dnsfallback

Documentation

Overview

Package dnsfallback contains a DNS fallback mechanism for starting up Tailscale when the system DNS is broken or otherwise unavailable.

Index

• func Lookup(ctx context.Context, host string) ([]netip.Addr, error)
• func SetCachePath(path string)
• func SetLogger(log logger.Logf) (old logger.Logf)
• func UpdateCache(c *tailcfg.DERPMap)

Functions

func Lookup

func Lookup(ctx context.Context, host string) ([]netip.Addr, error)

func SetCachePath

func SetCachePath(path string)

SetCachePath sets the path to the on-disk DERP map cache that we store and update. Additionally, if a file at this path exists, we load it and merge it with the DERP map baked into the binary.

This function should be called before any calls to UpdateCache, as it is not concurrency-safe.

func SetLogger

func SetLogger(log logger.Logf) (old logger.Logf)

SetLogger sets the logging function that this package will use, and returns the old value (which may be nil).

If this function is never called, or if this function is called with a nil value, 'log.Printf' will be used to print logs.

func UpdateCache

func UpdateCache(c *tailcfg.DERPMap)

UpdateCache stores the DERP map cache back to disk.

The caller must not mutate 'c' after calling this function.