libgo/go/net/cgo_unix.go

   1 // Copyright 2011 The Go Authors.  All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 // +build darwin freebsd linux netbsd openbsd
   6
   7 package net
   8
   9 /*
  10 #include <sys/types.h>
  11 #include <sys/socket.h>
  12 #include <netinet/in.h>
  13 #include <netdb.h>
  14 #include <stdlib.h>
  15 #include <unistd.h>
  16 #include <string.h>
  17 */
  18
  19 import (
  20         "syscall"
  21         "unsafe"
  22 )
  23
  24 //extern getaddrinfo
  25 func libc_getaddrinfo(node *byte, service *byte, hints *syscall.Addrinfo, res **syscall.Addrinfo) int
  26
  27 //extern freeaddrinfo
  28 func libc_freeaddrinfo(res *syscall.Addrinfo)
  29
  30 //extern gai_strerror
  31 func libc_gai_strerror(errcode int) *byte
  32
  33 // bytePtrToString takes a NUL-terminated array of bytes and convert
  34 // it to a Go string.
  35 func bytePtrToString(p *byte) string {
  36         a := (*[10000]byte)(unsafe.Pointer(p))
  37         i := 0
  38         for a[i] != 0 {
  39                 i++
  40         }
  41         return string(a[:i])
  42 }
  43
  44 func cgoLookupHost(name string) (addrs []string, err error, completed bool) {
  45         ip, err, completed := cgoLookupIP(name)
  46         for _, p := range ip {
  47                 addrs = append(addrs, p.String())
  48         }
  49         return
  50 }
  51
  52 func cgoLookupPort(net, service string) (port int, err error, completed bool) {
  53         var res *syscall.Addrinfo
  54         var hints syscall.Addrinfo
  55
  56         switch net {
  57         case "":
  58                 // no hints
  59         case "tcp", "tcp4", "tcp6":
  60                 hints.Ai_socktype = syscall.SOCK_STREAM
  61                 hints.Ai_protocol = syscall.IPPROTO_TCP
  62         case "udp", "udp4", "udp6":
  63                 hints.Ai_socktype = syscall.SOCK_DGRAM
  64                 hints.Ai_protocol = syscall.IPPROTO_UDP
  65         default:
  66                 return 0, UnknownNetworkError(net), true
  67         }
  68         if len(net) >= 4 {
  69                 switch net[3] {
  70                 case '4':
  71                         hints.Ai_family = syscall.AF_INET
  72                 case '6':
  73                         hints.Ai_family = syscall.AF_INET6
  74                 }
  75         }
  76
  77         s := syscall.StringBytePtr(service)
  78         syscall.Entersyscall()
  79         gerrno := libc_getaddrinfo(nil, s, &hints, &res)
  80         syscall.Exitsyscall()
  81         if gerrno == 0 {
  82                 defer libc_freeaddrinfo(res)
  83                 for r := res; r != nil; r = r.Ai_next {
  84                         switch r.Ai_family {
  85                         default:
  86                                 continue
  87                         case syscall.AF_INET:
  88                                 sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(r.Ai_addr))
  89                                 p := (*[2]byte)(unsafe.Pointer(&sa.Port))
  90                                 return int(p[0])<<8 | int(p[1]), nil, true
  91                         case syscall.AF_INET6:
  92                                 sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(r.Ai_addr))
  93                                 p := (*[2]byte)(unsafe.Pointer(&sa.Port))
  94                                 return int(p[0])<<8 | int(p[1]), nil, true
  95                         }
  96                 }
  97         }
  98         return 0, &AddrError{"unknown port", net + "/" + service}, true
  99 }
 100
 101 func cgoLookupIPCNAME(name string) (addrs []IP, cname string, err error, completed bool) {
 102         var res *syscall.Addrinfo
 103         var hints syscall.Addrinfo
 104
 105         hints.Ai_flags = int32(cgoAddrInfoFlags())
 106
 107         h := syscall.StringBytePtr(name)
 108         syscall.Entersyscall()
 109         gerrno := libc_getaddrinfo(h, nil, &hints, &res)
 110         syscall.Exitsyscall()
 111         if gerrno != 0 {
 112                 var str string
 113                 if gerrno == syscall.EAI_NONAME {
 114                         str = noSuchHost
 115                 } else if gerrno == syscall.EAI_SYSTEM {
 116                         str = syscall.GetErrno().Error()
 117                 } else {
 118                         str = bytePtrToString(libc_gai_strerror(gerrno))
 119                 }
 120                 return nil, "", &DNSError{Err: str, Name: name}, true
 121         }
 122         defer libc_freeaddrinfo(res)
 123         if res != nil {
 124                 cname = bytePtrToString((*byte)(unsafe.Pointer(res.Ai_canonname)))
 125                 if cname == "" {
 126                         cname = name
 127                 }
 128                 if len(cname) > 0 && cname[len(cname)-1] != '.' {
 129                         cname += "."
 130                 }
 131         }
 132         for r := res; r != nil; r = r.Ai_next {
 133                 // Everything comes back twice, once for UDP and once for TCP.
 134                 if r.Ai_socktype != syscall.SOCK_STREAM {
 135                         continue
 136                 }
 137                 switch r.Ai_family {
 138                 default:
 139                         continue
 140                 case syscall.AF_INET:
 141                         sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(r.Ai_addr))
 142                         addrs = append(addrs, copyIP(sa.Addr[:]))
 143                 case syscall.AF_INET6:
 144                         sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(r.Ai_addr))
 145                         addrs = append(addrs, copyIP(sa.Addr[:]))
 146                 }
 147         }
 148         return addrs, cname, nil, true
 149 }
 150
 151 func cgoLookupIP(name string) (addrs []IP, err error, completed bool) {
 152         addrs, _, err, completed = cgoLookupIPCNAME(name)
 153         return
 154 }
 155
 156 func cgoLookupCNAME(name string) (cname string, err error, completed bool) {
 157         _, cname, err, completed = cgoLookupIPCNAME(name)
 158         return
 159 }
 160
 161 func copyIP(x IP) IP {
 162         y := make(IP, len(x))
 163         copy(y, x)
 164         return y
 165 }