1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * File: af_phonet.c
4 *
5 * Phonet protocols family
6 *
7 * Copyright (C) 2008 Nokia Corporation.
8 *
9 * Authors: Sakari Ailus <sakari.ailus@nokia.com>
10 * Rémi Denis-Courmont
11 */
12
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <asm/unaligned.h>
17 #include <net/sock.h>
18
19 #include <linux/if_phonet.h>
20 #include <linux/phonet.h>
21 #include <net/phonet/phonet.h>
22 #include <net/phonet/pn_dev.h>
23
24 /* Transport protocol registration */
25 static const struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
26
phonet_proto_get(unsigned int protocol)27 static const struct phonet_protocol *phonet_proto_get(unsigned int protocol)
28 {
29 const struct phonet_protocol *pp;
30
31 if (protocol >= PHONET_NPROTO)
32 return NULL;
33
34 rcu_read_lock();
35 pp = rcu_dereference(proto_tab[protocol]);
36 if (pp && !try_module_get(pp->prot->owner))
37 pp = NULL;
38 rcu_read_unlock();
39
40 return pp;
41 }
42
phonet_proto_put(const struct phonet_protocol * pp)43 static inline void phonet_proto_put(const struct phonet_protocol *pp)
44 {
45 module_put(pp->prot->owner);
46 }
47
48 /* protocol family functions */
49
pn_socket_create(struct net * net,struct socket * sock,int protocol,int kern)50 static int pn_socket_create(struct net *net, struct socket *sock, int protocol,
51 int kern)
52 {
53 struct sock *sk;
54 struct pn_sock *pn;
55 const struct phonet_protocol *pnp;
56 int err;
57
58 if (!capable(CAP_SYS_ADMIN))
59 return -EPERM;
60
61 if (protocol == 0) {
62 /* Default protocol selection */
63 switch (sock->type) {
64 case SOCK_DGRAM:
65 protocol = PN_PROTO_PHONET;
66 break;
67 case SOCK_SEQPACKET:
68 protocol = PN_PROTO_PIPE;
69 break;
70 default:
71 return -EPROTONOSUPPORT;
72 }
73 }
74
75 pnp = phonet_proto_get(protocol);
76 if (pnp == NULL &&
77 request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0)
78 pnp = phonet_proto_get(protocol);
79
80 if (pnp == NULL)
81 return -EPROTONOSUPPORT;
82 if (sock->type != pnp->sock_type) {
83 err = -EPROTONOSUPPORT;
84 goto out;
85 }
86
87 sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot, kern);
88 if (sk == NULL) {
89 err = -ENOMEM;
90 goto out;
91 }
92
93 sock_init_data(sock, sk);
94 sock->state = SS_UNCONNECTED;
95 sock->ops = pnp->ops;
96 sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
97 sk->sk_protocol = protocol;
98 pn = pn_sk(sk);
99 pn->sobject = 0;
100 pn->dobject = 0;
101 pn->resource = 0;
102 sk->sk_prot->init(sk);
103 err = 0;
104
105 out:
106 phonet_proto_put(pnp);
107 return err;
108 }
109
110 static const struct net_proto_family phonet_proto_family = {
111 .family = PF_PHONET,
112 .create = pn_socket_create,
113 .owner = THIS_MODULE,
114 };
115
116 /* Phonet device header operations */
pn_header_create(struct sk_buff * skb,struct net_device * dev,unsigned short type,const void * daddr,const void * saddr,unsigned int len)117 static int pn_header_create(struct sk_buff *skb, struct net_device *dev,
118 unsigned short type, const void *daddr,
119 const void *saddr, unsigned int len)
120 {
121 u8 *media = skb_push(skb, 1);
122
123 if (type != ETH_P_PHONET)
124 return -1;
125
126 if (!saddr)
127 saddr = dev->dev_addr;
128 *media = *(const u8 *)saddr;
129 return 1;
130 }
131
pn_header_parse(const struct sk_buff * skb,unsigned char * haddr)132 static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr)
133 {
134 const u8 *media = skb_mac_header(skb);
135 *haddr = *media;
136 return 1;
137 }
138
139 const struct header_ops phonet_header_ops = {
140 .create = pn_header_create,
141 .parse = pn_header_parse,
142 };
143 EXPORT_SYMBOL(phonet_header_ops);
144
145 /*
146 * Prepends an ISI header and sends a datagram.
147 */
pn_send(struct sk_buff * skb,struct net_device * dev,u16 dst,u16 src,u8 res,u8 irq)148 static int pn_send(struct sk_buff *skb, struct net_device *dev,
149 u16 dst, u16 src, u8 res, u8 irq)
150 {
151 struct phonethdr *ph;
152 int err;
153
154 if (skb->len + 2 > 0xffff /* Phonet length field limit */ ||
155 skb->len + sizeof(struct phonethdr) > dev->mtu) {
156 err = -EMSGSIZE;
157 goto drop;
158 }
159
160 /* Broadcast sending is not implemented */
161 if (pn_addr(dst) == PNADDR_BROADCAST) {
162 err = -EOPNOTSUPP;
163 goto drop;
164 }
165
166 skb_reset_transport_header(skb);
167 WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */
168 skb_push(skb, sizeof(struct phonethdr));
169 skb_reset_network_header(skb);
170 ph = pn_hdr(skb);
171 ph->pn_rdev = pn_dev(dst);
172 ph->pn_sdev = pn_dev(src);
173 ph->pn_res = res;
174 ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph));
175 ph->pn_robj = pn_obj(dst);
176 ph->pn_sobj = pn_obj(src);
177
178 skb->protocol = htons(ETH_P_PHONET);
179 skb->priority = 0;
180 skb->dev = dev;
181
182 if (skb->pkt_type == PACKET_LOOPBACK) {
183 skb_reset_mac_header(skb);
184 skb_orphan(skb);
185 err = (irq ? netif_rx(skb) : netif_rx_ni(skb)) ? -ENOBUFS : 0;
186 } else {
187 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
188 NULL, NULL, skb->len);
189 if (err < 0) {
190 err = -EHOSTUNREACH;
191 goto drop;
192 }
193 err = dev_queue_xmit(skb);
194 if (unlikely(err > 0))
195 err = net_xmit_errno(err);
196 }
197
198 return err;
199 drop:
200 kfree_skb(skb);
201 return err;
202 }
203
pn_raw_send(const void * data,int len,struct net_device * dev,u16 dst,u16 src,u8 res)204 static int pn_raw_send(const void *data, int len, struct net_device *dev,
205 u16 dst, u16 src, u8 res)
206 {
207 struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC);
208 if (skb == NULL)
209 return -ENOMEM;
210
211 if (phonet_address_lookup(dev_net(dev), pn_addr(dst)) == 0)
212 skb->pkt_type = PACKET_LOOPBACK;
213
214 skb_reserve(skb, MAX_PHONET_HEADER);
215 __skb_put(skb, len);
216 skb_copy_to_linear_data(skb, data, len);
217 return pn_send(skb, dev, dst, src, res, 1);
218 }
219
220 /*
221 * Create a Phonet header for the skb and send it out. Returns
222 * non-zero error code if failed. The skb is freed then.
223 */
pn_skb_send(struct sock * sk,struct sk_buff * skb,const struct sockaddr_pn * target)224 int pn_skb_send(struct sock *sk, struct sk_buff *skb,
225 const struct sockaddr_pn *target)
226 {
227 struct net *net = sock_net(sk);
228 struct net_device *dev;
229 struct pn_sock *pn = pn_sk(sk);
230 int err;
231 u16 src, dst;
232 u8 daddr, saddr, res;
233
234 src = pn->sobject;
235 if (target != NULL) {
236 dst = pn_sockaddr_get_object(target);
237 res = pn_sockaddr_get_resource(target);
238 } else {
239 dst = pn->dobject;
240 res = pn->resource;
241 }
242 daddr = pn_addr(dst);
243
244 err = -EHOSTUNREACH;
245 if (sk->sk_bound_dev_if)
246 dev = dev_get_by_index(net, sk->sk_bound_dev_if);
247 else if (phonet_address_lookup(net, daddr) == 0) {
248 dev = phonet_device_get(net);
249 skb->pkt_type = PACKET_LOOPBACK;
250 } else if (dst == 0) {
251 /* Resource routing (small race until phonet_rcv()) */
252 struct sock *sk = pn_find_sock_by_res(net, res);
253 if (sk) {
254 sock_put(sk);
255 dev = phonet_device_get(net);
256 skb->pkt_type = PACKET_LOOPBACK;
257 } else
258 dev = phonet_route_output(net, daddr);
259 } else
260 dev = phonet_route_output(net, daddr);
261
262 if (!dev || !(dev->flags & IFF_UP))
263 goto drop;
264
265 saddr = phonet_address_get(dev, daddr);
266 if (saddr == PN_NO_ADDR)
267 goto drop;
268
269 if (!pn_addr(src))
270 src = pn_object(saddr, pn_obj(src));
271
272 err = pn_send(skb, dev, dst, src, res, 0);
273 dev_put(dev);
274 return err;
275
276 drop:
277 kfree_skb(skb);
278 if (dev)
279 dev_put(dev);
280 return err;
281 }
282 EXPORT_SYMBOL(pn_skb_send);
283
284 /* Do not send an error message in response to an error message */
can_respond(struct sk_buff * skb)285 static inline int can_respond(struct sk_buff *skb)
286 {
287 const struct phonethdr *ph;
288 const struct phonetmsg *pm;
289 u8 submsg_id;
290
291 if (!pskb_may_pull(skb, 3))
292 return 0;
293
294 ph = pn_hdr(skb);
295 if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
296 return 0;
297 if (ph->pn_res == PN_COMMGR) /* indications */
298 return 0;
299
300 ph = pn_hdr(skb); /* re-acquires the pointer */
301 pm = pn_msg(skb);
302 if (pm->pn_msg_id != PN_COMMON_MESSAGE)
303 return 1;
304 submsg_id = (ph->pn_res == PN_PREFIX)
305 ? pm->pn_e_submsg_id : pm->pn_submsg_id;
306 if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
307 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
308 return 1;
309 return 0;
310 }
311
send_obj_unreachable(struct sk_buff * rskb)312 static int send_obj_unreachable(struct sk_buff *rskb)
313 {
314 const struct phonethdr *oph = pn_hdr(rskb);
315 const struct phonetmsg *opm = pn_msg(rskb);
316 struct phonetmsg resp;
317
318 memset(&resp, 0, sizeof(resp));
319 resp.pn_trans_id = opm->pn_trans_id;
320 resp.pn_msg_id = PN_COMMON_MESSAGE;
321 if (oph->pn_res == PN_PREFIX) {
322 resp.pn_e_res_id = opm->pn_e_res_id;
323 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
324 resp.pn_e_orig_msg_id = opm->pn_msg_id;
325 resp.pn_e_status = 0;
326 } else {
327 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
328 resp.pn_orig_msg_id = opm->pn_msg_id;
329 resp.pn_status = 0;
330 }
331 return pn_raw_send(&resp, sizeof(resp), rskb->dev,
332 pn_object(oph->pn_sdev, oph->pn_sobj),
333 pn_object(oph->pn_rdev, oph->pn_robj),
334 oph->pn_res);
335 }
336
send_reset_indications(struct sk_buff * rskb)337 static int send_reset_indications(struct sk_buff *rskb)
338 {
339 struct phonethdr *oph = pn_hdr(rskb);
340 static const u8 data[4] = {
341 0x00 /* trans ID */, 0x10 /* subscribe msg */,
342 0x00 /* subscription count */, 0x00 /* dummy */
343 };
344
345 return pn_raw_send(data, sizeof(data), rskb->dev,
346 pn_object(oph->pn_sdev, 0x00),
347 pn_object(oph->pn_rdev, oph->pn_robj),
348 PN_COMMGR);
349 }
350
351
352 /* packet type functions */
353
354 /*
355 * Stuff received packets to associated sockets.
356 * On error, returns non-zero and releases the skb.
357 */
phonet_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * pkttype,struct net_device * orig_dev)358 static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
359 struct packet_type *pkttype,
360 struct net_device *orig_dev)
361 {
362 struct net *net = dev_net(dev);
363 struct phonethdr *ph;
364 struct sockaddr_pn sa;
365 u16 len;
366
367 skb = skb_share_check(skb, GFP_ATOMIC);
368 if (!skb)
369 return NET_RX_DROP;
370
371 /* check we have at least a full Phonet header */
372 if (!pskb_pull(skb, sizeof(struct phonethdr)))
373 goto out;
374
375 /* check that the advertised length is correct */
376 ph = pn_hdr(skb);
377 len = get_unaligned_be16(&ph->pn_length);
378 if (len < 2)
379 goto out;
380 len -= 2;
381 if ((len > skb->len) || pskb_trim(skb, len))
382 goto out;
383 skb_reset_transport_header(skb);
384
385 pn_skb_get_dst_sockaddr(skb, &sa);
386
387 /* check if this is broadcasted */
388 if (pn_sockaddr_get_addr(&sa) == PNADDR_BROADCAST) {
389 pn_deliver_sock_broadcast(net, skb);
390 goto out;
391 }
392
393 /* resource routing */
394 if (pn_sockaddr_get_object(&sa) == 0) {
395 struct sock *sk = pn_find_sock_by_res(net, sa.spn_resource);
396 if (sk)
397 return sk_receive_skb(sk, skb, 0);
398 }
399
400 /* check if we are the destination */
401 if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) {
402 /* Phonet packet input */
403 struct sock *sk = pn_find_sock_by_sa(net, &sa);
404
405 if (sk)
406 return sk_receive_skb(sk, skb, 0);
407
408 if (can_respond(skb)) {
409 send_obj_unreachable(skb);
410 send_reset_indications(skb);
411 }
412 } else if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
413 goto out; /* Race between address deletion and loopback */
414 else {
415 /* Phonet packet routing */
416 struct net_device *out_dev;
417
418 out_dev = phonet_route_output(net, pn_sockaddr_get_addr(&sa));
419 if (!out_dev) {
420 net_dbg_ratelimited("No Phonet route to %02X\n",
421 pn_sockaddr_get_addr(&sa));
422 goto out;
423 }
424
425 __skb_push(skb, sizeof(struct phonethdr));
426 skb->dev = out_dev;
427 if (out_dev == dev) {
428 net_dbg_ratelimited("Phonet loop to %02X on %s\n",
429 pn_sockaddr_get_addr(&sa),
430 dev->name);
431 goto out_dev;
432 }
433 /* Some drivers (e.g. TUN) do not allocate HW header space */
434 if (skb_cow_head(skb, out_dev->hard_header_len))
435 goto out_dev;
436
437 if (dev_hard_header(skb, out_dev, ETH_P_PHONET, NULL, NULL,
438 skb->len) < 0)
439 goto out_dev;
440 dev_queue_xmit(skb);
441 dev_put(out_dev);
442 return NET_RX_SUCCESS;
443 out_dev:
444 dev_put(out_dev);
445 }
446
447 out:
448 kfree_skb(skb);
449 return NET_RX_DROP;
450 }
451
452 static struct packet_type phonet_packet_type __read_mostly = {
453 .type = cpu_to_be16(ETH_P_PHONET),
454 .func = phonet_rcv,
455 };
456
457 static DEFINE_MUTEX(proto_tab_lock);
458
phonet_proto_register(unsigned int protocol,const struct phonet_protocol * pp)459 int __init_or_module phonet_proto_register(unsigned int protocol,
460 const struct phonet_protocol *pp)
461 {
462 int err = 0;
463
464 if (protocol >= PHONET_NPROTO)
465 return -EINVAL;
466
467 err = proto_register(pp->prot, 1);
468 if (err)
469 return err;
470
471 mutex_lock(&proto_tab_lock);
472 if (proto_tab[protocol])
473 err = -EBUSY;
474 else
475 rcu_assign_pointer(proto_tab[protocol], pp);
476 mutex_unlock(&proto_tab_lock);
477
478 return err;
479 }
480 EXPORT_SYMBOL(phonet_proto_register);
481
phonet_proto_unregister(unsigned int protocol,const struct phonet_protocol * pp)482 void phonet_proto_unregister(unsigned int protocol,
483 const struct phonet_protocol *pp)
484 {
485 mutex_lock(&proto_tab_lock);
486 BUG_ON(proto_tab[protocol] != pp);
487 RCU_INIT_POINTER(proto_tab[protocol], NULL);
488 mutex_unlock(&proto_tab_lock);
489 synchronize_rcu();
490 proto_unregister(pp->prot);
491 }
492 EXPORT_SYMBOL(phonet_proto_unregister);
493
494 /* Module registration */
phonet_init(void)495 static int __init phonet_init(void)
496 {
497 int err;
498
499 err = phonet_device_init();
500 if (err)
501 return err;
502
503 pn_sock_init();
504 err = sock_register(&phonet_proto_family);
505 if (err) {
506 printk(KERN_ALERT
507 "phonet protocol family initialization failed\n");
508 goto err_sock;
509 }
510
511 dev_add_pack(&phonet_packet_type);
512 phonet_sysctl_init();
513
514 err = isi_register();
515 if (err)
516 goto err;
517 return 0;
518
519 err:
520 phonet_sysctl_exit();
521 sock_unregister(PF_PHONET);
522 dev_remove_pack(&phonet_packet_type);
523 err_sock:
524 phonet_device_exit();
525 return err;
526 }
527
phonet_exit(void)528 static void __exit phonet_exit(void)
529 {
530 isi_unregister();
531 phonet_sysctl_exit();
532 sock_unregister(PF_PHONET);
533 dev_remove_pack(&phonet_packet_type);
534 phonet_device_exit();
535 }
536
537 module_init(phonet_init);
538 module_exit(phonet_exit);
539 MODULE_DESCRIPTION("Phonet protocol stack for Linux");
540 MODULE_LICENSE("GPL");
541 MODULE_ALIAS_NETPROTO(PF_PHONET);
542