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DEFINITIONS
This source file includes following definitions.
- gprs_type_trans
- gprs_state_change
- gprs_recv
- gprs_data_ready
- gprs_write_space
- gprs_xmit
- gprs_tx
- gprs_set_mtu
- gprs_get_stats
- gprs_setup
- gprs_attach
- gprs_detach
/*
* File: pep-gprs.c
*
* GPRS over Phonet pipe end point socket
*
* Copyright (C) 2008 Nokia Corporation.
*
* Author: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#include <net/sock.h>
#include <linux/if_phonet.h>
#include <net/tcp_states.h>
#include <net/phonet/gprs.h>
#define GPRS_DEFAULT_MTU 1400
struct gprs_dev {
struct sock *sk;
void (*old_state_change)(struct sock *);
void (*old_data_ready)(struct sock *, int);
void (*old_write_space)(struct sock *);
struct net_device *net;
struct net_device_stats stats;
struct sk_buff_head tx_queue;
struct work_struct tx_work;
spinlock_t tx_lock;
unsigned tx_max;
};
static int gprs_type_trans(struct sk_buff *skb)
{
const u8 *pvfc;
u8 buf;
pvfc = skb_header_pointer(skb, 0, 1, &buf);
if (!pvfc)
return 0;
/* Look at IP version field */
switch (*pvfc >> 4) {
case 4:
return htons(ETH_P_IP);
case 6:
return htons(ETH_P_IPV6);
}
return 0;
}
/*
* Socket callbacks
*/
static void gprs_state_change(struct sock *sk)
{
struct gprs_dev *dev = sk->sk_user_data;
if (sk->sk_state == TCP_CLOSE_WAIT) {
netif_stop_queue(dev->net);
netif_carrier_off(dev->net);
}
}
static int gprs_recv(struct gprs_dev *dev, struct sk_buff *skb)
{
int err = 0;
u16 protocol = gprs_type_trans(skb);
if (!protocol) {
err = -EINVAL;
goto drop;
}
if (likely(skb_headroom(skb) & 3)) {
struct sk_buff *rskb, *fs;
int flen = 0;
/* Phonet Pipe data header is misaligned (3 bytes),
* so wrap the IP packet as a single fragment of an head-less
* socket buffer. The network stack will pull what it needs,
* but at least, the whole IP payload is not memcpy'd. */
rskb = netdev_alloc_skb(dev->net, 0);
if (!rskb) {
err = -ENOBUFS;
goto drop;
}
skb_shinfo(rskb)->frag_list = skb;
rskb->len += skb->len;
rskb->data_len += rskb->len;
rskb->truesize += rskb->len;
/* Avoid nested fragments */
for (fs = skb_shinfo(skb)->frag_list; fs; fs = fs->next)
flen += fs->len;
skb->next = skb_shinfo(skb)->frag_list;
skb_shinfo(skb)->frag_list = NULL;
skb->len -= flen;
skb->data_len -= flen;
skb->truesize -= flen;
skb = rskb;
}
skb->protocol = protocol;
skb_reset_mac_header(skb);
skb->dev = dev->net;
if (likely(dev->net->flags & IFF_UP)) {
dev->stats.rx_packets++;
dev->stats.rx_bytes += skb->len;
netif_rx(skb);
skb = NULL;
} else
err = -ENODEV;
drop:
if (skb) {
dev_kfree_skb(skb);
dev->stats.rx_dropped++;
}
return err;
}
static void gprs_data_ready(struct sock *sk, int len)
{
struct gprs_dev *dev = sk->sk_user_data;
struct sk_buff *skb;
while ((skb = pep_read(sk)) != NULL) {
skb_orphan(skb);
gprs_recv(dev, skb);
}
}
static void gprs_write_space(struct sock *sk)
{
struct gprs_dev *dev = sk->sk_user_data;
unsigned credits = pep_writeable(sk);
spin_lock_bh(&dev->tx_lock);
dev->tx_max = credits;
if (credits > skb_queue_len(&dev->tx_queue))
netif_wake_queue(dev->net);
spin_unlock_bh(&dev->tx_lock);
}
/*
* Network device callbacks
*/
static int gprs_xmit(struct sk_buff *skb, struct net_device *net)
{
struct gprs_dev *dev = netdev_priv(net);
switch (skb->protocol) {
case htons(ETH_P_IP):
case htons(ETH_P_IPV6):
break;
default:
dev_kfree_skb(skb);
return 0;
}
spin_lock(&dev->tx_lock);
if (likely(skb_queue_len(&dev->tx_queue) < dev->tx_max)) {
skb_queue_tail(&dev->tx_queue, skb);
skb = NULL;
}
if (skb_queue_len(&dev->tx_queue) >= dev->tx_max)
netif_stop_queue(net);
spin_unlock(&dev->tx_lock);
schedule_work(&dev->tx_work);
if (unlikely(skb))
dev_kfree_skb(skb);
return 0;
}
static void gprs_tx(struct work_struct *work)
{
struct gprs_dev *dev = container_of(work, struct gprs_dev, tx_work);
struct sock *sk = dev->sk;
struct sk_buff *skb;
while ((skb = skb_dequeue(&dev->tx_queue)) != NULL) {
int err;
dev->stats.tx_bytes += skb->len;
dev->stats.tx_packets++;
skb_orphan(skb);
skb_set_owner_w(skb, sk);
lock_sock(sk);
err = pep_write(sk, skb);
if (err) {
LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n",
dev->net->name, err);
dev->stats.tx_aborted_errors++;
dev->stats.tx_errors++;
}
release_sock(sk);
}
lock_sock(sk);
gprs_write_space(sk);
release_sock(sk);
}
static int gprs_set_mtu(struct net_device *net, int new_mtu)
{
if ((new_mtu < 576) || (new_mtu > (PHONET_MAX_MTU - 11)))
return -EINVAL;
net->mtu = new_mtu;
return 0;
}
static struct net_device_stats *gprs_get_stats(struct net_device *net)
{
struct gprs_dev *dev = netdev_priv(net);
return &dev->stats;
}
static void gprs_setup(struct net_device *net)
{
net->features = NETIF_F_FRAGLIST;
net->type = ARPHRD_NONE;
net->flags = IFF_POINTOPOINT | IFF_NOARP;
net->mtu = GPRS_DEFAULT_MTU;
net->hard_header_len = 0;
net->addr_len = 0;
net->tx_queue_len = 10;
net->destructor = free_netdev;
net->hard_start_xmit = gprs_xmit; /* mandatory */
net->change_mtu = gprs_set_mtu;
net->get_stats = gprs_get_stats;
}
/*
* External interface
*/
/*
* Attach a GPRS interface to a datagram socket.
* Returns the interface index on success, negative error code on error.
*/
int gprs_attach(struct sock *sk)
{
static const char ifname[] = "gprs%d";
struct gprs_dev *dev;
struct net_device *net;
int err;
if (unlikely(sk->sk_type == SOCK_STREAM))
return -EINVAL; /* need packet boundaries */
/* Create net device */
net = alloc_netdev(sizeof(*dev), ifname, gprs_setup);
if (!net)
return -ENOMEM;
dev = netdev_priv(net);
dev->net = net;
dev->tx_max = 0;
spin_lock_init(&dev->tx_lock);
skb_queue_head_init(&dev->tx_queue);
INIT_WORK(&dev->tx_work, gprs_tx);
netif_stop_queue(net);
err = register_netdev(net);
if (err) {
free_netdev(net);
return err;
}
lock_sock(sk);
if (unlikely(sk->sk_user_data)) {
err = -EBUSY;
goto out_rel;
}
if (unlikely((1 << sk->sk_state & (TCPF_CLOSE|TCPF_LISTEN)) ||
sock_flag(sk, SOCK_DEAD))) {
err = -EINVAL;
goto out_rel;
}
sk->sk_user_data = dev;
dev->old_state_change = sk->sk_state_change;
dev->old_data_ready = sk->sk_data_ready;
dev->old_write_space = sk->sk_write_space;
sk->sk_state_change = gprs_state_change;
sk->sk_data_ready = gprs_data_ready;
sk->sk_write_space = gprs_write_space;
release_sock(sk);
sock_hold(sk);
dev->sk = sk;
printk(KERN_DEBUG"%s: attached\n", net->name);
gprs_write_space(sk); /* kick off TX */
return net->ifindex;
out_rel:
release_sock(sk);
unregister_netdev(net);
return err;
}
void gprs_detach(struct sock *sk)
{
struct gprs_dev *dev = sk->sk_user_data;
struct net_device *net = dev->net;
lock_sock(sk);
sk->sk_user_data = NULL;
sk->sk_state_change = dev->old_state_change;
sk->sk_data_ready = dev->old_data_ready;
sk->sk_write_space = dev->old_write_space;
release_sock(sk);
printk(KERN_DEBUG"%s: detached\n", net->name);
unregister_netdev(net);
flush_scheduled_work();
sock_put(sk);
skb_queue_purge(&dev->tx_queue);
}