From a97a07d79c847d0b30c61a2589e7bde62f25d603 Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@meshlink.io>
Date: Mon, 27 Jan 2020 15:07:35 +0100
Subject: [PATCH] Only let mesh->self be reachable when the mesh is started.

This ensures meshlink_node_get_reachability(mesh->self) returns true only
if the mesh has been started. It also handles reachability of self in
graph.c just like any other node. This means there will now also be a
node status callback generated when the mesh is started and stopped.
---
 src/graph.c     |  2 +-
 src/meshlink.c  | 16 +++++++++-------
 src/net_setup.c |  3 ---
 test/basic.c    | 30 ++++++++++++++++++++++++++----
 4 files changed, 36 insertions(+), 15 deletions(-)

diff --git a/src/graph.c b/src/graph.c
index d70279c2..e6212116 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -72,7 +72,7 @@ static void sssp_bfs(meshlink_handle_t *mesh) {
 
 	/* Begin with mesh->self */
 
-	mesh->self->status.visited = true;
+	mesh->self->status.visited = mesh->threadstarted;
 	mesh->self->nexthop = mesh->self;
 	mesh->self->prevedge = NULL;
 	mesh->self->distance = 0;
diff --git a/src/meshlink.c b/src/meshlink.c
index 2d4c2e1f..2309d775 100644
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -37,6 +37,7 @@
 #include "ed25519/sha512.h"
 #include "discovery.h"
 #include "devtools.h"
+#include "graph.h"
 
 #ifndef MSG_NOSIGNAL
 #define MSG_NOSIGNAL 0
@@ -1527,8 +1528,9 @@ bool meshlink_start(meshlink_handle_t *mesh) {
 
 	pthread_cond_wait(&mesh->cond, &mesh->mutex);
 	mesh->threadstarted = true;
-	mesh->self->last_reachable = time(NULL);
-	mesh->self->status.dirty = true;
+
+	// Ensure we are considered reachable
+	graph(mesh);
 
 	pthread_mutex_unlock(&mesh->mutex);
 	return true;
@@ -1543,11 +1545,6 @@ void meshlink_stop(meshlink_handle_t *mesh) {
 	pthread_mutex_lock(&mesh->mutex);
 	logger(mesh, MESHLINK_DEBUG, "meshlink_stop called\n");
 
-	if(mesh->self) {
-		mesh->self->last_unreachable = time(NULL);
-		mesh->self->status.dirty = true;
-	}
-
 	// Shut down the main thread
 	event_loop_stop(&mesh->loop);
 
@@ -1587,6 +1584,11 @@ void meshlink_stop(meshlink_handle_t *mesh) {
 
 	exit_outgoings(mesh);
 
+	// Ensure we are considered unreachable
+	if(mesh->nodes) {
+		graph(mesh);
+	}
+
 	// Try to write out any changed node config files, ignore errors at this point.
 	if(mesh->nodes) {
 		for splay_each(node_t, n, mesh->nodes) {
diff --git a/src/net_setup.c b/src/net_setup.c
index 8baff8b8..1b091db0 100644
--- a/src/net_setup.c
+++ b/src/net_setup.c
@@ -412,12 +412,9 @@ bool setup_myself(meshlink_handle_t *mesh) {
 	/* Done */
 
 	mesh->self->nexthop = mesh->self;
-	mesh->self->status.reachable = true;
 
 	node_add(mesh, mesh->self);
 
-	graph(mesh);
-
 	if(!config_scan_all(mesh, "current", "hosts", load_node, NULL)) {
 		logger(mesh, MESHLINK_WARNING, "Could not scan all host config files");
 	}
diff --git a/test/basic.c b/test/basic.c
index 46f86960..bf8ff772 100644
--- a/test/basic.c
+++ b/test/basic.c
@@ -37,18 +37,31 @@ int main() {
 	assert(self);
 	assert(!strcmp(self->name, "foo"));
 
-	// Check that we are reachable.
+	// Check that we are not reachable.
 
-	assert(meshlink_get_node_reachability(mesh, self, NULL, NULL));
+	time_t last_reachable;
+	time_t last_unreachable;
+	assert(!meshlink_get_node_reachability(mesh, self, &last_reachable, &last_unreachable));
+	assert(!last_reachable);
+	assert(!last_unreachable);
 
 	// Start and stop the mesh.
 
 	assert(meshlink_start(mesh));
+
+	// Check that we are now reachable
+
+	assert(meshlink_get_node_reachability(mesh, self, &last_reachable, &last_unreachable));
+	assert(last_reachable);
+	assert(!last_unreachable);
+
 	meshlink_stop(mesh);
 
-	// Check that we are still reachable.
+	// Check that we are no longer reachable.
 
-	assert(meshlink_get_node_reachability(mesh, self, NULL, NULL));
+	assert(!meshlink_get_node_reachability(mesh, self, &last_reachable, &last_unreachable));
+	assert(last_reachable);
+	assert(last_unreachable);
 
 	// Make sure we can start and stop the mesh again.
 
@@ -63,6 +76,15 @@ int main() {
 	mesh = meshlink_open("basic_conf", "bar", "basic", DEV_CLASS_BACKBONE);
 	assert(mesh);
 
+	self = meshlink_get_self(mesh);
+	assert(self);
+
+	// Check that we remembered we were reachable
+
+	assert(!meshlink_get_node_reachability(mesh, self, &last_reachable, &last_unreachable));
+	assert(last_reachable);
+	assert(last_unreachable);
+
 	// Check that the name is ignored now, and that we still are "foo".
 
 	assert(!meshlink_get_node(mesh, "bar"));
-- 
2.39.5