classifier-based ACL: refactor + add output ACL

For implementation of MACIP ACLs enhancement (VPP-1088), an outbound
classifier-based ACL would be needed. There was an existing incomplete
code for outbound ACLs, it looked almost exact copy of input ACLs, minus
the various enhancements, trying to sync that code seemed error-prone
and cumbersome to maintain in the longer run.

This change refactors the input+output ACLs processing into a unified
routine (thus any changes will have effect on both), and also adds
the API to set the output interface ACL, with the same format
and semantics as the existing input one (except working on output
ACL of course).

WARNING: IP outbound ACL in L3 mode clobbers the ip.* fields
in the vnet_buffer_opaque_t, since the code is using l2_classify.*
The net_buffer (p0)->ip.save_rewrite_length is rescued into
l2_classify.pad.l2_len, and used to rewind the header in case of
drop, so that ipX_drop prints something sensible.

Change-Id: I62f814f1e3650e504474a3a5359edb8a0a8836ed
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>

1 files changed, 537 insertions, 0 deletions

diff --git a/src/vnet/l2/l2_in_out_acl.c b/src/vnet/l2/l2_in_out_acl.c
new file mode 100644
index 00000000000..6f86a9f66ae
--- /dev/null
+++ b/src/vnet/l2/l2_in_out_acl.c
@@ -0,0 +1,537 @@
+/*
+ * l2_in_out_acl.c : layer 2 input/output acl processing
+ *
+ * Copyright (c) 2013,2018 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 <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+#include <vnet/ethernet/ethernet.h>
+#include <vnet/ethernet/packet.h>
+#include <vnet/ip/ip_packet.h>
+#include <vnet/ip/ip4_packet.h>
+#include <vnet/ip/ip6_packet.h>
+#include <vlib/cli.h>
+#include <vnet/l2/l2_input.h>
+#include <vnet/l2/l2_output.h>
+#include <vnet/l2/feat_bitmap.h>
+
+#include <vppinfra/error.h>
+#include <vppinfra/hash.h>
+#include <vppinfra/cache.h>
+
+#include <vnet/classify/vnet_classify.h>
+#include <vnet/classify/in_out_acl.h>
+
+typedef struct
+{
+
+  /* Next nodes for each feature */
+  u32 feat_next_node_index[IN_OUT_ACL_N_TABLE_GROUPS][32];
+
+  /* convenience variables */
+  vlib_main_t *vlib_main;
+  vnet_main_t *vnet_main;
+} l2_in_out_acl_main_t;
+
+typedef struct
+{
+  u32 sw_if_index;
+  u32 next_index;
+  u32 table_index;
+  u32 offset;
+} l2_in_out_acl_trace_t;
+
+/* packet trace format function */
+static u8 *
+format_l2_in_out_acl_trace (u8 * s, u32 is_output, 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_in_out_acl_trace_t *t = va_arg (*args, l2_in_out_acl_trace_t *);
+
+  s = format (s, "%s: sw_if_index %d, next_index %d, table %d, offset %d",
+	      is_output ? "OUTACL" : "INACL",
+	      t->sw_if_index, t->next_index, t->table_index, t->offset);
+  return s;
+}
+
+static u8 *
+format_l2_inacl_trace (u8 * s, va_list * args)
+{
+  return format_l2_in_out_acl_trace (s, IN_OUT_ACL_INPUT_TABLE_GROUP, args);
+}
+
+static u8 *
+format_l2_outacl_trace (u8 * s, va_list * args)
+{
+  return format_l2_in_out_acl_trace (s, IN_OUT_ACL_OUTPUT_TABLE_GROUP, args);
+}
+
+l2_in_out_acl_main_t l2_in_out_acl_main;
+
+static vlib_node_registration_t l2_inacl_node;
+static vlib_node_registration_t l2_outacl_node;
+
+#define foreach_l2_inacl_error                  \
+_(NONE, "valid input ACL packets")              \
+_(MISS, "input ACL misses")                     \
+_(HIT, "input ACL hits")                        \
+_(CHAIN_HIT, "input ACL hits after chain walk") \
+_(TABLE_MISS, "input ACL table-miss drops")     \
+_(SESSION_DENY, "input ACL session deny drops")
+
+#define foreach_l2_outacl_error                  \
+_(NONE, "valid output ACL packets")              \
+_(MISS, "output ACL misses")                     \
+_(HIT, "output ACL hits")                        \
+_(CHAIN_HIT, "output ACL hits after chain walk") \
+_(TABLE_MISS, "output ACL table-miss drops")     \
+_(SESSION_DENY, "output ACL session deny drops")
+
+
+typedef enum
+{
+#define _(sym,str) L2_INACL_ERROR_##sym,
+  foreach_l2_inacl_error
+#undef _
+    L2_INACL_N_ERROR,
+} l2_inacl_error_t;
+
+static char *l2_inacl_error_strings[] = {
+#define _(sym,string) string,
+  foreach_l2_inacl_error
+#undef _
+};
+
+typedef enum
+{
+#define _(sym,str) L2_OUTACL_ERROR_##sym,
+  foreach_l2_outacl_error
+#undef _
+    L2_OUTACL_N_ERROR,
+} l2_outacl_error_t;
+
+static char *l2_outacl_error_strings[] = {
+#define _(sym,string) string,
+  foreach_l2_outacl_error
+#undef _
+};
+
+
+static inline uword
+l2_in_out_acl_node_fn (vlib_main_t * vm,
+		       vlib_node_runtime_t * node, vlib_frame_t * frame,
+		       int is_output)
+{
+  u32 n_left_from, *from, *to_next;
+  acl_next_index_t next_index;
+  l2_in_out_acl_main_t *msm = &l2_in_out_acl_main;
+  in_out_acl_main_t *am = &in_out_acl_main;
+  vnet_classify_main_t *vcm = am->vnet_classify_main;
+  in_out_acl_table_id_t tid = IN_OUT_ACL_TABLE_L2;
+  f64 now = vlib_time_now (vm);
+  u32 hits = 0;
+  u32 misses = 0;
+  u32 chain_hits = 0;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;	/* number of packets to process */
+  next_index = node->cached_next_index;
+
+  /* First pass: compute hashes */
+  while (n_left_from > 2)
+    {
+      vlib_buffer_t *b0, *b1;
+      u32 bi0, bi1;
+      u8 *h0, *h1;
+      u32 sw_if_index0, sw_if_index1;
+      u32 table_index0, table_index1;
+      vnet_classify_table_t *t0, *t1;
+
+      /* prefetch next iteration */
+      {
+	vlib_buffer_t *p1, *p2;
+
+	p1 = vlib_get_buffer (vm, from[1]);
+	p2 = vlib_get_buffer (vm, from[2]);
+
+	vlib_prefetch_buffer_header (p1, STORE);
+	CLIB_PREFETCH (p1->data, CLIB_CACHE_LINE_BYTES, STORE);
+	vlib_prefetch_buffer_header (p2, STORE);
+	CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
+      }
+
+      bi0 = from[0];
+      b0 = vlib_get_buffer (vm, bi0);
+
+      bi1 = from[1];
+      b1 = vlib_get_buffer (vm, bi1);
+
+      sw_if_index0 =
+	vnet_buffer (b0)->sw_if_index[is_output ? VLIB_TX : VLIB_RX];
+      table_index0 =
+	am->classify_table_index_by_sw_if_index[is_output][tid][sw_if_index0];
+
+      sw_if_index1 =
+	vnet_buffer (b1)->sw_if_index[is_output ? VLIB_TX : VLIB_RX];
+      table_index1 =
+	am->classify_table_index_by_sw_if_index[is_output][tid][sw_if_index1];
+
+      t0 = pool_elt_at_index (vcm->tables, table_index0);
+
+      t1 = pool_elt_at_index (vcm->tables, table_index1);
+
+      if (t0->current_data_flag == CLASSIFY_FLAG_USE_CURR_DATA)
+	h0 = (void *) vlib_buffer_get_current (b0) + t0->current_data_offset;
+      else
+	h0 = b0->data;
+
+      vnet_buffer (b0)->l2_classify.hash =
+	vnet_classify_hash_packet (t0, (u8 *) h0);
+
+      vnet_classify_prefetch_bucket (t0, vnet_buffer (b0)->l2_classify.hash);
+
+      if (t1->current_data_flag == CLASSIFY_FLAG_USE_CURR_DATA)
+	h1 = (void *) vlib_buffer_get_current (b1) + t1->current_data_offset;
+      else
+	h1 = b1->data;
+
+      vnet_buffer (b1)->l2_classify.hash =
+	vnet_classify_hash_packet (t1, (u8 *) h1);
+
+      vnet_classify_prefetch_bucket (t1, vnet_buffer (b1)->l2_classify.hash);
+
+      vnet_buffer (b0)->l2_classify.table_index = table_index0;
+
+      vnet_buffer (b1)->l2_classify.table_index = table_index1;
+
+      from += 2;
+      n_left_from -= 2;
+    }
+
+  while (n_left_from > 0)
+    {
+      vlib_buffer_t *b0;
+      u32 bi0;
+      u8 *h0;
+      u32 sw_if_index0;
+      u32 table_index0;
+      vnet_classify_table_t *t0;
+
+      bi0 = from[0];
+      b0 = vlib_get_buffer (vm, bi0);
+
+      sw_if_index0 =
+	vnet_buffer (b0)->sw_if_index[is_output ? VLIB_TX : VLIB_RX];
+      table_index0 =
+	am->classify_table_index_by_sw_if_index[is_output][tid][sw_if_index0];
+
+      t0 = pool_elt_at_index (vcm->tables, table_index0);
+
+      if (t0->current_data_flag == CLASSIFY_FLAG_USE_CURR_DATA)
+	h0 = (void *) vlib_buffer_get_current (b0) + t0->current_data_offset;
+      else
+	h0 = b0->data;
+
+      vnet_buffer (b0)->l2_classify.hash =
+	vnet_classify_hash_packet (t0, (u8 *) h0);
+
+      vnet_buffer (b0)->l2_classify.table_index = table_index0;
+      vnet_classify_prefetch_bucket (t0, vnet_buffer (b0)->l2_classify.hash);
+
+      from++;
+      n_left_from--;
+    }
+
+  next_index = node->cached_next_index;
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      /* Not enough load/store slots to dual loop... */
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0 = ACL_NEXT_INDEX_DENY;
+	  u32 table_index0;
+	  vnet_classify_table_t *t0;
+	  vnet_classify_entry_t *e0;
+	  u64 hash0;
+	  u8 *h0;
+	  u8 error0;
+
+	  /* Stride 3 seems to work best */
+	  if (PREDICT_TRUE (n_left_from > 3))
+	    {
+	      vlib_buffer_t *p1 = vlib_get_buffer (vm, from[3]);
+	      vnet_classify_table_t *tp1;
+	      u32 table_index1;
+	      u64 phash1;
+
+	      table_index1 = vnet_buffer (p1)->l2_classify.table_index;
+
+	      if (PREDICT_TRUE (table_index1 != ~0))
+		{
+		  tp1 = pool_elt_at_index (vcm->tables, table_index1);
+		  phash1 = vnet_buffer (p1)->l2_classify.hash;
+		  vnet_classify_prefetch_entry (tp1, phash1);
+		}
+	    }
+
+	  /* 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);
+
+	  table_index0 = vnet_buffer (b0)->l2_classify.table_index;
+	  e0 = 0;
+	  t0 = 0;
+
+	  vnet_buffer (b0)->l2_classify.opaque_index = ~0;
+
+	  /* Determine the next node */
+	  next0 =
+	    vnet_l2_feature_next (b0, msm->feat_next_node_index[is_output],
+				  is_output ? L2OUTPUT_FEAT_ACL :
+				  L2INPUT_FEAT_ACL);
+
+	  if (PREDICT_TRUE (table_index0 != ~0))
+	    {
+	      hash0 = vnet_buffer (b0)->l2_classify.hash;
+	      t0 = pool_elt_at_index (vcm->tables, table_index0);
+
+	      if (t0->current_data_flag == CLASSIFY_FLAG_USE_CURR_DATA)
+		h0 =
+		  (void *) vlib_buffer_get_current (b0) +
+		  t0->current_data_offset;
+	      else
+		h0 = b0->data;
+
+	      e0 = vnet_classify_find_entry (t0, (u8 *) h0, hash0, now);
+	      if (e0)
+		{
+		  vnet_buffer (b0)->l2_classify.opaque_index
+		    = e0->opaque_index;
+		  vlib_buffer_advance (b0, e0->advance);
+
+		  next0 = (e0->next_index < ACL_NEXT_INDEX_N_NEXT) ?
+		    e0->next_index : next0;
+
+		  hits++;
+
+		  if (is_output)
+		    error0 = (next0 == ACL_NEXT_INDEX_DENY) ?
+		      L2_OUTACL_ERROR_SESSION_DENY : L2_INACL_ERROR_NONE;
+		  else
+		    error0 = (next0 == ACL_NEXT_INDEX_DENY) ?
+		      L2_OUTACL_ERROR_SESSION_DENY : L2_OUTACL_ERROR_NONE;
+		  b0->error = node->errors[error0];
+		}
+	      else
+		{
+		  while (1)
+		    {
+		      if (PREDICT_TRUE (t0->next_table_index != ~0))
+			t0 = pool_elt_at_index (vcm->tables,
+						t0->next_table_index);
+		      else
+			{
+			  next0 =
+			    (t0->miss_next_index <
+			     ACL_NEXT_INDEX_N_NEXT) ? t0->miss_next_index :
+			    next0;
+
+			  misses++;
+
+			  if (is_output)
+			    error0 = (next0 == ACL_NEXT_INDEX_DENY) ?
+			      L2_OUTACL_ERROR_TABLE_MISS :
+			      L2_OUTACL_ERROR_NONE;
+			  else
+			    error0 = (next0 == ACL_NEXT_INDEX_DENY) ?
+			      L2_INACL_ERROR_TABLE_MISS : L2_INACL_ERROR_NONE;
+			  b0->error = node->errors[error0];
+			  break;
+			}
+
+		      if (t0->current_data_flag ==
+			  CLASSIFY_FLAG_USE_CURR_DATA)
+			h0 =
+			  (void *) vlib_buffer_get_current (b0) +
+			  t0->current_data_offset;
+		      else
+			h0 = b0->data;
+
+		      hash0 = vnet_classify_hash_packet (t0, (u8 *) h0);
+		      e0 = vnet_classify_find_entry
+			(t0, (u8 *) h0, hash0, now);
+		      if (e0)
+			{
+			  vlib_buffer_advance (b0, e0->advance);
+			  next0 = (e0->next_index < ACL_NEXT_INDEX_N_NEXT) ?
+			    e0->next_index : next0;
+			  hits++;
+			  chain_hits++;
+
+			  if (is_output)
+			    error0 = (next0 == ACL_NEXT_INDEX_DENY) ?
+			      L2_OUTACL_ERROR_SESSION_DENY :
+			      L2_OUTACL_ERROR_NONE;
+			  else
+			    error0 = (next0 == ACL_NEXT_INDEX_DENY) ?
+			      L2_INACL_ERROR_SESSION_DENY :
+			      L2_INACL_ERROR_NONE;
+			  b0->error = node->errors[error0];
+			  break;
+			}
+		    }
+		}
+	    }
+
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      l2_in_out_acl_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->sw_if_index =
+		vnet_buffer (b0)->sw_if_index[is_output ? VLIB_TX : VLIB_RX];
+	      t->next_index = next0;
+	      t->table_index = t0 ? t0 - vcm->tables : ~0;
+	      t->offset = (t0 && e0) ? vnet_classify_get_offset (t0, e0) : ~0;
+	    }
+
+	  /* 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,
+			       is_output ? L2_OUTACL_ERROR_MISS :
+			       L2_INACL_ERROR_MISS, misses);
+  vlib_node_increment_counter (vm, node->node_index,
+			       is_output ? L2_OUTACL_ERROR_HIT :
+			       L2_INACL_ERROR_HIT, hits);
+  vlib_node_increment_counter (vm, node->node_index,
+			       is_output ? L2_OUTACL_ERROR_CHAIN_HIT :
+			       L2_INACL_ERROR_CHAIN_HIT, chain_hits);
+  return frame->n_vectors;
+}
+
+static uword
+l2_inacl_node_fn (vlib_main_t * vm,
+		  vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return l2_in_out_acl_node_fn (vm, node, frame,
+				IN_OUT_ACL_INPUT_TABLE_GROUP);
+}
+
+static uword
+l2_outacl_node_fn (vlib_main_t * vm,
+		   vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return l2_in_out_acl_node_fn (vm, node, frame,
+				IN_OUT_ACL_OUTPUT_TABLE_GROUP);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (l2_inacl_node,static) = {
+  .function = l2_inacl_node_fn,
+  .name = "l2-input-acl",
+  .vector_size = sizeof (u32),
+  .format_trace = format_l2_inacl_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(l2_inacl_error_strings),
+  .error_strings = l2_inacl_error_strings,
+
+  .n_next_nodes = ACL_NEXT_INDEX_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+       [ACL_NEXT_INDEX_DENY]  = "error-drop",
+  },
+};
+
+VLIB_REGISTER_NODE (l2_outacl_node,static) = {
+  .function = l2_outacl_node_fn,
+  .name = "l2-output-acl",
+  .vector_size = sizeof (u32),
+  .format_trace = format_l2_outacl_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(l2_outacl_error_strings),
+  .error_strings = l2_outacl_error_strings,
+
+  .n_next_nodes = ACL_NEXT_INDEX_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+       [ACL_NEXT_INDEX_DENY]  = "error-drop",
+  },
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (l2_inacl_node, l2_inacl_node_fn)
+VLIB_NODE_FUNCTION_MULTIARCH (l2_outacl_node, l2_outacl_node_fn)
+/* *INDENT-ON* */
+
+
+clib_error_t *
+l2_in_out_acl_init (vlib_main_t * vm)
+{
+  l2_in_out_acl_main_t *mp = &l2_in_out_acl_main;
+
+  mp->vlib_main = vm;
+  mp->vnet_main = vnet_get_main ();
+
+  /* Initialize the feature next-node indexes */
+  feat_bitmap_init_next_nodes (vm,
+			       l2_inacl_node.index,
+			       L2INPUT_N_FEAT,
+			       l2input_get_feat_names (),
+			       mp->feat_next_node_index
+			       [IN_OUT_ACL_INPUT_TABLE_GROUP]);
+  feat_bitmap_init_next_nodes (vm, l2_outacl_node.index, L2OUTPUT_N_FEAT,
+			       l2output_get_feat_names (),
+			       mp->feat_next_node_index
+			       [IN_OUT_ACL_OUTPUT_TABLE_GROUP]);
+
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (l2_in_out_acl_init);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */