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, const ip6_address_t * dst)
  35 {
  36   ip6_address_t src;
  37
  38   if (fib_sas6_get (sw_if_index, dst, &src) ||
  39       ip6_sas_by_sw_if_index (sw_if_index, dst, &src))
  40     ip6_neighbor_probe (vlib_get_main (), vnet_get_main (),
  41                         sw_if_index, &src, dst);
  42 }
  43
  44 void
  45 ip6_neighbor_advertise (vlib_main_t * vm,
  46                         vnet_main_t * vnm,
  47                         u32 sw_if_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 }
 110
 111 typedef enum
 112 {
 113   IP6_NBR_NEXT_DROP,
 114   IP6_NBR_NEXT_REPLY_TX,
 115   IP6_NBR_N_NEXT,
 116 } ip6_discover_neighbor_next_t;
 117
 118 typedef enum
 119 {
 120   IP6_NBR_ERROR_DROP,
 121   IP6_NBR_ERROR_REQUEST_SENT,
 122   IP6_NBR_ERROR_NO_SOURCE_ADDRESS,
 123   IP6_NBR_ERROR_NO_BUFFERS,
 124 } ip6_discover_neighbor_error_t;
 125
 126 static uword
 127 ip6_discover_neighbor_inline (vlib_main_t * vm,
 128                               vlib_node_runtime_t * node,
 129                               vlib_frame_t * frame, int is_glean)
 130 {
 131   vnet_main_t *vnm = vnet_get_main ();
 132   u32 *from, *to_next_drop;
 133   uword n_left_from, n_left_to_next_drop;
 134   u64 seed;
 135   u32 thread_index = vm->thread_index;
 136
 137   if (node->flags & VLIB_NODE_FLAG_TRACE)
 138     ip6_forward_next_trace (vm, node, frame, VLIB_TX);
 139
 140   seed = throttle_seed (&nd_throttle, thread_index, vlib_time_now (vm));
 141
 142   from = vlib_frame_vector_args (frame);
 143   n_left_from = frame->n_vectors;
 144
 145   while (n_left_from > 0)
 146     {
 147       vlib_get_next_frame (vm, node, IP6_NBR_NEXT_DROP,
 148                            to_next_drop, n_left_to_next_drop);
 149
 150       while (n_left_from > 0 && n_left_to_next_drop > 0)
 151         {
 152           u32 pi0, adj_index0, sw_if_index0, drop0, r0;
 153           vnet_hw_interface_t *hw_if0;
 154           vlib_buffer_t *p0, *b0;
 155           ip_adjacency_t *adj0;
 156           ip6_address_t src;
 157           ip6_header_t *ip0;
 158
 159           pi0 = from[0];
 160
 161           p0 = vlib_get_buffer (vm, pi0);
 162
 163           adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
 164
 165           ip0 = vlib_buffer_get_current (p0);
 166
 167           adj0 = adj_get (adj_index0);
 168
 169           if (!is_glean)
 170             {
 171               ip0->dst_address.as_u64[0] =
 172                 adj0->sub_type.nbr.next_hop.ip6.as_u64[0];
 173               ip0->dst_address.as_u64[1] =
 174                 adj0->sub_type.nbr.next_hop.ip6.as_u64[1];
 175             }
 176
 177           sw_if_index0 = adj0->rewrite_header.sw_if_index;
 178           vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
 179
 180           /* combine the address and interface for a hash */
 181           r0 = ip6_address_hash_to_u64 (&ip0->dst_address) ^ sw_if_index0;
 182
 183           drop0 = throttle_check (&nd_throttle, thread_index, r0, seed);
 184
 185           from += 1;
 186           n_left_from -= 1;
 187           to_next_drop[0] = pi0;
 188           to_next_drop += 1;
 189           n_left_to_next_drop -= 1;
 190
 191           hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
 192
 193           /* If the interface is link-down, drop the pkt */
 194           if (!(hw_if0->flags & VNET_HW_INTERFACE_FLAG_LINK_UP))
 195             drop0 = 1;
 196
 197           if (!ip6_link_is_enabled (sw_if_index0))
 198             drop0 = 1;
 199
 200           /*
 201            * the adj has been updated to a rewrite but the node the DPO that got
 202            * us here hasn't - yet. no big deal. we'll drop while we wait.
 203            */
 204           if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
 205             drop0 = 1;
 206
 207           if (drop0)
 208             {
 209               p0->error = node->errors[IP6_NBR_ERROR_DROP];
 210               continue;
 211             }
 212
 213           /*
 214            * Choose source address based on destination lookup
 215            * adjacency.
 216            */
 217           if (!fib_sas6_get (sw_if_index0, &ip0->dst_address, &src) ||
 218               !ip6_sas_by_sw_if_index (sw_if_index0, &ip0->dst_address, &src))
 219             {
 220               /* There is no address on the interface */
 221               p0->error = node->errors[IP6_NBR_ERROR_NO_SOURCE_ADDRESS];
 222               continue;
 223             }
 224
 225           b0 = ip6_neighbor_probe (vm, vnm, sw_if_index0,
 226                                    &src, &ip0->dst_address);
 227
 228           if (PREDICT_TRUE (NULL != b0))
 229             {
 230               clib_memcpy_fast (b0->opaque2, p0->opaque2,
 231                                 sizeof (p0->opaque2));
 232               b0->flags |= p0->flags & VLIB_BUFFER_IS_TRACED;
 233               b0->trace_handle = p0->trace_handle;
 234               p0->error = node->errors[IP6_NBR_ERROR_REQUEST_SENT];
 235             }
 236           else
 237             {
 238               /* There is no address on the interface */
 239               p0->error = node->errors[IP6_NBR_ERROR_NO_BUFFERS];
 240               continue;
 241             }
 242         }
 243
 244       vlib_put_next_frame (vm, node, IP6_NBR_NEXT_DROP, n_left_to_next_drop);
 245     }
 246
 247   return frame->n_vectors;
 248 }
 249
 250 static uword
 251 ip6_discover_neighbor (vlib_main_t * vm,
 252                        vlib_node_runtime_t * node, vlib_frame_t * frame)
 253 {
 254   return (ip6_discover_neighbor_inline (vm, node, frame, 0));
 255 }
 256
 257 static uword
 258 ip6_glean (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 259 {
 260   return (ip6_discover_neighbor_inline (vm, node, frame, 1));
 261 }
 262
 263 static char *ip6_discover_neighbor_error_strings[] = {
 264   [IP6_NBR_ERROR_DROP] = "address overflow drops",
 265   [IP6_NBR_ERROR_REQUEST_SENT] = "neighbor solicitations sent",
 266   [IP6_NBR_ERROR_NO_SOURCE_ADDRESS] = "no source address for ND solicitation",
 267   [IP6_NBR_ERROR_NO_BUFFERS] = "no buffers",
 268 };
 269
 270 /* *INDENT-OFF* */
 271 VLIB_REGISTER_NODE (ip6_glean_node) =
 272 {
 273   .function = ip6_glean,
 274   .name = "ip6-glean",
 275   .vector_size = sizeof (u32),
 276   .format_trace = format_ip6_forward_next_trace,
 277   .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
 278   .error_strings = ip6_discover_neighbor_error_strings,
 279   .n_next_nodes = IP6_NBR_N_NEXT,
 280   .next_nodes =
 281   {
 282     [IP6_NBR_NEXT_DROP] = "ip6-drop",
 283     [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
 284   },
 285 };
 286 VLIB_REGISTER_NODE (ip6_discover_neighbor_node) =
 287 {
 288   .function = ip6_discover_neighbor,
 289   .name = "ip6-discover-neighbor",
 290   .vector_size = sizeof (u32),
 291   .format_trace = format_ip6_forward_next_trace,
 292   .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
 293   .error_strings = ip6_discover_neighbor_error_strings,
 294   .n_next_nodes = IP6_NBR_N_NEXT,
 295   .next_nodes =
 296   {
 297     [IP6_NBR_NEXT_DROP] = "ip6-drop",
 298     [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
 299   },
 300 };
 301 /* *INDENT-ON* */
 302
 303 /* Template used to generate IP6 neighbor solicitation packets. */
 304 vlib_packet_template_t ip6_neighbor_packet_template;
 305
 306 static clib_error_t *
 307 ip6_neighbor_init (vlib_main_t * vm)
 308 {
 309   icmp6_neighbor_solicitation_header_t p;
 310
 311   clib_memset (&p, 0, sizeof (p));
 312
 313   p.ip.ip_version_traffic_class_and_flow_label =
 314     clib_host_to_net_u32 (0x6 << 28);
 315   p.ip.payload_length =
 316     clib_host_to_net_u16 (sizeof (p) -
 317                           STRUCT_OFFSET_OF
 318                           (icmp6_neighbor_solicitation_header_t, neighbor));
 319   p.ip.protocol = IP_PROTOCOL_ICMP6;
 320   p.ip.hop_limit = 255;
 321   ip6_set_solicited_node_multicast_address (&p.ip.dst_address, 0);
 322
 323   p.neighbor.icmp.type = ICMP6_neighbor_solicitation;
 324
 325   p.link_layer_option.header.type =
 326     ICMP6_NEIGHBOR_DISCOVERY_OPTION_source_link_layer_address;
 327   p.link_layer_option.header.n_data_u64s =
 328     sizeof (p.link_layer_option) / sizeof (u64);
 329
 330   vlib_packet_template_init (vm,
 331                              &ip6_neighbor_packet_template, &p, sizeof (p),
 332                              /* alloc chunk size */ 8,
 333                              "ip6 neighbor discovery");
 334
 335   return NULL;
 336 }
 337
 338 VLIB_INIT_FUNCTION (ip6_neighbor_init);
 339
 340 static clib_error_t *
 341 ip6_nd_main_loop_enter (vlib_main_t * vm)
 342 {
 343   vlib_thread_main_t *tm = &vlib_thread_main;
 344
 345   throttle_init (&nd_throttle, tm->n_vlib_mains, 1e-3);
 346
 347   return 0;
 348 }
 349
 350 VLIB_MAIN_LOOP_ENTER_FUNCTION (ip6_nd_main_loop_enter);
 351
 352 /*
 353  * fd.io coding-style-patch-verification: ON
 354  *
 355  * Local Variables:
 356  * eval: (c-set-style "gnu")
 357  * End:
 358  */