memif: add private header size field

private header size allows to reserve firs X bytes of payload to be
considered as private metadata. For now we just support value 0
but adding this field to address future needs without changing protocol
version.

Change-Id: Id77336584c0194a303b20210aff584c7372cba01
Signed-off-by: Damjan Marion <damarion@cisco.com>

diff --git a/src/plugins/memif/memif.h b/src/plugins/memif/memif.h
index 38b5402..3fbce91 100644 (file)
--- a/src/plugins/memif/memif.h
+++ b/src/plugins/memif/memif.h
@@ -103,6 +103,7 @@ typedef struct __attribute__ ((packed))
   memif_region_index_t region;
   memif_region_offset_t offset;
   memif_log2_ring_size_t log2_ring_size;
+  uint16_t private_hdr_size;   /* used for private metadata */
 } memif_msg_add_ring_t;
 
 typedef struct __attribute__ ((packed))

diff --git a/src/plugins/memif/socket.c b/src/plugins/memif/socket.c
index 384a7b1..34bff16 100644 (file)
--- a/src/plugins/memif/socket.c
+++ b/src/plugins/memif/socket.c
@@ -153,6 +153,7 @@ memif_msg_enq_add_ring (memif_if_t * mif, u8 index, u8 direction)
   ar->offset = mq->offset;
   ar->log2_ring_size = mq->log2_ring_size;
   ar->flags = (direction == MEMIF_RING_S2M) ? MEMIF_MSG_ADD_RING_FLAG_S2M : 0;
+  ar->private_hdr_size = 0;
 }
 
 static void
@@ -326,6 +327,9 @@ memif_msg_receive_add_ring (memif_if_t * mif, memif_msg_t * msg, int fd)
   if (fd < 0)
     return clib_error_return (0, "missing ring interrupt fd");
 
+  if (ar->private_hdr_size != 0)
+    return clib_error_return (0, "private headers not supported");
+
   if (ar->flags & MEMIF_MSG_ADD_RING_FLAG_S2M)
     {
       if (ar->index != vec_len (mif->rx_queues))