io.netty.handler.pcap.PcapHeaders Maven / Gradle / Ivy
/*
* 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;
import java.io.IOException;
import java.io.OutputStream;
final class PcapHeaders {
/**
* Pcap Global Header built from:
*
* - magic_number
* - version_major
* - version_minor
* - thiszone
* - sigfigs
* - snaplen
* - network
*
*/
private static final byte[] GLOBAL_HEADER = {-95, -78, -61, -44, 0, 2, 0, 4, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 0, 0, 0, 1};
private PcapHeaders() {
// Prevent outside initialization
}
/**
* Writes the Pcap Global Header to the provided {@code OutputStream}
*
* @param outputStream OutputStream where Pcap data will be written.
* @throws IOException if there is an error writing to the {@code OutputStream}
*/
static void writeGlobalHeader(OutputStream outputStream) throws IOException {
outputStream.write(GLOBAL_HEADER);
}
/**
* Write Pcap Packet Header
*
* @param byteBuf ByteBuf where we'll write header data
* @param ts_sec timestamp seconds
* @param ts_usec timestamp microseconds
* @param incl_len number of octets of packet saved in file
* @param orig_len actual length of packet
*/
static void writePacketHeader(ByteBuf byteBuf, int ts_sec, int ts_usec, int incl_len, int orig_len) {
byteBuf.writeInt(ts_sec);
byteBuf.writeInt(ts_usec);
byteBuf.writeInt(incl_len);
byteBuf.writeInt(orig_len);
}
}