SSL_CTX_set_psk_server_callback
SSL_CTX_set_psk_server_callback(ctx, psk_server_cb);
void SSL_CTX_set_psk_server_callback(SSL_CTX *ctx, SSL_psk_server_cb_func cb);
SSL_CTX_set_psk_server_callback(ctx, srvr_psk_callback);
SSL_CTX_set_psk_server_callback(ctx, srvr_psk_callback);
SSL_CTX_set_psk_server_callback(s_ctx, psk_server_callback);
SSL_CTX_set_psk_server_callback(s_ctx2, psk_server_callback);
SSL_CTX_set_psk_server_callback(sctx, psk_server_cb);