4 * GPRS over Phonet pipe end point socket
6 * Copyright (C) 2008 Nokia Corporation.
8 * Author: RĂ©mi Denis-Courmont <remi.denis-courmont@nokia.com>
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.
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.
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
25 #include <linux/kernel.h>
26 #include <linux/netdevice.h>
27 #include <linux/if_ether.h>
28 #include <linux/if_arp.h>
31 #include <linux/if_phonet.h>
32 #include <net/tcp_states.h>
33 #include <net/phonet/gprs.h>
35 #define GPRS_DEFAULT_MTU 1400
39 void (*old_state_change)(struct sock *);
40 void (*old_data_ready)(struct sock *, int);
41 void (*old_write_space)(struct sock *);
43 struct net_device *dev;
45 struct sk_buff_head tx_queue;
46 struct work_struct tx_work;
51 static __be16 gprs_type_trans(struct sk_buff *skb)
56 pvfc = skb_header_pointer(skb, 0, 1, &buf);
59 /* Look at IP version field */
62 return htons(ETH_P_IP);
64 return htons(ETH_P_IPV6);
73 static void gprs_state_change(struct sock *sk)
75 struct gprs_dev *gp = sk->sk_user_data;
77 if (sk->sk_state == TCP_CLOSE_WAIT) {
78 struct net_device *dev = gp->dev;
80 netif_stop_queue(dev);
81 netif_carrier_off(dev);
85 static int gprs_recv(struct gprs_dev *gp, struct sk_buff *skb)
87 struct net_device *dev = gp->dev;
89 __be16 protocol = gprs_type_trans(skb);
96 if (likely(skb_headroom(skb) & 3)) {
97 struct sk_buff *rskb, *fs;
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. */
104 rskb = netdev_alloc_skb(dev, 0);
109 skb_shinfo(rskb)->frag_list = skb;
110 rskb->len += skb->len;
111 rskb->data_len += rskb->len;
112 rskb->truesize += rskb->len;
114 /* Avoid nested fragments */
115 for (fs = skb_shinfo(skb)->frag_list; fs; fs = fs->next)
117 skb->next = skb_shinfo(skb)->frag_list;
118 skb_shinfo(skb)->frag_list = NULL;
120 skb->data_len -= flen;
121 skb->truesize -= flen;
126 skb->protocol = protocol;
127 skb_reset_mac_header(skb);
130 if (likely(dev->flags & IFF_UP)) {
131 dev->stats.rx_packets++;
132 dev->stats.rx_bytes += skb->len;
141 dev->stats.rx_dropped++;
146 static void gprs_data_ready(struct sock *sk, int len)
148 struct gprs_dev *gp = sk->sk_user_data;
151 while ((skb = pep_read(sk)) != NULL) {
157 static void gprs_write_space(struct sock *sk)
159 struct gprs_dev *gp = sk->sk_user_data;
160 struct net_device *dev = gp->dev;
161 unsigned credits = pep_writeable(sk);
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);
171 * Network device callbacks
174 static int gprs_open(struct net_device *dev)
176 struct gprs_dev *gp = netdev_priv(dev);
178 gprs_write_space(gp->sk);
182 static int gprs_close(struct net_device *dev)
184 struct gprs_dev *gp = netdev_priv(dev);
186 netif_stop_queue(dev);
187 flush_work(&gp->tx_work);
191 static int gprs_xmit(struct sk_buff *skb, struct net_device *dev)
193 struct gprs_dev *gp = netdev_priv(dev);
195 switch (skb->protocol) {
196 case htons(ETH_P_IP):
197 case htons(ETH_P_IPV6):
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);
209 if (skb_queue_len(&gp->tx_queue) >= gp->tx_max)
210 netif_stop_queue(dev);
211 spin_unlock(&gp->tx_lock);
213 schedule_work(&gp->tx_work);
219 static void gprs_tx(struct work_struct *work)
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;
226 while ((skb = skb_dequeue(&gp->tx_queue)) != NULL) {
229 dev->stats.tx_bytes += skb->len;
230 dev->stats.tx_packets++;
233 skb_set_owner_w(skb, sk);
236 err = pep_write(sk, skb);
238 LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n",
240 dev->stats.tx_aborted_errors++;
241 dev->stats.tx_errors++;
247 gprs_write_space(sk);
251 static int gprs_set_mtu(struct net_device *dev, int new_mtu)
253 if ((new_mtu < 576) || (new_mtu > (PHONET_MAX_MTU - 11)))
260 static void gprs_setup(struct net_device *dev)
262 dev->features = NETIF_F_FRAGLIST;
263 dev->type = ARPHRD_PHONET_PIPE;
264 dev->flags = IFF_POINTOPOINT | IFF_NOARP;
265 dev->mtu = GPRS_DEFAULT_MTU;
266 dev->hard_header_len = 0;
268 dev->tx_queue_len = 10;
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;
282 * Attach a GPRS interface to a datagram socket.
283 * Returns the interface index on success, negative error code on error.
285 int gprs_attach(struct sock *sk)
287 static const char ifname[] = "gprs%d";
289 struct net_device *dev;
292 if (unlikely(sk->sk_type == SOCK_STREAM))
293 return -EINVAL; /* need packet boundaries */
295 /* Create net device */
296 dev = alloc_netdev(sizeof(*gp), ifname, gprs_setup);
299 gp = netdev_priv(dev);
302 spin_lock_init(&gp->tx_lock);
303 skb_queue_head_init(&gp->tx_queue);
304 INIT_WORK(&gp->tx_work, gprs_tx);
306 netif_stop_queue(dev);
307 err = register_netdev(dev);
314 if (unlikely(sk->sk_user_data)) {
318 if (unlikely((1 << sk->sk_state & (TCPF_CLOSE|TCPF_LISTEN)) ||
319 sock_flag(sk, SOCK_DEAD))) {
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;
327 sk->sk_state_change = gprs_state_change;
328 sk->sk_data_ready = gprs_data_ready;
329 sk->sk_write_space = gprs_write_space;
335 printk(KERN_DEBUG"%s: attached\n", dev->name);
340 unregister_netdev(dev);
344 void gprs_detach(struct sock *sk)
346 struct gprs_dev *gp = sk->sk_user_data;
347 struct net_device *dev = gp->dev;
350 sk->sk_user_data = NULL;
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;
356 printk(KERN_DEBUG"%s: detached\n", dev->name);
357 unregister_netdev(dev);