netutil

func ListenConfig ¶

func ListenConfig() (lc *net.ListenConfig)

ListenConfig returns the default net.ListenConfig used by the plain-DNS servers in this module.

TODO(a.garipov): Add tests.

TODO(a.garipov): Add an option to not set SO_REUSEPORT on Unix to prevent issues with OpenWrt.

See https://github.com/AdguardTeam/AdGuardHome/issues/5872.

TODO(a.garipov): DRY with AdGuard DNS when we can.

func SortIPAddrs ¶

func SortIPAddrs(addrs []net.IPAddr, preferIPv6 bool)

SortIPAddrs sorts addrs in accordance with the protocol preferences. Invalid addresses are sorted near the end. Zones are ignored.

TODO(a.garipov): Use netip.Addr instead of net.IPAddr everywhere where this is called.

package main

import (
	"fmt"
	"net"

	"github.com/AdguardTeam/dnsproxy/internal/netutil"
)

func main() {
	printAddrs := func(header string, addrs []net.IPAddr) {
		fmt.Printf("%s:\n", header)
		for i, a := range addrs {
			fmt.Printf("%d: %s\n", i+1, a.IP)
		}

		fmt.Println()
	}

	addrs := []net.IPAddr{{
		IP: net.ParseIP("1.2.3.4"),
	}, {
		IP: net.ParseIP("1.2.3.5"),
	}, {
		IP: net.ParseIP("2a00::1234"),
	}, {
		IP: net.ParseIP("2a00::1235"),
	}, {
		IP: nil,
	}}
	netutil.SortIPAddrs(addrs, false)
	printAddrs("IPv4 preferred", addrs)

	netutil.SortIPAddrs(addrs, true)
	printAddrs("IPv6 preferred", addrs)

}

Output:


IPv4 preferred:
1: 1.2.3.4
2: 1.2.3.5
3: 2a00::1234
4: 2a00::1235
5: <nil>

IPv6 preferred:
1: 2a00::1234
2: 2a00::1235
3: 1.2.3.4
4: 1.2.3.5
5: <nil>

func SortNetIPAddrs ¶

func SortNetIPAddrs(addrs []netip.Addr, preferIPv6 bool)

SortNetIPAddrs sorts addrs in accordance with the protocol preferences. Invalid addresses are sorted near the end. Zones are ignored.

func UDPGetOOBSize ¶

func UDPGetOOBSize() (oobSize int)

UDPGetOOBSize returns maximum size of the received OOB data.

func UDPRead ¶

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

UDPRead reads the message from conn using buf and receives a control-message payload of size udpOOBSize from it. It returns the number of bytes copied into buf 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.