send_dg() refactor (bff43fc2) · Commits · e / os / android_packages_modules_DnsResolver

res_send.cpp

+103 −117

Original line number	Original line	Diff line number	Diff line
	@@ -875,22 +875,37 @@ retry:
	return n;		return n;
	}		}

			bool ignoreInvalidAnswer(res_state statp, const sockaddr_storage& from, const uint8_t* buf,
			int buflen, uint8_t* ans, int anssiz) {
			const HEADER* hp = (const HEADER)(const void)buf;
			HEADER* anhp = (HEADER)(void)ans;
			if (hp->id != anhp->id) {
			// response from old query, ignore it.
			LOG(DEBUG) << __func__ << ": old answer:";
			return true;
			}
			if (!res_ourserver_p(statp, (sockaddr)(void)&from)) {
			// response from wrong server? ignore it.
			LOG(DEBUG) << __func__ << ": not our server:";
			return true;
			}
			if (!res_queriesmatch(buf, buf + buflen, ans, ans + anssiz)) {
			// response contains wrong query? ignore it.
			LOG(DEBUG) << __func__ << ": wrong query name:";
			return true;
			}
			return false;
			}

	static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int buflen,		static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int buflen,
	uint8_t* ans, int anssiz, int* terrno, int ns, int* v_circuit, int* gotsomewhere,		uint8_t* ans, int anssiz, int* terrno, int ns, int* v_circuit, int* gotsomewhere,
	time_t* at, int* rcode, int* delay) {		time_t* at, int* rcode, int* delay) {
	*at = time(NULL);		*at = time(nullptr);
	*delay = 0;		*delay = 0;
	const HEADER* hp = (const HEADER) (const void) buf;
	HEADER* anhp = (HEADER) (void) ans;
	const struct sockaddr* nsap;
	int nsaplen;
	struct timespec now, timeout, finish, done;
	struct sockaddr_storage from;
	socklen_t fromlen;
	int resplen, n, s;

	nsap = get_nsaddr(statp, (size_t) ns);		const sockaddr* nsap = get_nsaddr(statp, (size_t)ns);
	nsaplen = sockaddrSize(nsap);		const int nsaplen = sockaddrSize(nsap);

	if (statp->nssocks[ns] == -1) {		if (statp->nssocks[ns] == -1) {
	statp->nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM \| SOCK_CLOEXEC, 0);		statp->nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM \| SOCK_CLOEXEC, 0);
	if (statp->nssocks[ns] < 0) {		if (statp->nssocks[ns] < 0) {
	@@ -931,20 +946,18 @@ static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int
	}		}
	LOG(DEBUG) << __func__ << ": new DG socket";		LOG(DEBUG) << __func__ << ": new DG socket";
	}		}
	s = statp->nssocks[ns];		if (send(statp->nssocks[ns], (const char*)buf, (size_t)buflen, 0) != buflen) {
	if (send(s, (const char*) buf, (size_t) buflen, 0) != buflen) {
	PLOG(DEBUG) << __func__ << ": send: ";		PLOG(DEBUG) << __func__ << ": send: ";
	res_nclose(statp);		res_nclose(statp);
	return 0;		return 0;
	}		}

			timespec timeout = get_timeout(statp, params, ns);
			timespec now = evNowTime();
			timespec finish = evAddTime(now, timeout);
			for (;;) {
	// Wait for reply.		// Wait for reply.
	timeout = get_timeout(statp, params, ns);		int n = retrying_poll(statp->nssocks[ns], POLLIN, &finish);
	now = evNowTime();
	finish = evAddTime(now, timeout);
	retry:
	n = retrying_poll(s, POLLIN, &finish);

	if (n == 0) {		if (n == 0) {
	*rcode = RCODE_TIMEOUT;		*rcode = RCODE_TIMEOUT;
	LOG(DEBUG) << __func__ << ": timeout";		LOG(DEBUG) << __func__ << ": timeout";
	@@ -956,10 +969,12 @@ retry:
	res_nclose(statp);		res_nclose(statp);
	return 0;		return 0;
	}		}

	errno = 0;		errno = 0;
	fromlen = sizeof(from);		sockaddr_storage from;
	resplen = recvfrom(s, (char) ans, (size_t) anssiz, 0, (struct sockaddr) (void*) &from,		socklen_t fromlen = sizeof(from);
	&fromlen);		int resplen = recvfrom(statp->nssocks[ns], (char*)ans, (size_t)anssiz, 0,
			(sockaddr)(void)&from, &fromlen);
	if (resplen <= 0) {		if (resplen <= 0) {
	PLOG(DEBUG) << __func__ << ": recvfrom: ";		PLOG(DEBUG) << __func__ << ": recvfrom: ";
	res_nclose(statp);		res_nclose(statp);
	@@ -967,58 +982,32 @@ retry:
	}		}
	*gotsomewhere = 1;		*gotsomewhere = 1;
	if (resplen < HFIXEDSZ) {		if (resplen < HFIXEDSZ) {
	/*		// Undersized message.
	* Undersized message.
	*/
	LOG(DEBUG) << __func__ << ": undersized: " << resplen;		LOG(DEBUG) << __func__ << ": undersized: " << resplen;
	*terrno = EMSGSIZE;		*terrno = EMSGSIZE;
	res_nclose(statp);		res_nclose(statp);
	return 0;		return 0;
	}		}
	if (hp->id != anhp->id) {
	/*		if (ignoreInvalidAnswer(statp, from, buf, buflen, ans, anssiz)) {
	* response from old query, ignore it.
	* XXX - potential security hazard could
	* be detected here.
	*/
	LOG(DEBUG) << __func__ << ": old answer:";
	res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
	goto retry;
	}
	if (!res_ourserver_p(statp, (struct sockaddr)(void)&from)) {
	/*
	* response from wrong server? ignore it.
	* XXX - potential security hazard could
	* be detected here.
	*/
	LOG(DEBUG) << __func__ << ": not our server:";
	res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);		res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
	goto retry;		continue;
	}		}

			HEADER* anhp = (HEADER)(void)ans;
	if (anhp->rcode == FORMERR && (statp->netcontext_flags & NET_CONTEXT_FLAG_USE_EDNS)) {		if (anhp->rcode == FORMERR && (statp->netcontext_flags & NET_CONTEXT_FLAG_USE_EDNS)) {
	/*		// Do not retry if the server do not understand EDNS0.
	* Do not retry if the server do not understand EDNS0.		// The case has to be captured here, as FORMERR packet do not
	* The case has to be captured here, as FORMERR packet do not		// carry query section, hence res_queriesmatch() returns 0.
	* carry query section, hence res_queriesmatch() returns 0.
	*/
	LOG(DEBUG) << __func__ << ": server rejected query with EDNS0:";		LOG(DEBUG) << __func__ << ": server rejected query with EDNS0:";
	res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);		res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
	/* record the error */		// record the error
	statp->_flags \|= RES_F_EDNS0ERR;		statp->_flags \|= RES_F_EDNS0ERR;
	res_nclose(statp);		res_nclose(statp);
	return 0;		return 0;
	}		}
	if (!res_queriesmatch(buf, buf + buflen, ans, ans + anssiz)) {
	/*		timespec done = evNowTime();
	* response contains wrong query? ignore it.
	* XXX - potential security hazard could
	* be detected here.
	*/
	LOG(DEBUG) << __func__ << ": wrong query name:";
	res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
	goto retry;
	}
	done = evNowTime();
	*delay = _res_stats_calculate_rtt(&done, &now);		*delay = _res_stats_calculate_rtt(&done, &now);
	if (anhp->rcode == SERVFAIL \|\| anhp->rcode == NOTIMP \|\| anhp->rcode == REFUSED) {		if (anhp->rcode == SERVFAIL \|\| anhp->rcode == NOTIMP \|\| anhp->rcode == REFUSED) {
	LOG(DEBUG) << __func__ << ": server rejected query:";		LOG(DEBUG) << __func__ << ": server rejected query:";
	@@ -1028,24 +1017,21 @@ retry:
	return 0;		return 0;
	}		}
	if (anhp->tc) {		if (anhp->tc) {
	/*		// To get the rest of answer,
	* To get the rest of answer,		// use TCP with same server.
	* use TCP with same server.
	*/
	LOG(DEBUG) << __func__ << ": truncated answer";		LOG(DEBUG) << __func__ << ": truncated answer";
	*v_circuit = 1;		*v_circuit = 1;
	res_nclose(statp);		res_nclose(statp);
	return 1;		return 1;
	}		}
	/*		// All is well, or the error is fatal. Signal that the
	* All is well, or the error is fatal. Signal that the		// next nameserver ought not be tried.
	* next nameserver ought not be tried.
	*/
	if (resplen > 0) {		if (resplen > 0) {
	*rcode = anhp->rcode;		*rcode = anhp->rcode;
	}		}
	return resplen;		return resplen;
	}		}
			}

	static void dump_error(const char* str, const struct sockaddr* address, int alen) {		static void dump_error(const char* str, const struct sockaddr* address, int alen) {
	char hbuf[NI_MAXHOST];		char hbuf[NI_MAXHOST];