feat(hicn-plugin): reuse strategy node to forward interests

Before the interest forwarding was duplicated in 2 different nodes,
the strategy_node and the interest_hitpit_node.
Reuse the strategy node so that the nexthop selection via the strategy
is done only in one place - teh strategy node.

Change-Id: I2c72ec35b1df4e6ed8ce0877e9f3e6f5c1ae68f8
Signed-off-by: Mauro Sardara <msardara@cisco.com>
(cherry picked from commit 4ec2784197db60e4f287a88b7944ecb1067bfc08)

3 files changed, 91 insertions, 175 deletions

diff --git a/hicn-plugin/src/interest_hitpit_node.c b/hicn-plugin/src/interest_hitpit_node.c
index 0b09711f7..fb2393f54 100644
--- a/hicn-plugin/src/interest_hitpit_node.c
+++ b/hicn-plugin/src/interest_hitpit_node.c
@@ -38,8 +38,6 @@ static char *hicn_interest_hitpit_error_strings[] = {
 
 vlib_node_registration_t hicn_interest_hitpit_node;
 
-always_inline void drop_packet (u32 *next0);
-
 /*
  * hICN forwarder node for interests hitting the PIT
  */
@@ -47,7 +45,6 @@ static uword
 hicn_interest_hitpit_node_fn (vlib_main_t *vm, vlib_node_runtime_t *node,
 			      vlib_frame_t *frame)
 {
-  int ret;
   u32 n_left_from, *from, *to_next;
   hicn_interest_hitpit_next_t next_index;
   hicn_interest_hitpit_runtime_t *rt;
@@ -62,9 +59,6 @@ hicn_interest_hitpit_node_fn (vlib_main_t *vm, vlib_node_runtime_t *node,
   const hicn_dpo_vft_t *dpo_vft0;
   u8 dpo_ctx_id0;
   u8 forward = 0;
-  hicn_face_id_t outfaces[MAX_OUT_FACES];
-  u32 clones[MAX_OUT_FACES];
-  u16 outfaces_len;
   u32 pit_entry_index;
   hicn_pcs_entry_t *pcs_entry = NULL;
   hicn_buffer_t *hicnb0;
@@ -119,152 +113,56 @@ hicn_interest_hitpit_node_fn (vlib_main_t *vm, vlib_node_runtime_t *node,
 	  // Increment packet counter
 	  stats.pkts_processed += 1;
 
-	  // If the entry is expired, remove it no matter of the possible
-	  // cases.
-	  if (tnow > hicn_pcs_entry_get_expire_time (pcs_entry))
+	  // A data packet may have arrived in the time between the pcs
+	  // lookup and now. Check again to make sure the entry is CS or
+	  // PIT
+	  if (hicn_pcs_entry_is_cs (pcs_entry))
 	    {
-	      // Notify strategy
-	      strategy_vft0->hicn_on_interest_timeout (dpo_ctx_id0);
-
-	      // Release lock on entry - this MUST delete the entry
-	      hicn_pcs_entry_remove_lock (rt->pitcs, pcs_entry);
-
-	      stats.pit_expired_count++;
-
-	      // Forward to strategy node
-	      // TODO this can be simplified by checking directly in the
-	      // pcslookup node!
-	      next0 = HICN_INTEREST_HITPIT_NEXT_STRATEGY;
+	      next0 = HICN_INTEREST_HITPIT_NEXT_INTEREST_HITCS;
 	    }
 	  else
 	    {
-	      // A data packet may have arrived in the time between the pcs
-	      // lookup and now. Check again to make sure the entry is CS or
-	      // PIT
-	      if (hicn_pcs_entry_is_cs (pcs_entry))
+	      // Distinguish between aggregation, retransmission and
+	      // additionally check if the strategy mandates to always send
+	      // the interest
+
+	      // Retransmission
+	      forward = hicn_pcs_entry_pit_search (pcs_entry, hicnb0->face_id);
+
+	      // Strategy mandates to force send after aggregation
+	      if (!forward && strategy_vft0->hicn_send_after_aggregation (
+				dpo_ctx_id0, hicnb0->face_id))
+		{
+		  forward = true;
+		  hicn_pcs_entry_pit_add_face (pcs_entry, hicnb0->face_id);
+		}
+
+	      if (forward && hicnb0->payload_type != HPT_MANIFEST)
 		{
-		  next0 = HICN_INTEREST_HITPIT_NEXT_INTEREST_HITCS;
+		  next0 = HICN_INTEREST_HITPIT_NEXT_STRATEGY;
 		}
 	      else
 		{
-		  // Distinguish between aggregation, retransmission and
-		  // additionally check if the strategy mandates to always send
-		  // the interest
-
-		  // Retransmission
-		  forward =
-		    hicn_pcs_entry_pit_search (pcs_entry, hicnb0->face_id);
-
-		  // Strategy mandates to force send after aggregation
-		  if (!forward && strategy_vft0->hicn_send_after_aggregation (
-				    dpo_ctx_id0, hicnb0->face_id))
-		    {
-		      forward = true;
-		      hicn_pcs_entry_pit_add_face (pcs_entry, hicnb0->face_id);
-		    }
-
-		  if (forward && hicnb0->payload_type != HPT_MANIFEST)
-		    {
-		      // Send interest
-		      strategy_vft0->hicn_select_next_hop (
-			dpo_ctx_id0, hicnb0->face_id, outfaces, &outfaces_len);
-
-		      // If no next hops, drop the packet
-		      if (outfaces_len == 0)
-			{
-			  drop_packet (&next0);
-			  vlib_validate_buffer_enqueue_x1 (
-			    vm, node, next_index, to_next, n_left_to_next, bi0,
-			    next0);
-			  continue;
-			}
-
-		      // Prepare the packet for the forwarding
-		      next0 = isv6 ? HICN_INTEREST_HITPIT_NEXT_FACE6_OUTPUT :
-					   HICN_INTEREST_HITPIT_NEXT_FACE4_OUTPUT;
+		  // Aggregation
+		  hicn_pcs_entry_pit_add_face (pcs_entry, hicnb0->face_id);
 
-		      // Update stats
-		      stats.interests_retx += outfaces_len;
+		  next0 = HICN_INTEREST_HITPIT_NEXT_ERROR_DROP;
 
-		      // Clone interest if needed
-		      if (outfaces_len > 1)
-			{
-			  ret = vlib_buffer_clone (vm, bi0, clones,
-						   (u16) outfaces_len,
-						   CLIB_CACHE_LINE_BYTES * 2);
-			  ASSERT (ret == outfaces_len);
-			}
-		      else
-			{
-			  clones[0] = bi0;
-			}
-
-		      // We need to clone the packet over multiple output
-		      // faces
-
-		      // Restore pointers
-		      to_next -= 1;
-		      n_left_to_next += 1;
-
-		      for (u32 nh = 0; nh < outfaces_len; nh++)
-			{
-			  vlib_buffer_t *local_b0 =
-			    vlib_get_buffer (vm, clones[nh]);
-			  to_next[0] = clones[nh];
-			  to_next += 1;
-			  n_left_to_next -= 1;
-
-			  vnet_buffer (local_b0)->ip.adj_index[VLIB_TX] =
-			    outfaces[nh];
-
-			  /* Maybe trace */
-			  if (PREDICT_FALSE (
-				(node->flags & VLIB_NODE_FLAG_TRACE) &&
-				(local_b0->flags & VLIB_BUFFER_IS_TRACED)))
-			    {
-			      hicn_interest_hitpit_trace_t *t =
-				vlib_add_trace (vm, node, local_b0,
-						sizeof (*t));
-			      t->pkt_type = HICN_PACKET_TYPE_INTEREST;
-			      t->sw_if_index =
-				vnet_buffer (local_b0)->sw_if_index[VLIB_RX];
-			      t->next_index = next0;
-			    }
-
-			  /*
-			   * Verify speculative enqueue, maybe switch
-			   * current next frame
-			   */
-			  vlib_validate_buffer_enqueue_x1 (
-			    vm, node, next_index, to_next, n_left_to_next,
-			    clones[nh], next0);
-			}
-		      continue;
-		    }
-		  else
-		    {
-		      // Aggregation
-		      hicn_pcs_entry_pit_add_face (pcs_entry, hicnb0->face_id);
-
-		      drop_packet (&next0);
-		      stats.interests_aggregated++;
-
-		      /* Maybe trace */
-		      if (PREDICT_FALSE (
-			    (node->flags & VLIB_NODE_FLAG_TRACE) &&
-			    (b0->flags & VLIB_BUFFER_IS_TRACED)))
-			{
-			  hicn_interest_hitpit_trace_t *t =
-			    vlib_add_trace (vm, node, b0, sizeof (*t));
-			  t->pkt_type = HICN_PACKET_TYPE_INTEREST;
-			  t->sw_if_index =
-			    vnet_buffer (b0)->sw_if_index[VLIB_RX];
-			  t->next_index = next0;
-			}
-		    }
+		  stats.interests_aggregated++;
 		}
 	    }
 
+	  /* Maybe trace */
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
+			     (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      hicn_interest_hitpit_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->pkt_type = HICN_PACKET_TYPE_INTEREST;
+	      t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+	      t->next_index = next0;
+	    }
+
 	  /*
 	   * Verify speculative enqueue, maybe switch current
 	   * next frame
@@ -311,12 +209,6 @@ hicn_interest_hitpit_format_trace (u8 *s, va_list *args)
   return (s);
 }
 
-void
-drop_packet (u32 *next0)
-{
-  *next0 = HICN_INTEREST_HITPIT_NEXT_ERROR_DROP;
-}
-
 /*
  * Node registration for the interest forwarder node
  */
diff --git a/hicn-plugin/src/interest_pcslookup_node.c b/hicn-plugin/src/interest_pcslookup_node.c
index a0b2ee3f0..e8aad4a83 100644
--- a/hicn-plugin/src/interest_pcslookup_node.c
+++ b/hicn-plugin/src/interest_pcslookup_node.c
@@ -80,6 +80,7 @@ hicn_interest_pcslookup_node_inline (vlib_main_t *vm,
   hicn_pcs_entry_t *pcs_entry = NULL;
   f64 tnow;
   hicn_buffer_t *hicnb0;
+  const hicn_strategy_vft_t *strategy;
 
   rt = vlib_node_get_runtime_data (vm, hicn_interest_pcslookup_node.index);
 
@@ -132,49 +133,72 @@ hicn_interest_pcslookup_node_inline (vlib_main_t *vm,
 
 	  if (ret == HICN_ERROR_NONE)
 	    {
-	      // We found an entry in the PCS. Next stage for this packet is
-	      // one of hitpit/cs nodes
-	      next0 = HICN_INTEREST_PCSLOOKUP_NEXT_INTEREST_HITPIT +
-		      hicn_pcs_entry_is_cs (pcs_entry);
-
+	      // We found an entry in the PCS.
 	      ret = hicn_store_internal_state (
 		b0, hicn_pcs_entry_get_index (rt->pitcs, pcs_entry),
 		vnet_buffer (b0)->ip.adj_index[VLIB_TX]);
 
-	      if (PREDICT_FALSE (ret != HICN_ERROR_NONE))
-		next0 = HICN_INTEREST_PCSLOOKUP_NEXT_ERROR_DROP;
-	    }
-	  else
-	    {
-	      // No entry in PCS. Let's create one now
-	      pcs_entry = hicn_pcs_entry_pit_get (
-		rt->pitcs, tnow, hicn_buffer_get_lifetime (b0));
+	      // Make sure the entry is not expired first
+	      if (tnow > hicn_pcs_entry_get_expire_time (pcs_entry))
+		{
+		  // Notify strategy
+		  strategy = hicn_dpo_get_strategy_vft (hicnb0->vft_id);
+		  strategy->hicn_on_interest_timeout (
+		    vnet_buffer (b0)->ip.adj_index[VLIB_TX]);
 
-	      ret = hicn_pcs_pit_insert (rt->pitcs, pcs_entry, &name);
+		  // Release lock on entry - this MUST delete the entry
+		  hicn_pcs_entry_remove_lock (rt->pitcs, pcs_entry);
 
-	      if (PREDICT_FALSE (ret != HICN_ERROR_NONE))
+		  stats.pit_expired_count++;
+
+		  // Forward to strategy node
+		  // TODO this can be simplified by checking directly in the
+		  // pcslookup node!
+		  next0 = HICN_INTEREST_PCSLOOKUP_NEXT_STRATEGY;
+
+		  goto newentry;
+		}
+	      else
 		{
-		  next0 = HICN_INTEREST_PCSLOOKUP_NEXT_ERROR_DROP;
+		  // Next stage for this packet is one of hitpit/cs nodes
+		  next0 = HICN_INTEREST_PCSLOOKUP_NEXT_INTEREST_HITPIT +
+			  hicn_pcs_entry_is_cs (pcs_entry);
+
+		  if (PREDICT_FALSE (ret != HICN_ERROR_NONE))
+		    next0 = HICN_INTEREST_PCSLOOKUP_NEXT_ERROR_DROP;
+
 		  goto end;
 		}
+	    }
+	newentry:
+	  // No entry in PCS. Let's create one now
+	  pcs_entry = hicn_pcs_entry_pit_get (rt->pitcs, tnow,
+					      hicn_buffer_get_lifetime (b0));
 
-	      // Store internal state
-	      ret = hicn_store_internal_state (
-		b0, hicn_pcs_entry_get_index (rt->pitcs, pcs_entry),
-		vnet_buffer (b0)->ip.adj_index[VLIB_TX]);
+	  ret = hicn_pcs_pit_insert (rt->pitcs, pcs_entry, &name);
 
-	      if (PREDICT_FALSE (ret != HICN_ERROR_NONE))
-		{
-		  hicn_pcs_entry_remove_lock (rt->pitcs, pcs_entry);
-		  drop_packet (vm, bi0, &n_left_from, &next0, &to_next,
-			       &next_index, node);
-		  continue;
-		}
+	  if (PREDICT_FALSE (ret != HICN_ERROR_NONE))
+	    {
+	      next0 = HICN_INTEREST_PCSLOOKUP_NEXT_ERROR_DROP;
+	      goto end;
+	    }
 
-	      // Add face
-	      hicn_pcs_entry_pit_add_face (pcs_entry, hicnb0->face_id);
+	  // Store internal state
+	  ret = hicn_store_internal_state (
+	    b0, hicn_pcs_entry_get_index (rt->pitcs, pcs_entry),
+	    vnet_buffer (b0)->ip.adj_index[VLIB_TX]);
+
+	  if (PREDICT_FALSE (ret != HICN_ERROR_NONE))
+	    {
+	      hicn_pcs_entry_remove_lock (rt->pitcs, pcs_entry);
+	      drop_packet (vm, bi0, &n_left_from, &next0, &to_next,
+			   &next_index, node);
+	      continue;
 	    }
 
+	  // Add face
+	  hicn_pcs_entry_pit_add_face (pcs_entry, hicnb0->face_id);
+
 	end:
 	  stats.pkts_interest_count++;
 
diff --git a/hicn-plugin/src/strategy_node.c b/hicn-plugin/src/strategy_node.c
index 9c1a484d6..add5772a4 100644
--- a/hicn-plugin/src/strategy_node.c
+++ b/hicn-plugin/src/strategy_node.c
@@ -155,7 +155,7 @@ hicn_strategy_fn (vlib_main_t *vm, vlib_node_runtime_t *node,
 
 	  if (PREDICT_FALSE (ret != HICN_ERROR_NONE || outfaces_len == 0))
 	    {
-	      drop_packet (vm, bi0, &n_left_from, &next0, &to_next,
+	      drop_packet (vm, bi0, &n_left_to_next, &next0, &to_next,
 			   &next_index, node);
 	      continue;
 	    }