add: auth_hf_len = 0;
context: static inline int challenge(struct sip_msg* _msg, char* _realm, int _qop, 			    int _code, char* _message, char* _challenge_msg){	int auth_hf_len;	struct hdr_field* h;	auth_body_t* cred = 0;	switch(_code) {	case 401: get_authorized_cred(_msg->authorization, &h); break;	case 407: get_authorized_cred(_msg->proxy_auth, &h);    break;	}	if (h) cred = (auth_body_t*)(h->parsed);	if (cred != 0) {		if (cred->nonce_retries > retry_count) {			DBG("challenge(): Retry count exceeded, sending Forbidden\n");			_code = 403;			_message = MESSAGE_403;		} else {			if (cred->stale == 0) {				cred->nonce_retries++;			} else {				cred->nonce_retries = 0;			}						build_auth_hf(cred->nonce_retries, cred->stale, 				      _realm, auth_hf, &auth_hf_len,				      _qop, _challenge_msg);		}	} else {		build_auth_hf(0, 0, _realm, auth_hf, &auth_hf_len, _qop, _challenge_msg);	}		if (send_resp(_msg, _code, _message, auth_hf, auth_hf_len) == -1) {		LOG(L_ERR, "www_challenge(): Error while sending response\n");		return -1;	}	return 0;}