a6e18c4700
Merge in DNS/adguard-home from 2304-dncp-backoff to master Updates #2304. Squashed commit of the following: commit c9bff8b27c6b031d43a7dd98152adcde7f49fff1 Author: Ainar Garipov <A.Garipov@AdGuard.COM> Date: Fri Nov 27 14:08:03 2020 +0300 dhcpd: try for 5s instead of 10s commit 983cf471832de0e7762b8b6e0a4ba9bb76ecadfc Author: Ainar Garipov <A.Garipov@AdGuard.COM> Date: Wed Nov 25 19:58:41 2020 +0300 dhcpd: wait for interfaces' ip addresses to appear
124 lines
2.9 KiB
Go
124 lines
2.9 KiB
Go
package dhcpd
|
|
|
|
import (
|
|
"fmt"
|
|
"net"
|
|
"time"
|
|
|
|
"github.com/AdguardTeam/golibs/log"
|
|
)
|
|
|
|
// ipVersion is a documentational alias for int. Use it when the integer means
|
|
// IP version.
|
|
type ipVersion = int
|
|
|
|
// IP version constants.
|
|
const (
|
|
ipVersion4 ipVersion = 4
|
|
ipVersion6 ipVersion = 6
|
|
)
|
|
|
|
// netIface is the interface for network interface methods.
|
|
type netIface interface {
|
|
Addrs() ([]net.Addr, error)
|
|
}
|
|
|
|
// ifaceIPAddrs returns the interface's IP addresses.
|
|
func ifaceIPAddrs(iface netIface, ipv ipVersion) (ips []net.IP, err error) {
|
|
addrs, err := iface.Addrs()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
for _, a := range addrs {
|
|
var ip net.IP
|
|
switch a := a.(type) {
|
|
case *net.IPAddr:
|
|
ip = a.IP
|
|
case *net.IPNet:
|
|
ip = a.IP
|
|
default:
|
|
continue
|
|
}
|
|
|
|
// Assume that net.(*Interface).Addrs can only return valid IPv4
|
|
// and IPv6 addresses. Thus, if it isn't an IPv4 address, it
|
|
// must be an IPv6 one.
|
|
switch ipv {
|
|
case ipVersion4:
|
|
if ip4 := ip.To4(); ip4 != nil {
|
|
ips = append(ips, ip4)
|
|
}
|
|
case ipVersion6:
|
|
if ip6 := ip.To4(); ip6 == nil {
|
|
ips = append(ips, ip)
|
|
}
|
|
default:
|
|
return nil, fmt.Errorf("invalid ip version %d", ipv)
|
|
}
|
|
}
|
|
|
|
return ips, nil
|
|
}
|
|
|
|
// Currently used defaults for ifaceDNSAddrs.
|
|
const (
|
|
defaultMaxAttempts int = 10
|
|
|
|
defaultBackoff time.Duration = 500 * time.Millisecond
|
|
)
|
|
|
|
// ifaceDNSIPAddrs returns IP addresses of the interface suitable to send to
|
|
// clients as DNS addresses. If err is nil, addrs contains either no addresses
|
|
// or at least two.
|
|
//
|
|
// It makes up to maxAttempts attempts to get the addresses if there are none,
|
|
// each time using the provided backoff. Sometimes an interface needs a few
|
|
// seconds to really ititialize.
|
|
//
|
|
// See https://github.com/AdguardTeam/AdGuardHome/issues/2304.
|
|
func ifaceDNSIPAddrs(
|
|
iface netIface,
|
|
ipv ipVersion,
|
|
maxAttempts int,
|
|
backoff time.Duration,
|
|
) (addrs []net.IP, err error) {
|
|
var n int
|
|
waitForIP:
|
|
for n = 1; n <= maxAttempts; n++ {
|
|
addrs, err = ifaceIPAddrs(iface, ipv)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("getting ip addrs: %w", err)
|
|
}
|
|
|
|
switch len(addrs) {
|
|
case 0:
|
|
log.Debug("dhcpv%d: attempt %d: no ip addresses", ipv, n)
|
|
|
|
time.Sleep(backoff)
|
|
case 1:
|
|
// Some Android devices use 8.8.8.8 if there is not
|
|
// a secondary DNS server. Fix that by setting the
|
|
// secondary DNS address to the same address.
|
|
//
|
|
// See https://github.com/AdguardTeam/AdGuardHome/issues/1708.
|
|
log.Debug("dhcpv%d: setting secondary dns ip to itself", ipv)
|
|
addrs = append(addrs, addrs[0])
|
|
|
|
fallthrough
|
|
default:
|
|
break waitForIP
|
|
}
|
|
}
|
|
|
|
if len(addrs) == 0 {
|
|
// Don't return errors in case the users want to try and enable
|
|
// the DHCP server later.
|
|
log.Error("dhcpv%d: no ip address for interface after %d attempts and %s", ipv, n, time.Duration(n)*backoff)
|
|
} else {
|
|
log.Debug("dhcpv%d: got addresses %s after %d attempts", ipv, addrs, n)
|
|
}
|
|
|
|
return addrs, nil
|
|
}
|