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![Eric Dumazet](/assets/img/avatar_default.png)
lockdep complains with the following lock/unlock sequence:
lock_sock(sk);
write_lock_bh(&sk->sk_callback_lock);
[1] release_sock(sk);
[2] write_unlock_bh(&sk->sk_callback_lock);
We need to swap [1] and [2] to fix this issue.
Fixes: 0b2c59720e
("l2tp: close all race conditions in l2tp_tunnel_register()")
Reported-by: syzbot+bbd35b345c7cab0d9a08@syzkaller.appspotmail.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/netdev/20230114030137.672706-1-xiyou.wangcong@gmail.com/T/#m1164ff20628671b0f326a24cb106ab3239c70ce3
Cc: Cong Wang <cong.wang@bytedance.com>
Cc: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1723 lines
45 KiB
C
1723 lines
45 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* L2TP core.
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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 file contains some code of the original L2TPv2 pppol2tp
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* driver, which has the following copyright:
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*
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* Authors: Martijn van Oosterhout <kleptog@svana.org>
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* James Chapman (jchapman@katalix.com)
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* Contributors:
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* Michal Ostrowski <mostrows@speakeasy.net>
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* Arnaldo Carvalho de Melo <acme@xconectiva.com.br>
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* David S. Miller (davem@redhat.com)
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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/string.h>
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#include <linux/list.h>
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#include <linux/rculist.h>
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#include <linux/uaccess.h>
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#include <linux/kernel.h>
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#include <linux/spinlock.h>
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#include <linux/kthread.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/jiffies.h>
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#include <linux/netdevice.h>
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#include <linux/net.h>
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#include <linux/inetdevice.h>
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#include <linux/skbuff.h>
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#include <linux/init.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/udp.h>
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#include <linux/l2tp.h>
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#include <linux/hash.h>
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#include <linux/sort.h>
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#include <linux/file.h>
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#include <linux/nsproxy.h>
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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#include <net/dst.h>
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#include <net/ip.h>
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#include <net/udp.h>
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#include <net/udp_tunnel.h>
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#include <net/inet_common.h>
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#include <net/xfrm.h>
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#include <net/protocol.h>
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#include <net/inet6_connection_sock.h>
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#include <net/inet_ecn.h>
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#include <net/ip6_route.h>
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#include <net/ip6_checksum.h>
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#include <asm/byteorder.h>
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#include <linux/atomic.h>
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#include "l2tp_core.h"
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#include "trace.h"
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#define CREATE_TRACE_POINTS
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#include "trace.h"
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#define L2TP_DRV_VERSION "V2.0"
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/* L2TP header constants */
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#define L2TP_HDRFLAG_T 0x8000
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#define L2TP_HDRFLAG_L 0x4000
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#define L2TP_HDRFLAG_S 0x0800
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#define L2TP_HDRFLAG_O 0x0200
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#define L2TP_HDRFLAG_P 0x0100
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#define L2TP_HDR_VER_MASK 0x000F
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#define L2TP_HDR_VER_2 0x0002
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#define L2TP_HDR_VER_3 0x0003
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/* L2TPv3 default L2-specific sublayer */
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#define L2TP_SLFLAG_S 0x40000000
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#define L2TP_SL_SEQ_MASK 0x00ffffff
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#define L2TP_HDR_SIZE_MAX 14
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/* Default trace flags */
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#define L2TP_DEFAULT_DEBUG_FLAGS 0
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/* Private data stored for received packets in the skb.
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*/
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struct l2tp_skb_cb {
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u32 ns;
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u16 has_seq;
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u16 length;
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unsigned long expires;
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};
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#define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *)&(skb)->cb[sizeof(struct inet_skb_parm)])
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static struct workqueue_struct *l2tp_wq;
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/* per-net private data for this module */
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static unsigned int l2tp_net_id;
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struct l2tp_net {
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/* Lock for write access to l2tp_tunnel_idr */
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spinlock_t l2tp_tunnel_idr_lock;
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struct idr l2tp_tunnel_idr;
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struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
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/* Lock for write access to l2tp_session_hlist */
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spinlock_t l2tp_session_hlist_lock;
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};
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#if IS_ENABLED(CONFIG_IPV6)
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static bool l2tp_sk_is_v6(struct sock *sk)
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{
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return sk->sk_family == PF_INET6 &&
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!ipv6_addr_v4mapped(&sk->sk_v6_daddr);
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}
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#endif
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static inline struct l2tp_net *l2tp_pernet(const struct net *net)
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{
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return net_generic(net, l2tp_net_id);
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}
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/* Session hash global list for L2TPv3.
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* The session_id SHOULD be random according to RFC3931, but several
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* L2TP implementations use incrementing session_ids. So we do a real
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* hash on the session_id, rather than a simple bitmask.
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*/
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static inline struct hlist_head *
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l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
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{
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return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
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}
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/* Session hash list.
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* The session_id SHOULD be random according to RFC2661, but several
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* L2TP implementations (Cisco and Microsoft) use incrementing
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* session_ids. So we do a real hash on the session_id, rather than a
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* simple bitmask.
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*/
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static inline struct hlist_head *
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l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
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{
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return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
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}
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static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
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{
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trace_free_tunnel(tunnel);
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sock_put(tunnel->sock);
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/* the tunnel is freed in the socket destructor */
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}
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static void l2tp_session_free(struct l2tp_session *session)
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{
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trace_free_session(session);
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if (session->tunnel)
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l2tp_tunnel_dec_refcount(session->tunnel);
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kfree(session);
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}
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struct l2tp_tunnel *l2tp_sk_to_tunnel(struct sock *sk)
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{
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struct l2tp_tunnel *tunnel = sk->sk_user_data;
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if (tunnel)
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if (WARN_ON(tunnel->magic != L2TP_TUNNEL_MAGIC))
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return NULL;
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return tunnel;
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}
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EXPORT_SYMBOL_GPL(l2tp_sk_to_tunnel);
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void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
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{
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refcount_inc(&tunnel->ref_count);
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}
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EXPORT_SYMBOL_GPL(l2tp_tunnel_inc_refcount);
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void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
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{
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if (refcount_dec_and_test(&tunnel->ref_count))
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l2tp_tunnel_free(tunnel);
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}
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EXPORT_SYMBOL_GPL(l2tp_tunnel_dec_refcount);
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void l2tp_session_inc_refcount(struct l2tp_session *session)
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{
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refcount_inc(&session->ref_count);
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}
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EXPORT_SYMBOL_GPL(l2tp_session_inc_refcount);
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void l2tp_session_dec_refcount(struct l2tp_session *session)
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{
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if (refcount_dec_and_test(&session->ref_count))
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l2tp_session_free(session);
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}
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EXPORT_SYMBOL_GPL(l2tp_session_dec_refcount);
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/* Lookup a tunnel. A new reference is held on the returned tunnel. */
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struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id)
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{
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const struct l2tp_net *pn = l2tp_pernet(net);
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struct l2tp_tunnel *tunnel;
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rcu_read_lock_bh();
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tunnel = idr_find(&pn->l2tp_tunnel_idr, tunnel_id);
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if (tunnel && refcount_inc_not_zero(&tunnel->ref_count)) {
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rcu_read_unlock_bh();
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return tunnel;
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}
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rcu_read_unlock_bh();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_tunnel_get);
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struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth)
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{
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struct l2tp_net *pn = l2tp_pernet(net);
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unsigned long tunnel_id, tmp;
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struct l2tp_tunnel *tunnel;
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int count = 0;
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rcu_read_lock_bh();
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idr_for_each_entry_ul(&pn->l2tp_tunnel_idr, tunnel, tmp, tunnel_id) {
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if (tunnel && ++count > nth &&
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refcount_inc_not_zero(&tunnel->ref_count)) {
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rcu_read_unlock_bh();
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return tunnel;
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}
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}
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rcu_read_unlock_bh();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_tunnel_get_nth);
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struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel,
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u32 session_id)
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{
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struct hlist_head *session_list;
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struct l2tp_session *session;
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session_list = l2tp_session_id_hash(tunnel, session_id);
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rcu_read_lock_bh();
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hlist_for_each_entry_rcu(session, session_list, hlist)
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if (session->session_id == session_id) {
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l2tp_session_inc_refcount(session);
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rcu_read_unlock_bh();
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return session;
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}
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rcu_read_unlock_bh();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_tunnel_get_session);
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struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id)
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{
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struct hlist_head *session_list;
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struct l2tp_session *session;
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session_list = l2tp_session_id_hash_2(l2tp_pernet(net), session_id);
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rcu_read_lock_bh();
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hlist_for_each_entry_rcu(session, session_list, global_hlist)
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if (session->session_id == session_id) {
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l2tp_session_inc_refcount(session);
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rcu_read_unlock_bh();
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return session;
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}
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rcu_read_unlock_bh();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_session_get);
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struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth)
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{
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int hash;
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struct l2tp_session *session;
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int count = 0;
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rcu_read_lock_bh();
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for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
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hlist_for_each_entry_rcu(session, &tunnel->session_hlist[hash], hlist) {
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if (++count > nth) {
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l2tp_session_inc_refcount(session);
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rcu_read_unlock_bh();
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return session;
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}
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}
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}
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rcu_read_unlock_bh();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_session_get_nth);
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/* Lookup a session by interface name.
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* This is very inefficient but is only used by management interfaces.
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*/
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struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
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const char *ifname)
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{
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struct l2tp_net *pn = l2tp_pernet(net);
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int hash;
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struct l2tp_session *session;
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rcu_read_lock_bh();
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for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
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hlist_for_each_entry_rcu(session, &pn->l2tp_session_hlist[hash], global_hlist) {
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if (!strcmp(session->ifname, ifname)) {
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l2tp_session_inc_refcount(session);
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rcu_read_unlock_bh();
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return session;
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}
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}
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}
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rcu_read_unlock_bh();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname);
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int l2tp_session_register(struct l2tp_session *session,
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struct l2tp_tunnel *tunnel)
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{
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struct l2tp_session *session_walk;
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struct hlist_head *g_head;
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struct hlist_head *head;
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struct l2tp_net *pn;
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int err;
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head = l2tp_session_id_hash(tunnel, session->session_id);
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spin_lock_bh(&tunnel->hlist_lock);
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if (!tunnel->acpt_newsess) {
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err = -ENODEV;
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goto err_tlock;
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}
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hlist_for_each_entry(session_walk, head, hlist)
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if (session_walk->session_id == session->session_id) {
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err = -EEXIST;
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goto err_tlock;
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}
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if (tunnel->version == L2TP_HDR_VER_3) {
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pn = l2tp_pernet(tunnel->l2tp_net);
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g_head = l2tp_session_id_hash_2(pn, session->session_id);
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spin_lock_bh(&pn->l2tp_session_hlist_lock);
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/* IP encap expects session IDs to be globally unique, while
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* UDP encap doesn't.
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*/
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hlist_for_each_entry(session_walk, g_head, global_hlist)
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if (session_walk->session_id == session->session_id &&
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(session_walk->tunnel->encap == L2TP_ENCAPTYPE_IP ||
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tunnel->encap == L2TP_ENCAPTYPE_IP)) {
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err = -EEXIST;
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goto err_tlock_pnlock;
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}
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l2tp_tunnel_inc_refcount(tunnel);
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hlist_add_head_rcu(&session->global_hlist, g_head);
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spin_unlock_bh(&pn->l2tp_session_hlist_lock);
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} else {
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l2tp_tunnel_inc_refcount(tunnel);
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}
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hlist_add_head_rcu(&session->hlist, head);
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spin_unlock_bh(&tunnel->hlist_lock);
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trace_register_session(session);
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return 0;
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err_tlock_pnlock:
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spin_unlock_bh(&pn->l2tp_session_hlist_lock);
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err_tlock:
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spin_unlock_bh(&tunnel->hlist_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(l2tp_session_register);
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|
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/*****************************************************************************
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* Receive data handling
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*****************************************************************************/
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/* Queue a skb in order. We come here only if the skb has an L2TP sequence
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* number.
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*/
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static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
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{
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struct sk_buff *skbp;
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struct sk_buff *tmp;
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u32 ns = L2TP_SKB_CB(skb)->ns;
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spin_lock_bh(&session->reorder_q.lock);
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skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
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if (L2TP_SKB_CB(skbp)->ns > ns) {
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__skb_queue_before(&session->reorder_q, skbp, skb);
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atomic_long_inc(&session->stats.rx_oos_packets);
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goto out;
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}
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}
|
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__skb_queue_tail(&session->reorder_q, skb);
|
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out:
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spin_unlock_bh(&session->reorder_q.lock);
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}
|
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|
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/* Dequeue a single skb.
|
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*/
|
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static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
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{
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struct l2tp_tunnel *tunnel = session->tunnel;
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int length = L2TP_SKB_CB(skb)->length;
|
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|
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/* We're about to requeue the skb, so return resources
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* to its current owner (a socket receive buffer).
|
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*/
|
|
skb_orphan(skb);
|
|
|
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atomic_long_inc(&tunnel->stats.rx_packets);
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atomic_long_add(length, &tunnel->stats.rx_bytes);
|
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atomic_long_inc(&session->stats.rx_packets);
|
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atomic_long_add(length, &session->stats.rx_bytes);
|
|
|
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if (L2TP_SKB_CB(skb)->has_seq) {
|
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/* Bump our Nr */
|
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session->nr++;
|
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session->nr &= session->nr_max;
|
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trace_session_seqnum_update(session);
|
|
}
|
|
|
|
/* call private receive handler */
|
|
if (session->recv_skb)
|
|
(*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
|
|
else
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kfree_skb(skb);
|
|
}
|
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|
|
/* Dequeue skbs from the session's reorder_q, subject to packet order.
|
|
* Skbs that have been in the queue for too long are simply discarded.
|
|
*/
|
|
static void l2tp_recv_dequeue(struct l2tp_session *session)
|
|
{
|
|
struct sk_buff *skb;
|
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struct sk_buff *tmp;
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|
|
/* If the pkt at the head of the queue has the nr that we
|
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* expect to send up next, dequeue it and any other
|
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* in-sequence packets behind it.
|
|
*/
|
|
start:
|
|
spin_lock_bh(&session->reorder_q.lock);
|
|
skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
|
|
struct l2tp_skb_cb *cb = L2TP_SKB_CB(skb);
|
|
|
|
/* If the packet has been pending on the queue for too long, discard it */
|
|
if (time_after(jiffies, cb->expires)) {
|
|
atomic_long_inc(&session->stats.rx_seq_discards);
|
|
atomic_long_inc(&session->stats.rx_errors);
|
|
trace_session_pkt_expired(session, cb->ns);
|
|
session->reorder_skip = 1;
|
|
__skb_unlink(skb, &session->reorder_q);
|
|
kfree_skb(skb);
|
|
continue;
|
|
}
|
|
|
|
if (cb->has_seq) {
|
|
if (session->reorder_skip) {
|
|
session->reorder_skip = 0;
|
|
session->nr = cb->ns;
|
|
trace_session_seqnum_reset(session);
|
|
}
|
|
if (cb->ns != session->nr)
|
|
goto out;
|
|
}
|
|
__skb_unlink(skb, &session->reorder_q);
|
|
|
|
/* Process the skb. We release the queue lock while we
|
|
* do so to let other contexts process the queue.
|
|
*/
|
|
spin_unlock_bh(&session->reorder_q.lock);
|
|
l2tp_recv_dequeue_skb(session, skb);
|
|
goto start;
|
|
}
|
|
|
|
out:
|
|
spin_unlock_bh(&session->reorder_q.lock);
|
|
}
|
|
|
|
static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr)
|
|
{
|
|
u32 nws;
|
|
|
|
if (nr >= session->nr)
|
|
nws = nr - session->nr;
|
|
else
|
|
nws = (session->nr_max + 1) - (session->nr - nr);
|
|
|
|
return nws < session->nr_window_size;
|
|
}
|
|
|
|
/* If packet has sequence numbers, queue it if acceptable. Returns 0 if
|
|
* acceptable, else non-zero.
|
|
*/
|
|
static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb)
|
|
{
|
|
struct l2tp_skb_cb *cb = L2TP_SKB_CB(skb);
|
|
|
|
if (!l2tp_seq_check_rx_window(session, cb->ns)) {
|
|
/* Packet sequence number is outside allowed window.
|
|
* Discard it.
|
|
*/
|
|
trace_session_pkt_outside_rx_window(session, cb->ns);
|
|
goto discard;
|
|
}
|
|
|
|
if (session->reorder_timeout != 0) {
|
|
/* Packet reordering enabled. Add skb to session's
|
|
* reorder queue, in order of ns.
|
|
*/
|
|
l2tp_recv_queue_skb(session, skb);
|
|
goto out;
|
|
}
|
|
|
|
/* Packet reordering disabled. Discard out-of-sequence packets, while
|
|
* tracking the number if in-sequence packets after the first OOS packet
|
|
* is seen. After nr_oos_count_max in-sequence packets, reset the
|
|
* sequence number to re-enable packet reception.
|
|
*/
|
|
if (cb->ns == session->nr) {
|
|
skb_queue_tail(&session->reorder_q, skb);
|
|
} else {
|
|
u32 nr_oos = cb->ns;
|
|
u32 nr_next = (session->nr_oos + 1) & session->nr_max;
|
|
|
|
if (nr_oos == nr_next)
|
|
session->nr_oos_count++;
|
|
else
|
|
session->nr_oos_count = 0;
|
|
|
|
session->nr_oos = nr_oos;
|
|
if (session->nr_oos_count > session->nr_oos_count_max) {
|
|
session->reorder_skip = 1;
|
|
}
|
|
if (!session->reorder_skip) {
|
|
atomic_long_inc(&session->stats.rx_seq_discards);
|
|
trace_session_pkt_oos(session, cb->ns);
|
|
goto discard;
|
|
}
|
|
skb_queue_tail(&session->reorder_q, skb);
|
|
}
|
|
|
|
out:
|
|
return 0;
|
|
|
|
discard:
|
|
return 1;
|
|
}
|
|
|
|
/* Do receive processing of L2TP data frames. We handle both L2TPv2
|
|
* and L2TPv3 data frames here.
|
|
*
|
|
* L2TPv2 Data Message Header
|
|
*
|
|
* 0 1 2 3
|
|
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | Tunnel ID | Session ID |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | Ns (opt) | Nr (opt) |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | Offset Size (opt) | Offset pad... (opt)
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
*
|
|
* Data frames are marked by T=0. All other fields are the same as
|
|
* those in L2TP control frames.
|
|
*
|
|
* L2TPv3 Data Message Header
|
|
*
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | L2TP Session Header |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | L2-Specific Sublayer |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | Tunnel Payload ...
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
*
|
|
* L2TPv3 Session Header Over IP
|
|
*
|
|
* 0 1 2 3
|
|
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | Session ID |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | Cookie (optional, maximum 64 bits)...
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
*
|
|
* L2TPv3 L2-Specific Sublayer Format
|
|
*
|
|
* 0 1 2 3
|
|
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* |x|S|x|x|x|x|x|x| Sequence Number |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
*
|
|
* Cookie value and sublayer format are negotiated with the peer when
|
|
* the session is set up. Unlike L2TPv2, we do not need to parse the
|
|
* packet header to determine if optional fields are present.
|
|
*
|
|
* Caller must already have parsed the frame and determined that it is
|
|
* a data (not control) frame before coming here. Fields up to the
|
|
* session-id have already been parsed and ptr points to the data
|
|
* after the session-id.
|
|
*/
|
|
void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
|
|
unsigned char *ptr, unsigned char *optr, u16 hdrflags,
|
|
int length)
|
|
{
|
|
struct l2tp_tunnel *tunnel = session->tunnel;
|
|
int offset;
|
|
|
|
/* Parse and check optional cookie */
|
|
if (session->peer_cookie_len > 0) {
|
|
if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
|
|
pr_debug_ratelimited("%s: cookie mismatch (%u/%u). Discarding.\n",
|
|
tunnel->name, tunnel->tunnel_id,
|
|
session->session_id);
|
|
atomic_long_inc(&session->stats.rx_cookie_discards);
|
|
goto discard;
|
|
}
|
|
ptr += session->peer_cookie_len;
|
|
}
|
|
|
|
/* Handle the optional sequence numbers. Sequence numbers are
|
|
* in different places for L2TPv2 and L2TPv3.
|
|
*
|
|
* If we are the LAC, enable/disable sequence numbers under
|
|
* the control of the LNS. If no sequence numbers present but
|
|
* we were expecting them, discard frame.
|
|
*/
|
|
L2TP_SKB_CB(skb)->has_seq = 0;
|
|
if (tunnel->version == L2TP_HDR_VER_2) {
|
|
if (hdrflags & L2TP_HDRFLAG_S) {
|
|
/* Store L2TP info in the skb */
|
|
L2TP_SKB_CB(skb)->ns = ntohs(*(__be16 *)ptr);
|
|
L2TP_SKB_CB(skb)->has_seq = 1;
|
|
ptr += 2;
|
|
/* Skip past nr in the header */
|
|
ptr += 2;
|
|
|
|
}
|
|
} else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
|
|
u32 l2h = ntohl(*(__be32 *)ptr);
|
|
|
|
if (l2h & 0x40000000) {
|
|
/* Store L2TP info in the skb */
|
|
L2TP_SKB_CB(skb)->ns = l2h & 0x00ffffff;
|
|
L2TP_SKB_CB(skb)->has_seq = 1;
|
|
}
|
|
ptr += 4;
|
|
}
|
|
|
|
if (L2TP_SKB_CB(skb)->has_seq) {
|
|
/* Received a packet with sequence numbers. If we're the LAC,
|
|
* check if we sre sending sequence numbers and if not,
|
|
* configure it so.
|
|
*/
|
|
if (!session->lns_mode && !session->send_seq) {
|
|
trace_session_seqnum_lns_enable(session);
|
|
session->send_seq = 1;
|
|
l2tp_session_set_header_len(session, tunnel->version);
|
|
}
|
|
} else {
|
|
/* No sequence numbers.
|
|
* If user has configured mandatory sequence numbers, discard.
|
|
*/
|
|
if (session->recv_seq) {
|
|
pr_debug_ratelimited("%s: recv data has no seq numbers when required. Discarding.\n",
|
|
session->name);
|
|
atomic_long_inc(&session->stats.rx_seq_discards);
|
|
goto discard;
|
|
}
|
|
|
|
/* If we're the LAC and we're sending sequence numbers, the
|
|
* LNS has requested that we no longer send sequence numbers.
|
|
* If we're the LNS and we're sending sequence numbers, the
|
|
* LAC is broken. Discard the frame.
|
|
*/
|
|
if (!session->lns_mode && session->send_seq) {
|
|
trace_session_seqnum_lns_disable(session);
|
|
session->send_seq = 0;
|
|
l2tp_session_set_header_len(session, tunnel->version);
|
|
} else if (session->send_seq) {
|
|
pr_debug_ratelimited("%s: recv data has no seq numbers when required. Discarding.\n",
|
|
session->name);
|
|
atomic_long_inc(&session->stats.rx_seq_discards);
|
|
goto discard;
|
|
}
|
|
}
|
|
|
|
/* Session data offset is defined only for L2TPv2 and is
|
|
* indicated by an optional 16-bit value in the header.
|
|
*/
|
|
if (tunnel->version == L2TP_HDR_VER_2) {
|
|
/* If offset bit set, skip it. */
|
|
if (hdrflags & L2TP_HDRFLAG_O) {
|
|
offset = ntohs(*(__be16 *)ptr);
|
|
ptr += 2 + offset;
|
|
}
|
|
}
|
|
|
|
offset = ptr - optr;
|
|
if (!pskb_may_pull(skb, offset))
|
|
goto discard;
|
|
|
|
__skb_pull(skb, offset);
|
|
|
|
/* Prepare skb for adding to the session's reorder_q. Hold
|
|
* packets for max reorder_timeout or 1 second if not
|
|
* reordering.
|
|
*/
|
|
L2TP_SKB_CB(skb)->length = length;
|
|
L2TP_SKB_CB(skb)->expires = jiffies +
|
|
(session->reorder_timeout ? session->reorder_timeout : HZ);
|
|
|
|
/* Add packet to the session's receive queue. Reordering is done here, if
|
|
* enabled. Saved L2TP protocol info is stored in skb->sb[].
|
|
*/
|
|
if (L2TP_SKB_CB(skb)->has_seq) {
|
|
if (l2tp_recv_data_seq(session, skb))
|
|
goto discard;
|
|
} else {
|
|
/* No sequence numbers. Add the skb to the tail of the
|
|
* reorder queue. This ensures that it will be
|
|
* delivered after all previous sequenced skbs.
|
|
*/
|
|
skb_queue_tail(&session->reorder_q, skb);
|
|
}
|
|
|
|
/* Try to dequeue as many skbs from reorder_q as we can. */
|
|
l2tp_recv_dequeue(session);
|
|
|
|
return;
|
|
|
|
discard:
|
|
atomic_long_inc(&session->stats.rx_errors);
|
|
kfree_skb(skb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_recv_common);
|
|
|
|
/* Drop skbs from the session's reorder_q
|
|
*/
|
|
static void l2tp_session_queue_purge(struct l2tp_session *session)
|
|
{
|
|
struct sk_buff *skb = NULL;
|
|
|
|
while ((skb = skb_dequeue(&session->reorder_q))) {
|
|
atomic_long_inc(&session->stats.rx_errors);
|
|
kfree_skb(skb);
|
|
}
|
|
}
|
|
|
|
/* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
|
|
* here. The skb is not on a list when we get here.
|
|
* Returns 0 if the packet was a data packet and was successfully passed on.
|
|
* Returns 1 if the packet was not a good data packet and could not be
|
|
* forwarded. All such packets are passed up to userspace to deal with.
|
|
*/
|
|
static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb)
|
|
{
|
|
struct l2tp_session *session = NULL;
|
|
unsigned char *ptr, *optr;
|
|
u16 hdrflags;
|
|
u32 tunnel_id, session_id;
|
|
u16 version;
|
|
int length;
|
|
|
|
/* UDP has verified checksum */
|
|
|
|
/* UDP always verifies the packet length. */
|
|
__skb_pull(skb, sizeof(struct udphdr));
|
|
|
|
/* Short packet? */
|
|
if (!pskb_may_pull(skb, L2TP_HDR_SIZE_MAX)) {
|
|
pr_debug_ratelimited("%s: recv short packet (len=%d)\n",
|
|
tunnel->name, skb->len);
|
|
goto invalid;
|
|
}
|
|
|
|
/* Point to L2TP header */
|
|
optr = skb->data;
|
|
ptr = skb->data;
|
|
|
|
/* Get L2TP header flags */
|
|
hdrflags = ntohs(*(__be16 *)ptr);
|
|
|
|
/* Check protocol version */
|
|
version = hdrflags & L2TP_HDR_VER_MASK;
|
|
if (version != tunnel->version) {
|
|
pr_debug_ratelimited("%s: recv protocol version mismatch: got %d expected %d\n",
|
|
tunnel->name, version, tunnel->version);
|
|
goto invalid;
|
|
}
|
|
|
|
/* Get length of L2TP packet */
|
|
length = skb->len;
|
|
|
|
/* If type is control packet, it is handled by userspace. */
|
|
if (hdrflags & L2TP_HDRFLAG_T)
|
|
goto pass;
|
|
|
|
/* Skip flags */
|
|
ptr += 2;
|
|
|
|
if (tunnel->version == L2TP_HDR_VER_2) {
|
|
/* If length is present, skip it */
|
|
if (hdrflags & L2TP_HDRFLAG_L)
|
|
ptr += 2;
|
|
|
|
/* Extract tunnel and session ID */
|
|
tunnel_id = ntohs(*(__be16 *)ptr);
|
|
ptr += 2;
|
|
session_id = ntohs(*(__be16 *)ptr);
|
|
ptr += 2;
|
|
} else {
|
|
ptr += 2; /* skip reserved bits */
|
|
tunnel_id = tunnel->tunnel_id;
|
|
session_id = ntohl(*(__be32 *)ptr);
|
|
ptr += 4;
|
|
}
|
|
|
|
/* Find the session context */
|
|
session = l2tp_tunnel_get_session(tunnel, session_id);
|
|
if (!session || !session->recv_skb) {
|
|
if (session)
|
|
l2tp_session_dec_refcount(session);
|
|
|
|
/* Not found? Pass to userspace to deal with */
|
|
pr_debug_ratelimited("%s: no session found (%u/%u). Passing up.\n",
|
|
tunnel->name, tunnel_id, session_id);
|
|
goto pass;
|
|
}
|
|
|
|
if (tunnel->version == L2TP_HDR_VER_3 &&
|
|
l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) {
|
|
l2tp_session_dec_refcount(session);
|
|
goto invalid;
|
|
}
|
|
|
|
l2tp_recv_common(session, skb, ptr, optr, hdrflags, length);
|
|
l2tp_session_dec_refcount(session);
|
|
|
|
return 0;
|
|
|
|
invalid:
|
|
atomic_long_inc(&tunnel->stats.rx_invalid);
|
|
|
|
pass:
|
|
/* Put UDP header back */
|
|
__skb_push(skb, sizeof(struct udphdr));
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* UDP encapsulation receive handler. See net/ipv4/udp.c.
|
|
* Return codes:
|
|
* 0 : success.
|
|
* <0: error
|
|
* >0: skb should be passed up to userspace as UDP.
|
|
*/
|
|
int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
struct l2tp_tunnel *tunnel;
|
|
|
|
/* Note that this is called from the encap_rcv hook inside an
|
|
* RCU-protected region, but without the socket being locked.
|
|
* Hence we use rcu_dereference_sk_user_data to access the
|
|
* tunnel data structure rather the usual l2tp_sk_to_tunnel
|
|
* accessor function.
|
|
*/
|
|
tunnel = rcu_dereference_sk_user_data(sk);
|
|
if (!tunnel)
|
|
goto pass_up;
|
|
if (WARN_ON(tunnel->magic != L2TP_TUNNEL_MAGIC))
|
|
goto pass_up;
|
|
|
|
if (l2tp_udp_recv_core(tunnel, skb))
|
|
goto pass_up;
|
|
|
|
return 0;
|
|
|
|
pass_up:
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
|
|
|
|
/************************************************************************
|
|
* Transmit handling
|
|
***********************************************************************/
|
|
|
|
/* Build an L2TP header for the session into the buffer provided.
|
|
*/
|
|
static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
|
|
{
|
|
struct l2tp_tunnel *tunnel = session->tunnel;
|
|
__be16 *bufp = buf;
|
|
__be16 *optr = buf;
|
|
u16 flags = L2TP_HDR_VER_2;
|
|
u32 tunnel_id = tunnel->peer_tunnel_id;
|
|
u32 session_id = session->peer_session_id;
|
|
|
|
if (session->send_seq)
|
|
flags |= L2TP_HDRFLAG_S;
|
|
|
|
/* Setup L2TP header. */
|
|
*bufp++ = htons(flags);
|
|
*bufp++ = htons(tunnel_id);
|
|
*bufp++ = htons(session_id);
|
|
if (session->send_seq) {
|
|
*bufp++ = htons(session->ns);
|
|
*bufp++ = 0;
|
|
session->ns++;
|
|
session->ns &= 0xffff;
|
|
trace_session_seqnum_update(session);
|
|
}
|
|
|
|
return bufp - optr;
|
|
}
|
|
|
|
static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
|
|
{
|
|
struct l2tp_tunnel *tunnel = session->tunnel;
|
|
char *bufp = buf;
|
|
char *optr = bufp;
|
|
|
|
/* Setup L2TP header. The header differs slightly for UDP and
|
|
* IP encapsulations. For UDP, there is 4 bytes of flags.
|
|
*/
|
|
if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
|
|
u16 flags = L2TP_HDR_VER_3;
|
|
*((__be16 *)bufp) = htons(flags);
|
|
bufp += 2;
|
|
*((__be16 *)bufp) = 0;
|
|
bufp += 2;
|
|
}
|
|
|
|
*((__be32 *)bufp) = htonl(session->peer_session_id);
|
|
bufp += 4;
|
|
if (session->cookie_len) {
|
|
memcpy(bufp, &session->cookie[0], session->cookie_len);
|
|
bufp += session->cookie_len;
|
|
}
|
|
if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
|
|
u32 l2h = 0;
|
|
|
|
if (session->send_seq) {
|
|
l2h = 0x40000000 | session->ns;
|
|
session->ns++;
|
|
session->ns &= 0xffffff;
|
|
trace_session_seqnum_update(session);
|
|
}
|
|
|
|
*((__be32 *)bufp) = htonl(l2h);
|
|
bufp += 4;
|
|
}
|
|
|
|
return bufp - optr;
|
|
}
|
|
|
|
/* Queue the packet to IP for output: tunnel socket lock must be held */
|
|
static int l2tp_xmit_queue(struct l2tp_tunnel *tunnel, struct sk_buff *skb, struct flowi *fl)
|
|
{
|
|
int err;
|
|
|
|
skb->ignore_df = 1;
|
|
skb_dst_drop(skb);
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (l2tp_sk_is_v6(tunnel->sock))
|
|
err = inet6_csk_xmit(tunnel->sock, skb, NULL);
|
|
else
|
|
#endif
|
|
err = ip_queue_xmit(tunnel->sock, skb, fl);
|
|
|
|
return err >= 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP;
|
|
}
|
|
|
|
static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, unsigned int *len)
|
|
{
|
|
struct l2tp_tunnel *tunnel = session->tunnel;
|
|
unsigned int data_len = skb->len;
|
|
struct sock *sk = tunnel->sock;
|
|
int headroom, uhlen, udp_len;
|
|
int ret = NET_XMIT_SUCCESS;
|
|
struct inet_sock *inet;
|
|
struct udphdr *uh;
|
|
|
|
/* Check that there's enough headroom in the skb to insert IP,
|
|
* UDP and L2TP headers. If not enough, expand it to
|
|
* make room. Adjust truesize.
|
|
*/
|
|
uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(*uh) : 0;
|
|
headroom = NET_SKB_PAD + sizeof(struct iphdr) + uhlen + session->hdr_len;
|
|
if (skb_cow_head(skb, headroom)) {
|
|
kfree_skb(skb);
|
|
return NET_XMIT_DROP;
|
|
}
|
|
|
|
/* Setup L2TP header */
|
|
if (tunnel->version == L2TP_HDR_VER_2)
|
|
l2tp_build_l2tpv2_header(session, __skb_push(skb, session->hdr_len));
|
|
else
|
|
l2tp_build_l2tpv3_header(session, __skb_push(skb, session->hdr_len));
|
|
|
|
/* Reset skb netfilter state */
|
|
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
|
|
IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED);
|
|
nf_reset_ct(skb);
|
|
|
|
bh_lock_sock_nested(sk);
|
|
if (sock_owned_by_user(sk)) {
|
|
kfree_skb(skb);
|
|
ret = NET_XMIT_DROP;
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* The user-space may change the connection status for the user-space
|
|
* provided socket at run time: we must check it under the socket lock
|
|
*/
|
|
if (tunnel->fd >= 0 && sk->sk_state != TCP_ESTABLISHED) {
|
|
kfree_skb(skb);
|
|
ret = NET_XMIT_DROP;
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* Report transmitted length before we add encap header, which keeps
|
|
* statistics consistent for both UDP and IP encap tx/rx paths.
|
|
*/
|
|
*len = skb->len;
|
|
|
|
inet = inet_sk(sk);
|
|
switch (tunnel->encap) {
|
|
case L2TP_ENCAPTYPE_UDP:
|
|
/* Setup UDP header */
|
|
__skb_push(skb, sizeof(*uh));
|
|
skb_reset_transport_header(skb);
|
|
uh = udp_hdr(skb);
|
|
uh->source = inet->inet_sport;
|
|
uh->dest = inet->inet_dport;
|
|
udp_len = uhlen + session->hdr_len + data_len;
|
|
uh->len = htons(udp_len);
|
|
|
|
/* Calculate UDP checksum if configured to do so */
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (l2tp_sk_is_v6(sk))
|
|
udp6_set_csum(udp_get_no_check6_tx(sk),
|
|
skb, &inet6_sk(sk)->saddr,
|
|
&sk->sk_v6_daddr, udp_len);
|
|
else
|
|
#endif
|
|
udp_set_csum(sk->sk_no_check_tx, skb, inet->inet_saddr,
|
|
inet->inet_daddr, udp_len);
|
|
break;
|
|
|
|
case L2TP_ENCAPTYPE_IP:
|
|
break;
|
|
}
|
|
|
|
ret = l2tp_xmit_queue(tunnel, skb, &inet->cork.fl);
|
|
|
|
out_unlock:
|
|
bh_unlock_sock(sk);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* If caller requires the skb to have a ppp header, the header must be
|
|
* inserted in the skb data before calling this function.
|
|
*/
|
|
int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb)
|
|
{
|
|
unsigned int len = 0;
|
|
int ret;
|
|
|
|
ret = l2tp_xmit_core(session, skb, &len);
|
|
if (ret == NET_XMIT_SUCCESS) {
|
|
atomic_long_inc(&session->tunnel->stats.tx_packets);
|
|
atomic_long_add(len, &session->tunnel->stats.tx_bytes);
|
|
atomic_long_inc(&session->stats.tx_packets);
|
|
atomic_long_add(len, &session->stats.tx_bytes);
|
|
} else {
|
|
atomic_long_inc(&session->tunnel->stats.tx_errors);
|
|
atomic_long_inc(&session->stats.tx_errors);
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
|
|
|
|
/*****************************************************************************
|
|
* Tinnel and session create/destroy.
|
|
*****************************************************************************/
|
|
|
|
/* Tunnel socket destruct hook.
|
|
* The tunnel context is deleted only when all session sockets have been
|
|
* closed.
|
|
*/
|
|
static void l2tp_tunnel_destruct(struct sock *sk)
|
|
{
|
|
struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk);
|
|
|
|
if (!tunnel)
|
|
goto end;
|
|
|
|
/* Disable udp encapsulation */
|
|
switch (tunnel->encap) {
|
|
case L2TP_ENCAPTYPE_UDP:
|
|
/* No longer an encapsulation socket. See net/ipv4/udp.c */
|
|
(udp_sk(sk))->encap_type = 0;
|
|
(udp_sk(sk))->encap_rcv = NULL;
|
|
(udp_sk(sk))->encap_destroy = NULL;
|
|
break;
|
|
case L2TP_ENCAPTYPE_IP:
|
|
break;
|
|
}
|
|
|
|
/* Remove hooks into tunnel socket */
|
|
write_lock_bh(&sk->sk_callback_lock);
|
|
sk->sk_destruct = tunnel->old_sk_destruct;
|
|
sk->sk_user_data = NULL;
|
|
write_unlock_bh(&sk->sk_callback_lock);
|
|
|
|
/* Call the original destructor */
|
|
if (sk->sk_destruct)
|
|
(*sk->sk_destruct)(sk);
|
|
|
|
kfree_rcu(tunnel, rcu);
|
|
end:
|
|
return;
|
|
}
|
|
|
|
/* Remove an l2tp session from l2tp_core's hash lists. */
|
|
static void l2tp_session_unhash(struct l2tp_session *session)
|
|
{
|
|
struct l2tp_tunnel *tunnel = session->tunnel;
|
|
|
|
/* Remove the session from core hashes */
|
|
if (tunnel) {
|
|
/* Remove from the per-tunnel hash */
|
|
spin_lock_bh(&tunnel->hlist_lock);
|
|
hlist_del_init_rcu(&session->hlist);
|
|
spin_unlock_bh(&tunnel->hlist_lock);
|
|
|
|
/* For L2TPv3 we have a per-net hash: remove from there, too */
|
|
if (tunnel->version != L2TP_HDR_VER_2) {
|
|
struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
|
|
|
|
spin_lock_bh(&pn->l2tp_session_hlist_lock);
|
|
hlist_del_init_rcu(&session->global_hlist);
|
|
spin_unlock_bh(&pn->l2tp_session_hlist_lock);
|
|
}
|
|
|
|
synchronize_rcu();
|
|
}
|
|
}
|
|
|
|
/* When the tunnel is closed, all the attached sessions need to go too.
|
|
*/
|
|
static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
|
|
{
|
|
struct l2tp_session *session;
|
|
int hash;
|
|
|
|
spin_lock_bh(&tunnel->hlist_lock);
|
|
tunnel->acpt_newsess = false;
|
|
for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
|
|
again:
|
|
hlist_for_each_entry_rcu(session, &tunnel->session_hlist[hash], hlist) {
|
|
hlist_del_init_rcu(&session->hlist);
|
|
|
|
spin_unlock_bh(&tunnel->hlist_lock);
|
|
l2tp_session_delete(session);
|
|
spin_lock_bh(&tunnel->hlist_lock);
|
|
|
|
/* Now restart from the beginning of this hash
|
|
* chain. We always remove a session from the
|
|
* list so we are guaranteed to make forward
|
|
* progress.
|
|
*/
|
|
goto again;
|
|
}
|
|
}
|
|
spin_unlock_bh(&tunnel->hlist_lock);
|
|
}
|
|
|
|
/* Tunnel socket destroy hook for UDP encapsulation */
|
|
static void l2tp_udp_encap_destroy(struct sock *sk)
|
|
{
|
|
struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk);
|
|
|
|
if (tunnel)
|
|
l2tp_tunnel_delete(tunnel);
|
|
}
|
|
|
|
static void l2tp_tunnel_remove(struct net *net, struct l2tp_tunnel *tunnel)
|
|
{
|
|
struct l2tp_net *pn = l2tp_pernet(net);
|
|
|
|
spin_lock_bh(&pn->l2tp_tunnel_idr_lock);
|
|
idr_remove(&pn->l2tp_tunnel_idr, tunnel->tunnel_id);
|
|
spin_unlock_bh(&pn->l2tp_tunnel_idr_lock);
|
|
}
|
|
|
|
/* Workqueue tunnel deletion function */
|
|
static void l2tp_tunnel_del_work(struct work_struct *work)
|
|
{
|
|
struct l2tp_tunnel *tunnel = container_of(work, struct l2tp_tunnel,
|
|
del_work);
|
|
struct sock *sk = tunnel->sock;
|
|
struct socket *sock = sk->sk_socket;
|
|
|
|
l2tp_tunnel_closeall(tunnel);
|
|
|
|
/* If the tunnel socket was created within the kernel, use
|
|
* the sk API to release it here.
|
|
*/
|
|
if (tunnel->fd < 0) {
|
|
if (sock) {
|
|
kernel_sock_shutdown(sock, SHUT_RDWR);
|
|
sock_release(sock);
|
|
}
|
|
}
|
|
|
|
l2tp_tunnel_remove(tunnel->l2tp_net, tunnel);
|
|
/* drop initial ref */
|
|
l2tp_tunnel_dec_refcount(tunnel);
|
|
|
|
/* drop workqueue ref */
|
|
l2tp_tunnel_dec_refcount(tunnel);
|
|
}
|
|
|
|
/* Create a socket for the tunnel, if one isn't set up by
|
|
* userspace. This is used for static tunnels where there is no
|
|
* managing L2TP daemon.
|
|
*
|
|
* Since we don't want these sockets to keep a namespace alive by
|
|
* themselves, we drop the socket's namespace refcount after creation.
|
|
* These sockets are freed when the namespace exits using the pernet
|
|
* exit hook.
|
|
*/
|
|
static int l2tp_tunnel_sock_create(struct net *net,
|
|
u32 tunnel_id,
|
|
u32 peer_tunnel_id,
|
|
struct l2tp_tunnel_cfg *cfg,
|
|
struct socket **sockp)
|
|
{
|
|
int err = -EINVAL;
|
|
struct socket *sock = NULL;
|
|
struct udp_port_cfg udp_conf;
|
|
|
|
switch (cfg->encap) {
|
|
case L2TP_ENCAPTYPE_UDP:
|
|
memset(&udp_conf, 0, sizeof(udp_conf));
|
|
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (cfg->local_ip6 && cfg->peer_ip6) {
|
|
udp_conf.family = AF_INET6;
|
|
memcpy(&udp_conf.local_ip6, cfg->local_ip6,
|
|
sizeof(udp_conf.local_ip6));
|
|
memcpy(&udp_conf.peer_ip6, cfg->peer_ip6,
|
|
sizeof(udp_conf.peer_ip6));
|
|
udp_conf.use_udp6_tx_checksums =
|
|
!cfg->udp6_zero_tx_checksums;
|
|
udp_conf.use_udp6_rx_checksums =
|
|
!cfg->udp6_zero_rx_checksums;
|
|
} else
|
|
#endif
|
|
{
|
|
udp_conf.family = AF_INET;
|
|
udp_conf.local_ip = cfg->local_ip;
|
|
udp_conf.peer_ip = cfg->peer_ip;
|
|
udp_conf.use_udp_checksums = cfg->use_udp_checksums;
|
|
}
|
|
|
|
udp_conf.local_udp_port = htons(cfg->local_udp_port);
|
|
udp_conf.peer_udp_port = htons(cfg->peer_udp_port);
|
|
|
|
err = udp_sock_create(net, &udp_conf, &sock);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
break;
|
|
|
|
case L2TP_ENCAPTYPE_IP:
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (cfg->local_ip6 && cfg->peer_ip6) {
|
|
struct sockaddr_l2tpip6 ip6_addr = {0};
|
|
|
|
err = sock_create_kern(net, AF_INET6, SOCK_DGRAM,
|
|
IPPROTO_L2TP, &sock);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
ip6_addr.l2tp_family = AF_INET6;
|
|
memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
|
|
sizeof(ip6_addr.l2tp_addr));
|
|
ip6_addr.l2tp_conn_id = tunnel_id;
|
|
err = kernel_bind(sock, (struct sockaddr *)&ip6_addr,
|
|
sizeof(ip6_addr));
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
ip6_addr.l2tp_family = AF_INET6;
|
|
memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6,
|
|
sizeof(ip6_addr.l2tp_addr));
|
|
ip6_addr.l2tp_conn_id = peer_tunnel_id;
|
|
err = kernel_connect(sock,
|
|
(struct sockaddr *)&ip6_addr,
|
|
sizeof(ip6_addr), 0);
|
|
if (err < 0)
|
|
goto out;
|
|
} else
|
|
#endif
|
|
{
|
|
struct sockaddr_l2tpip ip_addr = {0};
|
|
|
|
err = sock_create_kern(net, AF_INET, SOCK_DGRAM,
|
|
IPPROTO_L2TP, &sock);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
ip_addr.l2tp_family = AF_INET;
|
|
ip_addr.l2tp_addr = cfg->local_ip;
|
|
ip_addr.l2tp_conn_id = tunnel_id;
|
|
err = kernel_bind(sock, (struct sockaddr *)&ip_addr,
|
|
sizeof(ip_addr));
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
ip_addr.l2tp_family = AF_INET;
|
|
ip_addr.l2tp_addr = cfg->peer_ip;
|
|
ip_addr.l2tp_conn_id = peer_tunnel_id;
|
|
err = kernel_connect(sock, (struct sockaddr *)&ip_addr,
|
|
sizeof(ip_addr), 0);
|
|
if (err < 0)
|
|
goto out;
|
|
}
|
|
break;
|
|
|
|
default:
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
*sockp = sock;
|
|
if (err < 0 && sock) {
|
|
kernel_sock_shutdown(sock, SHUT_RDWR);
|
|
sock_release(sock);
|
|
*sockp = NULL;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
int l2tp_tunnel_create(int fd, int version, u32 tunnel_id, u32 peer_tunnel_id,
|
|
struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp)
|
|
{
|
|
struct l2tp_tunnel *tunnel = NULL;
|
|
int err;
|
|
enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
|
|
|
|
if (cfg)
|
|
encap = cfg->encap;
|
|
|
|
tunnel = kzalloc(sizeof(*tunnel), GFP_KERNEL);
|
|
if (!tunnel) {
|
|
err = -ENOMEM;
|
|
goto err;
|
|
}
|
|
|
|
tunnel->version = version;
|
|
tunnel->tunnel_id = tunnel_id;
|
|
tunnel->peer_tunnel_id = peer_tunnel_id;
|
|
|
|
tunnel->magic = L2TP_TUNNEL_MAGIC;
|
|
sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
|
|
spin_lock_init(&tunnel->hlist_lock);
|
|
tunnel->acpt_newsess = true;
|
|
|
|
tunnel->encap = encap;
|
|
|
|
refcount_set(&tunnel->ref_count, 1);
|
|
tunnel->fd = fd;
|
|
|
|
/* Init delete workqueue struct */
|
|
INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work);
|
|
|
|
INIT_LIST_HEAD(&tunnel->list);
|
|
|
|
err = 0;
|
|
err:
|
|
if (tunnelp)
|
|
*tunnelp = tunnel;
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
|
|
|
|
static int l2tp_validate_socket(const struct sock *sk, const struct net *net,
|
|
enum l2tp_encap_type encap)
|
|
{
|
|
if (!net_eq(sock_net(sk), net))
|
|
return -EINVAL;
|
|
|
|
if (sk->sk_type != SOCK_DGRAM)
|
|
return -EPROTONOSUPPORT;
|
|
|
|
if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
|
|
return -EPROTONOSUPPORT;
|
|
|
|
if ((encap == L2TP_ENCAPTYPE_UDP && sk->sk_protocol != IPPROTO_UDP) ||
|
|
(encap == L2TP_ENCAPTYPE_IP && sk->sk_protocol != IPPROTO_L2TP))
|
|
return -EPROTONOSUPPORT;
|
|
|
|
if (sk->sk_user_data)
|
|
return -EBUSY;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
|
|
struct l2tp_tunnel_cfg *cfg)
|
|
{
|
|
struct l2tp_net *pn = l2tp_pernet(net);
|
|
u32 tunnel_id = tunnel->tunnel_id;
|
|
struct socket *sock;
|
|
struct sock *sk;
|
|
int ret;
|
|
|
|
spin_lock_bh(&pn->l2tp_tunnel_idr_lock);
|
|
ret = idr_alloc_u32(&pn->l2tp_tunnel_idr, NULL, &tunnel_id, tunnel_id,
|
|
GFP_ATOMIC);
|
|
spin_unlock_bh(&pn->l2tp_tunnel_idr_lock);
|
|
if (ret)
|
|
return ret == -ENOSPC ? -EEXIST : ret;
|
|
|
|
if (tunnel->fd < 0) {
|
|
ret = l2tp_tunnel_sock_create(net, tunnel->tunnel_id,
|
|
tunnel->peer_tunnel_id, cfg,
|
|
&sock);
|
|
if (ret < 0)
|
|
goto err;
|
|
} else {
|
|
sock = sockfd_lookup(tunnel->fd, &ret);
|
|
if (!sock)
|
|
goto err;
|
|
}
|
|
|
|
sk = sock->sk;
|
|
lock_sock(sk);
|
|
write_lock_bh(&sk->sk_callback_lock);
|
|
ret = l2tp_validate_socket(sk, net, tunnel->encap);
|
|
if (ret < 0)
|
|
goto err_inval_sock;
|
|
rcu_assign_sk_user_data(sk, tunnel);
|
|
write_unlock_bh(&sk->sk_callback_lock);
|
|
|
|
if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
|
|
struct udp_tunnel_sock_cfg udp_cfg = {
|
|
.sk_user_data = tunnel,
|
|
.encap_type = UDP_ENCAP_L2TPINUDP,
|
|
.encap_rcv = l2tp_udp_encap_recv,
|
|
.encap_destroy = l2tp_udp_encap_destroy,
|
|
};
|
|
|
|
setup_udp_tunnel_sock(net, sock, &udp_cfg);
|
|
}
|
|
|
|
tunnel->old_sk_destruct = sk->sk_destruct;
|
|
sk->sk_destruct = &l2tp_tunnel_destruct;
|
|
sk->sk_allocation = GFP_ATOMIC;
|
|
release_sock(sk);
|
|
|
|
sock_hold(sk);
|
|
tunnel->sock = sk;
|
|
tunnel->l2tp_net = net;
|
|
|
|
spin_lock_bh(&pn->l2tp_tunnel_idr_lock);
|
|
idr_replace(&pn->l2tp_tunnel_idr, tunnel, tunnel->tunnel_id);
|
|
spin_unlock_bh(&pn->l2tp_tunnel_idr_lock);
|
|
|
|
trace_register_tunnel(tunnel);
|
|
|
|
if (tunnel->fd >= 0)
|
|
sockfd_put(sock);
|
|
|
|
return 0;
|
|
|
|
err_inval_sock:
|
|
write_unlock_bh(&sk->sk_callback_lock);
|
|
release_sock(sk);
|
|
|
|
if (tunnel->fd < 0)
|
|
sock_release(sock);
|
|
else
|
|
sockfd_put(sock);
|
|
err:
|
|
l2tp_tunnel_remove(net, tunnel);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_tunnel_register);
|
|
|
|
/* This function is used by the netlink TUNNEL_DELETE command.
|
|
*/
|
|
void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
|
|
{
|
|
if (!test_and_set_bit(0, &tunnel->dead)) {
|
|
trace_delete_tunnel(tunnel);
|
|
l2tp_tunnel_inc_refcount(tunnel);
|
|
queue_work(l2tp_wq, &tunnel->del_work);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
|
|
|
|
void l2tp_session_delete(struct l2tp_session *session)
|
|
{
|
|
if (test_and_set_bit(0, &session->dead))
|
|
return;
|
|
|
|
trace_delete_session(session);
|
|
l2tp_session_unhash(session);
|
|
l2tp_session_queue_purge(session);
|
|
if (session->session_close)
|
|
(*session->session_close)(session);
|
|
|
|
l2tp_session_dec_refcount(session);
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_session_delete);
|
|
|
|
/* We come here whenever a session's send_seq, cookie_len or
|
|
* l2specific_type parameters are set.
|
|
*/
|
|
void l2tp_session_set_header_len(struct l2tp_session *session, int version)
|
|
{
|
|
if (version == L2TP_HDR_VER_2) {
|
|
session->hdr_len = 6;
|
|
if (session->send_seq)
|
|
session->hdr_len += 4;
|
|
} else {
|
|
session->hdr_len = 4 + session->cookie_len;
|
|
session->hdr_len += l2tp_get_l2specific_len(session);
|
|
if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
|
|
session->hdr_len += 4;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_session_set_header_len);
|
|
|
|
struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id,
|
|
u32 peer_session_id, struct l2tp_session_cfg *cfg)
|
|
{
|
|
struct l2tp_session *session;
|
|
|
|
session = kzalloc(sizeof(*session) + priv_size, GFP_KERNEL);
|
|
if (session) {
|
|
session->magic = L2TP_SESSION_MAGIC;
|
|
session->tunnel = tunnel;
|
|
|
|
session->session_id = session_id;
|
|
session->peer_session_id = peer_session_id;
|
|
session->nr = 0;
|
|
if (tunnel->version == L2TP_HDR_VER_2)
|
|
session->nr_max = 0xffff;
|
|
else
|
|
session->nr_max = 0xffffff;
|
|
session->nr_window_size = session->nr_max / 2;
|
|
session->nr_oos_count_max = 4;
|
|
|
|
/* Use NR of first received packet */
|
|
session->reorder_skip = 1;
|
|
|
|
sprintf(&session->name[0], "sess %u/%u",
|
|
tunnel->tunnel_id, session->session_id);
|
|
|
|
skb_queue_head_init(&session->reorder_q);
|
|
|
|
INIT_HLIST_NODE(&session->hlist);
|
|
INIT_HLIST_NODE(&session->global_hlist);
|
|
|
|
if (cfg) {
|
|
session->pwtype = cfg->pw_type;
|
|
session->send_seq = cfg->send_seq;
|
|
session->recv_seq = cfg->recv_seq;
|
|
session->lns_mode = cfg->lns_mode;
|
|
session->reorder_timeout = cfg->reorder_timeout;
|
|
session->l2specific_type = cfg->l2specific_type;
|
|
session->cookie_len = cfg->cookie_len;
|
|
memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len);
|
|
session->peer_cookie_len = cfg->peer_cookie_len;
|
|
memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len);
|
|
}
|
|
|
|
l2tp_session_set_header_len(session, tunnel->version);
|
|
|
|
refcount_set(&session->ref_count, 1);
|
|
|
|
return session;
|
|
}
|
|
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_session_create);
|
|
|
|
/*****************************************************************************
|
|
* Init and cleanup
|
|
*****************************************************************************/
|
|
|
|
static __net_init int l2tp_init_net(struct net *net)
|
|
{
|
|
struct l2tp_net *pn = net_generic(net, l2tp_net_id);
|
|
int hash;
|
|
|
|
idr_init(&pn->l2tp_tunnel_idr);
|
|
spin_lock_init(&pn->l2tp_tunnel_idr_lock);
|
|
|
|
for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
|
|
INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
|
|
|
|
spin_lock_init(&pn->l2tp_session_hlist_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static __net_exit void l2tp_exit_net(struct net *net)
|
|
{
|
|
struct l2tp_net *pn = l2tp_pernet(net);
|
|
struct l2tp_tunnel *tunnel = NULL;
|
|
unsigned long tunnel_id, tmp;
|
|
int hash;
|
|
|
|
rcu_read_lock_bh();
|
|
idr_for_each_entry_ul(&pn->l2tp_tunnel_idr, tunnel, tmp, tunnel_id) {
|
|
if (tunnel)
|
|
l2tp_tunnel_delete(tunnel);
|
|
}
|
|
rcu_read_unlock_bh();
|
|
|
|
if (l2tp_wq)
|
|
flush_workqueue(l2tp_wq);
|
|
rcu_barrier();
|
|
|
|
for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
|
|
WARN_ON_ONCE(!hlist_empty(&pn->l2tp_session_hlist[hash]));
|
|
idr_destroy(&pn->l2tp_tunnel_idr);
|
|
}
|
|
|
|
static struct pernet_operations l2tp_net_ops = {
|
|
.init = l2tp_init_net,
|
|
.exit = l2tp_exit_net,
|
|
.id = &l2tp_net_id,
|
|
.size = sizeof(struct l2tp_net),
|
|
};
|
|
|
|
static int __init l2tp_init(void)
|
|
{
|
|
int rc = 0;
|
|
|
|
rc = register_pernet_device(&l2tp_net_ops);
|
|
if (rc)
|
|
goto out;
|
|
|
|
l2tp_wq = alloc_workqueue("l2tp", WQ_UNBOUND, 0);
|
|
if (!l2tp_wq) {
|
|
pr_err("alloc_workqueue failed\n");
|
|
unregister_pernet_device(&l2tp_net_ops);
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION);
|
|
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
static void __exit l2tp_exit(void)
|
|
{
|
|
unregister_pernet_device(&l2tp_net_ops);
|
|
if (l2tp_wq) {
|
|
destroy_workqueue(l2tp_wq);
|
|
l2tp_wq = NULL;
|
|
}
|
|
}
|
|
|
|
module_init(l2tp_init);
|
|
module_exit(l2tp_exit);
|
|
|
|
MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
|
|
MODULE_DESCRIPTION("L2TP core");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_VERSION(L2TP_DRV_VERSION);
|