L2 Emulation

L2 Emulation is a feautre that is applied to L2 ports to 'extract'
IP packets from the L2 path and inject them into the L3 path (i.e.
into the appropriate ip[4|6]_input node).
L3 routes in the table_id for that interface should then be configured
as DVR routes, therefore the forwarded packet has the L2 header
preserved and togehter the L3 routed system behaves like an L2 bridge.

Change-Id: I8effd7e2f4c67ee277b73c7bc79aa3e5a3e34d03
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 485 insertions, 0 deletions

diff --git a/src/plugins/l2e/l2e.c b/src/plugins/l2e/l2e.c
new file mode 100644
index 00000000000..633d1f92838
--- /dev/null
+++ b/src/plugins/l2e/l2e.c
@@ -0,0 +1,485 @@
+/*
+ * l2_emulation.h : Extract L3 packets from the L2 input and feed
+ *                   them into the L3 path.
+ *
+ * Copyright (c) 2013 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 <plugins/l2e/l2e.h>
+#include <vnet/l2/l2_input.h>
+
+/**
+ * Grouping of global data for the L2 emulation feature
+ */
+typedef struct l2_emulation_main_t_
+{
+  /**
+   * Next nodes for L2 output features
+   */
+  u32 l2_input_feat_next[32];
+} l2_emulation_main_t;
+
+static l2_emulation_main_t l2_emulation_main;
+
+/**
+ * Per-interface L2 configuration
+ */
+typedef struct l2_emulation_t_
+{
+  /**
+   * Enabled or Disabled.
+   *  this is required since one L3 protocl can be enabled, but others not
+   */
+  u8 enabled;
+} l2_emulation_t;
+
+/**
+ * A zero'd out struct we can use in the vec_validate
+ */
+static const l2_emulation_t ezero = { };
+
+/**
+ * Per-interface vector of emulation configs
+ */
+l2_emulation_t *l2_emulations;
+
+void
+l2_emulation_enable (u32 sw_if_index)
+{
+  vec_validate_init_empty (l2_emulations, sw_if_index, ezero);
+
+  l2_emulation_t *l23e = &l2_emulations[sw_if_index];
+
+  l23e->enabled = 1;
+
+  /*
+   * L3 enable the interface - using IP unnumbered from the control
+   * plane may not be possible since there may be no BVI interface
+   * to which to unnumber
+   */
+  ip4_sw_interface_enable_disable (sw_if_index, 1);
+  ip6_sw_interface_enable_disable (sw_if_index, 1);
+
+  l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_L2_EMULATION, 1);
+}
+
+
+void
+l2_emulation_disable (u32 sw_if_index)
+{
+  if (vec_len (l2_emulations) >= sw_if_index)
+    {
+      l2_emulation_t *l23e = &l2_emulations[sw_if_index];
+      memset (l23e, 0, sizeof (*l23e));
+
+      l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_L2_EMULATION, 0);
+      ip4_sw_interface_enable_disable (sw_if_index, 0);
+      ip6_sw_interface_enable_disable (sw_if_index, 0);
+    }
+}
+
+static clib_error_t *
+l2_emulation_interface_add_del (vnet_main_t * vnm,
+				u32 sw_if_index, u32 is_add)
+{
+  if (is_add)
+    {
+      vec_validate_init_empty (l2_emulations, sw_if_index, ezero);
+    }
+
+  return (NULL);
+}
+
+VNET_SW_INTERFACE_ADD_DEL_FUNCTION (l2_emulation_interface_add_del);
+
+static clib_error_t *
+l2_emulation_cli (vlib_main_t * vm,
+		  unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 sw_if_index = ~0;
+  u8 enable = 1;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "%U", unformat_vnet_sw_interface,
+		    vnm, &sw_if_index))
+	;
+      else if (unformat (input, "enable"))
+	enable = 1;
+      else if (unformat (input, "disable"))
+	enable = 0;
+      else
+	break;
+    }
+
+  if (~0 == sw_if_index)
+    return clib_error_return (0, "interface must be specified");
+
+  if (enable)
+    l2_emulation_enable (sw_if_index);
+  else
+    l2_emulation_disable (sw_if_index);
+
+  return (NULL);
+}
+
+/*?
+ * Configure l2 emualtion.
+ *  When the interface is in L2 mode, configure the extraction of L3
+ *  packets out of the L2 path and into the L3 path.
+ *
+ * @cliexpar
+ * @cliexstart{set interface l2 input l2-emulation <interface-name> [disable]
+ * @cliexend
+ ?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (l2_emulation_cli_node, static) = {
+  .path = "set interface l2 l2-emulation",
+  .short_help =
+  "set interface l2 l2-emulation <interface-name> [disable|enable]\n",
+  .function = l2_emulation_cli,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+l2_emulation_show (vlib_main_t * vm,
+		   unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  l2_emulation_t *l23e;
+  u32 sw_if_index;
+
+  vec_foreach_index (sw_if_index, l2_emulations)
+  {
+    l23e = &l2_emulations[sw_if_index];
+    if (l23e->enabled)
+      {
+	vlib_cli_output (vm, "%U\n",
+			 format_vnet_sw_if_index_name, vnm, sw_if_index);
+      }
+  }
+  return (NULL);
+}
+
+/*?
+ * Show l2 emulation.
+ *  When the interface is in L2 mode, configure the extraction of L3
+ *  packets out of the L2 path and into the L3 path.
+ *
+ * @cliexpar
+ * @cliexstart{show interface l2 l2-emulation
+ * @cliexend
+ ?*/
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (l2_emulation_show_node, static) = {
+  .path = "show interface l2 l2-emulation",
+  .short_help = "show interface l2 l2-emulation\n",
+  .function = l2_emulation_show,
+};
+/* *INDENT-ON* */
+
+#define foreach_l2_emulation                    \
+  _(IP4, "Extract IPv4")                        \
+  _(IP6, "Extract IPv6")
+
+typedef enum
+{
+#define _(sym,str) L2_EMULATION_ERROR_##sym,
+  foreach_l2_emulation
+#undef _
+    L2_EMULATION_N_ERROR,
+} l2_emulation_error_t;
+
+static char *l2_emulation_error_strings[] = {
+#define _(sym,string) string,
+  foreach_l2_emulation
+#undef _
+};
+
+typedef enum
+{
+#define _(sym,str) L2_EMULATION_NEXT_##sym,
+  foreach_l2_emulation
+#undef _
+    L2_EMULATION_N_NEXT,
+} l2_emulation_next_t;
+
+/**
+ * per-packet trace data
+ */
+typedef struct l2_emulation_trace_t_
+{
+  /* per-pkt trace data */
+  u8 extracted;
+} l2_emulation_trace_t;
+
+static uword
+l2_emulation_node_fn (vlib_main_t * vm,
+		      vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  l2_emulation_main_t *em = &l2_emulation_main;
+  u32 n_left_from, *from, *to_next;
+  l2_emulation_next_t next_index;
+  u32 ip4_hits = 0;
+  u32 ip6_hits = 0;
+
+  next_index = 0;
+  n_left_from = frame->n_vectors;
+  from = vlib_frame_vector_args (frame);
+
+  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)
+	{
+	  vlib_buffer_t *b0, *b1;
+	  u32 sw_if_index0, sw_if_index1;
+	  u16 ether_type0, ether_type1;
+	  u32 next0 = ~0, next1 = ~0;
+	  u8 l2_len0, l2_len1;
+	  u32 bi0, bi1;
+	  u8 *h0, *h1;
+
+	  bi0 = to_next[0] = from[0];
+	  bi1 = to_next[1] = from[1];
+
+	  from += 2;
+	  n_left_from -= 2;
+	  to_next += 2;
+	  n_left_to_next -= 2;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  b1 = vlib_get_buffer (vm, bi1);
+	  l2_len0 = vnet_buffer (b0)->l2.l2_len;
+	  l2_len1 = vnet_buffer (b1)->l2.l2_len;
+
+	  h0 = vlib_buffer_get_current (b0);
+	  h1 = vlib_buffer_get_current (b1);
+
+	  ether_type0 = clib_net_to_host_u16 (*(u16 *) (h0 + l2_len0 - 2));
+	  ether_type1 = clib_net_to_host_u16 (*(u16 *) (h1 + l2_len1 - 2));
+	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+	  sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
+
+	  /*
+	   * only extract unicast
+	   */
+	  if (PREDICT_TRUE (!(h0[0] & 0x1)))
+	    {
+	      switch (ether_type0)
+		{
+		case ETHERNET_TYPE_IP4:
+		  ASSERT (l2_emulations[sw_if_index0].enabled);
+		  ++ip4_hits;
+		  next0 = L2_EMULATION_NEXT_IP4;
+		  vlib_buffer_advance (b0, l2_len0);
+		  break;
+		case ETHERNET_TYPE_IP6:
+		  ASSERT (l2_emulations[sw_if_index0].enabled);
+		  ++ip6_hits;
+		  next0 = L2_EMULATION_NEXT_IP6;
+		  vlib_buffer_advance (b0, l2_len0);
+		default:
+		  break;
+		}
+	    }
+	  if (PREDICT_TRUE (!(h1[0] & 0x1)))
+	    {
+	      switch (ether_type1)
+		{
+		case ETHERNET_TYPE_IP4:
+		  ASSERT (l2_emulations[sw_if_index1].enabled);
+		  ++ip4_hits;
+		  next1 = L2_EMULATION_NEXT_IP4;
+		  vlib_buffer_advance (b1, l2_len1);
+		  break;
+		case ETHERNET_TYPE_IP6:
+		  ASSERT (l2_emulations[sw_if_index1].enabled);
+		  ++ip6_hits;
+		  next1 = L2_EMULATION_NEXT_IP6;
+		  vlib_buffer_advance (b1, l2_len1);
+		default:
+		  break;
+		}
+	    }
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      l2_emulation_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->extracted = (next0 != ~0);
+	    }
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b1->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      l2_emulation_trace_t *t =
+		vlib_add_trace (vm, node, b1, sizeof (*t));
+	      t->extracted = (next1 != ~0);
+	    }
+
+	  /* Determine the next node and remove ourself from bitmap */
+	  if (PREDICT_TRUE (next0 == ~0))
+	    next0 = vnet_l2_feature_next (b0, em->l2_input_feat_next,
+					  L2INPUT_FEAT_L2_EMULATION);
+
+	  /* Determine the next node and remove ourself from bitmap */
+	  if (PREDICT_TRUE (next1 == ~0))
+	    next1 = vnet_l2_feature_next (b1, em->l2_input_feat_next,
+					  L2INPUT_FEAT_L2_EMULATION);
+
+	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, bi1, next0, next1);
+	}
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  vlib_buffer_t *b0;
+	  u32 sw_if_index0;
+	  u16 ether_type0;
+	  u32 next0 = ~0;
+	  u8 l2_len0;
+	  u32 bi0;
+	  u8 *h0;
+
+	  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);
+	  l2_len0 = vnet_buffer (b0)->l2.l2_len;
+
+	  h0 = vlib_buffer_get_current (b0);
+	  ether_type0 = clib_net_to_host_u16 (*(u16 *) (h0 + l2_len0 - 2));
+	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+
+	  /*
+	   * only extract unicast
+	   */
+	  if (PREDICT_TRUE (!(h0[0] & 0x1)))
+	    {
+	      switch (ether_type0)
+		{
+		case ETHERNET_TYPE_IP4:
+		  ASSERT (l2_emulations[sw_if_index0].enabled);
+		  ++ip4_hits;
+		  next0 = L2_EMULATION_NEXT_IP4;
+		  vlib_buffer_advance (b0, l2_len0);
+		  break;
+		case ETHERNET_TYPE_IP6:
+		  ASSERT (l2_emulations[sw_if_index0].enabled);
+		  ++ip6_hits;
+		  next0 = L2_EMULATION_NEXT_IP6;
+		  vlib_buffer_advance (b0, l2_len0);
+		default:
+		  break;
+		}
+	    }
+
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      l2_emulation_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->extracted = (next0 != ~0);
+	    }
+
+	  /* Determine the next node and remove ourself from bitmap */
+	  if (PREDICT_TRUE (next0 == ~0))
+	    next0 = vnet_l2_feature_next (b0, em->l2_input_feat_next,
+					  L2INPUT_FEAT_L2_EMULATION);
+
+	  /* verify speculative enqueue, maybe switch current next frame */
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  vlib_node_increment_counter (vm, node->node_index,
+			       L2_EMULATION_ERROR_IP4, ip4_hits);
+  vlib_node_increment_counter (vm, node->node_index,
+			       L2_EMULATION_ERROR_IP6, ip6_hits);
+
+  return frame->n_vectors;
+}
+
+/* packet trace format function */
+static u8 *
+format_l2_emulation_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_emulation_trace_t *t = va_arg (*args, l2_emulation_trace_t *);
+
+  s = format (s, "l2-emulation: %s", (t->extracted ? "yes" : "no"));
+
+  return s;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (l2_emulation_node) = {
+  .function = l2_emulation_node_fn,
+  .name = "l2-emulation",
+  .vector_size = sizeof (u32),
+  .format_trace = format_l2_emulation_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(l2_emulation_error_strings),
+  .error_strings = l2_emulation_error_strings,
+
+  .n_next_nodes = L2_EMULATION_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [L2_EMULATION_NEXT_IP4] = "ip4-input",
+    [L2_EMULATION_NEXT_IP6] = "ip6-input",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (l2_emulation_node, l2_emulation_node_fn);
+
+
+static clib_error_t *
+l2_emulation_init (vlib_main_t * vm)
+{
+  l2_emulation_main_t *em = &l2_emulation_main;
+
+  /* Initialize the feature next-node indexes */
+  feat_bitmap_init_next_nodes (vm,
+			       l2_emulation_node.index,
+			       L2INPUT_N_FEAT,
+			       l2input_get_feat_names (),
+			       em->l2_input_feat_next);
+
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (l2_emulation_init);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */