Per NIC NetworkEndpoint statistics

To facilitate the debugging of multi-homed setup, track Network
protocols statistics for each endpoint. Note that the original
stack-wide stats still exist.

A new type of statistic counter is introduced, which track two
versions of a stat at the same time. This lets a network endpoint
increment both the local stat and the stack-wide stat at the same
time.

Fixes #4605

PiperOrigin-RevId: 352663276

1 files changed, 20 insertions, 0 deletions

diff --git a/pkg/tcpip/stack/registration.go b/pkg/tcpip/stack/registration.go
index a73bc7007..34c122728 100644
--- a/pkg/tcpip/stack/registration.go
+++ b/pkg/tcpip/stack/registration.go
@@ -597,6 +597,26 @@ type NetworkEndpoint interface {
 	// NetworkProtocolNumber returns the tcpip.NetworkProtocolNumber for
 	// this endpoint.
 	NetworkProtocolNumber() tcpip.NetworkProtocolNumber
+
+	// Stats returns a reference to the network endpoint stats.
+	Stats() NetworkEndpointStats
+}
+
+// NetworkEndpointStats is the interface implemented by each network endpoint
+// stats struct.
+type NetworkEndpointStats interface {
+	// IsNetworkEndpointStats is an empty method to implement the
+	// NetworkEndpointStats marker interface.
+	IsNetworkEndpointStats()
+}
+
+// IPNetworkEndpointStats is a NetworkEndpointStats that tracks IP-related
+// statistics.
+type IPNetworkEndpointStats interface {
+	NetworkEndpointStats
+
+	// IPStats returns the IP statistics of a network endpoint.
+	IPStats() *tcpip.IPStats
 }
 
 // ForwardingNetworkProtocol is a NetworkProtocol that may forward packets.