IP Multicast FIB (mfib)

 - IPv[46] mfib tables with support for (*,G/m), (*,G) and (S,G) exact and longest prefix match
 - Replication represented via a new replicate DPO.
 - RPF configuration and data-plane checking
 - data-plane signals sent to listening control planes.

The functions of multicast forwarding entries differ from their unicast conterparts, so we introduce a new mfib_table_t and mfib_entry_t objects. However, we re-use the fib_path_list to resolve and build the entry's output list. the fib_path_list provides the service to construct a replicate DPO for multicast.

'make tests' is added to with two new suites; TEST=mfib, this is invocation of the CLI command 'test mfib' which deals with many path add/remove, flag set/unset scenarios, TEST=ip-mcast, data-plane forwarding tests.

Updated applications to use the new MIFB functions;
  - IPv6 NS/RA.
  - DHCPv6
 unit tests for these are undated accordingly.

Change-Id: I49ec37b01f1b170335a5697541c8fd30e6d3a961
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 201 insertions, 0 deletions

diff --git a/src/vnet/mfib/mfib_signal.c b/src/vnet/mfib/mfib_signal.c
new file mode 100644
index 00000000000..9f6205de419
--- /dev/null
+++ b/src/vnet/mfib/mfib_signal.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include <vnet/vnet.h>
+#include <vnet/mfib/mfib_signal.h>
+#include <vppinfra/dlist.h>
+
+/**
+ * @brief Pool of signals
+ */
+static mfib_signal_t *mfib_signal_pool;
+
+/**
+ * @brief pool of dlist elements
+ */
+static dlist_elt_t *mfib_signal_dlist_pool;
+
+/**
+ * the list/set of interfaces with signals pending
+ */
+typedef struct mfib_signal_q_t_
+{
+    /**
+     * the dlist indext that is the head of the list
+     */
+    u32 mip_head;
+
+    /**
+     * Spin lock to protect the list
+     */
+    int mip_lock;
+} mfib_signal_q_t;
+
+/**
+ * @brief The pending queue of signals to deliver to the control plane
+ */
+static mfib_signal_q_t mfib_signal_pending ;
+
+static void
+mfib_signal_list_init (void)
+{
+    dlist_elt_t *head;
+    u32 hi;
+
+    pool_get(mfib_signal_dlist_pool, head);
+    hi = head - mfib_signal_dlist_pool;
+
+    mfib_signal_pending.mip_head = hi;
+    clib_dlist_init(mfib_signal_dlist_pool, hi);
+}
+
+void
+mfib_signal_module_init (void)
+{
+    mfib_signal_list_init();
+}
+
+int
+mfib_signal_send_one (struct _unix_shared_memory_queue *q,
+                      u32 context)
+{
+    u32 li, si;
+
+    /*
+     * with the lock held, pop a signal from the q.
+     */
+    while (__sync_lock_test_and_set (&mfib_signal_pending.mip_lock, 1))
+        ;
+    {
+        li = clib_dlist_remove_head(mfib_signal_dlist_pool,
+                                    mfib_signal_pending.mip_head);
+    }
+    mfib_signal_pending.mip_lock = 0;
+
+    if (~0 != li)
+    {
+        mfib_signal_t *mfs;
+        mfib_itf_t *mfi;
+        dlist_elt_t *elt;
+
+        elt = pool_elt_at_index(mfib_signal_dlist_pool, li);
+        si = elt->value;
+
+        mfs = pool_elt_at_index(mfib_signal_pool, si);
+        mfi = mfib_itf_get(mfs->mfs_itf);
+        mfi->mfi_si = INDEX_INVALID;
+        __sync_fetch_and_and(&mfi->mfi_flags,
+                             ~MFIB_ITF_FLAG_SIGNAL_PRESENT);
+
+
+        vl_mfib_signal_send_one(q, context, mfs);
+
+        /*
+         * with the lock held, return the resoruces of the signals posted
+         */
+        while (__sync_lock_test_and_set(&mfib_signal_pending.mip_lock, 1))
+            ;
+        {
+            pool_put_index(mfib_signal_pool, si);
+            pool_put_index(mfib_signal_dlist_pool, li);
+        }
+        mfib_signal_pending.mip_lock = 0;
+
+        return (1);
+    }
+    return (0);
+}
+
+void
+mfib_signal_push (const mfib_entry_t *mfe,
+                  mfib_itf_t *mfi,
+                  vlib_buffer_t *b0)
+{
+    mfib_signal_t *mfs;
+    dlist_elt_t *elt;
+    u32 si, li;
+
+    while (__sync_lock_test_and_set (&mfib_signal_pending.mip_lock, 1))
+        ;
+    {
+        pool_get(mfib_signal_pool, mfs);
+        pool_get(mfib_signal_dlist_pool, elt);
+
+        si = mfs - mfib_signal_pool;
+        li = elt - mfib_signal_dlist_pool;
+
+        elt->value = si;
+        mfi->mfi_si = li;
+
+        clib_dlist_addhead(mfib_signal_dlist_pool,
+                           mfib_signal_pending.mip_head,
+                           li);
+    }
+    mfib_signal_pending.mip_lock = 0;
+
+    mfs->mfs_entry = mfib_entry_get_index(mfe);
+    mfs->mfs_itf = mfib_itf_get_index(mfi);
+
+    if (NULL != b0)
+    {
+        mfs->mfs_buffer_len = b0->current_length;
+        memcpy(mfs->mfs_buffer,
+               vlib_buffer_get_current(b0),
+               (mfs->mfs_buffer_len > MFIB_SIGNAL_BUFFER_SIZE ?
+                MFIB_SIGNAL_BUFFER_SIZE :
+                mfs->mfs_buffer_len));
+    }
+    else
+    {
+        mfs->mfs_buffer_len = 0;
+    }
+}
+
+void
+mfib_signal_remove_itf (const mfib_itf_t *mfi)
+{
+    u32 li;
+
+    /*
+     * lock the queue to prevent further additions while we fiddle.
+     */
+    li = mfi->mfi_si;
+
+    if (INDEX_INVALID != li)
+    {
+        /*
+         * it's in the pending q
+         */
+        while (__sync_lock_test_and_set (&mfib_signal_pending.mip_lock, 1))
+            ;
+        {
+            dlist_elt_t *elt;
+
+            /*
+             * with the lock held;
+             *  - remove the signal from the pending list
+             *  - free up the signal and list entry obejcts
+             */
+            clib_dlist_remove(mfib_signal_dlist_pool, li);
+
+            elt = pool_elt_at_index(mfib_signal_dlist_pool, li);
+            pool_put_index(mfib_signal_pool, elt->value);
+            pool_put(mfib_signal_dlist_pool, elt);
+        }
+
+        mfib_signal_pending.mip_lock = 0;
+    }
+}