proxyutil

Documentation

Overview

Package proxyutil contains helper functions that are used in all other dnsproxy packages

Index

• Variables
• func AppendIPAddrs(ipAddrs *[]net.IPAddr, answers []dns.RR)
• func ContainsIP(ips []net.IP, ip net.IP) bool
• func DNSSize(isUDP bool, r *dns.Msg) int
• func GetIPFromDNSRecord(r dns.RR) net.IP
• func IsConnClosed(err error) bool
• func ReadPrefixed(conn net.Conn) ([]byte, error)
• func SortIPAddrs(ipAddrs []net.IPAddr) []net.IPAddr
• func UDPGetOOBSize() (oobSize int)
• func UDPRead(c *net.UDPConn, buf []byte, udpOOBSize int) (n int, localIP net.IP, remoteAddr *net.UDPAddr, err error)
• func UDPSetOptions(c *net.UDPConn) (err error)
• func UDPWrite(data []byte, conn *net.UDPConn, remoteAddr *net.UDPAddr, localIP net.IP) (n int, err error)
• func WritePrefixed(b []byte, conn net.Conn) error

Variables

var ErrTooLarge = errors.New("DNS message is too large")

ErrTooLarge - DNS message is larger than 64kb

Functions

func AppendIPAddrs

func AppendIPAddrs(ipAddrs *[]net.IPAddr, answers []dns.RR)

AppendIPAddrs appends the IP addresses got from dns.RR to the specified array

func ContainsIP

func ContainsIP(ips []net.IP, ip net.IP) bool

ContainsIP checks if the specified IP is in the array

func DNSSize

func DNSSize(isUDP bool, r *dns.Msg) int

DNSSize returns if buffer size *advertised* in the requests OPT record. Or when the request was over TCP, we return the maximum allowed size of 64K.

func GetIPFromDNSRecord

func GetIPFromDNSRecord(r dns.RR) net.IP

GetIPFromDNSRecord - extracts IP address for a DNS record returns null if the record is of a wrong type

func IsConnClosed

func IsConnClosed(err error) bool

IsConnClosed - checks if the error signals of a closed server connecting

func ReadPrefixed

func ReadPrefixed(conn net.Conn) ([]byte, error)

ReadPrefixed -- reads a DNS message with a 2-byte prefix containing message length

func SortIPAddrs

func SortIPAddrs(ipAddrs []net.IPAddr) []net.IPAddr

SortIPAddrs sorts the specified IP addresses array IPv4 addresses go first, then IPv6 addresses

func UDPGetOOBSize

func UDPGetOOBSize() (oobSize int)

UDPGetOOBSize returns maximum size of the received OOB data.

func UDPRead

func UDPRead(
	c *net.UDPConn,
	buf []byte,
	udpOOBSize int,
) (n int, localIP net.IP, remoteAddr *net.UDPAddr, err error)

UDPRead udpRead reads the message from c using buf receives payload of size udpOOBSize from the UDP socket. It returns the number of bytes copied into buf, the number of bytes copied with OOB and the source address of the message.

func UDPSetOptions

func UDPSetOptions(c *net.UDPConn) (err error)

UDPSetOptions sets flag options on a UDP socket to be able to receive the necessary OOB data.

func UDPWrite

func UDPWrite(
	data []byte,
	conn *net.UDPConn,
	remoteAddr *net.UDPAddr,
	localIP net.IP,
) (n int, err error)

UDPWrite writes the data to the remoteAddr using conn.

func WritePrefixed

func WritePrefixed(b []byte, conn net.Conn) error

WritePrefixed -- write a DNS message to a TCP connection it first writes a 2-byte prefix followed by the message itself