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package file
import (
"fmt"
"log"
"net"
"github.com/coredns/coredns/plugin/pkg/rcode"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
)
// isNotify checks if state is a notify message and if so, will *also* check if it
// is from one of the configured masters. If not it will not be a valid notify
// message. If the zone z is not a secondary zone the message will also be ignored.
func (z *Zone) isNotify(state request.Request) bool {
if state.Req.Opcode != dns.OpcodeNotify {
return false
}
if len(z.TransferFrom) == 0 {
return false
}
// If remote IP matches we accept.
remote := state.IP()
for _, f := range z.TransferFrom {
from, _, err := net.SplitHostPort(f)
if err != nil {
continue
}
if from == remote {
return true
}
}
return false
}
// Notify will send notifies to all configured TransferTo IP addresses.
func (z *Zone) Notify() {
go notify(z.origin, z.TransferTo)
}
// notify sends notifies to the configured remote servers. It will try up to three times
// before giving up on a specific remote. We will sequentially loop through "to"
// until they all have replied (or have 3 failed attempts).
func notify(zone string, to []string) error {
m := new(dns.Msg)
m.SetNotify(zone)
c := new(dns.Client)
for _, t := range to {
if t == "*" {
continue
}
if err := notifyAddr(c, m, t); err != nil {
log.Print("[ERROR] " + err.Error())
} else {
log.Printf("[INFO] Sent notify for zone %q to %q", zone, t)
}
}
return nil
}
func notifyAddr(c *dns.Client, m *dns.Msg, s string) error {
var err error
code := dns.RcodeServerFailure
for i := 0; i < 3; i++ {
ret, _, err := c.Exchange(m, s)
if err != nil {
continue
}
code = ret.Rcode
if code == dns.RcodeSuccess {
return nil
}
}
if err != nil {
return fmt.Errorf("notify for zone %q was not accepted by %q: %q", m.Question[0].Name, s, err)
}
return fmt.Errorf("notify for zone %q was not accepted by %q: rcode was %q", m.Question[0].Name, s, rcode.ToString(code))
}
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