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authorTianon Gravi <admwiggin@gmail.com>2015-01-15 11:54:00 -0700
committerTianon Gravi <admwiggin@gmail.com>2015-01-15 11:54:00 -0700
commitf154da9e12608589e8d5f0508f908a0c3e88a1bb (patch)
treef8255d51e10c6f1e0ed69702200b966c9556a431 /src/pkg/net/dnsclient.go
parent8d8329ed5dfb9622c82a9fbec6fd99a580f9c9f6 (diff)
downloadgolang-f154da9e12608589e8d5f0508f908a0c3e88a1bb.tar.gz
Imported Upstream version 1.4upstream/1.4
Diffstat (limited to 'src/pkg/net/dnsclient.go')
-rw-r--r--src/pkg/net/dnsclient.go251
1 files changed, 0 insertions, 251 deletions
diff --git a/src/pkg/net/dnsclient.go b/src/pkg/net/dnsclient.go
deleted file mode 100644
index 9bffa11f9..000000000
--- a/src/pkg/net/dnsclient.go
+++ /dev/null
@@ -1,251 +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.
-
-package net
-
-import (
- "math/rand"
- "sort"
-)
-
-// DNSError represents a DNS lookup error.
-type DNSError struct {
- Err string // description of the error
- Name string // name looked for
- Server string // server used
- IsTimeout bool
-}
-
-func (e *DNSError) Error() string {
- if e == nil {
- return "<nil>"
- }
- s := "lookup " + e.Name
- if e.Server != "" {
- s += " on " + e.Server
- }
- s += ": " + e.Err
- return s
-}
-
-func (e *DNSError) Timeout() bool { return e.IsTimeout }
-func (e *DNSError) Temporary() bool { return e.IsTimeout }
-
-const noSuchHost = "no such host"
-
-// reverseaddr returns the in-addr.arpa. or ip6.arpa. hostname of the IP
-// address addr suitable for rDNS (PTR) record lookup or an error if it fails
-// to parse the IP address.
-func reverseaddr(addr string) (arpa string, err error) {
- ip := ParseIP(addr)
- if ip == nil {
- return "", &DNSError{Err: "unrecognized address", Name: addr}
- }
- if ip.To4() != nil {
- return itoa(int(ip[15])) + "." + itoa(int(ip[14])) + "." + itoa(int(ip[13])) + "." +
- itoa(int(ip[12])) + ".in-addr.arpa.", nil
- }
- // Must be IPv6
- buf := make([]byte, 0, len(ip)*4+len("ip6.arpa."))
- // Add it, in reverse, to the buffer
- for i := len(ip) - 1; i >= 0; i-- {
- v := ip[i]
- buf = append(buf, hexDigit[v&0xF])
- buf = append(buf, '.')
- buf = append(buf, hexDigit[v>>4])
- buf = append(buf, '.')
- }
- // Append "ip6.arpa." and return (buf already has the final .)
- buf = append(buf, "ip6.arpa."...)
- return string(buf), nil
-}
-
-// Find answer for name in dns message.
-// On return, if err == nil, addrs != nil.
-func answer(name, server string, dns *dnsMsg, qtype uint16) (cname string, addrs []dnsRR, err error) {
- addrs = make([]dnsRR, 0, len(dns.answer))
-
- if dns.rcode == dnsRcodeNameError && dns.recursion_available {
- return "", nil, &DNSError{Err: noSuchHost, Name: name}
- }
- if dns.rcode != dnsRcodeSuccess {
- // None of the error codes make sense
- // for the query we sent. If we didn't get
- // a name error and we didn't get success,
- // the server is behaving incorrectly.
- return "", nil, &DNSError{Err: "server misbehaving", Name: name, Server: server}
- }
-
- // Look for the name.
- // Presotto says it's okay to assume that servers listed in
- // /etc/resolv.conf are recursive resolvers.
- // We asked for recursion, so it should have included
- // all the answers we need in this one packet.
-Cname:
- for cnameloop := 0; cnameloop < 10; cnameloop++ {
- addrs = addrs[0:0]
- for _, rr := range dns.answer {
- if _, justHeader := rr.(*dnsRR_Header); justHeader {
- // Corrupt record: we only have a
- // header. That header might say it's
- // of type qtype, but we don't
- // actually have it. Skip.
- continue
- }
- h := rr.Header()
- if h.Class == dnsClassINET && h.Name == name {
- switch h.Rrtype {
- case qtype:
- addrs = append(addrs, rr)
- case dnsTypeCNAME:
- // redirect to cname
- name = rr.(*dnsRR_CNAME).Cname
- continue Cname
- }
- }
- }
- if len(addrs) == 0 {
- return "", nil, &DNSError{Err: noSuchHost, Name: name, Server: server}
- }
- return name, addrs, nil
- }
-
- return "", nil, &DNSError{Err: "too many redirects", Name: name, Server: server}
-}
-
-func isDomainName(s string) bool {
- // See RFC 1035, RFC 3696.
- if len(s) == 0 {
- return false
- }
- if len(s) > 255 {
- return false
- }
-
- last := byte('.')
- ok := false // Ok once we've seen a letter.
- partlen := 0
- for i := 0; i < len(s); i++ {
- c := s[i]
- switch {
- default:
- return false
- case 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || c == '_':
- ok = true
- partlen++
- case '0' <= c && c <= '9':
- // fine
- partlen++
- case c == '-':
- // Byte before dash cannot be dot.
- if last == '.' {
- return false
- }
- partlen++
- case c == '.':
- // Byte before dot cannot be dot, dash.
- if last == '.' || last == '-' {
- return false
- }
- if partlen > 63 || partlen == 0 {
- return false
- }
- partlen = 0
- }
- last = c
- }
- if last == '-' || partlen > 63 {
- return false
- }
-
- return ok
-}
-
-// An SRV represents a single DNS SRV record.
-type SRV struct {
- Target string
- Port uint16
- Priority uint16
- Weight uint16
-}
-
-// byPriorityWeight sorts SRV records by ascending priority and weight.
-type byPriorityWeight []*SRV
-
-func (s byPriorityWeight) Len() int { return len(s) }
-
-func (s byPriorityWeight) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
-
-func (s byPriorityWeight) Less(i, j int) bool {
- return s[i].Priority < s[j].Priority ||
- (s[i].Priority == s[j].Priority && s[i].Weight < s[j].Weight)
-}
-
-// shuffleByWeight shuffles SRV records by weight using the algorithm
-// described in RFC 2782.
-func (addrs byPriorityWeight) shuffleByWeight() {
- sum := 0
- for _, addr := range addrs {
- sum += int(addr.Weight)
- }
- for sum > 0 && len(addrs) > 1 {
- s := 0
- n := rand.Intn(sum)
- for i := range addrs {
- s += int(addrs[i].Weight)
- if s > n {
- if i > 0 {
- t := addrs[i]
- copy(addrs[1:i+1], addrs[0:i])
- addrs[0] = t
- }
- break
- }
- }
- sum -= int(addrs[0].Weight)
- addrs = addrs[1:]
- }
-}
-
-// 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
- Pref uint16
-}
-
-// byPref implements sort.Interface to sort MX records by preference
-type byPref []*MX
-
-func (s byPref) Len() int { return len(s) }
-
-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)
-}
-
-// An NS represents a single DNS NS record.
-type NS struct {
- Host string
-}