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 /* *INDENT-OFF* */
  25 static u8 well_known_prefix[] = {
  26   0x00, 0x64, 0xff, 0x9b,
  27   0x00, 0x00, 0x00, 0x00,
  28   0x00, 0x00, 0x00, 0x00,
  29   0x00, 0x00, 0x00, 0x00
  30  };
  31 /* *INDENT-ON* */
  32 typedef struct
  33 {
  34   u32 sw_if_index;
  35   u32 next_index;
  36 } nat64_out2in_trace_t;
  37
  38 static u8 *
  39 format_nat64_out2in_trace (u8 * s, va_list * args)
  40 {
  41   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  42   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  43   nat64_out2in_trace_t *t = va_arg (*args, nat64_out2in_trace_t *);
  44
  45   s =
  46     format (s, "NAT64-out2in: sw_if_index %d, next index %d", t->sw_if_index,
  47             t->next_index);
  48
  49   return s;
  50 }
  51
  52 vlib_node_registration_t nat64_out2in_node;
  53
  54 #define foreach_nat64_out2in_error                 \
  55 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")    \
  56 _(OUT2IN_PACKETS, "Good out2in packets processed") \
  57 _(NO_TRANSLATION, "No translation")                \
  58 _(UNKNOWN, "unknown")
  59
  60 typedef enum
  61 {
  62 #define _(sym,str) NAT64_OUT2IN_ERROR_##sym,
  63   foreach_nat64_out2in_error
  64 #undef _
  65     NAT64_OUT2IN_N_ERROR,
  66 } nat64_out2in_error_t;
  67
  68 static char *nat64_out2in_error_strings[] = {
  69 #define _(sym,string) string,
  70   foreach_nat64_out2in_error
  71 #undef _
  72 };
  73
  74 typedef enum
  75 {
  76   NAT64_OUT2IN_NEXT_LOOKUP,
  77   NAT64_OUT2IN_NEXT_DROP,
  78   NAT64_OUT2IN_N_NEXT,
  79 } nat64_out2in_next_t;
  80
  81 typedef struct nat64_out2in_set_ctx_t_
  82 {
  83   vlib_buffer_t *b;
  84   vlib_main_t *vm;
  85 } nat64_out2in_set_ctx_t;
  86
  87 static int
  88 nat64_out2in_tcp_udp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
  89                              void *arg)
  90 {
  91   nat64_main_t *nm = &nat64_main;
  92   nat64_out2in_set_ctx_t *ctx = arg;
  93   nat64_db_bib_entry_t *bibe;
  94   nat64_db_st_entry_t *ste;
  95   ip46_address_t saddr, daddr;
  96   ip6_address_t ip6_saddr;
  97   udp_header_t *udp = ip4_next_header (ip4);
  98   snat_protocol_t proto = ip_proto_to_snat_proto (ip4->protocol);
  99   u16 dport = udp->dst_port;
 100   u16 sport = udp->src_port;
 101   u32 sw_if_index, fib_index;
 102
 103   sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
 104   fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
 105
 106   memset (&saddr, 0, sizeof (saddr));
 107   saddr.ip4.as_u32 = ip4->src_address.as_u32;
 108   memset (&daddr, 0, sizeof (daddr));
 109   daddr.ip4.as_u32 = ip4->dst_address.as_u32;
 110
 111   memcpy (&ip6_saddr, well_known_prefix, sizeof (ip6_saddr));
 112   ip6_saddr.as_u32[3] = ip4->src_address.as_u32;
 113
 114   ste =
 115     nat64_db_st_entry_find (&nm->db, &daddr, &saddr, dport, sport, proto,
 116                             fib_index, 0);
 117   if (ste)
 118     {
 119       bibe = nat64_db_bib_entry_by_index (&nm->db, proto, ste->bibe_index);
 120       if (!bibe)
 121         return -1;
 122     }
 123   else
 124     {
 125       bibe =
 126         nat64_db_bib_entry_find (&nm->db, &daddr, dport, proto, fib_index, 0);
 127
 128       if (!bibe)
 129         return -1;
 130
 131       ste =
 132         nat64_db_st_entry_create (&nm->db, bibe, &ip6_saddr, &saddr.ip4,
 133                                   sport);
 134     }
 135
 136   nat64_session_reset_timeout (ste, ctx->vm);
 137
 138   ip6->src_address.as_u64[0] = ip6_saddr.as_u64[0];
 139   ip6->src_address.as_u64[1] = ip6_saddr.as_u64[1];
 140
 141   ip6->dst_address.as_u64[0] = bibe->in_addr.as_u64[0];
 142   ip6->dst_address.as_u64[1] = bibe->in_addr.as_u64[1];
 143   udp->dst_port = bibe->in_port;
 144
 145   return 0;
 146 }
 147
 148 static int
 149 nat64_out2in_icmp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6, void *arg)
 150 {
 151   nat64_main_t *nm = &nat64_main;
 152   nat64_out2in_set_ctx_t *ctx = arg;
 153   nat64_db_bib_entry_t *bibe;
 154   nat64_db_st_entry_t *ste;
 155   ip46_address_t saddr, daddr;
 156   ip6_address_t ip6_saddr;
 157   u32 sw_if_index, fib_index;
 158   icmp46_header_t *icmp = ip4_next_header (ip4);
 159
 160   sw_if_index = vnet_buffer (ctx->b)->sw_if_index[VLIB_RX];
 161   fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
 162
 163   memset (&saddr, 0, sizeof (saddr));
 164   saddr.ip4.as_u32 = ip4->src_address.as_u32;
 165   memset (&daddr, 0, sizeof (daddr));
 166   daddr.ip4.as_u32 = ip4->dst_address.as_u32;
 167
 168   memcpy (&ip6_saddr, well_known_prefix, sizeof (ip6_saddr));
 169   ip6_saddr.as_u32[3] = ip4->src_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           ste =
 195             nat64_db_st_entry_create (&nm->db, bibe, &ip6_saddr, &saddr.ip4,
 196                                       0);
 197         }
 198
 199       nat64_session_reset_timeout (ste, ctx->vm);
 200
 201       ip6->src_address.as_u64[0] = ip6_saddr.as_u64[0];
 202       ip6->src_address.as_u64[1] = ip6_saddr.as_u64[1];
 203
 204       ip6->dst_address.as_u64[0] = bibe->in_addr.as_u64[0];
 205       ip6->dst_address.as_u64[1] = bibe->in_addr.as_u64[1];
 206       ((u16 *) (icmp))[2] = bibe->in_port;
 207
 208     }
 209   else
 210     {
 211       //TODO: ICMP error
 212       clib_warning ("not ICMP echo request/reply, %u", icmp->type);
 213       return -1;
 214     }
 215
 216   return 0;
 217 }
 218
 219 static int
 220 nat64_out2in_inner_icmp_set_cb (ip4_header_t * ip4, ip6_header_t * ip6,
 221                                 void *ctx)
 222 {
 223   //TODO:
 224   return -1;
 225 }
 226
 227 static uword
 228 nat64_out2in_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 229                       vlib_frame_t * frame)
 230 {
 231   u32 n_left_from, *from, *to_next;
 232   nat64_out2in_next_t next_index;
 233   u32 pkts_processed = 0;
 234
 235   from = vlib_frame_vector_args (frame);
 236   n_left_from = frame->n_vectors;
 237   next_index = node->cached_next_index;
 238   while (n_left_from > 0)
 239     {
 240       u32 n_left_to_next;
 241
 242       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 243
 244       while (n_left_from > 0 && n_left_to_next > 0)
 245         {
 246           u32 bi0;
 247           vlib_buffer_t *b0;
 248           u32 next0;
 249           ip4_header_t *ip40;
 250           u32 proto0;
 251           nat64_out2in_set_ctx_t ctx0;
 252
 253           /* speculatively enqueue b0 to the current next frame */
 254           bi0 = from[0];
 255           to_next[0] = bi0;
 256           from += 1;
 257           to_next += 1;
 258           n_left_from -= 1;
 259           n_left_to_next -= 1;
 260
 261           b0 = vlib_get_buffer (vm, bi0);
 262           ip40 = vlib_buffer_get_current (b0);
 263
 264           ctx0.b = b0;
 265           ctx0.vm = vm;
 266
 267           next0 = NAT64_OUT2IN_NEXT_LOOKUP;
 268
 269           proto0 = ip_proto_to_snat_proto (ip40->protocol);
 270           if (PREDICT_FALSE (proto0 == ~0))
 271             {
 272               next0 = NAT64_OUT2IN_NEXT_DROP;
 273               b0->error =
 274                 node->errors[NAT64_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
 275               goto trace0;
 276             }
 277
 278           if (proto0 == SNAT_PROTOCOL_ICMP)
 279             {
 280               if (icmp_to_icmp6
 281                   (b0, nat64_out2in_icmp_set_cb, &ctx0,
 282                    nat64_out2in_inner_icmp_set_cb, &ctx0))
 283                 {
 284                   next0 = NAT64_OUT2IN_NEXT_DROP;
 285                   b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
 286                   goto trace0;
 287                 }
 288             }
 289           else
 290             {
 291               if (ip4_to_ip6_tcp_udp (b0, nat64_out2in_tcp_udp_set_cb, &ctx0))
 292                 {
 293                   next0 = NAT64_OUT2IN_NEXT_DROP;
 294                   b0->error = node->errors[NAT64_OUT2IN_ERROR_NO_TRANSLATION];
 295                   goto trace0;
 296                 }
 297             }
 298
 299         trace0:
 300           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 301                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 302             {
 303               nat64_out2in_trace_t *t =
 304                 vlib_add_trace (vm, node, b0, sizeof (*t));
 305               t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 306               t->next_index = next0;
 307             }
 308
 309           pkts_processed += next0 != NAT64_OUT2IN_NEXT_DROP;
 310
 311           /* verify speculative enqueue, maybe switch current next frame */
 312           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 313                                            n_left_to_next, bi0, next0);
 314         }
 315       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 316     }
 317   vlib_node_increment_counter (vm, nat64_out2in_node.index,
 318                                NAT64_OUT2IN_ERROR_OUT2IN_PACKETS,
 319                                pkts_processed);
 320   return frame->n_vectors;
 321 }
 322
 323 /* *INDENT-OFF* */
 324 VLIB_REGISTER_NODE (nat64_out2in_node) = {
 325   .function = nat64_out2in_node_fn,
 326   .name = "nat64-out2in",
 327   .vector_size = sizeof (u32),
 328   .format_trace = format_nat64_out2in_trace,
 329   .type = VLIB_NODE_TYPE_INTERNAL,
 330   .n_errors = ARRAY_LEN (nat64_out2in_error_strings),
 331   .error_strings = nat64_out2in_error_strings,.n_next_nodes = 2,
 332   /* edit / add dispositions here */
 333   .next_nodes = {
 334     [NAT64_OUT2IN_NEXT_DROP] = "error-drop",
 335     [NAT64_OUT2IN_NEXT_LOOKUP] = "ip6-lookup",
 336   },
 337 };
 338 /* *INDENT-ON* */
 339
 340 VLIB_NODE_FUNCTION_MULTIARCH (nat64_out2in_node, nat64_out2in_node_fn);
 341
 342 /*
 343  * fd.io coding-style-patch-verification: ON
 344  *
 345  * Local Variables:
 346  * eval: (c-set-style "gnu")
 347  * End:
 348  */