[PATCH net-next v9 16/23] ovpn: add support for updating local UDP endpoint

Antonio Quartulli
2024-10-16T01:04:15Z

In case of UDP links, the local endpoint used to communicate with a
given peer may change without a connection restart.

Add support for learning the new address in case of change.

Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
---
drivers/net/ovpn/peer.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
drivers/net/ovpn/peer.h | 3 +++
2 files changed, 48 insertions(+)

diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c
index fa1883d12dfd6ce3e2ad1f9835f15aa7db5c8290..f3b20a561d614da98a8bee80272095b15bc6650d 100644
--- a/drivers/net/ovpn/peer.c
+++ b/drivers/net/ovpn/peer.c
@@ -416,6 +416,51 @@ struct ovpn_peer *ovpn_peer_get_by_id(struct ovpn_struct *ovpn, u32 peer_id)
return peer;
}

+/**
+ * ovpn_peer_update_local_endpoint - update local endpoint for peer
+ * @peer: peer to update the endpoint for
+ * @skb: incoming packet to retrieve the destination address (local) from
+ */
+void ovpn_peer_update_local_endpoint(struct ovpn_peer *peer,
+ struct sk_buff *skb)
+{
+ struct ovpn_bind *bind;
+
+ rcu_read_lock();
+ bind = rcu_dereference(peer->bind);
+ if (unlikely(!bind))
+ goto unlock;
+
+ spin_lock_bh(&peer->lock);
+ switch (skb_protocol_to_family(skb)) {
+ case AF_INET:
+ if (unlikely(bind->local.ipv4.s_addr != ip_hdr(skb)->daddr)) {
+ netdev_dbg(peer->ovpn->dev,
+ "%s: learning local IPv4 for peer %d (%pI4 -> %pI4)\n",
+ __func__, peer->id, &bind->local.ipv4.s_addr,
+ &ip_hdr(skb)->daddr);
+ bind->local.ipv4.s_addr = ip_hdr(skb)->daddr;
+ }
+ break;
+ case AF_INET6:
+ if (unlikely(!ipv6_addr_equal(&bind->local.ipv6,
+ &ipv6_hdr(skb)->daddr))) {
+ netdev_dbg(peer->ovpn->dev,
+ "%s: learning local IPv6 for peer %d (%pI6c -> %pI6c\n",
+ __func__, peer->id, &bind->local.ipv6,
+ &ipv6_hdr(skb)->daddr);
+ bind->local.ipv6 = ipv6_hdr(skb)->daddr;
+ }
+ break;
+ default:
+ break;
+ }
+ spin_unlock_bh(&peer->lock);
+
+unlock:
+ rcu_read_unlock();
+}
+
/**
* ovpn_peer_get_by_dst - Lookup peer to send skb to
* @ovpn: the private data representing the current VPN session
diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h
index 952927ae78a3ab753aaf2c6cc6f77121bdac34be..1a8638d266b11a4a80ee2f088394d47a7798c3af 100644
--- a/drivers/net/ovpn/peer.h
+++ b/drivers/net/ovpn/peer.h
@@ -152,4 +152,7 @@ bool ovpn_peer_check_by_src(struct ovpn_struct *ovpn, struct sk_buff *skb,
void ovpn_peer_keepalive_set(struct ovpn_peer *peer, u32 interval, u32 timeout);
void ovpn_peer_keepalive_work(struct work_struct *work);

+void ovpn_peer_update_local_endpoint(struct ovpn_peer *peer,
+ struct sk_buff *skb);
+
#endif /* _NET_OVPN_OVPNPEER_H_ */

--
2.45.2