+/**
+ * Discards bytes from buffer chain
+ *
+ * It discards n_bytes_to_drop starting at first buffer after chain_b
+ */
+always_inline void
+session_enqueue_discard_chain_bytes (vlib_main_t * vm, vlib_buffer_t * b,
+ vlib_buffer_t ** chain_b,
+ u32 n_bytes_to_drop)
+{
+ vlib_buffer_t *next = *chain_b;
+ u32 to_drop = n_bytes_to_drop;
+ ASSERT (b->flags & VLIB_BUFFER_NEXT_PRESENT);
+ while (to_drop && (next->flags & VLIB_BUFFER_NEXT_PRESENT))
+ {
+ next = vlib_get_buffer (vm, next->next_buffer);
+ if (next->current_length > to_drop)
+ {
+ vlib_buffer_advance (next, to_drop);
+ to_drop = 0;
+ }
+ else
+ {
+ to_drop -= next->current_length;
+ next->current_length = 0;
+ }
+ }
+ *chain_b = next;
+
+ if (to_drop == 0)
+ b->total_length_not_including_first_buffer -= n_bytes_to_drop;
+}
+
+/**
+ * Enqueue buffer chain tail
+ */