348 lines
7.5 KiB
C
348 lines
7.5 KiB
C
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/*
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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 <remi.denis-courmont@nokia.com>
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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 *, int);
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void (*old_write_space)(struct sock *);
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struct net_device *net;
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struct net_device_stats stats;
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struct sk_buff_head tx_queue;
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struct work_struct tx_work;
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spinlock_t tx_lock;
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unsigned tx_max;
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};
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static int 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 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 0;
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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 *dev = sk->sk_user_data;
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if (sk->sk_state == TCP_CLOSE_WAIT) {
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netif_stop_queue(dev->net);
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netif_carrier_off(dev->net);
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}
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}
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static int gprs_recv(struct gprs_dev *dev, struct sk_buff *skb)
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{
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int err = 0;
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u16 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 (likely(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 is 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->net, 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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for (fs = skb_shinfo(skb)->frag_list; fs; fs = fs->next)
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flen += fs->len;
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skb->next = skb_shinfo(skb)->frag_list;
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skb_shinfo(skb)->frag_list = NULL;
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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->net;
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if (likely(dev->net->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, int len)
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{
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struct gprs_dev *dev = 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(dev, 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 *dev = sk->sk_user_data;
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unsigned credits = pep_writeable(sk);
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spin_lock_bh(&dev->tx_lock);
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dev->tx_max = credits;
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if (credits > skb_queue_len(&dev->tx_queue))
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netif_wake_queue(dev->net);
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spin_unlock_bh(&dev->tx_lock);
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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_xmit(struct sk_buff *skb, struct net_device *net)
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{
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struct gprs_dev *dev = netdev_priv(net);
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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 0;
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}
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spin_lock(&dev->tx_lock);
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if (likely(skb_queue_len(&dev->tx_queue) < dev->tx_max)) {
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skb_queue_tail(&dev->tx_queue, skb);
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skb = NULL;
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}
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if (skb_queue_len(&dev->tx_queue) >= dev->tx_max)
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netif_stop_queue(net);
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spin_unlock(&dev->tx_lock);
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schedule_work(&dev->tx_work);
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if (unlikely(skb))
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dev_kfree_skb(skb);
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return 0;
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}
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static void gprs_tx(struct work_struct *work)
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{
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struct gprs_dev *dev = container_of(work, struct gprs_dev, tx_work);
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struct sock *sk = dev->sk;
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struct sk_buff *skb;
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while ((skb = skb_dequeue(&dev->tx_queue)) != NULL) {
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int err;
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dev->stats.tx_bytes += skb->len;
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dev->stats.tx_packets++;
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skb_orphan(skb);
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skb_set_owner_w(skb, sk);
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lock_sock(sk);
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err = pep_write(sk, skb);
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if (err) {
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LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n",
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dev->net->name, err);
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dev->stats.tx_aborted_errors++;
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dev->stats.tx_errors++;
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}
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release_sock(sk);
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}
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lock_sock(sk);
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gprs_write_space(sk);
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release_sock(sk);
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}
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static int gprs_set_mtu(struct net_device *net, int new_mtu)
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{
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if ((new_mtu < 576) || (new_mtu > (PHONET_MAX_MTU - 11)))
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return -EINVAL;
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net->mtu = new_mtu;
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return 0;
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}
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static struct net_device_stats *gprs_get_stats(struct net_device *net)
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{
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struct gprs_dev *dev = netdev_priv(net);
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return &dev->stats;
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}
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static void gprs_setup(struct net_device *net)
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{
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net->features = NETIF_F_FRAGLIST;
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net->type = ARPHRD_NONE;
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net->flags = IFF_POINTOPOINT | IFF_NOARP;
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net->mtu = GPRS_DEFAULT_MTU;
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net->hard_header_len = 0;
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net->addr_len = 0;
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net->tx_queue_len = 10;
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net->destructor = free_netdev;
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net->hard_start_xmit = gprs_xmit; /* mandatory */
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net->change_mtu = gprs_set_mtu;
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net->get_stats = gprs_get_stats;
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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 *dev;
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struct net_device *net;
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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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net = alloc_netdev(sizeof(*dev), ifname, gprs_setup);
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if (!net)
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return -ENOMEM;
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dev = netdev_priv(net);
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dev->net = net;
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dev->tx_max = 0;
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spin_lock_init(&dev->tx_lock);
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skb_queue_head_init(&dev->tx_queue);
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INIT_WORK(&dev->tx_work, gprs_tx);
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netif_stop_queue(net);
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err = register_netdev(net);
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if (err) {
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free_netdev(net);
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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 = dev;
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dev->old_state_change = sk->sk_state_change;
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dev->old_data_ready = sk->sk_data_ready;
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dev->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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dev->sk = sk;
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printk(KERN_DEBUG"%s: attached\n", net->name);
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gprs_write_space(sk); /* kick off TX */
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return net->ifindex;
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out_rel:
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release_sock(sk);
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unregister_netdev(net);
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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 *dev = sk->sk_user_data;
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struct net_device *net = dev->net;
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lock_sock(sk);
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sk->sk_user_data = NULL;
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sk->sk_state_change = dev->old_state_change;
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sk->sk_data_ready = dev->old_data_ready;
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sk->sk_write_space = dev->old_write_space;
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release_sock(sk);
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printk(KERN_DEBUG"%s: detached\n", net->name);
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unregister_netdev(net);
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flush_scheduled_work();
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sock_put(sk);
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skb_queue_purge(&dev->tx_queue);
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}
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