mirror of
https://github.com/autc04/Retro68.git
synced 2024-09-08 20:55:01 +00:00
160 lines
3.8 KiB
Go
160 lines
3.8 KiB
Go
// Copyright 2011 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.
|
|
|
|
// +build darwin dragonfly freebsd linux netbsd openbsd solaris
|
|
|
|
package net
|
|
|
|
import "sync"
|
|
|
|
var onceReadProtocols sync.Once
|
|
|
|
// readProtocols loads contents of /etc/protocols into protocols map
|
|
// for quick access.
|
|
func readProtocols() {
|
|
if file, err := open("/etc/protocols"); err == nil {
|
|
for line, ok := file.readLine(); ok; line, ok = file.readLine() {
|
|
// tcp 6 TCP # transmission control protocol
|
|
if i := byteIndex(line, '#'); i >= 0 {
|
|
line = line[0:i]
|
|
}
|
|
f := getFields(line)
|
|
if len(f) < 2 {
|
|
continue
|
|
}
|
|
if proto, _, ok := dtoi(f[1], 0); ok {
|
|
if _, ok := protocols[f[0]]; !ok {
|
|
protocols[f[0]] = proto
|
|
}
|
|
for _, alias := range f[2:] {
|
|
if _, ok := protocols[alias]; !ok {
|
|
protocols[alias] = proto
|
|
}
|
|
}
|
|
}
|
|
}
|
|
file.close()
|
|
}
|
|
}
|
|
|
|
// lookupProtocol looks up IP protocol name in /etc/protocols and
|
|
// returns correspondent protocol number.
|
|
func lookupProtocol(name string) (int, error) {
|
|
onceReadProtocols.Do(readProtocols)
|
|
proto, found := protocols[name]
|
|
if !found {
|
|
return 0, &AddrError{Err: "unknown IP protocol specified", Addr: name}
|
|
}
|
|
return proto, nil
|
|
}
|
|
|
|
func lookupHost(host string) (addrs []string, err error) {
|
|
order := systemConf().hostLookupOrder(host)
|
|
if order == hostLookupCgo {
|
|
if addrs, err, ok := cgoLookupHost(host); ok {
|
|
return addrs, err
|
|
}
|
|
// cgo not available (or netgo); fall back to Go's DNS resolver
|
|
order = hostLookupFilesDNS
|
|
}
|
|
return goLookupHostOrder(host, order)
|
|
}
|
|
|
|
func lookupIP(host string) (addrs []IPAddr, err error) {
|
|
order := systemConf().hostLookupOrder(host)
|
|
if order == hostLookupCgo {
|
|
if addrs, err, ok := cgoLookupIP(host); ok {
|
|
return addrs, err
|
|
}
|
|
// cgo not available (or netgo); fall back to Go's DNS resolver
|
|
order = hostLookupFilesDNS
|
|
}
|
|
return goLookupIPOrder(host, order)
|
|
}
|
|
|
|
func lookupPort(network, service string) (int, error) {
|
|
if systemConf().canUseCgo() {
|
|
if port, err, ok := cgoLookupPort(network, service); ok {
|
|
return port, err
|
|
}
|
|
}
|
|
return goLookupPort(network, service)
|
|
}
|
|
|
|
func lookupCNAME(name string) (string, error) {
|
|
if systemConf().canUseCgo() {
|
|
if cname, err, ok := cgoLookupCNAME(name); ok {
|
|
return cname, err
|
|
}
|
|
}
|
|
return goLookupCNAME(name)
|
|
}
|
|
|
|
func lookupSRV(service, proto, name string) (string, []*SRV, error) {
|
|
var target string
|
|
if service == "" && proto == "" {
|
|
target = name
|
|
} else {
|
|
target = "_" + service + "._" + proto + "." + name
|
|
}
|
|
cname, rrs, err := lookup(target, dnsTypeSRV)
|
|
if err != nil {
|
|
return "", nil, err
|
|
}
|
|
srvs := make([]*SRV, len(rrs))
|
|
for i, rr := range rrs {
|
|
rr := rr.(*dnsRR_SRV)
|
|
srvs[i] = &SRV{Target: rr.Target, Port: rr.Port, Priority: rr.Priority, Weight: rr.Weight}
|
|
}
|
|
byPriorityWeight(srvs).sort()
|
|
return cname, srvs, nil
|
|
}
|
|
|
|
func lookupMX(name string) ([]*MX, error) {
|
|
_, rrs, err := lookup(name, dnsTypeMX)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
mxs := make([]*MX, len(rrs))
|
|
for i, rr := range rrs {
|
|
rr := rr.(*dnsRR_MX)
|
|
mxs[i] = &MX{Host: rr.Mx, Pref: rr.Pref}
|
|
}
|
|
byPref(mxs).sort()
|
|
return mxs, nil
|
|
}
|
|
|
|
func lookupNS(name string) ([]*NS, error) {
|
|
_, rrs, err := lookup(name, dnsTypeNS)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
nss := make([]*NS, len(rrs))
|
|
for i, rr := range rrs {
|
|
nss[i] = &NS{Host: rr.(*dnsRR_NS).Ns}
|
|
}
|
|
return nss, nil
|
|
}
|
|
|
|
func lookupTXT(name string) ([]string, error) {
|
|
_, rrs, err := lookup(name, dnsTypeTXT)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
txts := make([]string, len(rrs))
|
|
for i, rr := range rrs {
|
|
txts[i] = rr.(*dnsRR_TXT).Txt
|
|
}
|
|
return txts, nil
|
|
}
|
|
|
|
func lookupAddr(addr string) ([]string, error) {
|
|
if systemConf().canUseCgo() {
|
|
if ptrs, err, ok := cgoLookupPTR(addr); ok {
|
|
return ptrs, err
|
|
}
|
|
}
|
|
return goLookupPTR(addr)
|
|
}
|