1 files changed, 297 insertions, 0 deletions
diff --git a/src/net/lookup_plan9.go b/src/net/lookup_plan9.go
new file mode 100644
index 000000000..b80ac10e0
--- /dev/null
+++ b/src/net/lookup_plan9.go
@@ -0,0 +1,297 @@
+// Copyright 2011 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.
+
+package net
+
+import (
+	"errors"
+	"os"
+)
+
+func query(filename, query string, bufSize int) (res []string, err error) {
+	file, err := os.OpenFile(filename, os.O_RDWR, 0)
+	if err != nil {
+		return
+	}
+	defer file.Close()
+
+	_, err = file.Seek(0, 0)
+	if err != nil {
+		return
+	}
+	_, err = file.WriteString(query)
+	if err != nil {
+		return
+	}
+	_, err = file.Seek(0, 0)
+	if err != nil {
+		return
+	}
+	buf := make([]byte, bufSize)
+	for {
+		n, _ := file.Read(buf)
+		if n <= 0 {
+			break
+		}
+		res = append(res, string(buf[:n]))
+	}
+	return
+}
+
+func queryCS(net, host, service string) (res []string, err error) {
+	switch net {
+	case "tcp4", "tcp6":
+		net = "tcp"
+	case "udp4", "udp6":
+		net = "udp"
+	}
+	if host == "" {
+		host = "*"
+	}
+	return query(netdir+"/cs", net+"!"+host+"!"+service, 128)
+}
+
+func queryCS1(net string, ip IP, port int) (clone, dest string, err error) {
+	ips := "*"
+	if len(ip) != 0 && !ip.IsUnspecified() {
+		ips = ip.String()
+	}
+	lines, err := queryCS(net, ips, itoa(port))
+	if err != nil {
+		return
+	}
+	f := getFields(lines[0])
+	if len(f) < 2 {
+		return "", "", errors.New("bad response from ndb/cs")
+	}
+	clone, dest = f[0], f[1]
+	return
+}
+
+func queryDNS(addr string, typ string) (res []string, err error) {
+	return query(netdir+"/dns", addr+" "+typ, 1024)
+}
+
+// toLower returns a lower-case version of in. Restricting us to
+// ASCII is sufficient to handle the IP protocol names and allow
+// us to not depend on the strings and unicode packages.
+func toLower(in string) string {
+	for _, c := range in {
+		if 'A' <= c && c <= 'Z' {
+			// Has upper case; need to fix.
+			out := []byte(in)
+			for i := 0; i < len(in); i++ {
+				c := in[i]
+				if 'A' <= c && c <= 'Z' {
+					c += 'a' - 'A'
+				}
+				out[i] = c
+			}
+			return string(out)
+		}
+	}
+	return in
+}
+
+// lookupProtocol looks up IP protocol name and returns
+// the corresponding protocol number.
+func lookupProtocol(name string) (proto int, err error) {
+	lines, err := query(netdir+"/cs", "!protocol="+toLower(name), 128)
+	if err != nil {
+		return 0, err
+	}
+	unknownProtoError := errors.New("unknown IP protocol specified: " + name)
+	if len(lines) == 0 {
+		return 0, unknownProtoError
+	}
+	f := getFields(lines[0])
+	if len(f) < 2 {
+		return 0, unknownProtoError
+	}
+	s := f[1]
+	if n, _, ok := dtoi(s, byteIndex(s, '=')+1); ok {
+		return n, nil
+	}
+	return 0, unknownProtoError
+}
+
+func lookupHost(host string) (addrs []string, err error) {
+	// Use netdir/cs instead of netdir/dns because cs knows about
+	// host names in local network (e.g. from /lib/ndb/local)
+	lines, err := queryCS("net", host, "1")
+	if err != nil {
+		return
+	}
+loop:
+	for _, line := range lines {
+		f := getFields(line)
+		if len(f) < 2 {
+			continue
+		}
+		addr := f[1]
+		if i := byteIndex(addr, '!'); i >= 0 {
+			addr = addr[:i] // remove port
+		}
+		if ParseIP(addr) == nil {
+			continue
+		}
+		// only return unique addresses
+		for _, a := range addrs {
+			if a == addr {
+				continue loop
+			}
+		}
+		addrs = append(addrs, addr)
+	}
+	return
+}
+
+func lookupIP(host string) (ips []IP, err error) {
+	addrs, err := LookupHost(host)
+	if err != nil {
+		return
+	}
+	for _, addr := range addrs {
+		if ip := ParseIP(addr); ip != nil {
+			ips = append(ips, ip)
+		}
+	}
+	return
+}
+
+func lookupPort(network, service string) (port int, err error) {
+	switch network {
+	case "tcp4", "tcp6":
+		network = "tcp"
+	case "udp4", "udp6":
+		network = "udp"
+	}
+	lines, err := queryCS(network, "127.0.0.1", service)
+	if err != nil {
+		return
+	}
+	unknownPortError := &AddrError{"unknown port", network + "/" + service}
+	if len(lines) == 0 {
+		return 0, unknownPortError
+	}
+	f := getFields(lines[0])
+	if len(f) < 2 {
+		return 0, unknownPortError
+	}
+	s := f[1]
+	if i := byteIndex(s, '!'); i >= 0 {
+		s = s[i+1:] // remove address
+	}
+	if n, _, ok := dtoi(s, 0); ok {
+		return n, nil
+	}
+	return 0, unknownPortError
+}
+
+func lookupCNAME(name string) (cname string, err error) {
+	lines, err := queryDNS(name, "cname")
+	if err != nil {
+		return
+	}
+	if len(lines) > 0 {
+		if f := getFields(lines[0]); len(f) >= 3 {
+			return f[2] + ".", nil
+		}
+	}
+	return "", errors.New("bad response from ndb/dns")
+}
+
+func lookupSRV(service, proto, name string) (cname string, addrs []*SRV, err error) {
+	var target string
+	if service == "" && proto == "" {
+		target = name
+	} else {
+		target = "_" + service + "._" + proto + "." + name
+	}
+	lines, err := queryDNS(target, "srv")
+	if err != nil {
+		return
+	}
+	for _, line := range lines {
+		f := getFields(line)
+		if len(f) < 6 {
+			continue
+		}
+		port, _, portOk := dtoi(f[4], 0)
+		priority, _, priorityOk := dtoi(f[3], 0)
+		weight, _, weightOk := dtoi(f[2], 0)
+		if !(portOk && priorityOk && weightOk) {
+			continue
+		}
+		addrs = append(addrs, &SRV{f[5], uint16(port), uint16(priority), uint16(weight)})
+		cname = f[0]
+	}
+	byPriorityWeight(addrs).sort()
+	return
+}
+
+func lookupMX(name string) (mx []*MX, err error) {
+	lines, err := queryDNS(name, "mx")
+	if err != nil {
+		return
+	}
+	for _, line := range lines {
+		f := getFields(line)
+		if len(f) < 4 {
+			continue
+		}
+		if pref, _, ok := dtoi(f[2], 0); ok {
+			mx = append(mx, &MX{f[3], uint16(pref)})
+		}
+	}
+	byPref(mx).sort()
+	return
+}
+
+func lookupNS(name string) (ns []*NS, err error) {
+	lines, err := queryDNS(name, "ns")
+	if err != nil {
+		return
+	}
+	for _, line := range lines {
+		f := getFields(line)
+		if len(f) < 3 {
+			continue
+		}
+		ns = append(ns, &NS{f[2]})
+	}
+	return
+}
+
+func lookupTXT(name string) (txt []string, err error) {
+	lines, err := queryDNS(name, "txt")
+	if err != nil {
+		return
+	}
+	for _, line := range lines {
+		if i := byteIndex(line, '\t'); i >= 0 {
+			txt = append(txt, line[i+1:])
+		}
+	}
+	return
+}
+
+func lookupAddr(addr string) (name []string, err error) {
+	arpa, err := reverseaddr(addr)
+	if err != nil {
+		return
+	}
+	lines, err := queryDNS(arpa, "ptr")
+	if err != nil {
+		return
+	}
+	for _, line := range lines {
+		f := getFields(line)
+		if len(f) < 3 {
+			continue
+		}
+		name = append(name, f[2])
+	}
+	return
+}