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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2020 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 * https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.handler.pcap;

import io.netty.buffer.ByteBuf;

final class TCPPacket {

    /**
     * Data Offset + Reserved Bits.
     */
    private static final short OFFSET = 0x5000;

    private TCPPacket() {
        // Prevent outside initialization
    }

    /**
     * Write TCP Packet
     *
     * @param byteBuf ByteBuf where Packet data will be set
     * @param payload Payload of this Packet
     * @param srcPort Source Port
     * @param dstPort Destination Port
     */
    static void writePacket(ByteBuf byteBuf, ByteBuf payload, int segmentNumber, int ackNumber, int srcPort,
                            int dstPort, TCPFlag... tcpFlags) {

        byteBuf.writeShort(srcPort);     // Source Port
        byteBuf.writeShort(dstPort);     // Destination Port
        byteBuf.writeInt(segmentNumber); // Segment Number
        byteBuf.writeInt(ackNumber);     // Acknowledgment Number
        byteBuf.writeShort(OFFSET | TCPFlag.getFlag(tcpFlags)); // Flags
        byteBuf.writeShort(65535);       // Window Size
        byteBuf.writeShort(0x0001);      // Checksum
        byteBuf.writeShort(0);           // Urgent Pointer

        if (payload != null) {
            byteBuf.writeBytes(payload); //  Payload of Data
        }
    }

    enum TCPFlag {
        FIN(1),
        SYN(1 << 1),
        RST(1 << 2),
        PSH(1 << 3),
        ACK(1 << 4),
        URG(1 << 5),
        ECE(1 << 6),
        CWR(1 << 7);

        private final int value;

        TCPFlag(int value) {
            this.value = value;
        }

        static int getFlag(TCPFlag... tcpFlags) {
            int flags = 0;

            for (TCPFlag tcpFlag : tcpFlags) {
                flags |= tcpFlag.value;
            }

            return  flags;
        }
    }
}