Disable Nagle in iprop master and slave

configure.ac

@@ -355,6 +355,7 @@ AC_CHECK_HEADERS([\
 	maillock.h				\
 	netgroup.h				\
 	netinet/in6_machtypes.h			\
+	netinet/tcp.h				\
 	pthread.h				\
 	pty.h					\
 	sac.h					\

include/config.h.w32

@@ -653,6 +653,9 @@ static const char *const rcsid[] = { (const char *)rcsid, "@(#)" msg }
 /* Define to 1 if you have the <netinet/in.h> header file. */
 /* #define HAVE_NETINET_IN_H 1 */
 
+/* Define to 1 if you have the <netinet/tcp.h> header file. */
+/* #define HAVE_NETINET_TCP_H 1 */
+
 /* Define to 1 if you have the <netinet/in_systm.h> header file. */
 /* #define HAVE_NETINET_IN_SYSTM_H 1 */
 

lib/kadm5/ipropd_master.c

@@ -319,6 +319,20 @@ add_slave (krb5_context context, krb5_keytab keytab, slave **root,
      * own krb5_recvauth().
      */
     socket_set_nonblocking(s->fd, 1);
+
+    /*
+     * We write message lengths separately from the payload, and may do
+     * back-to-back small writes when flushing pending input and then a new
+     * update.  Avoid Nagle delays.
+     */
+#if defined(IPPROTO_TCP) && defined(TCP_NODELAY)
+    {
+        int nodelay = 1;
+        (void) setsockopt(s->fd, IPPROTO_TCP, TCP_NODELAY,
+                          (void *)&nodelay, sizeof(nodelay));
+    }
+#endif
+
     krb5_free_principal (context, server);
     if (ret) {
 	krb5_warn (context, ret, "krb5_recvauth");

lib/kadm5/ipropd_slave.c

@@ -99,6 +99,15 @@ connect_to_master (krb5_context context, const char *master,
     if (setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, &one, sizeof(one)) < 0)
         krb5_warn(context, errno, "setsockopt(SO_KEEPALIVE) failed");
 
+    /*
+     * We write message lengths separately from the payload, avoid Nagle
+     * delays.
+     */
+#if defined(IPPROTO_TCP) && defined(TCP_NODELAY)
+    (void) setsockopt(s, IPPROTO_TCP, TCP_NODELAY,
+                      (void *)&one, sizeof(one));
+#endif
+
     return s;
 }
 

lib/kadm5/kadm5_locl.h

@@ -67,6 +67,12 @@
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
 #endif
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+#ifdef HAVE_NETINET_TCP_H
+#include <netinet/tcp.h>
+#endif
 #ifdef HAVE_SYS_UN_H
 #include <sys/un.h>
 #endif