SNAT: IP fragmentation (VPP-890)

Translation of fragmented packets.

Change-Id: I9b1f2e9433ce273638080f32c2d3bff39c49899d
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 395 insertions, 14 deletions

diff --git a/src/plugins/nat/nat64_out2in.c b/src/plugins/nat/nat64_out2in.c
index 61e88a7f304..eb5ecb4588d 100644
--- a/src/plugins/nat/nat64_out2in.c
+++ b/src/plugins/nat/nat64_out2in.c
@@ -18,6 +18,7 @@
  */
 
 #include <nat/nat64.h>
+#include <nat/nat_reass.h>
 #include <vnet/ip/ip4_to_ip6.h>
 #include <vnet/fib/ip4_fib.h>
 
@@ -41,13 +42,41 @@ format_nat64_out2in_trace (u8 * s, va_list * args)
   return s;
 }
 
+typedef struct
+{
+  u32 sw_if_index;
+  u32 next_index;
+  u8 cached;
+} nat64_out2in_reass_trace_t;
+
+static u8 *
+format_nat64_out2in_reass_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_out2in_reass_trace_t *t =
+    va_arg (*args, nat64_out2in_reass_trace_t *);
+
+  s =
+    format (s, "NAT64-out2in-reass: sw_if_index %d, next index %d, status %s",
+	    t->sw_if_index, t->next_index,
+	    t->cached ? "cached" : "translated");
+
+  return s;
+}
+
 vlib_node_registration_t nat64_out2in_node;
+vlib_node_registration_t nat64_out2in_reass_node;
+
+#define foreach_nat64_out2in_error                       \
+_(UNSUPPORTED_PROTOCOL, "Unsupported protocol")          \
+_(OUT2IN_PACKETS, "Good out2in packets processed")       \
+_(NO_TRANSLATION, "No translation")                      \
+_(UNKNOWN, "unknown")                                    \
+_(DROP_FRAGMENT, "Drop fragment")                        \
+_(MAX_REASS, "Maximum reassemblies exceeded")            \
+_(MAX_FRAG, "Maximum fragments per reassembly exceeded")
 
-#define foreach_nat64_out2in_error                 \
-_(UNSUPPORTED_PROTOCOL, "Unsupported protocol")    \
-_(OUT2IN_PACKETS, "Good out2in packets processed") \
-_(NO_TRANSLATION, "No translation")                \
-_(UNKNOWN, "unknown")
 
 typedef enum
 {
@@ -67,6 +96,7 @@ typedef enum
 {
   NAT64_OUT2IN_NEXT_LOOKUP,
   NAT64_OUT2IN_NEXT_DROP,
+  NAT64_OUT2IN_NEXT_REASS,
   NAT64_OUT2IN_N_NEXT,
 } nat64_out2in_next_t;
 
@@ -412,20 +442,27 @@ nat64_out2in_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 
 	  proto0 = ip_proto_to_snat_proto (ip40->protocol);
 
-	  if (proto0 == SNAT_PROTOCOL_ICMP)
+	  if (PREDICT_FALSE (proto0 == ~0))
 	    {
-	      if (icmp_to_icmp6
-		  (b0, nat64_out2in_icmp_set_cb, &ctx0,
-		   nat64_out2in_inner_icmp_set_cb, &ctx0))
+	      if (ip4_to_ip6 (b0, nat64_out2in_unk_proto_set_cb, &ctx0))
 		{
 		  next0 = NAT64_OUT2IN_NEXT_DROP;
 		  b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
-		  goto trace0;
 		}
+	      goto trace0;
 	    }
-	  else if (proto0 == SNAT_PROTOCOL_TCP || proto0 == SNAT_PROTOCOL_UDP)
+
+	  if (PREDICT_FALSE (ip4_is_fragment (ip40)))
 	    {
-	      if (ip4_to_ip6_tcp_udp (b0, nat64_out2in_tcp_udp_set_cb, &ctx0))
+	      next0 = NAT64_OUT2IN_NEXT_REASS;
+	      goto trace0;
+	    }
+
+	  if (proto0 == SNAT_PROTOCOL_ICMP)
+	    {
+	      if (icmp_to_icmp6
+		  (b0, nat64_out2in_icmp_set_cb, &ctx0,
+		   nat64_out2in_inner_icmp_set_cb, &ctx0))
 		{
 		  next0 = NAT64_OUT2IN_NEXT_DROP;
 		  b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
@@ -434,7 +471,7 @@ nat64_out2in_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 	    }
 	  else
 	    {
-	      if (ip4_to_ip6 (b0, nat64_out2in_unk_proto_set_cb, &ctx0))
+	      if (ip4_to_ip6_tcp_udp (b0, nat64_out2in_tcp_udp_set_cb, &ctx0))
 		{
 		  next0 = NAT64_OUT2IN_NEXT_DROP;
 		  b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
@@ -474,17 +511,361 @@ VLIB_REGISTER_NODE (nat64_out2in_node) = {
   .format_trace = format_nat64_out2in_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
   .n_errors = ARRAY_LEN (nat64_out2in_error_strings),
-  .error_strings = nat64_out2in_error_strings,.n_next_nodes = 2,
+  .error_strings = nat64_out2in_error_strings,
+  .n_next_nodes = NAT64_OUT2IN_N_NEXT,
   /* edit / add dispositions here */
   .next_nodes = {
     [NAT64_OUT2IN_NEXT_DROP] = "error-drop",
     [NAT64_OUT2IN_NEXT_LOOKUP] = "ip6-lookup",
+    [NAT64_OUT2IN_NEXT_REASS] = "nat64-out2in-reass",
   },
 };
 /* *INDENT-ON* */
 
 VLIB_NODE_FUNCTION_MULTIARCH (nat64_out2in_node, nat64_out2in_node_fn);
 
+typedef struct nat64_out2in_frag_set_ctx_t_
+{
+  vlib_main_t *vm;
+  vlib_buffer_t *b;
+  u32 sess_index;
+  u8 proto;
+  u8 first_frag;
+} nat64_out2in_frag_set_ctx_t;
+
+static int
+nat64_out2in_frag_set_cb (ip4_header_t * ip4, ip6_header_t * ip6, void *arg)
+{
+  nat64_main_t *nm = &nat64_main;
+  nat64_out2in_frag_set_ctx_t *ctx = arg;
+  nat64_db_st_entry_t *ste;
+  nat64_db_bib_entry_t *bibe;
+  udp_header_t *udp = ip4_next_header (ip4);
+  ip_csum_t csum;
+  u16 *checksum;
+
+  ste = nat64_db_st_entry_by_index (&nm->db, ctx->proto, ctx->sess_index);
+  if (!ste)
+    return -1;
+
+  bibe = nat64_db_bib_entry_by_index (&nm->db, ctx->proto, ste->bibe_index);
+  if (!bibe)
+    return -1;
+
+  nat64_session_reset_timeout (ste, ctx->vm);
+
+  if (ctx->first_frag)
+    {
+      udp->dst_port = bibe->in_port;
+
+      if (ip4->protocol == IP_PROTOCOL_UDP)
+	{
+	  checksum = &udp->checksum;
+
+	  if (!checksum)
+	    {
+	      u16 udp_len =
+		clib_host_to_net_u16 (ip4->length) - sizeof (*ip4);
+	      csum = ip_incremental_checksum (0, udp, udp_len);
+	      csum =
+		ip_csum_with_carry (csum, clib_host_to_net_u16 (udp_len));
+	      csum =
+		ip_csum_with_carry (csum,
+				    clib_host_to_net_u16 (IP_PROTOCOL_UDP));
+	      csum = ip_csum_with_carry (csum, ste->in_r_addr.as_u64[0]);
+	      csum = ip_csum_with_carry (csum, ste->in_r_addr.as_u64[1]);
+	      csum = ip_csum_with_carry (csum, bibe->in_addr.as_u64[0]);
+	      csum = ip_csum_with_carry (csum, bibe->in_addr.as_u64[1]);
+	      *checksum = ~ip_csum_fold (csum);
+	    }
+	  else
+	    {
+	      csum = ip_csum_sub_even (*checksum, bibe->out_addr.as_u32);
+	      csum = ip_csum_sub_even (csum, ste->out_r_addr.as_u32);
+	      csum = ip_csum_sub_even (csum, bibe->out_port);
+	      csum = ip_csum_add_even (csum, ste->in_r_addr.as_u64[0]);
+	      csum = ip_csum_add_even (csum, ste->in_r_addr.as_u64[1]);
+	      csum = ip_csum_add_even (csum, bibe->in_addr.as_u64[0]);
+	      csum = ip_csum_add_even (csum, bibe->in_addr.as_u64[1]);
+	      csum = ip_csum_add_even (csum, bibe->in_port);
+	      *checksum = ip_csum_fold (csum);
+	    }
+	}
+      else
+	{
+	  tcp_header_t *tcp = ip4_next_header (ip4);
+	  checksum = &tcp->checksum;
+	  csum = ip_csum_sub_even (*checksum, bibe->out_addr.as_u32);
+	  csum = ip_csum_sub_even (csum, ste->out_r_addr.as_u32);
+	  csum = ip_csum_sub_even (csum, bibe->out_port);
+	  csum = ip_csum_add_even (csum, ste->in_r_addr.as_u64[0]);
+	  csum = ip_csum_add_even (csum, ste->in_r_addr.as_u64[1]);
+	  csum = ip_csum_add_even (csum, bibe->in_addr.as_u64[0]);
+	  csum = ip_csum_add_even (csum, bibe->in_addr.as_u64[1]);
+	  csum = ip_csum_add_even (csum, bibe->in_port);
+	  *checksum = ip_csum_fold (csum);
+	}
+
+    }
+
+  ip6->src_address.as_u64[0] = ste->in_r_addr.as_u64[0];
+  ip6->src_address.as_u64[1] = ste->in_r_addr.as_u64[1];
+
+  ip6->dst_address.as_u64[0] = bibe->in_addr.as_u64[0];
+  ip6->dst_address.as_u64[1] = bibe->in_addr.as_u64[1];
+
+  vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
+
+  return 0;
+}
+
+static uword
+nat64_out2in_reass_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
+			    vlib_frame_t * frame)
+{
+  u32 n_left_from, *from, *to_next;
+  nat64_out2in_next_t next_index;
+  u32 pkts_processed = 0;
+  u32 *fragments_to_drop = 0;
+  u32 *fragments_to_loopback = 0;
+  nat64_main_t *nm = &nat64_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;
+	  ip4_header_t *ip40;
+	  u8 cached0 = 0;
+	  u32 sw_if_index0, fib_index0;
+	  udp_header_t *udp0;
+	  nat_reass_ip4_t *reass0;
+	  ip46_address_t saddr0, daddr0;
+	  nat64_db_st_entry_t *ste0;
+	  nat64_db_bib_entry_t *bibe0;
+	  ip6_address_t ip6_saddr0;
+	  nat64_out2in_frag_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);
+	  next0 = NAT64_OUT2IN_NEXT_LOOKUP;
+
+	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+	  fib_index0 =
+	    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
+						 sw_if_index0);
+
+	  if (PREDICT_FALSE (nat_reass_is_drop_frag (1)))
+	    {
+	      next0 = NAT64_OUT2IN_NEXT_DROP;
+	      b0->error = node->errors[NAT64_OUT2IN_ERROR_DROP_FRAGMENT];
+	      goto trace0;
+	    }
+
+	  ip40 = vlib_buffer_get_current (b0);
+
+	  if (PREDICT_FALSE (!(ip40->protocol == IP_PROTOCOL_TCP
+			       || ip40->protocol == IP_PROTOCOL_UDP)))
+	    {
+	      next0 = NAT64_OUT2IN_NEXT_DROP;
+	      b0->error = node->errors[NAT64_OUT2IN_ERROR_DROP_FRAGMENT];
+	      goto trace0;
+	    }
+
+	  udp0 = ip4_next_header (ip40);
+
+	  reass0 = nat_ip4_reass_find_or_create (ip40->src_address,
+						 ip40->dst_address,
+						 ip40->fragment_id,
+						 ip40->protocol,
+						 1, &fragments_to_drop);
+
+	  if (PREDICT_FALSE (!reass0))
+	    {
+	      next0 = NAT64_OUT2IN_NEXT_DROP;
+	      b0->error = node->errors[NAT64_OUT2IN_ERROR_MAX_REASS];
+	      goto trace0;
+	    }
+
+	  if (PREDICT_FALSE (ip4_is_first_fragment (ip40)))
+	    {
+	      ctx0.first_frag = 1;
+
+	      memset (&saddr0, 0, sizeof (saddr0));
+	      saddr0.ip4.as_u32 = ip40->src_address.as_u32;
+	      memset (&daddr0, 0, sizeof (daddr0));
+	      daddr0.ip4.as_u32 = ip40->dst_address.as_u32;
+
+	      ste0 =
+		nat64_db_st_entry_find (&nm->db, &daddr0, &saddr0,
+					udp0->dst_port, udp0->src_port,
+					ip40->protocol, fib_index0, 0);
+	      if (!ste0)
+		{
+		  bibe0 =
+		    nat64_db_bib_entry_find (&nm->db, &daddr0, udp0->dst_port,
+					     ip40->protocol, fib_index0, 0);
+		  if (!bibe0)
+		    {
+		      next0 = NAT64_OUT2IN_NEXT_DROP;
+		      b0->error =
+			node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
+		      goto trace0;
+		    }
+
+		  nat64_compose_ip6 (&ip6_saddr0, &ip40->src_address,
+				     bibe0->fib_index);
+		  ste0 =
+		    nat64_db_st_entry_create (&nm->db, bibe0, &ip6_saddr0,
+					      &saddr0.ip4, udp0->src_port);
+
+		  if (!ste0)
+		    {
+		      next0 = NAT64_OUT2IN_NEXT_DROP;
+		      b0->error =
+			node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
+		      goto trace0;
+		    }
+		}
+	      reass0->sess_index =
+		nat64_db_st_entry_get_index (&nm->db, ste0);
+
+	      nat_ip4_reass_get_frags (reass0, &fragments_to_loopback);
+	    }
+	  else
+	    {
+	      ctx0.first_frag = 0;
+
+	      if (PREDICT_FALSE (reass0->sess_index == (u32) ~ 0))
+		{
+		  if (nat_ip4_reass_add_fragment (reass0, bi0))
+		    {
+		      b0->error = node->errors[NAT64_OUT2IN_ERROR_MAX_FRAG];
+		      next0 = NAT64_OUT2IN_NEXT_DROP;
+		      goto trace0;
+		    }
+		  cached0 = 1;
+		  goto trace0;
+		}
+	    }
+
+	  ctx0.sess_index = reass0->sess_index;
+	  ctx0.proto = ip40->protocol;
+	  ctx0.vm = vm;
+	  ctx0.b = b0;
+
+	  if (ip4_to_ip6_fragmented (b0, nat64_out2in_frag_set_cb, &ctx0))
+	    {
+	      next0 = NAT64_OUT2IN_NEXT_DROP;
+	      b0->error = node->errors[NAT64_OUT2IN_ERROR_UNKNOWN];
+	      goto trace0;
+	    }
+
+	trace0:
+	  if (PREDICT_FALSE
+	      ((node->flags & VLIB_NODE_FLAG_TRACE)
+	       && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      nat64_out2in_reass_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->cached = cached0;
+	      t->sw_if_index = sw_if_index0;
+	      t->next_index = next0;
+	    }
+
+	  if (cached0)
+	    {
+	      n_left_to_next++;
+	      to_next--;
+	    }
+	  else
+	    {
+	      pkts_processed += next0 != NAT64_OUT2IN_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);
+	    }
+
+	  if (n_left_from == 0 && vec_len (fragments_to_loopback))
+	    {
+	      from = vlib_frame_vector_args (frame);
+	      u32 len = vec_len (fragments_to_loopback);
+	      if (len <= VLIB_FRAME_SIZE)
+		{
+		  clib_memcpy (from, fragments_to_loopback,
+			       sizeof (u32) * len);
+		  n_left_from = len;
+		  vec_reset_length (fragments_to_loopback);
+		}
+	      else
+		{
+		  clib_memcpy (from,
+			       fragments_to_loopback + (len -
+							VLIB_FRAME_SIZE),
+			       sizeof (u32) * VLIB_FRAME_SIZE);
+		  n_left_from = VLIB_FRAME_SIZE;
+		  _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
+		}
+	    }
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  vlib_node_increment_counter (vm, nat64_out2in_reass_node.index,
+			       NAT64_OUT2IN_ERROR_OUT2IN_PACKETS,
+			       pkts_processed);
+
+  nat_send_all_to_node (vm, fragments_to_drop, node,
+			&node->errors[NAT64_OUT2IN_ERROR_DROP_FRAGMENT],
+			NAT64_OUT2IN_NEXT_DROP);
+
+  vec_free (fragments_to_drop);
+  vec_free (fragments_to_loopback);
+  return frame->n_vectors;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat64_out2in_reass_node) = {
+  .function = nat64_out2in_reass_node_fn,
+  .name = "nat64-out2in-reass",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat64_out2in_reass_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (nat64_out2in_error_strings),
+  .error_strings = nat64_out2in_error_strings,
+  .n_next_nodes = NAT64_OUT2IN_N_NEXT,
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [NAT64_OUT2IN_NEXT_DROP] = "error-drop",
+    [NAT64_OUT2IN_NEXT_LOOKUP] = "ip6-lookup",
+    [NAT64_OUT2IN_NEXT_REASS] = "nat64-out2in-reass",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat64_out2in_reass_node,
+			      nat64_out2in_reass_node_fn);
+
 /*
  * fd.io coding-style-patch-verification: ON
  *