madns

README

go-multiaddr-dns

Resolve /dns4, /dns6, and /dnsaddr multiaddrs.

> madns /dnsaddr/ipfs.io/ipfs/QmSoLju6m7xTh3DuokvT3886QRYqxAzb1kShaanJgW36yx
/ip4/104.236.151.122/tcp/4001/ipfs/QmSoLju6m7xTh3DuokvT3886QRYqxAzb1kShaanJgW36yx
/ip6/2604:a880:1:20::1d9:6001/tcp/4001/ipfs/QmSoLju6m7xTh3DuokvT3886QRYqxAzb1kShaanJgW36yx
/ip6/fc3d:9a4e:3c96:2fd2:1afa:18fe:8dd2:b602/tcp/4001/ipfs/QmSoLju6m7xTh3DuokvT3886QRYqxAzb1kShaanJgW36yx
/dns4/jupiter.i.ipfs.io/tcp/4001/ipfs/QmSoLju6m7xTh3DuokvT3886QRYqxAzb1kShaanJgW36yx
/dns6/jupiter.i.ipfs.io/tcp/4001/ipfs/QmSoLju6m7xTh3DuokvT3886QRYqxAzb1kShaanJgW36yx

In more detail:

> madns /dns6/example.net
/ip6/2001:db8::a3
/ip6/2001:db8::a4
...

> madns /dns4/example.net/tcp/443/wss
/ip4/192.0.2.1/tcp/443/wss
/ip4/192.0.2.2/tcp/443/wss

# No-op if it's not a dns-ish address.

> madns /ip4/127.0.0.1/tcp/8080
/ip4/127.0.0.1/tcp/8080

# /dnsaddr resolves by looking up TXT records.

> dig +short TXT _dnsaddr.example.net
"dnsaddr=/ip6/2001:db8::a3/tcp/443/wss/ipfs/Qmfoo"
"dnsaddr=/ip6/2001:db8::a4/tcp/443/wss/ipfs/Qmbar"
"dnsaddr=/ip4/192.0.2.1/tcp/443/wss/ipfs/Qmfoo"
"dnsaddr=/ip4/192.0.2.2/tcp/443/wss/ipfs/Qmbar"
...

# /dnsaddr returns addrs which encapsulate whatever /dnsaddr encapsulates too.

> madns example.net/ipfs/Qmfoo
info: changing query to /dnsaddr/example.net/ipfs/Qmfoo
/ip6/2001:db8::a3/tcp/443/wss/ipfs/Qmfoo
/ip4/192.0.2.1/tcp/443/wss/ipfs/Qmfoo

# TODO -p filters by protocol stacks.

> madns -p /ip6/tcp/wss /dnsaddr/example.net
/ip6/2001:db8::a3/tcp/443/wss/ipfs/Qmfoo
/ip6/2001:db8::a4/tcp/443/wss/ipfs/Qmbar

# TODO -c filters by CIDR
> madns -c /ip4/104.236.76.0/ipcidr/24 /dnsaddr/example.net
/ip4/192.0.2.2/tcp/443/wss/ipfs/Qmbar

Documentation

Index

• Constants
• Variables
• func Matches(maddr ma.Multiaddr) (matches bool)
• func Resolve(ctx context.Context, maddr ma.Multiaddr) ([]ma.Multiaddr, error)
• type BasicResolver
• type MockResolver
  • func (r *MockResolver) LookupIPAddr(ctx context.Context, name string) ([]net.IPAddr, error)
  • func (r *MockResolver) LookupTXT(ctx context.Context, name string) ([]string, error)
• type Option
  • func WithDefaultResolver(def BasicResolver) Option
  • func WithDomainResolver(domain string, rslv BasicResolver) Option
• type Resolver
  • func NewResolver(opts ...Option) (*Resolver, error)
  • func (r *Resolver) LookupIPAddr(ctx context.Context, domain string) ([]net.IPAddr, error)
  • func (r *Resolver) LookupTXT(ctx context.Context, txt string) ([]string, error)
  • func (r *Resolver) Resolve(ctx context.Context, maddr ma.Multiaddr) ([]ma.Multiaddr, error)

Constants

const (
	// Deprecated: use ma.P_DNS
	P_DNS = ma.P_DNS
	// Deprecated: use ma.P_DNS4
	P_DNS4 = ma.P_DNS4
	// Deprecated: use ma.P_DNS6
	P_DNS6 = ma.P_DNS6
	// Deprecated: use ma.P_DNSADDR
	P_DNSADDR = ma.P_DNSADDR
)

Extracted from source of truth for multicodec codes: https://github.com/multiformats/multicodec

Variables

var DefaultResolver = &Resolver{def: net.DefaultResolver}

var Dns4Protocol = ma.ProtocolWithCode(P_DNS4)

Deprecated: use ma.ProtocolWithCode(P_DNS4)

var Dns6Protocol = ma.ProtocolWithCode(P_DNS6)

Deprecated: use ma.ProtocolWithCode(P_DNS6)

var DnsProtocol = ma.ProtocolWithCode(P_DNS)

Deprecated: use ma.ProtocolWithCode(P_DNS)

var DnsaddrProtocol = ma.ProtocolWithCode(P_DNSADDR)

Deprecated: use ma.ProtocolWithCode(P_DNSADDR)

var ResolvableProtocols = []ma.Protocol{DnsaddrProtocol, Dns4Protocol, Dns6Protocol, DnsProtocol}

Functions

func Matches

func Matches(maddr ma.Multiaddr) (matches bool)

func Resolve

func Resolve(ctx context.Context, maddr ma.Multiaddr) ([]ma.Multiaddr, error)

Types

type BasicResolver

type BasicResolver interface {
	LookupIPAddr(context.Context, string) ([]net.IPAddr, error)
	LookupTXT(context.Context, string) ([]string, error)
}

BasicResolver is a low level interface for DNS resolution

type MockResolver

type MockResolver struct {
	IP  map[string][]net.IPAddr
	TXT map[string][]string
}

func (*MockResolver) LookupIPAddr

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

func (*MockResolver) LookupTXT

func (r *MockResolver) LookupTXT(ctx context.Context, name string) ([]string, error)

type Option

type Option func(*Resolver) error

func WithDefaultResolver

func WithDefaultResolver(def BasicResolver) Option

WithDefaultResolver is an option that specifies the default basic resolver, which resolves any TLD that doesn't have a custom resolver. Defaults to net.DefaultResolver

func WithDomainResolver

func WithDomainResolver(domain string, rslv BasicResolver) Option

WithDomainResolver specifies a custom resolver for a domain/TLD. Custom resolver selection matches domains left to right, with more specific resolvers superseding generic ones.

type Resolver

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

Resolver is an object capable of resolving dns multiaddrs by using one or more BasicResolvers; it supports custom per domain/TLD resolvers. It also implements the BasicResolver interface so that it can act as a custom per domain/TLD resolver.

func NewResolver

func NewResolver(opts ...Option) (*Resolver, error)

NewResolver creates a new Resolver instance with the specified options

func (*Resolver) LookupIPAddr

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

func (*Resolver) LookupTXT

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

func (*Resolver) Resolve

func (r *Resolver) Resolve(ctx context.Context, maddr ma.Multiaddr) ([]ma.Multiaddr, error)

Resolve resolves a DNS multiaddr.