vnet: introduce vnet_error()

Decouples vnet return values from API return codes.

New vnet_error() creates vnet_error_t whicgh contains both vnet function
return value and return string.

vnet_api_error() converts vlib_error_t constructed with vnet_error() to
API return value.

Type: improvement
Change-Id: I17042954d48c010150fc1dfc5fce9330e8149e87
Signed-off-by: Damjan Marion <damarion@cisco.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/src/vnet/error.c b/src/vnet/error.c
new file mode 100644
index 00000000000..473d11135f1
--- /dev/null
+++ b/src/vnet/error.c
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2022 Cisco Systems, Inc.
+ */
+
+#include <vppinfra/error.h>
+#include <vnet/api_errno.h>
+
+static char *error_strings[] = {
+#define _(a, b, c) [-(b)] = c,
+  foreach_vnet_error
+#undef _
+};
+
+clib_error_t *
+vnet_error (vnet_error_t rv, char *fmt, ...)
+{
+  clib_error_t *e, *err = 0;
+  va_list va;
+  vec_add2 (err, e, 1);
+  e->what = format (e->what, "%s", error_strings[-rv]);
+
+  if (fmt)
+    {
+      vec_add1 (e->what, ' ');
+      vec_add1 (e->what, '(');
+      va_start (va, fmt);
+      e->what = va_format (e->what, fmt, &va);
+      vec_add1 (e->what, ')');
+      va_end (va);
+    }
+
+  e->code = rv;
+  return err;
+}
+
+u8 *
+format_vnet_api_errno (u8 *s, va_list *args)
+{
+  vnet_api_error_t api_error = va_arg (*args, vnet_api_error_t);
+#ifdef _
+#undef _
+#endif
+#define _(a, b, c)                                                            \
+  case b:                                                                     \
+    s = format (s, "%s", c);                                                  \
+    break;
+  switch (api_error)
+    {
+      foreach_vnet_error default : s = format (s, "UNKNOWN");
+      break;
+    }
+  return s;
+#undef _
+}