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-rw-r--r--net/phonet/pep-gprs.c347
1 files changed, 347 insertions, 0 deletions
diff --git a/net/phonet/pep-gprs.c b/net/phonet/pep-gprs.c
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index 000000000000..9978afbd9f2a
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+++ b/net/phonet/pep-gprs.c
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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
37struct 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
52static 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
74static 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
84static 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
136drop:
137 if (skb) {
138 dev_kfree_skb(skb);
139 dev->stats.rx_dropped++;
140 }
141 return err;
142}
143
144static 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
155static 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
171static 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
199static 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
230static 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
239static 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
246static 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 */
270int 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
324out_rel:
325 release_sock(sk);
326 unregister_netdev(net);
327 return err;
328}
329
330void 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}
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