/*
 * Copyright (c) 2017 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.
 */
/*
  Copyright (c) 2001, 2002, 2003, 2004 Eliot Dresselhaus

  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:

  The above copyright notice and this permission notice shall be
  included in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED 
/*
 * Copyright (c) 2017 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 <stn/stn.h>

#include <vnet/plugin/plugin.h>
#include <vpp/app/version.h>
#include <vnet/ip/format.h>
#include <vnet/ethernet/packet.h>
#include <vnet/udp/udp.h>
#include <vnet/tcp/tcp.h>

stn_main_t stn_main;
static vlib_node_registration_t stn_ip4_punt;
static vlib_node_registration_t stn_ip6_punt;

static u8 stn_hw_addr_local[6] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x01};
static u8 stn_hw_addr_dst[6] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x02};

static ethernet_header_t stn_ip4_ethernet_header = {};
static ethernet_header_t stn_ip6_ethernet_header = {};

typedef struct {
  clib_bihash_kv_16_8_t kv;
} stn_ip46_punt_trace_t;

static u8 *
format_stn_rule (u8 * s, va_list * args)
{
  stn_rule_t *r = va_arg (*args, stn_rule_t *);
  stn_main_t *stn = &stn_main;
  u32 indent = format_get_indent (s);
  u32 node_index = ip46_address_is_ip4(&r->address)?stn_ip4_punt.index:stn_ip6_punt.index;
  vlib_node_t *next_node = vlib_get_next_node(vlib_get_main(), node_index, r->next_node_index);
  s = format (s, "rule_index: %d\n", r - stn->rules);
  s = format (s, "%Uaddress: %U\n", format_white_space, indent,
	      format_ip46_address, &r->address, IP46_TYPE_ANY);
  s = format (s, "%Uiface: %U (%d)\n", format_white_space, indent,
  	      format_vnet_sw_if_index_name, vnet_get_main(), r->sw_if_index,
	      r->sw_if_index);
  s = format (s, "%Unext_node: %s (%d)", format_white_space, indent,
	      next_node->name, next_node->index);
  return s;
}

static_always_inline u8 *
format_stn_ip46_punt_trace (u8 * s, va_list * args, u8 is_ipv4)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  stn_ip46_punt_trace_t *t = va_arg (*args, stn_ip46_punt_trace_t *);
  u32 indent = format_get_indent (s);

  s = format (s, "dst_address: %U\n", format_ip46_address,
	  (ip46_address_t *)t->kv.key, IP46_TYPE_ANY);

  if (t->kv.value == ~(0L))
    {
      s = format (s, "%Urule: none", format_white_space, indent);
    }
  else
    {
      s = format (s, "%Urule:\n%U%U", format_white_space, indent,
		     format_white_space, indent + 2,
		     format_stn_rule, &stn_main.rules[t->kv.value]);
    }
  return s;
}

typedef enum
{
  STN_IP_PUNT_DROP,
  STN_IP_PUNT_N_NEXT,
} stn_ip_punt_next_t;

static_always_inline uword
stn_ip46_punt_fn (vlib_main_t * vm,
                  vlib_node_runtime_t * node,
                  vlib_frame_t * frame,
                  u8 is_ipv4)
{
  u32 n_left_from, *from, next_index, *to_next, n_left_to_next;
  stn_main_t *stn = &stn_main;

  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

      /* Single loop */
      while (n_left_from > 0 && n_left_to_next > 0)
	{
	  u32 pi0;
	  vlib_buffer_t *p0;
	  clib_bihash_kv_16_8_t kv;
	  u32 next0 = STN_IP_PUNT_DROP;

	  pi0 = to_next[0] = from[0];
	  from += 1;
	  n_left_from -= 1;
	  to_next += 1;
	  n_left_to_next -= 1;

	  p0 = vlib_get_buffer (vm, pi0);

	  if (is_ipv4)
	    {
	      ip4_header_t *hdr = (ip4_header_t *) vlib_buffer_get_current(p0);
	      ip46_address_set_ip4((ip46_address_t *)kv.key, &hdr->dst_address);
	    }
	  else
	    {
	      ip6_header_t *hdr = (ip6_header_t *) vlib_buffer_get_current(p0);
	      kv.key[0] = hdr->dst_address.as_u64[0];
	      kv.key[1] = hdr->dst_address.as_u64[1];
	    }

	  kv.value = ~(0L);
	  clib_bihash_search_inline_16_8 (&stn->rule_by_address_table, &kv);
	  if (kv.value != ~(0L))
	    {
	      ethernet_header_t *eth;
	      stn_rule_t *r = &stn->rules[kv.value];
	      vnet_buffer(p0)->sw_if_index[VLIB_TX] = r->sw_if_index;
	      next0 = r->next_node_index;
	      vlib_buffer_advance(p0, -sizeof(*eth));
	      eth = (ethernet_header_t *) vlib_buffer_get_current(p0);
	      if (is_ipv4)
		clib_memcpy_fast(eth, &stn_ip4_ethernet_header, sizeof(*eth));
	      else
		clib_memcpy_fast(eth, &stn_ip6_ethernet_header, sizeof(*eth));
	    }
          else
          {
              vnet_feature_next (&next0, p0);
          }

	  if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      stn_ip46_punt_trace_t *tr =
		  vlib_add_trace (vm, node, p0, sizeof (*tr));
	      tr->kv = kv;
	    }

	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
					   n_left_to_next, pi0, next0);
	}
      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  return frame->n_vectors;
}


#define foreach_stn_ip_punt_error \
 _(NONE, "no error")

typedef enum {
#define _(sym,str) STN_IP_punt_ERROR_##sym,
  foreach_stn_ip_punt_error
#undef _
  STN_IP_PUNT_N_ERROR,
} ila_error_t;

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

u8 *
format_stn_ip6_punt_trace (u8 * s, va_list * args)
{
  return format_stn_ip46_punt_trace (s, args, 0);
}

static uword
stn_ip6_punt_fn (vlib_main_t * vm,
	           vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  return stn_ip46_punt_fn(vm, node, frame, 0);
}

/** *INDENT-OFF* */
VLIB_REGISTER_NODE (stn_ip6_punt, static) =
{
  .function = stn_ip6_punt_fn,
  .name = "stn-ip6-punt",
  .vector_size = sizeof (u32),
  .format_trace = format_stn_ip6_punt_trace,
  .n_errors = STN_IP_PUNT_N_ERROR,
  .error_strings = stn_ip_punt_error_strings,
  .n_next_nodes = STN_IP_PUNT_N_NEXT,
  .next_nodes =
  {
      [STN_IP_PUNT_DROP] = "error-drop"
  },
};
VNET_FEATURE_INIT (stn_ip6_punt_feat_node, static) = {
  .arc_name = "ip6-punt",
  .node_name = "stn-ip6-punt",
  .runs_before = VNET_FEATURES("ip6-punt-redirect"),
};
/** *INDENT-ON* */

u8 *
format_stn_ip4_punt_trace (u8 * s, va_list * args)
{
  return format_stn_ip46_punt_trace (s, args, 1);
}

static uword
stn_ip4_punt_fn (vlib_main_t * vm,
	           vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  return stn_ip46_punt_fn(vm, node, frame, 1);
}

/** *INDENT-OFF* */
VLIB_REGISTER_NODE (stn_ip4_punt, static) =
{
  .function = stn_ip4_punt_fn,
  .name = "stn-ip4-punt",
  .vector_size = sizeof (u32),
  .format_trace = format_stn_ip4_punt_trace,
  .n_errors = STN_IP_PUNT_N_ERROR,
  .error_strings = stn_ip_punt_error_strings,
  .n_next_nodes = STN_IP_PUNT_N_NEXT,
  .next_nodes =
  {
      [STN_IP_PUNT_DROP] = "error-drop",
  },
};
VNET_FEATURE_INIT (stn_ip4_punt_feat_node, static) = {
  .arc_name = "ip4-punt",
  .node_name = "stn-ip4-punt",
  .runs_before = VNET_FEATURES("ip4-punt-redirect"),
};
/** *INDENT-ON* */

clib_error_t *
stn_init (vlib_main_t * vm)
{
  stn_main_t *stn = &stn_main;
  stn->rules = 0;
  clib_bihash_init_16_8(&stn->rule_by_address_table, "stn addresses",
			1024, 1<<20);

  clib_memcpy_fast(stn_ip4_ethernet_header.dst_address, stn_hw_addr_dst, 6);
  clib_memcpy_fast(stn_ip4_ethernet_header.src_address, stn_hw_addr_local, 6);
  stn_ip4_ethernet_header.type = clib_host_to_net_u16(ETHERNET_TYPE_IP4);

  clib_memcpy_fast(stn_ip6_ethernet_header.dst_address, stn_hw_addr_dst, 6);
  clib_memcpy_fast(stn_ip6_ethernet_header.src_address, stn_hw_addr_local, 6);
  stn_ip6_ethernet_header.type = clib_host_to_net_u16(ETHERNET_TYPE_IP6);

  return stn_api_init (vm, stn);

  return NULL;
}

VLIB_INIT_FUNCTION (stn_init);

/* *INDENT-OFF* */
VLIB_PLUGIN_REGISTER () = {
    .version = VPP_BUILD_VER,
    .description = "VPP Steals the NIC (STN) for Container Integration",
};
/* *INDENT-ON* */

int stn_rule_add_del (stn_rule_add_del_args_t *args)
{
  vnet_main_t *vnm = vnet_get_main();
  vlib_main_t *vm = vlib_get_main();
  stn_main_t *stn = &stn_main;

  stn_rule_t *r = NULL;
  clib_bihash_kv_16_8_t kv;
  kv.key[0] = args->address.as_u64[0];
  kv.key[1] = args->address.as_u64[1];

  if (clib_bihash_search_inline_16_8 (&stn->rule_by_address_table, &kv) == 0)
    {
      r = &stn->rules[kv.value];
    }
  else if (!args->del)
    {
      pool_get(stn->rules, r);
      kv.value = r - stn->rules;
      clib_bihash_add_del_16_8(&stn->rule_by_address_table, &kv, 1);
      r->address = args->address;

      stn->n_rules++;
      if (stn->n_rules == 1)
	{
            vnet_feature_enable_disable("ip6-punt", "stn-ip6-punt",
                                        0, 1, 0, 0);
            vnet_feature_enable_disable("ip4-punt", "stn-ip4-punt",
                                        0, 1, 0, 0);

	  udp_punt_unknown(vm, 0, 1);
	  udp_punt_unknown(vm, 1, 1);
	  tcp_punt_unknown(vm, 0, 1);
	  tcp_punt_unknown(vm, 1, 1);
	}
    }

  if (!args->del)
    {
      /* Getting output node and adding it as next */
      u32 output_node_index =
          vnet_tx_node_index_for_sw_interface(vnm, args->sw_if_index);
      u32 node_index = ip46_address_is_ip4(&args->address)?
          stn_ip4_punt.index : stn_ip6_punt.index;

      r->sw_if_index = args->sw_if_index;
      r->next_node_index =
	  vlib_node_add_next(vm, node_index, output_node_index);

      /* enabling forwarding on the output node (might not be done since
       * it is unnumbered) */
      ip4_sw_interface_enable_disable(args->sw_if_index, 1);
      ip6_sw_interface_enable_disable(args->sw_if_index, 1);
    }
  else if (r)
    {
      clib_bihash_add_del_16_8(&stn->rule_by_address_table, &kv, 0);
      pool_put(stn->rules, r);

      stn->n_rules--;
      if (stn->n_rules == 0)
	{
            vnet_feature_enable_disable("ip6-punt", "stn-ip6-punt",
                                        0, 0, 0, 0);
            vnet_feature_enable_disable("ip4-punt", "stn-ip4-punt",
                                        0, 0, 0, 0);
	}
    }
  else
    {
      return VNET_API_ERROR_NO_SUCH_ENTRY;
    }

  return 0;
}

static clib_error_t *
show_stn_rules_fn (vlib_main_t * vm,
		      unformat_input_t * input, vlib_cli_command_t * cmd)
{
  stn_main_t *stn = &stn_main;
  u8 *s = 0;
  stn_rule_t *rule;
  pool_foreach(rule, stn->rules, {
      s = format (s, "- %U\n", format_stn_rule, rule);
  });

  vlib_cli_output(vm, "%v", s);

  vec_free(s);
  return NULL;
}

VLIB_CLI_COMMAND (show_stn_rules_command, static) =
{
  .path = "show stn rules",
  .short_help = "",
  .function = show_stn_rules_fn,
};

static clib_error_t *
stn_rule_fn (vlib_main_t * vm,
		      unformat_input_t * input, vlib_cli_command_t * cmd)
{
  unformat_input_t _line_input, *line_input = &_line_input;
  clib_error_t *error = 0;
  stn_rule_add_del_args_t args = {};
  u8 got_addr = 0;
  u8 got_iface = 0;
  int ret;

  if (!unformat_user (input, unformat_line_input, line_input))
    return 0;

  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (line_input, "address %U", unformat_ip46_address,
		    &args.address, IP46_TYPE_ANY))
	got_addr = 1;
      else if (unformat
	       (line_input, "interface %U", unformat_vnet_sw_interface,
		vnet_get_main(), &args.sw_if_index))
	got_iface = 1;
      else if (unformat (line_input, "del"))
	args.del = 1;
      else
	{
	  error = clib_error_return (0, "parse error: '%U'",
				     format_unformat_error, line_input);
	  goto done;
	}
    }

  if (!got_addr)
    {
      error = clib_error_return (0, "Missing address");
      goto done;
    }

  if (!got_iface)
    {
      error = clib_error_return (0, "Missing interface");
      goto done;
    }

  if ((ret = stn_rule_add_del (&args)))
    {
      error = clib_error_return (0, "stn_rule_add_del returned error %d", ret);
      goto done;
    }

done:
  unformat_free (line_input);
  return error;
}

VLIB_CLI_COMMAND (stn_rule_command, static) =
{
  .path = "stn rule",
  .short_help = "address <addr> interface <iface> [del]",
  .function = stn_rule_fn,
};