Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[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
39 static inline void phonet_proto_put(struct phonet_protocol *pp)
40 {
41         module_put(pp->prot->owner);
42 }
43
44 /* protocol family functions */
45
46 static int pn_socket_create(struct net *net, struct socket *sock, int protocol)
47 {
48         struct sock *sk;
49         struct pn_sock *pn;
50         struct phonet_protocol *pnp;
51         int err;
52
53         if (net != &init_net)
54                 return -EAFNOSUPPORT;
55
56         if (!capable(CAP_SYS_ADMIN))
57                 return -EPERM;
58
59         if (protocol == 0) {
60                 /* Default protocol selection */
61                 switch (sock->type) {
62                 case SOCK_DGRAM:
63                         protocol = PN_PROTO_PHONET;
64                         break;
65                 case SOCK_SEQPACKET:
66                         protocol = PN_PROTO_PIPE;
67                         break;
68                 default:
69                         return -EPROTONOSUPPORT;
70                 }
71         }
72
73         pnp = phonet_proto_get(protocol);
74         if (pnp == NULL &&
75             request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0)
76                 pnp = phonet_proto_get(protocol);
77
78         if (pnp == NULL)
79                 return -EPROTONOSUPPORT;
80         if (sock->type != pnp->sock_type) {
81                 err = -EPROTONOSUPPORT;
82                 goto out;
83         }
84
85         sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot);
86         if (sk == NULL) {
87                 err = -ENOMEM;
88                 goto out;
89         }
90
91         sock_init_data(sock, sk);
92         sock->state = SS_UNCONNECTED;
93         sock->ops = pnp->ops;
94         sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
95         sk->sk_protocol = protocol;
96         pn = pn_sk(sk);
97         pn->sobject = 0;
98         pn->resource = 0;
99         sk->sk_prot->init(sk);
100         err = 0;
101
102 out:
103         phonet_proto_put(pnp);
104         return err;
105 }
106
107 static struct net_proto_family phonet_proto_family = {
108         .family = PF_PHONET,
109         .create = pn_socket_create,
110         .owner = THIS_MODULE,
111 };
112
113 /* Phonet device header operations */
114 static int pn_header_create(struct sk_buff *skb, struct net_device *dev,
115                                 unsigned short type, const void *daddr,
116                                 const void *saddr, unsigned len)
117 {
118         u8 *media = skb_push(skb, 1);
119
120         if (type != ETH_P_PHONET)
121                 return -1;
122
123         if (!saddr)
124                 saddr = dev->dev_addr;
125         *media = *(const u8 *)saddr;
126         return 1;
127 }
128
129 static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr)
130 {
131         const u8 *media = skb_mac_header(skb);
132         *haddr = *media;
133         return 1;
134 }
135
136 struct header_ops phonet_header_ops = {
137         .create = pn_header_create,
138         .parse = pn_header_parse,
139 };
140 EXPORT_SYMBOL(phonet_header_ops);
141
142 /*
143  * Prepends an ISI header and sends a datagram.
144  */
145 static int pn_send(struct sk_buff *skb, struct net_device *dev,
146                         u16 dst, u16 src, u8 res, u8 irq)
147 {
148         struct phonethdr *ph;
149         int err;
150
151         if (skb->len + 2 > 0xffff /* Phonet length field limit */ ||
152             skb->len + sizeof(struct phonethdr) > dev->mtu) {
153                 err = -EMSGSIZE;
154                 goto drop;
155         }
156
157         skb_reset_transport_header(skb);
158         WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */
159         skb_push(skb, sizeof(struct phonethdr));
160         skb_reset_network_header(skb);
161         ph = pn_hdr(skb);
162         ph->pn_rdev = pn_dev(dst);
163         ph->pn_sdev = pn_dev(src);
164         ph->pn_res = res;
165         ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph));
166         ph->pn_robj = pn_obj(dst);
167         ph->pn_sobj = pn_obj(src);
168
169         skb->protocol = htons(ETH_P_PHONET);
170         skb->priority = 0;
171         skb->dev = dev;
172
173         if (pn_addr(src) == pn_addr(dst)) {
174                 skb_reset_mac_header(skb);
175                 skb->pkt_type = PACKET_LOOPBACK;
176                 skb_orphan(skb);
177                 if (irq)
178                         netif_rx(skb);
179                 else
180                         netif_rx_ni(skb);
181                 err = 0;
182         } else {
183                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
184                                         NULL, NULL, skb->len);
185                 if (err < 0) {
186                         err = -EHOSTUNREACH;
187                         goto drop;
188                 }
189                 err = dev_queue_xmit(skb);
190         }
191
192         return err;
193 drop:
194         kfree_skb(skb);
195         return err;
196 }
197
198 static int pn_raw_send(const void *data, int len, struct net_device *dev,
199                         u16 dst, u16 src, u8 res)
200 {
201         struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC);
202         if (skb == NULL)
203                 return -ENOMEM;
204
205         skb_reserve(skb, MAX_PHONET_HEADER);
206         __skb_put(skb, len);
207         skb_copy_to_linear_data(skb, data, len);
208         return pn_send(skb, dev, dst, src, res, 1);
209 }
210
211 /*
212  * Create a Phonet header for the skb and send it out. Returns
213  * non-zero error code if failed. The skb is freed then.
214  */
215 int pn_skb_send(struct sock *sk, struct sk_buff *skb,
216                 const struct sockaddr_pn *target)
217 {
218         struct net_device *dev;
219         struct pn_sock *pn = pn_sk(sk);
220         int err;
221         u16 src;
222         u8 daddr = pn_sockaddr_get_addr(target), saddr = PN_NO_ADDR;
223
224         err = -EHOSTUNREACH;
225         if (sk->sk_bound_dev_if)
226                 dev = dev_get_by_index(sock_net(sk), sk->sk_bound_dev_if);
227         else
228                 dev = phonet_device_get(sock_net(sk));
229         if (!dev || !(dev->flags & IFF_UP))
230                 goto drop;
231
232         saddr = phonet_address_get(dev, daddr);
233         if (saddr == PN_NO_ADDR)
234                 goto drop;
235
236         src = pn->sobject;
237         if (!pn_addr(src))
238                 src = pn_object(saddr, pn_obj(src));
239
240         err = pn_send(skb, dev, pn_sockaddr_get_object(target),
241                         src, pn_sockaddr_get_resource(target), 0);
242         dev_put(dev);
243         return err;
244
245 drop:
246         kfree_skb(skb);
247         if (dev)
248                 dev_put(dev);
249         return err;
250 }
251 EXPORT_SYMBOL(pn_skb_send);
252
253 /* Do not send an error message in response to an error message */
254 static inline int can_respond(struct sk_buff *skb)
255 {
256         const struct phonethdr *ph;
257         const struct phonetmsg *pm;
258         u8 submsg_id;
259
260         if (!pskb_may_pull(skb, 3))
261                 return 0;
262
263         ph = pn_hdr(skb);
264         if (phonet_address_get(skb->dev, ph->pn_rdev) != ph->pn_rdev)
265                 return 0; /* we are not the destination */
266         if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
267                 return 0;
268         if (ph->pn_res == PN_COMMGR) /* indications */
269                 return 0;
270
271         ph = pn_hdr(skb); /* re-acquires the pointer */
272         pm = pn_msg(skb);
273         if (pm->pn_msg_id != PN_COMMON_MESSAGE)
274                 return 1;
275         submsg_id = (ph->pn_res == PN_PREFIX)
276                 ? pm->pn_e_submsg_id : pm->pn_submsg_id;
277         if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
278                 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
279                 return 1;
280         return 0;
281 }
282
283 static int send_obj_unreachable(struct sk_buff *rskb)
284 {
285         const struct phonethdr *oph = pn_hdr(rskb);
286         const struct phonetmsg *opm = pn_msg(rskb);
287         struct phonetmsg resp;
288
289         memset(&resp, 0, sizeof(resp));
290         resp.pn_trans_id = opm->pn_trans_id;
291         resp.pn_msg_id = PN_COMMON_MESSAGE;
292         if (oph->pn_res == PN_PREFIX) {
293                 resp.pn_e_res_id = opm->pn_e_res_id;
294                 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
295                 resp.pn_e_orig_msg_id = opm->pn_msg_id;
296                 resp.pn_e_status = 0;
297         } else {
298                 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
299                 resp.pn_orig_msg_id = opm->pn_msg_id;
300                 resp.pn_status = 0;
301         }
302         return pn_raw_send(&resp, sizeof(resp), rskb->dev,
303                                 pn_object(oph->pn_sdev, oph->pn_sobj),
304                                 pn_object(oph->pn_rdev, oph->pn_robj),
305                                 oph->pn_res);
306 }
307
308 static int send_reset_indications(struct sk_buff *rskb)
309 {
310         struct phonethdr *oph = pn_hdr(rskb);
311         static const u8 data[4] = {
312                 0x00 /* trans ID */, 0x10 /* subscribe msg */,
313                 0x00 /* subscription count */, 0x00 /* dummy */
314         };
315
316         return pn_raw_send(data, sizeof(data), rskb->dev,
317                                 pn_object(oph->pn_sdev, 0x00),
318                                 pn_object(oph->pn_rdev, oph->pn_robj),
319                                 PN_COMMGR);
320 }
321
322
323 /* packet type functions */
324
325 /*
326  * Stuff received packets to associated sockets.
327  * On error, returns non-zero and releases the skb.
328  */
329 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
330                         struct packet_type *pkttype,
331                         struct net_device *orig_dev)
332 {
333         struct phonethdr *ph;
334         struct sock *sk;
335         struct sockaddr_pn sa;
336         u16 len;
337
338         if (dev_net(dev) != &init_net)
339                 goto out;
340
341         /* check we have at least a full Phonet header */
342         if (!pskb_pull(skb, sizeof(struct phonethdr)))
343                 goto out;
344
345         /* check that the advertised length is correct */
346         ph = pn_hdr(skb);
347         len = get_unaligned_be16(&ph->pn_length);
348         if (len < 2)
349                 goto out;
350         len -= 2;
351         if ((len > skb->len) || pskb_trim(skb, len))
352                 goto out;
353         skb_reset_transport_header(skb);
354
355         pn_skb_get_dst_sockaddr(skb, &sa);
356         if (pn_sockaddr_get_addr(&sa) == 0)
357                 goto out; /* currently, we cannot be device 0 */
358
359         sk = pn_find_sock_by_sa(&sa);
360         if (sk == NULL) {
361                 if (can_respond(skb)) {
362                         send_obj_unreachable(skb);
363                         send_reset_indications(skb);
364                 }
365                 goto out;
366         }
367
368         /* Push data to the socket (or other sockets connected to it). */
369         return sk_receive_skb(sk, skb, 0);
370
371 out:
372         kfree_skb(skb);
373         return NET_RX_DROP;
374 }
375
376 static struct packet_type phonet_packet_type = {
377         .type = __constant_htons(ETH_P_PHONET),
378         .dev = NULL,
379         .func = phonet_rcv,
380 };
381
382 /* Transport protocol registration */
383 static struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
384 static DEFINE_SPINLOCK(proto_tab_lock);
385
386 int __init_or_module phonet_proto_register(int protocol,
387                                                 struct phonet_protocol *pp)
388 {
389         int err = 0;
390
391         if (protocol >= PHONET_NPROTO)
392                 return -EINVAL;
393
394         err = proto_register(pp->prot, 1);
395         if (err)
396                 return err;
397
398         spin_lock(&proto_tab_lock);
399         if (proto_tab[protocol])
400                 err = -EBUSY;
401         else
402                 proto_tab[protocol] = pp;
403         spin_unlock(&proto_tab_lock);
404
405         return err;
406 }
407 EXPORT_SYMBOL(phonet_proto_register);
408
409 void phonet_proto_unregister(int protocol, struct phonet_protocol *pp)
410 {
411         spin_lock(&proto_tab_lock);
412         BUG_ON(proto_tab[protocol] != pp);
413         proto_tab[protocol] = NULL;
414         spin_unlock(&proto_tab_lock);
415         proto_unregister(pp->prot);
416 }
417 EXPORT_SYMBOL(phonet_proto_unregister);
418
419 static struct phonet_protocol *phonet_proto_get(int protocol)
420 {
421         struct phonet_protocol *pp;
422
423         if (protocol >= PHONET_NPROTO)
424                 return NULL;
425
426         spin_lock(&proto_tab_lock);
427         pp = proto_tab[protocol];
428         if (pp && !try_module_get(pp->prot->owner))
429                 pp = NULL;
430         spin_unlock(&proto_tab_lock);
431
432         return pp;
433 }
434
435 /* Module registration */
436 static int __init phonet_init(void)
437 {
438         int err;
439
440         err = sock_register(&phonet_proto_family);
441         if (err) {
442                 printk(KERN_ALERT
443                         "phonet protocol family initialization failed\n");
444                 return err;
445         }
446
447         phonet_device_init();
448         dev_add_pack(&phonet_packet_type);
449         phonet_netlink_register();
450         phonet_sysctl_init();
451
452         err = isi_register();
453         if (err)
454                 goto err;
455         return 0;
456
457 err:
458         phonet_sysctl_exit();
459         sock_unregister(PF_PHONET);
460         dev_remove_pack(&phonet_packet_type);
461         phonet_device_exit();
462         return err;
463 }
464
465 static void __exit phonet_exit(void)
466 {
467         isi_unregister();
468         phonet_sysctl_exit();
469         sock_unregister(PF_PHONET);
470         dev_remove_pack(&phonet_packet_type);
471         phonet_device_exit();
472 }
473
474 module_init(phonet_init);
475 module_exit(phonet_exit);
476 MODULE_DESCRIPTION("Phonet protocol stack for Linux");
477 MODULE_LICENSE("GPL");
478 MODULE_ALIAS_NETPROTO(PF_PHONET);