net: implement windows LookupMX and LookupAddr
Also sort SRV records before returning from LookupSRV.
R=rsc
CC=golang-dev
https://golang.org/cl/4817049
diff --git a/src/pkg/net/dnsclient.go b/src/pkg/net/dnsclient.go
index 280b194..93c04f6 100644
--- a/src/pkg/net/dnsclient.go
+++ b/src/pkg/net/dnsclient.go
@@ -9,6 +9,7 @@
"fmt"
"os"
"rand"
+ "sort"
)
// DNSError represents a DNS lookup error.
@@ -182,9 +183,9 @@
(s[i].Priority == s[j].Priority && s[i].Weight < s[j].Weight)
}
-// shuffleSRVByWeight shuffles SRV records by weight using the algorithm
+// shuffleByWeight shuffles SRV records by weight using the algorithm
// described in RFC 2782.
-func shuffleSRVByWeight(addrs []*SRV) {
+func (addrs byPriorityWeight) shuffleByWeight() {
sum := 0
for _, addr := range addrs {
sum += int(addr.Weight)
@@ -208,6 +209,19 @@
}
}
+// sort reorders SRV records as specified in RFC 2782.
+func (addrs byPriorityWeight) sort() {
+ sort.Sort(addrs)
+ i := 0
+ for j := 1; j < len(addrs); j++ {
+ if addrs[i].Priority != addrs[j].Priority {
+ addrs[i:j].shuffleByWeight()
+ i = j
+ }
+ }
+ addrs[i:].shuffleByWeight()
+}
+
// An MX represents a single DNS MX record.
type MX struct {
Host string
@@ -222,3 +236,12 @@
func (s byPref) Less(i, j int) bool { return s[i].Pref < s[j].Pref }
func (s byPref) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+
+// sort reorders MX records as specified in RFC 5321.
+func (s byPref) sort() {
+ for i := range s {
+ j := rand.Intn(i + 1)
+ s[i], s[j] = s[j], s[i]
+ }
+ sort.Sort(s)
+}
diff --git a/src/pkg/net/lookup_test.go b/src/pkg/net/lookup_test.go
new file mode 100644
index 0000000..995ab03
--- /dev/null
+++ b/src/pkg/net/lookup_test.go
@@ -0,0 +1,57 @@
+// 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.
+
+// TODO It would be nice to use a mock DNS server, to eliminate
+// external dependencies.
+
+package net
+
+import (
+ "runtime"
+ "testing"
+)
+
+var avoidMacFirewall = runtime.GOOS == "darwin"
+
+func TestGoogleSRV(t *testing.T) {
+ if testing.Short() || avoidMacFirewall {
+ t.Logf("skipping test to avoid external network")
+ return
+ }
+ _, addrs, err := LookupSRV("xmpp-server", "tcp", "google.com")
+ if err != nil {
+ t.Errorf("failed: %s", err)
+ }
+ if len(addrs) == 0 {
+ t.Errorf("no results")
+ }
+}
+
+func TestGmailMX(t *testing.T) {
+ if testing.Short() || avoidMacFirewall {
+ t.Logf("skipping test to avoid external network")
+ return
+ }
+ mx, err := LookupMX("gmail.com")
+ if err != nil {
+ t.Errorf("failed: %s", err)
+ }
+ if len(mx) == 0 {
+ t.Errorf("no results")
+ }
+}
+
+func TestGoogleDNSAddr(t *testing.T) {
+ if testing.Short() || avoidMacFirewall {
+ t.Logf("skipping test to avoid external network")
+ return
+ }
+ names, err := LookupAddr("8.8.8.8")
+ if err != nil {
+ t.Errorf("failed: %s", err)
+ }
+ if len(names) == 0 {
+ t.Errorf("no results")
+ }
+}
diff --git a/src/pkg/net/lookup_unix.go b/src/pkg/net/lookup_unix.go
index 168d3fa..8f5e662 100644
--- a/src/pkg/net/lookup_unix.go
+++ b/src/pkg/net/lookup_unix.go
@@ -6,8 +6,6 @@
import (
"os"
- "rand"
- "sort"
)
// LookupHost looks up the given host using the local resolver.
@@ -68,15 +66,7 @@
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)])
+ byPriorityWeight(addrs).sort()
return
}
@@ -91,12 +81,7 @@
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))
+ byPref(mx).sort()
return
}
diff --git a/src/pkg/net/lookup_windows.go b/src/pkg/net/lookup_windows.go
index 16b37f5..fa3ad7c 100644
--- a/src/pkg/net/lookup_windows.go
+++ b/src/pkg/net/lookup_windows.go
@@ -85,23 +85,46 @@
return "", nil, os.NewSyscallError("LookupSRV", int(e))
}
defer syscall.DnsRecordListFree(r, 1)
- addrs = make([]*SRV, 100)
- i := 0
+ addrs = make([]*SRV, 0, 10)
for p := r; p != nil && p.Type == syscall.DNS_TYPE_SRV; p = p.Next {
v := (*syscall.DNSSRVData)(unsafe.Pointer(&p.Data[0]))
- addrs[i] = &SRV{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Target))[:]), v.Port, v.Priority, v.Weight}
- i++
+ addrs = append(addrs, &SRV{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Target))[:]), v.Port, v.Priority, v.Weight})
}
- addrs = addrs[0:i]
+ byPriorityWeight(addrs).sort()
return name, addrs, nil
}
-// TODO(brainman): implement LookupMX and LookupAddr.
-
func LookupMX(name string) (mx []*MX, err os.Error) {
- return nil, os.NewSyscallError("LookupMX", syscall.EWINDOWS)
+ var r *syscall.DNSRecord
+ e := syscall.DnsQuery(name, syscall.DNS_TYPE_MX, 0, nil, &r, nil)
+ if int(e) != 0 {
+ return nil, os.NewSyscallError("LookupMX", int(e))
+ }
+ defer syscall.DnsRecordListFree(r, 1)
+ mx = make([]*MX, 0, 10)
+ for p := r; p != nil && p.Type == syscall.DNS_TYPE_MX; p = p.Next {
+ v := (*syscall.DNSMXData)(unsafe.Pointer(&p.Data[0]))
+ mx = append(mx, &MX{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.NameExchange))[:]) + ".", v.Preference})
+ }
+ byPref(mx).sort()
+ return mx, nil
}
func LookupAddr(addr string) (name []string, err os.Error) {
- return nil, os.NewSyscallError("LookupAddr", syscall.EWINDOWS)
+ arpa, err := reverseaddr(addr)
+ if err != nil {
+ return nil, err
+ }
+ var r *syscall.DNSRecord
+ e := syscall.DnsQuery(arpa, syscall.DNS_TYPE_PTR, 0, nil, &r, nil)
+ if int(e) != 0 {
+ return nil, os.NewSyscallError("LookupAddr", int(e))
+ }
+ defer syscall.DnsRecordListFree(r, 1)
+ name = make([]string, 0, 10)
+ for p := r; p != nil && p.Type == syscall.DNS_TYPE_PTR; p = p.Next {
+ v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0]))
+ name = append(name, syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]))
+ }
+ return name, nil
}
diff --git a/src/pkg/net/srv_test.go b/src/pkg/net/srv_test.go
deleted file mode 100644
index f1c7a0a..0000000
--- a/src/pkg/net/srv_test.go
+++ /dev/null
@@ -1,29 +0,0 @@
-// 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.
-
-// TODO It would be nice to use a mock DNS server, to eliminate
-// external dependencies.
-
-package net
-
-import (
- "runtime"
- "testing"
-)
-
-var avoidMacFirewall = runtime.GOOS == "darwin"
-
-func TestGoogleSRV(t *testing.T) {
- if testing.Short() || avoidMacFirewall {
- t.Logf("skipping test to avoid external network")
- return
- }
- _, addrs, err := LookupSRV("xmpp-server", "tcp", "google.com")
- if err != nil {
- t.Errorf("failed: %s", err)
- }
- if len(addrs) == 0 {
- t.Errorf("no results")
- }
-}
diff --git a/src/pkg/syscall/ztypes_windows.go b/src/pkg/syscall/ztypes_windows.go
index 10780f7..07f2b85 100644
--- a/src/pkg/syscall/ztypes_windows.go
+++ b/src/pkg/syscall/ztypes_windows.go
@@ -478,6 +478,12 @@
Host *uint16
}
+type DNSMXData struct {
+ NameExchange *uint16
+ Preference uint16
+ Pad uint16
+}
+
type DNSRecord struct {
Next *DNSRecord
Name *uint16
