arp.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_ARP_H
#define TINS_ARP_H

#include <tins/macros.h>
#include <tins/pdu.h>
#include <tins/endianness.h>
#include <tins/hw_address.h>
#include <tins/ip_address.h>

namespace Tins {

class NetworkInterface;
class EthernetII;

/**
 * \class ARP
 * \brief Represents an ARP PDU.
 *
 */
class TINS_API ARP : public PDU {
public:
    /**
     * The type of the hardware address.
     */
    typedef HWAddress<6> hwaddress_type;
    
    /**
     * The type of the IP address.
     */
    typedef IPv4Address ipaddress_type;

    /**
     * \brief This PDU's flag.
     */
    static const PDU::PDUType pdu_flag = PDU::ARP;

    /**
     * \brief Enum which indicates the type of ARP packet.
     */
    enum Flags {
        REQUEST = 0x0001,
        REPLY   = 0x0002
    };

    /**
     * \brief Extracts metadata for this protocol based on the buffer provided
     *
     * \param buffer Pointer to a buffer
     * \param total_sz Size of the buffer pointed by buffer
     */
    static metadata extract_metadata(const uint8_t *buffer, uint32_t total_sz);

    /**
     * \brief Constructs an ARP object using the provided addresses.
     * 
     * ARP requests and replies can be constructed easily using
     * ARP::make_arp_request/reply static member functions.
     * 
     * \sa ARP::make_arp_request
     * \sa ARP::make_arp_reply
     * 
     * \param target_ip The target IP address.
     * \param sender_ip The sender IP address.
     * \param target_hw The target hardware address.
     * \param sender_hw The sender hardware address.
     */
    ARP(ipaddress_type target_ip = ipaddress_type(), 
        ipaddress_type sender_ip = ipaddress_type(), 
        const hwaddress_type& target_hw = hwaddress_type(), 
        const hwaddress_type& sender_hw = hwaddress_type());

    /**
     * \brief Constructs an ARP object from a buffer.
     * 
     * If there is not enough size for an ARP header in the buffer,
     * a malformed_packet exception is thrown. 
     * 
     * If the buffer is bigger than the size of the ARP header, 
     * then the extra data is stored in a RawPDU.
     * 
     * \param buffer The buffer from which this PDU will be constructed.
     * \param total_sz The total size of the buffer.
     */
    ARP(const uint8_t* buffer, uint32_t total_sz);

    /* Getters */
    /**
     * \brief Getter for the sender's hardware address.
     *
     * \return The sender hardware address.
     */
    hwaddress_type sender_hw_addr() const {
        return header_.sender_hw_address;
    }

    /**
     * \brief Getter for the sender's IP address.
     *
     * \return The sender IP address.
     */
    ipaddress_type sender_ip_addr() const {
        return ipaddress_type(header_.sender_ip_address);
    }

    /**
     * \brief Getter for the target's hardware address.
     *
     * \return The target hardware address.
     */
    hwaddress_type target_hw_addr() const {
        return header_.target_hw_address;
    }

    /**
     * \brief Getter for the target's IP address.
     *
     * \return The target IP address.
     */
    ipaddress_type target_ip_addr() const {
        return ipaddress_type(header_.target_ip_address);
    }

    /**
     * \brief Getter for the hardware address format field.
     *
     * \return The hardware address format.
     */
    uint16_t hw_addr_format() const {
        return Endian::be_to_host(header_.hw_address_format);
    }

    /**
     * \brief Getter for the protocol address format field.
     *
     * \return The protocol address format.
     */
    uint16_t prot_addr_format() const {
        return Endian::be_to_host(header_.proto_address_format);
    }

    /**
     * \brief Getter for the hardware address length field.
     *
     * \return The hardware address length.
     */
    uint8_t hw_addr_length() const {
        return header_.hw_address_length;
    }

    /**
     * \brief Getter for the protocol address length field.
     *
     * \return The protocol address length.
     */
    uint8_t prot_addr_length() const {
        return header_.proto_address_length;
    }

    /**
     * \brief Getter for the ARP opcode field.
     *
     * \return The ARP opcode.
     */
    uint16_t opcode() const {
        return Endian::be_to_host(header_.opcode);
    }

    /** 
     * \brief Getter for the header size.
     * \return Returns the ARP header size.
     * \sa PDU::header_size
     */
    uint32_t header_size() const;

    /* Setters */

    /**
     * \brief Setter for the sender's hardware address.
     *
     * \param address The new sender hardware address.
     */
    void sender_hw_addr(const hwaddress_type& address);

    /**
     * \brief Setter for the sender's IP address.
     *
     * \param address The new sender IP address.
     */
    void sender_ip_addr(ipaddress_type address);

    /**
     * \brief Setter for the target's hardware address.
     *
     * \param address The new target hardware address.
     */
    void target_hw_addr(const hwaddress_type& address);

    /**
     * \brief Setter for the target's IP address.
     *
     * \param address The new target IP address.
     */
    void target_ip_addr(ipaddress_type address);

    /**
     * \brief Setter for the hardware address format field.
     *
     * \param format The new hardware address format.
     */
    void hw_addr_format(uint16_t format);

    /**
     * \brief Setter for the protocol address format field.
     *
     * \param format The new protocol address format.
     */
    void prot_addr_format(uint16_t format);

    /**
     * \brief Setter for the hardware address length field.
     *
     * \param length The new hardware address length.
     */
    void hw_addr_length(uint8_t length);

    /**
     * \brief Setter for the protocol address length field.
     *
     * \param length The new protocol address length.
     */
    void prot_addr_length(uint8_t length);

    /**
     * \brief Setter for the ARP opcode field.
     *
     * \param code Flag enum value of the ARP opcode to set.
     */
    void opcode(Flags code);

    /**
     * \brief Getter for the PDU's type.
     * \sa PDU::pdu_type
     */
    PDUType pdu_type() const { return pdu_flag; }

    /**
     * \brief Creates an ARP Request within an EthernetII PDU.
     *
     * Creates an ARP Request PDU and embeds it inside an EthernetII
     * PDU.
     *
     * \param target The target's IP address.
     * \param sender The sender's IP address.
     * \param hw_snd The sender's hardware address.
     * \return EthernetII object containing the ARP Request.
     */
    static EthernetII make_arp_request(ipaddress_type target, 
                                       ipaddress_type sender, 
                                       const hwaddress_type& hw_snd = hwaddress_type());

    /**
     * \brief Creates an ARP Reply within an EthernetII PDU.
     *
     * Creates an ARP Reply PDU and embeds it inside an EthernetII 
     * PDU.
     *
     * \param target The target's IP address.
     * \param sender The sender's IP address.
     * \param hw_tgt The target's hardware address.
     * \param hw_snd The sender's hardware address.
     * \return EthernetII object containing the ARP Reply.
     */
    static EthernetII make_arp_reply(ipaddress_type target, 
                                     ipaddress_type sender, 
                                     const hwaddress_type& hw_tgt = hwaddress_type(), 
                                     const hwaddress_type& hw_snd = hwaddress_type());

    /** 
     * \brief Check whether ptr points to a valid response for this PDU.
     *
     * \sa PDU::matches_response
     * \param ptr The pointer to the buffer.
     * \param total_sz The size of the buffer.
     */
    bool matches_response(const uint8_t* ptr, uint32_t total_sz) const;
    
    /**
     * \sa PDU::clone
     */
    ARP* clone() const {
        return new ARP(*this);
    }
private:
    TINS_BEGIN_PACK
    struct arp_header {
        uint16_t hw_address_format;
        uint16_t proto_address_format;
        uint8_t	hw_address_length;
        uint8_t	proto_address_length;
        uint16_t opcode;
        uint8_t sender_hw_address[hwaddress_type::address_size];	
        uint32_t sender_ip_address;	
        uint8_t target_hw_address[hwaddress_type::address_size];	
        uint32_t target_ip_address;
    } TINS_END_PACK;

    void write_serialization(uint8_t* buffer, uint32_t total_sz);

    arp_header header_;
};

} // Tins

#endif // TINS_ARP_H