ipsec_if_in.c

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/*
 * ipsec_if_in.c : IPSec interface input node
 *
 * 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 <vnet/vnet.h>
#include <vnet/api_errno.h>
#include <vnet/ip/ip.h>

#include <vnet/ipsec/ipsec.h>
#include <vnet/ipsec/esp.h>
#include <vnet/ipsec/ipsec_io.h>
#include <vnet/ipsec/ipsec_punt.h>

/* Statistics (not really errors) */
#define foreach_ipsec_if_input_error                              \
_(RX, "good packets received")                                    \
_(DISABLED, "ipsec packets received on disabled interface")       \
_(NO_TUNNEL, "no matching tunnel")                                \
_(NAT_KEEPALIVE, "NAT Keepalive")                                 \
_(TOO_SHORT, "Too Short")                                         \
_(SPI_0, "SPI 0")

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

typedef enum
{
#define _(sym,str) IPSEC_IF_INPUT_ERROR_##sym,
  foreach_ipsec_if_input_error
#undef _
    IPSEC_IF_INPUT_N_ERROR,
} ipsec_if_input_error_t;


typedef struct
{
  union
  {
    ipsec4_tunnel_key_t key4;
    ipsec6_tunnel_key_t key6;
  };
  u8 is_ip6;
  u32 seq;
} ipsec_if_input_trace_t;

static u8 *
format_ipsec_if_input_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 *);
  ipsec_if_input_trace_t *t = va_arg (*args, ipsec_if_input_trace_t *);

  if (t->is_ip6)
    s = format (s, "IPSec: %U seq %u",
                format_ipsec6_tunnel_key, &t->key6, t->seq);
  else
    s = format (s, "IPSec: %U seq %u",
                format_ipsec4_tunnel_key, &t->key4, t->seq);
  return s;
}

always_inline u16
ipsec_ip4_if_no_tunnel (vlib_node_runtime_t * node,
                        vlib_buffer_t * b,
                        const esp_header_t * esp,
                        const ip4_header_t * ip4, u16 offset)
{
  if (PREDICT_FALSE (0 == esp->spi))
    {
      b->error = node->errors[IPSEC_IF_INPUT_ERROR_SPI_0];
      b->punt_reason =
        ipsec_punt_reason[(ip4->protocol == IP_PROTOCOL_UDP ?
                           IPSEC_PUNT_IP4_SPI_UDP_0 :
                           IPSEC_PUNT_IP4_NO_SUCH_TUNNEL)];
    }
  else
    {
      b->error = node->errors[IPSEC_IF_INPUT_ERROR_NO_TUNNEL];
      b->punt_reason = ipsec_punt_reason[IPSEC_PUNT_IP4_NO_SUCH_TUNNEL];
    }
  vlib_buffer_advance (b, -offset);
  return IPSEC_INPUT_NEXT_PUNT;
}

always_inline u16
ipsec_ip6_if_no_tunnel (vlib_node_runtime_t * node,
                        vlib_buffer_t * b,
                        const esp_header_t * esp, u16 offset)
{
  b->error = node->errors[IPSEC_IF_INPUT_ERROR_NO_TUNNEL];
  b->punt_reason = ipsec_punt_reason[IPSEC_PUNT_IP6_NO_SUCH_TUNNEL];

  vlib_buffer_advance (b, -offset);
  return (IPSEC_INPUT_NEXT_PUNT);
}

always_inline uword
ipsec_if_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
                       vlib_frame_t * from_frame, int is_ip6)
{
  ipsec_main_t *im = &ipsec_main;
  vnet_main_t *vnm = im->vnet_main;
  vnet_interface_main_t *vim = &vnm->interface_main;

  int is_trace = node->flags & VLIB_NODE_FLAG_TRACE;
  u32 thread_index = vm->thread_index;

  u32 n_left_from, *from;
  u16 nexts[VLIB_FRAME_SIZE], *next;
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;

  from = vlib_frame_vector_args (from_frame);
  n_left_from = from_frame->n_vectors;

  vlib_get_buffers (vm, from, bufs, n_left_from);
  b = bufs;
  next = nexts;

  clib_memset_u16 (nexts, im->esp4_decrypt_next_index, n_left_from);

  u64 n_bytes = 0, n_packets = 0;
  u32 n_disabled = 0, n_no_tunnel = 0;

  u32 last_sw_if_index = ~0;
  u32 last_tunnel_id = ~0;
  ipsec4_tunnel_key_t last_key4;
  ipsec6_tunnel_key_t last_key6;

  vlib_combined_counter_main_t *rx_counter;
  vlib_combined_counter_main_t *drop_counter;

  if (is_ip6)
    clib_memset (&last_key6, 0xff, sizeof (last_key6));
  else
    last_key4.as_u64 = ~0;

  rx_counter = vim->combined_sw_if_counters + VNET_INTERFACE_COUNTER_RX;
  drop_counter = vim->combined_sw_if_counters + VNET_INTERFACE_COUNTER_DROP;

  while (n_left_from >= 2)
    {
      u32 sw_if_index0, sw_if_index1;
      ip4_header_t *ip40, *ip41;
      ip6_header_t *ip60, *ip61;
      esp_header_t *esp0, *esp1;
      u32 len0, len1;
      u16 buf_adv0, buf_adv1;
      u16 buf_rewind0, buf_rewind1;
      u32 tid0, tid1;
      ipsec_tunnel_if_t *t0, *t1;
      ipsec4_tunnel_key_t key40, key41;
      ipsec6_tunnel_key_t key60, key61;

      if (n_left_from >= 4)
        {
          CLIB_PREFETCH (b[2], CLIB_CACHE_LINE_BYTES, STORE);
          CLIB_PREFETCH (b[2]->data, CLIB_CACHE_LINE_BYTES, LOAD);
          CLIB_PREFETCH (b[3], CLIB_CACHE_LINE_BYTES, STORE);
          CLIB_PREFETCH (b[3]->data, CLIB_CACHE_LINE_BYTES, LOAD);
        }

      ip40 =
        (ip4_header_t *) (b[0]->data + vnet_buffer (b[0])->l3_hdr_offset);
      ip41 =
        (ip4_header_t *) (b[1]->data + vnet_buffer (b[1])->l3_hdr_offset);

      if (is_ip6)
        {
          ip60 = (ip6_header_t *) ip40;
          ip61 = (ip6_header_t *) ip41;
          esp0 = (esp_header_t *) ((u8 *) ip60 + sizeof (ip6_header_t));
          esp1 = (esp_header_t *) ((u8 *) ip61 + sizeof (ip6_header_t));
          buf_adv0 = sizeof (ip6_header_t);
          buf_adv1 = sizeof (ip6_header_t);
        }
      else
        {
          /* NAT UDP port 4500 case, don't advance any more */
          if (ip40->protocol == IP_PROTOCOL_UDP)
            {
              esp0 =
                (esp_header_t *) ((u8 *) ip40 + ip4_header_bytes (ip40) +
                                  sizeof (udp_header_t));
              buf_adv0 = 0;
              buf_rewind0 = ip4_header_bytes (ip40) + sizeof (udp_header_t);
            }
          else
            {
              esp0 = (esp_header_t *) ((u8 *) ip40 + ip4_header_bytes (ip40));
              buf_rewind0 = buf_adv0 = ip4_header_bytes (ip40);
            }
          /* NAT UDP port 4500 case, don't advance any more */
          if (ip41->protocol == IP_PROTOCOL_UDP)
            {
              esp1 =
                (esp_header_t *) ((u8 *) ip41 + ip4_header_bytes (ip41) +
                                  sizeof (udp_header_t));
              buf_adv1 = 0;
              buf_rewind1 = ip4_header_bytes (ip41) + sizeof (udp_header_t);
            }
          else
            {
              esp1 = (esp_header_t *) ((u8 *) ip41 + ip4_header_bytes (ip41));
              buf_rewind1 = buf_adv1 = ip4_header_bytes (ip41);
            }
        }

      vlib_buffer_advance (b[0], buf_adv0);
      vlib_buffer_advance (b[1], buf_adv1);

      len0 = vlib_buffer_length_in_chain (vm, b[0]);
      len1 = vlib_buffer_length_in_chain (vm, b[1]);

      /* If the packet is too short to contain an SPI, then maybe
       * it's a keep alive */
      if (len0 < sizeof (esp_header_t))
        {
          if (esp0->spi_bytes[0] == 0xff)
            b[0]->error = node->errors[IPSEC_IF_INPUT_ERROR_NAT_KEEPALIVE];
          else
            b[0]->error = node->errors[IPSEC_IF_INPUT_ERROR_TOO_SHORT];

          next[0] = IPSEC_INPUT_NEXT_DROP;
          goto pkt1;
        }

      if (is_ip6)
        {
          key60.remote_ip = ip60->src_address;
          key60.spi = esp0->spi;

          if (memcmp (&key60, &last_key6, sizeof (last_key6)) == 0)
            {
              tid0 = last_tunnel_id;
            }
          else
            {
              uword *p =
                hash_get_mem (im->ipsec6_if_pool_index_by_key, &key60);
              if (p)
                {
                  tid0 = p[0];
                  last_tunnel_id = tid0;
                  clib_memcpy_fast (&last_key6, &key60, sizeof (key60));
                }
              else
                {
                  next[0] =
                    ipsec_ip6_if_no_tunnel (node, b[0], esp0, buf_adv0);
                  n_no_tunnel++;
                  goto pkt1;
                }
            }
        }
      else                      /* !is_ip6 */
        {
          key40.remote_ip = ip40->src_address;
          key40.spi = esp0->spi;

          if (key40.as_u64 == last_key4.as_u64)
            {
              tid0 = last_tunnel_id;
            }
          else
            {
              uword *p =
                hash_get (im->ipsec4_if_pool_index_by_key, key40.as_u64);
              if (p)
                {
                  tid0 = p[0];
                  last_tunnel_id = tid0;
                  last_key4.as_u64 = key40.as_u64;
                }
              else
                {
                  next[0] =
                    ipsec_ip4_if_no_tunnel (node, b[0], esp0, ip40,
                                            buf_rewind0);
                  n_no_tunnel++;
                  goto pkt1;
                }
            }
        }

      t0 = pool_elt_at_index (im->tunnel_interfaces, tid0);
      vnet_buffer (b[0])->ipsec.sad_index = t0->input_sa_index;

      if (PREDICT_TRUE (t0->hw_if_index != ~0))
        {
          sw_if_index0 = t0->sw_if_index;
          vnet_buffer (b[0])->sw_if_index[VLIB_RX] = sw_if_index0;

          if (PREDICT_FALSE (!(t0->flags & VNET_HW_INTERFACE_FLAG_LINK_UP)))
            {
              vlib_increment_combined_counter
                (drop_counter, thread_index, sw_if_index0, 1, len0);
              n_disabled++;
              b[0]->error = node->errors[IPSEC_IF_INPUT_ERROR_DISABLED];
              next[0] = IPSEC_INPUT_NEXT_DROP;
              goto pkt1;
            }

          if (PREDICT_TRUE (sw_if_index0 == last_sw_if_index))
            {
              n_packets++;
              n_bytes += len0;
            }
          else
            {
              if (n_packets)
                {
                  vlib_increment_combined_counter
                    (rx_counter, thread_index, last_sw_if_index,
                     n_packets, n_bytes);
                }

              last_sw_if_index = sw_if_index0;
              n_packets = 1;
              n_bytes = len0;
            }
        }

    pkt1:

      if (len1 < sizeof (esp_header_t))
        {
          if (esp0->spi_bytes[0] == 0xff)
            b[1]->error = node->errors[IPSEC_IF_INPUT_ERROR_NAT_KEEPALIVE];
          else
            b[1]->error = node->errors[IPSEC_IF_INPUT_ERROR_TOO_SHORT];

          next[1] = IPSEC_INPUT_NEXT_DROP;
          goto trace1;
        }

      if (is_ip6)
        {
          key61.remote_ip = ip61->src_address;
          key61.spi = esp1->spi;

          if (memcmp (&key61, &last_key6, sizeof (last_key6)) == 0)
            {
              tid1 = last_tunnel_id;
            }
          else
            {
              uword *p =
                hash_get_mem (im->ipsec6_if_pool_index_by_key, &key61);
              if (p)
                {
                  tid1 = p[0];
                  last_tunnel_id = tid1;
                  clib_memcpy_fast (&last_key6, &key61, sizeof (key61));
                }
              else
                {
                  next[1] =
                    ipsec_ip6_if_no_tunnel (node, b[1], esp1, buf_adv1);
                  n_no_tunnel++;
                  goto trace1;
                }
            }
        }
      else                      /* !is_ip6 */
        {
          key41.remote_ip = ip41->src_address;
          key41.spi = esp1->spi;

          if (key41.as_u64 == last_key4.as_u64)
            {
              tid1 = last_tunnel_id;
            }
          else
            {
              uword *p =
                hash_get (im->ipsec4_if_pool_index_by_key, key41.as_u64);
              if (p)
                {
                  tid1 = p[0];
                  last_tunnel_id = tid1;
                  last_key4.as_u64 = key41.as_u64;
                }
              else
                {
                  next[1] =
                    ipsec_ip4_if_no_tunnel (node, b[1], esp1, ip41,
                                            buf_rewind1);
                  n_no_tunnel++;
                  goto trace1;
                }
            }
        }

      t1 = pool_elt_at_index (im->tunnel_interfaces, tid1);
      vnet_buffer (b[1])->ipsec.sad_index = t1->input_sa_index;

      if (PREDICT_TRUE (t1->hw_if_index != ~0))
        {
          sw_if_index1 = t1->sw_if_index;
          vnet_buffer (b[1])->sw_if_index[VLIB_RX] = sw_if_index1;

          if (PREDICT_FALSE (!(t1->flags & VNET_HW_INTERFACE_FLAG_LINK_UP)))
            {
              vlib_increment_combined_counter
                (drop_counter, thread_index, sw_if_index1, 1, len1);
              n_disabled++;
              b[1]->error = node->errors[IPSEC_IF_INPUT_ERROR_DISABLED];
              next[1] = IPSEC_INPUT_NEXT_DROP;
              goto trace1;
            }

          if (PREDICT_TRUE (sw_if_index1 == last_sw_if_index))
            {
              n_packets++;
              n_bytes += len1;
            }
          else
            {
              if (n_packets)
                {
                  vlib_increment_combined_counter
                    (rx_counter, thread_index, last_sw_if_index,
                     n_packets, n_bytes);
                }

              last_sw_if_index = sw_if_index1;
              n_packets = 1;
              n_bytes = len1;
            }
        }

    trace1:
      if (PREDICT_FALSE (is_trace))
        {
          if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
            {
              ipsec_if_input_trace_t *tr =
                vlib_add_trace (vm, node, b[0], sizeof (*tr));
              if (is_ip6)
                clib_memcpy (&tr->key6, &key60, sizeof (tr->key6));
              else
                clib_memcpy (&tr->key4, &key40, sizeof (tr->key4));
              tr->is_ip6 = is_ip6;
              tr->seq =
                len0 >=
                sizeof (*esp0) ? clib_host_to_net_u32 (esp0->seq) : ~0;
            }
          if (b[1]->flags & VLIB_BUFFER_IS_TRACED)
            {
              ipsec_if_input_trace_t *tr =
                vlib_add_trace (vm, node, b[1], sizeof (*tr));
              if (is_ip6)
                clib_memcpy (&tr->key6, &key61, sizeof (tr->key6));
              else
                clib_memcpy (&tr->key4, &key41, sizeof (tr->key4));
              tr->is_ip6 = is_ip6;
              tr->seq =
                len1 >=
                sizeof (*esp1) ? clib_host_to_net_u32 (esp1->seq) : ~0;
            }
        }

      /* next */
      b += 2;
      next += 2;
      n_left_from -= 2;
    }
  while (n_left_from > 0)
    {
      u32 sw_if_index0;
      ip4_header_t *ip40;
      ip6_header_t *ip60;
      esp_header_t *esp0;
      u32 len0;
      u16 buf_adv0, buf_rewind0;
      u32 tid0;
      ipsec_tunnel_if_t *t0;
      ipsec4_tunnel_key_t key40;
      ipsec6_tunnel_key_t key60;

      ip40 =
        (ip4_header_t *) (b[0]->data + vnet_buffer (b[0])->l3_hdr_offset);

      if (is_ip6)
        {
          ip60 = (ip6_header_t *) ip40;
          esp0 = (esp_header_t *) ((u8 *) ip60 + sizeof (ip6_header_t));
          buf_adv0 = sizeof (ip6_header_t);
        }
      else
        {
          /* NAT UDP port 4500 case, don't advance any more */
          if (ip40->protocol == IP_PROTOCOL_UDP)
            {
              esp0 =
                (esp_header_t *) ((u8 *) ip40 + ip4_header_bytes (ip40) +
                                  sizeof (udp_header_t));
              buf_adv0 = 0;
              buf_rewind0 = ip4_header_bytes (ip40) + sizeof (udp_header_t);
            }
          else
            {
              esp0 = (esp_header_t *) ((u8 *) ip40 + ip4_header_bytes (ip40));
              buf_rewind0 = buf_adv0 = ip4_header_bytes (ip40);
            }
        }

      /* stats for the tunnel include all the data after the IP header
         just like a norml IP-IP tunnel */
      vlib_buffer_advance (b[0], buf_adv0);
      len0 = vlib_buffer_length_in_chain (vm, b[0]);

      if (len0 < sizeof (esp_header_t))
        {
          if (esp0->spi_bytes[0] == 0xff)
            b[0]->error = node->errors[IPSEC_IF_INPUT_ERROR_NAT_KEEPALIVE];
          else
            b[0]->error = node->errors[IPSEC_IF_INPUT_ERROR_TOO_SHORT];

          next[0] = IPSEC_INPUT_NEXT_DROP;
          goto trace00;
        }

      if (is_ip6)
        {
          key60.remote_ip = ip60->src_address;
          key60.spi = esp0->spi;

          if (memcmp (&key60, &last_key6, sizeof (last_key6)) == 0)
            {
              tid0 = last_tunnel_id;
            }
          else
            {
              uword *p =
                hash_get_mem (im->ipsec6_if_pool_index_by_key, &key60);
              if (p)
                {
                  tid0 = p[0];
                  last_tunnel_id = tid0;
                  clib_memcpy_fast (&last_key6, &key60, sizeof (key60));
                }
              else
                {
                  next[0] =
                    ipsec_ip6_if_no_tunnel (node, b[0], esp0, buf_adv0);
                  n_no_tunnel++;
                  goto trace00;
                }
            }
        }
      else                      /* !is_ip6 */
        {
          key40.remote_ip = ip40->src_address;
          key40.spi = esp0->spi;

          if (key40.as_u64 == last_key4.as_u64)
            {
              tid0 = last_tunnel_id;
            }
          else
            {
              uword *p =
                hash_get (im->ipsec4_if_pool_index_by_key, key40.as_u64);
              if (p)
                {
                  tid0 = p[0];
                  last_tunnel_id = tid0;
                  last_key4.as_u64 = key40.as_u64;
                }
              else
                {
                  next[0] =
                    ipsec_ip4_if_no_tunnel (node, b[0], esp0, ip40,
                                            buf_rewind0);
                  n_no_tunnel++;
                  goto trace00;
                }
            }
        }

      t0 = pool_elt_at_index (im->tunnel_interfaces, tid0);
      vnet_buffer (b[0])->ipsec.sad_index = t0->input_sa_index;

      if (PREDICT_TRUE (t0->hw_if_index != ~0))
        {
          sw_if_index0 = t0->sw_if_index;
          vnet_buffer (b[0])->sw_if_index[VLIB_RX] = sw_if_index0;

          if (PREDICT_FALSE (!(t0->flags & VNET_HW_INTERFACE_FLAG_LINK_UP)))
            {
              vlib_increment_combined_counter
                (drop_counter, thread_index, sw_if_index0, 1, len0);
              n_disabled++;
              b[0]->error = node->errors[IPSEC_IF_INPUT_ERROR_DISABLED];
              next[0] = IPSEC_INPUT_NEXT_DROP;
              goto trace00;
            }

          if (PREDICT_TRUE (sw_if_index0 == last_sw_if_index))
            {
              n_packets++;
              n_bytes += len0;
            }
          else
            {
              if (n_packets)
                {
                  vlib_increment_combined_counter
                    (rx_counter, thread_index, last_sw_if_index,
                     n_packets, n_bytes);
                }

              last_sw_if_index = sw_if_index0;
              n_packets = 1;
              n_bytes = len0;
            }
        }

    trace00:
      if (PREDICT_FALSE (is_trace))
        {
          if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
            {
              ipsec_if_input_trace_t *tr =
                vlib_add_trace (vm, node, b[0], sizeof (*tr));
              if (is_ip6)
                clib_memcpy (&tr->key6, &key60, sizeof (tr->key6));
              else
                clib_memcpy (&tr->key4, &key40, sizeof (tr->key4));
              tr->is_ip6 = is_ip6;
              tr->seq =
                len0 >=
                sizeof (*esp0) ? clib_host_to_net_u32 (esp0->seq) : ~0;
            }
        }

      /* next */
      b += 1;
      next += 1;
      n_left_from -= 1;
    }

  if (n_packets)
    {
      vlib_increment_combined_counter (rx_counter,
                                       thread_index,
                                       last_sw_if_index, n_packets, n_bytes);
    }

  vlib_node_increment_counter (vm, node->node_index,
                               IPSEC_IF_INPUT_ERROR_RX,
                               from_frame->n_vectors - (n_disabled +
                                                        n_no_tunnel));

  vlib_buffer_enqueue_to_next (vm, node, from, nexts, from_frame->n_vectors);

  return from_frame->n_vectors;
}

VLIB_NODE_FN (ipsec4_if_input_node) (vlib_main_t * vm,
                                     vlib_node_runtime_t * node,
                                     vlib_frame_t * from_frame)
{
  return ipsec_if_input_inline (vm, node, from_frame, 0 /* is_ip6 */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ipsec4_if_input_node) = {
  .name = "ipsec4-if-input",
  .vector_size = sizeof (u32),
  .format_trace = format_ipsec_if_input_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(ipsec_if_input_error_strings),
  .error_strings = ipsec_if_input_error_strings,
  .sibling_of = "ipsec4-input-feature",
};
/* *INDENT-ON* */

VLIB_NODE_FN (ipsec6_if_input_node) (vlib_main_t * vm,
                                     vlib_node_runtime_t * node,
                                     vlib_frame_t * from_frame)
{
  return ipsec_if_input_inline (vm, node, from_frame, 1 /* is_ip6 */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ipsec6_if_input_node) = {
  .name = "ipsec6-if-input",
  .vector_size = sizeof (u32),
  .format_trace = format_ipsec_if_input_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(ipsec_if_input_error_strings),
  .error_strings = ipsec_if_input_error_strings,
  .sibling_of = "ipsec6-input-feature",
};
/* *INDENT-ON* */

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