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 vlib_node_registration_t nat66_out2in_node;
  45
  46 #define foreach_nat66_out2in_error                       \
  47 _(OUT2IN_PACKETS, "good out2in packets processed")       \
  48 _(NO_TRANSLATION, "no translation")                      \
  49 _(UNKNOWN, "unknown")
  50
  51 typedef enum
  52 {
  53 #define _(sym,str) NAT66_OUT2IN_ERROR_##sym,
  54   foreach_nat66_out2in_error
  55 #undef _
  56     NAT66_OUT2IN_N_ERROR,
  57 } nat66_out2in_error_t;
  58
  59 static char *nat66_out2in_error_strings[] = {
  60 #define _(sym,string) string,
  61   foreach_nat66_out2in_error
  62 #undef _
  63 };
  64
  65 typedef enum
  66 {
  67   NAT66_OUT2IN_NEXT_IP6_LOOKUP,
  68   NAT66_OUT2IN_NEXT_DROP,
  69   NAT66_OUT2IN_N_NEXT,
  70 } nat66_out2in_next_t;
  71
  72 static inline uword
  73 nat66_out2in_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
  74                       vlib_frame_t * frame)
  75 {
  76   u32 n_left_from, *from, *to_next;
  77   nat66_out2in_next_t next_index;
  78   u32 pkts_processed = 0;
  79   u32 thread_index = vlib_get_thread_index ();
  80   nat66_main_t *nm = &nat66_main;
  81
  82   from = vlib_frame_vector_args (frame);
  83   n_left_from = frame->n_vectors;
  84   next_index = node->cached_next_index;
  85
  86   while (n_left_from > 0)
  87     {
  88       u32 n_left_to_next;
  89
  90       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
  91
  92       while (n_left_from > 0 && n_left_to_next > 0)
  93         {
  94           u32 bi0;
  95           vlib_buffer_t *b0;
  96           u32 next0 = NAT66_OUT2IN_NEXT_IP6_LOOKUP;
  97           ip6_header_t *ip60;
  98           u16 l4_offset0, frag_offset0;
  99           u8 l4_protocol0;
 100           nat66_static_mapping_t *sm0;
 101           u32 sw_if_index0, fib_index0;
 102           udp_header_t *udp0;
 103           tcp_header_t *tcp0;
 104           icmp46_header_t *icmp0;
 105           u16 *checksum0 = 0;
 106           ip_csum_t csum0;
 107
 108           /* speculatively enqueue b0 to the current next frame */
 109           bi0 = from[0];
 110           to_next[0] = bi0;
 111           from += 1;
 112           to_next += 1;
 113           n_left_from -= 1;
 114           n_left_to_next -= 1;
 115
 116           b0 = vlib_get_buffer (vm, bi0);
 117           ip60 = vlib_buffer_get_current (b0);
 118
 119           if (PREDICT_FALSE
 120               (ip6_parse
 121                (ip60, b0->current_length, &l4_protocol0, &l4_offset0,
 122                 &frag_offset0)))
 123             {
 124               next0 = NAT66_OUT2IN_NEXT_DROP;
 125               b0->error = node->errors[NAT66_OUT2IN_ERROR_UNKNOWN];
 126               goto trace0;
 127             }
 128
 129           sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 130           fib_index0 =
 131             fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP6,
 132                                                  sw_if_index0);
 133
 134           sm0 = nat66_static_mapping_get (&ip60->dst_address, fib_index0, 0);
 135           if (PREDICT_FALSE (!sm0))
 136             {
 137               goto trace0;
 138             }
 139
 140           if (l4_protocol0 == IP_PROTOCOL_UDP)
 141             {
 142               udp0 = (udp_header_t *) u8_ptr_add (ip60, l4_offset0);
 143               checksum0 = &udp0->checksum;
 144             }
 145           else if (l4_protocol0 == IP_PROTOCOL_TCP)
 146             {
 147               tcp0 = (tcp_header_t *) u8_ptr_add (ip60, l4_offset0);
 148               checksum0 = &tcp0->checksum;
 149             }
 150           else if (l4_protocol0 == IP_PROTOCOL_ICMP6)
 151             {
 152               icmp0 = (icmp46_header_t *) u8_ptr_add (ip60, l4_offset0);
 153               checksum0 = &icmp0->checksum;
 154             }
 155           else
 156             goto skip_csum0;
 157
 158           csum0 = ip_csum_sub_even (*checksum0, ip60->dst_address.as_u64[0]);
 159           csum0 = ip_csum_sub_even (csum0, ip60->dst_address.as_u64[1]);
 160           csum0 = ip_csum_add_even (csum0, sm0->l_addr.as_u64[0]);
 161           csum0 = ip_csum_add_even (csum0, sm0->l_addr.as_u64[1]);
 162           *checksum0 = ip_csum_fold (csum0);
 163
 164         skip_csum0:
 165           ip60->dst_address.as_u64[0] = sm0->l_addr.as_u64[0];
 166           ip60->dst_address.as_u64[1] = sm0->l_addr.as_u64[1];
 167           vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0->fib_index;
 168
 169           vlib_increment_combined_counter (&nm->session_counters,
 170                                            thread_index, sm0 - nm->sm, 1,
 171                                            vlib_buffer_length_in_chain (vm,
 172                                                                         b0));
 173
 174         trace0:
 175           if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 176                              && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 177             {
 178               nat66_out2in_trace_t *t =
 179                 vlib_add_trace (vm, node, b0, sizeof (*t));
 180               t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
 181               t->next_index = next0;
 182             }
 183
 184           pkts_processed += next0 != NAT66_OUT2IN_NEXT_DROP;
 185
 186           /* verify speculative enqueue, maybe switch current next frame */
 187           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 188                                            n_left_to_next, bi0, next0);
 189         }
 190       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 191     }
 192
 193   vlib_node_increment_counter (vm, nat66_out2in_node.index,
 194                                NAT66_OUT2IN_ERROR_OUT2IN_PACKETS,
 195                                pkts_processed);
 196   return frame->n_vectors;
 197 }
 198
 199 /* *INDENT-OFF* */
 200 VLIB_REGISTER_NODE (nat66_out2in_node) = {
 201   .function = nat66_out2in_node_fn,
 202   .name = "nat66-out2in",
 203   .vector_size = sizeof (u32),
 204   .format_trace = format_nat66_out2in_trace,
 205   .type = VLIB_NODE_TYPE_INTERNAL,
 206   .n_errors = ARRAY_LEN (nat66_out2in_error_strings),
 207   .error_strings = nat66_out2in_error_strings,
 208   .n_next_nodes = NAT66_OUT2IN_N_NEXT,
 209   /* edit / add dispositions here */
 210   .next_nodes = {
 211     [NAT66_OUT2IN_NEXT_DROP] = "error-drop",
 212     [NAT66_OUT2IN_NEXT_IP6_LOOKUP] = "ip6-lookup",
 213   },
 214 };
 215 /* *INDENT-ON* */
 216
 217 VLIB_NODE_FUNCTION_MULTIARCH (nat66_out2in_node, nat66_out2in_node_fn);
 218
 219 /*
 220  * fd.io coding-style-patch-verification: ON
 221  *
 222  * Local Variables:
 223  * eval: (c-set-style "gnu")
 224  * End:
 225  */