// Structures required to use functions in ICMP.DLL

typedef struct {
    unsigned char Ttl;                         // Time To Live
    unsigned char Tos;                         // Type Of Service
    unsigned char Flags;                       // IP header flags
    unsigned char OptionsSize;                 // Size in bytes of options data
    unsigned char *OptionsData;                // Pointer to options data
} IP_OPTION_INFORMATION, * PIP_OPTION_INFORMATION;

typedef struct {
    DWORD Address;                             // Replying address
    unsigned long  Status;                     // Reply status
    unsigned long  RoundTripTime;              // RTT in milliseconds
    unsigned short DataSize;                   // Echo data size
    unsigned short Reserved;                   // Reserved for system use
    void *Data;                                // Pointer to the echo data
    IP_OPTION_INFORMATION Options;             // Reply options
} IP_ECHO_REPLY, * PIP_ECHO_REPLY;