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rawsock.c
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1 /*
2  * Copyright (C) 2011 Instituto Nokia de Tecnologia
3  *
4  * Authors:
5  * Aloisio Almeida Jr <[email protected]>
6  * Lauro Ramos Venancio <[email protected]>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the
20  * Free Software Foundation, Inc.,
21  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22  */
23 
24 #define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
25 
26 #include <net/tcp_states.h>
27 #include <linux/nfc.h>
28 #include <linux/export.h>
29 
30 #include "nfc.h"
31 
32 static void rawsock_write_queue_purge(struct sock *sk)
33 {
34  pr_debug("sk=%p\n", sk);
35 
36  spin_lock_bh(&sk->sk_write_queue.lock);
37  __skb_queue_purge(&sk->sk_write_queue);
38  nfc_rawsock(sk)->tx_work_scheduled = false;
39  spin_unlock_bh(&sk->sk_write_queue.lock);
40 }
41 
42 static void rawsock_report_error(struct sock *sk, int err)
43 {
44  pr_debug("sk=%p err=%d\n", sk, err);
45 
47  sk->sk_err = -err;
48  sk->sk_error_report(sk);
49 
50  rawsock_write_queue_purge(sk);
51 }
52 
53 static int rawsock_release(struct socket *sock)
54 {
55  struct sock *sk = sock->sk;
56 
57  pr_debug("sock=%p sk=%p\n", sock, sk);
58 
59  if (!sk)
60  return 0;
61 
62  sock_orphan(sk);
63  sock_put(sk);
64 
65  return 0;
66 }
67 
68 static int rawsock_connect(struct socket *sock, struct sockaddr *_addr,
69  int len, int flags)
70 {
71  struct sock *sk = sock->sk;
72  struct sockaddr_nfc *addr = (struct sockaddr_nfc *)_addr;
73  struct nfc_dev *dev;
74  int rc = 0;
75 
76  pr_debug("sock=%p sk=%p flags=%d\n", sock, sk, flags);
77 
78  if (!addr || len < sizeof(struct sockaddr_nfc) ||
79  addr->sa_family != AF_NFC)
80  return -EINVAL;
81 
82  pr_debug("addr dev_idx=%u target_idx=%u protocol=%u\n",
83  addr->dev_idx, addr->target_idx, addr->nfc_protocol);
84 
85  lock_sock(sk);
86 
87  if (sock->state == SS_CONNECTED) {
88  rc = -EISCONN;
89  goto error;
90  }
91 
92  dev = nfc_get_device(addr->dev_idx);
93  if (!dev) {
94  rc = -ENODEV;
95  goto error;
96  }
97 
98  if (addr->target_idx > dev->target_next_idx - 1 ||
99  addr->target_idx < dev->target_next_idx - dev->n_targets) {
100  rc = -EINVAL;
101  goto error;
102  }
103 
104  rc = nfc_activate_target(dev, addr->target_idx, addr->nfc_protocol);
105  if (rc)
106  goto put_dev;
107 
108  nfc_rawsock(sk)->dev = dev;
109  nfc_rawsock(sk)->target_idx = addr->target_idx;
110  sock->state = SS_CONNECTED;
111  sk->sk_state = TCP_ESTABLISHED;
112  sk->sk_state_change(sk);
113 
114  release_sock(sk);
115  return 0;
116 
117 put_dev:
118  nfc_put_device(dev);
119 error:
120  release_sock(sk);
121  return rc;
122 }
123 
124 static int rawsock_add_header(struct sk_buff *skb)
125 {
126  *skb_push(skb, NFC_HEADER_SIZE) = 0;
127 
128  return 0;
129 }
130 
131 static void rawsock_data_exchange_complete(void *context, struct sk_buff *skb,
132  int err)
133 {
134  struct sock *sk = (struct sock *) context;
135 
136  BUG_ON(in_irq());
137 
138  pr_debug("sk=%p err=%d\n", sk, err);
139 
140  if (err)
141  goto error;
142 
143  err = rawsock_add_header(skb);
144  if (err)
145  goto error;
146 
147  err = sock_queue_rcv_skb(sk, skb);
148  if (err)
149  goto error;
150 
151  spin_lock_bh(&sk->sk_write_queue.lock);
152  if (!skb_queue_empty(&sk->sk_write_queue))
153  schedule_work(&nfc_rawsock(sk)->tx_work);
154  else
155  nfc_rawsock(sk)->tx_work_scheduled = false;
156  spin_unlock_bh(&sk->sk_write_queue.lock);
157 
158  sock_put(sk);
159  return;
160 
161 error:
162  rawsock_report_error(sk, err);
163  sock_put(sk);
164 }
165 
166 static void rawsock_tx_work(struct work_struct *work)
167 {
168  struct sock *sk = to_rawsock_sk(work);
169  struct nfc_dev *dev = nfc_rawsock(sk)->dev;
170  u32 target_idx = nfc_rawsock(sk)->target_idx;
171  struct sk_buff *skb;
172  int rc;
173 
174  pr_debug("sk=%p target_idx=%u\n", sk, target_idx);
175 
176  if (sk->sk_shutdown & SEND_SHUTDOWN) {
177  rawsock_write_queue_purge(sk);
178  return;
179  }
180 
181  skb = skb_dequeue(&sk->sk_write_queue);
182 
183  sock_hold(sk);
184  rc = nfc_data_exchange(dev, target_idx, skb,
185  rawsock_data_exchange_complete, sk);
186  if (rc) {
187  rawsock_report_error(sk, rc);
188  sock_put(sk);
189  }
190 }
191 
192 static int rawsock_sendmsg(struct kiocb *iocb, struct socket *sock,
193  struct msghdr *msg, size_t len)
194 {
195  struct sock *sk = sock->sk;
196  struct nfc_dev *dev = nfc_rawsock(sk)->dev;
197  struct sk_buff *skb;
198  int rc;
199 
200  pr_debug("sock=%p sk=%p len=%zu\n", sock, sk, len);
201 
202  if (msg->msg_namelen)
203  return -EOPNOTSUPP;
204 
205  if (sock->state != SS_CONNECTED)
206  return -ENOTCONN;
207 
208  skb = nfc_alloc_send_skb(dev, sk, msg->msg_flags, len, &rc);
209  if (skb == NULL)
210  return rc;
211 
212  rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
213  if (rc < 0) {
214  kfree_skb(skb);
215  return rc;
216  }
217 
218  spin_lock_bh(&sk->sk_write_queue.lock);
219  __skb_queue_tail(&sk->sk_write_queue, skb);
220  if (!nfc_rawsock(sk)->tx_work_scheduled) {
221  schedule_work(&nfc_rawsock(sk)->tx_work);
222  nfc_rawsock(sk)->tx_work_scheduled = true;
223  }
224  spin_unlock_bh(&sk->sk_write_queue.lock);
225 
226  return len;
227 }
228 
229 static int rawsock_recvmsg(struct kiocb *iocb, struct socket *sock,
230  struct msghdr *msg, size_t len, int flags)
231 {
232  int noblock = flags & MSG_DONTWAIT;
233  struct sock *sk = sock->sk;
234  struct sk_buff *skb;
235  int copied;
236  int rc;
237 
238  pr_debug("sock=%p sk=%p len=%zu flags=%d\n", sock, sk, len, flags);
239 
240  skb = skb_recv_datagram(sk, flags, noblock, &rc);
241  if (!skb)
242  return rc;
243 
244  msg->msg_namelen = 0;
245 
246  copied = skb->len;
247  if (len < copied) {
248  msg->msg_flags |= MSG_TRUNC;
249  copied = len;
250  }
251 
252  rc = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
253 
254  skb_free_datagram(sk, skb);
255 
256  return rc ? : copied;
257 }
258 
259 
260 static const struct proto_ops rawsock_ops = {
261  .family = PF_NFC,
262  .owner = THIS_MODULE,
263  .release = rawsock_release,
264  .bind = sock_no_bind,
265  .connect = rawsock_connect,
266  .socketpair = sock_no_socketpair,
267  .accept = sock_no_accept,
268  .getname = sock_no_getname,
269  .poll = datagram_poll,
270  .ioctl = sock_no_ioctl,
271  .listen = sock_no_listen,
272  .shutdown = sock_no_shutdown,
273  .setsockopt = sock_no_setsockopt,
274  .getsockopt = sock_no_getsockopt,
275  .sendmsg = rawsock_sendmsg,
276  .recvmsg = rawsock_recvmsg,
277  .mmap = sock_no_mmap,
278 };
279 
280 static void rawsock_destruct(struct sock *sk)
281 {
282  pr_debug("sk=%p\n", sk);
283 
284  if (sk->sk_state == TCP_ESTABLISHED) {
286  nfc_rawsock(sk)->target_idx);
287  nfc_put_device(nfc_rawsock(sk)->dev);
288  }
289 
291 
292  if (!sock_flag(sk, SOCK_DEAD)) {
293  pr_err("Freeing alive NFC raw socket %p\n", sk);
294  return;
295  }
296 }
297 
298 static int rawsock_create(struct net *net, struct socket *sock,
299  const struct nfc_protocol *nfc_proto)
300 {
301  struct sock *sk;
302 
303  pr_debug("sock=%p\n", sock);
304 
305  if (sock->type != SOCK_SEQPACKET)
306  return -ESOCKTNOSUPPORT;
307 
308  sock->ops = &rawsock_ops;
309 
310  sk = sk_alloc(net, PF_NFC, GFP_ATOMIC, nfc_proto->proto);
311  if (!sk)
312  return -ENOMEM;
313 
314  sock_init_data(sock, sk);
315  sk->sk_protocol = nfc_proto->id;
316  sk->sk_destruct = rawsock_destruct;
317  sock->state = SS_UNCONNECTED;
318 
319  INIT_WORK(&nfc_rawsock(sk)->tx_work, rawsock_tx_work);
320  nfc_rawsock(sk)->tx_work_scheduled = false;
321 
322  return 0;
323 }
324 
325 static struct proto rawsock_proto = {
326  .name = "NFC_RAW",
327  .owner = THIS_MODULE,
328  .obj_size = sizeof(struct nfc_rawsock),
329 };
330 
331 static const struct nfc_protocol rawsock_nfc_proto = {
332  .id = NFC_SOCKPROTO_RAW,
333  .proto = &rawsock_proto,
334  .owner = THIS_MODULE,
335  .create = rawsock_create
336 };
337 
339 {
340  int rc;
341 
342  rc = nfc_proto_register(&rawsock_nfc_proto);
343 
344  return rc;
345 }
346 
347 void rawsock_exit(void)
348 {
349  nfc_proto_unregister(&rawsock_nfc_proto);
350 }