wgengine: log connection metricsjknodt/logging

Adds counter for connection types, which aren't currently bubbled up anywhere but can be easily
in the future.

Signed-off-by: julianknodt <julianknodt@gmail.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/wgengine/userspace.go b/wgengine/userspace.go
index 4a22c888a..820e40f0e 100644
--- a/wgengine/userspace.go
+++ b/wgengine/userspace.go
@@ -119,6 +119,8 @@ type userspaceEngine struct {
 	statusBufioReader   *bufio.Reader // reusable for UAPI
 	lastStatusPollTime  mono.Time     // last time we polled the engine status
 
+	connMetrics metrics // counts for success/failure/kinds of connections.
+
 	mu                  sync.Mutex         // guards following; see lock order comment below
 	netMap              *netmap.NetworkMap // or nil
 	closing             bool               // Close was called (even if we're still closing)
@@ -133,6 +135,19 @@ type userspaceEngine struct {
 	// Lock ordering: magicsock.Conn.mu, wgLock, then mu.
 }
 
+type metrics struct {
+	// offline is the number of flows magicsock attempted to connect to which are offline.
+	offline uint32
+	// relayed is the number of flows magicsock connected thru over DERP.
+	relayed uint32
+	// direct is the number of flows connected to directly.
+	direct uint32
+	// unreachable is the number of flows which were expected to be online but could not be
+	// connected to. This is expected to be small, as there is only a brief window where flows are
+	// offline but have not yet notified control.
+	unreachable uint32
+}
+
 // InternalsGetter is implemented by Engines that can export their internals.
 type InternalsGetter interface {
 	GetInternals() (_ *tstun.Wrapper, _ *magicsock.Conn, ok bool)