xref: /linux/net/appletalk/ddp.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1 /*
2  *	DDP:	An implementation of the AppleTalk DDP protocol for
3  *		Ethernet 'ELAP'.
4  *
5  *		Alan Cox  <Alan.Cox@linux.org>
6  *
7  *		With more than a little assistance from
8  *
9  *		Wesley Craig <netatalk@umich.edu>
10  *
11  *	Fixes:
12  *		Neil Horman		:	Added missing device ioctls
13  *		Michael Callahan	:	Made routing work
14  *		Wesley Craig		:	Fix probing to listen to a
15  *						passed node id.
16  *		Alan Cox		:	Added send/recvmsg support
17  *		Alan Cox		:	Moved at. to protinfo in
18  *						socket.
19  *		Alan Cox		:	Added firewall hooks.
20  *		Alan Cox		:	Supports new ARPHRD_LOOPBACK
21  *		Christer Weinigel	: 	Routing and /proc fixes.
22  *		Bradford Johnson	:	LocalTalk.
23  *		Tom Dyas		:	Module support.
24  *		Alan Cox		:	Hooks for PPP (based on the
25  *						LocalTalk hook).
26  *		Alan Cox		:	Posix bits
27  *		Alan Cox/Mike Freeman	:	Possible fix to NBP problems
28  *		Bradford Johnson	:	IP-over-DDP (experimental)
29  *		Jay Schulist		:	Moved IP-over-DDP to its own
30  *						driver file. (ipddp.c & ipddp.h)
31  *		Jay Schulist		:	Made work as module with
32  *						AppleTalk drivers, cleaned it.
33  *		Rob Newberry		:	Added proxy AARP and AARP
34  *						procfs, moved probing to AARP
35  *						module.
36  *              Adrian Sun/
37  *              Michael Zuelsdorff      :       fix for net.0 packets. don't
38  *                                              allow illegal ether/tokentalk
39  *                                              port assignment. we lose a
40  *                                              valid localtalk port as a
41  *                                              result.
42  *		Arnaldo C. de Melo	:	Cleanup, in preparation for
43  *						shared skb support 8)
44  *		Arnaldo C. de Melo	:	Move proc stuff to atalk_proc.c,
45  *						use seq_file
46  *
47  *		This program is free software; you can redistribute it and/or
48  *		modify it under the terms of the GNU General Public License
49  *		as published by the Free Software Foundation; either version
50  *		2 of the License, or (at your option) any later version.
51  *
52  */
53 
54 #include <linux/config.h>
55 #include <linux/capability.h>
56 #include <linux/module.h>
57 #include <linux/if_arp.h>
58 #include <linux/termios.h>	/* For TIOCOUTQ/INQ */
59 #include <net/datalink.h>
60 #include <net/psnap.h>
61 #include <net/sock.h>
62 #include <net/tcp_states.h>
63 #include <net/route.h>
64 #include <linux/atalk.h>
65 
66 struct datalink_proto *ddp_dl, *aarp_dl;
67 static const struct proto_ops atalk_dgram_ops;
68 
69 /**************************************************************************\
70 *                                                                          *
71 * Handlers for the socket list.                                            *
72 *                                                                          *
73 \**************************************************************************/
74 
75 HLIST_HEAD(atalk_sockets);
76 DEFINE_RWLOCK(atalk_sockets_lock);
77 
78 static inline void __atalk_insert_socket(struct sock *sk)
79 {
80 	sk_add_node(sk, &atalk_sockets);
81 }
82 
83 static inline void atalk_remove_socket(struct sock *sk)
84 {
85 	write_lock_bh(&atalk_sockets_lock);
86 	sk_del_node_init(sk);
87 	write_unlock_bh(&atalk_sockets_lock);
88 }
89 
90 static struct sock *atalk_search_socket(struct sockaddr_at *to,
91 					struct atalk_iface *atif)
92 {
93 	struct sock *s;
94 	struct hlist_node *node;
95 
96 	read_lock_bh(&atalk_sockets_lock);
97 	sk_for_each(s, node, &atalk_sockets) {
98 		struct atalk_sock *at = at_sk(s);
99 
100 		if (to->sat_port != at->src_port)
101 			continue;
102 
103 	    	if (to->sat_addr.s_net == ATADDR_ANYNET &&
104 		    to->sat_addr.s_node == ATADDR_BCAST)
105 			goto found;
106 
107 	    	if (to->sat_addr.s_net == at->src_net &&
108 		    (to->sat_addr.s_node == at->src_node ||
109 		     to->sat_addr.s_node == ATADDR_BCAST ||
110 		     to->sat_addr.s_node == ATADDR_ANYNODE))
111 			goto found;
112 
113 	    	/* XXXX.0 -- we got a request for this router. make sure
114 		 * that the node is appropriately set. */
115 		if (to->sat_addr.s_node == ATADDR_ANYNODE &&
116 		    to->sat_addr.s_net != ATADDR_ANYNET &&
117 		    atif->address.s_node == at->src_node) {
118 			to->sat_addr.s_node = atif->address.s_node;
119 			goto found;
120 		}
121 	}
122 	s = NULL;
123 found:
124 	read_unlock_bh(&atalk_sockets_lock);
125 	return s;
126 }
127 
128 /**
129  * atalk_find_or_insert_socket - Try to find a socket matching ADDR
130  * @sk - socket to insert in the list if it is not there already
131  * @sat - address to search for
132  *
133  * Try to find a socket matching ADDR in the socket list, if found then return
134  * it. If not, insert SK into the socket list.
135  *
136  * This entire operation must execute atomically.
137  */
138 static struct sock *atalk_find_or_insert_socket(struct sock *sk,
139 						struct sockaddr_at *sat)
140 {
141 	struct sock *s;
142 	struct hlist_node *node;
143 	struct atalk_sock *at;
144 
145 	write_lock_bh(&atalk_sockets_lock);
146 	sk_for_each(s, node, &atalk_sockets) {
147 		at = at_sk(s);
148 
149 		if (at->src_net == sat->sat_addr.s_net &&
150 		    at->src_node == sat->sat_addr.s_node &&
151 		    at->src_port == sat->sat_port)
152 			goto found;
153 	}
154 	s = NULL;
155 	__atalk_insert_socket(sk); /* Wheee, it's free, assign and insert. */
156 found:
157 	write_unlock_bh(&atalk_sockets_lock);
158 	return s;
159 }
160 
161 static void atalk_destroy_timer(unsigned long data)
162 {
163 	struct sock *sk = (struct sock *)data;
164 
165 	if (atomic_read(&sk->sk_wmem_alloc) ||
166 	    atomic_read(&sk->sk_rmem_alloc)) {
167 		sk->sk_timer.expires = jiffies + SOCK_DESTROY_TIME;
168 		add_timer(&sk->sk_timer);
169 	} else
170 		sock_put(sk);
171 }
172 
173 static inline void atalk_destroy_socket(struct sock *sk)
174 {
175 	atalk_remove_socket(sk);
176 	skb_queue_purge(&sk->sk_receive_queue);
177 
178 	if (atomic_read(&sk->sk_wmem_alloc) ||
179 	    atomic_read(&sk->sk_rmem_alloc)) {
180 		init_timer(&sk->sk_timer);
181 		sk->sk_timer.expires	= jiffies + SOCK_DESTROY_TIME;
182 		sk->sk_timer.function	= atalk_destroy_timer;
183 		sk->sk_timer.data	= (unsigned long)sk;
184 		add_timer(&sk->sk_timer);
185 	} else
186 		sock_put(sk);
187 }
188 
189 /**************************************************************************\
190 *                                                                          *
191 * Routing tables for the AppleTalk socket layer.                           *
192 *                                                                          *
193 \**************************************************************************/
194 
195 /* Anti-deadlock ordering is atalk_routes_lock --> iface_lock -DaveM */
196 struct atalk_route *atalk_routes;
197 DEFINE_RWLOCK(atalk_routes_lock);
198 
199 struct atalk_iface *atalk_interfaces;
200 DEFINE_RWLOCK(atalk_interfaces_lock);
201 
202 /* For probing devices or in a routerless network */
203 struct atalk_route atrtr_default;
204 
205 /* AppleTalk interface control */
206 /*
207  * Drop a device. Doesn't drop any of its routes - that is the caller's
208  * problem. Called when we down the interface or delete the address.
209  */
210 static void atif_drop_device(struct net_device *dev)
211 {
212 	struct atalk_iface **iface = &atalk_interfaces;
213 	struct atalk_iface *tmp;
214 
215 	write_lock_bh(&atalk_interfaces_lock);
216 	while ((tmp = *iface) != NULL) {
217 		if (tmp->dev == dev) {
218 			*iface = tmp->next;
219 			dev_put(dev);
220 			kfree(tmp);
221 			dev->atalk_ptr = NULL;
222 		} else
223 			iface = &tmp->next;
224 	}
225 	write_unlock_bh(&atalk_interfaces_lock);
226 }
227 
228 static struct atalk_iface *atif_add_device(struct net_device *dev,
229 					   struct atalk_addr *sa)
230 {
231 	struct atalk_iface *iface = kmalloc(sizeof(*iface), GFP_KERNEL);
232 
233 	if (!iface)
234 		goto out;
235 
236 	memset(iface, 0, sizeof(*iface));
237 	dev_hold(dev);
238 	iface->dev = dev;
239 	dev->atalk_ptr = iface;
240 	iface->address = *sa;
241 	iface->status = 0;
242 
243 	write_lock_bh(&atalk_interfaces_lock);
244 	iface->next = atalk_interfaces;
245 	atalk_interfaces = iface;
246 	write_unlock_bh(&atalk_interfaces_lock);
247 out:
248 	return iface;
249 }
250 
251 /* Perform phase 2 AARP probing on our tentative address */
252 static int atif_probe_device(struct atalk_iface *atif)
253 {
254 	int netrange = ntohs(atif->nets.nr_lastnet) -
255 			ntohs(atif->nets.nr_firstnet) + 1;
256 	int probe_net = ntohs(atif->address.s_net);
257 	int probe_node = atif->address.s_node;
258 	int netct, nodect;
259 
260 	/* Offset the network we start probing with */
261 	if (probe_net == ATADDR_ANYNET) {
262 		probe_net = ntohs(atif->nets.nr_firstnet);
263 		if (netrange)
264 			probe_net += jiffies % netrange;
265 	}
266 	if (probe_node == ATADDR_ANYNODE)
267 		probe_node = jiffies & 0xFF;
268 
269 	/* Scan the networks */
270 	atif->status |= ATIF_PROBE;
271 	for (netct = 0; netct <= netrange; netct++) {
272 		/* Sweep the available nodes from a given start */
273 		atif->address.s_net = htons(probe_net);
274 		for (nodect = 0; nodect < 256; nodect++) {
275 			atif->address.s_node = (nodect + probe_node) & 0xFF;
276 			if (atif->address.s_node > 0 &&
277 			    atif->address.s_node < 254) {
278 				/* Probe a proposed address */
279 				aarp_probe_network(atif);
280 
281 				if (!(atif->status & ATIF_PROBE_FAIL)) {
282 					atif->status &= ~ATIF_PROBE;
283 					return 0;
284 				}
285 			}
286 			atif->status &= ~ATIF_PROBE_FAIL;
287 		}
288 		probe_net++;
289 		if (probe_net > ntohs(atif->nets.nr_lastnet))
290 			probe_net = ntohs(atif->nets.nr_firstnet);
291 	}
292 	atif->status &= ~ATIF_PROBE;
293 
294 	return -EADDRINUSE;	/* Network is full... */
295 }
296 
297 
298 /* Perform AARP probing for a proxy address */
299 static int atif_proxy_probe_device(struct atalk_iface *atif,
300 				   struct atalk_addr* proxy_addr)
301 {
302 	int netrange = ntohs(atif->nets.nr_lastnet) -
303 			ntohs(atif->nets.nr_firstnet) + 1;
304 	/* we probe the interface's network */
305 	int probe_net = ntohs(atif->address.s_net);
306 	int probe_node = ATADDR_ANYNODE;	    /* we'll take anything */
307 	int netct, nodect;
308 
309 	/* Offset the network we start probing with */
310 	if (probe_net == ATADDR_ANYNET) {
311 		probe_net = ntohs(atif->nets.nr_firstnet);
312 		if (netrange)
313 			probe_net += jiffies % netrange;
314 	}
315 
316 	if (probe_node == ATADDR_ANYNODE)
317 		probe_node = jiffies & 0xFF;
318 
319 	/* Scan the networks */
320 	for (netct = 0; netct <= netrange; netct++) {
321 		/* Sweep the available nodes from a given start */
322 		proxy_addr->s_net = htons(probe_net);
323 		for (nodect = 0; nodect < 256; nodect++) {
324 			proxy_addr->s_node = (nodect + probe_node) & 0xFF;
325 			if (proxy_addr->s_node > 0 &&
326 			    proxy_addr->s_node < 254) {
327 				/* Tell AARP to probe a proposed address */
328 				int ret = aarp_proxy_probe_network(atif,
329 								    proxy_addr);
330 
331 				if (ret != -EADDRINUSE)
332 					return ret;
333 			}
334 		}
335 		probe_net++;
336 		if (probe_net > ntohs(atif->nets.nr_lastnet))
337 			probe_net = ntohs(atif->nets.nr_firstnet);
338 	}
339 
340 	return -EADDRINUSE;	/* Network is full... */
341 }
342 
343 
344 struct atalk_addr *atalk_find_dev_addr(struct net_device *dev)
345 {
346 	struct atalk_iface *iface = dev->atalk_ptr;
347 	return iface ? &iface->address : NULL;
348 }
349 
350 static struct atalk_addr *atalk_find_primary(void)
351 {
352 	struct atalk_iface *fiface = NULL;
353 	struct atalk_addr *retval;
354 	struct atalk_iface *iface;
355 
356 	/*
357 	 * Return a point-to-point interface only if
358 	 * there is no non-ptp interface available.
359 	 */
360 	read_lock_bh(&atalk_interfaces_lock);
361 	for (iface = atalk_interfaces; iface; iface = iface->next) {
362 		if (!fiface && !(iface->dev->flags & IFF_LOOPBACK))
363 			fiface = iface;
364 		if (!(iface->dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
365 			retval = &iface->address;
366 			goto out;
367 		}
368 	}
369 
370 	if (fiface)
371 		retval = &fiface->address;
372 	else if (atalk_interfaces)
373 		retval = &atalk_interfaces->address;
374 	else
375 		retval = NULL;
376 out:
377 	read_unlock_bh(&atalk_interfaces_lock);
378 	return retval;
379 }
380 
381 /*
382  * Find a match for 'any network' - ie any of our interfaces with that
383  * node number will do just nicely.
384  */
385 static struct atalk_iface *atalk_find_anynet(int node, struct net_device *dev)
386 {
387 	struct atalk_iface *iface = dev->atalk_ptr;
388 
389 	if (!iface || iface->status & ATIF_PROBE)
390 		goto out_err;
391 
392 	if (node != ATADDR_BCAST &&
393 	    iface->address.s_node != node &&
394 	    node != ATADDR_ANYNODE)
395 		goto out_err;
396 out:
397 	return iface;
398 out_err:
399 	iface = NULL;
400 	goto out;
401 }
402 
403 /* Find a match for a specific network:node pair */
404 static struct atalk_iface *atalk_find_interface(__be16 net, int node)
405 {
406 	struct atalk_iface *iface;
407 
408 	read_lock_bh(&atalk_interfaces_lock);
409 	for (iface = atalk_interfaces; iface; iface = iface->next) {
410 		if ((node == ATADDR_BCAST ||
411 		     node == ATADDR_ANYNODE ||
412 		     iface->address.s_node == node) &&
413 		    iface->address.s_net == net &&
414 		    !(iface->status & ATIF_PROBE))
415 			break;
416 
417 		/* XXXX.0 -- net.0 returns the iface associated with net */
418 		if (node == ATADDR_ANYNODE && net != ATADDR_ANYNET &&
419 		    ntohs(iface->nets.nr_firstnet) <= ntohs(net) &&
420 		    ntohs(net) <= ntohs(iface->nets.nr_lastnet))
421 		        break;
422 	}
423 	read_unlock_bh(&atalk_interfaces_lock);
424 	return iface;
425 }
426 
427 
428 /*
429  * Find a route for an AppleTalk packet. This ought to get cached in
430  * the socket (later on...). We know about host routes and the fact
431  * that a route must be direct to broadcast.
432  */
433 static struct atalk_route *atrtr_find(struct atalk_addr *target)
434 {
435 	/*
436 	 * we must search through all routes unless we find a
437 	 * host route, because some host routes might overlap
438 	 * network routes
439 	 */
440 	struct atalk_route *net_route = NULL;
441 	struct atalk_route *r;
442 
443 	read_lock_bh(&atalk_routes_lock);
444 	for (r = atalk_routes; r; r = r->next) {
445 		if (!(r->flags & RTF_UP))
446 			continue;
447 
448 		if (r->target.s_net == target->s_net) {
449 			if (r->flags & RTF_HOST) {
450 				/*
451 				 * if this host route is for the target,
452 				 * the we're done
453 				 */
454 				if (r->target.s_node == target->s_node)
455 					goto out;
456 			} else
457 				/*
458 				 * this route will work if there isn't a
459 				 * direct host route, so cache it
460 				 */
461 				net_route = r;
462 		}
463 	}
464 
465 	/*
466 	 * if we found a network route but not a direct host
467 	 * route, then return it
468 	 */
469 	if (net_route)
470 		r = net_route;
471 	else if (atrtr_default.dev)
472 		r = &atrtr_default;
473 	else /* No route can be found */
474 		r = NULL;
475 out:
476 	read_unlock_bh(&atalk_routes_lock);
477 	return r;
478 }
479 
480 
481 /*
482  * Given an AppleTalk network, find the device to use. This can be
483  * a simple lookup.
484  */
485 struct net_device *atrtr_get_dev(struct atalk_addr *sa)
486 {
487 	struct atalk_route *atr = atrtr_find(sa);
488 	return atr ? atr->dev : NULL;
489 }
490 
491 /* Set up a default router */
492 static void atrtr_set_default(struct net_device *dev)
493 {
494 	atrtr_default.dev	     = dev;
495 	atrtr_default.flags	     = RTF_UP;
496 	atrtr_default.gateway.s_net  = htons(0);
497 	atrtr_default.gateway.s_node = 0;
498 }
499 
500 /*
501  * Add a router. Basically make sure it looks valid and stuff the
502  * entry in the list. While it uses netranges we always set them to one
503  * entry to work like netatalk.
504  */
505 static int atrtr_create(struct rtentry *r, struct net_device *devhint)
506 {
507 	struct sockaddr_at *ta = (struct sockaddr_at *)&r->rt_dst;
508 	struct sockaddr_at *ga = (struct sockaddr_at *)&r->rt_gateway;
509 	struct atalk_route *rt;
510 	struct atalk_iface *iface, *riface;
511 	int retval = -EINVAL;
512 
513 	/*
514 	 * Fixme: Raise/Lower a routing change semaphore for these
515 	 * operations.
516 	 */
517 
518 	/* Validate the request */
519 	if (ta->sat_family != AF_APPLETALK ||
520 	    (!devhint && ga->sat_family != AF_APPLETALK))
521 		goto out;
522 
523 	/* Now walk the routing table and make our decisions */
524 	write_lock_bh(&atalk_routes_lock);
525 	for (rt = atalk_routes; rt; rt = rt->next) {
526 		if (r->rt_flags != rt->flags)
527 			continue;
528 
529 		if (ta->sat_addr.s_net == rt->target.s_net) {
530 			if (!(rt->flags & RTF_HOST))
531 				break;
532 			if (ta->sat_addr.s_node == rt->target.s_node)
533 				break;
534 		}
535 	}
536 
537 	if (!devhint) {
538 		riface = NULL;
539 
540 		read_lock_bh(&atalk_interfaces_lock);
541 		for (iface = atalk_interfaces; iface; iface = iface->next) {
542 			if (!riface &&
543 			    ntohs(ga->sat_addr.s_net) >=
544 			    		ntohs(iface->nets.nr_firstnet) &&
545 			    ntohs(ga->sat_addr.s_net) <=
546 			    		ntohs(iface->nets.nr_lastnet))
547 				riface = iface;
548 
549 			if (ga->sat_addr.s_net == iface->address.s_net &&
550 			    ga->sat_addr.s_node == iface->address.s_node)
551 				riface = iface;
552 		}
553 		read_unlock_bh(&atalk_interfaces_lock);
554 
555 		retval = -ENETUNREACH;
556 		if (!riface)
557 			goto out_unlock;
558 
559 		devhint = riface->dev;
560 	}
561 
562 	if (!rt) {
563 		rt = kmalloc(sizeof(*rt), GFP_ATOMIC);
564 
565 		retval = -ENOBUFS;
566 		if (!rt)
567 			goto out_unlock;
568 		memset(rt, 0, sizeof(*rt));
569 
570 		rt->next = atalk_routes;
571 		atalk_routes = rt;
572 	}
573 
574 	/* Fill in the routing entry */
575 	rt->target  = ta->sat_addr;
576 	dev_hold(devhint);
577 	rt->dev     = devhint;
578 	rt->flags   = r->rt_flags;
579 	rt->gateway = ga->sat_addr;
580 
581 	retval = 0;
582 out_unlock:
583 	write_unlock_bh(&atalk_routes_lock);
584 out:
585 	return retval;
586 }
587 
588 /* Delete a route. Find it and discard it */
589 static int atrtr_delete(struct atalk_addr * addr)
590 {
591 	struct atalk_route **r = &atalk_routes;
592 	int retval = 0;
593 	struct atalk_route *tmp;
594 
595 	write_lock_bh(&atalk_routes_lock);
596 	while ((tmp = *r) != NULL) {
597 		if (tmp->target.s_net == addr->s_net &&
598 		    (!(tmp->flags&RTF_GATEWAY) ||
599 		     tmp->target.s_node == addr->s_node)) {
600 			*r = tmp->next;
601 			dev_put(tmp->dev);
602 			kfree(tmp);
603 			goto out;
604 		}
605 		r = &tmp->next;
606 	}
607 	retval = -ENOENT;
608 out:
609 	write_unlock_bh(&atalk_routes_lock);
610 	return retval;
611 }
612 
613 /*
614  * Called when a device is downed. Just throw away any routes
615  * via it.
616  */
617 static void atrtr_device_down(struct net_device *dev)
618 {
619 	struct atalk_route **r = &atalk_routes;
620 	struct atalk_route *tmp;
621 
622 	write_lock_bh(&atalk_routes_lock);
623 	while ((tmp = *r) != NULL) {
624 		if (tmp->dev == dev) {
625 			*r = tmp->next;
626 			dev_put(dev);
627 			kfree(tmp);
628 		} else
629 			r = &tmp->next;
630 	}
631 	write_unlock_bh(&atalk_routes_lock);
632 
633 	if (atrtr_default.dev == dev)
634 		atrtr_set_default(NULL);
635 }
636 
637 /* Actually down the interface */
638 static inline void atalk_dev_down(struct net_device *dev)
639 {
640 	atrtr_device_down(dev);	/* Remove all routes for the device */
641 	aarp_device_down(dev);	/* Remove AARP entries for the device */
642 	atif_drop_device(dev);	/* Remove the device */
643 }
644 
645 /*
646  * A device event has occurred. Watch for devices going down and
647  * delete our use of them (iface and route).
648  */
649 static int ddp_device_event(struct notifier_block *this, unsigned long event,
650 			    void *ptr)
651 {
652 	if (event == NETDEV_DOWN)
653 		/* Discard any use of this */
654 	        atalk_dev_down(ptr);
655 
656 	return NOTIFY_DONE;
657 }
658 
659 /* ioctl calls. Shouldn't even need touching */
660 /* Device configuration ioctl calls */
661 static int atif_ioctl(int cmd, void __user *arg)
662 {
663 	static char aarp_mcast[6] = { 0x09, 0x00, 0x00, 0xFF, 0xFF, 0xFF };
664 	struct ifreq atreq;
665 	struct atalk_netrange *nr;
666 	struct sockaddr_at *sa;
667 	struct net_device *dev;
668 	struct atalk_iface *atif;
669 	int ct;
670 	int limit;
671 	struct rtentry rtdef;
672 	int add_route;
673 
674 	if (copy_from_user(&atreq, arg, sizeof(atreq)))
675 		return -EFAULT;
676 
677 	dev = __dev_get_by_name(atreq.ifr_name);
678 	if (!dev)
679 		return -ENODEV;
680 
681 	sa = (struct sockaddr_at *)&atreq.ifr_addr;
682 	atif = atalk_find_dev(dev);
683 
684 	switch (cmd) {
685 		case SIOCSIFADDR:
686 			if (!capable(CAP_NET_ADMIN))
687 				return -EPERM;
688 			if (sa->sat_family != AF_APPLETALK)
689 				return -EINVAL;
690 			if (dev->type != ARPHRD_ETHER &&
691 			    dev->type != ARPHRD_LOOPBACK &&
692 			    dev->type != ARPHRD_LOCALTLK &&
693 			    dev->type != ARPHRD_PPP)
694 				return -EPROTONOSUPPORT;
695 
696 			nr = (struct atalk_netrange *)&sa->sat_zero[0];
697 			add_route = 1;
698 
699 			/*
700 			 * if this is a point-to-point iface, and we already
701 			 * have an iface for this AppleTalk address, then we
702 			 * should not add a route
703 			 */
704 			if ((dev->flags & IFF_POINTOPOINT) &&
705 			    atalk_find_interface(sa->sat_addr.s_net,
706 				    		 sa->sat_addr.s_node)) {
707 				printk(KERN_DEBUG "AppleTalk: point-to-point "
708 						  "interface added with "
709 						  "existing address\n");
710 				add_route = 0;
711 			}
712 
713 			/*
714 			 * Phase 1 is fine on LocalTalk but we don't do
715 			 * EtherTalk phase 1. Anyone wanting to add it go ahead.
716 			 */
717 			if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
718 				return -EPROTONOSUPPORT;
719 			if (sa->sat_addr.s_node == ATADDR_BCAST ||
720 			    sa->sat_addr.s_node == 254)
721 				return -EINVAL;
722 			if (atif) {
723 				/* Already setting address */
724 				if (atif->status & ATIF_PROBE)
725 					return -EBUSY;
726 
727 				atif->address.s_net  = sa->sat_addr.s_net;
728 				atif->address.s_node = sa->sat_addr.s_node;
729 				atrtr_device_down(dev);	/* Flush old routes */
730 			} else {
731 				atif = atif_add_device(dev, &sa->sat_addr);
732 				if (!atif)
733 					return -ENOMEM;
734 			}
735 			atif->nets = *nr;
736 
737 			/*
738 			 * Check if the chosen address is used. If so we
739 			 * error and atalkd will try another.
740 			 */
741 
742 			if (!(dev->flags & IFF_LOOPBACK) &&
743 			    !(dev->flags & IFF_POINTOPOINT) &&
744 			    atif_probe_device(atif) < 0) {
745 				atif_drop_device(dev);
746 				return -EADDRINUSE;
747 			}
748 
749 			/* Hey it worked - add the direct routes */
750 			sa = (struct sockaddr_at *)&rtdef.rt_gateway;
751 			sa->sat_family = AF_APPLETALK;
752 			sa->sat_addr.s_net  = atif->address.s_net;
753 			sa->sat_addr.s_node = atif->address.s_node;
754 			sa = (struct sockaddr_at *)&rtdef.rt_dst;
755 			rtdef.rt_flags = RTF_UP;
756 			sa->sat_family = AF_APPLETALK;
757 			sa->sat_addr.s_node = ATADDR_ANYNODE;
758 			if (dev->flags & IFF_LOOPBACK ||
759 			    dev->flags & IFF_POINTOPOINT)
760 				rtdef.rt_flags |= RTF_HOST;
761 
762 			/* Routerless initial state */
763 			if (nr->nr_firstnet == htons(0) &&
764 			    nr->nr_lastnet == htons(0xFFFE)) {
765 				sa->sat_addr.s_net = atif->address.s_net;
766 				atrtr_create(&rtdef, dev);
767 				atrtr_set_default(dev);
768 			} else {
769 				limit = ntohs(nr->nr_lastnet);
770 				if (limit - ntohs(nr->nr_firstnet) > 4096) {
771 					printk(KERN_WARNING "Too many routes/"
772 							    "iface.\n");
773 					return -EINVAL;
774 				}
775 				if (add_route)
776 					for (ct = ntohs(nr->nr_firstnet);
777 					     ct <= limit; ct++) {
778 						sa->sat_addr.s_net = htons(ct);
779 						atrtr_create(&rtdef, dev);
780 					}
781 			}
782 			dev_mc_add(dev, aarp_mcast, 6, 1);
783 			return 0;
784 
785 		case SIOCGIFADDR:
786 			if (!atif)
787 				return -EADDRNOTAVAIL;
788 
789 			sa->sat_family = AF_APPLETALK;
790 			sa->sat_addr = atif->address;
791 			break;
792 
793 		case SIOCGIFBRDADDR:
794 			if (!atif)
795 				return -EADDRNOTAVAIL;
796 
797 			sa->sat_family = AF_APPLETALK;
798 			sa->sat_addr.s_net = atif->address.s_net;
799 			sa->sat_addr.s_node = ATADDR_BCAST;
800 			break;
801 
802 	        case SIOCATALKDIFADDR:
803 	        case SIOCDIFADDR:
804 			if (!capable(CAP_NET_ADMIN))
805 				return -EPERM;
806 			if (sa->sat_family != AF_APPLETALK)
807 				return -EINVAL;
808 			atalk_dev_down(dev);
809 			break;
810 
811 		case SIOCSARP:
812 			if (!capable(CAP_NET_ADMIN))
813                                 return -EPERM;
814                         if (sa->sat_family != AF_APPLETALK)
815                                 return -EINVAL;
816                         if (!atif)
817                                 return -EADDRNOTAVAIL;
818 
819                         /*
820                          * for now, we only support proxy AARP on ELAP;
821                          * we should be able to do it for LocalTalk, too.
822                          */
823                         if (dev->type != ARPHRD_ETHER)
824                                 return -EPROTONOSUPPORT;
825 
826                         /*
827                          * atif points to the current interface on this network;
828                          * we aren't concerned about its current status (at
829 			 * least for now), but it has all the settings about
830 			 * the network we're going to probe. Consequently, it
831 			 * must exist.
832                          */
833                         if (!atif)
834                                 return -EADDRNOTAVAIL;
835 
836                         nr = (struct atalk_netrange *)&(atif->nets);
837                         /*
838                          * Phase 1 is fine on Localtalk but we don't do
839                          * Ethertalk phase 1. Anyone wanting to add it go ahead.
840                          */
841                         if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
842                                 return -EPROTONOSUPPORT;
843 
844                         if (sa->sat_addr.s_node == ATADDR_BCAST ||
845 			    sa->sat_addr.s_node == 254)
846                                 return -EINVAL;
847 
848                         /*
849                          * Check if the chosen address is used. If so we
850                          * error and ATCP will try another.
851                          */
852                       	if (atif_proxy_probe_device(atif, &(sa->sat_addr)) < 0)
853                       		return -EADDRINUSE;
854 
855 			/*
856                          * We now have an address on the local network, and
857 			 * the AARP code will defend it for us until we take it
858 			 * down. We don't set up any routes right now, because
859 			 * ATCP will install them manually via SIOCADDRT.
860                          */
861                         break;
862 
863                 case SIOCDARP:
864                         if (!capable(CAP_NET_ADMIN))
865                                 return -EPERM;
866                         if (sa->sat_family != AF_APPLETALK)
867                                 return -EINVAL;
868                         if (!atif)
869                                 return -EADDRNOTAVAIL;
870 
871                         /* give to aarp module to remove proxy entry */
872                         aarp_proxy_remove(atif->dev, &(sa->sat_addr));
873                         return 0;
874 	}
875 
876 	return copy_to_user(arg, &atreq, sizeof(atreq)) ? -EFAULT : 0;
877 }
878 
879 /* Routing ioctl() calls */
880 static int atrtr_ioctl(unsigned int cmd, void __user *arg)
881 {
882 	struct rtentry rt;
883 
884 	if (copy_from_user(&rt, arg, sizeof(rt)))
885 		return -EFAULT;
886 
887 	switch (cmd) {
888 		case SIOCDELRT:
889 			if (rt.rt_dst.sa_family != AF_APPLETALK)
890 				return -EINVAL;
891 			return atrtr_delete(&((struct sockaddr_at *)
892 						&rt.rt_dst)->sat_addr);
893 
894 		case SIOCADDRT: {
895 			struct net_device *dev = NULL;
896 			if (rt.rt_dev) {
897 				char name[IFNAMSIZ];
898 				if (copy_from_user(name, rt.rt_dev, IFNAMSIZ-1))
899 					return -EFAULT;
900 				name[IFNAMSIZ-1] = '\0';
901 				dev = __dev_get_by_name(name);
902 				if (!dev)
903 					return -ENODEV;
904 			}
905 			return atrtr_create(&rt, dev);
906 		}
907 	}
908 	return -EINVAL;
909 }
910 
911 /**************************************************************************\
912 *                                                                          *
913 * Handling for system calls applied via the various interfaces to an       *
914 * AppleTalk socket object.                                                 *
915 *                                                                          *
916 \**************************************************************************/
917 
918 /*
919  * Checksum: This is 'optional'. It's quite likely also a good
920  * candidate for assembler hackery 8)
921  */
922 static unsigned long atalk_sum_partial(const unsigned char *data,
923 				       int len, unsigned long sum)
924 {
925 	/* This ought to be unwrapped neatly. I'll trust gcc for now */
926 	while (len--) {
927 		sum += *data;
928 		sum <<= 1;
929 		if (sum & 0x10000) {
930 			sum++;
931 			sum &= 0xffff;
932 		}
933 		data++;
934 	}
935 	return sum;
936 }
937 
938 /*  Checksum skb data --  similar to skb_checksum  */
939 static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
940 				   int len, unsigned long sum)
941 {
942 	int start = skb_headlen(skb);
943 	int i, copy;
944 
945 	/* checksum stuff in header space */
946 	if ( (copy = start - offset) > 0) {
947 		if (copy > len)
948 			copy = len;
949 		sum = atalk_sum_partial(skb->data + offset, copy, sum);
950 		if ( (len -= copy) == 0)
951 			return sum;
952 
953 		offset += copy;
954 	}
955 
956 	/* checksum stuff in frags */
957 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
958 		int end;
959 
960 		BUG_TRAP(start <= offset + len);
961 
962 		end = start + skb_shinfo(skb)->frags[i].size;
963 		if ((copy = end - offset) > 0) {
964 			u8 *vaddr;
965 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
966 
967 			if (copy > len)
968 				copy = len;
969 			vaddr = kmap_skb_frag(frag);
970 			sum = atalk_sum_partial(vaddr + frag->page_offset +
971 						  offset - start, copy, sum);
972 			kunmap_skb_frag(vaddr);
973 
974 			if (!(len -= copy))
975 				return sum;
976 			offset += copy;
977 		}
978 		start = end;
979 	}
980 
981 	if (skb_shinfo(skb)->frag_list) {
982 		struct sk_buff *list = skb_shinfo(skb)->frag_list;
983 
984 		for (; list; list = list->next) {
985 			int end;
986 
987 			BUG_TRAP(start <= offset + len);
988 
989 			end = start + list->len;
990 			if ((copy = end - offset) > 0) {
991 				if (copy > len)
992 					copy = len;
993 				sum = atalk_sum_skb(list, offset - start,
994 						    copy, sum);
995 				if ((len -= copy) == 0)
996 					return sum;
997 				offset += copy;
998 			}
999 			start = end;
1000 		}
1001 	}
1002 
1003 	BUG_ON(len > 0);
1004 
1005 	return sum;
1006 }
1007 
1008 static unsigned short atalk_checksum(const struct sk_buff *skb, int len)
1009 {
1010 	unsigned long sum;
1011 
1012 	/* skip header 4 bytes */
1013 	sum = atalk_sum_skb(skb, 4, len-4, 0);
1014 
1015 	/* Use 0xFFFF for 0. 0 itself means none */
1016 	return sum ? htons((unsigned short)sum) : 0xFFFF;
1017 }
1018 
1019 static struct proto ddp_proto = {
1020 	.name	  = "DDP",
1021 	.owner	  = THIS_MODULE,
1022 	.obj_size = sizeof(struct atalk_sock),
1023 };
1024 
1025 /*
1026  * Create a socket. Initialise the socket, blank the addresses
1027  * set the state.
1028  */
1029 static int atalk_create(struct socket *sock, int protocol)
1030 {
1031 	struct sock *sk;
1032 	int rc = -ESOCKTNOSUPPORT;
1033 
1034 	/*
1035 	 * We permit SOCK_DGRAM and RAW is an extension. It is trivial to do
1036 	 * and gives you the full ELAP frame. Should be handy for CAP 8)
1037 	 */
1038 	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
1039 		goto out;
1040 	rc = -ENOMEM;
1041 	sk = sk_alloc(PF_APPLETALK, GFP_KERNEL, &ddp_proto, 1);
1042 	if (!sk)
1043 		goto out;
1044 	rc = 0;
1045 	sock->ops = &atalk_dgram_ops;
1046 	sock_init_data(sock, sk);
1047 
1048 	/* Checksums on by default */
1049 	sock_set_flag(sk, SOCK_ZAPPED);
1050 out:
1051 	return rc;
1052 }
1053 
1054 /* Free a socket. No work needed */
1055 static int atalk_release(struct socket *sock)
1056 {
1057 	struct sock *sk = sock->sk;
1058 
1059 	if (sk) {
1060 		sock_orphan(sk);
1061 		sock->sk = NULL;
1062 		atalk_destroy_socket(sk);
1063 	}
1064 	return 0;
1065 }
1066 
1067 /**
1068  * atalk_pick_and_bind_port - Pick a source port when one is not given
1069  * @sk - socket to insert into the tables
1070  * @sat - address to search for
1071  *
1072  * Pick a source port when one is not given. If we can find a suitable free
1073  * one, we insert the socket into the tables using it.
1074  *
1075  * This whole operation must be atomic.
1076  */
1077 static int atalk_pick_and_bind_port(struct sock *sk, struct sockaddr_at *sat)
1078 {
1079 	int retval;
1080 
1081 	write_lock_bh(&atalk_sockets_lock);
1082 
1083 	for (sat->sat_port = ATPORT_RESERVED;
1084 	     sat->sat_port < ATPORT_LAST;
1085 	     sat->sat_port++) {
1086 		struct sock *s;
1087 		struct hlist_node *node;
1088 
1089 		sk_for_each(s, node, &atalk_sockets) {
1090 			struct atalk_sock *at = at_sk(s);
1091 
1092 			if (at->src_net == sat->sat_addr.s_net &&
1093 			    at->src_node == sat->sat_addr.s_node &&
1094 			    at->src_port == sat->sat_port)
1095 				goto try_next_port;
1096 		}
1097 
1098 		/* Wheee, it's free, assign and insert. */
1099 		__atalk_insert_socket(sk);
1100 		at_sk(sk)->src_port = sat->sat_port;
1101 		retval = 0;
1102 		goto out;
1103 
1104 try_next_port:;
1105 	}
1106 
1107 	retval = -EBUSY;
1108 out:
1109 	write_unlock_bh(&atalk_sockets_lock);
1110 	return retval;
1111 }
1112 
1113 static int atalk_autobind(struct sock *sk)
1114 {
1115 	struct atalk_sock *at = at_sk(sk);
1116 	struct sockaddr_at sat;
1117 	struct atalk_addr *ap = atalk_find_primary();
1118 	int n = -EADDRNOTAVAIL;
1119 
1120 	if (!ap || ap->s_net == htons(ATADDR_ANYNET))
1121 		goto out;
1122 
1123 	at->src_net  = sat.sat_addr.s_net  = ap->s_net;
1124 	at->src_node = sat.sat_addr.s_node = ap->s_node;
1125 
1126 	n = atalk_pick_and_bind_port(sk, &sat);
1127 	if (!n)
1128 		sock_reset_flag(sk, SOCK_ZAPPED);
1129 out:
1130 	return n;
1131 }
1132 
1133 /* Set the address 'our end' of the connection */
1134 static int atalk_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1135 {
1136 	struct sockaddr_at *addr = (struct sockaddr_at *)uaddr;
1137 	struct sock *sk = sock->sk;
1138 	struct atalk_sock *at = at_sk(sk);
1139 
1140 	if (!sock_flag(sk, SOCK_ZAPPED) ||
1141 	    addr_len != sizeof(struct sockaddr_at))
1142 		return -EINVAL;
1143 
1144 	if (addr->sat_family != AF_APPLETALK)
1145 		return -EAFNOSUPPORT;
1146 
1147 	if (addr->sat_addr.s_net == htons(ATADDR_ANYNET)) {
1148 		struct atalk_addr *ap = atalk_find_primary();
1149 
1150 		if (!ap)
1151 			return -EADDRNOTAVAIL;
1152 
1153 		at->src_net  = addr->sat_addr.s_net = ap->s_net;
1154 		at->src_node = addr->sat_addr.s_node= ap->s_node;
1155 	} else {
1156 		if (!atalk_find_interface(addr->sat_addr.s_net,
1157 					  addr->sat_addr.s_node))
1158 			return -EADDRNOTAVAIL;
1159 
1160 		at->src_net  = addr->sat_addr.s_net;
1161 		at->src_node = addr->sat_addr.s_node;
1162 	}
1163 
1164 	if (addr->sat_port == ATADDR_ANYPORT) {
1165 		int n = atalk_pick_and_bind_port(sk, addr);
1166 
1167 		if (n < 0)
1168 			return n;
1169 	} else {
1170 		at->src_port = addr->sat_port;
1171 
1172 		if (atalk_find_or_insert_socket(sk, addr))
1173 			return -EADDRINUSE;
1174 	}
1175 
1176 	sock_reset_flag(sk, SOCK_ZAPPED);
1177 	return 0;
1178 }
1179 
1180 /* Set the address we talk to */
1181 static int atalk_connect(struct socket *sock, struct sockaddr *uaddr,
1182 			 int addr_len, int flags)
1183 {
1184 	struct sock *sk = sock->sk;
1185 	struct atalk_sock *at = at_sk(sk);
1186 	struct sockaddr_at *addr;
1187 
1188 	sk->sk_state   = TCP_CLOSE;
1189 	sock->state = SS_UNCONNECTED;
1190 
1191 	if (addr_len != sizeof(*addr))
1192 		return -EINVAL;
1193 
1194 	addr = (struct sockaddr_at *)uaddr;
1195 
1196 	if (addr->sat_family != AF_APPLETALK)
1197 		return -EAFNOSUPPORT;
1198 
1199 	if (addr->sat_addr.s_node == ATADDR_BCAST &&
1200 	    !sock_flag(sk, SOCK_BROADCAST)) {
1201 #if 1
1202 		printk(KERN_WARNING "%s is broken and did not set "
1203 				    "SO_BROADCAST. It will break when 2.2 is "
1204 				    "released.\n",
1205 			current->comm);
1206 #else
1207 		return -EACCES;
1208 #endif
1209 	}
1210 
1211 	if (sock_flag(sk, SOCK_ZAPPED))
1212 		if (atalk_autobind(sk) < 0)
1213 			return -EBUSY;
1214 
1215 	if (!atrtr_get_dev(&addr->sat_addr))
1216 		return -ENETUNREACH;
1217 
1218 	at->dest_port = addr->sat_port;
1219 	at->dest_net  = addr->sat_addr.s_net;
1220 	at->dest_node = addr->sat_addr.s_node;
1221 
1222 	sock->state  = SS_CONNECTED;
1223 	sk->sk_state = TCP_ESTABLISHED;
1224 	return 0;
1225 }
1226 
1227 /*
1228  * Find the name of an AppleTalk socket. Just copy the right
1229  * fields into the sockaddr.
1230  */
1231 static int atalk_getname(struct socket *sock, struct sockaddr *uaddr,
1232 			 int *uaddr_len, int peer)
1233 {
1234 	struct sockaddr_at sat;
1235 	struct sock *sk = sock->sk;
1236 	struct atalk_sock *at = at_sk(sk);
1237 
1238 	if (sock_flag(sk, SOCK_ZAPPED))
1239 		if (atalk_autobind(sk) < 0)
1240 			return -ENOBUFS;
1241 
1242 	*uaddr_len = sizeof(struct sockaddr_at);
1243 
1244 	if (peer) {
1245 		if (sk->sk_state != TCP_ESTABLISHED)
1246 			return -ENOTCONN;
1247 
1248 		sat.sat_addr.s_net  = at->dest_net;
1249 		sat.sat_addr.s_node = at->dest_node;
1250 		sat.sat_port	    = at->dest_port;
1251 	} else {
1252 		sat.sat_addr.s_net  = at->src_net;
1253 		sat.sat_addr.s_node = at->src_node;
1254 		sat.sat_port	    = at->src_port;
1255 	}
1256 
1257 	sat.sat_family = AF_APPLETALK;
1258 	memcpy(uaddr, &sat, sizeof(sat));
1259 	return 0;
1260 }
1261 
1262 #if defined(CONFIG_IPDDP) || defined(CONFIG_IPDDP_MODULE)
1263 static __inline__ int is_ip_over_ddp(struct sk_buff *skb)
1264 {
1265         return skb->data[12] == 22;
1266 }
1267 
1268 static int handle_ip_over_ddp(struct sk_buff *skb)
1269 {
1270         struct net_device *dev = __dev_get_by_name("ipddp0");
1271 	struct net_device_stats *stats;
1272 
1273 	/* This needs to be able to handle ipddp"N" devices */
1274         if (!dev)
1275                 return -ENODEV;
1276 
1277         skb->protocol = htons(ETH_P_IP);
1278         skb_pull(skb, 13);
1279         skb->dev   = dev;
1280         skb->h.raw = skb->data;
1281 
1282 	stats = dev->priv;
1283         stats->rx_packets++;
1284         stats->rx_bytes += skb->len + 13;
1285         netif_rx(skb);  /* Send the SKB up to a higher place. */
1286 	return 0;
1287 }
1288 #else
1289 /* make it easy for gcc to optimize this test out, i.e. kill the code */
1290 #define is_ip_over_ddp(skb) 0
1291 #define handle_ip_over_ddp(skb) 0
1292 #endif
1293 
1294 static void atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
1295 			       struct ddpehdr *ddp, struct ddpebits *ddphv,
1296 			       int origlen)
1297 {
1298 	struct atalk_route *rt;
1299 	struct atalk_addr ta;
1300 
1301 	/*
1302 	 * Don't route multicast, etc., packets, or packets sent to "this
1303 	 * network"
1304 	 */
1305 	if (skb->pkt_type != PACKET_HOST || !ddp->deh_dnet) {
1306 		/*
1307 		 * FIXME:
1308 		 *
1309 		 * Can it ever happen that a packet is from a PPP iface and
1310 		 * needs to be broadcast onto the default network?
1311 		 */
1312 		if (dev->type == ARPHRD_PPP)
1313 			printk(KERN_DEBUG "AppleTalk: didn't forward broadcast "
1314 					  "packet received from PPP iface\n");
1315 		goto free_it;
1316 	}
1317 
1318 	ta.s_net  = ddp->deh_dnet;
1319 	ta.s_node = ddp->deh_dnode;
1320 
1321 	/* Route the packet */
1322 	rt = atrtr_find(&ta);
1323 	if (!rt || ddphv->deh_hops == DDP_MAXHOPS)
1324 		goto free_it;
1325 	/* FIXME: use skb->cb to be able to use shared skbs */
1326 	ddphv->deh_hops++;
1327 
1328 	/*
1329 	 * Route goes through another gateway, so set the target to the
1330 	 * gateway instead.
1331 	 */
1332 
1333 	if (rt->flags & RTF_GATEWAY) {
1334 		ta.s_net  = rt->gateway.s_net;
1335 		ta.s_node = rt->gateway.s_node;
1336 	}
1337 
1338         /* Fix up skb->len field */
1339         skb_trim(skb, min_t(unsigned int, origlen,
1340 			    (rt->dev->hard_header_len +
1341 			     ddp_dl->header_length + ddphv->deh_len)));
1342 
1343 	/* Mend the byte order */
1344 	/* FIXME: use skb->cb to be able to use shared skbs */
1345 	*((__u16 *)ddp) = ntohs(*((__u16 *)ddphv));
1346 
1347 	/*
1348 	 * Send the buffer onwards
1349 	 *
1350 	 * Now we must always be careful. If it's come from LocalTalk to
1351 	 * EtherTalk it might not fit
1352 	 *
1353 	 * Order matters here: If a packet has to be copied to make a new
1354 	 * headroom (rare hopefully) then it won't need unsharing.
1355 	 *
1356 	 * Note. ddp-> becomes invalid at the realloc.
1357 	 */
1358 	if (skb_headroom(skb) < 22) {
1359 		/* 22 bytes - 12 ether, 2 len, 3 802.2 5 snap */
1360 		struct sk_buff *nskb = skb_realloc_headroom(skb, 32);
1361 		kfree_skb(skb);
1362 		if (!nskb)
1363 			goto out;
1364 		skb = nskb;
1365 	} else
1366 		skb = skb_unshare(skb, GFP_ATOMIC);
1367 
1368 	/*
1369 	 * If the buffer didn't vanish into the lack of space bitbucket we can
1370 	 * send it.
1371 	 */
1372 	if (skb && aarp_send_ddp(rt->dev, skb, &ta, NULL) == -1)
1373 		goto free_it;
1374 out:
1375 	return;
1376 free_it:
1377 	kfree_skb(skb);
1378 }
1379 
1380 /**
1381  *	atalk_rcv - Receive a packet (in skb) from device dev
1382  *	@skb - packet received
1383  *	@dev - network device where the packet comes from
1384  *	@pt - packet type
1385  *
1386  *	Receive a packet (in skb) from device dev. This has come from the SNAP
1387  *	decoder, and on entry skb->h.raw is the DDP header, skb->len is the DDP
1388  *	header, skb->len is the DDP length. The physical headers have been
1389  *	extracted. PPP should probably pass frames marked as for this layer.
1390  *	[ie ARPHRD_ETHERTALK]
1391  */
1392 static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
1393 		     struct packet_type *pt, struct net_device *orig_dev)
1394 {
1395 	struct ddpehdr *ddp;
1396 	struct sock *sock;
1397 	struct atalk_iface *atif;
1398 	struct sockaddr_at tosat;
1399         int origlen;
1400         struct ddpebits ddphv;
1401 
1402 	/* Don't mangle buffer if shared */
1403 	if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
1404 		goto out;
1405 
1406 	/* Size check and make sure header is contiguous */
1407 	if (!pskb_may_pull(skb, sizeof(*ddp)))
1408 		goto freeit;
1409 
1410 	ddp = ddp_hdr(skb);
1411 
1412 	/*
1413 	 *	Fix up the length field	[Ok this is horrible but otherwise
1414 	 *	I end up with unions of bit fields and messy bit field order
1415 	 *	compiler/endian dependencies..]
1416 	 */
1417 	*((__u16 *)&ddphv) = ntohs(*((__u16 *)ddp));
1418 
1419 	/* Trim buffer in case of stray trailing data */
1420 	origlen = skb->len;
1421 	skb_trim(skb, min_t(unsigned int, skb->len, ddphv.deh_len));
1422 
1423 	/*
1424 	 * Size check to see if ddp->deh_len was crap
1425 	 * (Otherwise we'll detonate most spectacularly
1426 	 * in the middle of recvmsg()).
1427 	 */
1428 	if (skb->len < sizeof(*ddp))
1429 		goto freeit;
1430 
1431 	/*
1432 	 * Any checksums. Note we don't do htons() on this == is assumed to be
1433 	 * valid for net byte orders all over the networking code...
1434 	 */
1435 	if (ddp->deh_sum &&
1436 	    atalk_checksum(skb, ddphv.deh_len) != ddp->deh_sum)
1437 		/* Not a valid AppleTalk frame - dustbin time */
1438 		goto freeit;
1439 
1440 	/* Check the packet is aimed at us */
1441 	if (!ddp->deh_dnet)	/* Net 0 is 'this network' */
1442 		atif = atalk_find_anynet(ddp->deh_dnode, dev);
1443 	else
1444 		atif = atalk_find_interface(ddp->deh_dnet, ddp->deh_dnode);
1445 
1446 	if (!atif) {
1447 		/* Not ours, so we route the packet via the correct
1448 		 * AppleTalk iface
1449 		 */
1450 		atalk_route_packet(skb, dev, ddp, &ddphv, origlen);
1451 		goto out;
1452 	}
1453 
1454 	/* if IP over DDP is not selected this code will be optimized out */
1455 	if (is_ip_over_ddp(skb))
1456 		return handle_ip_over_ddp(skb);
1457 	/*
1458 	 * Which socket - atalk_search_socket() looks for a *full match*
1459 	 * of the <net, node, port> tuple.
1460 	 */
1461 	tosat.sat_addr.s_net  = ddp->deh_dnet;
1462 	tosat.sat_addr.s_node = ddp->deh_dnode;
1463 	tosat.sat_port	      = ddp->deh_dport;
1464 
1465 	sock = atalk_search_socket(&tosat, atif);
1466 	if (!sock) /* But not one of our sockets */
1467 		goto freeit;
1468 
1469 	/* Queue packet (standard) */
1470 	skb->sk = sock;
1471 
1472 	if (sock_queue_rcv_skb(sock, skb) < 0)
1473 		goto freeit;
1474 out:
1475 	return 0;
1476 freeit:
1477 	kfree_skb(skb);
1478 	goto out;
1479 }
1480 
1481 /*
1482  * Receive a LocalTalk frame. We make some demands on the caller here.
1483  * Caller must provide enough headroom on the packet to pull the short
1484  * header and append a long one.
1485  */
1486 static int ltalk_rcv(struct sk_buff *skb, struct net_device *dev,
1487 		     struct packet_type *pt, struct net_device *orig_dev)
1488 {
1489 	/* Expand any short form frames */
1490 	if (skb->mac.raw[2] == 1) {
1491 		struct ddpehdr *ddp;
1492 		/* Find our address */
1493 		struct atalk_addr *ap = atalk_find_dev_addr(dev);
1494 
1495 		if (!ap || skb->len < sizeof(struct ddpshdr))
1496 			goto freeit;
1497 
1498 		/* Don't mangle buffer if shared */
1499 		if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
1500 			return 0;
1501 
1502 		/*
1503 		 * The push leaves us with a ddephdr not an shdr, and
1504 		 * handily the port bytes in the right place preset.
1505 		 */
1506 		ddp = (struct ddpehdr *) skb_push(skb, sizeof(*ddp) - 4);
1507 
1508 		/* Now fill in the long header */
1509 
1510 	 	/*
1511 	 	 * These two first. The mac overlays the new source/dest
1512 	 	 * network information so we MUST copy these before
1513 	 	 * we write the network numbers !
1514 	 	 */
1515 
1516 		ddp->deh_dnode = skb->mac.raw[0];     /* From physical header */
1517 		ddp->deh_snode = skb->mac.raw[1];     /* From physical header */
1518 
1519 		ddp->deh_dnet  = ap->s_net;	/* Network number */
1520 		ddp->deh_snet  = ap->s_net;
1521 		ddp->deh_sum   = 0;		/* No checksum */
1522 		/*
1523 		 * Not sure about this bit...
1524 		 */
1525 		ddp->deh_len   = skb->len;
1526 		ddp->deh_hops  = DDP_MAXHOPS;	/* Non routable, so force a drop
1527 						   if we slip up later */
1528 		/* Mend the byte order */
1529 		*((__u16 *)ddp) = htons(*((__u16 *)ddp));
1530 	}
1531 	skb->h.raw = skb->data;
1532 
1533 	return atalk_rcv(skb, dev, pt, orig_dev);
1534 freeit:
1535 	kfree_skb(skb);
1536 	return 0;
1537 }
1538 
1539 static int atalk_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
1540 			 size_t len)
1541 {
1542 	struct sock *sk = sock->sk;
1543 	struct atalk_sock *at = at_sk(sk);
1544 	struct sockaddr_at *usat = (struct sockaddr_at *)msg->msg_name;
1545 	int flags = msg->msg_flags;
1546 	int loopback = 0;
1547 	struct sockaddr_at local_satalk, gsat;
1548 	struct sk_buff *skb;
1549 	struct net_device *dev;
1550 	struct ddpehdr *ddp;
1551 	int size;
1552 	struct atalk_route *rt;
1553 	int err;
1554 
1555 	if (flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT))
1556 		return -EINVAL;
1557 
1558 	if (len > DDP_MAXSZ)
1559 		return -EMSGSIZE;
1560 
1561 	if (usat) {
1562 		if (sock_flag(sk, SOCK_ZAPPED))
1563 			if (atalk_autobind(sk) < 0)
1564 				return -EBUSY;
1565 
1566 		if (msg->msg_namelen < sizeof(*usat) ||
1567 		    usat->sat_family != AF_APPLETALK)
1568 			return -EINVAL;
1569 
1570 		/* netatalk doesn't implement this check */
1571 		if (usat->sat_addr.s_node == ATADDR_BCAST &&
1572 		    !sock_flag(sk, SOCK_BROADCAST)) {
1573 			printk(KERN_INFO "SO_BROADCAST: Fix your netatalk as "
1574 					 "it will break before 2.2\n");
1575 #if 0
1576 			return -EPERM;
1577 #endif
1578 		}
1579 	} else {
1580 		if (sk->sk_state != TCP_ESTABLISHED)
1581 			return -ENOTCONN;
1582 		usat = &local_satalk;
1583 		usat->sat_family      = AF_APPLETALK;
1584 		usat->sat_port	      = at->dest_port;
1585 		usat->sat_addr.s_node = at->dest_node;
1586 		usat->sat_addr.s_net  = at->dest_net;
1587 	}
1588 
1589 	/* Build a packet */
1590 	SOCK_DEBUG(sk, "SK %p: Got address.\n", sk);
1591 
1592 	/* For headers */
1593 	size = sizeof(struct ddpehdr) + len + ddp_dl->header_length;
1594 
1595 	if (usat->sat_addr.s_net || usat->sat_addr.s_node == ATADDR_ANYNODE) {
1596 		rt = atrtr_find(&usat->sat_addr);
1597 		dev = rt->dev;
1598 	} else {
1599 		struct atalk_addr at_hint;
1600 
1601 		at_hint.s_node = 0;
1602 		at_hint.s_net  = at->src_net;
1603 
1604 		rt = atrtr_find(&at_hint);
1605 		dev = rt->dev;
1606 	}
1607 	if (!rt)
1608 		return -ENETUNREACH;
1609 
1610 	dev = rt->dev;
1611 
1612 	SOCK_DEBUG(sk, "SK %p: Size needed %d, device %s\n",
1613 			sk, size, dev->name);
1614 
1615 	size += dev->hard_header_len;
1616 	skb = sock_alloc_send_skb(sk, size, (flags & MSG_DONTWAIT), &err);
1617 	if (!skb)
1618 		return err;
1619 
1620 	skb->sk = sk;
1621 	skb_reserve(skb, ddp_dl->header_length);
1622 	skb_reserve(skb, dev->hard_header_len);
1623 	skb->dev = dev;
1624 
1625 	SOCK_DEBUG(sk, "SK %p: Begin build.\n", sk);
1626 
1627 	ddp = (struct ddpehdr *)skb_put(skb, sizeof(struct ddpehdr));
1628 	ddp->deh_pad  = 0;
1629 	ddp->deh_hops = 0;
1630 	ddp->deh_len  = len + sizeof(*ddp);
1631 	/*
1632 	 * Fix up the length field [Ok this is horrible but otherwise
1633 	 * I end up with unions of bit fields and messy bit field order
1634 	 * compiler/endian dependencies..
1635 	 */
1636 	*((__u16 *)ddp) = ntohs(*((__u16 *)ddp));
1637 
1638 	ddp->deh_dnet  = usat->sat_addr.s_net;
1639 	ddp->deh_snet  = at->src_net;
1640 	ddp->deh_dnode = usat->sat_addr.s_node;
1641 	ddp->deh_snode = at->src_node;
1642 	ddp->deh_dport = usat->sat_port;
1643 	ddp->deh_sport = at->src_port;
1644 
1645 	SOCK_DEBUG(sk, "SK %p: Copy user data (%Zd bytes).\n", sk, len);
1646 
1647 	err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1648 	if (err) {
1649 		kfree_skb(skb);
1650 		return -EFAULT;
1651 	}
1652 
1653 	if (sk->sk_no_check == 1)
1654 		ddp->deh_sum = 0;
1655 	else
1656 		ddp->deh_sum = atalk_checksum(skb, len + sizeof(*ddp));
1657 
1658 	/*
1659 	 * Loopback broadcast packets to non gateway targets (ie routes
1660 	 * to group we are in)
1661 	 */
1662 	if (ddp->deh_dnode == ATADDR_BCAST &&
1663 	    !(rt->flags & RTF_GATEWAY) && !(dev->flags & IFF_LOOPBACK)) {
1664 		struct sk_buff *skb2 = skb_copy(skb, GFP_KERNEL);
1665 
1666 		if (skb2) {
1667 			loopback = 1;
1668 			SOCK_DEBUG(sk, "SK %p: send out(copy).\n", sk);
1669 			if (aarp_send_ddp(dev, skb2,
1670 					  &usat->sat_addr, NULL) == -1)
1671 				kfree_skb(skb2);
1672 				/* else queued/sent above in the aarp queue */
1673 		}
1674 	}
1675 
1676 	if (dev->flags & IFF_LOOPBACK || loopback) {
1677 		SOCK_DEBUG(sk, "SK %p: Loop back.\n", sk);
1678 		/* loop back */
1679 		skb_orphan(skb);
1680 		if (ddp->deh_dnode == ATADDR_BCAST) {
1681 			struct atalk_addr at_lo;
1682 
1683 			at_lo.s_node = 0;
1684 			at_lo.s_net  = 0;
1685 
1686 			rt = atrtr_find(&at_lo);
1687 			if (!rt) {
1688 				kfree_skb(skb);
1689 				return -ENETUNREACH;
1690 			}
1691 			dev = rt->dev;
1692 			skb->dev = dev;
1693 		}
1694 		ddp_dl->request(ddp_dl, skb, dev->dev_addr);
1695 	} else {
1696 		SOCK_DEBUG(sk, "SK %p: send out.\n", sk);
1697 		if (rt->flags & RTF_GATEWAY) {
1698 		    gsat.sat_addr = rt->gateway;
1699 		    usat = &gsat;
1700 		}
1701 
1702 		if (aarp_send_ddp(dev, skb, &usat->sat_addr, NULL) == -1)
1703 			kfree_skb(skb);
1704 		/* else queued/sent above in the aarp queue */
1705 	}
1706 	SOCK_DEBUG(sk, "SK %p: Done write (%Zd).\n", sk, len);
1707 
1708 	return len;
1709 }
1710 
1711 static int atalk_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
1712 			 size_t size, int flags)
1713 {
1714 	struct sock *sk = sock->sk;
1715 	struct sockaddr_at *sat = (struct sockaddr_at *)msg->msg_name;
1716 	struct ddpehdr *ddp;
1717 	int copied = 0;
1718 	int err = 0;
1719         struct ddpebits ddphv;
1720 	struct sk_buff *skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
1721 						flags & MSG_DONTWAIT, &err);
1722 	if (!skb)
1723 		return err;
1724 
1725 	/* FIXME: use skb->cb to be able to use shared skbs */
1726 	ddp = ddp_hdr(skb);
1727 	*((__u16 *)&ddphv) = ntohs(*((__u16 *)ddp));
1728 
1729 	if (sk->sk_type == SOCK_RAW) {
1730 		copied = ddphv.deh_len;
1731 		if (copied > size) {
1732 			copied = size;
1733 			msg->msg_flags |= MSG_TRUNC;
1734 		}
1735 
1736 		err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1737 	} else {
1738 		copied = ddphv.deh_len - sizeof(*ddp);
1739 		if (copied > size) {
1740 			copied = size;
1741 			msg->msg_flags |= MSG_TRUNC;
1742 		}
1743 		err = skb_copy_datagram_iovec(skb, sizeof(*ddp),
1744 					      msg->msg_iov, copied);
1745 	}
1746 
1747 	if (!err) {
1748 		if (sat) {
1749 			sat->sat_family      = AF_APPLETALK;
1750 			sat->sat_port        = ddp->deh_sport;
1751 			sat->sat_addr.s_node = ddp->deh_snode;
1752 			sat->sat_addr.s_net  = ddp->deh_snet;
1753 		}
1754 		msg->msg_namelen = sizeof(*sat);
1755 	}
1756 
1757 	skb_free_datagram(sk, skb);	/* Free the datagram. */
1758 	return err ? : copied;
1759 }
1760 
1761 
1762 /*
1763  * AppleTalk ioctl calls.
1764  */
1765 static int atalk_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1766 {
1767 	int rc = -ENOIOCTLCMD;
1768 	struct sock *sk = sock->sk;
1769 	void __user *argp = (void __user *)arg;
1770 
1771 	switch (cmd) {
1772 		/* Protocol layer */
1773 		case TIOCOUTQ: {
1774 			long amount = sk->sk_sndbuf -
1775 				      atomic_read(&sk->sk_wmem_alloc);
1776 
1777 			if (amount < 0)
1778 				amount = 0;
1779 			rc = put_user(amount, (int __user *)argp);
1780 			break;
1781 		}
1782 		case TIOCINQ: {
1783 			/*
1784 			 * These two are safe on a single CPU system as only
1785 			 * user tasks fiddle here
1786 			 */
1787 			struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1788 			long amount = 0;
1789 
1790 			if (skb)
1791 				amount = skb->len - sizeof(struct ddpehdr);
1792 			rc = put_user(amount, (int __user *)argp);
1793 			break;
1794 		}
1795 		case SIOCGSTAMP:
1796 			rc = sock_get_timestamp(sk, argp);
1797 			break;
1798 		/* Routing */
1799 		case SIOCADDRT:
1800 		case SIOCDELRT:
1801 			rc = -EPERM;
1802 			if (capable(CAP_NET_ADMIN))
1803 				rc = atrtr_ioctl(cmd, argp);
1804 			break;
1805 		/* Interface */
1806 		case SIOCGIFADDR:
1807 		case SIOCSIFADDR:
1808 		case SIOCGIFBRDADDR:
1809 		case SIOCATALKDIFADDR:
1810 		case SIOCDIFADDR:
1811 		case SIOCSARP:		/* proxy AARP */
1812 		case SIOCDARP:		/* proxy AARP */
1813 			rtnl_lock();
1814 			rc = atif_ioctl(cmd, argp);
1815 			rtnl_unlock();
1816 			break;
1817 	}
1818 
1819 	return rc;
1820 }
1821 
1822 
1823 #ifdef CONFIG_COMPAT
1824 static int atalk_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1825 {
1826 	/*
1827 	 * All Appletalk ioctls except SIOCATALKDIFADDR are standard.  And
1828 	 * SIOCATALKDIFADDR is handled by upper layer as well, so there is
1829 	 * nothing to do.  Eventually SIOCATALKDIFADDR should be moved
1830 	 * here so there is no generic SIOCPROTOPRIVATE translation in the
1831 	 * system.
1832 	 */
1833 	return -ENOIOCTLCMD;
1834 }
1835 #endif
1836 
1837 
1838 static struct net_proto_family atalk_family_ops = {
1839 	.family		= PF_APPLETALK,
1840 	.create		= atalk_create,
1841 	.owner		= THIS_MODULE,
1842 };
1843 
1844 static const struct proto_ops SOCKOPS_WRAPPED(atalk_dgram_ops) = {
1845 	.family		= PF_APPLETALK,
1846 	.owner		= THIS_MODULE,
1847 	.release	= atalk_release,
1848 	.bind		= atalk_bind,
1849 	.connect	= atalk_connect,
1850 	.socketpair	= sock_no_socketpair,
1851 	.accept		= sock_no_accept,
1852 	.getname	= atalk_getname,
1853 	.poll		= datagram_poll,
1854 	.ioctl		= atalk_ioctl,
1855 #ifdef CONFIG_COMPAT
1856 	.compat_ioctl	= atalk_compat_ioctl,
1857 #endif
1858 	.listen		= sock_no_listen,
1859 	.shutdown	= sock_no_shutdown,
1860 	.setsockopt	= sock_no_setsockopt,
1861 	.getsockopt	= sock_no_getsockopt,
1862 	.sendmsg	= atalk_sendmsg,
1863 	.recvmsg	= atalk_recvmsg,
1864 	.mmap		= sock_no_mmap,
1865 	.sendpage	= sock_no_sendpage,
1866 };
1867 
1868 #include <linux/smp_lock.h>
1869 SOCKOPS_WRAP(atalk_dgram, PF_APPLETALK);
1870 
1871 static struct notifier_block ddp_notifier = {
1872 	.notifier_call	= ddp_device_event,
1873 };
1874 
1875 static struct packet_type ltalk_packet_type = {
1876 	.type		= __constant_htons(ETH_P_LOCALTALK),
1877 	.func		= ltalk_rcv,
1878 };
1879 
1880 static struct packet_type ppptalk_packet_type = {
1881 	.type		= __constant_htons(ETH_P_PPPTALK),
1882 	.func		= atalk_rcv,
1883 };
1884 
1885 static unsigned char ddp_snap_id[] = { 0x08, 0x00, 0x07, 0x80, 0x9B };
1886 
1887 /* Export symbols for use by drivers when AppleTalk is a module */
1888 EXPORT_SYMBOL(aarp_send_ddp);
1889 EXPORT_SYMBOL(atrtr_get_dev);
1890 EXPORT_SYMBOL(atalk_find_dev_addr);
1891 
1892 static char atalk_err_snap[] __initdata =
1893 	KERN_CRIT "Unable to register DDP with SNAP.\n";
1894 
1895 /* Called by proto.c on kernel start up */
1896 static int __init atalk_init(void)
1897 {
1898 	int rc = proto_register(&ddp_proto, 0);
1899 
1900 	if (rc != 0)
1901 		goto out;
1902 
1903 	(void)sock_register(&atalk_family_ops);
1904 	ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv);
1905 	if (!ddp_dl)
1906 		printk(atalk_err_snap);
1907 
1908 	dev_add_pack(&ltalk_packet_type);
1909 	dev_add_pack(&ppptalk_packet_type);
1910 
1911 	register_netdevice_notifier(&ddp_notifier);
1912 	aarp_proto_init();
1913 	atalk_proc_init();
1914 	atalk_register_sysctl();
1915 out:
1916 	return rc;
1917 }
1918 module_init(atalk_init);
1919 
1920 /*
1921  * No explicit module reference count manipulation is needed in the
1922  * protocol. Socket layer sets module reference count for us
1923  * and interfaces reference counting is done
1924  * by the network device layer.
1925  *
1926  * Ergo, before the AppleTalk module can be removed, all AppleTalk
1927  * sockets be closed from user space.
1928  */
1929 static void __exit atalk_exit(void)
1930 {
1931 #ifdef CONFIG_SYSCTL
1932 	atalk_unregister_sysctl();
1933 #endif /* CONFIG_SYSCTL */
1934 	atalk_proc_exit();
1935 	aarp_cleanup_module();	/* General aarp clean-up. */
1936 	unregister_netdevice_notifier(&ddp_notifier);
1937 	dev_remove_pack(&ltalk_packet_type);
1938 	dev_remove_pack(&ppptalk_packet_type);
1939 	unregister_snap_client(ddp_dl);
1940 	sock_unregister(PF_APPLETALK);
1941 	proto_unregister(&ddp_proto);
1942 }
1943 module_exit(atalk_exit);
1944 
1945 MODULE_LICENSE("GPL");
1946 MODULE_AUTHOR("Alan Cox <Alan.Cox@linux.org>");
1947 MODULE_DESCRIPTION("AppleTalk 0.20\n");
1948 MODULE_ALIAS_NETPROTO(PF_APPLETALK);
1949