Add basic support for DS-Lite CE (VPP-1059)

Change-Id: Ifcca60da3f77c0a4959f98b3365c846badbdc2d0
Signed-off-by: Juraj Sloboda <jsloboda@cisco.com>

11 files changed, 683 insertions, 13 deletions

diff --git a/src/plugins/nat.am b/src/plugins/nat.am
index a0e0568a5a1..fa3c4b9fbc3 100644
--- a/src/plugins/nat.am
+++ b/src/plugins/nat.am
@@ -33,7 +33,9 @@ nat_plugin_la_SOURCES = nat/nat.c		\
         nat/dslite.c                         	\
         nat/dslite_in2out.c                  	\
         nat/dslite_out2in.c                  	\
-        nat/dslite_cli.c
+        nat/dslite_cli.c                        \
+        nat/dslite_ce_encap.c                   \
+        nat/dslite_ce_decap.c
 
 API_FILES += nat/nat.api
 
diff --git a/src/plugins/nat/dslite.c b/src/plugins/nat/dslite.c
index c86cc8d7e1d..12c813200ec 100644
--- a/src/plugins/nat/dslite.c
+++ b/src/plugins/nat/dslite.c
@@ -65,24 +65,47 @@ dslite_init (vlib_main_t * vm)
     }
   /* *INDENT-ON* */
 
+  dm->is_ce = 0;
+
   dslite_dpo_module_init ();
 }
 
+void
+dslite_set_ce (dslite_main_t * dm, u8 set)
+{
+  dm->is_ce = (set != 0);
+}
+
 int
 dslite_set_aftr_ip6_addr (dslite_main_t * dm, ip6_address_t * addr)
 {
-  dpo_id_t dpo_v6 = DPO_INVALID;
+  dpo_id_t dpo = DPO_INVALID;
 
-  dslite_dpo_create (DPO_PROTO_IP6, 0, &dpo_v6);
-  fib_prefix_t pfx = {
-    .fp_proto = FIB_PROTOCOL_IP6,
-    .fp_len = 128,
-    .fp_addr.ip6.as_u64[0] = addr->as_u64[0],
-    .fp_addr.ip6.as_u64[1] = addr->as_u64[1],
-  };
-  fib_table_entry_special_dpo_add (0, &pfx, FIB_SOURCE_PLUGIN_HI,
-				   FIB_ENTRY_FLAG_EXCLUSIVE, &dpo_v6);
-  dpo_reset (&dpo_v6);
+  if (dm->is_ce)
+    {
+      dslite_ce_dpo_create (DPO_PROTO_IP4, 0, &dpo);
+      fib_prefix_t pfx = {
+	.fp_proto = FIB_PROTOCOL_IP4,
+	.fp_len = 0,
+	.fp_addr.ip4.as_u32 = 0,
+      };
+      fib_table_entry_special_dpo_add (0, &pfx, FIB_SOURCE_PLUGIN_HI,
+				       FIB_ENTRY_FLAG_EXCLUSIVE, &dpo);
+    }
+  else
+    {
+      dslite_dpo_create (DPO_PROTO_IP6, 0, &dpo);
+      fib_prefix_t pfx = {
+	.fp_proto = FIB_PROTOCOL_IP6,
+	.fp_len = 128,
+	.fp_addr.ip6.as_u64[0] = addr->as_u64[0],
+	.fp_addr.ip6.as_u64[1] = addr->as_u64[1],
+      };
+      fib_table_entry_special_dpo_add (0, &pfx, FIB_SOURCE_PLUGIN_HI,
+				       FIB_ENTRY_FLAG_EXCLUSIVE, &dpo);
+    }
+
+  dpo_reset (&dpo);
 
   dm->aftr_ip6_addr.as_u64[0] = addr->as_u64[0];
   dm->aftr_ip6_addr.as_u64[1] = addr->as_u64[1];
@@ -90,6 +113,58 @@ dslite_set_aftr_ip6_addr (dslite_main_t * dm, ip6_address_t * addr)
 }
 
 int
+dslite_set_aftr_ip4_addr (dslite_main_t * dm, ip4_address_t * addr)
+{
+  dm->aftr_ip4_addr.as_u32 = addr->as_u32;
+  return 0;
+}
+
+int
+dslite_set_b4_ip6_addr (dslite_main_t * dm, ip6_address_t * addr)
+{
+  if (dm->is_ce)
+    {
+      dpo_id_t dpo = DPO_INVALID;
+
+      dslite_ce_dpo_create (DPO_PROTO_IP6, 0, &dpo);
+      fib_prefix_t pfx = {
+	.fp_proto = FIB_PROTOCOL_IP6,
+	.fp_len = 128,
+	.fp_addr.ip6.as_u64[0] = addr->as_u64[0],
+	.fp_addr.ip6.as_u64[1] = addr->as_u64[1],
+      };
+      fib_table_entry_special_dpo_add (0, &pfx, FIB_SOURCE_PLUGIN_HI,
+				       FIB_ENTRY_FLAG_EXCLUSIVE, &dpo);
+
+      dpo_reset (&dpo);
+
+      dm->b4_ip6_addr.as_u64[0] = addr->as_u64[0];
+      dm->b4_ip6_addr.as_u64[1] = addr->as_u64[1];
+    }
+  else
+    {
+      return VNET_API_ERROR_FEATURE_DISABLED;
+    }
+
+  return 0;
+}
+
+int
+dslite_set_b4_ip4_addr (dslite_main_t * dm, ip4_address_t * addr)
+{
+  if (dm->is_ce)
+    {
+      dm->b4_ip4_addr.as_u32 = addr->as_u32;
+    }
+  else
+    {
+      return VNET_API_ERROR_FEATURE_DISABLED;
+    }
+
+  return 0;
+}
+
+int
 dslite_add_del_pool_addr (dslite_main_t * dm, ip4_address_t * addr, u8 is_add)
 {
   vlib_thread_main_t *tm = vlib_get_thread_main ();
@@ -155,6 +230,18 @@ format_dslite_trace (u8 * s, va_list * args)
   return s;
 }
 
+u8 *
+format_dslite_ce_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 *);
+  dslite_ce_trace_t *t = va_arg (*args, dslite_ce_trace_t *);
+
+  s = format (s, "next index %d", t->next_index);
+
+  return s;
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/plugins/nat/dslite.h b/src/plugins/nat/dslite.h
index 4b7089b3190..6a1c2ecd709 100644
--- a/src/plugins/nat/dslite.h
+++ b/src/plugins/nat/dslite.h
@@ -80,11 +80,17 @@ typedef struct
 {
   ip6_address_t aftr_ip6_addr;
   ip4_address_t aftr_ip4_addr;
+  ip6_address_t b4_ip6_addr;
+  ip4_address_t b4_ip4_addr;
   dslite_per_thread_data_t *per_thread_data;
   snat_address_t *addr_pool;
   u32 num_workers;
   u32 first_worker_index;
   u16 port_per_thread;
+
+  /* If set then the DSLite component behaves as CPE/B4
+   * otherwise it behaves as AFTR */
+  u8 is_ce;
 } dslite_main_t;
 
 typedef struct
@@ -93,9 +99,16 @@ typedef struct
   u32 session_index;
 } dslite_trace_t;
 
+typedef struct
+{
+  u32 next_index;
+} dslite_ce_trace_t;
+
 #define foreach_dslite_error                    \
 _(IN2OUT, "valid in2out DS-Lite packets")       \
 _(OUT2IN, "valid out2in DS-Lite packets")       \
+_(CE_ENCAP, "valid CE encap DS-Lite packets")   \
+_(CE_DECAP, "valid CE decap DS-Lite packets")   \
 _(NO_TRANSLATION, "no translation")             \
 _(BAD_IP6_PROTOCOL, "bad ip6 protocol")         \
 _(OUT_OF_PORTS, "out of ports")                 \
@@ -115,12 +128,19 @@ extern dslite_main_t dslite_main;
 extern vlib_node_registration_t dslite_in2out_node;
 extern vlib_node_registration_t dslite_in2out_slowpath_node;
 extern vlib_node_registration_t dslite_out2in_node;
+extern vlib_node_registration_t dslite_ce_encap_node;
+extern vlib_node_registration_t dslite_ce_decap_node;
 
 void dslite_init (vlib_main_t * vm);
+void dslite_set_ce (dslite_main_t * dm, u8 set);
 int dslite_set_aftr_ip6_addr (dslite_main_t * dm, ip6_address_t * addr);
+int dslite_set_b4_ip6_addr (dslite_main_t * dm, ip6_address_t * addr);
+int dslite_set_aftr_ip4_addr (dslite_main_t * dm, ip4_address_t * addr);
+int dslite_set_b4_ip4_addr (dslite_main_t * dm, ip4_address_t * addr);
 int dslite_add_del_pool_addr (dslite_main_t * dm, ip4_address_t * addr,
 			      u8 is_add);
 u8 *format_dslite_trace (u8 * s, va_list * args);
+u8 *format_dslite_ce_trace (u8 * s, va_list * args);
 
 #endif /* __included_dslite_h__ */
 
diff --git a/src/plugins/nat/dslite_ce_decap.c b/src/plugins/nat/dslite_ce_decap.c
new file mode 100644
index 00000000000..615a424e871
--- /dev/null
+++ b/src/plugins/nat/dslite_ce_decap.c
@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2018 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 <nat/dslite.h>
+
+vlib_node_registration_t dslite_ce_decap_node;
+
+typedef enum
+{
+  DSLITE_CE_DECAP_NEXT_IP4_LOOKUP,
+  DSLITE_IN2OUT_NEXT_IP6_ICMP,
+  DSLITE_CE_DECAP_NEXT_DROP,
+  DSLITE_CE_DECAP_N_NEXT,
+} dslite_ce_decap_next_t;
+
+static char *dslite_ce_decap_error_strings[] = {
+#define _(sym,string) string,
+  foreach_dslite_error
+#undef _
+};
+
+static uword
+dslite_ce_decap_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
+			 vlib_frame_t * frame)
+{
+  u32 n_left_from, *from, *to_next;
+  dslite_ce_decap_next_t next_index;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_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 > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0 = DSLITE_CE_DECAP_NEXT_IP4_LOOKUP;
+	  u8 error0 = DSLITE_ERROR_CE_DECAP;
+	  ip4_header_t *ip40;
+	  ip6_header_t *ip60;
+	  u32 proto0;
+
+	  /* speculatively enqueue b0 to the current next frame */
+	  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);
+	  ip60 = vlib_buffer_get_current (b0);
+
+	  if (PREDICT_FALSE (ip60->protocol != IP_PROTOCOL_IP_IN_IP))
+	    {
+	      if (ip60->protocol == IP_PROTOCOL_ICMP6)
+		{
+		  next0 = DSLITE_IN2OUT_NEXT_IP6_ICMP;
+		  goto trace0;
+		}
+	      error0 = DSLITE_ERROR_BAD_IP6_PROTOCOL;
+	      next0 = DSLITE_CE_DECAP_NEXT_DROP;
+	      goto trace0;
+	    }
+
+	  ip40 = vlib_buffer_get_current (b0) + sizeof (ip6_header_t);
+	  proto0 = ip_proto_to_snat_proto (ip40->protocol);
+
+	  if (PREDICT_FALSE (proto0 == ~0))
+	    {
+	      error0 = DSLITE_ERROR_UNSUPPORTED_PROTOCOL;
+	      next0 = DSLITE_CE_DECAP_NEXT_DROP;
+	      goto trace0;
+	    }
+
+	  ip40->tos =
+	    (clib_net_to_host_u32
+	     (ip60->ip_version_traffic_class_and_flow_label) & 0x0ff00000) >>
+	    20;
+	  vlib_buffer_advance (b0, sizeof (ip6_header_t));
+
+	trace0:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      dslite_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->next_index = next0;
+	    }
+
+	  b0->error = node->errors[error0];
+
+	  /* 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);
+    }
+
+  return frame->n_vectors;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (dslite_ce_decap_node) = {
+  .function = dslite_ce_decap_node_fn,
+  .name = "dslite-ce-decap",
+  .vector_size = sizeof (u32),
+  .format_trace = format_dslite_ce_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (dslite_ce_decap_error_strings),
+  .error_strings = dslite_ce_decap_error_strings,
+  .n_next_nodes = DSLITE_CE_DECAP_N_NEXT,
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [DSLITE_CE_DECAP_NEXT_DROP] = "error-drop",
+    [DSLITE_CE_DECAP_NEXT_IP4_LOOKUP] = "ip4-lookup",
+    [DSLITE_IN2OUT_NEXT_IP6_ICMP] = "ip6-icmp-input",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (dslite_ce_decap_node, dslite_ce_decap_node_fn);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/nat/dslite_ce_encap.c b/src/plugins/nat/dslite_ce_encap.c
new file mode 100644
index 00000000000..f098d75ca70
--- /dev/null
+++ b/src/plugins/nat/dslite_ce_encap.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2018 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 <nat/dslite.h>
+
+vlib_node_registration_t dslite_ce_encap_node;
+
+typedef enum
+{
+  DSLITE_CE_ENCAP_NEXT_IP6_LOOKUP,
+  DSLITE_CE_ENCAP_NEXT_DROP,
+  DSLITE_CE_ENCAP_N_NEXT,
+} dslite_ce_encap_next_t;
+
+static char *dslite_ce_encap_error_strings[] = {
+#define _(sym,string) string,
+  foreach_dslite_error
+#undef _
+};
+
+static uword
+dslite_ce_encap_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
+			 vlib_frame_t * frame)
+{
+  u32 n_left_from, *from, *to_next;
+  dslite_ce_encap_next_t next_index;
+  dslite_main_t *dm = &dslite_main;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_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 > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0 = DSLITE_CE_ENCAP_NEXT_IP6_LOOKUP;
+	  u8 error0 = DSLITE_ERROR_CE_ENCAP;
+	  ip4_header_t *ip40;
+	  ip6_header_t *ip60;
+	  u32 proto0;
+
+	  /* speculatively enqueue b0 to the current next frame */
+	  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);
+	  ip40 = vlib_buffer_get_current (b0);
+	  proto0 = ip_proto_to_snat_proto (ip40->protocol);
+
+	  if (PREDICT_FALSE (proto0 == ~0))
+	    {
+	      error0 = DSLITE_ERROR_UNSUPPORTED_PROTOCOL;
+	      next0 = DSLITE_CE_ENCAP_NEXT_DROP;
+	      goto trace0;
+	    }
+
+	  /* Construct IPv6 header */
+	  vlib_buffer_advance (b0, -(sizeof (ip6_header_t)));
+	  ip60 = vlib_buffer_get_current (b0);
+	  ip60->ip_version_traffic_class_and_flow_label =
+	    clib_host_to_net_u32 ((6 << 28) + (ip40->tos << 20));
+	  ip60->payload_length = ip40->length;
+	  ip60->protocol = IP_PROTOCOL_IP_IN_IP;
+	  ip60->hop_limit = ip40->ttl;
+	  ip60->dst_address.as_u64[0] = dm->aftr_ip6_addr.as_u64[0];
+	  ip60->dst_address.as_u64[1] = dm->aftr_ip6_addr.as_u64[1];
+	  ip60->src_address.as_u64[0] = dm->b4_ip6_addr.as_u64[0];
+	  ip60->src_address.as_u64[1] = dm->b4_ip6_addr.as_u64[1];
+
+	trace0:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      dslite_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->next_index = next0;
+	    }
+
+	  b0->error = node->errors[error0];
+
+	  /* 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);
+    }
+
+  return frame->n_vectors;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (dslite_ce_encap_node) = {
+  .function = dslite_ce_encap_node_fn,
+  .name = "dslite-ce-encap",
+  .vector_size = sizeof (u32),
+  .format_trace = format_dslite_ce_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (dslite_ce_encap_error_strings),
+  .error_strings = dslite_ce_encap_error_strings,
+  .n_next_nodes = DSLITE_CE_ENCAP_N_NEXT,
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [DSLITE_CE_ENCAP_NEXT_DROP] = "error-drop",
+    [DSLITE_CE_ENCAP_NEXT_IP6_LOOKUP] = "ip6-lookup",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (dslite_ce_encap_node, dslite_ce_encap_node_fn);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/nat/dslite_cli.c b/src/plugins/nat/dslite_cli.c
index 7282762ebfc..f600c0350d6 100644
--- a/src/plugins/nat/dslite_cli.c
+++ b/src/plugins/nat/dslite_cli.c
@@ -161,6 +161,56 @@ dslite_show_aftr_ip6_addr_command_fn (vlib_main_t * vm,
   return 0;
 }
 
+static clib_error_t *
+dslite_set_b4_tunnel_addr_command_fn (vlib_main_t * vm,
+				      unformat_input_t * input,
+				      vlib_cli_command_t * cmd)
+{
+  dslite_main_t *dm = &dslite_main;
+  unformat_input_t _line_input, *line_input = &_line_input;
+  ip6_address_t ip6_addr;
+  int rv;
+  clib_error_t *error = 0;
+
+  /* Get a line of input. */
+  if (!unformat_user (input, unformat_line_input, line_input))
+    return 0;
+
+  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "%U", unformat_ip6_address, &ip6_addr))
+	;
+      else
+	{
+	  error = clib_error_return (0, "unknown input '%U'",
+				     format_unformat_error, line_input);
+	  goto done;
+	}
+    }
+
+  rv = dslite_set_b4_ip6_addr (dm, &ip6_addr);
+
+  if (rv)
+    error =
+      clib_error_return (0, "Set DS-Lite B4 tunnel endpoint address failed.");
+
+done:
+  unformat_free (line_input);
+
+  return error;
+}
+
+static clib_error_t *
+dslite_show_b4_ip6_addr_command_fn (vlib_main_t * vm,
+				    unformat_input_t * input,
+				    vlib_cli_command_t * cmd)
+{
+  dslite_main_t *dm = &dslite_main;
+
+  vlib_cli_output (vm, "%U", format_ip6_address, &dm->b4_ip6_addr);
+  return 0;
+}
+
 static u8 *
 format_dslite_session (u8 * s, va_list * args)
 {
@@ -263,6 +313,18 @@ VLIB_CLI_COMMAND (dslite_show_aftr_ip6_addr, static) = {
   .function = dslite_show_aftr_ip6_addr_command_fn,
 };
 
+VLIB_CLI_COMMAND (dslite_set_b4_tunnel_addr, static) = {
+  .path = "dslite set b4-tunnel-endpoint-address",
+  .short_help = "dslite set b4-tunnel-endpoint-address <ip6>",
+  .function = dslite_set_b4_tunnel_addr_command_fn,
+};
+
+VLIB_CLI_COMMAND (dslite_show_b4_ip6_addr, static) = {
+  .path = "show dslite b4-tunnel-endpoint-address",
+  .short_help = "show dslite b4-tunnel-endpoint-address",
+  .function = dslite_show_b4_ip6_addr_command_fn,
+};
+
 VLIB_CLI_COMMAND (dslite_show_sessions, static) = {
   .path = "show dslite sessions",
   .short_help = "show dslite sessions",
diff --git a/src/plugins/nat/dslite_dpo.c b/src/plugins/nat/dslite_dpo.c
index 376d7174858..97ebb18cf70 100644
--- a/src/plugins/nat/dslite_dpo.c
+++ b/src/plugins/nat/dslite_dpo.c
@@ -17,6 +17,7 @@
 #include <nat/dslite_dpo.h>
 
 dpo_type_t dslite_dpo_type;
+dpo_type_t dslite_ce_dpo_type;
 
 void
 dslite_dpo_create (dpo_proto_t dproto, u32 aftr_index, dpo_id_t * dpo)
@@ -24,6 +25,12 @@ dslite_dpo_create (dpo_proto_t dproto, u32 aftr_index, dpo_id_t * dpo)
   dpo_set (dpo, dslite_dpo_type, dproto, aftr_index);
 }
 
+void
+dslite_ce_dpo_create (dpo_proto_t dproto, u32 b4_index, dpo_id_t * dpo)
+{
+  dpo_set (dpo, dslite_ce_dpo_type, dproto, b4_index);
+}
+
 u8 *
 format_dslite_dpo (u8 * s, va_list * args)
 {
@@ -33,6 +40,15 @@ format_dslite_dpo (u8 * s, va_list * args)
   return (format (s, "DS-Lite: AFTR:%d", index));
 }
 
+u8 *
+format_dslite_ce_dpo (u8 * s, va_list * args)
+{
+  index_t index = va_arg (*args, index_t);
+  CLIB_UNUSED (u32 indent) = va_arg (*args, u32);
+
+  return (format (s, "DS-Lite: B4:%d", index));
+}
+
 static void
 dslite_dpo_lock (dpo_id_t * dpo)
 {
@@ -43,12 +59,28 @@ dslite_dpo_unlock (dpo_id_t * dpo)
 {
 }
 
+static void
+dslite_ce_dpo_lock (dpo_id_t * dpo)
+{
+}
+
+static void
+dslite_ce_dpo_unlock (dpo_id_t * dpo)
+{
+}
+
 const static dpo_vft_t dslite_dpo_vft = {
   .dv_lock = dslite_dpo_lock,
   .dv_unlock = dslite_dpo_unlock,
   .dv_format = format_dslite_dpo,
 };
 
+const static dpo_vft_t dslite_ce_dpo_vft = {
+  .dv_lock = dslite_ce_dpo_lock,
+  .dv_unlock = dslite_ce_dpo_unlock,
+  .dv_format = format_dslite_ce_dpo,
+};
+
 const static char *const dslite_ip4_nodes[] = {
   "dslite-out2in",
   NULL,
@@ -59,16 +91,34 @@ const static char *const dslite_ip6_nodes[] = {
   NULL,
 };
 
+const static char *const dslite_ce_ip4_nodes[] = {
+  "dslite-ce-encap",
+  NULL,
+};
+
+const static char *const dslite_ce_ip6_nodes[] = {
+  "dslite-ce-decap",
+  NULL,
+};
+
 const static char *const *const dslite_nodes[DPO_PROTO_NUM] = {
   [DPO_PROTO_IP4] = dslite_ip4_nodes,
   [DPO_PROTO_IP6] = dslite_ip6_nodes,
   [DPO_PROTO_MPLS] = NULL,
 };
 
+const static char *const *const dslite_ce_nodes[DPO_PROTO_NUM] = {
+  [DPO_PROTO_IP4] = dslite_ce_ip4_nodes,
+  [DPO_PROTO_IP6] = dslite_ce_ip6_nodes,
+  [DPO_PROTO_MPLS] = NULL,
+};
+
 void
 dslite_dpo_module_init (void)
 {
   dslite_dpo_type = dpo_register_new_type (&dslite_dpo_vft, dslite_nodes);
+  dslite_ce_dpo_type = dpo_register_new_type (&dslite_ce_dpo_vft,
+					      dslite_ce_nodes);
 }
 
 /*
diff --git a/src/plugins/nat/dslite_dpo.h b/src/plugins/nat/dslite_dpo.h
index ead0e7de610..53d37b27fb4 100644
--- a/src/plugins/nat/dslite_dpo.h
+++ b/src/plugins/nat/dslite_dpo.h
@@ -20,8 +20,10 @@
 #include <vnet/dpo/dpo.h>
 
 void dslite_dpo_create (dpo_proto_t dproto, u32 aftr_index, dpo_id_t * dpo);
+void dslite_ce_dpo_create (dpo_proto_t dproto, u32 b4_index, dpo_id_t * dpo);
 
 u8 *format_dslite_dpo (u8 * s, va_list * args);
+u8 *format_dslite_ce_dpo (u8 * s, va_list * args);
 
 void dslite_dpo_module_init (void);
 
diff --git a/src/plugins/nat/nat.api b/src/plugins/nat/nat.api
index d6a912b72d0..6ebe4e37933 100644
--- a/src/plugins/nat/nat.api
+++ b/src/plugins/nat/nat.api
@@ -1159,9 +1159,72 @@ autoreply define dslite_add_del_pool_addr_range {
   u8 is_add;
 };
 
+/** \brief Set AFTR IPv6 and IPv4 addresses
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param ip4_addr - IPv4 address
+    @param ip6_addr - IP64 address
+*/
 autoreply define dslite_set_aftr_addr {
   u32 client_index;
   u32 context;
   u8 ip4_addr[4];
   u8 ip6_addr[16];
 };
+
+/** \brief Get AFTR IPv6 and IPv4 addresses
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+*/
+define dslite_get_aftr_addr {
+  u32 client_index;
+  u32 context;
+};
+
+/** \brief Response to get AFTR IPv6 and IPv4 addresses
+    @param context - sender context, to match reply w/ request
+    @param retval - return code
+    @param ip4_addr - IPv4 address
+    @param ip6_addr - IP64 address
+*/
+define dslite_get_aftr_addr_reply {
+  u32 context;
+  i32 retval;
+  u8 ip4_addr[4];
+  u8 ip6_addr[16];
+};
+
+/** \brief Set B4 IPv6 and IPv4 addresses
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param ip4_addr - IPv4 address
+    @param ip6_addr - IP64 address
+*/
+autoreply define dslite_set_b4_addr {
+  u32 client_index;
+  u32 context;
+  u8 ip4_addr[4];
+  u8 ip6_addr[16];
+};
+
+/** \brief Get B4 IPv6 and IPv4 addresses
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+*/
+define dslite_get_b4_addr {
+  u32 client_index;
+  u32 context;
+};
+
+/** \brief Response to get B4 IPv6 and IPv4 addresses
+    @param context - sender context, to match reply w/ request
+    @param retval - return code
+    @param ip4_addr - IPv4 address
+    @param ip6_addr - IP64 address
+*/
+define dslite_get_b4_addr_reply {
+  u32 context;
+  i32 retval;
+  u8 ip4_addr[4];
+  u8 ip6_addr[16];
+};
diff --git a/src/plugins/nat/nat.c b/src/plugins/nat/nat.c
index 9993de06128..90515acc5b6 100644
--- a/src/plugins/nat/nat.c
+++ b/src/plugins/nat/nat.c
@@ -2900,6 +2900,7 @@ snat_config (vlib_main_t * vm, unformat_input_t * input)
   u8 static_mapping_only = 0;
   u8 static_mapping_connection_tracking = 0;
   snat_main_per_thread_data_t *tsm;
+  dslite_main_t * dm = &dslite_main;
 
   sm->deterministic = 0;
   sm->out2in_dpo = 0;
@@ -2945,6 +2946,8 @@ snat_config (vlib_main_t * vm, unformat_input_t * input)
         ;
       else if (unformat (input, "out2in dpo"))
         sm->out2in_dpo = 1;
+      else if (unformat (input, "dslite ce"))
+        dslite_set_ce(dm, 1);
       else
 	return clib_error_return (0, "unknown input '%U'",
 				  format_unformat_error, input);
diff --git a/src/plugins/nat/nat_api.c b/src/plugins/nat/nat_api.c
index bc192a782f6..d9f8bbd41be 100644
--- a/src/plugins/nat/nat_api.c
+++ b/src/plugins/nat/nat_api.c
@@ -2385,10 +2385,14 @@ vl_api_dslite_set_aftr_addr_t_handler (vl_api_dslite_set_aftr_addr_t * mp)
   dslite_main_t *dm = &dslite_main;
   int rv = 0;
   ip6_address_t ip6_addr;
+  ip4_address_t ip4_addr;
 
   memcpy (&ip6_addr.as_u8, mp->ip6_addr, 16);
+  memcpy (&ip4_addr.as_u8, mp->ip4_addr, 4);
 
   rv = dslite_set_aftr_ip6_addr (dm, &ip6_addr);
+  if (rv == 0)
+    rv = dslite_set_aftr_ip4_addr (dm, &ip4_addr);
 
   REPLY_MACRO (VL_API_DSLITE_SET_AFTR_ADDR_REPLY);
 }
@@ -2408,6 +2412,96 @@ vl_api_dslite_set_aftr_addr_t_print (vl_api_dslite_set_aftr_addr_t * mp,
 }
 
 static void
+vl_api_dslite_get_aftr_addr_t_handler (vl_api_dslite_get_aftr_addr_t * mp)
+{
+  snat_main_t *sm = &snat_main;
+  vl_api_dslite_get_aftr_addr_reply_t *rmp;
+  dslite_main_t *dm = &dslite_main;
+  int rv = 0;
+
+  /* *INDENT-OFF* */
+  REPLY_MACRO2 (VL_API_DSLITE_GET_AFTR_ADDR_REPLY,
+  ({
+    memcpy (rmp->ip4_addr, &dm->aftr_ip4_addr.as_u8, 4);
+    memcpy (rmp->ip6_addr, &dm->aftr_ip6_addr.as_u8, 16);
+  }))
+  /* *INDENT-ON* */
+}
+
+static void *
+vl_api_dslite_get_aftr_addr_t_print (vl_api_dslite_get_aftr_addr_t * mp,
+				     void *handle)
+{
+  u8 *s;
+
+  s = format (0, "SCRIPT: dslite_get_aftr_addr");
+
+  FINISH;
+}
+
+static void
+vl_api_dslite_set_b4_addr_t_handler (vl_api_dslite_set_b4_addr_t * mp)
+{
+  vl_api_dslite_set_b4_addr_reply_t *rmp;
+  snat_main_t *sm = &snat_main;
+  dslite_main_t *dm = &dslite_main;
+  int rv = 0;
+  ip6_address_t ip6_addr;
+  ip4_address_t ip4_addr;
+
+  memcpy (&ip6_addr.as_u8, mp->ip6_addr, 16);
+  memcpy (&ip4_addr.as_u8, mp->ip4_addr, 4);
+
+  rv = dslite_set_b4_ip6_addr (dm, &ip6_addr);
+  if (rv == 0)
+    rv = dslite_set_b4_ip4_addr (dm, &ip4_addr);
+
+  REPLY_MACRO (VL_API_DSLITE_SET_B4_ADDR_REPLY);
+}
+
+static void *
+vl_api_dslite_set_b4_addr_t_print (vl_api_dslite_set_b4_addr_t * mp,
+				   void *handle)
+{
+  u8 *s;
+
+  s = format (0, "SCRIPT: dslite_set_b4_addr ");
+  s = format (s, "ip6_addr %U ip4_addr %U\n",
+	      format_ip6_address, mp->ip6_addr,
+	      format_ip6_address, mp->ip4_addr);
+
+  FINISH;
+}
+
+static void
+vl_api_dslite_get_b4_addr_t_handler (vl_api_dslite_get_b4_addr_t * mp)
+{
+  snat_main_t *sm = &snat_main;
+  vl_api_dslite_get_b4_addr_reply_t *rmp;
+  dslite_main_t *dm = &dslite_main;
+  int rv = 0;
+
+  /* *INDENT-OFF* */
+  REPLY_MACRO2 (VL_API_DSLITE_GET_AFTR_ADDR_REPLY,
+  ({
+    memcpy (rmp->ip4_addr, &dm->b4_ip4_addr.as_u8, 4);
+    memcpy (rmp->ip6_addr, &dm->b4_ip6_addr.as_u8, 16);
+  }))
+  /* *INDENT-ON* */
+}
+
+static void *
+vl_api_dslite_get_b4_addr_t_print (vl_api_dslite_get_b4_addr_t * mp,
+				   void *handle)
+{
+  u8 *s;
+
+  s = format (0, "SCRIPT: dslite_get_b4_addr");
+
+  FINISH;
+}
+
+static void
   vl_api_dslite_add_del_pool_addr_range_t_handler
   (vl_api_dslite_add_del_pool_addr_range_t * mp)
 {
@@ -2507,7 +2601,10 @@ _(NAT64_ADD_DEL_PREFIX, nat64_add_del_prefix)                           \
 _(NAT64_PREFIX_DUMP, nat64_prefix_dump)                                 \
 _(NAT64_ADD_DEL_INTERFACE_ADDR, nat64_add_del_interface_addr)           \
 _(DSLITE_ADD_DEL_POOL_ADDR_RANGE, dslite_add_del_pool_addr_range)       \
-_(DSLITE_SET_AFTR_ADDR, dslite_set_aftr_addr)
+_(DSLITE_SET_AFTR_ADDR, dslite_set_aftr_addr)                           \
+_(DSLITE_GET_AFTR_ADDR, dslite_get_aftr_addr)                           \
+_(DSLITE_SET_B4_ADDR, dslite_set_b4_addr)                               \
+_(DSLITE_GET_B4_ADDR, dslite_get_b4_addr)
 
 /* Set up the API message handling tables */
 static clib_error_t *