[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 <[email protected]>
 *
 * 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;
};

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);
}

static void gprs_writeable(struct gprs_dev *gp)
{
	struct net_device *dev = gp->dev;

	if (pep_writeable(gp->sk))
		netif_wake_queue(dev);
}

/*
 * 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 (skb_headroom(skb) & 3) {
		struct sk_buff *rskb, *fs;
		int flen = 0;

		/* Phonet Pipe data header may be 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 */
		skb_walk_frags(skb, fs)
			flen += fs->len;
		skb->next = skb_shinfo(skb)->frag_list;
		skb_frag_list_init(skb);
		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;

	if (netif_running(gp->dev))
		gprs_writeable(gp);
}

/*
 * Network device callbacks
 */

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

	gprs_writeable(gp);
	return 0;
}

static int gprs_close(struct net_device *dev)
{
	netif_stop_queue(dev);
	return 0;
}

static netdev_tx_t gprs_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct gprs_dev *gp = netdev_priv(dev);
	struct sock *sk = gp->sk;
	int len, err;

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

	skb_orphan(skb);
	skb_set_owner_w(skb, sk);
	len = skb->len;
	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++;
	} else {
		dev->stats.tx_packets++;
		dev->stats.tx_bytes += len;
	}

	netif_stop_queue(dev);
	if (pep_writeable(sk))
		netif_wake_queue(dev);
	return NETDEV_TX_OK;
}

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 const struct net_device_ops gprs_netdev_ops = {
	.ndo_open	= gprs_open,
	.ndo_stop	= gprs_close,
	.ndo_start_xmit	= gprs_xmit,
	.ndo_change_mtu	= gprs_set_mtu,
};

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->netdev_ops		= &gprs_netdev_ops;
	dev->destructor		= free_netdev;
}

/*
 * 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->sk = sk;
	gp->dev = dev;

	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);

	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 <[email protected]>
	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	};
02a47617 RDC	45
5c7f0333	46	static __be16 gprs_type_trans(struct sk_buff *skb)
02a47617 RDC	47	{
	48	const u8 *pvfc;
	49	u8 buf;
	50
	51	pvfc = skb_header_pointer(skb, 0, 1, &buf);
	52	if (!pvfc)
5c7f0333	53	return htons(0);
02a47617 RDC	54	/* Look at IP version field */
	55	switch (*pvfc >> 4) {
	56	case 4:
	57	return htons(ETH_P_IP);
	58	case 6:
	59	return htons(ETH_P_IPV6);
	60	}
5c7f0333	61	return htons(0);
02a47617 RDC	62	}
02a47617 RDC	63
893873f3 RDC	64	static void gprs_writeable(struct gprs_dev *gp)
	65	{
	66	struct net_device *dev = gp->dev;
	67
	68	if (pep_writeable(gp->sk))
	69	netif_wake_queue(dev);
	70	}
	71
02a47617 RDC	72	/*
	73	* Socket callbacks
	74	*/
	75
	76	static void gprs_state_change(struct sock *sk)
	77	{
09a2c3c0	78	struct gprs_dev *gp = sk->sk_user_data;
02a47617 RDC	79
02a47617 RDC	80	if (sk->sk_state == TCP_CLOSE_WAIT) {
09a2c3c0 RDC	81	struct net_device *dev = gp->dev;
	82
	83	netif_stop_queue(dev);
	84	netif_carrier_off(dev);
02a47617 RDC	85	}
	86	}
	87
09a2c3c0	88	static int gprs_recv(struct gprs_dev gp, struct sk_buff skb)
02a47617	89	{
09a2c3c0	90	struct net_device *dev = gp->dev;
02a47617	91	int err = 0;
5c7f0333	92	__be16 protocol = gprs_type_trans(skb);
02a47617 RDC	93
	94	if (!protocol) {
	95	err = -EINVAL;
	96	goto drop;
	97	}
	98
fc6a1107	99	if (skb_headroom(skb) & 3) {
02a47617 RDC	100	struct sk_buff rskb, fs;
	101	int flen = 0;
	102
fc6a1107	103	/* Phonet Pipe data header may be misaligned (3 bytes),
02a47617 RDC	104	* so wrap the IP packet as a single fragment of an head-less
	105	* socket buffer. The network stack will pull what it needs,
	106	* but at least, the whole IP payload is not memcpy'd. */
09a2c3c0	107	rskb = netdev_alloc_skb(dev, 0);
02a47617 RDC	108	if (!rskb) {
	109	err = -ENOBUFS;
	110	goto drop;
	111	}
	112	skb_shinfo(rskb)->frag_list = skb;
	113	rskb->len += skb->len;
	114	rskb->data_len += rskb->len;
	115	rskb->truesize += rskb->len;
	116
	117	/* Avoid nested fragments */
5c313e9a	118	skb_walk_frags(skb, fs)
02a47617 RDC	119	flen += fs->len;
02a47617 RDC	120	skb->next = skb_shinfo(skb)->frag_list;
5c313e9a	121	skb_frag_list_init(skb);
02a47617 RDC	122	skb->len -= flen;
	123	skb->data_len -= flen;
	124	skb->truesize -= flen;
	125
	126	skb = rskb;
	127	}
	128
	129	skb->protocol = protocol;
	130	skb_reset_mac_header(skb);
09a2c3c0	131	skb->dev = dev;
02a47617	132
09a2c3c0 RDC	133	if (likely(dev->flags & IFF_UP)) {
	134	dev->stats.rx_packets++;
	135	dev->stats.rx_bytes += skb->len;
02a47617 RDC	136	netif_rx(skb);
	137	skb = NULL;
	138	} else
	139	err = -ENODEV;
	140
	141	drop:
	142	if (skb) {
	143	dev_kfree_skb(skb);
09a2c3c0	144	dev->stats.rx_dropped++;
02a47617 RDC	145	}
	146	return err;
	147	}
	148
	149	static void gprs_data_ready(struct sock *sk, int len)
	150	{
09a2c3c0	151	struct gprs_dev *gp = sk->sk_user_data;
02a47617 RDC	152	struct sk_buff *skb;
	153
	154	while ((skb = pep_read(sk)) != NULL) {
	155	skb_orphan(skb);
09a2c3c0	156	gprs_recv(gp, skb);
02a47617 RDC	157	}
	158	}
	159
	160	static void gprs_write_space(struct sock *sk)
	161	{
09a2c3c0	162	struct gprs_dev *gp = sk->sk_user_data;
02a47617	163
893873f3 RDC	164	if (netif_running(gp->dev))
893873f3 RDC	165	gprs_writeable(gp);
02a47617 RDC	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
893873f3	176	gprs_writeable(gp);
4798a2b8 RDC	177	return 0;
	178	}
	179
	180	static int gprs_close(struct net_device *dev)
	181	{
4798a2b8	182	netif_stop_queue(dev);
4798a2b8 RDC	183	return 0;
	184	}
	185
424efe9c	186	static netdev_tx_t gprs_xmit(struct sk_buff skb, struct net_device dev)
02a47617	187	{
09a2c3c0	188	struct gprs_dev *gp = netdev_priv(dev);
893873f3 RDC	189	struct sock *sk = gp->sk;
893873f3 RDC	190	int len, err;
02a47617 RDC	191
	192	switch (skb->protocol) {
	193	case htons(ETH_P_IP):
	194	case htons(ETH_P_IPV6):
	195	break;
	196	default:
	197	dev_kfree_skb(skb);
6ed10654	198	return NETDEV_TX_OK;
02a47617 RDC	199	}
02a47617 RDC	200
893873f3 RDC	201	skb_orphan(skb);
	202	skb_set_owner_w(skb, sk);
	203	len = skb->len;
	204	err = pep_write(sk, skb);
	205	if (err) {
	206	LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n",
	207	dev->name, err);
	208	dev->stats.tx_aborted_errors++;
	209	dev->stats.tx_errors++;
893873f3	210	} else {
09a2c3c0	211	dev->stats.tx_packets++;
893873f3	212	dev->stats.tx_bytes += len;
02a47617 RDC	213	}
02a47617 RDC	214
bbd5898d RDC	215	netif_stop_queue(dev);
	216	if (pep_writeable(sk))
	217	netif_wake_queue(dev);
6ed10654	218	return NETDEV_TX_OK;
02a47617 RDC	219	}
02a47617 RDC	220
09a2c3c0	221	static int gprs_set_mtu(struct net_device *dev, int new_mtu)
02a47617 RDC	222	{
	223	if ((new_mtu < 576) \|\| (new_mtu > (PHONET_MAX_MTU - 11)))
	224	return -EINVAL;
	225
09a2c3c0	226	dev->mtu = new_mtu;
02a47617 RDC	227	return 0;
	228	}
	229
ab638e69 SH	230	static const struct net_device_ops gprs_netdev_ops = {
	231	.ndo_open = gprs_open,
	232	.ndo_stop = gprs_close,
	233	.ndo_start_xmit = gprs_xmit,
	234	.ndo_change_mtu = gprs_set_mtu,
	235	};
	236
09a2c3c0	237	static void gprs_setup(struct net_device *dev)
02a47617	238	{
09a2c3c0	239	dev->features = NETIF_F_FRAGLIST;
57c81fff	240	dev->type = ARPHRD_PHONET_PIPE;
09a2c3c0 RDC	241	dev->flags = IFF_POINTOPOINT \| IFF_NOARP;
	242	dev->mtu = GPRS_DEFAULT_MTU;
	243	dev->hard_header_len = 0;
	244	dev->addr_len = 0;
	245	dev->tx_queue_len = 10;
	246
ab638e69	247	dev->netdev_ops = &gprs_netdev_ops;
09a2c3c0	248	dev->destructor = free_netdev;
02a47617 RDC	249	}
	250
	251	/*
	252	* External interface
	253	*/
	254
	255	/*
	256	* Attach a GPRS interface to a datagram socket.
	257	* Returns the interface index on success, negative error code on error.
	258	*/
	259	int gprs_attach(struct sock *sk)
	260	{
	261	static const char ifname[] = "gprs%d";
09a2c3c0 RDC	262	struct gprs_dev *gp;
09a2c3c0 RDC	263	struct net_device *dev;
02a47617 RDC	264	int err;
	265
	266	if (unlikely(sk->sk_type == SOCK_STREAM))
	267	return -EINVAL; /* need packet boundaries */
	268
	269	/* Create net device */
09a2c3c0 RDC	270	dev = alloc_netdev(sizeof(*gp), ifname, gprs_setup);
09a2c3c0 RDC	271	if (!dev)
02a47617	272	return -ENOMEM;
09a2c3c0	273	gp = netdev_priv(dev);
893873f3	274	gp->sk = sk;
09a2c3c0	275	gp->dev = dev;
09a2c3c0 RDC	276
	277	netif_stop_queue(dev);
	278	err = register_netdev(dev);
02a47617	279	if (err) {
09a2c3c0	280	free_netdev(dev);
02a47617 RDC	281	return err;
	282	}
	283
	284	lock_sock(sk);
	285	if (unlikely(sk->sk_user_data)) {
	286	err = -EBUSY;
	287	goto out_rel;
	288	}
	289	if (unlikely((1 << sk->sk_state & (TCPF_CLOSE\|TCPF_LISTEN)) \|\|
	290	sock_flag(sk, SOCK_DEAD))) {
	291	err = -EINVAL;
	292	goto out_rel;
	293	}
09a2c3c0 RDC	294	sk->sk_user_data = gp;
	295	gp->old_state_change = sk->sk_state_change;
	296	gp->old_data_ready = sk->sk_data_ready;
	297	gp->old_write_space = sk->sk_write_space;
02a47617 RDC	298	sk->sk_state_change = gprs_state_change;
	299	sk->sk_data_ready = gprs_data_ready;
	300	sk->sk_write_space = gprs_write_space;
	301	release_sock(sk);
02a47617	302	sock_hold(sk);
02a47617	303
09a2c3c0 RDC	304	printk(KERN_DEBUG"%s: attached\n", dev->name);
09a2c3c0 RDC	305	return dev->ifindex;
02a47617 RDC	306
	307	out_rel:
	308	release_sock(sk);
09a2c3c0	309	unregister_netdev(dev);
02a47617 RDC	310	return err;
	311	}
	312
	313	void gprs_detach(struct sock *sk)
	314	{
09a2c3c0 RDC	315	struct gprs_dev *gp = sk->sk_user_data;
09a2c3c0 RDC	316	struct net_device *dev = gp->dev;
02a47617 RDC	317
	318	lock_sock(sk);
	319	sk->sk_user_data = NULL;
09a2c3c0 RDC	320	sk->sk_state_change = gp->old_state_change;
	321	sk->sk_data_ready = gp->old_data_ready;
	322	sk->sk_write_space = gp->old_write_space;
02a47617 RDC	323	release_sock(sk);
02a47617 RDC	324
09a2c3c0 RDC	325	printk(KERN_DEBUG"%s: detached\n", dev->name);
09a2c3c0 RDC	326	unregister_netdev(dev);
02a47617	327	sock_put(sk);
02a47617	328	}