Distributed Virtual Router Support

A distributed virtual router works by attmpeting to switch a packet, but on failing to find a local consumer (i.e. the packet is destined to a locally attached host) then the packet is sent unmodified 'upstream' to where the rest of the 'distributed' router is present. When L3 switching a packet this means the L2 header must not be modifed. This patch adds a 'l2-bridge' object to the L3 FIB which re-injects packets from the L3 path back into the L2 path - use with extreme caution.

Change-Id: I069724eb45956647d7980cbe40a80a788ee6ee82
Signed-off-by: Neale Ranns <nranns@cisco.com>

4 files changed, 436 insertions, 1 deletions

diff --git a/src/vnet/dpo/dpo.c b/src/vnet/dpo/dpo.c
index bd18b66bfd5..e94f347466e 100644
--- a/src/vnet/dpo/dpo.c
+++ b/src/vnet/dpo/dpo.c
@@ -40,6 +40,7 @@
 #include <vnet/dpo/interface_rx_dpo.h>
 #include <vnet/dpo/interface_tx_dpo.h>
 #include <vnet/dpo/mpls_disposition.h>
+#include <vnet/dpo/l2_bridge_dpo.h>
 
 /**
  * Array of char* names for the DPO types and protos
@@ -523,6 +524,7 @@ dpo_module_init (vlib_main_t * vm)
     interface_rx_dpo_module_init();
     interface_tx_dpo_module_init();
     mpls_disp_dpo_module_init();
+    l2_bridge_dpo_module_init();
 
     return (NULL);
 }
diff --git a/src/vnet/dpo/dpo.h b/src/vnet/dpo/dpo.h
index 33562968272..d1309c19031 100644
--- a/src/vnet/dpo/dpo.h
+++ b/src/vnet/dpo/dpo.h
@@ -114,6 +114,7 @@ typedef enum dpo_type_t_ {
     DPO_MFIB_ENTRY,
     DPO_INTERFACE_RX,
     DPO_INTERFACE_TX,
+    DPO_L2_BRIDGE,
     DPO_LAST,
 } __attribute__((packed)) dpo_type_t;
 
@@ -140,7 +141,8 @@ typedef enum dpo_type_t_ {
     [DPO_MPLS_DISPOSITION] = "dpo-mpls-diposition", \
     [DPO_MFIB_ENTRY] = "dpo-mfib_entry", \
     [DPO_INTERFACE_RX] = "dpo-interface-rx",	\
-    [DPO_INTERFACE_TX] = "dpo-interface-tx"	\
+    [DPO_INTERFACE_TX] = "dpo-interface-tx",	\
+    [DPO_L2_BRIDGE] = "dpo-l2-bridge"	\
 }
 
 /**
diff --git a/src/vnet/dpo/l2_bridge_dpo.c b/src/vnet/dpo/l2_bridge_dpo.c
new file mode 100644
index 00000000000..169478148c3
--- /dev/null
+++ b/src/vnet/dpo/l2_bridge_dpo.c
@@ -0,0 +1,375 @@
+/*
+ * 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/dpo/l2_bridge_dpo.h>
+#include <vnet/fib/fib_node.h>
+#include <vnet/ethernet/ethernet.h>
+
+/*
+ * The 'DB' of L2 bridge DPOs.
+ * There is only one per-interface, so this is a per-interface vector
+ */
+static index_t *l2_bridge_dpo_db;
+
+static l2_bridge_dpo_t *
+l2_bridge_dpo_alloc (void)
+{
+    l2_bridge_dpo_t *l2b;
+
+    pool_get(l2_bridge_dpo_pool, l2b);
+
+    return (l2b);
+}
+
+static inline l2_bridge_dpo_t *
+l2_bridge_dpo_get_from_dpo (const dpo_id_t *dpo)
+{
+    ASSERT(DPO_L2_BRIDGE == dpo->dpoi_type);
+
+    return (l2_bridge_dpo_get(dpo->dpoi_index));
+}
+
+static inline index_t
+l2_bridge_dpo_get_index (l2_bridge_dpo_t *l2b)
+{
+    return (l2b - l2_bridge_dpo_pool);
+}
+
+static void
+l2_bridge_dpo_lock (dpo_id_t *dpo)
+{
+    l2_bridge_dpo_t *l2b;
+
+    l2b = l2_bridge_dpo_get_from_dpo(dpo);
+    l2b->l2b_locks++;
+}
+
+static void
+l2_bridge_dpo_unlock (dpo_id_t *dpo)
+{
+    l2_bridge_dpo_t *l2b;
+
+    l2b = l2_bridge_dpo_get_from_dpo(dpo);
+    l2b->l2b_locks--;
+
+    if (0 == l2b->l2b_locks)
+    {
+        l2_bridge_dpo_db[l2b->l2b_sw_if_index] = INDEX_INVALID;
+        pool_put(l2_bridge_dpo_pool, l2b);
+    }
+}
+
+/*
+ * l2_bridge_dpo_add_or_lock
+ *
+ * Add/create and lock a new or lock an existing for the L2 Bridge
+ * on the interface given
+ */
+void
+l2_bridge_dpo_add_or_lock (u32 sw_if_index,
+                           dpo_id_t *dpo)
+{
+    l2_bridge_dpo_t *l2b;
+
+    vec_validate_init_empty(l2_bridge_dpo_db,
+                            sw_if_index,
+                            INDEX_INVALID);
+
+    if (INDEX_INVALID == l2_bridge_dpo_db[sw_if_index])
+    {
+        l2b = l2_bridge_dpo_alloc();
+
+        l2b->l2b_sw_if_index = sw_if_index;
+
+        l2_bridge_dpo_db[sw_if_index] =
+            l2_bridge_dpo_get_index(l2b);
+    }
+    else
+    {
+        l2b = l2_bridge_dpo_get(l2_bridge_dpo_db[sw_if_index]);
+    }
+
+    dpo_set(dpo, DPO_L2_BRIDGE, DPO_PROTO_ETHERNET, l2_bridge_dpo_get_index(l2b));
+}
+
+
+static clib_error_t *
+l2_bridge_dpo_interface_state_change (vnet_main_t * vnm,
+                                      u32 sw_if_index,
+                                      u32 flags)
+{
+    /*
+     */
+    return (NULL);
+}
+
+VNET_SW_INTERFACE_ADMIN_UP_DOWN_FUNCTION(
+    l2_bridge_dpo_interface_state_change);
+
+/**
+ * @brief Registered callback for HW interface state changes
+ */
+static clib_error_t *
+l2_bridge_dpo_hw_interface_state_change (vnet_main_t * vnm,
+                                         u32 hw_if_index,
+                                         u32 flags)
+{
+    return (NULL);
+}
+
+VNET_HW_INTERFACE_LINK_UP_DOWN_FUNCTION(
+    l2_bridge_dpo_hw_interface_state_change);
+
+static clib_error_t *
+l2_bridge_dpo_interface_delete (vnet_main_t * vnm,
+                                u32 sw_if_index,
+                                u32 is_add)
+{
+    return (NULL);
+}
+
+VNET_SW_INTERFACE_ADD_DEL_FUNCTION(
+    l2_bridge_dpo_interface_delete);
+
+u8*
+format_l2_bridge_dpo (u8* s, va_list *ap)
+{
+    index_t index = va_arg(*ap, index_t);
+    CLIB_UNUSED(u32 indent) = va_arg(*ap, u32);
+    vnet_main_t * vnm = vnet_get_main();
+    l2_bridge_dpo_t *l2b = l2_bridge_dpo_get(index);
+
+    return (format(s, "l2-bridge-%U-dpo",
+                   format_vnet_sw_interface_name,
+                   vnm,
+                   vnet_get_sw_interface(vnm, l2b->l2b_sw_if_index)));
+}
+
+static void
+l2_bridge_dpo_mem_show (void)
+{
+    fib_show_memory_usage("L2-bridge",
+                          pool_elts(l2_bridge_dpo_pool),
+                          pool_len(l2_bridge_dpo_pool),
+                          sizeof(l2_bridge_dpo_t));
+}
+
+
+const static dpo_vft_t l2_bridge_dpo_vft = {
+    .dv_lock = l2_bridge_dpo_lock,
+    .dv_unlock = l2_bridge_dpo_unlock,
+    .dv_format = format_l2_bridge_dpo,
+    .dv_mem_show = l2_bridge_dpo_mem_show,
+};
+
+/**
+ * @brief The per-protocol VLIB graph nodes that are assigned to a glean
+ *        object.
+ *
+ * this means that these graph nodes are ones from which a glean is the
+ * parent object in the DPO-graph.
+ */
+const static char* const l2_bridge_dpo_l2_nodes[] =
+{
+    "l2-bridge-dpo",
+    NULL,
+};
+
+const static char* const * const l2_bridge_dpo_nodes[DPO_PROTO_NUM] =
+{
+    [DPO_PROTO_ETHERNET]  = l2_bridge_dpo_l2_nodes,
+};
+
+void
+l2_bridge_dpo_module_init (void)
+{
+    dpo_register(DPO_L2_BRIDGE,
+                 &l2_bridge_dpo_vft,
+                 l2_bridge_dpo_nodes);
+}
+
+/**
+ * @brief Interface DPO trace data
+ */
+typedef struct l2_bridge_dpo_trace_t_
+{
+    u32 sw_if_index;
+} l2_bridge_dpo_trace_t;
+
+typedef enum l2_bridge_dpo_next_t_
+{
+    L2_BRIDGE_DPO_DROP = 0,
+    L2_BRIDGE_DPO_OUTPUT = 1,
+} l2_bridge_dpo_next_t;
+
+always_inline uword
+l2_bridge_dpo_inline (vlib_main_t * vm,
+                      vlib_node_runtime_t * node,
+                      vlib_frame_t * from_frame)
+{
+    u32 n_left_from, next_index, * from, * to_next;
+
+    from = vlib_frame_vector_args (from_frame);
+    n_left_from = from_frame->n_vectors;
+
+    next_index = node->cached_next_index;
+
+    while (n_left_from > 0)
+    {
+        u32 n_left_to_next;
+
+        vlib_get_next_frame(vm, node, next_index, to_next, n_left_to_next);
+
+        while (n_left_from >= 4 && n_left_to_next > 2)
+        {
+            const l2_bridge_dpo_t *l2b0, *l2b1;
+            u32 bi0, l2bi0, bi1, l2bi1;
+            vlib_buffer_t *b0, *b1;
+            u8 len0, len1;
+
+            bi0 = from[0];
+            to_next[0] = bi0;
+            bi1 = from[1];
+            to_next[1] = bi1;
+            from += 2;
+            to_next += 2;
+            n_left_from -= 2;
+            n_left_to_next -= 2;
+
+            b0 = vlib_get_buffer (vm, bi0);
+            b1 = vlib_get_buffer (vm, bi1);
+
+            l2bi0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];
+            l2bi1 = vnet_buffer(b1)->ip.adj_index[VLIB_TX];
+            l2b0 = l2_bridge_dpo_get(l2bi0);
+            l2b1 = l2_bridge_dpo_get(l2bi1);
+
+            vnet_buffer(b0)->sw_if_index[VLIB_TX] = l2b0->l2b_sw_if_index;
+            vnet_buffer(b1)->sw_if_index[VLIB_TX] = l2b1->l2b_sw_if_index;
+
+            len0 = ((u8*)vlib_buffer_get_current(b0) -
+                    (u8*)ethernet_buffer_get_header(b0));
+            len1 = ((u8*)vlib_buffer_get_current(b1) -
+                    (u8*)ethernet_buffer_get_header(b1));
+            vnet_buffer(b0)->l2.l2_len = len0;
+            vnet_buffer(b1)->l2.l2_len = len1;
+
+            vlib_buffer_advance(b0, -len0);
+            vlib_buffer_advance(b1, -len1);
+
+            if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
+            {
+                l2_bridge_dpo_trace_t *tr0;
+
+                tr0 = vlib_add_trace (vm, node, b0, sizeof (*tr0));
+                tr0->sw_if_index = l2b0->l2b_sw_if_index;
+            }
+            if (PREDICT_FALSE(b1->flags & VLIB_BUFFER_IS_TRACED))
+            {
+                l2_bridge_dpo_trace_t *tr1;
+
+                tr1 = vlib_add_trace (vm, node, b1, sizeof (*tr1));
+                tr1->sw_if_index = l2b1->l2b_sw_if_index;
+            }
+
+            vlib_validate_buffer_enqueue_x2(vm, node, next_index, to_next,
+                                            n_left_to_next, bi0, bi1,
+                                            L2_BRIDGE_DPO_OUTPUT,
+                                            L2_BRIDGE_DPO_OUTPUT);
+        }
+
+        while (n_left_from > 0 && n_left_to_next > 0)
+        {
+            const l2_bridge_dpo_t * l2b0;
+            vlib_buffer_t * b0;
+            u32 bi0, l2bi0;
+            u8 len0;
+
+            bi0 = from[0];
+            to_next[0] = bi0;
+            from += 1;
+            to_next += 1;
+            n_left_from -= 1;
+            n_left_to_next -= 1;
+
+            b0 = vlib_get_buffer (vm, bi0);
+
+            l2bi0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];
+            l2b0 = l2_bridge_dpo_get(l2bi0);
+
+            vnet_buffer(b0)->sw_if_index[VLIB_TX] = l2b0->l2b_sw_if_index;
+
+            /*
+             * take that, and rewind it back...
+             */
+            len0 = ((u8*)vlib_buffer_get_current(b0) -
+                    (u8*)ethernet_buffer_get_header(b0));
+            vnet_buffer(b0)->l2.l2_len = len0;
+            vlib_buffer_advance(b0, -len0);
+
+            if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
+            {
+                l2_bridge_dpo_trace_t *tr;
+
+                tr = vlib_add_trace (vm, node, b0, sizeof (*tr));
+                tr->sw_if_index = l2b0->l2b_sw_if_index;
+            }
+
+            vlib_validate_buffer_enqueue_x1(vm, node, next_index, to_next,
+                                            n_left_to_next, bi0,
+                                            L2_BRIDGE_DPO_OUTPUT);
+        }
+        vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+    return from_frame->n_vectors;
+}
+
+static u8 *
+format_l2_bridge_dpo_trace (u8 * s, va_list * args)
+{
+    CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+    CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+    l2_bridge_dpo_trace_t * t = va_arg (*args, l2_bridge_dpo_trace_t *);
+    uword indent = format_get_indent (s);
+    s = format (s, "%U sw_if_index:%d",
+                format_white_space, indent,
+                t->sw_if_index);
+    return s;
+}
+
+static uword
+l2_bridge_dpo_l2 (vlib_main_t * vm,
+                  vlib_node_runtime_t * node,
+                  vlib_frame_t * from_frame)
+{
+    return (l2_bridge_dpo_inline(vm, node, from_frame));
+}
+
+
+VLIB_REGISTER_NODE (l2_bridge_dpo_l2_node) = {
+    .function = l2_bridge_dpo_l2,
+    .name = "l2-bridge-dpo",
+    .vector_size = sizeof (u32),
+    .format_trace = format_l2_bridge_dpo_trace,
+
+    .n_next_nodes = 2,
+    .next_nodes = {
+        [L2_BRIDGE_DPO_DROP] = "error-drop",
+        [L2_BRIDGE_DPO_OUTPUT] = "l2-output",
+    },
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (l2_bridge_dpo_l2_node,
+                              l2_bridge_dpo_l2)
diff --git a/src/vnet/dpo/l2_bridge_dpo.h b/src/vnet/dpo/l2_bridge_dpo.h
new file mode 100644
index 00000000000..0a20dd79335
--- /dev/null
+++ b/src/vnet/dpo/l2_bridge_dpo.h
@@ -0,0 +1,56 @@
+/*
+ * 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.
+ */
+
+#ifndef __L2_BRIDGE_DPO_H__
+#define __L2_BRIDGE_DPO_H__
+
+#include <vnet/dpo/dpo.h>
+
+/**
+ * @brief
+ * The data-path object representing an L2 bridge.
+ * If a packet encounters an object of this type in the L3 data-path, it
+ * is injected back into the L2 bridge.
+ */
+typedef struct l2_bridge_dpo_t_
+{
+    /**
+     * The Software interface index that the packets will output on
+     */
+    u32 l2b_sw_if_index;
+
+    /**
+     * number of locks.
+     */
+    u16 l2b_locks;
+} l2_bridge_dpo_t;
+
+extern void l2_bridge_dpo_add_or_lock (u32 sw_if_index,
+                                       dpo_id_t *dpo);
+
+extern void l2_bridge_dpo_module_init(void);
+
+/**
+ * @brief pool of all interface DPOs
+ */
+l2_bridge_dpo_t *l2_bridge_dpo_pool;
+
+static inline l2_bridge_dpo_t *
+l2_bridge_dpo_get (index_t index)
+{
+    return (pool_elt_at_index(l2_bridge_dpo_pool, index));
+}
+
+#endif