src/plugins/nat/nat66_out2in.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 NAT66 outside to inside network translation
  18  */
  19
  20 #include <nat/nat66.h>
  21 #include <vnet/ip/ip6_to_ip4.h>
  22 #include <vnet/fib/fib_table.h>
  23
  24 typedef struct
  25 {
  26   u32 sw_if_index;
  27   u32 next_index;
  28 } nat66_out2in_trace_t;
  29
  30 static u8 *
  31 format_nat66_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   nat66_out2in_trace_t *t = va_arg (*args, nat66_out2in_trace_t *);
  36
  37   s =
  38     format (s, "NAT66-out2in: sw_if_index %d, next index %d", t->sw_if_index,
  39             t->next_index);
  40
  41   return s;
  42 }
  43
  44 #define foreach_nat66_out2in_error                       \
  45 _(OUT2IN_PACKETS, "good out2in packets processed")       \
  46 _(NO_TRANSLATION, "no translation")                      \
  47 _(UNKNOWN, "unknown")
  48
  49 typedef enum
  50 {
  51 #define _(sym,str) NAT66_OUT2IN_ERROR_##sym,
  52   foreach_nat66_out2in_error
  53 #undef _
  54     NAT66_OUT2IN_N_ERROR,
  55 } nat66_out2in_error_t;
  56
  57 static char *nat66_out2in_error_strings[] = {
  58 #define _(sym,string) string,
  59   foreach_nat66_out2in_error
  60 #undef _
  61 };
  62
  63 typedef enum
  64 {
  65   NAT66_OUT2IN_NEXT_IP6_LOOKUP,
  66   NAT66_OUT2IN_NEXT_DROP,
  67   NAT66_OUT2IN_N_NEXT,
  68 } nat66_out2in_next_t;
  69
  70 VLIB_NODE_FN (nat66_out2in_node) (vlib_main_t * vm,
  71                                   vlib_node_runtime_t * node,
  72                                   vlib_frame_t * frame)
  73 {
  74   u32 n_left_from, *from, *to_next;
  75   nat66_out2in_next_t next_index;
  76   u32 pkts_processed = 0;
  77   u32 thread_index = vm->thread_index;
  78   nat66_main_t *nm = &nat66_main;
  79
  80   from = vlib_frame_vector_args (frame);
  81   n_left_from = frame->n_vectors;
  82   next_index = node->cached_next_index;
  83
  84   while (n_left_from > 0)
  85     {
  86       u32 n_left_to_next;
  87
  88       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
  89
  90       while (n_left_from > 0 && n_left_to_next > 0)
  91         {
  92           u32 bi0;
  93           vlib_buffer_t *b0;
  94           u32 next0 = NAT66_OUT2IN_NEXT_IP6_LOOKUP;
  95           ip6_header_t *ip60;
  96           u16 l4_offset0, frag_offset0;
  97           u8 l4_protocol0;
  98           nat66_static_mapping_t *sm0;
  99           u32 sw_if_index0, fib_index0;
 100           udp_header_t *udp0;
 101           tcp_header_t *tcp0;
 102           icmp46_header_t *icmp0;
 103           u16 *checksum0 = 0;
 104           ip_csum_t csum0;
 105
 106           /* speculatively enqueue b0 to the current next frame */
 107           bi0 = from[0];
 108           to_next[0] = bi0;
 109           from += 1;
 110           to_next += 1;
 111           n_left_from -= 1;
 112           n_left_to_next -= 1;
 113
 114           b0 = vlib_get_buffer (vm, bi0);
 115           ip60 = vlib_buffer_get_current (b0);
 116
 117           if (PREDICT_FALSE
 118               (ip6_parse
 119                (vm, b0, ip60, b0->current_length, &l4_protocol0, &l4_offset0,
 120                 &frag_offset0)))
 121             {
 122               next0 = NAT66_OUT2IN_NEXT_DROP;
 123               b0->error = node->errors[NAT66_OUT2IN_ERROR_UNKNOWN];
 124               goto trace0;
 125             }
 126
 127           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 128           fib_index0 =
 129             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6,
 130                                                  sw_if_index0);
 131
 132           sm0 = nat66_static_mapping_get (&ip60->dst_address, fib_index0, 0);
 133           if (PREDICT_FALSE (!sm0))
 134             {
 135               goto trace0;
 136             }
 137
 138           if (l4_protocol0 == IP_PROTOCOL_UDP)
 139             {
 140               udp0 = (udp_header_t *) u8_ptr_add (ip60, l4_offset0);
 141               checksum0 = &udp0->checksum;
 142             }
 143           else if (l4_protocol0 == IP_PROTOCOL_TCP)
 144             {
 145               tcp0 = (tcp_header_t *) u8_ptr_add (ip60, l4_offset0);
 146               checksum0 = &tcp0->checksum;
 147             }
 148           else if (l4_protocol0 == IP_PROTOCOL_ICMP6)
 149             {
 150               icmp0 = (icmp46_header_t *) u8_ptr_add (ip60, l4_offset0);
 151               checksum0 = &icmp0->checksum;
 152             }
 153           else
 154             goto skip_csum0;
 155
 156           csum0 = ip_csum_sub_even (*checksum0, ip60->dst_address.as_u64[0]);
 157           csum0 = ip_csum_sub_even (csum0, ip60->dst_address.as_u64[1]);
 158           csum0 = ip_csum_add_even (csum0, sm0->l_addr.as_u64[0]);
 159           csum0 = ip_csum_add_even (csum0, sm0->l_addr.as_u64[1]);
 160           *checksum0 = ip_csum_fold (csum0);
 161
 162         skip_csum0:
 163           ip60->dst_address.as_u64[0] = sm0->l_addr.as_u64[0];
 164           ip60->dst_address.as_u64[1] = sm0->l_addr.as_u64[1];
 165           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0->fib_index;
 166
 167           vlib_increment_combined_counter (&nm->session_counters,
 168                                            thread_index, sm0 - nm->sm, 1,
 169                                            vlib_buffer_length_in_chain (vm,
 170                                                                         b0));
 171
 172         trace0:
 173           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 174                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 175             {
 176               nat66_out2in_trace_t *t =
 177                 vlib_add_trace (vm, node, b0, sizeof (*t));
 178               t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 179               t->next_index = next0;
 180             }
 181
 182           pkts_processed += next0 != NAT66_OUT2IN_NEXT_DROP;
 183
 184           /* verify speculative enqueue, maybe switch current next frame */
 185           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 186                                            n_left_to_next, bi0, next0);
 187         }
 188       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 189     }
 190
 191   vlib_node_increment_counter (vm, nm->out2in_node_index,
 192                                NAT66_OUT2IN_ERROR_OUT2IN_PACKETS,
 193                                pkts_processed);
 194   return frame->n_vectors;
 195 }
 196
 197 /* *INDENT-OFF* */
 198 VLIB_REGISTER_NODE (nat66_out2in_node) = {
 199   .name = "nat66-out2in",
 200   .vector_size = sizeof (u32),
 201   .format_trace = format_nat66_out2in_trace,
 202   .type = VLIB_NODE_TYPE_INTERNAL,
 203   .n_errors = ARRAY_LEN (nat66_out2in_error_strings),
 204   .error_strings = nat66_out2in_error_strings,
 205   .n_next_nodes = NAT66_OUT2IN_N_NEXT,
 206   /* edit / add dispositions here */
 207   .next_nodes = {
 208     [NAT66_OUT2IN_NEXT_DROP] = "error-drop",
 209     [NAT66_OUT2IN_NEXT_IP6_LOOKUP] = "ip6-lookup",
 210   },
 211 };
 212 /* *INDENT-ON* */
 213
 214 /*
 215  * fd.io coding-style-patch-verification: ON
 216  *
 217  * Local Variables:
 218  * eval: (c-set-style "gnu")
 219  * End:
 220  */