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/*
* 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 *dev;
};
static __be16 gprs_type_trans(struct sk_buff *skb)
{
const u8 *pvfc;
u8 buf;
pvfc = skb_header_pointer(skb, 0, 1, &buf);
if (!pvfc)
return htons(0);
/* Look at IP version field */
switch (*pvfc >> 4) {
case 4:
return htons(ETH_P_IP);
case 6:
return htons(ETH_P_IPV6);
}
return htons(0);
}
static void gprs_writeable(struct gprs_dev *gp)
{
struct net_device *dev = gp->dev;
if (pep_writeable(gp->sk))
netif_wake_queue(dev);
}
/*
* Socket callbacks
*/
static void gprs_state_change(struct sock *sk)
{
struct gprs_dev *gp = sk->sk_user_data;
if (sk->sk_state == TCP_CLOSE_WAIT) {
struct net_device *dev = gp->dev;
netif_stop_queue(dev);
netif_carrier_off(dev);
}
}
static int gprs_recv(struct gprs_dev *gp, struct sk_buff *skb)
{
struct net_device *dev = gp->dev;
int err = 0;
__be16 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, 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;
if (likely(dev->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 *gp = sk->sk_user_data;
struct sk_buff *skb;
while ((skb = pep_read(sk)) != NULL) {
skb_orphan(skb);
gprs_recv(gp, skb);
}
}
static void gprs_write_space(struct sock *sk)
{
struct gprs_dev *gp = sk->sk_user_data;
if (netif_running(gp->dev))
gprs_writeable(gp);
}
/*
* Network device callbacks
*/
static int gprs_open(struct net_device *dev)
{
struct gprs_dev *gp = netdev_priv(dev);
gprs_writeable(gp);
return 0;
}
static int gprs_close(struct net_device *dev)
{
netif_stop_queue(dev);
return 0;
}
static int gprs_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct gprs_dev *gp = netdev_priv(dev);
struct sock *sk = gp->sk;
int len, err;
switch (skb->protocol) {
case htons(ETH_P_IP):
case htons(ETH_P_IPV6):
break;
default:
dev_kfree_skb(skb);
return 0;
}
skb_orphan(skb);
skb_set_owner_w(skb, sk);
len = skb->len;
err = pep_write(sk, skb);
if (err) {
LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n",
dev->name, err);
dev->stats.tx_aborted_errors++;
dev->stats.tx_errors++;
dev_kfree_skb(skb);
} else {
dev->stats.tx_packets++;
dev->stats.tx_bytes += len;
}
if (!pep_writeable(sk))
netif_stop_queue(dev);
return 0;
}
static int gprs_set_mtu(struct net_device *dev, int new_mtu)
{
if ((new_mtu < 576) || (new_mtu > (PHONET_MAX_MTU - 11)))
return -EINVAL;
dev->mtu = new_mtu;
return 0;
}
static void gprs_setup(struct net_device *dev)
{
dev->features = NETIF_F_FRAGLIST;
dev->type = ARPHRD_PHONET_PIPE;
dev->flags = IFF_POINTOPOINT | IFF_NOARP;
dev->mtu = GPRS_DEFAULT_MTU;
dev->hard_header_len = 0;
dev->addr_len = 0;
dev->tx_queue_len = 10;
dev->destructor = free_netdev;
dev->open = gprs_open;
dev->stop = gprs_close;
dev->hard_start_xmit = gprs_xmit; /* mandatory */
dev->change_mtu = gprs_set_mtu;
}
/*
* 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 *gp;
struct net_device *dev;
int err;
if (unlikely(sk->sk_type == SOCK_STREAM))
return -EINVAL; /* need packet boundaries */
/* Create net device */
dev = alloc_netdev(sizeof(*gp), ifname, gprs_setup);
if (!dev)
return -ENOMEM;
gp = netdev_priv(dev);
gp->sk = sk;
gp->dev = dev;
netif_stop_queue(dev);
err = register_netdev(dev);
if (err) {
free_netdev(dev);
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 = gp;
gp->old_state_change = sk->sk_state_change;
gp->old_data_ready = sk->sk_data_ready;
gp->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);
printk(KERN_DEBUG"%s: attached\n", dev->name);
return dev->ifindex;
out_rel:
release_sock(sk);
unregister_netdev(dev);
return err;
}
void gprs_detach(struct sock *sk)
{
struct gprs_dev *gp = sk->sk_user_data;
struct net_device *dev = gp->dev;
lock_sock(sk);
sk->sk_user_data = NULL;
sk->sk_state_change = gp->old_state_change;
sk->sk_data_ready = gp->old_data_ready;
sk->sk_write_space = gp->old_write_space;
release_sock(sk);
printk(KERN_DEBUG"%s: detached\n", dev->name);
unregister_netdev(dev);
sock_put(sk);
}
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