inet/inet6 sockets: apply timeout

[lttng-tools.git] / src / common / sessiond-comm / inet.c

diff --git a/src/common/sessiond-comm/inet.c b/src/common/sessiond-comm/inet.c
index b2bd65d9029672efb47a4469ef3632b30a649740..eb0c4fde3f6972de1d846020f10aa58a0deaad35 100644 (file)
--- a/src/common/sessiond-comm/inet.c
+++ b/src/common/sessiond-comm/inet.c
@@ -25,11 +25,18 @@
 #include <sys/types.h>
 #include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
+#include <time.h>
+#include <poll.h>
 
 #include <common/common.h>
 
 #include "inet.h"
 
+#define MSEC_PER_SEC   1000
+#define NSEC_PER_MSEC  1000000
+#define RECONNECT_DELAY        200     /* ms */
+
 /*
  * INET protocol operations.
  */
@@ -50,6 +57,7 @@ LTTNG_HIDDEN
 int lttcomm_create_inet_sock(struct lttcomm_sock *sock, int type, int proto)
 {
        int val = 1, ret;
+       unsigned long timeout;
 
        /* Create server socket */
        if ((sock->fd = socket(PF_INET, type, proto)) < 0) {
@@ -67,6 +75,17 @@ int lttcomm_create_inet_sock(struct lttcomm_sock *sock, int type, int proto)
                PERROR("setsockopt inet");
                goto error;
        }
+       timeout = lttcomm_get_network_timeout();
+       if (timeout) {
+               ret = lttcomm_setsockopt_rcv_timeout(sock->fd, timeout);
+               if (ret) {
+                       goto error;
+               }
+               ret = lttcomm_setsockopt_snd_timeout(sock->fd, timeout);
+               if (ret) {
+                       goto error;
+               }
+       }
 
        return 0;
 
@@ -91,6 +110,130 @@ int lttcomm_bind_inet_sock(struct lttcomm_sock *sock)
        return ret;
 }
 
+static
+int connect_no_timeout(struct lttcomm_sock *sock)
+{
+       return connect(sock->fd, (struct sockaddr *) &sock->sockaddr.addr.sin,
+                       sizeof(sock->sockaddr.addr.sin));
+}
+
+/*
+ * Return time_a - time_b  in milliseconds.
+ */
+static
+unsigned long time_diff_ms(struct timespec *time_a,
+               struct timespec *time_b)
+{
+       time_t sec_diff;
+       long nsec_diff;
+       unsigned long result_ms;
+
+       sec_diff = time_a->tv_sec - time_b->tv_sec;
+       nsec_diff = time_a->tv_nsec - time_b->tv_nsec;
+
+       result_ms = sec_diff * MSEC_PER_SEC;
+       result_ms += nsec_diff / NSEC_PER_MSEC;
+       return result_ms;
+}
+
+static
+int connect_with_timeout(struct lttcomm_sock *sock)
+{
+       unsigned long timeout = lttcomm_get_network_timeout();
+       int ret, flags, connect_ret;
+       struct timespec orig_time, cur_time;
+
+       ret = fcntl(sock->fd, F_GETFL, 0);
+       if (ret == -1) {
+               PERROR("fcntl");
+               return -1;
+       }
+       flags = ret;
+
+       /* Set socket to nonblock */
+       ret = fcntl(sock->fd, F_SETFL, flags | O_NONBLOCK);
+       if (ret == -1) {
+               PERROR("fcntl");
+               return -1;
+       }
+
+       ret = clock_gettime(CLOCK_MONOTONIC, &orig_time);
+       if (ret == -1) {
+               PERROR("clock_gettime");
+               return -1;
+       }
+
+       connect_ret = connect(sock->fd,
+               (struct sockaddr *) &sock->sockaddr.addr.sin,
+               sizeof(sock->sockaddr.addr.sin));
+       if (connect_ret == -1 && errno != EAGAIN
+                       && errno != EWOULDBLOCK
+                       && errno != EINPROGRESS) {
+               goto error;
+       } else if (!connect_ret) {
+               /* Connect succeeded */
+               goto success;
+       }
+
+       /*
+        * Perform poll loop following EINPROGRESS recommendation from
+        * connect(2) man page.
+        */
+       do {
+               struct pollfd fds;
+
+               fds.fd = sock->fd;
+               fds.events = POLLOUT;
+               fds.revents = 0;
+               ret = poll(&fds, 1, RECONNECT_DELAY);
+               if (ret < 0) {
+                       goto error;
+               } else if (ret > 0) {
+                       int optval;
+                       socklen_t optval_len = sizeof(optval);
+
+                       if (!(fds.revents & POLLOUT)) {
+                               /* Either hup or error */
+                               errno = EPIPE;
+                               goto error;
+                       }
+                       /* got something */
+                       ret = getsockopt(sock->fd, SOL_SOCKET,
+                               SO_ERROR, &optval, &optval_len);
+                       if (ret) {
+                               goto error;
+                       }
+                       if (!optval) {
+                               connect_ret = 0;
+                               goto success;
+                       } else {
+                               goto error;
+                       }
+               }
+               /* ret == 0: timeout */
+               ret = clock_gettime(CLOCK_MONOTONIC, &cur_time);
+               if (ret == -1) {
+                       PERROR("clock_gettime");
+                       connect_ret = ret;
+                       goto error;
+               }
+       } while (time_diff_ms(&cur_time, &orig_time) < timeout);
+
+       /* Timeout */
+       errno = ETIMEDOUT;
+       connect_ret = -1;
+
+success:
+       /* Restore initial flags */
+       ret = fcntl(sock->fd, F_SETFL, flags);
+       if (ret == -1) {
+               PERROR("fcntl");
+               /* Continue anyway */
+       }
+error:
+       return connect_ret;
+}
+
 /*
  * Connect PF_INET socket.
  */
@@ -99,8 +242,11 @@ int lttcomm_connect_inet_sock(struct lttcomm_sock *sock)
 {
        int ret, closeret;
 
-       ret = connect(sock->fd, (struct sockaddr *) &sock->sockaddr.addr.sin,
-                       sizeof(sock->sockaddr.addr.sin));
+       if (lttcomm_get_network_timeout()) {
+               ret = connect_with_timeout(sock);
+       } else {
+               ret = connect_no_timeout(sock);
+       }
        if (ret < 0) {
                PERROR("connect");
                goto error_connect;