mirror of
https://github.com/go-gitea/gitea.git
synced 2024-08-22 12:33:27 +02:00
829 lines
22 KiB
Go
Vendored
829 lines
22 KiB
Go
Vendored
// DNS server implementation.
|
|
|
|
package dns
|
|
|
|
import (
|
|
"context"
|
|
"crypto/tls"
|
|
"encoding/binary"
|
|
"errors"
|
|
"io"
|
|
"net"
|
|
"strings"
|
|
"sync"
|
|
"time"
|
|
)
|
|
|
|
// Default maximum number of TCP queries before we close the socket.
|
|
const maxTCPQueries = 128
|
|
|
|
// aLongTimeAgo is a non-zero time, far in the past, used for
|
|
// immediate cancelation of network operations.
|
|
var aLongTimeAgo = time.Unix(1, 0)
|
|
|
|
// Handler is implemented by any value that implements ServeDNS.
|
|
type Handler interface {
|
|
ServeDNS(w ResponseWriter, r *Msg)
|
|
}
|
|
|
|
// The HandlerFunc type is an adapter to allow the use of
|
|
// ordinary functions as DNS handlers. If f is a function
|
|
// with the appropriate signature, HandlerFunc(f) is a
|
|
// Handler object that calls f.
|
|
type HandlerFunc func(ResponseWriter, *Msg)
|
|
|
|
// ServeDNS calls f(w, r).
|
|
func (f HandlerFunc) ServeDNS(w ResponseWriter, r *Msg) {
|
|
f(w, r)
|
|
}
|
|
|
|
// A ResponseWriter interface is used by an DNS handler to
|
|
// construct an DNS response.
|
|
type ResponseWriter interface {
|
|
// LocalAddr returns the net.Addr of the server
|
|
LocalAddr() net.Addr
|
|
// RemoteAddr returns the net.Addr of the client that sent the current request.
|
|
RemoteAddr() net.Addr
|
|
// WriteMsg writes a reply back to the client.
|
|
WriteMsg(*Msg) error
|
|
// Write writes a raw buffer back to the client.
|
|
Write([]byte) (int, error)
|
|
// Close closes the connection.
|
|
Close() error
|
|
// TsigStatus returns the status of the Tsig.
|
|
TsigStatus() error
|
|
// TsigTimersOnly sets the tsig timers only boolean.
|
|
TsigTimersOnly(bool)
|
|
// Hijack lets the caller take over the connection.
|
|
// After a call to Hijack(), the DNS package will not do anything with the connection.
|
|
Hijack()
|
|
}
|
|
|
|
// A ConnectionStater interface is used by a DNS Handler to access TLS connection state
|
|
// when available.
|
|
type ConnectionStater interface {
|
|
ConnectionState() *tls.ConnectionState
|
|
}
|
|
|
|
type response struct {
|
|
closed bool // connection has been closed
|
|
hijacked bool // connection has been hijacked by handler
|
|
tsigTimersOnly bool
|
|
tsigStatus error
|
|
tsigRequestMAC string
|
|
tsigSecret map[string]string // the tsig secrets
|
|
udp net.PacketConn // i/o connection if UDP was used
|
|
tcp net.Conn // i/o connection if TCP was used
|
|
udpSession *SessionUDP // oob data to get egress interface right
|
|
pcSession net.Addr // address to use when writing to a generic net.PacketConn
|
|
writer Writer // writer to output the raw DNS bits
|
|
}
|
|
|
|
// handleRefused returns a HandlerFunc that returns REFUSED for every request it gets.
|
|
func handleRefused(w ResponseWriter, r *Msg) {
|
|
m := new(Msg)
|
|
m.SetRcode(r, RcodeRefused)
|
|
w.WriteMsg(m)
|
|
}
|
|
|
|
// HandleFailed returns a HandlerFunc that returns SERVFAIL for every request it gets.
|
|
// Deprecated: This function is going away.
|
|
func HandleFailed(w ResponseWriter, r *Msg) {
|
|
m := new(Msg)
|
|
m.SetRcode(r, RcodeServerFailure)
|
|
// does not matter if this write fails
|
|
w.WriteMsg(m)
|
|
}
|
|
|
|
// ListenAndServe Starts a server on address and network specified Invoke handler
|
|
// for incoming queries.
|
|
func ListenAndServe(addr string, network string, handler Handler) error {
|
|
server := &Server{Addr: addr, Net: network, Handler: handler}
|
|
return server.ListenAndServe()
|
|
}
|
|
|
|
// ListenAndServeTLS acts like http.ListenAndServeTLS, more information in
|
|
// http://golang.org/pkg/net/http/#ListenAndServeTLS
|
|
func ListenAndServeTLS(addr, certFile, keyFile string, handler Handler) error {
|
|
cert, err := tls.LoadX509KeyPair(certFile, keyFile)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
config := tls.Config{
|
|
Certificates: []tls.Certificate{cert},
|
|
}
|
|
|
|
server := &Server{
|
|
Addr: addr,
|
|
Net: "tcp-tls",
|
|
TLSConfig: &config,
|
|
Handler: handler,
|
|
}
|
|
|
|
return server.ListenAndServe()
|
|
}
|
|
|
|
// ActivateAndServe activates a server with a listener from systemd,
|
|
// l and p should not both be non-nil.
|
|
// If both l and p are not nil only p will be used.
|
|
// Invoke handler for incoming queries.
|
|
func ActivateAndServe(l net.Listener, p net.PacketConn, handler Handler) error {
|
|
server := &Server{Listener: l, PacketConn: p, Handler: handler}
|
|
return server.ActivateAndServe()
|
|
}
|
|
|
|
// Writer writes raw DNS messages; each call to Write should send an entire message.
|
|
type Writer interface {
|
|
io.Writer
|
|
}
|
|
|
|
// Reader reads raw DNS messages; each call to ReadTCP or ReadUDP should return an entire message.
|
|
type Reader interface {
|
|
// ReadTCP reads a raw message from a TCP connection. Implementations may alter
|
|
// connection properties, for example the read-deadline.
|
|
ReadTCP(conn net.Conn, timeout time.Duration) ([]byte, error)
|
|
// ReadUDP reads a raw message from a UDP connection. Implementations may alter
|
|
// connection properties, for example the read-deadline.
|
|
ReadUDP(conn *net.UDPConn, timeout time.Duration) ([]byte, *SessionUDP, error)
|
|
}
|
|
|
|
// PacketConnReader is an optional interface that Readers can implement to support using generic net.PacketConns.
|
|
type PacketConnReader interface {
|
|
Reader
|
|
|
|
// ReadPacketConn reads a raw message from a generic net.PacketConn UDP connection. Implementations may
|
|
// alter connection properties, for example the read-deadline.
|
|
ReadPacketConn(conn net.PacketConn, timeout time.Duration) ([]byte, net.Addr, error)
|
|
}
|
|
|
|
// defaultReader is an adapter for the Server struct that implements the Reader and
|
|
// PacketConnReader interfaces using the readTCP, readUDP and readPacketConn funcs
|
|
// of the embedded Server.
|
|
type defaultReader struct {
|
|
*Server
|
|
}
|
|
|
|
var _ PacketConnReader = defaultReader{}
|
|
|
|
func (dr defaultReader) ReadTCP(conn net.Conn, timeout time.Duration) ([]byte, error) {
|
|
return dr.readTCP(conn, timeout)
|
|
}
|
|
|
|
func (dr defaultReader) ReadUDP(conn *net.UDPConn, timeout time.Duration) ([]byte, *SessionUDP, error) {
|
|
return dr.readUDP(conn, timeout)
|
|
}
|
|
|
|
func (dr defaultReader) ReadPacketConn(conn net.PacketConn, timeout time.Duration) ([]byte, net.Addr, error) {
|
|
return dr.readPacketConn(conn, timeout)
|
|
}
|
|
|
|
// DecorateReader is a decorator hook for extending or supplanting the functionality of a Reader.
|
|
// Implementations should never return a nil Reader.
|
|
// Readers should also implement the optional PacketConnReader interface.
|
|
// PacketConnReader is required to use a generic net.PacketConn.
|
|
type DecorateReader func(Reader) Reader
|
|
|
|
// DecorateWriter is a decorator hook for extending or supplanting the functionality of a Writer.
|
|
// Implementations should never return a nil Writer.
|
|
type DecorateWriter func(Writer) Writer
|
|
|
|
// A Server defines parameters for running an DNS server.
|
|
type Server struct {
|
|
// Address to listen on, ":dns" if empty.
|
|
Addr string
|
|
// if "tcp" or "tcp-tls" (DNS over TLS) it will invoke a TCP listener, otherwise an UDP one
|
|
Net string
|
|
// TCP Listener to use, this is to aid in systemd's socket activation.
|
|
Listener net.Listener
|
|
// TLS connection configuration
|
|
TLSConfig *tls.Config
|
|
// UDP "Listener" to use, this is to aid in systemd's socket activation.
|
|
PacketConn net.PacketConn
|
|
// Handler to invoke, dns.DefaultServeMux if nil.
|
|
Handler Handler
|
|
// Default buffer size to use to read incoming UDP messages. If not set
|
|
// it defaults to MinMsgSize (512 B).
|
|
UDPSize int
|
|
// The net.Conn.SetReadTimeout value for new connections, defaults to 2 * time.Second.
|
|
ReadTimeout time.Duration
|
|
// The net.Conn.SetWriteTimeout value for new connections, defaults to 2 * time.Second.
|
|
WriteTimeout time.Duration
|
|
// TCP idle timeout for multiple queries, if nil, defaults to 8 * time.Second (RFC 5966).
|
|
IdleTimeout func() time.Duration
|
|
// Secret(s) for Tsig map[<zonename>]<base64 secret>. The zonename must be in canonical form (lowercase, fqdn, see RFC 4034 Section 6.2).
|
|
TsigSecret map[string]string
|
|
// If NotifyStartedFunc is set it is called once the server has started listening.
|
|
NotifyStartedFunc func()
|
|
// DecorateReader is optional, allows customization of the process that reads raw DNS messages.
|
|
DecorateReader DecorateReader
|
|
// DecorateWriter is optional, allows customization of the process that writes raw DNS messages.
|
|
DecorateWriter DecorateWriter
|
|
// Maximum number of TCP queries before we close the socket. Default is maxTCPQueries (unlimited if -1).
|
|
MaxTCPQueries int
|
|
// Whether to set the SO_REUSEPORT socket option, allowing multiple listeners to be bound to a single address.
|
|
// It is only supported on go1.11+ and when using ListenAndServe.
|
|
ReusePort bool
|
|
// AcceptMsgFunc will check the incoming message and will reject it early in the process.
|
|
// By default DefaultMsgAcceptFunc will be used.
|
|
MsgAcceptFunc MsgAcceptFunc
|
|
|
|
// Shutdown handling
|
|
lock sync.RWMutex
|
|
started bool
|
|
shutdown chan struct{}
|
|
conns map[net.Conn]struct{}
|
|
|
|
// A pool for UDP message buffers.
|
|
udpPool sync.Pool
|
|
}
|
|
|
|
func (srv *Server) isStarted() bool {
|
|
srv.lock.RLock()
|
|
started := srv.started
|
|
srv.lock.RUnlock()
|
|
return started
|
|
}
|
|
|
|
func makeUDPBuffer(size int) func() interface{} {
|
|
return func() interface{} {
|
|
return make([]byte, size)
|
|
}
|
|
}
|
|
|
|
func (srv *Server) init() {
|
|
srv.shutdown = make(chan struct{})
|
|
srv.conns = make(map[net.Conn]struct{})
|
|
|
|
if srv.UDPSize == 0 {
|
|
srv.UDPSize = MinMsgSize
|
|
}
|
|
if srv.MsgAcceptFunc == nil {
|
|
srv.MsgAcceptFunc = DefaultMsgAcceptFunc
|
|
}
|
|
if srv.Handler == nil {
|
|
srv.Handler = DefaultServeMux
|
|
}
|
|
|
|
srv.udpPool.New = makeUDPBuffer(srv.UDPSize)
|
|
}
|
|
|
|
func unlockOnce(l sync.Locker) func() {
|
|
var once sync.Once
|
|
return func() { once.Do(l.Unlock) }
|
|
}
|
|
|
|
// ListenAndServe starts a nameserver on the configured address in *Server.
|
|
func (srv *Server) ListenAndServe() error {
|
|
unlock := unlockOnce(&srv.lock)
|
|
srv.lock.Lock()
|
|
defer unlock()
|
|
|
|
if srv.started {
|
|
return &Error{err: "server already started"}
|
|
}
|
|
|
|
addr := srv.Addr
|
|
if addr == "" {
|
|
addr = ":domain"
|
|
}
|
|
|
|
srv.init()
|
|
|
|
switch srv.Net {
|
|
case "tcp", "tcp4", "tcp6":
|
|
l, err := listenTCP(srv.Net, addr, srv.ReusePort)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
srv.Listener = l
|
|
srv.started = true
|
|
unlock()
|
|
return srv.serveTCP(l)
|
|
case "tcp-tls", "tcp4-tls", "tcp6-tls":
|
|
if srv.TLSConfig == nil || (len(srv.TLSConfig.Certificates) == 0 && srv.TLSConfig.GetCertificate == nil) {
|
|
return errors.New("dns: neither Certificates nor GetCertificate set in Config")
|
|
}
|
|
network := strings.TrimSuffix(srv.Net, "-tls")
|
|
l, err := listenTCP(network, addr, srv.ReusePort)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
l = tls.NewListener(l, srv.TLSConfig)
|
|
srv.Listener = l
|
|
srv.started = true
|
|
unlock()
|
|
return srv.serveTCP(l)
|
|
case "udp", "udp4", "udp6":
|
|
l, err := listenUDP(srv.Net, addr, srv.ReusePort)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
u := l.(*net.UDPConn)
|
|
if e := setUDPSocketOptions(u); e != nil {
|
|
u.Close()
|
|
return e
|
|
}
|
|
srv.PacketConn = l
|
|
srv.started = true
|
|
unlock()
|
|
return srv.serveUDP(u)
|
|
}
|
|
return &Error{err: "bad network"}
|
|
}
|
|
|
|
// ActivateAndServe starts a nameserver with the PacketConn or Listener
|
|
// configured in *Server. Its main use is to start a server from systemd.
|
|
func (srv *Server) ActivateAndServe() error {
|
|
unlock := unlockOnce(&srv.lock)
|
|
srv.lock.Lock()
|
|
defer unlock()
|
|
|
|
if srv.started {
|
|
return &Error{err: "server already started"}
|
|
}
|
|
|
|
srv.init()
|
|
|
|
if srv.PacketConn != nil {
|
|
// Check PacketConn interface's type is valid and value
|
|
// is not nil
|
|
if t, ok := srv.PacketConn.(*net.UDPConn); ok && t != nil {
|
|
if e := setUDPSocketOptions(t); e != nil {
|
|
return e
|
|
}
|
|
}
|
|
srv.started = true
|
|
unlock()
|
|
return srv.serveUDP(srv.PacketConn)
|
|
}
|
|
if srv.Listener != nil {
|
|
srv.started = true
|
|
unlock()
|
|
return srv.serveTCP(srv.Listener)
|
|
}
|
|
return &Error{err: "bad listeners"}
|
|
}
|
|
|
|
// Shutdown shuts down a server. After a call to Shutdown, ListenAndServe and
|
|
// ActivateAndServe will return.
|
|
func (srv *Server) Shutdown() error {
|
|
return srv.ShutdownContext(context.Background())
|
|
}
|
|
|
|
// ShutdownContext shuts down a server. After a call to ShutdownContext,
|
|
// ListenAndServe and ActivateAndServe will return.
|
|
//
|
|
// A context.Context may be passed to limit how long to wait for connections
|
|
// to terminate.
|
|
func (srv *Server) ShutdownContext(ctx context.Context) error {
|
|
srv.lock.Lock()
|
|
if !srv.started {
|
|
srv.lock.Unlock()
|
|
return &Error{err: "server not started"}
|
|
}
|
|
|
|
srv.started = false
|
|
|
|
if srv.PacketConn != nil {
|
|
srv.PacketConn.SetReadDeadline(aLongTimeAgo) // Unblock reads
|
|
}
|
|
|
|
if srv.Listener != nil {
|
|
srv.Listener.Close()
|
|
}
|
|
|
|
for rw := range srv.conns {
|
|
rw.SetReadDeadline(aLongTimeAgo) // Unblock reads
|
|
}
|
|
|
|
srv.lock.Unlock()
|
|
|
|
if testShutdownNotify != nil {
|
|
testShutdownNotify.Broadcast()
|
|
}
|
|
|
|
var ctxErr error
|
|
select {
|
|
case <-srv.shutdown:
|
|
case <-ctx.Done():
|
|
ctxErr = ctx.Err()
|
|
}
|
|
|
|
if srv.PacketConn != nil {
|
|
srv.PacketConn.Close()
|
|
}
|
|
|
|
return ctxErr
|
|
}
|
|
|
|
var testShutdownNotify *sync.Cond
|
|
|
|
// getReadTimeout is a helper func to use system timeout if server did not intend to change it.
|
|
func (srv *Server) getReadTimeout() time.Duration {
|
|
if srv.ReadTimeout != 0 {
|
|
return srv.ReadTimeout
|
|
}
|
|
return dnsTimeout
|
|
}
|
|
|
|
// serveTCP starts a TCP listener for the server.
|
|
func (srv *Server) serveTCP(l net.Listener) error {
|
|
defer l.Close()
|
|
|
|
if srv.NotifyStartedFunc != nil {
|
|
srv.NotifyStartedFunc()
|
|
}
|
|
|
|
var wg sync.WaitGroup
|
|
defer func() {
|
|
wg.Wait()
|
|
close(srv.shutdown)
|
|
}()
|
|
|
|
for srv.isStarted() {
|
|
rw, err := l.Accept()
|
|
if err != nil {
|
|
if !srv.isStarted() {
|
|
return nil
|
|
}
|
|
if neterr, ok := err.(net.Error); ok && neterr.Temporary() {
|
|
continue
|
|
}
|
|
return err
|
|
}
|
|
srv.lock.Lock()
|
|
// Track the connection to allow unblocking reads on shutdown.
|
|
srv.conns[rw] = struct{}{}
|
|
srv.lock.Unlock()
|
|
wg.Add(1)
|
|
go srv.serveTCPConn(&wg, rw)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// serveUDP starts a UDP listener for the server.
|
|
func (srv *Server) serveUDP(l net.PacketConn) error {
|
|
defer l.Close()
|
|
|
|
reader := Reader(defaultReader{srv})
|
|
if srv.DecorateReader != nil {
|
|
reader = srv.DecorateReader(reader)
|
|
}
|
|
|
|
lUDP, isUDP := l.(*net.UDPConn)
|
|
readerPC, canPacketConn := reader.(PacketConnReader)
|
|
if !isUDP && !canPacketConn {
|
|
return &Error{err: "PacketConnReader was not implemented on Reader returned from DecorateReader but is required for net.PacketConn"}
|
|
}
|
|
|
|
if srv.NotifyStartedFunc != nil {
|
|
srv.NotifyStartedFunc()
|
|
}
|
|
|
|
var wg sync.WaitGroup
|
|
defer func() {
|
|
wg.Wait()
|
|
close(srv.shutdown)
|
|
}()
|
|
|
|
rtimeout := srv.getReadTimeout()
|
|
// deadline is not used here
|
|
for srv.isStarted() {
|
|
var (
|
|
m []byte
|
|
sPC net.Addr
|
|
sUDP *SessionUDP
|
|
err error
|
|
)
|
|
if isUDP {
|
|
m, sUDP, err = reader.ReadUDP(lUDP, rtimeout)
|
|
} else {
|
|
m, sPC, err = readerPC.ReadPacketConn(l, rtimeout)
|
|
}
|
|
if err != nil {
|
|
if !srv.isStarted() {
|
|
return nil
|
|
}
|
|
if netErr, ok := err.(net.Error); ok && netErr.Temporary() {
|
|
continue
|
|
}
|
|
return err
|
|
}
|
|
if len(m) < headerSize {
|
|
if cap(m) == srv.UDPSize {
|
|
srv.udpPool.Put(m[:srv.UDPSize])
|
|
}
|
|
continue
|
|
}
|
|
wg.Add(1)
|
|
go srv.serveUDPPacket(&wg, m, l, sUDP, sPC)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Serve a new TCP connection.
|
|
func (srv *Server) serveTCPConn(wg *sync.WaitGroup, rw net.Conn) {
|
|
w := &response{tsigSecret: srv.TsigSecret, tcp: rw}
|
|
if srv.DecorateWriter != nil {
|
|
w.writer = srv.DecorateWriter(w)
|
|
} else {
|
|
w.writer = w
|
|
}
|
|
|
|
reader := Reader(defaultReader{srv})
|
|
if srv.DecorateReader != nil {
|
|
reader = srv.DecorateReader(reader)
|
|
}
|
|
|
|
idleTimeout := tcpIdleTimeout
|
|
if srv.IdleTimeout != nil {
|
|
idleTimeout = srv.IdleTimeout()
|
|
}
|
|
|
|
timeout := srv.getReadTimeout()
|
|
|
|
limit := srv.MaxTCPQueries
|
|
if limit == 0 {
|
|
limit = maxTCPQueries
|
|
}
|
|
|
|
for q := 0; (q < limit || limit == -1) && srv.isStarted(); q++ {
|
|
m, err := reader.ReadTCP(w.tcp, timeout)
|
|
if err != nil {
|
|
// TODO(tmthrgd): handle error
|
|
break
|
|
}
|
|
srv.serveDNS(m, w)
|
|
if w.closed {
|
|
break // Close() was called
|
|
}
|
|
if w.hijacked {
|
|
break // client will call Close() themselves
|
|
}
|
|
// The first read uses the read timeout, the rest use the
|
|
// idle timeout.
|
|
timeout = idleTimeout
|
|
}
|
|
|
|
if !w.hijacked {
|
|
w.Close()
|
|
}
|
|
|
|
srv.lock.Lock()
|
|
delete(srv.conns, w.tcp)
|
|
srv.lock.Unlock()
|
|
|
|
wg.Done()
|
|
}
|
|
|
|
// Serve a new UDP request.
|
|
func (srv *Server) serveUDPPacket(wg *sync.WaitGroup, m []byte, u net.PacketConn, udpSession *SessionUDP, pcSession net.Addr) {
|
|
w := &response{tsigSecret: srv.TsigSecret, udp: u, udpSession: udpSession, pcSession: pcSession}
|
|
if srv.DecorateWriter != nil {
|
|
w.writer = srv.DecorateWriter(w)
|
|
} else {
|
|
w.writer = w
|
|
}
|
|
|
|
srv.serveDNS(m, w)
|
|
wg.Done()
|
|
}
|
|
|
|
func (srv *Server) serveDNS(m []byte, w *response) {
|
|
dh, off, err := unpackMsgHdr(m, 0)
|
|
if err != nil {
|
|
// Let client hang, they are sending crap; any reply can be used to amplify.
|
|
return
|
|
}
|
|
|
|
req := new(Msg)
|
|
req.setHdr(dh)
|
|
|
|
switch action := srv.MsgAcceptFunc(dh); action {
|
|
case MsgAccept:
|
|
if req.unpack(dh, m, off) == nil {
|
|
break
|
|
}
|
|
|
|
fallthrough
|
|
case MsgReject, MsgRejectNotImplemented:
|
|
opcode := req.Opcode
|
|
req.SetRcodeFormatError(req)
|
|
req.Zero = false
|
|
if action == MsgRejectNotImplemented {
|
|
req.Opcode = opcode
|
|
req.Rcode = RcodeNotImplemented
|
|
}
|
|
|
|
// Are we allowed to delete any OPT records here?
|
|
req.Ns, req.Answer, req.Extra = nil, nil, nil
|
|
|
|
w.WriteMsg(req)
|
|
fallthrough
|
|
case MsgIgnore:
|
|
if w.udp != nil && cap(m) == srv.UDPSize {
|
|
srv.udpPool.Put(m[:srv.UDPSize])
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
w.tsigStatus = nil
|
|
if w.tsigSecret != nil {
|
|
if t := req.IsTsig(); t != nil {
|
|
if secret, ok := w.tsigSecret[t.Hdr.Name]; ok {
|
|
w.tsigStatus = TsigVerify(m, secret, "", false)
|
|
} else {
|
|
w.tsigStatus = ErrSecret
|
|
}
|
|
w.tsigTimersOnly = false
|
|
w.tsigRequestMAC = req.Extra[len(req.Extra)-1].(*TSIG).MAC
|
|
}
|
|
}
|
|
|
|
if w.udp != nil && cap(m) == srv.UDPSize {
|
|
srv.udpPool.Put(m[:srv.UDPSize])
|
|
}
|
|
|
|
srv.Handler.ServeDNS(w, req) // Writes back to the client
|
|
}
|
|
|
|
func (srv *Server) readTCP(conn net.Conn, timeout time.Duration) ([]byte, error) {
|
|
// If we race with ShutdownContext, the read deadline may
|
|
// have been set in the distant past to unblock the read
|
|
// below. We must not override it, otherwise we may block
|
|
// ShutdownContext.
|
|
srv.lock.RLock()
|
|
if srv.started {
|
|
conn.SetReadDeadline(time.Now().Add(timeout))
|
|
}
|
|
srv.lock.RUnlock()
|
|
|
|
var length uint16
|
|
if err := binary.Read(conn, binary.BigEndian, &length); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
m := make([]byte, length)
|
|
if _, err := io.ReadFull(conn, m); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return m, nil
|
|
}
|
|
|
|
func (srv *Server) readUDP(conn *net.UDPConn, timeout time.Duration) ([]byte, *SessionUDP, error) {
|
|
srv.lock.RLock()
|
|
if srv.started {
|
|
// See the comment in readTCP above.
|
|
conn.SetReadDeadline(time.Now().Add(timeout))
|
|
}
|
|
srv.lock.RUnlock()
|
|
|
|
m := srv.udpPool.Get().([]byte)
|
|
n, s, err := ReadFromSessionUDP(conn, m)
|
|
if err != nil {
|
|
srv.udpPool.Put(m)
|
|
return nil, nil, err
|
|
}
|
|
m = m[:n]
|
|
return m, s, nil
|
|
}
|
|
|
|
func (srv *Server) readPacketConn(conn net.PacketConn, timeout time.Duration) ([]byte, net.Addr, error) {
|
|
srv.lock.RLock()
|
|
if srv.started {
|
|
// See the comment in readTCP above.
|
|
conn.SetReadDeadline(time.Now().Add(timeout))
|
|
}
|
|
srv.lock.RUnlock()
|
|
|
|
m := srv.udpPool.Get().([]byte)
|
|
n, addr, err := conn.ReadFrom(m)
|
|
if err != nil {
|
|
srv.udpPool.Put(m)
|
|
return nil, nil, err
|
|
}
|
|
m = m[:n]
|
|
return m, addr, nil
|
|
}
|
|
|
|
// WriteMsg implements the ResponseWriter.WriteMsg method.
|
|
func (w *response) WriteMsg(m *Msg) (err error) {
|
|
if w.closed {
|
|
return &Error{err: "WriteMsg called after Close"}
|
|
}
|
|
|
|
var data []byte
|
|
if w.tsigSecret != nil { // if no secrets, dont check for the tsig (which is a longer check)
|
|
if t := m.IsTsig(); t != nil {
|
|
data, w.tsigRequestMAC, err = TsigGenerate(m, w.tsigSecret[t.Hdr.Name], w.tsigRequestMAC, w.tsigTimersOnly)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
_, err = w.writer.Write(data)
|
|
return err
|
|
}
|
|
}
|
|
data, err = m.Pack()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
_, err = w.writer.Write(data)
|
|
return err
|
|
}
|
|
|
|
// Write implements the ResponseWriter.Write method.
|
|
func (w *response) Write(m []byte) (int, error) {
|
|
if w.closed {
|
|
return 0, &Error{err: "Write called after Close"}
|
|
}
|
|
|
|
switch {
|
|
case w.udp != nil:
|
|
if u, ok := w.udp.(*net.UDPConn); ok {
|
|
return WriteToSessionUDP(u, m, w.udpSession)
|
|
}
|
|
return w.udp.WriteTo(m, w.pcSession)
|
|
case w.tcp != nil:
|
|
if len(m) > MaxMsgSize {
|
|
return 0, &Error{err: "message too large"}
|
|
}
|
|
|
|
msg := make([]byte, 2+len(m))
|
|
binary.BigEndian.PutUint16(msg, uint16(len(m)))
|
|
copy(msg[2:], m)
|
|
return w.tcp.Write(msg)
|
|
default:
|
|
panic("dns: internal error: udp and tcp both nil")
|
|
}
|
|
}
|
|
|
|
// LocalAddr implements the ResponseWriter.LocalAddr method.
|
|
func (w *response) LocalAddr() net.Addr {
|
|
switch {
|
|
case w.udp != nil:
|
|
return w.udp.LocalAddr()
|
|
case w.tcp != nil:
|
|
return w.tcp.LocalAddr()
|
|
default:
|
|
panic("dns: internal error: udp and tcp both nil")
|
|
}
|
|
}
|
|
|
|
// RemoteAddr implements the ResponseWriter.RemoteAddr method.
|
|
func (w *response) RemoteAddr() net.Addr {
|
|
switch {
|
|
case w.udpSession != nil:
|
|
return w.udpSession.RemoteAddr()
|
|
case w.pcSession != nil:
|
|
return w.pcSession
|
|
case w.tcp != nil:
|
|
return w.tcp.RemoteAddr()
|
|
default:
|
|
panic("dns: internal error: udpSession, pcSession and tcp are all nil")
|
|
}
|
|
}
|
|
|
|
// TsigStatus implements the ResponseWriter.TsigStatus method.
|
|
func (w *response) TsigStatus() error { return w.tsigStatus }
|
|
|
|
// TsigTimersOnly implements the ResponseWriter.TsigTimersOnly method.
|
|
func (w *response) TsigTimersOnly(b bool) { w.tsigTimersOnly = b }
|
|
|
|
// Hijack implements the ResponseWriter.Hijack method.
|
|
func (w *response) Hijack() { w.hijacked = true }
|
|
|
|
// Close implements the ResponseWriter.Close method
|
|
func (w *response) Close() error {
|
|
if w.closed {
|
|
return &Error{err: "connection already closed"}
|
|
}
|
|
w.closed = true
|
|
|
|
switch {
|
|
case w.udp != nil:
|
|
// Can't close the udp conn, as that is actually the listener.
|
|
return nil
|
|
case w.tcp != nil:
|
|
return w.tcp.Close()
|
|
default:
|
|
panic("dns: internal error: udp and tcp both nil")
|
|
}
|
|
}
|
|
|
|
// ConnectionState() implements the ConnectionStater.ConnectionState() interface.
|
|
func (w *response) ConnectionState() *tls.ConnectionState {
|
|
type tlsConnectionStater interface {
|
|
ConnectionState() tls.ConnectionState
|
|
}
|
|
if v, ok := w.tcp.(tlsConnectionStater); ok {
|
|
t := v.ConnectionState()
|
|
return &t
|
|
}
|
|
return nil
|
|
}
|