Load Balancer: Use FIB 2.0

This patch fixes load balancer, which was not working
since FIB 2.0.

Two FIB DPO types are defined:
- One for IPv4 GRE
- One for IPv6 GRE

When an AS is created, the plugin automatically uses
the result from the FIB in order to transmit the packet.
Therefore, the packet does not need to visit ip-lookup twice.

The 'bypass' command was removed, as it is now done
automatically using this process.

Change-Id: Ib505ba31bfc67897eaff752821087821c360360a
Signed-off-by: Pierre Pfister <ppfister@cisco.com>

1 files changed, 162 insertions, 124 deletions

diff --git a/plugins/lb-plugin/lb/lb.c b/plugins/lb-plugin/lb/lb.c
index 140c221a438..6af4697e37c 100644
--- a/plugins/lb-plugin/lb/lb.c
+++ b/plugins/lb-plugin/lb/lb.c
@@ -28,6 +28,25 @@ lb_main_t lb_main;
 #define lb_get_writer_lock() do {} while(__sync_lock_test_and_set (lb_main.writer_lock, 1))
 #define lb_put_writer_lock() lb_main.writer_lock[0] = 0
 
+static void lb_as_stack (lb_as_t *as);
+
+
+const static char * const lb_dpo_gre4_ip4[] = { "lb4-gre4" , NULL };
+const static char * const lb_dpo_gre4_ip6[] = { "lb6-gre4" , NULL };
+const static char* const * const lb_dpo_gre4_nodes[DPO_PROTO_NUM] =
+    {
+	[DPO_PROTO_IP4]  = lb_dpo_gre4_ip4,
+	[DPO_PROTO_IP6]  = lb_dpo_gre4_ip6,
+    };
+
+const static char * const lb_dpo_gre6_ip4[] = { "lb4-gre6" , NULL };
+const static char * const lb_dpo_gre6_ip6[] = { "lb6-gre6" , NULL };
+const static char* const * const lb_dpo_gre6_nodes[DPO_PROTO_NUM] =
+    {
+	[DPO_PROTO_IP4]  = lb_dpo_gre6_ip4,
+	[DPO_PROTO_IP6]  = lb_dpo_gre6_ip6,
+    };
+
 u32 lb_hash_time_now(vlib_main_t * vm)
 {
   return (u32) (vlib_time_now(vm) + 10000);
@@ -143,12 +162,12 @@ u8 *format_lb_vip_detailed (u8 * s, va_list * args)
   u32 *as_index;
   pool_foreach(as_index, vip->as_indexes, {
       as = &lbm->ass[*as_index];
-      s = format(s, "%U    %U %d buckets   %d flows  adj:%u %s\n",
+      s = format(s, "%U    %U %d buckets   %d flows  dpo:%u %s\n",
                    format_white_space, indent,
                    format_ip46_address, &as->address, IP46_TYPE_ANY,
                    count[as - lbm->ass],
                    vlib_refcount_get(&lbm->as_refcount, as - lbm->ass),
-                   as->adj_index,
+                   as->dpo.dpoi_index,
                    (as->flags & LB_AS_FLAGS_USED)?"used":" removed");
   });
 
@@ -164,7 +183,6 @@ u8 *format_lb_vip_detailed (u8 * s, va_list * args)
   return s;
 }
 
-
 typedef struct {
   u32 as_index;
   u32 last;
@@ -195,11 +213,18 @@ static void lb_vip_garbage_collection(lb_vip_t *vip)
   pool_foreach(as_index, vip->as_indexes, {
       as = &lbm->ass[*as_index];
       if (!(as->flags & LB_AS_FLAGS_USED) && //Not used
-          clib_u32_loop_gt(now, as->last_used + LB_CONCURRENCY_TIMEOUT) && //Not recently used
-          (vlib_refcount_get(&lbm->as_refcount, as - lbm->ass) == 0)) { //Not referenced
-        pool_put(vip->as_indexes, as_index);
-        pool_put(lbm->ass, as);
-      }
+	  clib_u32_loop_gt(now, as->last_used + LB_CONCURRENCY_TIMEOUT) && //Not recently used
+	  (vlib_refcount_get(&lbm->as_refcount, as - lbm->ass) == 0))
+	{ //Not referenced
+	  fib_entry_child_remove(as->next_hop_fib_entry_index,
+				 as->next_hop_child_index);
+	  fib_table_entry_delete_index(as->next_hop_fib_entry_index,
+				       FIB_SOURCE_RR);
+	  as->next_hop_fib_entry_index = FIB_NODE_INDEX_INVALID;
+
+	  pool_put(vip->as_indexes, as_index);
+	  pool_put(lbm->ass, as);
+	}
   });
 }
 
@@ -449,7 +474,6 @@ next:
   //Update reused ASs
   vec_foreach(ip, to_be_updated) {
     lbm->ass[*ip].flags = LB_AS_FLAGS_USED;
-    lbm->ass[*ip].adj_index = ~0;
   }
   vec_free(to_be_updated);
 
@@ -461,9 +485,36 @@ next:
     as->address = addresses[*ip];
     as->flags = LB_AS_FLAGS_USED;
     as->vip_index = vip_index;
-    as->adj_index = ~0;
     pool_get(vip->as_indexes, as_index);
     *as_index = as - lbm->ass;
+
+    /*
+     * become a child of the FIB entry
+     * so we are informed when its forwarding changes
+     */
+    fib_prefix_t nh = {};
+    if (lb_vip_is_gre4(vip)) {
+	nh.fp_addr.ip4 = as->address.ip4;
+	nh.fp_len = 32;
+	nh.fp_proto = FIB_PROTOCOL_IP4;
+    } else {
+	nh.fp_addr.ip6 = as->address.ip6;
+	nh.fp_len = 128;
+	nh.fp_proto = FIB_PROTOCOL_IP6;
+    }
+
+    as->next_hop_fib_entry_index =
+	fib_table_entry_special_add(0,
+				    &nh,
+				    FIB_SOURCE_RR,
+				    FIB_ENTRY_FLAG_NONE,
+				    ADJ_INDEX_INVALID);
+    as->next_hop_child_index =
+	fib_entry_child_add(as->next_hop_fib_entry_index,
+			    lbm->fib_node_type,
+			    as - lbm->ass);
+
+    lb_as_stack(as);
   }
   vec_free(to_be_added);
 
@@ -535,100 +586,33 @@ int lb_vip_del_ass(u32 vip_index, ip46_address_t *addresses, u32 n)
   return ret;
 }
 
-int lb_as_lookup_bypass(u32 vip_index, ip46_address_t *address, u8 is_disable)
-{
-  /* lb_get_writer_lock(); */
-  /* lb_main_t *lbm = &lb_main; */
-  /* u32 as_index; */
-  /* lb_as_t *as; */
-  /* lb_vip_t *vip; */
-
-  /* if (!(vip = lb_vip_get_by_index(vip_index)) || */
-  /*     lb_as_find_index_vip(vip, address, &as_index)) { */
-  /*   lb_put_writer_lock(); */
-  /*   return VNET_API_ERROR_NO_SUCH_ENTRY; */
-  /* } */
-
-  /* as = &lbm->ass[as_index]; */
-
-  /* if (is_disable) { */
-  /*   as->adj_index = ~0; */
-  /* } else if (lb_vip_is_gre4(vip)) { */
-  /*   uword *p = ip4_get_route (&ip4_main, 0, 0, as->address.ip4.as_u8, 32); */
-  /*   if (p == 0) { */
-  /*     lb_put_writer_lock(); */
-  /*     return VNET_API_ERROR_NO_SUCH_ENTRY; */
-  /*   } */
-  /*   u32 ai = (u32)p[0]; */
-  /*   ip_lookup_main_t *lm4 = &ip4_main.lookup_main; */
-  /*   ip_adjacency_t *adj4 = ip_get_adjacency (lm4, ai); */
-  /*   if (adj4->lookup_next_index != IP_LOOKUP_NEXT_REWRITE) { */
-  /*     lb_put_writer_lock(); */
-  /*     return VNET_API_ERROR_INCORRECT_ADJACENCY_TYPE; */
-  /*   } */
-
-  /*   as->adj_index = ai; */
-  /* } else { */
-  /*   u32 ai = ip6_get_route (&ip6_main, 0, 0, &as->address.ip6, 128); */
-  /*   if (ai == 0) { */
-  /*     lb_put_writer_lock(); */
-  /*     return VNET_API_ERROR_NO_SUCH_ENTRY; */
-  /*   } */
-
-  /*   ip_lookup_main_t *lm6 = &ip6_main.lookup_main; */
-  /*   ip_adjacency_t *adj6 = ip_get_adjacency (lm6, ai); */
-  /*   if (adj6->lookup_next_index != IP_LOOKUP_NEXT_REWRITE) { */
-  /*     lb_put_writer_lock(); */
-  /*     return VNET_API_ERROR_INCORRECT_ADJACENCY_TYPE; */
-  /*   } */
-
-  /*   as->adj_index = ai; */
-  /* } */
-  /* lb_put_writer_lock(); */
-  return 0;
-}
-
-
 /**
  * Add the VIP adjacency to the ip4 or ip6 fib
  */
 static void lb_vip_add_adjacency(lb_main_t *lbm, lb_vip_t *vip)
 {
-  /* ip_adjacency_t adj; */
-  /* //Adjacency */
-  /* memset (&adj, 0, sizeof (adj)); */
-  /* adj.explicit_fib_index = ~0; */
-  /* lb_adj_data_t *ad = (lb_adj_data_t *) &adj.opaque; */
-  /* ad->vip_index = vip - lbm->vips; */
-
-  /* ASSERT (lbm->writer_lock[0]); //This must be called with the lock owned */
-  /* u32 lookup_next_index = lbm->ip_lookup_next_index[vip->type]; */
-
-  /* if (lb_vip_is_ip4(vip)) { */
-  /*   adj.lookup_next_index = lookup_next_index; */
-  /*   ip4_add_del_route_args_t route_args = {}; */
-  /*   ip4_main_t *im4 = &ip4_main; */
-  /*   route_args.table_index_or_table_id = 0; */
-  /*   route_args.flags = IP4_ROUTE_FLAG_ADD; */
-  /*   route_args.dst_address = vip->prefix.ip4; */
-  /*   route_args.dst_address_length = vip->plen - 96; */
-  /*   route_args.adj_index = ~0; */
-  /*   route_args.add_adj = &adj; */
-  /*   route_args.n_add_adj = 1; */
-  /*   ip4_add_del_route (im4, &route_args); */
-  /* } else { */
-  /*   adj.lookup_next_index = lookup_next_index; */
-  /*   ip6_add_del_route_args_t route_args = {}; */
-  /*   ip6_main_t *im6 = &ip6_main; */
-  /*   route_args.table_index_or_table_id = 0; */
-  /*   route_args.flags = IP6_ROUTE_FLAG_ADD; */
-  /*   route_args.dst_address = vip->prefix.ip6; */
-  /*   route_args.dst_address_length = vip->plen; */
-  /*   route_args.adj_index = ~0; */
-  /*   route_args.add_adj = &adj; */
-  /*   route_args.n_add_adj = 1; */
-  /*   ip6_add_del_route (im6, &route_args); */
-  /* } */
+  dpo_proto_t proto = 0;
+  dpo_id_t dpo = DPO_NULL;
+  fib_prefix_t pfx = {};
+  if (lb_vip_is_ip4(vip)) {
+      pfx.fp_addr.ip4 = vip->prefix.ip4;
+      pfx.fp_len = vip->plen - 96;
+      pfx.fp_proto = FIB_PROTOCOL_IP4;
+      proto = DPO_PROTO_IP4;
+  } else {
+      pfx.fp_addr.ip6 = vip->prefix.ip6;
+      pfx.fp_len = vip->plen;
+      pfx.fp_proto = FIB_PROTOCOL_IP6;
+      proto = DPO_PROTO_IP6;
+  }
+  dpo_set(&dpo, lb_vip_is_gre4(vip)?lbm->dpo_gre4_type:lbm->dpo_gre6_type,
+      proto, vip - lbm->vips);
+  fib_table_entry_special_dpo_add(0,
+				  &pfx,
+				  FIB_SOURCE_PLUGIN_HI,
+				  FIB_ENTRY_FLAG_EXCLUSIVE,
+				  &dpo);
+  dpo_reset(&dpo);
 }
 
 /**
@@ -636,30 +620,17 @@ static void lb_vip_add_adjacency(lb_main_t *lbm, lb_vip_t *vip)
  */
 static void lb_vip_del_adjacency(lb_main_t *lbm, lb_vip_t *vip)
 {
-  /* ASSERT (lbm->writer_lock[0]); //This must be called with the lock owned */
-  /* if (lb_vip_is_ip4(vip)) { */
-  /*   ip4_main_t *im4 = &ip4_main; */
-  /*   ip4_add_del_route_args_t route_args = {}; */
-  /*   route_args.table_index_or_table_id = 0; */
-  /*   route_args.flags = IP4_ROUTE_FLAG_DEL; */
-  /*   route_args.dst_address = vip->prefix.ip4; */
-  /*   route_args.dst_address_length = vip->plen - 96; */
-  /*   route_args.adj_index = ~0; */
-  /*   route_args.add_adj = NULL; */
-  /*   route_args.n_add_adj = 0; */
-  /*   ip4_add_del_route (im4, &route_args); */
-  /* } else { */
-  /*   ip6_main_t *im6 = &ip6_main; */
-  /*   ip6_add_del_route_args_t route_args = {}; */
-  /*   route_args.table_index_or_table_id = 0; */
-  /*   route_args.flags = IP6_ROUTE_FLAG_DEL; */
-  /*   route_args.dst_address = vip->prefix.ip6; */
-  /*   route_args.dst_address_length = vip->plen; */
-  /*   route_args.adj_index = ~0; */
-  /*   route_args.add_adj = NULL; */
-  /*   route_args.n_add_adj = 0; */
-  /*   ip6_add_del_route (im6, &route_args); */
-  /* } */
+  fib_prefix_t pfx = {};
+  if (lb_vip_is_ip4(vip)) {
+      pfx.fp_addr.ip4 = vip->prefix.ip4;
+      pfx.fp_len = vip->plen - 96;
+      pfx.fp_proto = FIB_PROTOCOL_IP4;
+  } else {
+      pfx.fp_addr.ip6 = vip->prefix.ip6;
+      pfx.fp_len = vip->plen;
+      pfx.fp_proto = FIB_PROTOCOL_IP6;
+  }
+  fib_table_entry_special_remove(0, &pfx, FIB_SOURCE_PLUGIN_HI);
 }
 
 int lb_vip_add(ip46_address_t *prefix, u8 plen, lb_vip_type_t type, u32 new_length, u32 *vip_index)
@@ -766,12 +737,76 @@ vlib_plugin_register (vlib_main_t * vm,
   return error;
 }
 
+
+u8 *format_lb_dpo (u8 * s, va_list * va)
+{
+  index_t index = va_arg (*va, index_t);
+  CLIB_UNUSED(u32 indent) = va_arg (*va, u32);
+  lb_main_t *lbm = &lb_main;
+  lb_vip_t *vip = pool_elt_at_index (lbm->vips, index);
+  return format (s, "%U", format_lb_vip, vip);
+}
+
+static void lb_dpo_lock (dpo_id_t *dpo) {}
+static void lb_dpo_unlock (dpo_id_t *dpo) {}
+
+static fib_node_t *
+lb_fib_node_get_node (fib_node_index_t index)
+{
+  lb_main_t *lbm = &lb_main;
+  lb_as_t *as = pool_elt_at_index (lbm->ass, index);
+  return (&as->fib_node);
+}
+
+static void
+lb_fib_node_last_lock_gone (fib_node_t *node)
+{
+}
+
+static lb_as_t *
+lb_as_from_fib_node (fib_node_t *node)
+{
+  return ((lb_as_t*)(((char*)node) -
+      STRUCT_OFFSET_OF(lb_as_t, fib_node)));
+}
+
+static void
+lb_as_stack (lb_as_t *as)
+{
+  lb_main_t *lbm = &lb_main;
+  lb_vip_t *vip = &lbm->vips[as->vip_index];
+  dpo_stack(lb_vip_is_gre4(vip)?lbm->dpo_gre4_type:lbm->dpo_gre6_type,
+	    lb_vip_is_ip4(vip)?DPO_PROTO_IP4:DPO_PROTO_IP6,
+	    &as->dpo,
+	    fib_entry_contribute_ip_forwarding(
+		as->next_hop_fib_entry_index));
+}
+
+static fib_node_back_walk_rc_t
+lb_fib_node_back_walk_notify (fib_node_t *node,
+			       fib_node_back_walk_ctx_t *ctx)
+{
+    lb_as_stack(lb_as_from_fib_node(node));
+    return (FIB_NODE_BACK_WALK_CONTINUE);
+}
+
 clib_error_t *
 lb_init (vlib_main_t * vm)
 {
   vlib_thread_main_t *tm = vlib_get_thread_main ();
   lb_main_t *lbm = &lb_main;
   lb_as_t *default_as;
+  fib_node_vft_t lb_fib_node_vft = {
+      .fnv_get = lb_fib_node_get_node,
+      .fnv_last_lock = lb_fib_node_last_lock_gone,
+      .fnv_back_walk = lb_fib_node_back_walk_notify,
+  };
+  dpo_vft_t lb_vft = {
+      .dv_lock = lb_dpo_lock,
+      .dv_unlock = lb_dpo_unlock,
+      .dv_format = format_lb_dpo,
+  };
+
   lbm->vips = 0;
   lbm->per_cpu = 0;
   vec_validate(lbm->per_cpu, tm->n_vlib_mains - 1);
@@ -782,6 +817,9 @@ lb_init (vlib_main_t * vm)
   lbm->ip4_src_address.as_u32 = 0xffffffff;
   lbm->ip6_src_address.as_u64[0] = 0xffffffffffffffffL;
   lbm->ip6_src_address.as_u64[1] = 0xffffffffffffffffL;
+  lbm->dpo_gre4_type = dpo_register_new_type(&lb_vft, lb_dpo_gre4_nodes);
+  lbm->dpo_gre6_type = dpo_register_new_type(&lb_vft, lb_dpo_gre6_nodes);
+  lbm->fib_node_type = fib_node_register_new_type(&lb_fib_node_vft);
 
   //Init AS reference counters
   vlib_refcount_init(&lbm->as_refcount);
@@ -790,7 +828,7 @@ lb_init (vlib_main_t * vm)
   lbm->ass = 0;
   pool_get(lbm->ass, default_as);
   default_as->flags = 0;
-  default_as->adj_index = ~0;
+  default_as->dpo.dpoi_next_node = LB_NEXT_DROP;
   default_as->vip_index = ~0;
   default_as->address.ip6.as_u64[0] = 0xffffffffffffffffL;
   default_as->address.ip6.as_u64[1] = 0xffffffffffffffffL;