Method sendIP

src/network.js:495–518

(payload, protocol, srcIP, dstIP)

    }

    sendIP(payload, protocol, srcIP, dstIP) {
        const header = Buffer.alloc(20);
        header[0] = 0x45; // v4, 5 words
        header[1] = 0; // TOS
        header.writeUInt16BE(20 + payload.length, 2);
        header.writeUInt16BE(0, 4); // ID
        header.writeUInt16BE(0, 6); // Flags/Offset
        header[8] = 64; // TTL
        header[9] = protocol;
        srcIP.copy(header, 12);
        dstIP.copy(header, 16);
        
        // IP Checksum
        header.writeUInt16BE(this.calculateChecksum(header), 10);
        
        const packet = Buffer.concat([header, payload]);
        
        // Check if destination is broadcast
        if (dstIP[0] === 255 && dstIP[1] === 255 && dstIP[2] === 255 && dstIP[3] === 255) {
            this.sendBroadcast(packet, ETH_P_IP);
        } else {
            this.send(packet, ETH_P_IP);
        }
    }
    
    handleTCP(segment, srcIP, dstIP, fullIPPacket) {
        const srcPort = segment.readUInt16BE(0);