1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
|
// 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 !netgo
// +build darwin dragonfly freebsd linux netbsd openbsd
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) {
acquireThread()
defer releaseThread()
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) {
acquireThread()
defer releaseThread()
var res *syscall.Addrinfo
var hints syscall.Addrinfo
hints.Ai_flags = int32(cgoAddrInfoFlags())
hints.Ai_socktype = syscall.SOCK_STREAM
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 {
errno := syscall.GetErrno()
if errno == 0 {
// err should not be nil, but sometimes getaddrinfo returns
// gerrno == C.EAI_SYSTEM with err == nil on Linux.
// The report claims that it happens when we have too many
// open files, so use syscall.EMFILE (too many open files in system).
// Most system calls would return ENFILE (too many open files),
// so at the least EMFILE should be easy to recognize if this
// comes up again. golang.org/issue/6232.
errno = syscall.EMFILE
}
str = errno.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 {
// We only asked for SOCK_STREAM, but check anyhow.
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 {
if len(x) < 16 {
return x.To16()
}
y := make(IP, len(x))
copy(y, x)
return y
}
|
