bridge: Have tx_bytes count headers like rx_bytes.
[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(unsigned 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->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 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 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         /* check we have at least a full Phonet header */
381         if (!pskb_pull(skb, sizeof(struct phonethdr)))
382                 goto out;
383
384         /* check that the advertised length is correct */
385         ph = pn_hdr(skb);
386         len = get_unaligned_be16(&ph->pn_length);
387         if (len < 2)
388                 goto out;
389         len -= 2;
390         if ((len > skb->len) || pskb_trim(skb, len))
391                 goto out;
392         skb_reset_transport_header(skb);
393
394         pn_skb_get_dst_sockaddr(skb, &sa);
395
396         /* check if this is broadcasted */
397         if (pn_sockaddr_get_addr(&sa) == PNADDR_BROADCAST) {
398                 pn_deliver_sock_broadcast(net, skb);
399                 goto out;
400         }
401
402         /* resource routing */
403         if (pn_sockaddr_get_object(&sa) == 0) {
404                 struct sock *sk = pn_find_sock_by_res(net, sa.spn_resource);
405                 if (sk)
406                         return sk_receive_skb(sk, skb, 0);
407         }
408
409         /* check if we are the destination */
410         if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) {
411                 /* Phonet packet input */
412                 struct sock *sk = pn_find_sock_by_sa(net, &sa);
413
414                 if (sk)
415                         return sk_receive_skb(sk, skb, 0);
416
417                 if (can_respond(skb)) {
418                         send_obj_unreachable(skb);
419                         send_reset_indications(skb);
420                 }
421         } else if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
422                 goto out; /* Race between address deletion and loopback */
423         else {
424                 /* Phonet packet routing */
425                 struct net_device *out_dev;
426
427                 out_dev = phonet_route_output(net, pn_sockaddr_get_addr(&sa));
428                 if (!out_dev) {
429                         LIMIT_NETDEBUG(KERN_WARNING"No Phonet route to %02X\n",
430                                         pn_sockaddr_get_addr(&sa));
431                         goto out;
432                 }
433
434                 __skb_push(skb, sizeof(struct phonethdr));
435                 skb->dev = out_dev;
436                 if (out_dev == dev) {
437                         LIMIT_NETDEBUG(KERN_ERR"Phonet loop to %02X on %s\n",
438                                         pn_sockaddr_get_addr(&sa), dev->name);
439                         goto out_dev;
440                 }
441                 /* Some drivers (e.g. TUN) do not allocate HW header space */
442                 if (skb_cow_head(skb, out_dev->hard_header_len))
443                         goto out_dev;
444
445                 if (dev_hard_header(skb, out_dev, ETH_P_PHONET, NULL, NULL,
446                                         skb->len) < 0)
447                         goto out_dev;
448                 dev_queue_xmit(skb);
449                 dev_put(out_dev);
450                 return NET_RX_SUCCESS;
451 out_dev:
452                 dev_put(out_dev);
453         }
454
455 out:
456         kfree_skb(skb);
457         return NET_RX_DROP;
458 }
459
460 static struct packet_type phonet_packet_type __read_mostly = {
461         .type = cpu_to_be16(ETH_P_PHONET),
462         .func = phonet_rcv,
463 };
464
465 static DEFINE_MUTEX(proto_tab_lock);
466
467 int __init_or_module phonet_proto_register(unsigned int protocol,
468                                                 struct phonet_protocol *pp)
469 {
470         int err = 0;
471
472         if (protocol >= PHONET_NPROTO)
473                 return -EINVAL;
474
475         err = proto_register(pp->prot, 1);
476         if (err)
477                 return err;
478
479         mutex_lock(&proto_tab_lock);
480         if (proto_tab[protocol])
481                 err = -EBUSY;
482         else
483                 rcu_assign_pointer(proto_tab[protocol], pp);
484         mutex_unlock(&proto_tab_lock);
485
486         return err;
487 }
488 EXPORT_SYMBOL(phonet_proto_register);
489
490 void phonet_proto_unregister(unsigned int protocol, struct phonet_protocol *pp)
491 {
492         mutex_lock(&proto_tab_lock);
493         BUG_ON(proto_tab[protocol] != pp);
494         rcu_assign_pointer(proto_tab[protocol], NULL);
495         mutex_unlock(&proto_tab_lock);
496         synchronize_rcu();
497         proto_unregister(pp->prot);
498 }
499 EXPORT_SYMBOL(phonet_proto_unregister);
500
501 /* Module registration */
502 static int __init phonet_init(void)
503 {
504         int err;
505
506         err = phonet_device_init();
507         if (err)
508                 return err;
509
510         pn_sock_init();
511         err = sock_register(&phonet_proto_family);
512         if (err) {
513                 printk(KERN_ALERT
514                         "phonet protocol family initialization failed\n");
515                 goto err_sock;
516         }
517
518         dev_add_pack(&phonet_packet_type);
519         phonet_sysctl_init();
520
521         err = isi_register();
522         if (err)
523                 goto err;
524         return 0;
525
526 err:
527         phonet_sysctl_exit();
528         sock_unregister(PF_PHONET);
529         dev_remove_pack(&phonet_packet_type);
530 err_sock:
531         phonet_device_exit();
532         return err;
533 }
534
535 static void __exit phonet_exit(void)
536 {
537         isi_unregister();
538         phonet_sysctl_exit();
539         sock_unregister(PF_PHONET);
540         dev_remove_pack(&phonet_packet_type);
541         phonet_device_exit();
542 }
543
544 module_init(phonet_init);
545 module_exit(phonet_exit);
546 MODULE_DESCRIPTION("Phonet protocol stack for Linux");
547 MODULE_LICENSE("GPL");
548 MODULE_ALIAS_NETPROTO(PF_PHONET);