Example #1
0
// NSRecords returns NS records from etcd.
func (s *server) NSRecords(q dns.Question, name string) (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)
		serv.Key = r.Node.Key
		serv.Ttl = ttl
		switch {
		case ip == nil:
			return nil, nil, fmt.Errorf("NS record must be an IP address")
		case ip.To4() != nil:
			serv.Host = msg.Domain(serv.Key)
			records = append(records, serv.NewNS(q.Name, serv.Host))
			extra = append(extra, serv.NewA(serv.Host, ip.To4()))
		case ip.To4() == nil:
			serv.Host = msg.Domain(serv.Key)
			records = append(records, serv.NewNS(q.Name, serv.Host))
			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
	}
	for _, serv := range sx {
		ip := net.ParseIP(serv.Host)
		switch {
		case ip == nil:
			return nil, nil, fmt.Errorf("NS record must be an IP address")
		case ip.To4() != nil:
			serv.Host = msg.Domain(serv.Key)
			records = append(records, serv.NewNS(q.Name, serv.Host))
			extra = append(extra, serv.NewA(serv.Host, ip.To4()))
		case ip.To4() == nil:
			serv.Host = msg.Domain(serv.Key)
			records = append(records, serv.NewNS(q.Name, serv.Host))
			extra = append(extra, serv.NewAAAA(serv.Host, ip.To16()))
		}
	}
	return records, extra, nil
}
Example #2
0
func (g *Backend) decode(n *etcd.Node) (*msg.Service, error) {
	serv := new(msg.Service)
	if err := json.Unmarshal([]byte(n.Value), serv); err != nil {
		return nil, err
	}

	serv.Key = n.Key
	serv.Ttl = g.calculateTtl(n, serv)
	if serv.Priority == 0 {
		serv.Priority = int(g.config.Priority)
	}

	return serv, nil
}
Example #3
0
// loopNodes recursively loops through the nodes and returns all the values. The nodes' keyname
// will be match against any wildcards when star is true.
func (g *Backend) loopNodes(ns []*etcd.Node, nameParts []string, star bool, bx map[bareService]bool) (sx []msg.Service, err error) {
	if bx == nil {
		bx = make(map[bareService]bool)
	}
Nodes:
	for _, n := range ns {
		if n.Dir {
			nodes, err := g.loopNodes(n.Nodes, nameParts, star, bx)
			if err != nil {
				return nil, err
			}
			sx = append(sx, nodes...)
			continue
		}
		if star {
			keyParts := strings.Split(n.Key, "/")
			for i, n := range nameParts {
				if i > len(keyParts)-1 {
					// name is longer than key
					continue Nodes
				}
				if n == "*" || n == "any" {
					continue
				}
				if keyParts[i] != n {
					continue Nodes
				}
			}
		}
		serv := new(msg.Service)
		if err := json.Unmarshal([]byte(n.Value), serv); err != nil {
			return nil, err
		}
		b := bareService{serv.Host, serv.Port, serv.Priority, serv.Weight, serv.Text}
		if _, ok := bx[b]; ok {
			continue
		}
		bx[b] = true

		serv.Key = n.Key
		serv.Ttl = g.calculateTtl(n, serv)
		if serv.Priority == 0 {
			serv.Priority = int(g.config.Priority)
		}
		sx = append(sx, *serv)
	}
	return sx, nil
}
Example #4
0
File: etcd3.go Project: CMGS/skydns
func (g *Backendv3) loopNodes(kv []*mvccpb.KeyValue, nameParts []string, star bool, bx map[bareService]bool) (sx []msg.Service, err error) {
	if bx == nil {
		bx = make(map[bareService]bool)
	}
Nodes:
	for _, item := range kv {

		if star {
			s := string(item.Key[:])
			keyParts := strings.Split(s, "/")
			for i, n := range nameParts {
				if i > len(keyParts)-1 {
					continue Nodes
				}
				if n == "*" || n == "any" {
					continue
				}
				if keyParts[i] != n {
					continue Nodes
				}
			}
		}

		serv := new(msg.Service)
		if err := json.Unmarshal(item.Value, serv); err != nil {
			return nil, err
		}

		b := bareService{serv.Host,
			serv.Port,
			serv.Priority,
			serv.Weight,
			serv.Text}

		bx[b] = true
		serv.Key = string(item.Key)
		//TODO: another call (LeaseRequest) for TTL when RPC in etcdv3 is ready
		serv.Ttl = g.calculateTtl(item, serv)

		if serv.Priority == 0 {
			serv.Priority = int(g.config.Priority)
		}

		sx = append(sx, *serv)
	}
	return sx, nil
}
Example #5
0
func (s *server) CNAMERecords(q dns.Question, name string) (records []dns.RR, err error) {
	path, _ := msg.PathWithWildcard(name) // no wildcards here
	r, err := get(s.client, path, true)
	if err != nil {
		return nil, err
	}
	if !r.Node.Dir {
		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, err
		}
		ip := net.ParseIP(serv.Host)
		ttl := s.calculateTtl(r.Node, serv)
		serv.Key = r.Node.Key
		serv.Ttl = ttl
		if ip == nil {
			records = append(records, serv.NewCNAME(q.Name, dns.Fqdn(serv.Host)))
		}
	}
	return records, nil
}
Example #6
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
}
Example #7
0
func (s *server) AddressRecords(q dns.Question, name string, previousRecords []dns.RR) (records []dns.RR, err error) {
	path, star := msg.PathWithWildcard(name)
	r, err := get(s.client, path, true)
	if err != nil {
		return 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, err
		}
		ip := net.ParseIP(serv.Host)
		ttl := s.calculateTtl(r.Node, serv)
		serv.Ttl = ttl
		serv.Key = r.Node.Key
		switch {
		case ip == nil:
			// Try to resolve as CNAME if it's not an IP.
			newRecord := serv.NewCNAME(q.Name, dns.Fqdn(serv.Host))
			if len(previousRecords) > 7 {
				s.config.log.Errorf("CNAME lookup limit of 8 exceeded for %s", newRecord)
				return nil, fmt.Errorf("exceeded CNAME lookup limit")
			}
			if s.isDuplicateCNAME(newRecord, previousRecords) {
				s.config.log.Errorf("CNAME loop detected for record %s", newRecord)
				return nil, fmt.Errorf("detected CNAME loop")
			}

			records = append(records, newRecord)
			nextRecords, err := s.AddressRecords(dns.Question{Name: dns.Fqdn(serv.Host), Qtype: q.Qtype, Qclass: q.Qclass}, strings.ToLower(dns.Fqdn(serv.Host)), append(previousRecords, newRecord))
			if err != nil {
				// This means we can not complete the CNAME, this is OK, but
				// if we return an error this will trigger an NXDOMAIN.
				// We also don't want to return the CNAME, because of the
				// no other data rule. So return nothing and let NODATA
				// kick in (via a hack).
				return records, fmt.Errorf("incomplete CNAME chain")
			}
			records = append(records, nextRecords...)
		case ip.To4() != nil && q.Qtype == dns.TypeA:
			records = append(records, serv.NewA(q.Name, ip.To4()))
		case ip.To4() == nil && q.Qtype == dns.TypeAAAA:
			records = append(records, serv.NewAAAA(q.Name, ip.To16()))
		}
		return records, nil
	}
	nodes, err := s.loopNodes(&r.Node.Nodes, strings.Split(msg.Path(name), "/"), star, nil)
	if err != nil {
		s.config.log.Infof("failed to parse json: %s", err.Error())
		return nil, err
	}
	for _, serv := range nodes {
		ip := net.ParseIP(serv.Host)
		switch {
		case ip == nil:
			// TODO: deduplicate with above code
			// Try to resolve as CNAME if it's not an IP.
			newRecord := serv.NewCNAME(q.Name, dns.Fqdn(serv.Host))
			if len(previousRecords) > 7 {
				s.config.log.Errorf("CNAME lookup limit of 8 exceeded for %s", newRecord)
				return nil, fmt.Errorf("exceeded CNAME lookup limit")
			}
			if s.isDuplicateCNAME(newRecord, previousRecords) {
				s.config.log.Errorf("CNAME loop detected for record %s", newRecord)
				return nil, fmt.Errorf("detected CNAME loop")
			}

			records = append(records, newRecord)
			nextRecords, err := s.AddressRecords(dns.Question{Name: dns.Fqdn(serv.Host), Qtype: q.Qtype, Qclass: q.Qclass}, strings.ToLower(dns.Fqdn(serv.Host)), append(previousRecords, newRecord))
			if err != nil {
				// This means we can not complete the CNAME, this is OK, but
				// if we return an error this will trigger an NXDOMAIN.
				// We also don't want to return the CNAME, because of the
				// no other data rule. So return nothing and let NODATA
				// kick in (via a hack).
				return records, fmt.Errorf("incomplete CNAME chain")
			}
			records = append(records, nextRecords...)
		case ip.To4() != nil && q.Qtype == dns.TypeA:
			records = append(records, serv.NewA(q.Name, ip.To4()))
		case ip.To4() == nil && q.Qtype == dns.TypeAAAA:
			records = append(records, serv.NewAAAA(q.Name, ip.To16()))
		}
	}
	if s.config.RoundRobin {
		switch l := len(records); l {
		case 2:
			if dns.Id()%2 == 0 {
				records[0], records[1] = records[1], records[0]
			}
		default:
			// Do a minimum of l swap, maximum of 4l swaps
			for j := 0; j < l*(int(dns.Id())%4+1); j++ {
				q := int(dns.Id()) % l
				p := int(dns.Id()) % l
				if q == p {
					p = (p + 1) % l
				}
				records[q], records[p] = records[p], records[q]
			}
		}
	}
	return records, nil
}