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 #include <vnet/ip/ip_sas.h>
  22
  23 /** ND throttling */
  24 static throttle_t nd_throttle;
  25
  26 VLIB_REGISTER_LOG_CLASS (ip6_neighbor_log, static) = {
  27   .class_name = "ip6",
  28   .subclass_name = "neighbor",
  29 };
  30
  31 #define log_debug(fmt, ...)                                                   \
  32   vlib_log_debug (ip6_neighbor_log.class, fmt, __VA_ARGS__)
  33 void
  34 ip6_neighbor_probe_dst (u32 sw_if_index, u32 thread_index,
  35                         const ip6_address_t *dst)
  36 {
  37   ip6_address_t src;
  38
  39   if (fib_sas6_get (sw_if_index, dst, &src) ||
  40       ip6_sas_by_sw_if_index (sw_if_index, dst, &src))
  41     ip6_neighbor_probe (vlib_get_main (), vnet_get_main (), sw_if_index,
  42                         thread_index, &src, dst);
  43 }
  44
  45 void
  46 ip6_neighbor_advertise (vlib_main_t *vm, vnet_main_t *vnm, u32 sw_if_index,
  47                         u32 thread_index, const ip6_address_t *addr)
  48 {
  49   vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
  50   ip6_main_t *i6m = &ip6_main;
  51   u8 *rewrite, rewrite_len;
  52   u8 dst_address[6];
  53
  54   if (NULL == addr)
  55     addr = ip6_interface_first_address (i6m, sw_if_index);
  56
  57   if (addr)
  58     {
  59       log_debug ("Sending unsolicitated NA IP6 address %U on sw_if_idex %d",
  60                  format_ip6_address, addr, sw_if_index);
  61
  62       /* Form unsolicited neighbor advertisement packet from NS pkt template */
  63       int bogus_length;
  64       u32 bi = 0;
  65       icmp6_neighbor_solicitation_header_t *h =
  66         vlib_packet_template_get_packet (vm,
  67                                          &ip6_neighbor_packet_template,
  68                                          &bi);
  69       if (!h)
  70         return;
  71
  72       ip6_set_reserved_multicast_address (&h->ip.dst_address,
  73                                           IP6_MULTICAST_SCOPE_link_local,
  74                                           IP6_MULTICAST_GROUP_ID_all_hosts);
  75       h->ip.src_address = addr[0];
  76       h->neighbor.icmp.type = ICMP6_neighbor_advertisement;
  77       h->neighbor.target_address = addr[0];
  78       h->neighbor.advertisement_flags = clib_host_to_net_u32
  79         (ICMP6_NEIGHBOR_ADVERTISEMENT_FLAG_OVERRIDE);
  80       h->link_layer_option.header.type =
  81         ICMP6_NEIGHBOR_DISCOVERY_OPTION_target_link_layer_address;
  82       clib_memcpy (h->link_layer_option.ethernet_address,
  83                    hi->hw_address, vec_len (hi->hw_address));
  84       h->neighbor.icmp.checksum =
  85         ip6_tcp_udp_icmp_compute_checksum (vm, 0, &h->ip, &bogus_length);
  86       ASSERT (bogus_length == 0);
  87
  88       /* Setup MAC header with IP6 Etype and mcast DMAC */
  89       vlib_buffer_t *b = vlib_get_buffer (vm, bi);
  90       ip6_multicast_ethernet_address (dst_address,
  91                                       IP6_MULTICAST_GROUP_ID_all_hosts);
  92       rewrite =
  93         ethernet_build_rewrite (vnm, sw_if_index, VNET_LINK_IP6, dst_address);
  94       rewrite_len = vec_len (rewrite);
  95       vlib_buffer_advance (b, -rewrite_len);
  96       ethernet_header_t *e = vlib_buffer_get_current (b);
  97       clib_memcpy (e->dst_address, rewrite, rewrite_len);
  98       vec_free (rewrite);
  99
 100       /* Send unsolicited ND advertisement packet out the specified interface */
 101       vnet_buffer (b)->sw_if_index[VLIB_RX] =
 102         vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;
 103       vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
 104       u32 *to_next = vlib_frame_vector_args (f);
 105       to_next[0] = bi;
 106       f->n_vectors = 1;
 107       vlib_put_frame_to_node (vm, hi->output_node_index, f);
 108
 109       vlib_increment_simple_counter (
 110         &ip_neighbor_counters[AF_IP6].ipnc[VLIB_TX][IP_NEIGHBOR_CTR_GRAT],
 111         thread_index, sw_if_index, 1);
 112     }
 113 }
 114
 115 typedef enum
 116 {
 117   IP6_NBR_NEXT_DROP,
 118   IP6_NBR_NEXT_REPLY_TX,
 119   IP6_NBR_N_NEXT,
 120 } ip6_discover_neighbor_next_t;
 121
 122 typedef enum
 123 {
 124   IP6_NBR_ERROR_DROP,
 125   IP6_NBR_ERROR_REQUEST_SENT,
 126   IP6_NBR_ERROR_NO_SOURCE_ADDRESS,
 127   IP6_NBR_ERROR_NO_BUFFERS,
 128 } ip6_discover_neighbor_error_t;
 129
 130 static uword
 131 ip6_discover_neighbor_inline (vlib_main_t * vm,
 132                               vlib_node_runtime_t * node,
 133                               vlib_frame_t * frame, int is_glean)
 134 {
 135   vnet_main_t *vnm = vnet_get_main ();
 136   u32 *from, *to_next_drop;
 137   uword n_left_from, n_left_to_next_drop;
 138   u64 seed;
 139   u32 thread_index = vm->thread_index;
 140
 141   if (node->flags & VLIB_NODE_FLAG_TRACE)
 142     ip6_forward_next_trace (vm, node, frame, VLIB_TX);
 143
 144   seed = throttle_seed (&nd_throttle, thread_index, vlib_time_now (vm));
 145
 146   from = vlib_frame_vector_args (frame);
 147   n_left_from = frame->n_vectors;
 148
 149   while (n_left_from > 0)
 150     {
 151       vlib_get_next_frame (vm, node, IP6_NBR_NEXT_DROP,
 152                            to_next_drop, n_left_to_next_drop);
 153
 154       while (n_left_from > 0 && n_left_to_next_drop > 0)
 155         {
 156           u32 pi0, adj_index0, sw_if_index0, drop0, r0;
 157           vnet_hw_interface_t *hw_if0;
 158           vlib_buffer_t *p0, *b0;
 159           ip_adjacency_t *adj0;
 160           ip6_address_t src;
 161           ip6_header_t *ip0;
 162
 163           pi0 = from[0];
 164
 165           p0 = vlib_get_buffer (vm, pi0);
 166
 167           adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
 168
 169           ip0 = vlib_buffer_get_current (p0);
 170
 171           adj0 = adj_get (adj_index0);
 172
 173           if (!is_glean)
 174             {
 175               ip0->dst_address.as_u64[0] =
 176                 adj0->sub_type.nbr.next_hop.ip6.as_u64[0];
 177               ip0->dst_address.as_u64[1] =
 178                 adj0->sub_type.nbr.next_hop.ip6.as_u64[1];
 179             }
 180
 181           sw_if_index0 = adj0->rewrite_header.sw_if_index;
 182           vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
 183
 184           /* combine the address and interface for a hash */
 185           r0 = ip6_address_hash_to_u64 (&ip0->dst_address) ^ sw_if_index0;
 186
 187           drop0 = throttle_check (&nd_throttle, thread_index, r0, seed);
 188
 189           from += 1;
 190           n_left_from -= 1;
 191           to_next_drop[0] = pi0;
 192           to_next_drop += 1;
 193           n_left_to_next_drop -= 1;
 194
 195           hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
 196
 197           /* If the interface is link-down, drop the pkt */
 198           if (!(hw_if0->flags & VNET_HW_INTERFACE_FLAG_LINK_UP))
 199             drop0 = 1;
 200
 201           if (!ip6_link_is_enabled (sw_if_index0))
 202             drop0 = 1;
 203
 204           /*
 205            * the adj has been updated to a rewrite but the node the DPO that got
 206            * us here hasn't - yet. no big deal. we'll drop while we wait.
 207            */
 208           if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
 209             drop0 = 1;
 210
 211           if (drop0)
 212             {
 213               p0->error = node->errors[IP6_NBR_ERROR_DROP];
 214               continue;
 215             }
 216
 217           /*
 218            * Choose source address based on destination lookup
 219            * adjacency.
 220            */
 221           if (!fib_sas6_get (sw_if_index0, &ip0->dst_address, &src) ||
 222               !ip6_sas_by_sw_if_index (sw_if_index0, &ip0->dst_address, &src))
 223             {
 224               /* There is no address on the interface */
 225               p0->error = node->errors[IP6_NBR_ERROR_NO_SOURCE_ADDRESS];
 226               continue;
 227             }
 228
 229           b0 = ip6_neighbor_probe (vm, vnm, sw_if_index0, thread_index, &src,
 230                                    &ip0->dst_address);
 231
 232           if (PREDICT_TRUE (NULL != b0))
 233             {
 234               clib_memcpy_fast (b0->opaque2, p0->opaque2,
 235                                 sizeof (p0->opaque2));
 236               b0->flags |= p0->flags & VLIB_BUFFER_IS_TRACED;
 237               b0->trace_handle = p0->trace_handle;
 238               p0->error = node->errors[IP6_NBR_ERROR_REQUEST_SENT];
 239             }
 240           else
 241             {
 242               /* There is no address on the interface */
 243               p0->error = node->errors[IP6_NBR_ERROR_NO_BUFFERS];
 244               continue;
 245             }
 246         }
 247
 248       vlib_put_next_frame (vm, node, IP6_NBR_NEXT_DROP, n_left_to_next_drop);
 249     }
 250
 251   return frame->n_vectors;
 252 }
 253
 254 static uword
 255 ip6_discover_neighbor (vlib_main_t * vm,
 256                        vlib_node_runtime_t * node, vlib_frame_t * frame)
 257 {
 258   return (ip6_discover_neighbor_inline (vm, node, frame, 0));
 259 }
 260
 261 static uword
 262 ip6_glean (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 263 {
 264   return (ip6_discover_neighbor_inline (vm, node, frame, 1));
 265 }
 266
 267 static char *ip6_discover_neighbor_error_strings[] = {
 268   [IP6_NBR_ERROR_DROP] = "address overflow drops",
 269   [IP6_NBR_ERROR_REQUEST_SENT] = "neighbor solicitations sent",
 270   [IP6_NBR_ERROR_NO_SOURCE_ADDRESS] = "no source address for ND solicitation",
 271   [IP6_NBR_ERROR_NO_BUFFERS] = "no buffers",
 272 };
 273
 274 /* *INDENT-OFF* */
 275 VLIB_REGISTER_NODE (ip6_glean_node) =
 276 {
 277   .function = ip6_glean,
 278   .name = "ip6-glean",
 279   .vector_size = sizeof (u32),
 280   .format_trace = format_ip6_forward_next_trace,
 281   .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
 282   .error_strings = ip6_discover_neighbor_error_strings,
 283   .n_next_nodes = IP6_NBR_N_NEXT,
 284   .next_nodes =
 285   {
 286     [IP6_NBR_NEXT_DROP] = "ip6-drop",
 287     [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
 288   },
 289 };
 290 VLIB_REGISTER_NODE (ip6_discover_neighbor_node) =
 291 {
 292   .function = ip6_discover_neighbor,
 293   .name = "ip6-discover-neighbor",
 294   .vector_size = sizeof (u32),
 295   .format_trace = format_ip6_forward_next_trace,
 296   .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
 297   .error_strings = ip6_discover_neighbor_error_strings,
 298   .n_next_nodes = IP6_NBR_N_NEXT,
 299   .next_nodes =
 300   {
 301     [IP6_NBR_NEXT_DROP] = "ip6-drop",
 302     [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
 303   },
 304 };
 305 /* *INDENT-ON* */
 306
 307 /* Template used to generate IP6 neighbor solicitation packets. */
 308 vlib_packet_template_t ip6_neighbor_packet_template;
 309
 310 static clib_error_t *
 311 ip6_neighbor_init (vlib_main_t * vm)
 312 {
 313   icmp6_neighbor_solicitation_header_t p;
 314
 315   clib_memset (&p, 0, sizeof (p));
 316
 317   p.ip.ip_version_traffic_class_and_flow_label =
 318     clib_host_to_net_u32 (0x6 << 28);
 319   p.ip.payload_length =
 320     clib_host_to_net_u16 (sizeof (p) -
 321                           STRUCT_OFFSET_OF
 322                           (icmp6_neighbor_solicitation_header_t, neighbor));
 323   p.ip.protocol = IP_PROTOCOL_ICMP6;
 324   p.ip.hop_limit = 255;
 325   ip6_set_solicited_node_multicast_address (&p.ip.dst_address, 0);
 326
 327   p.neighbor.icmp.type = ICMP6_neighbor_solicitation;
 328
 329   p.link_layer_option.header.type =
 330     ICMP6_NEIGHBOR_DISCOVERY_OPTION_source_link_layer_address;
 331   p.link_layer_option.header.n_data_u64s =
 332     sizeof (p.link_layer_option) / sizeof (u64);
 333
 334   vlib_packet_template_init (vm,
 335                              &ip6_neighbor_packet_template, &p, sizeof (p),
 336                              /* alloc chunk size */ 8,
 337                              "ip6 neighbor discovery");
 338
 339   return NULL;
 340 }
 341
 342 VLIB_INIT_FUNCTION (ip6_neighbor_init);
 343
 344 static clib_error_t *
 345 ip6_nd_main_loop_enter (vlib_main_t * vm)
 346 {
 347   vlib_thread_main_t *tm = &vlib_thread_main;
 348
 349   throttle_init (&nd_throttle, tm->n_vlib_mains, 1e-3);
 350
 351   return 0;
 352 }
 353
 354 VLIB_MAIN_LOOP_ENTER_FUNCTION (ip6_nd_main_loop_enter);
 355
 356 /*
 357  * fd.io coding-style-patch-verification: ON
 358  *
 359  * Local Variables:
 360  * eval: (c-set-style "gnu")
 361  * End:
 362  */