xref: /openbmc/linux/net/appletalk/ddp.c (revision fd589a8f)
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/smp_lock.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 #include "../core/kmap_skb.h"
66 
67 struct datalink_proto *ddp_dl, *aarp_dl;
68 static const struct proto_ops atalk_dgram_ops;
69 
70 /**************************************************************************\
71 *                                                                          *
72 * Handlers for the socket list.                                            *
73 *                                                                          *
74 \**************************************************************************/
75 
76 HLIST_HEAD(atalk_sockets);
77 DEFINE_RWLOCK(atalk_sockets_lock);
78 
79 static inline void __atalk_insert_socket(struct sock *sk)
80 {
81 	sk_add_node(sk, &atalk_sockets);
82 }
83 
84 static inline void atalk_remove_socket(struct sock *sk)
85 {
86 	write_lock_bh(&atalk_sockets_lock);
87 	sk_del_node_init(sk);
88 	write_unlock_bh(&atalk_sockets_lock);
89 }
90 
91 static struct sock *atalk_search_socket(struct sockaddr_at *to,
92 					struct atalk_iface *atif)
93 {
94 	struct sock *s;
95 	struct hlist_node *node;
96 
97 	read_lock_bh(&atalk_sockets_lock);
98 	sk_for_each(s, node, &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 hlist_node *node;
144 	struct atalk_sock *at;
145 
146 	write_lock_bh(&atalk_sockets_lock);
147 	sk_for_each(s, node, &atalk_sockets) {
148 		at = at_sk(s);
149 
150 		if (at->src_net == sat->sat_addr.s_net &&
151 		    at->src_node == sat->sat_addr.s_node &&
152 		    at->src_port == sat->sat_port)
153 			goto found;
154 	}
155 	s = NULL;
156 	__atalk_insert_socket(sk); /* Wheee, it's free, assign and insert. */
157 found:
158 	write_unlock_bh(&atalk_sockets_lock);
159 	return s;
160 }
161 
162 static void atalk_destroy_timer(unsigned long data)
163 {
164 	struct sock *sk = (struct sock *)data;
165 
166 	if (sk_has_allocations(sk)) {
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 (sk_has_allocations(sk)) {
179 		setup_timer(&sk->sk_timer, atalk_destroy_timer,
180 				(unsigned long)sk);
181 		sk->sk_timer.expires	= jiffies + SOCK_DESTROY_TIME;
182 		add_timer(&sk->sk_timer);
183 	} else
184 		sock_put(sk);
185 }
186 
187 /**************************************************************************\
188 *                                                                          *
189 * Routing tables for the AppleTalk socket layer.                           *
190 *                                                                          *
191 \**************************************************************************/
192 
193 /* Anti-deadlock ordering is atalk_routes_lock --> iface_lock -DaveM */
194 struct atalk_route *atalk_routes;
195 DEFINE_RWLOCK(atalk_routes_lock);
196 
197 struct atalk_iface *atalk_interfaces;
198 DEFINE_RWLOCK(atalk_interfaces_lock);
199 
200 /* For probing devices or in a routerless network */
201 struct atalk_route atrtr_default;
202 
203 /* AppleTalk interface control */
204 /*
205  * Drop a device. Doesn't drop any of its routes - that is the caller's
206  * problem. Called when we down the interface or delete the address.
207  */
208 static void atif_drop_device(struct net_device *dev)
209 {
210 	struct atalk_iface **iface = &atalk_interfaces;
211 	struct atalk_iface *tmp;
212 
213 	write_lock_bh(&atalk_interfaces_lock);
214 	while ((tmp = *iface) != NULL) {
215 		if (tmp->dev == dev) {
216 			*iface = tmp->next;
217 			dev_put(dev);
218 			kfree(tmp);
219 			dev->atalk_ptr = NULL;
220 		} else
221 			iface = &tmp->next;
222 	}
223 	write_unlock_bh(&atalk_interfaces_lock);
224 }
225 
226 static struct atalk_iface *atif_add_device(struct net_device *dev,
227 					   struct atalk_addr *sa)
228 {
229 	struct atalk_iface *iface = kzalloc(sizeof(*iface), GFP_KERNEL);
230 
231 	if (!iface)
232 		goto out;
233 
234 	dev_hold(dev);
235 	iface->dev = dev;
236 	dev->atalk_ptr = iface;
237 	iface->address = *sa;
238 	iface->status = 0;
239 
240 	write_lock_bh(&atalk_interfaces_lock);
241 	iface->next = atalk_interfaces;
242 	atalk_interfaces = iface;
243 	write_unlock_bh(&atalk_interfaces_lock);
244 out:
245 	return iface;
246 }
247 
248 /* Perform phase 2 AARP probing on our tentative address */
249 static int atif_probe_device(struct atalk_iface *atif)
250 {
251 	int netrange = ntohs(atif->nets.nr_lastnet) -
252 			ntohs(atif->nets.nr_firstnet) + 1;
253 	int probe_net = ntohs(atif->address.s_net);
254 	int probe_node = atif->address.s_node;
255 	int netct, nodect;
256 
257 	/* Offset the network we start probing with */
258 	if (probe_net == ATADDR_ANYNET) {
259 		probe_net = ntohs(atif->nets.nr_firstnet);
260 		if (netrange)
261 			probe_net += jiffies % netrange;
262 	}
263 	if (probe_node == ATADDR_ANYNODE)
264 		probe_node = jiffies & 0xFF;
265 
266 	/* Scan the networks */
267 	atif->status |= ATIF_PROBE;
268 	for (netct = 0; netct <= netrange; netct++) {
269 		/* Sweep the available nodes from a given start */
270 		atif->address.s_net = htons(probe_net);
271 		for (nodect = 0; nodect < 256; nodect++) {
272 			atif->address.s_node = (nodect + probe_node) & 0xFF;
273 			if (atif->address.s_node > 0 &&
274 			    atif->address.s_node < 254) {
275 				/* Probe a proposed address */
276 				aarp_probe_network(atif);
277 
278 				if (!(atif->status & ATIF_PROBE_FAIL)) {
279 					atif->status &= ~ATIF_PROBE;
280 					return 0;
281 				}
282 			}
283 			atif->status &= ~ATIF_PROBE_FAIL;
284 		}
285 		probe_net++;
286 		if (probe_net > ntohs(atif->nets.nr_lastnet))
287 			probe_net = ntohs(atif->nets.nr_firstnet);
288 	}
289 	atif->status &= ~ATIF_PROBE;
290 
291 	return -EADDRINUSE;	/* Network is full... */
292 }
293 
294 
295 /* Perform AARP probing for a proxy address */
296 static int atif_proxy_probe_device(struct atalk_iface *atif,
297 				   struct atalk_addr* proxy_addr)
298 {
299 	int netrange = ntohs(atif->nets.nr_lastnet) -
300 			ntohs(atif->nets.nr_firstnet) + 1;
301 	/* we probe the interface's network */
302 	int probe_net = ntohs(atif->address.s_net);
303 	int probe_node = ATADDR_ANYNODE;	    /* we'll take anything */
304 	int netct, nodect;
305 
306 	/* Offset the network we start probing with */
307 	if (probe_net == ATADDR_ANYNET) {
308 		probe_net = ntohs(atif->nets.nr_firstnet);
309 		if (netrange)
310 			probe_net += jiffies % netrange;
311 	}
312 
313 	if (probe_node == ATADDR_ANYNODE)
314 		probe_node = jiffies & 0xFF;
315 
316 	/* Scan the networks */
317 	for (netct = 0; netct <= netrange; netct++) {
318 		/* Sweep the available nodes from a given start */
319 		proxy_addr->s_net = htons(probe_net);
320 		for (nodect = 0; nodect < 256; nodect++) {
321 			proxy_addr->s_node = (nodect + probe_node) & 0xFF;
322 			if (proxy_addr->s_node > 0 &&
323 			    proxy_addr->s_node < 254) {
324 				/* Tell AARP to probe a proposed address */
325 				int ret = aarp_proxy_probe_network(atif,
326 								    proxy_addr);
327 
328 				if (ret != -EADDRINUSE)
329 					return ret;
330 			}
331 		}
332 		probe_net++;
333 		if (probe_net > ntohs(atif->nets.nr_lastnet))
334 			probe_net = ntohs(atif->nets.nr_firstnet);
335 	}
336 
337 	return -EADDRINUSE;	/* Network is full... */
338 }
339 
340 
341 struct atalk_addr *atalk_find_dev_addr(struct net_device *dev)
342 {
343 	struct atalk_iface *iface = dev->atalk_ptr;
344 	return iface ? &iface->address : NULL;
345 }
346 
347 static struct atalk_addr *atalk_find_primary(void)
348 {
349 	struct atalk_iface *fiface = NULL;
350 	struct atalk_addr *retval;
351 	struct atalk_iface *iface;
352 
353 	/*
354 	 * Return a point-to-point interface only if
355 	 * there is no non-ptp interface available.
356 	 */
357 	read_lock_bh(&atalk_interfaces_lock);
358 	for (iface = atalk_interfaces; iface; iface = iface->next) {
359 		if (!fiface && !(iface->dev->flags & IFF_LOOPBACK))
360 			fiface = iface;
361 		if (!(iface->dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
362 			retval = &iface->address;
363 			goto out;
364 		}
365 	}
366 
367 	if (fiface)
368 		retval = &fiface->address;
369 	else if (atalk_interfaces)
370 		retval = &atalk_interfaces->address;
371 	else
372 		retval = NULL;
373 out:
374 	read_unlock_bh(&atalk_interfaces_lock);
375 	return retval;
376 }
377 
378 /*
379  * Find a match for 'any network' - ie any of our interfaces with that
380  * node number will do just nicely.
381  */
382 static struct atalk_iface *atalk_find_anynet(int node, struct net_device *dev)
383 {
384 	struct atalk_iface *iface = dev->atalk_ptr;
385 
386 	if (!iface || iface->status & ATIF_PROBE)
387 		goto out_err;
388 
389 	if (node != ATADDR_BCAST &&
390 	    iface->address.s_node != node &&
391 	    node != ATADDR_ANYNODE)
392 		goto out_err;
393 out:
394 	return iface;
395 out_err:
396 	iface = NULL;
397 	goto out;
398 }
399 
400 /* Find a match for a specific network:node pair */
401 static struct atalk_iface *atalk_find_interface(__be16 net, int node)
402 {
403 	struct atalk_iface *iface;
404 
405 	read_lock_bh(&atalk_interfaces_lock);
406 	for (iface = atalk_interfaces; iface; iface = iface->next) {
407 		if ((node == ATADDR_BCAST ||
408 		     node == ATADDR_ANYNODE ||
409 		     iface->address.s_node == node) &&
410 		    iface->address.s_net == net &&
411 		    !(iface->status & ATIF_PROBE))
412 			break;
413 
414 		/* XXXX.0 -- net.0 returns the iface associated with net */
415 		if (node == ATADDR_ANYNODE && net != ATADDR_ANYNET &&
416 		    ntohs(iface->nets.nr_firstnet) <= ntohs(net) &&
417 		    ntohs(net) <= ntohs(iface->nets.nr_lastnet))
418 			break;
419 	}
420 	read_unlock_bh(&atalk_interfaces_lock);
421 	return iface;
422 }
423 
424 
425 /*
426  * Find a route for an AppleTalk packet. This ought to get cached in
427  * the socket (later on...). We know about host routes and the fact
428  * that a route must be direct to broadcast.
429  */
430 static struct atalk_route *atrtr_find(struct atalk_addr *target)
431 {
432 	/*
433 	 * we must search through all routes unless we find a
434 	 * host route, because some host routes might overlap
435 	 * network routes
436 	 */
437 	struct atalk_route *net_route = NULL;
438 	struct atalk_route *r;
439 
440 	read_lock_bh(&atalk_routes_lock);
441 	for (r = atalk_routes; r; r = r->next) {
442 		if (!(r->flags & RTF_UP))
443 			continue;
444 
445 		if (r->target.s_net == target->s_net) {
446 			if (r->flags & RTF_HOST) {
447 				/*
448 				 * if this host route is for the target,
449 				 * the we're done
450 				 */
451 				if (r->target.s_node == target->s_node)
452 					goto out;
453 			} else
454 				/*
455 				 * this route will work if there isn't a
456 				 * direct host route, so cache it
457 				 */
458 				net_route = r;
459 		}
460 	}
461 
462 	/*
463 	 * if we found a network route but not a direct host
464 	 * route, then return it
465 	 */
466 	if (net_route)
467 		r = net_route;
468 	else if (atrtr_default.dev)
469 		r = &atrtr_default;
470 	else /* No route can be found */
471 		r = NULL;
472 out:
473 	read_unlock_bh(&atalk_routes_lock);
474 	return r;
475 }
476 
477 
478 /*
479  * Given an AppleTalk network, find the device to use. This can be
480  * a simple lookup.
481  */
482 struct net_device *atrtr_get_dev(struct atalk_addr *sa)
483 {
484 	struct atalk_route *atr = atrtr_find(sa);
485 	return atr ? atr->dev : NULL;
486 }
487 
488 /* Set up a default router */
489 static void atrtr_set_default(struct net_device *dev)
490 {
491 	atrtr_default.dev	     = dev;
492 	atrtr_default.flags	     = RTF_UP;
493 	atrtr_default.gateway.s_net  = htons(0);
494 	atrtr_default.gateway.s_node = 0;
495 }
496 
497 /*
498  * Add a router. Basically make sure it looks valid and stuff the
499  * entry in the list. While it uses netranges we always set them to one
500  * entry to work like netatalk.
501  */
502 static int atrtr_create(struct rtentry *r, struct net_device *devhint)
503 {
504 	struct sockaddr_at *ta = (struct sockaddr_at *)&r->rt_dst;
505 	struct sockaddr_at *ga = (struct sockaddr_at *)&r->rt_gateway;
506 	struct atalk_route *rt;
507 	struct atalk_iface *iface, *riface;
508 	int retval = -EINVAL;
509 
510 	/*
511 	 * Fixme: Raise/Lower a routing change semaphore for these
512 	 * operations.
513 	 */
514 
515 	/* Validate the request */
516 	if (ta->sat_family != AF_APPLETALK ||
517 	    (!devhint && ga->sat_family != AF_APPLETALK))
518 		goto out;
519 
520 	/* Now walk the routing table and make our decisions */
521 	write_lock_bh(&atalk_routes_lock);
522 	for (rt = atalk_routes; rt; rt = rt->next) {
523 		if (r->rt_flags != rt->flags)
524 			continue;
525 
526 		if (ta->sat_addr.s_net == rt->target.s_net) {
527 			if (!(rt->flags & RTF_HOST))
528 				break;
529 			if (ta->sat_addr.s_node == rt->target.s_node)
530 				break;
531 		}
532 	}
533 
534 	if (!devhint) {
535 		riface = NULL;
536 
537 		read_lock_bh(&atalk_interfaces_lock);
538 		for (iface = atalk_interfaces; iface; iface = iface->next) {
539 			if (!riface &&
540 			    ntohs(ga->sat_addr.s_net) >=
541 					ntohs(iface->nets.nr_firstnet) &&
542 			    ntohs(ga->sat_addr.s_net) <=
543 					ntohs(iface->nets.nr_lastnet))
544 				riface = iface;
545 
546 			if (ga->sat_addr.s_net == iface->address.s_net &&
547 			    ga->sat_addr.s_node == iface->address.s_node)
548 				riface = iface;
549 		}
550 		read_unlock_bh(&atalk_interfaces_lock);
551 
552 		retval = -ENETUNREACH;
553 		if (!riface)
554 			goto out_unlock;
555 
556 		devhint = riface->dev;
557 	}
558 
559 	if (!rt) {
560 		rt = kzalloc(sizeof(*rt), GFP_ATOMIC);
561 
562 		retval = -ENOBUFS;
563 		if (!rt)
564 			goto out_unlock;
565 
566 		rt->next = atalk_routes;
567 		atalk_routes = rt;
568 	}
569 
570 	/* Fill in the routing entry */
571 	rt->target  = ta->sat_addr;
572 	dev_hold(devhint);
573 	rt->dev     = devhint;
574 	rt->flags   = r->rt_flags;
575 	rt->gateway = ga->sat_addr;
576 
577 	retval = 0;
578 out_unlock:
579 	write_unlock_bh(&atalk_routes_lock);
580 out:
581 	return retval;
582 }
583 
584 /* Delete a route. Find it and discard it */
585 static int atrtr_delete(struct atalk_addr * addr)
586 {
587 	struct atalk_route **r = &atalk_routes;
588 	int retval = 0;
589 	struct atalk_route *tmp;
590 
591 	write_lock_bh(&atalk_routes_lock);
592 	while ((tmp = *r) != NULL) {
593 		if (tmp->target.s_net == addr->s_net &&
594 		    (!(tmp->flags&RTF_GATEWAY) ||
595 		     tmp->target.s_node == addr->s_node)) {
596 			*r = tmp->next;
597 			dev_put(tmp->dev);
598 			kfree(tmp);
599 			goto out;
600 		}
601 		r = &tmp->next;
602 	}
603 	retval = -ENOENT;
604 out:
605 	write_unlock_bh(&atalk_routes_lock);
606 	return retval;
607 }
608 
609 /*
610  * Called when a device is downed. Just throw away any routes
611  * via it.
612  */
613 static void atrtr_device_down(struct net_device *dev)
614 {
615 	struct atalk_route **r = &atalk_routes;
616 	struct atalk_route *tmp;
617 
618 	write_lock_bh(&atalk_routes_lock);
619 	while ((tmp = *r) != NULL) {
620 		if (tmp->dev == dev) {
621 			*r = tmp->next;
622 			dev_put(dev);
623 			kfree(tmp);
624 		} else
625 			r = &tmp->next;
626 	}
627 	write_unlock_bh(&atalk_routes_lock);
628 
629 	if (atrtr_default.dev == dev)
630 		atrtr_set_default(NULL);
631 }
632 
633 /* Actually down the interface */
634 static inline void atalk_dev_down(struct net_device *dev)
635 {
636 	atrtr_device_down(dev);	/* Remove all routes for the device */
637 	aarp_device_down(dev);	/* Remove AARP entries for the device */
638 	atif_drop_device(dev);	/* Remove the device */
639 }
640 
641 /*
642  * A device event has occurred. Watch for devices going down and
643  * delete our use of them (iface and route).
644  */
645 static int ddp_device_event(struct notifier_block *this, unsigned long event,
646 			    void *ptr)
647 {
648 	struct net_device *dev = ptr;
649 
650 	if (!net_eq(dev_net(dev), &init_net))
651 		return NOTIFY_DONE;
652 
653 	if (event == NETDEV_DOWN)
654 		/* Discard any use of this */
655 		atalk_dev_down(dev);
656 
657 	return NOTIFY_DONE;
658 }
659 
660 /* ioctl calls. Shouldn't even need touching */
661 /* Device configuration ioctl calls */
662 static int atif_ioctl(int cmd, void __user *arg)
663 {
664 	static char aarp_mcast[6] = { 0x09, 0x00, 0x00, 0xFF, 0xFF, 0xFF };
665 	struct ifreq atreq;
666 	struct atalk_netrange *nr;
667 	struct sockaddr_at *sa;
668 	struct net_device *dev;
669 	struct atalk_iface *atif;
670 	int ct;
671 	int limit;
672 	struct rtentry rtdef;
673 	int add_route;
674 
675 	if (copy_from_user(&atreq, arg, sizeof(atreq)))
676 		return -EFAULT;
677 
678 	dev = __dev_get_by_name(&init_net, atreq.ifr_name);
679 	if (!dev)
680 		return -ENODEV;
681 
682 	sa = (struct sockaddr_at *)&atreq.ifr_addr;
683 	atif = atalk_find_dev(dev);
684 
685 	switch (cmd) {
686 		case SIOCSIFADDR:
687 			if (!capable(CAP_NET_ADMIN))
688 				return -EPERM;
689 			if (sa->sat_family != AF_APPLETALK)
690 				return -EINVAL;
691 			if (dev->type != ARPHRD_ETHER &&
692 			    dev->type != ARPHRD_LOOPBACK &&
693 			    dev->type != ARPHRD_LOCALTLK &&
694 			    dev->type != ARPHRD_PPP)
695 				return -EPROTONOSUPPORT;
696 
697 			nr = (struct atalk_netrange *)&sa->sat_zero[0];
698 			add_route = 1;
699 
700 			/*
701 			 * if this is a point-to-point iface, and we already
702 			 * have an iface for this AppleTalk address, then we
703 			 * should not add a route
704 			 */
705 			if ((dev->flags & IFF_POINTOPOINT) &&
706 			    atalk_find_interface(sa->sat_addr.s_net,
707 						 sa->sat_addr.s_node)) {
708 				printk(KERN_DEBUG "AppleTalk: point-to-point "
709 						  "interface added with "
710 						  "existing address\n");
711 				add_route = 0;
712 			}
713 
714 			/*
715 			 * Phase 1 is fine on LocalTalk but we don't do
716 			 * EtherTalk phase 1. Anyone wanting to add it go ahead.
717 			 */
718 			if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
719 				return -EPROTONOSUPPORT;
720 			if (sa->sat_addr.s_node == ATADDR_BCAST ||
721 			    sa->sat_addr.s_node == 254)
722 				return -EINVAL;
723 			if (atif) {
724 				/* Already setting address */
725 				if (atif->status & ATIF_PROBE)
726 					return -EBUSY;
727 
728 				atif->address.s_net  = sa->sat_addr.s_net;
729 				atif->address.s_node = sa->sat_addr.s_node;
730 				atrtr_device_down(dev);	/* Flush old routes */
731 			} else {
732 				atif = atif_add_device(dev, &sa->sat_addr);
733 				if (!atif)
734 					return -ENOMEM;
735 			}
736 			atif->nets = *nr;
737 
738 			/*
739 			 * Check if the chosen address is used. If so we
740 			 * error and atalkd will try another.
741 			 */
742 
743 			if (!(dev->flags & IFF_LOOPBACK) &&
744 			    !(dev->flags & IFF_POINTOPOINT) &&
745 			    atif_probe_device(atif) < 0) {
746 				atif_drop_device(dev);
747 				return -EADDRINUSE;
748 			}
749 
750 			/* Hey it worked - add the direct routes */
751 			sa = (struct sockaddr_at *)&rtdef.rt_gateway;
752 			sa->sat_family = AF_APPLETALK;
753 			sa->sat_addr.s_net  = atif->address.s_net;
754 			sa->sat_addr.s_node = atif->address.s_node;
755 			sa = (struct sockaddr_at *)&rtdef.rt_dst;
756 			rtdef.rt_flags = RTF_UP;
757 			sa->sat_family = AF_APPLETALK;
758 			sa->sat_addr.s_node = ATADDR_ANYNODE;
759 			if (dev->flags & IFF_LOOPBACK ||
760 			    dev->flags & IFF_POINTOPOINT)
761 				rtdef.rt_flags |= RTF_HOST;
762 
763 			/* Routerless initial state */
764 			if (nr->nr_firstnet == htons(0) &&
765 			    nr->nr_lastnet == htons(0xFFFE)) {
766 				sa->sat_addr.s_net = atif->address.s_net;
767 				atrtr_create(&rtdef, dev);
768 				atrtr_set_default(dev);
769 			} else {
770 				limit = ntohs(nr->nr_lastnet);
771 				if (limit - ntohs(nr->nr_firstnet) > 4096) {
772 					printk(KERN_WARNING "Too many routes/"
773 							    "iface.\n");
774 					return -EINVAL;
775 				}
776 				if (add_route)
777 					for (ct = ntohs(nr->nr_firstnet);
778 					     ct <= limit; ct++) {
779 						sa->sat_addr.s_net = htons(ct);
780 						atrtr_create(&rtdef, dev);
781 					}
782 			}
783 			dev_mc_add(dev, aarp_mcast, 6, 1);
784 			return 0;
785 
786 		case SIOCGIFADDR:
787 			if (!atif)
788 				return -EADDRNOTAVAIL;
789 
790 			sa->sat_family = AF_APPLETALK;
791 			sa->sat_addr = atif->address;
792 			break;
793 
794 		case SIOCGIFBRDADDR:
795 			if (!atif)
796 				return -EADDRNOTAVAIL;
797 
798 			sa->sat_family = AF_APPLETALK;
799 			sa->sat_addr.s_net = atif->address.s_net;
800 			sa->sat_addr.s_node = ATADDR_BCAST;
801 			break;
802 
803 		case SIOCATALKDIFADDR:
804 		case SIOCDIFADDR:
805 			if (!capable(CAP_NET_ADMIN))
806 				return -EPERM;
807 			if (sa->sat_family != AF_APPLETALK)
808 				return -EINVAL;
809 			atalk_dev_down(dev);
810 			break;
811 
812 		case SIOCSARP:
813 			if (!capable(CAP_NET_ADMIN))
814 				return -EPERM;
815 			if (sa->sat_family != AF_APPLETALK)
816 				return -EINVAL;
817 			/*
818 			 * for now, we only support proxy AARP on ELAP;
819 			 * we should be able to do it for LocalTalk, too.
820 			 */
821 			if (dev->type != ARPHRD_ETHER)
822 				return -EPROTONOSUPPORT;
823 
824 			/*
825 			 * atif points to the current interface on this network;
826 			 * we aren't concerned about its current status (at
827 			 * least for now), but it has all the settings about
828 			 * the network we're going to probe. Consequently, it
829 			 * must exist.
830 			 */
831 			if (!atif)
832 				return -EADDRNOTAVAIL;
833 
834 			nr = (struct atalk_netrange *)&(atif->nets);
835 			/*
836 			 * Phase 1 is fine on Localtalk but we don't do
837 			 * Ethertalk phase 1. Anyone wanting to add it go ahead.
838 			 */
839 			if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
840 				return -EPROTONOSUPPORT;
841 
842 			if (sa->sat_addr.s_node == ATADDR_BCAST ||
843 			    sa->sat_addr.s_node == 254)
844 				return -EINVAL;
845 
846 			/*
847 			 * Check if the chosen address is used. If so we
848 			 * error and ATCP will try another.
849 			 */
850 			if (atif_proxy_probe_device(atif, &(sa->sat_addr)) < 0)
851 				return -EADDRINUSE;
852 
853 			/*
854 			 * We now have an address on the local network, and
855 			 * the AARP code will defend it for us until we take it
856 			 * down. We don't set up any routes right now, because
857 			 * ATCP will install them manually via SIOCADDRT.
858 			 */
859 			break;
860 
861 		case SIOCDARP:
862 			if (!capable(CAP_NET_ADMIN))
863 				return -EPERM;
864 			if (sa->sat_family != AF_APPLETALK)
865 				return -EINVAL;
866 			if (!atif)
867 				return -EADDRNOTAVAIL;
868 
869 			/* give to aarp module to remove proxy entry */
870 			aarp_proxy_remove(atif->dev, &(sa->sat_addr));
871 			return 0;
872 	}
873 
874 	return copy_to_user(arg, &atreq, sizeof(atreq)) ? -EFAULT : 0;
875 }
876 
877 /* Routing ioctl() calls */
878 static int atrtr_ioctl(unsigned int cmd, void __user *arg)
879 {
880 	struct rtentry rt;
881 
882 	if (copy_from_user(&rt, arg, sizeof(rt)))
883 		return -EFAULT;
884 
885 	switch (cmd) {
886 		case SIOCDELRT:
887 			if (rt.rt_dst.sa_family != AF_APPLETALK)
888 				return -EINVAL;
889 			return atrtr_delete(&((struct sockaddr_at *)
890 						&rt.rt_dst)->sat_addr);
891 
892 		case SIOCADDRT: {
893 			struct net_device *dev = NULL;
894 			if (rt.rt_dev) {
895 				char name[IFNAMSIZ];
896 				if (copy_from_user(name, rt.rt_dev, IFNAMSIZ-1))
897 					return -EFAULT;
898 				name[IFNAMSIZ-1] = '\0';
899 				dev = __dev_get_by_name(&init_net, name);
900 				if (!dev)
901 					return -ENODEV;
902 			}
903 			return atrtr_create(&rt, dev);
904 		}
905 	}
906 	return -EINVAL;
907 }
908 
909 /**************************************************************************\
910 *                                                                          *
911 * Handling for system calls applied via the various interfaces to an       *
912 * AppleTalk socket object.                                                 *
913 *                                                                          *
914 \**************************************************************************/
915 
916 /*
917  * Checksum: This is 'optional'. It's quite likely also a good
918  * candidate for assembler hackery 8)
919  */
920 static unsigned long atalk_sum_partial(const unsigned char *data,
921 				       int len, unsigned long sum)
922 {
923 	/* This ought to be unwrapped neatly. I'll trust gcc for now */
924 	while (len--) {
925 		sum += *data;
926 		sum <<= 1;
927 		if (sum & 0x10000) {
928 			sum++;
929 			sum &= 0xffff;
930 		}
931 		data++;
932 	}
933 	return sum;
934 }
935 
936 /*  Checksum skb data --  similar to skb_checksum  */
937 static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
938 				   int len, unsigned long sum)
939 {
940 	int start = skb_headlen(skb);
941 	struct sk_buff *frag_iter;
942 	int i, copy;
943 
944 	/* checksum stuff in header space */
945 	if ( (copy = start - offset) > 0) {
946 		if (copy > len)
947 			copy = len;
948 		sum = atalk_sum_partial(skb->data + offset, copy, sum);
949 		if ( (len -= copy) == 0)
950 			return sum;
951 
952 		offset += copy;
953 	}
954 
955 	/* checksum stuff in frags */
956 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
957 		int end;
958 
959 		WARN_ON(start > offset + len);
960 
961 		end = start + skb_shinfo(skb)->frags[i].size;
962 		if ((copy = end - offset) > 0) {
963 			u8 *vaddr;
964 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
965 
966 			if (copy > len)
967 				copy = len;
968 			vaddr = kmap_skb_frag(frag);
969 			sum = atalk_sum_partial(vaddr + frag->page_offset +
970 						  offset - start, copy, sum);
971 			kunmap_skb_frag(vaddr);
972 
973 			if (!(len -= copy))
974 				return sum;
975 			offset += copy;
976 		}
977 		start = end;
978 	}
979 
980 	skb_walk_frags(skb, frag_iter) {
981 		int end;
982 
983 		WARN_ON(start > offset + len);
984 
985 		end = start + frag_iter->len;
986 		if ((copy = end - offset) > 0) {
987 			if (copy > len)
988 				copy = len;
989 			sum = atalk_sum_skb(frag_iter, offset - start,
990 					    copy, sum);
991 			if ((len -= copy) == 0)
992 				return sum;
993 			offset += copy;
994 		}
995 		start = end;
996 	}
997 
998 	BUG_ON(len > 0);
999 
1000 	return sum;
1001 }
1002 
1003 static __be16 atalk_checksum(const struct sk_buff *skb, int len)
1004 {
1005 	unsigned long sum;
1006 
1007 	/* skip header 4 bytes */
1008 	sum = atalk_sum_skb(skb, 4, len-4, 0);
1009 
1010 	/* Use 0xFFFF for 0. 0 itself means none */
1011 	return sum ? htons((unsigned short)sum) : htons(0xFFFF);
1012 }
1013 
1014 static struct proto ddp_proto = {
1015 	.name	  = "DDP",
1016 	.owner	  = THIS_MODULE,
1017 	.obj_size = sizeof(struct atalk_sock),
1018 };
1019 
1020 /*
1021  * Create a socket. Initialise the socket, blank the addresses
1022  * set the state.
1023  */
1024 static int atalk_create(struct net *net, struct socket *sock, int protocol)
1025 {
1026 	struct sock *sk;
1027 	int rc = -ESOCKTNOSUPPORT;
1028 
1029 	if (net != &init_net)
1030 		return -EAFNOSUPPORT;
1031 
1032 	/*
1033 	 * We permit SOCK_DGRAM and RAW is an extension. It is trivial to do
1034 	 * and gives you the full ELAP frame. Should be handy for CAP 8)
1035 	 */
1036 	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
1037 		goto out;
1038 	rc = -ENOMEM;
1039 	sk = sk_alloc(net, PF_APPLETALK, GFP_KERNEL, &ddp_proto);
1040 	if (!sk)
1041 		goto out;
1042 	rc = 0;
1043 	sock->ops = &atalk_dgram_ops;
1044 	sock_init_data(sock, sk);
1045 
1046 	/* Checksums on by default */
1047 	sock_set_flag(sk, SOCK_ZAPPED);
1048 out:
1049 	return rc;
1050 }
1051 
1052 /* Free a socket. No work needed */
1053 static int atalk_release(struct socket *sock)
1054 {
1055 	struct sock *sk = sock->sk;
1056 
1057 	if (sk) {
1058 		sock_orphan(sk);
1059 		sock->sk = NULL;
1060 		atalk_destroy_socket(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 		struct hlist_node *node;
1086 
1087 		sk_for_each(s, node, &atalk_sockets) {
1088 			struct atalk_sock *at = at_sk(s);
1089 
1090 			if (at->src_net == sat->sat_addr.s_net &&
1091 			    at->src_node == sat->sat_addr.s_node &&
1092 			    at->src_port == sat->sat_port)
1093 				goto try_next_port;
1094 		}
1095 
1096 		/* Wheee, it's free, assign and insert. */
1097 		__atalk_insert_socket(sk);
1098 		at_sk(sk)->src_port = sat->sat_port;
1099 		retval = 0;
1100 		goto out;
1101 
1102 try_next_port:;
1103 	}
1104 
1105 	retval = -EBUSY;
1106 out:
1107 	write_unlock_bh(&atalk_sockets_lock);
1108 	return retval;
1109 }
1110 
1111 static int atalk_autobind(struct sock *sk)
1112 {
1113 	struct atalk_sock *at = at_sk(sk);
1114 	struct sockaddr_at sat;
1115 	struct atalk_addr *ap = atalk_find_primary();
1116 	int n = -EADDRNOTAVAIL;
1117 
1118 	if (!ap || ap->s_net == htons(ATADDR_ANYNET))
1119 		goto out;
1120 
1121 	at->src_net  = sat.sat_addr.s_net  = ap->s_net;
1122 	at->src_node = sat.sat_addr.s_node = ap->s_node;
1123 
1124 	n = atalk_pick_and_bind_port(sk, &sat);
1125 	if (!n)
1126 		sock_reset_flag(sk, SOCK_ZAPPED);
1127 out:
1128 	return n;
1129 }
1130 
1131 /* Set the address 'our end' of the connection */
1132 static int atalk_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1133 {
1134 	struct sockaddr_at *addr = (struct sockaddr_at *)uaddr;
1135 	struct sock *sk = sock->sk;
1136 	struct atalk_sock *at = at_sk(sk);
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 	if (addr->sat_addr.s_net == htons(ATADDR_ANYNET)) {
1146 		struct atalk_addr *ap = atalk_find_primary();
1147 
1148 		if (!ap)
1149 			return -EADDRNOTAVAIL;
1150 
1151 		at->src_net  = addr->sat_addr.s_net = ap->s_net;
1152 		at->src_node = addr->sat_addr.s_node= ap->s_node;
1153 	} else {
1154 		if (!atalk_find_interface(addr->sat_addr.s_net,
1155 					  addr->sat_addr.s_node))
1156 			return -EADDRNOTAVAIL;
1157 
1158 		at->src_net  = addr->sat_addr.s_net;
1159 		at->src_node = addr->sat_addr.s_node;
1160 	}
1161 
1162 	if (addr->sat_port == ATADDR_ANYPORT) {
1163 		int n = atalk_pick_and_bind_port(sk, addr);
1164 
1165 		if (n < 0)
1166 			return n;
1167 	} else {
1168 		at->src_port = addr->sat_port;
1169 
1170 		if (atalk_find_or_insert_socket(sk, addr))
1171 			return -EADDRINUSE;
1172 	}
1173 
1174 	sock_reset_flag(sk, SOCK_ZAPPED);
1175 	return 0;
1176 }
1177 
1178 /* Set the address we talk to */
1179 static int atalk_connect(struct socket *sock, struct sockaddr *uaddr,
1180 			 int addr_len, int flags)
1181 {
1182 	struct sock *sk = sock->sk;
1183 	struct atalk_sock *at = at_sk(sk);
1184 	struct sockaddr_at *addr;
1185 
1186 	sk->sk_state   = TCP_CLOSE;
1187 	sock->state = SS_UNCONNECTED;
1188 
1189 	if (addr_len != sizeof(*addr))
1190 		return -EINVAL;
1191 
1192 	addr = (struct sockaddr_at *)uaddr;
1193 
1194 	if (addr->sat_family != AF_APPLETALK)
1195 		return -EAFNOSUPPORT;
1196 
1197 	if (addr->sat_addr.s_node == ATADDR_BCAST &&
1198 	    !sock_flag(sk, SOCK_BROADCAST)) {
1199 #if 1
1200 		printk(KERN_WARNING "%s is broken and did not set "
1201 				    "SO_BROADCAST. It will break when 2.2 is "
1202 				    "released.\n",
1203 			current->comm);
1204 #else
1205 		return -EACCES;
1206 #endif
1207 	}
1208 
1209 	if (sock_flag(sk, SOCK_ZAPPED))
1210 		if (atalk_autobind(sk) < 0)
1211 			return -EBUSY;
1212 
1213 	if (!atrtr_get_dev(&addr->sat_addr))
1214 		return -ENETUNREACH;
1215 
1216 	at->dest_port = addr->sat_port;
1217 	at->dest_net  = addr->sat_addr.s_net;
1218 	at->dest_node = addr->sat_addr.s_node;
1219 
1220 	sock->state  = SS_CONNECTED;
1221 	sk->sk_state = TCP_ESTABLISHED;
1222 	return 0;
1223 }
1224 
1225 /*
1226  * Find the name of an AppleTalk socket. Just copy the right
1227  * fields into the sockaddr.
1228  */
1229 static int atalk_getname(struct socket *sock, struct sockaddr *uaddr,
1230 			 int *uaddr_len, int peer)
1231 {
1232 	struct sockaddr_at sat;
1233 	struct sock *sk = sock->sk;
1234 	struct atalk_sock *at = at_sk(sk);
1235 
1236 	if (sock_flag(sk, SOCK_ZAPPED))
1237 		if (atalk_autobind(sk) < 0)
1238 			return -ENOBUFS;
1239 
1240 	*uaddr_len = sizeof(struct sockaddr_at);
1241 	memset(&sat.sat_zero, 0, sizeof(sat.sat_zero));
1242 
1243 	if (peer) {
1244 		if (sk->sk_state != TCP_ESTABLISHED)
1245 			return -ENOTCONN;
1246 
1247 		sat.sat_addr.s_net  = at->dest_net;
1248 		sat.sat_addr.s_node = at->dest_node;
1249 		sat.sat_port	    = at->dest_port;
1250 	} else {
1251 		sat.sat_addr.s_net  = at->src_net;
1252 		sat.sat_addr.s_node = at->src_node;
1253 		sat.sat_port	    = at->src_port;
1254 	}
1255 
1256 	sat.sat_family = AF_APPLETALK;
1257 	memcpy(uaddr, &sat, sizeof(sat));
1258 	return 0;
1259 }
1260 
1261 #if defined(CONFIG_IPDDP) || defined(CONFIG_IPDDP_MODULE)
1262 static __inline__ int is_ip_over_ddp(struct sk_buff *skb)
1263 {
1264 	return skb->data[12] == 22;
1265 }
1266 
1267 static int handle_ip_over_ddp(struct sk_buff *skb)
1268 {
1269 	struct net_device *dev = __dev_get_by_name(&init_net, "ipddp0");
1270 	struct net_device_stats *stats;
1271 
1272 	/* This needs to be able to handle ipddp"N" devices */
1273 	if (!dev) {
1274 		kfree_skb(skb);
1275 		return NET_RX_DROP;
1276 	}
1277 
1278 	skb->protocol = htons(ETH_P_IP);
1279 	skb_pull(skb, 13);
1280 	skb->dev   = dev;
1281 	skb_reset_transport_header(skb);
1282 
1283 	stats = netdev_priv(dev);
1284 	stats->rx_packets++;
1285 	stats->rx_bytes += skb->len + 13;
1286 	return netif_rx(skb);  /* Send the SKB up to a higher place. */
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 int atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
1295 			      struct ddpehdr *ddp, __u16 len_hops, int origlen)
1296 {
1297 	struct atalk_route *rt;
1298 	struct atalk_addr ta;
1299 
1300 	/*
1301 	 * Don't route multicast, etc., packets, or packets sent to "this
1302 	 * network"
1303 	 */
1304 	if (skb->pkt_type != PACKET_HOST || !ddp->deh_dnet) {
1305 		/*
1306 		 * FIXME:
1307 		 *
1308 		 * Can it ever happen that a packet is from a PPP iface and
1309 		 * needs to be broadcast onto the default network?
1310 		 */
1311 		if (dev->type == ARPHRD_PPP)
1312 			printk(KERN_DEBUG "AppleTalk: didn't forward broadcast "
1313 					  "packet received from PPP iface\n");
1314 		goto free_it;
1315 	}
1316 
1317 	ta.s_net  = ddp->deh_dnet;
1318 	ta.s_node = ddp->deh_dnode;
1319 
1320 	/* Route the packet */
1321 	rt = atrtr_find(&ta);
1322 	/* increment hops count */
1323 	len_hops += 1 << 10;
1324 	if (!rt || !(len_hops & (15 << 10)))
1325 		goto free_it;
1326 
1327 	/* FIXME: use skb->cb to be able to use shared skbs */
1328 
1329 	/*
1330 	 * Route goes through another gateway, so set the target to the
1331 	 * gateway instead.
1332 	 */
1333 
1334 	if (rt->flags & RTF_GATEWAY) {
1335 		ta.s_net  = rt->gateway.s_net;
1336 		ta.s_node = rt->gateway.s_node;
1337 	}
1338 
1339 	/* Fix up skb->len field */
1340 	skb_trim(skb, min_t(unsigned int, origlen,
1341 			    (rt->dev->hard_header_len +
1342 			     ddp_dl->header_length + (len_hops & 1023))));
1343 
1344 	/* FIXME: use skb->cb to be able to use shared skbs */
1345 	ddp->deh_len_hops = htons(len_hops);
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 		skb = nskb;
1363 	} else
1364 		skb = skb_unshare(skb, GFP_ATOMIC);
1365 
1366 	/*
1367 	 * If the buffer didn't vanish into the lack of space bitbucket we can
1368 	 * send it.
1369 	 */
1370 	if (skb == NULL)
1371 		goto drop;
1372 
1373 	if (aarp_send_ddp(rt->dev, skb, &ta, NULL) == NET_XMIT_DROP)
1374 		return NET_RX_DROP;
1375 	return NET_RX_SUCCESS;
1376 free_it:
1377 	kfree_skb(skb);
1378 drop:
1379 	return NET_RX_DROP;
1380 }
1381 
1382 /**
1383  *	atalk_rcv - Receive a packet (in skb) from device dev
1384  *	@skb - packet received
1385  *	@dev - network device where the packet comes from
1386  *	@pt - packet type
1387  *
1388  *	Receive a packet (in skb) from device dev. This has come from the SNAP
1389  *	decoder, and on entry skb->transport_header is the DDP header, skb->len
1390  *	is the DDP header, skb->len is the DDP length. The physical headers
1391  *	have been extracted. PPP should probably pass frames marked as for this
1392  *	layer.  [ie ARPHRD_ETHERTALK]
1393  */
1394 static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
1395 		     struct packet_type *pt, struct net_device *orig_dev)
1396 {
1397 	struct ddpehdr *ddp;
1398 	struct sock *sock;
1399 	struct atalk_iface *atif;
1400 	struct sockaddr_at tosat;
1401 	int origlen;
1402 	__u16 len_hops;
1403 
1404 	if (!net_eq(dev_net(dev), &init_net))
1405 		goto drop;
1406 
1407 	/* Don't mangle buffer if shared */
1408 	if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
1409 		goto out;
1410 
1411 	/* Size check and make sure header is contiguous */
1412 	if (!pskb_may_pull(skb, sizeof(*ddp)))
1413 		goto drop;
1414 
1415 	ddp = ddp_hdr(skb);
1416 
1417 	len_hops = ntohs(ddp->deh_len_hops);
1418 
1419 	/* Trim buffer in case of stray trailing data */
1420 	origlen = skb->len;
1421 	skb_trim(skb, min_t(unsigned int, skb->len, len_hops & 1023));
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 atalk_checksum() or recvmsg()).
1427 	 */
1428 	if (skb->len < sizeof(*ddp) || skb->len < (len_hops & 1023)) {
1429 		pr_debug("AppleTalk: dropping corrupted frame (deh_len=%u, "
1430 			 "skb->len=%u)\n", len_hops & 1023, skb->len);
1431 		goto drop;
1432 	}
1433 
1434 	/*
1435 	 * Any checksums. Note we don't do htons() on this == is assumed to be
1436 	 * valid for net byte orders all over the networking code...
1437 	 */
1438 	if (ddp->deh_sum &&
1439 	    atalk_checksum(skb, len_hops & 1023) != ddp->deh_sum)
1440 		/* Not a valid AppleTalk frame - dustbin time */
1441 		goto drop;
1442 
1443 	/* Check the packet is aimed at us */
1444 	if (!ddp->deh_dnet)	/* Net 0 is 'this network' */
1445 		atif = atalk_find_anynet(ddp->deh_dnode, dev);
1446 	else
1447 		atif = atalk_find_interface(ddp->deh_dnet, ddp->deh_dnode);
1448 
1449 	if (!atif) {
1450 		/* Not ours, so we route the packet via the correct
1451 		 * AppleTalk iface
1452 		 */
1453 		return atalk_route_packet(skb, dev, ddp, len_hops, origlen);
1454 	}
1455 
1456 	/* if IP over DDP is not selected this code will be optimized out */
1457 	if (is_ip_over_ddp(skb))
1458 		return handle_ip_over_ddp(skb);
1459 	/*
1460 	 * Which socket - atalk_search_socket() looks for a *full match*
1461 	 * of the <net, node, port> tuple.
1462 	 */
1463 	tosat.sat_addr.s_net  = ddp->deh_dnet;
1464 	tosat.sat_addr.s_node = ddp->deh_dnode;
1465 	tosat.sat_port	      = ddp->deh_dport;
1466 
1467 	sock = atalk_search_socket(&tosat, atif);
1468 	if (!sock) /* But not one of our sockets */
1469 		goto drop;
1470 
1471 	/* Queue packet (standard) */
1472 	skb->sk = sock;
1473 
1474 	if (sock_queue_rcv_skb(sock, skb) < 0)
1475 		goto drop;
1476 
1477 	return NET_RX_SUCCESS;
1478 
1479 drop:
1480 	kfree_skb(skb);
1481 out:
1482 	return NET_RX_DROP;
1483 
1484 }
1485 
1486 /*
1487  * Receive a LocalTalk frame. We make some demands on the caller here.
1488  * Caller must provide enough headroom on the packet to pull the short
1489  * header and append a long one.
1490  */
1491 static int ltalk_rcv(struct sk_buff *skb, struct net_device *dev,
1492 		     struct packet_type *pt, struct net_device *orig_dev)
1493 {
1494 	if (!net_eq(dev_net(dev), &init_net))
1495 		goto freeit;
1496 
1497 	/* Expand any short form frames */
1498 	if (skb_mac_header(skb)[2] == 1) {
1499 		struct ddpehdr *ddp;
1500 		/* Find our address */
1501 		struct atalk_addr *ap = atalk_find_dev_addr(dev);
1502 
1503 		if (!ap || skb->len < sizeof(__be16) || skb->len > 1023)
1504 			goto freeit;
1505 
1506 		/* Don't mangle buffer if shared */
1507 		if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
1508 			return 0;
1509 
1510 		/*
1511 		 * The push leaves us with a ddephdr not an shdr, and
1512 		 * handily the port bytes in the right place preset.
1513 		 */
1514 		ddp = (struct ddpehdr *) skb_push(skb, sizeof(*ddp) - 4);
1515 
1516 		/* Now fill in the long header */
1517 
1518 		/*
1519 		 * These two first. The mac overlays the new source/dest
1520 		 * network information so we MUST copy these before
1521 		 * we write the network numbers !
1522 		 */
1523 
1524 		ddp->deh_dnode = skb_mac_header(skb)[0];     /* From physical header */
1525 		ddp->deh_snode = skb_mac_header(skb)[1];     /* From physical header */
1526 
1527 		ddp->deh_dnet  = ap->s_net;	/* Network number */
1528 		ddp->deh_snet  = ap->s_net;
1529 		ddp->deh_sum   = 0;		/* No checksum */
1530 		/*
1531 		 * Not sure about this bit...
1532 		 */
1533 		/* Non routable, so force a drop if we slip up later */
1534 		ddp->deh_len_hops = htons(skb->len + (DDP_MAXHOPS << 10));
1535 	}
1536 	skb_reset_transport_header(skb);
1537 
1538 	return atalk_rcv(skb, dev, pt, orig_dev);
1539 freeit:
1540 	kfree_skb(skb);
1541 	return 0;
1542 }
1543 
1544 static int atalk_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
1545 			 size_t len)
1546 {
1547 	struct sock *sk = sock->sk;
1548 	struct atalk_sock *at = at_sk(sk);
1549 	struct sockaddr_at *usat = (struct sockaddr_at *)msg->msg_name;
1550 	int flags = msg->msg_flags;
1551 	int loopback = 0;
1552 	struct sockaddr_at local_satalk, gsat;
1553 	struct sk_buff *skb;
1554 	struct net_device *dev;
1555 	struct ddpehdr *ddp;
1556 	int size;
1557 	struct atalk_route *rt;
1558 	int err;
1559 
1560 	if (flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT))
1561 		return -EINVAL;
1562 
1563 	if (len > DDP_MAXSZ)
1564 		return -EMSGSIZE;
1565 
1566 	if (usat) {
1567 		if (sock_flag(sk, SOCK_ZAPPED))
1568 			if (atalk_autobind(sk) < 0)
1569 				return -EBUSY;
1570 
1571 		if (msg->msg_namelen < sizeof(*usat) ||
1572 		    usat->sat_family != AF_APPLETALK)
1573 			return -EINVAL;
1574 
1575 		/* netatalk didn't implement this check */
1576 		if (usat->sat_addr.s_node == ATADDR_BCAST &&
1577 		    !sock_flag(sk, SOCK_BROADCAST)) {
1578 			return -EPERM;
1579 		}
1580 	} else {
1581 		if (sk->sk_state != TCP_ESTABLISHED)
1582 			return -ENOTCONN;
1583 		usat = &local_satalk;
1584 		usat->sat_family      = AF_APPLETALK;
1585 		usat->sat_port	      = at->dest_port;
1586 		usat->sat_addr.s_node = at->dest_node;
1587 		usat->sat_addr.s_net  = at->dest_net;
1588 	}
1589 
1590 	/* Build a packet */
1591 	SOCK_DEBUG(sk, "SK %p: Got address.\n", sk);
1592 
1593 	/* For headers */
1594 	size = sizeof(struct ddpehdr) + len + ddp_dl->header_length;
1595 
1596 	if (usat->sat_addr.s_net || usat->sat_addr.s_node == ATADDR_ANYNODE) {
1597 		rt = atrtr_find(&usat->sat_addr);
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 	}
1606 	if (!rt)
1607 		return -ENETUNREACH;
1608 
1609 	dev = rt->dev;
1610 
1611 	SOCK_DEBUG(sk, "SK %p: Size needed %d, device %s\n",
1612 			sk, size, dev->name);
1613 
1614 	size += dev->hard_header_len;
1615 	skb = sock_alloc_send_skb(sk, size, (flags & MSG_DONTWAIT), &err);
1616 	if (!skb)
1617 		return err;
1618 
1619 	skb->sk = sk;
1620 	skb_reserve(skb, ddp_dl->header_length);
1621 	skb_reserve(skb, dev->hard_header_len);
1622 	skb->dev = dev;
1623 
1624 	SOCK_DEBUG(sk, "SK %p: Begin build.\n", sk);
1625 
1626 	ddp = (struct ddpehdr *)skb_put(skb, sizeof(struct ddpehdr));
1627 	ddp->deh_len_hops  = htons(len + sizeof(*ddp));
1628 	ddp->deh_dnet  = usat->sat_addr.s_net;
1629 	ddp->deh_snet  = at->src_net;
1630 	ddp->deh_dnode = usat->sat_addr.s_node;
1631 	ddp->deh_snode = at->src_node;
1632 	ddp->deh_dport = usat->sat_port;
1633 	ddp->deh_sport = at->src_port;
1634 
1635 	SOCK_DEBUG(sk, "SK %p: Copy user data (%Zd bytes).\n", sk, len);
1636 
1637 	err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1638 	if (err) {
1639 		kfree_skb(skb);
1640 		return -EFAULT;
1641 	}
1642 
1643 	if (sk->sk_no_check == 1)
1644 		ddp->deh_sum = 0;
1645 	else
1646 		ddp->deh_sum = atalk_checksum(skb, len + sizeof(*ddp));
1647 
1648 	/*
1649 	 * Loopback broadcast packets to non gateway targets (ie routes
1650 	 * to group we are in)
1651 	 */
1652 	if (ddp->deh_dnode == ATADDR_BCAST &&
1653 	    !(rt->flags & RTF_GATEWAY) && !(dev->flags & IFF_LOOPBACK)) {
1654 		struct sk_buff *skb2 = skb_copy(skb, GFP_KERNEL);
1655 
1656 		if (skb2) {
1657 			loopback = 1;
1658 			SOCK_DEBUG(sk, "SK %p: send out(copy).\n", sk);
1659 			/*
1660 			 * If it fails it is queued/sent above in the aarp queue
1661 			 */
1662 			aarp_send_ddp(dev, skb2, &usat->sat_addr, NULL);
1663 		}
1664 	}
1665 
1666 	if (dev->flags & IFF_LOOPBACK || loopback) {
1667 		SOCK_DEBUG(sk, "SK %p: Loop back.\n", sk);
1668 		/* loop back */
1669 		skb_orphan(skb);
1670 		if (ddp->deh_dnode == ATADDR_BCAST) {
1671 			struct atalk_addr at_lo;
1672 
1673 			at_lo.s_node = 0;
1674 			at_lo.s_net  = 0;
1675 
1676 			rt = atrtr_find(&at_lo);
1677 			if (!rt) {
1678 				kfree_skb(skb);
1679 				return -ENETUNREACH;
1680 			}
1681 			dev = rt->dev;
1682 			skb->dev = dev;
1683 		}
1684 		ddp_dl->request(ddp_dl, skb, dev->dev_addr);
1685 	} else {
1686 		SOCK_DEBUG(sk, "SK %p: send out.\n", sk);
1687 		if (rt->flags & RTF_GATEWAY) {
1688 		    gsat.sat_addr = rt->gateway;
1689 		    usat = &gsat;
1690 		}
1691 
1692 		/*
1693 		 * If it fails it is queued/sent above in the aarp queue
1694 		 */
1695 		aarp_send_ddp(dev, skb, &usat->sat_addr, NULL);
1696 	}
1697 	SOCK_DEBUG(sk, "SK %p: Done write (%Zd).\n", sk, len);
1698 
1699 	return len;
1700 }
1701 
1702 static int atalk_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
1703 			 size_t size, int flags)
1704 {
1705 	struct sock *sk = sock->sk;
1706 	struct sockaddr_at *sat = (struct sockaddr_at *)msg->msg_name;
1707 	struct ddpehdr *ddp;
1708 	int copied = 0;
1709 	int offset = 0;
1710 	int err = 0;
1711 	struct sk_buff *skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
1712 						flags & MSG_DONTWAIT, &err);
1713 	if (!skb)
1714 		return err;
1715 
1716 	/* FIXME: use skb->cb to be able to use shared skbs */
1717 	ddp = ddp_hdr(skb);
1718 	copied = ntohs(ddp->deh_len_hops) & 1023;
1719 
1720 	if (sk->sk_type != SOCK_RAW) {
1721 		offset = sizeof(*ddp);
1722 		copied -= offset;
1723 	}
1724 
1725 	if (copied > size) {
1726 		copied = size;
1727 		msg->msg_flags |= MSG_TRUNC;
1728 	}
1729 	err = skb_copy_datagram_iovec(skb, offset, msg->msg_iov, copied);
1730 
1731 	if (!err) {
1732 		if (sat) {
1733 			sat->sat_family      = AF_APPLETALK;
1734 			sat->sat_port        = ddp->deh_sport;
1735 			sat->sat_addr.s_node = ddp->deh_snode;
1736 			sat->sat_addr.s_net  = ddp->deh_snet;
1737 		}
1738 		msg->msg_namelen = sizeof(*sat);
1739 	}
1740 
1741 	skb_free_datagram(sk, skb);	/* Free the datagram. */
1742 	return err ? : copied;
1743 }
1744 
1745 
1746 /*
1747  * AppleTalk ioctl calls.
1748  */
1749 static int atalk_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1750 {
1751 	int rc = -ENOIOCTLCMD;
1752 	struct sock *sk = sock->sk;
1753 	void __user *argp = (void __user *)arg;
1754 
1755 	switch (cmd) {
1756 		/* Protocol layer */
1757 		case TIOCOUTQ: {
1758 			long amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
1759 
1760 			if (amount < 0)
1761 				amount = 0;
1762 			rc = put_user(amount, (int __user *)argp);
1763 			break;
1764 		}
1765 		case TIOCINQ: {
1766 			/*
1767 			 * These two are safe on a single CPU system as only
1768 			 * user tasks fiddle here
1769 			 */
1770 			struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1771 			long amount = 0;
1772 
1773 			if (skb)
1774 				amount = skb->len - sizeof(struct ddpehdr);
1775 			rc = put_user(amount, (int __user *)argp);
1776 			break;
1777 		}
1778 		case SIOCGSTAMP:
1779 			rc = sock_get_timestamp(sk, argp);
1780 			break;
1781 		case SIOCGSTAMPNS:
1782 			rc = sock_get_timestampns(sk, argp);
1783 			break;
1784 		/* Routing */
1785 		case SIOCADDRT:
1786 		case SIOCDELRT:
1787 			rc = -EPERM;
1788 			if (capable(CAP_NET_ADMIN))
1789 				rc = atrtr_ioctl(cmd, argp);
1790 			break;
1791 		/* Interface */
1792 		case SIOCGIFADDR:
1793 		case SIOCSIFADDR:
1794 		case SIOCGIFBRDADDR:
1795 		case SIOCATALKDIFADDR:
1796 		case SIOCDIFADDR:
1797 		case SIOCSARP:		/* proxy AARP */
1798 		case SIOCDARP:		/* proxy AARP */
1799 			rtnl_lock();
1800 			rc = atif_ioctl(cmd, argp);
1801 			rtnl_unlock();
1802 			break;
1803 	}
1804 
1805 	return rc;
1806 }
1807 
1808 
1809 #ifdef CONFIG_COMPAT
1810 static int atalk_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1811 {
1812 	/*
1813 	 * All Appletalk ioctls except SIOCATALKDIFADDR are standard.  And
1814 	 * SIOCATALKDIFADDR is handled by upper layer as well, so there is
1815 	 * nothing to do.  Eventually SIOCATALKDIFADDR should be moved
1816 	 * here so there is no generic SIOCPROTOPRIVATE translation in the
1817 	 * system.
1818 	 */
1819 	return -ENOIOCTLCMD;
1820 }
1821 #endif
1822 
1823 
1824 static struct net_proto_family atalk_family_ops = {
1825 	.family		= PF_APPLETALK,
1826 	.create		= atalk_create,
1827 	.owner		= THIS_MODULE,
1828 };
1829 
1830 static const struct proto_ops SOCKOPS_WRAPPED(atalk_dgram_ops) = {
1831 	.family		= PF_APPLETALK,
1832 	.owner		= THIS_MODULE,
1833 	.release	= atalk_release,
1834 	.bind		= atalk_bind,
1835 	.connect	= atalk_connect,
1836 	.socketpair	= sock_no_socketpair,
1837 	.accept		= sock_no_accept,
1838 	.getname	= atalk_getname,
1839 	.poll		= datagram_poll,
1840 	.ioctl		= atalk_ioctl,
1841 #ifdef CONFIG_COMPAT
1842 	.compat_ioctl	= atalk_compat_ioctl,
1843 #endif
1844 	.listen		= sock_no_listen,
1845 	.shutdown	= sock_no_shutdown,
1846 	.setsockopt	= sock_no_setsockopt,
1847 	.getsockopt	= sock_no_getsockopt,
1848 	.sendmsg	= atalk_sendmsg,
1849 	.recvmsg	= atalk_recvmsg,
1850 	.mmap		= sock_no_mmap,
1851 	.sendpage	= sock_no_sendpage,
1852 };
1853 
1854 SOCKOPS_WRAP(atalk_dgram, PF_APPLETALK);
1855 
1856 static struct notifier_block ddp_notifier = {
1857 	.notifier_call	= ddp_device_event,
1858 };
1859 
1860 static struct packet_type ltalk_packet_type __read_mostly = {
1861 	.type		= cpu_to_be16(ETH_P_LOCALTALK),
1862 	.func		= ltalk_rcv,
1863 };
1864 
1865 static struct packet_type ppptalk_packet_type __read_mostly = {
1866 	.type		= cpu_to_be16(ETH_P_PPPTALK),
1867 	.func		= atalk_rcv,
1868 };
1869 
1870 static unsigned char ddp_snap_id[] = { 0x08, 0x00, 0x07, 0x80, 0x9B };
1871 
1872 /* Export symbols for use by drivers when AppleTalk is a module */
1873 EXPORT_SYMBOL(atrtr_get_dev);
1874 EXPORT_SYMBOL(atalk_find_dev_addr);
1875 
1876 static const char atalk_err_snap[] __initconst =
1877 	KERN_CRIT "Unable to register DDP with SNAP.\n";
1878 
1879 /* Called by proto.c on kernel start up */
1880 static int __init atalk_init(void)
1881 {
1882 	int rc = proto_register(&ddp_proto, 0);
1883 
1884 	if (rc != 0)
1885 		goto out;
1886 
1887 	(void)sock_register(&atalk_family_ops);
1888 	ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv);
1889 	if (!ddp_dl)
1890 		printk(atalk_err_snap);
1891 
1892 	dev_add_pack(&ltalk_packet_type);
1893 	dev_add_pack(&ppptalk_packet_type);
1894 
1895 	register_netdevice_notifier(&ddp_notifier);
1896 	aarp_proto_init();
1897 	atalk_proc_init();
1898 	atalk_register_sysctl();
1899 out:
1900 	return rc;
1901 }
1902 module_init(atalk_init);
1903 
1904 /*
1905  * No explicit module reference count manipulation is needed in the
1906  * protocol. Socket layer sets module reference count for us
1907  * and interfaces reference counting is done
1908  * by the network device layer.
1909  *
1910  * Ergo, before the AppleTalk module can be removed, all AppleTalk
1911  * sockets be closed from user space.
1912  */
1913 static void __exit atalk_exit(void)
1914 {
1915 #ifdef CONFIG_SYSCTL
1916 	atalk_unregister_sysctl();
1917 #endif /* CONFIG_SYSCTL */
1918 	atalk_proc_exit();
1919 	aarp_cleanup_module();	/* General aarp clean-up. */
1920 	unregister_netdevice_notifier(&ddp_notifier);
1921 	dev_remove_pack(&ltalk_packet_type);
1922 	dev_remove_pack(&ppptalk_packet_type);
1923 	unregister_snap_client(ddp_dl);
1924 	sock_unregister(PF_APPLETALK);
1925 	proto_unregister(&ddp_proto);
1926 }
1927 module_exit(atalk_exit);
1928 
1929 MODULE_LICENSE("GPL");
1930 MODULE_AUTHOR("Alan Cox <alan@lxorguk.ukuu.org.uk>");
1931 MODULE_DESCRIPTION("AppleTalk 0.20\n");
1932 MODULE_ALIAS_NETPROTO(PF_APPLETALK);
1933