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
7package 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
19import (
20	"syscall"
21	"unsafe"
22)
23
24//extern getaddrinfo
25func libc_getaddrinfo(node *byte, service *byte, hints *syscall.Addrinfo, res **syscall.Addrinfo) int
26
27//extern freeaddrinfo
28func libc_freeaddrinfo(res *syscall.Addrinfo)
29
30//extern gai_strerror
31func libc_gai_strerror(errcode int) *byte
32
33// bytePtrToString takes a NUL-terminated array of bytes and convert
34// it to a Go string.
35func 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
44func 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
52func 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
101func 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	hints.Ai_socktype = syscall.SOCK_STREAM
107
108	h := syscall.StringBytePtr(name)
109	syscall.Entersyscall()
110	gerrno := libc_getaddrinfo(h, nil, &hints, &res)
111	syscall.Exitsyscall()
112	if gerrno != 0 {
113		var str string
114		if gerrno == syscall.EAI_NONAME {
115			str = noSuchHost
116		} else if gerrno == syscall.EAI_SYSTEM {
117			str = syscall.GetErrno().Error()
118		} else {
119			str = bytePtrToString(libc_gai_strerror(gerrno))
120		}
121		return nil, "", &DNSError{Err: str, Name: name}, true
122	}
123	defer libc_freeaddrinfo(res)
124	if res != nil {
125		cname = bytePtrToString((*byte)(unsafe.Pointer(res.Ai_canonname)))
126		if cname == "" {
127			cname = name
128		}
129		if len(cname) > 0 && cname[len(cname)-1] != '.' {
130			cname += "."
131		}
132	}
133	for r := res; r != nil; r = r.Ai_next {
134		// We only asked for SOCK_STREAM, but check anyhow.
135		if r.Ai_socktype != syscall.SOCK_STREAM {
136			continue
137		}
138		switch r.Ai_family {
139		default:
140			continue
141		case syscall.AF_INET:
142			sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(r.Ai_addr))
143			addrs = append(addrs, copyIP(sa.Addr[:]))
144		case syscall.AF_INET6:
145			sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(r.Ai_addr))
146			addrs = append(addrs, copyIP(sa.Addr[:]))
147		}
148	}
149	return addrs, cname, nil, true
150}
151
152func cgoLookupIP(name string) (addrs []IP, err error, completed bool) {
153	addrs, _, err, completed = cgoLookupIPCNAME(name)
154	return
155}
156
157func cgoLookupCNAME(name string) (cname string, err error, completed bool) {
158	_, cname, err, completed = cgoLookupIPCNAME(name)
159	return
160}
161
162func copyIP(x IP) IP {
163	y := make(IP, len(x))
164	copy(y, x)
165	return y
166}
167