A peer connected via UDP may change its IP address without reconnecting (float).
Add support for detecting and updating the new peer IP/port in case of floating.
Signed-off-by: Antonio Quartulli antonio@openvpn.net --- drivers/net/ovpn/bind.c | 10 ++-- drivers/net/ovpn/io.c | 9 ++++ drivers/net/ovpn/peer.c | 128 ++++++++++++++++++++++++++++++++++++++++++++++-- drivers/net/ovpn/peer.h | 2 + 4 files changed, 138 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ovpn/bind.c b/drivers/net/ovpn/bind.c index b4d2ccec2ceddf43bc445b489cc62a578ef0ad0a..d17d078c5730bf4336dc87f45cdba3f6b8cad770 100644 --- a/drivers/net/ovpn/bind.c +++ b/drivers/net/ovpn/bind.c @@ -47,12 +47,8 @@ struct ovpn_bind *ovpn_bind_from_sockaddr(const struct sockaddr_storage *ss) * @new: the new bind to assign */ void ovpn_bind_reset(struct ovpn_peer *peer, struct ovpn_bind *new) + __must_hold(&peer->lock) { - struct ovpn_bind *old; - - spin_lock_bh(&peer->lock); - old = rcu_replace_pointer(peer->bind, new, true); - spin_unlock_bh(&peer->lock); - - kfree_rcu(old, rcu); + kfree_rcu(rcu_replace_pointer(peer->bind, new, + lockdep_is_held(&peer->lock)), rcu); } diff --git a/drivers/net/ovpn/io.c b/drivers/net/ovpn/io.c index 4e69f31382d2cb9ce4bc40f06cfbae47add5b5ba..8f2b4a85d20fbdb512de7ec312d391985e96b906 100644 --- a/drivers/net/ovpn/io.c +++ b/drivers/net/ovpn/io.c @@ -133,6 +133,15 @@ void ovpn_decrypt_post(void *data, int ret) /* keep track of last received authenticated packet for keepalive */ peer->last_recv = ktime_get_real_seconds();
+ if (peer->sock->sock->sk->sk_protocol == IPPROTO_UDP) { + /* check if this peer changed it's IP address and update + * state + */ + ovpn_peer_float(peer, skb); + /* update source endpoint for this peer */ + ovpn_peer_update_local_endpoint(peer, skb); + } + /* point to encapsulated IP packet */ __skb_pull(skb, payload_offset);
diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c index f9d8f1d1827fe67dc4b4e0bba41a5b110bb90819..891cf2fa6a81b46ac764ad4fd50d4456fa7ce5bd 100644 --- a/drivers/net/ovpn/peer.c +++ b/drivers/net/ovpn/peer.c @@ -94,6 +94,128 @@ struct ovpn_peer *ovpn_peer_new(struct ovpn_struct *ovpn, u32 id) return peer; }
+/** + * ovpn_peer_reset_sockaddr - recreate binding for peer + * @peer: peer to recreate the binding for + * @ss: sockaddr to use as remote endpoint for the binding + * @local_ip: local IP for the binding + * + * Return: 0 on success or a negative error code otherwise + */ +static int ovpn_peer_reset_sockaddr(struct ovpn_peer *peer, + const struct sockaddr_storage *ss, + const u8 *local_ip) + __must_hold(&peer->lock) +{ + struct ovpn_bind *bind; + size_t ip_len; + + /* create new ovpn_bind object */ + bind = ovpn_bind_from_sockaddr(ss); + if (IS_ERR(bind)) + return PTR_ERR(bind); + + if (local_ip) { + if (ss->ss_family == AF_INET) { + ip_len = sizeof(struct in_addr); + } else if (ss->ss_family == AF_INET6) { + ip_len = sizeof(struct in6_addr); + } else { + netdev_dbg(peer->ovpn->dev, "%s: invalid family for remote endpoint\n", + __func__); + kfree(bind); + return -EINVAL; + } + + memcpy(&bind->local, local_ip, ip_len); + } + + /* set binding */ + ovpn_bind_reset(peer, bind); + + return 0; +} + +#define ovpn_get_hash_head(_tbl, _key, _key_len) ({ \ + typeof(_tbl) *__tbl = &(_tbl); \ + (&(*__tbl)[jhash(_key, _key_len, 0) % HASH_SIZE(*__tbl)]); }) \ + +/** + * ovpn_peer_float - update remote endpoint for peer + * @peer: peer to update the remote endpoint for + * @skb: incoming packet to retrieve the source address (remote) from + */ +void ovpn_peer_float(struct ovpn_peer *peer, struct sk_buff *skb) +{ + struct hlist_nulls_head *nhead; + struct sockaddr_storage ss; + const u8 *local_ip = NULL; + struct sockaddr_in6 *sa6; + struct sockaddr_in *sa; + struct ovpn_bind *bind; + sa_family_t family; + size_t salen; + + rcu_read_lock(); + bind = rcu_dereference(peer->bind); + if (unlikely(!bind)) { + rcu_read_unlock(); + return; + } + + spin_lock_bh(&peer->lock); + if (likely(ovpn_bind_skb_src_match(bind, skb))) + goto unlock; + + family = skb_protocol_to_family(skb); + + if (bind->remote.in4.sin_family == family) + local_ip = (u8 *)&bind->local; + + switch (family) { + case AF_INET: + sa = (struct sockaddr_in *)&ss; + sa->sin_family = AF_INET; + sa->sin_addr.s_addr = ip_hdr(skb)->saddr; + sa->sin_port = udp_hdr(skb)->source; + salen = sizeof(*sa); + break; + case AF_INET6: + sa6 = (struct sockaddr_in6 *)&ss; + sa6->sin6_family = AF_INET6; + sa6->sin6_addr = ipv6_hdr(skb)->saddr; + sa6->sin6_port = udp_hdr(skb)->source; + sa6->sin6_scope_id = ipv6_iface_scope_id(&ipv6_hdr(skb)->saddr, + skb->skb_iif); + salen = sizeof(*sa6); + break; + default: + goto unlock; + } + + netdev_dbg(peer->ovpn->dev, "%s: peer %d floated to %pIScp", __func__, + peer->id, &ss); + ovpn_peer_reset_sockaddr(peer, (struct sockaddr_storage *)&ss, + local_ip); + + /* rehashing is required only in MP mode as P2P has one peer + * only and thus there is no hashtable + */ + if (peer->ovpn->mode == OVPN_MODE_MP) { + spin_lock_bh(&peer->ovpn->peers->lock); + /* remove old hashing */ + hlist_nulls_del_init_rcu(&peer->hash_entry_transp_addr); + /* re-add with new transport address */ + nhead = ovpn_get_hash_head(peer->ovpn->peers->by_transp_addr, + &ss, salen); + hlist_nulls_add_head_rcu(&peer->hash_entry_transp_addr, nhead); + spin_unlock_bh(&peer->ovpn->peers->lock); + } +unlock: + spin_unlock_bh(&peer->lock); + rcu_read_unlock(); +} + /** * ovpn_peer_release_rcu - release peer private members * @head: RCU head belonging to peer being released @@ -103,7 +225,9 @@ static void ovpn_peer_release_rcu(struct rcu_head *head) struct ovpn_peer *peer = container_of(head, struct ovpn_peer, rcu);
ovpn_crypto_state_release(&peer->crypto); + spin_lock_bh(&peer->lock); ovpn_bind_reset(peer, NULL); + spin_unlock_bh(&peer->lock);
dst_cache_destroy(&peer->dst_cache); } @@ -188,10 +312,6 @@ static struct in6_addr ovpn_nexthop_from_skb6(struct sk_buff *skb) return rt->rt6i_gateway; }
-#define ovpn_get_hash_head(_tbl, _key, _key_len) ({ \ - typeof(_tbl) *__tbl = &(_tbl); \ - (&(*__tbl)[jhash(_key, _key_len, 0) % HASH_SIZE(*__tbl)]); }) \ - /** * ovpn_peer_get_by_vpn_addr4 - retrieve peer by its VPN IPv4 address * @ovpn: the openvpn instance to search diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h index 6b66e169b33510a794f8f43dff757f0357e3e5de..ea1a014568c64d796bb18447ceb70e801bfaf3f2 100644 --- a/drivers/net/ovpn/peer.h +++ b/drivers/net/ovpn/peer.h @@ -162,4 +162,6 @@ void ovpn_peer_keepalive_work(struct work_struct *work); void ovpn_peer_update_local_endpoint(struct ovpn_peer *peer, struct sk_buff *skb);
+void ovpn_peer_float(struct ovpn_peer *peer, struct sk_buff *skb); + #endif /* _NET_OVPN_OVPNPEER_H_ */