| // 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 ( |
| "os" |
| "runtime" |
| "syscall" |
| "unsafe" |
| ) |
| |
| var ( |
| lookupPort = oldLookupPort |
| lookupIP = oldLookupIP |
| ) |
| |
| func getprotobyname(name string) (proto int, err error) { |
| p, err := syscall.GetProtoByName(name) |
| if err != nil { |
| return 0, os.NewSyscallError("getorotobyname", err) |
| } |
| return int(p.Proto), nil |
| } |
| |
| // lookupProtocol looks up IP protocol name and returns correspondent protocol number. |
| func lookupProtocol(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) |
| go func() { |
| acquireThread() |
| defer releaseThread() |
| runtime.LockOSThread() |
| defer runtime.UnlockOSThread() |
| proto, err := getprotobyname(name) |
| ch <- result{proto: proto, err: err} |
| }() |
| r := <-ch |
| if r.err != nil { |
| if proto, ok := protocols[name]; ok { |
| return proto, nil |
| } |
| r.err = &DNSError{Err: r.err.Error(), Name: name} |
| } |
| return r.proto, r.err |
| } |
| |
| func lookupHost(name string) ([]string, error) { |
| ips, err := LookupIP(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 gethostbyname(name string) (addrs []IPAddr, err error) { |
| // caller already acquired thread |
| h, err := syscall.GetHostByName(name) |
| if err != nil { |
| return nil, os.NewSyscallError("gethostbyname", err) |
| } |
| switch h.AddrType { |
| case syscall.AF_INET: |
| i := 0 |
| addrs = make([]IPAddr, 100) // plenty of room to grow |
| for p := (*[100](*[4]byte))(unsafe.Pointer(h.AddrList)); i < cap(addrs) && p[i] != nil; i++ { |
| addrs[i] = IPAddr{IP: IPv4(p[i][0], p[i][1], p[i][2], p[i][3])} |
| } |
| addrs = addrs[0:i] |
| default: // TODO(vcc): Implement non IPv4 address lookups. |
| return nil, syscall.EWINDOWS |
| } |
| return addrs, nil |
| } |
| |
| func oldLookupIP(name string) ([]IPAddr, error) { |
| // GetHostByName return value is stored in thread local storage. |
| // Start new os thread before the call to prevent races. |
| type result struct { |
| addrs []IPAddr |
| err error |
| } |
| ch := make(chan result) |
| go func() { |
| acquireThread() |
| defer releaseThread() |
| runtime.LockOSThread() |
| defer runtime.UnlockOSThread() |
| addrs, err := gethostbyname(name) |
| ch <- result{addrs: addrs, err: err} |
| }() |
| r := <-ch |
| if r.err != nil { |
| r.err = &DNSError{Err: r.err.Error(), Name: name} |
| } |
| return r.addrs, r.err |
| } |
| |
| func newLookupIP(name string) ([]IPAddr, error) { |
| 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 { |
| return nil, &DNSError{Err: os.NewSyscallError("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 := zoneToString(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: |
| return nil, &DNSError{Err: syscall.EWINDOWS.Error(), Name: name} |
| } |
| } |
| return addrs, nil |
| } |
| |
| func getservbyname(network, service string) (int, error) { |
| acquireThread() |
| defer releaseThread() |
| switch network { |
| case "tcp4", "tcp6": |
| network = "tcp" |
| case "udp4", "udp6": |
| network = "udp" |
| } |
| s, err := syscall.GetServByName(service, network) |
| if err != nil { |
| return 0, os.NewSyscallError("getservbyname", err) |
| } |
| return int(syscall.Ntohs(s.Port)), nil |
| } |
| |
| func oldLookupPort(network, service string) (int, error) { |
| // GetServByName return value is stored in thread local storage. |
| // Start new os thread before the call to prevent races. |
| type result struct { |
| port int |
| err error |
| } |
| ch := make(chan result) |
| go func() { |
| acquireThread() |
| defer releaseThread() |
| runtime.LockOSThread() |
| defer runtime.UnlockOSThread() |
| port, err := getservbyname(network, service) |
| ch <- result{port: port, err: err} |
| }() |
| r := <-ch |
| if r.err != nil { |
| r.err = &DNSError{Err: r.err.Error(), Name: network + "/" + service} |
| } |
| return r.port, r.err |
| } |
| |
| func newLookupPort(network, service string) (int, error) { |
| 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 { |
| return 0, &DNSError{Err: os.NewSyscallError("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 lookupCNAME(name string) (string, error) { |
| 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 |
| if name == "" || name[len(name)-1] != '.' { |
| return name + ".", nil |
| } |
| return name, nil |
| } |
| if e != nil { |
| return "", &DNSError{Err: os.NewSyscallError("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 cname, nil |
| } |
| |
| func lookupSRV(service, proto, name string) (string, []*SRV, error) { |
| 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: os.NewSyscallError("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{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Target))[:]), v.Port, v.Priority, v.Weight}) |
| } |
| byPriorityWeight(srvs).sort() |
| return name, srvs, nil |
| } |
| |
| func lookupMX(name string) ([]*MX, error) { |
| 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: os.NewSyscallError("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{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.NameExchange))[:]) + ".", v.Preference}) |
| } |
| byPref(mxs).sort() |
| return mxs, nil |
| } |
| |
| func lookupNS(name string) ([]*NS, error) { |
| 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: os.NewSyscallError("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{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]) + "."}) |
| } |
| return nss, nil |
| } |
| |
| func lookupTXT(name string) ([]string, error) { |
| 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: os.NewSyscallError("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])) |
| 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 lookupAddr(addr string) ([]string, error) { |
| 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: os.NewSyscallError("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, 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 |
| } |
