/*
 *Socks client 'method request'
 */
struct socksv5cli_meth_req {
    uint8_t version;   /* socks version X'05' */
    uint8_t n_methods; /* number of methods specified in method[..] */
    uint8_t method[256]; /* client requesting method[n_methods] */
};

/*
 *Server selected 'method  selection response'
 * from what client requested in his socksv5cli_req.method[...]
 */
struct socksv5serv_meth_sel_res {
    uint8_t version;  /* socks version X'05' */
    uint8_t meth_sel; /* method selected */
};

/*
  The values currently defined for METHOD are:
o  X'00' NO AUTHENTICATION REQUIRED
o  X'01' GSSAPI
o  X'02' USERNAME/PASSWORD
o  X'03' to X'7F' IANA ASSIGNED
o  X'80' to X'FE' RESERVED FOR PRIVATE METHODS
o  X'FF' NO ACCEPTABLE METHODS

The client and server then enter a method-specific sub-negotiation.
*/
#define NOAUTH 0x00 /* no authen. required */
#define GSSAPI 0x01 /* GSSAPI */
#define USRPAS 0x02 /* user password */
#define NONEAC 0xFF /* no acceptable */