send_dg() refactor am: bff43fc2e5 am: b9688bdcd1 am: b7ca1449ab (73ec2056) · Commits · e / os / android_packages_modules_DnsResolver

res_send.cpp

+103 −117

Original line number	Diff line number	Diff line
		@@ -875,22 +875,37 @@ retry:
		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,
		uint8_t* ans, int anssiz, int* terrno, int ns, int* v_circuit, int* gotsomewhere,
		time_t* at, int* rcode, int* delay) {
		*at = time(NULL);
		*at = time(nullptr);
		*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);
		nsaplen = sockaddrSize(nsap);
		const sockaddr* nsap = get_nsaddr(statp, (size_t)ns);
		const int nsaplen = sockaddrSize(nsap);

		if (statp->nssocks[ns] == -1) {
		statp->nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM \| SOCK_CLOEXEC, 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";
		}
		s = statp->nssocks[ns];
		if (send(s, (const char*) buf, (size_t) buflen, 0) != buflen) {
		if (send(statp->nssocks[ns], (const char*)buf, (size_t)buflen, 0) != buflen) {
		PLOG(DEBUG) << __func__ << ": send: ";
		res_nclose(statp);
		return 0;
		}

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

		int n = retrying_poll(statp->nssocks[ns], POLLIN, &finish);
		if (n == 0) {
		*rcode = RCODE_TIMEOUT;
		LOG(DEBUG) << __func__ << ": timeout";
		@@ -956,10 +969,12 @@ retry:
		res_nclose(statp);
		return 0;
		}

		errno = 0;
		fromlen = sizeof(from);
		resplen = recvfrom(s, (char) ans, (size_t) anssiz, 0, (struct sockaddr) (void*) &from,
		&fromlen);
		sockaddr_storage from;
		socklen_t fromlen = sizeof(from);
		int resplen = recvfrom(statp->nssocks[ns], (char*)ans, (size_t)anssiz, 0,
		(sockaddr)(void)&from, &fromlen);
		if (resplen <= 0) {
		PLOG(DEBUG) << __func__ << ": recvfrom: ";
		res_nclose(statp);
		@@ -967,58 +982,32 @@ retry:
		}
		*gotsomewhere = 1;
		if (resplen < HFIXEDSZ) {
		/*
		* Undersized message.
		*/
		// Undersized message.
		LOG(DEBUG) << __func__ << ": undersized: " << resplen;
		*terrno = EMSGSIZE;
		res_nclose(statp);
		return 0;
		}
		if (hp->id != anhp->id) {
		/*
		* 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:";

		if (ignoreInvalidAnswer(statp, from, buf, buflen, ans, anssiz)) {
		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)) {
		/*
		* Do not retry if the server do not understand EDNS0.
		* The case has to be captured here, as FORMERR packet do not
		* carry query section, hence res_queriesmatch() returns 0.
		*/
		// Do not retry if the server do not understand EDNS0.
		// The case has to be captured here, as FORMERR packet do not
		// carry query section, hence res_queriesmatch() returns 0.
		LOG(DEBUG) << __func__ << ": server rejected query with EDNS0:";
		res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
		/* record the error */
		// record the error
		statp->_flags \|= RES_F_EDNS0ERR;
		res_nclose(statp);
		return 0;
		}
		if (!res_queriesmatch(buf, buf + buflen, ans, ans + anssiz)) {
		/*
		* 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();

		timespec done = evNowTime();
		*delay = _res_stats_calculate_rtt(&done, &now);
		if (anhp->rcode == SERVFAIL \|\| anhp->rcode == NOTIMP \|\| anhp->rcode == REFUSED) {
		LOG(DEBUG) << __func__ << ": server rejected query:";
		@@ -1028,24 +1017,21 @@ retry:
		return 0;
		}
		if (anhp->tc) {
		/*
		* To get the rest of answer,
		* use TCP with same server.
		*/
		// To get the rest of answer,
		// use TCP with same server.
		LOG(DEBUG) << __func__ << ": truncated answer";
		*v_circuit = 1;
		res_nclose(statp);
		return 1;
		}
		/*
		* All is well, or the error is fatal. Signal that the
		* next nameserver ought not be tried.
		*/
		// All is well, or the error is fatal. Signal that the
		// next nameserver ought not be tried.
		if (resplen > 0) {
		*rcode = anhp->rcode;
		}
		return resplen;
		}
		}

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