func cgoLookupIPCNAME(name string) (addrs []IP, cname string, err error, completed bool) {
var res *C.struct_addrinfo
var hints C.struct_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 = (C.AI_ALL | C.AI_V4MAPPED | C.AI_CANONNAME) & cgoAddrInfoMask()
h := C.CString(name)
defer C.free(unsafe.Pointer(h))
gerrno, err := C.getaddrinfo(h, nil, &hints, &res)
if gerrno != 0 {
var str string
if gerrno == C.EAI_NONAME {
str = noSuchHost
} else if gerrno == C.EAI_SYSTEM {
str = err.Error()
} else {
str = C.GoString(C.gai_strerror(gerrno))
}
return nil, "", &DNSError{Err: str, 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 {
// Everything comes back twice, once for UDP and once for TCP.
if r.ai_socktype != C.SOCK_STREAM {
continue
}
switch r.ai_family {
default:
continue
case C.AF_INET:
sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(r.ai_addr))
addrs = append(addrs, copyIP(sa.Addr[:]))
case C.AF_INET6:
sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(r.ai_addr))
addrs = append(addrs, copyIP(sa.Addr[:]))
}
}
return addrs, cname, nil, true
}
func cgoLookupIPCNAME(name string) (addrs []IP, cname string, err error, completed bool) {
acquireThread()
defer releaseThread()
var res *C.struct_addrinfo
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))
gerrno, err := C.getaddrinfo(h, nil, &hints, &res)
if gerrno != 0 {
var str string
if gerrno == C.EAI_NONAME {
str = noSuchHost
} else if gerrno == C.EAI_SYSTEM {
str = err.Error()
} else {
str = C.GoString(C.gai_strerror(gerrno))
}
return nil, "", &DNSError{Err: str, 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 {
default:
continue
case C.AF_INET:
sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(r.ai_addr))
addrs = append(addrs, copyIP(sa.Addr[:]))
case C.AF_INET6:
sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(r.ai_addr))
addrs = append(addrs, copyIP(sa.Addr[:]))
}
}
return addrs, cname, nil, true
}
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 cgoLookupPort(net, service string) (port int, err error, completed bool) {
acquireThread()
defer releaseThread()
var res *C.struct_addrinfo
var hints C.struct_addrinfo
switch net {
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, UnknownNetworkError(net), true
}
if len(net) >= 4 {
switch net[3] {
case '4':
hints.ai_family = C.AF_INET
case '6':
hints.ai_family = C.AF_INET6
}
}
s := C.CString(service)
defer C.free(unsafe.Pointer(s))
if C.getaddrinfo(nil, s, &hints, &res) == 0 {
defer C.freeaddrinfo(res)
for r := res; r != nil; r = r.ai_next {
switch r.ai_family {
default:
continue
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, &AddrError{"unknown port", net + "/" + service}, true
}
func cgoLookupPort(ctx context.Context, network, service string) (port int, err error, completed bool) {
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
}
}
if ctx.Done() == nil {
port, err := cgoLookupServicePort(&hints, network, service)
return port, err, true
}
result := make(chan portLookupResult, 1)
go cgoPortLookup(result, &hints, network, service)
select {
case r := <-result:
return r.port, r.err, true
case <-ctx.Done():
// Since there isn't a portable way to cancel the lookup,
// we just let it finish and write to the buffered channel.
return 0, mapErr(ctx.Err()), false
}
}
func cgoLookupIPCNAME(name string) (addrs []IPAddr, cname string, err error, completed bool) {
acquireThread()
defer releaseThread()
var res *C.struct_addrinfo
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))
gerrno, err := C.getaddrinfo(h, nil, &hints, &res)
if gerrno != 0 {
var str string
if gerrno == C.EAI_NONAME {
str = noSuchHost
} else if gerrno == 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
}
str = err.Error()
} else {
str = C.GoString(C.gai_strerror(gerrno))
}
return nil, "", &DNSError{Err: str, 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 {
default:
continue
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
}