/*
 * File: pep-gprs.c
 *
 * GPRS over Phonet pipe end point socket
 *
 * Copyright (C) 2008 Nokia Corporation.
 *
 * Author: Rémi Denis-Courmont
 *
 * 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 *);
	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;

	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->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, 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);
}
><td><span title='2017-02-10 11:32:12 -0500'>2017-02-10</span></td><td class='logsubject'><a href='/cgit.cgi/linux/net-next.git/commit/net/ipv4/fib_trie.c?id=58e3bdd59742feef680861acec19126e40e4fa8d'>ipv4: fib: Only flush FIB aliases belonging to currently flushed table</a></td><td>Ido Schimmel</td><td>1</td><td><span class='deletions'>-1</span>/<span class='insertions'>+2</span></td></tr>
<tr class='nohover-highlight'><td/><td colspan='5' class='logmsg'>
In case the MAIN table is flushed and its trie is shared with the LOCAL
table, then we might be flushing FIB aliases belonging to the latter.
This can lead to FIB_ENTRY_DEL notifications sent with the wrong table
ID.

The above doesn't affect current listeners, as the table ID is ignored
during entry deletion, but this will change later in the patchset.

When flushing a particular table, skip any aliases belonging to a
different one.

Signed-off-by: Ido Schimmel &lt;idosch@mellanox.com&gt;
Signed-off-by: Jiri Pirko &lt;jiri@mellanox.com&gt;
CC: Alexander Duyck &lt;alexander.h.duyck@intel.com&gt;
CC: Patrick McHardy &lt;kaber@trash.net&gt;
Reviewed-by: Alexander Duyck &lt;alexander.h.duyck@intel.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;


</td></tr>