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-rw-r--r--src/vlib/buffer.h68
1 files changed, 68 insertions, 0 deletions
diff --git a/src/vlib/buffer.h b/src/vlib/buffer.h
index 1f723f3b677..69c8c7ccb09 100644
--- a/src/vlib/buffer.h
+++ b/src/vlib/buffer.h
@@ -240,6 +240,74 @@ vlib_get_buffer_opaque2 (vlib_buffer_t * b)
return (void *) b->opaque2;
}
+/** \brief Get pointer to the end of buffer's data
+ * @param b pointer to the buffer
+ * @return pointer to tail of packet's data
+ */
+always_inline u8 *
+vlib_buffer_get_tail (vlib_buffer_t * b)
+{
+ return b->data + b->current_data + b->current_length;
+}
+
+/** \brief Append uninitialized data to buffer
+ * @param b pointer to the buffer
+ * @param size number of uninitialized bytes
+ * @return pointer to beginning of uninitialized data
+ */
+always_inline void *
+vlib_buffer_put_uninit (vlib_buffer_t * b, u8 size)
+{
+ void *p = vlib_buffer_get_tail (b);
+ /* XXX make sure there's enough space */
+ b->current_length += size;
+ return p;
+}
+
+/** \brief Prepend uninitialized data to buffer
+ * @param b pointer to the buffer
+ * @param size number of uninitialized bytes
+ * @return pointer to beginning of uninitialized data
+ */
+always_inline void *
+vlib_buffer_push_uninit (vlib_buffer_t * b, u8 size)
+{
+ ASSERT (b->current_data + VLIB_BUFFER_PRE_DATA_SIZE >= size);
+ b->current_data -= size;
+ b->current_length += size;
+
+ return vlib_buffer_get_current (b);
+}
+
+/** \brief Make head room, typically for packet headers
+ * @param b pointer to the buffer
+ * @param size number of head room bytes
+ * @return pointer to start of buffer (current data)
+ */
+always_inline void *
+vlib_buffer_make_headroom (vlib_buffer_t * b, u8 size)
+{
+ ASSERT (b->current_data + VLIB_BUFFER_PRE_DATA_SIZE >= size);
+ b->current_data += size;
+ return vlib_buffer_get_current (b);
+}
+
+/** \brief Retrieve bytes from buffer head
+ * @param b pointer to the buffer
+ * @param size number of bytes to pull
+ * @return pointer to start of buffer (current data)
+ */
+always_inline void *
+vlib_buffer_pull (vlib_buffer_t * b, u8 size)
+{
+ if (b->current_length + VLIB_BUFFER_PRE_DATA_SIZE < size)
+ return 0;
+
+ void *data = vlib_buffer_get_current (b);
+ vlib_buffer_advance (b, size);
+ return data;
+}
+
/* Forward declaration. */
struct vlib_main_t;