Merge "res_nsend() refactor" (8ac099a4) · Commits · e / os / android_packages_modules_DnsResolver

res_send.cpp

+67 −108

Original line number	Original line	Diff line number	Diff line
	@@ -397,24 +397,20 @@ static DnsQueryEvent* addDnsQueryEvent(NetworkDnsEventReported* event) {

	int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int anssiz, int* rcode,		int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int anssiz, int* rcode,
	uint32_t flags) {		uint32_t flags) {
	int gotsomewhere, terrno, v_circuit, resplen, n;		LOG(DEBUG) << __func__;
	ResolvCacheStatus cache_status = RESOLV_CACHE_UNSUPPORTED;

			// Should not happen
	if (anssiz < HFIXEDSZ) {		if (anssiz < HFIXEDSZ) {
	// TODO: Remove errno once callers stop using it		// TODO: Remove errno once callers stop using it
	errno = EINVAL;		errno = EINVAL;
	return -EINVAL;		return -EINVAL;
	}		}
	LOG(DEBUG) << __func__;
	res_pquery(buf, buflen);		res_pquery(buf, buflen);

	v_circuit = buflen > PACKETSZ;
	gotsomewhere = 0;
	terrno = ETIMEDOUT;

	int anslen = 0;		int anslen = 0;
	Stopwatch cacheStopwatch;		Stopwatch cacheStopwatch;
	cache_status = resolv_cache_lookup(statp->netid, buf, buflen, ans, anssiz, &anslen, flags);		ResolvCacheStatus cache_status =
			resolv_cache_lookup(statp->netid, buf, buflen, ans, anssiz, &anslen, flags);
	const int32_t cacheLatencyUs = saturate_cast<int32_t>(cacheStopwatch.timeTakenUs());		const int32_t cacheLatencyUs = saturate_cast<int32_t>(cacheStopwatch.timeTakenUs());
	if (cache_status == RESOLV_CACHE_FOUND) {		if (cache_status == RESOLV_CACHE_FOUND) {
	HEADER* hp = (HEADER)(void)ans;		HEADER* hp = (HEADER)(void)ans;
	@@ -442,8 +438,8 @@ int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int
	// DoT		// DoT
	if (!(statp->netcontext_flags & NET_CONTEXT_FLAG_USE_LOCAL_NAMESERVERS)) {		if (!(statp->netcontext_flags & NET_CONTEXT_FLAG_USE_LOCAL_NAMESERVERS)) {
	bool fallback = false;		bool fallback = false;
	resplen = res_tls_send(statp, Slice(const_cast<uint8_t*>(buf), buflen), Slice(ans, anssiz),		int resplen = res_tls_send(statp, Slice(const_cast<uint8_t*>(buf), buflen),
	rcode, &fallback);		Slice(ans, anssiz), rcode, &fallback);
	if (resplen > 0) {		if (resplen > 0) {
	LOG(DEBUG) << __func__ << ": got answer from DoT";		LOG(DEBUG) << __func__ << ": got answer from DoT";
	res_pquery(ans, resplen);		res_pquery(ans, resplen);
	@@ -454,7 +450,7 @@ int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int
	}		}
	if (!fallback) {		if (!fallback) {
	_resolv_cache_query_failed(statp->netid, buf, buflen, flags);		_resolv_cache_query_failed(statp->netid, buf, buflen, flags);
	return -terrno;		return -ETIMEDOUT;
	}		}
	}		}

	@@ -478,90 +474,62 @@ int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int
	res_set_usable_server(selectedServer, statp->nscount, usable_servers);		res_set_usable_server(selectedServer, statp->nscount, usable_servers);
	}		}

	/*		// Send request, RETRY times, or until successful.
	* Send request, RETRY times, or until successful.
	*/
	int retryTimes = (flags & ANDROID_RESOLV_NO_RETRY) ? 1 : params.retry_count;		int retryTimes = (flags & ANDROID_RESOLV_NO_RETRY) ? 1 : params.retry_count;
			int useTcp = buflen > PACKETSZ;
			int gotsomewhere = 0;
			int terrno = ETIMEDOUT;

	for (int attempt = 0; attempt < retryTimes; ++attempt) {		for (int attempt = 0; attempt < retryTimes; ++attempt) {
			for (int ns = 0; ns < statp->nscount; ++ns) {
	for (int ns = 0; ns < statp->nscount; ns++) {
	if (!usable_servers[ns]) continue;		if (!usable_servers[ns]) continue;
	int nsaplen;
	time_t now = 0;
	int delay = 0;
	*rcode = RCODE_INTERNAL_ERROR;		*rcode = RCODE_INTERNAL_ERROR;

			// Get server addr
	const sockaddr* nsap = get_nsaddr(statp, ns);		const sockaddr* nsap = get_nsaddr(statp, ns);
	nsaplen = sockaddrSize(nsap);		const int nsaplen = sockaddrSize(nsap);

	same_ns:
	static const int niflags = NI_NUMERICHOST \| NI_NUMERICSERV;		static const int niflags = NI_NUMERICHOST \| NI_NUMERICSERV;
	char abuf[NI_MAXHOST];		char abuf[NI_MAXHOST];
	DnsQueryEvent* dnsQueryEvent = addDnsQueryEvent(statp->event);
	dnsQueryEvent->set_cache_hit(static_cast<CacheStatus>(cache_status));

	if (getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf), NULL, 0, niflags) == 0)		if (getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf), NULL, 0, niflags) == 0)
	LOG(DEBUG) << __func__ << ": Querying server (# " << ns + 1		LOG(DEBUG) << __func__ << ": Querying server (# " << ns + 1
	<< ") address = " << abuf;		<< ") address = " << abuf;

			::android::net::Protocol query_proto = useTcp ? PROTO_TCP : PROTO_UDP;
			time_t now = 0;
			int delay = 0;
			bool fallbackTCP = false;
			const bool shouldRecordStats = (attempt == 0);
			int resplen;
	Stopwatch queryStopwatch;		Stopwatch queryStopwatch;
	if (v_circuit) {		if (useTcp) {
	/* Use VC; at most one attempt per server. */		// TCP; at most one attempt per server.
	bool shouldRecordStats = (attempt == 0);
	attempt = retryTimes;		attempt = retryTimes;
			resplen = send_vc(statp, &params, buf, buflen, ans, anssiz, &terrno, ns, &now,
	n = send_vc(statp, &params, buf, buflen, ans, anssiz, &terrno, ns, &now, rcode,		rcode, &delay);
	&delay);

	dnsQueryEvent->set_latency_micros(
	saturate_cast<int32_t>(queryStopwatch.timeTakenUs()));
	dnsQueryEvent->set_dns_server_index(ns);
	dnsQueryEvent->set_ip_version(ipFamilyToIPVersion(nsap->sa_family));
	dnsQueryEvent->set_retry_times(attempt);
	dnsQueryEvent->set_rcode(static_cast<NsRcode>(*rcode));
	dnsQueryEvent->set_protocol(PROTO_TCP);
	dnsQueryEvent->set_type(getQueryType(buf, buflen));

	/*
	* Only record stats the first time we try a query. This ensures that
	* queries that deterministically fail (e.g., a name that always returns
	* SERVFAIL or times out) do not unduly affect the stats.
	*/
	if (shouldRecordStats) {
	res_sample sample;
	_res_stats_set_sample(&sample, now, *rcode, delay);
	resolv_cache_add_resolver_stats_sample(statp->netid, revision_id, nsap, sample,
	params.max_samples);
	resolv_stats_add(statp->netid, IPSockAddr::toIPSockAddr(*nsap), dnsQueryEvent);
	}

	LOG(INFO) << __func__ << ": used send_vc " << n;

	if (n < 0) {
	_resolv_cache_query_failed(statp->netid, buf, buflen, flags);
	res_nclose(statp);
	return -terrno;
	};
	if (n == 0) goto next_ns;
	resplen = n;
	} else {		} else {
	/* Use datagrams. */		// UDP
	LOG(INFO) << __func__ << ": using send_dg";		resplen = send_dg(statp, &params, buf, buflen, ans, anssiz, &terrno, ns, &useTcp,

	n = send_dg(statp, &params, buf, buflen, ans, anssiz, &terrno, ns, &v_circuit,
	&gotsomewhere, &now, rcode, &delay);		&gotsomewhere, &now, rcode, &delay);
			fallbackTCP = useTcp ? true : false;
			}
			LOG(INFO) << __func__ << ": used send_" << ((useTcp) ? "vc " : "dg ") << resplen;

	dnsQueryEvent->set_latency_micros(		DnsQueryEvent* dnsQueryEvent = addDnsQueryEvent(statp->event);
	saturate_cast<int32_t>(queryStopwatch.timeTakenUs()));		dnsQueryEvent->set_cache_hit(static_cast<CacheStatus>(cache_status));
			dnsQueryEvent->set_latency_micros(saturate_cast<int32_t>(queryStopwatch.timeTakenUs()));
	dnsQueryEvent->set_dns_server_index(ns);		dnsQueryEvent->set_dns_server_index(ns);
	dnsQueryEvent->set_ip_version(ipFamilyToIPVersion(nsap->sa_family));		dnsQueryEvent->set_ip_version(ipFamilyToIPVersion(nsap->sa_family));
	dnsQueryEvent->set_retry_times(attempt);		dnsQueryEvent->set_retry_times(attempt);
	dnsQueryEvent->set_rcode(static_cast<NsRcode>(*rcode));		dnsQueryEvent->set_rcode(static_cast<NsRcode>(*rcode));
	dnsQueryEvent->set_protocol(PROTO_UDP);		dnsQueryEvent->set_protocol(query_proto);
	dnsQueryEvent->set_type(getQueryType(buf, buflen));		dnsQueryEvent->set_type(getQueryType(buf, buflen));

	/* Only record stats the first time we try a query. See above. */		// Only record stats the first time we try a query. This ensures that
	if (attempt == 0) {		// queries that deterministically fail (e.g., a name that always returns
			// SERVFAIL or times out) do not unduly affect the stats.
			if (shouldRecordStats) {
	res_sample sample;		res_sample sample;
	_res_stats_set_sample(&sample, now, *rcode, delay);		_res_stats_set_sample(&sample, now, *rcode, delay);
	resolv_cache_add_resolver_stats_sample(statp->netid, revision_id, nsap, sample,		resolv_cache_add_resolver_stats_sample(statp->netid, revision_id, nsap, sample,
	@@ -569,17 +537,16 @@ int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int
	resolv_stats_add(statp->netid, IPSockAddr::toIPSockAddr(*nsap), dnsQueryEvent);		resolv_stats_add(statp->netid, IPSockAddr::toIPSockAddr(*nsap), dnsQueryEvent);
	}		}

	LOG(INFO) << __func__ << ": used send_dg " << n;		if (resplen == 0) continue;
			if (fallbackTCP) {
	if (n < 0) {		ns--;
			continue;
			}
			if (resplen < 0) {
	_resolv_cache_query_failed(statp->netid, buf, buflen, flags);		_resolv_cache_query_failed(statp->netid, buf, buflen, flags);
	res_nclose(statp);		res_nclose(statp);
	return -terrno;		return -terrno;
	};		};
	if (n == 0) goto next_ns;
	if (v_circuit) goto same_ns;
	resplen = n;
	}

	LOG(DEBUG) << __func__ << ": got answer:";		LOG(DEBUG) << __func__ << ": got answer:";
	res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);		res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
	@@ -589,23 +556,15 @@ int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int
	}		}
	res_nclose(statp);		res_nclose(statp);
	return (resplen);		return (resplen);
	next_ns:;
	} // for each ns		} // for each ns
	} // for each retry		} // for each retry
	res_nclose(statp);		res_nclose(statp);
	if (!v_circuit) {		terrno = useTcp ? terrno : gotsomewhere ? ETIMEDOUT : ECONNREFUSED;
	if (!gotsomewhere) {
	// TODO: Remove errno once callers stop using it
	errno = ECONNREFUSED; /* no nameservers found */
	terrno = ECONNREFUSED;
	} else {
	// TODO: Remove errno once callers stop using it		// TODO: Remove errno once callers stop using it
	errno = ETIMEDOUT; /* no answer obtained */		errno = useTcp ? terrno
	terrno = ETIMEDOUT;		: gotsomewhere ? ETIMEDOUT /* no answer obtained */
	}		: ECONNREFUSED /* no nameservers found */;
	} else {
	errno = terrno;
	}
	_resolv_cache_query_failed(statp->netid, buf, buflen, flags);		_resolv_cache_query_failed(statp->netid, buf, buflen, flags);
	return -terrno;		return -terrno;
	}		}