defer releaseThread()
var r *syscall.DNSRecord
e := syscall.DnsQuery(name, syscall.DNS_TYPE_CNAME, 0, nil, &r, nil)
+ // windows returns DNS_INFO_NO_RECORDS if there are no CNAME-s
+ if errno, ok := e.(syscall.Errno); ok && errno == syscall.DNS_INFO_NO_RECORDS {
+ // if there are no aliases, the canonical name is the input name
+ if name == "" || name[len(name)-1] != '.' {
+ return name + ".", nil
+ }
+ return name, nil
+ }
if e != nil {
return "", os.NewSyscallError("LookupCNAME", e)
}
defer syscall.DnsRecordListFree(r, 1)
- if r != nil && r.Type == syscall.DNS_TYPE_CNAME {
- v := (*syscall.DNSPTRData)(unsafe.Pointer(&r.Data[0]))
- cname = syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]) + "."
- }
+
+ resolved := resolveCNAME(syscall.StringToUTF16Ptr(name), r)
+ cname = syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(resolved))[:]) + "."
return
}
return "", nil, os.NewSyscallError("LookupSRV", e)
}
defer syscall.DnsRecordListFree(r, 1)
+
addrs = make([]*SRV, 0, 10)
- for p := r; p != nil && p.Type == syscall.DNS_TYPE_SRV; p = p.Next {
+ for _, p := range validRecs(r, syscall.DNS_TYPE_SRV, target) {
v := (*syscall.DNSSRVData)(unsafe.Pointer(&p.Data[0]))
addrs = append(addrs, &SRV{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Target))[:]), v.Port, v.Priority, v.Weight})
}
return nil, os.NewSyscallError("LookupMX", 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 {
+ for _, p := range validRecs(r, syscall.DNS_TYPE_MX, name) {
v := (*syscall.DNSMXData)(unsafe.Pointer(&p.Data[0]))
mx = append(mx, &MX{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.NameExchange))[:]) + ".", v.Preference})
}
return nil, os.NewSyscallError("LookupNS", e)
}
defer syscall.DnsRecordListFree(r, 1)
+
ns = make([]*NS, 0, 10)
- for p := r; p != nil && p.Type == syscall.DNS_TYPE_NS; p = p.Next {
+ for _, p := range validRecs(r, syscall.DNS_TYPE_NS, name) {
v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0]))
ns = append(ns, &NS{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]) + "."})
}
return nil, os.NewSyscallError("LookupTXT", e)
}
defer syscall.DnsRecordListFree(r, 1)
+
txt = make([]string, 0, 10)
- if r != nil && r.Type == syscall.DNS_TYPE_TEXT {
- d := (*syscall.DNSTXTData)(unsafe.Pointer(&r.Data[0]))
+ for _, p := range validRecs(r, syscall.DNS_TYPE_TEXT, name) {
+ d := (*syscall.DNSTXTData)(unsafe.Pointer(&p.Data[0]))
for _, v := range (*[1 << 10]*uint16)(unsafe.Pointer(&(d.StringArray[0])))[:d.StringCount] {
s := syscall.UTF16ToString((*[1 << 20]uint16)(unsafe.Pointer(v))[:])
txt = append(txt, s)
return nil, os.NewSyscallError("LookupAddr", 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 {
+ for _, p := range validRecs(r, syscall.DNS_TYPE_PTR, arpa) {
v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0]))
name = append(name, syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]))
}
return name, nil
}
+
+const dnsSectionMask = 0x0003
+
+// returns only results applicable to name and resolves CNAME entries
+func validRecs(r *syscall.DNSRecord, dnstype uint16, name string) []*syscall.DNSRecord {
+ cname := syscall.StringToUTF16Ptr(name)
+ if dnstype != syscall.DNS_TYPE_CNAME {
+ cname = resolveCNAME(cname, r)
+ }
+ rec := make([]*syscall.DNSRecord, 0, 10)
+ for p := r; p != nil; p = p.Next {
+ if p.Dw&dnsSectionMask != syscall.DnsSectionAnswer {
+ continue
+ }
+ if p.Type != dnstype {
+ continue
+ }
+ if !syscall.DnsNameCompare(cname, p.Name) {
+ continue
+ }
+ rec = append(rec, p)
+ }
+ return rec
+}
+
+// returns the last CNAME in chain
+func resolveCNAME(name *uint16, r *syscall.DNSRecord) *uint16 {
+ // limit cname resolving to 10 in case of a infinite CNAME loop
+Cname:
+ for cnameloop := 0; cnameloop < 10; cnameloop++ {
+ for p := r; p != nil; p = p.Next {
+ if p.Dw&dnsSectionMask != syscall.DnsSectionAnswer {
+ continue
+ }
+ if p.Type != syscall.DNS_TYPE_CNAME {
+ continue
+ }
+ if !syscall.DnsNameCompare(name, p.Name) {
+ continue
+ }
+ name = (*syscall.DNSPTRData)(unsafe.Pointer(&r.Data[0])).Host
+ continue Cname
+ }
+ break
+ }
+ return name
+}
--- /dev/null
+// 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.
+
+package net
+
+import (
+ "bytes"
+ "encoding/json"
+ "errors"
+ "os/exec"
+ "reflect"
+ "regexp"
+ "sort"
+ "strconv"
+ "strings"
+ "testing"
+)
+
+var nslookupTestServers = []string{"mail.golang.com", "gmail.com"}
+
+func toJson(v interface{}) string {
+ data, _ := json.Marshal(v)
+ return string(data)
+}
+
+func TestLookupMX(t *testing.T) {
+ if testing.Short() || !*testExternal {
+ t.Skip("skipping test to avoid external network")
+ }
+ for _, server := range nslookupTestServers {
+ mx, err := LookupMX(server)
+ if err != nil {
+ t.Errorf("failed %s: %s", server, err)
+ continue
+ }
+ if len(mx) == 0 {
+ t.Errorf("no results")
+ continue
+ }
+ expected, err := nslookupMX(server)
+ if err != nil {
+ t.Logf("skipping failed nslookup %s test: %s", server, err)
+ }
+ sort.Sort(byPrefAndHost(expected))
+ sort.Sort(byPrefAndHost(mx))
+ if !reflect.DeepEqual(expected, mx) {
+ t.Errorf("different results %s:\texp:%v\tgot:%v", server, toJson(expected), toJson(mx))
+ }
+ }
+}
+
+func TestLookupCNAME(t *testing.T) {
+ if testing.Short() || !*testExternal {
+ t.Skip("skipping test to avoid external network")
+ }
+ for _, server := range nslookupTestServers {
+ cname, err := LookupCNAME(server)
+ if err != nil {
+ t.Errorf("failed %s: %s", server, err)
+ continue
+ }
+ if cname == "" {
+ t.Errorf("no result %s", server)
+ }
+ expected, err := nslookupCNAME(server)
+ if err != nil {
+ t.Logf("skipping failed nslookup %s test: %s", server, err)
+ continue
+ }
+ if expected != cname {
+ t.Errorf("different results %s:\texp:%v\tgot:%v", server, expected, cname)
+ }
+ }
+}
+
+func TestLookupNS(t *testing.T) {
+ if testing.Short() || !*testExternal {
+ t.Skip("skipping test to avoid external network")
+ }
+ for _, server := range nslookupTestServers {
+ ns, err := LookupNS(server)
+ if err != nil {
+ t.Errorf("failed %s: %s", server, err)
+ continue
+ }
+ if len(ns) == 0 {
+ t.Errorf("no results")
+ continue
+ }
+ expected, err := nslookupNS(server)
+ if err != nil {
+ t.Logf("skipping failed nslookup %s test: %s", server, err)
+ continue
+ }
+ sort.Sort(byHost(expected))
+ sort.Sort(byHost(ns))
+ if !reflect.DeepEqual(expected, ns) {
+ t.Errorf("different results %s:\texp:%v\tgot:%v", toJson(server), toJson(expected), ns)
+ }
+ }
+}
+
+func TestLookupTXT(t *testing.T) {
+ if testing.Short() || !*testExternal {
+ t.Skip("skipping test to avoid external network")
+ }
+ for _, server := range nslookupTestServers {
+ txt, err := LookupTXT(server)
+ if err != nil {
+ t.Errorf("failed %s: %s", server, err)
+ continue
+ }
+ if len(txt) == 0 {
+ t.Errorf("no results")
+ continue
+ }
+ expected, err := nslookupTXT(server)
+ if err != nil {
+ t.Logf("skipping failed nslookup %s test: %s", server, err)
+ continue
+ }
+ sort.Strings(expected)
+ sort.Strings(txt)
+ if !reflect.DeepEqual(expected, txt) {
+ t.Errorf("different results %s:\texp:%v\tgot:%v", server, toJson(expected), toJson(txt))
+ }
+ }
+}
+
+type byPrefAndHost []*MX
+
+func (s byPrefAndHost) Len() int { return len(s) }
+func (s byPrefAndHost) Less(i, j int) bool {
+ if s[i].Pref != s[j].Pref {
+ return s[i].Pref < s[j].Pref
+ }
+ return s[i].Host < s[j].Host
+}
+func (s byPrefAndHost) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+
+type byHost []*NS
+
+func (s byHost) Len() int { return len(s) }
+func (s byHost) Less(i, j int) bool { return s[i].Host < s[j].Host }
+func (s byHost) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+
+func fqdn(s string) string {
+ if len(s) == 0 || s[len(s)-1] != '.' {
+ return s + "."
+ }
+ return s
+}
+
+func nslookup(qtype, name string) (string, error) {
+ var out bytes.Buffer
+ var err bytes.Buffer
+ cmd := exec.Command("nslookup", "-querytype="+qtype, name)
+ cmd.Stdout = &out
+ cmd.Stderr = &err
+ if err := cmd.Run(); err != nil {
+ return "", err
+ }
+ r := strings.Replace(out.String(), "\r\n", "\n", -1)
+ // nslookup stderr output contains also debug information such as
+ // "Non-authoritative answer" and it doesn't return the correct errcode
+ if strings.Contains(err.String(), "can't find") {
+ return r, errors.New(err.String())
+ }
+ return r, nil
+}
+
+func nslookupMX(name string) (mx []*MX, err error) {
+ var r string
+ if r, err = nslookup("mx", name); err != nil {
+ return
+ }
+ mx = make([]*MX, 0, 10)
+ // linux nslookup syntax
+ // golang.org mail exchanger = 2 alt1.aspmx.l.google.com.
+ rx := regexp.MustCompile(`(?m)^([a-z0-9.\-]+)\s+mail exchanger\s*=\s*([0-9]+)\s*([a-z0-9.\-]+)$`)
+ for _, ans := range rx.FindAllStringSubmatch(r, -1) {
+ pref, _ := strconv.Atoi(ans[2])
+ mx = append(mx, &MX{fqdn(ans[3]), uint16(pref)})
+ }
+ // windows nslookup syntax
+ // gmail.com MX preference = 30, mail exchanger = alt3.gmail-smtp-in.l.google.com
+ rx = regexp.MustCompile(`(?m)^([a-z0-9.\-]+)\s+MX preference\s*=\s*([0-9]+)\s*,\s*mail exchanger\s*=\s*([a-z0-9.\-]+)$`)
+ for _, ans := range rx.FindAllStringSubmatch(r, -1) {
+ pref, _ := strconv.Atoi(ans[2])
+ mx = append(mx, &MX{fqdn(ans[3]), uint16(pref)})
+ }
+ return
+}
+
+func nslookupNS(name string) (ns []*NS, err error) {
+ var r string
+ if r, err = nslookup("ns", name); err != nil {
+ return
+ }
+ ns = make([]*NS, 0, 10)
+ // golang.org nameserver = ns1.google.com.
+ rx := regexp.MustCompile(`(?m)^([a-z0-9.\-]+)\s+nameserver\s*=\s*([a-z0-9.\-]+)$`)
+ for _, ans := range rx.FindAllStringSubmatch(r, -1) {
+ ns = append(ns, &NS{fqdn(ans[2])})
+ }
+ return
+}
+
+func nslookupCNAME(name string) (cname string, err error) {
+ var r string
+ if r, err = nslookup("cname", name); err != nil {
+ return
+ }
+ // mail.golang.com canonical name = golang.org.
+ rx := regexp.MustCompile(`(?m)^([a-z0-9.\-]+)\s+canonical name\s*=\s*([a-z0-9.\-]+)$`)
+ // assumes the last CNAME is the correct one
+ last := name
+ for _, ans := range rx.FindAllStringSubmatch(r, -1) {
+ last = ans[2]
+ }
+ return fqdn(last), nil
+}
+
+func nslookupTXT(name string) (txt []string, err error) {
+ var r string
+ if r, err = nslookup("txt", name); err != nil {
+ return
+ }
+ txt = make([]string, 0, 10)
+ // linux
+ // golang.org text = "v=spf1 redirect=_spf.google.com"
+
+ // windows
+ // golang.org text =
+ //
+ // "v=spf1 redirect=_spf.google.com"
+ rx := regexp.MustCompile(`(?m)^([a-z0-9.\-]+)\s+text\s*=\s*"(.*)"$`)
+ for _, ans := range rx.FindAllStringSubmatch(r, -1) {
+ txt = append(txt, ans[2])
+ }
+ return
+}
//sys GetProtoByName(name string) (p *Protoent, err error) [failretval==nil] = ws2_32.getprotobyname
//sys DnsQuery(name string, qtype uint16, options uint32, extra *byte, qrs **DNSRecord, pr *byte) (status error) = dnsapi.DnsQuery_W
//sys DnsRecordListFree(rl *DNSRecord, freetype uint32) = dnsapi.DnsRecordListFree
+//sys DnsNameCompare(name1 *uint16, name2 *uint16) (same bool) = dnsapi.DnsNameCompare_W
//sys GetAddrInfoW(nodename *uint16, servicename *uint16, hints *AddrinfoW, result **AddrinfoW) (sockerr error) = ws2_32.GetAddrInfoW
//sys FreeAddrInfoW(addrinfo *AddrinfoW) = ws2_32.FreeAddrInfoW
//sys GetIfEntry(pIfRow *MibIfRow) (errcode error) = iphlpapi.GetIfEntry
-// go build mksyscall_windows.go && ./mksyscall_windows syscall_windows.go security_windows.go syscall_windows_386.go
+// go build mksyscall_windows.go && ./mksyscall_windows syscall_windows.go security_windows.go
// MACHINE GENERATED BY THE COMMAND ABOVE; DO NOT EDIT
package syscall
procgetprotobyname = modws2_32.NewProc("getprotobyname")
procDnsQuery_W = moddnsapi.NewProc("DnsQuery_W")
procDnsRecordListFree = moddnsapi.NewProc("DnsRecordListFree")
+ procDnsNameCompare_W = moddnsapi.NewProc("DnsNameCompare_W")
procGetAddrInfoW = modws2_32.NewProc("GetAddrInfoW")
procFreeAddrInfoW = modws2_32.NewProc("FreeAddrInfoW")
procGetIfEntry = modiphlpapi.NewProc("GetIfEntry")
return
}
+func DnsNameCompare(name1 *uint16, name2 *uint16) (same bool) {
+ r0, _, _ := Syscall(procDnsNameCompare_W.Addr(), 2, uintptr(unsafe.Pointer(name1)), uintptr(unsafe.Pointer(name2)), 0)
+ same = r0 != 0
+ return
+}
+
func GetAddrInfoW(nodename *uint16, servicename *uint16, hints *AddrinfoW, result **AddrinfoW) (sockerr error) {
r0, _, _ := Syscall6(procGetAddrInfoW.Addr(), 4, uintptr(unsafe.Pointer(nodename)), uintptr(unsafe.Pointer(servicename)), uintptr(unsafe.Pointer(hints)), uintptr(unsafe.Pointer(result)), 0, 0)
if r0 != 0 {
-// go build mksyscall_windows.go && ./mksyscall_windows syscall_windows.go security_windows.go syscall_windows_amd64.go
+// go build mksyscall_windows.go && ./mksyscall_windows syscall_windows.go security_windows.go
// MACHINE GENERATED BY THE COMMAND ABOVE; DO NOT EDIT
package syscall
procgetprotobyname = modws2_32.NewProc("getprotobyname")
procDnsQuery_W = moddnsapi.NewProc("DnsQuery_W")
procDnsRecordListFree = moddnsapi.NewProc("DnsRecordListFree")
+ procDnsNameCompare_W = moddnsapi.NewProc("DnsNameCompare_W")
procGetAddrInfoW = modws2_32.NewProc("GetAddrInfoW")
procFreeAddrInfoW = modws2_32.NewProc("FreeAddrInfoW")
procGetIfEntry = modiphlpapi.NewProc("GetIfEntry")
return
}
+func DnsNameCompare(name1 *uint16, name2 *uint16) (same bool) {
+ r0, _, _ := Syscall(procDnsNameCompare_W.Addr(), 2, uintptr(unsafe.Pointer(name1)), uintptr(unsafe.Pointer(name2)), 0)
+ same = r0 != 0
+ return
+}
+
func GetAddrInfoW(nodename *uint16, servicename *uint16, hints *AddrinfoW, result **AddrinfoW) (sockerr error) {
r0, _, _ := Syscall6(procGetAddrInfoW.Addr(), 4, uintptr(unsafe.Pointer(nodename)), uintptr(unsafe.Pointer(servicename)), uintptr(unsafe.Pointer(hints)), uintptr(unsafe.Pointer(result)), 0, 0)
if r0 != 0 {
DNS_TYPE_NBSTAT = 0xff01
)
+const (
+ DNS_INFO_NO_RECORDS = 0x251D
+)
+
+const (
+ // flags inside DNSRecord.Dw
+ DnsSectionQuestion = 0x0000
+ DnsSectionAnswer = 0x0001
+ DnsSectionAuthority = 0x0002
+ DnsSectionAdditional = 0x0003
+)
+
type DNSSRVData struct {
Target *uint16
Priority uint16