BFD-FIB interactions

- single-hop BFD: attach a delegate to the appropriate adjacency
- multi-hop BFD [not supported yet]: attach a delegate to the FIB entry.

adjacency/fib_entry state tracks the BFD session state. when the state is down the object does not contribute forwarding hence and hence dependent objects will not use it.
For example, if a route is ECMP via two adjacencies and one of them is BFD down, then only the other is used to forward (i.e. we don't drop half the traffic).

Change-Id: I0ef53e20e73b067001a132cd0a3045408811a822
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 522 insertions, 0 deletions

diff --git a/src/vnet/fib/fib_test.c b/src/vnet/fib/fib_test.c
index 92141ddfce1..3c9b8a38fe1 100644
--- a/src/vnet/fib/fib_test.c
+++ b/src/vnet/fib/fib_test.c
@@ -24,6 +24,7 @@
 #include <vnet/dpo/drop_dpo.h>
 #include <vnet/dpo/receive_dpo.h>
 #include <vnet/dpo/ip_null_dpo.h>
+#include <vnet/bfd/bfd_main.h>
 
 #include <vnet/mpls/mpls.h>
 
@@ -33,6 +34,11 @@
 #include <vnet/fib/fib_node_list.h>
 #include <vnet/fib/fib_urpf_list.h>
 
+/*
+ * Add debugs for passing tests
+ */
+static int fib_test_do_debug;
+
 #define FIB_TEST_I(_cond, _comment, _args...)			\
 ({								\
     int _evald = (_cond);					\
@@ -40,6 +46,9 @@
 	fformat(stderr, "FAIL:%d: " _comment "\n",		\
 		__LINE__, ##_args);				\
     } else {							\
+	if (fib_test_do_debug)                                  \
+            fformat(stderr, "PASS:%d: " _comment "\n",          \
+                    __LINE__, ##_args);				\
     }								\
     _evald;							\
 })
@@ -6735,6 +6744,509 @@ fib_test_walk (void)
     return (0);
 }
 
+/*
+ * declaration of the otherwise static callback functions
+ */
+void fib_bfd_notify (bfd_listen_event_e event,
+                     const bfd_session_t *session);
+void adj_bfd_notify (bfd_listen_event_e event,
+                     const bfd_session_t *session);
+
+/**
+ * Test BFD session interaction with FIB
+ */
+static int
+fib_test_bfd (void)
+{
+    fib_node_index_t fei;
+    test_main_t *tm;
+    int n_feis;
+
+    /* via 10.10.10.1 */
+    ip46_address_t nh_10_10_10_1 = {
+        .ip4.as_u32 = clib_host_to_net_u32(0x0a0a0a01),
+    };
+    /* via 10.10.10.2 */
+    ip46_address_t nh_10_10_10_2 = {
+        .ip4.as_u32 = clib_host_to_net_u32(0x0a0a0a02),
+    };
+    /* via 10.10.10.10 */
+    ip46_address_t nh_10_10_10_10 = {
+        .ip4.as_u32 = clib_host_to_net_u32(0x0a0a0a0a),
+    };
+    n_feis = fib_entry_pool_size();
+
+    tm = &test_main;
+
+    /*
+     * add interface routes. we'll assume this works. it's tested elsewhere
+     */
+    fib_prefix_t pfx_10_10_10_10_s_24 = {
+        .fp_len = 24,
+        .fp_proto = FIB_PROTOCOL_IP4,
+        .fp_addr = nh_10_10_10_10,
+    };
+
+    fib_table_entry_update_one_path(0, &pfx_10_10_10_10_s_24,
+                                    FIB_SOURCE_INTERFACE,
+                                    (FIB_ENTRY_FLAG_CONNECTED |
+                                     FIB_ENTRY_FLAG_ATTACHED),
+                                    FIB_PROTOCOL_IP4,
+                                    NULL,
+                                    tm->hw[0]->sw_if_index,
+                                    ~0, // invalid fib index
+                                    1, // weight
+                                    NULL,
+                                    FIB_ROUTE_PATH_FLAG_NONE);
+
+    fib_prefix_t pfx_10_10_10_10_s_32 = {
+        .fp_len = 32,
+        .fp_proto = FIB_PROTOCOL_IP4,
+        .fp_addr = nh_10_10_10_10,
+    };
+    fib_table_entry_update_one_path(0, &pfx_10_10_10_10_s_32,
+                                    FIB_SOURCE_INTERFACE,
+                                    (FIB_ENTRY_FLAG_CONNECTED |
+                                     FIB_ENTRY_FLAG_LOCAL),
+                                    FIB_PROTOCOL_IP4,
+                                    NULL,
+                                    tm->hw[0]->sw_if_index,
+                                    ~0, // invalid fib index
+                                    1, // weight
+                                    NULL,
+                                    FIB_ROUTE_PATH_FLAG_NONE);
+
+    /*
+     * A BFD session via a neighbour we do not yet know
+     */
+    bfd_session_t bfd_10_10_10_1 = {
+        .udp = {
+            .key = {
+                .fib_index = 0,
+                .peer_addr = nh_10_10_10_1,
+            },
+        },
+        .hop_type = BFD_HOP_TYPE_MULTI,
+        .local_state = BFD_STATE_init,
+    };
+
+    fib_bfd_notify (BFD_LISTEN_EVENT_CREATE, &bfd_10_10_10_1);
+
+    /*
+     * A new entry will be created that forwards via the adj
+     */
+    adj_index_t ai_10_10_10_1 = adj_nbr_add_or_lock(FIB_PROTOCOL_IP4,
+                                                    VNET_LINK_IP4,
+                                                    &nh_10_10_10_1,
+                                                    tm->hw[0]->sw_if_index);
+    fib_prefix_t pfx_10_10_10_1_s_32 = {
+        .fp_addr = nh_10_10_10_1,
+        .fp_len = 32,
+        .fp_proto = FIB_PROTOCOL_IP4,
+    };
+    fib_test_lb_bucket_t adj_o_10_10_10_1 = {
+        .type = FT_LB_ADJ,
+        .adj = {
+            .adj = ai_10_10_10_1,
+        },
+    };
+
+    fei = fib_table_lookup_exact_match(0, &pfx_10_10_10_1_s_32);
+    FIB_TEST(fib_test_validate_entry(fei,
+                                     FIB_FORW_CHAIN_TYPE_UNICAST_IP4,
+                                     1,
+                                     &adj_o_10_10_10_1),
+             "BFD sourced %U via %U",
+             format_fib_prefix, &pfx_10_10_10_1_s_32,
+             format_ip_adjacency, ai_10_10_10_1, FORMAT_IP_ADJACENCY_NONE);
+
+    /*
+     * Delete the BFD session. Expect the fib_entry to be removed
+     */
+    fib_bfd_notify (BFD_LISTEN_EVENT_DELETE, &bfd_10_10_10_1);
+
+    fei = fib_table_lookup_exact_match(0, &pfx_10_10_10_1_s_32);
+    FIB_TEST(FIB_NODE_INDEX_INVALID == fei,
+             "BFD sourced %U removed",
+             format_fib_prefix, &pfx_10_10_10_1_s_32);
+
+    /*
+     * Add the BFD source back
+     */
+    fib_bfd_notify (BFD_LISTEN_EVENT_CREATE, &bfd_10_10_10_1);
+
+    /*
+     * source the entry via the ADJ fib
+     */
+    fei = fib_table_entry_update_one_path(0,
+                                          &pfx_10_10_10_1_s_32,
+                                          FIB_SOURCE_ADJ,
+                                          FIB_ENTRY_FLAG_ATTACHED,
+                                          FIB_PROTOCOL_IP4,
+                                          &nh_10_10_10_1,
+                                          tm->hw[0]->sw_if_index,
+                                          ~0, // invalid fib index
+                                          1,
+                                          NULL,
+                                          FIB_ROUTE_PATH_FLAG_NONE);
+
+    /*
+     * Delete the BFD session. Expect the fib_entry to remain
+     */
+    fib_bfd_notify (BFD_LISTEN_EVENT_DELETE, &bfd_10_10_10_1);
+
+    fei = fib_table_lookup_exact_match(0, &pfx_10_10_10_1_s_32);
+    FIB_TEST(fib_test_validate_entry(fei,
+                                     FIB_FORW_CHAIN_TYPE_UNICAST_IP4,
+                                     1,
+                                     &adj_o_10_10_10_1),
+             "BFD sourced %U remains via %U",
+             format_fib_prefix, &pfx_10_10_10_1_s_32,
+             format_ip_adjacency, ai_10_10_10_1, FORMAT_IP_ADJACENCY_NONE);
+
+    /*
+     * Add the BFD source back
+     */
+    fib_bfd_notify (BFD_LISTEN_EVENT_CREATE, &bfd_10_10_10_1);
+
+    /*
+     * Create another ADJ FIB
+     */
+    fib_prefix_t pfx_10_10_10_2_s_32 = {
+        .fp_addr = nh_10_10_10_2,
+        .fp_len = 32,
+        .fp_proto = FIB_PROTOCOL_IP4,
+    };
+    fib_table_entry_update_one_path(0,
+                                    &pfx_10_10_10_2_s_32,
+                                    FIB_SOURCE_ADJ,
+                                    FIB_ENTRY_FLAG_ATTACHED,
+                                    FIB_PROTOCOL_IP4,
+                                    &nh_10_10_10_2,
+                                    tm->hw[0]->sw_if_index,
+                                    ~0, // invalid fib index
+                                    1,
+                                    NULL,
+                                    FIB_ROUTE_PATH_FLAG_NONE);
+    /*
+     * A BFD session for the new ADJ FIB
+     */
+    bfd_session_t bfd_10_10_10_2 = {
+        .udp = {
+            .key = {
+                .fib_index = 0,
+                .peer_addr = nh_10_10_10_2,
+            },
+        },
+        .hop_type = BFD_HOP_TYPE_MULTI,
+        .local_state = BFD_STATE_init,
+    };
+
+    fib_bfd_notify (BFD_LISTEN_EVENT_CREATE, &bfd_10_10_10_2);
+
+    /*
+     * remove the adj-fib source whilst the session is present
+     * then add it back
+     */
+    fib_table_entry_delete(0, &pfx_10_10_10_2_s_32, FIB_SOURCE_ADJ);
+    fib_table_entry_update_one_path(0,
+                                    &pfx_10_10_10_2_s_32,
+                                    FIB_SOURCE_ADJ,
+                                    FIB_ENTRY_FLAG_ATTACHED,
+                                    FIB_PROTOCOL_IP4,
+                                    &nh_10_10_10_2,
+                                    tm->hw[0]->sw_if_index,
+                                    ~0, // invalid fib index
+                                    1,
+                                    NULL,
+                                    FIB_ROUTE_PATH_FLAG_NONE);
+
+    /*
+     * Before adding a recursive via the BFD tracked ADJ-FIBs,
+     * bring one of the sessions UP, leave the other down
+     */
+    bfd_10_10_10_1.local_state = BFD_STATE_up;
+    fib_bfd_notify (BFD_LISTEN_EVENT_UPDATE, &bfd_10_10_10_1);
+    bfd_10_10_10_2.local_state = BFD_STATE_down;
+    fib_bfd_notify (BFD_LISTEN_EVENT_UPDATE, &bfd_10_10_10_2);
+
+    /*
+     * A recursive prefix via both of the ADJ FIBs
+     */
+    fib_prefix_t pfx_200_0_0_0_s_24 = {
+        .fp_proto = FIB_PROTOCOL_IP4,
+        .fp_len = 32,
+        .fp_addr = {
+            .ip4.as_u32 = clib_host_to_net_u32(0xc8000000),
+        },
+    };
+    const dpo_id_t *dpo_10_10_10_1, *dpo_10_10_10_2;
+
+    dpo_10_10_10_1 =
+        fib_entry_contribute_ip_forwarding(
+            fib_table_lookup_exact_match(0, &pfx_10_10_10_1_s_32));
+    dpo_10_10_10_2 =
+        fib_entry_contribute_ip_forwarding(
+            fib_table_lookup_exact_match(0, &pfx_10_10_10_2_s_32));
+
+    fib_test_lb_bucket_t lb_o_10_10_10_1 = {
+        .type = FT_LB_O_LB,
+        .lb = {
+            .lb = dpo_10_10_10_1->dpoi_index,
+        },
+    };
+    fib_test_lb_bucket_t lb_o_10_10_10_2 = {
+        .type = FT_LB_O_LB,
+        .lb = {
+            .lb = dpo_10_10_10_2->dpoi_index,
+        },
+    };
+
+    /*
+     * A prefix via the adj-fib that is BFD down => DROP
+     */
+    fei = fib_table_entry_path_add(0,
+                                   &pfx_200_0_0_0_s_24,
+                                   FIB_SOURCE_API,
+                                   FIB_ENTRY_FLAG_NONE,
+                                   FIB_PROTOCOL_IP4,
+                                   &nh_10_10_10_2,
+                                   ~0, // recursive
+                                   0, // default fib index
+                                   1,
+                                   NULL,
+                                   FIB_ROUTE_PATH_FLAG_NONE);
+    FIB_TEST(load_balance_is_drop(fib_entry_contribute_ip_forwarding(fei)),
+             "%U resolves via drop",
+             format_fib_prefix, &pfx_200_0_0_0_s_24);
+
+    /*
+     * add a path via the UP BFD adj-fib.
+     *  we expect that the DOWN BFD ADJ FIB is not used.
+     */
+    fei = fib_table_entry_path_add(0,
+                                   &pfx_200_0_0_0_s_24,
+                                   FIB_SOURCE_API,
+                                   FIB_ENTRY_FLAG_NONE,
+                                   FIB_PROTOCOL_IP4,
+                                   &nh_10_10_10_1,
+                                   ~0, // recursive
+                                   0, // default fib index
+                                   1,
+                                   NULL,
+                                   FIB_ROUTE_PATH_FLAG_NONE);
+
+    FIB_TEST(fib_test_validate_entry(fei,
+                                     FIB_FORW_CHAIN_TYPE_UNICAST_IP4,
+                                     1,
+                                     &lb_o_10_10_10_1),
+             "Recursive %U only UP BFD adj-fibs",
+             format_fib_prefix, &pfx_200_0_0_0_s_24);
+
+    /*
+     * Send a BFD state change to UP - both sessions are now up
+     *  the recursive prefix should LB over both
+     */
+    bfd_10_10_10_2.local_state = BFD_STATE_up;
+    fib_bfd_notify (BFD_LISTEN_EVENT_UPDATE, &bfd_10_10_10_2);
+
+
+    FIB_TEST(fib_test_validate_entry(fei,
+                                     FIB_FORW_CHAIN_TYPE_UNICAST_IP4,
+                                     2,
+                                     &lb_o_10_10_10_1,
+                                     &lb_o_10_10_10_2),
+             "Recursive %U via both UP BFD adj-fibs",
+             format_fib_prefix, &pfx_200_0_0_0_s_24);
+
+    /*
+     * Send a BFD state change to DOWN
+     *  the recursive prefix should exclude the down
+     */
+    bfd_10_10_10_2.local_state = BFD_STATE_down;
+    fib_bfd_notify (BFD_LISTEN_EVENT_UPDATE, &bfd_10_10_10_2);
+
+
+    FIB_TEST(fib_test_validate_entry(fei,
+                                     FIB_FORW_CHAIN_TYPE_UNICAST_IP4,
+                                     1,
+                                     &lb_o_10_10_10_1),
+             "Recursive %U via only UP",
+             format_fib_prefix, &pfx_200_0_0_0_s_24);
+
+    /*
+     * Delete the BFD session while it is in the DOWN state.
+     *  FIB should consider the entry's state as back up
+     */
+    fib_bfd_notify (BFD_LISTEN_EVENT_DELETE, &bfd_10_10_10_2);
+
+    FIB_TEST(fib_test_validate_entry(fei,
+                                     FIB_FORW_CHAIN_TYPE_UNICAST_IP4,
+                                     2,
+                                     &lb_o_10_10_10_1,
+                                     &lb_o_10_10_10_2),
+             "Recursive %U via both UP BFD adj-fibs post down session delete",
+             format_fib_prefix, &pfx_200_0_0_0_s_24);
+
+    /*
+     * Delete the BFD other session while it is in the UP state.
+     */
+    fib_bfd_notify (BFD_LISTEN_EVENT_DELETE, &bfd_10_10_10_1);
+
+    FIB_TEST(fib_test_validate_entry(fei,
+                                     FIB_FORW_CHAIN_TYPE_UNICAST_IP4,
+                                     2,
+                                     &lb_o_10_10_10_1,
+                                     &lb_o_10_10_10_2),
+             "Recursive %U via both UP BFD adj-fibs post up session delete",
+             format_fib_prefix, &pfx_200_0_0_0_s_24);
+
+    /*
+     * cleaup
+     */
+    fib_table_entry_delete(0, &pfx_200_0_0_0_s_24, FIB_SOURCE_API);
+    fib_table_entry_delete(0, &pfx_10_10_10_1_s_32, FIB_SOURCE_ADJ);
+    fib_table_entry_delete(0, &pfx_10_10_10_2_s_32, FIB_SOURCE_ADJ);
+
+    fib_table_entry_delete(0, &pfx_10_10_10_10_s_32, FIB_SOURCE_INTERFACE);
+    fib_table_entry_delete(0, &pfx_10_10_10_10_s_24, FIB_SOURCE_INTERFACE);
+
+    adj_unlock(ai_10_10_10_1);
+     /*
+     * test no-one left behind
+     */
+    FIB_TEST((n_feis == fib_entry_pool_size()), "Entries gone");
+    FIB_TEST(0 == adj_nbr_db_size(), "All adjacencies removed");
+
+    /*
+     * Single-hop BFD tests
+     */
+    bfd_10_10_10_1.hop_type = BFD_HOP_TYPE_SINGLE;
+    bfd_10_10_10_1.udp.key.sw_if_index = tm->hw[0]->sw_if_index;
+
+    adj_bfd_notify(BFD_LISTEN_EVENT_CREATE, &bfd_10_10_10_1);
+
+    ai_10_10_10_1 = adj_nbr_add_or_lock(FIB_PROTOCOL_IP4,
+                                        VNET_LINK_IP4,
+                                        &nh_10_10_10_1,
+                                        tm->hw[0]->sw_if_index);
+    /*
+     * whilst the BFD session is not signalled, the adj is up
+     */
+    FIB_TEST(adj_is_up(ai_10_10_10_1), "Adj state up on uninit session");
+
+    /*
+     * bring the BFD session up
+     */
+    bfd_10_10_10_1.local_state = BFD_STATE_up;
+    adj_bfd_notify(BFD_LISTEN_EVENT_UPDATE, &bfd_10_10_10_1);
+    FIB_TEST(adj_is_up(ai_10_10_10_1), "Adj state up on UP session");
+
+    /*
+     * bring the BFD session down
+     */
+    bfd_10_10_10_1.local_state = BFD_STATE_down;
+    adj_bfd_notify(BFD_LISTEN_EVENT_UPDATE, &bfd_10_10_10_1);
+    FIB_TEST(!adj_is_up(ai_10_10_10_1), "Adj state down on DOWN session");
+
+
+    /*
+     * add an attached next hop FIB entry via the down adj
+     */
+    fib_prefix_t pfx_5_5_5_5_s_32 = {
+        .fp_addr = {
+            .ip4 = {
+                .as_u32 = clib_host_to_net_u32(0x05050505),
+            },
+        },
+        .fp_len = 32,
+        .fp_proto = FIB_PROTOCOL_IP4,
+    };
+
+    fei = fib_table_entry_path_add(0,
+                                   &pfx_5_5_5_5_s_32,
+                                   FIB_SOURCE_CLI,
+                                   FIB_ENTRY_FLAG_NONE,
+                                   FIB_PROTOCOL_IP4,
+                                   &nh_10_10_10_1,
+                                   tm->hw[0]->sw_if_index,
+                                   ~0, // invalid fib index
+                                   1,
+                                   NULL,
+                                   FIB_ROUTE_PATH_FLAG_NONE);
+    FIB_TEST(load_balance_is_drop(fib_entry_contribute_ip_forwarding(fei)),
+             "%U resolves via drop",
+             format_fib_prefix, &pfx_5_5_5_5_s_32);
+
+    /*
+     * Add a path via an ADJ that is up
+     */
+    adj_index_t ai_10_10_10_2 = adj_nbr_add_or_lock(FIB_PROTOCOL_IP4,
+                                                    VNET_LINK_IP4,
+                                                    &nh_10_10_10_2,
+                                                    tm->hw[0]->sw_if_index);
+
+    fib_test_lb_bucket_t adj_o_10_10_10_2 = {
+        .type = FT_LB_ADJ,
+        .adj = {
+            .adj = ai_10_10_10_2,
+        },
+    };
+    adj_o_10_10_10_1.adj.adj = ai_10_10_10_1;
+
+    fei = fib_table_entry_path_add(0,
+                                   &pfx_5_5_5_5_s_32,
+                                   FIB_SOURCE_CLI,
+                                   FIB_ENTRY_FLAG_NONE,
+                                   FIB_PROTOCOL_IP4,
+                                   &nh_10_10_10_2,
+                                   tm->hw[0]->sw_if_index,
+                                   ~0, // invalid fib index
+                                   1,
+                                   NULL,
+                                   FIB_ROUTE_PATH_FLAG_NONE);
+
+    FIB_TEST(fib_test_validate_entry(fei,
+                                     FIB_FORW_CHAIN_TYPE_UNICAST_IP4,
+                                     1,
+                                     &adj_o_10_10_10_2),
+             "BFD sourced %U via %U",
+             format_fib_prefix, &pfx_5_5_5_5_s_32,
+             format_ip_adjacency, ai_10_10_10_2, FORMAT_IP_ADJACENCY_NONE);
+
+    /*
+     * Bring up the down session - should now LB
+     */
+    bfd_10_10_10_1.local_state = BFD_STATE_up;
+    adj_bfd_notify(BFD_LISTEN_EVENT_UPDATE, &bfd_10_10_10_1);
+    FIB_TEST(fib_test_validate_entry(fei,
+                                     FIB_FORW_CHAIN_TYPE_UNICAST_IP4,
+                                     2,
+                                     &adj_o_10_10_10_1,
+                                     &adj_o_10_10_10_2),
+             "BFD sourced %U via noth adjs",
+             format_fib_prefix, &pfx_5_5_5_5_s_32);
+
+    /*
+     * remove the BFD session state from the adj
+     */
+    adj_bfd_notify(BFD_LISTEN_EVENT_DELETE, &bfd_10_10_10_1);
+
+    /*
+     * clean-up
+     */
+    fib_table_entry_delete(0, &pfx_5_5_5_5_s_32, FIB_SOURCE_CLI);
+    adj_unlock(ai_10_10_10_1);
+    adj_unlock(ai_10_10_10_2);
+
+    /*
+     * test no-one left behind
+     */
+    FIB_TEST((n_feis == fib_entry_pool_size()), "Entries gone");
+    FIB_TEST(0 == adj_nbr_db_size(), "All adjacencies removed");
+    return (0);
+}
+
 static int
 lfib_test (void)
 {
@@ -7119,6 +7631,11 @@ fib_test (vlib_main_t * vm,
     res = 0;
     fib_test_mk_intf(4);
 
+    if (unformat (input, "debug"))
+    {
+        fib_test_do_debug = 1;
+    }
+
     if (unformat (input, "ip"))
     {
 	res += fib_test_v4();
@@ -7140,6 +7657,10 @@ fib_test (vlib_main_t * vm,
     {
 	res += fib_test_walk();
     }
+    else if (unformat (input, "bfd"))
+    {
+	res += fib_test_bfd();
+    }
     else
     {
         /*
@@ -7151,6 +7672,7 @@ fib_test (vlib_main_t * vm,
 	res += fib_test_v4();
 	res += fib_test_v6();
 	res += fib_test_ae();
+	res += fib_test_bfd();
 	res += fib_test_label();
 	res += lfib_test();
     }