Phonet: Implement Pipe Controller to support Nokia Slim Modems
[linux-2.6.git] / net / phonet / af_phonet.c
1 /*
2  * File: af_phonet.c
3  *
4  * Phonet protocols family
5  *
6  * Copyright (C) 2008 Nokia Corporation.
7  *
8  * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
9  * Original author: Sakari Ailus <sakari.ailus@nokia.com>
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 struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
39
40 static struct phonet_protocol *phonet_proto_get(int protocol)
41 {
42         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(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         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);
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->resource = 0;
114         sk->sk_prot->init(sk);
115         err = 0;
116
117 out:
118         phonet_proto_put(pnp);
119         return err;
120 }
121
122 static const struct net_proto_family phonet_proto_family = {
123         .family = PF_PHONET,
124         .create = pn_socket_create,
125         .owner = THIS_MODULE,
126 };
127
128 /* Phonet device header operations */
129 static int pn_header_create(struct sk_buff *skb, struct net_device *dev,
130                                 unsigned short type, const void *daddr,
131                                 const void *saddr, unsigned len)
132 {
133         u8 *media = skb_push(skb, 1);
134
135         if (type != ETH_P_PHONET)
136                 return -1;
137
138         if (!saddr)
139                 saddr = dev->dev_addr;
140         *media = *(const u8 *)saddr;
141         return 1;
142 }
143
144 static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr)
145 {
146         const u8 *media = skb_mac_header(skb);
147         *haddr = *media;
148         return 1;
149 }
150
151 struct header_ops phonet_header_ops = {
152         .create = pn_header_create,
153         .parse = pn_header_parse,
154 };
155 EXPORT_SYMBOL(phonet_header_ops);
156
157 /*
158  * Prepends an ISI header and sends a datagram.
159  */
160 static int pn_send(struct sk_buff *skb, struct net_device *dev,
161                         u16 dst, u16 src, u8 res, u8 irq)
162 {
163         struct phonethdr *ph;
164         int err;
165
166         if (skb->len + 2 > 0xffff /* Phonet length field limit */ ||
167             skb->len + sizeof(struct phonethdr) > dev->mtu) {
168                 err = -EMSGSIZE;
169                 goto drop;
170         }
171
172         /* Broadcast sending is not implemented */
173         if (pn_addr(dst) == PNADDR_BROADCAST) {
174                 err = -EOPNOTSUPP;
175                 goto drop;
176         }
177
178         skb_reset_transport_header(skb);
179         WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */
180         skb_push(skb, sizeof(struct phonethdr));
181         skb_reset_network_header(skb);
182         ph = pn_hdr(skb);
183         ph->pn_rdev = pn_dev(dst);
184         ph->pn_sdev = pn_dev(src);
185         ph->pn_res = res;
186         ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph));
187         ph->pn_robj = pn_obj(dst);
188         ph->pn_sobj = pn_obj(src);
189
190         skb->protocol = htons(ETH_P_PHONET);
191         skb->priority = 0;
192         skb->dev = dev;
193
194         if (skb->pkt_type == PACKET_LOOPBACK) {
195                 skb_reset_mac_header(skb);
196                 skb_orphan(skb);
197                 if (irq)
198                         netif_rx(skb);
199                 else
200                         netif_rx_ni(skb);
201                 err = 0;
202         } else {
203                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
204                                         NULL, NULL, skb->len);
205                 if (err < 0) {
206                         err = -EHOSTUNREACH;
207                         goto drop;
208                 }
209                 err = dev_queue_xmit(skb);
210         }
211
212         return err;
213 drop:
214         kfree_skb(skb);
215         return err;
216 }
217
218 static int pn_raw_send(const void *data, int len, struct net_device *dev,
219                         u16 dst, u16 src, u8 res)
220 {
221         struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC);
222         if (skb == NULL)
223                 return -ENOMEM;
224
225         if (phonet_address_lookup(dev_net(dev), pn_addr(dst)) == 0)
226                 skb->pkt_type = PACKET_LOOPBACK;
227
228         skb_reserve(skb, MAX_PHONET_HEADER);
229         __skb_put(skb, len);
230         skb_copy_to_linear_data(skb, data, len);
231         return pn_send(skb, dev, dst, src, res, 1);
232 }
233
234 /*
235  * Create a Phonet header for the skb and send it out. Returns
236  * non-zero error code if failed. The skb is freed then.
237  */
238 int pn_skb_send(struct sock *sk, struct sk_buff *skb,
239                 const struct sockaddr_pn *target)
240 {
241         struct net *net = sock_net(sk);
242         struct net_device *dev;
243         struct pn_sock *pn = pn_sk(sk);
244         int err;
245         u16 src;
246         u8 daddr = pn_sockaddr_get_addr(target), saddr = PN_NO_ADDR;
247
248         err = -EHOSTUNREACH;
249         if (sk->sk_bound_dev_if)
250                 dev = dev_get_by_index(net, sk->sk_bound_dev_if);
251         else if (phonet_address_lookup(net, daddr) == 0) {
252                 dev = phonet_device_get(net);
253                 skb->pkt_type = PACKET_LOOPBACK;
254         } else if (pn_sockaddr_get_object(target) == 0) {
255                 /* Resource routing (small race until phonet_rcv()) */
256                 struct sock *sk = pn_find_sock_by_res(net,
257                                                         target->spn_resource);
258                 if (sk) {
259                         sock_put(sk);
260                         dev = phonet_device_get(net);
261                         skb->pkt_type = PACKET_LOOPBACK;
262                 } else
263                         dev = phonet_route_output(net, daddr);
264         } else
265                 dev = phonet_route_output(net, daddr);
266
267         if (!dev || !(dev->flags & IFF_UP))
268                 goto drop;
269
270         saddr = phonet_address_get(dev, daddr);
271         if (saddr == PN_NO_ADDR)
272                 goto drop;
273
274         src = pn->sobject;
275         if (!pn_addr(src))
276                 src = pn_object(saddr, pn_obj(src));
277
278         err = pn_send(skb, dev, pn_sockaddr_get_object(target),
279                         src, pn_sockaddr_get_resource(target), 0);
280         dev_put(dev);
281         return err;
282
283 drop:
284         kfree_skb(skb);
285         if (dev)
286                 dev_put(dev);
287         return err;
288 }
289 EXPORT_SYMBOL(pn_skb_send);
290
291 /* Do not send an error message in response to an error message */
292 static inline int can_respond(struct sk_buff *skb)
293 {
294         const struct phonethdr *ph;
295         const struct phonetmsg *pm;
296         u8 submsg_id;
297
298         if (!pskb_may_pull(skb, 3))
299                 return 0;
300
301         ph = pn_hdr(skb);
302         if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
303                 return 0;
304         if (ph->pn_res == PN_COMMGR) /* indications */
305                 return 0;
306
307         ph = pn_hdr(skb); /* re-acquires the pointer */
308         pm = pn_msg(skb);
309         if (pm->pn_msg_id != PN_COMMON_MESSAGE)
310                 return 1;
311         submsg_id = (ph->pn_res == PN_PREFIX)
312                 ? pm->pn_e_submsg_id : pm->pn_submsg_id;
313         if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
314                 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
315                 return 1;
316         return 0;
317 }
318
319 static int send_obj_unreachable(struct sk_buff *rskb)
320 {
321         const struct phonethdr *oph = pn_hdr(rskb);
322         const struct phonetmsg *opm = pn_msg(rskb);
323         struct phonetmsg resp;
324
325         memset(&resp, 0, sizeof(resp));
326         resp.pn_trans_id = opm->pn_trans_id;
327         resp.pn_msg_id = PN_COMMON_MESSAGE;
328         if (oph->pn_res == PN_PREFIX) {
329                 resp.pn_e_res_id = opm->pn_e_res_id;
330                 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
331                 resp.pn_e_orig_msg_id = opm->pn_msg_id;
332                 resp.pn_e_status = 0;
333         } else {
334                 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
335                 resp.pn_orig_msg_id = opm->pn_msg_id;
336                 resp.pn_status = 0;
337         }
338         return pn_raw_send(&resp, sizeof(resp), rskb->dev,
339                                 pn_object(oph->pn_sdev, oph->pn_sobj),
340                                 pn_object(oph->pn_rdev, oph->pn_robj),
341                                 oph->pn_res);
342 }
343
344 static int send_reset_indications(struct sk_buff *rskb)
345 {
346         struct phonethdr *oph = pn_hdr(rskb);
347         static const u8 data[4] = {
348                 0x00 /* trans ID */, 0x10 /* subscribe msg */,
349                 0x00 /* subscription count */, 0x00 /* dummy */
350         };
351
352         return pn_raw_send(data, sizeof(data), rskb->dev,
353                                 pn_object(oph->pn_sdev, 0x00),
354                                 pn_object(oph->pn_rdev, oph->pn_robj),
355                                 PN_COMMGR);
356 }
357
358
359 /* packet type functions */
360
361 /*
362  * Stuff received packets to associated sockets.
363  * On error, returns non-zero and releases the skb.
364  */
365 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
366                         struct packet_type *pkttype,
367                         struct net_device *orig_dev)
368 {
369         struct net *net = dev_net(dev);
370         struct phonethdr *ph;
371         struct sockaddr_pn sa;
372         u16 len;
373
374         /* check we have at least a full Phonet header */
375         if (!pskb_pull(skb, sizeof(struct phonethdr)))
376                 goto out;
377
378         /* check that the advertised length is correct */
379         ph = pn_hdr(skb);
380         len = get_unaligned_be16(&ph->pn_length);
381         if (len < 2)
382                 goto out;
383         len -= 2;
384         if ((len > skb->len) || pskb_trim(skb, len))
385                 goto out;
386         skb_reset_transport_header(skb);
387
388         pn_skb_get_dst_sockaddr(skb, &sa);
389
390         /* check if this is broadcasted */
391         if (pn_sockaddr_get_addr(&sa) == PNADDR_BROADCAST) {
392                 pn_deliver_sock_broadcast(net, skb);
393                 goto out;
394         }
395
396         /* resource routing */
397         if (pn_sockaddr_get_object(&sa) == 0) {
398                 struct sock *sk = pn_find_sock_by_res(net, sa.spn_resource);
399                 if (sk)
400                         return sk_receive_skb(sk, skb, 0);
401         }
402
403         /* check if we are the destination */
404         if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) {
405                 /* Phonet packet input */
406                 struct sock *sk = pn_find_sock_by_sa(net, &sa);
407
408                 if (sk)
409                         return sk_receive_skb(sk, skb, 0);
410
411                 if (can_respond(skb)) {
412                         send_obj_unreachable(skb);
413                         send_reset_indications(skb);
414                 }
415         } else if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
416                 goto out; /* Race between address deletion and loopback */
417         else {
418                 /* Phonet packet routing */
419                 struct net_device *out_dev;
420
421                 out_dev = phonet_route_output(net, pn_sockaddr_get_addr(&sa));
422                 if (!out_dev) {
423                         LIMIT_NETDEBUG(KERN_WARNING"No Phonet route to %02X\n",
424                                         pn_sockaddr_get_addr(&sa));
425                         goto out;
426                 }
427
428                 __skb_push(skb, sizeof(struct phonethdr));
429                 skb->dev = out_dev;
430                 if (out_dev == dev) {
431                         LIMIT_NETDEBUG(KERN_ERR"Phonet loop to %02X on %s\n",
432                                         pn_sockaddr_get_addr(&sa), dev->name);
433                         goto out_dev;
434                 }
435                 /* Some drivers (e.g. TUN) do not allocate HW header space */
436                 if (skb_cow_head(skb, out_dev->hard_header_len))
437                         goto out_dev;
438
439                 if (dev_hard_header(skb, out_dev, ETH_P_PHONET, NULL, NULL,
440                                         skb->len) < 0)
441                         goto out_dev;
442                 dev_queue_xmit(skb);
443                 dev_put(out_dev);
444                 return NET_RX_SUCCESS;
445 out_dev:
446                 dev_put(out_dev);
447         }
448
449 out:
450         kfree_skb(skb);
451         return NET_RX_DROP;
452 }
453
454 static struct packet_type phonet_packet_type __read_mostly = {
455         .type = cpu_to_be16(ETH_P_PHONET),
456         .func = phonet_rcv,
457 };
458
459 static DEFINE_MUTEX(proto_tab_lock);
460
461 int __init_or_module phonet_proto_register(int protocol,
462                                                 struct phonet_protocol *pp)
463 {
464         int err = 0;
465
466         if (protocol >= PHONET_NPROTO)
467                 return -EINVAL;
468
469         err = proto_register(pp->prot, 1);
470         if (err)
471                 return err;
472
473         mutex_lock(&proto_tab_lock);
474         if (proto_tab[protocol])
475                 err = -EBUSY;
476         else
477                 rcu_assign_pointer(proto_tab[protocol], pp);
478         mutex_unlock(&proto_tab_lock);
479
480         return err;
481 }
482 EXPORT_SYMBOL(phonet_proto_register);
483
484 void phonet_proto_unregister(int protocol, struct phonet_protocol *pp)
485 {
486         mutex_lock(&proto_tab_lock);
487         BUG_ON(proto_tab[protocol] != pp);
488         rcu_assign_pointer(proto_tab[protocol], NULL);
489         mutex_unlock(&proto_tab_lock);
490         synchronize_rcu();
491         proto_unregister(pp->prot);
492 }
493 EXPORT_SYMBOL(phonet_proto_unregister);
494
495 /* Module registration */
496 static int __init phonet_init(void)
497 {
498         int err;
499
500         err = phonet_device_init();
501         if (err)
502                 return err;
503
504         pn_sock_init();
505         err = sock_register(&phonet_proto_family);
506         if (err) {
507                 printk(KERN_ALERT
508                         "phonet protocol family initialization failed\n");
509                 goto err_sock;
510         }
511
512         dev_add_pack(&phonet_packet_type);
513         phonet_sysctl_init();
514
515         err = isi_register();
516         if (err)
517                 goto err;
518         return 0;
519
520 err:
521         phonet_sysctl_exit();
522         sock_unregister(PF_PHONET);
523         dev_remove_pack(&phonet_packet_type);
524 err_sock:
525         phonet_device_exit();
526         return err;
527 }
528
529 static void __exit phonet_exit(void)
530 {
531         isi_unregister();
532         phonet_sysctl_exit();
533         sock_unregister(PF_PHONET);
534         dev_remove_pack(&phonet_packet_type);
535         phonet_device_exit();
536 }
537
538 module_init(phonet_init);
539 module_exit(phonet_exit);
540 MODULE_DESCRIPTION("Phonet protocol stack for Linux");
541 MODULE_LICENSE("GPL");
542 MODULE_ALIAS_NETPROTO(PF_PHONET);