xref: /linux/net/appletalk/ddp.c (revision 95db3b255fde4e830e5f8cc011eb404023f669d4)
1 /*
2  *	DDP:	An implementation of the AppleTalk DDP protocol for
3  *		Ethernet 'ELAP'.
4  *
5  *		Alan Cox  <alan@lxorguk.ukuu.org.uk>
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/capability.h>
55 #include <linux/module.h>
56 #include <linux/if_arp.h>
57 #include <linux/termios.h>	/* For TIOCOUTQ/INQ */
58 #include <linux/compat.h>
59 #include <linux/slab.h>
60 #include <net/datalink.h>
61 #include <net/psnap.h>
62 #include <net/sock.h>
63 #include <net/tcp_states.h>
64 #include <net/route.h>
65 #include <linux/atalk.h>
66 #include <linux/highmem.h>
67 
68 struct datalink_proto *ddp_dl, *aarp_dl;
69 static const struct proto_ops atalk_dgram_ops;
70 
71 /**************************************************************************\
72 *                                                                          *
73 * Handlers for the socket list.                                            *
74 *                                                                          *
75 \**************************************************************************/
76 
77 HLIST_HEAD(atalk_sockets);
78 DEFINE_RWLOCK(atalk_sockets_lock);
79 
80 static inline void __atalk_insert_socket(struct sock *sk)
81 {
82 	sk_add_node(sk, &atalk_sockets);
83 }
84 
85 static inline void atalk_remove_socket(struct sock *sk)
86 {
87 	write_lock_bh(&atalk_sockets_lock);
88 	sk_del_node_init(sk);
89 	write_unlock_bh(&atalk_sockets_lock);
90 }
91 
92 static struct sock *atalk_search_socket(struct sockaddr_at *to,
93 					struct atalk_iface *atif)
94 {
95 	struct sock *s;
96 
97 	read_lock_bh(&atalk_sockets_lock);
98 	sk_for_each(s, &atalk_sockets) {
99 		struct atalk_sock *at = at_sk(s);
100 
101 		if (to->sat_port != at->src_port)
102 			continue;
103 
104 		if (to->sat_addr.s_net == ATADDR_ANYNET &&
105 		    to->sat_addr.s_node == ATADDR_BCAST)
106 			goto found;
107 
108 		if (to->sat_addr.s_net == at->src_net &&
109 		    (to->sat_addr.s_node == at->src_node ||
110 		     to->sat_addr.s_node == ATADDR_BCAST ||
111 		     to->sat_addr.s_node == ATADDR_ANYNODE))
112 			goto found;
113 
114 		/* XXXX.0 -- we got a request for this router. make sure
115 		 * that the node is appropriately set. */
116 		if (to->sat_addr.s_node == ATADDR_ANYNODE &&
117 		    to->sat_addr.s_net != ATADDR_ANYNET &&
118 		    atif->address.s_node == at->src_node) {
119 			to->sat_addr.s_node = atif->address.s_node;
120 			goto found;
121 		}
122 	}
123 	s = NULL;
124 found:
125 	read_unlock_bh(&atalk_sockets_lock);
126 	return s;
127 }
128 
129 /**
130  * atalk_find_or_insert_socket - Try to find a socket matching ADDR
131  * @sk: socket to insert in the list if it is not there already
132  * @sat: address to search for
133  *
134  * Try to find a socket matching ADDR in the socket list, if found then return
135  * it. If not, insert SK into the socket list.
136  *
137  * This entire operation must execute atomically.
138  */
139 static struct sock *atalk_find_or_insert_socket(struct sock *sk,
140 						struct sockaddr_at *sat)
141 {
142 	struct sock *s;
143 	struct atalk_sock *at;
144 
145 	write_lock_bh(&atalk_sockets_lock);
146 	sk_for_each(s, &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 (sk_has_allocations(sk)) {
166 		sk->sk_timer.expires = jiffies + SOCK_DESTROY_TIME;
167 		add_timer(&sk->sk_timer);
168 	} else
169 		sock_put(sk);
170 }
171 
172 static inline void atalk_destroy_socket(struct sock *sk)
173 {
174 	atalk_remove_socket(sk);
175 	skb_queue_purge(&sk->sk_receive_queue);
176 
177 	if (sk_has_allocations(sk)) {
178 		setup_timer(&sk->sk_timer, atalk_destroy_timer,
179 				(unsigned long)sk);
180 		sk->sk_timer.expires	= jiffies + SOCK_DESTROY_TIME;
181 		add_timer(&sk->sk_timer);
182 	} else
183 		sock_put(sk);
184 }
185 
186 /**************************************************************************\
187 *                                                                          *
188 * Routing tables for the AppleTalk socket layer.                           *
189 *                                                                          *
190 \**************************************************************************/
191 
192 /* Anti-deadlock ordering is atalk_routes_lock --> iface_lock -DaveM */
193 struct atalk_route *atalk_routes;
194 DEFINE_RWLOCK(atalk_routes_lock);
195 
196 struct atalk_iface *atalk_interfaces;
197 DEFINE_RWLOCK(atalk_interfaces_lock);
198 
199 /* For probing devices or in a routerless network */
200 struct atalk_route atrtr_default;
201 
202 /* AppleTalk interface control */
203 /*
204  * Drop a device. Doesn't drop any of its routes - that is the caller's
205  * problem. Called when we down the interface or delete the address.
206  */
207 static void atif_drop_device(struct net_device *dev)
208 {
209 	struct atalk_iface **iface = &atalk_interfaces;
210 	struct atalk_iface *tmp;
211 
212 	write_lock_bh(&atalk_interfaces_lock);
213 	while ((tmp = *iface) != NULL) {
214 		if (tmp->dev == dev) {
215 			*iface = tmp->next;
216 			dev_put(dev);
217 			kfree(tmp);
218 			dev->atalk_ptr = NULL;
219 		} else
220 			iface = &tmp->next;
221 	}
222 	write_unlock_bh(&atalk_interfaces_lock);
223 }
224 
225 static struct atalk_iface *atif_add_device(struct net_device *dev,
226 					   struct atalk_addr *sa)
227 {
228 	struct atalk_iface *iface = kzalloc(sizeof(*iface), GFP_KERNEL);
229 
230 	if (!iface)
231 		goto out;
232 
233 	dev_hold(dev);
234 	iface->dev = dev;
235 	dev->atalk_ptr = iface;
236 	iface->address = *sa;
237 	iface->status = 0;
238 
239 	write_lock_bh(&atalk_interfaces_lock);
240 	iface->next = atalk_interfaces;
241 	atalk_interfaces = iface;
242 	write_unlock_bh(&atalk_interfaces_lock);
243 out:
244 	return iface;
245 }
246 
247 /* Perform phase 2 AARP probing on our tentative address */
248 static int atif_probe_device(struct atalk_iface *atif)
249 {
250 	int netrange = ntohs(atif->nets.nr_lastnet) -
251 			ntohs(atif->nets.nr_firstnet) + 1;
252 	int probe_net = ntohs(atif->address.s_net);
253 	int probe_node = atif->address.s_node;
254 	int netct, nodect;
255 
256 	/* Offset the network we start probing with */
257 	if (probe_net == ATADDR_ANYNET) {
258 		probe_net = ntohs(atif->nets.nr_firstnet);
259 		if (netrange)
260 			probe_net += jiffies % netrange;
261 	}
262 	if (probe_node == ATADDR_ANYNODE)
263 		probe_node = jiffies & 0xFF;
264 
265 	/* Scan the networks */
266 	atif->status |= ATIF_PROBE;
267 	for (netct = 0; netct <= netrange; netct++) {
268 		/* Sweep the available nodes from a given start */
269 		atif->address.s_net = htons(probe_net);
270 		for (nodect = 0; nodect < 256; nodect++) {
271 			atif->address.s_node = (nodect + probe_node) & 0xFF;
272 			if (atif->address.s_node > 0 &&
273 			    atif->address.s_node < 254) {
274 				/* Probe a proposed address */
275 				aarp_probe_network(atif);
276 
277 				if (!(atif->status & ATIF_PROBE_FAIL)) {
278 					atif->status &= ~ATIF_PROBE;
279 					return 0;
280 				}
281 			}
282 			atif->status &= ~ATIF_PROBE_FAIL;
283 		}
284 		probe_net++;
285 		if (probe_net > ntohs(atif->nets.nr_lastnet))
286 			probe_net = ntohs(atif->nets.nr_firstnet);
287 	}
288 	atif->status &= ~ATIF_PROBE;
289 
290 	return -EADDRINUSE;	/* Network is full... */
291 }
292 
293 
294 /* Perform AARP probing for a proxy address */
295 static int atif_proxy_probe_device(struct atalk_iface *atif,
296 				   struct atalk_addr *proxy_addr)
297 {
298 	int netrange = ntohs(atif->nets.nr_lastnet) -
299 			ntohs(atif->nets.nr_firstnet) + 1;
300 	/* we probe the interface's network */
301 	int probe_net = ntohs(atif->address.s_net);
302 	int probe_node = ATADDR_ANYNODE;	    /* we'll take anything */
303 	int netct, nodect;
304 
305 	/* Offset the network we start probing with */
306 	if (probe_net == ATADDR_ANYNET) {
307 		probe_net = ntohs(atif->nets.nr_firstnet);
308 		if (netrange)
309 			probe_net += jiffies % netrange;
310 	}
311 
312 	if (probe_node == ATADDR_ANYNODE)
313 		probe_node = jiffies & 0xFF;
314 
315 	/* Scan the networks */
316 	for (netct = 0; netct <= netrange; netct++) {
317 		/* Sweep the available nodes from a given start */
318 		proxy_addr->s_net = htons(probe_net);
319 		for (nodect = 0; nodect < 256; nodect++) {
320 			proxy_addr->s_node = (nodect + probe_node) & 0xFF;
321 			if (proxy_addr->s_node > 0 &&
322 			    proxy_addr->s_node < 254) {
323 				/* Tell AARP to probe a proposed address */
324 				int ret = aarp_proxy_probe_network(atif,
325 								    proxy_addr);
326 
327 				if (ret != -EADDRINUSE)
328 					return ret;
329 			}
330 		}
331 		probe_net++;
332 		if (probe_net > ntohs(atif->nets.nr_lastnet))
333 			probe_net = ntohs(atif->nets.nr_firstnet);
334 	}
335 
336 	return -EADDRINUSE;	/* Network is full... */
337 }
338 
339 
340 struct atalk_addr *atalk_find_dev_addr(struct net_device *dev)
341 {
342 	struct atalk_iface *iface = dev->atalk_ptr;
343 	return iface ? &iface->address : NULL;
344 }
345 
346 static struct atalk_addr *atalk_find_primary(void)
347 {
348 	struct atalk_iface *fiface = NULL;
349 	struct atalk_addr *retval;
350 	struct atalk_iface *iface;
351 
352 	/*
353 	 * Return a point-to-point interface only if
354 	 * there is no non-ptp interface available.
355 	 */
356 	read_lock_bh(&atalk_interfaces_lock);
357 	for (iface = atalk_interfaces; iface; iface = iface->next) {
358 		if (!fiface && !(iface->dev->flags & IFF_LOOPBACK))
359 			fiface = iface;
360 		if (!(iface->dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
361 			retval = &iface->address;
362 			goto out;
363 		}
364 	}
365 
366 	if (fiface)
367 		retval = &fiface->address;
368 	else if (atalk_interfaces)
369 		retval = &atalk_interfaces->address;
370 	else
371 		retval = NULL;
372 out:
373 	read_unlock_bh(&atalk_interfaces_lock);
374 	return retval;
375 }
376 
377 /*
378  * Find a match for 'any network' - ie any of our interfaces with that
379  * node number will do just nicely.
380  */
381 static struct atalk_iface *atalk_find_anynet(int node, struct net_device *dev)
382 {
383 	struct atalk_iface *iface = dev->atalk_ptr;
384 
385 	if (!iface || iface->status & ATIF_PROBE)
386 		goto out_err;
387 
388 	if (node != ATADDR_BCAST &&
389 	    iface->address.s_node != node &&
390 	    node != ATADDR_ANYNODE)
391 		goto out_err;
392 out:
393 	return iface;
394 out_err:
395 	iface = NULL;
396 	goto out;
397 }
398 
399 /* Find a match for a specific network:node pair */
400 static struct atalk_iface *atalk_find_interface(__be16 net, int node)
401 {
402 	struct atalk_iface *iface;
403 
404 	read_lock_bh(&atalk_interfaces_lock);
405 	for (iface = atalk_interfaces; iface; iface = iface->next) {
406 		if ((node == ATADDR_BCAST ||
407 		     node == ATADDR_ANYNODE ||
408 		     iface->address.s_node == node) &&
409 		    iface->address.s_net == net &&
410 		    !(iface->status & ATIF_PROBE))
411 			break;
412 
413 		/* XXXX.0 -- net.0 returns the iface associated with net */
414 		if (node == ATADDR_ANYNODE && net != ATADDR_ANYNET &&
415 		    ntohs(iface->nets.nr_firstnet) <= ntohs(net) &&
416 		    ntohs(net) <= ntohs(iface->nets.nr_lastnet))
417 			break;
418 	}
419 	read_unlock_bh(&atalk_interfaces_lock);
420 	return iface;
421 }
422 
423 
424 /*
425  * Find a route for an AppleTalk packet. This ought to get cached in
426  * the socket (later on...). We know about host routes and the fact
427  * that a route must be direct to broadcast.
428  */
429 static struct atalk_route *atrtr_find(struct atalk_addr *target)
430 {
431 	/*
432 	 * we must search through all routes unless we find a
433 	 * host route, because some host routes might overlap
434 	 * network routes
435 	 */
436 	struct atalk_route *net_route = NULL;
437 	struct atalk_route *r;
438 
439 	read_lock_bh(&atalk_routes_lock);
440 	for (r = atalk_routes; r; r = r->next) {
441 		if (!(r->flags & RTF_UP))
442 			continue;
443 
444 		if (r->target.s_net == target->s_net) {
445 			if (r->flags & RTF_HOST) {
446 				/*
447 				 * if this host route is for the target,
448 				 * the we're done
449 				 */
450 				if (r->target.s_node == target->s_node)
451 					goto out;
452 			} else
453 				/*
454 				 * this route will work if there isn't a
455 				 * direct host route, so cache it
456 				 */
457 				net_route = r;
458 		}
459 	}
460 
461 	/*
462 	 * if we found a network route but not a direct host
463 	 * route, then return it
464 	 */
465 	if (net_route)
466 		r = net_route;
467 	else if (atrtr_default.dev)
468 		r = &atrtr_default;
469 	else /* No route can be found */
470 		r = NULL;
471 out:
472 	read_unlock_bh(&atalk_routes_lock);
473 	return r;
474 }
475 
476 
477 /*
478  * Given an AppleTalk network, find the device to use. This can be
479  * a simple lookup.
480  */
481 struct net_device *atrtr_get_dev(struct atalk_addr *sa)
482 {
483 	struct atalk_route *atr = atrtr_find(sa);
484 	return atr ? atr->dev : NULL;
485 }
486 
487 /* Set up a default router */
488 static void atrtr_set_default(struct net_device *dev)
489 {
490 	atrtr_default.dev	     = dev;
491 	atrtr_default.flags	     = RTF_UP;
492 	atrtr_default.gateway.s_net  = htons(0);
493 	atrtr_default.gateway.s_node = 0;
494 }
495 
496 /*
497  * Add a router. Basically make sure it looks valid and stuff the
498  * entry in the list. While it uses netranges we always set them to one
499  * entry to work like netatalk.
500  */
501 static int atrtr_create(struct rtentry *r, struct net_device *devhint)
502 {
503 	struct sockaddr_at *ta = (struct sockaddr_at *)&r->rt_dst;
504 	struct sockaddr_at *ga = (struct sockaddr_at *)&r->rt_gateway;
505 	struct atalk_route *rt;
506 	struct atalk_iface *iface, *riface;
507 	int retval = -EINVAL;
508 
509 	/*
510 	 * Fixme: Raise/Lower a routing change semaphore for these
511 	 * operations.
512 	 */
513 
514 	/* Validate the request */
515 	if (ta->sat_family != AF_APPLETALK ||
516 	    (!devhint && ga->sat_family != AF_APPLETALK))
517 		goto out;
518 
519 	/* Now walk the routing table and make our decisions */
520 	write_lock_bh(&atalk_routes_lock);
521 	for (rt = atalk_routes; rt; rt = rt->next) {
522 		if (r->rt_flags != rt->flags)
523 			continue;
524 
525 		if (ta->sat_addr.s_net == rt->target.s_net) {
526 			if (!(rt->flags & RTF_HOST))
527 				break;
528 			if (ta->sat_addr.s_node == rt->target.s_node)
529 				break;
530 		}
531 	}
532 
533 	if (!devhint) {
534 		riface = NULL;
535 
536 		read_lock_bh(&atalk_interfaces_lock);
537 		for (iface = atalk_interfaces; iface; iface = iface->next) {
538 			if (!riface &&
539 			    ntohs(ga->sat_addr.s_net) >=
540 					ntohs(iface->nets.nr_firstnet) &&
541 			    ntohs(ga->sat_addr.s_net) <=
542 					ntohs(iface->nets.nr_lastnet))
543 				riface = iface;
544 
545 			if (ga->sat_addr.s_net == iface->address.s_net &&
546 			    ga->sat_addr.s_node == iface->address.s_node)
547 				riface = iface;
548 		}
549 		read_unlock_bh(&atalk_interfaces_lock);
550 
551 		retval = -ENETUNREACH;
552 		if (!riface)
553 			goto out_unlock;
554 
555 		devhint = riface->dev;
556 	}
557 
558 	if (!rt) {
559 		rt = kzalloc(sizeof(*rt), GFP_ATOMIC);
560 
561 		retval = -ENOBUFS;
562 		if (!rt)
563 			goto out_unlock;
564 
565 		rt->next = atalk_routes;
566 		atalk_routes = rt;
567 	}
568 
569 	/* Fill in the routing entry */
570 	rt->target  = ta->sat_addr;
571 	dev_hold(devhint);
572 	rt->dev     = devhint;
573 	rt->flags   = r->rt_flags;
574 	rt->gateway = ga->sat_addr;
575 
576 	retval = 0;
577 out_unlock:
578 	write_unlock_bh(&atalk_routes_lock);
579 out:
580 	return retval;
581 }
582 
583 /* Delete a route. Find it and discard it */
584 static int atrtr_delete(struct atalk_addr *addr)
585 {
586 	struct atalk_route **r = &atalk_routes;
587 	int retval = 0;
588 	struct atalk_route *tmp;
589 
590 	write_lock_bh(&atalk_routes_lock);
591 	while ((tmp = *r) != NULL) {
592 		if (tmp->target.s_net == addr->s_net &&
593 		    (!(tmp->flags&RTF_GATEWAY) ||
594 		     tmp->target.s_node == addr->s_node)) {
595 			*r = tmp->next;
596 			dev_put(tmp->dev);
597 			kfree(tmp);
598 			goto out;
599 		}
600 		r = &tmp->next;
601 	}
602 	retval = -ENOENT;
603 out:
604 	write_unlock_bh(&atalk_routes_lock);
605 	return retval;
606 }
607 
608 /*
609  * Called when a device is downed. Just throw away any routes
610  * via it.
611  */
612 static void atrtr_device_down(struct net_device *dev)
613 {
614 	struct atalk_route **r = &atalk_routes;
615 	struct atalk_route *tmp;
616 
617 	write_lock_bh(&atalk_routes_lock);
618 	while ((tmp = *r) != NULL) {
619 		if (tmp->dev == dev) {
620 			*r = tmp->next;
621 			dev_put(dev);
622 			kfree(tmp);
623 		} else
624 			r = &tmp->next;
625 	}
626 	write_unlock_bh(&atalk_routes_lock);
627 
628 	if (atrtr_default.dev == dev)
629 		atrtr_set_default(NULL);
630 }
631 
632 /* Actually down the interface */
633 static inline void atalk_dev_down(struct net_device *dev)
634 {
635 	atrtr_device_down(dev);	/* Remove all routes for the device */
636 	aarp_device_down(dev);	/* Remove AARP entries for the device */
637 	atif_drop_device(dev);	/* Remove the device */
638 }
639 
640 /*
641  * A device event has occurred. Watch for devices going down and
642  * delete our use of them (iface and route).
643  */
644 static int ddp_device_event(struct notifier_block *this, unsigned long event,
645 			    void *ptr)
646 {
647 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
648 
649 	if (!net_eq(dev_net(dev), &init_net))
650 		return NOTIFY_DONE;
651 
652 	if (event == NETDEV_DOWN)
653 		/* Discard any use of this */
654 		atalk_dev_down(dev);
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(&init_net, 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_global(dev, aarp_mcast);
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 		/*
817 		 * for now, we only support proxy AARP on ELAP;
818 		 * we should be able to do it for LocalTalk, too.
819 		 */
820 		if (dev->type != ARPHRD_ETHER)
821 			return -EPROTONOSUPPORT;
822 
823 		/*
824 		 * atif points to the current interface on this network;
825 		 * we aren't concerned about its current status (at
826 		 * least for now), but it has all the settings about
827 		 * the network we're going to probe. Consequently, it
828 		 * must exist.
829 		 */
830 		if (!atif)
831 			return -EADDRNOTAVAIL;
832 
833 		nr = (struct atalk_netrange *)&(atif->nets);
834 		/*
835 		 * Phase 1 is fine on Localtalk but we don't do
836 		 * Ethertalk phase 1. Anyone wanting to add it go ahead.
837 		 */
838 		if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
839 			return -EPROTONOSUPPORT;
840 
841 		if (sa->sat_addr.s_node == ATADDR_BCAST ||
842 		    sa->sat_addr.s_node == 254)
843 			return -EINVAL;
844 
845 		/*
846 		 * Check if the chosen address is used. If so we
847 		 * error and ATCP will try another.
848 		 */
849 		if (atif_proxy_probe_device(atif, &(sa->sat_addr)) < 0)
850 			return -EADDRINUSE;
851 
852 		/*
853 		 * We now have an address on the local network, and
854 		 * the AARP code will defend it for us until we take it
855 		 * down. We don't set up any routes right now, because
856 		 * ATCP will install them manually via SIOCADDRT.
857 		 */
858 		break;
859 
860 	case SIOCDARP:
861 		if (!capable(CAP_NET_ADMIN))
862 			return -EPERM;
863 		if (sa->sat_family != AF_APPLETALK)
864 			return -EINVAL;
865 		if (!atif)
866 			return -EADDRNOTAVAIL;
867 
868 		/* give to aarp module to remove proxy entry */
869 		aarp_proxy_remove(atif->dev, &(sa->sat_addr));
870 		return 0;
871 	}
872 
873 	return copy_to_user(arg, &atreq, sizeof(atreq)) ? -EFAULT : 0;
874 }
875 
876 /* Routing ioctl() calls */
877 static int atrtr_ioctl(unsigned int cmd, void __user *arg)
878 {
879 	struct rtentry rt;
880 
881 	if (copy_from_user(&rt, arg, sizeof(rt)))
882 		return -EFAULT;
883 
884 	switch (cmd) {
885 	case SIOCDELRT:
886 		if (rt.rt_dst.sa_family != AF_APPLETALK)
887 			return -EINVAL;
888 		return atrtr_delete(&((struct sockaddr_at *)
889 				      &rt.rt_dst)->sat_addr);
890 
891 	case SIOCADDRT: {
892 		struct net_device *dev = NULL;
893 		if (rt.rt_dev) {
894 			char name[IFNAMSIZ];
895 			if (copy_from_user(name, rt.rt_dev, IFNAMSIZ-1))
896 				return -EFAULT;
897 			name[IFNAMSIZ-1] = '\0';
898 			dev = __dev_get_by_name(&init_net, name);
899 			if (!dev)
900 				return -ENODEV;
901 		}
902 		return atrtr_create(&rt, dev);
903 	}
904 	}
905 	return -EINVAL;
906 }
907 
908 /**************************************************************************\
909 *                                                                          *
910 * Handling for system calls applied via the various interfaces to an       *
911 * AppleTalk socket object.                                                 *
912 *                                                                          *
913 \**************************************************************************/
914 
915 /*
916  * Checksum: This is 'optional'. It's quite likely also a good
917  * candidate for assembler hackery 8)
918  */
919 static unsigned long atalk_sum_partial(const unsigned char *data,
920 				       int len, unsigned long sum)
921 {
922 	/* This ought to be unwrapped neatly. I'll trust gcc for now */
923 	while (len--) {
924 		sum += *data++;
925 		sum = rol16(sum, 1);
926 	}
927 	return sum;
928 }
929 
930 /*  Checksum skb data --  similar to skb_checksum  */
931 static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
932 				   int len, unsigned long sum)
933 {
934 	int start = skb_headlen(skb);
935 	struct sk_buff *frag_iter;
936 	int i, copy;
937 
938 	/* checksum stuff in header space */
939 	if ((copy = start - offset) > 0) {
940 		if (copy > len)
941 			copy = len;
942 		sum = atalk_sum_partial(skb->data + offset, copy, sum);
943 		if ((len -= copy) == 0)
944 			return sum;
945 
946 		offset += copy;
947 	}
948 
949 	/* checksum stuff in frags */
950 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
951 		int end;
952 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
953 		WARN_ON(start > offset + len);
954 
955 		end = start + skb_frag_size(frag);
956 		if ((copy = end - offset) > 0) {
957 			u8 *vaddr;
958 
959 			if (copy > len)
960 				copy = len;
961 			vaddr = kmap_atomic(skb_frag_page(frag));
962 			sum = atalk_sum_partial(vaddr + frag->page_offset +
963 						  offset - start, copy, sum);
964 			kunmap_atomic(vaddr);
965 
966 			if (!(len -= copy))
967 				return sum;
968 			offset += copy;
969 		}
970 		start = end;
971 	}
972 
973 	skb_walk_frags(skb, frag_iter) {
974 		int end;
975 
976 		WARN_ON(start > offset + len);
977 
978 		end = start + frag_iter->len;
979 		if ((copy = end - offset) > 0) {
980 			if (copy > len)
981 				copy = len;
982 			sum = atalk_sum_skb(frag_iter, offset - start,
983 					    copy, sum);
984 			if ((len -= copy) == 0)
985 				return sum;
986 			offset += copy;
987 		}
988 		start = end;
989 	}
990 
991 	BUG_ON(len > 0);
992 
993 	return sum;
994 }
995 
996 static __be16 atalk_checksum(const struct sk_buff *skb, int len)
997 {
998 	unsigned long sum;
999 
1000 	/* skip header 4 bytes */
1001 	sum = atalk_sum_skb(skb, 4, len-4, 0);
1002 
1003 	/* Use 0xFFFF for 0. 0 itself means none */
1004 	return sum ? htons((unsigned short)sum) : htons(0xFFFF);
1005 }
1006 
1007 static struct proto ddp_proto = {
1008 	.name	  = "DDP",
1009 	.owner	  = THIS_MODULE,
1010 	.obj_size = sizeof(struct atalk_sock),
1011 };
1012 
1013 /*
1014  * Create a socket. Initialise the socket, blank the addresses
1015  * set the state.
1016  */
1017 static int atalk_create(struct net *net, struct socket *sock, int protocol,
1018 			int kern)
1019 {
1020 	struct sock *sk;
1021 	int rc = -ESOCKTNOSUPPORT;
1022 
1023 	if (!net_eq(net, &init_net))
1024 		return -EAFNOSUPPORT;
1025 
1026 	/*
1027 	 * We permit SOCK_DGRAM and RAW is an extension. It is trivial to do
1028 	 * and gives you the full ELAP frame. Should be handy for CAP 8)
1029 	 */
1030 	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
1031 		goto out;
1032 	rc = -ENOMEM;
1033 	sk = sk_alloc(net, PF_APPLETALK, GFP_KERNEL, &ddp_proto, kern);
1034 	if (!sk)
1035 		goto out;
1036 	rc = 0;
1037 	sock->ops = &atalk_dgram_ops;
1038 	sock_init_data(sock, sk);
1039 
1040 	/* Checksums on by default */
1041 	sock_set_flag(sk, SOCK_ZAPPED);
1042 out:
1043 	return rc;
1044 }
1045 
1046 /* Free a socket. No work needed */
1047 static int atalk_release(struct socket *sock)
1048 {
1049 	struct sock *sk = sock->sk;
1050 
1051 	if (sk) {
1052 		sock_hold(sk);
1053 		lock_sock(sk);
1054 
1055 		sock_orphan(sk);
1056 		sock->sk = NULL;
1057 		atalk_destroy_socket(sk);
1058 
1059 		release_sock(sk);
1060 		sock_put(sk);
1061 	}
1062 	return 0;
1063 }
1064 
1065 /**
1066  * atalk_pick_and_bind_port - Pick a source port when one is not given
1067  * @sk: socket to insert into the tables
1068  * @sat: address to search for
1069  *
1070  * Pick a source port when one is not given. If we can find a suitable free
1071  * one, we insert the socket into the tables using it.
1072  *
1073  * This whole operation must be atomic.
1074  */
1075 static int atalk_pick_and_bind_port(struct sock *sk, struct sockaddr_at *sat)
1076 {
1077 	int retval;
1078 
1079 	write_lock_bh(&atalk_sockets_lock);
1080 
1081 	for (sat->sat_port = ATPORT_RESERVED;
1082 	     sat->sat_port < ATPORT_LAST;
1083 	     sat->sat_port++) {
1084 		struct sock *s;
1085 
1086 		sk_for_each(s, &atalk_sockets) {
1087 			struct atalk_sock *at = at_sk(s);
1088 
1089 			if (at->src_net == sat->sat_addr.s_net &&
1090 			    at->src_node == sat->sat_addr.s_node &&
1091 			    at->src_port == sat->sat_port)
1092 				goto try_next_port;
1093 		}
1094 
1095 		/* Wheee, it's free, assign and insert. */
1096 		__atalk_insert_socket(sk);
1097 		at_sk(sk)->src_port = sat->sat_port;
1098 		retval = 0;
1099 		goto out;
1100 
1101 try_next_port:;
1102 	}
1103 
1104 	retval = -EBUSY;
1105 out:
1106 	write_unlock_bh(&atalk_sockets_lock);
1107 	return retval;
1108 }
1109 
1110 static int atalk_autobind(struct sock *sk)
1111 {
1112 	struct atalk_sock *at = at_sk(sk);
1113 	struct sockaddr_at sat;
1114 	struct atalk_addr *ap = atalk_find_primary();
1115 	int n = -EADDRNOTAVAIL;
1116 
1117 	if (!ap || ap->s_net == htons(ATADDR_ANYNET))
1118 		goto out;
1119 
1120 	at->src_net  = sat.sat_addr.s_net  = ap->s_net;
1121 	at->src_node = sat.sat_addr.s_node = ap->s_node;
1122 
1123 	n = atalk_pick_and_bind_port(sk, &sat);
1124 	if (!n)
1125 		sock_reset_flag(sk, SOCK_ZAPPED);
1126 out:
1127 	return n;
1128 }
1129 
1130 /* Set the address 'our end' of the connection */
1131 static int atalk_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1132 {
1133 	struct sockaddr_at *addr = (struct sockaddr_at *)uaddr;
1134 	struct sock *sk = sock->sk;
1135 	struct atalk_sock *at = at_sk(sk);
1136 	int err;
1137 
1138 	if (!sock_flag(sk, SOCK_ZAPPED) ||
1139 	    addr_len != sizeof(struct sockaddr_at))
1140 		return -EINVAL;
1141 
1142 	if (addr->sat_family != AF_APPLETALK)
1143 		return -EAFNOSUPPORT;
1144 
1145 	lock_sock(sk);
1146 	if (addr->sat_addr.s_net == htons(ATADDR_ANYNET)) {
1147 		struct atalk_addr *ap = atalk_find_primary();
1148 
1149 		err = -EADDRNOTAVAIL;
1150 		if (!ap)
1151 			goto out;
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 		err = -EADDRNOTAVAIL;
1157 		if (!atalk_find_interface(addr->sat_addr.s_net,
1158 					  addr->sat_addr.s_node))
1159 			goto out;
1160 
1161 		at->src_net  = addr->sat_addr.s_net;
1162 		at->src_node = addr->sat_addr.s_node;
1163 	}
1164 
1165 	if (addr->sat_port == ATADDR_ANYPORT) {
1166 		err = atalk_pick_and_bind_port(sk, addr);
1167 
1168 		if (err < 0)
1169 			goto out;
1170 	} else {
1171 		at->src_port = addr->sat_port;
1172 
1173 		err = -EADDRINUSE;
1174 		if (atalk_find_or_insert_socket(sk, addr))
1175 			goto out;
1176 	}
1177 
1178 	sock_reset_flag(sk, SOCK_ZAPPED);
1179 	err = 0;
1180 out:
1181 	release_sock(sk);
1182 	return err;
1183 }
1184 
1185 /* Set the address we talk to */
1186 static int atalk_connect(struct socket *sock, struct sockaddr *uaddr,
1187 			 int addr_len, int flags)
1188 {
1189 	struct sock *sk = sock->sk;
1190 	struct atalk_sock *at = at_sk(sk);
1191 	struct sockaddr_at *addr;
1192 	int err;
1193 
1194 	sk->sk_state   = TCP_CLOSE;
1195 	sock->state = SS_UNCONNECTED;
1196 
1197 	if (addr_len != sizeof(*addr))
1198 		return -EINVAL;
1199 
1200 	addr = (struct sockaddr_at *)uaddr;
1201 
1202 	if (addr->sat_family != AF_APPLETALK)
1203 		return -EAFNOSUPPORT;
1204 
1205 	if (addr->sat_addr.s_node == ATADDR_BCAST &&
1206 	    !sock_flag(sk, SOCK_BROADCAST)) {
1207 #if 1
1208 		pr_warn("atalk_connect: %s is broken and did not set SO_BROADCAST.\n",
1209 			current->comm);
1210 #else
1211 		return -EACCES;
1212 #endif
1213 	}
1214 
1215 	lock_sock(sk);
1216 	err = -EBUSY;
1217 	if (sock_flag(sk, SOCK_ZAPPED))
1218 		if (atalk_autobind(sk) < 0)
1219 			goto out;
1220 
1221 	err = -ENETUNREACH;
1222 	if (!atrtr_get_dev(&addr->sat_addr))
1223 		goto out;
1224 
1225 	at->dest_port = addr->sat_port;
1226 	at->dest_net  = addr->sat_addr.s_net;
1227 	at->dest_node = addr->sat_addr.s_node;
1228 
1229 	sock->state  = SS_CONNECTED;
1230 	sk->sk_state = TCP_ESTABLISHED;
1231 	err = 0;
1232 out:
1233 	release_sock(sk);
1234 	return err;
1235 }
1236 
1237 /*
1238  * Find the name of an AppleTalk socket. Just copy the right
1239  * fields into the sockaddr.
1240  */
1241 static int atalk_getname(struct socket *sock, struct sockaddr *uaddr,
1242 			 int *uaddr_len, int peer)
1243 {
1244 	struct sockaddr_at sat;
1245 	struct sock *sk = sock->sk;
1246 	struct atalk_sock *at = at_sk(sk);
1247 	int err;
1248 
1249 	lock_sock(sk);
1250 	err = -ENOBUFS;
1251 	if (sock_flag(sk, SOCK_ZAPPED))
1252 		if (atalk_autobind(sk) < 0)
1253 			goto out;
1254 
1255 	*uaddr_len = sizeof(struct sockaddr_at);
1256 	memset(&sat, 0, sizeof(sat));
1257 
1258 	if (peer) {
1259 		err = -ENOTCONN;
1260 		if (sk->sk_state != TCP_ESTABLISHED)
1261 			goto out;
1262 
1263 		sat.sat_addr.s_net  = at->dest_net;
1264 		sat.sat_addr.s_node = at->dest_node;
1265 		sat.sat_port	    = at->dest_port;
1266 	} else {
1267 		sat.sat_addr.s_net  = at->src_net;
1268 		sat.sat_addr.s_node = at->src_node;
1269 		sat.sat_port	    = at->src_port;
1270 	}
1271 
1272 	err = 0;
1273 	sat.sat_family = AF_APPLETALK;
1274 	memcpy(uaddr, &sat, sizeof(sat));
1275 
1276 out:
1277 	release_sock(sk);
1278 	return err;
1279 }
1280 
1281 #if defined(CONFIG_IPDDP) || defined(CONFIG_IPDDP_MODULE)
1282 static __inline__ int is_ip_over_ddp(struct sk_buff *skb)
1283 {
1284 	return skb->data[12] == 22;
1285 }
1286 
1287 static int handle_ip_over_ddp(struct sk_buff *skb)
1288 {
1289 	struct net_device *dev = __dev_get_by_name(&init_net, "ipddp0");
1290 	struct net_device_stats *stats;
1291 
1292 	/* This needs to be able to handle ipddp"N" devices */
1293 	if (!dev) {
1294 		kfree_skb(skb);
1295 		return NET_RX_DROP;
1296 	}
1297 
1298 	skb->protocol = htons(ETH_P_IP);
1299 	skb_pull(skb, 13);
1300 	skb->dev   = dev;
1301 	skb_reset_transport_header(skb);
1302 
1303 	stats = netdev_priv(dev);
1304 	stats->rx_packets++;
1305 	stats->rx_bytes += skb->len + 13;
1306 	return netif_rx(skb);  /* Send the SKB up to a higher place. */
1307 }
1308 #else
1309 /* make it easy for gcc to optimize this test out, i.e. kill the code */
1310 #define is_ip_over_ddp(skb) 0
1311 #define handle_ip_over_ddp(skb) 0
1312 #endif
1313 
1314 static int atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
1315 			      struct ddpehdr *ddp, __u16 len_hops, int origlen)
1316 {
1317 	struct atalk_route *rt;
1318 	struct atalk_addr ta;
1319 
1320 	/*
1321 	 * Don't route multicast, etc., packets, or packets sent to "this
1322 	 * network"
1323 	 */
1324 	if (skb->pkt_type != PACKET_HOST || !ddp->deh_dnet) {
1325 		/*
1326 		 * FIXME:
1327 		 *
1328 		 * Can it ever happen that a packet is from a PPP iface and
1329 		 * needs to be broadcast onto the default network?
1330 		 */
1331 		if (dev->type == ARPHRD_PPP)
1332 			printk(KERN_DEBUG "AppleTalk: didn't forward broadcast "
1333 					  "packet received from PPP iface\n");
1334 		goto free_it;
1335 	}
1336 
1337 	ta.s_net  = ddp->deh_dnet;
1338 	ta.s_node = ddp->deh_dnode;
1339 
1340 	/* Route the packet */
1341 	rt = atrtr_find(&ta);
1342 	/* increment hops count */
1343 	len_hops += 1 << 10;
1344 	if (!rt || !(len_hops & (15 << 10)))
1345 		goto free_it;
1346 
1347 	/* FIXME: use skb->cb to be able to use shared skbs */
1348 
1349 	/*
1350 	 * Route goes through another gateway, so set the target to the
1351 	 * gateway instead.
1352 	 */
1353 
1354 	if (rt->flags & RTF_GATEWAY) {
1355 		ta.s_net  = rt->gateway.s_net;
1356 		ta.s_node = rt->gateway.s_node;
1357 	}
1358 
1359 	/* Fix up skb->len field */
1360 	skb_trim(skb, min_t(unsigned int, origlen,
1361 			    (rt->dev->hard_header_len +
1362 			     ddp_dl->header_length + (len_hops & 1023))));
1363 
1364 	/* FIXME: use skb->cb to be able to use shared skbs */
1365 	ddp->deh_len_hops = htons(len_hops);
1366 
1367 	/*
1368 	 * Send the buffer onwards
1369 	 *
1370 	 * Now we must always be careful. If it's come from LocalTalk to
1371 	 * EtherTalk it might not fit
1372 	 *
1373 	 * Order matters here: If a packet has to be copied to make a new
1374 	 * headroom (rare hopefully) then it won't need unsharing.
1375 	 *
1376 	 * Note. ddp-> becomes invalid at the realloc.
1377 	 */
1378 	if (skb_headroom(skb) < 22) {
1379 		/* 22 bytes - 12 ether, 2 len, 3 802.2 5 snap */
1380 		struct sk_buff *nskb = skb_realloc_headroom(skb, 32);
1381 		kfree_skb(skb);
1382 		skb = nskb;
1383 	} else
1384 		skb = skb_unshare(skb, GFP_ATOMIC);
1385 
1386 	/*
1387 	 * If the buffer didn't vanish into the lack of space bitbucket we can
1388 	 * send it.
1389 	 */
1390 	if (skb == NULL)
1391 		goto drop;
1392 
1393 	if (aarp_send_ddp(rt->dev, skb, &ta, NULL) == NET_XMIT_DROP)
1394 		return NET_RX_DROP;
1395 	return NET_RX_SUCCESS;
1396 free_it:
1397 	kfree_skb(skb);
1398 drop:
1399 	return NET_RX_DROP;
1400 }
1401 
1402 /**
1403  *	atalk_rcv - Receive a packet (in skb) from device dev
1404  *	@skb - packet received
1405  *	@dev - network device where the packet comes from
1406  *	@pt - packet type
1407  *
1408  *	Receive a packet (in skb) from device dev. This has come from the SNAP
1409  *	decoder, and on entry skb->transport_header is the DDP header, skb->len
1410  *	is the DDP header, skb->len is the DDP length. The physical headers
1411  *	have been extracted. PPP should probably pass frames marked as for this
1412  *	layer.  [ie ARPHRD_ETHERTALK]
1413  */
1414 static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
1415 		     struct packet_type *pt, struct net_device *orig_dev)
1416 {
1417 	struct ddpehdr *ddp;
1418 	struct sock *sock;
1419 	struct atalk_iface *atif;
1420 	struct sockaddr_at tosat;
1421 	int origlen;
1422 	__u16 len_hops;
1423 
1424 	if (!net_eq(dev_net(dev), &init_net))
1425 		goto drop;
1426 
1427 	/* Don't mangle buffer if shared */
1428 	if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
1429 		goto out;
1430 
1431 	/* Size check and make sure header is contiguous */
1432 	if (!pskb_may_pull(skb, sizeof(*ddp)))
1433 		goto drop;
1434 
1435 	ddp = ddp_hdr(skb);
1436 
1437 	len_hops = ntohs(ddp->deh_len_hops);
1438 
1439 	/* Trim buffer in case of stray trailing data */
1440 	origlen = skb->len;
1441 	skb_trim(skb, min_t(unsigned int, skb->len, len_hops & 1023));
1442 
1443 	/*
1444 	 * Size check to see if ddp->deh_len was crap
1445 	 * (Otherwise we'll detonate most spectacularly
1446 	 * in the middle of atalk_checksum() or recvmsg()).
1447 	 */
1448 	if (skb->len < sizeof(*ddp) || skb->len < (len_hops & 1023)) {
1449 		pr_debug("AppleTalk: dropping corrupted frame (deh_len=%u, "
1450 			 "skb->len=%u)\n", len_hops & 1023, skb->len);
1451 		goto drop;
1452 	}
1453 
1454 	/*
1455 	 * Any checksums. Note we don't do htons() on this == is assumed to be
1456 	 * valid for net byte orders all over the networking code...
1457 	 */
1458 	if (ddp->deh_sum &&
1459 	    atalk_checksum(skb, len_hops & 1023) != ddp->deh_sum)
1460 		/* Not a valid AppleTalk frame - dustbin time */
1461 		goto drop;
1462 
1463 	/* Check the packet is aimed at us */
1464 	if (!ddp->deh_dnet)	/* Net 0 is 'this network' */
1465 		atif = atalk_find_anynet(ddp->deh_dnode, dev);
1466 	else
1467 		atif = atalk_find_interface(ddp->deh_dnet, ddp->deh_dnode);
1468 
1469 	if (!atif) {
1470 		/* Not ours, so we route the packet via the correct
1471 		 * AppleTalk iface
1472 		 */
1473 		return atalk_route_packet(skb, dev, ddp, len_hops, origlen);
1474 	}
1475 
1476 	/* if IP over DDP is not selected this code will be optimized out */
1477 	if (is_ip_over_ddp(skb))
1478 		return handle_ip_over_ddp(skb);
1479 	/*
1480 	 * Which socket - atalk_search_socket() looks for a *full match*
1481 	 * of the <net, node, port> tuple.
1482 	 */
1483 	tosat.sat_addr.s_net  = ddp->deh_dnet;
1484 	tosat.sat_addr.s_node = ddp->deh_dnode;
1485 	tosat.sat_port	      = ddp->deh_dport;
1486 
1487 	sock = atalk_search_socket(&tosat, atif);
1488 	if (!sock) /* But not one of our sockets */
1489 		goto drop;
1490 
1491 	/* Queue packet (standard) */
1492 	if (sock_queue_rcv_skb(sock, skb) < 0)
1493 		goto drop;
1494 
1495 	return NET_RX_SUCCESS;
1496 
1497 drop:
1498 	kfree_skb(skb);
1499 out:
1500 	return NET_RX_DROP;
1501 
1502 }
1503 
1504 /*
1505  * Receive a LocalTalk frame. We make some demands on the caller here.
1506  * Caller must provide enough headroom on the packet to pull the short
1507  * header and append a long one.
1508  */
1509 static int ltalk_rcv(struct sk_buff *skb, struct net_device *dev,
1510 		     struct packet_type *pt, struct net_device *orig_dev)
1511 {
1512 	if (!net_eq(dev_net(dev), &init_net))
1513 		goto freeit;
1514 
1515 	/* Expand any short form frames */
1516 	if (skb_mac_header(skb)[2] == 1) {
1517 		struct ddpehdr *ddp;
1518 		/* Find our address */
1519 		struct atalk_addr *ap = atalk_find_dev_addr(dev);
1520 
1521 		if (!ap || skb->len < sizeof(__be16) || skb->len > 1023)
1522 			goto freeit;
1523 
1524 		/* Don't mangle buffer if shared */
1525 		if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
1526 			return 0;
1527 
1528 		/*
1529 		 * The push leaves us with a ddephdr not an shdr, and
1530 		 * handily the port bytes in the right place preset.
1531 		 */
1532 		ddp = (struct ddpehdr *) skb_push(skb, sizeof(*ddp) - 4);
1533 
1534 		/* Now fill in the long header */
1535 
1536 		/*
1537 		 * These two first. The mac overlays the new source/dest
1538 		 * network information so we MUST copy these before
1539 		 * we write the network numbers !
1540 		 */
1541 
1542 		ddp->deh_dnode = skb_mac_header(skb)[0];     /* From physical header */
1543 		ddp->deh_snode = skb_mac_header(skb)[1];     /* From physical header */
1544 
1545 		ddp->deh_dnet  = ap->s_net;	/* Network number */
1546 		ddp->deh_snet  = ap->s_net;
1547 		ddp->deh_sum   = 0;		/* No checksum */
1548 		/*
1549 		 * Not sure about this bit...
1550 		 */
1551 		/* Non routable, so force a drop if we slip up later */
1552 		ddp->deh_len_hops = htons(skb->len + (DDP_MAXHOPS << 10));
1553 	}
1554 	skb_reset_transport_header(skb);
1555 
1556 	return atalk_rcv(skb, dev, pt, orig_dev);
1557 freeit:
1558 	kfree_skb(skb);
1559 	return 0;
1560 }
1561 
1562 static int atalk_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1563 {
1564 	struct sock *sk = sock->sk;
1565 	struct atalk_sock *at = at_sk(sk);
1566 	DECLARE_SOCKADDR(struct sockaddr_at *, usat, msg->msg_name);
1567 	int flags = msg->msg_flags;
1568 	int loopback = 0;
1569 	struct sockaddr_at local_satalk, gsat;
1570 	struct sk_buff *skb;
1571 	struct net_device *dev;
1572 	struct ddpehdr *ddp;
1573 	int size;
1574 	struct atalk_route *rt;
1575 	int err;
1576 
1577 	if (flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT))
1578 		return -EINVAL;
1579 
1580 	if (len > DDP_MAXSZ)
1581 		return -EMSGSIZE;
1582 
1583 	lock_sock(sk);
1584 	if (usat) {
1585 		err = -EBUSY;
1586 		if (sock_flag(sk, SOCK_ZAPPED))
1587 			if (atalk_autobind(sk) < 0)
1588 				goto out;
1589 
1590 		err = -EINVAL;
1591 		if (msg->msg_namelen < sizeof(*usat) ||
1592 		    usat->sat_family != AF_APPLETALK)
1593 			goto out;
1594 
1595 		err = -EPERM;
1596 		/* netatalk didn't implement this check */
1597 		if (usat->sat_addr.s_node == ATADDR_BCAST &&
1598 		    !sock_flag(sk, SOCK_BROADCAST)) {
1599 			goto out;
1600 		}
1601 	} else {
1602 		err = -ENOTCONN;
1603 		if (sk->sk_state != TCP_ESTABLISHED)
1604 			goto out;
1605 		usat = &local_satalk;
1606 		usat->sat_family      = AF_APPLETALK;
1607 		usat->sat_port	      = at->dest_port;
1608 		usat->sat_addr.s_node = at->dest_node;
1609 		usat->sat_addr.s_net  = at->dest_net;
1610 	}
1611 
1612 	/* Build a packet */
1613 	SOCK_DEBUG(sk, "SK %p: Got address.\n", sk);
1614 
1615 	/* For headers */
1616 	size = sizeof(struct ddpehdr) + len + ddp_dl->header_length;
1617 
1618 	if (usat->sat_addr.s_net || usat->sat_addr.s_node == ATADDR_ANYNODE) {
1619 		rt = atrtr_find(&usat->sat_addr);
1620 	} else {
1621 		struct atalk_addr at_hint;
1622 
1623 		at_hint.s_node = 0;
1624 		at_hint.s_net  = at->src_net;
1625 
1626 		rt = atrtr_find(&at_hint);
1627 	}
1628 	err = -ENETUNREACH;
1629 	if (!rt)
1630 		goto out;
1631 
1632 	dev = rt->dev;
1633 
1634 	SOCK_DEBUG(sk, "SK %p: Size needed %d, device %s\n",
1635 			sk, size, dev->name);
1636 
1637 	size += dev->hard_header_len;
1638 	release_sock(sk);
1639 	skb = sock_alloc_send_skb(sk, size, (flags & MSG_DONTWAIT), &err);
1640 	lock_sock(sk);
1641 	if (!skb)
1642 		goto out;
1643 
1644 	skb_reserve(skb, ddp_dl->header_length);
1645 	skb_reserve(skb, dev->hard_header_len);
1646 	skb->dev = dev;
1647 
1648 	SOCK_DEBUG(sk, "SK %p: Begin build.\n", sk);
1649 
1650 	ddp = (struct ddpehdr *)skb_put(skb, sizeof(struct ddpehdr));
1651 	ddp->deh_len_hops  = htons(len + sizeof(*ddp));
1652 	ddp->deh_dnet  = usat->sat_addr.s_net;
1653 	ddp->deh_snet  = at->src_net;
1654 	ddp->deh_dnode = usat->sat_addr.s_node;
1655 	ddp->deh_snode = at->src_node;
1656 	ddp->deh_dport = usat->sat_port;
1657 	ddp->deh_sport = at->src_port;
1658 
1659 	SOCK_DEBUG(sk, "SK %p: Copy user data (%Zd bytes).\n", sk, len);
1660 
1661 	err = memcpy_from_msg(skb_put(skb, len), msg, len);
1662 	if (err) {
1663 		kfree_skb(skb);
1664 		err = -EFAULT;
1665 		goto out;
1666 	}
1667 
1668 	if (sk->sk_no_check_tx)
1669 		ddp->deh_sum = 0;
1670 	else
1671 		ddp->deh_sum = atalk_checksum(skb, len + sizeof(*ddp));
1672 
1673 	/*
1674 	 * Loopback broadcast packets to non gateway targets (ie routes
1675 	 * to group we are in)
1676 	 */
1677 	if (ddp->deh_dnode == ATADDR_BCAST &&
1678 	    !(rt->flags & RTF_GATEWAY) && !(dev->flags & IFF_LOOPBACK)) {
1679 		struct sk_buff *skb2 = skb_copy(skb, GFP_KERNEL);
1680 
1681 		if (skb2) {
1682 			loopback = 1;
1683 			SOCK_DEBUG(sk, "SK %p: send out(copy).\n", sk);
1684 			/*
1685 			 * If it fails it is queued/sent above in the aarp queue
1686 			 */
1687 			aarp_send_ddp(dev, skb2, &usat->sat_addr, NULL);
1688 		}
1689 	}
1690 
1691 	if (dev->flags & IFF_LOOPBACK || loopback) {
1692 		SOCK_DEBUG(sk, "SK %p: Loop back.\n", sk);
1693 		/* loop back */
1694 		skb_orphan(skb);
1695 		if (ddp->deh_dnode == ATADDR_BCAST) {
1696 			struct atalk_addr at_lo;
1697 
1698 			at_lo.s_node = 0;
1699 			at_lo.s_net  = 0;
1700 
1701 			rt = atrtr_find(&at_lo);
1702 			if (!rt) {
1703 				kfree_skb(skb);
1704 				err = -ENETUNREACH;
1705 				goto out;
1706 			}
1707 			dev = rt->dev;
1708 			skb->dev = dev;
1709 		}
1710 		ddp_dl->request(ddp_dl, skb, dev->dev_addr);
1711 	} else {
1712 		SOCK_DEBUG(sk, "SK %p: send out.\n", sk);
1713 		if (rt->flags & RTF_GATEWAY) {
1714 		    gsat.sat_addr = rt->gateway;
1715 		    usat = &gsat;
1716 		}
1717 
1718 		/*
1719 		 * If it fails it is queued/sent above in the aarp queue
1720 		 */
1721 		aarp_send_ddp(dev, skb, &usat->sat_addr, NULL);
1722 	}
1723 	SOCK_DEBUG(sk, "SK %p: Done write (%Zd).\n", sk, len);
1724 
1725 out:
1726 	release_sock(sk);
1727 	return err ? : len;
1728 }
1729 
1730 static int atalk_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1731 			 int flags)
1732 {
1733 	struct sock *sk = sock->sk;
1734 	struct ddpehdr *ddp;
1735 	int copied = 0;
1736 	int offset = 0;
1737 	int err = 0;
1738 	struct sk_buff *skb;
1739 
1740 	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
1741 						flags & MSG_DONTWAIT, &err);
1742 	lock_sock(sk);
1743 
1744 	if (!skb)
1745 		goto out;
1746 
1747 	/* FIXME: use skb->cb to be able to use shared skbs */
1748 	ddp = ddp_hdr(skb);
1749 	copied = ntohs(ddp->deh_len_hops) & 1023;
1750 
1751 	if (sk->sk_type != SOCK_RAW) {
1752 		offset = sizeof(*ddp);
1753 		copied -= offset;
1754 	}
1755 
1756 	if (copied > size) {
1757 		copied = size;
1758 		msg->msg_flags |= MSG_TRUNC;
1759 	}
1760 	err = skb_copy_datagram_msg(skb, offset, msg, copied);
1761 
1762 	if (!err && msg->msg_name) {
1763 		DECLARE_SOCKADDR(struct sockaddr_at *, sat, msg->msg_name);
1764 		sat->sat_family      = AF_APPLETALK;
1765 		sat->sat_port        = ddp->deh_sport;
1766 		sat->sat_addr.s_node = ddp->deh_snode;
1767 		sat->sat_addr.s_net  = ddp->deh_snet;
1768 		msg->msg_namelen     = sizeof(*sat);
1769 	}
1770 
1771 	skb_free_datagram(sk, skb);	/* Free the datagram. */
1772 
1773 out:
1774 	release_sock(sk);
1775 	return err ? : copied;
1776 }
1777 
1778 
1779 /*
1780  * AppleTalk ioctl calls.
1781  */
1782 static int atalk_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1783 {
1784 	int rc = -ENOIOCTLCMD;
1785 	struct sock *sk = sock->sk;
1786 	void __user *argp = (void __user *)arg;
1787 
1788 	switch (cmd) {
1789 	/* Protocol layer */
1790 	case TIOCOUTQ: {
1791 		long amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
1792 
1793 		if (amount < 0)
1794 			amount = 0;
1795 		rc = put_user(amount, (int __user *)argp);
1796 		break;
1797 	}
1798 	case TIOCINQ: {
1799 		/*
1800 		 * These two are safe on a single CPU system as only
1801 		 * user tasks fiddle here
1802 		 */
1803 		struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1804 		long amount = 0;
1805 
1806 		if (skb)
1807 			amount = skb->len - sizeof(struct ddpehdr);
1808 		rc = put_user(amount, (int __user *)argp);
1809 		break;
1810 	}
1811 	case SIOCGSTAMP:
1812 		rc = sock_get_timestamp(sk, argp);
1813 		break;
1814 	case SIOCGSTAMPNS:
1815 		rc = sock_get_timestampns(sk, argp);
1816 		break;
1817 	/* Routing */
1818 	case SIOCADDRT:
1819 	case SIOCDELRT:
1820 		rc = -EPERM;
1821 		if (capable(CAP_NET_ADMIN))
1822 			rc = atrtr_ioctl(cmd, argp);
1823 		break;
1824 	/* Interface */
1825 	case SIOCGIFADDR:
1826 	case SIOCSIFADDR:
1827 	case SIOCGIFBRDADDR:
1828 	case SIOCATALKDIFADDR:
1829 	case SIOCDIFADDR:
1830 	case SIOCSARP:		/* proxy AARP */
1831 	case SIOCDARP:		/* proxy AARP */
1832 		rtnl_lock();
1833 		rc = atif_ioctl(cmd, argp);
1834 		rtnl_unlock();
1835 		break;
1836 	}
1837 
1838 	return rc;
1839 }
1840 
1841 
1842 #ifdef CONFIG_COMPAT
1843 static int atalk_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1844 {
1845 	/*
1846 	 * SIOCATALKDIFADDR is a SIOCPROTOPRIVATE ioctl number, so we
1847 	 * cannot handle it in common code. The data we access if ifreq
1848 	 * here is compatible, so we can simply call the native
1849 	 * handler.
1850 	 */
1851 	if (cmd == SIOCATALKDIFADDR)
1852 		return atalk_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
1853 
1854 	return -ENOIOCTLCMD;
1855 }
1856 #endif
1857 
1858 
1859 static const struct net_proto_family atalk_family_ops = {
1860 	.family		= PF_APPLETALK,
1861 	.create		= atalk_create,
1862 	.owner		= THIS_MODULE,
1863 };
1864 
1865 static const struct proto_ops atalk_dgram_ops = {
1866 	.family		= PF_APPLETALK,
1867 	.owner		= THIS_MODULE,
1868 	.release	= atalk_release,
1869 	.bind		= atalk_bind,
1870 	.connect	= atalk_connect,
1871 	.socketpair	= sock_no_socketpair,
1872 	.accept		= sock_no_accept,
1873 	.getname	= atalk_getname,
1874 	.poll		= datagram_poll,
1875 	.ioctl		= atalk_ioctl,
1876 #ifdef CONFIG_COMPAT
1877 	.compat_ioctl	= atalk_compat_ioctl,
1878 #endif
1879 	.listen		= sock_no_listen,
1880 	.shutdown	= sock_no_shutdown,
1881 	.setsockopt	= sock_no_setsockopt,
1882 	.getsockopt	= sock_no_getsockopt,
1883 	.sendmsg	= atalk_sendmsg,
1884 	.recvmsg	= atalk_recvmsg,
1885 	.mmap		= sock_no_mmap,
1886 	.sendpage	= sock_no_sendpage,
1887 };
1888 
1889 static struct notifier_block ddp_notifier = {
1890 	.notifier_call	= ddp_device_event,
1891 };
1892 
1893 static struct packet_type ltalk_packet_type __read_mostly = {
1894 	.type		= cpu_to_be16(ETH_P_LOCALTALK),
1895 	.func		= ltalk_rcv,
1896 };
1897 
1898 static struct packet_type ppptalk_packet_type __read_mostly = {
1899 	.type		= cpu_to_be16(ETH_P_PPPTALK),
1900 	.func		= atalk_rcv,
1901 };
1902 
1903 static unsigned char ddp_snap_id[] = { 0x08, 0x00, 0x07, 0x80, 0x9B };
1904 
1905 /* Export symbols for use by drivers when AppleTalk is a module */
1906 EXPORT_SYMBOL(atrtr_get_dev);
1907 EXPORT_SYMBOL(atalk_find_dev_addr);
1908 
1909 static const char atalk_err_snap[] __initconst =
1910 	KERN_CRIT "Unable to register DDP with SNAP.\n";
1911 
1912 /* Called by proto.c on kernel start up */
1913 static int __init atalk_init(void)
1914 {
1915 	int rc = proto_register(&ddp_proto, 0);
1916 
1917 	if (rc != 0)
1918 		goto out;
1919 
1920 	(void)sock_register(&atalk_family_ops);
1921 	ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv);
1922 	if (!ddp_dl)
1923 		printk(atalk_err_snap);
1924 
1925 	dev_add_pack(&ltalk_packet_type);
1926 	dev_add_pack(&ppptalk_packet_type);
1927 
1928 	register_netdevice_notifier(&ddp_notifier);
1929 	aarp_proto_init();
1930 	atalk_proc_init();
1931 	atalk_register_sysctl();
1932 out:
1933 	return rc;
1934 }
1935 module_init(atalk_init);
1936 
1937 /*
1938  * No explicit module reference count manipulation is needed in the
1939  * protocol. Socket layer sets module reference count for us
1940  * and interfaces reference counting is done
1941  * by the network device layer.
1942  *
1943  * Ergo, before the AppleTalk module can be removed, all AppleTalk
1944  * sockets be closed from user space.
1945  */
1946 static void __exit atalk_exit(void)
1947 {
1948 #ifdef CONFIG_SYSCTL
1949 	atalk_unregister_sysctl();
1950 #endif /* CONFIG_SYSCTL */
1951 	atalk_proc_exit();
1952 	aarp_cleanup_module();	/* General aarp clean-up. */
1953 	unregister_netdevice_notifier(&ddp_notifier);
1954 	dev_remove_pack(&ltalk_packet_type);
1955 	dev_remove_pack(&ppptalk_packet_type);
1956 	unregister_snap_client(ddp_dl);
1957 	sock_unregister(PF_APPLETALK);
1958 	proto_unregister(&ddp_proto);
1959 }
1960 module_exit(atalk_exit);
1961 
1962 MODULE_LICENSE("GPL");
1963 MODULE_AUTHOR("Alan Cox <alan@lxorguk.ukuu.org.uk>");
1964 MODULE_DESCRIPTION("AppleTalk 0.20\n");
1965 MODULE_ALIAS_NETPROTO(PF_APPLETALK);
1966