diff --git a/src/anet.c b/src/anet.c
index f36575bd4bffd5a0927302464f0064d772233033..d5e1c01a01964378000db20733a00bb90a5b9622 100644
--- a/src/anet.c
+++ b/src/anet.c
@@ -57,24 +57,37 @@ static void anetSetError(char *err, const char *fmt, ...)
     va_end(ap);
 }
 
-int anetNonBlock(char *err, int fd)
-{
+int anetSetBlock(char *err, int fd, int non_block) {
     int flags;
 
-    /* Set the socket non-blocking.
+    /* Set the socket blocking (if non_block is zero) or non-blocking.
      * Note that fcntl(2) for F_GETFL and F_SETFL can't be
      * interrupted by a signal. */
     if ((flags = fcntl(fd, F_GETFL)) == -1) {
         anetSetError(err, "fcntl(F_GETFL): %s", strerror(errno));
         return ANET_ERR;
     }
-    if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
+
+    if (non_block)
+        flags |= O_NONBLOCK;
+    else
+        flags &= ~O_NONBLOCK;
+
+    if (fcntl(fd, F_SETFL, flags) == -1) {
         anetSetError(err, "fcntl(F_SETFL,O_NONBLOCK): %s", strerror(errno));
         return ANET_ERR;
     }
     return ANET_OK;
 }
 
+int anetNonBlock(char *err, int fd) {
+    return anetSetBlock(err,fd,1);
+}
+
+int anetBlock(char *err, int fd) {
+    return anetSetBlock(err,fd,0);
+}
+
 /* Set TCP keep alive option to detect dead peers. The interval option
  * is only used for Linux as we are using Linux-specific APIs to set
  * the probe send time, interval, and count. */
diff --git a/src/anet.h b/src/anet.h
index c4248b9dfb6bcc3b130f576799dcbc630e5a1eb2..3c7296c8d14db908a95fa72e967a0d90e6db1657 100644
--- a/src/anet.h
+++ b/src/anet.h
@@ -61,6 +61,7 @@ int anetTcpAccept(char *err, int serversock, char *ip, size_t ip_len, int *port)
 int anetUnixAccept(char *err, int serversock);
 int anetWrite(int fd, char *buf, int count);
 int anetNonBlock(char *err, int fd);
+int anetBlock(char *err, int fd);
 int anetEnableTcpNoDelay(char *err, int fd);
 int anetDisableTcpNoDelay(char *err, int fd);
 int anetTcpKeepAlive(char *err, int fd);