tcp: add option for always on event logging

Type: feature

Add option to always compile in debugging infra. Debug verbosity can be
controlled via configuration updatable via cli. Compile time inclusion
and configuration of event logging verbosity is still available in order
to minimize event logging impact.

Change-Id: I9d946efe9fa4204fdace1adb1d6588c97b5ae758
Signed-off-by: Florin Coras <fcoras@cisco.com>
(cherry picked from commit a436a42221280888acd09858c7353e694c359bca)

1 files changed, 127 insertions, 0 deletions

diff --git a/src/vnet/tcp/tcp_debug.c b/src/vnet/tcp/tcp_debug.c
new file mode 100644
index 00000000000..cf61d226c7f
--- /dev/null
+++ b/src/vnet/tcp/tcp_debug.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <vnet/tcp/tcp_debug.h>
+
+tcp_dbg_main_t tcp_dbg_main;
+
+void
+tcp_evt_track_register (elog_track_t * et)
+{
+  tcp_dbg_main_t *tdm = &tcp_dbg_main;
+  u32 fl_len, track_index;
+
+  fl_len = vec_len (tdm->free_track_indices);
+  if (fl_len)
+    {
+      track_index = tdm->free_track_indices[fl_len - 1];
+      _vec_len (tdm->free_track_indices) -= 1;
+      et->track_index_plus_one = track_index + 1;
+    }
+  else
+    elog_track_register (&vlib_global_main.elog_main, et);
+}
+
+static const char *tcp_evt_grp_str[] = {
+#define _(sym, str) str,
+  foreach_tcp_evt_grp
+#undef _
+};
+
+static void
+tcp_debug_show_groups (void)
+{
+  tcp_dbg_main_t *tdm = &tcp_dbg_main;
+  vlib_main_t *vm = vlib_get_main ();
+  int i = 0;
+
+  vlib_cli_output (vm, "%-10s%-30s%-10s", "Index", "Group", "Level");
+
+  for (i = 0; i < TCP_EVT_N_GRP; i++)
+    vlib_cli_output (vm, "%-10d%-30s%-10d", i, tcp_evt_grp_str[i],
+		     tdm->grp_dbg_lvl[i]);
+}
+
+static clib_error_t *
+tcp_debug_fn (vlib_main_t * vm, unformat_input_t * input,
+	      vlib_cli_command_t * cmd)
+{
+  unformat_input_t _line_input, *line_input = &_line_input;
+  tcp_dbg_main_t *tdm = &tcp_dbg_main;
+  u32 group = ~0, level = ~0;
+  clib_error_t *error = 0;
+  u8 is_show = 0;
+
+  if (!TCP_DEBUG_ALWAYS)
+    return clib_error_return (0, "must compile with TCP_DEBUG_ALWAYS set");
+
+  if (!unformat_user (input, unformat_line_input, line_input))
+    return clib_error_return (0, "expected enable | disable");
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "show"))
+	is_show = 1;
+      else if (unformat (line_input, "group %d", &group))
+	;
+      else if (unformat (line_input, "level %d", &level))
+	;
+      else
+	{
+	  error = clib_error_return (0, "unknown input `%U'",
+				     format_unformat_error, line_input);
+	  goto done;
+	}
+    }
+
+  if (is_show)
+    {
+      tcp_debug_show_groups ();
+      goto done;
+    }
+  if (group >= TCP_EVT_N_GRP)
+    {
+      error = clib_error_return (0, "group out of bounds");
+      goto done;
+    }
+  if (group == ~0 || level == ~0)
+    {
+      error = clib_error_return (0, "group and level must be set");
+      goto done;
+    }
+
+  tdm->grp_dbg_lvl[group] = level;
+
+done:
+
+  unformat_free (line_input);
+  return error;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (tcp_debug_command, static) =
+{
+  .path = "tcp debug",
+  .short_help = "tcp [show] [debug group <N> level <N>]",
+  .function = tcp_debug_fn,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */