text: /*
   * 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 <nat/dslite/dslite.h>
  #include <nat/nat_syslog.h>
  
  typedef enum
  {
    DSLITE_IN2OUT_NEXT_IP4_LOOKUP,
    DSLITE_IN2OUT_NEXT_IP6_ICMP,
    DSLITE_IN2OUT_NEXT_DROP,
    DSLITE_IN2OUT_NEXT_SLOWPATH,
    DSLITE_IN2OUT_N_NEXT,
  } dslite_in2out_next_t;
  
  static char *dslite_in2out_error_strings[] = {
  #define _(sym,string) string,
    foreach_dslite_error
  #undef _
  };
  
  static u32
  slow_path (dslite_main_t * dm, dslite_session_key_t * in2out_key,
  	   dslite_session_t ** sp, u32 next, u8 * error, u32 thread_index)
  {
    dslite_b4_t *b4;
    clib_bihash_kv_16_8_t b4_kv, b4_value;
    clib_bihash_kv_24_8_t in2out_kv;
    clib_bihash_kv_8_8_t out2in_kv;
    dlist_elt_t *head_elt, *oldest_elt, *elt;
    u32 oldest_index;
    dslite_session_t *s;
    nat_session_key_t out2in_key;
    nat_ip4_addr_port_t addr_port;
    u32 b4_index;
  
    out2in_key.protocol = in2out_key->proto;
    out2in_key.fib_index = 0;
  
    b4_kv.key[0] = in2out_key->softwire_id.as_u64[0];
    b4_kv.key[1] = in2out_key->softwire_id.as_u64[1];
  
    if (clib_bihash_search_16_8
        (&dm->per_thread_data[thread_index].b4_hash, &b4_kv, &b4_value))
      {
        pool_get (dm->per_thread_data[thread_index].b4s, b4);
        clib_memset (b4, 0, sizeof (*b4));
        b4->addr.as_u64[0] = in2out_key->softwire_id.as_u64[0];
        b4->addr.as_u64[1] = in2out_key->softwire_id.as_u64[1];
  
        pool_get (dm->per_thread_data[thread_index].list_pool, head_elt);
        b4->sessions_per_b4_list_head_index =
  	head_elt - dm->per_thread_data[thread_index].list_pool;
        clib_dlist_init (dm->per_thread_data[thread_index].list_pool,
  		       b4->sessions_per_b4_list_head_index);
  
        b4_index = b4_kv.value = b4 - dm->per_thread_data[thread_index].b4s;
        clib_bihash_add_del_16_8 (&dm->per_thread_data[thread_index].b4_hash,
  				&b4_kv, 1);
  
        vlib_set_simple_counter (&dm->total_b4s, thread_index, 0,
  			       pool_elts (dm->
  					  per_thread_data[thread_index].b4s));
      }
    else
      {
        b4_index = b4_value.value;
        b4 =
  	pool_elt_at_index (dm->per_thread_data[thread_index].b4s,
  			   b4_value.value);
      }
  
    //TODO configurable quota
    if (b4->nsessions >= 1000)
      {
        oldest_index =
  	clib_dlist_remove_head (dm->per_thread_data[thread_index].list_pool,
  				b4->sessions_per_b4_list_head_index);
        ASSERT (oldest_index != ~0);
        clib_dlist_addtail (dm->per_thread_data[thread_index].list_pool,
  			  b4->sessions_per_b4_list_head_index, oldest_index);
        oldest_elt =
  	pool_elt_at_index (dm->per_thread_data[thread_index].list_pool,
  			   oldest_index);
        s =
  	pool_elt_at_index (dm->per_thread_data[thread_index].sessions,
  			   oldest_elt->value);
  
        in2out_kv.key[0] = s->in2out.as_u64[0];
        in2out_kv.key[1] = s->in2out.as_u64[1];
        in2out_kv.key[2] = s->in2out.as_u64[2];
        clib_bihash_add_del_24_8 (&dm->per_thread_data[thread_index].in2out,
  				&in2out_kv, 0);
        out2in_kv.key = s->out2in.as_u64;
        clib_bihash_add_del_8_8 (&dm->per_thread_data[thread_index].out2in,
  			       &out2in_kv, 0);
  
        addr_port.addr.as_u32 = s->out2in.addr.as_u32;
        addr_port.port = s->out2in.port;
  
        nat_free_ip4_addr_and_port (&dm->pool, thread_index,
  				  s->out2in.protocol, &addr_port);
  
        nat_syslog_dslite_apmdel (b4_index, &s->in2out.softwire_id,
  				&s->in2out.addr, s->in2out.port,
  				&s->out2in.addr, s->out2in.port,
  				s->in2out.proto);
  
        if (nat_alloc_ip4_addr_and_port
  	  (&dm->pool, 0, thread_index, thread_index,
  	   dm->port_per_thread, out2in_key.protocol, &addr_port))
  	ASSERT (0);
  
        out2in_key.addr.as_u32 = addr_port.addr.as_u32;
        out2in_key.port = addr_port.port;
      }
    else
      {
        if (nat_alloc_ip4_addr_and_port
  	  (&dm->pool, 0, thread_index, thread_index,
  	   dm->port_per_thread, out2in_key.protocol, &addr_port))
  	{
  	  *error = DSLITE_ERROR_OUT_OF_PORTS;
  	  return DSLITE_IN2OUT_NEXT_DROP;
  	}
  
        out2in_key.addr.as_u32 = addr_port.addr.as_u32;
        out2in_key.port = addr_port.port;
  
        pool_get (dm->per_thread_data[thread_index].sessions, s);
        clib_memset (s, 0, sizeof (*s));
        b4->nsessions++;
  
        pool_get (dm->per_thread_data[thread_index].list_pool, elt);
        clib_dlist_init (dm->per_thread_data[thread_index].list_pool,
  		       elt - dm->per_thread_data[thread_index].list_pool);
        elt->value = s - dm->per_thread_data[thread_index].sessions;
        s->per_b4_index = elt - dm->per_thread_data[thread_index].list_pool;
        s->per_b4_list_head_index = b4->sessions_per_b4_list_head_index;
        clib_dlist_addtail (dm->per_thread_data[thread_index].list_pool,
  			  s->per_b4_list_head_index,
  			  elt - dm->per_thread_data[thread_index].list_pool);
  
        vlib_set_simple_counter (&dm->total_sessions, thread_index, 0,
  			       pool_elts (dm->per_thread_data
  					  [thread_index].sessions));
      }
  
    s->in2out = *in2out_key;
    s->out2in = out2in_key;
    *sp = s;
    in2out_kv.key[0] = s->in2out.as_u64[0];
    in2out_kv.key[1] = s->in2out.as_u64[1];
    in2out_kv.key[2] = s->in2out.as_u64[2];
    in2out_kv.value = s - dm->per_thread_data[thread_index].sessions;
    clib_bihash_add_del_24_8 (&dm->per_thread_data[thread_index].in2out,
  			    &in2out_kv, 1);
    out2in_kv.key = s->out2in.as_u64;
    out2in_kv.value = s - dm->per_thread_data[thread_index].sessions;
    clib_bihash_add_del_8_8 (&dm->per_thread_data[thread_index].out2in,
  			   &out2in_kv, 1);
  
    nat_syslog_dslite_apmadd (b4_index, &s->in2out.softwire_id, &s->in2out.addr,
  			    s->in2out.port, &s->out2in.addr, s->out2in.port,
  			    s->in2out.proto);
  
    return next;
  }
  
  static inline u32
  dslite_icmp_in2out (dslite_main_t * dm, ip6_header_t * ip6,
  		    ip4_header_t * ip4, dslite_session_t ** sp, u32 next,
  		    u8 * error, u32 thread_index)
  {
    dslite_session_t *s = 0;
    icmp46_header_t *icmp = ip4_next_header (ip4);
    clib_bihash_kv_24_8_t kv, value;
    dslite_session_key_t key;
    u32 n = next;
    echo_header_t *echo;
    u32 new_addr, old_addr;
    u16 old_id, new_id;
    ip_csum_t sum;
  
    if (icmp_type_is_error_message (icmp->type))
      {
        n = DSLITE_IN2OUT_NEXT_DROP;
        *error = DSLITE_ERROR_BAD_ICMP_TYPE;
        goto done;
      }
  
    echo = (echo_header_t *) (icmp + 1);
  
    key.addr = ip4->src_address;
    key.port = echo->identifier;
    key.proto = NAT_PROTOCOL_ICMP;
    key.softwire_id.as_u64[0] = ip6->src_address.as_u64[0];
    key.softwire_id.as_u64[1] = ip6->src_address.as_u64[1];
    key.pad = 0;
    kv.key[0] = key.as_u64[0];
    kv.key[1] = key.as_u64[1];
    kv.key[2] = key.as_u64[2];
  
    if (clib_bihash_search_24_8
        (&dm->per_thread_data[thread_index].in2out, &kv, &value))
      {
        n = slow_path (dm, &key, &s, next, error, thread_index);
        if (PREDICT_FALSE (next == DSLITE_IN2OUT_NEXT_DROP))
  	goto done;
      }
    else
      {
        s =
  	pool_elt_at_index (dm->per_thread_data[thread_index].sessions,
  			   value.value);
      }
  
    old_addr = ip4->src_address.as_u32;
    ip4->src_address = s->out2in.addr;
    new_addr = ip4->src_address.as_u32;
    sum = ip4->checksum;
    sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, src_address);
    ip4->checksum = ip_csum_fold (sum);
  
    old_id = echo->identifier;
    echo->identifier = new_id = s->out2in.port;
    sum = icmp->checksum;
    sum = ip_csum_update (sum, old_id, new_id, echo_header_t, identifier);
    icmp->checksum = ip_csum_fold (sum);
  
  done:
    *sp = s;
    return n;
  }
  
  static inline uword
  dslite_in2out_node_fn_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
  			      vlib_frame_t * frame, u8 is_slow_path)
  {
    u32 n_left_from, *from, *to_next;
    dslite_in2out_next_t next_index;
    u32 node_index;
    vlib_node_runtime_t *error_node;
    u32 thread_index = vm->thread_index;
    f64 now = vlib_time_now (vm);
    dslite_main_t *dm = &dslite_main;
  
    node_index =
      is_slow_path ? dm->dslite_in2out_slowpath_node_index :
      dm->dslite_in2out_node_index;
  
    error_node = vlib_node_get_runtime (vm, node_index);
  
    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 = DSLITE_IN2OUT_NEXT_IP4_LOOKUP;
  	  ip4_header_t *ip40;
  	  ip6_header_t *ip60;
  	  u8 error0 = DSLITE_ERROR_IN2OUT;
  	  u32 proto0;
  	  dslite_session_t *s0 = 0;
  	  clib_bihash_kv_24_8_t kv0, value0;
  	  dslite_session_key_t key0;
  	  udp_header_t *udp0;
  	  tcp_header_t *tcp0;
  	  ip_csum_t sum0;
  	  u32 new_addr0, old_addr0;
  	  u16 old_port0, new_port0;
  
  	  /* 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 (ip60->protocol != IP_PROTOCOL_IP_IN_IP))
  	    {
  	      if (ip60->protocol == IP_PROTOCOL_ICMP6)
  		{
  		  next0 = DSLITE_IN2OUT_NEXT_IP6_ICMP;
  		  goto trace0;
  		}
  	      error0 = DSLITE_ERROR_BAD_IP6_PROTOCOL;
  	      next0 = DSLITE_IN2OUT_NEXT_DROP;
  	      goto trace0;
  	    }
  
  	  ip40 = vlib_buffer_get_current (b0) + sizeof (ip6_header_t);
  	  proto0 = ip_proto_to_nat_proto (ip40->protocol);
  
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
  	    {
  	      error0 = DSLITE_ERROR_UNSUPPORTED_PROTOCOL;
  	      next0 = DSLITE_IN2OUT_NEXT_DROP;
  	      goto trace0;
  	    }
  
  	  udp0 = ip4_next_header (ip40);
  	  tcp0 = (tcp_header_t *) udp0;
  
  	  if (is_slow_path)
  	    {
  	      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
  		{
  		  next0 =
  		    dslite_icmp_in2out (dm, ip60, ip40, &s0, next0, &error0,
  					thread_index);
  		  if (PREDICT_FALSE (next0 == DSLITE_IN2OUT_NEXT_DROP))
  		    goto trace0;
  
  		  goto accounting0;
  		}
  	    }
  	  else
  	    {
  	      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
  		{
  		  next0 = DSLITE_IN2OUT_NEXT_SLOWPATH;
  		  goto trace0;
  		}
  	    }
  
  	  key0.addr = ip40->src_address;
  	  key0.port = udp0->src_port;
  	  key0.proto = proto0;
  	  key0.softwire_id.as_u64[0] = ip60->src_address.as_u64[0];
  	  key0.softwire_id.as_u64[1] = ip60->src_address.as_u64[1];
  	  key0.pad = 0;
  	  kv0.key[0] = key0.as_u64[0];
  	  kv0.key[1] = key0.as_u64[1];
  	  kv0.key[2] = key0.as_u64[2];
  
  	  if (clib_bihash_search_24_8
  	      (&dm->per_thread_data[thread_index].in2out, &kv0, &value0))
  	    {
  	      if (is_slow_path)
  		{
  		  next0 =
  		    slow_path (dm, &key0, &s0, next0, &error0, thread_index);
  		  if (PREDICT_FALSE (next0 == DSLITE_IN2OUT_NEXT_DROP))
  		    goto trace0;
  		}
  	      else
  		{
  		  next0 = DSLITE_IN2OUT_NEXT_SLOWPATH;
  		  goto trace0;
  		}
  	    }
  	  else
  	    {
  	      s0 =
  		pool_elt_at_index (dm->per_thread_data[thread_index].sessions,
  				   value0.value);
  	    }
  
  	  old_addr0 = ip40->src_address.as_u32;
  	  ip40->src_address = s0->out2in.addr;
  	  new_addr0 = ip40->src_address.as_u32;
  	  sum0 = ip40->checksum;
  	  sum0 =
  	    ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
  			    src_address);
  	  ip40->checksum = ip_csum_fold (sum0);
  	  if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
  	    {
  	      old_port0 = tcp0->src_port;
  	      tcp0->src_port = s0->out2in.port;
  	      new_port0 = tcp0->src_port;
  
  	      sum0 = tcp0->checksum;
  	      sum0 =
  		ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
  				dst_address);
  	      sum0 =
  		ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
  				length);
  	      //mss_clamping (&dslite_main, tcp0, &sum0);
  	      tcp0->checksum = ip_csum_fold (sum0);
  	    }
  	  else
  	    {
  	      old_port0 = udp0->src_port;
  	      udp0->src_port = s0->out2in.port;
  	      udp0->checksum = 0;
  	    }
  
  	accounting0:
  	  /* Accounting */
  	  s0->last_heard = now;
  	  s0->total_pkts++;
  	  s0->total_bytes += vlib_buffer_length_in_chain (vm, b0);
  	  /* Per-B4 LRU list maintenance */
  	  clib_dlist_remove (dm->per_thread_data[thread_index].list_pool,
  			     s0->per_b4_index);
  	  clib_dlist_addtail (dm->per_thread_data[thread_index].list_pool,
  			      s0->per_b4_list_head_index, s0->per_b4_index);
  
  	  ip40->tos =
  	    (clib_net_to_host_u32
  	     (ip60->ip_version_traffic_class_and_flow_label) & 0x0ff00000) >>
  	    20;
  	  vlib_buffer_advance (b0, sizeof (ip6_header_t));
  
  	trace0:
  	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
  			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
  	    {
  	      dslite_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
  	      t->next_index = next0;
  	      t->session_index = ~0;
  	      if (s0)
  		t->session_index =
  		  s0 - dm->per_thread_data[thread_index].sessions;
  	    }
  
  	  b0->error = error_node->errors[error0];
  
  	  /* 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;
  }
  
  VLIB_NODE_FN (dslite_in2out_node) (vlib_main_t * vm,
  				   vlib_node_runtime_t * node,
  				   vlib_frame_t * frame)
  {
    return dslite_in2out_node_fn_inline (vm, node, frame, 0);
  }
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (dslite_in2out_node) = {
    .name = "dslite-in2out",
    .vector_size = sizeof (u32),
    .format_trace = format_dslite_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
    .n_errors = ARRAY_LEN (dslite_in2out_error_strings),
    .error_strings = dslite_in2out_error_strings,
    .n_next_nodes = DSLITE_IN2OUT_N_NEXT,
    /* edit / add dispositions here */
    .next_nodes = {
      [DSLITE_IN2OUT_NEXT_DROP] = "error-drop",
      [DSLITE_IN2OUT_NEXT_IP4_LOOKUP] = "ip4-lookup",
      [DSLITE_IN2OUT_NEXT_IP6_ICMP] = "ip6-icmp-input",
      [DSLITE_IN2OUT_NEXT_SLOWPATH] = "dslite-in2out-slowpath",
    },
  };
  /* *INDENT-ON* */
  
  VLIB_NODE_FN (dslite_in2out_slowpath_node) (vlib_main_t * vm,
  					    vlib_node_runtime_t * node,
  					    vlib_frame_t * frame)
  {
    return dslite_in2out_node_fn_inline (vm, node, frame, 1);
  }
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (dslite_in2out_slowpath_node) = {
    .name = "dslite-in2out-slowpath",
    .vector_size = sizeof (u32),
    .format_trace = format_dslite_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
    .n_errors = ARRAY_LEN (dslite_in2out_error_strings),
    .error_strings = dslite_in2out_error_strings,
    .n_next_nodes = DSLITE_IN2OUT_N_NEXT,
    /* edit / add dispositions here */
    .next_nodes = {
      [DSLITE_IN2OUT_NEXT_DROP] = "error-drop",
      [DSLITE_IN2OUT_NEXT_IP4_LOOKUP] = "ip4-lookup",
      [DSLITE_IN2OUT_NEXT_IP6_ICMP] = "ip6-lookup",
      [DSLITE_IN2OUT_NEXT_SLOWPATH] = "dslite-in2out-slowpath",
    },
  };
  /* *INDENT-ON* */
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  