+ void (*log_msg)(void *ctx, const char *msg);
+ int (*get_erp_send_reauth_start)(void *ctx);
+ const char * (*get_erp_domain)(void *ctx);
+ struct eap_server_erp_key * (*erp_get_key)(void *ctx,
+ const char *keyname);
+ int (*erp_add_key)(void *ctx, struct eap_server_erp_key *erp);