/*
 * decap.c : IPSec tunnel support
 *
 * 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/interface.h>

#include <vnet/ipsec/ipsec.h>
#include <vnet/ipsec/esp.h>
#include <vnet/ipsec/ikev2.h>

int
ipsec_set_interface_spd(vlib_main_t * vm, u32 sw_if_index, u32 spd_id, int is_add)
{
  ipsec_main_t *im = &ipsec_main;
  ip_lookup_main_t * lm;
  ip_config_main_t * rx_cm;
  ip4_ipsec_config_t config;

  u32 spd_index, ci;
  uword *p;

  p = hash_get (im->spd_index_by_spd_id, spd_id);
  if (!p)
    return VNET_API_ERROR_SYSCALL_ERROR_1; /* no such spd-id */

  spd_index = p[0];

  p = hash_get (im->spd_index_by_sw_if_index, sw_if_index);
  if (p && is_add)
    return VNET_API_ERROR_SYSCALL_ERROR_1; /* spd already assigned */

  if (is_add)
    {
      hash_set (im->spd_index_by_sw_if_index, sw_if_index, spd_index);
    }
  else
    {
      hash_unset (im->spd_index_by_sw_if_index, sw_if_index);
    }

  clib_warning("sw_if_index %u spd_id %u spd_index %u",
               sw_if_index, spd_id, spd_index);

  /* enable IPsec on TX */
  vnet_interface_add_del_feature(im->vnet_main, vm, sw_if_index, 
                                 INTF_OUTPUT_FEAT_IPSEC, is_add);

  /* enable IPsec on RX */
  config.spd_index = spd_index;

  /* IPv4 */
  lm = &ip4_main.lookup_main;
  rx_cm = &lm->rx_config_mains[VNET_UNICAST];

  ci = rx_cm->config_index_by_sw_if_index[sw_if_index];

  ci = (is_add ? vnet_config_add_feature : vnet_config_del_feature)
    (vm, &rx_cm->config_main,
     ci,
     IP4_RX_FEATURE_IPSEC,
     &config,
     sizeof (config));
  rx_cm->config_index_by_sw_if_index[sw_if_index] = ci;

  /* IPv6 */
  lm = &ip6_main.lookup_main;
  rx_cm = &lm->rx_config_mains[VNET_UNICAST];

  ci = rx_cm->config_index_by_sw_if_index[sw_if_index];

  ci = (is_add ? vnet_config_add_feature : vnet_config_del_feature)
    (vm, &rx_cm->config_main,
     ci,
     IP6_RX_FEATURE_IPSEC,
     &config,
     sizeof (config));
  rx_cm->config_index_by_sw_if_index[sw_if_index] = ci;

  return 0;
}

int
ipsec_add_del_spd(vlib_main_t * vm, u32 spd_id, int is_add)
{
  ipsec_main_t *im = &ipsec_main;
  ipsec_spd_t * spd = 0;
  uword *p;
  u32 spd_index, k, v;

  p = hash_get (im->spd_index_by_spd_id, spd_id);
  if (p && is_add)
    return VNET_API_ERROR_INVALID_VALUE;
  if (!p && !is_add)
    return VNET_API_ERROR_INVALID_VALUE;

  if (!is_add) /* delete */
    {
      spd_index = p[0];
      spd = pool_elt_at_index(im->spds, spd_index);
      if (!spd)
        return VNET_API_ERROR_INVALID_VALUE;
      hash_foreach (k, v, im->spd_index_by_sw_if_index, ({
        if (v == spd_index)
          ipsec_set_interface_spd(vm, k, spd_id, 0);
      }));
      hash_unset (im->spd_index_by_spd_id, spd_id);
      pool_free (spd->policies);
      vec_free (spd->ipv4_outbound_policies);
      vec_free (spd->ipv6_outbound_policies);
      vec_free (spd->ipv4_inbound_protect_policy_indices);
      vec_free (spd->ipv4_inbound_policy_discard_and_bypass_indices);
      pool_put (im->spds, spd);
    }
  else /* create new SPD */
    {
      pool_get (im->spds, spd);
      memset (spd, 0, sizeof (*spd));
      spd_index = spd - im->spds;
      spd->id = spd_id;
      hash_set (im->spd_index_by_spd_id, spd_id, spd_index);
    }
  return 0;
}

static int
ipsec_spd_entry_sort(void * a1, void * a2)
{
  ipsec_main_t *im = &ipsec_main;
  u32 * id1 = a1;
  u32 * id2 = a2;
  ipsec_spd_t * spd;
  ipsec_policy_t * p1, * p2;

  pool_foreach (spd, im->spds, ({
    p1 = pool_elt_at_index(spd->policies, *id1);
    p2 = pool_elt_at_index(spd->policies, *id2);
    if (p1 && p2)
      return p2->priority - p1->priority;
  }));

  return 0;
}

int
ipsec_add_del_policy(vlib_main_t * vm, ipsec_policy_t * policy, int is_add)
{
  ipsec_main_t *im = &ipsec_main;
  ipsec_spd_t * spd = 0;
  ipsec_policy_t * vp;
  uword *p;
  u32 spd_index;

  clib_warning("policy-id %u priority %d is_outbound %u",policy->id, policy->priority, policy->is_outbound);

  if (policy->policy == IPSEC_POLICY_ACTION_PROTECT)
    {
      p = hash_get(im->sa_index_by_sa_id, policy->sa_id);
      if (!p)
        return VNET_API_ERROR_SYSCALL_ERROR_1;
      policy->sa_index = p[0];
    }

  p = hash_get (im->spd_index_by_spd_id, policy->id);

  if (!p)
    return VNET_API_ERROR_SYSCALL_ERROR_1;

  spd_index = p[0];
  spd = pool_elt_at_index(im->spds, spd_index);
  if (!spd)
    return VNET_API_ERROR_SYSCALL_ERROR_1;

  if (is_add)
    {
      u32 policy_index;

      pool_get (spd->policies, vp);
      memcpy (vp, policy, sizeof (*vp));
      policy_index = vp - spd->policies;

      if (policy->is_outbound)
        {
          if (policy->is_ipv6)
            {
              vec_add1 (spd->ipv6_outbound_policies, policy_index);
              memcpy(vp, policy, sizeof(ipsec_policy_t));
              vec_sort_with_function (spd->ipv6_outbound_policies,
                                      ipsec_spd_entry_sort);
            }
          else
            {
              vec_add1 (spd->ipv4_outbound_policies, policy_index);
              memcpy(vp, policy, sizeof(ipsec_policy_t));
              vec_sort_with_function (spd->ipv4_outbound_policies,
                                      ipsec_spd_entry_sort);
            }
        }
      else
        {
          if (policy->is_ipv6)
            {
              if (policy->policy == IPSEC_POLICY_ACTION_PROTECT)
                {
                  vec_add1 (spd->ipv6_inbound_protect_policy_indices,
                            policy_index);
                  memcpy(vp, policy, sizeof(ipsec_policy_t));
                  vec_sort_with_function (
                     spd->ipv6_inbound_protect_policy_indices,
                     ipsec_spd_entry_sort);
                }
              else
                {
                  vec_add1 (spd->ipv6_inbound_policy_discard_and_bypass_indices,
                            policy_index);
                  memcpy(vp, policy, sizeof(ipsec_policy_t));
                  vec_sort_with_function (
                     spd->ipv6_inbound_policy_discard_and_bypass_indices,
                     ipsec_spd_entry_sort);
                }
            }
          else
            {
              if (policy->policy == IPSEC_POLICY_ACTION_PROTECT)
                {
                  vec_add1 (spd->ipv4_inbound_protect_policy_indices,
                            policy_index);
                  memcpy(vp, policy, sizeof(ipsec_policy_t));
                  vec_sort_with_function (
                     spd->ipv4_inbound_protect_policy_indices,
                     ipsec_spd_entry_sort);
                }
              else
                {
                  vec_add1 (spd->ipv4_inbound_policy_discard_and_bypass_indices,
                            policy_index);
                  memcpy(vp, policy, sizeof(ipsec_policy_t));
                  vec_sort_with_function (
                    spd->ipv4_inbound_policy_discard_and_bypass_indices,
                    ipsec_spd_entry_sort);
                }
            }
        }

    }
  else
    {
      u32 i, j;
      pool_foreach_index(i, spd->policies, ({
        vp = pool_elt_at_index(spd->policies, i); 
        if (vp->priority != policy->priority)
          continue;
        if (vp->is_outbound != policy->is_outbound)
          continue;
        if (vp->policy != policy->policy)
          continue;
        if (vp->sa_id != policy->sa_id)
          continue;
        if (vp->protocol != policy->protocol)
          continue;
        if (vp->lport.start != policy->lport.start)
          continue;
        if (vp->lport.stop != policy->lport.stop)
          continue;
        if (vp->rport.start != policy->rport.start)
          continue;
        if (vp->rport.stop != policy->rport.stop)
          continue;
        if (vp->is_ipv6 != policy->is_ipv6)
          continue;
        if (policy->is_ipv6)
          {
            if (vp->laddr.start.ip6.as_u64[0] != policy->laddr.start.ip6.as_u64[0])
              continue;
            if (vp->laddr.start.ip6.as_u64[1] != policy->laddr.start.ip6.as_u64[1])
              continue;
            if (vp->laddr.stop.ip6.as_u64[0] != policy->laddr.stop.ip6.as_u64[0])
              continue;
            if (vp->laddr.stop.ip6.as_u64[1] != policy->laddr.stop.ip6.as_u64[1])
              continue;
            if (vp->raddr.start.ip6.as_u64[0] != policy->raddr.start.ip6.as_u64[0])
              continue;
            if (vp->raddr.start.ip6.as_u64[1] != policy->raddr.start.ip6.as_u64[1])
              continue;
            if (vp->raddr.stop.ip6.as_u64[0] != policy->raddr.stop.ip6.as_u64[0])
              continue;
           if (vp->laddr.stop.ip6.as_u64[1] != policy->laddr.stop.ip6.as_u64[1])
              continue;
           if (policy->is_outbound)
             {
               vec_foreach_index(j, spd->ipv6_outbound_policies) {
                 if (vec_elt(spd->ipv6_outbound_policies, j) == i) {
                   vec_del1 (spd->ipv6_outbound_policies, j);
                   break;
                 }
               }
             }
           else
             {
               if (policy->policy == IPSEC_POLICY_ACTION_PROTECT)
                 {
                   vec_foreach_index(j, spd->ipv6_inbound_protect_policy_indices) {
                     if (vec_elt(spd->ipv6_inbound_protect_policy_indices, j) == i) {
                       vec_del1 (spd->ipv6_inbound_protect_policy_indices, j);
                       break;
                     }
                   }
                 }
               else
                 {
                   vec_foreach_index(j, spd->ipv6_inbound_policy_discard_and_bypass_indices) {
                     if (vec_elt(spd->ipv6_inbound_policy_discard_and_bypass_indices, j) == i) {
                       vec_del1 (spd->ipv6_inbound_policy_discard_and_bypass_indices, j);
                       break;
                     }
                   }
                 }
             }
          }
        else
          {
            if (vp->laddr.start.ip4.as_u32 != policy->laddr.start.ip4.as_u32)
              continue;
            if (vp->laddr.stop.ip4.as_u32 != policy->laddr.stop.ip4.as_u32)
              continue;
            if (vp->raddr.start.ip4.as_u32 != policy->raddr.start.ip4.as_u32)
              continue;
            if (vp->raddr.stop.ip4.as_u32 != policy->raddr.stop.ip4.as_u32)
              continue;
            if (policy->is_outbound)
              {
                vec_foreach_index(j, spd->ipv4_outbound_policies) {
                  if (vec_elt(spd->ipv4_outbound_policies, j) == i) {
                    vec_del1 (spd->ipv4_outbound_policies, j);
                    break;
                  }
                } 
              }
            else
              {
                if (policy->policy == IPSEC_POLICY_ACTION_PROTECT)
                  {
                    vec_foreach_index(j, spd->ipv4_inbound_protect_policy_indices) {
                      if (vec_elt(spd->ipv4_inbound_protect_policy_indices, j) == i) {
                        vec_del1 (spd->ipv4_inbound_protect_policy_indices, j);
                        break;
                      }
                    }
                  }
                else
                  {
                    vec_foreach_index(j, spd->ipv4_inbound_policy_discard_and_bypass_indices) {
                      if (vec_elt(spd->ipv4_inbound_policy_discard_and_bypass_indices, j) == i) {
                        vec_del1 (spd->ipv4_inbound_policy_discard_and_bypass_indices, j);
                        break;
                    }
                  }
              }
          }
          pool_put (spd->policies, vp);
          break;
        }
      }));
    }

  return 0;
}

static u8
ipsec_is_sa_used(u32 sa_index)
{
  ipsec_main_t * im = &ipsec_main;
  ipsec_spd_t * spd;
  ipsec_policy_t * p;

  pool_foreach(spd, im->spds, ({
    pool_foreach(p, spd->policies, ({
      if (p->policy == IPSEC_POLICY_ACTION_PROTECT)
        {
          if (p->sa_index == sa_index)
            return 1;
        }
    }));
  }));

  return 0;
}

int
ipsec_add_del_sa(vlib_main_t * vm, ipsec_sa_t * new_sa, int is_add)
{
  ipsec_main_t *im = &ipsec_main;
  ipsec_sa_t * sa = 0;
  uword *p;
  u32 sa_index;

  clib_warning("id %u spi %u", new_sa->id, new_sa->spi);

  p = hash_get (im->sa_index_by_sa_id, new_sa->id);
  if (p && is_add)
    return VNET_API_ERROR_SYSCALL_ERROR_1; /* already exists */
  if (!p && !is_add)
    return VNET_API_ERROR_SYSCALL_ERROR_1;

  if (!is_add) /* delete */
    {
      sa_index = p[0];
      sa = pool_elt_at_index(im->sad, sa_index);
      if (ipsec_is_sa_used(sa_index))
        {
          clib_warning("sa_id %u used in policy", sa->id);
          return VNET_API_ERROR_SYSCALL_ERROR_1; /* sa used in policy */
        }
      hash_unset (im->sa_index_by_sa_id, sa->id);
      pool_put (im->sad, sa);
    }
  else /* create new SA */
    {
      pool_get (im->sad, sa);
      memcpy (sa, new_sa, sizeof (*sa));
      sa_index = sa - im->sad;
      hash_set (im->sa_index_by_sa_id, sa->id, sa_index);
    }
  return 0;
}

int
ipsec_set_sa_key(vlib_main_t * vm, ipsec_sa_t * sa_update)
{
  ipsec_main_t *im = &ipsec_main;
  uword *p;
  u32 sa_index;
  ipsec_sa_t * sa = 0;

  p = hash_get (im->sa_index_by_sa_id, sa_update->id);
  if (!p)
    return VNET_API_ERROR_SYSCALL_ERROR_1; /* no such sa-id */

  sa_index = p[0];
  sa = pool_elt_at_index(im->sad, sa_index);

  /* new crypto key */
  if (0 < sa_update->crypto_key_len)
    {
      memcpy(sa->crypto_key, sa_update->crypto_key, sa_update->crypto_key_len);
      sa->crypto_key_len = sa_update->crypto_key_len;
    }

  /* new integ key */
  if (0 < sa_update->integ_key_len)
    {
      memcpy(sa->integ_key, sa_update->integ_key, sa_update->integ_key_len);
      sa->integ_key_len = sa_update->integ_key_len;
    }

  return 0;
}

static void
ipsec_rand_seed(void)
{
  struct {
    time_t time;
    pid_t pid;
    void * p;
  } seed_data;

  seed_data.time = time(NULL);
  seed_data.pid = getpid();
  seed_data.p = (void *)&seed_data;

  RAND_seed((const void *)&seed_data, sizeof(seed_data));
}

static clib_error_t *
ipsec_init (vlib_main_t * vm)
{
  clib_error_t * error;
  ipsec_main_t * im = &ipsec_main;
  vlib_node_t * node;

  ipsec_rand_seed();

  memset (im, 0, sizeof (im[0]));

  im->vnet_main = vnet_get_main();
  im->vlib_main = vm;

  im->spd_index_by_spd_id      = hash_create (0, sizeof (uword));
  im->sa_index_by_sa_id        = hash_create (0, sizeof (uword));
  im->spd_index_by_sw_if_index = hash_create (0, sizeof (uword));

  node = vlib_get_node_by_name (vm, (u8 *) "error-drop");
  ASSERT(node);
  im->error_drop_node_index = node->index;

  node = vlib_get_node_by_name (vm, (u8 *) "esp-encrypt");
  ASSERT(node);
  im->esp_encrypt_node_index = node->index;

  node = vlib_get_node_by_name (vm, (u8 *) "ip4-lookup");
  ASSERT(node);
  im->ip4_lookup_node_index = node->index;


  if ((error = vlib_call_init_function (vm, ipsec_cli_init)))
    return error;

  if ((error = vlib_call_init_function (vm, ipsec_tunnel_if_init)))
    return error;

  esp_init();

  if ((error = ikev2_init (vm)))
    return error;

  return 0;
}

VLIB_INIT_FUNCTION (ipsec_init);