NAT64: Add NAT64 support for snat plugin (VPP-699)

Basic NAT64 feature (no hairpinning, no multi-thread).

Change-Id: I392fccbce93e70c117f4a9a7ec7cf08d6c537f2d
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 375 insertions, 0 deletions

diff --git a/src/plugins/snat/nat64_in2out.c b/src/plugins/snat/nat64_in2out.c
new file mode 100644
index 00000000000..d9d94a975d1
--- /dev/null
+++ b/src/plugins/snat/nat64_in2out.c
@@ -0,0 +1,375 @@
+/*
+ * Copyright (c) 2017 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.
+ */
+/**
+ * @file
+ * @brief NAT64 IPv6 to IPv4 translation (inside to outside network)
+ */
+
+#include <snat/nat64.h>
+#include <vnet/ip/ip6_to_ip4.h>
+#include <vnet/fib/fib_table.h>
+
+typedef struct
+{
+  u32 sw_if_index;
+  u32 next_index;
+} nat64_in2out_trace_t;
+
+static u8 *
+format_nat64_in2out_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 *);
+  nat64_in2out_trace_t *t = va_arg (*args, nat64_in2out_trace_t *);
+
+  s =
+    format (s, "NAT64-in2out: sw_if_index %d, next index %d", t->sw_if_index,
+	    t->next_index);
+
+  return s;
+}
+
+vlib_node_registration_t nat64_in2out_node;
+
+#define foreach_nat64_in2out_error                 \
+_(UNSUPPORTED_PROTOCOL, "unsupported protocol")    \
+_(IN2OUT_PACKETS, "good in2out packets processed") \
+_(NO_TRANSLATION, "no translation")                \
+_(UNKNOWN, "unknown")
+
+typedef enum
+{
+#define _(sym,str) NAT64_IN2OUT_ERROR_##sym,
+  foreach_nat64_in2out_error
+#undef _
+    NAT64_IN2OUT_N_ERROR,
+} nat64_in2out_error_t;
+
+static char *nat64_in2out_error_strings[] = {
+#define _(sym,string) string,
+  foreach_nat64_in2out_error
+#undef _
+};
+
+typedef enum
+{
+  NAT64_IN2OUT_NEXT_LOOKUP,
+  NAT64_IN2OUT_NEXT_DROP,
+  NAT64_IN2OUT_N_NEXT,
+} nat64_in2out_next_t;
+
+typedef struct nat64_in2out_set_ctx_t_
+{
+  vlib_buffer_t *b;
+  vlib_main_t *vm;
+} nat64_in2out_set_ctx_t;
+
+static int
+nat64_in2out_tcp_udp_set_cb (ip6_header_t * ip6, ip4_header_t * ip4,
+			     void *arg)
+{
+  nat64_main_t *nm = &nat64_main;
+  nat64_in2out_set_ctx_t *ctx = arg;
+  nat64_db_bib_entry_t *bibe;
+  nat64_db_st_entry_t *ste;
+  ip46_address_t saddr, daddr;
+  u32 sw_if_index, fib_index;
+  udp_header_t *udp = ip6_next_header (ip6);
+  snat_protocol_t proto = ip_proto_to_snat_proto (ip6->protocol);
+  u16 sport = udp->src_port;
+  u16 dport = udp->dst_port;
+
+  sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
+  fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6, sw_if_index);
+
+  saddr.as_u64[0] = ip6->src_address.as_u64[0];
+  saddr.as_u64[1] = ip6->src_address.as_u64[1];
+  daddr.as_u64[0] = ip6->dst_address.as_u64[0];
+  daddr.as_u64[1] = ip6->dst_address.as_u64[1];
+
+  ste =
+    nat64_db_st_entry_find (&nm->db, &saddr, &daddr, sport, dport, proto,
+			    fib_index, 1);
+
+  if (ste)
+    {
+      bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
+      if (!bibe)
+	return -1;
+    }
+  else
+    {
+      bibe =
+	nat64_db_bib_entry_find (&nm->db, &saddr, sport, proto, fib_index, 1);
+
+      if (!bibe)
+	{
+	  u16 out_port;
+	  ip4_address_t out_addr;
+	  if (nat64_alloc_out_addr_and_port
+	      (fib_index, proto, &out_addr, &out_port))
+	    return -1;
+
+	  bibe =
+	    nat64_db_bib_entry_create (&nm->db, &ip6->src_address, &out_addr,
+				       sport, clib_host_to_net_u16 (out_port),
+				       fib_index, proto, 0);
+	  if (!bibe)
+	    return -1;
+	}
+
+      ste =
+	nat64_db_st_entry_create (&nm->db, bibe, &ip6->dst_address,
+				  &daddr.ip4, dport);
+      if (!ste)
+	return -1;
+    }
+
+  nat64_session_reset_timeout (ste, ctx->vm);
+
+  ip4->src_address.as_u32 = bibe->out_addr.as_u32;
+  udp->src_port = bibe->out_port;
+
+  ip4->dst_address.as_u32 = daddr.ip4.as_u32;
+
+  return 0;
+}
+
+static int
+nat64_in2out_icmp_set_cb (ip6_header_t * ip6, ip4_header_t * ip4, void *arg)
+{
+  nat64_main_t *nm = &nat64_main;
+  nat64_in2out_set_ctx_t *ctx = arg;
+  nat64_db_bib_entry_t *bibe;
+  nat64_db_st_entry_t *ste;
+  ip46_address_t saddr, daddr;
+  u32 sw_if_index, fib_index;
+  icmp46_header_t *icmp = ip6_next_header (ip6);
+
+  sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
+  fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6, sw_if_index);
+
+  saddr.as_u64[0] = ip6->src_address.as_u64[0];
+  saddr.as_u64[1] = ip6->src_address.as_u64[1];
+  daddr.as_u64[0] = ip6->dst_address.as_u64[0];
+  daddr.as_u64[1] = ip6->dst_address.as_u64[1];
+
+  if (icmp->type == ICMP4_echo_request || icmp->type == ICMP4_echo_reply)
+    {
+      u16 in_id = ((u16 *) (icmp))[2];
+      ste =
+	nat64_db_st_entry_find (&nm->db, &saddr, &daddr, in_id, 0,
+				SNAT_PROTOCOL_ICMP, fib_index, 1);
+
+      if (ste)
+	{
+	  bibe =
+	    nat64_db_bib_entry_by_index (&nm->db, SNAT_PROTOCOL_ICMP,
+					 ste->bibe_index);
+	  if (!bibe)
+	    return -1;
+	}
+      else
+	{
+	  bibe =
+	    nat64_db_bib_entry_find (&nm->db, &saddr, in_id,
+				     SNAT_PROTOCOL_ICMP, fib_index, 1);
+
+	  if (!bibe)
+	    {
+	      u16 out_id;
+	      ip4_address_t out_addr;
+	      if (nat64_alloc_out_addr_and_port
+		  (fib_index, SNAT_PROTOCOL_ICMP, &out_addr, &out_id))
+		return -1;
+
+	      bibe =
+		nat64_db_bib_entry_create (&nm->db, &ip6->src_address,
+					   &out_addr, in_id,
+					   clib_host_to_net_u16 (out_id),
+					   fib_index, SNAT_PROTOCOL_ICMP, 0);
+	      if (!bibe)
+		return -1;
+	    }
+	  ste =
+	    nat64_db_st_entry_create (&nm->db, bibe, &ip6->dst_address,
+				      &daddr.ip4, 0);
+	  if (!ste)
+	    return -1;
+	}
+
+      nat64_session_reset_timeout (ste, ctx->vm);
+
+      ip4->src_address.as_u32 = bibe->out_addr.as_u32;
+      ((u16 *) (icmp))[2] = bibe->out_port;
+
+      ip4->dst_address.as_u32 = daddr.ip4.as_u32;
+    }
+  else
+    {
+      //TODO: ICMP error
+      clib_warning ("not ICMP echo request/reply, %u", icmp->type);
+      return -1;
+    }
+
+  return 0;
+}
+
+static int
+nat64_in2out_inner_icmp_set_cb (ip6_header_t * ip6, ip4_header_t * ip4,
+				void *ctx)
+{
+  //TODO:
+  return -1;
+}
+
+static uword
+nat64_in2out_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
+		      vlib_frame_t * frame)
+{
+  u32 n_left_from, *from, *to_next;
+  nat64_in2out_next_t next_index;
+  u32 pkts_processed = 0;
+
+  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;
+	  ip6_header_t *ip60;
+	  u16 l4_offset0, frag_offset0;
+	  u8 l4_protocol0;
+	  u32 proto0;
+	  nat64_in2out_set_ctx_t ctx0;
+
+	  /* 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);
+
+	  ctx0.b = b0;
+	  ctx0.vm = vm;
+
+	  next0 = NAT64_IN2OUT_NEXT_LOOKUP;
+
+	  if (PREDICT_FALSE
+	      (ip6_parse
+	       (ip60, b0->current_length, &l4_protocol0, &l4_offset0,
+		&frag_offset0)))
+	    {
+	      next0 = NAT64_IN2OUT_NEXT_DROP;
+	      b0->error = node->errors[NAT64_IN2OUT_ERROR_UNKNOWN];
+	      goto trace0;
+	    }
+
+	  proto0 = ip_proto_to_snat_proto (l4_protocol0);
+	  if (PREDICT_FALSE ((proto0 == ~0) || (frag_offset0 != 0)))
+	    {
+	      next0 = NAT64_IN2OUT_NEXT_DROP;
+	      b0->error =
+		node->errors[NAT64_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
+	      goto trace0;
+	    }
+
+	  if (proto0 == SNAT_PROTOCOL_ICMP)
+	    {
+	      if (icmp6_to_icmp
+		  (b0, nat64_in2out_icmp_set_cb, &ctx0,
+		   nat64_in2out_inner_icmp_set_cb, &ctx0))
+		{
+		  next0 = NAT64_IN2OUT_NEXT_DROP;
+		  b0->error = node->errors[NAT64_IN2OUT_ERROR_NO_TRANSLATION];
+		  goto trace0;
+		}
+	    }
+	  else
+	    {
+	      if (ip6_to_ip4_tcp_udp
+		  (b0, nat64_in2out_tcp_udp_set_cb, &ctx0, 0))
+		{
+		  next0 = NAT64_IN2OUT_NEXT_DROP;
+		  b0->error = node->errors[NAT64_IN2OUT_ERROR_NO_TRANSLATION];
+		  goto trace0;
+		}
+	    }
+
+	trace0:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      nat64_in2out_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+	      t->next_index = next0;
+	    }
+
+	  pkts_processed += next0 != NAT64_IN2OUT_NEXT_DROP;
+
+	  /* 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, nat64_in2out_node.index,
+			       NAT64_IN2OUT_ERROR_IN2OUT_PACKETS,
+			       pkts_processed);
+  return frame->n_vectors;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat64_in2out_node) = {
+  .function = nat64_in2out_node_fn,.name = "nat64-in2out",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat64_in2out_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (nat64_in2out_error_strings),
+  .error_strings = nat64_in2out_error_strings,
+  .n_next_nodes = 2,
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [NAT64_IN2OUT_NEXT_DROP] = "error-drop",
+    [NAT64_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat64_in2out_node, nat64_in2out_node_fn);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */