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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; | |
02a47617 RDC |
44 | |
45 | struct sk_buff_head tx_queue; | |
46 | struct work_struct tx_work; | |
47 | spinlock_t tx_lock; | |
48 | unsigned tx_max; | |
49 | }; | |
50 | ||
5c7f0333 | 51 | static __be16 gprs_type_trans(struct sk_buff *skb) |
02a47617 RDC |
52 | { |
53 | const u8 *pvfc; | |
54 | u8 buf; | |
55 | ||
56 | pvfc = skb_header_pointer(skb, 0, 1, &buf); | |
57 | if (!pvfc) | |
5c7f0333 | 58 | return htons(0); |
02a47617 RDC |
59 | /* Look at IP version field */ |
60 | switch (*pvfc >> 4) { | |
61 | case 4: | |
62 | return htons(ETH_P_IP); | |
63 | case 6: | |
64 | return htons(ETH_P_IPV6); | |
65 | } | |
5c7f0333 | 66 | return htons(0); |
02a47617 RDC |
67 | } |
68 | ||
69 | /* | |
70 | * Socket callbacks | |
71 | */ | |
72 | ||
73 | static void gprs_state_change(struct sock *sk) | |
74 | { | |
75 | struct gprs_dev *dev = sk->sk_user_data; | |
76 | ||
77 | if (sk->sk_state == TCP_CLOSE_WAIT) { | |
78 | netif_stop_queue(dev->net); | |
79 | netif_carrier_off(dev->net); | |
80 | } | |
81 | } | |
82 | ||
83 | static int gprs_recv(struct gprs_dev *dev, struct sk_buff *skb) | |
84 | { | |
9b1582d4 | 85 | struct net_device *net = dev->net; |
02a47617 | 86 | int err = 0; |
5c7f0333 | 87 | __be16 protocol = gprs_type_trans(skb); |
02a47617 RDC |
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. */ | |
9b1582d4 | 102 | rskb = netdev_alloc_skb(net, 0); |
02a47617 RDC |
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); | |
9b1582d4 | 126 | skb->dev = net; |
02a47617 | 127 | |
9b1582d4 RDC |
128 | if (likely(net->flags & IFF_UP)) { |
129 | net->stats.rx_packets++; | |
130 | net->stats.rx_bytes += skb->len; | |
02a47617 RDC |
131 | netif_rx(skb); |
132 | skb = NULL; | |
133 | } else | |
134 | err = -ENODEV; | |
135 | ||
136 | drop: | |
137 | if (skb) { | |
138 | dev_kfree_skb(skb); | |
9b1582d4 | 139 | net->stats.rx_dropped++; |
02a47617 RDC |
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; | |
4798a2b8 | 158 | struct net_device *net = dev->net; |
02a47617 RDC |
159 | unsigned credits = pep_writeable(sk); |
160 | ||
161 | spin_lock_bh(&dev->tx_lock); | |
162 | dev->tx_max = credits; | |
4798a2b8 RDC |
163 | if (credits > skb_queue_len(&dev->tx_queue) && netif_running(net)) |
164 | netif_wake_queue(net); | |
02a47617 RDC |
165 | spin_unlock_bh(&dev->tx_lock); |
166 | } | |
167 | ||
168 | /* | |
169 | * Network device callbacks | |
170 | */ | |
171 | ||
4798a2b8 RDC |
172 | static int gprs_open(struct net_device *dev) |
173 | { | |
174 | struct gprs_dev *gp = netdev_priv(dev); | |
175 | ||
176 | gprs_write_space(gp->sk); | |
177 | return 0; | |
178 | } | |
179 | ||
180 | static int gprs_close(struct net_device *dev) | |
181 | { | |
182 | struct gprs_dev *gp = netdev_priv(dev); | |
183 | ||
184 | netif_stop_queue(dev); | |
185 | flush_work(&gp->tx_work); | |
186 | return 0; | |
187 | } | |
188 | ||
02a47617 RDC |
189 | static int gprs_xmit(struct sk_buff *skb, struct net_device *net) |
190 | { | |
191 | struct gprs_dev *dev = netdev_priv(net); | |
192 | ||
193 | switch (skb->protocol) { | |
194 | case htons(ETH_P_IP): | |
195 | case htons(ETH_P_IPV6): | |
196 | break; | |
197 | default: | |
198 | dev_kfree_skb(skb); | |
199 | return 0; | |
200 | } | |
201 | ||
202 | spin_lock(&dev->tx_lock); | |
203 | if (likely(skb_queue_len(&dev->tx_queue) < dev->tx_max)) { | |
204 | skb_queue_tail(&dev->tx_queue, skb); | |
205 | skb = NULL; | |
206 | } | |
207 | if (skb_queue_len(&dev->tx_queue) >= dev->tx_max) | |
208 | netif_stop_queue(net); | |
209 | spin_unlock(&dev->tx_lock); | |
210 | ||
211 | schedule_work(&dev->tx_work); | |
212 | if (unlikely(skb)) | |
213 | dev_kfree_skb(skb); | |
214 | return 0; | |
215 | } | |
216 | ||
217 | static void gprs_tx(struct work_struct *work) | |
218 | { | |
219 | struct gprs_dev *dev = container_of(work, struct gprs_dev, tx_work); | |
9b1582d4 | 220 | struct net_device *net = dev->net; |
02a47617 RDC |
221 | struct sock *sk = dev->sk; |
222 | struct sk_buff *skb; | |
223 | ||
224 | while ((skb = skb_dequeue(&dev->tx_queue)) != NULL) { | |
225 | int err; | |
226 | ||
9b1582d4 RDC |
227 | net->stats.tx_bytes += skb->len; |
228 | net->stats.tx_packets++; | |
02a47617 RDC |
229 | |
230 | skb_orphan(skb); | |
231 | skb_set_owner_w(skb, sk); | |
232 | ||
233 | lock_sock(sk); | |
234 | err = pep_write(sk, skb); | |
235 | if (err) { | |
236 | LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n", | |
9b1582d4 RDC |
237 | net->name, err); |
238 | net->stats.tx_aborted_errors++; | |
239 | net->stats.tx_errors++; | |
02a47617 RDC |
240 | } |
241 | release_sock(sk); | |
242 | } | |
243 | ||
244 | lock_sock(sk); | |
245 | gprs_write_space(sk); | |
246 | release_sock(sk); | |
247 | } | |
248 | ||
249 | static int gprs_set_mtu(struct net_device *net, int new_mtu) | |
250 | { | |
251 | if ((new_mtu < 576) || (new_mtu > (PHONET_MAX_MTU - 11))) | |
252 | return -EINVAL; | |
253 | ||
254 | net->mtu = new_mtu; | |
255 | return 0; | |
256 | } | |
257 | ||
02a47617 RDC |
258 | static void gprs_setup(struct net_device *net) |
259 | { | |
260 | net->features = NETIF_F_FRAGLIST; | |
261 | net->type = ARPHRD_NONE; | |
262 | net->flags = IFF_POINTOPOINT | IFF_NOARP; | |
263 | net->mtu = GPRS_DEFAULT_MTU; | |
264 | net->hard_header_len = 0; | |
265 | net->addr_len = 0; | |
266 | net->tx_queue_len = 10; | |
267 | ||
268 | net->destructor = free_netdev; | |
4798a2b8 RDC |
269 | net->open = gprs_open; |
270 | net->stop = gprs_close; | |
02a47617 RDC |
271 | net->hard_start_xmit = gprs_xmit; /* mandatory */ |
272 | net->change_mtu = gprs_set_mtu; | |
02a47617 RDC |
273 | } |
274 | ||
275 | /* | |
276 | * External interface | |
277 | */ | |
278 | ||
279 | /* | |
280 | * Attach a GPRS interface to a datagram socket. | |
281 | * Returns the interface index on success, negative error code on error. | |
282 | */ | |
283 | int gprs_attach(struct sock *sk) | |
284 | { | |
285 | static const char ifname[] = "gprs%d"; | |
286 | struct gprs_dev *dev; | |
287 | struct net_device *net; | |
288 | int err; | |
289 | ||
290 | if (unlikely(sk->sk_type == SOCK_STREAM)) | |
291 | return -EINVAL; /* need packet boundaries */ | |
292 | ||
293 | /* Create net device */ | |
294 | net = alloc_netdev(sizeof(*dev), ifname, gprs_setup); | |
295 | if (!net) | |
296 | return -ENOMEM; | |
297 | dev = netdev_priv(net); | |
298 | dev->net = net; | |
299 | dev->tx_max = 0; | |
300 | spin_lock_init(&dev->tx_lock); | |
301 | skb_queue_head_init(&dev->tx_queue); | |
302 | INIT_WORK(&dev->tx_work, gprs_tx); | |
303 | ||
304 | netif_stop_queue(net); | |
305 | err = register_netdev(net); | |
306 | if (err) { | |
307 | free_netdev(net); | |
308 | return err; | |
309 | } | |
310 | ||
311 | lock_sock(sk); | |
312 | if (unlikely(sk->sk_user_data)) { | |
313 | err = -EBUSY; | |
314 | goto out_rel; | |
315 | } | |
316 | if (unlikely((1 << sk->sk_state & (TCPF_CLOSE|TCPF_LISTEN)) || | |
317 | sock_flag(sk, SOCK_DEAD))) { | |
318 | err = -EINVAL; | |
319 | goto out_rel; | |
320 | } | |
321 | sk->sk_user_data = dev; | |
322 | dev->old_state_change = sk->sk_state_change; | |
323 | dev->old_data_ready = sk->sk_data_ready; | |
324 | dev->old_write_space = sk->sk_write_space; | |
325 | sk->sk_state_change = gprs_state_change; | |
326 | sk->sk_data_ready = gprs_data_ready; | |
327 | sk->sk_write_space = gprs_write_space; | |
328 | release_sock(sk); | |
329 | ||
330 | sock_hold(sk); | |
331 | dev->sk = sk; | |
332 | ||
333 | printk(KERN_DEBUG"%s: attached\n", net->name); | |
02a47617 RDC |
334 | return net->ifindex; |
335 | ||
336 | out_rel: | |
337 | release_sock(sk); | |
338 | unregister_netdev(net); | |
339 | return err; | |
340 | } | |
341 | ||
342 | void gprs_detach(struct sock *sk) | |
343 | { | |
344 | struct gprs_dev *dev = sk->sk_user_data; | |
345 | struct net_device *net = dev->net; | |
346 | ||
347 | lock_sock(sk); | |
348 | sk->sk_user_data = NULL; | |
349 | sk->sk_state_change = dev->old_state_change; | |
350 | sk->sk_data_ready = dev->old_data_ready; | |
351 | sk->sk_write_space = dev->old_write_space; | |
352 | release_sock(sk); | |
353 | ||
354 | printk(KERN_DEBUG"%s: detached\n", net->name); | |
355 | unregister_netdev(net); | |
02a47617 | 356 | sock_put(sk); |
02a47617 | 357 | } |