libtins/include/tins/internals.h

/*
 * Copyright (c) 2014, 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_INTERNALS_H
#define TINS_INTERNALS_H

#if TINS_IS_CXX11
#include <type_traits>
#endif

#include <sstream>
#include <string>
#include <stdint.h>
#include "constants.h"
#include "pdu.h"
#include "hw_address.h"

/**
 * \cond
 */
namespace Tins {
class IPv4Address;
class IPv6Address;

namespace Internals {
template<size_t n>
class byte_array {
public:
    typedef uint8_t* iterator;
    typedef const uint8_t* const_iterator;

    byte_array() {
        std::fill(begin(), end(), 0);
    }

    template<typename InputIterator>
    byte_array(InputIterator start, InputIterator last) {
        std::copy(start, last, data);
    }

    template<typename InputIterator>
    byte_array(InputIterator start) {
        std::copy(start, n, data);
    }

    uint8_t &operator[](size_t i) {
        return data[i];
    }

    uint8_t operator[](size_t i) const{
        return data[i];
    }

    iterator begin() {
        return data;
    }

    iterator end() {
        return data + n;
    }

    const_iterator begin() const {
        return data;
    }

    const_iterator end() const {
        return data + n;
    }

    size_t size() const {
        return n;
    }
private:
    uint8_t data[n];
};

void skip_line(std::istream &input);
bool from_hex(const std::string &str, uint32_t &result);

template<bool, typename T = void>
struct enable_if {
    typedef T type;
};

template<typename T>
struct enable_if<false, T> {

};

PDU *pdu_from_flag(Constants::Ethernet::e flag, const uint8_t *buffer,
  uint32_t size, bool rawpdu_on_no_match = true);
PDU *pdu_from_flag(Constants::IP::e flag, const uint8_t *buffer,
  uint32_t size, bool rawpdu_on_no_match = true);
PDU *pdu_from_dlt_flag(int flag, const uint8_t *buffer,
  uint32_t size, bool rawpdu_on_no_match = true);
PDU *pdu_from_flag(PDU::PDUType type, const uint8_t *buffer, uint32_t size);

Constants::Ethernet::e pdu_flag_to_ether_type(PDU::PDUType flag);
Constants::IP::e pdu_flag_to_ip_type(PDU::PDUType flag);

template<typename T>
bool increment_buffer(T &addr) {
    typename T::iterator it = addr.end() - 1;
    while(it >= addr.begin() && *it == 0xff) {
        *it = 0;
        --it;
    }
    // reached end
    if(it < addr.begin())
        return true;
    (*it)++;
    return false;
}

template<typename T>
bool decrement_buffer(T &addr) {
    typename T::iterator it = addr.end() - 1;
    while(it >= addr.begin() && *it == 0) {
        *it = 0xff;
        --it;
    }
    // reached end
    if(it < addr.begin())
        return true;
    (*it)--;
    return false;
}

bool increment(IPv4Address &addr);
bool increment(IPv6Address &addr);
bool decrement(IPv4Address &addr);
bool decrement(IPv6Address &addr);
template<size_t n>
bool increment(HWAddress<n> &addr) {
    return increment_buffer(addr);
}
template<size_t n>
bool decrement(HWAddress<n> &addr) {
    return decrement_buffer(addr);
}

IPv4Address last_address_from_mask(IPv4Address addr, IPv4Address mask);
IPv6Address last_address_from_mask(IPv6Address addr, const IPv6Address &mask);
template<size_t n>
HWAddress<n> last_address_from_mask(HWAddress<n> addr, const HWAddress<n> &mask) {
    typename HWAddress<n>::iterator addr_iter = addr.begin();
    for(typename HWAddress<n>::const_iterator it = mask.begin(); it != mask.end(); ++it, ++addr_iter) {
        *addr_iter = *addr_iter | ~*it;
    }
    return addr;
}

inline bool is_dot3(const uint8_t *ptr, size_t sz) {
    return (sz >= 13 && ptr[12] < 8);
}

template<typename T>
struct is_unsigned_integral {
    static const bool value = false;
};

template<>
struct is_unsigned_integral<uint8_t> {
    static const bool value = true;
};

template<>
struct is_unsigned_integral<uint16_t> {
    static const bool value = true;
};

template<>
struct is_unsigned_integral<uint32_t> {
    static const bool value = true;
};

template<>
struct is_unsigned_integral<uint64_t> {
    static const bool value = true;
};

#if TINS_IS_CXX11

// Part of C++14 standard library
template<bool B, class T = void>
using enable_if_t = typename std::enable_if<B,T>::type;

// Template metaprogramming trait to determine if a functor can accept another parameter as an argument
template <class T, class P, class=void>
struct accepts_type : std::false_type { };

template <class T, class P>
struct accepts_type<T, P, enable_if_t<
  std::is_same<  decltype(  std::declval<T>()(std::declval<P>())  ), bool>::value
>> : std::true_type { };

// use enable_if to invoke the Packet& version of the sniff_loop handler if possible - otherwise fail to old behavior
template <class Functor, class Packet>
bool invoke_loop_cb(Functor& f, Packet& p, typename std::enable_if<accepts_type<Functor, Packet>::value, bool>::type* = 0) {
  return f(p);
}

template <class Functor, class Packet>
bool invoke_loop_cb(Functor& f, Packet& p, typename std::enable_if<!accepts_type<Functor, Packet>::value, bool>::type* = 0) {
  return f(*p.pdu());
}
#endif

} // namespace Internals
} // namespace Tins
/**
 * \endcond
 */

#endif