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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / net / phonet / af_phonet.c
blob3b0ef691f5b1ba532a19e74c910356ada9ac3b6c
1 /*
2 * File: af_phonet.c
3 *
4 * Phonet protocols family
5 *
6 * Copyright (C) 2008 Nokia Corporation.
7 *
8 * Authors: Sakari Ailus <sakari.ailus@nokia.com>
9 * Rémi Denis-Courmont
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * version 2 as published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
23 * 02110-1301 USA
24 */
25
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <linux/slab.h>
29 #include <asm/unaligned.h>
30 #include <net/sock.h>
31
32 #include <linux/if_phonet.h>
33 #include <linux/phonet.h>
34 #include <net/phonet/phonet.h>
35 #include <net/phonet/pn_dev.h>
36
37 /* Transport protocol registration */
38 static const struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
39
40 static const struct phonet_protocol *phonet_proto_get(unsigned int protocol)
41 {
42 const struct phonet_protocol *pp;
43
44 if (protocol >= PHONET_NPROTO)
45 return NULL;
46
47 rcu_read_lock();
48 pp = rcu_dereference(proto_tab[protocol]);
49 if (pp && !try_module_get(pp->prot->owner))
50 pp = NULL;
51 rcu_read_unlock();
52
53 return pp;
54 }
55
56 static inline void phonet_proto_put(const struct phonet_protocol *pp)
57 {
58 module_put(pp->prot->owner);
59 }
60
61 /* protocol family functions */
62
63 static int pn_socket_create(struct net *net, struct socket *sock, int protocol,
64 int kern)
65 {
66 struct sock *sk;
67 struct pn_sock *pn;
68 const struct phonet_protocol *pnp;
69 int err;
70
71 if (!capable(CAP_SYS_ADMIN))
72 return -EPERM;
73
74 if (protocol == 0) {
75 /* Default protocol selection */
76 switch (sock->type) {
77 case SOCK_DGRAM:
78 protocol = PN_PROTO_PHONET;
79 break;
80 case SOCK_SEQPACKET:
81 protocol = PN_PROTO_PIPE;
82 break;
83 default:
84 return -EPROTONOSUPPORT;
85 }
86 }
87
88 pnp = phonet_proto_get(protocol);
89 if (pnp == NULL &&
90 request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0)
91 pnp = phonet_proto_get(protocol);
92
93 if (pnp == NULL)
94 return -EPROTONOSUPPORT;
95 if (sock->type != pnp->sock_type) {
96 err = -EPROTONOSUPPORT;
97 goto out;
98 }
99
100 sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot, kern);
101 if (sk == NULL) {
102 err = -ENOMEM;
103 goto out;
104 }
105
106 sock_init_data(sock, sk);
107 sock->state = SS_UNCONNECTED;
108 sock->ops = pnp->ops;
109 sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
110 sk->sk_protocol = protocol;
111 pn = pn_sk(sk);
112 pn->sobject = 0;
113 pn->dobject = 0;
114 pn->resource = 0;
115 sk->sk_prot->init(sk);
116 err = 0;
117
118 out:
119 phonet_proto_put(pnp);
120 return err;
121 }
122
123 static const struct net_proto_family phonet_proto_family = {
124 .family = PF_PHONET,
125 .create = pn_socket_create,
126 .owner = THIS_MODULE,
127 };
128
129 /* Phonet device header operations */
130 static int pn_header_create(struct sk_buff *skb, struct net_device *dev,
131 unsigned short type, const void *daddr,
132 const void *saddr, unsigned int len)
133 {
134 u8 *media = skb_push(skb, 1);
135
136 if (type != ETH_P_PHONET)
137 return -1;
138
139 if (!saddr)
140 saddr = dev->dev_addr;
141 *media = *(const u8 *)saddr;
142 return 1;
143 }
144
145 static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr)
146 {
147 const u8 *media = skb_mac_header(skb);
148 *haddr = *media;
149 return 1;
150 }
151
152 const struct header_ops phonet_header_ops = {
153 .create = pn_header_create,
154 .parse = pn_header_parse,
155 };
156 EXPORT_SYMBOL(phonet_header_ops);
157
158 /*
159 * Prepends an ISI header and sends a datagram.
160 */
161 static int pn_send(struct sk_buff *skb, struct net_device *dev,
162 u16 dst, u16 src, u8 res, u8 irq)
163 {
164 struct phonethdr *ph;
165 int err;
166
167 if (skb->len + 2 > 0xffff /* Phonet length field limit */ ||
168 skb->len + sizeof(struct phonethdr) > dev->mtu) {
169 err = -EMSGSIZE;
170 goto drop;
171 }
172
173 /* Broadcast sending is not implemented */
174 if (pn_addr(dst) == PNADDR_BROADCAST) {
175 err = -EOPNOTSUPP;
176 goto drop;
177 }
178
179 skb_reset_transport_header(skb);
180 WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */
181 skb_push(skb, sizeof(struct phonethdr));
182 skb_reset_network_header(skb);
183 ph = pn_hdr(skb);
184 ph->pn_rdev = pn_dev(dst);
185 ph->pn_sdev = pn_dev(src);
186 ph->pn_res = res;
187 ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph));
188 ph->pn_robj = pn_obj(dst);
189 ph->pn_sobj = pn_obj(src);
190
191 skb->protocol = htons(ETH_P_PHONET);
192 skb->priority = 0;
193 skb->dev = dev;
194
195 if (skb->pkt_type == PACKET_LOOPBACK) {
196 skb_reset_mac_header(skb);
197 skb_orphan(skb);
198 err = (irq ? netif_rx(skb) : netif_rx_ni(skb)) ? -ENOBUFS : 0;
199 } else {
200 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
201 NULL, NULL, skb->len);
202 if (err < 0) {
203 err = -EHOSTUNREACH;
204 goto drop;
205 }
206 err = dev_queue_xmit(skb);
207 if (unlikely(err > 0))
208 err = net_xmit_errno(err);
209 }
210
211 return err;
212 drop:
213 kfree_skb(skb);
214 return err;
215 }
216
217 static int pn_raw_send(const void *data, int len, struct net_device *dev,
218 u16 dst, u16 src, u8 res)
219 {
220 struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC);
221 if (skb == NULL)
222 return -ENOMEM;
223
224 if (phonet_address_lookup(dev_net(dev), pn_addr(dst)) == 0)
225 skb->pkt_type = PACKET_LOOPBACK;
226
227 skb_reserve(skb, MAX_PHONET_HEADER);
228 __skb_put(skb, len);
229 skb_copy_to_linear_data(skb, data, len);
230 return pn_send(skb, dev, dst, src, res, 1);
231 }
232
233 /*
234 * Create a Phonet header for the skb and send it out. Returns
235 * non-zero error code if failed. The skb is freed then.
236 */
237 int pn_skb_send(struct sock *sk, struct sk_buff *skb,
238 const struct sockaddr_pn *target)
239 {
240 struct net *net = sock_net(sk);
241 struct net_device *dev;
242 struct pn_sock *pn = pn_sk(sk);
243 int err;
244 u16 src, dst;
245 u8 daddr, saddr, res;
246
247 src = pn->sobject;
248 if (target != NULL) {
249 dst = pn_sockaddr_get_object(target);
250 res = pn_sockaddr_get_resource(target);
251 } else {
252 dst = pn->dobject;
253 res = pn->resource;
254 }
255 daddr = pn_addr(dst);
256
257 err = -EHOSTUNREACH;
258 if (sk->sk_bound_dev_if)
259 dev = dev_get_by_index(net, sk->sk_bound_dev_if);
260 else if (phonet_address_lookup(net, daddr) == 0) {
261 dev = phonet_device_get(net);
262 skb->pkt_type = PACKET_LOOPBACK;
263 } else if (dst == 0) {
264 /* Resource routing (small race until phonet_rcv()) */
265 struct sock *sk = pn_find_sock_by_res(net, res);
266 if (sk) {
267 sock_put(sk);
268 dev = phonet_device_get(net);
269 skb->pkt_type = PACKET_LOOPBACK;
270 } else
271 dev = phonet_route_output(net, daddr);
272 } else
273 dev = phonet_route_output(net, daddr);
274
275 if (!dev || !(dev->flags & IFF_UP))
276 goto drop;
277
278 saddr = phonet_address_get(dev, daddr);
279 if (saddr == PN_NO_ADDR)
280 goto drop;
281
282 if (!pn_addr(src))
283 src = pn_object(saddr, pn_obj(src));
284
285 err = pn_send(skb, dev, dst, src, res, 0);
286 dev_put(dev);
287 return err;
288
289 drop:
290 kfree_skb(skb);
291 if (dev)
292 dev_put(dev);
293 return err;
294 }
295 EXPORT_SYMBOL(pn_skb_send);
296
297 /* Do not send an error message in response to an error message */
298 static inline int can_respond(struct sk_buff *skb)
299 {
300 const struct phonethdr *ph;
301 const struct phonetmsg *pm;
302 u8 submsg_id;
303
304 if (!pskb_may_pull(skb, 3))
305 return 0;
306
307 ph = pn_hdr(skb);
308 if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
309 return 0;
310 if (ph->pn_res == PN_COMMGR) /* indications */
311 return 0;
312
313 ph = pn_hdr(skb); /* re-acquires the pointer */
314 pm = pn_msg(skb);
315 if (pm->pn_msg_id != PN_COMMON_MESSAGE)
316 return 1;
317 submsg_id = (ph->pn_res == PN_PREFIX)
318 ? pm->pn_e_submsg_id : pm->pn_submsg_id;
319 if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
320 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
321 return 1;
322 return 0;
323 }
324
325 static int send_obj_unreachable(struct sk_buff *rskb)
326 {
327 const struct phonethdr *oph = pn_hdr(rskb);
328 const struct phonetmsg *opm = pn_msg(rskb);
329 struct phonetmsg resp;
330
331 memset(&resp, 0, sizeof(resp));
332 resp.pn_trans_id = opm->pn_trans_id;
333 resp.pn_msg_id = PN_COMMON_MESSAGE;
334 if (oph->pn_res == PN_PREFIX) {
335 resp.pn_e_res_id = opm->pn_e_res_id;
336 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
337 resp.pn_e_orig_msg_id = opm->pn_msg_id;
338 resp.pn_e_status = 0;
339 } else {
340 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
341 resp.pn_orig_msg_id = opm->pn_msg_id;
342 resp.pn_status = 0;
343 }
344 return pn_raw_send(&resp, sizeof(resp), rskb->dev,
345 pn_object(oph->pn_sdev, oph->pn_sobj),
346 pn_object(oph->pn_rdev, oph->pn_robj),
347 oph->pn_res);
348 }
349
350 static int send_reset_indications(struct sk_buff *rskb)
351 {
352 struct phonethdr *oph = pn_hdr(rskb);
353 static const u8 data[4] = {
354 0x00 /* trans ID */, 0x10 /* subscribe msg */,
355 0x00 /* subscription count */, 0x00 /* dummy */
356 };
357
358 return pn_raw_send(data, sizeof(data), rskb->dev,
359 pn_object(oph->pn_sdev, 0x00),
360 pn_object(oph->pn_rdev, oph->pn_robj),
361 PN_COMMGR);
362 }
363
364
365 /* packet type functions */
366
367 /*
368 * Stuff received packets to associated sockets.
369 * On error, returns non-zero and releases the skb.
370 */
371 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
372 struct packet_type *pkttype,
373 struct net_device *orig_dev)
374 {
375 struct net *net = dev_net(dev);
376 struct phonethdr *ph;
377 struct sockaddr_pn sa;
378 u16 len;
379
380 skb = skb_share_check(skb, GFP_ATOMIC);
381 if (!skb)
382 return NET_RX_DROP;
383
384 /* check we have at least a full Phonet header */
385 if (!pskb_pull(skb, sizeof(struct phonethdr)))
386 goto out;
387
388 /* check that the advertised length is correct */
389 ph = pn_hdr(skb);
390 len = get_unaligned_be16(&ph->pn_length);
391 if (len < 2)
392 goto out;
393 len -= 2;
394 if ((len > skb->len) || pskb_trim(skb, len))
395 goto out;
396 skb_reset_transport_header(skb);
397
398 pn_skb_get_dst_sockaddr(skb, &sa);
399
400 /* check if this is broadcasted */
401 if (pn_sockaddr_get_addr(&sa) == PNADDR_BROADCAST) {
402 pn_deliver_sock_broadcast(net, skb);
403 goto out;
404 }
405
406 /* resource routing */
407 if (pn_sockaddr_get_object(&sa) == 0) {
408 struct sock *sk = pn_find_sock_by_res(net, sa.spn_resource);
409 if (sk)
410 return sk_receive_skb(sk, skb, 0);
411 }
412
413 /* check if we are the destination */
414 if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) {
415 /* Phonet packet input */
416 struct sock *sk = pn_find_sock_by_sa(net, &sa);
417
418 if (sk)
419 return sk_receive_skb(sk, skb, 0);
420
421 if (can_respond(skb)) {
422 send_obj_unreachable(skb);
423 send_reset_indications(skb);
424 }
425 } else if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
426 goto out; /* Race between address deletion and loopback */
427 else {
428 /* Phonet packet routing */
429 struct net_device *out_dev;
430
431 out_dev = phonet_route_output(net, pn_sockaddr_get_addr(&sa));
432 if (!out_dev) {
433 net_dbg_ratelimited("No Phonet route to %02X\n",
434 pn_sockaddr_get_addr(&sa));
435 goto out;
436 }
437
438 __skb_push(skb, sizeof(struct phonethdr));
439 skb->dev = out_dev;
440 if (out_dev == dev) {
441 net_dbg_ratelimited("Phonet loop to %02X on %s\n",
442 pn_sockaddr_get_addr(&sa),
443 dev->name);
444 goto out_dev;
445 }
446 /* Some drivers (e.g. TUN) do not allocate HW header space */
447 if (skb_cow_head(skb, out_dev->hard_header_len))
448 goto out_dev;
449
450 if (dev_hard_header(skb, out_dev, ETH_P_PHONET, NULL, NULL,
451 skb->len) < 0)
452 goto out_dev;
453 dev_queue_xmit(skb);
454 dev_put(out_dev);
455 return NET_RX_SUCCESS;
456 out_dev:
457 dev_put(out_dev);
458 }
459
460 out:
461 kfree_skb(skb);
462 return NET_RX_DROP;
463 }
464
465 static struct packet_type phonet_packet_type __read_mostly = {
466 .type = cpu_to_be16(ETH_P_PHONET),
467 .func = phonet_rcv,
468 };
469
470 static DEFINE_MUTEX(proto_tab_lock);
471
472 int __init_or_module phonet_proto_register(unsigned int protocol,
473 const struct phonet_protocol *pp)
474 {
475 int err = 0;
476
477 if (protocol >= PHONET_NPROTO)
478 return -EINVAL;
479
480 err = proto_register(pp->prot, 1);
481 if (err)
482 return err;
483
484 mutex_lock(&proto_tab_lock);
485 if (proto_tab[protocol])
486 err = -EBUSY;
487 else
488 rcu_assign_pointer(proto_tab[protocol], pp);
489 mutex_unlock(&proto_tab_lock);
490
491 return err;
492 }
493 EXPORT_SYMBOL(phonet_proto_register);
494
495 void phonet_proto_unregister(unsigned int protocol,
496 const struct phonet_protocol *pp)
497 {
498 mutex_lock(&proto_tab_lock);
499 BUG_ON(proto_tab[protocol] != pp);
500 RCU_INIT_POINTER(proto_tab[protocol], NULL);
501 mutex_unlock(&proto_tab_lock);
502 synchronize_rcu();
503 proto_unregister(pp->prot);
504 }
505 EXPORT_SYMBOL(phonet_proto_unregister);
506
507 /* Module registration */
508 static int __init phonet_init(void)
509 {
510 int err;
511
512 err = phonet_device_init();
513 if (err)
514 return err;
515
516 pn_sock_init();
517 err = sock_register(&phonet_proto_family);
518 if (err) {
519 printk(KERN_ALERT
520 "phonet protocol family initialization failed\n");
521 goto err_sock;
522 }
523
524 dev_add_pack(&phonet_packet_type);
525 phonet_sysctl_init();
526
527 err = isi_register();
528 if (err)
529 goto err;
530 return 0;
531
532 err:
533 phonet_sysctl_exit();
534 sock_unregister(PF_PHONET);
535 dev_remove_pack(&phonet_packet_type);
536 err_sock:
537 phonet_device_exit();
538 return err;
539 }
540
541 static void __exit phonet_exit(void)
542 {
543 isi_unregister();
544 phonet_sysctl_exit();
545 sock_unregister(PF_PHONET);
546 dev_remove_pack(&phonet_packet_type);
547 phonet_device_exit();
548 }
549
550 module_init(phonet_init);
551 module_exit(phonet_exit);
552 MODULE_DESCRIPTION("Phonet protocol stack for Linux");
553 MODULE_LICENSE("GPL");
554 MODULE_ALIAS_NETPROTO(PF_PHONET);
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