Guard against a bad advertise address

consul/config.go

@@ -5,6 +5,7 @@ import (
 	"github.com/hashicorp/raft"
 	"github.com/hashicorp/serf/serf"
 	"io"
+	"net"
 	"os"
 )
 
@@ -39,6 +40,12 @@ type Config struct {
 	// by the WAN and LAN
 	RPCAddr string
 
+	// RPCAdvertise is the address that is advertised to other nodes for
+	// the RPC endpoint. This can differ from the RPC address, if for example
+	// the RPCAddr is unspecified "0.0.0.0:8300", but this address must be
+	// reachable
+	RPCAdvertise net.Addr
+
 	// SerfLANConfig is the configuration for the intra-dc serf
 	SerfLANConfig *serf.Config
 

consul/server.go

@@ -233,7 +233,26 @@ func (s *Server) setupRPC() error {
 		return err
 	}
 	s.rpcListener = list
-	s.raftLayer = NewRaftLayer(s.rpcListener.Addr())
+
+	var advertise net.Addr
+	if s.config.RPCAdvertise != nil {
+		advertise = s.config.RPCAdvertise
+	} else {
+		advertise = s.rpcListener.Addr()
+	}
+
+	// Verify that we have a usable advertise address
+	addr, ok := advertise.(*net.TCPAddr)
+	if !ok {
+		list.Close()
+		return fmt.Errorf("RPC advertise address is not a TCP Address: %v", addr)
+	}
+	if addr.IP.IsUnspecified() {
+		list.Close()
+		return fmt.Errorf("RPC advertise address is not advertisable: %v", addr)
+	}
+
+	s.raftLayer = NewRaftLayer(advertise)
 	go s.listen()
 	return nil
 }