NAT: Refactoring / Housekeeping (VPP-1415)

Change-Id: Ia3ce24cc94f9b2fb331ad62a4181ddcd41bc78ca
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 516 insertions, 0 deletions

diff --git a/src/plugins/nat/nat44_classify.c b/src/plugins/nat/nat44_classify.c
new file mode 100644
index 00000000000..0e9863c02ac
--- /dev/null
+++ b/src/plugins/nat/nat44_classify.c
@@ -0,0 +1,516 @@
+/*
+ * 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.
+ */
+/**
+ * @file
+ * @brief Classify for one armed NAT44 (in+out interface)
+ */
+
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/fib/ip4_fib.h>
+#include <nat/nat.h>
+#include <nat/nat_reass.h>
+#include <nat/nat_inlines.h>
+
+vlib_node_registration_t nat44_classify_node;
+vlib_node_registration_t nat44_ed_classify_node;
+vlib_node_registration_t nat44_det_classify_node;
+vlib_node_registration_t nat44_handoff_classify_node;
+
+#define foreach_nat44_classify_error                      \
+_(MAX_REASS, "Maximum reassemblies exceeded")             \
+_(MAX_FRAG, "Maximum fragments per reassembly exceeded")
+
+typedef enum
+{
+#define _(sym,str) NAT44_CLASSIFY_ERROR_##sym,
+  foreach_nat44_classify_error
+#undef _
+    NAT44_CLASSIFY_N_ERROR,
+} nat44_classify_error_t;
+
+static char *nat44_classify_error_strings[] = {
+#define _(sym,string) string,
+  foreach_nat44_classify_error
+#undef _
+};
+
+typedef enum
+{
+  NAT44_CLASSIFY_NEXT_IN2OUT,
+  NAT44_CLASSIFY_NEXT_OUT2IN,
+  NAT44_CLASSIFY_NEXT_DROP,
+  NAT44_CLASSIFY_N_NEXT,
+} nat44_classify_next_t;
+
+typedef struct
+{
+  u8 next_in2out;
+  u8 cached;
+} nat44_classify_trace_t;
+
+static u8 *
+format_nat44_classify_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 *);
+  nat44_classify_trace_t *t = va_arg (*args, nat44_classify_trace_t *);
+  char *next;
+
+  if (t->cached)
+    s = format (s, "nat44-classify: fragment cached");
+  else
+    {
+      next = t->next_in2out ? "nat44-in2out" : "nat44-out2in";
+      s = format (s, "nat44-classify: next %s", next);
+    }
+
+  return s;
+}
+
+static inline uword
+nat44_classify_node_fn_inline (vlib_main_t * vm,
+			       vlib_node_runtime_t * node,
+			       vlib_frame_t * frame, int is_ed)
+{
+  u32 n_left_from, *from, *to_next;
+  nat44_classify_next_t next_index;
+  snat_main_t *sm = &snat_main;
+  snat_static_mapping_t *m;
+  u32 thread_index = vm->thread_index;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  u32 *fragments_to_drop = 0;
+  u32 *fragments_to_loopback = 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 = NAT44_CLASSIFY_NEXT_IN2OUT, sw_if_index0, rx_fib_index0;
+	  ip4_header_t *ip0;
+	  snat_address_t *ap;
+	  snat_session_key_t m_key0;
+	  clib_bihash_kv_8_8_t kv0, value0;
+	  clib_bihash_kv_16_8_t ed_kv0, ed_value0;
+	  udp_header_t *udp0;
+	  nat_reass_ip4_t *reass0;
+	  u8 cached0 = 0;
+
+	  /* 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);
+	  ip0 = vlib_buffer_get_current (b0);
+	  udp0 = ip4_next_header (ip0);
+
+	  if (is_ed && ip0->protocol != IP_PROTOCOL_ICMP)
+	    {
+	      if (!ip4_is_fragment (ip0) || ip4_is_first_fragment (ip0))
+		{
+		  /* process leading fragment/whole packet (with L4 header) */
+		  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+		  rx_fib_index0 =
+		    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
+							 sw_if_index0);
+		  make_ed_kv (&ed_kv0, &ip0->src_address, &ip0->dst_address,
+			      ip0->protocol, rx_fib_index0, udp0->src_port,
+			      udp0->dst_port);
+		  if (ip4_is_fragment (ip0))
+		    {
+		      reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
+							     ip0->dst_address,
+							     ip0->fragment_id,
+							     ip0->protocol,
+							     1,
+							     &fragments_to_drop);
+		      if (PREDICT_FALSE (!reass0))
+			{
+			  next0 = NAT44_CLASSIFY_NEXT_DROP;
+			  b0->error =
+			    node->errors[NAT44_CLASSIFY_ERROR_MAX_REASS];
+			  nat_log_notice ("maximum reassemblies exceeded");
+			  goto enqueue0;
+			}
+		      if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &ed_kv0,
+						    &ed_value0))
+			{
+			  /* session exists so classify as IN2OUT,
+			   * save this information for future fragments and set
+			   * past fragments to be looped over and reprocessed */
+			  reass0->sess_index = ed_value0.value;
+			  reass0->classify_next =
+			    NAT_REASS_IP4_CLASSIFY_NEXT_IN2OUT;
+			  nat_ip4_reass_get_frags (reass0,
+						   &fragments_to_loopback);
+			  goto enqueue0;
+			}
+		      else
+			{
+			  /* session doesn't exist so continue in the code,
+			   * save this information for future fragments and set
+			   * past fragments to be looped over and reprocessed */
+			  reass0->flags |=
+			    NAT_REASS_FLAG_CLASSIFY_ED_CONTINUE;
+			  nat_ip4_reass_get_frags (reass0,
+						   &fragments_to_loopback);
+			}
+		    }
+		  else
+		    {
+		      /* process whole packet */
+		      if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &ed_kv0,
+						    &ed_value0))
+			goto enqueue0;
+		      /* session doesn't exist so continue in code */
+		    }
+		}
+	      else
+		{
+		  /* process non-first fragment */
+		  reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
+							 ip0->dst_address,
+							 ip0->fragment_id,
+							 ip0->protocol,
+							 1,
+							 &fragments_to_drop);
+		  if (PREDICT_FALSE (!reass0))
+		    {
+		      next0 = NAT44_CLASSIFY_NEXT_DROP;
+		      b0->error =
+			node->errors[NAT44_CLASSIFY_ERROR_MAX_REASS];
+		      nat_log_notice ("maximum reassemblies exceeded");
+		      goto enqueue0;
+		    }
+		  /* check if first fragment has arrived */
+		  if (reass0->classify_next == NAT_REASS_IP4_CLASSIFY_NONE &&
+		      !(reass0->flags & NAT_REASS_FLAG_CLASSIFY_ED_CONTINUE))
+		    {
+		      /* first fragment still hasn't arrived, cache this fragment */
+		      if (nat_ip4_reass_add_fragment (reass0, bi0,
+						      &fragments_to_drop))
+			{
+			  b0->error =
+			    node->errors[NAT44_CLASSIFY_ERROR_MAX_FRAG];
+			  nat_log_notice
+			    ("maximum fragments per reassembly exceeded");
+			  next0 = NAT44_CLASSIFY_NEXT_DROP;
+			  goto enqueue0;
+			}
+		      cached0 = 1;
+		      goto enqueue0;
+		    }
+		  if (reass0->classify_next ==
+		      NAT_REASS_IP4_CLASSIFY_NEXT_IN2OUT)
+		    goto enqueue0;
+		  /* flag NAT_REASS_FLAG_CLASSIFY_ED_CONTINUE is set
+		   * so keep the default next0 and continue in code to
+		   * potentially find other classification for this packet */
+		}
+	    }
+
+          /* *INDENT-OFF* */
+          vec_foreach (ap, sm->addresses)
+            {
+              if (ip0->dst_address.as_u32 == ap->addr.as_u32)
+                {
+                  next0 = NAT44_CLASSIFY_NEXT_OUT2IN;
+                  goto enqueue0;
+                }
+            }
+          /* *INDENT-ON* */
+
+	  if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
+	    {
+	      m_key0.addr = ip0->dst_address;
+	      m_key0.port = 0;
+	      m_key0.protocol = 0;
+	      m_key0.fib_index = 0;
+	      kv0.key = m_key0.as_u64;
+	      /* try to classify the fragment based on IP header alone */
+	      if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external,
+					   &kv0, &value0))
+		{
+		  m = pool_elt_at_index (sm->static_mappings, value0.value);
+		  if (m->local_addr.as_u32 != m->external_addr.as_u32)
+		    next0 = NAT44_CLASSIFY_NEXT_OUT2IN;
+		  goto enqueue0;
+		}
+	      if (!ip4_is_fragment (ip0) || ip4_is_first_fragment (ip0))
+		{
+		  /* process leading fragment/whole packet (with L4 header) */
+		  m_key0.port = clib_net_to_host_u16 (udp0->dst_port);
+		  m_key0.protocol = ip_proto_to_snat_proto (ip0->protocol);
+		  kv0.key = m_key0.as_u64;
+		  if (!clib_bihash_search_8_8
+		      (&sm->static_mapping_by_external, &kv0, &value0))
+		    {
+		      m =
+			pool_elt_at_index (sm->static_mappings, value0.value);
+		      if (m->local_addr.as_u32 != m->external_addr.as_u32)
+			next0 = NAT44_CLASSIFY_NEXT_OUT2IN;
+		    }
+		  if (ip4_is_fragment (ip0))
+		    {
+		      reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
+							     ip0->dst_address,
+							     ip0->fragment_id,
+							     ip0->protocol,
+							     1,
+							     &fragments_to_drop);
+		      if (PREDICT_FALSE (!reass0))
+			{
+			  next0 = NAT44_CLASSIFY_NEXT_DROP;
+			  b0->error =
+			    node->errors[NAT44_CLASSIFY_ERROR_MAX_REASS];
+			  nat_log_notice ("maximum reassemblies exceeded");
+			  goto enqueue0;
+			}
+		      /* save classification for future fragments and set past
+		       * fragments to be looped over and reprocessed */
+		      if (next0 == NAT44_CLASSIFY_NEXT_OUT2IN)
+			reass0->classify_next =
+			  NAT_REASS_IP4_CLASSIFY_NEXT_OUT2IN;
+		      else
+			reass0->classify_next =
+			  NAT_REASS_IP4_CLASSIFY_NEXT_IN2OUT;
+		      nat_ip4_reass_get_frags (reass0,
+					       &fragments_to_loopback);
+		    }
+		}
+	      else
+		{
+		  /* process non-first fragment */
+		  reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
+							 ip0->dst_address,
+							 ip0->fragment_id,
+							 ip0->protocol,
+							 1,
+							 &fragments_to_drop);
+		  if (PREDICT_FALSE (!reass0))
+		    {
+		      next0 = NAT44_CLASSIFY_NEXT_DROP;
+		      b0->error =
+			node->errors[NAT44_CLASSIFY_ERROR_MAX_REASS];
+		      nat_log_notice ("maximum reassemblies exceeded");
+		      goto enqueue0;
+		    }
+		  if (reass0->classify_next == NAT_REASS_IP4_CLASSIFY_NONE)
+		    /* first fragment still hasn't arrived */
+		    {
+		      if (nat_ip4_reass_add_fragment (reass0, bi0,
+						      &fragments_to_drop))
+			{
+			  b0->error =
+			    node->errors[NAT44_CLASSIFY_ERROR_MAX_FRAG];
+			  nat_log_notice
+			    ("maximum fragments per reassembly exceeded");
+			  next0 = NAT44_CLASSIFY_NEXT_DROP;
+			  goto enqueue0;
+			}
+		      cached0 = 1;
+		      goto enqueue0;
+		    }
+		  else if (reass0->classify_next ==
+			   NAT_REASS_IP4_CLASSIFY_NEXT_OUT2IN)
+		    next0 = NAT44_CLASSIFY_NEXT_OUT2IN;
+		  else if (reass0->classify_next ==
+			   NAT_REASS_IP4_CLASSIFY_NEXT_IN2OUT)
+		    next0 = NAT44_CLASSIFY_NEXT_IN2OUT;
+		}
+	    }
+
+	enqueue0:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      nat44_classify_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->cached = cached0;
+	      if (!cached0)
+		t->next_in2out = next0 == NAT44_CLASSIFY_NEXT_IN2OUT ? 1 : 0;
+	    }
+
+	  if (cached0)
+	    {
+	      n_left_to_next++;
+	      to_next--;
+	    }
+	  else
+	    /* 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);
+    }
+
+  nat_send_all_to_node (vm, fragments_to_drop, node, 0,
+			NAT44_CLASSIFY_NEXT_DROP);
+
+  vec_free (fragments_to_drop);
+
+  return frame->n_vectors;
+}
+
+static uword
+nat44_classify_node_fn (vlib_main_t * vm,
+			vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return nat44_classify_node_fn_inline (vm, node, frame, 0);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_classify_node) = {
+  .function = nat44_classify_node_fn,
+  .name = "nat44-classify",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat44_classify_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN(nat44_classify_error_strings),
+  .error_strings = nat44_classify_error_strings,
+  .n_next_nodes = NAT44_CLASSIFY_N_NEXT,
+  .next_nodes = {
+    [NAT44_CLASSIFY_NEXT_IN2OUT] = "nat44-in2out",
+    [NAT44_CLASSIFY_NEXT_OUT2IN] = "nat44-out2in",
+    [NAT44_CLASSIFY_NEXT_DROP] = "error-drop",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_classify_node, nat44_classify_node_fn);
+static uword
+nat44_ed_classify_node_fn (vlib_main_t * vm,
+			   vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return nat44_classify_node_fn_inline (vm, node, frame, 1);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_ed_classify_node) = {
+  .function = nat44_ed_classify_node_fn,
+  .name = "nat44-ed-classify",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat44_classify_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_next_nodes = NAT44_CLASSIFY_N_NEXT,
+  .next_nodes = {
+    [NAT44_CLASSIFY_NEXT_IN2OUT] = "nat44-ed-in2out",
+    [NAT44_CLASSIFY_NEXT_OUT2IN] = "nat44-ed-out2in",
+    [NAT44_CLASSIFY_NEXT_DROP] = "error-drop",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_classify_node,
+			      nat44_ed_classify_node_fn);
+
+static uword
+nat44_det_classify_node_fn (vlib_main_t * vm,
+			    vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return nat44_classify_node_fn_inline (vm, node, frame, 0);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_det_classify_node) = {
+  .function = nat44_det_classify_node_fn,
+  .name = "nat44-det-classify",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat44_classify_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_next_nodes = NAT44_CLASSIFY_N_NEXT,
+  .next_nodes = {
+    [NAT44_CLASSIFY_NEXT_IN2OUT] = "nat44-det-in2out",
+    [NAT44_CLASSIFY_NEXT_OUT2IN] = "nat44-det-out2in",
+    [NAT44_CLASSIFY_NEXT_DROP] = "error-drop",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_det_classify_node,
+			      nat44_det_classify_node_fn);
+
+static uword
+nat44_handoff_classify_node_fn (vlib_main_t * vm,
+				vlib_node_runtime_t * node,
+				vlib_frame_t * frame)
+{
+  return nat44_classify_node_fn_inline (vm, node, frame, 0);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_handoff_classify_node) = {
+  .function = nat44_handoff_classify_node_fn,
+  .name = "nat44-handoff-classify",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat44_classify_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_next_nodes = NAT44_CLASSIFY_N_NEXT,
+  .next_nodes = {
+    [NAT44_CLASSIFY_NEXT_IN2OUT] = "nat44-in2out-worker-handoff",
+    [NAT44_CLASSIFY_NEXT_OUT2IN] = "nat44-out2in-worker-handoff",
+    [NAT44_CLASSIFY_NEXT_DROP] = "error-drop",
+  },
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_handoff_classify_node,
+                              nat44_handoff_classify_node_fn);
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */