net: add LookupMX

R=rsc
CC=golang-dev
https://golang.org/cl/1976049

diff --git a/src/pkg/net/dnsclient.go b/src/pkg/net/dnsclient.go
index 619d9e2e0312a6bb5c3531501dfa1cb37063849b..18bd72c3f16c5e98885689ed07863bb705aa9b4b 100644 (file)
--- a/src/pkg/net/dnsclient.go
+++ b/src/pkg/net/dnsclient.go
@@ -335,3 +335,22 @@ func LookupSRV(name string) (cname string, addrs []*SRV, err os.Error) {
        }
        return
 }
+
+type MX struct {
+       Host string
+       Pref uint16
+}
+
+func LookupMX(name string) (entries []*MX, err os.Error) {
+       var records []dnsRR
+       _, records, err = lookup(name, dnsTypeMX)
+       if err != nil {
+               return
+       }
+       entries = make([]*MX, len(records))
+       for i := 0; i < len(records); i++ {
+               r := records[i].(*dnsRR_MX)
+               entries[i] = &MX{r.Mx, r.Pref}
+       }
+       return
+}