Sub-net broadcast addresses for IPv4

Change-Id: Ib2189d01e8bc61de57404159690fb70f89c47277
Signed-off-by: Neale Ranns <nranns@cisco.com>

3 files changed, 92 insertions, 4 deletions

diff --git a/src/vnet/classify/vnet_classify.c b/src/vnet/classify/vnet_classify.c
index b651a1f1eb3..98842a481b8 100644
--- a/src/vnet/classify/vnet_classify.c
+++ b/src/vnet/classify/vnet_classify.c
@@ -1499,7 +1499,7 @@ static u8 * format_vnet_classify_table (u8 * s, va_list * args)
   s = format (s, "%10u%10d%10d%10d", index, t->active_elements,
               t->next_table_index, t->miss_next_index);
 
-  s = format (s, "\n  Heap: %U", format_mheap, t->mheap, 0 /*verbose*/); 
+  s = format (s, "\n  Heap: %U", format_mheap, t->mheap, 0 /*verbose*/);
 
   s = format (s, "\n  nbuckets %d, skip %d match %d flag %d offset %d",
               t->nbuckets, t->skip_n_vectors, t->match_n_vectors,
diff --git a/src/vnet/fib/fib_entry_src_interface.c b/src/vnet/fib/fib_entry_src_interface.c
index ca04716ed8f..bb87818fe4b 100644
--- a/src/vnet/fib/fib_entry_src_interface.c
+++ b/src/vnet/fib/fib_entry_src_interface.c
@@ -32,6 +32,25 @@ fib_entry_src_interface_init (fib_entry_src_t *src)
 }
 
 static void
+fib_entry_src_interface_add (fib_entry_src_t *src,
+                             const fib_entry_t *entry,
+                             fib_entry_flag_t flags,
+                             fib_protocol_t proto,
+                             const dpo_id_t *dpo)
+{
+    src->fes_pl = fib_path_list_create_special(
+                      proto,
+                      fib_entry_src_flags_2_path_list_flags(flags),
+                      dpo);
+}
+
+static void
+fib_entry_src_interface_remove (fib_entry_src_t *src)
+{
+    src->fes_pl = FIB_NODE_INDEX_INVALID;
+}
+
+static void
 fib_entry_src_interface_path_swap (fib_entry_src_t *src,
 				   const fib_entry_t *entry,
 				   fib_path_list_flags_t pl_flags,
@@ -176,6 +195,8 @@ fib_entry_src_interface_format (fib_entry_src_t *src,
 
 const static fib_entry_src_vft_t interface_src_vft = {
     .fesv_init = fib_entry_src_interface_init,
+    .fesv_add = fib_entry_src_interface_add,
+    .fesv_remove = fib_entry_src_interface_remove,
     .fesv_path_swap = fib_entry_src_interface_path_swap,
     .fesv_activate = fib_entry_src_interface_activate,
     .fesv_deactivate = fib_entry_src_interface_deactivate,
diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
index f2bc2a71851..bbba4b70e01 100644
--- a/src/vnet/ip/ip4_forward.c
+++ b/src/vnet/ip/ip4_forward.c
@@ -745,8 +745,9 @@ ip4_add_interface_routes (u32 sw_if_index,
 
   a->neighbor_probe_adj_index = ~0;
 
-  if (pfx.fp_len < 32)
+  if (pfx.fp_len <= 30)
     {
+      /* a /30 or shorter - add a glean for the network address */
       fib_node_index_t fei;
 
       fei = fib_table_entry_update_one_path (fib_index, &pfx,
@@ -764,8 +765,50 @@ ip4_add_interface_routes (u32 sw_if_index,
                                              NULL,
 					     FIB_ROUTE_PATH_FLAG_NONE);
       a->neighbor_probe_adj_index = fib_entry_get_adj (fei);
-    }
 
+      /* Add the two broadcast addresses as drop */
+      fib_prefix_t net_pfx = {
+        .fp_len = 32,
+        .fp_proto = FIB_PROTOCOL_IP4,
+        .fp_addr.ip4.as_u32 = address->as_u32 & im->fib_masks[pfx.fp_len],
+      };
+      if (net_pfx.fp_addr.ip4.as_u32 != pfx.fp_addr.ip4.as_u32)
+        fib_table_entry_special_add(fib_index,
+                                    &net_pfx,
+                                    FIB_SOURCE_INTERFACE,
+                                    (FIB_ENTRY_FLAG_DROP |
+                                     FIB_ENTRY_FLAG_LOOSE_URPF_EXEMPT),
+                                    ADJ_INDEX_INVALID);
+      net_pfx.fp_addr.ip4.as_u32 |= ~im->fib_masks[pfx.fp_len];
+      if (net_pfx.fp_addr.ip4.as_u32 != pfx.fp_addr.ip4.as_u32)
+        fib_table_entry_special_add(fib_index,
+                                    &net_pfx,
+                                    FIB_SOURCE_INTERFACE,
+                                    (FIB_ENTRY_FLAG_DROP |
+                                     FIB_ENTRY_FLAG_LOOSE_URPF_EXEMPT),
+                                    ADJ_INDEX_INVALID);
+    }
+  else if (pfx.fp_len == 31)
+    {
+      u32 mask = clib_host_to_net_u32(1);
+      fib_prefix_t net_pfx = pfx;
+
+      net_pfx.fp_len = 32;
+      net_pfx.fp_addr.ip4.as_u32 ^= mask;
+
+      /* a /31 - add the other end as an attached host */
+      fib_table_entry_update_one_path (fib_index, &net_pfx,
+                                       FIB_SOURCE_INTERFACE,
+                                       (FIB_ENTRY_FLAG_ATTACHED),
+                                       FIB_PROTOCOL_IP4,
+                                       &net_pfx.fp_addr,
+                                       sw_if_index,
+                                       // invalid FIB index
+                                       ~0,
+                                       1,
+                                       NULL,
+                                       FIB_ROUTE_PATH_FLAG_NONE);
+    }
   pfx.fp_len = 32;
 
   if (sw_if_index < vec_len (lm->classify_table_index_by_sw_if_index))
@@ -813,10 +856,34 @@ ip4_del_interface_routes (ip4_main_t * im,
     .fp_addr.ip4 = *address,
   };
 
-  if (pfx.fp_len < 32)
+  if (pfx.fp_len <= 30)
     {
+      fib_prefix_t net_pfx = {
+        .fp_len = 32,
+        .fp_proto = FIB_PROTOCOL_IP4,
+        .fp_addr.ip4.as_u32 = address->as_u32 & im->fib_masks[pfx.fp_len],
+      };
+      if (net_pfx.fp_addr.ip4.as_u32 != pfx.fp_addr.ip4.as_u32)
+        fib_table_entry_special_remove(fib_index,
+                                       &net_pfx,
+                                       FIB_SOURCE_INTERFACE);
+      net_pfx.fp_addr.ip4.as_u32 |= ~im->fib_masks[pfx.fp_len];
+      if (net_pfx.fp_addr.ip4.as_u32 != pfx.fp_addr.ip4.as_u32)
+        fib_table_entry_special_remove(fib_index,
+                                       &net_pfx,
+                                       FIB_SOURCE_INTERFACE);
       fib_table_entry_delete (fib_index, &pfx, FIB_SOURCE_INTERFACE);
     }
+    else if (pfx.fp_len == 31)
+    {
+      u32 mask = clib_host_to_net_u32(1);
+      fib_prefix_t net_pfx = pfx;
+
+      net_pfx.fp_len = 32;
+      net_pfx.fp_addr.ip4.as_u32 ^= mask;
+
+      fib_table_entry_delete (fib_index, &net_pfx, FIB_SOURCE_INTERFACE);
+    }
 
   pfx.fp_len = 32;
   fib_table_entry_delete (fib_index, &pfx, FIB_SOURCE_INTERFACE);