buffers: configurable buffer fault injector

[vpp.git] / src / vlib / buffer.c

diff --git a/src/vlib/buffer.c b/src/vlib/buffer.c
index 43b1dd6..f5b8137 100644 (file)
--- a/src/vlib/buffer.c
+++ b/src/vlib/buffer.c
@@ -578,6 +578,14 @@ vlib_buffer_pool_create (vlib_main_t * vm, char *name, u32 data_size,
        p = m->base + (j << m->log2_page_size) + i * alloc_size;
        p += bm->ext_hdr_size;
 
+       /*
+        * Waste 1 buffer (maximum) so that 0 is never a valid buffer index.
+        * Allows various places to ASSERT (bi != 0). Much easier
+        * than debugging downstream crashes in successor nodes.
+        */
+       if (p == m->base)
+         continue;
+
        vlib_buffer_copy_template ((vlib_buffer_t *) p, &bp->buffer_template);
 
        bi = vlib_get_buffer_index (vm, (vlib_buffer_t *) p);
@@ -923,6 +931,24 @@ vlib_buffers_configure (vlib_main_t * vm, unformat_input_t * input)
 
 VLIB_EARLY_CONFIG_FUNCTION (vlib_buffers_configure, "buffers");
 
+#if VLIB_BUFFER_ALLOC_FAULT_INJECTOR > 0
+u32
+vlib_buffer_alloc_may_fail (vlib_main_t * vm, u32 n_buffers)
+{
+  f64 r;
+
+  r = random_f64 (&vm->buffer_alloc_success_seed);
+
+  /* Fail this request? */
+  if (r > vm->buffer_alloc_success_rate)
+    n_buffers--;
+  /* 5% chance of returning nothing at all */
+  if (r > vm->buffer_alloc_success_rate && r > 0.95)
+    n_buffers = 0;
+
+  return n_buffers;
+}
+#endif
 
 /** @endcond */
 /*