src/plugins/snat/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 <snat/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   snat_protocol_t proto = ip_proto_to_snat_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 == SNAT_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                                 SNAT_PROTOCOL_ICMP, fib_index, 0);
 177
 178       if (ste)
 179         {
 180           bibe =
 181             nat64_db_bib_entry_by_index (&nm->db, SNAT_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                                      SNAT_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   snat_protocol_t proto = ip_proto_to_snat_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 == SNAT_PROTOCOL_ICMP)
 246     {
 247       icmp46_header_t *icmp = ip4_next_header (ip4);
 248       u16 out_id = ((u16 *) (icmp))[2];
 249
 250       if (!
 251           (icmp->type == ICMP6_echo_request
 252            || icmp->type == ICMP6_echo_reply))
 253         return -1;
 254
 255       ste =
 256         nat64_db_st_entry_find (&nm->db, &saddr, &daddr, out_id, 0, proto,
 257                                 fib_index, 0);
 258       if (!ste)
 259         return -1;
 260
 261       bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
 262       if (!bibe)
 263         return -1;
 264
 265       ip6->dst_address.as_u64[0] = ste->in_r_addr.as_u64[0];
 266       ip6->dst_address.as_u64[1] = ste->in_r_addr.as_u64[1];
 267       ip6->src_address.as_u64[0] = bibe->in_addr.as_u64[0];
 268       ip6->src_address.as_u64[1] = bibe->in_addr.as_u64[1];
 269       ((u16 *) (icmp))[2] = bibe->in_port;
 270
 271       vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
 272     }
 273   else
 274     {
 275       udp_header_t *udp = ip4_next_header (ip4);
 276       tcp_header_t *tcp = ip4_next_header (ip4);
 277       u16 dport = udp->dst_port;
 278       u16 sport = udp->src_port;
 279       u16 *checksum;
 280       ip_csum_t csum;
 281
 282       ste =
 283         nat64_db_st_entry_find (&nm->db, &saddr, &daddr, sport, dport, proto,
 284                                 fib_index, 0);
 285       if (!ste)
 286         return -1;
 287
 288       bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
 289       if (!bibe)
 290         return -1;
 291
 292       nat64_compose_ip6 (&ip6->dst_address, &daddr.ip4, bibe->fib_index);
 293       ip6->src_address.as_u64[0] = bibe->in_addr.as_u64[0];
 294       ip6->src_address.as_u64[1] = bibe->in_addr.as_u64[1];
 295       udp->src_port = bibe->in_port;
 296
 297       if (proto == SNAT_PROTOCOL_UDP)
 298         checksum = &udp->checksum;
 299       else
 300         checksum = &tcp->checksum;
 301       if (*checksum)
 302         {
 303           csum = ip_csum_sub_even (*checksum, sport);
 304           csum = ip_csum_add_even (csum, udp->src_port);
 305           *checksum = ip_csum_fold (csum);
 306         }
 307
 308       vnet_buffer (ctx->b)->sw_if_index[VLIB_TX] = bibe->fib_index;
 309     }
 310
 311   return 0;
 312 }
 313
 314 static uword
 315 nat64_out2in_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 316                       vlib_frame_t * frame)
 317 {
 318   u32 n_left_from, *from, *to_next;
 319   nat64_out2in_next_t next_index;
 320   u32 pkts_processed = 0;
 321
 322   from = vlib_frame_vector_args (frame);
 323   n_left_from = frame->n_vectors;
 324   next_index = node->cached_next_index;
 325   while (n_left_from > 0)
 326     {
 327       u32 n_left_to_next;
 328
 329       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 330
 331       while (n_left_from > 0 && n_left_to_next > 0)
 332         {
 333           u32 bi0;
 334           vlib_buffer_t *b0;
 335           u32 next0;
 336           ip4_header_t *ip40;
 337           u32 proto0;
 338           nat64_out2in_set_ctx_t ctx0;
 339
 340           /* speculatively enqueue b0 to the current next frame */
 341           bi0 = from[0];
 342           to_next[0] = bi0;
 343           from += 1;
 344           to_next += 1;
 345           n_left_from -= 1;
 346           n_left_to_next -= 1;
 347
 348           b0 = vlib_get_buffer (vm, bi0);
 349           ip40 = vlib_buffer_get_current (b0);
 350
 351           ctx0.b = b0;
 352           ctx0.vm = vm;
 353
 354           next0 = NAT64_OUT2IN_NEXT_LOOKUP;
 355
 356           proto0 = ip_proto_to_snat_proto (ip40->protocol);
 357           if (PREDICT_FALSE (proto0 == ~0))
 358             {
 359               next0 = NAT64_OUT2IN_NEXT_DROP;
 360               b0->error =
 361                 node->errors[NAT64_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 362               goto trace0;
 363             }
 364
 365           if (proto0 == SNAT_PROTOCOL_ICMP)
 366             {
 367               if (icmp_to_icmp6
 368                   (b0, nat64_out2in_icmp_set_cb, &ctx0,
 369                    nat64_out2in_inner_icmp_set_cb, &ctx0))
 370                 {
 371                   next0 = NAT64_OUT2IN_NEXT_DROP;
 372                   b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
 373                   goto trace0;
 374                 }
 375             }
 376           else
 377             {
 378               if (ip4_to_ip6_tcp_udp (b0, nat64_out2in_tcp_udp_set_cb, &ctx0))
 379                 {
 380                   next0 = NAT64_OUT2IN_NEXT_DROP;
 381                   b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
 382                   goto trace0;
 383                 }
 384             }
 385
 386         trace0:
 387           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 388                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 389             {
 390               nat64_out2in_trace_t *t =
 391                 vlib_add_trace (vm, node, b0, sizeof (*t));
 392               t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 393               t->next_index = next0;
 394             }
 395
 396           pkts_processed += next0 != NAT64_OUT2IN_NEXT_DROP;
 397
 398           /* verify speculative enqueue, maybe switch current next frame */
 399           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 400                                            n_left_to_next, bi0, next0);
 401         }
 402       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 403     }
 404   vlib_node_increment_counter (vm, nat64_out2in_node.index,
 405                                NAT64_OUT2IN_ERROR_OUT2IN_PACKETS,
 406                                pkts_processed);
 407   return frame->n_vectors;
 408 }
 409
 410 /* *INDENT-OFF* */
 411 VLIB_REGISTER_NODE (nat64_out2in_node) = {
 412   .function = nat64_out2in_node_fn,
 413   .name = "nat64-out2in",
 414   .vector_size = sizeof (u32),
 415   .format_trace = format_nat64_out2in_trace,
 416   .type = VLIB_NODE_TYPE_INTERNAL,
 417   .n_errors = ARRAY_LEN (nat64_out2in_error_strings),
 418   .error_strings = nat64_out2in_error_strings,.n_next_nodes = 2,
 419   /* edit / add dispositions here */
 420   .next_nodes = {
 421     [NAT64_OUT2IN_NEXT_DROP] = "error-drop",
 422     [NAT64_OUT2IN_NEXT_LOOKUP] = "ip6-lookup",
 423   },
 424 };
 425 /* *INDENT-ON* */
 426
 427 VLIB_NODE_FUNCTION_MULTIARCH (nat64_out2in_node, nat64_out2in_node_fn);
 428
 429 /*
 430  * fd.io coding-style-patch-verification: ON
 431  *
 432  * Local Variables:
 433  * eval: (c-set-style "gnu")
 434  * End:
 435  */