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