osmo_io: Use poll/select to notify socket connection at osmo_io_uring.c
In order to receive a connect notification from SCTP socket,
poll/select event must be used instead of a write notification via
io_uring completion event.
Once the connect notification has been received, subsequent write
notifications via io_uring are used.
Change-Id: I4eca9ea72beb0d6ea4d44cce81ed620033f07270
Related: OS#5751
diff --git a/src/core/osmo_io_uring.c b/src/core/osmo_io_uring.c
index aa9df85..af1c790 100644
--- a/src/core/osmo_io_uring.c
+++ b/src/core/osmo_io_uring.c
@@ -324,6 +324,11 @@
}
io_uring_submit(&g_ring.ring);
+ if (IOFD_FLAG_ISSET(iofd, IOFD_FLAG_NOTIFY_CONNECTED)) {
+ osmo_fd_unregister(&iofd->u.uring.connect_ofd);
+ IOFD_FLAG_UNSET(iofd, IOFD_FLAG_NOTIFY_CONNECTED);
+ }
+
return 0;
}
@@ -334,6 +339,10 @@
if (iofd->u.uring.write_msghdr)
return;
+ /* This function is called again, once the socket is connected. */
+ if (IOFD_FLAG_ISSET(iofd, IOFD_FLAG_NOTIFY_CONNECTED))
+ return;
+
if (osmo_iofd_txqueue_len(iofd) > 0)
iofd_uring_submit_tx(iofd);
else if (iofd->mode == OSMO_IO_FD_MODE_READ_WRITE) {
@@ -379,6 +388,10 @@
if (iofd->u.uring.read_msghdr)
return;
+ /* This function is called again, once the socket is connected. */
+ if (IOFD_FLAG_ISSET(iofd, IOFD_FLAG_NOTIFY_CONNECTED))
+ return;
+
switch (iofd->mode) {
case OSMO_IO_FD_MODE_READ_WRITE:
iofd_uring_submit_recv(iofd, IOFD_ACT_READ);
@@ -407,6 +420,66 @@
return close(iofd->fd);
}
+/* called via osmocom poll/select main handling once outbound non-blocking connect() completes */
+static int iofd_uring_connected_cb(struct osmo_fd *ofd, unsigned int what)
+{
+ struct osmo_io_fd *iofd = ofd->data;
+
+ LOGPIO(iofd, LOGL_DEBUG, "Socket connected or failed.");
+
+ if (!(what & OSMO_FD_WRITE))
+ return 0;
+
+ /* Unregister from poll/select handling. */
+ osmo_fd_unregister(ofd);
+ IOFD_FLAG_UNSET(iofd, IOFD_FLAG_NOTIFY_CONNECTED);
+
+ /* Notify the application about this via a zero-length write completion call-back. */
+ IOFD_FLAG_SET(iofd, IOFD_FLAG_IN_CALLBACK);
+ switch (iofd->mode) {
+ case OSMO_IO_FD_MODE_READ_WRITE:
+ iofd->io_ops.write_cb(iofd, 0, NULL);
+ break;
+ case OSMO_IO_FD_MODE_RECVFROM_SENDTO:
+ iofd->io_ops.sendto_cb(iofd, 0, NULL, NULL);
+ break;
+ case OSMO_IO_FD_MODE_RECVMSG_SENDMSG:
+ iofd->io_ops.sendmsg_cb(iofd, 0, NULL);
+ break;
+ }
+ IOFD_FLAG_UNSET(iofd, IOFD_FLAG_IN_CALLBACK);
+
+ /* If write/read notifications are pending, enable it now. */
+ if (iofd->u.uring.write_enabled && !IOFD_FLAG_ISSET(iofd, IOFD_FLAG_CLOSED))
+ iofd_uring_write_enable(iofd);
+ if (iofd->u.uring.read_enabled && !IOFD_FLAG_ISSET(iofd, IOFD_FLAG_CLOSED))
+ iofd_uring_read_enable(iofd);
+
+ if (IOFD_FLAG_ISSET(iofd, IOFD_FLAG_TO_FREE) && !iofd->u.uring.read_msghdr && !iofd->u.uring.write_msghdr)
+ talloc_free(iofd);
+ return 0;
+}
+
+static void iofd_uring_notify_connected(struct osmo_io_fd *iofd)
+{
+ if (iofd->mode == OSMO_IO_FD_MODE_RECVMSG_SENDMSG) {
+ /* Don't call this function after enabling read or write. */
+ OSMO_ASSERT(!iofd->u.uring.write_enabled && !iofd->u.uring.read_enabled);
+
+ /* Use a temporary osmo_fd which we can use to notify us once the connection is established
+ * or failed (indicated by FD becoming writable).
+ * This is needed as (at least for SCTP sockets) one cannot submit a zero-length writev/sendmsg
+ * in order to get notification when the socekt is writable.*/
+ if (!IOFD_FLAG_ISSET(iofd, IOFD_FLAG_NOTIFY_CONNECTED)) {
+ osmo_fd_setup(&iofd->u.uring.connect_ofd, iofd->fd, OSMO_FD_WRITE,
+ iofd_uring_connected_cb, iofd, 0);
+ osmo_fd_register(&iofd->u.uring.connect_ofd);
+ IOFD_FLAG_SET(iofd, IOFD_FLAG_NOTIFY_CONNECTED);
+ }
+ } else
+ iofd_uring_write_enable(iofd);
+}
+
const struct iofd_backend_ops iofd_uring_ops = {
.register_fd = iofd_uring_register,
.unregister_fd = iofd_uring_unregister,
@@ -415,7 +488,7 @@
.write_disable = iofd_uring_write_disable,
.read_enable = iofd_uring_read_enable,
.read_disable = iofd_uring_read_disable,
- .notify_connected = iofd_uring_write_enable,
+ .notify_connected = iofd_uring_notify_connected,
};
#endif /* defined(__linux__) */