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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * File: pep-gprs.c
 *
 * GPRS over Phonet pipe end point socket
 *
 * Copyright (C) 2008 Nokia Corporation.
 *
 * Author: Rémi Denis-Courmont
 */

#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>

#include <trace/events/sock.h>

#define GPRS_DEFAULT_MTU 1400

struct gprs_dev {
	struct sock		*sk;
	void			(*old_state_change)(struct sock *);
	void			(*old_data_ready)(struct sock *);
	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)
{
	struct gprs_dev *gp = sk->sk_user_data;
	struct sk_buff *skb;

	trace_sk_data_ready(sk);

	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) {
		net_dbg_ratelimited("%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 const struct net_device_ops gprs_netdev_ops = {
	.ndo_open	= gprs_open,
	.ndo_stop	= gprs_close,
	.ndo_start_xmit	= gprs_xmit,
};

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->min_mtu		= 576;
	dev->max_mtu		= (PHONET_MAX_MTU - 11);
	dev->hard_header_len	= 0;
	dev->addr_len		= 0;
	dev->tx_queue_len	= 10;

	dev->netdev_ops		= &gprs_netdev_ops;
	dev->needs_free_netdev	= true;
}

/*
 * 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, NET_NAME_UNKNOWN, 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
2b27bdcc	1	// SPDX-License-Identifier: GPL-2.0-only
02a47617 RDC	2	/*
	3	* File: pep-gprs.c
	4	*
	5	* GPRS over Phonet pipe end point socket
	6	*
	7	* Copyright (C) 2008 Nokia Corporation.
	8	*
31fdc555	9	* Author: Rémi Denis-Courmont
02a47617 RDC	10	*/
	11
	12	#include <linux/kernel.h>
	13	#include <linux/netdevice.h>
	14	#include <linux/if_ether.h>
	15	#include <linux/if_arp.h>
	16	#include <net/sock.h>
	17
	18	#include <linux/if_phonet.h>
	19	#include <net/tcp_states.h>
	20	#include <net/phonet/gprs.h>
	21
40e0b090 PY	22	#include <trace/events/sock.h>
40e0b090 PY	23
02a47617 RDC	24	#define GPRS_DEFAULT_MTU 1400
	25
	26	struct gprs_dev {
	27	struct sock *sk;
	28	void (old_state_change)(struct sock );
676d2369	29	void (old_data_ready)(struct sock );
02a47617 RDC	30	void (old_write_space)(struct sock );
02a47617 RDC	31
09a2c3c0	32	struct net_device *dev;
02a47617 RDC	33	};
02a47617 RDC	34
5c7f0333	35	static __be16 gprs_type_trans(struct sk_buff *skb)
02a47617 RDC	36	{
	37	const u8 *pvfc;
	38	u8 buf;
	39
	40	pvfc = skb_header_pointer(skb, 0, 1, &buf);
	41	if (!pvfc)
5c7f0333	42	return htons(0);
02a47617 RDC	43	/* Look at IP version field */
	44	switch (*pvfc >> 4) {
	45	case 4:
	46	return htons(ETH_P_IP);
	47	case 6:
	48	return htons(ETH_P_IPV6);
	49	}
5c7f0333	50	return htons(0);
02a47617 RDC	51	}
02a47617 RDC	52
893873f3 RDC	53	static void gprs_writeable(struct gprs_dev *gp)
	54	{
	55	struct net_device *dev = gp->dev;
	56
	57	if (pep_writeable(gp->sk))
	58	netif_wake_queue(dev);
	59	}
	60
02a47617 RDC	61	/*
	62	* Socket callbacks
	63	*/
	64
	65	static void gprs_state_change(struct sock *sk)
	66	{
09a2c3c0	67	struct gprs_dev *gp = sk->sk_user_data;
02a47617 RDC	68
02a47617 RDC	69	if (sk->sk_state == TCP_CLOSE_WAIT) {
09a2c3c0 RDC	70	struct net_device *dev = gp->dev;
	71
	72	netif_stop_queue(dev);
	73	netif_carrier_off(dev);
02a47617 RDC	74	}
	75	}
	76
09a2c3c0	77	static int gprs_recv(struct gprs_dev gp, struct sk_buff skb)
02a47617	78	{
09a2c3c0	79	struct net_device *dev = gp->dev;
02a47617	80	int err = 0;
5c7f0333	81	__be16 protocol = gprs_type_trans(skb);
02a47617 RDC	82
	83	if (!protocol) {
	84	err = -EINVAL;
	85	goto drop;
	86	}
	87
fc6a1107	88	if (skb_headroom(skb) & 3) {
02a47617 RDC	89	struct sk_buff rskb, fs;
	90	int flen = 0;
	91
fc6a1107	92	/* Phonet Pipe data header may be misaligned (3 bytes),
02a47617 RDC	93	* so wrap the IP packet as a single fragment of an head-less
	94	* socket buffer. The network stack will pull what it needs,
	95	* but at least, the whole IP payload is not memcpy'd. */
09a2c3c0	96	rskb = netdev_alloc_skb(dev, 0);
02a47617 RDC	97	if (!rskb) {
	98	err = -ENOBUFS;
	99	goto drop;
	100	}
	101	skb_shinfo(rskb)->frag_list = skb;
	102	rskb->len += skb->len;
	103	rskb->data_len += rskb->len;
	104	rskb->truesize += rskb->len;
	105
	106	/* Avoid nested fragments */
5c313e9a	107	skb_walk_frags(skb, fs)
02a47617 RDC	108	flen += fs->len;
02a47617 RDC	109	skb->next = skb_shinfo(skb)->frag_list;
5c313e9a	110	skb_frag_list_init(skb);
02a47617 RDC	111	skb->len -= flen;
	112	skb->data_len -= flen;
	113	skb->truesize -= flen;
	114
	115	skb = rskb;
	116	}
	117
	118	skb->protocol = protocol;
	119	skb_reset_mac_header(skb);
09a2c3c0	120	skb->dev = dev;
02a47617	121
09a2c3c0 RDC	122	if (likely(dev->flags & IFF_UP)) {
	123	dev->stats.rx_packets++;
	124	dev->stats.rx_bytes += skb->len;
02a47617 RDC	125	netif_rx(skb);
	126	skb = NULL;
	127	} else
	128	err = -ENODEV;
	129
	130	drop:
	131	if (skb) {
	132	dev_kfree_skb(skb);
09a2c3c0	133	dev->stats.rx_dropped++;
02a47617 RDC	134	}
	135	return err;
	136	}
	137
676d2369	138	static void gprs_data_ready(struct sock *sk)
02a47617	139	{
09a2c3c0	140	struct gprs_dev *gp = sk->sk_user_data;
02a47617 RDC	141	struct sk_buff *skb;
02a47617 RDC	142
40e0b090 PY	143	trace_sk_data_ready(sk);
40e0b090 PY	144
02a47617 RDC	145	while ((skb = pep_read(sk)) != NULL) {
02a47617 RDC	146	skb_orphan(skb);
09a2c3c0	147	gprs_recv(gp, skb);
02a47617 RDC	148	}
	149	}
	150
	151	static void gprs_write_space(struct sock *sk)
	152	{
09a2c3c0	153	struct gprs_dev *gp = sk->sk_user_data;
02a47617	154
893873f3 RDC	155	if (netif_running(gp->dev))
893873f3 RDC	156	gprs_writeable(gp);
02a47617 RDC	157	}
	158
	159	/*
	160	* Network device callbacks
	161	*/
	162
4798a2b8 RDC	163	static int gprs_open(struct net_device *dev)
	164	{
	165	struct gprs_dev *gp = netdev_priv(dev);
	166
893873f3	167	gprs_writeable(gp);
4798a2b8 RDC	168	return 0;
	169	}
	170
	171	static int gprs_close(struct net_device *dev)
	172	{
4798a2b8	173	netif_stop_queue(dev);
4798a2b8 RDC	174	return 0;
	175	}
	176
424efe9c	177	static netdev_tx_t gprs_xmit(struct sk_buff skb, struct net_device dev)
02a47617	178	{
09a2c3c0	179	struct gprs_dev *gp = netdev_priv(dev);
893873f3 RDC	180	struct sock *sk = gp->sk;
893873f3 RDC	181	int len, err;
02a47617 RDC	182
	183	switch (skb->protocol) {
	184	case htons(ETH_P_IP):
	185	case htons(ETH_P_IPV6):
	186	break;
	187	default:
	188	dev_kfree_skb(skb);
6ed10654	189	return NETDEV_TX_OK;
02a47617 RDC	190	}
02a47617 RDC	191
893873f3 RDC	192	skb_orphan(skb);
	193	skb_set_owner_w(skb, sk);
	194	len = skb->len;
	195	err = pep_write(sk, skb);
	196	if (err) {
ba7a46f1	197	net_dbg_ratelimited("%s: TX error (%d)\n", dev->name, err);
893873f3 RDC	198	dev->stats.tx_aborted_errors++;
893873f3 RDC	199	dev->stats.tx_errors++;
893873f3	200	} else {
09a2c3c0	201	dev->stats.tx_packets++;
893873f3	202	dev->stats.tx_bytes += len;
02a47617 RDC	203	}
02a47617 RDC	204
bbd5898d RDC	205	netif_stop_queue(dev);
	206	if (pep_writeable(sk))
	207	netif_wake_queue(dev);
6ed10654	208	return NETDEV_TX_OK;
02a47617 RDC	209	}
02a47617 RDC	210
ab638e69 SH	211	static const struct net_device_ops gprs_netdev_ops = {
	212	.ndo_open = gprs_open,
	213	.ndo_stop = gprs_close,
	214	.ndo_start_xmit = gprs_xmit,
ab638e69 SH	215	};
ab638e69 SH	216
09a2c3c0	217	static void gprs_setup(struct net_device *dev)
02a47617	218	{
09a2c3c0	219	dev->features = NETIF_F_FRAGLIST;
57c81fff	220	dev->type = ARPHRD_PHONET_PIPE;
09a2c3c0 RDC	221	dev->flags = IFF_POINTOPOINT \| IFF_NOARP;
09a2c3c0 RDC	222	dev->mtu = GPRS_DEFAULT_MTU;
b3e3893e JW	223	dev->min_mtu = 576;
b3e3893e JW	224	dev->max_mtu = (PHONET_MAX_MTU - 11);
09a2c3c0 RDC	225	dev->hard_header_len = 0;
	226	dev->addr_len = 0;
	227	dev->tx_queue_len = 10;
	228
ab638e69	229	dev->netdev_ops = &gprs_netdev_ops;
cf124db5	230	dev->needs_free_netdev = true;
02a47617 RDC	231	}
	232
	233	/*
	234	* External interface
	235	*/
	236
	237	/*
	238	* Attach a GPRS interface to a datagram socket.
	239	* Returns the interface index on success, negative error code on error.
	240	*/
	241	int gprs_attach(struct sock *sk)
	242	{
	243	static const char ifname[] = "gprs%d";
09a2c3c0 RDC	244	struct gprs_dev *gp;
09a2c3c0 RDC	245	struct net_device *dev;
02a47617 RDC	246	int err;
	247
	248	if (unlikely(sk->sk_type == SOCK_STREAM))
	249	return -EINVAL; /* need packet boundaries */
	250
	251	/* Create net device */
c835a677	252	dev = alloc_netdev(sizeof(*gp), ifname, NET_NAME_UNKNOWN, gprs_setup);
09a2c3c0	253	if (!dev)
02a47617	254	return -ENOMEM;
09a2c3c0	255	gp = netdev_priv(dev);
893873f3	256	gp->sk = sk;
09a2c3c0	257	gp->dev = dev;
09a2c3c0 RDC	258
	259	netif_stop_queue(dev);
	260	err = register_netdev(dev);
02a47617	261	if (err) {
09a2c3c0	262	free_netdev(dev);
02a47617 RDC	263	return err;
	264	}
	265
	266	lock_sock(sk);
	267	if (unlikely(sk->sk_user_data)) {
	268	err = -EBUSY;
	269	goto out_rel;
	270	}
	271	if (unlikely((1 << sk->sk_state & (TCPF_CLOSE\|TCPF_LISTEN)) \|\|
	272	sock_flag(sk, SOCK_DEAD))) {
	273	err = -EINVAL;
	274	goto out_rel;
	275	}
09a2c3c0 RDC	276	sk->sk_user_data = gp;
	277	gp->old_state_change = sk->sk_state_change;
	278	gp->old_data_ready = sk->sk_data_ready;
	279	gp->old_write_space = sk->sk_write_space;
02a47617 RDC	280	sk->sk_state_change = gprs_state_change;
	281	sk->sk_data_ready = gprs_data_ready;
	282	sk->sk_write_space = gprs_write_space;
	283	release_sock(sk);
02a47617	284	sock_hold(sk);
02a47617	285
09a2c3c0 RDC	286	printk(KERN_DEBUG"%s: attached\n", dev->name);
09a2c3c0 RDC	287	return dev->ifindex;
02a47617 RDC	288
	289	out_rel:
	290	release_sock(sk);
09a2c3c0	291	unregister_netdev(dev);
02a47617 RDC	292	return err;
	293	}
	294
	295	void gprs_detach(struct sock *sk)
	296	{
09a2c3c0 RDC	297	struct gprs_dev *gp = sk->sk_user_data;
09a2c3c0 RDC	298	struct net_device *dev = gp->dev;
02a47617 RDC	299
	300	lock_sock(sk);
	301	sk->sk_user_data = NULL;
09a2c3c0 RDC	302	sk->sk_state_change = gp->old_state_change;
	303	sk->sk_data_ready = gp->old_data_ready;
	304	sk->sk_write_space = gp->old_write_space;
02a47617 RDC	305	release_sock(sk);
02a47617 RDC	306
09a2c3c0 RDC	307	printk(KERN_DEBUG"%s: detached\n", dev->name);
09a2c3c0 RDC	308	unregister_netdev(dev);
02a47617	309	sock_put(sk);
02a47617	310	}