Multi-client servers + bring back stdinserver support

daemon/serve/serve_tcp.go

@@ -3,19 +3,89 @@ package serve
 import (
 	"github.com/zrepl/zrepl/config"
 	"net"
+	"github.com/pkg/errors"
+	"context"
 )
 
 type TCPListenerFactory struct {
-	Address string
+	address *net.TCPAddr
+	clientMap *ipMap
+}
+
+type ipMapEntry struct {
+	ip net.IP
+	ident string
+}
+
+type ipMap struct {
+	entries []ipMapEntry
+}
+
+func ipMapFromConfig(clients map[string]string) (*ipMap, error) {
+	entries := make([]ipMapEntry, 0, len(clients))
+	for clientIPString, clientIdent := range clients {
+		clientIP := net.ParseIP(clientIPString)
+		if clientIP == nil {
+			return nil, errors.Errorf("cannot parse client IP %q", clientIPString)
+		}
+		if err := ValidateClientIdentity(clientIdent); err != nil {
+			return nil, errors.Wrapf(err,"invalid client identity for IP %q", clientIPString)
+		}
+		entries = append(entries, ipMapEntry{clientIP, clientIdent})
+	}
+	return &ipMap{entries: entries}, nil
+}
+
+func (m *ipMap) Get(ip net.IP) (string, error) {
+	for _, e := range m.entries {
+		if e.ip.Equal(ip) {
+			return e.ident, nil
+		}
+	}
+	return "", errors.Errorf("no identity mapping for client IP %s", ip)
 }
 
 func TCPListenerFactoryFromConfig(c *config.Global, in *config.TCPServe) (*TCPListenerFactory, error) {
+	addr, err := net.ResolveTCPAddr("tcp", in.Listen)
+	if err != nil {
+		return nil, errors.Wrap(err, "cannot parse listen address")
+	}
+	clientMap, err := ipMapFromConfig(in.Clients)
+	if err != nil {
+		return nil, errors.Wrap(err, "cannot parse client IP map")
+	}
 	lf := &TCPListenerFactory{
-		Address: in.Listen,
+		address: addr,
+		clientMap: clientMap,
 	}
 	return lf, nil
 }
 
-func (f *TCPListenerFactory) Listen() (net.Listener, error) {
-	return net.Listen("tcp", f.Address)
+func (f *TCPListenerFactory) Listen() (AuthenticatedListener, error) {
+	l, err := net.ListenTCP("tcp", f.address)
+	if err != nil {
+		return nil, err
+	}
+	return &TCPAuthListener{l, f.clientMap}, nil
 }
+
+type TCPAuthListener struct {
+	*net.TCPListener
+	clientMap *ipMap
+}
+
+func (f *TCPAuthListener) Accept(ctx context.Context) (AuthenticatedConn, error) {
+	nc, err := f.TCPListener.Accept()
+	if err != nil {
+		return nil, err
+	}
+	clientIP := nc.RemoteAddr().(*net.TCPAddr).IP
+	clientIdent, err := f.clientMap.Get(clientIP)
+	if err != nil {
+		getLogger(ctx).WithField("ip", clientIP).Error("client IP not in client map")
+		nc.Close()
+		return nil, err
+	}
+	return authConn{nc, clientIdent}, nil
+}
+