diff options
| -rw-r--r-- | drivers/net/ovpn/Makefile | 2 | ||||
| -rw-r--r-- | drivers/net/ovpn/main.c | 3 | ||||
| -rw-r--r-- | drivers/net/ovpn/peer.c | 28 | ||||
| -rw-r--r-- | drivers/net/ovpn/peer.h | 6 | ||||
| -rw-r--r-- | drivers/net/ovpn/socket.c | 197 | ||||
| -rw-r--r-- | drivers/net/ovpn/socket.h | 38 | ||||
| -rw-r--r-- | drivers/net/ovpn/udp.c | 75 | ||||
| -rw-r--r-- | drivers/net/ovpn/udp.h | 19 | ||||
| -rw-r--r-- | include/uapi/linux/udp.h | 1 |
9 files changed, 362 insertions, 7 deletions
diff --git a/drivers/net/ovpn/Makefile b/drivers/net/ovpn/Makefile index 618328ae3388..164f2058ea8e 100644 --- a/drivers/net/ovpn/Makefile +++ b/drivers/net/ovpn/Makefile @@ -13,3 +13,5 @@ ovpn-y += io.o ovpn-y += netlink.o ovpn-y += netlink-gen.o ovpn-y += peer.o +ovpn-y += socket.o +ovpn-y += udp.o diff --git a/drivers/net/ovpn/main.c b/drivers/net/ovpn/main.c index 3c2b6a7df272..e9a6dc100d46 100644 --- a/drivers/net/ovpn/main.c +++ b/drivers/net/ovpn/main.c @@ -116,7 +116,8 @@ static void ovpn_dellink(struct net_device *dev, struct list_head *head) struct ovpn_priv *ovpn = netdev_priv(dev); if (ovpn->mode == OVPN_MODE_P2P) - ovpn_peer_release_p2p(ovpn, OVPN_DEL_PEER_REASON_TEARDOWN); + ovpn_peer_release_p2p(ovpn, NULL, + OVPN_DEL_PEER_REASON_TEARDOWN); unregister_netdevice_queue(dev, head); } diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c index 338069c99248..0bb6c1517184 100644 --- a/drivers/net/ovpn/peer.c +++ b/drivers/net/ovpn/peer.c @@ -16,17 +16,20 @@ #include "main.h" #include "netlink.h" #include "peer.h" +#include "socket.h" static void unlock_ovpn(struct ovpn_priv *ovpn, - struct llist_head *release_list) + struct llist_head *release_list) __releases(&ovpn->lock) { struct ovpn_peer *peer; spin_unlock_bh(&ovpn->lock); - llist_for_each_entry(peer, release_list->first, release_entry) + llist_for_each_entry(peer, release_list->first, release_entry) { + ovpn_socket_release(peer); ovpn_peer_put(peer); + } } /** @@ -394,18 +397,33 @@ int ovpn_peer_del(struct ovpn_peer *peer, enum ovpn_del_peer_reason reason) /** * ovpn_peer_release_p2p - release peer upon P2P device teardown * @ovpn: the instance being torn down + * @sk: if not NULL, release peer only if it's using this specific socket * @reason: the reason for releasing the peer */ -void ovpn_peer_release_p2p(struct ovpn_priv *ovpn, +void ovpn_peer_release_p2p(struct ovpn_priv *ovpn, struct sock *sk, enum ovpn_del_peer_reason reason) { + struct ovpn_socket *ovpn_sock; LLIST_HEAD(release_list); struct ovpn_peer *peer; spin_lock_bh(&ovpn->lock); peer = rcu_dereference_protected(ovpn->peer, lockdep_is_held(&ovpn->lock)); - if (peer) - ovpn_peer_remove(peer, reason, &release_list); + if (!peer) { + spin_unlock_bh(&ovpn->lock); + return; + } + + if (sk) { + ovpn_sock = rcu_access_pointer(peer->sock); + if (!ovpn_sock || ovpn_sock->sock->sk != sk) { + spin_unlock_bh(&ovpn->lock); + ovpn_peer_put(peer); + return; + } + } + + ovpn_peer_remove(peer, reason, &release_list); unlock_ovpn(ovpn, &release_list); } diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h index fd2e7625990a..29c9065cedcc 100644 --- a/drivers/net/ovpn/peer.h +++ b/drivers/net/ovpn/peer.h @@ -12,6 +12,8 @@ #include <net/dst_cache.h> +#include "socket.h" + /** * struct ovpn_peer - the main remote peer object * @ovpn: main openvpn instance this peer belongs to @@ -20,6 +22,7 @@ * @vpn_addrs: IP addresses assigned over the tunnel * @vpn_addrs.ipv4: IPv4 assigned to peer on the tunnel * @vpn_addrs.ipv6: IPv6 assigned to peer on the tunnel + * @sock: the socket being used to talk to this peer * @dst_cache: cache for dst_entry used to send to peer * @bind: remote peer binding * @delete_reason: why peer was deleted (i.e. timeout, transport error, ..) @@ -36,6 +39,7 @@ struct ovpn_peer { struct in_addr ipv4; struct in6_addr ipv6; } vpn_addrs; + struct ovpn_socket __rcu *sock; struct dst_cache dst_cache; struct ovpn_bind __rcu *bind; enum ovpn_del_peer_reason delete_reason; @@ -70,7 +74,7 @@ static inline void ovpn_peer_put(struct ovpn_peer *peer) struct ovpn_peer *ovpn_peer_new(struct ovpn_priv *ovpn, u32 id); int ovpn_peer_add(struct ovpn_priv *ovpn, struct ovpn_peer *peer); int ovpn_peer_del(struct ovpn_peer *peer, enum ovpn_del_peer_reason reason); -void ovpn_peer_release_p2p(struct ovpn_priv *ovpn, +void ovpn_peer_release_p2p(struct ovpn_priv *ovpn, struct sock *sk, enum ovpn_del_peer_reason reason); struct ovpn_peer *ovpn_peer_get_by_transp_addr(struct ovpn_priv *ovpn, diff --git a/drivers/net/ovpn/socket.c b/drivers/net/ovpn/socket.c new file mode 100644 index 000000000000..beec7aee35e1 --- /dev/null +++ b/drivers/net/ovpn/socket.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0 +/* OpenVPN data channel offload + * + * Copyright (C) 2020-2025 OpenVPN, Inc. + * + * Author: James Yonan <james@openvpn.net> + * Antonio Quartulli <antonio@openvpn.net> + */ + +#include <linux/net.h> +#include <linux/netdevice.h> +#include <linux/udp.h> + +#include "ovpnpriv.h" +#include "main.h" +#include "io.h" +#include "peer.h" +#include "socket.h" +#include "udp.h" + +static void ovpn_socket_release_kref(struct kref *kref) +{ + struct ovpn_socket *sock = container_of(kref, struct ovpn_socket, + refcount); + + if (sock->sock->sk->sk_protocol == IPPROTO_UDP) + ovpn_udp_socket_detach(sock); + + kfree_rcu(sock, rcu); +} + +/** + * ovpn_socket_put - decrease reference counter + * @peer: peer whose socket reference counter should be decreased + * @sock: the RCU protected peer socket + * + * This function is only used internally. Users willing to release + * references to the ovpn_socket should use ovpn_socket_release() + */ +static void ovpn_socket_put(struct ovpn_peer *peer, struct ovpn_socket *sock) +{ + kref_put(&sock->refcount, ovpn_socket_release_kref); +} + +/** + * ovpn_socket_release - release resources owned by socket user + * @peer: peer whose socket should be released + * + * This function should be invoked when the user is shutting + * down and wants to drop its link to the socket. + * + * In case of UDP, the detach routine will drop a reference to the + * ovpn netdev, pointed by the ovpn_socket. + * + * In case of TCP, releasing the socket will cause dropping + * the refcounter for the peer it is linked to, thus allowing the peer + * disappear as well. + * + * This function is expected to be invoked exactly once per peer + * + * NOTE: this function may sleep + */ +void ovpn_socket_release(struct ovpn_peer *peer) +{ + struct ovpn_socket *sock; + + might_sleep(); + + sock = rcu_replace_pointer(peer->sock, NULL, true); + /* release may be invoked after socket was detached */ + if (!sock) + return; + + /* sanity check: we should not end up here if the socket + * was already closed + */ + if (!sock->sock->sk) { + DEBUG_NET_WARN_ON_ONCE(1); + return; + } + + /* Drop the reference while holding the sock lock to avoid + * concurrent ovpn_socket_new call to mess up with a partially + * detached socket. + * + * Holding the lock ensures that a socket with refcnt 0 is fully + * detached before it can be picked by a concurrent reader. + */ + lock_sock(sock->sock->sk); + ovpn_socket_put(peer, sock); + release_sock(sock->sock->sk); + + /* align all readers with sk_user_data being NULL */ + synchronize_rcu(); +} + +static bool ovpn_socket_hold(struct ovpn_socket *sock) +{ + return kref_get_unless_zero(&sock->refcount); +} + +static int ovpn_socket_attach(struct ovpn_socket *sock, struct ovpn_peer *peer) +{ + if (sock->sock->sk->sk_protocol == IPPROTO_UDP) + return ovpn_udp_socket_attach(sock, peer->ovpn); + + return -EOPNOTSUPP; +} + +/** + * ovpn_socket_new - create a new socket and initialize it + * @sock: the kernel socket to embed + * @peer: the peer reachable via this socket + * + * Return: an openvpn socket on success or a negative error code otherwise + */ +struct ovpn_socket *ovpn_socket_new(struct socket *sock, struct ovpn_peer *peer) +{ + struct ovpn_socket *ovpn_sock; + int ret; + + lock_sock(sock->sk); + + /* a TCP socket can only be owned by a single peer, therefore there + * can't be any other user + */ + if (sock->sk->sk_protocol == IPPROTO_TCP && sock->sk->sk_user_data) { + ovpn_sock = ERR_PTR(-EBUSY); + goto sock_release; + } + + /* a UDP socket can be shared across multiple peers, but we must make + * sure it is not owned by something else + */ + if (sock->sk->sk_protocol == IPPROTO_UDP) { + u8 type = READ_ONCE(udp_sk(sock->sk)->encap_type); + + /* socket owned by other encapsulation module */ + if (type && type != UDP_ENCAP_OVPNINUDP) { + ovpn_sock = ERR_PTR(-EBUSY); + goto sock_release; + } + + rcu_read_lock(); + ovpn_sock = rcu_dereference_sk_user_data(sock->sk); + if (ovpn_sock) { + /* socket owned by another ovpn instance, we can't use it */ + if (ovpn_sock->ovpn != peer->ovpn) { + ovpn_sock = ERR_PTR(-EBUSY); + rcu_read_unlock(); + goto sock_release; + } + + /* this socket is already owned by this instance, + * therefore we can increase the refcounter and + * use it as expected + */ + if (WARN_ON(!ovpn_socket_hold(ovpn_sock))) { + /* this should never happen because setting + * the refcnt to 0 and detaching the socket + * is expected to be atomic + */ + ovpn_sock = ERR_PTR(-EAGAIN); + rcu_read_unlock(); + goto sock_release; + } + + rcu_read_unlock(); + goto sock_release; + } + rcu_read_unlock(); + } + + /* socket is not owned: attach to this ovpn instance */ + + ovpn_sock = kzalloc(sizeof(*ovpn_sock), GFP_KERNEL); + if (!ovpn_sock) { + ovpn_sock = ERR_PTR(-ENOMEM); + goto sock_release; + } + + ovpn_sock->ovpn = peer->ovpn; + ovpn_sock->sock = sock; + kref_init(&ovpn_sock->refcount); + + ret = ovpn_socket_attach(ovpn_sock, peer); + if (ret < 0) { + kfree(ovpn_sock); + ovpn_sock = ERR_PTR(ret); + goto sock_release; + } + + rcu_assign_sk_user_data(sock->sk, ovpn_sock); +sock_release: + release_sock(sock->sk); + return ovpn_sock; +} diff --git a/drivers/net/ovpn/socket.h b/drivers/net/ovpn/socket.h new file mode 100644 index 000000000000..ade8c94619d7 --- /dev/null +++ b/drivers/net/ovpn/socket.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* OpenVPN data channel offload + * + * Copyright (C) 2020-2025 OpenVPN, Inc. + * + * Author: James Yonan <james@openvpn.net> + * Antonio Quartulli <antonio@openvpn.net> + */ + +#ifndef _NET_OVPN_SOCK_H_ +#define _NET_OVPN_SOCK_H_ + +#include <linux/net.h> +#include <linux/kref.h> +#include <net/sock.h> + +struct ovpn_priv; +struct ovpn_peer; + +/** + * struct ovpn_socket - a kernel socket referenced in the ovpn code + * @ovpn: ovpn instance owning this socket (UDP only) + * @sock: the low level sock object + * @refcount: amount of contexts currently referencing this object + * @rcu: member used to schedule RCU destructor callback + */ +struct ovpn_socket { + struct ovpn_priv *ovpn; + struct socket *sock; + struct kref refcount; + struct rcu_head rcu; +}; + +struct ovpn_socket *ovpn_socket_new(struct socket *sock, + struct ovpn_peer *peer); +void ovpn_socket_release(struct ovpn_peer *peer); + +#endif /* _NET_OVPN_SOCK_H_ */ diff --git a/drivers/net/ovpn/udp.c b/drivers/net/ovpn/udp.c new file mode 100644 index 000000000000..91970e66a434 --- /dev/null +++ b/drivers/net/ovpn/udp.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0 +/* OpenVPN data channel offload + * + * Copyright (C) 2019-2025 OpenVPN, Inc. + * + * Author: Antonio Quartulli <antonio@openvpn.net> + */ + +#include <linux/netdevice.h> +#include <linux/socket.h> +#include <linux/udp.h> +#include <net/udp.h> + +#include "ovpnpriv.h" +#include "main.h" +#include "socket.h" +#include "udp.h" + +/** + * ovpn_udp_socket_attach - set udp-tunnel CBs on socket and link it to ovpn + * @ovpn_sock: socket to configure + * @ovpn: the openvp instance to link + * + * After invoking this function, the sock will be controlled by ovpn so that + * any incoming packet may be processed by ovpn first. + * + * Return: 0 on success or a negative error code otherwise + */ +int ovpn_udp_socket_attach(struct ovpn_socket *ovpn_sock, + struct ovpn_priv *ovpn) +{ + struct socket *sock = ovpn_sock->sock; + struct ovpn_socket *old_data; + int ret = 0; + + /* make sure no pre-existing encapsulation handler exists */ + rcu_read_lock(); + old_data = rcu_dereference_sk_user_data(sock->sk); + if (!old_data) { + /* socket is currently unused - we can take it */ + rcu_read_unlock(); + return 0; + } + + /* socket is in use. We need to understand if it's owned by this ovpn + * instance or by something else. + * In the former case, we can increase the refcounter and happily + * use it, because the same UDP socket is expected to be shared among + * different peers. + * + * Unlikely TCP, a single UDP socket can be used to talk to many remote + * hosts and therefore openvpn instantiates one only for all its peers + */ + if ((READ_ONCE(udp_sk(sock->sk)->encap_type) == UDP_ENCAP_OVPNINUDP) && + old_data->ovpn == ovpn) { + netdev_dbg(ovpn->dev, + "provided socket already owned by this interface\n"); + ret = -EALREADY; + } else { + netdev_dbg(ovpn->dev, + "provided socket already taken by other user\n"); + ret = -EBUSY; + } + rcu_read_unlock(); + + return ret; +} + +/** + * ovpn_udp_socket_detach - clean udp-tunnel status for this socket + * @ovpn_sock: the socket to clean + */ +void ovpn_udp_socket_detach(struct ovpn_socket *ovpn_sock) +{ +} diff --git a/drivers/net/ovpn/udp.h b/drivers/net/ovpn/udp.h new file mode 100644 index 000000000000..1c8fb6fe402d --- /dev/null +++ b/drivers/net/ovpn/udp.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* OpenVPN data channel offload + * + * Copyright (C) 2019-2025 OpenVPN, Inc. + * + * Author: Antonio Quartulli <antonio@openvpn.net> + */ + +#ifndef _NET_OVPN_UDP_H_ +#define _NET_OVPN_UDP_H_ + +struct ovpn_priv; +struct socket; + +int ovpn_udp_socket_attach(struct ovpn_socket *ovpn_sock, + struct ovpn_priv *ovpn); +void ovpn_udp_socket_detach(struct ovpn_socket *ovpn_sock); + +#endif /* _NET_OVPN_UDP_H_ */ diff --git a/include/uapi/linux/udp.h b/include/uapi/linux/udp.h index d85d671deed3..edca3e430305 100644 --- a/include/uapi/linux/udp.h +++ b/include/uapi/linux/udp.h @@ -43,5 +43,6 @@ struct udphdr { #define UDP_ENCAP_GTP1U 5 /* 3GPP TS 29.060 */ #define UDP_ENCAP_RXRPC 6 #define TCP_ENCAP_ESPINTCP 7 /* Yikes, this is really xfrm encap types. */ +#define UDP_ENCAP_OVPNINUDP 8 /* OpenVPN traffic */ #endif /* _UAPI_LINUX_UDP_H */ |