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370 lines
8.4 KiB
370 lines
8.4 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* L2TPv3 ethernet pseudowire driver |
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* |
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* Copyright (c) 2008,2009,2010 Katalix Systems Ltd |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> |
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#include <linux/skbuff.h> |
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#include <linux/socket.h> |
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#include <linux/hash.h> |
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#include <linux/l2tp.h> |
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#include <linux/in.h> |
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#include <linux/etherdevice.h> |
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#include <linux/spinlock.h> |
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#include <net/sock.h> |
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#include <net/ip.h> |
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#include <net/icmp.h> |
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#include <net/udp.h> |
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#include <net/inet_common.h> |
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#include <net/inet_hashtables.h> |
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#include <net/tcp_states.h> |
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#include <net/protocol.h> |
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#include <net/xfrm.h> |
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#include <net/net_namespace.h> |
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#include <net/netns/generic.h> |
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#include <linux/ip.h> |
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#include <linux/ipv6.h> |
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#include <linux/udp.h> |
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#include "l2tp_core.h" |
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/* Default device name. May be overridden by name specified by user */ |
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#define L2TP_ETH_DEV_NAME "l2tpeth%d" |
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/* via netdev_priv() */ |
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struct l2tp_eth { |
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struct l2tp_session *session; |
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atomic_long_t tx_bytes; |
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atomic_long_t tx_packets; |
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atomic_long_t tx_dropped; |
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atomic_long_t rx_bytes; |
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atomic_long_t rx_packets; |
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atomic_long_t rx_errors; |
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}; |
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/* via l2tp_session_priv() */ |
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struct l2tp_eth_sess { |
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struct net_device __rcu *dev; |
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}; |
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static int l2tp_eth_dev_init(struct net_device *dev) |
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{ |
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eth_hw_addr_random(dev); |
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eth_broadcast_addr(dev->broadcast); |
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netdev_lockdep_set_classes(dev); |
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return 0; |
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} |
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static void l2tp_eth_dev_uninit(struct net_device *dev) |
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{ |
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struct l2tp_eth *priv = netdev_priv(dev); |
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struct l2tp_eth_sess *spriv; |
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spriv = l2tp_session_priv(priv->session); |
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RCU_INIT_POINTER(spriv->dev, NULL); |
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/* No need for synchronize_net() here. We're called by |
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* unregister_netdev*(), which does the synchronisation for us. |
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*/ |
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} |
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static netdev_tx_t l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev) |
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{ |
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struct l2tp_eth *priv = netdev_priv(dev); |
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struct l2tp_session *session = priv->session; |
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unsigned int len = skb->len; |
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int ret = l2tp_xmit_skb(session, skb); |
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if (likely(ret == NET_XMIT_SUCCESS)) { |
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atomic_long_add(len, &priv->tx_bytes); |
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atomic_long_inc(&priv->tx_packets); |
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} else { |
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atomic_long_inc(&priv->tx_dropped); |
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} |
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return NETDEV_TX_OK; |
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} |
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static void l2tp_eth_get_stats64(struct net_device *dev, |
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struct rtnl_link_stats64 *stats) |
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{ |
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struct l2tp_eth *priv = netdev_priv(dev); |
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stats->tx_bytes = (unsigned long)atomic_long_read(&priv->tx_bytes); |
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stats->tx_packets = (unsigned long)atomic_long_read(&priv->tx_packets); |
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stats->tx_dropped = (unsigned long)atomic_long_read(&priv->tx_dropped); |
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stats->rx_bytes = (unsigned long)atomic_long_read(&priv->rx_bytes); |
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stats->rx_packets = (unsigned long)atomic_long_read(&priv->rx_packets); |
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stats->rx_errors = (unsigned long)atomic_long_read(&priv->rx_errors); |
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} |
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static const struct net_device_ops l2tp_eth_netdev_ops = { |
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.ndo_init = l2tp_eth_dev_init, |
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.ndo_uninit = l2tp_eth_dev_uninit, |
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.ndo_start_xmit = l2tp_eth_dev_xmit, |
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.ndo_get_stats64 = l2tp_eth_get_stats64, |
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.ndo_set_mac_address = eth_mac_addr, |
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}; |
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static struct device_type l2tpeth_type = { |
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.name = "l2tpeth", |
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}; |
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static void l2tp_eth_dev_setup(struct net_device *dev) |
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{ |
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SET_NETDEV_DEVTYPE(dev, &l2tpeth_type); |
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ether_setup(dev); |
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dev->priv_flags &= ~IFF_TX_SKB_SHARING; |
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dev->features |= NETIF_F_LLTX; |
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dev->netdev_ops = &l2tp_eth_netdev_ops; |
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dev->needs_free_netdev = true; |
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} |
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static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len) |
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{ |
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struct l2tp_eth_sess *spriv = l2tp_session_priv(session); |
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struct net_device *dev; |
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struct l2tp_eth *priv; |
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if (!pskb_may_pull(skb, ETH_HLEN)) |
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goto error; |
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secpath_reset(skb); |
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/* checksums verified by L2TP */ |
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skb->ip_summed = CHECKSUM_NONE; |
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skb_dst_drop(skb); |
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nf_reset_ct(skb); |
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rcu_read_lock(); |
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dev = rcu_dereference(spriv->dev); |
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if (!dev) |
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goto error_rcu; |
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priv = netdev_priv(dev); |
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if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) { |
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atomic_long_inc(&priv->rx_packets); |
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atomic_long_add(data_len, &priv->rx_bytes); |
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} else { |
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atomic_long_inc(&priv->rx_errors); |
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} |
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rcu_read_unlock(); |
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return; |
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error_rcu: |
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rcu_read_unlock(); |
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error: |
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kfree_skb(skb); |
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} |
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static void l2tp_eth_delete(struct l2tp_session *session) |
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{ |
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struct l2tp_eth_sess *spriv; |
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struct net_device *dev; |
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if (session) { |
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spriv = l2tp_session_priv(session); |
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rtnl_lock(); |
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dev = rtnl_dereference(spriv->dev); |
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if (dev) { |
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unregister_netdevice(dev); |
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rtnl_unlock(); |
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module_put(THIS_MODULE); |
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} else { |
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rtnl_unlock(); |
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} |
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} |
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} |
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static void l2tp_eth_show(struct seq_file *m, void *arg) |
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{ |
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struct l2tp_session *session = arg; |
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struct l2tp_eth_sess *spriv = l2tp_session_priv(session); |
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struct net_device *dev; |
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rcu_read_lock(); |
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dev = rcu_dereference(spriv->dev); |
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if (!dev) { |
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rcu_read_unlock(); |
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return; |
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} |
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dev_hold(dev); |
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rcu_read_unlock(); |
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seq_printf(m, " interface %s\n", dev->name); |
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dev_put(dev); |
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} |
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static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel, |
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struct l2tp_session *session, |
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struct net_device *dev) |
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{ |
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unsigned int overhead = 0; |
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u32 l3_overhead = 0; |
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u32 mtu; |
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/* if the encap is UDP, account for UDP header size */ |
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if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { |
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overhead += sizeof(struct udphdr); |
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dev->needed_headroom += sizeof(struct udphdr); |
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} |
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lock_sock(tunnel->sock); |
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l3_overhead = kernel_sock_ip_overhead(tunnel->sock); |
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release_sock(tunnel->sock); |
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if (l3_overhead == 0) { |
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/* L3 Overhead couldn't be identified, this could be |
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* because tunnel->sock was NULL or the socket's |
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* address family was not IPv4 or IPv6, |
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* dev mtu stays at 1500. |
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*/ |
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return; |
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} |
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/* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr |
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* UDP overhead, if any, was already factored in above. |
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*/ |
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overhead += session->hdr_len + ETH_HLEN + l3_overhead; |
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mtu = l2tp_tunnel_dst_mtu(tunnel) - overhead; |
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if (mtu < dev->min_mtu || mtu > dev->max_mtu) |
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dev->mtu = ETH_DATA_LEN - overhead; |
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else |
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dev->mtu = mtu; |
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dev->needed_headroom += session->hdr_len; |
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} |
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static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel, |
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u32 session_id, u32 peer_session_id, |
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struct l2tp_session_cfg *cfg) |
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{ |
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unsigned char name_assign_type; |
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struct net_device *dev; |
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char name[IFNAMSIZ]; |
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struct l2tp_session *session; |
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struct l2tp_eth *priv; |
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struct l2tp_eth_sess *spriv; |
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int rc; |
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if (cfg->ifname) { |
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strlcpy(name, cfg->ifname, IFNAMSIZ); |
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name_assign_type = NET_NAME_USER; |
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} else { |
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strcpy(name, L2TP_ETH_DEV_NAME); |
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name_assign_type = NET_NAME_ENUM; |
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} |
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session = l2tp_session_create(sizeof(*spriv), tunnel, session_id, |
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peer_session_id, cfg); |
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if (IS_ERR(session)) { |
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rc = PTR_ERR(session); |
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goto err; |
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} |
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dev = alloc_netdev(sizeof(*priv), name, name_assign_type, |
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l2tp_eth_dev_setup); |
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if (!dev) { |
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rc = -ENOMEM; |
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goto err_sess; |
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} |
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dev_net_set(dev, net); |
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dev->min_mtu = 0; |
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dev->max_mtu = ETH_MAX_MTU; |
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l2tp_eth_adjust_mtu(tunnel, session, dev); |
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priv = netdev_priv(dev); |
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priv->session = session; |
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session->recv_skb = l2tp_eth_dev_recv; |
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session->session_close = l2tp_eth_delete; |
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if (IS_ENABLED(CONFIG_L2TP_DEBUGFS)) |
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session->show = l2tp_eth_show; |
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spriv = l2tp_session_priv(session); |
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l2tp_session_inc_refcount(session); |
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rtnl_lock(); |
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/* Register both device and session while holding the rtnl lock. This |
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* ensures that l2tp_eth_delete() will see that there's a device to |
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* unregister, even if it happened to run before we assign spriv->dev. |
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*/ |
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rc = l2tp_session_register(session, tunnel); |
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if (rc < 0) { |
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rtnl_unlock(); |
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goto err_sess_dev; |
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} |
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rc = register_netdevice(dev); |
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if (rc < 0) { |
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rtnl_unlock(); |
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l2tp_session_delete(session); |
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l2tp_session_dec_refcount(session); |
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free_netdev(dev); |
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return rc; |
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} |
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strlcpy(session->ifname, dev->name, IFNAMSIZ); |
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rcu_assign_pointer(spriv->dev, dev); |
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rtnl_unlock(); |
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l2tp_session_dec_refcount(session); |
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__module_get(THIS_MODULE); |
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return 0; |
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err_sess_dev: |
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l2tp_session_dec_refcount(session); |
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free_netdev(dev); |
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err_sess: |
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kfree(session); |
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err: |
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return rc; |
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} |
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static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = { |
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.session_create = l2tp_eth_create, |
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.session_delete = l2tp_session_delete, |
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}; |
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static int __init l2tp_eth_init(void) |
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{ |
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int err = 0; |
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err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops); |
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if (err) |
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goto err; |
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pr_info("L2TP ethernet pseudowire support (L2TPv3)\n"); |
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return 0; |
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err: |
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return err; |
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} |
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static void __exit l2tp_eth_exit(void) |
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{ |
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l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH); |
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} |
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module_init(l2tp_eth_init); |
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module_exit(l2tp_eth_exit); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("James Chapman <[email protected]>"); |
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MODULE_DESCRIPTION("L2TP ethernet pseudowire driver"); |
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MODULE_VERSION("1.0"); |
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MODULE_ALIAS_L2TP_PWTYPE(5);
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