animation/tcp_abnormal_close.html at main · enhancedformysql/animation · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>TCP Abnormal Connection Closure with CLOSE_WAIT Accumulation</title>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/gsap/3.12.2/gsap.min.js"></script>
    <style>
        body {
            font-family: Arial, sans-serif;
            text-align: center;
            background-color: #222;
            color: #eee;
            padding-top: 50px;
            position: relative;
        }
        .container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            width: 80%;
            margin: 50px auto;
            position: relative;
        }
        .box {
            width: 160px;
            height: 100px;
            line-height: 100px;
            font-size: 16px;
            font-weight: bold;
            border-radius: 10px;
            border: 2px solid #ccc;
            position: relative;
        }
        .established { background-color: #27ae60; }
        .fin_wait_1 { background-color: #f39c12; }
        .fin_wait_2 { background-color: #e67e22; }
        .close_wait { background-color: #d35400; }
        .packet {
            position: absolute;
            width: 130px;
            height: 45px;
            line-height: 45px;
            font-size: 14px;
            font-weight: bold;
            border-radius: 5px;
            background-color: #3498db;
            color: #fff;
            visibility: hidden;
        }
        .state {
            font-size: 14px;
            font-weight: bold;
            margin-top: 5px;
            color: #f1c40f;
        }
        .warning {
            font-size: 18px;
            font-weight: bold;
            color: #e74c3c;
            margin-top: 20px;
        }
        /* Watermark style */
        .watermark {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            font-size: 50px;
            font-weight: bold;
            color: rgba(255, 255, 255, 0.15); /* Light color for watermark */
            pointer-events: none; /* Ensures it's not interactive */
            z-index: 10;
            user-select: none; /* Prevents text selection */
        }
    </style>
</head>
<body>

    <!-- Watermark -->
    <div class="watermark">wangbin579</div>

    <h2>TCP Abnormal Connection Closure with CLOSE_WAIT Accumulation</h2>

    <div class="container">
        <div>
            <div id="clientBox" class="box established">Client</div>
            <div id="clientState" class="state">ESTABLISHED</div>
        </div>
        <div>
            <div id="serverBox" class="box established">Server</div>
            <div id="serverState" class="state">ESTABLISHED</div>
        </div>
    </div>

    <div id="finPacket" class="packet">FIN -></div>
    <div id="ackPacket" class="packet"><- ACK</div>

    <div id="warning" class="warning" style="visibility: hidden;">
        Warning: Server has too many CLOSE_WAIT connections! Resources may be exhausted!
    </div>

    <script>
        function updateState(element, text) {
            document.getElementById(element).innerText = text;
        }

        function startHandshake() {
            let clientBox = document.getElementById("clientBox");
            let serverBox = document.getElementById("serverBox");

            let clientX = clientBox.getBoundingClientRect().x + 80;
            let serverX = serverBox.getBoundingClientRect().x + 0;

            let fin = document.getElementById("finPacket");
            let ack = document.getElementById("ackPacket");
            let warning = document.getElementById("warning");

            // Step 1: Client sends FIN ¡ú Server
            updateState("clientState", "FIN_WAIT_1");
            clientBox.className = "box fin_wait_1";
            gsap.set(fin, { visibility: "visible", x: clientX, y: -50 });
            gsap.to(fin, { x: serverX, duration: 3, onComplete: function() {
                gsap.set(fin, { visibility: "hidden" });

                // Step 2: Server responds with ACK
                updateState("serverState", "CLOSE_WAIT");
                serverBox.className = "box close_wait";
                gsap.set(ack, { visibility: "visible", x: serverX, y: -50 });
                gsap.to(ack, { x: clientX, duration: 3, onComplete: function() {
                    gsap.set(ack, { visibility: "hidden" });

                    // Client moves to FIN_WAIT_2
                    updateState("clientState", "FIN_WAIT_2");
                    clientBox.className = "box fin_wait_2";

                    // Step 3: Server forgets to send FIN
                    // Simulate multiple CLOSE_WAIT connections
                    setTimeout(function() {
                        updateState("serverState", "CLOSE_WAIT (Accumulating...)");
                        warning.style.visibility = "visible";
                    }, 2000); // Delay to show warning
                }});
            }});
        }

        setTimeout(startHandshake, 1000);
    </script>

</body>
</html>