VPP-69: Create fib or bridge domain with arbitrary ID

It appeared to me that it might be usefull
to allow users to create fibs or bridge domains without
a complete knowledge of the current used IDs.

These changes define fib and bridge domain constructors
when the provided ID is ~0. In such a case, an unused ID is
used to create a new fib or bridge domain.

Change-Id: Iaba69a023296e6d17bdde45980f9db84832a3995
Signed-off-by: Pierre Pfister <ppfister@cisco.com>

6 files changed, 89 insertions, 3 deletions

diff --git a/vnet/vnet/ip/ip4.h b/vnet/vnet/ip/ip4.h
index 5c530b74952..b14541eb2ef 100644
--- a/vnet/vnet/ip/ip4.h
+++ b/vnet/vnet/ip/ip4.h
@@ -293,6 +293,28 @@ typedef struct {
   u32 n_add_adj;
 } ip4_add_del_route_args_t;
 
+/**
+ * \brief Get or create an IPv4 fib.
+ *
+ * Get or create an IPv4 fib with the provided fib ID or index.
+ * The fib ID is a possibly-sparse user-defined value while
+ * the fib index defines the position of the fib in the fib vector.
+ *
+ * \param im
+ *      ip4_main pointer.
+ * \param table_index_or_id
+ *      The table index if \c IP4_ROUTE_FLAG_FIB_INDEX bit is set in \p flags.
+ *      Otherwise, when set to \c ~0, an arbitrary and unused fib ID is picked
+ *      and can be retrieved with \c ret->table_id.
+ *      Otherwise, the fib ID to be used to retrieve or create the desired fib.
+ * \param flags
+ *      Indicates whether \p table_index_or_id is the fib index or ID.
+ *      When the bit \c IP4_ROUTE_FLAG_FIB_INDEX is set, \p table_index_or_id
+ *      is considered as the fib index, and the fib ID otherwise.
+ * \returns A pointer to the retrieved or created fib.
+ *
+ * \remark When getting a fib with the fib index, the fib MUST already exist.
+ */
 ip4_fib_t *
 find_ip4_fib_by_table_index_or_id (ip4_main_t * im, 
                                    u32 table_index_or_id, u32 flags);
diff --git a/vnet/vnet/ip/ip4_forward.c b/vnet/vnet/ip/ip4_forward.c
index a50664cc662..a84b83bc225 100644
--- a/vnet/vnet/ip/ip4_forward.c
+++ b/vnet/vnet/ip/ip4_forward.c
@@ -103,6 +103,14 @@ find_ip4_fib_by_table_index_or_id (ip4_main_t * im,
   fib_index = table_index_or_id;
   if (! (flags & IP4_ROUTE_FLAG_FIB_INDEX))
     {
+      if (table_index_or_id == ~0) {
+        table_index_or_id = 0;
+        while ((p = hash_get (im->fib_index_by_table_id, table_index_or_id))) {
+          table_index_or_id++;
+        }
+        return create_fib_with_table_id (im, table_index_or_id);
+      }
+
       p = hash_get (im->fib_index_by_table_id, table_index_or_id);
       if (! p)
 	return create_fib_with_table_id (im, table_index_or_id);
diff --git a/vnet/vnet/ip/ip6.h b/vnet/vnet/ip/ip6.h
index b1043595c29..4d0e8564aa2 100644
--- a/vnet/vnet/ip/ip6.h
+++ b/vnet/vnet/ip/ip6.h
@@ -204,6 +204,29 @@ typedef union {
 u32 ip6_fib_lookup (ip6_main_t * im, u32 sw_if_index, ip6_address_t * dst);
 u32 ip6_fib_lookup_with_table (ip6_main_t * im, u32 fib_index, 
                                ip6_address_t * dst);
+
+/**
+ * \brief Get or create an IPv6 fib.
+ *
+ * Get or create an IPv6 fib with the provided fib ID or index.
+ * The fib ID is a possibly-sparse user-defined value while
+ * the fib index defines the position of the fib in the fib vector.
+ *
+ * \param im
+ *      ip6_main pointer.
+ * \param table_index_or_id
+ *      The table index if \c IP6_ROUTE_FLAG_FIB_INDEX bit is set in \p flags.
+ *      Otherwise, when set to \c ~0, an arbitrary and unused fib ID is picked
+ *      and can be retrieved with \c ret->table_id.
+ *      Otherwise, it is the fib ID to be used to retrieve or create the desired fib.
+ * \param flags
+ *      Indicates whether \p table_index_or_id is the fib index or ID.
+ *      When the bit \c IP6_ROUTE_FLAG_FIB_INDEX is set, \p table_index_or_id
+ *      is considered as the fib index, and the fib ID otherwise.
+ * \return A pointer to the retrieved or created fib.
+ *
+ * \remark When getting a fib with the fib index, the fib MUST already exist.
+ */
 ip6_fib_t * find_ip6_fib_by_table_index_or_id (ip6_main_t * im, 
                                                u32 table_index_or_id, 
                                                u32 flags);
diff --git a/vnet/vnet/ip/ip6_forward.c b/vnet/vnet/ip/ip6_forward.c
index e82e0a6b472..a136da3e142 100644
--- a/vnet/vnet/ip/ip6_forward.c
+++ b/vnet/vnet/ip/ip6_forward.c
@@ -189,6 +189,14 @@ find_ip6_fib_by_table_index_or_id (ip6_main_t * im, u32 table_index_or_id, u32 f
   fib_index = table_index_or_id;
   if (! (flags & IP6_ROUTE_FLAG_FIB_INDEX))
     {
+      if (table_index_or_id == ~0) {
+        table_index_or_id = 0;
+        while (hash_get (im->fib_index_by_table_id, table_index_or_id)) {
+          table_index_or_id++;
+        }
+        return create_fib_with_table_id (im, table_index_or_id);
+      }
+
       p = hash_get (im->fib_index_by_table_id, table_index_or_id);
       if (! p)
 	return create_fib_with_table_id (im, table_index_or_id);
diff --git a/vnet/vnet/l2/l2_bd.c b/vnet/vnet/l2/l2_bd.c
index 31f02c63eff..0676a2869a2 100644
--- a/vnet/vnet/l2/l2_bd.c
+++ b/vnet/vnet/l2/l2_bd.c
@@ -54,9 +54,15 @@ u32 bd_find_or_add_bd_index (bd_main_t * bdm, u32 bd_id)
   uword * p;
   u32 rv;
 
-  p = hash_get (bdm->bd_index_by_bd_id, bd_id);
-  if (p)
-    return (p[0]);
+  if (bd_id == ~0) {
+    bd_id = 0;
+    while (hash_get (bdm->bd_index_by_bd_id, bd_id))
+      bd_id++;
+  } else {
+    p = hash_get (bdm->bd_index_by_bd_id, bd_id);
+    if (p)
+      return (p[0]);
+  }
   
   rv = clib_bitmap_first_clear (bdm->bd_index_bitmap);
 
diff --git a/vnet/vnet/l2/l2_bd.h b/vnet/vnet/l2/l2_bd.h
index 034f2b39875..d84c8e802d5 100644
--- a/vnet/vnet/l2/l2_bd.h
+++ b/vnet/vnet/l2/l2_bd.h
@@ -104,7 +104,26 @@ bd_set_flags (vlib_main_t * vm,
               u32 flags,
               u32 enable);
 
+/**
+ * \brief Get or create a bridge domain.
+ *
+ * Get or create a bridge domain with the given bridge domain ID.
+ *
+ * \param bdm bd_main pointer.
+ * \param bd_id The bridge domain ID or ~0 if an arbitrary unused bridge domain should be used.
+ * \return The bridge domain index in \c l2input_main->l2_bridge_domain_t vector.
+ */
 u32 bd_find_or_add_bd_index (bd_main_t * bdm, u32 bd_id);
+
+/**
+ * \brief Delete a bridge domain.
+ *
+ * Delete an existing bridge domain with the given bridge domain ID.
+ *
+ * \param bdm bd_main pointer.
+ * \param bd_id The bridge domain ID.
+ * \return 0 on success and -1 if the bridge domain does not exist.
+ */
 int bd_delete_bd_index (bd_main_t * bdm, u32 bd_id);
 
 u32 bd_add_del_ip_mac(u32 bd_index,