net/phonet/pep-gprs.c - kernel/msm-4.19 - Gitiles

 /*
  * 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 __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);
 }

 /*
  * 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;
 	__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->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);
 }
	/*
	* 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 __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);
	}

	/*
	* 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;
	__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->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);
	}