9d211f12582ba90882ae9f272a6896b716d83af4
[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 <asm/unaligned.h>
29 #include <net/sock.h>
30
31 #include <linux/if_phonet.h>
32 #include <linux/phonet.h>
33 #include <net/phonet/phonet.h>
34 #include <net/phonet/pn_dev.h>
35
36 /* Transport protocol registration */
37 static struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
38 static DEFINE_SPINLOCK(proto_tab_lock);
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         spin_lock(&proto_tab_lock);
48         pp = proto_tab[protocol];
49         if (pp && !try_module_get(pp->prot->owner))
50                 pp = NULL;
51         spin_unlock(&proto_tab_lock);
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 {
65         struct sock *sk;
66         struct pn_sock *pn;
67         struct phonet_protocol *pnp;
68         int err;
69
70         if (net != &init_net)
71                 return -EAFNOSUPPORT;
72
73         if (!capable(CAP_SYS_ADMIN))
74                 return -EPERM;
75
76         if (protocol == 0) {
77                 /* Default protocol selection */
78                 switch (sock->type) {
79                 case SOCK_DGRAM:
80                         protocol = PN_PROTO_PHONET;
81                         break;
82                 case SOCK_SEQPACKET:
83                         protocol = PN_PROTO_PIPE;
84                         break;
85                 default:
86                         return -EPROTONOSUPPORT;
87                 }
88         }
89
90         pnp = phonet_proto_get(protocol);
91         if (pnp == NULL &&
92             request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0)
93                 pnp = phonet_proto_get(protocol);
94
95         if (pnp == NULL)
96                 return -EPROTONOSUPPORT;
97         if (sock->type != pnp->sock_type) {
98                 err = -EPROTONOSUPPORT;
99                 goto out;
100         }
101
102         sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot);
103         if (sk == NULL) {
104                 err = -ENOMEM;
105                 goto out;
106         }
107
108         sock_init_data(sock, sk);
109         sock->state = SS_UNCONNECTED;
110         sock->ops = pnp->ops;
111         sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
112         sk->sk_protocol = protocol;
113         pn = pn_sk(sk);
114         pn->sobject = 0;
115         pn->resource = 0;
116         sk->sk_prot->init(sk);
117         err = 0;
118
119 out:
120         phonet_proto_put(pnp);
121         return err;
122 }
123
124 static struct net_proto_family phonet_proto_family = {
125         .family = PF_PHONET,
126         .create = pn_socket_create,
127         .owner = THIS_MODULE,
128 };
129
130 /* Phonet device header operations */
131 static int pn_header_create(struct sk_buff *skb, struct net_device *dev,
132                                 unsigned short type, const void *daddr,
133                                 const void *saddr, unsigned len)
134 {
135         u8 *media = skb_push(skb, 1);
136
137         if (type != ETH_P_PHONET)
138                 return -1;
139
140         if (!saddr)
141                 saddr = dev->dev_addr;
142         *media = *(const u8 *)saddr;
143         return 1;
144 }
145
146 static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr)
147 {
148         const u8 *media = skb_mac_header(skb);
149         *haddr = *media;
150         return 1;
151 }
152
153 struct header_ops phonet_header_ops = {
154         .create = pn_header_create,
155         .parse = pn_header_parse,
156 };
157 EXPORT_SYMBOL(phonet_header_ops);
158
159 /*
160  * Prepends an ISI header and sends a datagram.
161  */
162 static int pn_send(struct sk_buff *skb, struct net_device *dev,
163                         u16 dst, u16 src, u8 res, u8 irq)
164 {
165         struct phonethdr *ph;
166         int err;
167
168         if (skb->len + 2 > 0xffff /* Phonet length field limit */ ||
169             skb->len + sizeof(struct phonethdr) > dev->mtu) {
170                 err = -EMSGSIZE;
171                 goto drop;
172         }
173
174         skb_reset_transport_header(skb);
175         WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */
176         skb_push(skb, sizeof(struct phonethdr));
177         skb_reset_network_header(skb);
178         ph = pn_hdr(skb);
179         ph->pn_rdev = pn_dev(dst);
180         ph->pn_sdev = pn_dev(src);
181         ph->pn_res = res;
182         ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph));
183         ph->pn_robj = pn_obj(dst);
184         ph->pn_sobj = pn_obj(src);
185
186         skb->protocol = htons(ETH_P_PHONET);
187         skb->priority = 0;
188         skb->dev = dev;
189
190         if (pn_addr(src) == pn_addr(dst)) {
191                 skb_reset_mac_header(skb);
192                 skb->pkt_type = PACKET_LOOPBACK;
193                 skb_orphan(skb);
194                 if (irq)
195                         netif_rx(skb);
196                 else
197                         netif_rx_ni(skb);
198                 err = 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         }
208
209         return err;
210 drop:
211         kfree_skb(skb);
212         return err;
213 }
214
215 static int pn_raw_send(const void *data, int len, struct net_device *dev,
216                         u16 dst, u16 src, u8 res)
217 {
218         struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC);
219         if (skb == NULL)
220                 return -ENOMEM;
221
222         skb_reserve(skb, MAX_PHONET_HEADER);
223         __skb_put(skb, len);
224         skb_copy_to_linear_data(skb, data, len);
225         return pn_send(skb, dev, dst, src, res, 1);
226 }
227
228 /*
229  * Create a Phonet header for the skb and send it out. Returns
230  * non-zero error code if failed. The skb is freed then.
231  */
232 int pn_skb_send(struct sock *sk, struct sk_buff *skb,
233                 const struct sockaddr_pn *target)
234 {
235         struct net_device *dev;
236         struct pn_sock *pn = pn_sk(sk);
237         int err;
238         u16 src;
239         u8 daddr = pn_sockaddr_get_addr(target), saddr = PN_NO_ADDR;
240
241         err = -EHOSTUNREACH;
242         if (sk->sk_bound_dev_if)
243                 dev = dev_get_by_index(sock_net(sk), sk->sk_bound_dev_if);
244         else
245                 dev = phonet_device_get(sock_net(sk));
246         if (!dev || !(dev->flags & IFF_UP))
247                 goto drop;
248
249         saddr = phonet_address_get(dev, daddr);
250         if (saddr == PN_NO_ADDR)
251                 goto drop;
252
253         src = pn->sobject;
254         if (!pn_addr(src))
255                 src = pn_object(saddr, pn_obj(src));
256
257         err = pn_send(skb, dev, pn_sockaddr_get_object(target),
258                         src, pn_sockaddr_get_resource(target), 0);
259         dev_put(dev);
260         return err;
261
262 drop:
263         kfree_skb(skb);
264         if (dev)
265                 dev_put(dev);
266         return err;
267 }
268 EXPORT_SYMBOL(pn_skb_send);
269
270 /* Do not send an error message in response to an error message */
271 static inline int can_respond(struct sk_buff *skb)
272 {
273         const struct phonethdr *ph;
274         const struct phonetmsg *pm;
275         u8 submsg_id;
276
277         if (!pskb_may_pull(skb, 3))
278                 return 0;
279
280         ph = pn_hdr(skb);
281         if (phonet_address_get(skb->dev, ph->pn_rdev) != ph->pn_rdev)
282                 return 0; /* we are not the destination */
283         if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
284                 return 0;
285         if (ph->pn_res == PN_COMMGR) /* indications */
286                 return 0;
287
288         ph = pn_hdr(skb); /* re-acquires the pointer */
289         pm = pn_msg(skb);
290         if (pm->pn_msg_id != PN_COMMON_MESSAGE)
291                 return 1;
292         submsg_id = (ph->pn_res == PN_PREFIX)
293                 ? pm->pn_e_submsg_id : pm->pn_submsg_id;
294         if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
295                 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
296                 return 1;
297         return 0;
298 }
299
300 static int send_obj_unreachable(struct sk_buff *rskb)
301 {
302         const struct phonethdr *oph = pn_hdr(rskb);
303         const struct phonetmsg *opm = pn_msg(rskb);
304         struct phonetmsg resp;
305
306         memset(&resp, 0, sizeof(resp));
307         resp.pn_trans_id = opm->pn_trans_id;
308         resp.pn_msg_id = PN_COMMON_MESSAGE;
309         if (oph->pn_res == PN_PREFIX) {
310                 resp.pn_e_res_id = opm->pn_e_res_id;
311                 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
312                 resp.pn_e_orig_msg_id = opm->pn_msg_id;
313                 resp.pn_e_status = 0;
314         } else {
315                 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
316                 resp.pn_orig_msg_id = opm->pn_msg_id;
317                 resp.pn_status = 0;
318         }
319         return pn_raw_send(&resp, sizeof(resp), rskb->dev,
320                                 pn_object(oph->pn_sdev, oph->pn_sobj),
321                                 pn_object(oph->pn_rdev, oph->pn_robj),
322                                 oph->pn_res);
323 }
324
325 static int send_reset_indications(struct sk_buff *rskb)
326 {
327         struct phonethdr *oph = pn_hdr(rskb);
328         static const u8 data[4] = {
329                 0x00 /* trans ID */, 0x10 /* subscribe msg */,
330                 0x00 /* subscription count */, 0x00 /* dummy */
331         };
332
333         return pn_raw_send(data, sizeof(data), rskb->dev,
334                                 pn_object(oph->pn_sdev, 0x00),
335                                 pn_object(oph->pn_rdev, oph->pn_robj),
336                                 PN_COMMGR);
337 }
338
339
340 /* packet type functions */
341
342 /*
343  * Stuff received packets to associated sockets.
344  * On error, returns non-zero and releases the skb.
345  */
346 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
347                         struct packet_type *pkttype,
348                         struct net_device *orig_dev)
349 {
350         struct phonethdr *ph;
351         struct sock *sk;
352         struct sockaddr_pn sa;
353         u16 len;
354
355         if (dev_net(dev) != &init_net)
356                 goto out;
357
358         /* check we have at least a full Phonet header */
359         if (!pskb_pull(skb, sizeof(struct phonethdr)))
360                 goto out;
361
362         /* check that the advertised length is correct */
363         ph = pn_hdr(skb);
364         len = get_unaligned_be16(&ph->pn_length);
365         if (len < 2)
366                 goto out;
367         len -= 2;
368         if ((len > skb->len) || pskb_trim(skb, len))
369                 goto out;
370         skb_reset_transport_header(skb);
371
372         pn_skb_get_dst_sockaddr(skb, &sa);
373         if (pn_sockaddr_get_addr(&sa) == 0)
374                 goto out; /* currently, we cannot be device 0 */
375
376         sk = pn_find_sock_by_sa(&sa);
377         if (sk == NULL) {
378                 if (can_respond(skb)) {
379                         send_obj_unreachable(skb);
380                         send_reset_indications(skb);
381                 }
382                 goto out;
383         }
384
385         /* Push data to the socket (or other sockets connected to it). */
386         return sk_receive_skb(sk, skb, 0);
387
388 out:
389         kfree_skb(skb);
390         return NET_RX_DROP;
391 }
392
393 static struct packet_type phonet_packet_type = {
394         .type = __constant_htons(ETH_P_PHONET),
395         .dev = NULL,
396         .func = phonet_rcv,
397 };
398
399 int __init_or_module phonet_proto_register(int protocol,
400                                                 struct phonet_protocol *pp)
401 {
402         int err = 0;
403
404         if (protocol >= PHONET_NPROTO)
405                 return -EINVAL;
406
407         err = proto_register(pp->prot, 1);
408         if (err)
409                 return err;
410
411         spin_lock(&proto_tab_lock);
412         if (proto_tab[protocol])
413                 err = -EBUSY;
414         else
415                 proto_tab[protocol] = pp;
416         spin_unlock(&proto_tab_lock);
417
418         return err;
419 }
420 EXPORT_SYMBOL(phonet_proto_register);
421
422 void phonet_proto_unregister(int protocol, struct phonet_protocol *pp)
423 {
424         spin_lock(&proto_tab_lock);
425         BUG_ON(proto_tab[protocol] != pp);
426         proto_tab[protocol] = NULL;
427         spin_unlock(&proto_tab_lock);
428         proto_unregister(pp->prot);
429 }
430 EXPORT_SYMBOL(phonet_proto_unregister);
431
432 /* Module registration */
433 static int __init phonet_init(void)
434 {
435         int err;
436
437         err = sock_register(&phonet_proto_family);
438         if (err) {
439                 printk(KERN_ALERT
440                         "phonet protocol family initialization failed\n");
441                 return err;
442         }
443
444         phonet_device_init();
445         dev_add_pack(&phonet_packet_type);
446         phonet_netlink_register();
447         phonet_sysctl_init();
448
449         err = isi_register();
450         if (err)
451                 goto err;
452         return 0;
453
454 err:
455         phonet_sysctl_exit();
456         sock_unregister(PF_PHONET);
457         dev_remove_pack(&phonet_packet_type);
458         phonet_device_exit();
459         return err;
460 }
461
462 static void __exit phonet_exit(void)
463 {
464         isi_unregister();
465         phonet_sysctl_exit();
466         sock_unregister(PF_PHONET);
467         dev_remove_pack(&phonet_packet_type);
468         phonet_device_exit();
469 }
470
471 module_init(phonet_init);
472 module_exit(phonet_exit);
473 MODULE_DESCRIPTION("Phonet protocol stack for Linux");
474 MODULE_LICENSE("GPL");
475 MODULE_ALIAS_NETPROTO(PF_PHONET);