Phonet: Pipe End Point for Phonet Pipes protocol
[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 static struct net_proto_family phonet_proto_family;
37 static struct phonet_protocol *phonet_proto_get(int protocol);
38 static inline void phonet_proto_put(struct phonet_protocol *pp);
39
40 /* protocol family functions */
41
42 static int pn_socket_create(struct net *net, struct socket *sock, int protocol)
43 {
44         struct sock *sk;
45         struct pn_sock *pn;
46         struct phonet_protocol *pnp;
47         int err;
48
49         if (net != &init_net)
50                 return -EAFNOSUPPORT;
51
52         if (!capable(CAP_SYS_ADMIN))
53                 return -EPERM;
54
55         if (protocol == 0) {
56                 /* Default protocol selection */
57                 switch (sock->type) {
58                 case SOCK_DGRAM:
59                         protocol = PN_PROTO_PHONET;
60                         break;
61                 case SOCK_SEQPACKET:
62                         protocol = PN_PROTO_PIPE;
63                         break;
64                 default:
65                         return -EPROTONOSUPPORT;
66                 }
67         }
68
69         pnp = phonet_proto_get(protocol);
70 #ifdef CONFIG_KMOD
71         if (pnp == NULL &&
72             request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0)
73                 pnp = phonet_proto_get(protocol);
74 #endif
75         if (pnp == NULL)
76                 return -EPROTONOSUPPORT;
77         if (sock->type != pnp->sock_type) {
78                 err = -EPROTONOSUPPORT;
79                 goto out;
80         }
81
82         sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot);
83         if (sk == NULL) {
84                 err = -ENOMEM;
85                 goto out;
86         }
87
88         sock_init_data(sock, sk);
89         sock->state = SS_UNCONNECTED;
90         sock->ops = pnp->ops;
91         sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
92         sk->sk_protocol = protocol;
93         pn = pn_sk(sk);
94         pn->sobject = 0;
95         pn->resource = 0;
96         sk->sk_prot->init(sk);
97         err = 0;
98
99 out:
100         phonet_proto_put(pnp);
101         return err;
102 }
103
104 static struct net_proto_family phonet_proto_family = {
105         .family = PF_PHONET,
106         .create = pn_socket_create,
107         .owner = THIS_MODULE,
108 };
109
110 /* Phonet device header operations */
111 static int pn_header_create(struct sk_buff *skb, struct net_device *dev,
112                                 unsigned short type, const void *daddr,
113                                 const void *saddr, unsigned len)
114 {
115         u8 *media = skb_push(skb, 1);
116
117         if (type != ETH_P_PHONET)
118                 return -1;
119
120         if (!saddr)
121                 saddr = dev->dev_addr;
122         *media = *(const u8 *)saddr;
123         return 1;
124 }
125
126 static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr)
127 {
128         const u8 *media = skb_mac_header(skb);
129         *haddr = *media;
130         return 1;
131 }
132
133 struct header_ops phonet_header_ops = {
134         .create = pn_header_create,
135         .parse = pn_header_parse,
136 };
137 EXPORT_SYMBOL(phonet_header_ops);
138
139 /*
140  * Prepends an ISI header and sends a datagram.
141  */
142 static int pn_send(struct sk_buff *skb, struct net_device *dev,
143                         u16 dst, u16 src, u8 res, u8 irq)
144 {
145         struct phonethdr *ph;
146         int err;
147
148         if (skb->len + 2 > 0xffff) {
149                 /* Phonet length field would overflow */
150                 err = -EMSGSIZE;
151                 goto drop;
152         }
153
154         skb_reset_transport_header(skb);
155         WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */
156         skb_push(skb, sizeof(struct phonethdr));
157         skb_reset_network_header(skb);
158         ph = pn_hdr(skb);
159         ph->pn_rdev = pn_dev(dst);
160         ph->pn_sdev = pn_dev(src);
161         ph->pn_res = res;
162         ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph));
163         ph->pn_robj = pn_obj(dst);
164         ph->pn_sobj = pn_obj(src);
165
166         skb->protocol = htons(ETH_P_PHONET);
167         skb->priority = 0;
168         skb->dev = dev;
169
170         if (pn_addr(src) == pn_addr(dst)) {
171                 skb_reset_mac_header(skb);
172                 skb->pkt_type = PACKET_LOOPBACK;
173                 skb_orphan(skb);
174                 if (irq)
175                         netif_rx(skb);
176                 else
177                         netif_rx_ni(skb);
178                 err = 0;
179         } else {
180                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
181                                         NULL, NULL, skb->len);
182                 if (err < 0) {
183                         err = -EHOSTUNREACH;
184                         goto drop;
185                 }
186                 err = dev_queue_xmit(skb);
187         }
188
189         return err;
190 drop:
191         kfree_skb(skb);
192         return err;
193 }
194
195 static int pn_raw_send(const void *data, int len, struct net_device *dev,
196                         u16 dst, u16 src, u8 res)
197 {
198         struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC);
199         if (skb == NULL)
200                 return -ENOMEM;
201
202         skb_reserve(skb, MAX_PHONET_HEADER);
203         __skb_put(skb, len);
204         skb_copy_to_linear_data(skb, data, len);
205         return pn_send(skb, dev, dst, src, res, 1);
206 }
207
208 /*
209  * Create a Phonet header for the skb and send it out. Returns
210  * non-zero error code if failed. The skb is freed then.
211  */
212 int pn_skb_send(struct sock *sk, struct sk_buff *skb,
213                 const struct sockaddr_pn *target)
214 {
215         struct net_device *dev;
216         struct pn_sock *pn = pn_sk(sk);
217         int err;
218         u16 src;
219         u8 daddr = pn_sockaddr_get_addr(target), saddr = PN_NO_ADDR;
220
221         err = -EHOSTUNREACH;
222         if (sk->sk_bound_dev_if)
223                 dev = dev_get_by_index(sock_net(sk), sk->sk_bound_dev_if);
224         else
225                 dev = phonet_device_get(sock_net(sk));
226         if (!dev || !(dev->flags & IFF_UP))
227                 goto drop;
228
229         saddr = phonet_address_get(dev, daddr);
230         if (saddr == PN_NO_ADDR)
231                 goto drop;
232
233         src = pn->sobject;
234         if (!pn_addr(src))
235                 src = pn_object(saddr, pn_obj(src));
236
237         err = pn_send(skb, dev, pn_sockaddr_get_object(target),
238                         src, pn_sockaddr_get_resource(target), 0);
239         dev_put(dev);
240         return err;
241
242 drop:
243         kfree_skb(skb);
244         if (dev)
245                 dev_put(dev);
246         return err;
247 }
248 EXPORT_SYMBOL(pn_skb_send);
249
250 /* Do not send an error message in response to an error message */
251 static inline int can_respond(struct sk_buff *skb)
252 {
253         const struct phonethdr *ph;
254         const struct phonetmsg *pm;
255         u8 submsg_id;
256
257         if (!pskb_may_pull(skb, 3))
258                 return 0;
259
260         ph = pn_hdr(skb);
261         if (phonet_address_get(skb->dev, ph->pn_rdev) != ph->pn_rdev)
262                 return 0; /* we are not the destination */
263         if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
264                 return 0;
265
266         ph = pn_hdr(skb); /* re-acquires the pointer */
267         pm = pn_msg(skb);
268         if (pm->pn_msg_id != PN_COMMON_MESSAGE)
269                 return 1;
270         submsg_id = (ph->pn_res == PN_PREFIX)
271                 ? pm->pn_e_submsg_id : pm->pn_submsg_id;
272         if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
273                 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
274                 return 1;
275         return 0;
276 }
277
278 static int send_obj_unreachable(struct sk_buff *rskb)
279 {
280         const struct phonethdr *oph = pn_hdr(rskb);
281         const struct phonetmsg *opm = pn_msg(rskb);
282         struct phonetmsg resp;
283
284         memset(&resp, 0, sizeof(resp));
285         resp.pn_trans_id = opm->pn_trans_id;
286         resp.pn_msg_id = PN_COMMON_MESSAGE;
287         if (oph->pn_res == PN_PREFIX) {
288                 resp.pn_e_res_id = opm->pn_e_res_id;
289                 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
290                 resp.pn_e_orig_msg_id = opm->pn_msg_id;
291                 resp.pn_e_status = 0;
292         } else {
293                 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
294                 resp.pn_orig_msg_id = opm->pn_msg_id;
295                 resp.pn_status = 0;
296         }
297         return pn_raw_send(&resp, sizeof(resp), rskb->dev,
298                                 pn_object(oph->pn_sdev, oph->pn_sobj),
299                                 pn_object(oph->pn_rdev, oph->pn_robj),
300                                 oph->pn_res);
301 }
302
303 static int send_reset_indications(struct sk_buff *rskb)
304 {
305         struct phonethdr *oph = pn_hdr(rskb);
306         static const u8 data[4] = {
307                 0x00 /* trans ID */, 0x10 /* subscribe msg */,
308                 0x00 /* subscription count */, 0x00 /* dummy */
309         };
310
311         return pn_raw_send(data, sizeof(data), rskb->dev,
312                                 pn_object(oph->pn_sdev, 0x00),
313                                 pn_object(oph->pn_rdev, oph->pn_robj), 0x10);
314 }
315
316
317 /* packet type functions */
318
319 /*
320  * Stuff received packets to associated sockets.
321  * On error, returns non-zero and releases the skb.
322  */
323 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
324                         struct packet_type *pkttype,
325                         struct net_device *orig_dev)
326 {
327         struct phonethdr *ph;
328         struct sock *sk;
329         struct sockaddr_pn sa;
330         u16 len;
331
332         if (dev_net(dev) != &init_net)
333                 goto out;
334
335         /* check we have at least a full Phonet header */
336         if (!pskb_pull(skb, sizeof(struct phonethdr)))
337                 goto out;
338
339         /* check that the advertised length is correct */
340         ph = pn_hdr(skb);
341         len = get_unaligned_be16(&ph->pn_length);
342         if (len < 2)
343                 goto out;
344         len -= 2;
345         if ((len > skb->len) || pskb_trim(skb, len))
346                 goto out;
347         skb_reset_transport_header(skb);
348
349         pn_skb_get_dst_sockaddr(skb, &sa);
350         if (pn_sockaddr_get_addr(&sa) == 0)
351                 goto out; /* currently, we cannot be device 0 */
352
353         sk = pn_find_sock_by_sa(&sa);
354         if (sk == NULL) {
355                 if (can_respond(skb)) {
356                         send_obj_unreachable(skb);
357                         send_reset_indications(skb);
358                 }
359                 goto out;
360         }
361
362         /* Push data to the socket (or other sockets connected to it). */
363         return sk_receive_skb(sk, skb, 0);
364
365 out:
366         kfree_skb(skb);
367         return NET_RX_DROP;
368 }
369
370 static struct packet_type phonet_packet_type = {
371         .type = __constant_htons(ETH_P_PHONET),
372         .dev = NULL,
373         .func = phonet_rcv,
374 };
375
376 /* Transport protocol registration */
377 static struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
378 static DEFINE_SPINLOCK(proto_tab_lock);
379
380 int __init_or_module phonet_proto_register(int protocol,
381                                                 struct phonet_protocol *pp)
382 {
383         int err = 0;
384
385         if (protocol >= PHONET_NPROTO)
386                 return -EINVAL;
387
388         err = proto_register(pp->prot, 1);
389         if (err)
390                 return err;
391
392         spin_lock(&proto_tab_lock);
393         if (proto_tab[protocol])
394                 err = -EBUSY;
395         else
396                 proto_tab[protocol] = pp;
397         spin_unlock(&proto_tab_lock);
398
399         return err;
400 }
401 EXPORT_SYMBOL(phonet_proto_register);
402
403 void phonet_proto_unregister(int protocol, struct phonet_protocol *pp)
404 {
405         spin_lock(&proto_tab_lock);
406         BUG_ON(proto_tab[protocol] != pp);
407         proto_tab[protocol] = NULL;
408         spin_unlock(&proto_tab_lock);
409         proto_unregister(pp->prot);
410 }
411 EXPORT_SYMBOL(phonet_proto_unregister);
412
413 static struct phonet_protocol *phonet_proto_get(int protocol)
414 {
415         struct phonet_protocol *pp;
416
417         if (protocol >= PHONET_NPROTO)
418                 return NULL;
419
420         spin_lock(&proto_tab_lock);
421         pp = proto_tab[protocol];
422         if (pp && !try_module_get(pp->prot->owner))
423                 pp = NULL;
424         spin_unlock(&proto_tab_lock);
425
426         return pp;
427 }
428
429 static inline void phonet_proto_put(struct phonet_protocol *pp)
430 {
431         module_put(pp->prot->owner);
432 }
433
434 /* Module registration */
435 static int __init phonet_init(void)
436 {
437         int err;
438
439         err = sock_register(&phonet_proto_family);
440         if (err) {
441                 printk(KERN_ALERT
442                         "phonet protocol family initialization failed\n");
443                 return err;
444         }
445
446         phonet_device_init();
447         dev_add_pack(&phonet_packet_type);
448         phonet_netlink_register();
449         phonet_sysctl_init();
450
451         err = isi_register();
452         if (err)
453                 goto err;
454         return 0;
455
456 err:
457         phonet_sysctl_exit();
458         sock_unregister(PF_PHONET);
459         dev_remove_pack(&phonet_packet_type);
460         phonet_device_exit();
461         return err;
462 }
463
464 static void __exit phonet_exit(void)
465 {
466         isi_unregister();
467         phonet_sysctl_exit();
468         sock_unregister(PF_PHONET);
469         dev_remove_pack(&phonet_packet_type);
470         phonet_device_exit();
471 }
472
473 module_init(phonet_init);
474 module_exit(phonet_exit);
475 MODULE_DESCRIPTION("Phonet protocol stack for Linux");
476 MODULE_LICENSE("GPL");
477 MODULE_ALIAS_NETPROTO(PF_PHONET);