wgengine: disambiguate Reconfig logging paths

go.sum

@@ -84,6 +84,8 @@ github.com/tailscale/winipcfg-go v0.0.0-20200413171540-609dcf2df55f h1:uFj5bslHs
 github.com/tailscale/winipcfg-go v0.0.0-20200413171540-609dcf2df55f/go.mod h1:x880GWw5fvrl2DVTQ04ttXQD4DuppTt1Yz6wLibbjNE=
 github.com/tailscale/wireguard-go v0.0.0-20200515231107-62868271d710 h1:I6aq3tOYbZob9uwhGpr7R266qTeU9PFqS6NnpfCqEzo=
 github.com/tailscale/wireguard-go v0.0.0-20200515231107-62868271d710/go.mod h1:JPm5cTfu1K+qDFRbiHy0sOlHUylYQbpl356sdYFD8V4=
+github.com/tailscale/wireguard-go v0.0.0-20200615180905-687c10194779 h1:zg0rgvhBZGA4nvh17nDKcqkEXw6Nbc/Ma2VBvLaW7LU=
+github.com/tailscale/wireguard-go v0.0.0-20200615180905-687c10194779/go.mod h1:JPm5cTfu1K+qDFRbiHy0sOlHUylYQbpl356sdYFD8V4=
 github.com/tcnksm/go-httpstat v0.2.0 h1:rP7T5e5U2HfmOBmZzGgGZjBQ5/GluWUylujl0tJ04I0=
 github.com/tcnksm/go-httpstat v0.2.0/go.mod h1:s3JVJFtQxtBEBC9dwcdTTXS9xFnM3SXAZwPG41aurT8=
 github.com/toqueteos/webbrowser v1.2.0 h1:tVP/gpK69Fx+qMJKsLE7TD8LuGWPnEV71wBN9rrstGQ=

wgengine/userspace.go

@@ -486,7 +486,10 @@ func (e *userspaceEngine) pinger(peerKey wgcfg.Key, ips []wgcfg.IP) {
 	p.run(ctx, peerKey, ips, srcIP)
 }
 
-func configSignatures(cfg *wgcfg.Config, routerCfg *router.Config) (string, string, error) {
+// configSignatures returns string signatures for the given configs.
+// The exact strings should be considered opaque; the only guarantee is that
+// if cfg or routerCfg change, so do their signatures.
+func configSignatures(cfg *wgcfg.Config, routerCfg *router.Config) (configSig, engineSig string, err error) {
 	// TODO(apenwarr): get rid of uapi stuff for in-process comms
 	uapi, err := cfg.ToUAPI()
 	if err != nil {
@@ -537,9 +540,8 @@ func (e *userspaceEngine) Reconfig(cfg *wgcfg.Config, routerCfg *router.Config)
 	e.lastRouterSig = rc
 	e.lastCfg = cfg.Copy()
 
-	e.logf("wgengine: Reconfig: configuring userspace wireguard engine")
-
 	if engineChanged {
+		e.logf("wgengine: Reconfig: configuring userspace wireguard config")
 		// Tell magicsock about the new (or initial) private key
 		// (which is needed by DERP) before wgdev gets it, as wgdev
 		// will start trying to handshake, which we want to be able to
@@ -557,6 +559,7 @@ func (e *userspaceEngine) Reconfig(cfg *wgcfg.Config, routerCfg *router.Config)
 	}
 
 	if routerChanged {
+		e.logf("wgengine: Reconfig: configuring router")
 		if err := e.router.Set(routerCfg); err != nil {
 			return err
 		}