Parse upstream URLs with net/url

This allows us to ignore the path part of the URL. This is preliminary
work for unix URLs.

upstream.go

@@ -10,6 +10,7 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"net/url"
 	"strconv"
 	"strings"
 	"time"
@@ -80,31 +81,30 @@ type upstreamConn struct {
 func connectToUpstream(network *network) (*upstreamConn, error) {
 	logger := &prefixLogger{network.user.srv.Logger, fmt.Sprintf("upstream %q: ", network.Addr)}
 
-	var scheme string
-	var addr string
-
-	addrParts := strings.SplitN(network.Addr, "://", 2)
-	if len(addrParts) == 2 {
-		scheme = addrParts[0]
-		addr = addrParts[1]
-	} else {
-		scheme = "ircs"
-		addr = addrParts[0]
-	}
-
 	dialer := net.Dialer{Timeout: connectTimeout}
 
+	s := network.Addr
+	if !strings.Contains(s, "://") {
+		// This is a raw domain name, make it an URL with the default scheme
+		s = "ircs://" + s
+	}
+
+	u, err := url.Parse(s)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse upstream server URL: %v", err)
+	}
+
 	var netConn net.Conn
-	var err error
+	switch u.Scheme {
-	switch scheme {
 	case "ircs":
+		addr := u.Host
 		if _, _, err := net.SplitHostPort(addr); err != nil {
 			addr = addr + ":6697"
 		}
 
 		logger.Printf("connecting to TLS server at address %q", addr)
 
-		var cfg *tls.Config
+		var tlsConfig *tls.Config
 		if network.SASL.Mechanism == "EXTERNAL" {
 			if network.SASL.External.CertBlob == nil {
 				return nil, fmt.Errorf("missing certificate for authentication")
@@ -116,7 +116,7 @@ func connectToUpstream(network *network) (*upstreamConn, error) {
 			if err != nil {
 				return nil, fmt.Errorf("failed to parse private key: %v", err)
 			}
-			cfg = &tls.Config{
+			tlsConfig = &tls.Config{
 				Certificates: []tls.Certificate{
 					{
 						Certificate: [][]byte{network.SASL.External.CertBlob},
@@ -127,19 +127,23 @@ func connectToUpstream(network *network) (*upstreamConn, error) {
 			logger.Printf("using TLS client certificate %x", sha256.Sum256(network.SASL.External.CertBlob))
 		}
 
-		netConn, err = tls.DialWithDialer(&dialer, "tcp", addr, cfg)
+		netConn, err = tls.DialWithDialer(&dialer, "tcp", addr, tlsConfig)
+		if err != nil {
+			return nil, fmt.Errorf("failed to dial %q: %v", addr, err)
+		}
 	case "irc+insecure":
+		addr := u.Host
 		if _, _, err := net.SplitHostPort(addr); err != nil {
 			addr = addr + ":6667"
 		}
 
 		logger.Printf("connecting to plain-text server at address %q", addr)
 		netConn, err = dialer.Dial("tcp", addr)
+		if err != nil {
+			return nil, fmt.Errorf("failed to dial %q: %v", addr, err)
+		}
 	default:
-		return nil, fmt.Errorf("failed to dial %q: unknown scheme: %v", addr, scheme)
+		return nil, fmt.Errorf("failed to dial %q: unknown scheme: %v", network.Addr, u.Scheme)
-	}
-	if err != nil {
-		return nil, fmt.Errorf("failed to dial %q: %v", addr, err)
 	}
 
 	uc := &upstreamConn{
@@ -156,7 +160,6 @@ func connectToUpstream(network *network) (*upstreamConn, error) {
 		pendingLISTDownstreamSet: make(map[uint64]struct{}),
 		messageLoggers:           make(map[string]*messageLogger),
 	}
-
 	return uc, nil
 }