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// 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 freebsd linux
package net
/*
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
*/
import (
"syscall"
"unsafe"
)
//extern getaddrinfo
func libc_getaddrinfo(node *byte, service *byte, hints *syscall.Addrinfo, res **syscall.Addrinfo) int
//extern freeaddrinfo
func libc_freeaddrinfo(res *syscall.Addrinfo)
//extern gai_strerror
func libc_gai_strerror(errcode int) *byte
// bytePtrToString takes a NUL-terminated array of bytes and convert
// it to a Go string.
func bytePtrToString(p *byte) string {
a := (*[10000]byte)(unsafe.Pointer(p))
i := 0
for a[i] != 0 {
i++
}
return string(a[:i])
}
func cgoLookupHost(name string) (addrs []string, err error, completed bool) {
ip, err, completed := cgoLookupIP(name)
for _, p := range ip {
addrs = append(addrs, p.String())
}
return
}
func cgoLookupPort(net, service string) (port int, err error, completed bool) {
var res *syscall.Addrinfo
var hints syscall.Addrinfo
switch net {
case "":
// no hints
case "tcp", "tcp4", "tcp6":
hints.Ai_socktype = syscall.SOCK_STREAM
hints.Ai_protocol = syscall.IPPROTO_TCP
case "udp", "udp4", "udp6":
hints.Ai_socktype = syscall.SOCK_DGRAM
hints.Ai_protocol = syscall.IPPROTO_UDP
default:
return 0, UnknownNetworkError(net), true
}
if len(net) >= 4 {
switch net[3] {
case '4':
hints.Ai_family = syscall.AF_INET
case '6':
hints.Ai_family = syscall.AF_INET6
}
}
s := syscall.StringBytePtr(service)
syscall.Entersyscall()
gerrno := libc_getaddrinfo(nil, s, &hints, &res)
syscall.Exitsyscall()
if gerrno == 0 {
defer libc_freeaddrinfo(res)
for r := res; r != nil; r = r.Ai_next {
switch r.Ai_family {
default:
continue
case syscall.AF_INET:
sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(r.Ai_addr))
p := (*[2]byte)(unsafe.Pointer(&sa.Port))
return int(p[0])<<8 | int(p[1]), nil, true
case syscall.AF_INET6:
sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(r.Ai_addr))
p := (*[2]byte)(unsafe.Pointer(&sa.Port))
return int(p[0])<<8 | int(p[1]), nil, true
}
}
}
return 0, &AddrError{"unknown port", net + "/" + service}, true
}
func cgoLookupIPCNAME(name string) (addrs []IP, cname string, err error, completed bool) {
var res *syscall.Addrinfo
var hints syscall.Addrinfo
// NOTE(rsc): In theory there are approximately balanced
// arguments for and against including AI_ADDRCONFIG
// in the flags (it includes IPv4 results only on IPv4 systems,
// and similarly for IPv6), but in practice setting it causes
// getaddrinfo to return the wrong canonical name on Linux.
// So definitely leave it out.
hints.Ai_flags = int32((syscall.AI_ALL | syscall.AI_V4MAPPED | syscall.AI_CANONNAME) & cgoAddrInfoMask())
h := syscall.StringBytePtr(name)
syscall.Entersyscall()
gerrno := libc_getaddrinfo(h, nil, &hints, &res)
syscall.Exitsyscall()
if gerrno != 0 {
var str string
if gerrno == syscall.EAI_NONAME {
str = noSuchHost
} else if gerrno == syscall.EAI_SYSTEM {
str = syscall.GetErrno().Error()
} else {
str = bytePtrToString(libc_gai_strerror(gerrno))
}
return nil, "", &DNSError{Err: str, Name: name}, true
}
defer libc_freeaddrinfo(res)
if res != nil {
cname = bytePtrToString((*byte)(unsafe.Pointer(res.Ai_canonname)))
if cname == "" {
cname = name
}
if len(cname) > 0 && cname[len(cname)-1] != '.' {
cname += "."
}
}
for r := res; r != nil; r = r.Ai_next {
// Everything comes back twice, once for UDP and once for TCP.
if r.Ai_socktype != syscall.SOCK_STREAM {
continue
}
switch r.Ai_family {
default:
continue
case syscall.AF_INET:
sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(r.Ai_addr))
addrs = append(addrs, copyIP(sa.Addr[:]))
case syscall.AF_INET6:
sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(r.Ai_addr))
addrs = append(addrs, copyIP(sa.Addr[:]))
}
}
return addrs, cname, nil, true
}
func cgoLookupIP(name string) (addrs []IP, err error, completed bool) {
addrs, _, err, completed = cgoLookupIPCNAME(name)
return
}
func cgoLookupCNAME(name string) (cname string, err error, completed bool) {
_, cname, err, completed = cgoLookupIPCNAME(name)
return
}
func copyIP(x IP) IP {
y := make(IP, len(x))
copy(y, x)
return y
}
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