src/plugins/nat/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.h>
  16 #include <nat/nat_inlines.h>
  17
  18 typedef enum
  19 {
  20   DSLITE_OUT2IN_NEXT_IP4_LOOKUP,
  21   DSLITE_OUT2IN_NEXT_IP6_LOOKUP,
  22   DSLITE_OUT2IN_NEXT_DROP,
  23   DSLITE_OUT2IN_N_NEXT,
  24 } dslite_out2in_next_t;
  25
  26 static char *dslite_out2in_error_strings[] = {
  27 #define _(sym,string) string,
  28   foreach_dslite_error
  29 #undef _
  30 };
  31
  32 static inline u32
  33 dslite_icmp_out2in (dslite_main_t * dm, ip4_header_t * ip4,
  34                     dslite_session_t ** sp, u32 next, u8 * error,
  35                     u32 thread_index)
  36 {
  37   dslite_session_t *s = 0;
  38   icmp46_header_t *icmp = ip4_next_header (ip4);
  39   clib_bihash_kv_8_8_t kv, value;
  40   snat_session_key_t key;
  41   u32 n = next;
  42   icmp_echo_header_t *echo;
  43   u32 new_addr, old_addr;
  44   u16 old_id, new_id;
  45   ip_csum_t sum;
  46
  47   echo = (icmp_echo_header_t *) (icmp + 1);
  48
  49   if (icmp_type_is_error_message (icmp->type)
  50       || (icmp->type != ICMP4_echo_reply))
  51     {
  52       n = DSLITE_OUT2IN_NEXT_DROP;
  53       *error = DSLITE_ERROR_BAD_ICMP_TYPE;
  54       goto done;
  55     }
  56
  57   key.addr = ip4->dst_address;
  58   key.port = echo->identifier;
  59   key.protocol = SNAT_PROTOCOL_ICMP;
  60   key.fib_index = 0;
  61   kv.key = key.as_u64;
  62
  63   if (clib_bihash_search_8_8
  64       (&dm->per_thread_data[thread_index].out2in, &kv, &value))
  65     {
  66       next = DSLITE_OUT2IN_NEXT_DROP;
  67       *error = DSLITE_ERROR_NO_TRANSLATION;
  68       goto done;
  69     }
  70   else
  71     {
  72       s =
  73         pool_elt_at_index (dm->per_thread_data[thread_index].sessions,
  74                            value.value);
  75     }
  76
  77   old_id = echo->identifier;
  78   echo->identifier = new_id = s->in2out.port;
  79   sum = icmp->checksum;
  80   sum = ip_csum_update (sum, old_id, new_id, icmp_echo_header_t, identifier);
  81   icmp->checksum = ip_csum_fold (sum);
  82
  83   old_addr = ip4->dst_address.as_u32;
  84   ip4->dst_address = s->in2out.addr;
  85   new_addr = ip4->dst_address.as_u32;
  86
  87   sum = ip4->checksum;
  88   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
  89   ip4->checksum = ip_csum_fold (sum);
  90
  91 done:
  92   *sp = s;
  93   return n;
  94 }
  95
  96 VLIB_NODE_FN (dslite_out2in_node) (vlib_main_t * vm,
  97                                    vlib_node_runtime_t * node,
  98                                    vlib_frame_t * frame)
  99 {
 100   u32 n_left_from, *from, *to_next;
 101   dslite_out2in_next_t next_index;
 102   vlib_node_runtime_t *error_node;
 103   u32 thread_index = vm->thread_index;
 104   f64 now = vlib_time_now (vm);
 105   dslite_main_t *dm = &dslite_main;
 106
 107   error_node = vlib_node_get_runtime (vm, dm->dslite_out2in_node_index);
 108
 109   from = vlib_frame_vector_args (frame);
 110   n_left_from = frame->n_vectors;
 111   next_index = node->cached_next_index;
 112
 113
 114   while (n_left_from > 0)
 115     {
 116       u32 n_left_to_next;
 117
 118       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 119
 120       while (n_left_from > 0 && n_left_to_next > 0)
 121         {
 122           u32 bi0;
 123           vlib_buffer_t *b0;
 124           u32 next0 = DSLITE_OUT2IN_NEXT_IP6_LOOKUP;
 125           u8 error0 = DSLITE_ERROR_OUT2IN;
 126           ip4_header_t *ip40;
 127           ip6_header_t *ip60;
 128           u32 proto0;
 129           udp_header_t *udp0;
 130           tcp_header_t *tcp0;
 131           clib_bihash_kv_8_8_t kv0, value0;
 132           snat_session_key_t key0;
 133           dslite_session_t *s0 = 0;
 134           ip_csum_t sum0;
 135           u32 new_addr0, old_addr0;
 136           u16 new_port0, old_port0;
 137
 138           /* speculatively enqueue b0 to the current next frame */
 139           bi0 = from[0];
 140           to_next[0] = bi0;
 141           from += 1;
 142           to_next += 1;
 143           n_left_from -= 1;
 144           n_left_to_next -= 1;
 145
 146           b0 = vlib_get_buffer (vm, bi0);
 147           ip40 = vlib_buffer_get_current (b0);
 148           proto0 = ip_proto_to_snat_proto (ip40->protocol);
 149
 150           if (PREDICT_FALSE (proto0 == ~0))
 151             {
 152               error0 = DSLITE_ERROR_UNSUPPORTED_PROTOCOL;
 153               next0 = DSLITE_OUT2IN_NEXT_DROP;
 154               goto trace0;
 155             }
 156
 157           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
 158             {
 159               next0 =
 160                 dslite_icmp_out2in (dm, ip40, &s0, next0, &error0,
 161                                     thread_index);
 162               if (PREDICT_FALSE (next0 == DSLITE_OUT2IN_NEXT_DROP))
 163                 goto trace0;
 164
 165               goto encap0;
 166             }
 167
 168           udp0 = ip4_next_header (ip40);
 169           tcp0 = (tcp_header_t *) udp0;
 170
 171           key0.addr = ip40->dst_address;
 172           key0.port = udp0->dst_port;
 173           key0.protocol = proto0;
 174           key0.fib_index = 0;
 175           kv0.key = key0.as_u64;
 176
 177           if (clib_bihash_search_8_8
 178               (&dm->per_thread_data[thread_index].out2in, &kv0, &value0))
 179             {
 180               next0 = DSLITE_OUT2IN_NEXT_DROP;
 181               error0 = DSLITE_ERROR_NO_TRANSLATION;
 182               goto trace0;
 183             }
 184           else
 185             {
 186               s0 =
 187                 pool_elt_at_index (dm->per_thread_data[thread_index].sessions,
 188                                    value0.value);
 189             }
 190
 191           old_addr0 = ip40->dst_address.as_u32;
 192           ip40->dst_address = s0->in2out.addr;
 193           new_addr0 = ip40->dst_address.as_u32;
 194
 195           sum0 = ip40->checksum;
 196           sum0 =
 197             ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 198                             dst_address);
 199           ip40->checksum = ip_csum_fold (sum0);
 200
 201           if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
 202             {
 203               old_port0 = tcp0->dst_port;
 204               tcp0->dst_port = s0->in2out.port;
 205               new_port0 = tcp0->dst_port;
 206
 207               sum0 = tcp0->checksum;
 208               sum0 =
 209                 ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
 210                                 dst_address);
 211               sum0 =
 212                 ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
 213                                 length);
 214               tcp0->checksum = ip_csum_fold (sum0);
 215             }
 216           else
 217             {
 218               old_port0 = udp0->dst_port;
 219               udp0->dst_port = s0->in2out.port;
 220               udp0->checksum = 0;
 221             }
 222
 223         encap0:
 224           /* Construct IPv6 header */
 225           vlib_buffer_advance (b0, -(sizeof (ip6_header_t)));
 226           ip60 = vlib_buffer_get_current (b0);
 227           ip60->ip_version_traffic_class_and_flow_label =
 228             clib_host_to_net_u32 ((6 << 28) + (ip40->tos << 20));
 229           ip60->payload_length = ip40->length;
 230           ip60->protocol = IP_PROTOCOL_IP_IN_IP;
 231           ip60->hop_limit = ip40->ttl;
 232           ip60->src_address.as_u64[0] = dm->aftr_ip6_addr.as_u64[0];
 233           ip60->src_address.as_u64[1] = dm->aftr_ip6_addr.as_u64[1];
 234           ip60->dst_address.as_u64[0] = s0->in2out.softwire_id.as_u64[0];
 235           ip60->dst_address.as_u64[1] = s0->in2out.softwire_id.as_u64[1];
 236
 237           /* Accounting */
 238           s0->last_heard = now;
 239           s0->total_pkts++;
 240           s0->total_bytes += vlib_buffer_length_in_chain (vm, b0);
 241           /* Per-B4 LRU list maintenance */
 242           clib_dlist_remove (dm->per_thread_data[thread_index].list_pool,
 243                              s0->per_b4_index);
 244           clib_dlist_addtail (dm->per_thread_data[thread_index].list_pool,
 245                               s0->per_b4_list_head_index, s0->per_b4_index);
 246         trace0:
 247           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 248                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 249             {
 250               dslite_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
 251               t->next_index = next0;
 252               t->session_index = ~0;
 253               if (s0)
 254                 t->session_index =
 255                   s0 - dm->per_thread_data[thread_index].sessions;
 256             }
 257
 258           b0->error = error_node->errors[error0];
 259
 260           /* verify speculative enqueue, maybe switch current next frame */
 261           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 262                                            n_left_to_next, bi0, next0);
 263         }
 264       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 265     }
 266
 267   return frame->n_vectors;
 268 }
 269
 270 /* *INDENT-OFF* */
 271 VLIB_REGISTER_NODE (dslite_out2in_node) = {
 272   .name = "dslite-out2in",
 273   .vector_size = sizeof (u32),
 274   .format_trace = format_dslite_trace,
 275   .type = VLIB_NODE_TYPE_INTERNAL,
 276   .n_errors = ARRAY_LEN (dslite_out2in_error_strings),
 277   .error_strings = dslite_out2in_error_strings,
 278   .n_next_nodes = DSLITE_OUT2IN_N_NEXT,
 279   /* edit / add dispositions here */
 280   .next_nodes = {
 281     [DSLITE_OUT2IN_NEXT_DROP] = "error-drop",
 282     [DSLITE_OUT2IN_NEXT_IP4_LOOKUP] = "ip4-lookup",
 283     [DSLITE_OUT2IN_NEXT_IP6_LOOKUP] = "ip6-lookup",
 284   },
 285 };
 286 /* *INDENT-ON* */
 287
 288 /*
 289  * fd.io coding-style-patch-verification: ON
 290  *
 291  * Local Variables:
 292  * eval: (c-set-style "gnu")
 293  * End:
 294  */