[deliverable/linux.git] / net / phonet / pep-gprs.c

/*
 * 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;

	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 *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;
	struct net_device *dev = gp->dev;
	unsigned credits = pep_writeable(sk);

	spin_lock_bh(&gp->tx_lock);
	gp->tx_max = credits;
	if (credits > skb_queue_len(&gp->tx_queue) && netif_running(dev))
		netif_wake_queue(dev);
	spin_unlock_bh(&gp->tx_lock);
}

/*
 * Network device callbacks
 */

static int gprs_open(struct net_device *dev)
{
	struct gprs_dev *gp = netdev_priv(dev);

	gprs_write_space(gp->sk);
	return 0;
}

static int gprs_close(struct net_device *dev)
{
	struct gprs_dev *gp = netdev_priv(dev);

	netif_stop_queue(dev);
	flush_work(&gp->tx_work);
	return 0;
}

static int gprs_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct gprs_dev *gp = netdev_priv(dev);

	switch (skb->protocol) {
	case  htons(ETH_P_IP):
	case  htons(ETH_P_IPV6):
		break;
	default:
		dev_kfree_skb(skb);
		return 0;
	}

	spin_lock(&gp->tx_lock);
	if (likely(skb_queue_len(&gp->tx_queue) < gp->tx_max)) {
		skb_queue_tail(&gp->tx_queue, skb);
		skb = NULL;
	}
	if (skb_queue_len(&gp->tx_queue) >= gp->tx_max)
		netif_stop_queue(dev);
	spin_unlock(&gp->tx_lock);

	schedule_work(&gp->tx_work);
	if (unlikely(skb))
		dev_kfree_skb(skb);
	return 0;
}

static void gprs_tx(struct work_struct *work)
{
	struct gprs_dev *gp = container_of(work, struct gprs_dev, tx_work);
	struct net_device *dev = gp->dev;
	struct sock *sk = gp->sk;
	struct sk_buff *skb;

	while ((skb = skb_dequeue(&gp->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->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 *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->dev = dev;
	gp->tx_max = 0;
	spin_lock_init(&gp->tx_lock);
	skb_queue_head_init(&gp->tx_queue);
	INIT_WORK(&gp->tx_work, gprs_tx);

	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);
	gp->sk = 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);
}
Commit	Line	Data
02a47617 RDC	1	/*
	2	* File: pep-gprs.c
	3	*
	4	* GPRS over Phonet pipe end point socket
	5	*
	6	* Copyright (C) 2008 Nokia Corporation.
	7	*
	8	* Author: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
	9	*
	10	* This program is free software; you can redistribute it and/or
	11	* modify it under the terms of the GNU General Public License
	12	* version 2 as published by the Free Software Foundation.
	13	*
	14	* This program is distributed in the hope that it will be useful, but
	15	* WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	17	* General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU General Public License
	20	* along with this program; if not, write to the Free Software
	21	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
	22	* 02110-1301 USA
	23	*/
	24
	25	#include <linux/kernel.h>
	26	#include <linux/netdevice.h>
	27	#include <linux/if_ether.h>
	28	#include <linux/if_arp.h>
	29	#include <net/sock.h>
	30
	31	#include <linux/if_phonet.h>
	32	#include <net/tcp_states.h>
	33	#include <net/phonet/gprs.h>
	34
	35	#define GPRS_DEFAULT_MTU 1400
	36
	37	struct gprs_dev {
	38	struct sock *sk;
	39	void (old_state_change)(struct sock );
	40	void (old_data_ready)(struct sock , int);
	41	void (old_write_space)(struct sock );
	42
09a2c3c0	43	struct net_device *dev;
02a47617 RDC	44
	45	struct sk_buff_head tx_queue;
	46	struct work_struct tx_work;
	47	spinlock_t tx_lock;
	48	unsigned tx_max;
	49	};
	50
5c7f0333	51	static __be16 gprs_type_trans(struct sk_buff *skb)
02a47617 RDC	52	{
	53	const u8 *pvfc;
	54	u8 buf;
	55
	56	pvfc = skb_header_pointer(skb, 0, 1, &buf);
	57	if (!pvfc)
5c7f0333	58	return htons(0);
02a47617 RDC	59	/* Look at IP version field */
	60	switch (*pvfc >> 4) {
	61	case 4:
	62	return htons(ETH_P_IP);
	63	case 6:
	64	return htons(ETH_P_IPV6);
	65	}
5c7f0333	66	return htons(0);
02a47617 RDC	67	}
	68
	69	/*
	70	* Socket callbacks
	71	*/
	72
	73	static void gprs_state_change(struct sock *sk)
	74	{
09a2c3c0	75	struct gprs_dev *gp = sk->sk_user_data;
02a47617 RDC	76
02a47617 RDC	77	if (sk->sk_state == TCP_CLOSE_WAIT) {
09a2c3c0 RDC	78	struct net_device *dev = gp->dev;
	79
	80	netif_stop_queue(dev);
	81	netif_carrier_off(dev);
02a47617 RDC	82	}
	83	}
	84
09a2c3c0	85	static int gprs_recv(struct gprs_dev gp, struct sk_buff skb)
02a47617	86	{
09a2c3c0	87	struct net_device *dev = gp->dev;
02a47617	88	int err = 0;
5c7f0333	89	__be16 protocol = gprs_type_trans(skb);
02a47617 RDC	90
	91	if (!protocol) {
	92	err = -EINVAL;
	93	goto drop;
	94	}
	95
	96	if (likely(skb_headroom(skb) & 3)) {
	97	struct sk_buff rskb, fs;
	98	int flen = 0;
	99
	100	/* Phonet Pipe data header is misaligned (3 bytes),
	101	* so wrap the IP packet as a single fragment of an head-less
	102	* socket buffer. The network stack will pull what it needs,
	103	* but at least, the whole IP payload is not memcpy'd. */
09a2c3c0	104	rskb = netdev_alloc_skb(dev, 0);
02a47617 RDC	105	if (!rskb) {
	106	err = -ENOBUFS;
	107	goto drop;
	108	}
	109	skb_shinfo(rskb)->frag_list = skb;
	110	rskb->len += skb->len;
	111	rskb->data_len += rskb->len;
	112	rskb->truesize += rskb->len;
	113
	114	/* Avoid nested fragments */
	115	for (fs = skb_shinfo(skb)->frag_list; fs; fs = fs->next)
	116	flen += fs->len;
	117	skb->next = skb_shinfo(skb)->frag_list;
	118	skb_shinfo(skb)->frag_list = NULL;
	119	skb->len -= flen;
	120	skb->data_len -= flen;
	121	skb->truesize -= flen;
	122
	123	skb = rskb;
	124	}
	125
	126	skb->protocol = protocol;
	127	skb_reset_mac_header(skb);
09a2c3c0	128	skb->dev = dev;
02a47617	129
09a2c3c0 RDC	130	if (likely(dev->flags & IFF_UP)) {
	131	dev->stats.rx_packets++;
	132	dev->stats.rx_bytes += skb->len;
02a47617 RDC	133	netif_rx(skb);
	134	skb = NULL;
	135	} else
	136	err = -ENODEV;
	137
	138	drop:
	139	if (skb) {
	140	dev_kfree_skb(skb);
09a2c3c0	141	dev->stats.rx_dropped++;
02a47617 RDC	142	}
	143	return err;
	144	}
	145
	146	static void gprs_data_ready(struct sock *sk, int len)
	147	{
09a2c3c0	148	struct gprs_dev *gp = sk->sk_user_data;
02a47617 RDC	149	struct sk_buff *skb;
	150
	151	while ((skb = pep_read(sk)) != NULL) {
	152	skb_orphan(skb);
09a2c3c0	153	gprs_recv(gp, skb);
02a47617 RDC	154	}
	155	}
	156
	157	static void gprs_write_space(struct sock *sk)
	158	{
09a2c3c0 RDC	159	struct gprs_dev *gp = sk->sk_user_data;
09a2c3c0 RDC	160	struct net_device *dev = gp->dev;
02a47617 RDC	161	unsigned credits = pep_writeable(sk);
02a47617 RDC	162
09a2c3c0 RDC	163	spin_lock_bh(&gp->tx_lock);
	164	gp->tx_max = credits;
	165	if (credits > skb_queue_len(&gp->tx_queue) && netif_running(dev))
	166	netif_wake_queue(dev);
	167	spin_unlock_bh(&gp->tx_lock);
02a47617 RDC	168	}
	169
	170	/*
	171	* Network device callbacks
	172	*/
	173
4798a2b8 RDC	174	static int gprs_open(struct net_device *dev)
	175	{
	176	struct gprs_dev *gp = netdev_priv(dev);
	177
	178	gprs_write_space(gp->sk);
	179	return 0;
	180	}
	181
	182	static int gprs_close(struct net_device *dev)
	183	{
	184	struct gprs_dev *gp = netdev_priv(dev);
	185
	186	netif_stop_queue(dev);
	187	flush_work(&gp->tx_work);
	188	return 0;
	189	}
	190
09a2c3c0	191	static int gprs_xmit(struct sk_buff skb, struct net_device dev)
02a47617	192	{
09a2c3c0	193	struct gprs_dev *gp = netdev_priv(dev);
02a47617 RDC	194
	195	switch (skb->protocol) {
	196	case htons(ETH_P_IP):
	197	case htons(ETH_P_IPV6):
	198	break;
	199	default:
	200	dev_kfree_skb(skb);
	201	return 0;
	202	}
	203
09a2c3c0 RDC	204	spin_lock(&gp->tx_lock);
	205	if (likely(skb_queue_len(&gp->tx_queue) < gp->tx_max)) {
	206	skb_queue_tail(&gp->tx_queue, skb);
02a47617 RDC	207	skb = NULL;
02a47617 RDC	208	}
09a2c3c0 RDC	209	if (skb_queue_len(&gp->tx_queue) >= gp->tx_max)
	210	netif_stop_queue(dev);
	211	spin_unlock(&gp->tx_lock);
02a47617	212
09a2c3c0	213	schedule_work(&gp->tx_work);
02a47617 RDC	214	if (unlikely(skb))
	215	dev_kfree_skb(skb);
	216	return 0;
	217	}
	218
	219	static void gprs_tx(struct work_struct *work)
	220	{
09a2c3c0 RDC	221	struct gprs_dev *gp = container_of(work, struct gprs_dev, tx_work);
	222	struct net_device *dev = gp->dev;
	223	struct sock *sk = gp->sk;
02a47617 RDC	224	struct sk_buff *skb;
02a47617 RDC	225
09a2c3c0	226	while ((skb = skb_dequeue(&gp->tx_queue)) != NULL) {
02a47617 RDC	227	int err;
02a47617 RDC	228
09a2c3c0 RDC	229	dev->stats.tx_bytes += skb->len;
09a2c3c0 RDC	230	dev->stats.tx_packets++;
02a47617 RDC	231
	232	skb_orphan(skb);
	233	skb_set_owner_w(skb, sk);
	234
	235	lock_sock(sk);
	236	err = pep_write(sk, skb);
	237	if (err) {
	238	LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n",
09a2c3c0 RDC	239	dev->name, err);
	240	dev->stats.tx_aborted_errors++;
	241	dev->stats.tx_errors++;
02a47617 RDC	242	}
	243	release_sock(sk);
	244	}
	245
	246	lock_sock(sk);
	247	gprs_write_space(sk);
	248	release_sock(sk);
	249	}
	250
09a2c3c0	251	static int gprs_set_mtu(struct net_device *dev, int new_mtu)
02a47617 RDC	252	{
	253	if ((new_mtu < 576) \|\| (new_mtu > (PHONET_MAX_MTU - 11)))
	254	return -EINVAL;
	255
09a2c3c0	256	dev->mtu = new_mtu;
02a47617 RDC	257	return 0;
	258	}
	259
09a2c3c0	260	static void gprs_setup(struct net_device *dev)
02a47617	261	{
09a2c3c0	262	dev->features = NETIF_F_FRAGLIST;
57c81fff	263	dev->type = ARPHRD_PHONET_PIPE;
09a2c3c0 RDC	264	dev->flags = IFF_POINTOPOINT \| IFF_NOARP;
	265	dev->mtu = GPRS_DEFAULT_MTU;
	266	dev->hard_header_len = 0;
	267	dev->addr_len = 0;
	268	dev->tx_queue_len = 10;
	269
	270	dev->destructor = free_netdev;
	271	dev->open = gprs_open;
	272	dev->stop = gprs_close;
	273	dev->hard_start_xmit = gprs_xmit; /* mandatory */
	274	dev->change_mtu = gprs_set_mtu;
02a47617 RDC	275	}
	276
	277	/*
	278	* External interface
	279	*/
	280
	281	/*
	282	* Attach a GPRS interface to a datagram socket.
	283	* Returns the interface index on success, negative error code on error.
	284	*/
	285	int gprs_attach(struct sock *sk)
	286	{
	287	static const char ifname[] = "gprs%d";
09a2c3c0 RDC	288	struct gprs_dev *gp;
09a2c3c0 RDC	289	struct net_device *dev;
02a47617 RDC	290	int err;
	291
	292	if (unlikely(sk->sk_type == SOCK_STREAM))
	293	return -EINVAL; /* need packet boundaries */
	294
	295	/* Create net device */
09a2c3c0 RDC	296	dev = alloc_netdev(sizeof(*gp), ifname, gprs_setup);
09a2c3c0 RDC	297	if (!dev)
02a47617	298	return -ENOMEM;
09a2c3c0 RDC	299	gp = netdev_priv(dev);
	300	gp->dev = dev;
	301	gp->tx_max = 0;
	302	spin_lock_init(&gp->tx_lock);
	303	skb_queue_head_init(&gp->tx_queue);
	304	INIT_WORK(&gp->tx_work, gprs_tx);
	305
	306	netif_stop_queue(dev);
	307	err = register_netdev(dev);
02a47617	308	if (err) {
09a2c3c0	309	free_netdev(dev);
02a47617 RDC	310	return err;
	311	}
	312
	313	lock_sock(sk);
	314	if (unlikely(sk->sk_user_data)) {
	315	err = -EBUSY;
	316	goto out_rel;
	317	}
	318	if (unlikely((1 << sk->sk_state & (TCPF_CLOSE\|TCPF_LISTEN)) \|\|
	319	sock_flag(sk, SOCK_DEAD))) {
	320	err = -EINVAL;
	321	goto out_rel;
	322	}
09a2c3c0 RDC	323	sk->sk_user_data = gp;
	324	gp->old_state_change = sk->sk_state_change;
	325	gp->old_data_ready = sk->sk_data_ready;
	326	gp->old_write_space = sk->sk_write_space;
02a47617 RDC	327	sk->sk_state_change = gprs_state_change;
	328	sk->sk_data_ready = gprs_data_ready;
	329	sk->sk_write_space = gprs_write_space;
	330	release_sock(sk);
	331
	332	sock_hold(sk);
09a2c3c0	333	gp->sk = sk;
02a47617	334
09a2c3c0 RDC	335	printk(KERN_DEBUG"%s: attached\n", dev->name);
09a2c3c0 RDC	336	return dev->ifindex;
02a47617 RDC	337
	338	out_rel:
	339	release_sock(sk);
09a2c3c0	340	unregister_netdev(dev);
02a47617 RDC	341	return err;
	342	}
	343
	344	void gprs_detach(struct sock *sk)
	345	{
09a2c3c0 RDC	346	struct gprs_dev *gp = sk->sk_user_data;
09a2c3c0 RDC	347	struct net_device *dev = gp->dev;
02a47617 RDC	348
	349	lock_sock(sk);
	350	sk->sk_user_data = NULL;
09a2c3c0 RDC	351	sk->sk_state_change = gp->old_state_change;
	352	sk->sk_data_ready = gp->old_data_ready;
	353	sk->sk_write_space = gp->old_write_space;
02a47617 RDC	354	release_sock(sk);
02a47617 RDC	355
09a2c3c0 RDC	356	printk(KERN_DEBUG"%s: detached\n", dev->name);
09a2c3c0 RDC	357	unregister_netdev(dev);
02a47617	358	sock_put(sk);
02a47617	359	}