unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned char *limit);
unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned char *limit);
int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **data, unsigned char *d, int n);
unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned char *limit);
unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned char *limit);
int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **data, unsigned char *d, int n);