classify: per-interface rx/tx pcap capture filters

Finish the feature, and fix a couple of doc bugs

Type: feature

Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: I2c62745fda137776204c8fc4fca0e7e288051573

docs/gettingstarted/developers/vnet.md

@@ -549,22 +549,30 @@ not, the CLI command add a new table and the indicated mask rule
 ### Configure a simple pcap classify filter
 
 ```
-    classify filter pcap mask l3 ip4 src match l3 ip4 src 192.168.1.11"
-    pcap rx trace on max 100 filter
+    classify filter pcap mask l3 ip4 src match l3 ip4 src 192.168.1.11
+    pcap trace rx max 100 filter
 ```
 
-### Configure a simple interface packet-tracer filter
+### Configure a simple per-interface capture filter
 
 ```
     classify filter GigabitEthernet3/0/0 mask l3 ip4 src match l3 ip4 src 192.168.1.11"
-    [device-driver debug CLI TBD]
+    pcap trace rx max 100 intfc GigabitEthernet3/0/0
+```
+
+Note that per-interface capture filters are _always_ applied.
+
+### Clear per-interface capture filters
+
+```
+    classify filter GigabitEthernet3/0/0 del
 ```
 
 ### Configure another fairly simple pcap classify filter
 
 ```
    classify filter pcap mask l3 ip4 src dst match l3 ip4 src 192.168.1.10 dst 192.168.2.10
-   pcap tx trace on max 100 filter
+   pcap trace tx max 100 filter
 ```
 
 ### Clear all current classifier filters

src/vnet/ethernet/node.c

@@ -1125,8 +1125,18 @@ ethernet_input_trace (vlib_main_t * vm, vlib_node_runtime_t * node,
 	  if (pp->pcap_sw_if_index == 0 ||
 	      pp->pcap_sw_if_index == vnet_buffer (b0)->sw_if_index[VLIB_RX])
 	    {
-	      pcap_add_buffer (&pp->pcap_main, vm, bi0,
-			       pp->max_bytes_per_pkt);
+	      vnet_main_t *vnm = vnet_get_main ();
+	      vnet_hw_interface_t *hi =
+		vnet_get_sup_hw_interface
+		(vnm, vnet_buffer (b0)->sw_if_index[VLIB_RX]);
+
+	      /* Capture pkt if not filtered, or if filter hits */
+	      if (hi->trace_classify_table_index == ~0 ||
+		  vnet_is_packet_traced_inline
+		  (b0, hi->trace_classify_table_index,
+		   0 /* full classify */ ))
+		pcap_add_buffer (&pp->pcap_main, vm, bi0,
+				 pp->max_bytes_per_pkt);
 	    }
 	}
     }

src/vnet/interface_output.c

@@ -503,7 +503,16 @@ static_always_inline void vnet_interface_pcap_tx_trace
 	sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_TX];
 
       if (pp->pcap_sw_if_index == 0 || pp->pcap_sw_if_index == sw_if_index)
-	pcap_add_buffer (&pp->pcap_main, vm, bi0, pp->max_bytes_per_pkt);
+	{
+	  vnet_main_t *vnm = vnet_get_main ();
+	  vnet_hw_interface_t *hi =
+	    vnet_get_sup_hw_interface (vnm, sw_if_index);
+	  /* Capture pkt if not filtered, or if filter hits */
+	  if (hi->trace_classify_table_index == ~0 ||
+	      vnet_is_packet_traced_inline
+	      (b0, hi->trace_classify_table_index, 0 /* full classify */ ))
+	    pcap_add_buffer (&pp->pcap_main, vm, bi0, pp->max_bytes_per_pkt);
+	}
     }
 }