dnsgrab

Documentation

Index

• Variables
• type Cache
  • func NewInMemoryCache(size int) Cache
• type Server
  • func Listen(cacheSize int, listenAddr string, defaultDNSServer func() string) (Server, error)
  • func ListenWithCache(listenAddr string, defaultDNSServer func() string, cache Cache) (Server, error)

Variables

var (
	ErrUnsupportedQueryType = errors.New("unsupported query type")
)

Types

type Cache

type Cache interface {
	NameByIP(ip []byte) (name string, found bool)

	IPByName(name string) (ip []byte, found bool)

	Add(name string, ip []byte)

	MarkFresh(name string, ip []byte)

	NextSequence() uint32
}

Cache defines the API for a cache of names to IPs and vice versa

func NewInMemoryCache

func NewInMemoryCache(size int) Cache

type Server

type Server interface {
	// LocalAddr() returns the address at which this server is listening
	LocalAddr() net.Addr

	// Serve() runs the server (blocks until server ends)
	Serve() error

	// Close closes the server's network listener.
	Close() error

	// ProcessQuery processes a DNS query and returns the response bytes, the number of answers in the response, and any error encountered while
	// processing the query.
	ProcessQuery(b []byte) ([]byte, int, error)

	// ReverseLookup resolves the given fake IP address into the original hostname. If the given IP is not a fake IP,
	// this simply returns the provided IP in string form. If the IP is not found, this returns false.
	ReverseLookup(ip net.IP) (string, bool)
}

Server is a dns server that resolves queries for A records into fake IP addresses within the Class-E address space and allows reverse resolution of those back into the originally queried hostname.

func Listen

func Listen(cacheSize int, listenAddr string, defaultDNSServer func() string) (Server, error)

Listen creates a new server listening at the given listenAddr and that forwards queries it can't handle to the given defaultDNSServer. It uses an in-memory cache constrained by cacheSize.

func ListenWithCache

func ListenWithCache(listenAddr string, defaultDNSServer func() string, cache Cache) (Server, error)

ListenWithCache is like Listen but taking any Cache implementation.