classify: vpp packet tracer support

Configure n-tuple classifier filters which apply to the vpp packet
tracer.

Update the documentation to reflect the new feature.

Add a test vector.

Type: feature

Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: Iefa911716c670fc12e4825b937b62044433fec36
(cherry picked from commit 87d24db65facb89ca524c951b8379ca2ec4dbc7a)

3 files changed, 58 insertions, 1 deletions

diff --git a/src/vlib/main.h b/src/vlib/main.h
index e230ddf8419..af6539efc75 100644
--- a/src/vlib/main.h
+++ b/src/vlib/main.h
@@ -73,6 +73,13 @@ typedef struct
   u32 filter_classify_table_index;
 } vnet_pcap_t;
 
+typedef struct
+{
+  u8 trace_filter_enable;
+  u32 trace_classify_table_index;
+  u32 trace_filter_set_index;
+} vlib_trace_filter_t;
+
 typedef struct vlib_main_t
 {
   CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
@@ -165,6 +172,9 @@ typedef struct vlib_main_t
   /* pcap rx / tx tracing */
   vnet_pcap_t pcap;
 
+  /* Packet trace capture filter */
+  vlib_trace_filter_t trace_filter;
+
   /* Error handling. */
   vlib_error_main_t error_main;
 
diff --git a/src/vlib/trace.c b/src/vlib/trace.c
index 530598d349d..7ee1b63f07e 100644
--- a/src/vlib/trace.c
+++ b/src/vlib/trace.c
@@ -351,6 +351,13 @@ VLIB_CLI_COMMAND (show_trace_cli,static) = {
 };
 /* *INDENT-ON* */
 
+int vlib_enable_disable_pkt_trace_filter (int enable) __attribute__ ((weak));
+int
+vlib_enable_disable_pkt_trace_filter (int enable)
+{
+  return 0;
+}
+
 static clib_error_t *
 cli_add_trace_buffer (vlib_main_t * vm,
 		      unformat_input_t * input, vlib_cli_command_t * cmd)
@@ -361,6 +368,7 @@ cli_add_trace_buffer (vlib_main_t * vm,
   vlib_trace_node_t *tn;
   u32 node_index, add;
   u8 verbose = 0;
+  int filter = 0;
   clib_error_t *error = 0;
 
   if (!unformat_user (input, unformat_line_input, line_input))
@@ -376,6 +384,8 @@ cli_add_trace_buffer (vlib_main_t * vm,
 	;
       else if (unformat (line_input, "verbose"))
 	verbose = 1;
+      else if (unformat (line_input, "filter"))
+	filter = 1;
       else
 	{
 	  error = clib_error_create ("expected NODE COUNT, got `%U'",
@@ -395,6 +405,15 @@ cli_add_trace_buffer (vlib_main_t * vm,
       goto done;
     }
 
+  if (filter)
+    {
+      if (vlib_enable_disable_pkt_trace_filter (1 /* enable */ ))
+	{
+	  error = clib_error_create ("No packet trace filter configured...");
+	  goto done;
+	}
+    }
+
   /* *INDENT-OFF* */
   foreach_vlib_main ((
     {
@@ -421,7 +440,6 @@ VLIB_CLI_COMMAND (add_trace_cli,static) = {
 };
 /* *INDENT-ON* */
 
-
 /*
  * Configure a filter for packet traces.
  *
@@ -523,6 +541,7 @@ static clib_error_t *
 cli_clear_trace_buffer (vlib_main_t * vm,
 			unformat_input_t * input, vlib_cli_command_t * cmd)
 {
+  vlib_enable_disable_pkt_trace_filter (0 /* enable */ );
   clear_trace_buffer ();
   return 0;
 }
@@ -541,6 +560,18 @@ vlib_trace_cli_reference (void)
 {
 }
 
+int
+vnet_is_packet_traced (vlib_buffer_t * b,
+		       u32 classify_table_index, int func)
+__attribute__ ((weak));
+
+int
+vnet_is_packet_traced (vlib_buffer_t * b, u32 classify_table_index, int func)
+{
+  clib_warning ("BUG: STUB called");
+  return 1;
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/vlib/trace_funcs.h b/src/vlib/trace_funcs.h
index 257c3a3a4ff..4261f675aec 100644
--- a/src/vlib/trace_funcs.h
+++ b/src/vlib/trace_funcs.h
@@ -61,6 +61,9 @@ vlib_add_trace (vlib_main_t * vm,
 
   ASSERT (vnet_trace_dummy);
 
+  if (PREDICT_FALSE ((b->flags & VLIB_BUFFER_IS_TRACED) == 0))
+    return vnet_trace_dummy;
+
   if (PREDICT_FALSE (tm->add_trace_callback != 0))
     {
       return tm->add_trace_callback ((struct vlib_main_t *) vm,
@@ -118,6 +121,9 @@ vlib_trace_next_frame (vlib_main_t * vm,
 }
 
 void trace_apply_filter (vlib_main_t * vm);
+int vnet_is_packet_traced (vlib_buffer_t * b,
+			   u32 classify_table_index, int func);
+
 
 /* Mark buffer as traced and allocate trace buffer. */
 always_inline void
@@ -131,6 +137,16 @@ vlib_trace_buffer (vlib_main_t * vm,
   if (PREDICT_FALSE (tm->trace_enable == 0))
     return;
 
+  /* Classifier filter in use? */
+  if (PREDICT_FALSE (vlib_global_main.trace_filter.trace_filter_enable))
+    {
+      /* See if we're supposed to trace this packet... */
+      if (vnet_is_packet_traced
+	  (b, vlib_global_main.trace_filter.trace_classify_table_index,
+	   0 /* full classify */ ) != 1)
+	return;
+    }
+
   /*
    * Apply filter to existing traces to keep number of allocated traces low.
    * Performed each time around the main loop.