/*
* sendRequest() - send a DNS query
*/
func sendRequest(ctx *Context, m *dns.Msg, transport string, timeout time.Duration) (response *dns.Msg, rtt time.Duration, err error) {
c := new(dns.Client)
c.Timeout = timeout
c.Net = transport // "udp" or "tcp"
response, rtt, err = c.Exchange(m, addressString(ctx.server, ctx.port))
return
}
func digester(server string, done <-chan struct{}, names <-chan string, output chan<- DNSResponse) {
for targetName := range names {
message := new(dns.Msg)
client := new(dns.Client)
client.Timeout = 10 * 1e9
message.SetQuestion(targetName, dns.TypeA)
response, _, err := client.Exchange(message, server+":53")
// retry errors.
if err != nil {
response, _, err = client.Exchange(message, server+":53")
}
resp := makeDNSResponse(targetName, response, err)
select {
case output <- *resp:
case <-done:
return
}
}
}