MAP pre-resolve - use FIB to track pre-resolved next-hop

Change-Id: I9ea16881caf7aee57f0daf4ac2e8b82c672f87e9
Signed-off-by: Neale Ranns <nranns@cisco.com>

4 files changed, 190 insertions, 55 deletions

diff --git a/src/vnet/map/ip4_map.c b/src/vnet/map/ip4_map.c
index 9fd10f62..2be9ad37 100644
--- a/src/vnet/map/ip4_map.c
+++ b/src/vnet/map/ip4_map.c
@@ -173,18 +173,10 @@ static_always_inline bool
 ip4_map_ip6_lookup_bypass (vlib_buffer_t * p0, ip4_header_t * ip)
 {
 #ifdef MAP_SKIP_IP6_LOOKUP
-  map_main_t *mm = &map_main;
-  u32 adj_index0 = mm->adj6_index;
-  if (adj_index0 > 0)
+  if (FIB_NODE_INDEX_INVALID != pre_resolved[FIB_PROTOCOL_IP6].fei)
     {
-      ip_lookup_main_t *lm6 = &ip6_main.lookup_main;
-      ip_adjacency_t *adj = ip_get_adjacency (lm6, mm->adj6_index);
-      if (adj->n_adj > 1)
-	{
-	  u32 hash_c0 = ip4_compute_flow_hash (ip, IP_FLOW_HASH_DEFAULT);
-	  adj_index0 += (hash_c0 & (adj->n_adj - 1));
-	}
-      vnet_buffer (p0)->ip.adj_index[VLIB_TX] = adj_index0;
+      vnet_buffer (p0)->ip.adj_index[VLIB_TX] =
+	pre_resolved[FIB_PROTOCOL_IP6].dpo.dpoi_index;
       return (true);
     }
 #endif
@@ -773,7 +765,7 @@ VLIB_REGISTER_NODE(ip4_map_node) = {
   .next_nodes = {
     [IP4_MAP_NEXT_IP6_LOOKUP] = "ip6-lookup",
 #ifdef MAP_SKIP_IP6_LOOKUP
-    [IP4_MAP_NEXT_IP6_REWRITE] = "ip6-rewrite",
+    [IP4_MAP_NEXT_IP6_REWRITE] = "ip6-load-balance",
 #endif
     [IP4_MAP_NEXT_IP4_FRAGMENT] = "ip4-frag",
     [IP4_MAP_NEXT_IP6_FRAGMENT] = "ip6-frag",
diff --git a/src/vnet/map/ip6_map.c b/src/vnet/map/ip6_map.c
index d2945059..f7eb768f 100644
--- a/src/vnet/map/ip6_map.c
+++ b/src/vnet/map/ip6_map.c
@@ -151,18 +151,10 @@ static_always_inline bool
 ip6_map_ip4_lookup_bypass (vlib_buffer_t * p0, ip4_header_t * ip)
 {
 #ifdef MAP_SKIP_IP6_LOOKUP
-  map_main_t *mm = &map_main;
-  u32 adj_index0 = mm->adj4_index;
-  if (adj_index0 > 0)
+  if (FIB_NODE_INDEX_INVALID != pre_resolved[FIB_PROTOCOL_IP4].fei)
     {
-      ip_lookup_main_t *lm4 = &ip4_main.lookup_main;
-      ip_adjacency_t *adj = ip_get_adjacency (lm4, mm->adj4_index);
-      if (adj->n_adj > 1)
-	{
-	  u32 hash_c0 = ip4_compute_flow_hash (ip, IP_FLOW_HASH_DEFAULT);
-	  adj_index0 += (hash_c0 & (adj->n_adj - 1));
-	}
-      vnet_buffer (p0)->ip.adj_index[VLIB_TX] = adj_index0;
+      vnet_buffer (p0)->ip.adj_index[VLIB_TX] =
+	pre_resolved[FIB_PROTOCOL_IP4].dpo.dpoi_index;
       return (true);
     }
 #endif
@@ -1195,7 +1187,7 @@ VLIB_REGISTER_NODE(ip6_map_node) = {
   .next_nodes = {
     [IP6_MAP_NEXT_IP4_LOOKUP] = "ip4-lookup",
 #ifdef MAP_SKIP_IP6_LOOKUP
-    [IP6_MAP_NEXT_IP4_REWRITE] = "ip4-rewrite",
+    [IP6_MAP_NEXT_IP4_REWRITE] = "ip4-load-balance",
 #endif
     [IP6_MAP_NEXT_IP6_REASS] = "ip6-map-ip6-reass",
     [IP6_MAP_NEXT_IP4_REASS] = "ip6-map-ip4-reass",
diff --git a/src/vnet/map/map.c b/src/vnet/map/map.c
index a2d28118..6823a46e 100644
--- a/src/vnet/map/map.c
+++ b/src/vnet/map/map.c
@@ -41,6 +41,7 @@ crc_u32 (u32 data, u32 value)
 }
 #endif
 
+
 /*
  * This code supports the following MAP modes:
  *
@@ -437,23 +438,141 @@ map_add_del_psid (u32 map_domain_index, u16 psid, ip6_address_t * tep,
 }
 
 #ifdef MAP_SKIP_IP6_LOOKUP
+/**
+ * Pre-resolvd per-protocol global next-hops
+ */
+map_main_pre_resolved_t pre_resolved[FIB_PROTOCOL_MAX];
+
 static void
-map_pre_resolve (ip4_address_t * ip4, ip6_address_t * ip6)
+map_pre_resolve_init (map_main_pre_resolved_t * pr)
 {
-  map_main_t *mm = &map_main;
-  ip6_main_t *im6 = &ip6_main;
+  pr->fei = FIB_NODE_INDEX_INVALID;
+  fib_node_init (&pr->node, FIB_NODE_TYPE_MAP_E);
+}
+
+static u8 *
+format_map_pre_resolve (u8 * s, va_list ap)
+{
+  map_main_pre_resolved_t *pr = va_arg (ap, map_main_pre_resolved_t *);
+
+  if (FIB_NODE_INDEX_INVALID != pr->fei)
+    {
+      fib_prefix_t pfx;
+
+      fib_entry_get_prefix (pr->fei, &pfx);
+
+      return (format (s, "%U (%u)",
+		      format_ip46_address, &pfx.fp_addr, IP46_TYPE_ANY,
+		      pr->dpo.dpoi_index));
+    }
+  else
+    {
+      return (format (s, "un-set"));
+    }
+}
+
+
+/**
+ * Function definition to inform the FIB node that its last lock has gone.
+ */
+static void
+map_last_lock_gone (fib_node_t * node)
+{
+  /*
+   * The MAP is a root of the graph. As such
+   * it never has children and thus is never locked.
+   */
+  ASSERT (0);
+}
+
+static map_main_pre_resolved_t *
+map_from_fib_node (fib_node_t * node)
+{
+#if (CLIB_DEBUG > 0)
+  ASSERT (FIB_NODE_TYPE_MAP_E == node->fn_type);
+#endif
+  return ((map_main_pre_resolved_t *)
+	  (((char *) node) -
+	   STRUCT_OFFSET_OF (map_main_pre_resolved_t, node)));
+}
+
+static void
+map_stack (map_main_pre_resolved_t * pr)
+{
+  const dpo_id_t *dpo;
 
-  if (ip6->as_u64[0] != 0 || ip6->as_u64[1] != 0)
+  dpo = fib_entry_contribute_ip_forwarding (pr->fei);
+
+  dpo_copy (&pr->dpo, dpo);
+}
+
+/**
+ * Function definition to backwalk a FIB node
+ */
+static fib_node_back_walk_rc_t
+map_back_walk (fib_node_t * node, fib_node_back_walk_ctx_t * ctx)
+{
+  map_stack (map_from_fib_node (node));
+
+  return (FIB_NODE_BACK_WALK_CONTINUE);
+}
+
+/**
+ * Function definition to get a FIB node from its index
+ */
+static fib_node_t *
+map_fib_node_get (fib_node_index_t index)
+{
+  return (&pre_resolved[index].node);
+}
+
+/*
+ * Virtual function table registered by MPLS GRE tunnels
+ * for participation in the FIB object graph.
+ */
+const static fib_node_vft_t map_vft = {
+  .fnv_get = map_fib_node_get,
+  .fnv_last_lock = map_last_lock_gone,
+  .fnv_back_walk = map_back_walk,
+};
+
+static void
+map_fib_resolve (map_main_pre_resolved_t * pr,
+		 fib_protocol_t proto, u8 len, const ip46_address_t * addr)
+{
+  fib_prefix_t pfx = {
+    .fp_proto = proto,
+    .fp_len = len,
+    .fp_addr = *addr,
+  };
+
+  pr->fei = fib_table_entry_special_add (0,	// default fib
+					 &pfx,
+					 FIB_SOURCE_RR,
+					 FIB_ENTRY_FLAG_NONE,
+					 ADJ_INDEX_INVALID);
+  pr->sibling = fib_entry_child_add (pr->fei, FIB_NODE_TYPE_MAP_E, proto);
+  map_stack (pr);
+}
+
+static void
+map_pre_resolve (ip4_address_t * ip4, ip6_address_t * ip6)
+{
+  if (ip6 && (ip6->as_u64[0] != 0 || ip6->as_u64[1] != 0))
     {
-      // FIXME NOT an ADJ
-      mm->adj6_index = ip6_fib_table_fwding_lookup (im6, 0, ip6);
-      clib_warning ("FIB lookup results in: %u", mm->adj6_index);
+      ip46_address_t addr = {
+	.ip6 = *ip6,
+      };
+      map_fib_resolve (&pre_resolved[FIB_PROTOCOL_IP6],
+		       FIB_PROTOCOL_IP6, 128, &addr);
     }
-  if (ip4->as_u32 != 0)
+  if (ip4 && (ip4->as_u32 != 0))
     {
-      // FIXME NOT an ADJ
-      mm->adj4_index = ip4_fib_table_lookup_lb (0, ip4);
-      clib_warning ("FIB lookup results in: %u", mm->adj4_index);
+      ip46_address_t addr = {
+	.ip4 = *ip4,
+      };
+      map_fib_resolve (&pre_resolved[FIB_PROTOCOL_IP4],
+		       FIB_PROTOCOL_IP4, 32, &addr);
     }
 }
 #endif
@@ -695,9 +814,8 @@ map_pre_resolve_command_fn (vlib_main_t * vm,
 			    vlib_cli_command_t * cmd)
 {
   unformat_input_t _line_input, *line_input = &_line_input;
-  ip4_address_t ip4nh;
-  ip6_address_t ip6nh;
-  map_main_t *mm = &map_main;
+  ip4_address_t ip4nh, *p_v4 = NULL;
+  ip6_address_t ip6nh, *p_v6 = NULL;
   clib_error_t *error = NULL;
 
   memset (&ip4nh, 0, sizeof (ip4nh));
@@ -710,10 +828,10 @@ map_pre_resolve_command_fn (vlib_main_t * vm,
   while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
     {
       if (unformat (line_input, "ip4-nh %U", unformat_ip4_address, &ip4nh))
-	mm->preresolve_ip4 = ip4nh;
+	p_v4 = &ip4nh;
       else
 	if (unformat (line_input, "ip6-nh %U", unformat_ip6_address, &ip6nh))
-	mm->preresolve_ip6 = ip6nh;
+	p_v6 = &ip6nh;
       else
 	{
 	  error = clib_error_return (0, "unknown input `%U'",
@@ -722,7 +840,7 @@ map_pre_resolve_command_fn (vlib_main_t * vm,
 	}
     }
 
-  map_pre_resolve (&ip4nh, &ip6nh);
+  map_pre_resolve (p_v4, p_v6);
 
 done:
   unformat_free (line_input);
@@ -1113,9 +1231,10 @@ show_map_stats_command_fn (vlib_main_t * vm, unformat_input_t * input,
 
 #if MAP_SKIP_IP6_LOOKUP
   vlib_cli_output (vm,
-		   "MAP pre-resolve: IP6 next-hop: %U (%u), IP4 next-hop: %U (%u)\n",
-		   format_ip6_address, &mm->preresolve_ip6, mm->adj6_index,
-		   format_ip4_address, &mm->preresolve_ip4, mm->adj4_index);
+		   "MAP pre-resolve: IP6 next-hop: %U, IP4 next-hop: %U\n",
+		   format_map_pre_resolve, &pre_resolved[FIB_PROTOCOL_IP6],
+		   format_map_pre_resolve, &pre_resolved[FIB_PROTOCOL_IP4]);
+
 #endif
 
   if (mm->tc_copy)
@@ -2180,10 +2299,12 @@ map_init (vlib_main_t * vm)
   mm->vlib_main = vm;
 
 #ifdef MAP_SKIP_IP6_LOOKUP
-  memset (&mm->preresolve_ip4, 0, sizeof (mm->preresolve_ip4));
-  memset (&mm->preresolve_ip6, 0, sizeof (mm->preresolve_ip6));
-  mm->adj4_index = 0;
-  mm->adj6_index = 0;
+  fib_protocol_t proto;
+
+  FOR_EACH_FIB_PROTOCOL (proto)
+  {
+    map_pre_resolve_init (&pre_resolved[proto]);
+  }
 #endif
 
   /* traffic class */
@@ -2238,6 +2359,9 @@ map_init (vlib_main_t * vm)
   mm->ip6_reass_fifo_last = MAP_REASS_INDEX_NONE;
   map_ip6_reass_reinit (NULL, NULL);
 
+#ifdef MAP_SKIP_IP6_LOOKUP
+  fib_node_register_type (FIB_NODE_TYPE_MAP_E, &map_vft);
+#endif
   map_dpo_module_init ();
 
   return 0;
diff --git a/src/vnet/map/map.h b/src/vnet/map/map.h
index f446b739..616d42c0 100644
--- a/src/vnet/map/map.h
+++ b/src/vnet/map/map.h
@@ -198,6 +198,40 @@ typedef struct {
   map_ip6_fragment_t fragments[MAP_IP6_REASS_MAX_FRAGMENTS_PER_REASSEMBLY];
 } map_ip6_reass_t;
 
+#ifdef MAP_SKIP_IP6_LOOKUP
+/**
+ * A pre-resolved next-hop
+ */
+typedef struct map_main_pre_resolved_t_
+{
+  /**
+   * Linkage into the FIB graph
+   */
+  fib_node_t node;
+
+  /**
+   * The FIB entry index of the next-hop
+   */
+  fib_node_index_t fei;
+
+  /**
+   * This object sibling index on the FIB entry's child dependency list
+   */
+  u32 sibling;
+
+  /**
+   * The Load-balance object index to use to forward
+   */
+  dpo_id_t dpo;
+} map_main_pre_resolved_t;
+
+/**
+ * Pre-resolved next hops for v4 and v6. Why these are global and not
+ * per-domain is beyond me.
+ */
+extern map_main_pre_resolved_t pre_resolved[FIB_PROTOCOL_MAX];
+#endif
+
 typedef struct {
   /* pool of MAP domains */
   map_domain_t *domains;
@@ -207,13 +241,6 @@ typedef struct {
   vlib_combined_counter_main_t *domain_counters;
   volatile u32 *counter_lock;
 
-#ifdef MAP_SKIP_IP6_LOOKUP
-  /* pre-presolve */
-  u32 adj6_index, adj4_index;
-  ip4_address_t preresolve_ip4;
-  ip6_address_t preresolve_ip6;
-#endif
-
   /* Traffic class: zero, copy (~0) or fixed value */
   u8 tc;
   bool tc_copy;