dnstap io output performs nonblocking connect.

diff --git a/dnstap/dtstream.c b/dnstap/dtstream.c
index 2e2de641ab634de5d30d9defcf57265b8b001972..4ebf9f21e9e36c0233ea72bec1e80a8d0effe4dd 100644 (file)
--- a/dnstap/dtstream.c
+++ b/dnstap/dtstream.c
@@ -316,6 +316,49 @@ static void dtio_close_output(struct dt_io_thread* dtio)
        dtio->fd = -1;
 }
 
+/** check for pending nonblocking connect errors,
+ * returns 1 if it is okay. -1 on error (close it), 0 to try later */
+static int dtio_check_nb_connect(struct dt_io_thread* dtio)
+{
+       int error = 0;
+       socklen_t len = (socklen_t)sizeof(error);
+       if(!dtio->check_nb_connect)
+               return 1; /* everything okay */
+       if(getsockopt(dtio->fd, SOL_SOCKET, SO_ERROR, (void*)&error,
+               &len) < 0) {
+#ifndef USE_WINSOCK
+               error = errno; /* on solaris errno is error */
+#else
+               error = WSAGetLastError();
+#endif
+       }
+#ifndef USE_WINSOCK
+#if defined(EINPROGRESS) && defined(EWOULDBLOCK)
+       if(error == EINPROGRESS || error == EWOULDBLOCK)
+               return 0; /* try again later */
+#endif
+#else
+       if(error == WSAEINPROGRESS) {
+               return 0; /* try again later */
+       } else if(error == WSAEWOULDBLOCK) {
+               ub_winsock_tcp_wouldblock(dtio->event, UB_EV_WRITE);
+               return 0; /* try again later */
+       }
+#endif
+       if(error != 0) {
+#ifndef USE_WINSOCK
+               log_err("dnstap io: failed to connect: %s", strerror(error));
+#else
+               log_err("dnstap io: failed to connect: %s",
+                       wsa_strerror(error));
+#endif
+               return -1; /* error, close it */
+       }
+
+       dtio->check_nb_connect = 0;
+       return 1; /* everything okay */
+}
+
 /** write buffer to output.
  * returns number of bytes written, 0 if nothing happened,
  * try again later, or -1 if the channel is to be closed. */
@@ -325,6 +368,14 @@ static int dtio_write_buf(struct dt_io_thread* dtio, uint8_t* buf,
        ssize_t ret;
        if(dtio->fd == -1)
                return -1;
+       if(dtio->check_nb_connect) {
+               int connect_err = dtio_check_nb_connect(dtio);
+               if(connect_err == -1) {
+                       return -1;
+               } else if(connect_err == 0) {
+                       return 0;
+               }
+       }
        ret = send(dtio->fd, buf, len, 0);
        if(ret == -1) {
 #ifndef USE_WINSOCK
@@ -354,6 +405,17 @@ static int dtio_write_with_writev(struct dt_io_thread* dtio)
        uint32_t sendlen = htonl(dtio->cur_msg_len);
        struct iovec iov[2];
        ssize_t r;
+       if(dtio->check_nb_connect) {
+               int connect_err = dtio_check_nb_connect(dtio);
+               if(connect_err == -1) {
+                       /* close the channel */
+                       dtio_del_output_event(dtio);
+                       dtio_close_output(dtio);
+                       return 0;
+               } else if(connect_err == 0) {
+                       return 0;
+               }
+       }
        iov[0].iov_base = ((uint8_t*)&sendlen)+dtio->cur_msg_len_done;
        iov[0].iov_len = sizeof(sendlen)-dtio->cur_msg_len_done;
        iov[1].iov_base = dtio->cur_msg;
@@ -802,6 +864,7 @@ static void dtio_open_output(struct dt_io_thread* dtio)
        s.sun_family = AF_LOCAL;
        /* length is 92-108, 104 on FreeBSD */
         (void)strlcpy(s.sun_path, dtio->socket_path, sizeof(s.sun_path));
+       fd_set_nonblock(dtio->fd);
        if(connect(dtio->fd, (struct sockaddr*)&s, (socklen_t)sizeof(s))
                == -1) {
 #ifndef USE_WINSOCK
@@ -818,7 +881,7 @@ static void dtio_open_output(struct dt_io_thread* dtio)
                dtio->fd = -1;
                return;
        }
-       fd_set_nonblock(dtio->fd);
+       dtio->check_nb_connect = 1;
 
        /* the EV_READ is to catch channel close, write to write packets */
        ev = ub_event_new(dtio->event_base, dtio->fd,

diff --git a/dnstap/dtstream.h b/dnstap/dtstream.h
index 94c6b698d2c4660509640b493e9a63a5c0d08b89..7641ffbd6db6e6b34cfb82e82343a766d2eb107a 100644 (file)
--- a/dnstap/dtstream.h
+++ b/dnstap/dtstream.h
@@ -101,6 +101,8 @@ struct dt_io_thread {
        void* event;
        /** the event is added */
        int event_added;
+       /** check for nonblocking connect errors on fd */
+       int check_nb_connect;
        /** the buffer that currently getting written, or NULL if no
         * (partial) message written now */
        void* cur_msg;