320 lines
6.6 KiB
C
320 lines
6.6 KiB
C
/*
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* File: pep-gprs.c
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*
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* GPRS over Phonet pipe end point socket
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*
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* Copyright (C) 2008 Nokia Corporation.
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*
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* Author: Rémi Denis-Courmont
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*/
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/if_ether.h>
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#include <linux/if_arp.h>
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#include <net/sock.h>
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#include <linux/if_phonet.h>
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#include <net/tcp_states.h>
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#include <net/phonet/gprs.h>
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#define GPRS_DEFAULT_MTU 1400
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struct gprs_dev {
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struct sock *sk;
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void (*old_state_change)(struct sock *);
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void (*old_data_ready)(struct sock *);
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void (*old_write_space)(struct sock *);
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struct net_device *dev;
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};
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static __be16 gprs_type_trans(struct sk_buff *skb)
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{
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const u8 *pvfc;
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u8 buf;
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pvfc = skb_header_pointer(skb, 0, 1, &buf);
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if (!pvfc)
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return htons(0);
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/* Look at IP version field */
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switch (*pvfc >> 4) {
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case 4:
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return htons(ETH_P_IP);
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case 6:
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return htons(ETH_P_IPV6);
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}
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return htons(0);
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}
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static void gprs_writeable(struct gprs_dev *gp)
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{
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struct net_device *dev = gp->dev;
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if (pep_writeable(gp->sk))
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netif_wake_queue(dev);
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}
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/*
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* Socket callbacks
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*/
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static void gprs_state_change(struct sock *sk)
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{
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struct gprs_dev *gp = sk->sk_user_data;
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if (sk->sk_state == TCP_CLOSE_WAIT) {
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struct net_device *dev = gp->dev;
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netif_stop_queue(dev);
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netif_carrier_off(dev);
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}
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}
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static int gprs_recv(struct gprs_dev *gp, struct sk_buff *skb)
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{
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struct net_device *dev = gp->dev;
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int err = 0;
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__be16 protocol = gprs_type_trans(skb);
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if (!protocol) {
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err = -EINVAL;
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goto drop;
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}
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if (skb_headroom(skb) & 3) {
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struct sk_buff *rskb, *fs;
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int flen = 0;
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/* Phonet Pipe data header may be misaligned (3 bytes),
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* so wrap the IP packet as a single fragment of an head-less
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* socket buffer. The network stack will pull what it needs,
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* but at least, the whole IP payload is not memcpy'd. */
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rskb = netdev_alloc_skb(dev, 0);
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if (!rskb) {
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err = -ENOBUFS;
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goto drop;
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}
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skb_shinfo(rskb)->frag_list = skb;
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rskb->len += skb->len;
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rskb->data_len += rskb->len;
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rskb->truesize += rskb->len;
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/* Avoid nested fragments */
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skb_walk_frags(skb, fs)
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flen += fs->len;
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skb->next = skb_shinfo(skb)->frag_list;
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skb_frag_list_init(skb);
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skb->len -= flen;
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skb->data_len -= flen;
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skb->truesize -= flen;
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skb = rskb;
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}
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skb->protocol = protocol;
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skb_reset_mac_header(skb);
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skb->dev = dev;
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if (likely(dev->flags & IFF_UP)) {
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dev->stats.rx_packets++;
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dev->stats.rx_bytes += skb->len;
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netif_rx(skb);
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skb = NULL;
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} else
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err = -ENODEV;
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drop:
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if (skb) {
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dev_kfree_skb(skb);
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dev->stats.rx_dropped++;
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}
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return err;
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}
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static void gprs_data_ready(struct sock *sk)
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{
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struct gprs_dev *gp = sk->sk_user_data;
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struct sk_buff *skb;
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while ((skb = pep_read(sk)) != NULL) {
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skb_orphan(skb);
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gprs_recv(gp, skb);
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}
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}
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static void gprs_write_space(struct sock *sk)
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{
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struct gprs_dev *gp = sk->sk_user_data;
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if (netif_running(gp->dev))
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gprs_writeable(gp);
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}
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/*
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* Network device callbacks
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*/
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static int gprs_open(struct net_device *dev)
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{
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struct gprs_dev *gp = netdev_priv(dev);
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gprs_writeable(gp);
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return 0;
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}
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static int gprs_close(struct net_device *dev)
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{
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netif_stop_queue(dev);
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return 0;
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}
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static netdev_tx_t gprs_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct gprs_dev *gp = netdev_priv(dev);
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struct sock *sk = gp->sk;
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int len, err;
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switch (skb->protocol) {
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case htons(ETH_P_IP):
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case htons(ETH_P_IPV6):
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break;
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default:
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dev_kfree_skb(skb);
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return NETDEV_TX_OK;
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}
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skb_orphan(skb);
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skb_set_owner_w(skb, sk);
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len = skb->len;
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err = pep_write(sk, skb);
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if (err) {
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net_dbg_ratelimited("%s: TX error (%d)\n", dev->name, err);
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dev->stats.tx_aborted_errors++;
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dev->stats.tx_errors++;
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} else {
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dev->stats.tx_packets++;
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dev->stats.tx_bytes += len;
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}
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netif_stop_queue(dev);
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if (pep_writeable(sk))
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netif_wake_queue(dev);
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return NETDEV_TX_OK;
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}
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static const struct net_device_ops gprs_netdev_ops = {
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.ndo_open = gprs_open,
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.ndo_stop = gprs_close,
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.ndo_start_xmit = gprs_xmit,
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};
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static void gprs_setup(struct net_device *dev)
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{
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dev->features = NETIF_F_FRAGLIST;
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dev->type = ARPHRD_PHONET_PIPE;
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dev->flags = IFF_POINTOPOINT | IFF_NOARP;
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dev->mtu = GPRS_DEFAULT_MTU;
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dev->min_mtu = 576;
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dev->max_mtu = (PHONET_MAX_MTU - 11);
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dev->hard_header_len = 0;
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dev->addr_len = 0;
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dev->tx_queue_len = 10;
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dev->netdev_ops = &gprs_netdev_ops;
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dev->needs_free_netdev = true;
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}
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/*
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* External interface
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*/
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/*
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* Attach a GPRS interface to a datagram socket.
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* Returns the interface index on success, negative error code on error.
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*/
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int gprs_attach(struct sock *sk)
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{
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static const char ifname[] = "gprs%d";
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struct gprs_dev *gp;
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struct net_device *dev;
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int err;
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if (unlikely(sk->sk_type == SOCK_STREAM))
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return -EINVAL; /* need packet boundaries */
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/* Create net device */
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dev = alloc_netdev(sizeof(*gp), ifname, NET_NAME_UNKNOWN, gprs_setup);
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if (!dev)
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return -ENOMEM;
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gp = netdev_priv(dev);
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gp->sk = sk;
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gp->dev = dev;
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netif_stop_queue(dev);
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err = register_netdev(dev);
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if (err) {
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free_netdev(dev);
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return err;
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}
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lock_sock(sk);
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if (unlikely(sk->sk_user_data)) {
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err = -EBUSY;
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goto out_rel;
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}
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if (unlikely((1 << sk->sk_state & (TCPF_CLOSE|TCPF_LISTEN)) ||
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sock_flag(sk, SOCK_DEAD))) {
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err = -EINVAL;
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goto out_rel;
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}
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sk->sk_user_data = gp;
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gp->old_state_change = sk->sk_state_change;
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gp->old_data_ready = sk->sk_data_ready;
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gp->old_write_space = sk->sk_write_space;
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sk->sk_state_change = gprs_state_change;
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sk->sk_data_ready = gprs_data_ready;
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sk->sk_write_space = gprs_write_space;
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release_sock(sk);
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sock_hold(sk);
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printk(KERN_DEBUG"%s: attached\n", dev->name);
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return dev->ifindex;
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out_rel:
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release_sock(sk);
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unregister_netdev(dev);
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return err;
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}
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void gprs_detach(struct sock *sk)
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{
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struct gprs_dev *gp = sk->sk_user_data;
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struct net_device *dev = gp->dev;
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lock_sock(sk);
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sk->sk_user_data = NULL;
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sk->sk_state_change = gp->old_state_change;
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sk->sk_data_ready = gp->old_data_ready;
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sk->sk_write_space = gp->old_write_space;
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release_sock(sk);
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printk(KERN_DEBUG"%s: detached\n", dev->name);
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unregister_netdev(dev);
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sock_put(sk);
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}
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