Use unique_fd instead of int for sockets (adb0f5b9) · Commits · e / os / android_packages_modules_DnsResolver

res_init.cpp

+8 −35

Original line number	Original line	Diff line number	Diff line
	@@ -94,23 +94,11 @@

	void res_init(ResState* statp, const struct android_net_context* _Nonnull netcontext,		void res_init(ResState* statp, const struct android_net_context* _Nonnull netcontext,
	android::net::NetworkDnsEventReported* _Nonnull event) {		android::net::NetworkDnsEventReported* _Nonnull event) {
	memset(statp, 0, sizeof *statp);

	statp->netid = netcontext->dns_netid;		statp->netid = netcontext->dns_netid;
	statp->uid = netcontext->uid;		statp->uid = netcontext->uid;
	statp->pid = netcontext->pid;		statp->pid = netcontext->pid;
			statp->nscount = 1;
	statp->id = arc4random_uniform(65536);		statp->id = arc4random_uniform(65536);
	statp->_mark = netcontext->dns_mark;
	statp->netcontext_flags = netcontext->flags;
	statp->event = event;

	statp->ndots = 1;
	statp->_vcsock = -1;

	for (int ns = 0; ns < MAXNS; ns++) {
	statp->nssocks[ns] = -1;
	}

	// The following dummy initialization is probably useless because		// The following dummy initialization is probably useless because
	// it's overwritten later by resolv_populate_res_for_net().		// it's overwritten later by resolv_populate_res_for_net().
	// TODO: check if it's safe to remove.		// TODO: check if it's safe to remove.
	@@ -120,28 +108,13 @@ void res_init(ResState* statp, const struct android_net_context* _Nonnull netcon
	.sin.sin_port = htons(NAMESERVER_PORT),		.sin.sin_port = htons(NAMESERVER_PORT),
	};		};
	memcpy(&statp->nsaddrs, &u, sizeof(u));		memcpy(&statp->nsaddrs, &u, sizeof(u));
	statp->nscount = 1;
	}

	/*
	* This routine is for closing the socket if a virtual circuit is used and
	* the program wants to close it. This provides support for endhostent()
	* which expects to close the socket.
	*
	* This routine is not expected to be user visible.
	*/
	void res_nclose(res_state statp) {
	int ns;

	if (statp->_vcsock >= 0) {		for (auto& sock : statp->nssocks) {
	(void) close(statp->_vcsock);		sock.reset();
	statp->_vcsock = -1;
	statp->_flags &= ~RES_F_VC;
	}
	for (ns = 0; ns < MAXNS; ns++) {
	if (statp->nssocks[ns] != -1) {
	close(statp->nssocks[ns]);
	statp->nssocks[ns] = -1;
	}
	}		}
			statp->ndots = 1;
			statp->_mark = netcontext->dns_mark;
			statp->tcp_nssock.reset();
			statp->event = event;
			statp->netcontext_flags = netcontext->flags;
	}		}

res_send.cpp

+37 −40

Original line number	Original line	Diff line number	Diff line
	@@ -555,7 +555,7 @@ int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int
	}		}
	if (resplen < 0) {		if (resplen < 0) {
	_resolv_cache_query_failed(statp->netid, buf, buflen, flags);		_resolv_cache_query_failed(statp->netid, buf, buflen, flags);
	res_nclose(statp);		statp->closeSockets();
	return -terrno;		return -terrno;
	};		};

	@@ -565,11 +565,11 @@ int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int
	if (cache_status == RESOLV_CACHE_NOTFOUND) {		if (cache_status == RESOLV_CACHE_NOTFOUND) {
	resolv_cache_add(statp->netid, buf, buflen, ans, resplen);		resolv_cache_add(statp->netid, buf, buflen, ans, resplen);
	}		}
	res_nclose(statp);		statp->closeSockets();
	return (resplen);		return (resplen);
	} // for each ns		} // for each ns
	} // for each retry		} // for each retry
	res_nclose(statp);		statp->closeSockets();
	terrno = useTcp ? terrno : gotsomewhere ? ETIMEDOUT : ECONNREFUSED;		terrno = useTcp ? terrno : gotsomewhere ? ETIMEDOUT : ECONNREFUSED;
	// TODO: Remove errno once callers stop using it		// TODO: Remove errno once callers stop using it
	errno = useTcp ? terrno		errno = useTcp ? terrno
	@@ -631,25 +631,24 @@ same_ns:
	struct timespec now = evNowTime();		struct timespec now = evNowTime();

	/* Are we still talking to whom we want to talk to? */		/* Are we still talking to whom we want to talk to? */
	if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) {		if (statp->tcp_nssock >= 0 && (statp->_flags & RES_F_VC) != 0) {
	struct sockaddr_storage peer;		struct sockaddr_storage peer;
	socklen_t size = sizeof peer;		socklen_t size = sizeof peer;
	unsigned old_mark;		unsigned old_mark;
	socklen_t mark_size = sizeof(old_mark);		socklen_t mark_size = sizeof(old_mark);
	if (getpeername(statp->_vcsock, (struct sockaddr) (void) &peer, &size) < 0 \|\|		if (getpeername(statp->tcp_nssock, (struct sockaddr)(void)&peer, &size) < 0 \|\|
	!sock_eq((struct sockaddr)(void)&peer, nsap) \|\|		!sock_eq((struct sockaddr)(void)&peer, nsap) \|\|
	getsockopt(statp->_vcsock, SOL_SOCKET, SO_MARK, &old_mark, &mark_size) < 0 \|\|		getsockopt(statp->tcp_nssock, SOL_SOCKET, SO_MARK, &old_mark, &mark_size) < 0 \|\|
	old_mark != statp->_mark) {		old_mark != statp->_mark) {
	res_nclose(statp);		statp->closeSockets();
	statp->_flags &= ~RES_F_VC;
	}		}
	}		}

	if (statp->_vcsock < 0 \|\| (statp->_flags & RES_F_VC) == 0) {		if (statp->tcp_nssock < 0 \|\| (statp->_flags & RES_F_VC) == 0) {
	if (statp->_vcsock >= 0) res_nclose(statp);		if (statp->tcp_nssock >= 0) statp->closeSockets();

	statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM \| SOCK_CLOEXEC, 0);		statp->tcp_nssock.reset(socket(nsap->sa_family, SOCK_STREAM \| SOCK_CLOEXEC, 0));
	if (statp->_vcsock < 0) {		if (statp->tcp_nssock < 0) {
	switch (errno) {		switch (errno) {
	case EPROTONOSUPPORT:		case EPROTONOSUPPORT:
	case EPFNOSUPPORT:		case EPFNOSUPPORT:
	@@ -662,9 +661,9 @@ same_ns:
	return -1;		return -1;
	}		}
	}		}
	resolv_tag_socket(statp->_vcsock, statp->uid, statp->pid);		resolv_tag_socket(statp->tcp_nssock, statp->uid, statp->pid);
	if (statp->_mark != MARK_UNSET) {		if (statp->_mark != MARK_UNSET) {
	if (setsockopt(statp->_vcsock, SOL_SOCKET, SO_MARK, &statp->_mark,		if (setsockopt(statp->tcp_nssock, SOL_SOCKET, SO_MARK, &statp->_mark,
	sizeof(statp->_mark)) < 0) {		sizeof(statp->_mark)) < 0) {
	*terrno = errno;		*terrno = errno;
	PLOG(DEBUG) << __func__ << ": setsockopt: ";		PLOG(DEBUG) << __func__ << ": setsockopt: ";
	@@ -672,17 +671,17 @@ same_ns:
	}		}
	}		}
	errno = 0;		errno = 0;
	if (random_bind(statp->_vcsock, nsap->sa_family) < 0) {		if (random_bind(statp->tcp_nssock, nsap->sa_family) < 0) {
	*terrno = errno;		*terrno = errno;
	dump_error("bind/vc", nsap, nsaplen);		dump_error("bind/vc", nsap, nsaplen);
	res_nclose(statp);		statp->closeSockets();
	return (0);		return (0);
	}		}
	if (connect_with_timeout(statp->_vcsock, nsap, (socklen_t) nsaplen,		if (connect_with_timeout(statp->tcp_nssock, nsap, (socklen_t)nsaplen,
	get_timeout(statp, params, ns)) < 0) {		get_timeout(statp, params, ns)) < 0) {
	*terrno = errno;		*terrno = errno;
	dump_error("connect/vc", nsap, nsaplen);		dump_error("connect/vc", nsap, nsaplen);
	res_nclose(statp);		statp->closeSockets();
	/*		/*
	* The way connect_with_timeout() is implemented prevents us from reliably		* The way connect_with_timeout() is implemented prevents us from reliably
	* determining whether this was really a timeout or e.g. ECONNREFUSED. Since		* determining whether this was really a timeout or e.g. ECONNREFUSED. Since
	@@ -705,10 +704,10 @@ same_ns:
	{.iov_base = &len, .iov_len = INT16SZ},		{.iov_base = &len, .iov_len = INT16SZ},
	{.iov_base = const_cast<uint8_t*>(buf), .iov_len = static_cast<size_t>(buflen)},		{.iov_base = const_cast<uint8_t*>(buf), .iov_len = static_cast<size_t>(buflen)},
	};		};
	if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) {		if (writev(statp->tcp_nssock, iov, 2) != (INT16SZ + buflen)) {
	*terrno = errno;		*terrno = errno;
	PLOG(DEBUG) << __func__ << ": write failed: ";		PLOG(DEBUG) << __func__ << ": write failed: ";
	res_nclose(statp);		statp->closeSockets();
	return (0);		return (0);
	}		}
	/*		/*
	@@ -717,14 +716,14 @@ same_ns:
	read_len:		read_len:
	cp = ans;		cp = ans;
	len = INT16SZ;		len = INT16SZ;
	while ((n = read(statp->_vcsock, (char*) cp, (size_t) len)) > 0) {		while ((n = read(statp->tcp_nssock, (char*)cp, (size_t)len)) > 0) {
	cp += n;		cp += n;
	if ((len -= n) == 0) break;		if ((len -= n) == 0) break;
	}		}
	if (n <= 0) {		if (n <= 0) {
	*terrno = errno;		*terrno = errno;
	PLOG(DEBUG) << __func__ << ": read failed: ";		PLOG(DEBUG) << __func__ << ": read failed: ";
	res_nclose(statp);		statp->closeSockets();
	/*		/*
	* A long running process might get its TCP		* A long running process might get its TCP
	* connection reset if the remote server was		* connection reset if the remote server was
	@@ -736,10 +735,8 @@ read_len:
	*/		*/
	if (*terrno == ECONNRESET && !connreset) {		if (*terrno == ECONNRESET && !connreset) {
	connreset = 1;		connreset = 1;
	res_nclose(statp);
	goto same_ns;		goto same_ns;
	}		}
	res_nclose(statp);
	return (0);		return (0);
	}		}
	uint16_t resplen = ntohs(reinterpret_cast<const uint16_t>(ans));		uint16_t resplen = ntohs(reinterpret_cast<const uint16_t>(ans));
	@@ -755,18 +752,18 @@ read_len:
	*/		*/
	LOG(DEBUG) << __func__ << ": undersized: " << len;		LOG(DEBUG) << __func__ << ": undersized: " << len;
	*terrno = EMSGSIZE;		*terrno = EMSGSIZE;
	res_nclose(statp);		statp->closeSockets();
	return (0);		return (0);
	}		}
	cp = ans;		cp = ans;
	while (len != 0 && (n = read(statp->_vcsock, (char*) cp, (size_t) len)) > 0) {		while (len != 0 && (n = read(statp->tcp_nssock, (char*)cp, (size_t)len)) > 0) {
	cp += n;		cp += n;
	len -= n;		len -= n;
	}		}
	if (n <= 0) {		if (n <= 0) {
	*terrno = errno;		*terrno = errno;
	PLOG(DEBUG) << __func__ << ": read(vc): ";		PLOG(DEBUG) << __func__ << ": read(vc): ";
	res_nclose(statp);		statp->closeSockets();
	return (0);		return (0);
	}		}

	@@ -779,7 +776,7 @@ read_len:
	while (len != 0) {		while (len != 0) {
	char junk[PACKETSZ];		char junk[PACKETSZ];

	n = read(statp->_vcsock, junk, (len > sizeof junk) ? sizeof junk : len);		n = read(statp->tcp_nssock, junk, (len > sizeof junk) ? sizeof junk : len);
	if (n > 0)		if (n > 0)
	len -= n;		len -= n;
	else		else
	@@ -907,7 +904,7 @@ static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int
	const int 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].reset(socket(nsap->sa_family, SOCK_DGRAM \| SOCK_CLOEXEC, 0));
	if (statp->nssocks[ns] < 0) {		if (statp->nssocks[ns] < 0) {
	switch (errno) {		switch (errno) {
	case EPROTONOSUPPORT:		case EPROTONOSUPPORT:
	@@ -926,7 +923,7 @@ static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int
	if (statp->_mark != MARK_UNSET) {		if (statp->_mark != MARK_UNSET) {
	if (setsockopt(statp->nssocks[ns], SOL_SOCKET, SO_MARK, &(statp->_mark),		if (setsockopt(statp->nssocks[ns], SOL_SOCKET, SO_MARK, &(statp->_mark),
	sizeof(statp->_mark)) < 0) {		sizeof(statp->_mark)) < 0) {
	res_nclose(statp);		statp->closeSockets();
	return -1;		return -1;
	}		}
	}		}
	@@ -936,19 +933,19 @@ static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int
	// a nameserver without timing out.		// a nameserver without timing out.
	if (random_bind(statp->nssocks[ns], nsap->sa_family) < 0) {		if (random_bind(statp->nssocks[ns], nsap->sa_family) < 0) {
	dump_error("bind(dg)", nsap, nsaplen);		dump_error("bind(dg)", nsap, nsaplen);
	res_nclose(statp);		statp->closeSockets();
	return (0);		return (0);
	}		}
	if (connect(statp->nssocks[ns], nsap, (socklen_t)nsaplen) < 0) {		if (connect(statp->nssocks[ns], nsap, (socklen_t)nsaplen) < 0) {
	dump_error("connect(dg)", nsap, nsaplen);		dump_error("connect(dg)", nsap, nsaplen);
	res_nclose(statp);		statp->closeSockets();
	return (0);		return (0);
	}		}
	LOG(DEBUG) << __func__ << ": new DG socket";		LOG(DEBUG) << __func__ << ": new DG socket";
	}		}
	if (send(statp->nssocks[ns], (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: ";		PLOG(DEBUG) << __func__ << ": send: ";
	res_nclose(statp);		statp->closeSockets();
	return 0;		return 0;
	}		}

	@@ -966,7 +963,7 @@ static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int
	}		}
	if (n < 0) {		if (n < 0) {
	PLOG(DEBUG) << __func__ << ": poll: ";		PLOG(DEBUG) << __func__ << ": poll: ";
	res_nclose(statp);		statp->closeSockets();
	return 0;		return 0;
	}		}

	@@ -977,7 +974,7 @@ static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int
	(sockaddr)(void)&from, &fromlen);		(sockaddr)(void)&from, &fromlen);
	if (resplen <= 0) {		if (resplen <= 0) {
	PLOG(DEBUG) << __func__ << ": recvfrom: ";		PLOG(DEBUG) << __func__ << ": recvfrom: ";
	res_nclose(statp);		statp->closeSockets();
	return 0;		return 0;
	}		}
	*gotsomewhere = 1;		*gotsomewhere = 1;
	@@ -985,7 +982,7 @@ static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int
	// Undersized message.		// Undersized message.
	LOG(DEBUG) << __func__ << ": undersized: " << resplen;		LOG(DEBUG) << __func__ << ": undersized: " << resplen;
	*terrno = EMSGSIZE;		*terrno = EMSGSIZE;
	res_nclose(statp);		statp->closeSockets();
	return 0;		return 0;
	}		}

	@@ -1003,7 +1000,7 @@ static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int
	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);		statp->closeSockets();
	return 0;		return 0;
	}		}

	@@ -1012,7 +1009,7 @@ static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int
	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:";
	res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);		res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
	res_nclose(statp);		statp->closeSockets();
	*rcode = anhp->rcode;		*rcode = anhp->rcode;
	return 0;		return 0;
	}		}
	@@ -1021,7 +1018,7 @@ static int send_dg(res_state statp, res_params* params, const uint8_t* buf, int
	// 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);		statp->closeSockets();
	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

resolv_private.h

+27 −17

Original line number	Original line	Diff line number	Diff line
	@@ -49,6 +49,7 @@
	#pragma once		#pragma once

	#include <android-base/logging.h>		#include <android-base/logging.h>
			#include <android-base/unique_fd.h>
	#include <net/if.h>		#include <net/if.h>
	#include <time.h>		#include <time.h>
	#include <string>		#include <string>
	@@ -73,6 +74,10 @@
	#define RES_TIMEOUT 5000 /* min. milliseconds between retries */		#define RES_TIMEOUT 5000 /* min. milliseconds between retries */
	#define RES_DFLRETRY 2 /* Default #/tries. */		#define RES_DFLRETRY 2 /* Default #/tries. */

			// Flags for res_state->_flags
			#define RES_F_VC 0x00000001 // socket is TCP
			#define RES_F_EDNS0ERR 0x00000004 // EDNS0 caused errors

	// Holds either a sockaddr_in or a sockaddr_in6.		// Holds either a sockaddr_in or a sockaddr_in6.
	union sockaddr_union {		union sockaddr_union {
	struct sockaddr sa;		struct sockaddr sa;
	@@ -82,21 +87,31 @@ union sockaddr_union {
	constexpr int MAXPACKET = 8 * 1024;		constexpr int MAXPACKET = 8 * 1024;

	struct ResState {		struct ResState {
			void closeSockets() {
			tcp_nssock.reset();
			_flags &= ~RES_F_VC;

			for (auto& sock : nssocks) {
			sock.reset();
			}
			}
			// clang-format off
	unsigned netid; // NetId: cache key and socket mark		unsigned netid; // NetId: cache key and socket mark
	uid_t uid; // uid of the app that sent the DNS lookup		uid_t uid; // uid of the app that sent the DNS lookup
	pid_t pid; // pid of the app that sent the DNS lookup		pid_t pid; // pid of the app that sent the DNS lookup
	int nscount; // number of name srvers		int nscount; // number of name srvers
	uint16_t id; // current message id		uint16_t id; // current message id
	std::vector<std::string> search_domains; // domains to search		std::vector<std::string> search_domains{}; // domains to search
	sockaddr_union nsaddrs[MAXNS];		sockaddr_union nsaddrs[MAXNS];
	int nssocks[MAXNS]; // UDP sockets to nameservers		android::base::unique_fd nssocks[MAXNS]; // UDP sockets to nameservers
	unsigned ndots : 4; // threshold for initial abs. query		unsigned ndots : 4; // threshold for initial abs. query
	unsigned _mark; // If non-0 SET_MARK to _mark on all request sockets		unsigned _mark; // If non-0 SET_MARK to _mark on all request sockets
	int _vcsock; // TCP socket (but why not one per nameserver?)		android::base::unique_fd tcp_nssock; // TCP socket (but why not one per nameserver?)
	uint32_t _flags; // See RES_F_* defines below		uint32_t _flags = 0; // See RES_F_* defines below
	android::net::NetworkDnsEventReported* event;		android::net::NetworkDnsEventReported* event;
	uint32_t netcontext_flags;		uint32_t netcontext_flags;
	int tc_mode;		int tc_mode = 0;
			// clang-format on
	};		};

	// TODO: remove these legacy aliases		// TODO: remove these legacy aliases
	@@ -121,10 +136,6 @@ void _res_stats_set_sample(res_sample* sample, time_t now, int rcode, int rtt);

	/* End of stats related definitions */		/* End of stats related definitions */

	// Flags for res_state->_flags
	#define RES_F_VC 0x00000001 // socket is TCP
	#define RES_F_EDNS0ERR 0x00000004 // EDNS0 caused errors

	/*		/*
	* Error code extending h_errno codes defined in bionic/libc/include/netdb.h.		* Error code extending h_errno codes defined in bionic/libc/include/netdb.h.
	*		*
	@@ -146,7 +157,6 @@ int res_nquerydomain(res_state, const char, const char, int, int, uint8_t*, in
	int res_nmkquery(int op, const char* qname, int cl, int type, const uint8_t* data, int datalen,		int res_nmkquery(int op, const char* qname, int cl, int type, const uint8_t* data, int datalen,
	uint8_t* buf, int buflen, int netcontext_flags);		uint8_t* buf, int buflen, int netcontext_flags);
	int res_nsend(res_state, const uint8_t, int, uint8_t, int, int*, uint32_t);		int res_nsend(res_state, const uint8_t, int, uint8_t, int, int*, uint32_t);
	void res_nclose(res_state);
	int res_nopt(res_state, int, uint8_t*, int, int);		int res_nopt(res_state, int, uint8_t*, int, int);

	int getaddrinfo_numeric(const char* hostname, const char* servname, addrinfo hints,		int getaddrinfo_numeric(const char* hostname, const char* servname, addrinfo hints,