xref: /kernel/linux/linux-5.10/net/appletalk/ddp.c (revision 8c2ecf20)
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *	DDP:	An implementation of the AppleTalk DDP protocol for
4 *		Ethernet 'ELAP'.
5 *
6 *		Alan Cox  <alan@lxorguk.ukuu.org.uk>
7 *
8 *		With more than a little assistance from
9 *
10 *		Wesley Craig <netatalk@umich.edu>
11 *
12 *	Fixes:
13 *		Neil Horman		:	Added missing device ioctls
14 *		Michael Callahan	:	Made routing work
15 *		Wesley Craig		:	Fix probing to listen to a
16 *						passed node id.
17 *		Alan Cox		:	Added send/recvmsg support
18 *		Alan Cox		:	Moved at. to protinfo in
19 *						socket.
20 *		Alan Cox		:	Added firewall hooks.
21 *		Alan Cox		:	Supports new ARPHRD_LOOPBACK
22 *		Christer Weinigel	: 	Routing and /proc fixes.
23 *		Bradford Johnson	:	LocalTalk.
24 *		Tom Dyas		:	Module support.
25 *		Alan Cox		:	Hooks for PPP (based on the
26 *						LocalTalk hook).
27 *		Alan Cox		:	Posix bits
28 *		Alan Cox/Mike Freeman	:	Possible fix to NBP problems
29 *		Bradford Johnson	:	IP-over-DDP (experimental)
30 *		Jay Schulist		:	Moved IP-over-DDP to its own
31 *						driver file. (ipddp.c & ipddp.h)
32 *		Jay Schulist		:	Made work as module with
33 *						AppleTalk drivers, cleaned it.
34 *		Rob Newberry		:	Added proxy AARP and AARP
35 *						procfs, moved probing to AARP
36 *						module.
37 *              Adrian Sun/
38 *              Michael Zuelsdorff      :       fix for net.0 packets. don't
39 *                                              allow illegal ether/tokentalk
40 *                                              port assignment. we lose a
41 *                                              valid localtalk port as a
42 *                                              result.
43 *		Arnaldo C. de Melo	:	Cleanup, in preparation for
44 *						shared skb support 8)
45 *		Arnaldo C. de Melo	:	Move proc stuff to atalk_proc.c,
46 *						use seq_file
47 */
48
49#include <linux/capability.h>
50#include <linux/module.h>
51#include <linux/if_arp.h>
52#include <linux/termios.h>	/* For TIOCOUTQ/INQ */
53#include <linux/compat.h>
54#include <linux/slab.h>
55#include <net/datalink.h>
56#include <net/psnap.h>
57#include <net/sock.h>
58#include <net/tcp_states.h>
59#include <net/route.h>
60#include <net/compat.h>
61#include <linux/atalk.h>
62#include <linux/highmem.h>
63
64struct datalink_proto *ddp_dl, *aarp_dl;
65static const struct proto_ops atalk_dgram_ops;
66
67/**************************************************************************\
68*                                                                          *
69* Handlers for the socket list.                                            *
70*                                                                          *
71\**************************************************************************/
72
73HLIST_HEAD(atalk_sockets);
74DEFINE_RWLOCK(atalk_sockets_lock);
75
76static inline void __atalk_insert_socket(struct sock *sk)
77{
78	sk_add_node(sk, &atalk_sockets);
79}
80
81static inline void atalk_remove_socket(struct sock *sk)
82{
83	write_lock_bh(&atalk_sockets_lock);
84	sk_del_node_init(sk);
85	write_unlock_bh(&atalk_sockets_lock);
86}
87
88static struct sock *atalk_search_socket(struct sockaddr_at *to,
89					struct atalk_iface *atif)
90{
91	struct sock *s;
92
93	read_lock_bh(&atalk_sockets_lock);
94	sk_for_each(s, &atalk_sockets) {
95		struct atalk_sock *at = at_sk(s);
96
97		if (to->sat_port != at->src_port)
98			continue;
99
100		if (to->sat_addr.s_net == ATADDR_ANYNET &&
101		    to->sat_addr.s_node == ATADDR_BCAST)
102			goto found;
103
104		if (to->sat_addr.s_net == at->src_net &&
105		    (to->sat_addr.s_node == at->src_node ||
106		     to->sat_addr.s_node == ATADDR_BCAST ||
107		     to->sat_addr.s_node == ATADDR_ANYNODE))
108			goto found;
109
110		/* XXXX.0 -- we got a request for this router. make sure
111		 * that the node is appropriately set. */
112		if (to->sat_addr.s_node == ATADDR_ANYNODE &&
113		    to->sat_addr.s_net != ATADDR_ANYNET &&
114		    atif->address.s_node == at->src_node) {
115			to->sat_addr.s_node = atif->address.s_node;
116			goto found;
117		}
118	}
119	s = NULL;
120found:
121	read_unlock_bh(&atalk_sockets_lock);
122	return s;
123}
124
125/**
126 * atalk_find_or_insert_socket - Try to find a socket matching ADDR
127 * @sk: socket to insert in the list if it is not there already
128 * @sat: address to search for
129 *
130 * Try to find a socket matching ADDR in the socket list, if found then return
131 * it. If not, insert SK into the socket list.
132 *
133 * This entire operation must execute atomically.
134 */
135static struct sock *atalk_find_or_insert_socket(struct sock *sk,
136						struct sockaddr_at *sat)
137{
138	struct sock *s;
139	struct atalk_sock *at;
140
141	write_lock_bh(&atalk_sockets_lock);
142	sk_for_each(s, &atalk_sockets) {
143		at = at_sk(s);
144
145		if (at->src_net == sat->sat_addr.s_net &&
146		    at->src_node == sat->sat_addr.s_node &&
147		    at->src_port == sat->sat_port)
148			goto found;
149	}
150	s = NULL;
151	__atalk_insert_socket(sk); /* Wheee, it's free, assign and insert. */
152found:
153	write_unlock_bh(&atalk_sockets_lock);
154	return s;
155}
156
157static void atalk_destroy_timer(struct timer_list *t)
158{
159	struct sock *sk = from_timer(sk, t, sk_timer);
160
161	if (sk_has_allocations(sk)) {
162		sk->sk_timer.expires = jiffies + SOCK_DESTROY_TIME;
163		add_timer(&sk->sk_timer);
164	} else
165		sock_put(sk);
166}
167
168static inline void atalk_destroy_socket(struct sock *sk)
169{
170	atalk_remove_socket(sk);
171	skb_queue_purge(&sk->sk_receive_queue);
172
173	if (sk_has_allocations(sk)) {
174		timer_setup(&sk->sk_timer, atalk_destroy_timer, 0);
175		sk->sk_timer.expires	= jiffies + SOCK_DESTROY_TIME;
176		add_timer(&sk->sk_timer);
177	} else
178		sock_put(sk);
179}
180
181/**************************************************************************\
182*                                                                          *
183* Routing tables for the AppleTalk socket layer.                           *
184*                                                                          *
185\**************************************************************************/
186
187/* Anti-deadlock ordering is atalk_routes_lock --> iface_lock -DaveM */
188struct atalk_route *atalk_routes;
189DEFINE_RWLOCK(atalk_routes_lock);
190
191struct atalk_iface *atalk_interfaces;
192DEFINE_RWLOCK(atalk_interfaces_lock);
193
194/* For probing devices or in a routerless network */
195struct atalk_route atrtr_default;
196
197/* AppleTalk interface control */
198/*
199 * Drop a device. Doesn't drop any of its routes - that is the caller's
200 * problem. Called when we down the interface or delete the address.
201 */
202static void atif_drop_device(struct net_device *dev)
203{
204	struct atalk_iface **iface = &atalk_interfaces;
205	struct atalk_iface *tmp;
206
207	write_lock_bh(&atalk_interfaces_lock);
208	while ((tmp = *iface) != NULL) {
209		if (tmp->dev == dev) {
210			*iface = tmp->next;
211			dev_put(dev);
212			kfree(tmp);
213			dev->atalk_ptr = NULL;
214		} else
215			iface = &tmp->next;
216	}
217	write_unlock_bh(&atalk_interfaces_lock);
218}
219
220static struct atalk_iface *atif_add_device(struct net_device *dev,
221					   struct atalk_addr *sa)
222{
223	struct atalk_iface *iface = kzalloc(sizeof(*iface), GFP_KERNEL);
224
225	if (!iface)
226		goto out;
227
228	dev_hold(dev);
229	iface->dev = dev;
230	dev->atalk_ptr = iface;
231	iface->address = *sa;
232	iface->status = 0;
233
234	write_lock_bh(&atalk_interfaces_lock);
235	iface->next = atalk_interfaces;
236	atalk_interfaces = iface;
237	write_unlock_bh(&atalk_interfaces_lock);
238out:
239	return iface;
240}
241
242/* Perform phase 2 AARP probing on our tentative address */
243static int atif_probe_device(struct atalk_iface *atif)
244{
245	int netrange = ntohs(atif->nets.nr_lastnet) -
246			ntohs(atif->nets.nr_firstnet) + 1;
247	int probe_net = ntohs(atif->address.s_net);
248	int probe_node = atif->address.s_node;
249	int netct, nodect;
250
251	/* Offset the network we start probing with */
252	if (probe_net == ATADDR_ANYNET) {
253		probe_net = ntohs(atif->nets.nr_firstnet);
254		if (netrange)
255			probe_net += jiffies % netrange;
256	}
257	if (probe_node == ATADDR_ANYNODE)
258		probe_node = jiffies & 0xFF;
259
260	/* Scan the networks */
261	atif->status |= ATIF_PROBE;
262	for (netct = 0; netct <= netrange; netct++) {
263		/* Sweep the available nodes from a given start */
264		atif->address.s_net = htons(probe_net);
265		for (nodect = 0; nodect < 256; nodect++) {
266			atif->address.s_node = (nodect + probe_node) & 0xFF;
267			if (atif->address.s_node > 0 &&
268			    atif->address.s_node < 254) {
269				/* Probe a proposed address */
270				aarp_probe_network(atif);
271
272				if (!(atif->status & ATIF_PROBE_FAIL)) {
273					atif->status &= ~ATIF_PROBE;
274					return 0;
275				}
276			}
277			atif->status &= ~ATIF_PROBE_FAIL;
278		}
279		probe_net++;
280		if (probe_net > ntohs(atif->nets.nr_lastnet))
281			probe_net = ntohs(atif->nets.nr_firstnet);
282	}
283	atif->status &= ~ATIF_PROBE;
284
285	return -EADDRINUSE;	/* Network is full... */
286}
287
288
289/* Perform AARP probing for a proxy address */
290static int atif_proxy_probe_device(struct atalk_iface *atif,
291				   struct atalk_addr *proxy_addr)
292{
293	int netrange = ntohs(atif->nets.nr_lastnet) -
294			ntohs(atif->nets.nr_firstnet) + 1;
295	/* we probe the interface's network */
296	int probe_net = ntohs(atif->address.s_net);
297	int probe_node = ATADDR_ANYNODE;	    /* we'll take anything */
298	int netct, nodect;
299
300	/* Offset the network we start probing with */
301	if (probe_net == ATADDR_ANYNET) {
302		probe_net = ntohs(atif->nets.nr_firstnet);
303		if (netrange)
304			probe_net += jiffies % netrange;
305	}
306
307	if (probe_node == ATADDR_ANYNODE)
308		probe_node = jiffies & 0xFF;
309
310	/* Scan the networks */
311	for (netct = 0; netct <= netrange; netct++) {
312		/* Sweep the available nodes from a given start */
313		proxy_addr->s_net = htons(probe_net);
314		for (nodect = 0; nodect < 256; nodect++) {
315			proxy_addr->s_node = (nodect + probe_node) & 0xFF;
316			if (proxy_addr->s_node > 0 &&
317			    proxy_addr->s_node < 254) {
318				/* Tell AARP to probe a proposed address */
319				int ret = aarp_proxy_probe_network(atif,
320								    proxy_addr);
321
322				if (ret != -EADDRINUSE)
323					return ret;
324			}
325		}
326		probe_net++;
327		if (probe_net > ntohs(atif->nets.nr_lastnet))
328			probe_net = ntohs(atif->nets.nr_firstnet);
329	}
330
331	return -EADDRINUSE;	/* Network is full... */
332}
333
334
335struct atalk_addr *atalk_find_dev_addr(struct net_device *dev)
336{
337	struct atalk_iface *iface = dev->atalk_ptr;
338	return iface ? &iface->address : NULL;
339}
340
341static struct atalk_addr *atalk_find_primary(void)
342{
343	struct atalk_iface *fiface = NULL;
344	struct atalk_addr *retval;
345	struct atalk_iface *iface;
346
347	/*
348	 * Return a point-to-point interface only if
349	 * there is no non-ptp interface available.
350	 */
351	read_lock_bh(&atalk_interfaces_lock);
352	for (iface = atalk_interfaces; iface; iface = iface->next) {
353		if (!fiface && !(iface->dev->flags & IFF_LOOPBACK))
354			fiface = iface;
355		if (!(iface->dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
356			retval = &iface->address;
357			goto out;
358		}
359	}
360
361	if (fiface)
362		retval = &fiface->address;
363	else if (atalk_interfaces)
364		retval = &atalk_interfaces->address;
365	else
366		retval = NULL;
367out:
368	read_unlock_bh(&atalk_interfaces_lock);
369	return retval;
370}
371
372/*
373 * Find a match for 'any network' - ie any of our interfaces with that
374 * node number will do just nicely.
375 */
376static struct atalk_iface *atalk_find_anynet(int node, struct net_device *dev)
377{
378	struct atalk_iface *iface = dev->atalk_ptr;
379
380	if (!iface || iface->status & ATIF_PROBE)
381		goto out_err;
382
383	if (node != ATADDR_BCAST &&
384	    iface->address.s_node != node &&
385	    node != ATADDR_ANYNODE)
386		goto out_err;
387out:
388	return iface;
389out_err:
390	iface = NULL;
391	goto out;
392}
393
394/* Find a match for a specific network:node pair */
395static struct atalk_iface *atalk_find_interface(__be16 net, int node)
396{
397	struct atalk_iface *iface;
398
399	read_lock_bh(&atalk_interfaces_lock);
400	for (iface = atalk_interfaces; iface; iface = iface->next) {
401		if ((node == ATADDR_BCAST ||
402		     node == ATADDR_ANYNODE ||
403		     iface->address.s_node == node) &&
404		    iface->address.s_net == net &&
405		    !(iface->status & ATIF_PROBE))
406			break;
407
408		/* XXXX.0 -- net.0 returns the iface associated with net */
409		if (node == ATADDR_ANYNODE && net != ATADDR_ANYNET &&
410		    ntohs(iface->nets.nr_firstnet) <= ntohs(net) &&
411		    ntohs(net) <= ntohs(iface->nets.nr_lastnet))
412			break;
413	}
414	read_unlock_bh(&atalk_interfaces_lock);
415	return iface;
416}
417
418
419/*
420 * Find a route for an AppleTalk packet. This ought to get cached in
421 * the socket (later on...). We know about host routes and the fact
422 * that a route must be direct to broadcast.
423 */
424static struct atalk_route *atrtr_find(struct atalk_addr *target)
425{
426	/*
427	 * we must search through all routes unless we find a
428	 * host route, because some host routes might overlap
429	 * network routes
430	 */
431	struct atalk_route *net_route = NULL;
432	struct atalk_route *r;
433
434	read_lock_bh(&atalk_routes_lock);
435	for (r = atalk_routes; r; r = r->next) {
436		if (!(r->flags & RTF_UP))
437			continue;
438
439		if (r->target.s_net == target->s_net) {
440			if (r->flags & RTF_HOST) {
441				/*
442				 * if this host route is for the target,
443				 * the we're done
444				 */
445				if (r->target.s_node == target->s_node)
446					goto out;
447			} else
448				/*
449				 * this route will work if there isn't a
450				 * direct host route, so cache it
451				 */
452				net_route = r;
453		}
454	}
455
456	/*
457	 * if we found a network route but not a direct host
458	 * route, then return it
459	 */
460	if (net_route)
461		r = net_route;
462	else if (atrtr_default.dev)
463		r = &atrtr_default;
464	else /* No route can be found */
465		r = NULL;
466out:
467	read_unlock_bh(&atalk_routes_lock);
468	return r;
469}
470
471
472/*
473 * Given an AppleTalk network, find the device to use. This can be
474 * a simple lookup.
475 */
476struct net_device *atrtr_get_dev(struct atalk_addr *sa)
477{
478	struct atalk_route *atr = atrtr_find(sa);
479	return atr ? atr->dev : NULL;
480}
481
482/* Set up a default router */
483static void atrtr_set_default(struct net_device *dev)
484{
485	atrtr_default.dev	     = dev;
486	atrtr_default.flags	     = RTF_UP;
487	atrtr_default.gateway.s_net  = htons(0);
488	atrtr_default.gateway.s_node = 0;
489}
490
491/*
492 * Add a router. Basically make sure it looks valid and stuff the
493 * entry in the list. While it uses netranges we always set them to one
494 * entry to work like netatalk.
495 */
496static int atrtr_create(struct rtentry *r, struct net_device *devhint)
497{
498	struct sockaddr_at *ta = (struct sockaddr_at *)&r->rt_dst;
499	struct sockaddr_at *ga = (struct sockaddr_at *)&r->rt_gateway;
500	struct atalk_route *rt;
501	struct atalk_iface *iface, *riface;
502	int retval = -EINVAL;
503
504	/*
505	 * Fixme: Raise/Lower a routing change semaphore for these
506	 * operations.
507	 */
508
509	/* Validate the request */
510	if (ta->sat_family != AF_APPLETALK ||
511	    (!devhint && ga->sat_family != AF_APPLETALK))
512		goto out;
513
514	/* Now walk the routing table and make our decisions */
515	write_lock_bh(&atalk_routes_lock);
516	for (rt = atalk_routes; rt; rt = rt->next) {
517		if (r->rt_flags != rt->flags)
518			continue;
519
520		if (ta->sat_addr.s_net == rt->target.s_net) {
521			if (!(rt->flags & RTF_HOST))
522				break;
523			if (ta->sat_addr.s_node == rt->target.s_node)
524				break;
525		}
526	}
527
528	if (!devhint) {
529		riface = NULL;
530
531		read_lock_bh(&atalk_interfaces_lock);
532		for (iface = atalk_interfaces; iface; iface = iface->next) {
533			if (!riface &&
534			    ntohs(ga->sat_addr.s_net) >=
535					ntohs(iface->nets.nr_firstnet) &&
536			    ntohs(ga->sat_addr.s_net) <=
537					ntohs(iface->nets.nr_lastnet))
538				riface = iface;
539
540			if (ga->sat_addr.s_net == iface->address.s_net &&
541			    ga->sat_addr.s_node == iface->address.s_node)
542				riface = iface;
543		}
544		read_unlock_bh(&atalk_interfaces_lock);
545
546		retval = -ENETUNREACH;
547		if (!riface)
548			goto out_unlock;
549
550		devhint = riface->dev;
551	}
552
553	if (!rt) {
554		rt = kzalloc(sizeof(*rt), GFP_ATOMIC);
555
556		retval = -ENOBUFS;
557		if (!rt)
558			goto out_unlock;
559
560		rt->next = atalk_routes;
561		atalk_routes = rt;
562	}
563
564	/* Fill in the routing entry */
565	rt->target  = ta->sat_addr;
566	dev_hold(devhint);
567	rt->dev     = devhint;
568	rt->flags   = r->rt_flags;
569	rt->gateway = ga->sat_addr;
570
571	retval = 0;
572out_unlock:
573	write_unlock_bh(&atalk_routes_lock);
574out:
575	return retval;
576}
577
578/* Delete a route. Find it and discard it */
579static int atrtr_delete(struct atalk_addr *addr)
580{
581	struct atalk_route **r = &atalk_routes;
582	int retval = 0;
583	struct atalk_route *tmp;
584
585	write_lock_bh(&atalk_routes_lock);
586	while ((tmp = *r) != NULL) {
587		if (tmp->target.s_net == addr->s_net &&
588		    (!(tmp->flags&RTF_GATEWAY) ||
589		     tmp->target.s_node == addr->s_node)) {
590			*r = tmp->next;
591			dev_put(tmp->dev);
592			kfree(tmp);
593			goto out;
594		}
595		r = &tmp->next;
596	}
597	retval = -ENOENT;
598out:
599	write_unlock_bh(&atalk_routes_lock);
600	return retval;
601}
602
603/*
604 * Called when a device is downed. Just throw away any routes
605 * via it.
606 */
607static void atrtr_device_down(struct net_device *dev)
608{
609	struct atalk_route **r = &atalk_routes;
610	struct atalk_route *tmp;
611
612	write_lock_bh(&atalk_routes_lock);
613	while ((tmp = *r) != NULL) {
614		if (tmp->dev == dev) {
615			*r = tmp->next;
616			dev_put(dev);
617			kfree(tmp);
618		} else
619			r = &tmp->next;
620	}
621	write_unlock_bh(&atalk_routes_lock);
622
623	if (atrtr_default.dev == dev)
624		atrtr_set_default(NULL);
625}
626
627/* Actually down the interface */
628static inline void atalk_dev_down(struct net_device *dev)
629{
630	atrtr_device_down(dev);	/* Remove all routes for the device */
631	aarp_device_down(dev);	/* Remove AARP entries for the device */
632	atif_drop_device(dev);	/* Remove the device */
633}
634
635/*
636 * A device event has occurred. Watch for devices going down and
637 * delete our use of them (iface and route).
638 */
639static int ddp_device_event(struct notifier_block *this, unsigned long event,
640			    void *ptr)
641{
642	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
643
644	if (!net_eq(dev_net(dev), &init_net))
645		return NOTIFY_DONE;
646
647	if (event == NETDEV_DOWN)
648		/* Discard any use of this */
649		atalk_dev_down(dev);
650
651	return NOTIFY_DONE;
652}
653
654/* ioctl calls. Shouldn't even need touching */
655/* Device configuration ioctl calls */
656static int atif_ioctl(int cmd, void __user *arg)
657{
658	static char aarp_mcast[6] = { 0x09, 0x00, 0x00, 0xFF, 0xFF, 0xFF };
659	struct ifreq atreq;
660	struct atalk_netrange *nr;
661	struct sockaddr_at *sa;
662	struct net_device *dev;
663	struct atalk_iface *atif;
664	int ct;
665	int limit;
666	struct rtentry rtdef;
667	int add_route;
668
669	if (copy_from_user(&atreq, arg, sizeof(atreq)))
670		return -EFAULT;
671
672	dev = __dev_get_by_name(&init_net, atreq.ifr_name);
673	if (!dev)
674		return -ENODEV;
675
676	sa = (struct sockaddr_at *)&atreq.ifr_addr;
677	atif = atalk_find_dev(dev);
678
679	switch (cmd) {
680	case SIOCSIFADDR:
681		if (!capable(CAP_NET_ADMIN))
682			return -EPERM;
683		if (sa->sat_family != AF_APPLETALK)
684			return -EINVAL;
685		if (dev->type != ARPHRD_ETHER &&
686		    dev->type != ARPHRD_LOOPBACK &&
687		    dev->type != ARPHRD_LOCALTLK &&
688		    dev->type != ARPHRD_PPP)
689			return -EPROTONOSUPPORT;
690
691		nr = (struct atalk_netrange *)&sa->sat_zero[0];
692		add_route = 1;
693
694		/*
695		 * if this is a point-to-point iface, and we already
696		 * have an iface for this AppleTalk address, then we
697		 * should not add a route
698		 */
699		if ((dev->flags & IFF_POINTOPOINT) &&
700		    atalk_find_interface(sa->sat_addr.s_net,
701					 sa->sat_addr.s_node)) {
702			printk(KERN_DEBUG "AppleTalk: point-to-point "
703			       "interface added with "
704			       "existing address\n");
705			add_route = 0;
706		}
707
708		/*
709		 * Phase 1 is fine on LocalTalk but we don't do
710		 * EtherTalk phase 1. Anyone wanting to add it go ahead.
711		 */
712		if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
713			return -EPROTONOSUPPORT;
714		if (sa->sat_addr.s_node == ATADDR_BCAST ||
715		    sa->sat_addr.s_node == 254)
716			return -EINVAL;
717		if (atif) {
718			/* Already setting address */
719			if (atif->status & ATIF_PROBE)
720				return -EBUSY;
721
722			atif->address.s_net  = sa->sat_addr.s_net;
723			atif->address.s_node = sa->sat_addr.s_node;
724			atrtr_device_down(dev);	/* Flush old routes */
725		} else {
726			atif = atif_add_device(dev, &sa->sat_addr);
727			if (!atif)
728				return -ENOMEM;
729		}
730		atif->nets = *nr;
731
732		/*
733		 * Check if the chosen address is used. If so we
734		 * error and atalkd will try another.
735		 */
736
737		if (!(dev->flags & IFF_LOOPBACK) &&
738		    !(dev->flags & IFF_POINTOPOINT) &&
739		    atif_probe_device(atif) < 0) {
740			atif_drop_device(dev);
741			return -EADDRINUSE;
742		}
743
744		/* Hey it worked - add the direct routes */
745		sa = (struct sockaddr_at *)&rtdef.rt_gateway;
746		sa->sat_family = AF_APPLETALK;
747		sa->sat_addr.s_net  = atif->address.s_net;
748		sa->sat_addr.s_node = atif->address.s_node;
749		sa = (struct sockaddr_at *)&rtdef.rt_dst;
750		rtdef.rt_flags = RTF_UP;
751		sa->sat_family = AF_APPLETALK;
752		sa->sat_addr.s_node = ATADDR_ANYNODE;
753		if (dev->flags & IFF_LOOPBACK ||
754		    dev->flags & IFF_POINTOPOINT)
755			rtdef.rt_flags |= RTF_HOST;
756
757		/* Routerless initial state */
758		if (nr->nr_firstnet == htons(0) &&
759		    nr->nr_lastnet == htons(0xFFFE)) {
760			sa->sat_addr.s_net = atif->address.s_net;
761			atrtr_create(&rtdef, dev);
762			atrtr_set_default(dev);
763		} else {
764			limit = ntohs(nr->nr_lastnet);
765			if (limit - ntohs(nr->nr_firstnet) > 4096) {
766				printk(KERN_WARNING "Too many routes/"
767				       "iface.\n");
768				return -EINVAL;
769			}
770			if (add_route)
771				for (ct = ntohs(nr->nr_firstnet);
772				     ct <= limit; ct++) {
773					sa->sat_addr.s_net = htons(ct);
774					atrtr_create(&rtdef, dev);
775				}
776		}
777		dev_mc_add_global(dev, aarp_mcast);
778		return 0;
779
780	case SIOCGIFADDR:
781		if (!atif)
782			return -EADDRNOTAVAIL;
783
784		sa->sat_family = AF_APPLETALK;
785		sa->sat_addr = atif->address;
786		break;
787
788	case SIOCGIFBRDADDR:
789		if (!atif)
790			return -EADDRNOTAVAIL;
791
792		sa->sat_family = AF_APPLETALK;
793		sa->sat_addr.s_net = atif->address.s_net;
794		sa->sat_addr.s_node = ATADDR_BCAST;
795		break;
796
797	case SIOCATALKDIFADDR:
798	case SIOCDIFADDR:
799		if (!capable(CAP_NET_ADMIN))
800			return -EPERM;
801		if (sa->sat_family != AF_APPLETALK)
802			return -EINVAL;
803		atalk_dev_down(dev);
804		break;
805
806	case SIOCSARP:
807		if (!capable(CAP_NET_ADMIN))
808			return -EPERM;
809		if (sa->sat_family != AF_APPLETALK)
810			return -EINVAL;
811		/*
812		 * for now, we only support proxy AARP on ELAP;
813		 * we should be able to do it for LocalTalk, too.
814		 */
815		if (dev->type != ARPHRD_ETHER)
816			return -EPROTONOSUPPORT;
817
818		/*
819		 * atif points to the current interface on this network;
820		 * we aren't concerned about its current status (at
821		 * least for now), but it has all the settings about
822		 * the network we're going to probe. Consequently, it
823		 * must exist.
824		 */
825		if (!atif)
826			return -EADDRNOTAVAIL;
827
828		nr = (struct atalk_netrange *)&(atif->nets);
829		/*
830		 * Phase 1 is fine on Localtalk but we don't do
831		 * Ethertalk phase 1. Anyone wanting to add it go ahead.
832		 */
833		if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
834			return -EPROTONOSUPPORT;
835
836		if (sa->sat_addr.s_node == ATADDR_BCAST ||
837		    sa->sat_addr.s_node == 254)
838			return -EINVAL;
839
840		/*
841		 * Check if the chosen address is used. If so we
842		 * error and ATCP will try another.
843		 */
844		if (atif_proxy_probe_device(atif, &(sa->sat_addr)) < 0)
845			return -EADDRINUSE;
846
847		/*
848		 * We now have an address on the local network, and
849		 * the AARP code will defend it for us until we take it
850		 * down. We don't set up any routes right now, because
851		 * ATCP will install them manually via SIOCADDRT.
852		 */
853		break;
854
855	case SIOCDARP:
856		if (!capable(CAP_NET_ADMIN))
857			return -EPERM;
858		if (sa->sat_family != AF_APPLETALK)
859			return -EINVAL;
860		if (!atif)
861			return -EADDRNOTAVAIL;
862
863		/* give to aarp module to remove proxy entry */
864		aarp_proxy_remove(atif->dev, &(sa->sat_addr));
865		return 0;
866	}
867
868	return copy_to_user(arg, &atreq, sizeof(atreq)) ? -EFAULT : 0;
869}
870
871static int atrtr_ioctl_addrt(struct rtentry *rt)
872{
873	struct net_device *dev = NULL;
874
875	if (rt->rt_dev) {
876		char name[IFNAMSIZ];
877
878		if (copy_from_user(name, rt->rt_dev, IFNAMSIZ-1))
879			return -EFAULT;
880		name[IFNAMSIZ-1] = '\0';
881
882		dev = __dev_get_by_name(&init_net, name);
883		if (!dev)
884			return -ENODEV;
885	}
886	return atrtr_create(rt, dev);
887}
888
889/* Routing ioctl() calls */
890static int atrtr_ioctl(unsigned int cmd, void __user *arg)
891{
892	struct rtentry rt;
893
894	if (copy_from_user(&rt, arg, sizeof(rt)))
895		return -EFAULT;
896
897	switch (cmd) {
898	case SIOCDELRT:
899		if (rt.rt_dst.sa_family != AF_APPLETALK)
900			return -EINVAL;
901		return atrtr_delete(&((struct sockaddr_at *)
902				      &rt.rt_dst)->sat_addr);
903
904	case SIOCADDRT:
905		return atrtr_ioctl_addrt(&rt);
906	}
907	return -EINVAL;
908}
909
910/**************************************************************************\
911*                                                                          *
912* Handling for system calls applied via the various interfaces to an       *
913* AppleTalk socket object.                                                 *
914*                                                                          *
915\**************************************************************************/
916
917/*
918 * Checksum: This is 'optional'. It's quite likely also a good
919 * candidate for assembler hackery 8)
920 */
921static unsigned long atalk_sum_partial(const unsigned char *data,
922				       int len, unsigned long sum)
923{
924	/* This ought to be unwrapped neatly. I'll trust gcc for now */
925	while (len--) {
926		sum += *data++;
927		sum = rol16(sum, 1);
928	}
929	return sum;
930}
931
932/*  Checksum skb data --  similar to skb_checksum  */
933static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
934				   int len, unsigned long sum)
935{
936	int start = skb_headlen(skb);
937	struct sk_buff *frag_iter;
938	int i, copy;
939
940	/* checksum stuff in header space */
941	if ((copy = start - offset) > 0) {
942		if (copy > len)
943			copy = len;
944		sum = atalk_sum_partial(skb->data + offset, copy, sum);
945		if ((len -= copy) == 0)
946			return sum;
947
948		offset += copy;
949	}
950
951	/* checksum stuff in frags */
952	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
953		int end;
954		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
955		WARN_ON(start > offset + len);
956
957		end = start + skb_frag_size(frag);
958		if ((copy = end - offset) > 0) {
959			u8 *vaddr;
960
961			if (copy > len)
962				copy = len;
963			vaddr = kmap_atomic(skb_frag_page(frag));
964			sum = atalk_sum_partial(vaddr + skb_frag_off(frag) +
965						offset - start, copy, sum);
966			kunmap_atomic(vaddr);
967
968			if (!(len -= copy))
969				return sum;
970			offset += copy;
971		}
972		start = end;
973	}
974
975	skb_walk_frags(skb, frag_iter) {
976		int end;
977
978		WARN_ON(start > offset + len);
979
980		end = start + frag_iter->len;
981		if ((copy = end - offset) > 0) {
982			if (copy > len)
983				copy = len;
984			sum = atalk_sum_skb(frag_iter, offset - start,
985					    copy, sum);
986			if ((len -= copy) == 0)
987				return sum;
988			offset += copy;
989		}
990		start = end;
991	}
992
993	BUG_ON(len > 0);
994
995	return sum;
996}
997
998static __be16 atalk_checksum(const struct sk_buff *skb, int len)
999{
1000	unsigned long sum;
1001
1002	/* skip header 4 bytes */
1003	sum = atalk_sum_skb(skb, 4, len-4, 0);
1004
1005	/* Use 0xFFFF for 0. 0 itself means none */
1006	return sum ? htons((unsigned short)sum) : htons(0xFFFF);
1007}
1008
1009static struct proto ddp_proto = {
1010	.name	  = "DDP",
1011	.owner	  = THIS_MODULE,
1012	.obj_size = sizeof(struct atalk_sock),
1013};
1014
1015/*
1016 * Create a socket. Initialise the socket, blank the addresses
1017 * set the state.
1018 */
1019static int atalk_create(struct net *net, struct socket *sock, int protocol,
1020			int kern)
1021{
1022	struct sock *sk;
1023	int rc = -ESOCKTNOSUPPORT;
1024
1025	if (!net_eq(net, &init_net))
1026		return -EAFNOSUPPORT;
1027
1028	/*
1029	 * We permit SOCK_DGRAM and RAW is an extension. It is trivial to do
1030	 * and gives you the full ELAP frame. Should be handy for CAP 8)
1031	 */
1032	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
1033		goto out;
1034
1035	rc = -EPERM;
1036	if (sock->type == SOCK_RAW && !kern && !capable(CAP_NET_RAW))
1037		goto out;
1038
1039	rc = -ENOMEM;
1040	sk = sk_alloc(net, PF_APPLETALK, GFP_KERNEL, &ddp_proto, kern);
1041	if (!sk)
1042		goto out;
1043	rc = 0;
1044	sock->ops = &atalk_dgram_ops;
1045	sock_init_data(sock, sk);
1046
1047	/* Checksums on by default */
1048	sock_set_flag(sk, SOCK_ZAPPED);
1049out:
1050	return rc;
1051}
1052
1053/* Free a socket. No work needed */
1054static int atalk_release(struct socket *sock)
1055{
1056	struct sock *sk = sock->sk;
1057
1058	if (sk) {
1059		sock_hold(sk);
1060		lock_sock(sk);
1061
1062		sock_orphan(sk);
1063		sock->sk = NULL;
1064		atalk_destroy_socket(sk);
1065
1066		release_sock(sk);
1067		sock_put(sk);
1068	}
1069	return 0;
1070}
1071
1072/**
1073 * atalk_pick_and_bind_port - Pick a source port when one is not given
1074 * @sk: socket to insert into the tables
1075 * @sat: address to search for
1076 *
1077 * Pick a source port when one is not given. If we can find a suitable free
1078 * one, we insert the socket into the tables using it.
1079 *
1080 * This whole operation must be atomic.
1081 */
1082static int atalk_pick_and_bind_port(struct sock *sk, struct sockaddr_at *sat)
1083{
1084	int retval;
1085
1086	write_lock_bh(&atalk_sockets_lock);
1087
1088	for (sat->sat_port = ATPORT_RESERVED;
1089	     sat->sat_port < ATPORT_LAST;
1090	     sat->sat_port++) {
1091		struct sock *s;
1092
1093		sk_for_each(s, &atalk_sockets) {
1094			struct atalk_sock *at = at_sk(s);
1095
1096			if (at->src_net == sat->sat_addr.s_net &&
1097			    at->src_node == sat->sat_addr.s_node &&
1098			    at->src_port == sat->sat_port)
1099				goto try_next_port;
1100		}
1101
1102		/* Wheee, it's free, assign and insert. */
1103		__atalk_insert_socket(sk);
1104		at_sk(sk)->src_port = sat->sat_port;
1105		retval = 0;
1106		goto out;
1107
1108try_next_port:;
1109	}
1110
1111	retval = -EBUSY;
1112out:
1113	write_unlock_bh(&atalk_sockets_lock);
1114	return retval;
1115}
1116
1117static int atalk_autobind(struct sock *sk)
1118{
1119	struct atalk_sock *at = at_sk(sk);
1120	struct sockaddr_at sat;
1121	struct atalk_addr *ap = atalk_find_primary();
1122	int n = -EADDRNOTAVAIL;
1123
1124	if (!ap || ap->s_net == htons(ATADDR_ANYNET))
1125		goto out;
1126
1127	at->src_net  = sat.sat_addr.s_net  = ap->s_net;
1128	at->src_node = sat.sat_addr.s_node = ap->s_node;
1129
1130	n = atalk_pick_and_bind_port(sk, &sat);
1131	if (!n)
1132		sock_reset_flag(sk, SOCK_ZAPPED);
1133out:
1134	return n;
1135}
1136
1137/* Set the address 'our end' of the connection */
1138static int atalk_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1139{
1140	struct sockaddr_at *addr = (struct sockaddr_at *)uaddr;
1141	struct sock *sk = sock->sk;
1142	struct atalk_sock *at = at_sk(sk);
1143	int err;
1144
1145	if (!sock_flag(sk, SOCK_ZAPPED) ||
1146	    addr_len != sizeof(struct sockaddr_at))
1147		return -EINVAL;
1148
1149	if (addr->sat_family != AF_APPLETALK)
1150		return -EAFNOSUPPORT;
1151
1152	lock_sock(sk);
1153	if (addr->sat_addr.s_net == htons(ATADDR_ANYNET)) {
1154		struct atalk_addr *ap = atalk_find_primary();
1155
1156		err = -EADDRNOTAVAIL;
1157		if (!ap)
1158			goto out;
1159
1160		at->src_net  = addr->sat_addr.s_net = ap->s_net;
1161		at->src_node = addr->sat_addr.s_node = ap->s_node;
1162	} else {
1163		err = -EADDRNOTAVAIL;
1164		if (!atalk_find_interface(addr->sat_addr.s_net,
1165					  addr->sat_addr.s_node))
1166			goto out;
1167
1168		at->src_net  = addr->sat_addr.s_net;
1169		at->src_node = addr->sat_addr.s_node;
1170	}
1171
1172	if (addr->sat_port == ATADDR_ANYPORT) {
1173		err = atalk_pick_and_bind_port(sk, addr);
1174
1175		if (err < 0)
1176			goto out;
1177	} else {
1178		at->src_port = addr->sat_port;
1179
1180		err = -EADDRINUSE;
1181		if (atalk_find_or_insert_socket(sk, addr))
1182			goto out;
1183	}
1184
1185	sock_reset_flag(sk, SOCK_ZAPPED);
1186	err = 0;
1187out:
1188	release_sock(sk);
1189	return err;
1190}
1191
1192/* Set the address we talk to */
1193static int atalk_connect(struct socket *sock, struct sockaddr *uaddr,
1194			 int addr_len, int flags)
1195{
1196	struct sock *sk = sock->sk;
1197	struct atalk_sock *at = at_sk(sk);
1198	struct sockaddr_at *addr;
1199	int err;
1200
1201	sk->sk_state   = TCP_CLOSE;
1202	sock->state = SS_UNCONNECTED;
1203
1204	if (addr_len != sizeof(*addr))
1205		return -EINVAL;
1206
1207	addr = (struct sockaddr_at *)uaddr;
1208
1209	if (addr->sat_family != AF_APPLETALK)
1210		return -EAFNOSUPPORT;
1211
1212	if (addr->sat_addr.s_node == ATADDR_BCAST &&
1213	    !sock_flag(sk, SOCK_BROADCAST)) {
1214#if 1
1215		pr_warn("atalk_connect: %s is broken and did not set SO_BROADCAST.\n",
1216			current->comm);
1217#else
1218		return -EACCES;
1219#endif
1220	}
1221
1222	lock_sock(sk);
1223	err = -EBUSY;
1224	if (sock_flag(sk, SOCK_ZAPPED))
1225		if (atalk_autobind(sk) < 0)
1226			goto out;
1227
1228	err = -ENETUNREACH;
1229	if (!atrtr_get_dev(&addr->sat_addr))
1230		goto out;
1231
1232	at->dest_port = addr->sat_port;
1233	at->dest_net  = addr->sat_addr.s_net;
1234	at->dest_node = addr->sat_addr.s_node;
1235
1236	sock->state  = SS_CONNECTED;
1237	sk->sk_state = TCP_ESTABLISHED;
1238	err = 0;
1239out:
1240	release_sock(sk);
1241	return err;
1242}
1243
1244/*
1245 * Find the name of an AppleTalk socket. Just copy the right
1246 * fields into the sockaddr.
1247 */
1248static int atalk_getname(struct socket *sock, struct sockaddr *uaddr,
1249			 int peer)
1250{
1251	struct sockaddr_at sat;
1252	struct sock *sk = sock->sk;
1253	struct atalk_sock *at = at_sk(sk);
1254	int err;
1255
1256	lock_sock(sk);
1257	err = -ENOBUFS;
1258	if (sock_flag(sk, SOCK_ZAPPED))
1259		if (atalk_autobind(sk) < 0)
1260			goto out;
1261
1262	memset(&sat, 0, sizeof(sat));
1263
1264	if (peer) {
1265		err = -ENOTCONN;
1266		if (sk->sk_state != TCP_ESTABLISHED)
1267			goto out;
1268
1269		sat.sat_addr.s_net  = at->dest_net;
1270		sat.sat_addr.s_node = at->dest_node;
1271		sat.sat_port	    = at->dest_port;
1272	} else {
1273		sat.sat_addr.s_net  = at->src_net;
1274		sat.sat_addr.s_node = at->src_node;
1275		sat.sat_port	    = at->src_port;
1276	}
1277
1278	sat.sat_family = AF_APPLETALK;
1279	memcpy(uaddr, &sat, sizeof(sat));
1280	err = sizeof(struct sockaddr_at);
1281
1282out:
1283	release_sock(sk);
1284	return err;
1285}
1286
1287#if IS_ENABLED(CONFIG_IPDDP)
1288static __inline__ int is_ip_over_ddp(struct sk_buff *skb)
1289{
1290	return skb->data[12] == 22;
1291}
1292
1293static int handle_ip_over_ddp(struct sk_buff *skb)
1294{
1295	struct net_device *dev = __dev_get_by_name(&init_net, "ipddp0");
1296	struct net_device_stats *stats;
1297
1298	/* This needs to be able to handle ipddp"N" devices */
1299	if (!dev) {
1300		kfree_skb(skb);
1301		return NET_RX_DROP;
1302	}
1303
1304	skb->protocol = htons(ETH_P_IP);
1305	skb_pull(skb, 13);
1306	skb->dev   = dev;
1307	skb_reset_transport_header(skb);
1308
1309	stats = netdev_priv(dev);
1310	stats->rx_packets++;
1311	stats->rx_bytes += skb->len + 13;
1312	return netif_rx(skb);  /* Send the SKB up to a higher place. */
1313}
1314#else
1315/* make it easy for gcc to optimize this test out, i.e. kill the code */
1316#define is_ip_over_ddp(skb) 0
1317#define handle_ip_over_ddp(skb) 0
1318#endif
1319
1320static int atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
1321			      struct ddpehdr *ddp, __u16 len_hops, int origlen)
1322{
1323	struct atalk_route *rt;
1324	struct atalk_addr ta;
1325
1326	/*
1327	 * Don't route multicast, etc., packets, or packets sent to "this
1328	 * network"
1329	 */
1330	if (skb->pkt_type != PACKET_HOST || !ddp->deh_dnet) {
1331		/*
1332		 * FIXME:
1333		 *
1334		 * Can it ever happen that a packet is from a PPP iface and
1335		 * needs to be broadcast onto the default network?
1336		 */
1337		if (dev->type == ARPHRD_PPP)
1338			printk(KERN_DEBUG "AppleTalk: didn't forward broadcast "
1339					  "packet received from PPP iface\n");
1340		goto free_it;
1341	}
1342
1343	ta.s_net  = ddp->deh_dnet;
1344	ta.s_node = ddp->deh_dnode;
1345
1346	/* Route the packet */
1347	rt = atrtr_find(&ta);
1348	/* increment hops count */
1349	len_hops += 1 << 10;
1350	if (!rt || !(len_hops & (15 << 10)))
1351		goto free_it;
1352
1353	/* FIXME: use skb->cb to be able to use shared skbs */
1354
1355	/*
1356	 * Route goes through another gateway, so set the target to the
1357	 * gateway instead.
1358	 */
1359
1360	if (rt->flags & RTF_GATEWAY) {
1361		ta.s_net  = rt->gateway.s_net;
1362		ta.s_node = rt->gateway.s_node;
1363	}
1364
1365	/* Fix up skb->len field */
1366	skb_trim(skb, min_t(unsigned int, origlen,
1367			    (rt->dev->hard_header_len +
1368			     ddp_dl->header_length + (len_hops & 1023))));
1369
1370	/* FIXME: use skb->cb to be able to use shared skbs */
1371	ddp->deh_len_hops = htons(len_hops);
1372
1373	/*
1374	 * Send the buffer onwards
1375	 *
1376	 * Now we must always be careful. If it's come from LocalTalk to
1377	 * EtherTalk it might not fit
1378	 *
1379	 * Order matters here: If a packet has to be copied to make a new
1380	 * headroom (rare hopefully) then it won't need unsharing.
1381	 *
1382	 * Note. ddp-> becomes invalid at the realloc.
1383	 */
1384	if (skb_headroom(skb) < 22) {
1385		/* 22 bytes - 12 ether, 2 len, 3 802.2 5 snap */
1386		struct sk_buff *nskb = skb_realloc_headroom(skb, 32);
1387		kfree_skb(skb);
1388		skb = nskb;
1389	} else
1390		skb = skb_unshare(skb, GFP_ATOMIC);
1391
1392	/*
1393	 * If the buffer didn't vanish into the lack of space bitbucket we can
1394	 * send it.
1395	 */
1396	if (skb == NULL)
1397		goto drop;
1398
1399	if (aarp_send_ddp(rt->dev, skb, &ta, NULL) == NET_XMIT_DROP)
1400		return NET_RX_DROP;
1401	return NET_RX_SUCCESS;
1402free_it:
1403	kfree_skb(skb);
1404drop:
1405	return NET_RX_DROP;
1406}
1407
1408/**
1409 *	atalk_rcv - Receive a packet (in skb) from device dev
1410 *	@skb - packet received
1411 *	@dev - network device where the packet comes from
1412 *	@pt - packet type
1413 *
1414 *	Receive a packet (in skb) from device dev. This has come from the SNAP
1415 *	decoder, and on entry skb->transport_header is the DDP header, skb->len
1416 *	is the DDP header, skb->len is the DDP length. The physical headers
1417 *	have been extracted. PPP should probably pass frames marked as for this
1418 *	layer.  [ie ARPHRD_ETHERTALK]
1419 */
1420static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
1421		     struct packet_type *pt, struct net_device *orig_dev)
1422{
1423	struct ddpehdr *ddp;
1424	struct sock *sock;
1425	struct atalk_iface *atif;
1426	struct sockaddr_at tosat;
1427	int origlen;
1428	__u16 len_hops;
1429
1430	if (!net_eq(dev_net(dev), &init_net))
1431		goto drop;
1432
1433	/* Don't mangle buffer if shared */
1434	if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
1435		goto out;
1436
1437	/* Size check and make sure header is contiguous */
1438	if (!pskb_may_pull(skb, sizeof(*ddp)))
1439		goto drop;
1440
1441	ddp = ddp_hdr(skb);
1442
1443	len_hops = ntohs(ddp->deh_len_hops);
1444
1445	/* Trim buffer in case of stray trailing data */
1446	origlen = skb->len;
1447	skb_trim(skb, min_t(unsigned int, skb->len, len_hops & 1023));
1448
1449	/*
1450	 * Size check to see if ddp->deh_len was crap
1451	 * (Otherwise we'll detonate most spectacularly
1452	 * in the middle of atalk_checksum() or recvmsg()).
1453	 */
1454	if (skb->len < sizeof(*ddp) || skb->len < (len_hops & 1023)) {
1455		pr_debug("AppleTalk: dropping corrupted frame (deh_len=%u, "
1456			 "skb->len=%u)\n", len_hops & 1023, skb->len);
1457		goto drop;
1458	}
1459
1460	/*
1461	 * Any checksums. Note we don't do htons() on this == is assumed to be
1462	 * valid for net byte orders all over the networking code...
1463	 */
1464	if (ddp->deh_sum &&
1465	    atalk_checksum(skb, len_hops & 1023) != ddp->deh_sum)
1466		/* Not a valid AppleTalk frame - dustbin time */
1467		goto drop;
1468
1469	/* Check the packet is aimed at us */
1470	if (!ddp->deh_dnet)	/* Net 0 is 'this network' */
1471		atif = atalk_find_anynet(ddp->deh_dnode, dev);
1472	else
1473		atif = atalk_find_interface(ddp->deh_dnet, ddp->deh_dnode);
1474
1475	if (!atif) {
1476		/* Not ours, so we route the packet via the correct
1477		 * AppleTalk iface
1478		 */
1479		return atalk_route_packet(skb, dev, ddp, len_hops, origlen);
1480	}
1481
1482	/* if IP over DDP is not selected this code will be optimized out */
1483	if (is_ip_over_ddp(skb))
1484		return handle_ip_over_ddp(skb);
1485	/*
1486	 * Which socket - atalk_search_socket() looks for a *full match*
1487	 * of the <net, node, port> tuple.
1488	 */
1489	tosat.sat_addr.s_net  = ddp->deh_dnet;
1490	tosat.sat_addr.s_node = ddp->deh_dnode;
1491	tosat.sat_port	      = ddp->deh_dport;
1492
1493	sock = atalk_search_socket(&tosat, atif);
1494	if (!sock) /* But not one of our sockets */
1495		goto drop;
1496
1497	/* Queue packet (standard) */
1498	if (sock_queue_rcv_skb(sock, skb) < 0)
1499		goto drop;
1500
1501	return NET_RX_SUCCESS;
1502
1503drop:
1504	kfree_skb(skb);
1505out:
1506	return NET_RX_DROP;
1507
1508}
1509
1510/*
1511 * Receive a LocalTalk frame. We make some demands on the caller here.
1512 * Caller must provide enough headroom on the packet to pull the short
1513 * header and append a long one.
1514 */
1515static int ltalk_rcv(struct sk_buff *skb, struct net_device *dev,
1516		     struct packet_type *pt, struct net_device *orig_dev)
1517{
1518	if (!net_eq(dev_net(dev), &init_net))
1519		goto freeit;
1520
1521	/* Expand any short form frames */
1522	if (skb_mac_header(skb)[2] == 1) {
1523		struct ddpehdr *ddp;
1524		/* Find our address */
1525		struct atalk_addr *ap = atalk_find_dev_addr(dev);
1526
1527		if (!ap || skb->len < sizeof(__be16) || skb->len > 1023)
1528			goto freeit;
1529
1530		/* Don't mangle buffer if shared */
1531		if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
1532			return 0;
1533
1534		/*
1535		 * The push leaves us with a ddephdr not an shdr, and
1536		 * handily the port bytes in the right place preset.
1537		 */
1538		ddp = skb_push(skb, sizeof(*ddp) - 4);
1539
1540		/* Now fill in the long header */
1541
1542		/*
1543		 * These two first. The mac overlays the new source/dest
1544		 * network information so we MUST copy these before
1545		 * we write the network numbers !
1546		 */
1547
1548		ddp->deh_dnode = skb_mac_header(skb)[0];     /* From physical header */
1549		ddp->deh_snode = skb_mac_header(skb)[1];     /* From physical header */
1550
1551		ddp->deh_dnet  = ap->s_net;	/* Network number */
1552		ddp->deh_snet  = ap->s_net;
1553		ddp->deh_sum   = 0;		/* No checksum */
1554		/*
1555		 * Not sure about this bit...
1556		 */
1557		/* Non routable, so force a drop if we slip up later */
1558		ddp->deh_len_hops = htons(skb->len + (DDP_MAXHOPS << 10));
1559	}
1560	skb_reset_transport_header(skb);
1561
1562	return atalk_rcv(skb, dev, pt, orig_dev);
1563freeit:
1564	kfree_skb(skb);
1565	return 0;
1566}
1567
1568static int atalk_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1569{
1570	struct sock *sk = sock->sk;
1571	struct atalk_sock *at = at_sk(sk);
1572	DECLARE_SOCKADDR(struct sockaddr_at *, usat, msg->msg_name);
1573	int flags = msg->msg_flags;
1574	int loopback = 0;
1575	struct sockaddr_at local_satalk, gsat;
1576	struct sk_buff *skb;
1577	struct net_device *dev;
1578	struct ddpehdr *ddp;
1579	int size, hard_header_len;
1580	struct atalk_route *rt, *rt_lo = NULL;
1581	int err;
1582
1583	if (flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT))
1584		return -EINVAL;
1585
1586	if (len > DDP_MAXSZ)
1587		return -EMSGSIZE;
1588
1589	lock_sock(sk);
1590	if (usat) {
1591		err = -EBUSY;
1592		if (sock_flag(sk, SOCK_ZAPPED))
1593			if (atalk_autobind(sk) < 0)
1594				goto out;
1595
1596		err = -EINVAL;
1597		if (msg->msg_namelen < sizeof(*usat) ||
1598		    usat->sat_family != AF_APPLETALK)
1599			goto out;
1600
1601		err = -EPERM;
1602		/* netatalk didn't implement this check */
1603		if (usat->sat_addr.s_node == ATADDR_BCAST &&
1604		    !sock_flag(sk, SOCK_BROADCAST)) {
1605			goto out;
1606		}
1607	} else {
1608		err = -ENOTCONN;
1609		if (sk->sk_state != TCP_ESTABLISHED)
1610			goto out;
1611		usat = &local_satalk;
1612		usat->sat_family      = AF_APPLETALK;
1613		usat->sat_port	      = at->dest_port;
1614		usat->sat_addr.s_node = at->dest_node;
1615		usat->sat_addr.s_net  = at->dest_net;
1616	}
1617
1618	/* Build a packet */
1619	SOCK_DEBUG(sk, "SK %p: Got address.\n", sk);
1620
1621	/* For headers */
1622	size = sizeof(struct ddpehdr) + len + ddp_dl->header_length;
1623
1624	if (usat->sat_addr.s_net || usat->sat_addr.s_node == ATADDR_ANYNODE) {
1625		rt = atrtr_find(&usat->sat_addr);
1626	} else {
1627		struct atalk_addr at_hint;
1628
1629		at_hint.s_node = 0;
1630		at_hint.s_net  = at->src_net;
1631
1632		rt = atrtr_find(&at_hint);
1633	}
1634	err = -ENETUNREACH;
1635	if (!rt)
1636		goto out;
1637
1638	dev = rt->dev;
1639
1640	SOCK_DEBUG(sk, "SK %p: Size needed %d, device %s\n",
1641			sk, size, dev->name);
1642
1643	hard_header_len = dev->hard_header_len;
1644	/* Leave room for loopback hardware header if necessary */
1645	if (usat->sat_addr.s_node == ATADDR_BCAST &&
1646	    (dev->flags & IFF_LOOPBACK || !(rt->flags & RTF_GATEWAY))) {
1647		struct atalk_addr at_lo;
1648
1649		at_lo.s_node = 0;
1650		at_lo.s_net  = 0;
1651
1652		rt_lo = atrtr_find(&at_lo);
1653
1654		if (rt_lo && rt_lo->dev->hard_header_len > hard_header_len)
1655			hard_header_len = rt_lo->dev->hard_header_len;
1656	}
1657
1658	size += hard_header_len;
1659	release_sock(sk);
1660	skb = sock_alloc_send_skb(sk, size, (flags & MSG_DONTWAIT), &err);
1661	lock_sock(sk);
1662	if (!skb)
1663		goto out;
1664
1665	skb_reserve(skb, ddp_dl->header_length);
1666	skb_reserve(skb, hard_header_len);
1667	skb->dev = dev;
1668
1669	SOCK_DEBUG(sk, "SK %p: Begin build.\n", sk);
1670
1671	ddp = skb_put(skb, sizeof(struct ddpehdr));
1672	ddp->deh_len_hops  = htons(len + sizeof(*ddp));
1673	ddp->deh_dnet  = usat->sat_addr.s_net;
1674	ddp->deh_snet  = at->src_net;
1675	ddp->deh_dnode = usat->sat_addr.s_node;
1676	ddp->deh_snode = at->src_node;
1677	ddp->deh_dport = usat->sat_port;
1678	ddp->deh_sport = at->src_port;
1679
1680	SOCK_DEBUG(sk, "SK %p: Copy user data (%zd bytes).\n", sk, len);
1681
1682	err = memcpy_from_msg(skb_put(skb, len), msg, len);
1683	if (err) {
1684		kfree_skb(skb);
1685		err = -EFAULT;
1686		goto out;
1687	}
1688
1689	if (sk->sk_no_check_tx)
1690		ddp->deh_sum = 0;
1691	else
1692		ddp->deh_sum = atalk_checksum(skb, len + sizeof(*ddp));
1693
1694	/*
1695	 * Loopback broadcast packets to non gateway targets (ie routes
1696	 * to group we are in)
1697	 */
1698	if (ddp->deh_dnode == ATADDR_BCAST &&
1699	    !(rt->flags & RTF_GATEWAY) && !(dev->flags & IFF_LOOPBACK)) {
1700		struct sk_buff *skb2 = skb_copy(skb, GFP_KERNEL);
1701
1702		if (skb2) {
1703			loopback = 1;
1704			SOCK_DEBUG(sk, "SK %p: send out(copy).\n", sk);
1705			/*
1706			 * If it fails it is queued/sent above in the aarp queue
1707			 */
1708			aarp_send_ddp(dev, skb2, &usat->sat_addr, NULL);
1709		}
1710	}
1711
1712	if (dev->flags & IFF_LOOPBACK || loopback) {
1713		SOCK_DEBUG(sk, "SK %p: Loop back.\n", sk);
1714		/* loop back */
1715		skb_orphan(skb);
1716		if (ddp->deh_dnode == ATADDR_BCAST) {
1717			if (!rt_lo) {
1718				kfree_skb(skb);
1719				err = -ENETUNREACH;
1720				goto out;
1721			}
1722			dev = rt_lo->dev;
1723			skb->dev = dev;
1724		}
1725		ddp_dl->request(ddp_dl, skb, dev->dev_addr);
1726	} else {
1727		SOCK_DEBUG(sk, "SK %p: send out.\n", sk);
1728		if (rt->flags & RTF_GATEWAY) {
1729		    gsat.sat_addr = rt->gateway;
1730		    usat = &gsat;
1731		}
1732
1733		/*
1734		 * If it fails it is queued/sent above in the aarp queue
1735		 */
1736		aarp_send_ddp(dev, skb, &usat->sat_addr, NULL);
1737	}
1738	SOCK_DEBUG(sk, "SK %p: Done write (%zd).\n", sk, len);
1739
1740out:
1741	release_sock(sk);
1742	return err ? : len;
1743}
1744
1745static int atalk_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1746			 int flags)
1747{
1748	struct sock *sk = sock->sk;
1749	struct ddpehdr *ddp;
1750	int copied = 0;
1751	int offset = 0;
1752	int err = 0;
1753	struct sk_buff *skb;
1754
1755	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
1756						flags & MSG_DONTWAIT, &err);
1757	lock_sock(sk);
1758
1759	if (!skb)
1760		goto out;
1761
1762	/* FIXME: use skb->cb to be able to use shared skbs */
1763	ddp = ddp_hdr(skb);
1764	copied = ntohs(ddp->deh_len_hops) & 1023;
1765
1766	if (sk->sk_type != SOCK_RAW) {
1767		offset = sizeof(*ddp);
1768		copied -= offset;
1769	}
1770
1771	if (copied > size) {
1772		copied = size;
1773		msg->msg_flags |= MSG_TRUNC;
1774	}
1775	err = skb_copy_datagram_msg(skb, offset, msg, copied);
1776
1777	if (!err && msg->msg_name) {
1778		DECLARE_SOCKADDR(struct sockaddr_at *, sat, msg->msg_name);
1779		sat->sat_family      = AF_APPLETALK;
1780		sat->sat_port        = ddp->deh_sport;
1781		sat->sat_addr.s_node = ddp->deh_snode;
1782		sat->sat_addr.s_net  = ddp->deh_snet;
1783		msg->msg_namelen     = sizeof(*sat);
1784	}
1785
1786	skb_free_datagram(sk, skb);	/* Free the datagram. */
1787
1788out:
1789	release_sock(sk);
1790	return err ? : copied;
1791}
1792
1793
1794/*
1795 * AppleTalk ioctl calls.
1796 */
1797static int atalk_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1798{
1799	int rc = -ENOIOCTLCMD;
1800	struct sock *sk = sock->sk;
1801	void __user *argp = (void __user *)arg;
1802
1803	switch (cmd) {
1804	/* Protocol layer */
1805	case TIOCOUTQ: {
1806		long amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
1807
1808		if (amount < 0)
1809			amount = 0;
1810		rc = put_user(amount, (int __user *)argp);
1811		break;
1812	}
1813	case TIOCINQ: {
1814		struct sk_buff *skb;
1815		long amount = 0;
1816
1817		spin_lock_irq(&sk->sk_receive_queue.lock);
1818		skb = skb_peek(&sk->sk_receive_queue);
1819		if (skb)
1820			amount = skb->len - sizeof(struct ddpehdr);
1821		spin_unlock_irq(&sk->sk_receive_queue.lock);
1822		rc = put_user(amount, (int __user *)argp);
1823		break;
1824	}
1825	/* Routing */
1826	case SIOCADDRT:
1827	case SIOCDELRT:
1828		rc = -EPERM;
1829		if (capable(CAP_NET_ADMIN))
1830			rc = atrtr_ioctl(cmd, argp);
1831		break;
1832	/* Interface */
1833	case SIOCGIFADDR:
1834	case SIOCSIFADDR:
1835	case SIOCGIFBRDADDR:
1836	case SIOCATALKDIFADDR:
1837	case SIOCDIFADDR:
1838	case SIOCSARP:		/* proxy AARP */
1839	case SIOCDARP:		/* proxy AARP */
1840		rtnl_lock();
1841		rc = atif_ioctl(cmd, argp);
1842		rtnl_unlock();
1843		break;
1844	}
1845
1846	return rc;
1847}
1848
1849
1850#ifdef CONFIG_COMPAT
1851static int atalk_compat_routing_ioctl(struct sock *sk, unsigned int cmd,
1852		struct compat_rtentry __user *ur)
1853{
1854	compat_uptr_t rtdev;
1855	struct rtentry rt;
1856
1857	if (copy_from_user(&rt.rt_dst, &ur->rt_dst,
1858			3 * sizeof(struct sockaddr)) ||
1859	    get_user(rt.rt_flags, &ur->rt_flags) ||
1860	    get_user(rt.rt_metric, &ur->rt_metric) ||
1861	    get_user(rt.rt_mtu, &ur->rt_mtu) ||
1862	    get_user(rt.rt_window, &ur->rt_window) ||
1863	    get_user(rt.rt_irtt, &ur->rt_irtt) ||
1864	    get_user(rtdev, &ur->rt_dev))
1865		return -EFAULT;
1866
1867	switch (cmd) {
1868	case SIOCDELRT:
1869		if (rt.rt_dst.sa_family != AF_APPLETALK)
1870			return -EINVAL;
1871		return atrtr_delete(&((struct sockaddr_at *)
1872				      &rt.rt_dst)->sat_addr);
1873
1874	case SIOCADDRT:
1875		rt.rt_dev = compat_ptr(rtdev);
1876		return atrtr_ioctl_addrt(&rt);
1877	default:
1878		return -EINVAL;
1879	}
1880}
1881static int atalk_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1882{
1883	void __user *argp = compat_ptr(arg);
1884	struct sock *sk = sock->sk;
1885
1886	switch (cmd) {
1887	case SIOCADDRT:
1888	case SIOCDELRT:
1889		return atalk_compat_routing_ioctl(sk, cmd, argp);
1890	/*
1891	 * SIOCATALKDIFADDR is a SIOCPROTOPRIVATE ioctl number, so we
1892	 * cannot handle it in common code. The data we access if ifreq
1893	 * here is compatible, so we can simply call the native
1894	 * handler.
1895	 */
1896	case SIOCATALKDIFADDR:
1897		return atalk_ioctl(sock, cmd, (unsigned long)argp);
1898	default:
1899		return -ENOIOCTLCMD;
1900	}
1901}
1902#endif /* CONFIG_COMPAT */
1903
1904
1905static const struct net_proto_family atalk_family_ops = {
1906	.family		= PF_APPLETALK,
1907	.create		= atalk_create,
1908	.owner		= THIS_MODULE,
1909};
1910
1911static const struct proto_ops atalk_dgram_ops = {
1912	.family		= PF_APPLETALK,
1913	.owner		= THIS_MODULE,
1914	.release	= atalk_release,
1915	.bind		= atalk_bind,
1916	.connect	= atalk_connect,
1917	.socketpair	= sock_no_socketpair,
1918	.accept		= sock_no_accept,
1919	.getname	= atalk_getname,
1920	.poll		= datagram_poll,
1921	.ioctl		= atalk_ioctl,
1922	.gettstamp	= sock_gettstamp,
1923#ifdef CONFIG_COMPAT
1924	.compat_ioctl	= atalk_compat_ioctl,
1925#endif
1926	.listen		= sock_no_listen,
1927	.shutdown	= sock_no_shutdown,
1928	.sendmsg	= atalk_sendmsg,
1929	.recvmsg	= atalk_recvmsg,
1930	.mmap		= sock_no_mmap,
1931	.sendpage	= sock_no_sendpage,
1932};
1933
1934static struct notifier_block ddp_notifier = {
1935	.notifier_call	= ddp_device_event,
1936};
1937
1938static struct packet_type ltalk_packet_type __read_mostly = {
1939	.type		= cpu_to_be16(ETH_P_LOCALTALK),
1940	.func		= ltalk_rcv,
1941};
1942
1943static struct packet_type ppptalk_packet_type __read_mostly = {
1944	.type		= cpu_to_be16(ETH_P_PPPTALK),
1945	.func		= atalk_rcv,
1946};
1947
1948static unsigned char ddp_snap_id[] = { 0x08, 0x00, 0x07, 0x80, 0x9B };
1949
1950/* Export symbols for use by drivers when AppleTalk is a module */
1951EXPORT_SYMBOL(atrtr_get_dev);
1952EXPORT_SYMBOL(atalk_find_dev_addr);
1953
1954/* Called by proto.c on kernel start up */
1955static int __init atalk_init(void)
1956{
1957	int rc;
1958
1959	rc = proto_register(&ddp_proto, 0);
1960	if (rc)
1961		goto out;
1962
1963	rc = sock_register(&atalk_family_ops);
1964	if (rc)
1965		goto out_proto;
1966
1967	ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv);
1968	if (!ddp_dl) {
1969		pr_crit("Unable to register DDP with SNAP.\n");
1970		rc = -ENOMEM;
1971		goto out_sock;
1972	}
1973
1974	dev_add_pack(&ltalk_packet_type);
1975	dev_add_pack(&ppptalk_packet_type);
1976
1977	rc = register_netdevice_notifier(&ddp_notifier);
1978	if (rc)
1979		goto out_snap;
1980
1981	rc = aarp_proto_init();
1982	if (rc)
1983		goto out_dev;
1984
1985	rc = atalk_proc_init();
1986	if (rc)
1987		goto out_aarp;
1988
1989	rc = atalk_register_sysctl();
1990	if (rc)
1991		goto out_proc;
1992out:
1993	return rc;
1994out_proc:
1995	atalk_proc_exit();
1996out_aarp:
1997	aarp_cleanup_module();
1998out_dev:
1999	unregister_netdevice_notifier(&ddp_notifier);
2000out_snap:
2001	dev_remove_pack(&ppptalk_packet_type);
2002	dev_remove_pack(&ltalk_packet_type);
2003	unregister_snap_client(ddp_dl);
2004out_sock:
2005	sock_unregister(PF_APPLETALK);
2006out_proto:
2007	proto_unregister(&ddp_proto);
2008	goto out;
2009}
2010module_init(atalk_init);
2011
2012/*
2013 * No explicit module reference count manipulation is needed in the
2014 * protocol. Socket layer sets module reference count for us
2015 * and interfaces reference counting is done
2016 * by the network device layer.
2017 *
2018 * Ergo, before the AppleTalk module can be removed, all AppleTalk
2019 * sockets be closed from user space.
2020 */
2021static void __exit atalk_exit(void)
2022{
2023#ifdef CONFIG_SYSCTL
2024	atalk_unregister_sysctl();
2025#endif /* CONFIG_SYSCTL */
2026	atalk_proc_exit();
2027	aarp_cleanup_module();	/* General aarp clean-up. */
2028	unregister_netdevice_notifier(&ddp_notifier);
2029	dev_remove_pack(&ltalk_packet_type);
2030	dev_remove_pack(&ppptalk_packet_type);
2031	unregister_snap_client(ddp_dl);
2032	sock_unregister(PF_APPLETALK);
2033	proto_unregister(&ddp_proto);
2034}
2035module_exit(atalk_exit);
2036
2037MODULE_LICENSE("GPL");
2038MODULE_AUTHOR("Alan Cox <alan@lxorguk.ukuu.org.uk>");
2039MODULE_DESCRIPTION("AppleTalk 0.20\n");
2040MODULE_ALIAS_NETPROTO(PF_APPLETALK);
2041