l2-rw: Packet rewrite feature for L2 bridges

This patch defines a new l2input feature: l2-rw
It makes use of vnet_classify in order to match
packets and applies mask/value changes depending
on the matched classify entry.

Change-Id: Ia98c128931e59195bf3ecb66721e155ff9049a2e
Signed-off-by: Pierre Pfister <ppfister@cisco.com>

vnet/Makefile.am

@@ -114,6 +114,7 @@ libvnet_la_SOURCES +=				\
  vnet/l2/l2_output_acl.c			\
  vnet/l2/l2_output.c				\
  vnet/l2/l2_patch.c				\
+ vnet/l2/l2_rw.c                                \
  vnet/l2/l2_vtr.c				\
  vnet/l2/l2_xcrw.c
 
@@ -129,6 +130,7 @@ nobase_include_HEADERS +=			\
  vnet/l2/l2_bvi.h				\
  vnet/l2/l2_flood.h				\
  vnet/l2/l2_fib.h				\
+ vnet/l2/l2_rw.h                                \
  vnet/l2/l2_xcrw.h				\
  vnet/l2/l2_classify.h
 

vnet/vnet/l2/l2_input.c

@@ -507,7 +507,16 @@ u32 l2input_intf_bitmap_enable (u32 sw_if_index,
   return config->feature_bitmap;
 }
 
-
+u32 l2input_set_bridge_features(u32 bd_index,
+                                 u32 feat_mask, u32 feat_value)
+{
+  l2_bridge_domain_t * bd_config;
+  vec_validate (l2input_main.bd_configs, bd_index);
+  bd_config = vec_elt_at_index(l2input_main.bd_configs, bd_index);
+  bd_validate (bd_config);
+  bd_config->feature_bitmap = (bd_config->feature_bitmap & ~feat_mask) | feat_value;
+  return bd_config->feature_bitmap;
+}
 
 // Set the subinterface to run in l2 or l3 mode.
 // for L3 mode, just the sw_if_index is specified

vnet/vnet/l2/l2_input.h

@@ -93,6 +93,7 @@ l2input_bd_config_from_index (l2input_main_t * l2im, u32 bd_index)
  _(ARP_TERM,      "arp-term-l2bd")              \
  _(UU_FLOOD,      "l2-flood")                   \
  _(FWD,           "l2-fwd")                     \
+ _(RW,            "l2-rw")                      \
  _(LEARN,         "l2-learn")                   \
  _(VTR,           "l2-input-vtr")               \
  _(VPATH,         "vpath-input-l2")             \
@@ -196,6 +197,11 @@ u32 l2input_intf_bitmap_enable (u32 sw_if_index,
                                  u32 feature_bitmap,
                                  u32 enable);
 
+//Sets modifies flags from a bridge domain
+u32 l2input_set_bridge_features(u32 bd_index,
+                                u32 feat_mask,
+                                u32 feat_value);
+
 
 #define MODE_L3        0
 #define MODE_L2_BRIDGE 1

vnet/vnet/l2/l2_rw.h

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2015 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.
+ */
+
+/*
+ * l2_rw is based on vnet classifier and provides a way
+ * to modify packets matching a given table.
+ *
+ * Tables must be created using vnet's classify features.
+ * Entries contained within these tables must have their
+ * opaque index set to the rewrite entry created with l2_rw_mod_entry.
+ */
+
+#ifndef L2_RW_H_
+#define L2_RW_H_
+
+#include <vnet/l2/l2_input.h>
+
+typedef CLIB_PACKED(struct _l2_rw_entry {
+  u16 skip_n_vectors;
+  u16 rewrite_n_vectors;
+  u64 hit_count;
+  u32x4 *mask;
+  u32x4 *value;
+}) l2_rw_entry_t;
+
+// l2_rw configuration for one interface
+typedef CLIB_PACKED(struct _l2_rw_config {
+  u32 table_index; //Which classify table to use
+  u32 miss_index;  //Rewrite entry to use if table does not match
+}) l2_rw_config_t;
+
+typedef struct {
+  /* Next feature node indexes */
+  u32 feat_next_node_index[32];
+
+  /* A pool of entries */
+  l2_rw_entry_t *entries;
+
+  /* Config vector indexed by sw_if_index */
+  l2_rw_config_t *configs;
+  uword *configs_bitmap;
+} l2_rw_main_t;
+
+extern l2_rw_main_t l2_rw_main;
+
+/*
+ * Specifies which classify table and miss_index should be used
+ * with the given interface.
+ * Use special values ~0 in order to un-set table_index
+ * or miss_index.
+ * l2_rw feature is automatically enabled for the interface
+ * when table_index or miss_index is not ~0.
+ * returns 0 on success and something else on error.
+ */
+int l2_rw_interface_set_table(u32 sw_if_index,
+                              u32 table_index,
+                              u32 miss_index);
+
+/*
+ * Creates, modifies or delete a rewrite entry.
+ * If *index != ~0, modifies an existing entry (or simply
+ * deletes it if is_del is set).
+ * If *index == ~0, creates a new entry and the created
+ * entry index is stored in *index (Does nothing if is_del
+ * is set).
+ * returns 0 on success and something else on error.
+ */
+int l2_rw_mod_entry(u32 *index,
+                    u8 *mask, u8 *value, u32 len,
+                    u32 skip, u8 is_del);
+
+#endif /* L2_FW_H_ */