src/plugins/nat/nat44_hairpinning.c

   1 /*
   2  * Copyright (c) 2018 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 NAT44 hairpinning
  18  */
  19
  20 #include <vlib/vlib.h>
  21 #include <vnet/vnet.h>
  22 #include <vnet/fib/ip4_fib.h>
  23 #include <nat/nat.h>
  24 #include <nat/nat_inlines.h>
  25
  26 typedef enum
  27 {
  28   SNAT_HAIRPIN_SRC_NEXT_DROP,
  29   SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT,
  30   SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT_WH,
  31   SNAT_HAIRPIN_SRC_NEXT_INTERFACE_OUTPUT,
  32   SNAT_HAIRPIN_SRC_N_NEXT,
  33 } snat_hairpin_src_next_t;
  34
  35 typedef enum
  36 {
  37   NAT_HAIRPIN_NEXT_LOOKUP,
  38   NAT_HAIRPIN_NEXT_DROP,
  39   NAT_HAIRPIN_N_NEXT,
  40 } nat_hairpin_next_t;
  41
  42 typedef struct
  43 {
  44   ip4_address_t addr;
  45   u16 port;
  46   u32 fib_index;
  47   u32 session_index;
  48 } nat_hairpin_trace_t;
  49
  50 static u8 *
  51 format_nat_hairpin_trace (u8 * s, va_list * args)
  52 {
  53   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  54   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  55   nat_hairpin_trace_t *t = va_arg (*args, nat_hairpin_trace_t *);
  56
  57   s =
  58     format (s, "new dst addr %U port %u fib-index %u", format_ip4_address,
  59             &t->addr, clib_net_to_host_u16 (t->port), t->fib_index);
  60   if (~0 == t->session_index)
  61     {
  62       s = format (s, " is-static-mapping");
  63     }
  64   else
  65     {
  66       s = format (s, " session-index %u", t->session_index);
  67     }
  68
  69   return s;
  70 }
  71
  72 extern vnet_feature_arc_registration_t vnet_feat_arc_ip4_local;
  73
  74 static_always_inline int
  75 is_hairpinning (snat_main_t * sm, ip4_address_t * dst_addr)
  76 {
  77   snat_address_t *ap;
  78   clib_bihash_kv_8_8_t kv, value;
  79
  80   /* *INDENT-OFF* */
  81   vec_foreach (ap, sm->addresses)
  82     {
  83       if (ap->addr.as_u32 == dst_addr->as_u32)
  84         return 1;
  85     }
  86   /* *INDENT-ON* */
  87
  88   init_nat_k (&kv, *dst_addr, 0, 0, 0);
  89   if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
  90     return 1;
  91
  92   return 0;
  93 }
  94
  95 #ifndef CLIB_MARCH_VARIANT
  96 int
  97 snat_hairpinning (vlib_main_t *vm, vlib_node_runtime_t *node, snat_main_t *sm,
  98                   vlib_buffer_t *b0, ip4_header_t *ip0, udp_header_t *udp0,
  99                   tcp_header_t *tcp0, u32 proto0, int do_trace)
 100 {
 101   snat_session_t *s0 = NULL;
 102   clib_bihash_kv_8_8_t kv0, value0;
 103   ip_csum_t sum0;
 104   u32 new_dst_addr0 = 0, old_dst_addr0, ti = 0, si = ~0;
 105   u16 new_dst_port0 = ~0, old_dst_port0;
 106   int rv;
 107   ip4_address_t sm0_addr;
 108   u16 sm0_port;
 109   u32 sm0_fib_index;
 110   u32 old_sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_TX];
 111   /* Check if destination is static mappings */
 112   if (!snat_static_mapping_match
 113       (sm, ip0->dst_address, udp0->dst_port, sm->outside_fib_index, proto0,
 114        &sm0_addr, &sm0_port, &sm0_fib_index, 1, 0, 0, 0, 0, 0, 0))
 115     {
 116       new_dst_addr0 = sm0_addr.as_u32;
 117       new_dst_port0 = sm0_port;
 118       vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0_fib_index;
 119     }
 120   /* or active session */
 121   else
 122     {
 123       if (sm->num_workers > 1)
 124         ti =
 125           (clib_net_to_host_u16 (udp0->dst_port) -
 126            1024) / sm->port_per_thread;
 127       else
 128         ti = sm->num_workers;
 129
 130       init_nat_k (&kv0, ip0->dst_address, udp0->dst_port,
 131                   sm->outside_fib_index, proto0);
 132       rv = clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0);
 133       if (rv)
 134         {
 135           rv = 0;
 136           goto trace;
 137         }
 138
 139       si = nat_value_get_session_index (&value0);
 140       s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
 141       new_dst_addr0 = s0->in2out.addr.as_u32;
 142       new_dst_port0 = s0->in2out.port;
 143       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 144     }
 145
 146   /* Check if anything has changed and if not, then return 0. This
 147      helps avoid infinite loop, repeating the three nodes
 148      nat44-hairpinning-->ip4-lookup-->ip4-local, in case nothing has
 149      changed. */
 150   old_dst_addr0 = ip0->dst_address.as_u32;
 151   old_dst_port0 = tcp0->dst;
 152   if (new_dst_addr0 == old_dst_addr0
 153       && new_dst_port0 == old_dst_port0
 154       && vnet_buffer (b0)->sw_if_index[VLIB_TX] == old_sw_if_index)
 155     return 0;
 156
 157   /* Destination is behind the same NAT, use internal address and port */
 158   if (new_dst_addr0)
 159     {
 160       old_dst_addr0 = ip0->dst_address.as_u32;
 161       ip0->dst_address.as_u32 = new_dst_addr0;
 162       sum0 = ip0->checksum;
 163       sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
 164                              ip4_header_t, dst_address);
 165       ip0->checksum = ip_csum_fold (sum0);
 166
 167       old_dst_port0 = tcp0->dst;
 168       if (PREDICT_TRUE (new_dst_port0 != old_dst_port0))
 169         {
 170           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 171             {
 172               tcp0->dst = new_dst_port0;
 173               sum0 = tcp0->checksum;
 174               sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
 175                                      ip4_header_t, dst_address);
 176               sum0 = ip_csum_update (sum0, old_dst_port0, new_dst_port0,
 177                                      ip4_header_t /* cheat */ , length);
 178               tcp0->checksum = ip_csum_fold (sum0);
 179             }
 180           else
 181             {
 182               udp0->dst_port = new_dst_port0;
 183               udp0->checksum = 0;
 184             }
 185         }
 186       else
 187         {
 188           if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
 189             {
 190               sum0 = tcp0->checksum;
 191               sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
 192                                      ip4_header_t, dst_address);
 193               tcp0->checksum = ip_csum_fold (sum0);
 194             }
 195         }
 196       rv = 1;
 197       goto trace;
 198     }
 199   rv = 0;
 200 trace:
 201   if (do_trace && PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 202                                  && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 203     {
 204       nat_hairpin_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
 205       t->addr.as_u32 = new_dst_addr0;
 206       t->port = new_dst_port0;
 207       t->fib_index = vnet_buffer (b0)->sw_if_index[VLIB_TX];
 208       if (s0)
 209         {
 210           t->session_index = si;
 211         }
 212       else
 213         {
 214           t->session_index = ~0;
 215         }
 216     }
 217   return rv;
 218 }
 219 #endif
 220
 221 #ifndef CLIB_MARCH_VARIANT
 222 u32
 223 snat_icmp_hairpinning (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
 224                        icmp46_header_t *icmp0)
 225 {
 226   clib_bihash_kv_8_8_t kv0, value0;
 227   u32 old_dst_addr0, new_dst_addr0;
 228   u32 old_addr0, new_addr0;
 229   u16 old_port0, new_port0;
 230   u16 old_checksum0, new_checksum0;
 231   u32 si, ti = 0;
 232   ip_csum_t sum0;
 233   snat_session_t *s0;
 234   snat_static_mapping_t *m0;
 235
 236   if (icmp_type_is_error_message
 237       (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags))
 238     {
 239       ip4_header_t *inner_ip0 = 0;
 240       tcp_udp_header_t *l4_header = 0;
 241
 242       inner_ip0 = (ip4_header_t *) ((icmp_echo_header_t *) (icmp0 + 1) + 1);
 243       l4_header = ip4_next_header (inner_ip0);
 244       u32 protocol = ip_proto_to_nat_proto (inner_ip0->protocol);
 245
 246       if (protocol != NAT_PROTOCOL_TCP && protocol != NAT_PROTOCOL_UDP)
 247         return 1;
 248
 249       init_nat_k (&kv0, ip0->dst_address, l4_header->src_port,
 250                   sm->outside_fib_index, protocol);
 251       if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
 252         return 1;
 253       si = nat_value_get_session_index (&value0);
 254       s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
 255       new_dst_addr0 = s0->in2out.addr.as_u32;
 256       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 257
 258       /* update inner source IP address */
 259       old_addr0 = inner_ip0->src_address.as_u32;
 260       inner_ip0->src_address.as_u32 = new_dst_addr0;
 261       new_addr0 = inner_ip0->src_address.as_u32;
 262       sum0 = icmp0->checksum;
 263       sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 264                              src_address);
 265       icmp0->checksum = ip_csum_fold (sum0);
 266
 267       /* update inner IP header checksum */
 268       old_checksum0 = inner_ip0->checksum;
 269       sum0 = inner_ip0->checksum;
 270       sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 271                              src_address);
 272       inner_ip0->checksum = ip_csum_fold (sum0);
 273       new_checksum0 = inner_ip0->checksum;
 274       sum0 = icmp0->checksum;
 275       sum0 = ip_csum_update (sum0, old_checksum0, new_checksum0, ip4_header_t,
 276                              checksum);
 277       icmp0->checksum = ip_csum_fold (sum0);
 278
 279       /* update inner source port */
 280       old_port0 = l4_header->src_port;
 281       l4_header->src_port = s0->in2out.port;
 282       new_port0 = l4_header->src_port;
 283       sum0 = icmp0->checksum;
 284       sum0 = ip_csum_update (sum0, old_port0, new_port0, tcp_udp_header_t,
 285                              src_port);
 286       icmp0->checksum = ip_csum_fold (sum0);
 287     }
 288   else
 289     {
 290       init_nat_k (&kv0, ip0->dst_address, 0, sm->outside_fib_index, 0);
 291       if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv0,
 292                                   &value0))
 293         {
 294           icmp_echo_header_t *echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 295           u16 icmp_id0 = echo0->identifier;
 296           init_nat_k (&kv0, ip0->dst_address, icmp_id0, sm->outside_fib_index,
 297                       NAT_PROTOCOL_ICMP);
 298           if (sm->num_workers > 1)
 299             ti =
 300               (clib_net_to_host_u16 (icmp_id0) - 1024) / sm->port_per_thread;
 301           else
 302             ti = sm->num_workers;
 303           int rv = clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0);
 304           if (!rv)
 305             {
 306               si = nat_value_get_session_index (&value0);
 307               s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
 308               new_dst_addr0 = s0->in2out.addr.as_u32;
 309               vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 310               echo0->identifier = s0->in2out.port;
 311               sum0 = icmp0->checksum;
 312               sum0 = ip_csum_update (sum0, icmp_id0, s0->in2out.port,
 313                                      icmp_echo_header_t, identifier);
 314               icmp0->checksum = ip_csum_fold (sum0);
 315               goto change_addr;
 316             }
 317
 318           return 1;
 319         }
 320
 321       m0 = pool_elt_at_index (sm->static_mappings, value0.value);
 322
 323       new_dst_addr0 = m0->local_addr.as_u32;
 324       if (vnet_buffer (b0)->sw_if_index[VLIB_TX] == ~0)
 325         vnet_buffer (b0)->sw_if_index[VLIB_TX] = m0->fib_index;
 326     }
 327 change_addr:
 328   /* Destination is behind the same NAT, use internal address and port */
 329   if (new_dst_addr0)
 330     {
 331       old_dst_addr0 = ip0->dst_address.as_u32;
 332       ip0->dst_address.as_u32 = new_dst_addr0;
 333       sum0 = ip0->checksum;
 334       sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
 335                              ip4_header_t, dst_address);
 336       ip0->checksum = ip_csum_fold (sum0);
 337     }
 338   return 0;
 339 }
 340 #endif
 341
 342 #ifndef CLIB_MARCH_VARIANT
 343 void
 344 nat_hairpinning_sm_unknown_proto (snat_main_t * sm,
 345                                   vlib_buffer_t * b, ip4_header_t * ip)
 346 {
 347   clib_bihash_kv_8_8_t kv, value;
 348   snat_static_mapping_t *m;
 349   u32 old_addr, new_addr;
 350   ip_csum_t sum;
 351
 352   init_nat_k (&kv, ip->dst_address, 0, 0, 0);
 353   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
 354     return;
 355
 356   m = pool_elt_at_index (sm->static_mappings, value.value);
 357
 358   old_addr = ip->dst_address.as_u32;
 359   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
 360   sum = ip->checksum;
 361   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
 362   ip->checksum = ip_csum_fold (sum);
 363
 364   if (vnet_buffer (b)->sw_if_index[VLIB_TX] == ~0)
 365     vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
 366 }
 367 #endif
 368
 369 static inline uword
 370 nat44_hairpinning_fn_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 371                              vlib_frame_t *frame)
 372 {
 373   u32 n_left_from, *from, *to_next;
 374   nat_hairpin_next_t next_index;
 375   snat_main_t *sm = &snat_main;
 376   vnet_feature_main_t *fm = &feature_main;
 377   u8 arc_index = vnet_feat_arc_ip4_local.feature_arc_index;
 378   vnet_feature_config_main_t *cm = &fm->feature_config_mains[arc_index];
 379
 380   from = vlib_frame_vector_args (frame);
 381   n_left_from = frame->n_vectors;
 382   next_index = node->cached_next_index;
 383
 384   while (n_left_from > 0)
 385     {
 386       u32 n_left_to_next;
 387
 388       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 389
 390       while (n_left_from > 0 && n_left_to_next > 0)
 391         {
 392           u32 bi0;
 393           vlib_buffer_t *b0;
 394           u32 next0;
 395           ip4_header_t *ip0;
 396           u32 proto0;
 397           udp_header_t *udp0;
 398           tcp_header_t *tcp0;
 399           u32 sw_if_index0;
 400
 401           /* speculatively enqueue b0 to the current next frame */
 402           bi0 = from[0];
 403           to_next[0] = bi0;
 404           from += 1;
 405           to_next += 1;
 406           n_left_from -= 1;
 407           n_left_to_next -= 1;
 408
 409           b0 = vlib_get_buffer (vm, bi0);
 410           ip0 = vlib_buffer_get_current (b0);
 411           udp0 = ip4_next_header (ip0);
 412           tcp0 = (tcp_header_t *) udp0;
 413           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 414
 415           proto0 = ip_proto_to_nat_proto (ip0->protocol);
 416
 417           vnet_get_config_data (&cm->config_main, &b0->current_config_index,
 418                                 &next0, 0);
 419
 420           if (snat_hairpinning (vm, node, sm, b0, ip0, udp0, tcp0, proto0,
 421                                 1 /* do_trace */))
 422             next0 = NAT_HAIRPIN_NEXT_LOOKUP;
 423
 424           if (next0 != NAT_HAIRPIN_NEXT_DROP)
 425             {
 426               vlib_increment_simple_counter (&sm->counters.hairpinning,
 427                                              vm->thread_index, sw_if_index0,
 428                                              1);
 429             }
 430
 431           /* verify speculative enqueue, maybe switch current next frame */
 432           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 433                                            to_next, n_left_to_next,
 434                                            bi0, next0);
 435         }
 436
 437       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 438     }
 439
 440   return frame->n_vectors;
 441 }
 442
 443 VLIB_NODE_FN (nat44_hairpinning_node) (vlib_main_t * vm,
 444                                        vlib_node_runtime_t * node,
 445                                        vlib_frame_t * frame)
 446 {
 447   return nat44_hairpinning_fn_inline (vm, node, frame);
 448 }
 449
 450 /* *INDENT-OFF* */
 451 VLIB_REGISTER_NODE (nat44_hairpinning_node) = {
 452   .name = "nat44-hairpinning",
 453   .vector_size = sizeof (u32),
 454   .type = VLIB_NODE_TYPE_INTERNAL,
 455   .format_trace = format_nat_hairpin_trace,
 456   .n_next_nodes = NAT_HAIRPIN_N_NEXT,
 457   .next_nodes = {
 458     [NAT_HAIRPIN_NEXT_DROP] = "error-drop",
 459     [NAT_HAIRPIN_NEXT_LOOKUP] = "ip4-lookup",
 460   },
 461 };
 462 /* *INDENT-ON* */
 463
 464 static inline uword
 465 snat_hairpin_dst_fn_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 466                             vlib_frame_t *frame)
 467 {
 468   u32 n_left_from, *from, *to_next;
 469   nat_hairpin_next_t next_index;
 470   snat_main_t *sm = &snat_main;
 471
 472   from = vlib_frame_vector_args (frame);
 473   n_left_from = frame->n_vectors;
 474   next_index = node->cached_next_index;
 475
 476   while (n_left_from > 0)
 477     {
 478       u32 n_left_to_next;
 479
 480       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 481
 482       while (n_left_from > 0 && n_left_to_next > 0)
 483         {
 484           u32 bi0;
 485           vlib_buffer_t *b0;
 486           u32 next0;
 487           ip4_header_t *ip0;
 488           u32 proto0;
 489           u32 sw_if_index0;
 490
 491           /* speculatively enqueue b0 to the current next frame */
 492           bi0 = from[0];
 493           to_next[0] = bi0;
 494           from += 1;
 495           to_next += 1;
 496           n_left_from -= 1;
 497           n_left_to_next -= 1;
 498
 499           b0 = vlib_get_buffer (vm, bi0);
 500           next0 = NAT_HAIRPIN_NEXT_LOOKUP;
 501           ip0 = vlib_buffer_get_current (b0);
 502           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 503
 504           proto0 = ip_proto_to_nat_proto (ip0->protocol);
 505
 506           vnet_buffer (b0)->snat.flags = 0;
 507           if (PREDICT_FALSE (is_hairpinning (sm, &ip0->dst_address)))
 508             {
 509               if (proto0 == NAT_PROTOCOL_TCP || proto0 == NAT_PROTOCOL_UDP)
 510                 {
 511                   udp_header_t *udp0 = ip4_next_header (ip0);
 512                   tcp_header_t *tcp0 = (tcp_header_t *) udp0;
 513
 514                   snat_hairpinning (vm, node, sm, b0, ip0, udp0, tcp0, proto0,
 515                                     1 /* do_trace */);
 516                 }
 517               else if (proto0 == NAT_PROTOCOL_ICMP)
 518                 {
 519                   icmp46_header_t *icmp0 = ip4_next_header (ip0);
 520
 521                   snat_icmp_hairpinning (sm, b0, ip0, icmp0);
 522                 }
 523               else
 524                 {
 525                   nat_hairpinning_sm_unknown_proto (sm, b0, ip0);
 526                 }
 527
 528               vnet_buffer (b0)->snat.flags = SNAT_FLAG_HAIRPINNING;
 529             }
 530
 531
 532           if (next0 != NAT_HAIRPIN_NEXT_DROP)
 533             {
 534               vlib_increment_simple_counter (&sm->counters.hairpinning,
 535                                              vm->thread_index, sw_if_index0,
 536                                              1);
 537             }
 538
 539           /* verify speculative enqueue, maybe switch current next frame */
 540           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 541                                            to_next, n_left_to_next,
 542                                            bi0, next0);
 543         }
 544
 545       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 546     }
 547
 548   return frame->n_vectors;
 549 }
 550
 551 VLIB_NODE_FN (snat_hairpin_dst_node) (vlib_main_t * vm,
 552                                       vlib_node_runtime_t * node,
 553                                       vlib_frame_t * frame)
 554 {
 555   return snat_hairpin_dst_fn_inline (vm, node, frame);
 556 }
 557
 558 /* *INDENT-OFF* */
 559 VLIB_REGISTER_NODE (snat_hairpin_dst_node) = {
 560   .name = "nat44-hairpin-dst",
 561   .vector_size = sizeof (u32),
 562   .type = VLIB_NODE_TYPE_INTERNAL,
 563   .format_trace = format_nat_hairpin_trace,
 564   .n_next_nodes = NAT_HAIRPIN_N_NEXT,
 565   .next_nodes = {
 566     [NAT_HAIRPIN_NEXT_DROP] = "error-drop",
 567     [NAT_HAIRPIN_NEXT_LOOKUP] = "ip4-lookup",
 568   },
 569 };
 570 /* *INDENT-ON* */
 571
 572 static inline uword
 573 snat_hairpin_src_fn_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 574                             vlib_frame_t *frame)
 575 {
 576   u32 n_left_from, *from, *to_next;
 577   snat_hairpin_src_next_t next_index;
 578   snat_main_t *sm = &snat_main;
 579
 580   from = vlib_frame_vector_args (frame);
 581   n_left_from = frame->n_vectors;
 582   next_index = node->cached_next_index;
 583
 584   while (n_left_from > 0)
 585     {
 586       u32 n_left_to_next;
 587
 588       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 589
 590       while (n_left_from > 0 && n_left_to_next > 0)
 591         {
 592           u32 bi0;
 593           vlib_buffer_t *b0;
 594           u32 next0;
 595           snat_interface_t *i;
 596           u32 sw_if_index0;
 597
 598           /* speculatively enqueue b0 to the current next frame */
 599           bi0 = from[0];
 600           to_next[0] = bi0;
 601           from += 1;
 602           to_next += 1;
 603           n_left_from -= 1;
 604           n_left_to_next -= 1;
 605
 606           b0 = vlib_get_buffer (vm, bi0);
 607           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 608           vnet_feature_next (&next0, b0);
 609
 610           /* *INDENT-OFF* */
 611           pool_foreach (i, sm->output_feature_interfaces)
 612            {
 613             /* Only packets from NAT inside interface */
 614             if ((nat_interface_is_inside(i)) && (sw_if_index0 == i->sw_if_index))
 615               {
 616                 if (PREDICT_FALSE ((vnet_buffer (b0)->snat.flags) &
 617                                     SNAT_FLAG_HAIRPINNING))
 618                   {
 619                     if (PREDICT_TRUE (sm->num_workers > 1))
 620                       next0 = SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT_WH;
 621                     else
 622                       next0 = SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT;
 623                   }
 624                 break;
 625               }
 626           }
 627           /* *INDENT-ON* */
 628
 629           if (next0 != SNAT_HAIRPIN_SRC_NEXT_DROP)
 630             {
 631               vlib_increment_simple_counter (&sm->counters.hairpinning,
 632                                              vm->thread_index, sw_if_index0,
 633                                              1);
 634             }
 635
 636           /* verify speculative enqueue, maybe switch current next frame */
 637           vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 638                                            to_next, n_left_to_next,
 639                                            bi0, next0);
 640         }
 641
 642       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 643     }
 644
 645   return frame->n_vectors;
 646 }
 647
 648 VLIB_NODE_FN (snat_hairpin_src_node) (vlib_main_t * vm,
 649                                       vlib_node_runtime_t * node,
 650                                       vlib_frame_t * frame)
 651 {
 652   return snat_hairpin_src_fn_inline (vm, node, frame);
 653 }
 654
 655 /* *INDENT-OFF* */
 656 VLIB_REGISTER_NODE (snat_hairpin_src_node) = {
 657   .name = "nat44-hairpin-src",
 658   .vector_size = sizeof (u32),
 659   .type = VLIB_NODE_TYPE_INTERNAL,
 660   .n_next_nodes = SNAT_HAIRPIN_SRC_N_NEXT,
 661   .next_nodes = {
 662      [SNAT_HAIRPIN_SRC_NEXT_DROP] = "error-drop",
 663      [SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT] = "nat44-in2out-output",
 664      [SNAT_HAIRPIN_SRC_NEXT_INTERFACE_OUTPUT] = "interface-output",
 665      [SNAT_HAIRPIN_SRC_NEXT_SNAT_IN2OUT_WH] = "nat44-in2out-output-worker-handoff",
 666   },
 667 };
 668 /* *INDENT-ON* */
 669
 670 /*
 671  * fd.io coding-style-patch-verification: ON
 672  *
 673  * Local Variables:
 674  * eval: (c-set-style "gnu")
 675  * End:
 676  */