->private;
1439 		if (sp->state != PPPOE_SNONE ) {
1440 			pppoe_send_event(sp, NGM_PPPOE_CLOSE);
1441 		}
1442 		/*
1443 		 * According to the spec, if we are connected,
1444 		 * we should send a DISC packet if we are shutting down
1445 		 * a session.
1446 		 */
1447 		if ((privp->ethernet_hook)
1448 		&& ((sp->state == PPPOE_CONNECTED)
1449 		 || (sp->state == PPPOE_NEWCONNECTED))) {
1450 			struct mbuf *m;
1451 			struct pppoe_full_hdr *wh;
1452 			struct pppoe_tag *tag;
1453 			int	msglen = strlen(SIGNOFF);
1454 			void *dummy = NULL;
1455 			int error = 0;
1456 
1457 			/* revert the stored header to DISC/PADT mode */
1458 		 	wh = &sp->pkt_hdr;
1459 			wh->ph.code = PADT_CODE;
1460 			if (pppoe_mode == PPPOE_NONSTANDARD)
1461 				wh->eh.ether_type = ETHERTYPE_PPPOE_STUPID_DISC;
1462 			else
1463 				wh->eh.ether_type = ETHERTYPE_PPPOE_DISC;
1464 
1465 			/* generate a packet of that type */
1466 			MGETHDR(m, MB_DONTWAIT, MT_DATA);
1467 			if(m == NULL)
1468 				kprintf("pppoe: Session out of mbufs\n");
1469 			else {
1470 				m->m_pkthdr.rcvif = NULL;
1471 				m->m_pkthdr.len = m->m_len = sizeof(*wh);
1472 				bcopy((caddr_t)wh, mtod(m, caddr_t),
1473 				    sizeof(*wh));
1474 				/*
1475 				 * Add a General error message and adjust
1476 				 * sizes
1477 				 */
1478 				wh = mtod(m, struct pppoe_full_hdr *);
1479 				tag = wh->ph.tag;
1480 				tag->tag_type = PTT_GEN_ERR;
1481 				tag->tag_len = htons((u_int16_t)msglen);
1482 				strncpy(tag->tag_data, SIGNOFF, msglen);
1483 				m->m_pkthdr.len = (m->m_len += sizeof(*tag) +
1484 				    msglen);
1485 				wh->ph.length = htons(sizeof(*tag) + msglen);
1486 				NG_SEND_DATA(error, privp->ethernet_hook, m,
1487 				    dummy);
1488 			}
1489 		}
1490 		/*
1491 		 * As long as we have somewhere to store the timeout handle,
1492 		 * we may have a timeout pending.. get rid of it.
1493 		 */
1494 		if (sp->neg) {
1495 			callout_stop(&sp->neg->timeout_ch);
1496 			if (sp->neg->m)
1497 				m_freem(sp->neg->m);
1498 			FREE(sp->neg, M_NETGRAPH);
1499 		}
1500 		FREE(sp, M_NETGRAPH);
1501 		hook->private = NULL;
1502 		/* work out how many session hooks there are */
1503 		/* Node goes away on last session hook removal */
1504 		if (privp->ethernet_hook) hooks -= 1;
1505 		if (privp->debug_hook) hooks -= 1;
1506 	}
1507 	if (node->numhooks == 0)
1508 		ng_rmnode(node);
1509 	return (0);
1510 }
1511 
1512 /*
1513  * timeouts come here.
1514  */
1515 static void
1516 pppoe_ticker(void *arg)
1517 {
1518 	hook_p hook = arg;
1519 	sessp	sp = hook->private;
1520 	negp	neg = sp->neg;
1521 	int	error = 0;
1522 	struct mbuf *m0 = NULL;
1523 	priv_p privp = hook->node->private;
1524 	meta_p dummy = NULL;
1525 
1526 	crit_enter();
1527 AAA
1528 	switch(sp->state) {
1529 		/*
1530 		 * resend the last packet, using an exponential backoff.
1531 		 * After a period of time, stop growing the backoff,
1532 		 * and either leave it, or revert to the start.
1533 		 */
1534 	case	PPPOE_SINIT:
1535 	case	PPPOE_SREQ:
1536 		/* timeouts on these produce resends */
1537 		m0 = m_copypacket(sp->neg->m, MB_DONTWAIT);
1538 		NG_SEND_DATA( error, privp->ethernet_hook, m0, dummy);
1539 		callout_reset(&neg->timeout_ch, neg->timeout * hz,
1540 				pppoe_ticker, hook);
1541 		if ((neg->timeout <<= 1) > PPPOE_TIMEOUT_LIMIT) {
1542 			if (sp->state == PPPOE_SREQ) {
1543 				/* revert to SINIT mode */
1544 				pppoe_start(sp);
1545 			} else {
1546 				neg->timeout = PPPOE_TIMEOUT_LIMIT;
1547 			}
1548 		}
1549 		break;
1550 	case	PPPOE_PRIMED:
1551 	case	PPPOE_SOFFER:
1552 		/* a timeout on these says "give up" */
1553 		ng_destroy_hook(hook);
1554 		break;
1555 	default:
1556 		/* timeouts have no meaning in other states */
1557 		kprintf("pppoe: unexpected timeout\n");
1558 	}
1559 	crit_exit();
1560 }
1561 
1562 
1563 static void
1564 sendpacket(sessp sp)
1565 {
1566 	int	error = 0;
1567 	struct mbuf *m0 = NULL;
1568 	hook_p hook = sp->hook;
1569 	negp	neg = sp->neg;
1570 	priv_p	privp = hook->node->private;
1571 	meta_p dummy = NULL;
1572 
1573 AAA
1574 	switch(sp->state) {
1575 	case	PPPOE_LISTENING:
1576 	case	PPPOE_DEAD:
1577 	case	PPPOE_SNONE:
1578 	case	PPPOE_CONNECTED:
1579 		kprintf("pppoe: sendpacket: unexpected state\n");
1580 		break;
1581 
1582 	case	PPPOE_NEWCONNECTED:
1583 		/* send the PADS without a timeout - we're now connected */
1584 		m0 = m_copypacket(sp->neg->m, MB_DONTWAIT);
1585 		NG_SEND_DATA( error, privp->ethernet_hook, m0, dummy);
1586 		break;
1587 
1588 	case	PPPOE_PRIMED:
1589 		/* No packet to send, but set up the timeout */
1590 		callout_reset(&neg->timeout_ch, PPPOE_OFFER_TIMEOUT * hz,
1591 				pppoe_ticker, hook);
1592 		break;
1593 
1594 	case	PPPOE_SOFFER:
1595 		/*
1596 		 * send the offer but if they don't respond
1597 		 * in PPPOE_OFFER_TIMEOUT seconds, forget about it.
1598 		 */
1599 		m0 = m_copypacket(sp->neg->m, MB_DONTWAIT);
1600 		NG_SEND_DATA( error, privp->ethernet_hook, m0, dummy);
1601 		callout_reset(&neg->timeout_ch, PPPOE_OFFER_TIMEOUT * hz,
1602 				pppoe_ticker, hook);
1603 		break;
1604 
1605 	case	PPPOE_SINIT:
1606 	case	PPPOE_SREQ:
1607 		m0 = m_copypacket(sp->neg->m, MB_DONTWAIT);
1608 		NG_SEND_DATA( error, privp->ethernet_hook, m0, dummy);
1609 		callout_reset(&neg->timeout_ch, PPPOE_INITIAL_TIMEOUT * hz,
1610 				pppoe_ticker, hook);
1611 		neg->timeout = PPPOE_INITIAL_TIMEOUT * 2;
1612 		break;
1613 
1614 	default:
1615 		error = EINVAL;
1616 		kprintf("pppoe: timeout: bad state\n");
1617 	}
1618 	/* return (error); */
1619 }
1620 
1621 /*
1622  * Parse an incoming packet to see if any tags should be copied to the
1623  * output packet. Don't do any tags that have been handled in the main
1624  * state machine.
1625  */
1626 static const struct pppoe_tag*
1627 scan_tags(sessp	sp, const struct pppoe_hdr* ph)
1628 {
1629 	const char *const end = (const char *)next_tag(ph);
1630 	const char *ptn;
1631 	const struct pppoe_tag *pt = &ph->tag[0];
1632 	/*
1633 	 * Keep processing tags while a tag header will still fit.
1634 	 */
1635 AAA
1636 	while((const char*)(pt + 1) <= end) {
1637 		/*
1638 		 * If the tag data would go past the end of the packet, abort.
1639 		 */
1640 		ptn = (((const char *)(pt + 1)) + ntohs(pt->tag_len));
1641 		if(ptn > end)
1642 			return NULL;
1643 
1644 		switch (pt->tag_type) {
1645 		case	PTT_RELAY_SID:
1646 			insert_tag(sp, pt);
1647 			break;
1648 		case	PTT_EOL:
1649 			return NULL;
1650 		case	PTT_SRV_NAME:
1651 		case	PTT_AC_NAME:
1652 		case	PTT_HOST_UNIQ:
1653 		case	PTT_AC_COOKIE:
1654 		case	PTT_VENDOR:
1655 		case	PTT_SRV_ERR:
1656 		case	PTT_SYS_ERR:
1657 		case	PTT_GEN_ERR:
1658 			break;
1659 		}
1660 		pt = (const struct pppoe_tag*)ptn;
1661 	}
1662 	return NULL;
1663 }
1664 
1665 static	int
1666 pppoe_send_event(sessp sp, enum cmd cmdid)
1667 {
1668 	int error;
1669 	struct ng_mesg *msg;
1670 	struct ngpppoe_sts *sts;
1671 
1672 AAA
1673 	NG_MKMESSAGE(msg, NGM_PPPOE_COOKIE, cmdid,
1674 			sizeof(struct ngpppoe_sts), M_NOWAIT);
1675 	if (msg == NULL)
1676 		return (ENOMEM);
1677 	sts = (struct ngpppoe_sts *)msg->data;
1678 	strlcpy(sts->hook, sp->hook->name, NG_HOOKSIZ);
1679 	error = ng_send_msg(sp->hook->node, msg, sp->creator, NULL);
1680 	return (error);
1681 }
1682