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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 | ||
09a2c3c0 | 43 | struct net_device *dev; |
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 | { | |
09a2c3c0 | 75 | struct gprs_dev *gp = sk->sk_user_data; |
02a47617 RDC |
76 | |
77 | if (sk->sk_state == TCP_CLOSE_WAIT) { | |
09a2c3c0 RDC |
78 | struct net_device *dev = gp->dev; |
79 | ||
80 | netif_stop_queue(dev); | |
81 | netif_carrier_off(dev); | |
02a47617 RDC |
82 | } |
83 | } | |
84 | ||
09a2c3c0 | 85 | static int gprs_recv(struct gprs_dev *gp, struct sk_buff *skb) |
02a47617 | 86 | { |
09a2c3c0 | 87 | struct net_device *dev = gp->dev; |
02a47617 | 88 | int err = 0; |
5c7f0333 | 89 | __be16 protocol = gprs_type_trans(skb); |
02a47617 RDC |
90 | |
91 | if (!protocol) { | |
92 | err = -EINVAL; | |
93 | goto drop; | |
94 | } | |
95 | ||
96 | if (likely(skb_headroom(skb) & 3)) { | |
97 | struct sk_buff *rskb, *fs; | |
98 | int flen = 0; | |
99 | ||
100 | /* Phonet Pipe data header is misaligned (3 bytes), | |
101 | * so wrap the IP packet as a single fragment of an head-less | |
102 | * socket buffer. The network stack will pull what it needs, | |
103 | * but at least, the whole IP payload is not memcpy'd. */ | |
09a2c3c0 | 104 | rskb = netdev_alloc_skb(dev, 0); |
02a47617 RDC |
105 | if (!rskb) { |
106 | err = -ENOBUFS; | |
107 | goto drop; | |
108 | } | |
109 | skb_shinfo(rskb)->frag_list = skb; | |
110 | rskb->len += skb->len; | |
111 | rskb->data_len += rskb->len; | |
112 | rskb->truesize += rskb->len; | |
113 | ||
114 | /* Avoid nested fragments */ | |
115 | for (fs = skb_shinfo(skb)->frag_list; fs; fs = fs->next) | |
116 | flen += fs->len; | |
117 | skb->next = skb_shinfo(skb)->frag_list; | |
118 | skb_shinfo(skb)->frag_list = NULL; | |
119 | skb->len -= flen; | |
120 | skb->data_len -= flen; | |
121 | skb->truesize -= flen; | |
122 | ||
123 | skb = rskb; | |
124 | } | |
125 | ||
126 | skb->protocol = protocol; | |
127 | skb_reset_mac_header(skb); | |
09a2c3c0 | 128 | skb->dev = dev; |
02a47617 | 129 | |
09a2c3c0 RDC |
130 | if (likely(dev->flags & IFF_UP)) { |
131 | dev->stats.rx_packets++; | |
132 | dev->stats.rx_bytes += skb->len; | |
02a47617 RDC |
133 | netif_rx(skb); |
134 | skb = NULL; | |
135 | } else | |
136 | err = -ENODEV; | |
137 | ||
138 | drop: | |
139 | if (skb) { | |
140 | dev_kfree_skb(skb); | |
09a2c3c0 | 141 | dev->stats.rx_dropped++; |
02a47617 RDC |
142 | } |
143 | return err; | |
144 | } | |
145 | ||
146 | static void gprs_data_ready(struct sock *sk, int len) | |
147 | { | |
09a2c3c0 | 148 | struct gprs_dev *gp = sk->sk_user_data; |
02a47617 RDC |
149 | struct sk_buff *skb; |
150 | ||
151 | while ((skb = pep_read(sk)) != NULL) { | |
152 | skb_orphan(skb); | |
09a2c3c0 | 153 | gprs_recv(gp, skb); |
02a47617 RDC |
154 | } |
155 | } | |
156 | ||
157 | static void gprs_write_space(struct sock *sk) | |
158 | { | |
09a2c3c0 RDC |
159 | struct gprs_dev *gp = sk->sk_user_data; |
160 | struct net_device *dev = gp->dev; | |
02a47617 RDC |
161 | unsigned credits = pep_writeable(sk); |
162 | ||
09a2c3c0 RDC |
163 | spin_lock_bh(&gp->tx_lock); |
164 | gp->tx_max = credits; | |
165 | if (credits > skb_queue_len(&gp->tx_queue) && netif_running(dev)) | |
166 | netif_wake_queue(dev); | |
167 | spin_unlock_bh(&gp->tx_lock); | |
02a47617 RDC |
168 | } |
169 | ||
170 | /* | |
171 | * Network device callbacks | |
172 | */ | |
173 | ||
4798a2b8 RDC |
174 | static int gprs_open(struct net_device *dev) |
175 | { | |
176 | struct gprs_dev *gp = netdev_priv(dev); | |
177 | ||
178 | gprs_write_space(gp->sk); | |
179 | return 0; | |
180 | } | |
181 | ||
182 | static int gprs_close(struct net_device *dev) | |
183 | { | |
184 | struct gprs_dev *gp = netdev_priv(dev); | |
185 | ||
186 | netif_stop_queue(dev); | |
187 | flush_work(&gp->tx_work); | |
188 | return 0; | |
189 | } | |
190 | ||
09a2c3c0 | 191 | static int gprs_xmit(struct sk_buff *skb, struct net_device *dev) |
02a47617 | 192 | { |
09a2c3c0 | 193 | struct gprs_dev *gp = netdev_priv(dev); |
02a47617 RDC |
194 | |
195 | switch (skb->protocol) { | |
196 | case htons(ETH_P_IP): | |
197 | case htons(ETH_P_IPV6): | |
198 | break; | |
199 | default: | |
200 | dev_kfree_skb(skb); | |
201 | return 0; | |
202 | } | |
203 | ||
09a2c3c0 RDC |
204 | spin_lock(&gp->tx_lock); |
205 | if (likely(skb_queue_len(&gp->tx_queue) < gp->tx_max)) { | |
206 | skb_queue_tail(&gp->tx_queue, skb); | |
02a47617 RDC |
207 | skb = NULL; |
208 | } | |
09a2c3c0 RDC |
209 | if (skb_queue_len(&gp->tx_queue) >= gp->tx_max) |
210 | netif_stop_queue(dev); | |
211 | spin_unlock(&gp->tx_lock); | |
02a47617 | 212 | |
09a2c3c0 | 213 | schedule_work(&gp->tx_work); |
02a47617 RDC |
214 | if (unlikely(skb)) |
215 | dev_kfree_skb(skb); | |
216 | return 0; | |
217 | } | |
218 | ||
219 | static void gprs_tx(struct work_struct *work) | |
220 | { | |
09a2c3c0 RDC |
221 | struct gprs_dev *gp = container_of(work, struct gprs_dev, tx_work); |
222 | struct net_device *dev = gp->dev; | |
223 | struct sock *sk = gp->sk; | |
02a47617 RDC |
224 | struct sk_buff *skb; |
225 | ||
09a2c3c0 | 226 | while ((skb = skb_dequeue(&gp->tx_queue)) != NULL) { |
02a47617 RDC |
227 | int err; |
228 | ||
09a2c3c0 RDC |
229 | dev->stats.tx_bytes += skb->len; |
230 | dev->stats.tx_packets++; | |
02a47617 RDC |
231 | |
232 | skb_orphan(skb); | |
233 | skb_set_owner_w(skb, sk); | |
234 | ||
235 | lock_sock(sk); | |
236 | err = pep_write(sk, skb); | |
237 | if (err) { | |
238 | LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n", | |
09a2c3c0 RDC |
239 | dev->name, err); |
240 | dev->stats.tx_aborted_errors++; | |
241 | dev->stats.tx_errors++; | |
02a47617 RDC |
242 | } |
243 | release_sock(sk); | |
244 | } | |
245 | ||
246 | lock_sock(sk); | |
247 | gprs_write_space(sk); | |
248 | release_sock(sk); | |
249 | } | |
250 | ||
09a2c3c0 | 251 | static int gprs_set_mtu(struct net_device *dev, int new_mtu) |
02a47617 RDC |
252 | { |
253 | if ((new_mtu < 576) || (new_mtu > (PHONET_MAX_MTU - 11))) | |
254 | return -EINVAL; | |
255 | ||
09a2c3c0 | 256 | dev->mtu = new_mtu; |
02a47617 RDC |
257 | return 0; |
258 | } | |
259 | ||
09a2c3c0 | 260 | static void gprs_setup(struct net_device *dev) |
02a47617 | 261 | { |
09a2c3c0 | 262 | dev->features = NETIF_F_FRAGLIST; |
57c81fff | 263 | dev->type = ARPHRD_PHONET_PIPE; |
09a2c3c0 RDC |
264 | dev->flags = IFF_POINTOPOINT | IFF_NOARP; |
265 | dev->mtu = GPRS_DEFAULT_MTU; | |
266 | dev->hard_header_len = 0; | |
267 | dev->addr_len = 0; | |
268 | dev->tx_queue_len = 10; | |
269 | ||
270 | dev->destructor = free_netdev; | |
271 | dev->open = gprs_open; | |
272 | dev->stop = gprs_close; | |
273 | dev->hard_start_xmit = gprs_xmit; /* mandatory */ | |
274 | dev->change_mtu = gprs_set_mtu; | |
02a47617 RDC |
275 | } |
276 | ||
277 | /* | |
278 | * External interface | |
279 | */ | |
280 | ||
281 | /* | |
282 | * Attach a GPRS interface to a datagram socket. | |
283 | * Returns the interface index on success, negative error code on error. | |
284 | */ | |
285 | int gprs_attach(struct sock *sk) | |
286 | { | |
287 | static const char ifname[] = "gprs%d"; | |
09a2c3c0 RDC |
288 | struct gprs_dev *gp; |
289 | struct net_device *dev; | |
02a47617 RDC |
290 | int err; |
291 | ||
292 | if (unlikely(sk->sk_type == SOCK_STREAM)) | |
293 | return -EINVAL; /* need packet boundaries */ | |
294 | ||
295 | /* Create net device */ | |
09a2c3c0 RDC |
296 | dev = alloc_netdev(sizeof(*gp), ifname, gprs_setup); |
297 | if (!dev) | |
02a47617 | 298 | return -ENOMEM; |
09a2c3c0 RDC |
299 | gp = netdev_priv(dev); |
300 | gp->dev = dev; | |
301 | gp->tx_max = 0; | |
302 | spin_lock_init(&gp->tx_lock); | |
303 | skb_queue_head_init(&gp->tx_queue); | |
304 | INIT_WORK(&gp->tx_work, gprs_tx); | |
305 | ||
306 | netif_stop_queue(dev); | |
307 | err = register_netdev(dev); | |
02a47617 | 308 | if (err) { |
09a2c3c0 | 309 | free_netdev(dev); |
02a47617 RDC |
310 | return err; |
311 | } | |
312 | ||
313 | lock_sock(sk); | |
314 | if (unlikely(sk->sk_user_data)) { | |
315 | err = -EBUSY; | |
316 | goto out_rel; | |
317 | } | |
318 | if (unlikely((1 << sk->sk_state & (TCPF_CLOSE|TCPF_LISTEN)) || | |
319 | sock_flag(sk, SOCK_DEAD))) { | |
320 | err = -EINVAL; | |
321 | goto out_rel; | |
322 | } | |
09a2c3c0 RDC |
323 | sk->sk_user_data = gp; |
324 | gp->old_state_change = sk->sk_state_change; | |
325 | gp->old_data_ready = sk->sk_data_ready; | |
326 | gp->old_write_space = sk->sk_write_space; | |
02a47617 RDC |
327 | sk->sk_state_change = gprs_state_change; |
328 | sk->sk_data_ready = gprs_data_ready; | |
329 | sk->sk_write_space = gprs_write_space; | |
330 | release_sock(sk); | |
331 | ||
332 | sock_hold(sk); | |
09a2c3c0 | 333 | gp->sk = sk; |
02a47617 | 334 | |
09a2c3c0 RDC |
335 | printk(KERN_DEBUG"%s: attached\n", dev->name); |
336 | return dev->ifindex; | |
02a47617 RDC |
337 | |
338 | out_rel: | |
339 | release_sock(sk); | |
09a2c3c0 | 340 | unregister_netdev(dev); |
02a47617 RDC |
341 | return err; |
342 | } | |
343 | ||
344 | void gprs_detach(struct sock *sk) | |
345 | { | |
09a2c3c0 RDC |
346 | struct gprs_dev *gp = sk->sk_user_data; |
347 | struct net_device *dev = gp->dev; | |
02a47617 RDC |
348 | |
349 | lock_sock(sk); | |
350 | sk->sk_user_data = NULL; | |
09a2c3c0 RDC |
351 | sk->sk_state_change = gp->old_state_change; |
352 | sk->sk_data_ready = gp->old_data_ready; | |
353 | sk->sk_write_space = gp->old_write_space; | |
02a47617 RDC |
354 | release_sock(sk); |
355 | ||
09a2c3c0 RDC |
356 | printk(KERN_DEBUG"%s: detached\n", dev->name); |
357 | unregister_netdev(dev); | |
02a47617 | 358 | sock_put(sk); |
02a47617 | 359 | } |