src/plugins/nat/dslite/dslite_out2in.c

   1 /*
   2  * Copyright (c) 2017 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 #include <nat/dslite/dslite.h>
  16
  17 typedef enum
  18 {
  19   DSLITE_OUT2IN_NEXT_IP4_LOOKUP,
  20   DSLITE_OUT2IN_NEXT_IP6_LOOKUP,
  21   DSLITE_OUT2IN_NEXT_DROP,
  22   DSLITE_OUT2IN_N_NEXT,
  23 } dslite_out2in_next_t;
  24
  25 static char *dslite_out2in_error_strings[] = {
  26 #define _(sym,string) string,
  27   foreach_dslite_error
  28 #undef _
  29 };
  30
  31 static inline u32
  32 dslite_icmp_out2in (dslite_main_t * dm, ip4_header_t * ip4,
  33                     dslite_session_t ** sp, u32 next, u8 * error,
  34                     u32 thread_index)
  35 {
  36   dslite_session_t *s = 0;
  37   icmp46_header_t *icmp = ip4_next_header (ip4);
  38   clib_bihash_kv_8_8_t kv, value;
  39   nat_session_key_t key;
  40   u32 n = next;
  41   echo_header_t *echo;
  42   u32 new_addr, old_addr;
  43   u16 old_id, new_id;
  44   ip_csum_t sum;
  45
  46   echo = (echo_header_t *) (icmp + 1);
  47
  48   if (icmp_type_is_error_message (icmp->type)
  49       || (icmp->type != ICMP4_echo_reply))
  50     {
  51       n = DSLITE_OUT2IN_NEXT_DROP;
  52       *error = DSLITE_ERROR_BAD_ICMP_TYPE;
  53       goto done;
  54     }
  55
  56   key.addr = ip4->dst_address;
  57   key.port = echo->identifier;
  58   key.protocol = NAT_PROTOCOL_ICMP;
  59   key.fib_index = 0;
  60   kv.key = key.as_u64;
  61
  62   if (clib_bihash_search_8_8
  63       (&dm->per_thread_data[thread_index].out2in, &kv, &value))
  64     {
  65       next = DSLITE_OUT2IN_NEXT_DROP;
  66       *error = DSLITE_ERROR_NO_TRANSLATION;
  67       goto done;
  68     }
  69   else
  70     {
  71       s =
  72         pool_elt_at_index (dm->per_thread_data[thread_index].sessions,
  73                            value.value);
  74     }
  75
  76   old_id = echo->identifier;
  77   echo->identifier = new_id = s->in2out.port;
  78   sum = icmp->checksum;
  79   sum = ip_csum_update (sum, old_id, new_id, echo_header_t, identifier);
  80   icmp->checksum = ip_csum_fold (sum);
  81
  82   old_addr = ip4->dst_address.as_u32;
  83   ip4->dst_address = s->in2out.addr;
  84   new_addr = ip4->dst_address.as_u32;
  85
  86   sum = ip4->checksum;
  87   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
  88   ip4->checksum = ip_csum_fold (sum);
  89
  90 done:
  91   *sp = s;
  92   return n;
  93 }
  94
  95 VLIB_NODE_FN (dslite_out2in_node) (vlib_main_t * vm,
  96                                    vlib_node_runtime_t * node,
  97                                    vlib_frame_t * frame)
  98 {
  99   u32 n_left_from, *from, *to_next;
 100   dslite_out2in_next_t next_index;
 101   vlib_node_runtime_t *error_node;
 102   u32 thread_index = vm->thread_index;
 103   f64 now = vlib_time_now (vm);
 104   dslite_main_t *dm = &dslite_main;
 105
 106   error_node = vlib_node_get_runtime (vm, dm->dslite_out2in_node_index);
 107
 108   from = vlib_frame_vector_args (frame);
 109   n_left_from = frame->n_vectors;
 110   next_index = node->cached_next_index;
 111
 112
 113   while (n_left_from > 0)
 114     {
 115       u32 n_left_to_next;
 116
 117       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 118
 119       while (n_left_from > 0 && n_left_to_next > 0)
 120         {
 121           u32 bi0;
 122           vlib_buffer_t *b0;
 123           u32 next0 = DSLITE_OUT2IN_NEXT_IP6_LOOKUP;
 124           u8 error0 = DSLITE_ERROR_OUT2IN;
 125           ip4_header_t *ip40;
 126           ip6_header_t *ip60;
 127           u32 proto0;
 128           udp_header_t *udp0;
 129           tcp_header_t *tcp0;
 130           clib_bihash_kv_8_8_t kv0, value0;
 131           nat_session_key_t key0;
 132           dslite_session_t *s0 = 0;
 133           ip_csum_t sum0;
 134           u32 new_addr0, old_addr0;
 135           u16 new_port0, old_port0;
 136
 137           /* speculatively enqueue b0 to the current next frame */
 138           bi0 = from[0];
 139           to_next[0] = bi0;
 140           from += 1;
 141           to_next += 1;
 142           n_left_from -= 1;
 143           n_left_to_next -= 1;
 144
 145           b0 = vlib_get_buffer (vm, bi0);
 146           ip40 = vlib_buffer_get_current (b0);
 147           proto0 = ip_proto_to_nat_proto (ip40->protocol);
 148
 149           if (PREDICT_FALSE (proto0 == ~0))
 150             {
 151               error0 = DSLITE_ERROR_UNSUPPORTED_PROTOCOL;
 152               next0 = DSLITE_OUT2IN_NEXT_DROP;
 153               goto trace0;
 154             }
 155
 156           if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 157             {
 158               next0 =
 159                 dslite_icmp_out2in (dm, ip40, &s0, next0, &error0,
 160                                     thread_index);
 161               if (PREDICT_FALSE (next0 == DSLITE_OUT2IN_NEXT_DROP))
 162                 goto trace0;
 163
 164               goto encap0;
 165             }
 166
 167           udp0 = ip4_next_header (ip40);
 168           tcp0 = (tcp_header_t *) udp0;
 169
 170           key0.addr = ip40->dst_address;
 171           key0.port = udp0->dst_port;
 172           key0.protocol = proto0;
 173           key0.fib_index = 0;
 174           kv0.key = key0.as_u64;
 175
 176           if (clib_bihash_search_8_8
 177               (&dm->per_thread_data[thread_index].out2in, &kv0, &value0))
 178             {
 179               next0 = DSLITE_OUT2IN_NEXT_DROP;
 180               error0 = DSLITE_ERROR_NO_TRANSLATION;
 181               goto trace0;
 182             }
 183           else
 184             {
 185               s0 =
 186                 pool_elt_at_index (dm->per_thread_data[thread_index].sessions,
 187                                    value0.value);
 188             }
 189
 190           old_addr0 = ip40->dst_address.as_u32;
 191           ip40->dst_address = s0->in2out.addr;
 192           new_addr0 = ip40->dst_address.as_u32;
 193
 194           sum0 = ip40->checksum;
 195           sum0 =
 196             ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 197                             dst_address);
 198           ip40->checksum = ip_csum_fold (sum0);
 199
 200           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 201             {
 202               old_port0 = tcp0->dst_port;
 203               tcp0->dst_port = s0->in2out.port;
 204               new_port0 = tcp0->dst_port;
 205
 206               sum0 = tcp0->checksum;
 207               sum0 =
 208                 ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 209                                 dst_address);
 210               sum0 =
 211                 ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
 212                                 length);
 213               tcp0->checksum = ip_csum_fold (sum0);
 214             }
 215           else
 216             {
 217               old_port0 = udp0->dst_port;
 218               udp0->dst_port = s0->in2out.port;
 219               udp0->checksum = 0;
 220             }
 221
 222         encap0:
 223           /* Construct IPv6 header */
 224           vlib_buffer_advance (b0, -(sizeof (ip6_header_t)));
 225           ip60 = vlib_buffer_get_current (b0);
 226           ip60->ip_version_traffic_class_and_flow_label =
 227             clib_host_to_net_u32 ((6 << 28) + (ip40->tos << 20));
 228           ip60->payload_length = ip40->length;
 229           ip60->protocol = IP_PROTOCOL_IP_IN_IP;
 230           ip60->hop_limit = ip40->ttl;
 231           ip60->src_address.as_u64[0] = dm->aftr_ip6_addr.as_u64[0];
 232           ip60->src_address.as_u64[1] = dm->aftr_ip6_addr.as_u64[1];
 233           ip60->dst_address.as_u64[0] = s0->in2out.softwire_id.as_u64[0];
 234           ip60->dst_address.as_u64[1] = s0->in2out.softwire_id.as_u64[1];
 235
 236           /* Accounting */
 237           s0->last_heard = now;
 238           s0->total_pkts++;
 239           s0->total_bytes += vlib_buffer_length_in_chain (vm, b0);
 240           /* Per-B4 LRU list maintenance */
 241           clib_dlist_remove (dm->per_thread_data[thread_index].list_pool,
 242                              s0->per_b4_index);
 243           clib_dlist_addtail (dm->per_thread_data[thread_index].list_pool,
 244                               s0->per_b4_list_head_index, s0->per_b4_index);
 245         trace0:
 246           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 247                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 248             {
 249               dslite_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
 250               t->next_index = next0;
 251               t->session_index = ~0;
 252               if (s0)
 253                 t->session_index =
 254                   s0 - dm->per_thread_data[thread_index].sessions;
 255             }
 256
 257           b0->error = error_node->errors[error0];
 258
 259           /* verify speculative enqueue, maybe switch current next frame */
 260           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 261                                            n_left_to_next, bi0, next0);
 262         }
 263       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 264     }
 265
 266   return frame->n_vectors;
 267 }
 268
 269 /* *INDENT-OFF* */
 270 VLIB_REGISTER_NODE (dslite_out2in_node) = {
 271   .name = "dslite-out2in",
 272   .vector_size = sizeof (u32),
 273   .format_trace = format_dslite_trace,
 274   .type = VLIB_NODE_TYPE_INTERNAL,
 275   .n_errors = ARRAY_LEN (dslite_out2in_error_strings),
 276   .error_strings = dslite_out2in_error_strings,
 277   .n_next_nodes = DSLITE_OUT2IN_N_NEXT,
 278   /* edit / add dispositions here */
 279   .next_nodes = {
 280     [DSLITE_OUT2IN_NEXT_DROP] = "error-drop",
 281     [DSLITE_OUT2IN_NEXT_IP4_LOOKUP] = "ip4-lookup",
 282     [DSLITE_OUT2IN_NEXT_IP6_LOOKUP] = "ip6-lookup",
 283   },
 284 };
 285 /* *INDENT-ON* */
 286
 287 /*
 288  * fd.io coding-style-patch-verification: ON
 289  *
 290  * Local Variables:
 291  * eval: (c-set-style "gnu")
 292  * End:
 293  */