agdnet

Documentation

Overview

Package agdnet contains network-related utilities.

TODO(a.garipov): Move stuff to netutil.

Index

• func AndroidMetricDomainReplacement(fqdn string) (repl string)
• func NormalizeDomain(fqdn string) (host string)
• func NormalizeQueryDomain(host string) (norm string)
• type CachingResolver
  • func NewCachingResolver(resolver Resolver, ttl time.Duration) (c *CachingResolver)
  • func (c *CachingResolver) LookupNetIP(ctx context.Context, fam netutil.AddrFamily, host string) (ips []netip.Addr, err error)
• type DefaultResolver
  • func (DefaultResolver) LookupNetIP(ctx context.Context, fam netutil.AddrFamily, host string) (ips []netip.Addr, err error)
• type PrefixNetAddr
  • func (addr *PrefixNetAddr) Network() (n string)
  • func (addr *PrefixNetAddr) String() (n string)
• type Resolver

Examples

• AndroidMetricDomainReplacement
• PrefixNetAddr (String)

Functions

func AndroidMetricDomainReplacement

func AndroidMetricDomainReplacement(fqdn string) (repl string)

AndroidMetricDomainReplacement returns an empty string if fqdn is not ending with androidMetricFQDNSuffix. Otherwise it returns an appropriate replacement domain name.

Example

package main

import (
	"fmt"

	"github.com/AdguardTeam/AdGuardDNS/internal/agdnet"
)

func main() {
	printResult := func(input string) {
		fmt.Printf("%-42q: %q\n", input, agdnet.AndroidMetricDomainReplacement(input))
	}

	anAndroidDomain := "12345678-dnsotls-ds.metric.gstatic.com."
	printResult(anAndroidDomain)

	anAndroidDomain = "123456-dnsohttps-ds.metric.gstatic.com."
	printResult(anAndroidDomain)

	notAndroidDomain := "example.com"
	printResult(notAndroidDomain)

}

Output:

"12345678-dnsotls-ds.metric.gstatic.com." : "00000000-dnsotls-ds.metric.gstatic.com."
"123456-dnsohttps-ds.metric.gstatic.com." : "000000-dnsohttps-ds.metric.gstatic.com."
"example.com"                             : ""

func NormalizeDomain

func NormalizeDomain(fqdn string) (host string)

NormalizeDomain returns lowercased version of the host without the final dot.

TODO(a.garipov): Move to golibs.

func NormalizeQueryDomain

func NormalizeQueryDomain(host string) (norm string)

NormalizeQueryDomain returns a lowercased version of the host without the final dot, unless the host is ".", in which case it returns the unchanged host. That is the special case to allow matching queries like:

dig IN NS '.'

Types

type CachingResolver

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

CachingResolver caches resolved results for hosts for a certain time, regardless of the actual TTLs of the records. It is used for caching the results of lookups of hostnames that don't change their IP addresses often.

func NewCachingResolver

func NewCachingResolver(resolver Resolver, ttl time.Duration) (c *CachingResolver)

NewCachingResolver returns a new caching resolver.

func (*CachingResolver) LookupNetIP

func (c *CachingResolver) LookupNetIP(
	ctx context.Context,
	fam netutil.AddrFamily,
	host string,
) (ips []netip.Addr, err error)

LookupNetIP implements the Resolver interface for *CachingResolver. host should be normalized. Slice ips and its elements must not be mutated.

type DefaultResolver

type DefaultResolver struct{}

DefaultResolver uses net.DefaultResolver to resolve addresses.

func (DefaultResolver) LookupNetIP

func (DefaultResolver) LookupNetIP(
	ctx context.Context,
	fam netutil.AddrFamily,
	host string,
) (ips []netip.Addr, err error)

LookupNetIP implements the Resolver interface for DefaultResolver.

type PrefixNetAddr

type PrefixNetAddr struct {
	Prefix netip.Prefix
	Net    string
	Port   uint16
}

PrefixNetAddr is a wrapper around netip.Prefix that makes it a net.Addr.

Example (String)

package main

import (
	"fmt"
	"net/netip"

	"github.com/AdguardTeam/AdGuardDNS/internal/agdnet"
)

func main() {
	fmt.Println(&agdnet.PrefixNetAddr{
		Prefix: netip.MustParsePrefix("1.2.3.4/32"),
		Net:    "",
		Port:   5678,
	})
	fmt.Println(&agdnet.PrefixNetAddr{
		Prefix: netip.MustParsePrefix("1.2.3.0/24"),
		Net:    "",
		Port:   5678,
	})

}

Output:

1.2.3.4:5678
1.2.3.0:5678/24

func (*PrefixNetAddr) Network

func (addr *PrefixNetAddr) Network() (n string)

Network implements the net.Addr interface for *PrefixNetAddr.

func (*PrefixNetAddr) String

func (addr *PrefixNetAddr) String() (n string)

String implements the net.Addr interface for *PrefixNetAddr. It returns either a simple IP:port address or one with the prefix length appended after a slash, depending on whether or not subnet is a single-address subnet. This is done to make using the IP:port part easier to split off using functions like strings.Cut.

type Resolver

type Resolver interface {
	// LookupNetIP returns a slice of host's IP addresses of family specified by
	// fam, which must be either [netutil.AddrFamilyIPv4] or
	// [netutil.AddrFamilyIPv6].
	LookupNetIP(
		ctx context.Context,
		fam netutil.AddrFamily,
		host string,
	) (ips []netip.Addr, err error)
}

Resolver is the DNS resolver interface.

See net.Resolver.

TODO(a.garipov): Move to golibs and unite with the one in module dnsproxy.