linux/net/l2tp/l2tp_eth.c
Alexander Lobakin 00d066a4d4 netdev_features: convert NETIF_F_LLTX to dev->lltx
NETIF_F_LLTX can't be changed via Ethtool and is not a feature,
rather an attribute, very similar to IFF_NO_QUEUE (and hot).
Free one netdev_features_t bit and make it a "hot" private flag.

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-09-03 11:36:43 +02:00

352 lines
7.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* L2TPv3 ethernet pseudowire driver
*
* Copyright (c) 2008,2009,2010 Katalix Systems Ltd
*/
#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;
};
/* 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 netdev_tx_t 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);
if (likely(ret == NET_XMIT_SUCCESS))
dev_sw_netstats_tx_add(dev, 1, len);
else
DEV_STATS_INC(dev, tx_dropped);
return NETDEV_TX_OK;
}
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 = dev_get_tstats64,
.ndo_set_mac_address = eth_mac_addr,
};
static const 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->lltx = true;
dev->netdev_ops = &l2tp_eth_netdev_ops;
dev->needs_free_netdev = true;
dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
}
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;
if (!pskb_may_pull(skb, ETH_HLEN))
goto error;
secpath_reset(skb);
/* checksums verified by L2TP */
skb->ip_summed = CHECKSUM_NONE;
/* drop outer flow-hash */
skb_clear_hash(skb);
skb_dst_drop(skb);
nf_reset_ct(skb);
rcu_read_lock();
dev = rcu_dereference(spriv->dev);
if (!dev)
goto error_rcu;
if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS)
dev_sw_netstats_rx_add(dev, data_len);
else
DEV_STATS_INC(dev, 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) {
strscpy(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);
refcount_inc(&session->ref_count);
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_put(session);
free_netdev(dev);
return rc;
}
strscpy(session->ifname, dev->name, IFNAMSIZ);
rcu_assign_pointer(spriv->dev, dev);
rtnl_unlock();
l2tp_session_put(session);
__module_get(THIS_MODULE);
return 0;
err_sess_dev:
l2tp_session_put(session);
free_netdev(dev);
err_sess:
l2tp_session_put(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);