doc/designs/ddd/ddd-04-fd-nonblocking.c - third_party/openssl - Git at Google

 #include <sys/poll.h>
 #include <openssl/ssl.h>

 /*
  * Demo 4: Client — Client Creates FD — Nonblocking
  * ================================================
  *
  * This is an example of (part of) an application which uses libssl in an
  * asynchronous, nonblocking fashion. The client is responsible for creating the
  * socket and passing it to libssl. The functions show all interactions with
  * libssl the application makes, and would hypothetically be linked into a
  * larger application.
  */
 typedef struct app_conn_st {
     SSL *ssl;
     int fd;
     int rx_need_tx, tx_need_rx;
 } APP_CONN;

 /*
  * The application is initializing and wants an SSL_CTX which it will use for
  * some number of outgoing connections, which it creates in subsequent calls to
  * new_conn. The application may also call this function multiple times to
  * create multiple SSL_CTX.
  */
 SSL_CTX *create_ssl_ctx(void)
 {
     SSL_CTX *ctx;

 #ifdef USE_QUIC
     ctx = SSL_CTX_new(OSSL_QUIC_client_method());
 #else
     ctx = SSL_CTX_new(TLS_client_method());
 #endif
     if (ctx == NULL)
         return NULL;

     /* Enable trust chain verification. */
     SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);

     /* Load default root CA store. */
     if (SSL_CTX_set_default_verify_paths(ctx) == 0) {
         SSL_CTX_free(ctx);
         return NULL;
     }

     return ctx;
 }

 /*
  * The application wants to create a new outgoing connection using a given
  * SSL_CTX.
  *
  * hostname is a string like "openssl.org" used for certificate validation.
  */
 APP_CONN *new_conn(SSL_CTX *ctx, int fd, const char *bare_hostname)
 {
     APP_CONN *conn;
     SSL *ssl;
 #ifdef USE_QUIC
     static const unsigned char alpn[] = { 5, 'd', 'u', 'm', 'm', 'y' };
 #endif

     conn = calloc(1, sizeof(APP_CONN));
     if (conn == NULL)
         return NULL;

     ssl = conn->ssl = SSL_new(ctx);
     if (ssl == NULL) {
         free(conn);
         return NULL;
     }

     SSL_set_connect_state(ssl); /* cannot fail */

     if (SSL_set_fd(ssl, fd) <= 0) {
         SSL_free(ssl);
         free(conn);
         return NULL;
     }

     if (SSL_set1_host(ssl, bare_hostname) <= 0) {
         SSL_free(ssl);
         free(conn);
         return NULL;
     }

     if (SSL_set_tlsext_host_name(ssl, bare_hostname) <= 0) {
         SSL_free(ssl);
         free(conn);
         return NULL;
     }

 #ifdef USE_QUIC
     /* Configure ALPN, which is required for QUIC. */
     if (SSL_set_alpn_protos(ssl, alpn, sizeof(alpn))) {
         /* Note: SSL_set_alpn_protos returns 1 for failure. */
         SSL_free(ssl);
         free(conn);
         return NULL;
     }
 #endif

     conn->fd = fd;
     return conn;
 }

 /*
  * Non-blocking transmission.
  *
  * Returns -1 on error. Returns -2 if the function would block (corresponds to
  * EWOULDBLOCK).
  */
 int tx(APP_CONN *conn, const void *buf, int buf_len)
 {
     int rc, l;

     conn->tx_need_rx = 0;

     l = SSL_write(conn->ssl, buf, buf_len);
     if (l <= 0) {
         rc = SSL_get_error(conn->ssl, l);
         switch (rc) {
         case SSL_ERROR_WANT_READ:
             conn->tx_need_rx = 1;
         case SSL_ERROR_WANT_CONNECT:
         case SSL_ERROR_WANT_WRITE:
             return -2;
         default:
             return -1;
         }
     }

     return l;
 }

 /*
  * Non-blocking reception.
  *
  * Returns -1 on error. Returns -2 if the function would block (corresponds to
  * EWOULDBLOCK).
  */
 int rx(APP_CONN *conn, void *buf, int buf_len)
 {
     int rc, l;

     conn->rx_need_tx = 0;

     l = SSL_read(conn->ssl, buf, buf_len);
     if (l <= 0) {
         rc = SSL_get_error(conn->ssl, l);
         switch (rc) {
         case SSL_ERROR_WANT_WRITE:
             conn->rx_need_tx = 1;
         case SSL_ERROR_WANT_READ:
             return -2;
         default:
             return -1;
         }
     }

     return l;
 }

 /*
  * The application wants to know a fd it can poll on to determine when the
  * SSL state machine needs to be pumped.
  *
  * If the fd returned has:
  *
  *   POLLIN:    SSL_read *may* return data;
  *              if application does not want to read yet, it should call pump().
  *
  *   POLLOUT:   SSL_write *may* accept data
  *
  *   POLLERR:   An application should call pump() if it is not likely to call
  *              SSL_read or SSL_write soon.
  *
  */
 int get_conn_fd(APP_CONN *conn)
 {
     return conn->fd;
 }

 /*
  * These functions returns zero or more of:
  *
  *   POLLIN:    The SSL state machine is interested in socket readability events.
  *
  *   POLLOUT:   The SSL state machine is interested in socket writeability events.
  *
  *   POLLERR:   The SSL state machine is interested in socket error events.
  *
  * get_conn_pending_tx returns events which may cause SSL_write to make
  * progress and get_conn_pending_rx returns events which may cause SSL_read
  * to make progress.
  */
 int get_conn_pending_tx(APP_CONN *conn)
 {
 #ifdef USE_QUIC
     return (SSL_net_read_desired(conn->ssl) ? POLLIN : 0)
         | (SSL_net_write_desired(conn->ssl) ? POLLOUT : 0)
         | POLLERR;
 #else
     return (conn->tx_need_rx ? POLLIN : 0) | POLLOUT | POLLERR;
 #endif
 }

 int get_conn_pending_rx(APP_CONN *conn)
 {
     return get_conn_pending_tx(conn);
 }

 #ifdef USE_QUIC
 /*
  * Returns the number of milliseconds after which some call to libssl must be
  * made. Any call (SSL_read/SSL_write/SSL_pump) will do. Returns -1 if there is
  * no need for such a call. This may change after the next call
  * to libssl.
  */
 static inline int timeval_to_ms(const struct timeval *t);

 int get_conn_pump_timeout(APP_CONN *conn)
 {
     struct timeval tv;
     int is_infinite;

     if (!SSL_get_event_timeout(conn->ssl, &tv, &is_infinite))
         return -1;

     return is_infinite ? -1 : timeval_to_ms(&tv);
 }

 /*
  * Called to advance internals of libssl state machines without having to
  * perform an application-level read/write.
  */
 void pump(APP_CONN *conn)
 {
     SSL_handle_events(conn->ssl);
 }
 #endif

 /*
  * The application wants to close the connection and free bookkeeping
  * structures.
  */
 void teardown(APP_CONN *conn)
 {
     SSL_shutdown(conn->ssl);
     SSL_free(conn->ssl);
     free(conn);
 }

 /*
  * The application is shutting down and wants to free a previously
  * created SSL_CTX.
  */
 void teardown_ctx(SSL_CTX *ctx)
 {
     SSL_CTX_free(ctx);
 }

 /*
  * ============================================================================
  * Example driver for the above code. This is just to demonstrate that the code
  * works and is not intended to be representative of a real application.
  */
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/signal.h>
 #ifdef USE_QUIC
 #include <sys/time.h>
 #endif
 #include <netdb.h>
 #include <unistd.h>
 #include <fcntl.h>

 #ifdef USE_QUIC

 static inline void ms_to_timeval(struct timeval *t, int ms)
 {
     t->tv_sec = ms < 0 ? -1 : ms / 1000;
     t->tv_usec = ms < 0 ? 0 : (ms % 1000) * 1000;
 }

 static inline int timeval_to_ms(const struct timeval *t)
 {
     return t->tv_sec * 1000 + t->tv_usec / 1000;
 }

 #endif

 int main(int argc, char **argv)
 {
     int rc, fd = -1, res = 1;
     static char tx_msg[300];
     const char *tx_p = tx_msg;
     char rx_buf[2048];
     int l, tx_len;
 #ifdef USE_QUIC
     struct timeval timeout;
 #else
     int timeout = 2000 /* ms */;
 #endif
     APP_CONN *conn = NULL;
     struct addrinfo hints = { 0 }, *result = NULL;
     SSL_CTX *ctx = NULL;

 #ifdef USE_QUIC
     ms_to_timeval(&timeout, 2000);
 #endif

     if (argc < 3) {
         fprintf(stderr, "usage: %s host port\n", argv[0]);
         goto fail;
     }

     tx_len = snprintf(tx_msg, sizeof(tx_msg),
         "GET / HTTP/1.0\r\nHost: %s\r\n\r\n", argv[1]);

     ctx = create_ssl_ctx();
     if (ctx == NULL) {
         fprintf(stderr, "cannot create SSL context\n");
         goto fail;
     }

     hints.ai_family = AF_INET;
     hints.ai_socktype = SOCK_STREAM;
     hints.ai_flags = AI_PASSIVE;
     rc = getaddrinfo(argv[1], argv[2], &hints, &result);
     if (rc < 0) {
         fprintf(stderr, "cannot resolve\n");
         goto fail;
     }

     signal(SIGPIPE, SIG_IGN);

 #ifdef USE_QUIC
     fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 #else
     fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 #endif
     if (fd < 0) {
         fprintf(stderr, "cannot create socket\n");
         goto fail;
     }

     rc = connect(fd, result->ai_addr, result->ai_addrlen);
     if (rc < 0) {
         fprintf(stderr, "cannot connect\n");
         goto fail;
     }

     rc = fcntl(fd, F_SETFL, O_NONBLOCK);
     if (rc < 0) {
         fprintf(stderr, "cannot make socket nonblocking\n");
         goto fail;
     }

     conn = new_conn(ctx, fd, argv[1]);
     if (conn == NULL) {
         fprintf(stderr, "cannot establish connection\n");
         goto fail;
     }

     /* TX */
     while (tx_len != 0) {
         l = tx(conn, tx_p, tx_len);
         if (l > 0) {
             tx_p += l;
             tx_len -= l;
         } else if (l == -1) {
             fprintf(stderr, "tx error\n");
             goto fail;
         } else if (l == -2) {
 #ifdef USE_QUIC
             struct timeval start, now, deadline, t;
 #endif
             struct pollfd pfd = { 0 };

 #ifdef USE_QUIC
             ms_to_timeval(&t, get_conn_pump_timeout(conn));
             if (t.tv_sec < 0 || timercmp(&t, &timeout, >))
                 t = timeout;

             gettimeofday(&start, NULL);
             timeradd(&start, &timeout, &deadline);
 #endif

             pfd.fd = get_conn_fd(conn);
             pfd.events = get_conn_pending_tx(conn);
 #ifdef USE_QUIC
             if (poll(&pfd, 1, timeval_to_ms(&t)) == 0)
 #else
             if (poll(&pfd, 1, timeout) == 0)
 #endif
             {
 #ifdef USE_QUIC
                 pump(conn);

                 gettimeofday(&now, NULL);
                 if (timercmp(&now, &deadline, >=))
 #endif
                 {
                     fprintf(stderr, "tx timeout\n");
                     goto fail;
                 }
             }
         }
     }

     /* RX */
     for (;;) {
         l = rx(conn, rx_buf, sizeof(rx_buf));
         if (l > 0) {
             fwrite(rx_buf, 1, l, stdout);
         } else if (l == -1) {
             break;
         } else if (l == -2) {
 #ifdef USE_QUIC
             struct timeval start, now, deadline, t;
 #endif
             struct pollfd pfd = { 0 };

 #ifdef USE_QUIC
             ms_to_timeval(&t, get_conn_pump_timeout(conn));
             if (t.tv_sec < 0 || timercmp(&t, &timeout, >))
                 t = timeout;

             gettimeofday(&start, NULL);
             timeradd(&start, &timeout, &deadline);
 #endif

             pfd.fd = get_conn_fd(conn);
             pfd.events = get_conn_pending_rx(conn);
 #ifdef USE_QUIC
             if (poll(&pfd, 1, timeval_to_ms(&t)) == 0)
 #else
             if (poll(&pfd, 1, timeout) == 0)
 #endif
             {
 #ifdef USE_QUIC
                 pump(conn);
                 gettimeofday(&now, NULL);
                 if (timercmp(&now, &deadline, >=))
 #endif
                 {
                     fprintf(stderr, "rx timeout\n");
                     goto fail;
                 }
             }
         }
     }

     res = 0;
 fail:
     if (conn != NULL)
         teardown(conn);
     if (ctx != NULL)
         teardown_ctx(ctx);
     if (result != NULL)
         freeaddrinfo(result);
     return res;
 }
	#include <sys/poll.h>
	#include <openssl/ssl.h>

	/*
	* Demo 4: Client — Client Creates FD — Nonblocking
	* ================================================
	*
	* This is an example of (part of) an application which uses libssl in an
	* asynchronous, nonblocking fashion. The client is responsible for creating the
	* socket and passing it to libssl. The functions show all interactions with
	* libssl the application makes, and would hypothetically be linked into a
	* larger application.
	*/
	typedef struct app_conn_st {
	SSL *ssl;
	int fd;
	int rx_need_tx, tx_need_rx;
	} APP_CONN;

	/*
	* The application is initializing and wants an SSL_CTX which it will use for
	* some number of outgoing connections, which it creates in subsequent calls to
	* new_conn. The application may also call this function multiple times to
	* create multiple SSL_CTX.
	*/
	SSL_CTX *create_ssl_ctx(void)
	{
	SSL_CTX *ctx;

	#ifdef USE_QUIC
	ctx = SSL_CTX_new(OSSL_QUIC_client_method());
	#else
	ctx = SSL_CTX_new(TLS_client_method());
	#endif
	if (ctx == NULL)
	return NULL;

	/* Enable trust chain verification. */
	SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);

	/* Load default root CA store. */
	if (SSL_CTX_set_default_verify_paths(ctx) == 0) {
	SSL_CTX_free(ctx);
	return NULL;
	}

	return ctx;
	}

	/*
	* The application wants to create a new outgoing connection using a given
	* SSL_CTX.
	*
	* hostname is a string like "openssl.org" used for certificate validation.
	*/
	APP_CONN new_conn(SSL_CTX ctx, int fd, const char *bare_hostname)
	{
	APP_CONN *conn;
	SSL *ssl;
	#ifdef USE_QUIC
	static const unsigned char alpn[] = { 5, 'd', 'u', 'm', 'm', 'y' };
	#endif

	conn = calloc(1, sizeof(APP_CONN));
	if (conn == NULL)
	return NULL;

	ssl = conn->ssl = SSL_new(ctx);
	if (ssl == NULL) {
	free(conn);
	return NULL;
	}

	SSL_set_connect_state(ssl); /* cannot fail */

	if (SSL_set_fd(ssl, fd) <= 0) {
	SSL_free(ssl);
	free(conn);
	return NULL;
	}

	if (SSL_set1_host(ssl, bare_hostname) <= 0) {
	SSL_free(ssl);
	free(conn);
	return NULL;
	}

	if (SSL_set_tlsext_host_name(ssl, bare_hostname) <= 0) {
	SSL_free(ssl);
	free(conn);
	return NULL;
	}

	#ifdef USE_QUIC
	/* Configure ALPN, which is required for QUIC. */
	if (SSL_set_alpn_protos(ssl, alpn, sizeof(alpn))) {
	/* Note: SSL_set_alpn_protos returns 1 for failure. */
	SSL_free(ssl);
	free(conn);
	return NULL;
	}
	#endif

	conn->fd = fd;
	return conn;
	}

	/*
	* Non-blocking transmission.
	*
	* Returns -1 on error. Returns -2 if the function would block (corresponds to
	* EWOULDBLOCK).
	*/
	int tx(APP_CONN conn, const void buf, int buf_len)
	{
	int rc, l;

	conn->tx_need_rx = 0;

	l = SSL_write(conn->ssl, buf, buf_len);
	if (l <= 0) {
	rc = SSL_get_error(conn->ssl, l);
	switch (rc) {
	case SSL_ERROR_WANT_READ:
	conn->tx_need_rx = 1;
	case SSL_ERROR_WANT_CONNECT:
	case SSL_ERROR_WANT_WRITE:
	return -2;
	default:
	return -1;
	}
	}

	return l;
	}

	/*
	* Non-blocking reception.
	*
	* Returns -1 on error. Returns -2 if the function would block (corresponds to
	* EWOULDBLOCK).
	*/
	int rx(APP_CONN conn, void buf, int buf_len)
	{
	int rc, l;

	conn->rx_need_tx = 0;

	l = SSL_read(conn->ssl, buf, buf_len);
	if (l <= 0) {
	rc = SSL_get_error(conn->ssl, l);
	switch (rc) {
	case SSL_ERROR_WANT_WRITE:
	conn->rx_need_tx = 1;
	case SSL_ERROR_WANT_READ:
	return -2;
	default:
	return -1;
	}
	}

	return l;
	}

	/*
	* The application wants to know a fd it can poll on to determine when the
	* SSL state machine needs to be pumped.
	*
	* If the fd returned has:
	*
	* POLLIN: SSL_read may return data;
	* if application does not want to read yet, it should call pump().
	*
	* POLLOUT: SSL_write may accept data
	*
	* POLLERR: An application should call pump() if it is not likely to call
	* SSL_read or SSL_write soon.
	*
	*/
	int get_conn_fd(APP_CONN *conn)
	{
	return conn->fd;
	}

	/*
	* These functions returns zero or more of:
	*
	* POLLIN: The SSL state machine is interested in socket readability events.
	*
	* POLLOUT: The SSL state machine is interested in socket writeability events.
	*
	* POLLERR: The SSL state machine is interested in socket error events.
	*
	* get_conn_pending_tx returns events which may cause SSL_write to make
	* progress and get_conn_pending_rx returns events which may cause SSL_read
	* to make progress.
	*/
	int get_conn_pending_tx(APP_CONN *conn)
	{
	#ifdef USE_QUIC
	return (SSL_net_read_desired(conn->ssl) ? POLLIN : 0)
	\| (SSL_net_write_desired(conn->ssl) ? POLLOUT : 0)
	\| POLLERR;
	#else
	return (conn->tx_need_rx ? POLLIN : 0) \| POLLOUT \| POLLERR;
	#endif
	}

	int get_conn_pending_rx(APP_CONN *conn)
	{
	return get_conn_pending_tx(conn);
	}

	#ifdef USE_QUIC
	/*
	* Returns the number of milliseconds after which some call to libssl must be
	* made. Any call (SSL_read/SSL_write/SSL_pump) will do. Returns -1 if there is
	* no need for such a call. This may change after the next call
	* to libssl.
	*/
	static inline int timeval_to_ms(const struct timeval *t);

	int get_conn_pump_timeout(APP_CONN *conn)
	{
	struct timeval tv;
	int is_infinite;

	if (!SSL_get_event_timeout(conn->ssl, &tv, &is_infinite))
	return -1;

	return is_infinite ? -1 : timeval_to_ms(&tv);
	}

	/*
	* Called to advance internals of libssl state machines without having to
	* perform an application-level read/write.
	*/
	void pump(APP_CONN *conn)
	{
	SSL_handle_events(conn->ssl);
	}
	#endif

	/*
	* The application wants to close the connection and free bookkeeping
	* structures.
	*/
	void teardown(APP_CONN *conn)
	{
	SSL_shutdown(conn->ssl);
	SSL_free(conn->ssl);
	free(conn);
	}

	/*
	* The application is shutting down and wants to free a previously
	* created SSL_CTX.
	*/
	void teardown_ctx(SSL_CTX *ctx)
	{
	SSL_CTX_free(ctx);
	}

	/*
	* ============================================================================
	* Example driver for the above code. This is just to demonstrate that the code
	* works and is not intended to be representative of a real application.
	*/
	#include <sys/types.h>
	#include <sys/socket.h>
	#include <sys/signal.h>
	#ifdef USE_QUIC
	#include <sys/time.h>
	#endif
	#include <netdb.h>
	#include <unistd.h>
	#include <fcntl.h>

	#ifdef USE_QUIC

	static inline void ms_to_timeval(struct timeval *t, int ms)
	{
	t->tv_sec = ms < 0 ? -1 : ms / 1000;
	t->tv_usec = ms < 0 ? 0 : (ms % 1000) * 1000;
	}

	static inline int timeval_to_ms(const struct timeval *t)
	{
	return t->tv_sec * 1000 + t->tv_usec / 1000;
	}

	#endif

	int main(int argc, char **argv)
	{
	int rc, fd = -1, res = 1;
	static char tx_msg[300];
	const char *tx_p = tx_msg;
	char rx_buf[2048];
	int l, tx_len;
	#ifdef USE_QUIC
	struct timeval timeout;
	#else
	int timeout = 2000 /* ms */;
	#endif
	APP_CONN *conn = NULL;
	struct addrinfo hints = { 0 }, *result = NULL;
	SSL_CTX *ctx = NULL;

	#ifdef USE_QUIC
	ms_to_timeval(&timeout, 2000);
	#endif

	if (argc < 3) {
	fprintf(stderr, "usage: %s host port\n", argv[0]);
	goto fail;
	}

	tx_len = snprintf(tx_msg, sizeof(tx_msg),
	"GET / HTTP/1.0\r\nHost: %s\r\n\r\n", argv[1]);

	ctx = create_ssl_ctx();
	if (ctx == NULL) {
	fprintf(stderr, "cannot create SSL context\n");
	goto fail;
	}

	hints.ai_family = AF_INET;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_flags = AI_PASSIVE;
	rc = getaddrinfo(argv[1], argv[2], &hints, &result);
	if (rc < 0) {
	fprintf(stderr, "cannot resolve\n");
	goto fail;
	}

	signal(SIGPIPE, SIG_IGN);

	#ifdef USE_QUIC
	fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	#else
	fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	#endif
	if (fd < 0) {
	fprintf(stderr, "cannot create socket\n");
	goto fail;
	}

	rc = connect(fd, result->ai_addr, result->ai_addrlen);
	if (rc < 0) {
	fprintf(stderr, "cannot connect\n");
	goto fail;
	}

	rc = fcntl(fd, F_SETFL, O_NONBLOCK);
	if (rc < 0) {
	fprintf(stderr, "cannot make socket nonblocking\n");
	goto fail;
	}

	conn = new_conn(ctx, fd, argv[1]);
	if (conn == NULL) {
	fprintf(stderr, "cannot establish connection\n");
	goto fail;
	}

	/* TX */
	while (tx_len != 0) {
	l = tx(conn, tx_p, tx_len);
	if (l > 0) {
	tx_p += l;
	tx_len -= l;
	} else if (l == -1) {
	fprintf(stderr, "tx error\n");
	goto fail;
	} else if (l == -2) {
	#ifdef USE_QUIC
	struct timeval start, now, deadline, t;
	#endif
	struct pollfd pfd = { 0 };

	#ifdef USE_QUIC
	ms_to_timeval(&t, get_conn_pump_timeout(conn));
	if (t.tv_sec < 0 \|\| timercmp(&t, &timeout, >))
	t = timeout;

	gettimeofday(&start, NULL);
	timeradd(&start, &timeout, &deadline);
	#endif

	pfd.fd = get_conn_fd(conn);
	pfd.events = get_conn_pending_tx(conn);
	#ifdef USE_QUIC
	if (poll(&pfd, 1, timeval_to_ms(&t)) == 0)
	#else
	if (poll(&pfd, 1, timeout) == 0)
	#endif
	{
	#ifdef USE_QUIC
	pump(conn);

	gettimeofday(&now, NULL);
	if (timercmp(&now, &deadline, >=))
	#endif
	{
	fprintf(stderr, "tx timeout\n");
	goto fail;
	}
	}
	}
	}

	/* RX */
	for (;;) {
	l = rx(conn, rx_buf, sizeof(rx_buf));
	if (l > 0) {
	fwrite(rx_buf, 1, l, stdout);
	} else if (l == -1) {
	break;
	} else if (l == -2) {
	#ifdef USE_QUIC
	struct timeval start, now, deadline, t;
	#endif
	struct pollfd pfd = { 0 };

	#ifdef USE_QUIC
	ms_to_timeval(&t, get_conn_pump_timeout(conn));
	if (t.tv_sec < 0 \|\| timercmp(&t, &timeout, >))
	t = timeout;

	gettimeofday(&start, NULL);
	timeradd(&start, &timeout, &deadline);
	#endif

	pfd.fd = get_conn_fd(conn);
	pfd.events = get_conn_pending_rx(conn);
	#ifdef USE_QUIC
	if (poll(&pfd, 1, timeval_to_ms(&t)) == 0)
	#else
	if (poll(&pfd, 1, timeout) == 0)
	#endif
	{
	#ifdef USE_QUIC
	pump(conn);
	gettimeofday(&now, NULL);
	if (timercmp(&now, &deadline, >=))
	#endif
	{
	fprintf(stderr, "rx timeout\n");
	goto fail;
	}
	}
	}
	}

	res = 0;
	fail:
	if (conn != NULL)
	teardown(conn);
	if (ctx != NULL)
	teardown_ctx(ctx);
	if (result != NULL)
	freeaddrinfo(result);
	return res;
	}