add keepalive to socket connections

lib/socketserver/GwSocketHelper.h

@@ -0,0 +1,20 @@
+#pragma once
+#include <lwip/sockets.h>
+
+class GwSocketHelper{
+    public:
+        static bool setKeepAlive(int socket, bool noDelay=true){
+            int val=1;
+            if (noDelay){
+                if (setsockopt(socket, IPPROTO_TCP, TCP_NODELAY, (char *)&val, sizeof(int)) != ESP_OK) return false;
+            }
+            if (setsockopt(socket, SOL_SOCKET, SO_KEEPALIVE, (char *)&val, sizeof(int)) != ESP_OK) return false;
+            val = 10; // seconds of idleness before first keepalive probe
+            if (setsockopt(socket, IPPROTO_TCP, TCP_KEEPIDLE, &val, sizeof(val)) != ESP_OK) return false;
+            val = 5; // interval between first and subsequent keepalives
+            if (setsockopt(socket, IPPROTO_TCP, TCP_KEEPINTVL, &val, sizeof(val)) != ESP_OK) return false;
+            val = 4; // number of lost keepalives before we close the socket
+            if (setsockopt(socket, IPPROTO_TCP, TCP_KEEPCNT, &val, sizeof(val)) != ESP_OK) return false;
+            return true;  
+        }
+};

lib/socketserver/GwSocketServer.cpp

@@ -3,6 +3,7 @@
 #include <lwip/sockets.h>
 #include "GwBuffer.h"
 #include "GwSocketConnection.h"
+#include "GwSocketHelper.h"
 
 GwSocketServer::GwSocketServer(const GwConfigHandler *config, GwLog *logger, int minId)
 {
@@ -62,11 +63,13 @@ int GwSocketServer::available()
     if (client_sock >= 0)
     {
         int val = 1;
-        if (setsockopt(client_sock, SOL_SOCKET, SO_KEEPALIVE, (char *)&val, sizeof(int)) == ESP_OK)
+        if (! GwSocketHelper::setKeepAlive(client_sock,true)){
+            LOG_DEBUG(GwLog::ERROR,"unable to set keepalive, nodelay on socket");
+        }
+        else
         {
-            if (setsockopt(client_sock, IPPROTO_TCP, TCP_NODELAY, (char *)&val, sizeof(int)) == ESP_OK)
+            fcntl(client_sock, F_SETFL, O_NONBLOCK);
-                fcntl(client_sock, F_SETFL, O_NONBLOCK);
+            return client_sock;
-                return client_sock;
         }
         close(client_sock);
     }

lib/socketserver/GwTcpClient.cpp

@@ -1,6 +1,7 @@
 #include "GwTcpClient.h"
 #include <functional>
 #include <ESPmDNS.h>
+#include "GwSocketHelper.h"
 
 class ResolveArgs{
     public:
@@ -72,6 +73,12 @@ void GwTcpClient::startConnection()
         LOG_DEBUG(GwLog::ERROR,"unable to create socket: %d", errno);
         return; 
     }
+    if (! GwSocketHelper::setKeepAlive(sockfd,true)){
+        error="unable to set keepalive, nodelay on socket";
+        LOG_DEBUG(GwLog::ERROR,"%s",error.c_str());
+        close(sockfd);
+        return;
+    }
     fcntl( sockfd, F_SETFL, fcntl( sockfd, F_GETFL, 0 ) | O_NONBLOCK );
     int res = lwip_connect_r(sockfd, (struct sockaddr*)&serveraddr, sizeof(serveraddr));
     if (res < 0 ) {