/*
 * ipsec_output.c : IPSec output 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>


#define foreach_ipsec_output_next                \
_(DROP, "error-drop")                            \
_(ESP_ENCRYPT, "esp-encrypt")

#define _(v, s) IPSEC_OUTPUT_NEXT_##v,
typedef enum {
  foreach_intf_output_feat
  foreach_ipsec_output_next
#undef _
  IPSEC_OUTPUT_N_NEXT,
} ipsec_output_next_t;


#define foreach_ipsec_output_error                   \
 _(RX_PKTS, "IPSec pkts received")                   \
 _(POLICY_DISCARD, "IPSec policy discard")           \
 _(POLICY_NO_MATCH, "IPSec policy (no match)")       \
 _(POLICY_PROTECT, "IPSec policy protect")           \
 _(POLICY_BYPASS, "IPSec policy bypass")             \
 _(ENCAPS_FAILED, "IPSec encapsulation failed")


typedef enum {
#define _(sym,str) IPSEC_OUTPUT_ERROR_##sym,
  foreach_ipsec_output_error
#undef _
  IPSEC_DECAP_N_ERROR,
} ipsec_output_error_t;

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

vlib_node_registration_t ipsec_output_node;

typedef struct {
  u32 spd_id;
} ipsec_output_trace_t;

/* packet trace format function */
static u8 * format_ipsec_output_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_output_trace_t * t = va_arg (*args, ipsec_output_trace_t *);

  if (t->spd_id != ~0)
  {
    s = format (s, "spd %u ", t->spd_id);
  }
  else
  {
    s = format (s, "no spd");
  }
  return s;
}

always_inline intf_output_feat_t
get_next_intf_output_feature_and_reset_bit(vlib_buffer_t *b)
{
  u32 next_feature;
  count_trailing_zeros(next_feature, vnet_buffer(b)->output_features.bitmap);
  if (next_feature != INTF_OUTPUT_FEAT_DONE)
    vnet_buffer(b)->output_features.bitmap &= ~(1 << next_feature);
  return next_feature;
}

always_inline ipsec_policy_t *
ipsec_output_policy_match(ipsec_spd_t * spd, u8 pr, u32 la, u32 ra, u16 lp, u16 rp)
{
  ipsec_policy_t * p;
  u32 * i;

  vec_foreach(i, spd->ipv4_outbound_policies)
    {
      p = pool_elt_at_index(spd->policies, *i);
      if (PREDICT_FALSE(p->protocol && (p->protocol != pr)))
      	continue;

      if (la < clib_net_to_host_u32(p->laddr.start.ip4.as_u32))
      	continue;

      if (la > clib_net_to_host_u32(p->laddr.stop.ip4.as_u32))
      	continue;

      if (ra < clib_net_to_host_u32(p->raddr.start.ip4.as_u32))
      	continue;

      if (ra > clib_net_to_host_u32(p->raddr.stop.ip4.as_u32))
      	continue;

      if (PREDICT_FALSE((pr != IP_PROTOCOL_TCP) && (pr != IP_PROTOCOL_UDP)))
      	return p;

      if (lp < p->lport.start)
      	continue;

      if (lp > p->lport.stop)
      	continue;

      if (rp < p->rport.start)
      	continue;

      if (rp > p->rport.stop)
      	continue;

      return p;
    }
    return 0;
}

always_inline uword
ip6_addr_match_range (ip6_address_t * a, ip6_address_t * la, ip6_address_t * ua)
{
  if ((memcmp(a->as_u64, la->as_u64, 2 * sizeof(u64)) >= 0) &&
      (memcmp(a->as_u64, ua->as_u64, 2 * sizeof(u64)) <= 0))
    return 1;
  return 0;
}

always_inline ipsec_policy_t *
ipsec_output_ip6_policy_match (ipsec_spd_t * spd,
                               ip6_address_t * sa,
                               ip6_address_t * da,
                               u16 lp,
                               u16 rp,
                               u8 pr)
{
  ipsec_policy_t * p;
  u32 * i;

  vec_foreach(i, spd->ipv6_outbound_policies)
    {
      p = pool_elt_at_index(spd->policies, *i);
      if (PREDICT_FALSE(p->protocol && (p->protocol != pr)))
        continue;

      if (!ip6_addr_match_range(sa, &p->raddr.start.ip6, &p->raddr.stop.ip6))
        continue;

      if (!ip6_addr_match_range(da, &p->laddr.start.ip6, &p->laddr.stop.ip6))
        continue;

      if (PREDICT_FALSE((pr != IP_PROTOCOL_TCP) && (pr != IP_PROTOCOL_UDP)))
        return p;

      if (lp < p->lport.start)
        continue;

      if (lp > p->lport.stop)
        continue;

      if (rp < p->rport.start)
        continue;

      if (rp > p->rport.stop)
        continue;

     return p;
    }

  return 0;
}
static uword
ipsec_output_node_fn (vlib_main_t * vm,
         vlib_node_runtime_t * node,
         vlib_frame_t * from_frame)
{
  ipsec_main_t *im = &ipsec_main;
  vnet_main_t * vnm = im->vnet_main;

  u32 * from, * to_next = 0;
  u32 n_left_from, sw_if_index0, last_sw_if_index = (u32) ~0;
  u32 next_node_index = (u32)~0, last_next_node_index = (u32) ~0;
  vlib_frame_t *f = 0;
  u32 spd_index0 = ~0;
  ipsec_spd_t * spd0 = 0;
  u64 nc_protect = 0, nc_bypass = 0, nc_discard = 0, nc_nomatch = 0;

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

  while (n_left_from > 0)
    {
      u32 bi0;
      vlib_buffer_t * b0;
      ipsec_policy_t * p0;
      ip4_header_t * ip0;
      ip6_header_t * ip6_0 = 0;
      udp_header_t * udp0;
      u8 is_ipv6 = 0;

      bi0 = from[0];
      b0 = vlib_get_buffer (vm, bi0);
      sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_TX];


      ip0 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b0) +
                              sizeof(ethernet_header_t));

      /* just forward non ipv4 packets */
      if (PREDICT_FALSE((ip0->ip_version_and_header_length & 0xF0 ) != 0x40))
      {
        /* ipv6 packets */
        if (PREDICT_TRUE((ip0->ip_version_and_header_length & 0xF0 ) == 0x60))
          {
            is_ipv6 = 1;
            ip6_0 = (ip6_header_t *) ((u8 *) vlib_buffer_get_current (b0) +
                                      sizeof(ethernet_header_t));
          }
        else
          {
            next_node_index = get_next_output_feature_node_index(vnm, b0);
            goto dispatch0;
          }
      }

      /* lookup for SPD only if sw_if_index is changed */
      if (PREDICT_FALSE(last_sw_if_index != sw_if_index0))
        {
           uword * p = hash_get (im->spd_index_by_sw_if_index, sw_if_index0);
           ASSERT(p);
           spd_index0 = p[0];
           spd0 = pool_elt_at_index(im->spds, spd_index0);
           last_sw_if_index = sw_if_index0;
        }

     if (is_ipv6)
        {
          udp0 = ip6_next_header(ip6_0);
#if 0
          clib_warning("packet received from %U port %u to %U port %u spd_id %u",
                       format_ip6_address, &ip6_0->src_address,
                       clib_net_to_host_u16(udp0->src_port),
                       format_ip6_address, &ip6_0->dst_address,
                       clib_net_to_host_u16(udp0->dst_port),
                       spd0->id);
#endif

          p0 = ipsec_output_ip6_policy_match(spd0,
                     &ip6_0->src_address,
                     &ip6_0->dst_address,
                     clib_net_to_host_u16(udp0->src_port),
                     clib_net_to_host_u16(udp0->dst_port),
                     ip6_0->protocol);
        }
      else
        {
          udp0 = (udp_header_t *) ((u8 *) ip0 + ip4_header_bytes (ip0));

#if 0
          clib_warning("packet received from %U to %U port %u",
                       format_ip4_address, ip0->src_address.as_u8,
                       format_ip4_address, ip0->dst_address.as_u8,
                       clib_net_to_host_u16(udp0->dst_port));
          clib_warning("sw_if_index0 %u spd_index0 %u spd_id %u",
                       sw_if_index0, spd_index0, spd0->id);
#endif

          p0 = ipsec_output_policy_match(spd0, ip0->protocol,
                     clib_net_to_host_u32(ip0->src_address.as_u32),
                     clib_net_to_host_u32(ip0->dst_address.as_u32),
                     clib_net_to_host_u16(udp0->src_port),
                     clib_net_to_host_u16(udp0->dst_port));
        }

      if (PREDICT_TRUE(p0 != NULL))
        {
      	  if (p0->policy == IPSEC_POLICY_ACTION_PROTECT)
      	    {
              nc_protect++;
      	      next_node_index = im->esp_encrypt_node_index;
      	      vnet_buffer(b0)->output_features.ipsec_sad_index = p0->sa_index;
              vlib_buffer_advance(b0, sizeof(ethernet_header_t));
              p0->counter.packets++;
              if (is_ipv6)
                {
                  p0->counter.bytes += clib_net_to_host_u16(ip6_0->payload_length);
                  p0->counter.bytes += sizeof(ip6_header_t);
                }
              else
                {
                  p0->counter.bytes += clib_net_to_host_u16(ip0->length);
                }
      	    }
      	  else if (p0->policy == IPSEC_POLICY_ACTION_BYPASS)
      	    {
              nc_bypass++;
      	      next_node_index = get_next_output_feature_node_index(vnm, b0);
              p0->counter.packets++;
              if (is_ipv6)
                {
                  p0->counter.bytes += clib_net_to_host_u16(ip6_0->payload_length);
                  p0->counter.bytes += sizeof(ip6_header_t);
                }
              else
                {
                  p0->counter.bytes += clib_net_to_host_u16(ip0->length);
                }
      	    }
      	  else
      	    {
              nc_discard++;
              p0->counter.packets++;
              if (is_ipv6)
                {
                  p0->counter.bytes += clib_net_to_host_u16(ip6_0->payload_length);
                  p0->counter.bytes += sizeof(ip6_header_t);
                }
              else
                {
                  p0->counter.bytes += clib_net_to_host_u16(ip0->length);
                }
              next_node_index = im->error_drop_node_index;
      	    }
        }
      else
        {
          nc_nomatch++;
          next_node_index = im->error_drop_node_index;
        }

dispatch0:
      from += 1;
      n_left_from -= 1;

      if (PREDICT_FALSE((last_next_node_index != next_node_index)))
        {
          /* if this is not 1st frame */
          if (f)
            vlib_put_frame_to_node (vm, last_next_node_index, f);

          last_next_node_index = next_node_index;

          f = vlib_get_frame_to_node(vm, next_node_index);
          to_next = vlib_frame_vector_args (f);
        }

      to_next[0] = bi0;
      to_next+=1;
      f->n_vectors++;

      if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED)) {
            ipsec_output_trace_t *tr = vlib_add_trace (vm, node, b0, sizeof (*tr));
            if (spd0)
              tr->spd_id = spd0->id;
      }
    }

  vlib_put_frame_to_node (vm, next_node_index, f);
  vlib_node_increment_counter (vm, ipsec_output_node.index,
                               IPSEC_OUTPUT_ERROR_POLICY_PROTECT, nc_protect);
  vlib_node_increment_counter (vm, ipsec_output_node.index,
                               IPSEC_OUTPUT_ERROR_POLICY_BYPASS, nc_bypass);
  vlib_node_increment_counter (vm, ipsec_output_node.index,
                               IPSEC_OUTPUT_ERROR_POLICY_DISCARD, nc_discard);
  vlib_node_increment_counter (vm, ipsec_output_node.index,
                               IPSEC_OUTPUT_ERROR_POLICY_NO_MATCH, nc_nomatch);
  return from_frame->n_vectors;
}

VLIB_REGISTER_NODE (ipsec_output_node) = {
  .function = ipsec_output_node_fn,
  .name = "ipsec-output",
  .vector_size = sizeof (u32),
  .format_trace = format_ipsec_output_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

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

  .n_next_nodes = IPSEC_OUTPUT_N_NEXT,
  .next_nodes = {
#define _(s,n) [IPSEC_OUTPUT_NEXT_##s] = n,
    foreach_intf_output_feat
    foreach_ipsec_output_next
#undef _
  },
};