upstream

Documentation

Index

• Variables
• func LookupParallel(ctx context.Context, resolvers []*Resolver, host string) ([]net.IPAddr, error)
• type Options
• type Resolver
  • func NewResolver(resolverAddress string, timeout time.Duration) *Resolver
  • func (r *Resolver) LookupIPAddr(ctx context.Context, host string) ([]net.IPAddr, error)
• type TLSPool
  • func (n *TLSPool) Create() (net.Conn, error)
  • func (n *TLSPool) Get() (net.Conn, error)
  • func (n *TLSPool) Put(c net.Conn)
• type Upstream
  • func AddressToUpstream(address string, opts Options) (Upstream, error)
  • func ExchangeParallel(u []Upstream, req *dns.Msg) (*dns.Msg, Upstream, error)

Variables

var DohMaxConnsPerHost = 0

DohMaxConnsPerHost controls the maximum number of connections per host nolint

var RootCAs *x509.CertPool

RootCAs is the CertPool that must be used by all upstreams Redefining RootCAs makes sense on iOS to overcome the 15MB memory limit of the NEPacketTunnelProvider nolint

Functions

func LookupParallel

func LookupParallel(ctx context.Context, resolvers []*Resolver, host string) ([]net.IPAddr, error)

LookupParallel starts parallel lookup for host ip with many Resolvers First answer without error will be returned Return nil and error if count of errors equals count of resolvers

Types

type Options

type Options struct {
	// Bootstrap is a list of plain DNS servers to be used to resolve DOH/DOT hostnames (if any)
	Bootstrap []string

	// Timeout is the default upstream timeout. Also, it is used as a timeout for bootstrap DNS requests.
	// timeout=0 means infinite timeout.
	Timeout time.Duration

	// ServerIP allows specifying the resolver's IP address. In the case if it's specified,
	// bootstrap DNS servers won't be used at all.
	ServerIP net.IP
}

Options for AddressToUpstream func

type Resolver

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

Resolver is wrapper for resolver and it's address

func NewResolver

func NewResolver(resolverAddress string, timeout time.Duration) *Resolver

NewResolver creates an instance of Resolver structure with defined net.Resolver and it's address resolverAddress is address of net.Resolver The host in the address parameter of Dial func will always be a literal IP address (from documentation)

func (*Resolver) LookupIPAddr

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

LookupIPAddr returns result of LookupIPAddr method of Resolver's net.Resolver

type TLSPool

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

TLSPool is a connections pool for the DNS-over-TLS Upstream.

Example:

pool := TLSPool{Address: "tls://1.1.1.1:853"}
netConn, err := pool.Get()
if err != nil {panic(err)}
c := dns.Conn{Conn: netConn}
q := dns.Msg{}
q.SetQuestion("google.com.", dns.TypeA)
log.Println(q)
err = c.WriteMsg(&q)
if err != nil {panic(err)}
r, err := c.ReadMsg()
if err != nil {panic(err)}
log.Println(r)
pool.Put(c.Conn)

func (*TLSPool) Create

func (n *TLSPool) Create() (net.Conn, error)

Create creates a new connection for the pool (but not puts it there)

func (*TLSPool) Get

func (n *TLSPool) Get() (net.Conn, error)

Get gets or creates a new TLS connection

func (*TLSPool) Put

func (n *TLSPool) Put(c net.Conn)

Put returns connection to the pool

type Upstream

type Upstream interface {
	Exchange(m *dns.Msg) (*dns.Msg, error)
	Address() string
}

Upstream is an interface for a DNS resolver

func AddressToUpstream

func AddressToUpstream(address string, opts Options) (Upstream, error)

AddressToUpstream converts the specified address to an Upstream instance * 8.8.8.8:53 -- plain DNS * tcp://8.8.8.8:53 -- plain DNS over TCP * tls://1.1.1.1 -- DNS-over-TLS * https://dns.adguard.com/dns-query -- DNS-over-HTTPS * sdns://... -- DNS stamp (see https://dnscrypt.info/stamps-specifications)

func ExchangeParallel

func ExchangeParallel(u []Upstream, req *dns.Msg) (*dns.Msg, Upstream, error)

ExchangeParallel function is called to parallel exchange dns request by many upstreams First answer without error will be returned We will return nil and error if count of errors equals count of upstreams