2011-06-12 18:22:31 -06:00
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// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package net
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import (
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"os"
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)
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// LookupHost looks up the given host using the local resolver.
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// It returns an array of that host's addresses.
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func LookupHost(host string) (addrs []string, err os.Error) {
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addrs, err, ok := cgoLookupHost(host)
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if !ok {
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addrs, err = goLookupHost(host)
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}
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return
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}
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// LookupIP looks up host using the local resolver.
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// It returns an array of that host's IPv4 and IPv6 addresses.
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func LookupIP(host string) (addrs []IP, err os.Error) {
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addrs, err, ok := cgoLookupIP(host)
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if !ok {
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addrs, err = goLookupIP(host)
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}
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return
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}
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// LookupPort looks up the port for the given network and service.
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func LookupPort(network, service string) (port int, err os.Error) {
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port, err, ok := cgoLookupPort(network, service)
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if !ok {
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port, err = goLookupPort(network, service)
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}
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return
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}
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// LookupCNAME returns the canonical DNS host for the given name.
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// Callers that do not care about the canonical name can call
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// LookupHost or LookupIP directly; both take care of resolving
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// the canonical name as part of the lookup.
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func LookupCNAME(name string) (cname string, err os.Error) {
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cname, err, ok := cgoLookupCNAME(name)
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if !ok {
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cname, err = goLookupCNAME(name)
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}
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return
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}
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// LookupSRV tries to resolve an SRV query of the given service,
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// protocol, and domain name, as specified in RFC 2782. In most cases
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// the proto argument can be the same as the corresponding
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// Addr.Network(). The returned records are sorted by priority
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// and randomized by weight within a priority.
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func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err os.Error) {
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target := "_" + service + "._" + proto + "." + name
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var records []dnsRR
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cname, records, err = lookup(target, dnsTypeSRV)
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if err != nil {
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return
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}
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addrs = make([]*SRV, len(records))
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for i, rr := range records {
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r := rr.(*dnsRR_SRV)
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addrs[i] = &SRV{r.Target, r.Port, r.Priority, r.Weight}
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}
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2011-08-04 18:27:51 -06:00
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byPriorityWeight(addrs).sort()
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2011-06-12 18:22:31 -06:00
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return
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}
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// LookupMX returns the DNS MX records for the given domain name sorted by preference.
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func LookupMX(name string) (mx []*MX, err os.Error) {
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2011-09-12 21:05:33 -06:00
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_, records, err := lookup(name, dnsTypeMX)
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2011-06-12 18:22:31 -06:00
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if err != nil {
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return
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}
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2011-09-12 21:05:33 -06:00
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mx = make([]*MX, len(records))
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for i, rr := range records {
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r := rr.(*dnsRR_MX)
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2011-06-12 18:22:31 -06:00
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mx[i] = &MX{r.Mx, r.Pref}
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}
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2011-08-04 18:27:51 -06:00
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byPref(mx).sort()
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2011-06-12 18:22:31 -06:00
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return
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}
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2011-09-12 21:05:33 -06:00
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// LookupTXT returns the DNS TXT records for the given domain name.
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func LookupTXT(name string) (txt []string, err os.Error) {
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_, records, err := lookup(name, dnsTypeTXT)
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if err != nil {
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return
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}
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txt = make([]string, len(records))
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for i, r := range records {
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txt[i] = r.(*dnsRR_TXT).Txt
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}
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return
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}
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2011-06-12 18:22:31 -06:00
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// LookupAddr performs a reverse lookup for the given address, returning a list
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// of names mapping to that address.
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func LookupAddr(addr string) (name []string, err os.Error) {
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name = lookupStaticAddr(addr)
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if len(name) > 0 {
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return
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}
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var arpa string
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arpa, err = reverseaddr(addr)
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if err != nil {
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return
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}
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var records []dnsRR
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_, records, err = lookup(arpa, dnsTypePTR)
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if err != nil {
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return
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}
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name = make([]string, len(records))
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for i := range records {
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r := records[i].(*dnsRR_PTR)
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name[i] = r.Ptr
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}
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return
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}
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