tcp.h

/*
 * Copyright (c) 2017, Matias Fontanini
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following disclaimer
 *   in the documentation and/or other materials provided with the
 *   distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef TINS_TCP_H
#define TINS_TCP_H

#include <vector>
#include <stdint.h>
#include <utility>
#include <tins/pdu.h>
#include <tins/macros.h>
#include <tins/endianness.h>
#include <tins/small_uint.h>
#include <tins/pdu_option.h>
#include <tins/cxxstd.h>

namespace Tins {
namespace Memory {
class OutputMemoryStream;
} // Memory

class TINS_API TCP : public PDU {
public:
    static const PDU::PDUType pdu_flag = PDU::TCP;

    enum Flags {
        FIN = 1,
        SYN = 2,
        RST = 4,
        PSH = 8,
        ACK = 16,
        URG = 32,
        ECE = 64,
        CWR = 128
    };

    enum OptionTypes {
        EOL     = 0,
        NOP     = 1,
        MSS     = 2,
        WSCALE  = 3,
        SACK_OK = 4,
        SACK    = 5,
        TSOPT   = 8,
        ALTCHK  = 14,
        RFC_EXPERIMENT_1 = 253,
        RFC_EXPERIMENT_2 = 254
    };
    
    enum AltChecksums {
        CHK_TCP,
        CHK_8FLETCHER,
        CHK_16FLETCHER
    };
    
    typedef PDUOption<uint8_t, TCP> option;

    typedef std::vector<option> options_type;
    
    typedef std::vector<uint32_t> sack_type;

    static metadata extract_metadata(const uint8_t *buffer, uint32_t total_sz);

    TCP(uint16_t dport = 0, uint16_t sport = 0);

    TCP(const uint8_t* buffer, uint32_t total_sz);

    uint16_t dport() const {
        return Endian::be_to_host(header_.dport);
    }

    uint16_t sport() const {
        return Endian::be_to_host(header_.sport);
    }

    uint32_t seq() const {
        return Endian::be_to_host(header_.seq);
    }

    uint32_t ack_seq() const {
        return Endian::be_to_host(header_.ack_seq);
    }

    uint16_t window() const {
        return Endian::be_to_host(header_.window);
    }

    uint16_t checksum() const {
        return Endian::be_to_host(header_.check);
    }

    uint16_t urg_ptr() const {
        return Endian::be_to_host(header_.urg_ptr);
    }

    small_uint<4> data_offset() const {
        return this->header_.doff;
    }

    const options_type& options() const {
        return options_;
    }

    small_uint<1> get_flag(Flags tcp_flag) const;

    small_uint<12> flags() const;
    
    /* Setters */

    void dport(uint16_t new_dport);

    void sport(uint16_t new_sport);

    void seq(uint32_t new_seq);

    void ack_seq(uint32_t new_ack_seq);

    void window(uint16_t new_window);

    void urg_ptr(uint16_t new_urg_ptr);

    void data_offset(small_uint<4> new_doff);

    // Options

    void mss(uint16_t value);

    uint16_t mss() const;

    void winscale(uint8_t value);
    
    uint8_t winscale() const;

    void sack_permitted();
    
    bool has_sack_permitted() const;
    
    void sack(const sack_type& edges);
    
    sack_type sack() const;

    void timestamp(uint32_t value, uint32_t reply);

    std::pair<uint32_t, uint32_t> timestamp() const;

    void altchecksum(AltChecksums value);
    
    AltChecksums altchecksum() const;

    void set_flag(Flags tcp_flag, small_uint<1> value);
    
    void flags(small_uint<12> value);
    

    void add_option(const option& opt);
    
    #if TINS_IS_CXX11

        void add_option(option &&opt) {
            options_.push_back(std::move(opt));
        }

        template <typename... Args>
        void add_option(Args&&... args) {
            options_.emplace_back(std::forward<Args>(args)...);
        }
    #endif

    bool remove_option(OptionTypes type);

    uint32_t header_size() const;
    
    bool matches_response(const uint8_t* ptr, uint32_t total_sz) const;

    PDUType pdu_type() const {
        return pdu_flag;
    }

    const option* search_option(OptionTypes type) const;
    
    TCP* clone() const {
        return new TCP(*this);
    }
private:
    #if TINS_IS_LITTLE_ENDIAN
        TINS_BEGIN_PACK
        struct flags_type {
            uint8_t fin:1,
                syn:1,
                rst:1,
                psh:1,
                ack:1,
                urg:1,
                ece:1,
                cwr:1;
        } TINS_END_PACK;
    #else
        TINS_BEGIN_PACK
        struct flags_type {
            uint8_t cwr:1,
                ece:1,
                urg:1,
                ack:1,
                psh:1,
                rst:1,
                syn:1,
                fin:1;
        } TINS_END_PACK;
    #endif

    TINS_BEGIN_PACK
    struct tcp_header {
        uint16_t sport;
        uint16_t dport;
        uint32_t seq;
        uint32_t ack_seq;
    #if TINS_IS_LITTLE_ENDIAN
        uint8_t res1:4,
            doff:4;
    #else
        uint8_t doff:4,
            res1:4;
    #endif
        union {
            flags_type flags;
            uint8_t flags_8;
        };
        uint16_t    window;
        uint16_t    check;
        uint16_t    urg_ptr;
    } TINS_END_PACK;

    static const uint16_t DEFAULT_WINDOW;
    
    template <typename T> 
    T generic_search(OptionTypes opt_type) const {
        const option* opt = search_option(opt_type);
        if (!opt) {
            throw option_not_found();
        }
        return opt->to<T>();
    }
    
    void write_serialization(uint8_t* buffer, uint32_t total_sz);
    void checksum(uint16_t new_check);
    uint32_t calculate_options_size() const;
    uint32_t pad_options_size(uint32_t size) const;
    options_type::const_iterator search_option_iterator(OptionTypes type) const;
    options_type::iterator search_option_iterator(OptionTypes type);
    
    void write_option(const option& opt, Memory::OutputMemoryStream& stream);

    options_type options_;
    tcp_header header_;
};

} // Tins

#endif // TINS_TCP_H