ah_encrypt.c

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/*
 * ah_encrypt.c : IPSec AH encrypt 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/ah.h>

#define foreach_ah_encrypt_next \
  _ (DROP, "error-drop")                           \
  _ (HANDOFF, "handoff")                           \
  _ (INTERFACE_OUTPUT, "interface-output")


#define _(v, s) AH_ENCRYPT_NEXT_##v,
typedef enum
{
  foreach_ah_encrypt_next
#undef _
    AH_ENCRYPT_N_NEXT,
} ah_encrypt_next_t;

#define foreach_ah_encrypt_error                                \
 _(RX_PKTS, "AH pkts received")                                 \
 _(CRYPTO_ENGINE_ERROR, "crypto engine error (packet dropped)") \
 _(SEQ_CYCLED, "sequence number cycled")


typedef enum
{
#define _(sym,str) AH_ENCRYPT_ERROR_##sym,
  foreach_ah_encrypt_error
#undef _
    AH_ENCRYPT_N_ERROR,
} ah_encrypt_error_t;

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

typedef struct
{
  u32 sa_index;
  u32 spi;
  u32 seq_lo;
  u32 seq_hi;
  ipsec_integ_alg_t integ_alg;
} ah_encrypt_trace_t;

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

  s = format (s, "ah: sa-index %d spi %u (0x%08x) seq %u:%u integrity %U",
              t->sa_index, t->spi, t->spi, t->seq_hi, t->seq_lo,
              format_ipsec_integ_alg, t->integ_alg);
  return s;
}

static_always_inline void
ah_process_ops (vlib_main_t * vm, vlib_node_runtime_t * node,
                vnet_crypto_op_t * ops, vlib_buffer_t * b[], u16 * nexts)
{
  u32 n_fail, n_ops = vec_len (ops);
  vnet_crypto_op_t *op = ops;

  if (n_ops == 0)
    return;

  n_fail = n_ops - vnet_crypto_process_ops (vm, op, n_ops);

  while (n_fail)
    {
      ASSERT (op - ops < n_ops);

      if (op->status != VNET_CRYPTO_OP_STATUS_COMPLETED)
        {
          u32 bi = op->user_data;
          b[bi]->error = node->errors[AH_ENCRYPT_ERROR_CRYPTO_ENGINE_ERROR];
          nexts[bi] = AH_ENCRYPT_NEXT_DROP;
          n_fail--;
        }
      op++;
    }
}

typedef struct
{
  union
  {
    struct
    {
      u8 hop_limit;
      u32 ip_version_traffic_class_and_flow_label;
    };

    struct
    {
      u8 ttl;
      u8 tos;
    };
  };
  i16 current_data;
  u8 skip;
  u32 sa_index;
} ah_encrypt_packet_data_t;

always_inline uword
ah_encrypt_inline (vlib_main_t * vm,
                   vlib_node_runtime_t * node, vlib_frame_t * frame,
                   int is_ip6)
{
  u32 n_left, *from, thread_index;
  int icv_size = 0;
  from = vlib_frame_vector_args (frame);
  n_left = frame->n_vectors;
  ipsec_main_t *im = &ipsec_main;
  ah_encrypt_packet_data_t pkt_data[VLIB_FRAME_SIZE], *pd = pkt_data;
  thread_index = vm->thread_index;
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
  u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
  ipsec_per_thread_data_t *ptd = vec_elt_at_index (im->ptd, thread_index);
  ipsec_sa_t *sa0 = 0;
  ip4_and_ah_header_t *ih0, *oh0 = 0;
  ip6_and_ah_header_t *ih6_0, *oh6_0 = 0;
  u32 current_sa_index = ~0, current_sa_bytes = 0, current_sa_pkts = 0;
  const static ip4_header_t ip4_hdr_template = {
    .ip_version_and_header_length = 0x45,
    .protocol = IP_PROTOCOL_IPSEC_AH,
  };
  const static ip6_header_t ip6_hdr_template = {
    .ip_version_traffic_class_and_flow_label = 0x60,
    .protocol = IP_PROTOCOL_IPSEC_AH,
  };

  clib_memset (pkt_data, 0, VLIB_FRAME_SIZE * sizeof (pkt_data[0]));
  vlib_get_buffers (vm, from, b, n_left);
  vec_reset_length (ptd->crypto_ops);
  vec_reset_length (ptd->integ_ops);

  while (n_left > 0)
    {
      u8 ip_hdr_size;
      u8 next_hdr_type;

      if (vnet_buffer (b[0])->ipsec.sad_index != current_sa_index)
        {
          if (current_sa_index != ~0)
            vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
                                             current_sa_index,
                                             current_sa_pkts,
                                             current_sa_bytes);
          current_sa_index = vnet_buffer (b[0])->ipsec.sad_index;
          sa0 = pool_elt_at_index (im->sad, current_sa_index);

          current_sa_bytes = current_sa_pkts = 0;
        }

      pd->sa_index = current_sa_index;
      next[0] = AH_ENCRYPT_NEXT_DROP;

      if (PREDICT_FALSE (~0 == sa0->encrypt_thread_index))
        {
          /* this is the first packet to use this SA, claim the SA
           * for this thread. this could happen simultaneously on
           * another thread */
          clib_atomic_cmp_and_swap (&sa0->encrypt_thread_index, ~0,
                                    ipsec_sa_assign_thread (thread_index));
        }

      if (PREDICT_TRUE (thread_index != sa0->encrypt_thread_index))
        {
          next[0] = AH_ENCRYPT_NEXT_HANDOFF;
          goto next;
        }

      if (PREDICT_FALSE (esp_seq_advance (sa0)))
        {
          b[0]->error = node->errors[AH_ENCRYPT_ERROR_SEQ_CYCLED];
          pd->skip = 1;
          goto next;
        }

      current_sa_pkts += 1;
      current_sa_bytes += b[0]->current_length;

      ssize_t adv;
      ih0 = vlib_buffer_get_current (b[0]);
      pd->ttl = ih0->ip4.ttl;
      pd->tos = ih0->ip4.tos;

      if (PREDICT_TRUE (ipsec_sa_is_set_IS_TUNNEL (sa0)))
        {
          if (is_ip6)
            adv = -sizeof (ip6_and_ah_header_t);
          else
            adv = -sizeof (ip4_and_ah_header_t);
        }
      else
        {
          adv = -sizeof (ah_header_t);
        }

      icv_size = sa0->integ_icv_size;
      const u8 padding_len = ah_calc_icv_padding_len (icv_size, is_ip6);
      adv -= padding_len;
      /* transport mode save the eth header before it is overwritten */
      if (PREDICT_FALSE (!ipsec_sa_is_set_IS_TUNNEL (sa0)))
        {
          const u32 l2_len = vnet_buffer (b[0])->ip.save_rewrite_length;
          u8 *l2_hdr_in = (u8 *) vlib_buffer_get_current (b[0]) - l2_len;

          u8 *l2_hdr_out = l2_hdr_in + adv - icv_size;

          clib_memcpy_le32 (l2_hdr_out, l2_hdr_in, l2_len);
        }

      vlib_buffer_advance (b[0], adv - icv_size);

      if (is_ip6)
        {
          ih6_0 = (ip6_and_ah_header_t *) ih0;
          ip_hdr_size = sizeof (ip6_header_t);
          oh6_0 = vlib_buffer_get_current (b[0]);
          pd->current_data = b[0]->current_data;

          pd->hop_limit = ih6_0->ip6.hop_limit;
          pd->ip_version_traffic_class_and_flow_label =
            ih6_0->ip6.ip_version_traffic_class_and_flow_label;
          if (PREDICT_TRUE (ipsec_sa_is_set_IS_TUNNEL (sa0)))
            {
              next_hdr_type = IP_PROTOCOL_IPV6;
            }
          else
            {
              next_hdr_type = ih6_0->ip6.protocol;
              memmove (oh6_0, ih6_0, sizeof (ip6_header_t));
            }

          clib_memcpy_fast (&oh6_0->ip6, &ip6_hdr_template, 8);
          oh6_0->ah.reserved = 0;
          oh6_0->ah.nexthdr = next_hdr_type;
          oh6_0->ah.spi = clib_net_to_host_u32 (sa0->spi);
          oh6_0->ah.seq_no = clib_net_to_host_u32 (sa0->seq);
          oh6_0->ip6.payload_length =
            clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b[0]) -
                                  sizeof (ip6_header_t));
          oh6_0->ah.hdrlen =
            (sizeof (ah_header_t) + icv_size + padding_len) / 4 - 2;
        }
      else
        {
          ip_hdr_size = sizeof (ip4_header_t);
          oh0 = vlib_buffer_get_current (b[0]);
          clib_memset (oh0, 0, sizeof (ip4_and_ah_header_t));
          pd->current_data = b[0]->current_data;

          if (PREDICT_TRUE (ipsec_sa_is_set_IS_TUNNEL (sa0)))
            {
              next_hdr_type = IP_PROTOCOL_IP_IN_IP;
            }
          else
            {
              next_hdr_type = ih0->ip4.protocol;
              memmove (oh0, ih0, sizeof (ip4_header_t));
            }

          clib_memcpy_fast (&oh0->ip4, &ip4_hdr_template,
                            sizeof (ip4_header_t) -
                            sizeof (ip4_address_pair_t));

          oh0->ip4.length =
            clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b[0]));
          oh0->ah.spi = clib_net_to_host_u32 (sa0->spi);
          oh0->ah.seq_no = clib_net_to_host_u32 (sa0->seq);
          oh0->ah.nexthdr = next_hdr_type;
          oh0->ah.hdrlen =
            (sizeof (ah_header_t) + icv_size + padding_len) / 4 - 2;
        }

      if (PREDICT_TRUE (!is_ip6 && ipsec_sa_is_set_IS_TUNNEL (sa0) &&
                        !ipsec_sa_is_set_IS_TUNNEL_V6 (sa0)))
        {
          clib_memcpy_fast (&oh0->ip4.address_pair,
                            &sa0->ip4_hdr.address_pair,
                            sizeof (ip4_address_pair_t));

          next[0] = sa0->dpo.dpoi_next_node;
          vnet_buffer (b[0])->ip.adj_index[VLIB_TX] = sa0->dpo.dpoi_index;
        }
      else if (is_ip6 && ipsec_sa_is_set_IS_TUNNEL (sa0) &&
               ipsec_sa_is_set_IS_TUNNEL_V6 (sa0))
        {
          clib_memcpy_fast (&oh6_0->ip6.src_address,
                            &sa0->ip6_hdr.src_address,
                            sizeof (ip6_address_t) * 2);
          next[0] = sa0->dpo.dpoi_next_node;
          vnet_buffer (b[0])->ip.adj_index[VLIB_TX] = sa0->dpo.dpoi_index;
        }

      if (PREDICT_TRUE (sa0->integ_op_id))
        {
          vnet_crypto_op_t *op;
          vec_add2_aligned (ptd->integ_ops, op, 1, CLIB_CACHE_LINE_BYTES);
          vnet_crypto_op_init (op, sa0->integ_op_id);
          op->src = vlib_buffer_get_current (b[0]);
          op->len = b[0]->current_length;
          op->digest = vlib_buffer_get_current (b[0]) + ip_hdr_size +
            sizeof (ah_header_t);
          clib_memset (op->digest, 0, icv_size);
          op->digest_len = icv_size;
          op->key_index = sa0->integ_key_index;
          op->user_data = b - bufs;
          if (ipsec_sa_is_set_USE_ESN (sa0))
            {
              u32 seq_hi = clib_host_to_net_u32 (sa0->seq_hi);

              op->len += sizeof (seq_hi);
              clib_memcpy (op->src + b[0]->current_length, &seq_hi,
                           sizeof (seq_hi));
            }
        }

      if (!ipsec_sa_is_set_IS_TUNNEL (sa0))
        {
          next[0] = AH_ENCRYPT_NEXT_INTERFACE_OUTPUT;
          vlib_buffer_advance (b[0], -sizeof (ethernet_header_t));
        }

    next:
      n_left -= 1;
      next += 1;
      pd += 1;
      b += 1;
    }

  n_left = frame->n_vectors;
  next = nexts;
  pd = pkt_data;
  b = bufs;

  vlib_node_increment_counter (vm, node->node_index,
                               AH_ENCRYPT_ERROR_RX_PKTS, n_left);
  vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
                                   current_sa_index, current_sa_pkts,
                                   current_sa_bytes);

  ah_process_ops (vm, node, ptd->integ_ops, bufs, nexts);

  while (n_left)
    {
      if (pd->skip)
        goto trace;

      if (is_ip6)
        {
          oh6_0 = (ip6_and_ah_header_t *) (b[0]->data + pd->current_data);
          oh6_0->ip6.hop_limit = pd->hop_limit;
          oh6_0->ip6.ip_version_traffic_class_and_flow_label =
            pd->ip_version_traffic_class_and_flow_label;
        }
      else
        {
          oh0 = (ip4_and_ah_header_t *) (b[0]->data + pd->current_data);
          oh0->ip4.ttl = pd->ttl;
          oh0->ip4.tos = pd->tos;
          oh0->ip4.checksum = ip4_header_checksum (&oh0->ip4);
        }

    trace:
      if (PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
        {
          sa0 = vec_elt_at_index (im->sad, pd->sa_index);
          ah_encrypt_trace_t *tr =
            vlib_add_trace (vm, node, b[0], sizeof (*tr));
          tr->spi = sa0->spi;
          tr->seq_lo = sa0->seq;
          tr->seq_hi = sa0->seq_hi;
          tr->integ_alg = sa0->integ_alg;
          tr->sa_index = pd->sa_index;
        }

      n_left -= 1;
      next += 1;
      pd += 1;
      b += 1;
    }

  n_left = frame->n_vectors;
  vlib_buffer_enqueue_to_next (vm, node, from, nexts, n_left);

  return n_left;
}

VLIB_NODE_FN (ah4_encrypt_node) (vlib_main_t * vm,
                                 vlib_node_runtime_t * node,
                                 vlib_frame_t * from_frame)
{
  return ah_encrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ah4_encrypt_node) = {
  .name = "ah4-encrypt",
  .vector_size = sizeof (u32),
  .format_trace = format_ah_encrypt_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

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

  .n_next_nodes = AH_ENCRYPT_N_NEXT,
  .next_nodes = {
    [AH_ENCRYPT_NEXT_DROP] = "ip4-drop",
    [AH_ENCRYPT_NEXT_HANDOFF] = "ah4-encrypt-handoff",
    [AH_ENCRYPT_NEXT_INTERFACE_OUTPUT] = "interface-output",
  },
};
/* *INDENT-ON* */

VLIB_NODE_FN (ah6_encrypt_node) (vlib_main_t * vm,
                                 vlib_node_runtime_t * node,
                                 vlib_frame_t * from_frame)
{
  return ah_encrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ah6_encrypt_node) = {
  .name = "ah6-encrypt",
  .vector_size = sizeof (u32),
  .format_trace = format_ah_encrypt_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

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

  .n_next_nodes = AH_ENCRYPT_N_NEXT,
  .next_nodes = {
    [AH_ENCRYPT_NEXT_DROP] = "ip6-drop",
    [AH_ENCRYPT_NEXT_HANDOFF] = "ah6-encrypt-handoff",
    [AH_ENCRYPT_NEXT_INTERFACE_OUTPUT] = "interface-output",
  },
};
/* *INDENT-ON* */

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