/*
 * 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.h: ip4 main include file
 *
 * 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 included_ip_ip4_h
#define included_ip_ip4_h

#include <vnet/ip/ip4_mtrie.h>
#include <vnet/ip/ip4_packet.h>
#include <vnet/ip/lookup.h>
#include <vnet/feature/feature.h>

typedef struct ip4_fib_t {
  /* Hash table for each prefix length mapping. */
  uword * fib_entry_by_dst_address[33];

  /* Mtrie for fast lookups.  Hash is used to maintain overlapping prefixes. */
  ip4_fib_mtrie_t mtrie;

  /* Table ID (hash key) for this FIB. */
  u32 table_id;

  /* Index into FIB vector. */
  u32 index;

  /* flow hash configuration */
  flow_hash_config_t flow_hash_config;

  /* N-tuple classifier indices */
  u32 fwd_classify_table_index;
  u32 rev_classify_table_index;

} ip4_fib_t;

struct ip4_main_t;

typedef void (ip4_add_del_interface_address_function_t)
  (struct ip4_main_t * im,
   uword opaque,
   u32 sw_if_index,
   ip4_address_t * address,
   u32 address_length,
   u32 if_address_index,
   u32 is_del);

typedef struct {
  ip4_add_del_interface_address_function_t * function;
  uword function_opaque;
} ip4_add_del_interface_address_callback_t;

/**
 * @brief IPv4 main type.
 *
 * State of IPv4 VPP processing including:
 * - FIBs
 * - Feature indices used in feature topological sort
 * - Feature node run time references
 */

typedef struct ip4_main_t {
  ip_lookup_main_t lookup_main;

  /** Vector of FIBs. */
  struct fib_table_t_ * fibs;

  u32 fib_masks[33];

  /** Table index indexed by software interface. */
  u32 * fib_index_by_sw_if_index;

  /* IP4 enabled count by software interface */
  u8 * ip_enabled_by_sw_if_index;

  /** Hash table mapping table id to fib index.
     ID space is not necessarily dense; index space is dense. */
  uword * fib_index_by_table_id;

  /** Functions to call when interface address changes. */
  ip4_add_del_interface_address_callback_t * add_del_interface_address_callbacks;

  /** Template used to generate IP4 ARP packets. */
  vlib_packet_template_t ip4_arp_request_packet_template;

  /** Seed for Jenkins hash used to compute ip4 flow hash. */
  u32 flow_hash_seed;

  /** @brief Template information for VPP generated packets */
  struct {
    /** TTL to use for host generated packets. */
    u8 ttl;

    /** TOS byte to use for host generated packets. */
    u8 tos;

    u8 pad[2];
  } host_config;
} ip4_main_t;

/** Global ip4 main structure. */
extern ip4_main_t ip4_main;

/** Global ip4 input node.  Errors get attached to ip4 input node. */
extern vlib_node_registration_t ip4_input_node;
extern vlib_node_registration_t ip4_lookup_node;
extern vlib_node_registration_t ip4_rewrite_node;
extern vlib_node_registration_t ip4_rewrite_local_node;
extern vlib_node_registration_t ip4_arp_node;
extern vlib_node_registration_t ip4_glean_node;
extern vlib_node_registration_t ip4_midchain_node;

always_inline uword
ip4_destination_matches_route (const ip4_main_t * im,
			       const ip4_address_t * key,
			       const ip4_address_t * dest,
			       uword dest_length)
{ return 0 == ((key->data_u32 ^ dest->data_u32) & im->fib_masks[dest_length]); }

always_inline uword
ip4_destination_matches_interface (ip4_main_t * im,
				   ip4_address_t * key,
				   ip_interface_address_t * ia)
{
  ip4_address_t * a = ip_interface_address_get_address (&im->lookup_main, ia);
  return ip4_destination_matches_route (im, key, a, ia->address_length);
}

/* As above but allows for unaligned destinations (e.g. works right from IP header of packet). */
always_inline uword
ip4_unaligned_destination_matches_route (ip4_main_t * im,
					 ip4_address_t * key,
					 ip4_address_t * dest,
					 uword dest_length)
{ return 0 == ((clib_mem_unaligned (&key->data_u32, u32) ^ dest->data_u32) & im->fib_masks[dest_length]); }

always_inline int
ip4_src_address_for_packet (ip_lookup_main_t * lm,
			    u32 sw_if_index,
			    ip4_address_t * src)
{
    u32 if_add_index =
	lm->if_address_pool_index_by_sw_if_index[sw_if_index];
    if (PREDICT_TRUE(if_add_index != ~0)) {
	ip_interface_address_t *if_add =
	    pool_elt_at_index(lm->if_address_pool, if_add_index);
	ip4_address_t *if_ip =
	    ip_interface_address_get_address(lm, if_add);
	*src = *if_ip;
	return 0;
    }
    else
    {
	ASSERT(0);
	src->as_u32 = 0;
    }
    return (!0);
}

/* Find interface address which matches destination. */
always_inline ip4_address_t *
ip4_interface_address_matching_destination (ip4_main_t * im, ip4_address_t * dst, u32 sw_if_index,
					    ip_interface_address_t ** result_ia)
{
  ip_lookup_main_t * lm = &im->lookup_main;
  ip_interface_address_t * ia;
  ip4_address_t * result = 0;

  foreach_ip_interface_address (lm, ia, sw_if_index,
                                1 /* honor unnumbered */,
  ({
    ip4_address_t * a = ip_interface_address_get_address (lm, ia);
    if (ip4_destination_matches_route (im, dst, a, ia->address_length))
      {
	result = a;
	break;
      }
  }));
  if (result_ia)
    *result_ia = result ? ia : 0;
  return result;
}

ip4_address_t *
ip4_interface_first_address (ip4_main_t * im, u32 sw_if_index,
                             ip_interface_address_t ** result_ia);

clib_error_t *
ip4_add_del_interface_address (vlib_main_t * vm, u32 sw_if_index,
			       ip4_address_t * address, u32 address_length,
			       u32 is_del);

void
ip4_sw_interface_enable_disable (u32 sw_if_index,
				 u32 is_enable);

int ip4_address_compare (ip4_address_t * a1, ip4_address_t * a2);

/* Send an ARP request to see if given destination is reachable on given interface. */
clib_error_t *
ip4_probe_neighbor (vlib_main_t * vm, ip4_address_t * dst, u32 sw_if_index);

clib_error_t *
ip4_set_arp_limit (u32 arp_limit);

uword
ip4_udp_register_listener (vlib_main_t * vm,
			   u16 dst_port,
			   u32 next_node_index);

void
ip4_icmp_register_type (vlib_main_t * vm, icmp4_type_t type,
                        u32 node_index);

u16 ip4_tcp_udp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0, ip4_header_t * ip0);

void ip4_register_protocol (u32 protocol, u32 node_index);

serialize_function_t serialize_vnet_ip4_main, unserialize_vnet_ip4_main;

int vnet_set_ip4_flow_hash (u32 table_id, flow_hash_config_t flow_hash_config);

void ip4_mtrie_init (ip4_fib_mtrie_t * m);

int vnet_set_ip4_classify_intfc (vlib_main_t * vm, u32 sw_if_index,
                                 u32 table_index);

/* Compute flow hash.  We'll use it to select which adjacency to use for this
   flow.  And other things. */
always_inline u32
ip4_compute_flow_hash (const ip4_header_t * ip,
		       flow_hash_config_t flow_hash_config)
{
    tcp_header_t * tcp = (void *) (ip + 1);
    u32 a, b, c, t1, t2;
    uword is_tcp_udp = (ip->protocol == IP_PROTOCOL_TCP
			|| ip->protocol == IP_PROTOCOL_UDP);

    t1 = (flow_hash_config & IP_FLOW_HASH_SRC_ADDR)
        ? ip->src_address.data_u32 : 0;
    t2 = (flow_hash_config & IP_FLOW_HASH_DST_ADDR)
        ? ip->dst_address.data_u32 : 0;

    a = (flow_hash_config & IP_FLOW_HASH_REVERSE_SRC_DST) ? t2 : t1;
    b = (flow_hash_config & IP_FLOW_HASH_REVERSE_SRC_DST) ? t1 : t2;
    b ^= (flow_hash_config & IP_FLOW_HASH_PROTO) ? ip->protocol : 0;

    t1 = is_tcp_udp ? tcp->ports.src : 0;
    t2 = is_tcp_udp ? tcp->ports.dst : 0;

    t1 = (flow_hash_config & IP_FLOW_HASH_SRC_PORT) ? t1 : 0;
    t2 = (flow_hash_config & IP_FLOW_HASH_DST_PORT) ? t2 : 0;

    c = (flow_hash_config & IP_FLOW_HASH_REVERSE_SRC_DST) ?
        (t1<<16) | t2 : (t2<<16) | t1;

    hash_v3_mix32 (a, b, c);
    hash_v3_finalize32 (a, b, c);

    return c;
}

void
ip4_forward_next_trace (vlib_main_t * vm,
                        vlib_node_runtime_t * node,
                        vlib_frame_t * frame,
                        vlib_rx_or_tx_t which_adj_index);

u8 * format_ip4_forward_next_trace (u8 * s, va_list * args);

u32 ip4_tcp_udp_validate_checksum (vlib_main_t * vm, vlib_buffer_t * p0);

#endif /* included_ip_ip4_h */