Add NodeIdHex config option

dht/dht.go

@@ -40,6 +40,12 @@ type transactionKey struct {
 type ServerConfig struct {
 	// Listen address. Used if Conn is nil.
 	Addr string
+
+	// Set NodeId Manually. Caller must ensure that, if NodeId does not
+	// conform to DHT Security Extensions, that NoSecurity is also set. This
+	// should be given as a HEX string.
+	NodeIdHex string
+
 	Conn net.PacketConn
 	// Don't respond to queries from other nodes.
 	Passive bool

dht/dht_test.go

@@ -184,6 +184,22 @@ func TestServerDefaultNodeIdSecure(t *testing.T) {
 	}
 }
 
+func TestServerCustomNodeId(t *testing.T) {
+	customId := "5a3ce1c14e7a08645677bbd1cfe7d8f956d53256"
+	id, err := hex.DecodeString(customId)
+	assert.NoError(t, err)
+	// How to test custom *secure* Id when tester computers will have
+	// different Ids? Generate custom ids for local IPs and use
+	// mini-Id?
+	s, err := NewServer(&ServerConfig{
+		NodeIdHex:          customId,
+		NoDefaultBootstrap: true,
+	})
+	require.NoError(t, err)
+	defer s.Close()
+	assert.Equal(t, string(id), s.ID())
+}
+
 func TestAnnounceTimeout(t *testing.T) {
 	s, err := NewServer(&ServerConfig{
 		BootstrapNodes: []string{"1.2.3.4:5"},

dht/server.go

@@ -3,6 +3,7 @@ package dht
 import (
 	"crypto"
 	"encoding/binary"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"io"
@@ -85,6 +86,14 @@ func NewServer(c *ServerConfig) (s *Server, err error) {
 		}
 	}
 	s.bootstrapNodes = c.BootstrapNodes
+	if c.NodeIdHex != "" {
+		var rawID []byte
+		rawID, err = hex.DecodeString(c.NodeIdHex)
+		if err != nil {
+			return
+		}
+		s.id = string(rawID)
+	}
 	err = s.init()
 	if err != nil {
 		return