Update dependencies

vendor/tailscale.com/wgengine/router/consolidating_router.go

@@ -0,0 +1,59 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package router
+
+import (
+	"go4.org/netipx"
+	"tailscale.com/types/logger"
+)
+
+// ConsolidatingRoutes wraps a Router with logic that consolidates Routes
+// whenever Set is called. It attempts to consolidate cfg.Routes into the
+// smallest possible set.
+func ConsolidatingRoutes(logf logger.Logf, router Router) Router {
+	return &consolidatingRouter{Router: router, logf: logger.WithPrefix(logf, "router: ")}
+}
+
+type consolidatingRouter struct {
+	Router
+	logf logger.Logf
+}
+
+// Set implements Router and attempts to consolidate cfg.Routes into the
+// smallest possible set.
+func (cr *consolidatingRouter) Set(cfg *Config) error {
+	return cr.Router.Set(cr.consolidateRoutes(cfg))
+}
+
+func (cr *consolidatingRouter) consolidateRoutes(cfg *Config) *Config {
+	if cfg == nil {
+		return nil
+	}
+	if len(cfg.Routes) < 2 {
+		return cfg
+	}
+	if len(cfg.Routes) == 2 && cfg.Routes[0].Addr().Is4() != cfg.Routes[1].Addr().Is4() {
+		return cfg
+	}
+	var builder netipx.IPSetBuilder
+	for _, route := range cfg.Routes {
+		builder.AddPrefix(route)
+	}
+	set, err := builder.IPSet()
+	if err != nil {
+		cr.logf("consolidateRoutes failed, keeping existing routes: %s", err)
+		return cfg
+	}
+	newRoutes := set.Prefixes()
+	oldLength := len(cfg.Routes)
+	newLength := len(newRoutes)
+	if oldLength == newLength {
+		// Nothing consolidated, return as-is.
+		return cfg
+	}
+	cr.logf("consolidated %d routes down to %d", oldLength, newLength)
+	newCfg := *cfg
+	newCfg.Routes = newRoutes
+	return &newCfg
+}