[mirror_ubuntu-zesty-kernel.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	*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 int gprs_type_trans(struct sk_buff *skb)
{
	const u8 *pvfc;
	u8 buf;

	pvfc = skb_header_pointer(skb, 0, 1, &buf);
	if (!pvfc)
		return 0;
	/* Look at IP version field */
	switch (*pvfc >> 4) {
	case 4:
		return htons(ETH_P_IP);
	case 6:
		return htons(ETH_P_IPV6);
	}
	return 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;
	u16 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;
	struct net_device *net = dev->net;
	unsigned credits = pep_writeable(sk);

	spin_lock_bh(&dev->tx_lock);
	dev->tx_max = credits;
	if (credits > skb_queue_len(&dev->tx_queue) && netif_running(net))
		netif_wake_queue(net);
	spin_unlock_bh(&dev->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 *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->open		= gprs_open;
	net->stop		= gprs_close;
	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);
	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);
	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
	43	struct net_device *net;
	44	struct net_device_stats stats;
	45
	46	struct sk_buff_head tx_queue;
	47	struct work_struct tx_work;
	48	spinlock_t tx_lock;
	49	unsigned tx_max;
	50	};
	51
	52	static int gprs_type_trans(struct sk_buff *skb)
	53	{
	54	const u8 *pvfc;
	55	u8 buf;
	56
	57	pvfc = skb_header_pointer(skb, 0, 1, &buf);
	58	if (!pvfc)
	59	return 0;
	60	/* Look at IP version field */
	61	switch (*pvfc >> 4) {
	62	case 4:
	63	return htons(ETH_P_IP);
	64	case 6:
65	return htons(ETH_P_IPV6);
66	}
67	return 0;
68	}
69
70	/*
71	* Socket callbacks
72	*/
73
74	static void gprs_state_change(struct sock *sk)
75	{
76	struct gprs_dev *dev = sk->sk_user_data;
77
78	if (sk->sk_state == TCP_CLOSE_WAIT) {
79	netif_stop_queue(dev->net);
80	netif_carrier_off(dev->net);
81	}
82	}
83
84	static int gprs_recv(struct gprs_dev dev, struct sk_buff skb)
85	{
86	int err = 0;
87	u16 protocol = gprs_type_trans(skb);
88
89	if (!protocol) {
90	err = -EINVAL;
91	goto drop;
92	}
93
94	if (likely(skb_headroom(skb) & 3)) {
95	struct sk_buff rskb, fs;
96	int flen = 0;
97
98	/* Phonet Pipe data header is misaligned (3 bytes),
99	* so wrap the IP packet as a single fragment of an head-less
100	* socket buffer. The network stack will pull what it needs,
101	* but at least, the whole IP payload is not memcpy'd. */
102	rskb = netdev_alloc_skb(dev->net, 0);
103	if (!rskb) {
104	err = -ENOBUFS;
105	goto drop;
106	}
107	skb_shinfo(rskb)->frag_list = skb;
108	rskb->len += skb->len;
109	rskb->data_len += rskb->len;
110	rskb->truesize += rskb->len;
111
112	/* Avoid nested fragments */
113	for (fs = skb_shinfo(skb)->frag_list; fs; fs = fs->next)
114	flen += fs->len;
115	skb->next = skb_shinfo(skb)->frag_list;
116	skb_shinfo(skb)->frag_list = NULL;
117	skb->len -= flen;
118	skb->data_len -= flen;
119	skb->truesize -= flen;
120
121	skb = rskb;
122	}
123
124	skb->protocol = protocol;
125	skb_reset_mac_header(skb);
126	skb->dev = dev->net;
127
128	if (likely(dev->net->flags & IFF_UP)) {
129	dev->stats.rx_packets++;
130	dev->stats.rx_bytes += skb->len;
131	netif_rx(skb);
132	skb = NULL;
133	} else
134	err = -ENODEV;
135
136	drop:
137	if (skb) {
138	dev_kfree_skb(skb);
139	dev->stats.rx_dropped++;
140	}
141	return err;
142	}
143
144	static void gprs_data_ready(struct sock *sk, int len)
145	{
146	struct gprs_dev *dev = sk->sk_user_data;
147	struct sk_buff *skb;
148
149	while ((skb = pep_read(sk)) != NULL) {
150	skb_orphan(skb);
151	gprs_recv(dev, skb);
152	}
153	}
154
155	static void gprs_write_space(struct sock *sk)
156	{
157	struct gprs_dev *dev = sk->sk_user_data;
4798a2b8	158	struct net_device *net = dev->net;
02a47617 RDC	159	unsigned credits = pep_writeable(sk);
	160
	161	spin_lock_bh(&dev->tx_lock);
	162	dev->tx_max = credits;
4798a2b8 RDC	163	if (credits > skb_queue_len(&dev->tx_queue) && netif_running(net))
4798a2b8 RDC	164	netif_wake_queue(net);
02a47617 RDC	165	spin_unlock_bh(&dev->tx_lock);
	166	}
	167
	168	/*
	169	* Network device callbacks
	170	*/
	171
4798a2b8 RDC	172	static int gprs_open(struct net_device *dev)
	173	{
	174	struct gprs_dev *gp = netdev_priv(dev);
	175
	176	gprs_write_space(gp->sk);
	177	return 0;
	178	}
	179
	180	static int gprs_close(struct net_device *dev)
	181	{
	182	struct gprs_dev *gp = netdev_priv(dev);
	183
	184	netif_stop_queue(dev);
	185	flush_work(&gp->tx_work);
	186	return 0;
	187	}
	188
02a47617 RDC	189	static int gprs_xmit(struct sk_buff skb, struct net_device net)
	190	{
	191	struct gprs_dev *dev = netdev_priv(net);
	192
	193	switch (skb->protocol) {
	194	case htons(ETH_P_IP):
	195	case htons(ETH_P_IPV6):
	196	break;
	197	default:
	198	dev_kfree_skb(skb);
	199	return 0;
	200	}
	201
	202	spin_lock(&dev->tx_lock);
	203	if (likely(skb_queue_len(&dev->tx_queue) < dev->tx_max)) {
	204	skb_queue_tail(&dev->tx_queue, skb);
	205	skb = NULL;
	206	}
	207	if (skb_queue_len(&dev->tx_queue) >= dev->tx_max)
	208	netif_stop_queue(net);
	209	spin_unlock(&dev->tx_lock);
	210
	211	schedule_work(&dev->tx_work);
	212	if (unlikely(skb))
	213	dev_kfree_skb(skb);
	214	return 0;
	215	}
	216
	217	static void gprs_tx(struct work_struct *work)
	218	{
	219	struct gprs_dev *dev = container_of(work, struct gprs_dev, tx_work);
	220	struct sock *sk = dev->sk;
	221	struct sk_buff *skb;
	222
	223	while ((skb = skb_dequeue(&dev->tx_queue)) != NULL) {
	224	int err;
	225
	226	dev->stats.tx_bytes += skb->len;
	227	dev->stats.tx_packets++;
	228
	229	skb_orphan(skb);
	230	skb_set_owner_w(skb, sk);
	231
	232	lock_sock(sk);
	233	err = pep_write(sk, skb);
	234	if (err) {
	235	LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n",
	236	dev->net->name, err);
	237	dev->stats.tx_aborted_errors++;
	238	dev->stats.tx_errors++;
	239	}
	240	release_sock(sk);
	241	}
	242
	243	lock_sock(sk);
	244	gprs_write_space(sk);
	245	release_sock(sk);
	246	}
	247
	248	static int gprs_set_mtu(struct net_device *net, int new_mtu)
	249	{
	250	if ((new_mtu < 576) \|\| (new_mtu > (PHONET_MAX_MTU - 11)))
	251	return -EINVAL;
	252
253	net->mtu = new_mtu;
254	return 0;
255	}
256
257	static struct net_device_stats gprs_get_stats(struct net_device net)
258	{
259	struct gprs_dev *dev = netdev_priv(net);
260
261	return &dev->stats;
262	}
263
264	static void gprs_setup(struct net_device *net)
265	{
266	net->features = NETIF_F_FRAGLIST;
267	net->type = ARPHRD_NONE;
268	net->flags = IFF_POINTOPOINT \| IFF_NOARP;
269	net->mtu = GPRS_DEFAULT_MTU;
270	net->hard_header_len = 0;
271	net->addr_len = 0;
272	net->tx_queue_len = 10;
273
274	net->destructor = free_netdev;
4798a2b8 RDC	275	net->open = gprs_open;
4798a2b8 RDC	276	net->stop = gprs_close;
02a47617 RDC	277	net->hard_start_xmit = gprs_xmit; /* mandatory */
	278	net->change_mtu = gprs_set_mtu;
	279	net->get_stats = gprs_get_stats;
	280	}
	281
	282	/*
	283	* External interface
	284	*/
	285
	286	/*
	287	* Attach a GPRS interface to a datagram socket.
	288	* Returns the interface index on success, negative error code on error.
	289	*/
	290	int gprs_attach(struct sock *sk)
	291	{
	292	static const char ifname[] = "gprs%d";
	293	struct gprs_dev *dev;
	294	struct net_device *net;
	295	int err;
	296
	297	if (unlikely(sk->sk_type == SOCK_STREAM))
	298	return -EINVAL; /* need packet boundaries */
	299
	300	/* Create net device */
	301	net = alloc_netdev(sizeof(*dev), ifname, gprs_setup);
	302	if (!net)
	303	return -ENOMEM;
	304	dev = netdev_priv(net);
	305	dev->net = net;
	306	dev->tx_max = 0;
	307	spin_lock_init(&dev->tx_lock);
	308	skb_queue_head_init(&dev->tx_queue);
	309	INIT_WORK(&dev->tx_work, gprs_tx);
	310
	311	netif_stop_queue(net);
	312	err = register_netdev(net);
	313	if (err) {
	314	free_netdev(net);
	315	return err;
	316	}
	317
	318	lock_sock(sk);
	319	if (unlikely(sk->sk_user_data)) {
	320	err = -EBUSY;
	321	goto out_rel;
	322	}
	323	if (unlikely((1 << sk->sk_state & (TCPF_CLOSE\|TCPF_LISTEN)) \|\|
	324	sock_flag(sk, SOCK_DEAD))) {
	325	err = -EINVAL;
	326	goto out_rel;
	327	}
	328	sk->sk_user_data = dev;
	329	dev->old_state_change = sk->sk_state_change;
	330	dev->old_data_ready = sk->sk_data_ready;
	331	dev->old_write_space = sk->sk_write_space;
	332	sk->sk_state_change = gprs_state_change;
	333	sk->sk_data_ready = gprs_data_ready;
	334	sk->sk_write_space = gprs_write_space;
	335	release_sock(sk);
	336
	337	sock_hold(sk);
	338	dev->sk = sk;
	339
	340	printk(KERN_DEBUG"%s: attached\n", net->name);
02a47617 RDC	341	return net->ifindex;
	342
	343	out_rel:
	344	release_sock(sk);
	345	unregister_netdev(net);
	346	return err;
	347	}
	348
	349	void gprs_detach(struct sock *sk)
	350	{
	351	struct gprs_dev *dev = sk->sk_user_data;
	352	struct net_device *net = dev->net;
	353
	354	lock_sock(sk);
	355	sk->sk_user_data = NULL;
	356	sk->sk_state_change = dev->old_state_change;
	357	sk->sk_data_ready = dev->old_data_ready;
	358	sk->sk_write_space = dev->old_write_space;
	359	release_sock(sk);
	360
	361	printk(KERN_DEBUG"%s: detached\n", net->name);
	362	unregister_netdev(net);
02a47617	363	sock_put(sk);
02a47617	364	}