/*
 * 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.
 */
/*
 * ip/ip4_source_check.c: IP v4 check source address (unicast RPF check)
 *
 * Copyright (c) 2008 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 TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef __URPF_DP_H__
#define __URPF_DP_H__

#include <vnet/fib/ip4_fib.h>
#include <vnet/fib/ip6_fib.h>
#include <vnet/fib/fib_urpf_list.h>
#include <vnet/dpo/load_balance.h>

#include <urpf/urpf.h>

/**
 * @file
 * @brief Unicast Reverse Path forwarding.
 *
 * This file contains the interface unicast source check.
 */

#define foreach_urpf_error                 \
  _(DROP, "uRPF Drop")                     \

typedef enum urpf_error_t_
{
#define _(a,b) URPF_ERROR_##a,
  foreach_urpf_error
#undef _
    URPF_N_ERROR,
} urpf_error_t;

typedef enum
{
  URPF_NEXT_DROP,
  URPF_N_NEXT,
} urpf_next_t;

static_always_inline u32
urpf_get_fib_index (vlib_buffer_t *b, ip_address_family_t af, vlib_dir_t dir)
{
  u32 sw_if_index = vnet_buffer (b)->sw_if_index[dir];
  return vec_elt (urpf_cfgs[af][dir], sw_if_index).fib_index;
}

static_always_inline void
urpf_perform_check_x1 (ip_address_family_t af, vlib_dir_t dir,
		       urpf_mode_t mode, vlib_buffer_t *b, const u8 *h,
		       u32 fib_index, load_balance_t **lb, u32 *pass)
{
  load_balance_t *llb;
  u32 lpass;
  u32 lb_index;

  ASSERT (fib_index != ~0);

  if (AF_IP4 == af)
    {
      const ip4_header_t *ip;

      ip = (ip4_header_t *) h;

      lb_index = ip4_fib_forwarding_lookup (fib_index, &ip->src_address);

      /* Pass multicast. */
      lpass = (ip4_address_is_multicast (&ip->src_address) ||
	       ip4_address_is_global_broadcast (&ip->src_address));
    }
  else
    {
      const ip6_header_t *ip;

      ip = (ip6_header_t *) h;

      lb_index = ip6_fib_table_fwding_lookup (fib_index, &ip->src_address);
      lpass = ip6_address_is_multicast (&ip->src_address);
    }

  llb = load_balance_get (lb_index);

  if (URPF_MODE_STRICT == mode)
    {
      int res;

      res = fib_urpf_check (llb->lb_urpf, vnet_buffer (b)->sw_if_index[dir]);
      if (VLIB_RX == dir)
	lpass |= res;
      else
	{
	  lpass |= !res && fib_urpf_check_size (llb->lb_urpf);
	  lpass |= b->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED;
	}
    }
  else
    lpass |= fib_urpf_check_size (llb->lb_urpf);

  *lb = llb;
  *pass = lpass;
}

static_always_inline void
urpf_perform_check_x2 (ip_address_family_t af, vlib_dir_t dir,
		       urpf_mode_t mode, vlib_buffer_t *b0, vlib_buffer_t *b1,
		       const u8 *h0, const u8 *h1, u32 fib_index0,
		       u32 fib_index1, load_balance_t **lb0,
		       load_balance_t **lb1, u32 *pass0, u32 *pass1)
{
  load_balance_t *llb0, *llb1;
  u32 lpass0, lpass1;
  u32 lb_index0, lb_index1;

  ASSERT (fib_index0 != ~0);
  ASSERT (fib_index1 != ~0);

  if (AF_IP4 == af)
    {
      const ip4_header_t *ip0, *ip1;

      ip0 = (ip4_header_t *) h0;
      ip1 = (ip4_header_t *) h1;

      ip4_fib_forwarding_lookup_x2 (fib_index0, fib_index1, &ip0->src_address,
				    &ip1->src_address, &lb_index0, &lb_index1);
      /* Pass multicast. */
      lpass0 = (ip4_address_is_multicast (&ip0->src_address) ||
		ip4_address_is_global_broadcast (&ip0->src_address));
      lpass1 = (ip4_address_is_multicast (&ip1->src_address) ||
		ip4_address_is_global_broadcast (&ip1->src_address));
    }
  else
    {
      const ip6_header_t *ip0, *ip1;

      ip0 = (ip6_header_t *) h0;
      ip1 = (ip6_header_t *) h1;

      lb_index0 = ip6_fib_table_fwding_lookup (fib_index0, &ip0->src_address);
      lb_index1 = ip6_fib_table_fwding_lookup (fib_index1, &ip1->src_address);
      lpass0 = ip6_address_is_multicast (&ip0->src_address);
      lpass1 = ip6_address_is_multicast (&ip1->src_address);
    }

  llb0 = load_balance_get (lb_index0);
  llb1 = load_balance_get (lb_index1);

  if (URPF_MODE_STRICT == mode)
    {
      /* for RX the check is: would this source adddress be
       * forwarded out of the interface on which it was recieved,
       * if yes allow. For TX it's; would this source address be
       * forwarded out of the interface through which it is being
       * sent, if yes drop.
       */
      int res0, res1;

      res0 =
	fib_urpf_check (llb0->lb_urpf, vnet_buffer (b0)->sw_if_index[dir]);
      res1 =
	fib_urpf_check (llb1->lb_urpf, vnet_buffer (b1)->sw_if_index[dir]);

      if (VLIB_RX == dir)
	{
	  lpass0 |= res0;
	  lpass1 |= res1;
	}
      else
	{
	  lpass0 |= !res0 && fib_urpf_check_size (llb0->lb_urpf);
	  lpass1 |= !res1 && fib_urpf_check_size (llb1->lb_urpf);

	  /* allow locally generated */
	  lpass0 |= b0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED;
	  lpass1 |= b1->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED;
	}
    }
  else
    {
      lpass0 |= fib_urpf_check_size (llb0->lb_urpf);
      lpass1 |= fib_urpf_check_size (llb1->lb_urpf);
    }

  *lb0 = llb0;
  *lb1 = llb1;
  *pass0 = lpass0;
  *pass1 = lpass1;
}

static_always_inline uword
urpf_inline (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame,
	     ip_address_family_t af, vlib_dir_t dir, urpf_mode_t mode)
{
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
  u16 nexts[VLIB_FRAME_SIZE], *next;
  u32 n_left, *from;

  from = vlib_frame_vector_args (frame);
  n_left = frame->n_vectors;
  b = bufs;
  next = nexts;

  vlib_get_buffers (vm, from, bufs, n_left);

  while (n_left >= 4)
    {
      u32 pass0, pass1;
      load_balance_t *lb0 = 0, *lb1 = 0;
      u32 fib_index0, fib_index1;
      const u8 *h0, *h1;

      /* Prefetch next iteration. */
      {
	vlib_prefetch_buffer_header (b[2], LOAD);
	vlib_prefetch_buffer_header (b[3], LOAD);
	vlib_prefetch_buffer_data (b[2], LOAD);
	vlib_prefetch_buffer_data (b[3], LOAD);
      }

      h0 = (u8 *) vlib_buffer_get_current (b[0]);
      h1 = (u8 *) vlib_buffer_get_current (b[1]);
      if (VLIB_TX == dir)
	{
	  h0 += vnet_buffer (b[0])->ip.save_rewrite_length;
	  h1 += vnet_buffer (b[1])->ip.save_rewrite_length;
	}

      fib_index0 = urpf_get_fib_index (b[0], af, dir);
      fib_index1 = urpf_get_fib_index (b[1], af, dir);
      urpf_perform_check_x2 (af, dir, mode, b[0], b[1], h0, h1, fib_index0,
			     fib_index1, &lb0, &lb1, &pass0, &pass1);

      if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
	{
	  urpf_trace_t *t;

	  t = vlib_add_trace (vm, node, b[0], sizeof (*t));
	  t->urpf = lb0 ? lb0->lb_urpf : ~0;
	  t->fib_index = fib_index0;
	}
      if (b[1]->flags & VLIB_BUFFER_IS_TRACED)
	{
	  urpf_trace_t *t;

	  t = vlib_add_trace (vm, node, b[1], sizeof (*t));
	  t->urpf = lb1 ? lb1->lb_urpf : ~0;
	  t->fib_index = fib_index1;
	}

      if (PREDICT_TRUE (pass0))
	vnet_feature_next_u16 (&next[0], b[0]);
      else
	{
	  next[0] = URPF_NEXT_DROP;
	  b[0]->error = node->errors[URPF_ERROR_DROP];
	}
      if (PREDICT_TRUE (pass1))
	vnet_feature_next_u16 (&next[1], b[1]);
      else
	{
	  next[1] = URPF_NEXT_DROP;
	  b[1]->error = node->errors[URPF_ERROR_DROP];
	}
      b += 2;
      next += 2;
      n_left -= 2;
    }

  while (n_left)
    {
      u32 pass0, fib_index0;
      load_balance_t *lb0 = 0;
      const u8 *h0;

      h0 = (u8 *) vlib_buffer_get_current (b[0]);

      if (VLIB_TX == dir)
	h0 += vnet_buffer (b[0])->ip.save_rewrite_length;

      fib_index0 = urpf_get_fib_index (b[0], af, dir);
      urpf_perform_check_x1 (af, dir, mode, b[0], h0, fib_index0, &lb0,
			     &pass0);

      if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
	{
	  urpf_trace_t *t;

	  t = vlib_add_trace (vm, node, b[0], sizeof (*t));
	  t->urpf = lb0 ? lb0->lb_urpf : ~0;
	  t->fib_index = fib_index0;
	}

      if (PREDICT_TRUE (pass0))
	vnet_feature_next_u16 (&next[0], b[0]);
      else
	{
	  next[0] = URPF_NEXT_DROP;
	  b[0]->error = node->errors[URPF_ERROR_DROP];
	}
      b++;
      next++;
      n_left--;
    }

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

  return frame->n_vectors;
}

#endif

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