ip: Add ip46-local node for local swif[rx]

Type: improvement

This adds a new ip[46]-receive node, sibling
of ip[46]-local. Its goal is to set
vnet_buffer (b)->ip.rx_sw_if_index to the
sw_if_index of the local interface.

In dependant nodes further down the line (e.g.
hoststack) we then set sw_if_idx[rx] to this
value. So that we know which local interface
did receive the packet.

The TCP issue this fixes is that :

On accepts, we were setting tc->sw_if_index
to the source sw_if_index. We should use
the dest sw_if_index, so that packets
coming back on this connection have the
right source sw_if_index. And also setting
it in the tx-ed packet.

Change-Id: I569ed673e15c21e71f365c3ad45439b05bd14a9f
Signed-off-by: Nathan Skrzypczak <nathan.skrzypczak@gmail.com>

5 files changed, 132 insertions, 44 deletions

diff --git a/src/vnet/buffer.h b/src/vnet/buffer.h
index cbaf4d84e42..2b3152fbcd6 100644
--- a/src/vnet/buffer.h
+++ b/src/vnet/buffer.h
@@ -190,8 +190,17 @@ typedef struct
 	  /* Rewrite length */
 	  u8 save_rewrite_length;
 
-	  /* MFIB RPF ID */
-	  u32 rpf_id;
+	  union
+	  {
+	    /* sw_if_index of the local interface the buffer was received on
+	     * - if hitting a DPO_RECEIVE - it is set in ip[46]-receive.
+	     * This is ~0 if the dpo is not a receive dpo, or if the
+	     * interface is not specified (e.g. route add via local) */
+	    u32 rx_sw_if_index;
+
+	    /* MFIB RPF ID */
+	    u32 rpf_id;
+	  };
 	};
 
 	/* ICMP */
diff --git a/src/vnet/dpo/receive_dpo.c b/src/vnet/dpo/receive_dpo.c
index b12b382ce64..0a97e1d373b 100644
--- a/src/vnet/dpo/receive_dpo.c
+++ b/src/vnet/dpo/receive_dpo.c
@@ -156,15 +156,13 @@ const static dpo_vft_t receive_vft = {
  * this means that these graph nodes are ones from which a receive is the
  * parent object in the DPO-graph.
  */
-const static char* const receive_ip4_nodes[] =
-{
-    "ip4-local",
-    NULL,
+const static char *const receive_ip4_nodes[] = {
+  "ip4-receive",
+  NULL,
 };
-const static char* const receive_ip6_nodes[] =
-{
-    "ip6-local",
-    NULL,
+const static char *const receive_ip6_nodes[] = {
+  "ip6-receive",
+  NULL,
 };
 
 const static char* const * const receive_nodes[DPO_PROTO_NUM] =
diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
index 055df637c7f..900a1b4ce8e 100644
--- a/src/vnet/ip/ip4_forward.c
+++ b/src/vnet/ip/ip4_forward.c
@@ -52,6 +52,7 @@
 #include <vnet/mfib/ip4_mfib.h>
 #include <vnet/dpo/load_balance.h>
 #include <vnet/dpo/load_balance_map.h>
+#include <vnet/dpo/receive_dpo.h>
 #include <vnet/dpo/classify_dpo.h>
 #include <vnet/mfib/mfib_table.h>	/* for mFIB table and entry creation */
 #include <vnet/adj/adj_dp.h>
@@ -1387,10 +1388,9 @@ ip4_tcp_udp_validate_checksum (vlib_main_t * vm, vlib_buffer_t * p0)
 #endif
 
 /* *INDENT-OFF* */
-VNET_FEATURE_ARC_INIT (ip4_local) =
-{
-  .arc_name  = "ip4-local",
-  .start_nodes = VNET_FEATURES ("ip4-local"),
+VNET_FEATURE_ARC_INIT (ip4_local) = {
+  .arc_name = "ip4-local",
+  .start_nodes = VNET_FEATURES ("ip4-local", "ip4-receive"),
   .last_in_arc = "ip4-local-end-of-arc",
 };
 /* *INDENT-ON* */
@@ -1515,8 +1515,9 @@ typedef struct
 } ip4_local_last_check_t;
 
 static inline void
-ip4_local_check_src (vlib_buffer_t * b, ip4_header_t * ip0,
-		     ip4_local_last_check_t * last_check, u8 * error0)
+ip4_local_check_src (vlib_buffer_t *b, ip4_header_t *ip0,
+		     ip4_local_last_check_t *last_check, u8 *error0,
+		     int is_receive_dpo)
 {
   const dpo_id_t *dpo0;
   load_balance_t *lb0;
@@ -1526,6 +1527,15 @@ ip4_local_check_src (vlib_buffer_t * b, ip4_header_t * ip0,
     vnet_buffer (b)->sw_if_index[VLIB_TX] != ~0 ?
     vnet_buffer (b)->sw_if_index[VLIB_TX] : vnet_buffer (b)->ip.fib_index;
 
+  if (is_receive_dpo)
+    {
+      receive_dpo_t *rd;
+      rd = receive_dpo_get (vnet_buffer (b)->ip.adj_index[VLIB_TX]);
+      vnet_buffer (b)->ip.rx_sw_if_index = rd->rd_sw_if_index;
+    }
+  else
+    vnet_buffer (b)->ip.rx_sw_if_index = ~0;
+
   /*
    * vnet_buffer()->ip.adj_index[VLIB_RX] will be set to the index of the
    *  adjacency for the destination address (the local interface address).
@@ -1579,8 +1589,9 @@ ip4_local_check_src (vlib_buffer_t * b, ip4_header_t * ip0,
 }
 
 static inline void
-ip4_local_check_src_x2 (vlib_buffer_t ** b, ip4_header_t ** ip,
-			ip4_local_last_check_t * last_check, u8 * error)
+ip4_local_check_src_x2 (vlib_buffer_t **b, ip4_header_t **ip,
+			ip4_local_last_check_t *last_check, u8 *error,
+			int is_receive_dpo)
 {
   const dpo_id_t *dpo[2];
   load_balance_t *lb[2];
@@ -1601,6 +1612,20 @@ ip4_local_check_src_x2 (vlib_buffer_t ** b, ip4_header_t ** ip,
     vnet_buffer (b[1])->sw_if_index[VLIB_TX] :
     vnet_buffer (b[1])->ip.fib_index;
 
+  if (is_receive_dpo)
+    {
+      const receive_dpo_t *rd0, *rd1;
+      rd0 = receive_dpo_get (vnet_buffer (b[0])->ip.adj_index[VLIB_TX]);
+      rd1 = receive_dpo_get (vnet_buffer (b[1])->ip.adj_index[VLIB_TX]);
+      vnet_buffer (b[0])->ip.rx_sw_if_index = rd0->rd_sw_if_index;
+      vnet_buffer (b[1])->ip.rx_sw_if_index = rd1->rd_sw_if_index;
+    }
+  else
+    {
+      vnet_buffer (b[0])->ip.rx_sw_if_index = ~0;
+      vnet_buffer (b[1])->ip.rx_sw_if_index = ~0;
+    }
+
   /*
    * vnet_buffer()->ip.adj_index[VLIB_RX] will be set to the index of the
    *  adjacency for the destination address (the local interface address).
@@ -1697,9 +1722,9 @@ ip4_local_classify (vlib_buffer_t * b, ip4_header_t * ip, u16 * next)
 }
 
 static inline uword
-ip4_local_inline (vlib_main_t * vm,
-		  vlib_node_runtime_t * node,
-		  vlib_frame_t * frame, int head_of_feature_arc)
+ip4_local_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
+		  vlib_frame_t *frame, int head_of_feature_arc,
+		  int is_receive_dpo)
 {
   u32 *from, n_left_from;
   vlib_node_runtime_t *error_node =
@@ -1764,19 +1789,21 @@ ip4_local_inline (vlib_main_t * vm,
       if (PREDICT_TRUE (not_batch == 0))
 	{
 	  ip4_local_check_l4_csum_x2 (vm, b, ip, error);
-	  ip4_local_check_src_x2 (b, ip, &last_check, error);
+	  ip4_local_check_src_x2 (b, ip, &last_check, error, is_receive_dpo);
 	}
       else
 	{
 	  if (!pt[0])
 	    {
 	      ip4_local_check_l4_csum (vm, b[0], ip[0], &error[0]);
-	      ip4_local_check_src (b[0], ip[0], &last_check, &error[0]);
+	      ip4_local_check_src (b[0], ip[0], &last_check, &error[0],
+				   is_receive_dpo);
 	    }
 	  if (!pt[1])
 	    {
 	      ip4_local_check_l4_csum (vm, b[1], ip[1], &error[1]);
-	      ip4_local_check_src (b[1], ip[1], &last_check, &error[1]);
+	      ip4_local_check_src (b[1], ip[1], &last_check, &error[1],
+				   is_receive_dpo);
 	    }
 	}
 
@@ -1804,7 +1831,8 @@ ip4_local_inline (vlib_main_t * vm,
 	goto skip_check;
 
       ip4_local_check_l4_csum (vm, b[0], ip[0], &error[0]);
-      ip4_local_check_src (b[0], ip[0], &last_check, &error[0]);
+      ip4_local_check_src (b[0], ip[0], &last_check, &error[0],
+			   is_receive_dpo);
 
     skip_check:
 
@@ -1823,10 +1851,10 @@ ip4_local_inline (vlib_main_t * vm,
 VLIB_NODE_FN (ip4_local_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
 			       vlib_frame_t * frame)
 {
-  return ip4_local_inline (vm, node, frame, 1 /* head of feature arc */ );
+  return ip4_local_inline (vm, node, frame, 1 /* head of feature arc */,
+			   0 /* is_receive_dpo */);
 }
 
-/* *INDENT-OFF* */
 VLIB_REGISTER_NODE (ip4_local_node) =
 {
   .name = "ip4-local",
@@ -1844,17 +1872,29 @@ VLIB_REGISTER_NODE (ip4_local_node) =
     [IP_LOCAL_NEXT_REASSEMBLY] = "ip4-full-reassembly",
   },
 };
-/* *INDENT-ON* */
 
+VLIB_NODE_FN (ip4_receive_local_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+  return ip4_local_inline (vm, node, frame, 1 /* head of feature arc */,
+			   1 /* is_receive_dpo */);
+}
+
+VLIB_REGISTER_NODE (ip4_receive_local_node) = {
+  .name = "ip4-receive",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ip4_forward_next_trace,
+  .sibling_of = "ip4-local"
+};
 
 VLIB_NODE_FN (ip4_local_end_of_arc_node) (vlib_main_t * vm,
 					  vlib_node_runtime_t * node,
 					  vlib_frame_t * frame)
 {
-  return ip4_local_inline (vm, node, frame, 0 /* head of feature arc */ );
+  return ip4_local_inline (vm, node, frame, 0 /* head of feature arc */,
+			   0 /* is_receive_dpo */);
 }
 
-/* *INDENT-OFF* */
 VLIB_REGISTER_NODE (ip4_local_end_of_arc_node) = {
   .name = "ip4-local-end-of-arc",
   .vector_size = sizeof (u32),
@@ -1868,7 +1908,6 @@ VNET_FEATURE_INIT (ip4_local_end_of_arc, static) = {
   .node_name = "ip4-local-end-of-arc",
   .runs_before = 0, /* not before any other features */
 };
-/* *INDENT-ON* */
 
 #ifndef CLIB_MARCH_VARIANT
 void
diff --git a/src/vnet/ip/ip6_forward.c b/src/vnet/ip/ip6_forward.c
index d9c015f6fb4..b9f9892f929 100644
--- a/src/vnet/ip/ip6_forward.c
+++ b/src/vnet/ip/ip6_forward.c
@@ -48,6 +48,7 @@
 #include <vnet/fib/ip6_fib.h>
 #include <vnet/mfib/ip6_mfib.h>
 #include <vnet/dpo/load_balance_map.h>
+#include <vnet/dpo/receive_dpo.h>
 #include <vnet/dpo/classify_dpo.h>
 #include <vnet/classify/vnet_classify.h>
 #include <vnet/pg/pg.h>
@@ -1228,10 +1229,9 @@ ip6_next_proto_is_tcp_udp (vlib_buffer_t * p0, ip6_header_t * ip0,
 }
 
 /* *INDENT-OFF* */
-VNET_FEATURE_ARC_INIT (ip6_local) =
-{
-  .arc_name  = "ip6-local",
-  .start_nodes = VNET_FEATURES ("ip6-local"),
+VNET_FEATURE_ARC_INIT (ip6_local) = {
+  .arc_name = "ip6-local",
+  .start_nodes = VNET_FEATURES ("ip6-local", "ip6-receive"),
 };
 /* *INDENT-ON* */
 
@@ -1278,10 +1278,10 @@ ip6_tcp_udp_icmp_bad_length (vlib_main_t * vm, vlib_buffer_t * p0)
     return 1;
 }
 
-
 always_inline uword
-ip6_local_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
-		  vlib_frame_t * frame, int head_of_feature_arc)
+ip6_local_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
+		  vlib_frame_t *frame, int head_of_feature_arc,
+		  int is_receive_dpo)
 {
   ip6_main_t *im = &ip6_main;
   ip_lookup_main_t *lm = &im->lookup_main;
@@ -1469,6 +1469,21 @@ ip6_local_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 	    vnet_buffer (b[1])->sw_if_index[VLIB_TX] != ~0 ?
 	    vnet_buffer (b[1])->sw_if_index[VLIB_TX] :
 	    vnet_buffer (b[1])->ip.fib_index;
+	  if (is_receive_dpo)
+	    {
+	      const receive_dpo_t *rd0, *rd1;
+	      rd0 =
+		receive_dpo_get (vnet_buffer (b[0])->ip.adj_index[VLIB_TX]);
+	      rd1 =
+		receive_dpo_get (vnet_buffer (b[1])->ip.adj_index[VLIB_TX]);
+	      vnet_buffer (b[0])->ip.rx_sw_if_index = rd0->rd_sw_if_index;
+	      vnet_buffer (b[1])->ip.rx_sw_if_index = rd1->rd_sw_if_index;
+	    }
+	  else
+	    {
+	      vnet_buffer (b[0])->ip.rx_sw_if_index = ~0;
+	      vnet_buffer (b[1])->ip.rx_sw_if_index = ~0;
+	    }
 	}			/* head_of_feature_arc */
 
       next[0] = lm->local_next_by_ip_protocol[ip[0]->protocol];
@@ -1596,6 +1611,14 @@ ip6_local_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 	    vnet_buffer (b[0])->sw_if_index[VLIB_TX] != ~0 ?
 	    vnet_buffer (b[0])->sw_if_index[VLIB_TX] :
 	    vnet_buffer (b[0])->ip.fib_index;
+	  if (is_receive_dpo)
+	    {
+	      receive_dpo_t *rd;
+	      rd = receive_dpo_get (vnet_buffer (b[0])->ip.adj_index[VLIB_TX]);
+	      vnet_buffer (b[0])->ip.rx_sw_if_index = rd->rd_sw_if_index;
+	    }
+	  else
+	    vnet_buffer (b[0])->ip.rx_sw_if_index = ~0;
 	}			/* head_of_feature_arc */
 
       next[0] = lm->local_next_by_ip_protocol[ip->protocol];
@@ -1629,10 +1652,10 @@ ip6_local_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 VLIB_NODE_FN (ip6_local_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
 			       vlib_frame_t * frame)
 {
-  return ip6_local_inline (vm, node, frame, 1 /* head of feature arc */ );
+  return ip6_local_inline (vm, node, frame, 1 /* head of feature arc */,
+			   0 /* ip6_local_inline */);
 }
 
-/* *INDENT-OFF* */
 VLIB_REGISTER_NODE (ip6_local_node) =
 {
   .name = "ip6-local",
@@ -1648,16 +1671,29 @@ VLIB_REGISTER_NODE (ip6_local_node) =
     [IP_LOCAL_NEXT_REASSEMBLY] = "ip6-full-reassembly",
   },
 };
-/* *INDENT-ON* */
+
+VLIB_NODE_FN (ip6_receive_local_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+  return ip6_local_inline (vm, node, frame, 1 /* head of feature arc */,
+			   1 /* is_receive_dpo */);
+}
+
+VLIB_REGISTER_NODE (ip6_receive_local_node) = {
+  .name = "ip6-receive",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ip6_forward_next_trace,
+  .sibling_of = "ip6-local"
+};
 
 VLIB_NODE_FN (ip6_local_end_of_arc_node) (vlib_main_t * vm,
 					  vlib_node_runtime_t * node,
 					  vlib_frame_t * frame)
 {
-  return ip6_local_inline (vm, node, frame, 0 /* head of feature arc */ );
+  return ip6_local_inline (vm, node, frame, 0 /* head of feature arc */,
+			   0 /* ip6_local_inline */);
 }
 
-/* *INDENT-OFF* */
 VLIB_REGISTER_NODE (ip6_local_end_of_arc_node) = {
   .name = "ip6-local-end-of-arc",
   .vector_size = sizeof (u32),
@@ -1671,7 +1707,6 @@ VNET_FEATURE_INIT (ip6_local_end_of_arc, static) = {
   .node_name = "ip6-local-end-of-arc",
   .runs_before = 0, /* not before any other features */
 };
-/* *INDENT-ON* */
 
 #ifdef CLIB_MARCH_VARIANT
 extern vlib_node_registration_t ip6_local_node;
diff --git a/src/vnet/tcp/tcp_inlines.h b/src/vnet/tcp/tcp_inlines.h
index dfdf801d0ab..e82f308d9b8 100644
--- a/src/vnet/tcp/tcp_inlines.h
+++ b/src/vnet/tcp/tcp_inlines.h
@@ -237,6 +237,13 @@ tcp_input_lookup_buffer (vlib_buffer_t * b, u8 thread_index, u32 * error,
   tcp_header_t *tcp;
   u8 result = 0;
 
+  /* Set the sw_if_index[VLIB_RX] to the interface we received
+   * the connection on (the local interface) */
+  vnet_buffer (b)->sw_if_index[VLIB_RX] =
+    vnet_buffer (b)->ip.rx_sw_if_index != ~0 ?
+      vnet_buffer (b)->ip.rx_sw_if_index :
+      vnet_buffer (b)->sw_if_index[VLIB_RX];
+
   if (is_ip4)
     {
       ip4_header_t *ip4 = vlib_buffer_get_current (b);