diff --git a/VERSION b/VERSION
index 485b77cb..fd879717 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-B1-30-g67ddb70932+1
\ No newline at end of file
+B1-31-gf4ad730cc4+1
\ No newline at end of file
diff --git a/porthole/include/porthole/client.h b/porthole/include/porthole/client.h
new file mode 100644
index 00000000..8435a0b8
--- /dev/null
+++ b/porthole/include/porthole/client.h
@@ -0,0 +1,96 @@
+/*
+Looking Glass - KVM FrameRelay (KVMFR) Client
+Copyright (C) 2017-2019 Geoffrey McRae <geoff@hostfission.com>
+https://looking-glass.hostfission.com
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; either version 2 of the License, or (at your option) any later
+version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef struct PortholeClient *PortholeClient;
+
+typedef struct
+{
+  unsigned int   size;
+  void         * data;
+}
+PortholeSegment;
+
+typedef struct
+{
+  uint32_t        id;
+  unsigned int    size;
+  unsigned int    num_segments;
+  PortholeSegment segments[0];
+}
+PortholeMap;
+
+/**
+ * Memory map event callback.
+ *
+ * @param type The type ID provided by the guest
+ * @param map  The new mapping
+ *
+ * @note this is called from the socket thread
+ */
+typedef void (*PortholeMapEvent)(uint32_t type, PortholeMap * map);
+
+/**
+ * Memory unmap event callback.
+ *
+ * @param id The id of the mapping that has been unmapped by the guest
+ *
+ * @note this is called from the socket thread
+ */
+typedef void (*PortholeUnmapEvent)(uint32_t id);
+
+/**
+ * Unexpected client disconnection event.
+ *
+ * When this occurs all mappings become invalid and should no longer be used.
+ *
+ * @note this is called from the socket thread
+ */
+typedef void (*PortholeDisconEvent)();
+
+/**
+ * Open the porthole device
+ *
+ * @param   handle       Returned handle if successful, otherwise undefined
+ * @param   socket_path  Path to the unix socket of the porthole char device
+ * @param   map_event    Callback for map events from the guest
+ * @param   unmap_event  Callback for unmap events from the guest
+ * @param   discon_event Callback for client socket disconnection
+ * @returns true on success
+ *
+ * If successful the handle must be closed to free resources when finished.
+ */
+bool porthole_client_open(
+  PortholeClient    * handle,
+  const char        * socket_path,
+  PortholeMapEvent    map_cb,
+  PortholeUnmapEvent  unmap_cb,
+  PortholeDisconEvent discon_cb);
+
+/**
+ * Close the porthole devce
+ *
+ * @param handle The porthole client handle obtained from porthole_client_open
+ *
+ * handle will be set to NULL and is no longer valid after calling this
+ * function and all mappings will become invalid.
+ */
+void porthole_client_close(PortholeClient * handle);
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