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[net-next,v2,17/22] ovpn: add support for peer floating

Message ID 20240304150914.11444-18-antonio@openvpn.net (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series Introducing OpenVPN Data Channel Offload | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches (and no cover letter)
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 944 this patch: 944
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 1 maintainers not CCed: openvpn-devel@lists.sourceforge.net
netdev/build_clang success Errors and warnings before: 960 this patch: 960
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 960 this patch: 960
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns WARNING: line length of 87 exceeds 80 columns WARNING: line length of 94 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 4 this patch: 4
netdev/source_inline success Was 0 now: 0

Commit Message

Antonio Quartulli March 4, 2024, 3:09 p.m. UTC
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/peer.c | 92 +++++++++++++++++++++++++++++++++++++++++
 drivers/net/ovpn/peer.h |  1 +
 drivers/net/ovpn/udp.c  |  3 ++
 3 files changed, 96 insertions(+)
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Patch

diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c
index 1fcced805399..ca5cce0a0cda 100644
--- a/drivers/net/ovpn/peer.c
+++ b/drivers/net/ovpn/peer.c
@@ -139,9 +139,101 @@  struct ovpn_peer *ovpn_peer_new(struct ovpn_struct *ovpn, u32 id)
 	return ERR_PTR(ret);
 }
 
+int ovpn_peer_reset_sockaddr(struct ovpn_peer *peer, const struct sockaddr_storage *ss,
+			     const u8 *local_ip)
+{
+	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_peer_index(_tbl, _key, _key_len)		\
 	(jhash(_key, _key_len, 0) % HASH_SIZE(_tbl))	\
 
+void ovpn_peer_float(struct ovpn_peer *peer, struct sk_buff *skb)
+{
+	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;
+	u32 index;
+
+	rcu_read_lock();
+	bind = rcu_dereference(peer->bind);
+	if (unlikely(!bind))
+		goto unlock;
+
+	if (likely(ovpn_bind_skb_src_match(bind, skb)))
+		goto unlock;
+
+	family = skb_protocol_to_family(skb);
+
+	if (bind->sa.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);
+
+	spin_lock_bh(&peer->ovpn->peers.lock);
+	/* remove old hashing */
+	hlist_del_init_rcu(&peer->hash_entry_transp_addr);
+	/* re-add with new transport address */
+	index = ovpn_peer_index(peer->ovpn->peers.by_transp_addr, &ss, salen);
+	hlist_add_head_rcu(&peer->hash_entry_transp_addr,
+			   &peer->ovpn->peers.by_transp_addr[index]);
+	spin_unlock_bh(&peer->ovpn->peers.lock);
+
+unlock:
+	rcu_read_unlock();
+}
+
 static void ovpn_peer_timer_delete_all(struct ovpn_peer *peer)
 {
 	del_timer_sync(&peer->keepalive_xmit);
diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h
index 739560fc992a..c0bcb3a86ecf 100644
--- a/drivers/net/ovpn/peer.h
+++ b/drivers/net/ovpn/peer.h
@@ -166,6 +166,7 @@  struct ovpn_peer *ovpn_peer_lookup_by_src(struct ovpn_struct *ovpn, struct sk_bu
 struct ovpn_peer *ovpn_peer_lookup_id(struct ovpn_struct *ovpn, u32 peer_id);
 
 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);
 
 int ovpn_peer_reset_sockaddr(struct ovpn_peer *peer, const struct sockaddr_storage *ss,
 			     const u8 *local_ip);
diff --git a/drivers/net/ovpn/udp.c b/drivers/net/ovpn/udp.c
index addcf55abf26..693f1f6a2c0c 100644
--- a/drivers/net/ovpn/udp.c
+++ b/drivers/net/ovpn/udp.c
@@ -81,6 +81,9 @@  static int ovpn_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 					   __func__, peer_id);
 			goto drop;
 		}
+
+		/* check if this peer changed it's IP address and update state */
+		ovpn_peer_float(peer, skb);
 	}
 
 	if (!peer) {