| // Copyright 2009 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. |
| |
| package net |
| |
| import ( |
| "context" |
| "os" |
| "runtime" |
| "syscall" |
| "unsafe" |
| ) |
| |
| const _WSAHOST_NOT_FOUND = syscall.Errno(11001) |
| |
| func winError(call string, err error) error { |
| switch err { |
| case _WSAHOST_NOT_FOUND: |
| return errNoSuchHost |
| } |
| return os.NewSyscallError(call, err) |
| } |
| |
| func getprotobyname(name string) (proto int, err error) { |
| p, err := syscall.GetProtoByName(name) |
| if err != nil { |
| return 0, winError("getprotobyname", err) |
| } |
| return int(p.Proto), nil |
| } |
| |
| // lookupProtocol looks up IP protocol name and returns correspondent protocol number. |
| func lookupProtocol(ctx context.Context, name string) (int, error) { |
| // GetProtoByName return value is stored in thread local storage. |
| // Start new os thread before the call to prevent races. |
| type result struct { |
| proto int |
| err error |
| } |
| ch := make(chan result) // unbuffered |
| go func() { |
| acquireThread() |
| defer releaseThread() |
| runtime.LockOSThread() |
| defer runtime.UnlockOSThread() |
| proto, err := getprotobyname(name) |
| select { |
| case ch <- result{proto: proto, err: err}: |
| case <-ctx.Done(): |
| } |
| }() |
| select { |
| case r := <-ch: |
| if r.err != nil { |
| if proto, err := lookupProtocolMap(name); err == nil { |
| return proto, nil |
| } |
| r.err = &DNSError{Err: r.err.Error(), Name: name} |
| } |
| return r.proto, r.err |
| case <-ctx.Done(): |
| return 0, mapErr(ctx.Err()) |
| } |
| } |
| |
| func (r *Resolver) lookupHost(ctx context.Context, name string) ([]string, error) { |
| ips, err := r.lookupIP(ctx, name) |
| if err != nil { |
| return nil, err |
| } |
| addrs := make([]string, 0, len(ips)) |
| for _, ip := range ips { |
| addrs = append(addrs, ip.String()) |
| } |
| return addrs, nil |
| } |
| |
| func (r *Resolver) lookupIP(ctx context.Context, name string) ([]IPAddr, error) { |
| // TODO(bradfitz,brainman): use ctx more. See TODO below. |
| |
| type ret struct { |
| addrs []IPAddr |
| err error |
| } |
| ch := make(chan ret, 1) |
| go func() { |
| acquireThread() |
| defer releaseThread() |
| hints := syscall.AddrinfoW{ |
| Family: syscall.AF_UNSPEC, |
| Socktype: syscall.SOCK_STREAM, |
| Protocol: syscall.IPPROTO_IP, |
| } |
| var result *syscall.AddrinfoW |
| e := syscall.GetAddrInfoW(syscall.StringToUTF16Ptr(name), nil, &hints, &result) |
| if e != nil { |
| ch <- ret{err: &DNSError{Err: winError("getaddrinfow", e).Error(), Name: name}} |
| } |
| defer syscall.FreeAddrInfoW(result) |
| addrs := make([]IPAddr, 0, 5) |
| for ; result != nil; result = result.Next { |
| addr := unsafe.Pointer(result.Addr) |
| switch result.Family { |
| case syscall.AF_INET: |
| a := (*syscall.RawSockaddrInet4)(addr).Addr |
| addrs = append(addrs, IPAddr{IP: IPv4(a[0], a[1], a[2], a[3])}) |
| case syscall.AF_INET6: |
| a := (*syscall.RawSockaddrInet6)(addr).Addr |
| zone := zoneCache.name(int((*syscall.RawSockaddrInet6)(addr).Scope_id)) |
| addrs = append(addrs, IPAddr{IP: IP{a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], a[14], a[15]}, Zone: zone}) |
| default: |
| ch <- ret{err: &DNSError{Err: syscall.EWINDOWS.Error(), Name: name}} |
| } |
| } |
| ch <- ret{addrs: addrs} |
| }() |
| select { |
| case r := <-ch: |
| return r.addrs, r.err |
| case <-ctx.Done(): |
| // TODO(bradfitz,brainman): cancel the ongoing |
| // GetAddrInfoW? It would require conditionally using |
| // GetAddrInfoEx with lpOverlapped, which requires |
| // Windows 8 or newer. I guess we'll need oldLookupIP, |
| // newLookupIP, and newerLookUP. |
| // |
| // For now we just let it finish and write to the |
| // buffered channel. |
| return nil, &DNSError{ |
| Name: name, |
| Err: ctx.Err().Error(), |
| IsTimeout: ctx.Err() == context.DeadlineExceeded, |
| } |
| } |
| } |
| |
| func (r *Resolver) lookupPort(ctx context.Context, network, service string) (int, error) { |
| if r.PreferGo { |
| return lookupPortMap(network, service) |
| } |
| |
| // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this. |
| acquireThread() |
| defer releaseThread() |
| var stype int32 |
| switch network { |
| case "tcp4", "tcp6": |
| stype = syscall.SOCK_STREAM |
| case "udp4", "udp6": |
| stype = syscall.SOCK_DGRAM |
| } |
| hints := syscall.AddrinfoW{ |
| Family: syscall.AF_UNSPEC, |
| Socktype: stype, |
| Protocol: syscall.IPPROTO_IP, |
| } |
| var result *syscall.AddrinfoW |
| e := syscall.GetAddrInfoW(nil, syscall.StringToUTF16Ptr(service), &hints, &result) |
| if e != nil { |
| if port, err := lookupPortMap(network, service); err == nil { |
| return port, nil |
| } |
| return 0, &DNSError{Err: winError("getaddrinfow", e).Error(), Name: network + "/" + service} |
| } |
| defer syscall.FreeAddrInfoW(result) |
| if result == nil { |
| return 0, &DNSError{Err: syscall.EINVAL.Error(), Name: network + "/" + service} |
| } |
| addr := unsafe.Pointer(result.Addr) |
| switch result.Family { |
| case syscall.AF_INET: |
| a := (*syscall.RawSockaddrInet4)(addr) |
| return int(syscall.Ntohs(a.Port)), nil |
| case syscall.AF_INET6: |
| a := (*syscall.RawSockaddrInet6)(addr) |
| return int(syscall.Ntohs(a.Port)), nil |
| } |
| return 0, &DNSError{Err: syscall.EINVAL.Error(), Name: network + "/" + service} |
| } |
| |
| func (*Resolver) lookupCNAME(ctx context.Context, name string) (string, error) { |
| // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this. |
| acquireThread() |
| defer releaseThread() |
| var r *syscall.DNSRecord |
| e := syscall.DnsQuery(name, syscall.DNS_TYPE_CNAME, 0, nil, &r, nil) |
| // windows returns DNS_INFO_NO_RECORDS if there are no CNAME-s |
| if errno, ok := e.(syscall.Errno); ok && errno == syscall.DNS_INFO_NO_RECORDS { |
| // if there are no aliases, the canonical name is the input name |
| return absDomainName([]byte(name)), nil |
| } |
| if e != nil { |
| return "", &DNSError{Err: winError("dnsquery", e).Error(), Name: name} |
| } |
| defer syscall.DnsRecordListFree(r, 1) |
| |
| resolved := resolveCNAME(syscall.StringToUTF16Ptr(name), r) |
| cname := syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(resolved))[:]) |
| return absDomainName([]byte(cname)), nil |
| } |
| |
| func (*Resolver) lookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) { |
| // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this. |
| acquireThread() |
| defer releaseThread() |
| var target string |
| if service == "" && proto == "" { |
| target = name |
| } else { |
| target = "_" + service + "._" + proto + "." + name |
| } |
| var r *syscall.DNSRecord |
| e := syscall.DnsQuery(target, syscall.DNS_TYPE_SRV, 0, nil, &r, nil) |
| if e != nil { |
| return "", nil, &DNSError{Err: winError("dnsquery", e).Error(), Name: target} |
| } |
| defer syscall.DnsRecordListFree(r, 1) |
| |
| srvs := make([]*SRV, 0, 10) |
| for _, p := range validRecs(r, syscall.DNS_TYPE_SRV, target) { |
| v := (*syscall.DNSSRVData)(unsafe.Pointer(&p.Data[0])) |
| srvs = append(srvs, &SRV{absDomainName([]byte(syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Target))[:]))), v.Port, v.Priority, v.Weight}) |
| } |
| byPriorityWeight(srvs).sort() |
| return absDomainName([]byte(target)), srvs, nil |
| } |
| |
| func (*Resolver) lookupMX(ctx context.Context, name string) ([]*MX, error) { |
| // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this. |
| acquireThread() |
| defer releaseThread() |
| var r *syscall.DNSRecord |
| e := syscall.DnsQuery(name, syscall.DNS_TYPE_MX, 0, nil, &r, nil) |
| if e != nil { |
| return nil, &DNSError{Err: winError("dnsquery", e).Error(), Name: name} |
| } |
| defer syscall.DnsRecordListFree(r, 1) |
| |
| mxs := make([]*MX, 0, 10) |
| for _, p := range validRecs(r, syscall.DNS_TYPE_MX, name) { |
| v := (*syscall.DNSMXData)(unsafe.Pointer(&p.Data[0])) |
| mxs = append(mxs, &MX{absDomainName([]byte(syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.NameExchange))[:]))), v.Preference}) |
| } |
| byPref(mxs).sort() |
| return mxs, nil |
| } |
| |
| func (*Resolver) lookupNS(ctx context.Context, name string) ([]*NS, error) { |
| // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this. |
| acquireThread() |
| defer releaseThread() |
| var r *syscall.DNSRecord |
| e := syscall.DnsQuery(name, syscall.DNS_TYPE_NS, 0, nil, &r, nil) |
| if e != nil { |
| return nil, &DNSError{Err: winError("dnsquery", e).Error(), Name: name} |
| } |
| defer syscall.DnsRecordListFree(r, 1) |
| |
| nss := make([]*NS, 0, 10) |
| for _, p := range validRecs(r, syscall.DNS_TYPE_NS, name) { |
| v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0])) |
| nss = append(nss, &NS{absDomainName([]byte(syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:])))}) |
| } |
| return nss, nil |
| } |
| |
| func (*Resolver) lookupTXT(ctx context.Context, name string) ([]string, error) { |
| // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this. |
| acquireThread() |
| defer releaseThread() |
| var r *syscall.DNSRecord |
| e := syscall.DnsQuery(name, syscall.DNS_TYPE_TEXT, 0, nil, &r, nil) |
| if e != nil { |
| return nil, &DNSError{Err: winError("dnsquery", e).Error(), Name: name} |
| } |
| defer syscall.DnsRecordListFree(r, 1) |
| |
| txts := make([]string, 0, 10) |
| for _, p := range validRecs(r, syscall.DNS_TYPE_TEXT, name) { |
| d := (*syscall.DNSTXTData)(unsafe.Pointer(&p.Data[0])) |
| s := "" |
| for _, v := range (*[1 << 10]*uint16)(unsafe.Pointer(&(d.StringArray[0])))[:d.StringCount] { |
| s += syscall.UTF16ToString((*[1 << 20]uint16)(unsafe.Pointer(v))[:]) |
| } |
| txts = append(txts, s) |
| } |
| return txts, nil |
| } |
| |
| func (*Resolver) lookupAddr(ctx context.Context, addr string) ([]string, error) { |
| // TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this. |
| acquireThread() |
| defer releaseThread() |
| arpa, err := reverseaddr(addr) |
| if err != nil { |
| return nil, err |
| } |
| var r *syscall.DNSRecord |
| e := syscall.DnsQuery(arpa, syscall.DNS_TYPE_PTR, 0, nil, &r, nil) |
| if e != nil { |
| return nil, &DNSError{Err: winError("dnsquery", e).Error(), Name: addr} |
| } |
| defer syscall.DnsRecordListFree(r, 1) |
| |
| ptrs := make([]string, 0, 10) |
| for _, p := range validRecs(r, syscall.DNS_TYPE_PTR, arpa) { |
| v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0])) |
| ptrs = append(ptrs, absDomainName([]byte(syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:])))) |
| } |
| return ptrs, nil |
| } |
| |
| const dnsSectionMask = 0x0003 |
| |
| // returns only results applicable to name and resolves CNAME entries |
| func validRecs(r *syscall.DNSRecord, dnstype uint16, name string) []*syscall.DNSRecord { |
| cname := syscall.StringToUTF16Ptr(name) |
| if dnstype != syscall.DNS_TYPE_CNAME { |
| cname = resolveCNAME(cname, r) |
| } |
| rec := make([]*syscall.DNSRecord, 0, 10) |
| for p := r; p != nil; p = p.Next { |
| if p.Dw&dnsSectionMask != syscall.DnsSectionAnswer { |
| continue |
| } |
| if p.Type != dnstype { |
| continue |
| } |
| if !syscall.DnsNameCompare(cname, p.Name) { |
| continue |
| } |
| rec = append(rec, p) |
| } |
| return rec |
| } |
| |
| // returns the last CNAME in chain |
| func resolveCNAME(name *uint16, r *syscall.DNSRecord) *uint16 { |
| // limit cname resolving to 10 in case of a infinite CNAME loop |
| Cname: |
| for cnameloop := 0; cnameloop < 10; cnameloop++ { |
| for p := r; p != nil; p = p.Next { |
| if p.Dw&dnsSectionMask != syscall.DnsSectionAnswer { |
| continue |
| } |
| if p.Type != syscall.DNS_TYPE_CNAME { |
| continue |
| } |
| if !syscall.DnsNameCompare(name, p.Name) { |
| continue |
| } |
| name = (*syscall.DNSPTRData)(unsafe.Pointer(&r.Data[0])).Host |
| continue Cname |
| } |
| break |
| } |
| return name |
| } |
