src/plugins/nat/nat64_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 /**
  16  * @file
  17  * @brief NAT64 IPv4 to IPv6 translation (otside to inside network)
  18  */
  19
  20 #include <nat/nat64.h>
  21 #include <vnet/ip/ip4_to_ip6.h>
  22 #include <vnet/fib/ip4_fib.h>
  23
  24 typedef struct
  25 {
  26   u32 sw_if_index;
  27   u32 next_index;
  28 } nat64_out2in_trace_t;
  29
  30 static u8 *
  31 format_nat64_out2in_trace (u8 * s, va_list * args)
  32 {
  33   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  34   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  35   nat64_out2in_trace_t *t = va_arg (*args, nat64_out2in_trace_t *);
  36
  37   s =
  38     format (s, "NAT64-out2in: sw_if_index %d, next index %d", t->sw_if_index,
  39             t->next_index);
  40
  41   return s;
  42 }
  43
  44 vlib_node_registration_t nat64_out2in_node;
  45
  46 #define foreach_nat64_out2in_error                 \
  47 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")    \
  48 _(OUT2IN_PACKETS, "Good out2in packets processed") \
  49 _(NO_TRANSLATION, "No translation")                \
  50 _(UNKNOWN, "unknown")
  51
  52 typedef enum
  53 {
  54 #define _(sym,str) NAT64_OUT2IN_ERROR_##sym,
  55   foreach_nat64_out2in_error
  56 #undef _
  57     NAT64_OUT2IN_N_ERROR,
  58 } nat64_out2in_error_t;
  59
  60 static char *nat64_out2in_error_strings[] = {
  61 #define _(sym,string) string,
  62   foreach_nat64_out2in_error
  63 #undef _
  64 };
  65
  66 typedef enum
  67 {
  68   NAT64_OUT2IN_NEXT_LOOKUP,
  69   NAT64_OUT2IN_NEXT_DROP,
  70   NAT64_OUT2IN_N_NEXT,
  71 } nat64_out2in_next_t;
  72
  73 typedef struct nat64_out2in_set_ctx_t_
  74 {
  75   vlib_buffer_t *b;
  76   vlib_main_t *vm;
  77 } nat64_out2in_set_ctx_t;
  78
  79 static int
  80 nat64_out2in_tcp_udp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
  81                              void *arg)
  82 {
  83   nat64_main_t *nm = &nat64_main;
  84   nat64_out2in_set_ctx_t *ctx = arg;
  85   nat64_db_bib_entry_t *bibe;
  86   nat64_db_st_entry_t *ste;
  87   ip46_address_t saddr, daddr;
  88   ip6_address_t ip6_saddr;
  89   udp_header_t *udp = ip4_next_header (ip4);
  90   tcp_header_t *tcp = ip4_next_header (ip4);
  91   u8 proto = ip4->protocol;
  92   u16 dport = udp->dst_port;
  93   u16 sport = udp->src_port;
  94   u32 sw_if_index, fib_index;
  95   u16 *checksum;
  96   ip_csum_t csum;
  97
  98   sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
  99   fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
 100
 101   memset (&saddr, 0, sizeof (saddr));
 102   saddr.ip4.as_u32 = ip4->src_address.as_u32;
 103   memset (&daddr, 0, sizeof (daddr));
 104   daddr.ip4.as_u32 = ip4->dst_address.as_u32;
 105
 106   ste =
 107     nat64_db_st_entry_find (&nm->db, &daddr, &saddr, dport, sport, proto,
 108                             fib_index, 0);
 109   if (ste)
 110     {
 111       bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
 112       if (!bibe)
 113         return -1;
 114     }
 115   else
 116     {
 117       bibe =
 118         nat64_db_bib_entry_find (&nm->db, &daddr, dport, proto, fib_index, 0);
 119
 120       if (!bibe)
 121         return -1;
 122
 123       nat64_compose_ip6 (&ip6_saddr, &ip4->src_address, bibe->fib_index);
 124       ste =
 125         nat64_db_st_entry_create (&nm->db, bibe, &ip6_saddr, &saddr.ip4,
 126                                   sport);
 127     }
 128
 129   nat64_session_reset_timeout (ste, ctx->vm);
 130
 131   ip6->src_address.as_u64[0] = ste->in_r_addr.as_u64[0];
 132   ip6->src_address.as_u64[1] = ste->in_r_addr.as_u64[1];
 133
 134   ip6->dst_address.as_u64[0] = bibe->in_addr.as_u64[0];
 135   ip6->dst_address.as_u64[1] = bibe->in_addr.as_u64[1];
 136   udp->dst_port = bibe->in_port;
 137
 138   if (proto == IP_PROTOCOL_UDP)
 139     checksum = &udp->checksum;
 140   else
 141     checksum = &tcp->checksum;
 142   csum = ip_csum_sub_even (*checksum, dport);
 143   csum = ip_csum_add_even (csum, udp->dst_port);
 144   *checksum = ip_csum_fold (csum);
 145
 146   vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
 147
 148   return 0;
 149 }
 150
 151 static int
 152 nat64_out2in_icmp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6, void *arg)
 153 {
 154   nat64_main_t *nm = &nat64_main;
 155   nat64_out2in_set_ctx_t *ctx = arg;
 156   nat64_db_bib_entry_t *bibe;
 157   nat64_db_st_entry_t *ste;
 158   ip46_address_t saddr, daddr;
 159   ip6_address_t ip6_saddr;
 160   u32 sw_if_index, fib_index;
 161   icmp46_header_t *icmp = ip4_next_header (ip4);
 162
 163   sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
 164   fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
 165
 166   memset (&saddr, 0, sizeof (saddr));
 167   saddr.ip4.as_u32 = ip4->src_address.as_u32;
 168   memset (&daddr, 0, sizeof (daddr));
 169   daddr.ip4.as_u32 = ip4->dst_address.as_u32;
 170
 171   if (icmp->type == ICMP6_echo_request || icmp->type == ICMP6_echo_reply)
 172     {
 173       u16 out_id = ((u16 *) (icmp))[2];
 174       ste =
 175         nat64_db_st_entry_find (&nm->db, &daddr, &saddr, out_id, 0,
 176                                 IP_PROTOCOL_ICMP, fib_index, 0);
 177
 178       if (ste)
 179         {
 180           bibe =
 181             nat64_db_bib_entry_by_index (&nm->db, IP_PROTOCOL_ICMP,
 182                                          ste->bibe_index);
 183           if (!bibe)
 184             return -1;
 185         }
 186       else
 187         {
 188           bibe =
 189             nat64_db_bib_entry_find (&nm->db, &daddr, out_id,
 190                                      IP_PROTOCOL_ICMP, fib_index, 0);
 191           if (!bibe)
 192             return -1;
 193
 194           nat64_compose_ip6 (&ip6_saddr, &ip4->src_address, bibe->fib_index);
 195           ste =
 196             nat64_db_st_entry_create (&nm->db, bibe, &ip6_saddr, &saddr.ip4,
 197                                       0);
 198         }
 199
 200       nat64_session_reset_timeout (ste, ctx->vm);
 201
 202       ip6->src_address.as_u64[0] = ste->in_r_addr.as_u64[0];
 203       ip6->src_address.as_u64[1] = ste->in_r_addr.as_u64[1];
 204
 205       ip6->dst_address.as_u64[0] = bibe->in_addr.as_u64[0];
 206       ip6->dst_address.as_u64[1] = bibe->in_addr.as_u64[1];
 207       ((u16 *) (icmp))[2] = bibe->in_port;
 208
 209       vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
 210     }
 211   else
 212     {
 213       ip6_header_t *inner_ip6 = (ip6_header_t *) u8_ptr_add (icmp, 8);
 214
 215       nat64_compose_ip6 (&ip6->src_address, &ip4->src_address,
 216                          vnet_buffer (ctx->b)->sw_if_index[VLIB_TX]);
 217       ip6->dst_address.as_u64[0] = inner_ip6->src_address.as_u64[0];
 218       ip6->dst_address.as_u64[1] = inner_ip6->src_address.as_u64[1];
 219     }
 220
 221   return 0;
 222 }
 223
 224 static int
 225 nat64_out2in_inner_icmp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
 226                                 void *arg)
 227 {
 228   nat64_main_t *nm = &nat64_main;
 229   nat64_out2in_set_ctx_t *ctx = arg;
 230   nat64_db_bib_entry_t *bibe;
 231   nat64_db_st_entry_t *ste;
 232   ip46_address_t saddr, daddr;
 233   u32 sw_if_index, fib_index;
 234   u8 proto = ip4->protocol;
 235
 236   sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
 237   fib_index =
 238     fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6, sw_if_index);
 239
 240   memset (&saddr, 0, sizeof (saddr));
 241   saddr.ip4.as_u32 = ip4->src_address.as_u32;
 242   memset (&daddr, 0, sizeof (daddr));
 243   daddr.ip4.as_u32 = ip4->dst_address.as_u32;
 244
 245   if (proto == IP_PROTOCOL_ICMP6)
 246     {
 247       icmp46_header_t *icmp = ip4_next_header (ip4);
 248       u16 out_id = ((u16 *) (icmp))[2];
 249       proto = IP_PROTOCOL_ICMP;
 250
 251       if (!
 252           (icmp->type == ICMP6_echo_request
 253            || icmp->type == ICMP6_echo_reply))
 254         return -1;
 255
 256       ste =
 257         nat64_db_st_entry_find (&nm->db, &saddr, &daddr, out_id, 0, proto,
 258                                 fib_index, 0);
 259       if (!ste)
 260         return -1;
 261
 262       bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
 263       if (!bibe)
 264         return -1;
 265
 266       ip6->dst_address.as_u64[0] = ste->in_r_addr.as_u64[0];
 267       ip6->dst_address.as_u64[1] = ste->in_r_addr.as_u64[1];
 268       ip6->src_address.as_u64[0] = bibe->in_addr.as_u64[0];
 269       ip6->src_address.as_u64[1] = bibe->in_addr.as_u64[1];
 270       ((u16 *) (icmp))[2] = bibe->in_port;
 271
 272       vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
 273     }
 274   else
 275     {
 276       udp_header_t *udp = ip4_next_header (ip4);
 277       tcp_header_t *tcp = ip4_next_header (ip4);
 278       u16 dport = udp->dst_port;
 279       u16 sport = udp->src_port;
 280       u16 *checksum;
 281       ip_csum_t csum;
 282
 283       ste =
 284         nat64_db_st_entry_find (&nm->db, &saddr, &daddr, sport, dport, proto,
 285                                 fib_index, 0);
 286       if (!ste)
 287         return -1;
 288
 289       bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
 290       if (!bibe)
 291         return -1;
 292
 293       nat64_compose_ip6 (&ip6->dst_address, &daddr.ip4, bibe->fib_index);
 294       ip6->src_address.as_u64[0] = bibe->in_addr.as_u64[0];
 295       ip6->src_address.as_u64[1] = bibe->in_addr.as_u64[1];
 296       udp->src_port = bibe->in_port;
 297
 298       if (proto == IP_PROTOCOL_UDP)
 299         checksum = &udp->checksum;
 300       else
 301         checksum = &tcp->checksum;
 302       if (*checksum)
 303         {
 304           csum = ip_csum_sub_even (*checksum, sport);
 305           csum = ip_csum_add_even (csum, udp->src_port);
 306           *checksum = ip_csum_fold (csum);
 307         }
 308
 309       vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
 310     }
 311
 312   return 0;
 313 }
 314
 315 static int
 316 nat64_out2in_unk_proto_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
 317                                void *arg)
 318 {
 319   nat64_main_t *nm = &nat64_main;
 320   nat64_out2in_set_ctx_t *ctx = arg;
 321   nat64_db_bib_entry_t *bibe;
 322   nat64_db_st_entry_t *ste;
 323   ip46_address_t saddr, daddr;
 324   ip6_address_t ip6_saddr;
 325   u32 sw_if_index, fib_index;
 326   u8 proto = ip4->protocol;
 327
 328   sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
 329   fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
 330
 331   memset (&saddr, 0, sizeof (saddr));
 332   saddr.ip4.as_u32 = ip4->src_address.as_u32;
 333   memset (&daddr, 0, sizeof (daddr));
 334   daddr.ip4.as_u32 = ip4->dst_address.as_u32;
 335
 336   ste =
 337     nat64_db_st_entry_find (&nm->db, &daddr, &saddr, 0, 0, proto, fib_index,
 338                             0);
 339   if (ste)
 340     {
 341       bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
 342       if (!bibe)
 343         return -1;
 344     }
 345   else
 346     {
 347       bibe =
 348         nat64_db_bib_entry_find (&nm->db, &daddr, 0, proto, fib_index, 0);
 349
 350       if (!bibe)
 351         return -1;
 352
 353       nat64_compose_ip6 (&ip6_saddr, &ip4->src_address, bibe->fib_index);
 354       ste =
 355         nat64_db_st_entry_create (&nm->db, bibe, &ip6_saddr, &saddr.ip4, 0);
 356     }
 357
 358   nat64_session_reset_timeout (ste, ctx->vm);
 359
 360   ip6->src_address.as_u64[0] = ste->in_r_addr.as_u64[0];
 361   ip6->src_address.as_u64[1] = ste->in_r_addr.as_u64[1];
 362
 363   ip6->dst_address.as_u64[0] = bibe->in_addr.as_u64[0];
 364   ip6->dst_address.as_u64[1] = bibe->in_addr.as_u64[1];
 365
 366   vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
 367
 368   return 0;
 369 }
 370
 371 static uword
 372 nat64_out2in_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 373                       vlib_frame_t * frame)
 374 {
 375   u32 n_left_from, *from, *to_next;
 376   nat64_out2in_next_t next_index;
 377   u32 pkts_processed = 0;
 378
 379   from = vlib_frame_vector_args (frame);
 380   n_left_from = frame->n_vectors;
 381   next_index = node->cached_next_index;
 382   while (n_left_from > 0)
 383     {
 384       u32 n_left_to_next;
 385
 386       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 387
 388       while (n_left_from > 0 && n_left_to_next > 0)
 389         {
 390           u32 bi0;
 391           vlib_buffer_t *b0;
 392           u32 next0;
 393           ip4_header_t *ip40;
 394           u32 proto0;
 395           nat64_out2in_set_ctx_t ctx0;
 396
 397           /* speculatively enqueue b0 to the current next frame */
 398           bi0 = from[0];
 399           to_next[0] = bi0;
 400           from += 1;
 401           to_next += 1;
 402           n_left_from -= 1;
 403           n_left_to_next -= 1;
 404
 405           b0 = vlib_get_buffer (vm, bi0);
 406           ip40 = vlib_buffer_get_current (b0);
 407
 408           ctx0.b = b0;
 409           ctx0.vm = vm;
 410
 411           next0 = NAT64_OUT2IN_NEXT_LOOKUP;
 412
 413           proto0 = ip_proto_to_snat_proto (ip40->protocol);
 414
 415           if (proto0 == SNAT_PROTOCOL_ICMP)
 416             {
 417               if (icmp_to_icmp6
 418                   (b0, nat64_out2in_icmp_set_cb, &ctx0,
 419                    nat64_out2in_inner_icmp_set_cb, &ctx0))
 420                 {
 421                   next0 = NAT64_OUT2IN_NEXT_DROP;
 422                   b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
 423                   goto trace0;
 424                 }
 425             }
 426           else if (proto0 == SNAT_PROTOCOL_TCP || proto0 == SNAT_PROTOCOL_UDP)
 427             {
 428               if (ip4_to_ip6_tcp_udp (b0, nat64_out2in_tcp_udp_set_cb, &ctx0))
 429                 {
 430                   next0 = NAT64_OUT2IN_NEXT_DROP;
 431                   b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
 432                   goto trace0;
 433                 }
 434             }
 435           else
 436             {
 437               if (ip4_to_ip6 (b0, nat64_out2in_unk_proto_set_cb, &ctx0))
 438                 {
 439                   next0 = NAT64_OUT2IN_NEXT_DROP;
 440                   b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
 441                   goto trace0;
 442                 }
 443             }
 444
 445         trace0:
 446           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 447                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 448             {
 449               nat64_out2in_trace_t *t =
 450                 vlib_add_trace (vm, node, b0, sizeof (*t));
 451               t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 452               t->next_index = next0;
 453             }
 454
 455           pkts_processed += next0 != NAT64_OUT2IN_NEXT_DROP;
 456
 457           /* verify speculative enqueue, maybe switch current next frame */
 458           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 459                                            n_left_to_next, bi0, next0);
 460         }
 461       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 462     }
 463   vlib_node_increment_counter (vm, nat64_out2in_node.index,
 464                                NAT64_OUT2IN_ERROR_OUT2IN_PACKETS,
 465                                pkts_processed);
 466   return frame->n_vectors;
 467 }
 468
 469 /* *INDENT-OFF* */
 470 VLIB_REGISTER_NODE (nat64_out2in_node) = {
 471   .function = nat64_out2in_node_fn,
 472   .name = "nat64-out2in",
 473   .vector_size = sizeof (u32),
 474   .format_trace = format_nat64_out2in_trace,
 475   .type = VLIB_NODE_TYPE_INTERNAL,
 476   .n_errors = ARRAY_LEN (nat64_out2in_error_strings),
 477   .error_strings = nat64_out2in_error_strings,.n_next_nodes = 2,
 478   /* edit / add dispositions here */
 479   .next_nodes = {
 480     [NAT64_OUT2IN_NEXT_DROP] = "error-drop",
 481     [NAT64_OUT2IN_NEXT_LOOKUP] = "ip6-lookup",
 482   },
 483 };
 484 /* *INDENT-ON* */
 485
 486 VLIB_NODE_FUNCTION_MULTIARCH (nat64_out2in_node, nat64_out2in_node_fn);
 487
 488 /*
 489  * fd.io coding-style-patch-verification: ON
 490  *
 491  * Local Variables:
 492  * eval: (c-set-style "gnu")
 493  * End:
 494  */