1 files changed, 75 insertions, 9 deletions
diff --git a/libgo/go/net/lookup_unix.go b/libgo/go/net/lookup_unix.go
index 8f5e66212b3..6e79295a948 100644
--- a/libgo/go/net/lookup_unix.go
+++ b/libgo/go/net/lookup_unix.go
@@ -2,12 +2,56 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin freebsd linux openbsd
+
 package net
 
 import (
 	"os"
+	"sync"
+)
+
+var (
+	protocols         map[string]int
+	onceReadProtocols sync.Once
 )
 
+// readProtocols loads contents of /etc/protocols into protocols map
+// for quick access.
+func readProtocols() {
+	protocols = make(map[string]int)
+	if file, err := open("/etc/protocols"); err == nil {
+		for line, ok := file.readLine(); ok; line, ok = file.readLine() {
+			// tcp    6   TCP    # transmission control protocol
+			if i := byteIndex(line, '#'); i >= 0 {
+				line = line[0:i]
+			}
+			f := getFields(line)
+			if len(f) < 2 {
+				continue
+			}
+			if proto, _, ok := dtoi(f[1], 0); ok {
+				protocols[f[0]] = proto
+				for _, alias := range f[2:] {
+					protocols[alias] = proto
+				}
+			}
+		}
+		file.close()
+	}
+}
+
+// lookupProtocol looks up IP protocol name in /etc/protocols and
+// returns correspondent protocol number.
+func lookupProtocol(name string) (proto int, err os.Error) {
+	onceReadProtocols.Do(readProtocols)
+	proto, found := protocols[name]
+	if !found {
+		return 0, os.NewError("unknown IP protocol specified: " + name)
+	}
+	return
+}
+
 // LookupHost looks up the given host using the local resolver.
 // It returns an array of that host's addresses.
 func LookupHost(host string) (addrs []string, err os.Error) {
@@ -50,12 +94,21 @@ func LookupCNAME(name string) (cname string, err os.Error) {
 }
 
 // LookupSRV tries to resolve an SRV query of the given service,
-// protocol, and domain name, as specified in RFC 2782. In most cases
-// the proto argument can be the same as the corresponding
-// Addr.Network(). The returned records are sorted by priority 
-// and randomized by weight within a priority.
+// protocol, and domain name.  The proto is "tcp" or "udp".
+// The returned records are sorted by priority and randomized
+// by weight within a priority.
+//
+// LookupSRV constructs the DNS name to look up following RFC 2782.
+// That is, it looks up _service._proto.name.  To accommodate services
+// publishing SRV records under non-standard names, if both service
+// and proto are empty strings, LookupSRV looks up name directly.
 func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err os.Error) {
-	target := "_" + service + "._" + proto + "." + name
+	var target string
+	if service == "" && proto == "" {
+		target = name
+	} else {
+		target = "_" + service + "._" + proto + "." + name
+	}
 	var records []dnsRR
 	cname, records, err = lookup(target, dnsTypeSRV)
 	if err != nil {
@@ -72,19 +125,32 @@ func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err os.
 
 // LookupMX returns the DNS MX records for the given domain name sorted by preference.
 func LookupMX(name string) (mx []*MX, err os.Error) {
-	_, rr, err := lookup(name, dnsTypeMX)
+	_, records, err := lookup(name, dnsTypeMX)
 	if err != nil {
 		return
 	}
-	mx = make([]*MX, len(rr))
-	for i := range rr {
-		r := rr[i].(*dnsRR_MX)
+	mx = make([]*MX, len(records))
+	for i, rr := range records {
+		r := rr.(*dnsRR_MX)
 		mx[i] = &MX{r.Mx, r.Pref}
 	}
 	byPref(mx).sort()
 	return
 }
 
+// LookupTXT returns the DNS TXT records for the given domain name.
+func LookupTXT(name string) (txt []string, err os.Error) {
+	_, records, err := lookup(name, dnsTypeTXT)
+	if err != nil {
+		return
+	}
+	txt = make([]string, len(records))
+	for i, r := range records {
+		txt[i] = r.(*dnsRR_TXT).Txt
+	}
+	return
+}
+
 // LookupAddr performs a reverse lookup for the given address, returning a list
 // of names mapping to that address.
 func LookupAddr(addr string) (name []string, err os.Error) {