Example #1
0
// SRVRecords returns SRV records from etcd.
// If the Target is not an name but an IP address, an name is created .
func (s *server) SRVRecords(q dns.Question, name string, bufsize uint16, dnssec bool) (records []dns.RR, extra []dns.RR, err error) {
	path, star := msg.PathWithWildcard(name)
	r, err := get(s.client, path, true)
	if err != nil {
		return nil, nil, err
	}
	if !r.Node.Dir { // single element
		serv := new(msg.Service)
		if err := json.Unmarshal([]byte(r.Node.Value), serv); err != nil {
			s.config.log.Infof("failed to parse json: %s", err.Error())
			return nil, nil, err
		}
		ip := net.ParseIP(serv.Host)
		ttl := s.calculateTtl(r.Node, serv)
		if serv.Priority == 0 {
			serv.Priority = int(s.config.Priority)
		}
		serv.Key = r.Node.Key
		serv.Ttl = ttl
		switch {
		case ip == nil:
			srv := serv.NewSRV(q.Name, uint16(100))
			records = append(records, srv)
			if !dns.IsSubDomain(s.config.Domain, srv.Target) {
				m1, e1 := s.Lookup(srv.Target, dns.TypeA, bufsize, dnssec)
				if e1 == nil {
					extra = append(extra, m1.Answer...)
				}
				m1, e1 = s.Lookup(srv.Target, dns.TypeAAAA, bufsize, dnssec)
				if e1 == nil {
					// If we have seen CNAME's we *assume* that they already added.
					for _, a := range m1.Answer {
						if _, ok := a.(*dns.CNAME); !ok {
							extra = append(extra, a)
						}
					}
				}
			}
		case ip.To4() != nil:
			serv.Host = msg.Domain(serv.Key)
			records = append(records, serv.NewSRV(q.Name, uint16(100)))
			extra = append(extra, serv.NewA(serv.Host, ip.To4()))
		case ip.To4() == nil:
			serv.Host = msg.Domain(serv.Key)
			records = append(records, serv.NewSRV(q.Name, uint16(100)))
			extra = append(extra, serv.NewAAAA(serv.Host, ip.To16()))
		}
		return records, extra, nil
	}

	sx, err := s.loopNodes(&r.Node.Nodes, strings.Split(msg.Path(name), "/"), star, nil)
	if err != nil || len(sx) == 0 {
		return nil, nil, err
	}
	// Looping twice to get the right weight vs priority
	w := make(map[int]int)
	for _, serv := range sx {
		weight := 100
		if serv.Weight != 0 {
			weight = serv.Weight
		}
		if _, ok := w[serv.Priority]; !ok {
			w[serv.Priority] = weight
			continue
		}
		w[serv.Priority] += weight
	}
	lookup := make(map[string]bool)
	for _, serv := range sx {
		w1 := 100.0 / float64(w[serv.Priority])
		if serv.Weight == 0 {
			w1 *= 100
		} else {
			w1 *= float64(serv.Weight)
		}
		weight := uint16(math.Floor(w1))
		ip := net.ParseIP(serv.Host)
		switch {
		case ip == nil:
			srv := serv.NewSRV(q.Name, weight)
			records = append(records, srv)
			if _, ok := lookup[srv.Target]; !ok {
				if !dns.IsSubDomain(s.config.Domain, srv.Target) {
					m1, e1 := s.Lookup(srv.Target, dns.TypeA, bufsize, dnssec)
					if e1 == nil {
						extra = append(extra, m1.Answer...)
					}
					m1, e1 = s.Lookup(srv.Target, dns.TypeAAAA, bufsize, dnssec)
					if e1 == nil {
						// If we have seen CNAME's we *assume* that they are already added.
						for _, a := range m1.Answer {
							if _, ok := a.(*dns.CNAME); !ok {
								extra = append(extra, a)
							}
						}
					}
				}
			}
			lookup[srv.Target] = true
		case ip.To4() != nil:
			serv.Host = msg.Domain(serv.Key)
			records = append(records, serv.NewSRV(q.Name, weight))
			extra = append(extra, serv.NewA(serv.Host, ip.To4()))
		case ip.To4() == nil:
			serv.Host = msg.Domain(serv.Key)
			records = append(records, serv.NewSRV(q.Name, weight))
			extra = append(extra, serv.NewAAAA(serv.Host, ip.To16()))
		}
	}
	return records, extra, nil
}