Fix: Connect timeout arithmetic in inet/inet6 (v4)

[lttng-tools.git] / src / common / sessiond-comm / inet6.c

diff --git a/src/common/sessiond-comm/inet6.c b/src/common/sessiond-comm/inet6.c
index 8d883740478f0c0cfca365f2334daed6a7669ba5..03b6627d1dce45188d28d81d234cb2c208c062eb 100644 (file)
--- a/src/common/sessiond-comm/inet6.c
+++ b/src/common/sessiond-comm/inet6.c
@@ -15,7 +15,7 @@
  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <assert.h>
 #include <limits.h>
 #include <stdio.h>
@@ -25,11 +25,17 @@
 #include <sys/types.h>
 #include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
+#include <common/compat/time.h>
+#include <poll.h>
 
 #include <common/common.h>
+#include <common/time.h>
 
 #include "inet6.h"
 
+#define RECONNECT_DELAY        200     /* ms */
+
 /*
  * INET protocol operations.
  */
@@ -50,6 +56,7 @@ LTTNG_HIDDEN
 int lttcomm_create_inet6_sock(struct lttcomm_sock *sock, int type, int proto)
 {
        int val = 1, ret;
+       unsigned long timeout;
 
        /* Create server socket */
        if ((sock->fd = socket(PF_INET6, type, proto)) < 0) {
@@ -67,6 +74,17 @@ int lttcomm_create_inet6_sock(struct lttcomm_sock *sock, int type, int proto)
                PERROR("setsockopt inet6");
                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;
 
@@ -80,15 +98,126 @@ error:
 LTTNG_HIDDEN
 int lttcomm_bind_inet6_sock(struct lttcomm_sock *sock)
 {
-       int ret;
+       return bind(sock->fd,
+                       (const struct sockaddr *) &sock->sockaddr.addr.sin6,
+                       sizeof(sock->sockaddr.addr.sin6));
+}
 
-       ret = bind(sock->fd, &sock->sockaddr.addr.sin6,
+static
+int connect_no_timeout(struct lttcomm_sock *sock)
+{
+       return connect(sock->fd, (struct sockaddr *) &sock->sockaddr.addr.sin6,
                        sizeof(sock->sockaddr.addr.sin6));
-       if (ret < 0) {
-               PERROR("bind inet6");
+}
+
+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;
+       unsigned long diff_ms;
+
+       ret = fcntl(sock->fd, F_GETFL, 0);
+       if (ret == -1) {
+               PERROR("fcntl");
+               return -1;
        }
+       flags = ret;
 
-       return ret;
+       /* Set socket to nonblock */
+       ret = fcntl(sock->fd, F_SETFL, flags | O_NONBLOCK);
+       if (ret == -1) {
+               PERROR("fcntl");
+               return -1;
+       }
+
+       ret = lttng_clock_gettime(CLOCK_MONOTONIC, &orig_time);
+       if (ret == -1) {
+               PERROR("clock_gettime");
+               return -1;
+       }
+
+       connect_ret = connect(sock->fd,
+               (struct sockaddr *) &sock->sockaddr.addr.sin6,
+               sizeof(sock->sockaddr.addr.sin6));
+       if (connect_ret == -1 && errno != EAGAIN
+                       && errno != EWOULDBLOCK
+                       && errno != EINPROGRESS) {
+               goto error;
+       } else if (!connect_ret) {
+               /* Connect succeeded */
+               goto success;
+       }
+
+       DBG("Asynchronous connect for sock %d, performing polling with"
+                       " timeout: %lums", sock->fd, timeout);
+
+       /*
+        * 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) {
+                               PERROR("getsockopt");
+                               goto error;
+                       }
+                       if (!optval) {
+                               connect_ret = 0;
+                               goto success;
+                       } else {
+                               /* Get actual connect() errno from opt_val */
+                               errno = optval;
+                               goto error;
+                       }
+               }
+               /* ret == 0: timeout */
+               ret = lttng_clock_gettime(CLOCK_MONOTONIC, &cur_time);
+               if (ret == -1) {
+                       PERROR("clock_gettime");
+                       connect_ret = ret;
+                       goto error;
+               }
+               if (timespec_to_ms(timespec_abs_diff(cur_time, orig_time), &diff_ms) < 0) {
+                       ERR("timespec_to_ms input overflows milliseconds output");
+                       connect_ret = -1;
+                       goto error;
+               }
+       } while (diff_ms < 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;
 }
 
 /*
@@ -99,8 +228,11 @@ int lttcomm_connect_inet6_sock(struct lttcomm_sock *sock)
 {
        int ret, closeret;
 
-       ret = connect(sock->fd, (struct sockaddr *) &sock->sockaddr.addr.sin6,
-                       sizeof(sock->sockaddr.addr.sin6));
+       if (lttcomm_get_network_timeout()) {
+               ret = connect_with_timeout(sock);
+       } else {
+               ret = connect_no_timeout(sock);
+       }
        if (ret < 0) {
                PERROR("connect inet6");
                goto error_connect;
@@ -219,6 +351,9 @@ ssize_t lttcomm_recvmsg_inet6_sock(struct lttcomm_sock *sock, void *buf,
                len_last = iov[0].iov_len;
                ret = recvmsg(sock->fd, &msg, flags);
                if (ret > 0) {
+                       if (flags & MSG_DONTWAIT) {
+                               goto end;
+                       }
                        iov[0].iov_base += ret;
                        iov[0].iov_len -= ret;
                        assert(ret <= len_last);
@@ -230,7 +365,7 @@ ssize_t lttcomm_recvmsg_inet6_sock(struct lttcomm_sock *sock, void *buf,
                ret = len;
        }
        /* Else ret = 0 meaning an orderly shutdown. */
-
+end:
        return ret;
 }
 
@@ -240,7 +375,7 @@ ssize_t lttcomm_recvmsg_inet6_sock(struct lttcomm_sock *sock, void *buf,
  * Return the size of sent data.
  */
 LTTNG_HIDDEN
-ssize_t lttcomm_sendmsg_inet6_sock(struct lttcomm_sock *sock, void *buf,
+ssize_t lttcomm_sendmsg_inet6_sock(struct lttcomm_sock *sock, const void *buf,
                size_t len, int flags)
 {
        struct msghdr msg;
@@ -249,7 +384,7 @@ ssize_t lttcomm_sendmsg_inet6_sock(struct lttcomm_sock *sock, void *buf,
 
        memset(&msg, 0, sizeof(msg));
 
-       iov[0].iov_base = buf;
+       iov[0].iov_base = (void *) buf;
        iov[0].iov_len = len;
        msg.msg_iov = iov;
        msg.msg_iovlen = 1;