From cc4a3ed9c19bae34952904869fde2b0755f29266 Mon Sep 17 00:00:00 2001
From: Guido Longoni <guido.longoni@briq.it>
Date: Wed, 6 May 2026 12:58:12 +0200
Subject: [PATCH] Aggiungi override probe TCP keepalive

---
 .gitignore                                  |  1 +
 native/tcp_keepalive/binding.gyp            |  8 ++++
 native/tcp_keepalive/tcp_keepalive_native.c | 49 +++++++++++++++++++++
 package-lock.json                           |  3 +-
 package.json                                |  3 ++
 red/tcp/tcp-keepalive.js                    | 41 +++++++++++++++++
 red/tcp/tcp.html                            |  6 +++
 red/tcp/tcp.js                              | 14 +++++-
 scripts/build-tcp-keepalive.js              | 32 ++++++++++++++
 9 files changed, 154 insertions(+), 3 deletions(-)
 create mode 100644 native/tcp_keepalive/binding.gyp
 create mode 100644 native/tcp_keepalive/tcp_keepalive_native.c
 create mode 100644 red/tcp/tcp-keepalive.js
 create mode 100644 scripts/build-tcp-keepalive.js

diff --git a/.gitignore b/.gitignore
index c2658d7..32619a0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 node_modules/
+native/tcp_keepalive/build/
diff --git a/native/tcp_keepalive/binding.gyp b/native/tcp_keepalive/binding.gyp
new file mode 100644
index 0000000..7aff3b6
--- /dev/null
+++ b/native/tcp_keepalive/binding.gyp
@@ -0,0 +1,8 @@
+{
+  "targets": [
+    {
+      "target_name": "tcp_keepalive_native",
+      "sources": [ "tcp_keepalive_native.c" ]
+    }
+  ]
+}
diff --git a/native/tcp_keepalive/tcp_keepalive_native.c b/native/tcp_keepalive/tcp_keepalive_native.c
new file mode 100644
index 0000000..3fd8f0f
--- /dev/null
+++ b/native/tcp_keepalive/tcp_keepalive_native.c
@@ -0,0 +1,49 @@
+#include <node_api.h>
+#include <stdbool.h>
+
+#ifdef __linux__
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <sys/socket.h>
+#endif
+
+static napi_value make_boolean(napi_env env, bool value) {
+    napi_value result;
+    napi_get_boolean(env, value, &result);
+    return result;
+}
+
+static napi_value set_keepalive_probes(napi_env env, napi_callback_info info) {
+    size_t argc = 2;
+    napi_value args[2];
+    int32_t fd = -1;
+    int32_t probes = 0;
+
+    napi_get_cb_info(env, info, &argc, args, NULL, NULL);
+    if (argc < 2) {
+        return make_boolean(env, false);
+    }
+
+    if (napi_get_value_int32(env, args[0], &fd) != napi_ok ||
+        napi_get_value_int32(env, args[1], &probes) != napi_ok ||
+        fd < 0 || probes <= 0) {
+        return make_boolean(env, false);
+    }
+
+#ifdef __linux__
+    return make_boolean(env, setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &probes, sizeof(probes)) == 0);
+#else
+    return make_boolean(env, false);
+#endif
+}
+
+static napi_value init(napi_env env, napi_value exports) {
+    napi_value fn;
+
+    napi_create_function(env, "setKeepAliveProbes", NAPI_AUTO_LENGTH, set_keepalive_probes, NULL, &fn);
+    napi_set_named_property(env, exports, "setKeepAliveProbes", fn);
+
+    return exports;
+}
+
+NAPI_MODULE(NODE_GYP_MODULE_NAME, init)
diff --git a/package-lock.json b/package-lock.json
index 6f7f1a8..bbd1b89 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -6,7 +6,8 @@
     "packages": {
         "": {
             "name": "red-briq-nodes",
-            "version": "0.2.5",
+            "version": "0.2.6",
+            "hasInstallScript": true,
             "license": "Apache-2.0",
             "dependencies": {
                 "denque": "^1.4.1",
diff --git a/package.json b/package.json
index e001b19..53d7d1d 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,9 @@
     "name": "red-briq-nodes",
     "version": "0.2.6",
     "description": "Various forked and original nodes",
+    "scripts": {
+        "install": "node scripts/build-tcp-keepalive.js"
+    },
     "dependencies": {
         "denque": "^1.4.1",
         "simple-xmpp": "^1.3.1",
diff --git a/red/tcp/tcp-keepalive.js b/red/tcp/tcp-keepalive.js
new file mode 100644
index 0000000..9b45ab5
--- /dev/null
+++ b/red/tcp/tcp-keepalive.js
@@ -0,0 +1,41 @@
+"use strict";
+
+let native = null;
+
+try {
+    native = require("../../native/tcp_keepalive/build/Release/tcp_keepalive_native");
+} catch (err) {
+    native = null;
+}
+
+function parseKeepAliveProbes(value) {
+    if (value === undefined || value === null || value === "") {
+        return 0;
+    }
+
+    value = Number(value);
+    if (!Number.isFinite(value) || value < 0) {
+        return 0;
+    }
+
+    return Math.floor(value);
+}
+
+function setKeepAliveProbes(socket, probes) {
+    if (!native || probes <= 0 || !socket || !socket._handle) {
+        return false;
+    }
+
+    const fd = socket._handle.fd;
+    if (!Number.isInteger(fd) || fd < 0) {
+        return false;
+    }
+
+    return native.setKeepAliveProbes(fd, probes) === true;
+}
+
+module.exports = {
+    available: !!native,
+    parseKeepAliveProbes,
+    setKeepAliveProbes
+};
diff --git a/red/tcp/tcp.html b/red/tcp/tcp.html
index 0e03994..28418a2 100644
--- a/red/tcp/tcp.html
+++ b/red/tcp/tcp.html
@@ -44,6 +44,10 @@
         <label><i class="fa fa-clock-o"></i> <span>Keepalive</span></label>
         <input type="text" id="node-input-keepalive" style="text-align:end; width:200px !important">
     </div>
+    <div class="form-row">
+        <label><i class="fa fa-times-circle"></i> <span>Missed keepalives</span></label>
+        <input type="text" id="node-input-keepaliveProbes" style="text-align:end; width:120px !important">
+    </div>
 
     <div id="node-row-newline" class="form-row hidden" style="padding-left:110px;">
         <span data-i18n="tcpin.label.delimited"></span> <input type="text" id="node-input-newline" style="width:110px;">
@@ -72,6 +76,7 @@
             datatype: { value: "buffer" },
             newline: { value: "" },
             keepalive: { value: "120000" },
+            keepaliveProbes: { value: "0" },
             topic: { value: "" },
             base64: {/*deprecated*/ value: false, required: true }
         },
@@ -109,6 +114,7 @@
             $("#node-input-datatype").change(updateOptions);
             $("#node-input-datamode").change(updateOptions);
             $("#node-input-keepalive").spinner({ min: 1 });
+            $("#node-input-keepaliveProbes").spinner({ min: 0 });
         }
     });
 </script>
diff --git a/red/tcp/tcp.js b/red/tcp/tcp.js
index 4d48c69..40df64c 100644
--- a/red/tcp/tcp.js
+++ b/red/tcp/tcp.js
@@ -19,6 +19,7 @@ module.exports = function(RED) {
     var reconnectTime = RED.settings.socketReconnectTime||10000;
     const msgQueueSize = RED.settings.tcpMsgQueueSize || 1000;
     const Denque = require('denque');
+    const tcpKeepAlive = require('./tcp-keepalive');
     var net = require('net');
 
     var connectionPool = {};
@@ -45,6 +46,14 @@ module.exports = function(RED) {
      */
     const dequeue = queue => queue.shift();
 
+    function setKeepAlive(socket, delay, probes, node) {
+        socket.setKeepAlive(true, delay);
+        if (probes > 0 && !tcpKeepAlive.setKeepAliveProbes(socket, probes) && !node.keepaliveProbesWarned) {
+            node.keepaliveProbesWarned = true;
+            node.warn("TCP keepalive probe count override is not available on this platform/runtime");
+        }
+    }
+
     function TcpIn(n) {
         RED.nodes.createNode(this,n);
         this.host = n.host;
@@ -55,6 +64,7 @@ module.exports = function(RED) {
         this.newline = (n.newline||"").replace("\\n","\n").replace("\\r","\r");
         this.base64 = n.base64;
         this.keepalive = parseInt(n.keepalive) || 120000;
+        this.keepaliveProbes = tcpKeepAlive.parseKeepAliveProbes(n.keepaliveProbes);
         this.server = (typeof n.server == 'boolean')?n.server:(n.server == "server");
         this.closing = false;
         this.connected = false;
@@ -76,7 +86,7 @@ module.exports = function(RED) {
                     node.log(RED._("tcpin.status.connected",{host:node.host,port:node.port}));
                     node.status({fill:"green",shape:"dot",text:"common.status.connected"});
                 });
-                client.setKeepAlive(true, node.keepalive);
+                setKeepAlive(client, node.keepalive, node.keepaliveProbes, node);
                 connectionPool[id] = client;
 
                 client.on('data', function (data) {
@@ -151,7 +161,7 @@ module.exports = function(RED) {
         }
         else {
             var server = net.createServer(function (socket) {
-                socket.setKeepAlive(true, node.keepalive);
+                setKeepAlive(socket, node.keepalive, node.keepaliveProbes, node);
                 var id = (1+Math.random()*4294967295).toString(16);
                 var fromi;
                 var fromp;
diff --git a/scripts/build-tcp-keepalive.js b/scripts/build-tcp-keepalive.js
new file mode 100644
index 0000000..a0141eb
--- /dev/null
+++ b/scripts/build-tcp-keepalive.js
@@ -0,0 +1,32 @@
+const { spawnSync } = require("child_process");
+const path = require("path");
+
+if (process.platform !== "linux") {
+    process.exit(0);
+}
+
+const nativeDir = path.join(__dirname, "..", "native", "tcp_keepalive");
+
+function runNodeGyp(command, args) {
+    const result = spawnSync(command, args, {
+        cwd: nativeDir,
+        stdio: "inherit"
+    });
+    return result.error ? false : result.status === 0;
+}
+
+let built = false;
+
+try {
+    const nodeGyp = require.resolve("node-gyp/bin/node-gyp.js");
+    built = runNodeGyp(process.execPath, [nodeGyp, "rebuild"]);
+} catch (err) {
+    built = runNodeGyp("node-gyp", ["rebuild"]);
+    if (!built) {
+        built = runNodeGyp("npx", ["node-gyp", "rebuild"]);
+    }
+}
+
+if (!built) {
+    console.warn("tcp keepalive native helper was not built; TCP_KEEPCNT override will be disabled");
+}