src/net/cgo_unix.go - go - Git at Google

 // 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 cgo,!netgo
 // +build darwin dragonfly freebsd linux netbsd openbsd solaris

 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 "C"

 import (
 	"syscall"
 	"unsafe"
 )

 // An addrinfoErrno represents a getaddrinfo, getnameinfo-specific
 // error number. It's a signed number and a zero value is a non-error
 // by convention.
 type addrinfoErrno int

 func (eai addrinfoErrno) Error() string   { return C.GoString(C.gai_strerror(C.int(eai))) }
 func (eai addrinfoErrno) Temporary() bool { return eai == C.EAI_AGAIN }
 func (eai addrinfoErrno) Timeout() bool   { return false }

 func cgoLookupHost(name string) (hosts []string, err error, completed bool) {
 	addrs, err, completed := cgoLookupIP(name)
 	for _, addr := range addrs {
 		hosts = append(hosts, addr.String())
 	}
 	return
 }

 func cgoLookupPort(network, service string) (port int, err error, completed bool) {
 	acquireThread()
 	defer releaseThread()

 	var hints C.struct_addrinfo
 	switch network {
 	case "": // no hints
 	case "tcp", "tcp4", "tcp6":
 		hints.ai_socktype = C.SOCK_STREAM
 		hints.ai_protocol = C.IPPROTO_TCP
 	case "udp", "udp4", "udp6":
 		hints.ai_socktype = C.SOCK_DGRAM
 		hints.ai_protocol = C.IPPROTO_UDP
 	default:
 		return 0, &DNSError{Err: "unknown network", Name: network + "/" + service}, true
 	}
 	if len(network) >= 4 {
 		switch network[3] {
 		case '4':
 			hints.ai_family = C.AF_INET
 		case '6':
 			hints.ai_family = C.AF_INET6
 		}
 	}

 	s := C.CString(service)
 	var res *C.struct_addrinfo
 	defer C.free(unsafe.Pointer(s))
 	gerrno, err := C.getaddrinfo(nil, s, &hints, &res)
 	if gerrno != 0 {
 		switch gerrno {
 		case C.EAI_SYSTEM:
 			if err == nil { // see golang.org/issue/6232
 				err = syscall.EMFILE
 			}
 		default:
 			err = addrinfoErrno(gerrno)
 		}
 		return 0, &DNSError{Err: err.Error(), Name: network + "/" + service}, true
 	}
 	defer C.freeaddrinfo(res)

 	for r := res; r != nil; r = r.ai_next {
 		switch r.ai_family {
 		case C.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 C.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, &DNSError{Err: "unknown port", Name: network + "/" + service}, true
 }

 func cgoLookupIPCNAME(name string) (addrs []IPAddr, cname string, err error, completed bool) {
 	acquireThread()
 	defer releaseThread()

 	var hints C.struct_addrinfo
 	hints.ai_flags = cgoAddrInfoFlags
 	hints.ai_socktype = C.SOCK_STREAM

 	h := C.CString(name)
 	defer C.free(unsafe.Pointer(h))
 	var res *C.struct_addrinfo
 	gerrno, err := C.getaddrinfo(h, nil, &hints, &res)
 	if gerrno != 0 {
 		switch gerrno {
 		case C.EAI_SYSTEM:
 			if err == nil {
 				// 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.
 				err = syscall.EMFILE
 			}
 		case C.EAI_NONAME:
 			err = errNoSuchHost
 		default:
 			err = addrinfoErrno(gerrno)
 		}
 		return nil, "", &DNSError{Err: err.Error(), Name: name}, true
 	}
 	defer C.freeaddrinfo(res)

 	if res != nil {
 		cname = C.GoString(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 != C.SOCK_STREAM {
 			continue
 		}
 		switch r.ai_family {
 		case C.AF_INET:
 			sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(r.ai_addr))
 			addr := IPAddr{IP: copyIP(sa.Addr[:])}
 			addrs = append(addrs, addr)
 		case C.AF_INET6:
 			sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(r.ai_addr))
 			addr := IPAddr{IP: copyIP(sa.Addr[:]), Zone: zoneToString(int(sa.Scope_id))}
 			addrs = append(addrs, addr)
 		}
 	}
 	return addrs, cname, nil, true
 }

 func cgoLookupIP(name string) (addrs []IPAddr, 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
 }

 // These are roughly enough for the following:
 //
 // Source		Encoding			Maximum length of single name entry
 // Unicast DNS		ASCII or			<=253 + a NUL terminator
 //			Unicode in RFC 5892		252 * total number of labels + delimiters + a NUL terminator
 // Multicast DNS	UTF-8 in RFC 5198 or		<=253 + a NUL terminator
 //			the same as unicast DNS ASCII	<=253 + a NUL terminator
 // Local database	various				depends on implementation
 const (
 	nameinfoLen    = 64
 	maxNameinfoLen = 4096
 )

 func cgoLookupPTR(addr string) ([]string, error, bool) {
 	acquireThread()
 	defer releaseThread()

 	var zone string
 	ip := parseIPv4(addr)
 	if ip == nil {
 		ip, zone = parseIPv6(addr, true)
 	}
 	if ip == nil {
 		return nil, &DNSError{Err: "invalid address", Name: addr}, true
 	}
 	sa, salen := cgoSockaddr(ip, zone)
 	if sa == nil {
 		return nil, &DNSError{Err: "invalid address " + ip.String(), Name: addr}, true
 	}
 	var err error
 	var b []byte
 	var gerrno int
 	for l := nameinfoLen; l <= maxNameinfoLen; l *= 2 {
 		b = make([]byte, l)
 		gerrno, err = cgoNameinfoPTR(b, sa, salen)
 		if gerrno == 0 || gerrno != C.EAI_OVERFLOW {
 			break
 		}
 	}
 	if gerrno != 0 {
 		switch gerrno {
 		case C.EAI_SYSTEM:
 			if err == nil { // see golang.org/issue/6232
 				err = syscall.EMFILE
 			}
 		default:
 			err = addrinfoErrno(gerrno)
 		}
 		return nil, &DNSError{Err: err.Error(), Name: addr}, true
 	}

 	for i := 0; i < len(b); i++ {
 		if b[i] == 0 {
 			b = b[:i]
 			break
 		}
 	}
 	return []string{absDomainName(b)}, nil, true
 }

 func cgoSockaddr(ip IP, zone string) (*C.struct_sockaddr, C.socklen_t) {
 	if ip4 := ip.To4(); ip4 != nil {
 		return cgoSockaddrInet4(ip4), C.socklen_t(syscall.SizeofSockaddrInet4)
 	}
 	if ip6 := ip.To16(); ip6 != nil {
 		return cgoSockaddrInet6(ip6, zoneToInt(zone)), C.socklen_t(syscall.SizeofSockaddrInet6)
 	}
 	return nil, 0
 }

 func copyIP(x IP) IP {
 	if len(x) < 16 {
 		return x.To16()
 	}
 	y := make(IP, len(x))
 	copy(y, x)
 	return y
 }
	// 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 cgo,!netgo
	// +build darwin dragonfly freebsd linux netbsd openbsd solaris

	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 "C"

	import (
	"syscall"
	"unsafe"
	)

	// An addrinfoErrno represents a getaddrinfo, getnameinfo-specific
	// error number. It's a signed number and a zero value is a non-error
	// by convention.
	type addrinfoErrno int

	func (eai addrinfoErrno) Error() string { return C.GoString(C.gai_strerror(C.int(eai))) }
	func (eai addrinfoErrno) Temporary() bool { return eai == C.EAI_AGAIN }
	func (eai addrinfoErrno) Timeout() bool { return false }

	func cgoLookupHost(name string) (hosts []string, err error, completed bool) {
	addrs, err, completed := cgoLookupIP(name)
	for _, addr := range addrs {
	hosts = append(hosts, addr.String())
	}
	return
	}

	func cgoLookupPort(network, service string) (port int, err error, completed bool) {
	acquireThread()
	defer releaseThread()

	var hints C.struct_addrinfo
	switch network {
	case "": // no hints
	case "tcp", "tcp4", "tcp6":
	hints.ai_socktype = C.SOCK_STREAM
	hints.ai_protocol = C.IPPROTO_TCP
	case "udp", "udp4", "udp6":
	hints.ai_socktype = C.SOCK_DGRAM
	hints.ai_protocol = C.IPPROTO_UDP
	default:
	return 0, &DNSError{Err: "unknown network", Name: network + "/" + service}, true
	}
	if len(network) >= 4 {
	switch network[3] {
	case '4':
	hints.ai_family = C.AF_INET
	case '6':
	hints.ai_family = C.AF_INET6
	}
	}

	s := C.CString(service)
	var res *C.struct_addrinfo
	defer C.free(unsafe.Pointer(s))
	gerrno, err := C.getaddrinfo(nil, s, &hints, &res)
	if gerrno != 0 {
	switch gerrno {
	case C.EAI_SYSTEM:
	if err == nil { // see golang.org/issue/6232
	err = syscall.EMFILE
	}
	default:
	err = addrinfoErrno(gerrno)
	}
	return 0, &DNSError{Err: err.Error(), Name: network + "/" + service}, true
	}
	defer C.freeaddrinfo(res)

	for r := res; r != nil; r = r.ai_next {
	switch r.ai_family {
	case C.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 C.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, &DNSError{Err: "unknown port", Name: network + "/" + service}, true
	}

	func cgoLookupIPCNAME(name string) (addrs []IPAddr, cname string, err error, completed bool) {
	acquireThread()
	defer releaseThread()

	var hints C.struct_addrinfo
	hints.ai_flags = cgoAddrInfoFlags
	hints.ai_socktype = C.SOCK_STREAM

	h := C.CString(name)
	defer C.free(unsafe.Pointer(h))
	var res *C.struct_addrinfo
	gerrno, err := C.getaddrinfo(h, nil, &hints, &res)
	if gerrno != 0 {
	switch gerrno {
	case C.EAI_SYSTEM:
	if err == nil {
	// 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.
	err = syscall.EMFILE
	}
	case C.EAI_NONAME:
	err = errNoSuchHost
	default:
	err = addrinfoErrno(gerrno)
	}
	return nil, "", &DNSError{Err: err.Error(), Name: name}, true
	}
	defer C.freeaddrinfo(res)

	if res != nil {
	cname = C.GoString(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 != C.SOCK_STREAM {
	continue
	}
	switch r.ai_family {
	case C.AF_INET:
	sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(r.ai_addr))
	addr := IPAddr{IP: copyIP(sa.Addr[:])}
	addrs = append(addrs, addr)
	case C.AF_INET6:
	sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(r.ai_addr))
	addr := IPAddr{IP: copyIP(sa.Addr[:]), Zone: zoneToString(int(sa.Scope_id))}
	addrs = append(addrs, addr)
	}
	}
	return addrs, cname, nil, true
	}

	func cgoLookupIP(name string) (addrs []IPAddr, 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
	}

	// These are roughly enough for the following:
	//
	// Source Encoding Maximum length of single name entry
	// Unicast DNS ASCII or <=253 + a NUL terminator
	// Unicode in RFC 5892 252 * total number of labels + delimiters + a NUL terminator
	// Multicast DNS UTF-8 in RFC 5198 or <=253 + a NUL terminator
	// the same as unicast DNS ASCII <=253 + a NUL terminator
	// Local database various depends on implementation
	const (
	nameinfoLen = 64
	maxNameinfoLen = 4096
	)

	func cgoLookupPTR(addr string) ([]string, error, bool) {
	acquireThread()
	defer releaseThread()

	var zone string
	ip := parseIPv4(addr)
	if ip == nil {
	ip, zone = parseIPv6(addr, true)
	}
	if ip == nil {
	return nil, &DNSError{Err: "invalid address", Name: addr}, true
	}
	sa, salen := cgoSockaddr(ip, zone)
	if sa == nil {
	return nil, &DNSError{Err: "invalid address " + ip.String(), Name: addr}, true
	}
	var err error
	var b []byte
	var gerrno int
	for l := nameinfoLen; l <= maxNameinfoLen; l *= 2 {
	b = make([]byte, l)
	gerrno, err = cgoNameinfoPTR(b, sa, salen)
	if gerrno == 0 \|\| gerrno != C.EAI_OVERFLOW {
	break
	}
	}
	if gerrno != 0 {
	switch gerrno {
	case C.EAI_SYSTEM:
	if err == nil { // see golang.org/issue/6232
	err = syscall.EMFILE
	}
	default:
	err = addrinfoErrno(gerrno)
	}
	return nil, &DNSError{Err: err.Error(), Name: addr}, true
	}

	for i := 0; i < len(b); i++ {
	if b[i] == 0 {
	b = b[:i]
	break
	}
	}
	return []string{absDomainName(b)}, nil, true
	}

	func cgoSockaddr(ip IP, zone string) (*C.struct_sockaddr, C.socklen_t) {
	if ip4 := ip.To4(); ip4 != nil {
	return cgoSockaddrInet4(ip4), C.socklen_t(syscall.SizeofSockaddrInet4)
	}
	if ip6 := ip.To16(); ip6 != nil {
	return cgoSockaddrInet6(ip6, zoneToInt(zone)), C.socklen_t(syscall.SizeofSockaddrInet6)
	}
	return nil, 0
	}

	func copyIP(x IP) IP {
	if len(x) < 16 {
	return x.To16()
	}
	y := make(IP, len(x))
	copy(y, x)
	return y
	}