Imported Upstream version 59upstream/59

1 files changed, 126 insertions, 0 deletions

diff --git a/src/pkg/net/lookup_unix.go b/src/pkg/net/lookup_unix.go
new file mode 100644
index 000000000..168d3fa6d
--- /dev/null
+++ b/src/pkg/net/lookup_unix.go
@@ -0,0 +1,126 @@
+// 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 (
+	"os"
+	"rand"
+	"sort"
+)
+
+// 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) {
+	addrs, err, ok := cgoLookupHost(host)
+	if !ok {
+		addrs, err = goLookupHost(host)
+	}
+	return
+}
+
+// LookupIP looks up host using the local resolver.
+// It returns an array of that host's IPv4 and IPv6 addresses.
+func LookupIP(host string) (addrs []IP, err os.Error) {
+	addrs, err, ok := cgoLookupIP(host)
+	if !ok {
+		addrs, err = goLookupIP(host)
+	}
+	return
+}
+
+// LookupPort looks up the port for the given network and service.
+func LookupPort(network, service string) (port int, err os.Error) {
+	port, err, ok := cgoLookupPort(network, service)
+	if !ok {
+		port, err = goLookupPort(network, service)
+	}
+	return
+}
+
+// LookupCNAME returns the canonical DNS host for the given name.
+// Callers that do not care about the canonical name can call
+// LookupHost or LookupIP directly; both take care of resolving
+// the canonical name as part of the lookup.
+func LookupCNAME(name string) (cname string, err os.Error) {
+	cname, err, ok := cgoLookupCNAME(name)
+	if !ok {
+		cname, err = goLookupCNAME(name)
+	}
+	return
+}
+
+// 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.
+func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err os.Error) {
+	target := "_" + service + "._" + proto + "." + name
+	var records []dnsRR
+	cname, records, err = lookup(target, dnsTypeSRV)
+	if err != nil {
+		return
+	}
+	addrs = make([]*SRV, len(records))
+	for i, rr := range records {
+		r := rr.(*dnsRR_SRV)
+		addrs[i] = &SRV{r.Target, r.Port, r.Priority, r.Weight}
+	}
+	sort.Sort(byPriorityWeight(addrs))
+	i := 0
+	for j := 1; j < len(addrs); j++ {
+		if addrs[i].Priority != addrs[j].Priority {
+			shuffleSRVByWeight(addrs[i:j])
+			i = j
+		}
+	}
+	shuffleSRVByWeight(addrs[i:len(addrs)])
+	return
+}
+
+// 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)
+	if err != nil {
+		return
+	}
+	mx = make([]*MX, len(rr))
+	for i := range rr {
+		r := rr[i].(*dnsRR_MX)
+		mx[i] = &MX{r.Mx, r.Pref}
+	}
+	// Shuffle the records to match RFC 5321 when sorted
+	for i := range mx {
+		j := rand.Intn(i + 1)
+		mx[i], mx[j] = mx[j], mx[i]
+	}
+	sort.Sort(byPref(mx))
+	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) {
+	name = lookupStaticAddr(addr)
+	if len(name) > 0 {
+		return
+	}
+	var arpa string
+	arpa, err = reverseaddr(addr)
+	if err != nil {
+		return
+	}
+	var records []dnsRR
+	_, records, err = lookup(arpa, dnsTypePTR)
+	if err != nil {
+		return
+	}
+	name = make([]string, len(records))
+	for i := range records {
+		r := records[i].(*dnsRR_PTR)
+		name[i] = r.Ptr
+	}
+	return
+}