/*
 * 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/flow/flow_report.h>
#include <vnet/flow/flow_report_classify.h>
#include <vnet/api_errno.h>

/* Common prefix of tcp and udp headers
 * containing only source and destination port fields */
typedef struct {
  u16 src_port, dst_port;
} tcpudp_header_t;

flow_report_classify_main_t flow_report_classify_main;

u8 * ipfix_classify_template_rewrite (flow_report_main_t * frm,
                                      flow_report_t * fr,
                                      ip4_address_t * collector_address,
                                      ip4_address_t * src_address,
                                      u16 collector_port)
{
  flow_report_classify_main_t * fcm = &flow_report_classify_main;
  vnet_classify_table_t * tblp;
  vnet_classify_main_t * vcm = &vnet_classify_main;
  u32 flow_table_index = fr->opaque.as_uword;
  u8 * ip_start;
  ip4_header_t * ip;
  ip6_header_t * ip6;
  tcpudp_header_t * tcpudp;
  udp_header_t * udp;
  ipfix_message_header_t * h;
  ipfix_set_header_t * s;
  ipfix_template_header_t * t;
  ipfix_field_specifier_t * f;
  ipfix_field_specifier_t * first_field;
  u8 * rewrite = 0;
  ip4_ipfix_template_packet_t * tp;
  i32 l3_offset = -2;  /* sizeof (ethernet_header_t) - sizeof (u32x4) */
  u32 field_count = 0;
  u32 field_index = 0;
  flow_report_stream_t * stream;
  u8 ip_version;
  u8 transport_protocol;

  stream = &frm->streams[fr->stream_index];

  ipfix_classify_table_t * table = &fcm->tables[flow_table_index];

  ip_version = table->ip_version;
  transport_protocol = table->transport_protocol;

  tblp = pool_elt_at_index (vcm->tables, table->classify_table_index);

  /* 
   * Mumble, assumes that we're not classifying on L2 or first 2 octets
   * of L3..
   */

  /* Determine field count */
  ip_start = ((u8 *)(tblp->mask)) + l3_offset;
#define _(field,mask,item,length)                                       \
  if (memcmp(&field, &mask, length) == 0)                               \
    {                                                                   \
      field_count++;                                                    \
                                                                        \
      fr->fields_to_send = clib_bitmap_set (fr->fields_to_send,         \
                                            field_index, 1);            \
    }                                                                   \
  field_index++;
  foreach_ipfix_field;
#undef _

  /* Add packetTotalCount manually */
  field_count += 1;

  /* $$$ enterprise fields, at some later date */

  /* allocate rewrite space */
  vec_validate_aligned (rewrite, 
                        sizeof (ip4_ipfix_template_packet_t) 
                        + field_count * sizeof (ipfix_field_specifier_t) - 1,
                        CLIB_CACHE_LINE_BYTES);

  tp = (ip4_ipfix_template_packet_t *) rewrite;
  ip = (ip4_header_t *) &tp->ip4;
  udp = (udp_header_t *) (ip+1);
  h = (ipfix_message_header_t *)(udp+1);
  s = (ipfix_set_header_t *)(h+1);
  t = (ipfix_template_header_t *)(s+1);
  first_field = f = (ipfix_field_specifier_t *)(t+1);

  ip->ip_version_and_header_length = 0x45;
  ip->ttl = 254;
  ip->protocol = IP_PROTOCOL_UDP;
  ip->src_address.as_u32 = src_address->as_u32;
  ip->dst_address.as_u32 = collector_address->as_u32;
  udp->src_port = clib_host_to_net_u16 (stream->src_port);
  udp->dst_port = clib_host_to_net_u16 (collector_port);
  udp->length = clib_host_to_net_u16 (vec_len(rewrite) - sizeof (*ip));

  /* FIXUP: message header export_time */ 
  /* FIXUP: message header sequence_number */
  h->domain_id = clib_host_to_net_u32 (stream->domain_id);

  /* Take another trip through the mask and build the template */
  ip_start = ((u8 *)(tblp->mask)) + l3_offset;
#define _(field,mask,item,length)                               \
  if (memcmp(&field, &mask, length) == 0)                       \
    {                                                           \
      f->e_id_length = ipfix_e_id_length (0 /* enterprise */,   \
                                          item, length);        \
      f++;                                                      \
    }
  foreach_ipfix_field;
#undef _

  /* Add packetTotalCount manually */
  f->e_id_length = ipfix_e_id_length (0 /* enterprise */, packetTotalCount, 8);
  f++;

  /* Back to the template packet... */
  ip = (ip4_header_t *) &tp->ip4;
  udp = (udp_header_t *) (ip+1);
  
  ASSERT (f - first_field);
  /* Field count in this template */
  t->id_count = ipfix_id_count (fr->template_id, f - first_field);

  /* set length in octets*/
  s->set_id_length = ipfix_set_id_length (2 /* set_id */, (u8 *) f - (u8 *)s);

  /* message length in octets */
  h->version_length = version_length ((u8 *)f - (u8 *)h);

  ip->length = clib_host_to_net_u16 ((u8 *)f - (u8 *)ip);
  ip->checksum = ip4_header_checksum (ip);

  return rewrite;
}

vlib_frame_t * ipfix_classify_send_flows (flow_report_main_t * frm,
                                          flow_report_t * fr,
                                          vlib_frame_t * f,
                                          u32 * to_next,
                                          u32 node_index)
{
  flow_report_classify_main_t * fcm = &flow_report_classify_main;
  vnet_classify_main_t * vcm = &vnet_classify_main;
  u32 flow_table_index = fr->opaque.as_uword;
  vnet_classify_table_t * t;
  vnet_classify_bucket_t * b;
  vnet_classify_entry_t * v, * save_v;
  vlib_buffer_t *b0 = 0;
  u32 next_offset = 0;
  u32 record_offset = 0;
  u32 bi0 = ~0;
  int i, j, k;
  ip4_ipfix_template_packet_t * tp;
  ipfix_message_header_t * h = 0;
  ipfix_set_header_t * s = 0;
  u8 * ip_start;
  ip4_header_t * ip;
  ip6_header_t * ip6;
  tcpudp_header_t * tcpudp;
  udp_header_t * udp;
  int field_index;
  u32 records_this_buffer;
  u16 new_l0, old_l0;
  ip_csum_t sum0;
  vlib_main_t * vm = frm->vlib_main;
  flow_report_stream_t * stream;
  u8 ip_version;
  u8 transport_protocol;

  stream = &frm->streams[fr->stream_index];

  ipfix_classify_table_t * table = &fcm->tables[flow_table_index];

  ip_version = table->ip_version;
  transport_protocol = table->transport_protocol;

  t = pool_elt_at_index (vcm->tables, table->classify_table_index);
  
  while (__sync_lock_test_and_set (t->writer_lock, 1))
    ; 
  
  for (i = 0; i < t->nbuckets; i++)
    {
      b = &t->buckets [i];
      if (b->offset == 0)
        continue;
      
      save_v = vnet_classify_get_entry (t, b->offset);
      for (j = 0; j < (1<<b->log2_pages); j++)
        {
          for (k = 0; k < t->entries_per_page; k++)
            {
              v = vnet_classify_entry_at_index 
                (t, save_v, j*t->entries_per_page + k);
              
              if (vnet_classify_entry_is_free (v))
                continue;
              
              /* OK, we have something to send... */
              if (PREDICT_FALSE (b0 == 0))
                {
                  if (vlib_buffer_alloc (vm, &bi0, 1) != 1)
                    goto flush;
                  b0 = vlib_get_buffer (vm, bi0);
                  
                  u32 copy_len = sizeof(ip4_header_t) +
                                 sizeof(udp_header_t) +
                                 sizeof(ipfix_message_header_t);
                  clib_memcpy (b0->data, fr->rewrite, copy_len);
                  b0->current_data = 0;
                  b0->current_length = copy_len;
                  b0->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
                  vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
                  vnet_buffer (b0)->sw_if_index[VLIB_TX] = frm->fib_index;
                  
                  tp = vlib_buffer_get_current (b0);
                  ip = (ip4_header_t *) &tp->ip4;
                  udp = (udp_header_t *) (ip+1);
                  h = (ipfix_message_header_t *)(udp+1);
                  s = (ipfix_set_header_t *)(h+1);
                  
                  /* FIXUP: message header export_time */ 
                  h->export_time = (u32) 
                    (((f64)frm->unix_time_0) + 
                     (vlib_time_now(frm->vlib_main) - frm->vlib_time_0));
                  h->export_time = clib_host_to_net_u32(h->export_time);
                  
                  /* FIXUP: message header sequence_number */
                  h->sequence_number = stream->sequence_number;
                  h->sequence_number = clib_host_to_net_u32 (h->sequence_number);

                  next_offset = (u32) (((u8 *)(s+1)) - (u8 *)tp);
                  record_offset = next_offset;
                  records_this_buffer = 0;
                }

              field_index = 0;
              ip_start = ((u8 *)v->key) - 2;
#define _(field,mask,item,length)                                       \
              if (clib_bitmap_get (fr->fields_to_send, field_index))    \
                {                                                       \
                  clib_memcpy (b0->data + next_offset, &field,          \
                          length);                                      \
                  next_offset += length;                                \
                }                                                       \
              field_index++;
              foreach_ipfix_field;
#undef _

              /* Add packetTotalCount manually */
              {
                u64 packets = clib_host_to_net_u64 (v->hits);
                clib_memcpy (b0->data + next_offset, &packets, sizeof (packets));
                next_offset += sizeof (packets);
              }
              records_this_buffer++;
              stream->sequence_number++;
              
              /* Next record will have the same size as this record */
              u32 next_record_size = next_offset - record_offset;
              record_offset = next_offset;

              if (next_offset + next_record_size > frm->path_mtu)
                {
                  s->set_id_length = ipfix_set_id_length (fr->template_id,
                                                          next_offset - 
                                                          (sizeof (*ip) + sizeof (*udp) +
                                                           sizeof (*h)));
                  h->version_length = version_length (next_offset -
                                                      (sizeof (*ip) + sizeof (*udp)));
                  b0->current_length = next_offset;
                  b0->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
                  
                  tp = vlib_buffer_get_current (b0);
                  ip = (ip4_header_t *) &tp->ip4;
                  udp = (udp_header_t *) (ip+1);
                  
                  sum0 = ip->checksum;
                  old_l0 = ip->length;
                  new_l0 = 
                    clib_host_to_net_u16 ((u16)next_offset);
                  
                  sum0 = ip_csum_update (sum0, old_l0, new_l0, ip4_header_t,
                                         length /* changed member */);
                  
                  ip->checksum = ip_csum_fold (sum0);
                  ip->length = new_l0;
                  udp->length = 
                      clib_host_to_net_u16 (b0->current_length - sizeof (*ip));

                  if (frm->udp_checksum)
                    {
                      /* RFC 7011 section 10.3.2. */
                      udp->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ip);
                      if (udp->checksum == 0)
                        udp->checksum = 0xffff;
                    }

                  ASSERT (ip->checksum == ip4_header_checksum (ip));

                  to_next[0] = bi0;
                  f->n_vectors++;
                  to_next++;
                  
                  if (f->n_vectors == VLIB_FRAME_SIZE)
                    {
                      vlib_put_frame_to_node (vm, node_index, f);
                      f = vlib_get_frame_to_node (vm, node_index);
                      f->n_vectors = 0;
                      to_next = vlib_frame_vector_args (f);
                    }
                  b0 = 0;
                  bi0 = ~0;
                }
            }
        }
    }
  
 flush:
  if (b0)
    {
        s->set_id_length = ipfix_set_id_length (fr->template_id,
                                                next_offset - 
                                                (sizeof (*ip) + sizeof (*udp) +
                                                 sizeof (*h)));
        h->version_length = version_length (next_offset -
                                            (sizeof (*ip) + sizeof (*udp)));
      b0->current_length = next_offset;
      b0->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
      
      tp = vlib_buffer_get_current (b0);
      ip = (ip4_header_t *) &tp->ip4;
      udp = (udp_header_t *) (ip+1);
      
      sum0 = ip->checksum;
      old_l0 = ip->length;
      new_l0 = clib_host_to_net_u16 ((u16)next_offset);
      
      sum0 = ip_csum_update (sum0, old_l0, new_l0, ip4_header_t,
                             length /* changed member */);
      
      ip->checksum = ip_csum_fold (sum0);
      ip->length = new_l0;
      udp->length = clib_host_to_net_u16 (b0->current_length - sizeof (*ip));

      if (frm->udp_checksum)
        {
          /* RFC 7011 section 10.3.2. */
          udp->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ip);
          if (udp->checksum == 0)
          udp->checksum = 0xffff;
        }

      ASSERT (ip->checksum == ip4_header_checksum (ip));
      
      to_next[0] = bi0;
      f->n_vectors++;
      
      b0 = 0;
      bi0 = ~0;
    }
  
  *(t->writer_lock) = 0;
  return f;
}

static clib_error_t *
ipfix_classify_table_add_del_command_fn (vlib_main_t * vm,
                                         unformat_input_t * input,
                                         vlib_cli_command_t * cmd)
{
  flow_report_classify_main_t *fcm = &flow_report_classify_main;
  flow_report_main_t *frm = &flow_report_main;
  vnet_flow_report_add_del_args_t args;
  ipfix_classify_table_t * table;
  int rv;
  int is_add = -1;
  u32 classify_table_index = ~0;
  u8 ip_version = 0;
  u8 transport_protocol = 255;
  clib_error_t * error = 0;

  if (fcm->src_port == 0)
    clib_error_return (0, "call 'set ipfix classify stream' first");

  memset (&args, 0, sizeof (args));

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT) {
    if (unformat (input, "add"))
      is_add = 1;
    else if (unformat (input, "del"))
      is_add = 0;
    else if (unformat (input, "%d", &classify_table_index))
      ;
    else if (unformat (input, "ip4"))
      ip_version = 4;
    else if (unformat (input, "ip6"))
      ip_version = 6;
    else if (unformat (input, "tcp"))
      transport_protocol = 6;
    else if (unformat (input, "udp"))
      transport_protocol = 17;
    else
      return clib_error_return (0, "unknown input `%U'",
                                format_unformat_error, input);
  }

  if (is_add == -1)
    return clib_error_return (0, "expecting: add|del");
  if (classify_table_index == ~0)
    return clib_error_return (0, "classifier table not specified");
  if (ip_version == 0)
    return clib_error_return (0, "IP version not specified");

  table = 0;
  int i;
  for (i = 0; i < vec_len(fcm->tables); i++)
    if (ipfix_classify_table_index_valid(i))
      if (fcm->tables[i].classify_table_index == classify_table_index) {
        table = &fcm->tables[i];
        break;
      }

  if (is_add) {
    if (table)
      return clib_error_return (0, "Specified classifier table already used");
    table = ipfix_classify_add_table();
    table->classify_table_index = classify_table_index;
  } else {
    if (!table)
      return clib_error_return (0, "Specified classifier table not registered");
  }

  table->ip_version = ip_version;
  table->transport_protocol = transport_protocol;

  args.opaque.as_uword = table - fcm->tables;
  args.rewrite_callback = ipfix_classify_template_rewrite;
  args.flow_data_callback = ipfix_classify_send_flows;
  args.is_add = is_add;
  args.domain_id = fcm->domain_id;
  args.src_port = fcm->src_port;

  rv = vnet_flow_report_add_del (frm, &args);

  error = flow_report_add_del_error_to_clib_error(rv);

  /* If deleting, or add failed */
  if (is_add == 0 || (rv && is_add))
    ipfix_classify_delete_table (table - fcm->tables);

  return error;
}

VLIB_CLI_COMMAND (ipfix_classify_table_add_del_command, static) = {
  .path = "ipfix classify table",
  .short_help = "ipfix classify table add|del <table-index>",
  .function = ipfix_classify_table_add_del_command_fn,
};

static clib_error_t *
set_ipfix_classify_stream_command_fn (vlib_main_t * vm,
                                      unformat_input_t * input,
                                      vlib_cli_command_t * cmd)
{
  flow_report_classify_main_t *fcm = &flow_report_classify_main;
  flow_report_main_t *frm = &flow_report_main;
  u32 domain_id = 1;
  u32 src_port = UDP_DST_PORT_ipfix;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT) {
    if (unformat (input, "domain %d", &domain_id))
      ;
    else if (unformat (input, "src-port %d", &src_port))
      ;
    else
      return clib_error_return (0, "unknown input `%U'",
                                format_unformat_error, input);
  }

  if (fcm->src_port != 0 &&
      (fcm->domain_id != domain_id ||
       fcm->src_port != (u16)src_port)) {
    int rv = vnet_stream_change (frm, fcm->domain_id, fcm->src_port,
                                 domain_id, (u16)src_port);
    ASSERT (rv == 0);
  }

  fcm->domain_id = domain_id;
  fcm->src_port = (u16)src_port;

  return 0;
}

VLIB_CLI_COMMAND (set_ipfix_classify_stream_command, static) = {
  .path = "set ipfix classify stream",
  .short_help = "set ipfix classify stream"
                "[domain <domain-id>] [src-port <src-port>]",
  .function = set_ipfix_classify_stream_command_fn,
};

static clib_error_t *
flow_report_classify_init (vlib_main_t *vm)
{
  clib_error_t * error;

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

  return 0;
}

VLIB_INIT_FUNCTION (flow_report_classify_init);
