text: /*
   * Copyright (c) 2018 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.
   */
  /**
   * @file
   * @brief NAT66 inside to outside network translation
   */
  
  #include <nat/nat66/nat66.h>
  #include <vnet/ip/ip6_to_ip4.h>
  #include <vnet/fib/fib_table.h>
  
  typedef struct
  {
    u32 sw_if_index;
    u32 next_index;
  } nat66_in2out_trace_t;
  
  static u8 *
  format_nat66_in2out_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 *);
    nat66_in2out_trace_t *t = va_arg (*args, nat66_in2out_trace_t *);
  
    s =
      format (s, "NAT66-in2out: sw_if_index %d, next index %d", t->sw_if_index,
  	    t->next_index);
  
    return s;
  }
  
  #define foreach_nat66_in2out_error                       \
  _(NO_TRANSLATION, "no translation")                      \
  _(UNKNOWN, "unknown")
  
  typedef enum
  {
  #define _(sym,str) NAT66_IN2OUT_ERROR_##sym,
    foreach_nat66_in2out_error
  #undef _
      NAT66_IN2OUT_N_ERROR,
  } nat66_in2out_error_t;
  
  static char *nat66_in2out_error_strings[] = {
  #define _(sym,string) string,
    foreach_nat66_in2out_error
  #undef _
  };
  
  typedef enum
  {
    NAT66_IN2OUT_NEXT_IP6_LOOKUP,
    NAT66_IN2OUT_NEXT_DROP,
    NAT66_IN2OUT_N_NEXT,
  } nat66_in2out_next_t;
  
  static inline u8
  nat66_not_translate (u32 rx_fib_index, ip6_address_t ip6_addr)
  {
    nat66_main_t *nm = &nat66_main;
    u32 sw_if_index;
    nat66_interface_t *i;
    fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
    fib_prefix_t pfx = {
      .fp_proto = FIB_PROTOCOL_IP6,
      .fp_len = 128,
      .fp_addr = {
  		.ip6 = ip6_addr,
  		},
    };
  
    fei = fib_table_lookup (rx_fib_index, &pfx);
    if (FIB_NODE_INDEX_INVALID == fei)
      return 1;
    sw_if_index = fib_entry_get_resolving_interface (fei);
  
    if (sw_if_index == ~0)
      {
        fei = fib_table_lookup (nm->outside_fib_index, &pfx);
        if (FIB_NODE_INDEX_INVALID == fei)
  	return 1;
        sw_if_index = fib_entry_get_resolving_interface (fei);
      }
  
    /* *INDENT-OFF* */
    pool_foreach (i, nm->interfaces)
     {
      /* NAT packet aimed at outside interface */
      if (nat66_interface_is_outside (i) && sw_if_index == i->sw_if_index)
        return 0;
    }
    /* *INDENT-ON* */
  
    return 1;
  }
  
  VLIB_NODE_FN (nat66_in2out_node) (vlib_main_t * vm,
  				  vlib_node_runtime_t * node,
  				  vlib_frame_t * frame)
  {
    u32 n_left_from, *from, *to_next;
    nat66_in2out_next_t next_index;
    u32 thread_index = vm->thread_index;
    nat66_main_t *nm = &nat66_main;
  
    from = vlib_frame_vector_args (frame);
    n_left_from = frame->n_vectors;
    next_index = node->cached_next_index;
  
    while (n_left_from > 0)
      {
        u32 n_left_to_next;
  
        vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
  
        while (n_left_from > 0 && n_left_to_next > 0)
  	{
  	  u32 bi0;
  	  vlib_buffer_t *b0;
  	  u32 next0 = NAT66_IN2OUT_NEXT_IP6_LOOKUP;
  	  ip6_header_t *ip60;
  	  u16 l4_offset0, frag_offset0;
  	  u8 l4_protocol0;
  	  nat66_static_mapping_t *sm0;
  	  u32 sw_if_index0, fib_index0;
  	  udp_header_t *udp0;
  	  tcp_header_t *tcp0;
  	  icmp46_header_t *icmp0;
  	  u16 *checksum0 = 0;
  	  ip_csum_t csum0;
  
  	  /* speculatively enqueue b0 to the current next frame */
  	  bi0 = from[0];
  	  to_next[0] = bi0;
  	  from += 1;
  	  to_next += 1;
  	  n_left_from -= 1;
  	  n_left_to_next -= 1;
  
  	  b0 = vlib_get_buffer (vm, bi0);
  	  ip60 = vlib_buffer_get_current (b0);
  
  	  if (PREDICT_FALSE
  	      (ip6_parse
  	       (vm, b0, ip60, b0->current_length, &l4_protocol0, &l4_offset0,
  		&frag_offset0)))
  	    {
  	      next0 = NAT66_IN2OUT_NEXT_DROP;
  	      b0->error = node->errors[NAT66_IN2OUT_ERROR_UNKNOWN];
  	      goto trace0;
  	    }
  
  	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
  	  fib_index0 =
  	    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6,
  						 sw_if_index0);
  
  	  if (nat66_not_translate (fib_index0, ip60->dst_address))
  	    goto trace0;
  
  	  sm0 = nat66_static_mapping_get (&ip60->src_address, fib_index0, 1);
  	  if (PREDICT_FALSE (!sm0))
  	    {
  	      goto trace0;
  	    }
  
  	  if (l4_protocol0 == IP_PROTOCOL_UDP)
  	    {
  	      udp0 = (udp_header_t *) u8_ptr_add (ip60, l4_offset0);
  	      checksum0 = &udp0->checksum;
  	    }
  	  else if (l4_protocol0 == IP_PROTOCOL_TCP)
  	    {
  	      tcp0 = (tcp_header_t *) u8_ptr_add (ip60, l4_offset0);
  	      checksum0 = &tcp0->checksum;
  	    }
  	  else if (l4_protocol0 == IP_PROTOCOL_ICMP6)
  	    {
  	      icmp0 = (icmp46_header_t *) u8_ptr_add (ip60, l4_offset0);
  	      checksum0 = &icmp0->checksum;
  	    }
  	  else
  	    goto skip_csum0;
  
  	  csum0 = ip_csum_sub_even (*checksum0, ip60->src_address.as_u64[0]);
  	  csum0 = ip_csum_sub_even (csum0, ip60->src_address.as_u64[1]);
  	  csum0 = ip_csum_add_even (csum0, sm0->e_addr.as_u64[0]);
  	  csum0 = ip_csum_add_even (csum0, sm0->e_addr.as_u64[1]);
  	  *checksum0 = ip_csum_fold (csum0);
  
  	skip_csum0:
  	  ip60->src_address.as_u64[0] = sm0->e_addr.as_u64[0];
  	  ip60->src_address.as_u64[1] = sm0->e_addr.as_u64[1];
  
  	  vlib_increment_combined_counter (&nm->session_counters,
  					   thread_index, sm0 - nm->sm, 1,
  					   vlib_buffer_length_in_chain (vm,
  									b0));
  
  	trace0:
  	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
  			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
  	    {
  	      nat66_in2out_trace_t *t =
  		vlib_add_trace (vm, node, b0, sizeof (*t));
  	      t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
  	      t->next_index = next0;
  	    }
  
  	  if (next0 != NAT66_IN2OUT_NEXT_DROP)
  	    {
  	      vlib_increment_simple_counter (&nm->in2out_packets,
  					     thread_index, sw_if_index0, 1);
  	    }
  
  	  /* verify speculative enqueue, maybe switch current next frame */
  	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
  					   n_left_to_next, bi0, next0);
  	}
        vlib_put_next_frame (vm, node, next_index, n_left_to_next);
      }
  
    return frame->n_vectors;
  }
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (nat66_in2out_node) = {
    .name = "nat66-in2out",
    .vector_size = sizeof (u32),
    .format_trace = format_nat66_in2out_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
    .n_errors = ARRAY_LEN (nat66_in2out_error_strings),
    .error_strings = nat66_in2out_error_strings,
    .n_next_nodes = NAT66_IN2OUT_N_NEXT,
    /* edit / add dispositions here */
    .next_nodes = {
      [NAT66_IN2OUT_NEXT_DROP] = "error-drop",
      [NAT66_IN2OUT_NEXT_IP6_LOOKUP] = "ip6-lookup",
    },
  };
  /* *INDENT-ON* */
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  