fix host:port joining for ipv6 listen addresses

client/cmd/dexc/config.go

@@ -5,6 +5,7 @@ package main
 
 import (
 	"fmt"
+	"net"
 	"os"
 	"os/user"
 	"path/filepath"
@@ -184,10 +185,10 @@ func configure() (*Config, error) {
 	// If web or RPC server addresses not set, use network specific
 	// defaults
 	if cfg.WebAddr == "" {
-		cfg.WebAddr = defaultHost + ":" + defaultWebPort
+		cfg.WebAddr = net.JoinHostPort(defaultHost, defaultWebPort)
 	}
 	if cfg.RPCAddr == "" {
-		cfg.RPCAddr = defaultHost + ":" + defaultRPCPort
+		cfg.RPCAddr = net.JoinHostPort(defaultHost, defaultRPCPort)
 	}
 
 	if cfg.RPCCert == "" {

client/core/core.go

@@ -946,7 +946,8 @@ func addrHost(addr string) (string, error) {
 		// Any address with no colons is appended with the default port.
 		var addrErr *net.AddrError
 		if errors.As(splitErr, &addrErr) && addrErr.Err == missingPort {
-			return addr + ":" + defaultDEXPort, nil
+			host = strings.Trim(addrErr.Addr, "[]") // JoinHostPort expects no brackets for ipv6 hosts
+			return net.JoinHostPort(host, defaultDEXPort), nil
 		}
 		// These are addresses with at least one colon in an unexpected
 		// position.
@@ -958,7 +959,7 @@ func addrHost(addr string) (string, error) {
 		host, port = a.Hostname(), a.Port()
 		// If the address parses but there is no port, append the default port.
 		if port == "" {
-			return host + ":" + defaultDEXPort, nil
+			return net.JoinHostPort(host, defaultDEXPort), nil
 		}
 	}
 	// We have a port but no host. Replace with localhost.

client/core/core_test.go

@@ -4168,6 +4168,10 @@ func TestAddrHost(t *testing.T) {
 		name: "scheme, host, and port",
 		addr: "https://localhost:5758",
 		want: "localhost:5758",
+	}, {
+		name: "scheme, ipv6 host, and port",
+		addr: "https://[::1]:5758",
+		want: "[::1]:5758",
 	}, {
 		name: "host and port",
 		addr: "localhost:5758",

server/cmd/dcrdex/config.go

@@ -4,6 +4,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"net"
 	"os"
@@ -254,26 +255,30 @@ func parseAndSetDebugLevels(debugLevel string, UTC bool) (*dex.LoggerMaker, erro
 	return lm, nil
 }
 
+const missingPort = "missing port in address"
+
 // normalizeNetworkAddress checks for a valid local network address format and
 // adds default host and port if not present. Invalidates addresses that include
 // a protocol identifier.
 func normalizeNetworkAddress(a, defaultHost, defaultPort string) (string, error) {
 	if strings.Contains(a, "://") {
-		return a, fmt.Errorf("Address %s contains a protocol identifier, which is not allowed", a)
+		return a, fmt.Errorf("address %s contains a protocol identifier, which is not allowed", a)
 	}
 	if a == "" {
-		return defaultHost + ":" + defaultPort, nil
+		return net.JoinHostPort(defaultHost, defaultPort), nil
 	}
 	host, port, err := net.SplitHostPort(a)
 	if err != nil {
-		if strings.Contains(err.Error(), "missing port in address") {
-			normalized := a + ":" + defaultPort
+		var addrErr *net.AddrError
+		if errors.As(err, &addrErr) && addrErr.Err == missingPort {
+			host = strings.Trim(addrErr.Addr, "[]") // JoinHostPort expects no brackets for ipv6 hosts
+			normalized := net.JoinHostPort(host, defaultPort)
 			host, port, err = net.SplitHostPort(normalized)
 			if err != nil {
-				return a, fmt.Errorf("Unable to address %s after port resolution: %v", normalized, err)
+				return a, fmt.Errorf("unable to address %s after port resolution: %w", normalized, err)
 			}
 		} else {
-			return a, fmt.Errorf("Unable to normalize address %s: %v", a, err)
+			return a, fmt.Errorf("unable to normalize address %s: %w", a, err)
 		}
 	}
 	if host == "" {
@@ -282,7 +287,7 @@ func normalizeNetworkAddress(a, defaultHost, defaultPort string) (string, error)
 	if port == "" {
 		port = defaultPort
 	}
-	return host + ":" + port, nil
+	return net.JoinHostPort(host, port), nil
 }
 
 // loadConfig initializes and parses the config using a config file and command

server/cmd/dcrdex/config_test.go

@@ -0,0 +1,52 @@
+// This code is available on the terms of the project LICENSE.md file,
+// also available online at https://blueoakcouncil.org/license/1.0.0.
+
+package main
+
+import "testing"
+
+const (
+	defaultHost = "127.0.0.1"
+	defaultPort = "17232"
+)
+
+func Test_normalizeNetworkAddress(t *testing.T) {
+	tests := []struct {
+		listen  string
+		want    string
+		wantErr bool
+	}{
+		{
+			listen: "[::1]",
+			want:   "[::1]:17232",
+		},
+		{
+			listen: "[::]:",
+			want:   "[::]:17232",
+		},
+		{
+			listen: "",
+			want:   "127.0.0.1:17232",
+		},
+		{
+			listen: "127.0.0.2",
+			want:   "127.0.0.2:17232",
+		},
+		{
+			listen: ":7222",
+			want:   "127.0.0.1:7222",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.listen, func(t *testing.T) {
+			got, err := normalizeNetworkAddress(tt.listen, defaultHost, defaultPort)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("normalizeNetworkAddress() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("normalizeNetworkAddress() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}