132 lines
3.0 KiB
Go
132 lines
3.0 KiB
Go
package aghnet
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import (
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"fmt"
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"net"
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"time"
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"github.com/AdguardTeam/golibs/log"
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)
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// IPVersion is a alias for int for documentation purposes. Use it when the
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// integer means IP version.
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type IPVersion = int
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// IP version constants.
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const (
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IPVersion4 IPVersion = 4
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IPVersion6 IPVersion = 6
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)
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// NetIface is the interface for network interface methods.
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type NetIface interface {
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Addrs() ([]net.Addr, error)
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}
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// IfaceIPAddrs returns the interface's IP addresses.
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func IfaceIPAddrs(iface NetIface, ipv IPVersion) (ips []net.IP, err error) {
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switch ipv {
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case IPVersion4, IPVersion6:
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// Go on.
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default:
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return nil, fmt.Errorf("invalid ip version %d", ipv)
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}
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addrs, err := iface.Addrs()
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if err != nil {
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return nil, err
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}
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for _, a := range addrs {
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var ip net.IP
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switch a := a.(type) {
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case *net.IPAddr:
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ip = a.IP
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case *net.IPNet:
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ip = a.IP
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default:
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continue
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}
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// Assume that net.(*Interface).Addrs can only return valid IPv4 and
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// IPv6 addresses. Thus, if it isn't an IPv4 address, it must be an
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// IPv6 one.
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ip4 := ip.To4()
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if ipv == IPVersion4 {
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if ip4 != nil {
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ips = append(ips, ip4)
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}
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} else if ip4 == nil {
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ips = append(ips, ip)
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}
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}
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return ips, nil
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}
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// IfaceDNSIPAddrs returns IP addresses of the interface suitable to send to
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// clients as DNS addresses. If err is nil, addrs contains either no addresses
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// or at least two.
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//
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// It makes up to maxAttempts attempts to get the addresses if there are none,
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// each time using the provided backoff. Sometimes an interface needs a few
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// seconds to really initialize.
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//
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// See https://github.com/AdguardTeam/AdGuardHome/issues/2304.
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func IfaceDNSIPAddrs(
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iface NetIface,
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ipv IPVersion,
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maxAttempts int,
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backoff time.Duration,
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) (addrs []net.IP, err error) {
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var n int
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for n = 1; n <= maxAttempts; n++ {
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addrs, err = IfaceIPAddrs(iface, ipv)
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if err != nil {
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return nil, fmt.Errorf("getting ip addrs: %w", err)
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}
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if len(addrs) > 0 {
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break
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}
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log.Debug("dhcpv%d: attempt %d: no ip addresses", ipv, n)
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time.Sleep(backoff)
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}
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n--
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switch len(addrs) {
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case 0:
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// Don't return errors in case the users want to try and enable the DHCP
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// server later.
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t := time.Duration(n) * backoff
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log.Error("dhcpv%d: no ip for iface after %d attempts and %s", ipv, n, t)
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return nil, nil
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case 1:
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// Some Android devices use 8.8.8.8 if there is not a secondary DNS
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// server. Fix that by setting the secondary DNS address to the same
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// address.
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//
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// See https://github.com/AdguardTeam/AdGuardHome/issues/1708.
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log.Debug("dhcpv%d: setting secondary dns ip to itself", ipv)
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addrs = append(addrs, addrs[0])
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default:
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// Go on.
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}
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log.Debug("dhcpv%d: got addresses %s after %d attempts", ipv, addrs, n)
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return addrs, nil
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}
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// interfaceName is a string containing network interface's name. The name is
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// used in file walking methods.
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type interfaceName string
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// Use interfaceName in the OS-independent code since it's actually only used in
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// several OS-dependent implementations which causes linting issues.
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var _ = interfaceName("")
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