tcp_segment.cc

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#include "tcp_segment.hh"
 
#include "parser.hh"
#include "util.hh"
 
#include <variant>
 
using namespace std;
 
ParseResult TCPSegment::parse(const Buffer buffer, const uint32_t datagram_layer_checksum) {
    InternetChecksum check(datagram_layer_checksum);
    check.add(buffer);
    if (check.value()) {
        return ParseResult::BadChecksum;
    }
 
    NetParser p{buffer};
    _header.parse(p);
    _payload = p.buffer();
    return p.get_error();
}
 
size_t TCPSegment::length_in_sequence_space() const {
    return payload().str().size() + (header().syn ? 1 : 0) + (header().fin ? 1 : 0);
}
 
BufferList TCPSegment::serialize(const uint32_t datagram_layer_checksum) const {
    TCPHeader header_out = _header;
    header_out.cksum = 0;
 
    // calculate checksum -- taken over entire segment
    InternetChecksum check(datagram_layer_checksum);
    check.add(header_out.serialize());
    check.add(_payload);
    header_out.cksum = check.value();
 
    BufferList ret;
    ret.append(header_out.serialize());
    ret.append(_payload);
 
    return ret;
}