Commit | Line | Data |
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02a47617 RDC |
1 | /* |
2 | * File: pep-gprs.c | |
3 | * | |
4 | * GPRS over Phonet pipe end point socket | |
5 | * | |
6 | * Copyright (C) 2008 Nokia Corporation. | |
7 | * | |
8 | * Author: Rémi Denis-Courmont <remi.denis-courmont@nokia.com> | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public License | |
12 | * version 2 as published by the Free Software Foundation. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, but | |
15 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA | |
22 | * 02110-1301 USA | |
23 | */ | |
24 | ||
25 | #include <linux/kernel.h> | |
26 | #include <linux/netdevice.h> | |
27 | #include <linux/if_ether.h> | |
28 | #include <linux/if_arp.h> | |
29 | #include <net/sock.h> | |
30 | ||
31 | #include <linux/if_phonet.h> | |
32 | #include <net/tcp_states.h> | |
33 | #include <net/phonet/gprs.h> | |
34 | ||
35 | #define GPRS_DEFAULT_MTU 1400 | |
36 | ||
37 | struct gprs_dev { | |
38 | struct sock *sk; | |
39 | void (*old_state_change)(struct sock *); | |
40 | void (*old_data_ready)(struct sock *, int); | |
41 | void (*old_write_space)(struct sock *); | |
42 | ||
43 | struct net_device *net; | |
44 | struct net_device_stats stats; | |
45 | ||
46 | struct sk_buff_head tx_queue; | |
47 | struct work_struct tx_work; | |
48 | spinlock_t tx_lock; | |
49 | unsigned tx_max; | |
50 | }; | |
51 | ||
52 | static int gprs_type_trans(struct sk_buff *skb) | |
53 | { | |
54 | const u8 *pvfc; | |
55 | u8 buf; | |
56 | ||
57 | pvfc = skb_header_pointer(skb, 0, 1, &buf); | |
58 | if (!pvfc) | |
59 | return 0; | |
60 | /* Look at IP version field */ | |
61 | switch (*pvfc >> 4) { | |
62 | case 4: | |
63 | return htons(ETH_P_IP); | |
64 | case 6: | |
65 | return htons(ETH_P_IPV6); | |
66 | } | |
67 | return 0; | |
68 | } | |
69 | ||
70 | /* | |
71 | * Socket callbacks | |
72 | */ | |
73 | ||
74 | static void gprs_state_change(struct sock *sk) | |
75 | { | |
76 | struct gprs_dev *dev = sk->sk_user_data; | |
77 | ||
78 | if (sk->sk_state == TCP_CLOSE_WAIT) { | |
79 | netif_stop_queue(dev->net); | |
80 | netif_carrier_off(dev->net); | |
81 | } | |
82 | } | |
83 | ||
84 | static int gprs_recv(struct gprs_dev *dev, struct sk_buff *skb) | |
85 | { | |
86 | int err = 0; | |
87 | u16 protocol = gprs_type_trans(skb); | |
88 | ||
89 | if (!protocol) { | |
90 | err = -EINVAL; | |
91 | goto drop; | |
92 | } | |
93 | ||
94 | if (likely(skb_headroom(skb) & 3)) { | |
95 | struct sk_buff *rskb, *fs; | |
96 | int flen = 0; | |
97 | ||
98 | /* Phonet Pipe data header is misaligned (3 bytes), | |
99 | * so wrap the IP packet as a single fragment of an head-less | |
100 | * socket buffer. The network stack will pull what it needs, | |
101 | * but at least, the whole IP payload is not memcpy'd. */ | |
102 | rskb = netdev_alloc_skb(dev->net, 0); | |
103 | if (!rskb) { | |
104 | err = -ENOBUFS; | |
105 | goto drop; | |
106 | } | |
107 | skb_shinfo(rskb)->frag_list = skb; | |
108 | rskb->len += skb->len; | |
109 | rskb->data_len += rskb->len; | |
110 | rskb->truesize += rskb->len; | |
111 | ||
112 | /* Avoid nested fragments */ | |
113 | for (fs = skb_shinfo(skb)->frag_list; fs; fs = fs->next) | |
114 | flen += fs->len; | |
115 | skb->next = skb_shinfo(skb)->frag_list; | |
116 | skb_shinfo(skb)->frag_list = NULL; | |
117 | skb->len -= flen; | |
118 | skb->data_len -= flen; | |
119 | skb->truesize -= flen; | |
120 | ||
121 | skb = rskb; | |
122 | } | |
123 | ||
124 | skb->protocol = protocol; | |
125 | skb_reset_mac_header(skb); | |
126 | skb->dev = dev->net; | |
127 | ||
128 | if (likely(dev->net->flags & IFF_UP)) { | |
129 | dev->stats.rx_packets++; | |
130 | dev->stats.rx_bytes += skb->len; | |
131 | netif_rx(skb); | |
132 | skb = NULL; | |
133 | } else | |
134 | err = -ENODEV; | |
135 | ||
136 | drop: | |
137 | if (skb) { | |
138 | dev_kfree_skb(skb); | |
139 | dev->stats.rx_dropped++; | |
140 | } | |
141 | return err; | |
142 | } | |
143 | ||
144 | static void gprs_data_ready(struct sock *sk, int len) | |
145 | { | |
146 | struct gprs_dev *dev = sk->sk_user_data; | |
147 | struct sk_buff *skb; | |
148 | ||
149 | while ((skb = pep_read(sk)) != NULL) { | |
150 | skb_orphan(skb); | |
151 | gprs_recv(dev, skb); | |
152 | } | |
153 | } | |
154 | ||
155 | static void gprs_write_space(struct sock *sk) | |
156 | { | |
157 | struct gprs_dev *dev = sk->sk_user_data; | |
158 | unsigned credits = pep_writeable(sk); | |
159 | ||
160 | spin_lock_bh(&dev->tx_lock); | |
161 | dev->tx_max = credits; | |
162 | if (credits > skb_queue_len(&dev->tx_queue)) | |
163 | netif_wake_queue(dev->net); | |
164 | spin_unlock_bh(&dev->tx_lock); | |
165 | } | |
166 | ||
167 | /* | |
168 | * Network device callbacks | |
169 | */ | |
170 | ||
171 | static int gprs_xmit(struct sk_buff *skb, struct net_device *net) | |
172 | { | |
173 | struct gprs_dev *dev = netdev_priv(net); | |
174 | ||
175 | switch (skb->protocol) { | |
176 | case htons(ETH_P_IP): | |
177 | case htons(ETH_P_IPV6): | |
178 | break; | |
179 | default: | |
180 | dev_kfree_skb(skb); | |
181 | return 0; | |
182 | } | |
183 | ||
184 | spin_lock(&dev->tx_lock); | |
185 | if (likely(skb_queue_len(&dev->tx_queue) < dev->tx_max)) { | |
186 | skb_queue_tail(&dev->tx_queue, skb); | |
187 | skb = NULL; | |
188 | } | |
189 | if (skb_queue_len(&dev->tx_queue) >= dev->tx_max) | |
190 | netif_stop_queue(net); | |
191 | spin_unlock(&dev->tx_lock); | |
192 | ||
193 | schedule_work(&dev->tx_work); | |
194 | if (unlikely(skb)) | |
195 | dev_kfree_skb(skb); | |
196 | return 0; | |
197 | } | |
198 | ||
199 | static void gprs_tx(struct work_struct *work) | |
200 | { | |
201 | struct gprs_dev *dev = container_of(work, struct gprs_dev, tx_work); | |
202 | struct sock *sk = dev->sk; | |
203 | struct sk_buff *skb; | |
204 | ||
205 | while ((skb = skb_dequeue(&dev->tx_queue)) != NULL) { | |
206 | int err; | |
207 | ||
208 | dev->stats.tx_bytes += skb->len; | |
209 | dev->stats.tx_packets++; | |
210 | ||
211 | skb_orphan(skb); | |
212 | skb_set_owner_w(skb, sk); | |
213 | ||
214 | lock_sock(sk); | |
215 | err = pep_write(sk, skb); | |
216 | if (err) { | |
217 | LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n", | |
218 | dev->net->name, err); | |
219 | dev->stats.tx_aborted_errors++; | |
220 | dev->stats.tx_errors++; | |
221 | } | |
222 | release_sock(sk); | |
223 | } | |
224 | ||
225 | lock_sock(sk); | |
226 | gprs_write_space(sk); | |
227 | release_sock(sk); | |
228 | } | |
229 | ||
230 | static int gprs_set_mtu(struct net_device *net, int new_mtu) | |
231 | { | |
232 | if ((new_mtu < 576) || (new_mtu > (PHONET_MAX_MTU - 11))) | |
233 | return -EINVAL; | |
234 | ||
235 | net->mtu = new_mtu; | |
236 | return 0; | |
237 | } | |
238 | ||
239 | static struct net_device_stats *gprs_get_stats(struct net_device *net) | |
240 | { | |
241 | struct gprs_dev *dev = netdev_priv(net); | |
242 | ||
243 | return &dev->stats; | |
244 | } | |
245 | ||
246 | static void gprs_setup(struct net_device *net) | |
247 | { | |
248 | net->features = NETIF_F_FRAGLIST; | |
249 | net->type = ARPHRD_NONE; | |
250 | net->flags = IFF_POINTOPOINT | IFF_NOARP; | |
251 | net->mtu = GPRS_DEFAULT_MTU; | |
252 | net->hard_header_len = 0; | |
253 | net->addr_len = 0; | |
254 | net->tx_queue_len = 10; | |
255 | ||
256 | net->destructor = free_netdev; | |
257 | net->hard_start_xmit = gprs_xmit; /* mandatory */ | |
258 | net->change_mtu = gprs_set_mtu; | |
259 | net->get_stats = gprs_get_stats; | |
260 | } | |
261 | ||
262 | /* | |
263 | * External interface | |
264 | */ | |
265 | ||
266 | /* | |
267 | * Attach a GPRS interface to a datagram socket. | |
268 | * Returns the interface index on success, negative error code on error. | |
269 | */ | |
270 | int gprs_attach(struct sock *sk) | |
271 | { | |
272 | static const char ifname[] = "gprs%d"; | |
273 | struct gprs_dev *dev; | |
274 | struct net_device *net; | |
275 | int err; | |
276 | ||
277 | if (unlikely(sk->sk_type == SOCK_STREAM)) | |
278 | return -EINVAL; /* need packet boundaries */ | |
279 | ||
280 | /* Create net device */ | |
281 | net = alloc_netdev(sizeof(*dev), ifname, gprs_setup); | |
282 | if (!net) | |
283 | return -ENOMEM; | |
284 | dev = netdev_priv(net); | |
285 | dev->net = net; | |
286 | dev->tx_max = 0; | |
287 | spin_lock_init(&dev->tx_lock); | |
288 | skb_queue_head_init(&dev->tx_queue); | |
289 | INIT_WORK(&dev->tx_work, gprs_tx); | |
290 | ||
291 | netif_stop_queue(net); | |
292 | err = register_netdev(net); | |
293 | if (err) { | |
294 | free_netdev(net); | |
295 | return err; | |
296 | } | |
297 | ||
298 | lock_sock(sk); | |
299 | if (unlikely(sk->sk_user_data)) { | |
300 | err = -EBUSY; | |
301 | goto out_rel; | |
302 | } | |
303 | if (unlikely((1 << sk->sk_state & (TCPF_CLOSE|TCPF_LISTEN)) || | |
304 | sock_flag(sk, SOCK_DEAD))) { | |
305 | err = -EINVAL; | |
306 | goto out_rel; | |
307 | } | |
308 | sk->sk_user_data = dev; | |
309 | dev->old_state_change = sk->sk_state_change; | |
310 | dev->old_data_ready = sk->sk_data_ready; | |
311 | dev->old_write_space = sk->sk_write_space; | |
312 | sk->sk_state_change = gprs_state_change; | |
313 | sk->sk_data_ready = gprs_data_ready; | |
314 | sk->sk_write_space = gprs_write_space; | |
315 | release_sock(sk); | |
316 | ||
317 | sock_hold(sk); | |
318 | dev->sk = sk; | |
319 | ||
320 | printk(KERN_DEBUG"%s: attached\n", net->name); | |
321 | gprs_write_space(sk); /* kick off TX */ | |
322 | return net->ifindex; | |
323 | ||
324 | out_rel: | |
325 | release_sock(sk); | |
326 | unregister_netdev(net); | |
327 | return err; | |
328 | } | |
329 | ||
330 | void gprs_detach(struct sock *sk) | |
331 | { | |
332 | struct gprs_dev *dev = sk->sk_user_data; | |
333 | struct net_device *net = dev->net; | |
334 | ||
335 | lock_sock(sk); | |
336 | sk->sk_user_data = NULL; | |
337 | sk->sk_state_change = dev->old_state_change; | |
338 | sk->sk_data_ready = dev->old_data_ready; | |
339 | sk->sk_write_space = dev->old_write_space; | |
340 | release_sock(sk); | |
341 | ||
342 | printk(KERN_DEBUG"%s: detached\n", net->name); | |
343 | unregister_netdev(net); | |
344 | flush_scheduled_work(); | |
345 | sock_put(sk); | |
346 | skb_queue_purge(&dev->tx_queue); | |
347 | } |