dns

Documentation

Index

• Constants
• func NewResolver(collector module.ResolverMetrics, opts ...optFunc) (*madns.Resolver, error)
• func WithBasicResolver(basic madns.BasicResolver) optFunc
• func WithTTL(ttl time.Duration) optFunc
• type Resolver
  • func (r *Resolver) LookupIPAddr(ctx context.Context, domain string) ([]net.IPAddr, error)
  • func (r *Resolver) LookupTXT(ctx context.Context, txt string) ([]string, error)

Constants

const (
	// DefaultTimeToLive is the default duration a dns result is cached.
	DefaultTimeToLive = 60 * time.Minute
)

DefaultTimeToLive is the default duration a dns result is cached.

Functions

func NewResolver

func NewResolver(collector module.ResolverMetrics, opts ...optFunc) (*madns.Resolver, error)

NewResolver is the factory function for creating an instance of this resolver.

func WithBasicResolver

func WithBasicResolver(basic madns.BasicResolver) optFunc

WithBasicResolver is an option function for setting the basic resolver of this Resolver.

func WithTTL

func WithTTL(ttl time.Duration) optFunc

WithTTL is an option function for setting the time to live for cache entries.

Types

type Resolver

type Resolver struct {
	// contains filtered or unexported fields
}

Resolver is a cache-based dns resolver for libp2p. - DNS cache implementation notes:

• Generic / possibly expected functionality NOT implemented:
• Caches domains for TTL seconds as given by upstream DNS resolver, e.g. [1].
• Possibly pre-expire cached domains so no connection time resolve delay.
• Actual / pragmatic functionality implemented below:
• Caches domains for global (not individual domain record TTL) TTL seconds.
• Cached IP is returned even if cached entry expired; so no connection time resolve delay.
• Detecting expired cached domain triggers async DNS lookup to refresh cached entry.

[1] https://en.wikipedia.org/wiki/Name_server#Caching_name_server

func (*Resolver) LookupIPAddr

func (r *Resolver) LookupIPAddr(ctx context.Context, domain string) ([]net.IPAddr, error)

LookupIPAddr implements BasicResolver interface for libp2p for looking up ip addresses through resolver.

func (*Resolver) LookupTXT

func (r *Resolver) LookupTXT(ctx context.Context, txt string) ([]string, error)

LookupTXT implements BasicResolver interface for libp2p.