linux/net/l2tp/l2tp_eth.c
Arnd Bergmann c2ebc25674 l2tp: fix unused function warning
Removing one of the callers of pppol2tp_session_get_sock caused a harmless
warning in some configurations:

net/l2tp/l2tp_ppp.c:142:21: 'pppol2tp_session_get_sock' defined but not used [-Wunused-function]

Rather than adding another #ifdef here, using a proper IS_ENABLED()
check makes the code more readable and avoids those warnings while
letting the compiler figure out for itself which code is needed.

This adds one pointer for the unused show() callback in struct
l2tp_session, but that seems harmless.

Fixes: b0e29063dc ("l2tp: remove pppol2tp_session_ioctl()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-13 20:45:49 -07:00

391 lines
8.9 KiB
C

/*
* L2TPv3 ethernet pseudowire driver
*
* Copyright (c) 2008,2009,2010 Katalix Systems Ltd
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/hash.h>
#include <linux/l2tp.h>
#include <linux/in.h>
#include <linux/etherdevice.h>
#include <linux/spinlock.h>
#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/inet_common.h>
#include <net/inet_hashtables.h>
#include <net/tcp_states.h>
#include <net/protocol.h>
#include <net/xfrm.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/udp.h>
#include "l2tp_core.h"
/* Default device name. May be overridden by name specified by user */
#define L2TP_ETH_DEV_NAME "l2tpeth%d"
/* via netdev_priv() */
struct l2tp_eth {
struct l2tp_session *session;
atomic_long_t tx_bytes;
atomic_long_t tx_packets;
atomic_long_t tx_dropped;
atomic_long_t rx_bytes;
atomic_long_t rx_packets;
atomic_long_t rx_errors;
};
/* via l2tp_session_priv() */
struct l2tp_eth_sess {
struct net_device __rcu *dev;
};
static int l2tp_eth_dev_init(struct net_device *dev)
{
eth_hw_addr_random(dev);
eth_broadcast_addr(dev->broadcast);
netdev_lockdep_set_classes(dev);
return 0;
}
static void l2tp_eth_dev_uninit(struct net_device *dev)
{
struct l2tp_eth *priv = netdev_priv(dev);
struct l2tp_eth_sess *spriv;
spriv = l2tp_session_priv(priv->session);
RCU_INIT_POINTER(spriv->dev, NULL);
/* No need for synchronize_net() here. We're called by
* unregister_netdev*(), which does the synchronisation for us.
*/
}
static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct l2tp_eth *priv = netdev_priv(dev);
struct l2tp_session *session = priv->session;
unsigned int len = skb->len;
int ret = l2tp_xmit_skb(session, skb, session->hdr_len);
if (likely(ret == NET_XMIT_SUCCESS)) {
atomic_long_add(len, &priv->tx_bytes);
atomic_long_inc(&priv->tx_packets);
} else {
atomic_long_inc(&priv->tx_dropped);
}
return NETDEV_TX_OK;
}
static void l2tp_eth_get_stats64(struct net_device *dev,
struct rtnl_link_stats64 *stats)
{
struct l2tp_eth *priv = netdev_priv(dev);
stats->tx_bytes = (unsigned long) atomic_long_read(&priv->tx_bytes);
stats->tx_packets = (unsigned long) atomic_long_read(&priv->tx_packets);
stats->tx_dropped = (unsigned long) atomic_long_read(&priv->tx_dropped);
stats->rx_bytes = (unsigned long) atomic_long_read(&priv->rx_bytes);
stats->rx_packets = (unsigned long) atomic_long_read(&priv->rx_packets);
stats->rx_errors = (unsigned long) atomic_long_read(&priv->rx_errors);
}
static const struct net_device_ops l2tp_eth_netdev_ops = {
.ndo_init = l2tp_eth_dev_init,
.ndo_uninit = l2tp_eth_dev_uninit,
.ndo_start_xmit = l2tp_eth_dev_xmit,
.ndo_get_stats64 = l2tp_eth_get_stats64,
.ndo_set_mac_address = eth_mac_addr,
};
static struct device_type l2tpeth_type = {
.name = "l2tpeth",
};
static void l2tp_eth_dev_setup(struct net_device *dev)
{
SET_NETDEV_DEVTYPE(dev, &l2tpeth_type);
ether_setup(dev);
dev->priv_flags &= ~IFF_TX_SKB_SHARING;
dev->features |= NETIF_F_LLTX;
dev->netdev_ops = &l2tp_eth_netdev_ops;
dev->needs_free_netdev = true;
}
static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
{
struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
struct net_device *dev;
struct l2tp_eth *priv;
if (session->debug & L2TP_MSG_DATA) {
unsigned int length;
length = min(32u, skb->len);
if (!pskb_may_pull(skb, length))
goto error;
pr_debug("%s: eth recv\n", session->name);
print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
}
if (!pskb_may_pull(skb, ETH_HLEN))
goto error;
secpath_reset(skb);
/* checksums verified by L2TP */
skb->ip_summed = CHECKSUM_NONE;
skb_dst_drop(skb);
nf_reset(skb);
rcu_read_lock();
dev = rcu_dereference(spriv->dev);
if (!dev)
goto error_rcu;
priv = netdev_priv(dev);
if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
atomic_long_inc(&priv->rx_packets);
atomic_long_add(data_len, &priv->rx_bytes);
} else {
atomic_long_inc(&priv->rx_errors);
}
rcu_read_unlock();
return;
error_rcu:
rcu_read_unlock();
error:
kfree_skb(skb);
}
static void l2tp_eth_delete(struct l2tp_session *session)
{
struct l2tp_eth_sess *spriv;
struct net_device *dev;
if (session) {
spriv = l2tp_session_priv(session);
rtnl_lock();
dev = rtnl_dereference(spriv->dev);
if (dev) {
unregister_netdevice(dev);
rtnl_unlock();
module_put(THIS_MODULE);
} else {
rtnl_unlock();
}
}
}
static void l2tp_eth_show(struct seq_file *m, void *arg)
{
struct l2tp_session *session = arg;
struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
struct net_device *dev;
rcu_read_lock();
dev = rcu_dereference(spriv->dev);
if (!dev) {
rcu_read_unlock();
return;
}
dev_hold(dev);
rcu_read_unlock();
seq_printf(m, " interface %s\n", dev->name);
dev_put(dev);
}
static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
struct l2tp_session *session,
struct net_device *dev)
{
unsigned int overhead = 0;
u32 l3_overhead = 0;
u32 mtu;
/* if the encap is UDP, account for UDP header size */
if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
overhead += sizeof(struct udphdr);
dev->needed_headroom += sizeof(struct udphdr);
}
lock_sock(tunnel->sock);
l3_overhead = kernel_sock_ip_overhead(tunnel->sock);
release_sock(tunnel->sock);
if (l3_overhead == 0) {
/* L3 Overhead couldn't be identified, this could be
* because tunnel->sock was NULL or the socket's
* address family was not IPv4 or IPv6,
* dev mtu stays at 1500.
*/
return;
}
/* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr
* UDP overhead, if any, was already factored in above.
*/
overhead += session->hdr_len + ETH_HLEN + l3_overhead;
mtu = l2tp_tunnel_dst_mtu(tunnel) - overhead;
if (mtu < dev->min_mtu || mtu > dev->max_mtu)
dev->mtu = ETH_DATA_LEN - overhead;
else
dev->mtu = mtu;
dev->needed_headroom += session->hdr_len;
}
static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
u32 session_id, u32 peer_session_id,
struct l2tp_session_cfg *cfg)
{
unsigned char name_assign_type;
struct net_device *dev;
char name[IFNAMSIZ];
struct l2tp_session *session;
struct l2tp_eth *priv;
struct l2tp_eth_sess *spriv;
int rc;
if (cfg->ifname) {
strlcpy(name, cfg->ifname, IFNAMSIZ);
name_assign_type = NET_NAME_USER;
} else {
strcpy(name, L2TP_ETH_DEV_NAME);
name_assign_type = NET_NAME_ENUM;
}
session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
peer_session_id, cfg);
if (IS_ERR(session)) {
rc = PTR_ERR(session);
goto err;
}
dev = alloc_netdev(sizeof(*priv), name, name_assign_type,
l2tp_eth_dev_setup);
if (!dev) {
rc = -ENOMEM;
goto err_sess;
}
dev_net_set(dev, net);
dev->min_mtu = 0;
dev->max_mtu = ETH_MAX_MTU;
l2tp_eth_adjust_mtu(tunnel, session, dev);
priv = netdev_priv(dev);
priv->session = session;
session->recv_skb = l2tp_eth_dev_recv;
session->session_close = l2tp_eth_delete;
if (IS_ENABLED(CONFIG_L2TP_DEBUGFS))
session->show = l2tp_eth_show;
spriv = l2tp_session_priv(session);
l2tp_session_inc_refcount(session);
rtnl_lock();
/* Register both device and session while holding the rtnl lock. This
* ensures that l2tp_eth_delete() will see that there's a device to
* unregister, even if it happened to run before we assign spriv->dev.
*/
rc = l2tp_session_register(session, tunnel);
if (rc < 0) {
rtnl_unlock();
goto err_sess_dev;
}
rc = register_netdevice(dev);
if (rc < 0) {
rtnl_unlock();
l2tp_session_delete(session);
l2tp_session_dec_refcount(session);
free_netdev(dev);
return rc;
}
strlcpy(session->ifname, dev->name, IFNAMSIZ);
rcu_assign_pointer(spriv->dev, dev);
rtnl_unlock();
l2tp_session_dec_refcount(session);
__module_get(THIS_MODULE);
return 0;
err_sess_dev:
l2tp_session_dec_refcount(session);
free_netdev(dev);
err_sess:
kfree(session);
err:
return rc;
}
static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
.session_create = l2tp_eth_create,
.session_delete = l2tp_session_delete,
};
static int __init l2tp_eth_init(void)
{
int err = 0;
err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
if (err)
goto err;
pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
return 0;
err:
return err;
}
static void __exit l2tp_eth_exit(void)
{
l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
}
module_init(l2tp_eth_init);
module_exit(l2tp_eth_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
MODULE_VERSION("1.0");
MODULE_ALIAS_L2TP_PWTYPE(5);