ostinato/common/packet.h
2023-05-26 11:31:52 +05:30

113 lines
2.6 KiB
C++

/*
Copyright (C) 2023 Srivats P.
This file is part of "Ostinato"
This is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>
*/
#ifndef _PACKET_H
#define _PACKET_H
#include <QSet>
#include <QtGlobal>
namespace Packet {
class Parser {
public:
Parser(const uchar *data, int length)
: pktData_(data), pktLen_(length) {}
quint8 field8(int offset) {
if (offset >= pktLen_) {
ok_ = false;
return 0;
}
ok_ = true;
return pktData_[offset];
}
quint16 field16(int offset) {
if (offset + 1 >= pktLen_) {
ok_ = false;
return 0;
}
ok_ = true;
return pktData_[offset] << 8
| pktData_[offset+1];
}
quint32 field32(int offset) {
if (offset + 3 >= pktLen_) {
ok_ = false;
return 0;
}
ok_ = true;
return pktData_[offset] << 24
| pktData_[offset+1] << 16
| pktData_[offset+2] << 8
| pktData_[offset+3];
}
bool ok() {
return ok_;
}
private:
const uchar *pktData_;
int pktLen_;
bool ok_{false};
};
quint16 l4ChecksumOffset(const uchar *pktData, int pktLen);
//
// Constants
//
// Ethernet
const quint16 kEthTypeOffset = 12;
const quint16 kEthTypeSize = 2;
const quint16 kIp4EthType = 0x0800;
const quint16 kIp6EthType = 0x86dd;
const quint16 kMplsEthType = 0x8847;
const QSet<quint16> kVlanEthTypes = {0x8100, 0x9100, 0x88a8};
// VLAN
const quint16 kVlanTagSize = 4;
// MPLS
const quint16 kMplsTagSize = 4;
// IPv4
const quint16 kIp4ProtocolOffset = 9;
// IPv6
const quint16 kIp6HeaderSize = 40;
const quint16 kIp6NextHeaderOffset = 6;
// IPv6 Extension Header
const quint16 kIp6ExtNextHeaderOffset = 0;
const quint16 kIp6ExtLengthOffset = 1;
// IPv4/IPv6 Proto/NextHeader values
const quint8 kIpProtoTcp = 6;
const quint8 kIpProtoUdp = 17;
const QSet<quint8> kIp6ExtensionHeaders = {0, 60, 43, 44, 51, 50, 60, 135}; // FIXME: use names
// TCP
const quint16 kTcpChecksumOffset = 16;
// UDP
const quint16 kUdpChecksumOffset = 6;
};
#endif