From c4deb6c20dceb73c0ac6baa2eb901434584e6191 Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@meshlink.io>
Date: Mon, 7 Sep 2020 21:12:28 +0200
Subject: [PATCH] Use the canonical address exclusively for making outgoing
 meta-connections.

If we have a node's canonical address, we now always use that as a source
for addresses for outgoing meta-connection attempts. This commit also adds
the function meshlink_clear_canonical_address() to ensure the canonical
address can be removed if it is no longer valid.
---
 src/meshlink++.h | 12 ++++++++++++
 src/meshlink.c   | 24 ++++++++++++++++++++++++
 src/meshlink.h   | 13 +++++++++++++
 src/meshlink.sym |  1 +
 src/net_socket.c |  2 +-
 5 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/src/meshlink++.h b/src/meshlink++.h
index e0a51066..183544ac 100644
--- a/src/meshlink++.h
+++ b/src/meshlink++.h
@@ -515,6 +515,18 @@ public:
 		return meshlink_set_canonical_address(handle, node, address, port);
 	}
 
+	/// Clear the canonical Address for a node.
+	/** This function clears the canonical Address for a node.
+	 *
+	 *  @param mesh         A handle which represents an instance of MeshLink.
+	 *  @param node         A pointer to a struct meshlink_node describing the node.
+	 *
+	 *  @return             This function returns true if the address was removed, false otherwise.
+	 */
+	bool clear_canonical_address(node *node) {
+		return meshlink_clear_canonical_address(handle, node);
+	}
+
 	/// Add an invitation address for the local node.
 	/** This function adds an address for the local node, which will be used only for invitation URLs.
 	 *  This address is not stored permanently.
diff --git a/src/meshlink.c b/src/meshlink.c
index 7492c46b..56da2a04 100644
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -2603,6 +2603,30 @@ bool meshlink_set_canonical_address(meshlink_handle_t *mesh, meshlink_node_t *no
 	return config_sync(mesh, "current");
 }
 
+bool meshlink_clear_canonical_address(meshlink_handle_t *mesh, meshlink_node_t *node) {
+	if(!mesh || !node) {
+		meshlink_errno = MESHLINK_EINVAL;
+		return false;
+	}
+
+	if(pthread_mutex_lock(&mesh->mutex) != 0) {
+		abort();
+	}
+
+	node_t *n = (node_t *)node;
+	free(n->canonical_address);
+	n->canonical_address = NULL;
+
+	if(!node_write_config(mesh, n)) {
+		pthread_mutex_unlock(&mesh->mutex);
+		return false;
+	}
+
+	pthread_mutex_unlock(&mesh->mutex);
+
+	return config_sync(mesh, "current");
+}
+
 bool meshlink_add_invitation_address(struct meshlink_handle *mesh, const char *address, const char *port) {
 	if(!mesh || !address) {
 		meshlink_errno = MESHLINK_EINVAL;
diff --git a/src/meshlink.h b/src/meshlink.h
index 3a23eb08..738f8647 100644
--- a/src/meshlink.h
+++ b/src/meshlink.h
@@ -801,6 +801,8 @@ bool meshlink_verify(struct meshlink_handle *mesh, struct meshlink_node *source,
  *
  *  If a canonical Address is set for the local node,
  *  it will be used for the hostname part of generated invitation URLs.
+ *  If a canonical Address is set for a remote node,
+ *  it is used exclusively for creating outgoing connections to that node.
  *
  *  \memberof meshlink_node
  *  @param mesh         A handle which represents an instance of MeshLink.
@@ -813,6 +815,17 @@ bool meshlink_verify(struct meshlink_handle *mesh, struct meshlink_node *source,
  */
 bool meshlink_set_canonical_address(struct meshlink_handle *mesh, struct meshlink_node *node, const char *address, const char *port) __attribute__((__warn_unused_result__));
 
+/// Clear the canonical Address for a node.
+/** This function clears the canonical Address for a node.
+ *
+ *  \memberof meshlink_node
+ *  @param mesh         A handle which represents an instance of MeshLink.
+ *  @param node         A pointer to a struct meshlink_node describing the node.
+ *
+ *  @return             This function returns true if the address was removed, false otherwise.
+ */
+bool meshlink_clear_canonical_address(struct meshlink_handle *mesh, struct meshlink_node *node) __attribute__((__warn_unused_result__));
+
 /// Add an invitation address for the local node.
 /** This function adds an address for the local node, which will be used only for invitation URLs.
  *  This address is not stored permanently.
diff --git a/src/meshlink.sym b/src/meshlink.sym
index ba79ce3f..08dff729 100644
--- a/src/meshlink.sym
+++ b/src/meshlink.sym
@@ -26,6 +26,7 @@ meshlink_channel_open
 meshlink_channel_open_ex
 meshlink_channel_send
 meshlink_channel_shutdown
+meshlink_clear_canonical_address
 meshlink_clear_invitation_addresses
 meshlink_close
 meshlink_destroy
diff --git a/src/net_socket.c b/src/net_socket.c
index 7ac6dbbd..d8462372 100644
--- a/src/net_socket.c
+++ b/src/net_socket.c
@@ -320,7 +320,7 @@ static bool get_next_outgoing_address(meshlink_handle_t *mesh, outgoing_t *outgo
 
 		outgoing->ai = NULL;
 		outgoing->aip = NULL;
-		outgoing->state = OUTGOING_RECENT;
+		outgoing->state = OUTGOING_END;
 	}
 
 	if(outgoing->state == OUTGOING_RECENT) {
-- 
2.39.2