node.c

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/*
 * 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.
 */
#include <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vppinfra/error.h>
#include <srv6-ad/ad.h>


/******************************* Packet tracing *******************************/

typedef struct
{
  u32 localsid_index;
} srv6_ad_localsid_trace_t;

typedef struct
{
  u8 error;
  ip6_address_t src, dst;
} srv6_ad_rewrite_trace_t;

static u8 *
format_srv6_ad_localsid_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 *);
  srv6_ad_localsid_trace_t *t = va_arg (*args, srv6_ad_localsid_trace_t *);

  return format (s, "SRv6-AD-localsid: localsid_index %d", t->localsid_index);
}

static u8 *
format_srv6_ad_rewrite_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 *);
  srv6_ad_rewrite_trace_t *t = va_arg (*args, srv6_ad_rewrite_trace_t *);

  if (PREDICT_FALSE (t->error != 0))
    {
      return format (s, "SRv6-AD-rewrite: cache is empty");
    }

  return format (s, "SRv6-AD-rewrite: src %U dst %U",
                 format_ip6_address, &t->src, format_ip6_address, &t->dst);
}


/***************************** Nodes registration *****************************/

vlib_node_registration_t srv6_ad4_rewrite_node;
vlib_node_registration_t srv6_ad6_rewrite_node;


/****************************** Packet counters *******************************/

#define foreach_srv6_ad_rewrite_counter \
_(PROCESSED, "srv6-ad rewritten packets") \
_(NO_RW, "(Error) No header for rewriting.")

typedef enum
{
#define _(sym,str) SRV6_AD_REWRITE_COUNTER_##sym,
  foreach_srv6_ad_rewrite_counter
#undef _
    SRV6_AD_REWRITE_N_COUNTERS,
} srv6_ad_rewrite_counters;

static char *srv6_ad_rewrite_counter_strings[] = {
#define _(sym,string) string,
  foreach_srv6_ad_rewrite_counter
#undef _
};


/********************************* Next nodes *********************************/

typedef enum
{
  SRV6_AD_LOCALSID_NEXT_ERROR,
  SRV6_AD_LOCALSID_NEXT_REWRITE4,
  SRV6_AD_LOCALSID_NEXT_REWRITE6,
  SRV6_AD_LOCALSID_N_NEXT,
} srv6_ad_localsid_next_t;

typedef enum
{
  SRV6_AD_REWRITE_NEXT_ERROR,
  SRV6_AD_REWRITE_NEXT_LOOKUP,
  SRV6_AD_REWRITE_N_NEXT,
} srv6_ad_rewrite_next_t;


/******************************* Local SID node *******************************/

/**
 * @brief Function doing SRH processing for AD behavior
 */
static_always_inline void
end_ad_processing (vlib_buffer_t * b0,
                   ip6_header_t * ip0,
                   ip6_sr_header_t * sr0,
                   ip6_sr_localsid_t * ls0, u32 * next0)
{
  ip6_address_t *new_dst0;
  u16 total_size;
  ip6_ext_header_t *next_ext_header;
  u8 next_hdr;
  srv6_ad_localsid_t *ls0_mem;

  if (PREDICT_FALSE (ip0->protocol != IP_PROTOCOL_IPV6_ROUTE ||
                     sr0->type != ROUTING_HEADER_TYPE_SR))
    {
      return;
    }

  if (PREDICT_FALSE (sr0->segments_left == 0))
    {
      return;
    }

  /* Decrement Segments Left and update Destination Address */
  sr0->segments_left -= 1;
  new_dst0 = (ip6_address_t *) (sr0->segments) + sr0->segments_left;
  ip0->dst_address.as_u64[0] = new_dst0->as_u64[0];
  ip0->dst_address.as_u64[1] = new_dst0->as_u64[1];

  /* Compute the total size of the IPv6 header and extensions */
  total_size = sizeof (ip6_header_t);
  next_ext_header = (ip6_ext_header_t *) (ip0 + 1);
  next_hdr = ip0->protocol;

  while (ip6_ext_hdr (next_hdr))
    {
      total_size += ip6_ext_header_len (next_ext_header);
      next_hdr = next_ext_header->next_hdr;
      next_ext_header = ip6_ext_next_header (next_ext_header);
    }

  /* Make sure next header is IP */
  if (PREDICT_FALSE
      (next_hdr != IP_PROTOCOL_IPV6 && next_hdr != IP_PROTOCOL_IP_IN_IP))
    {
      return;
    }

  /* Retrieve SID memory */
  ls0_mem = ls0->plugin_mem;

  /* Cache IP header and extensions */
  if (PREDICT_FALSE (total_size > ls0_mem->rw_len))
    {
      vec_validate (ls0_mem->rewrite, total_size - 1);
    }
  clib_memcpy (ls0_mem->rewrite, ip0, total_size);
  ls0_mem->rw_len = total_size;

  /* Remove IP header and extensions */
  vlib_buffer_advance (b0, total_size);

  /* Set Xconnect adjacency to VNF */
  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = ls0_mem->nh_adj;

  if (ls0_mem->ip_version == DA_IP4)
    *next0 = SRV6_AD_LOCALSID_NEXT_REWRITE4;
  else if (ls0_mem->ip_version == DA_IP6)
    *next0 = SRV6_AD_LOCALSID_NEXT_REWRITE6;
}

/**
 * @brief SRv6 AD Localsid graph node
 */
static uword
srv6_ad_localsid_fn (vlib_main_t * vm,
                     vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  ip6_sr_main_t *sm = &sr_main;
  u32 n_left_from, next_index, *from, *to_next;
  u32 cnt_packets = 0;

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

  u32 thread_index = vm->thread_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);

      /* TODO: Dual/quad loop */

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t *b0;
          ip6_header_t *ip0 = 0;
          ip6_sr_header_t *sr0;
          ip6_sr_localsid_t *ls0;
          u32 next0 = SRV6_AD_LOCALSID_NEXT_ERROR;

          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);
          sr0 = (ip6_sr_header_t *) (ip0 + 1);

          /* Lookup the SR End behavior based on IP DA (adj) */
          ls0 = pool_elt_at_index (sm->localsids,
                                   vnet_buffer (b0)->ip.adj_index[VLIB_TX]);

          /* SRH processing */
          end_ad_processing (b0, ip0, sr0, ls0, &next0);

          if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
            {
              srv6_ad_localsid_trace_t *tr =
                vlib_add_trace (vm, node, b0, sizeof *tr);
              tr->localsid_index = ls0 - sm->localsids;
            }

          /* This increments the SRv6 per LocalSID counters. */
          vlib_increment_combined_counter (((next0 ==
                                             SRV6_AD_LOCALSID_NEXT_ERROR) ?
                                            &(sm->sr_ls_invalid_counters) :
                                            &(sm->sr_ls_valid_counters)),
                                           thread_index, ls0 - sm->localsids,
                                           1, vlib_buffer_length_in_chain (vm,
                                                                           b0));

          vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
                                           n_left_to_next, bi0, next0);

          cnt_packets++;
        }

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  return frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (srv6_ad_localsid_node) = {
  .function = srv6_ad_localsid_fn,
  .name = "srv6-ad-localsid",
  .vector_size = sizeof (u32),
  .format_trace = format_srv6_ad_localsid_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_next_nodes = SRV6_AD_LOCALSID_N_NEXT,
  .next_nodes = {
    [SRV6_AD_LOCALSID_NEXT_REWRITE4] = "ip4-rewrite",
    [SRV6_AD_LOCALSID_NEXT_REWRITE6] = "ip6-rewrite",
    [SRV6_AD_LOCALSID_NEXT_ERROR] = "error-drop",
  },
};
/* *INDENT-ON* */


/******************************* Rewriting node *******************************/

/**
 * @brief Graph node for applying a SR policy into an IPv6 packet. Encapsulation
 */
static uword
srv6_ad4_rewrite_fn (vlib_main_t * vm,
                     vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  ip6_sr_main_t *srm = &sr_main;
  srv6_ad_main_t *sm = &srv6_ad_main;
  u32 n_left_from, next_index, *from, *to_next;
  u32 cnt_packets = 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);

      /* TODO: Dual/quad loop */

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t *b0;
          ip4_header_t *ip0_encap = 0;
          ip6_header_t *ip0 = 0;
          ip6_sr_localsid_t *ls0;
          srv6_ad_localsid_t *ls0_mem;
          u32 next0 = SRV6_AD_REWRITE_NEXT_LOOKUP;
          u16 new_l0 = 0;

          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_encap = vlib_buffer_get_current (b0);
          ls0 = pool_elt_at_index (srm->localsids,
                                   sm->sw_iface_localsid4[vnet_buffer
                                                          (b0)->sw_if_index
                                                          [VLIB_RX]]);
          ls0_mem = ls0->plugin_mem;

          if (PREDICT_FALSE (ls0_mem == NULL || ls0_mem->rewrite == NULL))
            {
              next0 = SRV6_AD_REWRITE_NEXT_ERROR;
              b0->error = node->errors[SRV6_AD_REWRITE_COUNTER_NO_RW];
            }
          else
            {
              ASSERT (VLIB_BUFFER_PRE_DATA_SIZE >=
                      (ls0_mem->rw_len + b0->current_data));

              clib_memcpy (((u8 *) ip0_encap) - ls0_mem->rw_len,
                           ls0_mem->rewrite, ls0_mem->rw_len);
              vlib_buffer_advance (b0, -(word) ls0_mem->rw_len);

              ip0 = vlib_buffer_get_current (b0);

              /* Update inner IPv4 TTL and checksum */
              u32 checksum0;
              ip0_encap->ttl -= 1;
              checksum0 = ip0_encap->checksum + clib_host_to_net_u16 (0x0100);
              checksum0 += checksum0 >= 0xffff;
              ip0_encap->checksum = checksum0;

              /* Update outer IPv6 length (in case it has changed) */
              new_l0 = ls0_mem->rw_len - sizeof (ip6_header_t) +
                clib_net_to_host_u16 (ip0_encap->length);
              ip0->payload_length = clib_host_to_net_u16 (new_l0);
            }

          if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE) &&
              PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
            {
              srv6_ad_rewrite_trace_t *tr =
                vlib_add_trace (vm, node, b0, sizeof *tr);
              tr->error = 0;

              if (next0 == SRV6_AD_REWRITE_NEXT_ERROR)
                {
                  tr->error = 1;
                }
              else
                {
                  clib_memcpy (tr->src.as_u8, ip0->src_address.as_u8,
                               sizeof tr->src.as_u8);
                  clib_memcpy (tr->dst.as_u8, ip0->dst_address.as_u8,
                               sizeof tr->dst.as_u8);
                }
            }

          vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
                                           n_left_to_next, bi0, next0);

          cnt_packets++;
        }

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  /* Update counters */
  vlib_node_increment_counter (vm, srv6_ad4_rewrite_node.index,
                               SRV6_AD_REWRITE_COUNTER_PROCESSED,
                               cnt_packets);

  return frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (srv6_ad4_rewrite_node) = {
  .function = srv6_ad4_rewrite_fn,
  .name = "srv6-ad4-rewrite",
  .vector_size = sizeof (u32),
  .format_trace = format_srv6_ad_rewrite_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = SRV6_AD_REWRITE_N_COUNTERS,
  .error_strings = srv6_ad_rewrite_counter_strings,
  .n_next_nodes = SRV6_AD_REWRITE_N_NEXT,
  .next_nodes = {
      [SRV6_AD_REWRITE_NEXT_LOOKUP] = "ip6-lookup",
      [SRV6_AD_REWRITE_NEXT_ERROR] = "error-drop",
  },
};
/* *INDENT-ON* */


/**
 * @brief Graph node for applying a SR policy into an IPv6 packet. Encapsulation
 */
static uword
srv6_ad6_rewrite_fn (vlib_main_t * vm,
                     vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  ip6_sr_main_t *srm = &sr_main;
  srv6_ad_main_t *sm = &srv6_ad_main;
  u32 n_left_from, next_index, *from, *to_next;
  u32 cnt_packets = 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);

      /* TODO: Dual/quad loop */

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t *b0;
          ip6_header_t *ip0 = 0, *ip0_encap = 0;
          ip6_sr_localsid_t *ls0;
          srv6_ad_localsid_t *ls0_mem;
          u32 next0 = SRV6_AD_REWRITE_NEXT_LOOKUP;
          u16 new_l0 = 0;

          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_encap = vlib_buffer_get_current (b0);
          ls0 = pool_elt_at_index (srm->localsids,
                                   sm->sw_iface_localsid6[vnet_buffer
                                                          (b0)->sw_if_index
                                                          [VLIB_RX]]);
          ls0_mem = ls0->plugin_mem;

          if (PREDICT_FALSE (ls0_mem == NULL || ls0_mem->rewrite == NULL))
            {
              next0 = SRV6_AD_REWRITE_NEXT_ERROR;
              b0->error = node->errors[SRV6_AD_REWRITE_COUNTER_NO_RW];
            }
          else
            {
              ASSERT (VLIB_BUFFER_PRE_DATA_SIZE >=
                      (ls0_mem->rw_len + b0->current_data));

              clib_memcpy (((u8 *) ip0_encap) - ls0_mem->rw_len,
                           ls0_mem->rewrite, ls0_mem->rw_len);
              vlib_buffer_advance (b0, -(word) ls0_mem->rw_len);

              ip0 = vlib_buffer_get_current (b0);

              /* Update inner IPv6 hop limit */
              ip0_encap->hop_limit -= 1;

              /* Update outer IPv6 length (in case it has changed) */
              new_l0 = ls0_mem->rw_len +
                clib_net_to_host_u16 (ip0_encap->payload_length);
              ip0->payload_length = clib_host_to_net_u16 (new_l0);
            }

          if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE) &&
              PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
            {
              srv6_ad_rewrite_trace_t *tr =
                vlib_add_trace (vm, node, b0, sizeof *tr);
              tr->error = 0;

              if (next0 == SRV6_AD_REWRITE_NEXT_ERROR)
                {
                  tr->error = 1;
                }
              else
                {
                  clib_memcpy (tr->src.as_u8, ip0->src_address.as_u8,
                               sizeof tr->src.as_u8);
                  clib_memcpy (tr->dst.as_u8, ip0->dst_address.as_u8,
                               sizeof tr->dst.as_u8);
                }
            }

          vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
                                           n_left_to_next, bi0, next0);

          cnt_packets++;
        }

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  /* Update counters */
  vlib_node_increment_counter (vm, srv6_ad6_rewrite_node.index,
                               SRV6_AD_REWRITE_COUNTER_PROCESSED,
                               cnt_packets);

  return frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (srv6_ad6_rewrite_node) = {
  .function = srv6_ad6_rewrite_fn,
  .name = "srv6-ad6-rewrite",
  .vector_size = sizeof (u32),
  .format_trace = format_srv6_ad_rewrite_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = SRV6_AD_REWRITE_N_COUNTERS,
  .error_strings = srv6_ad_rewrite_counter_strings,
  .n_next_nodes = SRV6_AD_REWRITE_N_NEXT,
  .next_nodes = {
      [SRV6_AD_REWRITE_NEXT_LOOKUP] = "ip6-lookup",
      [SRV6_AD_REWRITE_NEXT_ERROR] = "error-drop",
  },
};
/* *INDENT-ON* */

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