[PATCH net-next v3 14/24] ovpn: implement multi-peer support

Antonio Quartulli
2024-05-06T01:15:51Z

With this change an ovpn instance will be able to stay connected to
multiple remote endpoints.

This functionality is strictly required when running ovpn on an
OpenVPN server.

Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
---
drivers/net/ovpn/io.c | 1 +
drivers/net/ovpn/main.c | 8 +-
drivers/net/ovpn/ovpnstruct.h | 10 +++
drivers/net/ovpn/peer.c | 149 ++++++++++++++++++++++++++++++++++
drivers/net/ovpn/peer.h | 14 ++++
5 files changed, 181 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ovpn/io.c b/drivers/net/ovpn/io.c
index 49efcfff963c..8ccf2700a370 100644
--- a/drivers/net/ovpn/io.c
+++ b/drivers/net/ovpn/io.c
@@ -36,6 +36,7 @@ int ovpn_struct_init(struct net_device *dev)
return err;

spin_lock_init(&ovpn->lock);
+ spin_lock_init(&ovpn->peers.lock);

ovpn->crypto_wq = alloc_workqueue("ovpn-crypto-wq-%s",
WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 0,
diff --git a/drivers/net/ovpn/main.c b/drivers/net/ovpn/main.c
index a04d6e55a473..d6ba91c6571f 100644
--- a/drivers/net/ovpn/main.c
+++ b/drivers/net/ovpn/main.c
@@ -176,8 +176,14 @@ void ovpn_iface_destruct(struct ovpn_struct *ovpn)

ovpn->registered = false;

- if (ovpn->mode == OVPN_MODE_P2P)
+ switch (ovpn->mode) {
+ case OVPN_MODE_P2P:
ovpn_peer_release_p2p(ovpn);
+ break;
+ default:
+ ovpn_peers_free(ovpn);
+ break;
+ }

unregister_netdevice(ovpn->dev);
synchronize_net();
diff --git a/drivers/net/ovpn/ovpnstruct.h b/drivers/net/ovpn/ovpnstruct.h
index 7414c2459fb9..58166fdeac63 100644
--- a/drivers/net/ovpn/ovpnstruct.h
+++ b/drivers/net/ovpn/ovpnstruct.h
@@ -21,6 +21,10 @@
* @crypto_wq: used to schedule crypto work that may sleep during TX/RX
* @event_wq: used to schedule generic events that may sleep and that need to be
* performed outside of softirq context
+ * @peers.by_id: table of peers index by ID
+ * @peers.by_transp_addr: table of peers indexed by transport address
+ * @peers.by_vpn_addr: table of peers indexed by VPN IP address
+ * @peers.lock: protects writes to peers tables
* @peer: in P2P mode, this is the only remote peer
* @dev_list: entry for the module wide device list
*/
@@ -31,6 +35,12 @@ struct ovpn_struct {
spinlock_t lock; /* protect writing to the ovpn_struct object */
struct workqueue_struct *crypto_wq;
struct workqueue_struct *events_wq;
+ struct {
+ DECLARE_HASHTABLE(by_id, 12);
+ DECLARE_HASHTABLE(by_transp_addr, 12);
+ DECLARE_HASHTABLE(by_vpn_addr, 12);
+ spinlock_t lock; /* protects writes to peers tables */
+ } peers;
struct ovpn_peer __rcu *peer;
struct list_head dev_list;
};
diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c
index 99a2ae42a332..38a89595dade 100644
--- a/drivers/net/ovpn/peer.c
+++ b/drivers/net/ovpn/peer.c
@@ -9,6 +9,7 @@

#include <linux/skbuff.h>
#include <linux/list.h>
+#include <linux/hashtable.h>
#include <linux/workqueue.h>

#include "ovpnstruct.h"
@@ -361,6 +362,91 @@ struct ovpn_peer *ovpn_peer_get_by_src(struct ovpn_struct *ovpn,
return peer;
}

+/**
+ * ovpn_peer_add_mp - add per to related tables in a MP instance
+ * @ovpn: the instance to add the peer to
+ * @peer: the peer to add
+ *
+ * Return: 0 on success or a negative error code otherwise
+ */
+static int ovpn_peer_add_mp(struct ovpn_struct *ovpn, struct ovpn_peer *peer)
+{
+ struct sockaddr_storage sa = { 0 };
+ struct sockaddr_in6 *sa6;
+ struct sockaddr_in *sa4;
+ struct ovpn_bind *bind;
+ struct ovpn_peer *tmp;
+ size_t salen;
+ int ret = 0;
+ u32 index;
+
+ spin_lock_bh(&ovpn->peers.lock);
+ /* do not add duplicates */
+ tmp = ovpn_peer_get_by_id(ovpn, peer->id);
+ if (tmp) {
+ ovpn_peer_put(tmp);
+ ret = -EEXIST;
+ goto unlock;
+ }
+
+ hlist_del_init_rcu(&peer->hash_entry_transp_addr);
+ bind = rcu_dereference_protected(peer->bind, true);
+ /* peers connected via TCP have bind == NULL */
+ if (bind) {
+ switch (bind->sa.in4.sin_family) {
+ case AF_INET:
+ sa4 = (struct sockaddr_in *)&sa;
+
+ sa4->sin_family = AF_INET;
+ sa4->sin_addr.s_addr = bind->sa.in4.sin_addr.s_addr;
+ sa4->sin_port = bind->sa.in4.sin_port;
+ salen = sizeof(*sa4);
+ break;
+ case AF_INET6:
+ sa6 = (struct sockaddr_in6 *)&sa;
+
+ sa6->sin6_family = AF_INET6;
+ sa6->sin6_addr = bind->sa.in6.sin6_addr;
+ sa6->sin6_port = bind->sa.in6.sin6_port;
+ salen = sizeof(*sa6);
+ break;
+ default:
+ ret = -EPROTONOSUPPORT;
+ goto unlock;
+ }
+
+ index = ovpn_peer_index(ovpn->peers.by_transp_addr, &sa, salen);
+ hlist_add_head_rcu(&peer->hash_entry_transp_addr,
+ &ovpn->peers.by_transp_addr[index]);
+ }
+
+ index = ovpn_peer_index(ovpn->peers.by_id, &peer->id, sizeof(peer->id));
+ hlist_add_head_rcu(&peer->hash_entry_id, &ovpn->peers.by_id[index]);
+
+ if (peer->vpn_addrs.ipv4.s_addr != htonl(INADDR_ANY)) {
+ index = ovpn_peer_index(ovpn->peers.by_vpn_addr,
+ &peer->vpn_addrs.ipv4,
+ sizeof(peer->vpn_addrs.ipv4));
+ hlist_add_head_rcu(&peer->hash_entry_addr4,
+ &ovpn->peers.by_vpn_addr[index]);
+ }
+
+ hlist_del_init_rcu(&peer->hash_entry_addr6);
+ if (memcmp(&peer->vpn_addrs.ipv6, &in6addr_any,
+ sizeof(peer->vpn_addrs.ipv6))) {
+ index = ovpn_peer_index(ovpn->peers.by_vpn_addr,
+ &peer->vpn_addrs.ipv6,
+ sizeof(peer->vpn_addrs.ipv6));
+ hlist_add_head_rcu(&peer->hash_entry_addr6,
+ &ovpn->peers.by_vpn_addr[index]);
+ }
+
+unlock:
+ spin_unlock_bh(&ovpn->peers.lock);
+
+ return ret;
+}
+
/**
* ovpn_peer_add_p2p - add per to related tables in a P2P instance
* @ovpn: the instance to add the peer to
@@ -391,6 +477,8 @@ static int ovpn_peer_add_p2p(struct ovpn_struct *ovpn, struct ovpn_peer *peer)
int ovpn_peer_add(struct ovpn_struct *ovpn, struct ovpn_peer *peer)
{
switch (ovpn->mode) {
+ case OVPN_MODE_MP:
+ return ovpn_peer_add_mp(ovpn, peer);
case OVPN_MODE_P2P:
return ovpn_peer_add_p2p(ovpn, peer);
default:
@@ -398,6 +486,53 @@ int ovpn_peer_add(struct ovpn_struct *ovpn, struct ovpn_peer *peer)
}
}

+/**
+ * ovpn_peer_unhash - remove peer reference from all hashtables
+ * @peer: the peer to remove
+ * @reason: the delete reason to attach to the peer
+ */
+static void ovpn_peer_unhash(struct ovpn_peer *peer,
+ enum ovpn_del_peer_reason reason)
+{
+ hlist_del_init_rcu(&peer->hash_entry_id);
+ hlist_del_init_rcu(&peer->hash_entry_addr4);
+ hlist_del_init_rcu(&peer->hash_entry_addr6);
+ hlist_del_init_rcu(&peer->hash_entry_transp_addr);
+
+ ovpn_peer_put(peer);
+ peer->delete_reason = reason;
+}
+
+/**
+ * ovpn_peer_del_mp - delete peer from related tables in a MP instance
+ * @peer: the peer to delete
+ * @reason: reason why the peer was deleted (sent to userspace)
+ *
+ * Return: 0 on success or a negative error code otherwise
+ */
+static int ovpn_peer_del_mp(struct ovpn_peer *peer,
+ enum ovpn_del_peer_reason reason)
+{
+ struct ovpn_peer *tmp;
+ int ret = 0;
+
+ spin_lock_bh(&peer->ovpn->peers.lock);
+ tmp = ovpn_peer_get_by_id(peer->ovpn, peer->id);
+ if (tmp != peer) {
+ ret = -ENOENT;
+ goto unlock;
+ }
+ ovpn_peer_unhash(peer, reason);
+
+unlock:
+ spin_unlock_bh(&peer->ovpn->peers.lock);
+
+ if (tmp)
+ ovpn_peer_put(tmp);
+
+ return ret;
+}
+
/**
* ovpn_peer_del_p2p - delete peer from related tables in a P2P instance
* @peer: the peer to delete
@@ -444,9 +579,23 @@ void ovpn_peer_release_p2p(struct ovpn_struct *ovpn)
int ovpn_peer_del(struct ovpn_peer *peer, enum ovpn_del_peer_reason reason)
{
switch (peer->ovpn->mode) {
+ case OVPN_MODE_MP:
+ return ovpn_peer_del_mp(peer, reason);
case OVPN_MODE_P2P:
return ovpn_peer_del_p2p(peer, reason);
default:
return -EOPNOTSUPP;
}
}
+
+void ovpn_peers_free(struct ovpn_struct *ovpn)
+{
+ struct hlist_node *tmp;
+ struct ovpn_peer *peer;
+ int bkt;
+
+ spin_lock_bh(&ovpn->peers.lock);
+ hash_for_each_safe(ovpn->peers.by_id, bkt, tmp, peer, hash_entry_id)
+ ovpn_peer_unhash(peer, OVPN_DEL_PEER_REASON_TEARDOWN);
+ spin_unlock_bh(&ovpn->peers.lock);
+}
diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h
index ac4907705d98..10f4153f7c8f 100644
--- a/drivers/net/ovpn/peer.h
+++ b/drivers/net/ovpn/peer.h
@@ -26,6 +26,10 @@
* @id: unique identifier
* @vpn_addrs.ipv4: IPv4 assigned to peer on the tunnel
* @vpn_addrs.ipv6: IPv6 assigned to peer on the tunnel
+ * @hash_entry_id: entry in the peer ID hashtable
+ * @hash_entry_addr4: entry in the peer IPv4 hashtable
+ * @hash_entry_addr6: entry in the peer IPv6 hashtable
+ * @hash_entry_transp_addr: entry in the peer transport address hashtable
* @encrypt_work: work used to process outgoing packets
* @decrypt_work: work used to process incoming packets
* @tx_ring: queue of outgoing poackets to this peer
@@ -62,6 +66,10 @@ struct ovpn_peer {
struct in_addr ipv4;
struct in6_addr ipv6;
} vpn_addrs;
+ struct hlist_node hash_entry_id;
+ struct hlist_node hash_entry_addr4;
+ struct hlist_node hash_entry_addr6;
+ struct hlist_node hash_entry_transp_addr;
struct work_struct encrypt_work;
struct work_struct decrypt_work;
struct ptr_ring tx_ring;
@@ -208,4 +216,10 @@ struct ovpn_peer *ovpn_peer_get_by_dst(struct ovpn_struct *ovpn,
struct ovpn_peer *ovpn_peer_get_by_src(struct ovpn_struct *ovpn,
struct sk_buff *skb);

+/**
+ * ovpn_peers_free - free all peers in the instance
+ * @ovpn: the instance whose peers should be released
+ */
+void ovpn_peers_free(struct ovpn_struct *ovpn);
+
#endif /* _NET_OVPN_OVPNPEER_H_ */
--
2.43.2