net: make parsePort as a function

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6256059

src/pkg/net/ipsock.go

@@ -129,17 +129,10 @@ func hostPortToIP(net, hostport string) (ip IP, iport int, err error) {
 		}
 	}
 
-	p, i, ok := dtoi(port, 0)
-	if !ok || i != len(port) {
-		p, err = LookupPort(net, port)
-		if err != nil {
-			return nil, 0, err
-		}
-	}
-	if p < 0 || p > 0xFFFF {
-		return nil, 0, &AddrError{"invalid port", port}
+	p, err := parsePort(net, port)
+	if err != nil {
+		return nil, 0, err
 	}
 
 	return addr, p, nil
-
 }

src/pkg/net/port.go

-// Copyright 2009 The Go Authors. All rights reserved.
+// Copyright 2012 The Go Authors.  All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin freebsd linux netbsd openbsd
-
-// Read system port mappings from /etc/services
+// Network service port manipulations
 
 package net
 
-import "sync"
-
-var services map[string]map[string]int
-var servicesError error
-var onceReadServices sync.Once
-
-func readServices() {
-	services = make(map[string]map[string]int)
-	var file *file
-	if file, servicesError = open("/etc/services"); servicesError != nil {
-		return
-	}
-	for line, ok := file.readLine(); ok; line, ok = file.readLine() {
-		// "http 80/tcp www www-http # World Wide Web HTTP"
-		if i := byteIndex(line, '#'); i >= 0 {
-			line = line[0:i]
-		}
-		f := getFields(line)
-		if len(f) < 2 {
-			continue
-		}
-		portnet := f[1] // "tcp/80"
-		port, j, ok := dtoi(portnet, 0)
-		if !ok || port <= 0 || j >= len(portnet) || portnet[j] != '/' {
-			continue
-		}
-		netw := portnet[j+1:] // "tcp"
-		m, ok1 := services[netw]
-		if !ok1 {
-			m = make(map[string]int)
-			services[netw] = m
-		}
-		for i := 0; i < len(f); i++ {
-			if i != 1 { // f[1] was port/net
-				m[f[i]] = port
-			}
+// parsePort parses port as a network service port number for both
+// TCP and UDP.
+func parsePort(net, port string) (int, error) {
+	p, i, ok := dtoi(port, 0)
+	if !ok || i != len(port) {
+		var err error
+		p, err = LookupPort(net, port)
+		if err != nil {
+			return 0, err
 		}
 	}
-	file.close()
-}
-
-// goLookupPort is the native Go implementation of LookupPort.
-func goLookupPort(network, service string) (port int, err error) {
-	onceReadServices.Do(readServices)
-
-	switch network {
-	case "tcp4", "tcp6":
-		network = "tcp"
-	case "udp4", "udp6":
-		network = "udp"
-	}
-
-	if m, ok := services[network]; ok {
-		if port, ok = m[service]; ok {
-			return
-		}
+	if p < 0 || p > 0xFFFF {
+		return 0, &AddrError{"invalid port", port}
 	}
-	return 0, &AddrError{"unknown port", network + "/" + service}
+	return p, nil
 }

src/pkg/net/port_unix.go

+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin freebsd linux netbsd openbsd
+
+// Read system port mappings from /etc/services
+
+package net
+
+import "sync"
+
+var services map[string]map[string]int
+var servicesError error
+var onceReadServices sync.Once
+
+func readServices() {
+	services = make(map[string]map[string]int)
+	var file *file
+	if file, servicesError = open("/etc/services"); servicesError != nil {
+		return
+	}
+	for line, ok := file.readLine(); ok; line, ok = file.readLine() {
+		// "http 80/tcp www www-http # World Wide Web HTTP"
+		if i := byteIndex(line, '#'); i >= 0 {
+			line = line[0:i]
+		}
+		f := getFields(line)
+		if len(f) < 2 {
+			continue
+		}
+		portnet := f[1] // "tcp/80"
+		port, j, ok := dtoi(portnet, 0)
+		if !ok || port <= 0 || j >= len(portnet) || portnet[j] != '/' {
+			continue
+		}
+		netw := portnet[j+1:] // "tcp"
+		m, ok1 := services[netw]
+		if !ok1 {
+			m = make(map[string]int)
+			services[netw] = m
+		}
+		for i := 0; i < len(f); i++ {
+			if i != 1 { // f[1] was port/net
+				m[f[i]] = port
+			}
+		}
+	}
+	file.close()
+}
+
+// goLookupPort is the native Go implementation of LookupPort.
+func goLookupPort(network, service string) (port int, err error) {
+	onceReadServices.Do(readServices)
+
+	switch network {
+	case "tcp4", "tcp6":
+		network = "tcp"
+	case "udp4", "udp6":
+		network = "udp"
+	}
+
+	if m, ok := services[network]; ok {
+		if port, ok = m[service]; ok {
+			return
+		}
+	}
+	return 0, &AddrError{"unknown port", network + "/" + service}
+}