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-rw-r--r--src/net/cgo_unix.go349
1 files changed, 349 insertions, 0 deletions
diff --git a/src/net/cgo_unix.go b/src/net/cgo_unix.go
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--- /dev/null
+++ b/src/net/cgo_unix.go
@@ -0,0 +1,349 @@
+// 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 aix 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 <unistd.h>
+#include <string.h>
+
+// If nothing else defined EAI_OVERFLOW, make sure it has a value.
+#ifndef EAI_OVERFLOW
+#define EAI_OVERFLOW -12
+#endif
+*/
+import "C"
+
+import (
+ "context"
+ "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 }
+
+type portLookupResult struct {
+ port int
+ err error
+}
+
+type ipLookupResult struct {
+ addrs []IPAddr
+ cname string
+ err error
+}
+
+type reverseLookupResult struct {
+ names []string
+ err error
+}
+
+func cgoLookupHost(ctx context.Context, name string) (hosts []string, err error, completed bool) {
+ addrs, err, completed := cgoLookupIP(ctx, "ip", name)
+ for _, addr := range addrs {
+ hosts = append(hosts, addr.String())
+ }
+ return
+}
+
+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
+ }
+ switch ipVersion(network) {
+ 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 cgoLookupServicePort(hints *C.struct_addrinfo, network, service string) (port int, err error) {
+ cservice := make([]byte, len(service)+1)
+ copy(cservice, service)
+ // Lowercase the C service name.
+ for i, b := range cservice[:len(service)] {
+ cservice[i] = lowerASCII(b)
+ }
+ var res *C.struct_addrinfo
+ gerrno, err := C.getaddrinfo(nil, (*C.char)(unsafe.Pointer(&cservice[0])), hints, &res)
+ if gerrno != 0 {
+ isTemporary := false
+ switch gerrno {
+ case C.EAI_SYSTEM:
+ if err == nil { // see golang.org/issue/6232
+ err = syscall.EMFILE
+ }
+ default:
+ err = addrinfoErrno(gerrno)
+ isTemporary = addrinfoErrno(gerrno).Temporary()
+ }
+ return 0, &DNSError{Err: err.Error(), Name: network + "/" + service, IsTemporary: isTemporary}
+ }
+ 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
+ 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
+ }
+ }
+ return 0, &DNSError{Err: "unknown port", Name: network + "/" + service}
+}
+
+func cgoPortLookup(result chan<- portLookupResult, hints *C.struct_addrinfo, network, service string) {
+ port, err := cgoLookupServicePort(hints, network, service)
+ result <- portLookupResult{port, err}
+}
+
+func cgoLookupIPCNAME(network, name string) (addrs []IPAddr, cname string, err error) {
+ acquireThread()
+ defer releaseThread()
+
+ var hints C.struct_addrinfo
+ hints.ai_flags = cgoAddrInfoFlags
+ hints.ai_socktype = C.SOCK_STREAM
+ hints.ai_family = C.AF_UNSPEC
+ switch ipVersion(network) {
+ case '4':
+ hints.ai_family = C.AF_INET
+ case '6':
+ hints.ai_family = C.AF_INET6
+ }
+
+ h := make([]byte, len(name)+1)
+ copy(h, name)
+ var res *C.struct_addrinfo
+ gerrno, err := C.getaddrinfo((*C.char)(unsafe.Pointer(&h[0])), nil, &hints, &res)
+ if gerrno != 0 {
+ isErrorNoSuchHost := false
+ isTemporary := false
+ 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
+ isErrorNoSuchHost = true
+ default:
+ err = addrinfoErrno(gerrno)
+ isTemporary = addrinfoErrno(gerrno).Temporary()
+ }
+
+ return nil, "", &DNSError{Err: err.Error(), Name: name, IsNotFound: isErrorNoSuchHost, IsTemporary: isTemporary}
+ }
+ 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: zoneCache.name(int(sa.Scope_id))}
+ addrs = append(addrs, addr)
+ }
+ }
+ return addrs, cname, nil
+}
+
+func cgoIPLookup(result chan<- ipLookupResult, network, name string) {
+ addrs, cname, err := cgoLookupIPCNAME(network, name)
+ result <- ipLookupResult{addrs, cname, err}
+}
+
+func cgoLookupIP(ctx context.Context, network, name string) (addrs []IPAddr, err error, completed bool) {
+ if ctx.Done() == nil {
+ addrs, _, err = cgoLookupIPCNAME(network, name)
+ return addrs, err, true
+ }
+ result := make(chan ipLookupResult, 1)
+ go cgoIPLookup(result, network, name)
+ select {
+ case r := <-result:
+ return r.addrs, r.err, true
+ case <-ctx.Done():
+ return nil, mapErr(ctx.Err()), false
+ }
+}
+
+func cgoLookupCNAME(ctx context.Context, name string) (cname string, err error, completed bool) {
+ if ctx.Done() == nil {
+ _, cname, err = cgoLookupIPCNAME("ip", name)
+ return cname, err, true
+ }
+ result := make(chan ipLookupResult, 1)
+ go cgoIPLookup(result, "ip", name)
+ select {
+ case r := <-result:
+ return r.cname, r.err, true
+ case <-ctx.Done():
+ return "", mapErr(ctx.Err()), false
+ }
+}
+
+// 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(ctx context.Context, addr string) (names []string, err error, completed bool) {
+ var zone string
+ ip := parseIPv4(addr)
+ if ip == nil {
+ ip, zone = parseIPv6Zone(addr)
+ }
+ 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
+ }
+ if ctx.Done() == nil {
+ names, err := cgoLookupAddrPTR(addr, sa, salen)
+ return names, err, true
+ }
+ result := make(chan reverseLookupResult, 1)
+ go cgoReverseLookup(result, addr, sa, salen)
+ select {
+ case r := <-result:
+ return r.names, r.err, true
+ case <-ctx.Done():
+ return nil, mapErr(ctx.Err()), false
+ }
+}
+
+func cgoLookupAddrPTR(addr string, sa *C.struct_sockaddr, salen C.socklen_t) (names []string, err error) {
+ acquireThread()
+ defer releaseThread()
+
+ var gerrno int
+ var b []byte
+ 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 {
+ isTemporary := false
+ switch gerrno {
+ case C.EAI_SYSTEM:
+ if err == nil { // see golang.org/issue/6232
+ err = syscall.EMFILE
+ }
+ default:
+ err = addrinfoErrno(gerrno)
+ isTemporary = addrinfoErrno(gerrno).Temporary()
+ }
+ return nil, &DNSError{Err: err.Error(), Name: addr, IsTemporary: isTemporary}
+ }
+ for i := 0; i < len(b); i++ {
+ if b[i] == 0 {
+ b = b[:i]
+ break
+ }
+ }
+ return []string{absDomainName(b)}, nil
+}
+
+func cgoReverseLookup(result chan<- reverseLookupResult, addr string, sa *C.struct_sockaddr, salen C.socklen_t) {
+ names, err := cgoLookupAddrPTR(addr, sa, salen)
+ result <- reverseLookupResult{names, err}
+}
+
+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, zoneCache.index(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
+}