diff options
Diffstat (limited to 'net/l2tp/l2tp_eth.c')
-rw-r--r-- | net/l2tp/l2tp_eth.c | 216 |
1 files changed, 133 insertions, 83 deletions
diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c index eecc64e138de..8b8fc2337960 100644 --- a/net/l2tp/l2tp_eth.c +++ b/net/l2tp/l2tp_eth.c @@ -30,6 +30,9 @@ #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" @@ -41,7 +44,6 @@ struct l2tp_eth { struct net_device *dev; struct sock *tunnel_sock; struct l2tp_session *session; - struct list_head list; atomic_long_t tx_bytes; atomic_long_t tx_packets; atomic_long_t tx_dropped; @@ -52,20 +54,9 @@ struct l2tp_eth { /* via l2tp_session_priv() */ struct l2tp_eth_sess { - struct net_device *dev; + struct net_device __rcu *dev; }; -/* per-net private data for this module */ -static unsigned int l2tp_eth_net_id; -struct l2tp_eth_net { - struct list_head l2tp_eth_dev_list; - spinlock_t l2tp_eth_lock; -}; - -static inline struct l2tp_eth_net *l2tp_eth_pernet(struct net *net) -{ - return net_generic(net, l2tp_eth_net_id); -} static int l2tp_eth_dev_init(struct net_device *dev) { @@ -82,12 +73,13 @@ static int l2tp_eth_dev_init(struct net_device *dev) static void l2tp_eth_dev_uninit(struct net_device *dev) { struct l2tp_eth *priv = netdev_priv(dev); - struct l2tp_eth_net *pn = l2tp_eth_pernet(dev_net(dev)); + struct l2tp_eth_sess *spriv; - spin_lock(&pn->l2tp_eth_lock); - list_del_init(&priv->list); - spin_unlock(&pn->l2tp_eth_lock); - dev_put(dev); + 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) @@ -141,8 +133,8 @@ static void l2tp_eth_dev_setup(struct net_device *dev) 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 = spriv->dev; - struct l2tp_eth *priv = netdev_priv(dev); + struct net_device *dev; + struct l2tp_eth *priv; if (session->debug & L2TP_MSG_DATA) { unsigned int length; @@ -166,16 +158,25 @@ static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, 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: - atomic_long_inc(&priv->rx_errors); kfree_skb(skb); } @@ -186,11 +187,15 @@ static void l2tp_eth_delete(struct l2tp_session *session) if (session) { spriv = l2tp_session_priv(session); - dev = spriv->dev; + + rtnl_lock(); + dev = rtnl_dereference(spriv->dev); if (dev) { - unregister_netdev(dev); - spriv->dev = NULL; + unregister_netdevice(dev); + rtnl_unlock(); module_put(THIS_MODULE); + } else { + rtnl_unlock(); } } } @@ -200,35 +205,89 @@ 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 = spriv->dev; + 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); } #endif -static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg) +static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel, + struct l2tp_session *session, + struct net_device *dev) +{ + unsigned int overhead = 0; + struct dst_entry *dst; + u32 l3_overhead = 0; + + /* 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); + } + if (session->mtu != 0) { + dev->mtu = session->mtu; + dev->needed_headroom += session->hdr_len; + return; + } + 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; + + /* If PMTU discovery was enabled, use discovered MTU on L2TP device */ + dst = sk_dst_get(tunnel->sock); + if (dst) { + /* dst_mtu will use PMTU if found, else fallback to intf MTU */ + u32 pmtu = dst_mtu(dst); + + if (pmtu != 0) + dev->mtu = pmtu; + dst_release(dst); + } + session->mtu = dev->mtu - overhead; + dev->mtu = session->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) { struct net_device *dev; char name[IFNAMSIZ]; - struct l2tp_tunnel *tunnel; struct l2tp_session *session; struct l2tp_eth *priv; struct l2tp_eth_sess *spriv; int rc; - struct l2tp_eth_net *pn; - - tunnel = l2tp_tunnel_find(net, tunnel_id); - if (!tunnel) { - rc = -ENODEV; - goto out; - } if (cfg->ifname) { dev = dev_get_by_name(net, cfg->ifname); if (dev) { dev_put(dev); rc = -EEXIST; - goto out; + goto err; } strlcpy(name, cfg->ifname, IFNAMSIZ); } else @@ -238,26 +297,22 @@ static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 p peer_session_id, cfg); if (IS_ERR(session)) { rc = PTR_ERR(session); - goto out; + goto err; } dev = alloc_netdev(sizeof(*priv), name, NET_NAME_UNKNOWN, l2tp_eth_dev_setup); if (!dev) { rc = -ENOMEM; - goto out_del_session; + goto err_sess; } dev_net_set(dev, net); - if (session->mtu == 0) - session->mtu = dev->mtu - session->hdr_len; - dev->mtu = session->mtu; - dev->needed_headroom += session->hdr_len; + l2tp_eth_adjust_mtu(tunnel, session, dev); priv = netdev_priv(dev); priv->dev = dev; priv->session = session; - INIT_LIST_HEAD(&priv->list); priv->tunnel_sock = tunnel->sock; session->recv_skb = l2tp_eth_dev_recv; @@ -267,48 +322,50 @@ static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 p #endif spriv = l2tp_session_priv(session); - spriv->dev = dev; - rc = register_netdev(dev); - if (rc < 0) - goto out_del_dev; + l2tp_session_inc_refcount(session); - __module_get(THIS_MODULE); - /* Must be done after register_netdev() */ - strlcpy(session->ifname, dev->name, IFNAMSIZ); + rtnl_lock(); - dev_hold(dev); - pn = l2tp_eth_pernet(dev_net(dev)); - spin_lock(&pn->l2tp_eth_lock); - list_add(&priv->list, &pn->l2tp_eth_dev_list); - spin_unlock(&pn->l2tp_eth_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; + } - return 0; + rc = register_netdevice(dev); + if (rc < 0) { + rtnl_unlock(); + l2tp_session_delete(session); + l2tp_session_dec_refcount(session); + free_netdev(dev); -out_del_dev: - free_netdev(dev); - spriv->dev = NULL; -out_del_session: - l2tp_session_delete(session); -out: - return rc; -} + return rc; + } -static __net_init int l2tp_eth_init_net(struct net *net) -{ - struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id); + strlcpy(session->ifname, dev->name, IFNAMSIZ); + rcu_assign_pointer(spriv->dev, dev); + + rtnl_unlock(); - INIT_LIST_HEAD(&pn->l2tp_eth_dev_list); - spin_lock_init(&pn->l2tp_eth_lock); + l2tp_session_dec_refcount(session); + + __module_get(THIS_MODULE); return 0; -} -static struct pernet_operations l2tp_eth_net_ops = { - .init = l2tp_eth_init_net, - .id = &l2tp_eth_net_id, - .size = sizeof(struct l2tp_eth_net), -}; +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 = { @@ -323,25 +380,18 @@ static int __init l2tp_eth_init(void) err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops); if (err) - goto out; - - err = register_pernet_device(&l2tp_eth_net_ops); - if (err) - goto out_unreg; + goto err; pr_info("L2TP ethernet pseudowire support (L2TPv3)\n"); return 0; -out_unreg: - l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH); -out: +err: return err; } static void __exit l2tp_eth_exit(void) { - unregister_pernet_device(&l2tp_eth_net_ops); l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH); } |