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package dns64
import (
"net"
"github.com/coredns/caddy"
"github.com/coredns/coredns/core/dnsserver"
"github.com/coredns/coredns/plugin"
clog "github.com/coredns/coredns/plugin/pkg/log"
"github.com/coredns/coredns/plugin/pkg/upstream"
)
const pluginName = "dns64"
var log = clog.NewWithPlugin(pluginName)
func init() { plugin.Register(pluginName, setup) }
func setup(c *caddy.Controller) error {
dns64, err := dns64Parse(c)
if err != nil {
return plugin.Error(pluginName, err)
}
dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
dns64.Next = next
return dns64
})
return nil
}
func dns64Parse(c *caddy.Controller) (*DNS64, error) {
_, defaultPref, _ := net.ParseCIDR("64:ff9b::/96")
dns64 := &DNS64{
Upstream: upstream.New(),
Prefix: defaultPref,
}
for c.Next() {
args := c.RemainingArgs()
if len(args) == 1 {
pref, err := parsePrefix(c, args[0])
if err != nil {
return nil, err
}
dns64.Prefix = pref
continue
}
if len(args) > 0 {
return nil, c.ArgErr()
}
for c.NextBlock() {
switch c.Val() {
case "prefix":
if !c.NextArg() {
return nil, c.ArgErr()
}
pref, err := parsePrefix(c, c.Val())
if err != nil {
return nil, err
}
dns64.Prefix = pref
case "translate_all":
dns64.TranslateAll = true
default:
return nil, c.Errf("unknown property '%s'", c.Val())
}
}
}
return dns64, nil
}
func parsePrefix(c *caddy.Controller, addr string) (*net.IPNet, error) {
_, pref, err := net.ParseCIDR(addr)
if err != nil {
return nil, err
}
// Test for valid prefix
n, total := pref.Mask.Size()
if total != 128 {
return nil, c.Errf("invalid netmask %d IPv6 address: %q", total, pref)
}
if n%8 != 0 || n < 32 || n > 96 {
return nil, c.Errf("invalid prefix length %q", pref)
}
return pref, nil
}
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