From 0f84236f4a95534adf5e0f2d76c1cc47334b6900 Mon Sep 17 00:00:00 2001
From: Frank Morgner <frankmorgner@gmail.com>
Date: Sat, 28 Feb 2026 01:36:47 +0100
Subject: [PATCH] vpcd: add TCP_NODELAY socket option

Idea from @jetfire13

closes https://github.com/frankmorgner/vsmartcard/pull/323

(cherry picked from commit 92d918e56d25c7c29dabbcac030a30655aeaa3a1)
---
 virtualsmartcard/src/vpcd/vpcd.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/virtualsmartcard/src/vpcd/vpcd.c b/virtualsmartcard/src/vpcd/vpcd.c
index cb5b6f6..371daa3 100644
--- a/virtualsmartcard/src/vpcd/vpcd.c
+++ b/virtualsmartcard/src/vpcd/vpcd.c
@@ -39,6 +39,7 @@ typedef WORD uint16_t;
 #include <arpa/inet.h>
 #include <netdb.h>
 #include <netinet/in.h>
+#include <netinet/tcp.h> /* for TCP_NODELAY */
 #include <poll.h>
 #include <stdint.h>
 #include <sys/socket.h>
@@ -47,6 +48,7 @@ typedef WORD uint16_t;
 #define INVALID_SOCKET -1
 #endif
 
+
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -110,6 +112,10 @@ static SOCKET opensock(unsigned short port)
     if (setsockopt(sock, SOL_SOCKET, SO_NOSIGPIPE, (void *) &yes, sizeof yes) != 0)
         goto err;
 #endif
+#ifdef TCP_NODELAY
+    if(setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void *) &yes, sizeof yes) != 0)
+        goto err;
+#endif
 
     memset(&server_sockaddr, 0, sizeof server_sockaddr);
     server_sockaddr.sin_family      = PF_INET;