gbp_policy.c

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/*
 * 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.
 */

#include <plugins/gbp/gbp.h>
#include <plugins/gbp/gbp_policy_dpo.h>

#include <vnet/vxlan-gbp/vxlan_gbp_packet.h>

/**
 * Grouping of global data for the GBP source EPG classification feature
 */
typedef struct gbp_policy_main_t_
{
  /**
   * Next nodes for L2 output features
   */
  u32 l2_output_feat_next[2][32];
} gbp_policy_main_t;

static gbp_policy_main_t gbp_policy_main;

#define foreach_gbp_policy                      \
  _(DENY,    "deny")

typedef enum
{
#define _(sym,str) GBP_ERROR_##sym,
  foreach_gbp_policy
#undef _
    GBP_POLICY_N_ERROR,
} gbp_policy_error_t;

static char *gbp_policy_error_strings[] = {
#define _(sym,string) string,
  foreach_gbp_policy
#undef _
};

typedef enum
{
#define _(sym,str) GBP_POLICY_NEXT_##sym,
  foreach_gbp_policy
#undef _
    GBP_POLICY_N_NEXT,
} gbp_policy_next_t;

/**
 * per-packet trace data
 */
typedef struct gbp_policy_trace_t_
{
  /* per-pkt trace data */
  u32 src_epg;
  u32 dst_epg;
  u32 acl_index;
  u32 allowed;
} gbp_policy_trace_t;

always_inline dpo_proto_t
ethertype_to_dpo_proto (u16 etype)
{
  etype = clib_net_to_host_u16 (etype);

  switch (etype)
    {
    case ETHERNET_TYPE_IP4:
      return (DPO_PROTO_IP4);
    case ETHERNET_TYPE_IP6:
      return (DPO_PROTO_IP6);
    }

  return (DPO_PROTO_NONE);
}

always_inline u32
gbp_rule_l2_redirect (const gbp_rule_t * gu, vlib_buffer_t * b0)
{
  const ethernet_header_t *eth0;
  const dpo_id_t *dpo;
  dpo_proto_t dproto;

  eth0 = vlib_buffer_get_current (b0);
  /* pop the ethernet header to prepare for L3 rewrite */
  vlib_buffer_advance (b0, vnet_buffer (b0)->l2.l2_len);

  dproto = ethertype_to_dpo_proto (eth0->type);
  dpo = &gu->gu_dpo[GBP_POLICY_NODE_L2][dproto];

  /* save the LB index for the next node and reset the IP flow hash
   * so it's recalculated */
  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = dpo->dpoi_index;
  vnet_buffer (b0)->ip.flow_hash = 0;

  return (dpo->dpoi_next_node);
}

always_inline u8
gbp_policy_is_ethertype_allowed (const gbp_contract_t * gc0, u16 ethertype)
{
  u16 *et;

  vec_foreach (et, gc0->gc_allowed_ethertypes)
  {
    if (*et == ethertype)
      return (1);
  }
  return (0);
}

static uword
gbp_policy_inline (vlib_main_t * vm,
                   vlib_node_runtime_t * node,
                   vlib_frame_t * frame, u8 is_port_based)
{
  gbp_main_t *gm = &gbp_main;
  gbp_policy_main_t *gpm = &gbp_policy_main;
  u32 n_left_from, *from, *to_next;
  u32 next_index;

  next_index = 0;
  n_left_from = frame->n_vectors;
  from = vlib_frame_vector_args (frame);

  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)
        {
          const ethernet_header_t *h0;
          const gbp_endpoint_t *ge0;
          const gbp_contract_t *gc0;
          gbp_policy_next_t next0;
          gbp_contract_key_t key0;
          u32 bi0, sw_if_index0;
          vlib_buffer_t *b0;
          index_t gci0;

          gc0 = NULL;
          next0 = GBP_POLICY_NEXT_DENY;
          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);
          h0 = vlib_buffer_get_current (b0);
          sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_TX];

          /*
           * If the A0bit is set then policy has already been applied
           * and we skip enforcement here.
           */
          if (vnet_buffer2 (b0)->gbp.flags & VXLAN_GBP_GPFLAGS_A)
            {
              next0 = vnet_l2_feature_next (b0,
                                            gpm->l2_output_feat_next
                                            [is_port_based],
                                            (is_port_based ?
                                             L2OUTPUT_FEAT_GBP_POLICY_PORT :
                                             L2OUTPUT_FEAT_GBP_POLICY_MAC));
              key0.as_u32 = ~0;
              goto trace;
            }
          /*
           * determine the src and dst EPG
           */
          if (is_port_based)
            ge0 = gbp_endpoint_find_itf (sw_if_index0);
          else
            ge0 = gbp_endpoint_find_mac (h0->dst_address,
                                         vnet_buffer (b0)->l2.bd_index);

          if (NULL != ge0)
            key0.gck_dst = ge0->ge_fwd.gef_epg_id;
          else
            /* If you cannot determine the destination EP then drop */
            goto trace;

          key0.gck_src = vnet_buffer2 (b0)->gbp.src_epg;

          if (EPG_INVALID != key0.gck_src)
            {
              if (PREDICT_FALSE (key0.gck_src == key0.gck_dst))
                {
                  /*
                   * intra-epg allowed
                   */
                  next0 =
                    vnet_l2_feature_next (b0,
                                          gpm->l2_output_feat_next
                                          [is_port_based],
                                          (is_port_based ?
                                           L2OUTPUT_FEAT_GBP_POLICY_PORT :
                                           L2OUTPUT_FEAT_GBP_POLICY_MAC));
                  vnet_buffer2 (b0)->gbp.flags |= VXLAN_GBP_GPFLAGS_A;
                }
              else
                {
                  gci0 = gbp_contract_find (&key0);

                  if (INDEX_INVALID != gci0)
                    {
                      u32 rule_match_p0, trace_bitmap0;
                      fa_5tuple_opaque_t pkt_5tuple0;
                      u32 acl_pos_p0, acl_match_p0;
                      u8 is_ip60, l2_len0, action0;
                      const gbp_rule_t *gu;
                      u16 ether_type0;
                      const u8 *h0;

                      action0 = 0;
                      gc0 = gbp_contract_get (gci0);
                      l2_len0 = vnet_buffer (b0)->l2.l2_len;
                      h0 = vlib_buffer_get_current (b0);

                      ether_type0 = *(u16 *) (h0 + l2_len0 - 2);

                      if (!gbp_policy_is_ethertype_allowed (gc0, ether_type0))
                        {
                          /*
                           * black list model so drop
                           */
                          goto trace;
                        }

                      if ((ether_type0 ==
                           clib_net_to_host_u16 (ETHERNET_TYPE_IP6))
                          || (ether_type0 ==
                              clib_net_to_host_u16 (ETHERNET_TYPE_IP4)))
                        {
                          is_ip60 =
                            (ether_type0 ==
                             clib_net_to_host_u16 (ETHERNET_TYPE_IP6)) ? 1 :
                            0;
                          /*
                           * tests against the ACL
                           */
                          acl_plugin_fill_5tuple_inline (gm->
                                                         acl_plugin.p_acl_main,
                                                         gc0->gc_lc_index, b0,
                                                         is_ip60,
                                                         /* is_input */ 0,
                                                         /* is_l2_path */ 1,
                                                         &pkt_5tuple0);
                          acl_plugin_match_5tuple_inline (gm->
                                                          acl_plugin.p_acl_main,
                                                          gc0->gc_lc_index,
                                                          &pkt_5tuple0,
                                                          is_ip60, &action0,
                                                          &acl_pos_p0,
                                                          &acl_match_p0,
                                                          &rule_match_p0,
                                                          &trace_bitmap0);

                          if (action0 > 0)
                            {
                              vnet_buffer2 (b0)->gbp.flags |=
                                VXLAN_GBP_GPFLAGS_A;
                              gu =
                                gbp_rule_get (gc0->gc_rules[rule_match_p0]);

                              switch (gu->gu_action)
                                {
                                case GBP_RULE_PERMIT:
                                  next0 = vnet_l2_feature_next
                                    (b0,
                                     gpm->l2_output_feat_next
                                     [is_port_based],
                                     (is_port_based ?
                                      L2OUTPUT_FEAT_GBP_POLICY_PORT :
                                      L2OUTPUT_FEAT_GBP_POLICY_MAC));
                                  break;
                                case GBP_RULE_DENY:
                                  ASSERT (0);
                                  next0 = 0;
                                  break;
                                case GBP_RULE_REDIRECT:
                                  next0 = gbp_rule_l2_redirect (gu, b0);
                                  break;
                                }
                            }
                        }
                    }
                }
            }
          else
            {
              /*
               * the src EPG is not set when the packet arrives on an EPG
               * uplink interface and we do not need to apply policy
               */
              next0 =
                vnet_l2_feature_next (b0,
                                      gpm->l2_output_feat_next[is_port_based],
                                      (is_port_based ?
                                       L2OUTPUT_FEAT_GBP_POLICY_PORT :
                                       L2OUTPUT_FEAT_GBP_POLICY_MAC));
            }

        trace:
          if (PREDICT_FALSE ((b0->flags & VLIB_BUFFER_IS_TRACED)))
            {
              gbp_policy_trace_t *t =
                vlib_add_trace (vm, node, b0, sizeof (*t));
              t->src_epg = key0.gck_src;
              t->dst_epg = key0.gck_dst;
              t->acl_index = (gc0 ? gc0->gc_acl_index : ~0),
                t->allowed = (next0 != GBP_POLICY_NEXT_DENY);
            }

          /* 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);
    }

  return frame->n_vectors;
}

static uword
gbp_policy_port (vlib_main_t * vm,
                 vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  return (gbp_policy_inline (vm, node, frame, 1));
}

static uword
gbp_policy_mac (vlib_main_t * vm,
                vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  return (gbp_policy_inline (vm, node, frame, 0));
}

/* packet trace format function */
static u8 *
format_gbp_policy_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 *);
  gbp_policy_trace_t *t = va_arg (*args, gbp_policy_trace_t *);

  s =
    format (s, "src:%d, dst:%d, acl:%d allowed:%d",
            t->src_epg, t->dst_epg, t->acl_index, t->allowed);

  return s;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (gbp_policy_port_node) = {
  .function = gbp_policy_port,
  .name = "gbp-policy-port",
  .vector_size = sizeof (u32),
  .format_trace = format_gbp_policy_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = ARRAY_LEN(gbp_policy_error_strings),
  .error_strings = gbp_policy_error_strings,

  .n_next_nodes = GBP_POLICY_N_NEXT,

  .next_nodes = {
    [GBP_POLICY_NEXT_DENY] = "error-drop",
  },
};

VLIB_NODE_FUNCTION_MULTIARCH (gbp_policy_port_node, gbp_policy_port);

VLIB_REGISTER_NODE (gbp_policy_mac_node) = {
  .function = gbp_policy_mac,
  .name = "gbp-policy-mac",
  .vector_size = sizeof (u32),
  .format_trace = format_gbp_policy_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .sibling_of = "gbp-policy-port",
};

VLIB_NODE_FUNCTION_MULTIARCH (gbp_policy_mac_node, gbp_policy_mac);

/* *INDENT-ON* */

static clib_error_t *
gbp_policy_init (vlib_main_t * vm)
{
  gbp_policy_main_t *gpm = &gbp_policy_main;
  clib_error_t *error = 0;

  /* Initialize the feature next-node indexes */
  feat_bitmap_init_next_nodes (vm,
                               gbp_policy_port_node.index,
                               L2OUTPUT_N_FEAT,
                               l2output_get_feat_names (),
                               gpm->l2_output_feat_next[1]);
  feat_bitmap_init_next_nodes (vm,
                               gbp_policy_mac_node.index,
                               L2OUTPUT_N_FEAT,
                               l2output_get_feat_names (),
                               gpm->l2_output_feat_next[0]);

  return error;
}

VLIB_INIT_FUNCTION (gbp_policy_init);

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */