diff options
Diffstat (limited to 'net/l2tp/l2tp_eth.c')
| -rw-r--r-- | net/l2tp/l2tp_eth.c | 370 |
1 files changed, 370 insertions, 0 deletions
diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c new file mode 100644 index 000000000..f2ae03c40 --- /dev/null +++ b/net/l2tp/l2tp_eth.c @@ -0,0 +1,370 @@ +// 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; + 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 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)) { + 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 (!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_ct(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) { + 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); + + 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; + } + + strscpy(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); |