
/***************************************************************************
 * IPv4Header.h -- The IPv4Header Class represents an IPv4 datagram. It    *
 * contains methods to set any header field. In general, these methods do  *
 * error checkings and byte order conversion.                              *
 *                                                                         *
 ***********************IMPORTANT NMAP LICENSE TERMS************************
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 *                                                                         *
 ***************************************************************************/
#ifndef IPV4HEADER_H
#define IPV4HEADER_H 1

#include "NetworkLayerElement.h"

#define DEFAULT_IP_TTL 64          /* Default IP Time to Live        */
#define IP_RF 0x8000               /* Reserved fragment flag         */
#define IP_DF 0x4000               /* Dont fragment flag             */
#define IP_MF 0x2000               /* More fragments flag            */
#define IP_OFFMASK 0x1fff          /* Mask for fragmenting bits      */
#define IP_HEADER_LEN 20           /* Length of the standard header  */
#define MAX_IP_OPTIONS_LEN 40      /* Max Length for IP Options      */
        
class IPv4Header : public NetworkLayerElement {

    private:

        struct nping_ipv4_hdr {
        #if WORDS_BIGENDIAN
            u8 ip_v:4;                     /* Version                        */
            u8 ip_hl:4;                    /* Header length                  */
        #else
            u8 ip_hl:4;                    /* Header length                  */
            u8 ip_v:4;                     /* Version                        */
        #endif
            u8 ip_tos;                     /* Type of service                */
            u16 ip_len;                    /* Total length                   */
            u16 ip_id;                     /* Identification                 */
            u16 ip_off;                    /* Fragment offset field          */
            u8 ip_ttl;                     /* Time to live                   */
            u8 ip_p;                       /* Protocol                       */
            u16 ip_sum;                    /* Checksum                       */
            struct in_addr ip_src;         /* Source IP address              */
            struct in_addr ip_dst;         /* Destination IP address         */
            u8 options[MAX_IP_OPTIONS_LEN];  /* IP Options                   */
        }__attribute__((__packed__));

        typedef struct nping_ipv4_hdr nping_ipv4_hdr_t;

        nping_ipv4_hdr_t h;

        int ipoptlen; /**< Length of IP options */

    public:

    /* Misc */
    IPv4Header();
    ~IPv4Header();
    void reset();
    void zero();
    u8 *getBufferPointer();
    int storeRecvData(const u8 *buf, size_t len);
    int validate();

    /* IP version */
    int setVersion();
    u8 getVersion();

    /* Header Length */
    int setHeaderLength();
    int setHeaderLength(u8 l);
    u8 getHeaderLength();

    /* Type of Service */
    int setTOS(u8 v);
    u8 getTOS();

    /* Total lenght of the datagram */
    int setTotalLength();
    int setTotalLength(u16 l);
    u16 getTotalLength();

    /* Identification value */
    int setIdentification();
    int setIdentification(u16 i);
    u16 getIdentification();

    /* Fragment Offset */
    int setFragOffset();
    int setFragOffset(u16 f);
    u16 getFragOffset();

    /* Flags */
    int setRF();
    int unsetRF();
    bool getRF();
    int setDF();
    int unsetDF();
    bool getDF();
    int setMF();
    int unsetMF();
    bool getMF();

    /* Time to live */
    int setTTL();
    int setTTL(u8 t);
    u8 getTTL();

    /* Next protocol */
    int setNextProto(u8 p);
    int setNextProto(const char *p);
    u8 getNextProto();

    /* Checksum */
    int setSum();
    int setSum(u16 s);
    int setSumRandom();
    u16 getSum();

    /* Destination IP */
    int setDstIP(u32 d);
    int setDstIP(struct in_addr d);
    struct in_addr getDstIP();

    /* Source IP */
    int setSrcIP(u32 d);
    int setSrcIP(struct in_addr d);
    struct in_addr getSrcIP();

    /* IP Options */
    int setOpts(const char *txt);
    u8 *getOpts();
    u8 *getOpts(int *len);
    int printOptions();
    char *getOptionsString();

}; /* End of class IPv4Header */

#endif
