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 */
25static const struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
26
27static 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(module: pp->prot->owner))
37 pp = NULL;
38 rcu_read_unlock();
39
40 return pp;
41}
42
43static inline void phonet_proto_put(const struct phonet_protocol *pp)
44{
45 module_put(module: pp->prot->owner);
46}
47
48/* protocol family functions */
49
50static 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, prot: 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
105out:
106 phonet_proto_put(pp: pnp);
107 return err;
108}
109
110static 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 */
117static 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, len: 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
132static 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
139const struct header_ops phonet_header_ops = {
140 .create = pn_header_create,
141 .parse = pn_header_parse,
142};
143EXPORT_SYMBOL(phonet_header_ops);
144
145/*
146 * Prepends an ISI header and sends a datagram.
147 */
148static int pn_send(struct sk_buff *skb, struct net_device *dev,
149 u16 dst, u16 src, u8 res)
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(handle: 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, len: sizeof(struct phonethdr));
169 skb_reset_network_header(skb);
170 ph = pn_hdr(skb);
171 ph->pn_rdev = pn_dev(handle: dst);
172 ph->pn_sdev = pn_dev(handle: src);
173 ph->pn_res = res;
174 ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph));
175 ph->pn_robj = pn_obj(handle: dst);
176 ph->pn_sobj = pn_obj(handle: 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 = netif_rx(skb) ? -ENOBUFS : 0;
186 } else {
187 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
188 NULL, NULL, len: 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;
199drop:
200 kfree_skb(skb);
201 return err;
202}
203
204static 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(net: dev_net(dev), addr: pn_addr(handle: 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, from: data, len);
217 return pn_send(skb, dev, dst, src, res);
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 */
224int 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(spn: target);
237 res = pn_sockaddr_get_resource(spn: target);
238 } else {
239 dst = pn->dobject;
240 res = pn->resource;
241 }
242 daddr = pn_addr(handle: dst);
243
244 err = -EHOSTUNREACH;
245 if (sk->sk_bound_dev_if)
246 dev = dev_get_by_index(net, ifindex: sk->sk_bound_dev_if);
247 else if (phonet_address_lookup(net, addr: 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, addr: daddr);
266 if (saddr == PN_NO_ADDR)
267 goto drop;
268
269 if (!pn_addr(handle: src))
270 src = pn_object(addr: saddr, port: pn_obj(handle: src));
271
272 err = pn_send(skb, dev, dst, src, res);
273 dev_put(dev);
274 return err;
275
276drop:
277 kfree_skb(skb);
278 dev_put(dev);
279 return err;
280}
281EXPORT_SYMBOL(pn_skb_send);
282
283/* Do not send an error message in response to an error message */
284static inline int can_respond(struct sk_buff *skb)
285{
286 const struct phonethdr *ph;
287 const struct phonetmsg *pm;
288 u8 submsg_id;
289
290 if (!pskb_may_pull(skb, len: 3))
291 return 0;
292
293 ph = pn_hdr(skb);
294 if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, len: 5))
295 return 0;
296 if (ph->pn_res == PN_COMMGR) /* indications */
297 return 0;
298
299 ph = pn_hdr(skb); /* re-acquires the pointer */
300 pm = pn_msg(skb);
301 if (pm->pn_msg_id != PN_COMMON_MESSAGE)
302 return 1;
303 submsg_id = (ph->pn_res == PN_PREFIX)
304 ? pm->pn_e_submsg_id : pm->pn_submsg_id;
305 if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
306 pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
307 return 1;
308 return 0;
309}
310
311static int send_obj_unreachable(struct sk_buff *rskb)
312{
313 const struct phonethdr *oph = pn_hdr(skb: rskb);
314 const struct phonetmsg *opm = pn_msg(skb: rskb);
315 struct phonetmsg resp;
316
317 memset(&resp, 0, sizeof(resp));
318 resp.pn_trans_id = opm->pn_trans_id;
319 resp.pn_msg_id = PN_COMMON_MESSAGE;
320 if (oph->pn_res == PN_PREFIX) {
321 resp.pn_e_res_id = opm->pn_e_res_id;
322 resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
323 resp.pn_e_orig_msg_id = opm->pn_msg_id;
324 resp.pn_e_status = 0;
325 } else {
326 resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
327 resp.pn_orig_msg_id = opm->pn_msg_id;
328 resp.pn_status = 0;
329 }
330 return pn_raw_send(data: &resp, len: sizeof(resp), dev: rskb->dev,
331 dst: pn_object(addr: oph->pn_sdev, port: oph->pn_sobj),
332 src: pn_object(addr: oph->pn_rdev, port: oph->pn_robj),
333 res: oph->pn_res);
334}
335
336static int send_reset_indications(struct sk_buff *rskb)
337{
338 struct phonethdr *oph = pn_hdr(skb: rskb);
339 static const u8 data[4] = {
340 0x00 /* trans ID */, 0x10 /* subscribe msg */,
341 0x00 /* subscription count */, 0x00 /* dummy */
342 };
343
344 return pn_raw_send(data, len: sizeof(data), dev: rskb->dev,
345 dst: pn_object(addr: oph->pn_sdev, port: 0x00),
346 src: pn_object(addr: oph->pn_rdev, port: oph->pn_robj),
347 PN_COMMGR);
348}
349
350
351/* packet type functions */
352
353/*
354 * Stuff received packets to associated sockets.
355 * On error, returns non-zero and releases the skb.
356 */
357static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
358 struct packet_type *pkttype,
359 struct net_device *orig_dev)
360{
361 struct net *net = dev_net(dev);
362 struct phonethdr *ph;
363 struct sockaddr_pn sa;
364 u16 len;
365
366 skb = skb_share_check(skb, GFP_ATOMIC);
367 if (!skb)
368 return NET_RX_DROP;
369
370 /* check we have at least a full Phonet header */
371 if (!pskb_pull(skb, len: sizeof(struct phonethdr)))
372 goto out;
373
374 /* check that the advertised length is correct */
375 ph = pn_hdr(skb);
376 len = get_unaligned_be16(p: &ph->pn_length);
377 if (len < 2)
378 goto out;
379 len -= 2;
380 if ((len > skb->len) || pskb_trim(skb, len))
381 goto out;
382 skb_reset_transport_header(skb);
383
384 pn_skb_get_dst_sockaddr(skb, sa: &sa);
385
386 /* check if this is broadcasted */
387 if (pn_sockaddr_get_addr(spn: &sa) == PNADDR_BROADCAST) {
388 pn_deliver_sock_broadcast(net, skb);
389 goto out;
390 }
391
392 /* resource routing */
393 if (pn_sockaddr_get_object(spn: &sa) == 0) {
394 struct sock *sk = pn_find_sock_by_res(net, res: sa.spn_resource);
395 if (sk)
396 return sk_receive_skb(sk, skb, nested: 0);
397 }
398
399 /* check if we are the destination */
400 if (phonet_address_lookup(net, addr: pn_sockaddr_get_addr(spn: &sa)) == 0) {
401 /* Phonet packet input */
402 struct sock *sk = pn_find_sock_by_sa(net, sa: &sa);
403
404 if (sk)
405 return sk_receive_skb(sk, skb, nested: 0);
406
407 if (can_respond(skb)) {
408 send_obj_unreachable(rskb: skb);
409 send_reset_indications(rskb: skb);
410 }
411 } else if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
412 goto out; /* Race between address deletion and loopback */
413 else {
414 /* Phonet packet routing */
415 struct net_device *out_dev;
416
417 out_dev = phonet_route_output(net, daddr: pn_sockaddr_get_addr(spn: &sa));
418 if (!out_dev) {
419 net_dbg_ratelimited("No Phonet route to %02X\n",
420 pn_sockaddr_get_addr(&sa));
421 goto out;
422 }
423
424 __skb_push(skb, len: sizeof(struct phonethdr));
425 skb->dev = out_dev;
426 if (out_dev == dev) {
427 net_dbg_ratelimited("Phonet loop to %02X on %s\n",
428 pn_sockaddr_get_addr(&sa),
429 dev->name);
430 goto out_dev;
431 }
432 /* Some drivers (e.g. TUN) do not allocate HW header space */
433 if (skb_cow_head(skb, headroom: out_dev->hard_header_len))
434 goto out_dev;
435
436 if (dev_hard_header(skb, dev: out_dev, ETH_P_PHONET, NULL, NULL,
437 len: skb->len) < 0)
438 goto out_dev;
439 dev_queue_xmit(skb);
440 dev_put(dev: out_dev);
441 return NET_RX_SUCCESS;
442out_dev:
443 dev_put(dev: out_dev);
444 }
445
446out:
447 kfree_skb(skb);
448 return NET_RX_DROP;
449}
450
451static struct packet_type phonet_packet_type __read_mostly = {
452 .type = cpu_to_be16(ETH_P_PHONET),
453 .func = phonet_rcv,
454};
455
456static DEFINE_MUTEX(proto_tab_lock);
457
458int __init_or_module phonet_proto_register(unsigned int protocol,
459 const struct phonet_protocol *pp)
460{
461 int err = 0;
462
463 if (protocol >= PHONET_NPROTO)
464 return -EINVAL;
465
466 err = proto_register(prot: pp->prot, alloc_slab: 1);
467 if (err)
468 return err;
469
470 mutex_lock(&proto_tab_lock);
471 if (proto_tab[protocol])
472 err = -EBUSY;
473 else
474 rcu_assign_pointer(proto_tab[protocol], pp);
475 mutex_unlock(lock: &proto_tab_lock);
476
477 return err;
478}
479EXPORT_SYMBOL(phonet_proto_register);
480
481void phonet_proto_unregister(unsigned int protocol,
482 const struct phonet_protocol *pp)
483{
484 mutex_lock(&proto_tab_lock);
485 BUG_ON(proto_tab[protocol] != pp);
486 RCU_INIT_POINTER(proto_tab[protocol], NULL);
487 mutex_unlock(lock: &proto_tab_lock);
488 synchronize_rcu();
489 proto_unregister(prot: pp->prot);
490}
491EXPORT_SYMBOL(phonet_proto_unregister);
492
493/* Module registration */
494static int __init phonet_init(void)
495{
496 int err;
497
498 err = phonet_device_init();
499 if (err)
500 return err;
501
502 pn_sock_init();
503 err = sock_register(fam: &phonet_proto_family);
504 if (err) {
505 printk(KERN_ALERT
506 "phonet protocol family initialization failed\n");
507 goto err_sock;
508 }
509
510 dev_add_pack(pt: &phonet_packet_type);
511 phonet_sysctl_init();
512
513 err = isi_register();
514 if (err)
515 goto err;
516 return 0;
517
518err:
519 phonet_sysctl_exit();
520 sock_unregister(PF_PHONET);
521 dev_remove_pack(pt: &phonet_packet_type);
522err_sock:
523 phonet_device_exit();
524 return err;
525}
526
527static void __exit phonet_exit(void)
528{
529 isi_unregister();
530 phonet_sysctl_exit();
531 sock_unregister(PF_PHONET);
532 dev_remove_pack(pt: &phonet_packet_type);
533 phonet_device_exit();
534}
535
536module_init(phonet_init);
537module_exit(phonet_exit);
538MODULE_DESCRIPTION("Phonet protocol stack for Linux");
539MODULE_LICENSE("GPL");
540MODULE_ALIAS_NETPROTO(PF_PHONET);
541

source code of linux/net/phonet/af_phonet.c