3953ae7b21
Sessions created by l2tp_session_create() aren't fully initialised: some pseudo-wire specific operations need to be done before making the session usable. Therefore the PPP and Ethernet pseudo-wires continue working on the returned l2tp session while it's already been exposed to the rest of the system. This can lead to various issues. In particular, the session may enter the deletion process before having been fully initialised, which will confuse the session removal code. This patch moves session registration out of l2tp_session_create(), so that callers can control when the session is exposed to the rest of the system. This is done by the new l2tp_session_register() function. Only pppol2tp_session_create() can be easily converted to avoid modifying its session after registration (the debug message is dropped in order to avoid the need for holding a reference on the session). For pppol2tp_connect() and l2tp_eth_create()), more work is needed. That'll be done in followup patches. For now, let's just register the session right after its creation, like it was done before. The only difference is that we can easily take a reference on the session before registering it, so, at least, we're sure it's not going to be freed while we're working on it. Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
366 lines
8.6 KiB
C
366 lines
8.6 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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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 net_device *dev;
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struct sock *tunnel_sock;
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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 *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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struct l2tp_eth *priv = netdev_priv(dev);
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priv->dev = dev;
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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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dev_put(dev);
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}
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static int 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, session->hdr_len);
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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 = spriv->dev;
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struct l2tp_eth *priv = netdev_priv(dev);
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if (session->debug & L2TP_MSG_DATA) {
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unsigned int length;
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length = min(32u, skb->len);
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if (!pskb_may_pull(skb, length))
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goto error;
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pr_debug("%s: eth recv\n", session->name);
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print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
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}
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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(skb);
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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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return;
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error:
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atomic_long_inc(&priv->rx_errors);
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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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dev = spriv->dev;
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if (dev) {
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unregister_netdev(dev);
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spriv->dev = NULL;
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module_put(THIS_MODULE);
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}
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}
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}
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#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
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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 = spriv->dev;
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seq_printf(m, " interface %s\n", dev->name);
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}
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#endif
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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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struct dst_entry *dst;
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u32 l3_overhead = 0;
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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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if (session->mtu != 0) {
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dev->mtu = session->mtu;
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dev->needed_headroom += session->hdr_len;
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return;
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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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/* If PMTU discovery was enabled, use discovered MTU on L2TP device */
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dst = sk_dst_get(tunnel->sock);
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if (dst) {
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/* dst_mtu will use PMTU if found, else fallback to intf MTU */
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u32 pmtu = dst_mtu(dst);
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if (pmtu != 0)
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dev->mtu = pmtu;
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dst_release(dst);
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}
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session->mtu = dev->mtu - overhead;
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dev->mtu = session->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 out;
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}
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l2tp_session_inc_refcount(session);
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rc = l2tp_session_register(session, tunnel);
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if (rc < 0) {
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kfree(session);
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goto out;
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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 out_del_session;
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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->dev = dev;
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priv->session = session;
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priv->tunnel_sock = tunnel->sock;
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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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#endif
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spriv = l2tp_session_priv(session);
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spriv->dev = dev;
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rc = register_netdev(dev);
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if (rc < 0)
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goto out_del_dev;
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__module_get(THIS_MODULE);
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/* Must be done after register_netdev() */
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strlcpy(session->ifname, dev->name, IFNAMSIZ);
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l2tp_session_dec_refcount(session);
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dev_hold(dev);
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return 0;
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out_del_dev:
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free_netdev(dev);
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spriv->dev = NULL;
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out_del_session:
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l2tp_session_delete(session);
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l2tp_session_dec_refcount(session);
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out:
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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 <jchapman@katalix.com>");
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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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