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