nat: add tracing for nat44-hairpinning

Type: improvement
Signed-off-by: Klement Sekera <ksekera@cisco.com>
Change-Id: Ife437f959e29d3de88bd7ee77221ada86fb03e80

3 files changed, 84 insertions, 15 deletions

diff --git a/src/plugins/nat/in2out.c b/src/plugins/nat/in2out.c
index 980a638f059..8616d90ad2b 100644
--- a/src/plugins/nat/in2out.c
+++ b/src/plugins/nat/in2out.c
@@ -43,6 +43,7 @@ typedef struct
   u32 next_index;
   u32 session_index;
   u32 is_slow_path;
+  u32 is_hairpinning;
 } snat_in2out_trace_t;
 
 /* packet trace format function */
@@ -58,6 +59,10 @@ format_snat_in2out_trace (u8 * s, va_list * args)
 
   s = format (s, "%s: sw_if_index %d, next index %d, session %d", tag,
 	      t->sw_if_index, t->next_index, t->session_index);
+  if (t->is_hairpinning)
+    {
+      s = format (s, ", with-hairpinning");
+    }
 
   return s;
 }
@@ -1776,6 +1781,7 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
   u32 pkts_processed = 0;
   snat_main_t *sm = &snat_main;
   u32 stats_node_index;
+  int is_hairpinning = 0;
 
   stats_node_index = sm->in2out_fast_node_index;
 
@@ -1923,7 +1929,9 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
 	    }
 
 	  /* Hairpinning */
-	  snat_hairpinning (sm, b0, ip0, udp0, tcp0, proto0, 0);
+	  snat_hairpinning (vm, node, sm, b0, ip0, udp0, tcp0, proto0, 0,
+			    0 /* do_trace */ );
+	  is_hairpinning = 1;
 
 	trace0:
 	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
@@ -1933,6 +1941,7 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
 		vlib_add_trace (vm, node, b0, sizeof (*t));
 	      t->sw_if_index = sw_if_index0;
 	      t->next_index = next0;
+	      t->is_hairpinning = is_hairpinning;
 	    }
 
 	  pkts_processed += next0 != SNAT_IN2OUT_NEXT_DROP;
diff --git a/src/plugins/nat/nat.h b/src/plugins/nat/nat.h
index de2353889da..fbf2105dea3 100644
--- a/src/plugins/nat/nat.h
+++ b/src/plugins/nat/nat.h
@@ -1069,9 +1069,11 @@ void nat_hairpinning_sm_unknown_proto (snat_main_t * sm, vlib_buffer_t * b,
 				       ip4_header_t * ip);
 void nat44_ed_hairpinning_unknown_proto (snat_main_t * sm, vlib_buffer_t * b,
 					 ip4_header_t * ip);
-int snat_hairpinning (snat_main_t * sm, vlib_buffer_t * b0,
+int snat_hairpinning (vlib_main_t * vm, vlib_node_runtime_t * node,
+		      snat_main_t * sm, vlib_buffer_t * b0,
 		      ip4_header_t * ip0, udp_header_t * udp0,
-		      tcp_header_t * tcp0, u32 proto0, int is_ed);
+		      tcp_header_t * tcp0, u32 proto0, int is_ed,
+		      int do_trace);
 
 /* Call back functions for clib_bihash_add_or_overwrite_stale */
 int nat44_i2o_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg);
diff --git a/src/plugins/nat/nat44_hairpinning.c b/src/plugins/nat/nat44_hairpinning.c
index 02cdfb12380..21e2eee188b 100644
--- a/src/plugins/nat/nat44_hairpinning.c
+++ b/src/plugins/nat/nat44_hairpinning.c
@@ -56,6 +56,36 @@ static char *nat44_hairpin_error_strings[] = {
 #undef _
 };
 
+typedef struct
+{
+  ip4_address_t addr;
+  u16 port;
+  u32 fib_index;
+  u32 session_index;
+} nat_hairpin_trace_t;
+
+static u8 *
+format_nat_hairpin_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  nat_hairpin_trace_t *t = va_arg (*args, nat_hairpin_trace_t *);
+
+  s =
+    format (s, "new dst addr %U port %u fib-index %u", format_ip4_address,
+	    &t->addr, clib_net_to_host_u16 (t->port), t->fib_index);
+  if (~0 == t->session_index)
+    {
+      s = format (s, " is-static-mapping");
+    }
+  else
+    {
+      s = format (s, " session-index %u", t->session_index);
+    }
+
+  return s;
+}
+
 extern vnet_feature_arc_registration_t vnet_feat_arc_ip4_local;
 
 static_always_inline int
@@ -86,18 +116,17 @@ is_hairpinning (snat_main_t * sm, ip4_address_t * dst_addr)
 
 #ifndef CLIB_MARCH_VARIANT
 int
-snat_hairpinning (snat_main_t * sm,
-		  vlib_buffer_t * b0,
-		  ip4_header_t * ip0,
-		  udp_header_t * udp0,
-		  tcp_header_t * tcp0, u32 proto0, int is_ed)
+snat_hairpinning (vlib_main_t * vm, vlib_node_runtime_t * node,
+		  snat_main_t * sm, vlib_buffer_t * b0, ip4_header_t * ip0,
+		  udp_header_t * udp0, tcp_header_t * tcp0, u32 proto0,
+		  int is_ed, int do_trace)
 {
   snat_session_key_t key0, sm0;
   snat_session_t *s0;
   clib_bihash_kv_8_8_t kv0, value0;
   ip_csum_t sum0;
-  u32 new_dst_addr0 = 0, old_dst_addr0, ti = 0, si;
-  u16 new_dst_port0, old_dst_port0;
+  u32 new_dst_addr0 = 0, old_dst_addr0, ti = 0, si = ~0;
+  u16 new_dst_port0 = ~0, old_dst_port0;
   int rv;
 
   key0.addr = ip0->dst_address;
@@ -140,7 +169,10 @@ snat_hairpinning (snat_main_t * sm,
 	  si = value0.value;
 	}
       if (rv)
-	return 0;
+	{
+	  rv = 0;
+	  goto trace;
+	}
 
       s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
       new_dst_addr0 = s0->in2out.addr.as_u32;
@@ -187,9 +219,28 @@ snat_hairpinning (snat_main_t * sm,
 	      tcp0->checksum = ip_csum_fold (sum0);
 	    }
 	}
-      return 1;
+      rv = 1;
+      goto trace;
     }
-  return 0;
+  rv = 0;
+trace:
+  if (do_trace && PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+				 && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+    {
+      nat_hairpin_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+      t->addr.as_u32 = new_dst_addr0;
+      t->port = new_dst_port0;
+      t->fib_index = vnet_buffer (b0)->sw_if_index[VLIB_TX];
+      if (s0)
+	{
+	  t->session_index = si;
+	}
+      else
+	{
+	  t->session_index = ~0;
+	}
+    }
+  return rv;
 }
 #endif
 
@@ -479,7 +530,9 @@ nat44_hairpinning_fn_inline (vlib_main_t * vm,
 	  vnet_get_config_data (&cm->config_main, &b0->current_config_index,
 				&next0, 0);
 
-	  if (snat_hairpinning (sm, b0, ip0, udp0, tcp0, proto0, is_ed))
+	  if (snat_hairpinning
+	      (vm, node, sm, b0, ip0, udp0, tcp0, proto0, is_ed,
+	       1 /* do_trace */ ))
 	    next0 = NAT_HAIRPIN_NEXT_LOOKUP;
 
 	  pkts_processed += next0 != NAT_HAIRPIN_NEXT_DROP;
@@ -511,6 +564,7 @@ VLIB_REGISTER_NODE (nat44_hairpinning_node) = {
   .vector_size = sizeof (u32),
   .type = VLIB_NODE_TYPE_INTERNAL,
   .n_errors = ARRAY_LEN(nat44_hairpin_error_strings),
+  .format_trace = format_nat_hairpin_trace,
   .error_strings = nat44_hairpin_error_strings,
   .n_next_nodes = NAT_HAIRPIN_N_NEXT,
   .next_nodes = {
@@ -534,6 +588,7 @@ VLIB_REGISTER_NODE (nat44_ed_hairpinning_node) = {
   .type = VLIB_NODE_TYPE_INTERNAL,
   .n_errors = ARRAY_LEN(nat44_hairpin_error_strings),
   .error_strings = nat44_hairpin_error_strings,
+  .format_trace = format_nat_hairpin_trace,
   .n_next_nodes = NAT_HAIRPIN_N_NEXT,
   .next_nodes = {
     [NAT_HAIRPIN_NEXT_DROP] = "error-drop",
@@ -595,7 +650,8 @@ snat_hairpin_dst_fn_inline (vlib_main_t * vm,
 		  udp_header_t *udp0 = ip4_next_header (ip0);
 		  tcp_header_t *tcp0 = (tcp_header_t *) udp0;
 
-		  snat_hairpinning (sm, b0, ip0, udp0, tcp0, proto0, is_ed);
+		  snat_hairpinning (vm, node, sm, b0, ip0, udp0, tcp0, proto0,
+				    is_ed, 1 /* do_trace */ );
 		}
 	      else if (proto0 == NAT_PROTOCOL_ICMP)
 		{
@@ -643,6 +699,7 @@ VLIB_REGISTER_NODE (snat_hairpin_dst_node) = {
   .vector_size = sizeof (u32),
   .type = VLIB_NODE_TYPE_INTERNAL,
   .n_errors = ARRAY_LEN(nat44_hairpin_error_strings),
+  .format_trace = format_nat_hairpin_trace,
   .error_strings = nat44_hairpin_error_strings,
   .n_next_nodes = NAT_HAIRPIN_N_NEXT,
   .next_nodes = {
@@ -665,6 +722,7 @@ VLIB_REGISTER_NODE (nat44_ed_hairpin_dst_node) = {
   .vector_size = sizeof (u32),
   .type = VLIB_NODE_TYPE_INTERNAL,
   .n_errors = ARRAY_LEN(nat44_hairpin_error_strings),
+  .format_trace = format_nat_hairpin_trace,
   .error_strings = nat44_hairpin_error_strings,
   .n_next_nodes = NAT_HAIRPIN_N_NEXT,
   .next_nodes = {