src/vnet/ip-neighbor/ip6_neighbor.c

   1 /*
   2  * ip/ip6_neighbor.c: IP6 neighbor handling
   3  *
   4  * Copyright (c) 2010 Cisco and/or its affiliates.
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at:
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  */
  17
  18 #include <vnet/ip-neighbor/ip6_neighbor.h>
  19 #include <vnet/util/throttle.h>
  20 #include <vnet/fib/fib_sas.h>
  21
  22 /** ND throttling */
  23 static throttle_t nd_throttle;
  24
  25 VLIB_REGISTER_LOG_CLASS (ip6_neighbor_log, static) = {
  26   .class_name = "ip6",
  27   .subclass_name = "neighbor",
  28 };
  29
  30 #define log_debug(fmt, ...)                                                   \
  31   vlib_log_debug (ip6_neighbor_log.class, fmt, __VA_ARGS__)
  32 void
  33 ip6_neighbor_probe_dst (u32 sw_if_index, const ip6_address_t * dst)
  34 {
  35   ip6_address_t src;
  36
  37   if (fib_sas6_get (sw_if_index, dst, &src))
  38     ip6_neighbor_probe (vlib_get_main (), vnet_get_main (),
  39                         sw_if_index, &src, dst);
  40 }
  41
  42 void
  43 ip6_neighbor_advertise (vlib_main_t * vm,
  44                         vnet_main_t * vnm,
  45                         u32 sw_if_index, const ip6_address_t * addr)
  46 {
  47   vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
  48   ip6_main_t *i6m = &ip6_main;
  49   u8 *rewrite, rewrite_len;
  50   u8 dst_address[6];
  51
  52   if (NULL == addr)
  53     addr = ip6_interface_first_address (i6m, sw_if_index);
  54
  55   if (addr)
  56     {
  57       log_debug ("Sending unsolicitated NA IP6 address %U on sw_if_idex %d",
  58                  format_ip6_address, addr, sw_if_index);
  59
  60       /* Form unsolicited neighbor advertisement packet from NS pkt template */
  61       int bogus_length;
  62       u32 bi = 0;
  63       icmp6_neighbor_solicitation_header_t *h =
  64         vlib_packet_template_get_packet (vm,
  65                                          &ip6_neighbor_packet_template,
  66                                          &bi);
  67       if (!h)
  68         return;
  69
  70       ip6_set_reserved_multicast_address (&h->ip.dst_address,
  71                                           IP6_MULTICAST_SCOPE_link_local,
  72                                           IP6_MULTICAST_GROUP_ID_all_hosts);
  73       h->ip.src_address = addr[0];
  74       h->neighbor.icmp.type = ICMP6_neighbor_advertisement;
  75       h->neighbor.target_address = addr[0];
  76       h->neighbor.advertisement_flags = clib_host_to_net_u32
  77         (ICMP6_NEIGHBOR_ADVERTISEMENT_FLAG_OVERRIDE);
  78       h->link_layer_option.header.type =
  79         ICMP6_NEIGHBOR_DISCOVERY_OPTION_target_link_layer_address;
  80       clib_memcpy (h->link_layer_option.ethernet_address,
  81                    hi->hw_address, vec_len (hi->hw_address));
  82       h->neighbor.icmp.checksum =
  83         ip6_tcp_udp_icmp_compute_checksum (vm, 0, &h->ip, &bogus_length);
  84       ASSERT (bogus_length == 0);
  85
  86       /* Setup MAC header with IP6 Etype and mcast DMAC */
  87       vlib_buffer_t *b = vlib_get_buffer (vm, bi);
  88       ip6_multicast_ethernet_address (dst_address,
  89                                       IP6_MULTICAST_GROUP_ID_all_hosts);
  90       rewrite =
  91         ethernet_build_rewrite (vnm, sw_if_index, VNET_LINK_IP6, dst_address);
  92       rewrite_len = vec_len (rewrite);
  93       vlib_buffer_advance (b, -rewrite_len);
  94       ethernet_header_t *e = vlib_buffer_get_current (b);
  95       clib_memcpy (e->dst_address, rewrite, rewrite_len);
  96       vec_free (rewrite);
  97
  98       /* Send unsolicited ND advertisement packet out the specified interface */
  99       vnet_buffer (b)->sw_if_index[VLIB_RX] =
 100         vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;
 101       vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
 102       u32 *to_next = vlib_frame_vector_args (f);
 103       to_next[0] = bi;
 104       f->n_vectors = 1;
 105       vlib_put_frame_to_node (vm, hi->output_node_index, f);
 106     }
 107 }
 108
 109 typedef enum
 110 {
 111   IP6_NBR_NEXT_DROP,
 112   IP6_NBR_NEXT_REPLY_TX,
 113   IP6_NBR_N_NEXT,
 114 } ip6_discover_neighbor_next_t;
 115
 116 typedef enum
 117 {
 118   IP6_NBR_ERROR_DROP,
 119   IP6_NBR_ERROR_REQUEST_SENT,
 120   IP6_NBR_ERROR_NO_SOURCE_ADDRESS,
 121   IP6_NBR_ERROR_NO_BUFFERS,
 122 } ip6_discover_neighbor_error_t;
 123
 124 static uword
 125 ip6_discover_neighbor_inline (vlib_main_t * vm,
 126                               vlib_node_runtime_t * node,
 127                               vlib_frame_t * frame, int is_glean)
 128 {
 129   vnet_main_t *vnm = vnet_get_main ();
 130   u32 *from, *to_next_drop;
 131   uword n_left_from, n_left_to_next_drop;
 132   u64 seed;
 133   u32 thread_index = vm->thread_index;
 134
 135   if (node->flags & VLIB_NODE_FLAG_TRACE)
 136     ip6_forward_next_trace (vm, node, frame, VLIB_TX);
 137
 138   seed = throttle_seed (&nd_throttle, thread_index, vlib_time_now (vm));
 139
 140   from = vlib_frame_vector_args (frame);
 141   n_left_from = frame->n_vectors;
 142
 143   while (n_left_from > 0)
 144     {
 145       vlib_get_next_frame (vm, node, IP6_NBR_NEXT_DROP,
 146                            to_next_drop, n_left_to_next_drop);
 147
 148       while (n_left_from > 0 && n_left_to_next_drop > 0)
 149         {
 150           u32 pi0, adj_index0, sw_if_index0, drop0, r0;
 151           vnet_hw_interface_t *hw_if0;
 152           vlib_buffer_t *p0, *b0;
 153           ip_adjacency_t *adj0;
 154           ip6_address_t src;
 155           ip6_header_t *ip0;
 156
 157           pi0 = from[0];
 158
 159           p0 = vlib_get_buffer (vm, pi0);
 160
 161           adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
 162
 163           ip0 = vlib_buffer_get_current (p0);
 164
 165           adj0 = adj_get (adj_index0);
 166
 167           if (!is_glean)
 168             {
 169               ip0->dst_address.as_u64[0] =
 170                 adj0->sub_type.nbr.next_hop.ip6.as_u64[0];
 171               ip0->dst_address.as_u64[1] =
 172                 adj0->sub_type.nbr.next_hop.ip6.as_u64[1];
 173             }
 174
 175           sw_if_index0 = adj0->rewrite_header.sw_if_index;
 176           vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
 177
 178           /* combine the address and interface for a hash */
 179           r0 = ip6_address_hash_to_u64 (&ip0->dst_address) ^ sw_if_index0;
 180
 181           drop0 = throttle_check (&nd_throttle, thread_index, r0, seed);
 182
 183           from += 1;
 184           n_left_from -= 1;
 185           to_next_drop[0] = pi0;
 186           to_next_drop += 1;
 187           n_left_to_next_drop -= 1;
 188
 189           hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
 190
 191           /* If the interface is link-down, drop the pkt */
 192           if (!(hw_if0->flags & VNET_HW_INTERFACE_FLAG_LINK_UP))
 193             drop0 = 1;
 194
 195           if (!ip6_link_is_enabled (sw_if_index0))
 196             drop0 = 1;
 197
 198           /*
 199            * the adj has been updated to a rewrite but the node the DPO that got
 200            * us here hasn't - yet. no big deal. we'll drop while we wait.
 201            */
 202           if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
 203             drop0 = 1;
 204
 205           if (drop0)
 206             {
 207               p0->error = node->errors[IP6_NBR_ERROR_DROP];
 208               continue;
 209             }
 210
 211           /*
 212            * Choose source address based on destination lookup
 213            * adjacency.
 214            */
 215           if (!fib_sas6_get (sw_if_index0, &ip0->dst_address, &src))
 216             {
 217               /* There is no address on the interface */
 218               p0->error = node->errors[IP6_NBR_ERROR_NO_SOURCE_ADDRESS];
 219               continue;
 220             }
 221
 222           b0 = ip6_neighbor_probe (vm, vnm, sw_if_index0,
 223                                    &src, &ip0->dst_address);
 224
 225           if (PREDICT_TRUE (NULL != b0))
 226             {
 227               clib_memcpy_fast (b0->opaque2, p0->opaque2,
 228                                 sizeof (p0->opaque2));
 229               b0->flags |= p0->flags & VLIB_BUFFER_IS_TRACED;
 230               b0->trace_handle = p0->trace_handle;
 231               p0->error = node->errors[IP6_NBR_ERROR_REQUEST_SENT];
 232             }
 233           else
 234             {
 235               /* There is no address on the interface */
 236               p0->error = node->errors[IP6_NBR_ERROR_NO_BUFFERS];
 237               continue;
 238             }
 239         }
 240
 241       vlib_put_next_frame (vm, node, IP6_NBR_NEXT_DROP, n_left_to_next_drop);
 242     }
 243
 244   return frame->n_vectors;
 245 }
 246
 247 static uword
 248 ip6_discover_neighbor (vlib_main_t * vm,
 249                        vlib_node_runtime_t * node, vlib_frame_t * frame)
 250 {
 251   return (ip6_discover_neighbor_inline (vm, node, frame, 0));
 252 }
 253
 254 static uword
 255 ip6_glean (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 256 {
 257   return (ip6_discover_neighbor_inline (vm, node, frame, 1));
 258 }
 259
 260 static char *ip6_discover_neighbor_error_strings[] = {
 261   [IP6_NBR_ERROR_DROP] = "address overflow drops",
 262   [IP6_NBR_ERROR_REQUEST_SENT] = "neighbor solicitations sent",
 263   [IP6_NBR_ERROR_NO_SOURCE_ADDRESS] = "no source address for ND solicitation",
 264   [IP6_NBR_ERROR_NO_BUFFERS] = "no buffers",
 265 };
 266
 267 /* *INDENT-OFF* */
 268 VLIB_REGISTER_NODE (ip6_glean_node) =
 269 {
 270   .function = ip6_glean,
 271   .name = "ip6-glean",
 272   .vector_size = sizeof (u32),
 273   .format_trace = format_ip6_forward_next_trace,
 274   .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
 275   .error_strings = ip6_discover_neighbor_error_strings,
 276   .n_next_nodes = IP6_NBR_N_NEXT,
 277   .next_nodes =
 278   {
 279     [IP6_NBR_NEXT_DROP] = "ip6-drop",
 280     [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
 281   },
 282 };
 283 VLIB_REGISTER_NODE (ip6_discover_neighbor_node) =
 284 {
 285   .function = ip6_discover_neighbor,
 286   .name = "ip6-discover-neighbor",
 287   .vector_size = sizeof (u32),
 288   .format_trace = format_ip6_forward_next_trace,
 289   .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
 290   .error_strings = ip6_discover_neighbor_error_strings,
 291   .n_next_nodes = IP6_NBR_N_NEXT,
 292   .next_nodes =
 293   {
 294     [IP6_NBR_NEXT_DROP] = "ip6-drop",
 295     [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
 296   },
 297 };
 298 /* *INDENT-ON* */
 299
 300 /* Template used to generate IP6 neighbor solicitation packets. */
 301 vlib_packet_template_t ip6_neighbor_packet_template;
 302
 303 static clib_error_t *
 304 ip6_neighbor_init (vlib_main_t * vm)
 305 {
 306   icmp6_neighbor_solicitation_header_t p;
 307
 308   clib_memset (&p, 0, sizeof (p));
 309
 310   p.ip.ip_version_traffic_class_and_flow_label =
 311     clib_host_to_net_u32 (0x6 << 28);
 312   p.ip.payload_length =
 313     clib_host_to_net_u16 (sizeof (p) -
 314                           STRUCT_OFFSET_OF
 315                           (icmp6_neighbor_solicitation_header_t, neighbor));
 316   p.ip.protocol = IP_PROTOCOL_ICMP6;
 317   p.ip.hop_limit = 255;
 318   ip6_set_solicited_node_multicast_address (&p.ip.dst_address, 0);
 319
 320   p.neighbor.icmp.type = ICMP6_neighbor_solicitation;
 321
 322   p.link_layer_option.header.type =
 323     ICMP6_NEIGHBOR_DISCOVERY_OPTION_source_link_layer_address;
 324   p.link_layer_option.header.n_data_u64s =
 325     sizeof (p.link_layer_option) / sizeof (u64);
 326
 327   vlib_packet_template_init (vm,
 328                              &ip6_neighbor_packet_template, &p, sizeof (p),
 329                              /* alloc chunk size */ 8,
 330                              "ip6 neighbor discovery");
 331
 332   return NULL;
 333 }
 334
 335 VLIB_INIT_FUNCTION (ip6_neighbor_init);
 336
 337 static clib_error_t *
 338 ip6_nd_main_loop_enter (vlib_main_t * vm)
 339 {
 340   vlib_thread_main_t *tm = &vlib_thread_main;
 341
 342   throttle_init (&nd_throttle, tm->n_vlib_mains, 1e-3);
 343
 344   return 0;
 345 }
 346
 347 VLIB_MAIN_LOOP_ENTER_FUNCTION (ip6_nd_main_loop_enter);
 348
 349 /*
 350  * fd.io coding-style-patch-verification: ON
 351  *
 352  * Local Variables:
 353  * eval: (c-set-style "gnu")
 354  * End:
 355  */