doh

Documentation

Overview

Package doh (aka) internal/resolver/doh is a resolver implementation which handles (DoH) lookups via remote servers.

Typical usage is pretty straightforward. Create the resolver once then use it to resolve dns.Msgs.

res, err := dohresolver.New(dohresolver.Config{....}, &http.Client)
for {
    qname, msg := getMsg()
    if res.InBailiwick(qname) {
       reply, details, err := res.Resolve(*dns.Msg)
       if err == nil {
          handleReply(reply)
           ..
       }
    }
}

Index

• func New(config Config, httpClient HTTPClientDo) (*remote, error)
• type Config
• type HTTPClientDo

Functions

func New

func New(config Config, httpClient HTTPClientDo) (*remote, error)

New creates a remote struct which supplies the internal/resolver/Resolver interface. A constructor Config is pass in which contains the various parameters needed to create the Resolver. We have to re-check a lot of what the cli programs using us have already done, but that's unavoidable really as we can't rely on callers to get our config right.

Types

type Config

type Config struct {
	UseGetMethod    bool // Instead of the default POST
	GeneratePadding bool // RFC8467 query and response padding with zeroes

	ECSRedactResponse       bool       // If server-side synthesis/set remove ECS before returning to client
	ECSRemove               bool       // If ECS options are removed from inbound queries
	ECSRequestIPv4PrefixLen int        // Server-side synthesis if client address is IPv4 - 0=no synth
	ECSRequestIPv6PrefixLen int        // Server-side synthesis if client address is IPv6 - 0=no synth
	ECSSetCIDR              *net.IPNet // Set the ECS locally with this CIDR - cannot have ECSRequest* as well

	bestserver.LatencyConfig          // Latency Config and Server URLs are passed down
	ServerURLs               []string // to the DoH resolver.
}

Config is passed to the New() constructor.

type HTTPClientDo

type HTTPClientDo interface {
	Do(*http.Request) (*http.Response, error)
}

HTTPClientDo is an interface which implements http.Client.Do() - the only http.Client method used by the DoH resolver. It mainly exists so we can supply a mock http.Client for testing. We cannot provide an alternate http.Client because http.Client is an implementation struct rather than an interface.