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
  21 /** ND throttling */
  22 static throttle_t nd_throttle;
  23
  24 void
  25 ip6_neighbor_probe_dst (const ip_adjacency_t * adj, const ip6_address_t * dst)
  26 {
  27   ip_interface_address_t *ia;
  28   ip6_address_t *src;
  29
  30   src = ip6_interface_address_matching_destination
  31     (&ip6_main, dst, adj->rewrite_header.sw_if_index, &ia);
  32
  33   if (!src)
  34     return;
  35
  36   ip6_neighbor_probe (vlib_get_main (), vnet_get_main (), adj, src, dst);
  37 }
  38
  39 void
  40 ip6_neighbor_advertise (vlib_main_t * vm,
  41                         vnet_main_t * vnm,
  42                         u32 sw_if_index, const ip6_address_t * addr)
  43 {
  44   vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
  45   ip6_main_t *i6m = &ip6_main;
  46   u8 *rewrite, rewrite_len;
  47   u8 dst_address[6];
  48
  49   if (NULL == addr)
  50     addr = ip6_interface_first_address (i6m, sw_if_index);
  51
  52   if (addr)
  53     {
  54       clib_warning
  55         ("Sending unsolicitated NA IP6 address %U on sw_if_idex %d",
  56          format_ip6_address, addr, sw_if_index);
  57
  58       /* Form unsolicited neighbor advertisement packet from NS pkt template */
  59       int bogus_length;
  60       u32 bi = 0;
  61       icmp6_neighbor_solicitation_header_t *h =
  62         vlib_packet_template_get_packet (vm,
  63                                          &ip6_neighbor_packet_template,
  64                                          &bi);
  65       if (!h)
  66         return;
  67
  68       ip6_set_reserved_multicast_address (&h->ip.dst_address,
  69                                           IP6_MULTICAST_SCOPE_link_local,
  70                                           IP6_MULTICAST_GROUP_ID_all_hosts);
  71       h->ip.src_address = addr[0];
  72       h->neighbor.icmp.type = ICMP6_neighbor_advertisement;
  73       h->neighbor.target_address = addr[0];
  74       h->neighbor.advertisement_flags = clib_host_to_net_u32
  75         (ICMP6_NEIGHBOR_ADVERTISEMENT_FLAG_OVERRIDE);
  76       h->link_layer_option.header.type =
  77         ICMP6_NEIGHBOR_DISCOVERY_OPTION_target_link_layer_address;
  78       clib_memcpy (h->link_layer_option.ethernet_address,
  79                    hi->hw_address, vec_len (hi->hw_address));
  80       h->neighbor.icmp.checksum =
  81         ip6_tcp_udp_icmp_compute_checksum (vm, 0, &h->ip, &bogus_length);
  82       ASSERT (bogus_length == 0);
  83
  84       /* Setup MAC header with IP6 Etype and mcast DMAC */
  85       vlib_buffer_t *b = vlib_get_buffer (vm, bi);
  86       ip6_multicast_ethernet_address (dst_address,
  87                                       IP6_MULTICAST_GROUP_ID_all_hosts);
  88       rewrite =
  89         ethernet_build_rewrite (vnm, sw_if_index, VNET_LINK_IP6, dst_address);
  90       rewrite_len = vec_len (rewrite);
  91       vlib_buffer_advance (b, -rewrite_len);
  92       ethernet_header_t *e = vlib_buffer_get_current (b);
  93       clib_memcpy (e->dst_address, rewrite, rewrite_len);
  94       vec_free (rewrite);
  95
  96       /* Send unsolicited ND advertisement packet out the specified interface */
  97       vnet_buffer (b)->sw_if_index[VLIB_RX] =
  98         vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;
  99       vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
 100       u32 *to_next = vlib_frame_vector_args (f);
 101       to_next[0] = bi;
 102       f->n_vectors = 1;
 103       vlib_put_frame_to_node (vm, hi->output_node_index, f);
 104     }
 105 }
 106
 107 typedef enum
 108 {
 109   IP6_NBR_NEXT_DROP,
 110   IP6_NBR_NEXT_REPLY_TX,
 111   IP6_NBR_N_NEXT,
 112 } ip6_discover_neighbor_next_t;
 113
 114 typedef enum
 115 {
 116   IP6_NBR_ERROR_DROP,
 117   IP6_NBR_ERROR_REQUEST_SENT,
 118   IP6_NBR_ERROR_NO_SOURCE_ADDRESS,
 119   IP6_NBR_ERROR_NO_BUFFERS,
 120 } ip6_discover_neighbor_error_t;
 121
 122 static uword
 123 ip6_discover_neighbor_inline (vlib_main_t * vm,
 124                               vlib_node_runtime_t * node,
 125                               vlib_frame_t * frame, int is_glean)
 126 {
 127   vnet_main_t *vnm = vnet_get_main ();
 128   u32 *from, *to_next_drop;
 129   uword n_left_from, n_left_to_next_drop;
 130   u64 seed;
 131   u32 thread_index = vm->thread_index;
 132
 133   if (node->flags & VLIB_NODE_FLAG_TRACE)
 134     ip6_forward_next_trace (vm, node, frame, VLIB_TX);
 135
 136   seed = throttle_seed (&nd_throttle, thread_index, vlib_time_now (vm));
 137
 138   from = vlib_frame_vector_args (frame);
 139   n_left_from = frame->n_vectors;
 140
 141   while (n_left_from > 0)
 142     {
 143       vlib_get_next_frame (vm, node, IP6_NBR_NEXT_DROP,
 144                            to_next_drop, n_left_to_next_drop);
 145
 146       while (n_left_from > 0 && n_left_to_next_drop > 0)
 147         {
 148           u32 pi0, adj_index0, sw_if_index0, drop0, r0;
 149           vnet_hw_interface_t *hw_if0;
 150           vlib_buffer_t *p0, *b0;
 151           ip_adjacency_t *adj0;
 152           ip6_address_t src;
 153           ip6_header_t *ip0;
 154
 155           pi0 = from[0];
 156
 157           p0 = vlib_get_buffer (vm, pi0);
 158
 159           adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
 160
 161           ip0 = vlib_buffer_get_current (p0);
 162
 163           adj0 = adj_get (adj_index0);
 164
 165           if (!is_glean)
 166             {
 167               ip0->dst_address.as_u64[0] =
 168                 adj0->sub_type.nbr.next_hop.ip6.as_u64[0];
 169               ip0->dst_address.as_u64[1] =
 170                 adj0->sub_type.nbr.next_hop.ip6.as_u64[1];
 171             }
 172
 173           sw_if_index0 = adj0->rewrite_header.sw_if_index;
 174           vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
 175
 176           /* combine the address and interface for a hash */
 177           r0 = ip6_address_hash_to_u64 (&ip0->dst_address) ^ sw_if_index0;
 178
 179           drop0 = throttle_check (&nd_throttle, thread_index, r0, seed);
 180
 181           from += 1;
 182           n_left_from -= 1;
 183           to_next_drop[0] = pi0;
 184           to_next_drop += 1;
 185           n_left_to_next_drop -= 1;
 186
 187           hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
 188
 189           /* If the interface is link-down, drop the pkt */
 190           if (!(hw_if0->flags & VNET_HW_INTERFACE_FLAG_LINK_UP))
 191             drop0 = 1;
 192
 193           if (!ip6_link_is_enabled (sw_if_index0))
 194             drop0 = 1;
 195
 196           /*
 197            * the adj has been updated to a rewrite but the node the DPO that got
 198            * us here hasn't - yet. no big deal. we'll drop while we wait.
 199            */
 200           if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
 201             drop0 = 1;
 202
 203           if (drop0)
 204             {
 205               p0->error = node->errors[IP6_NBR_ERROR_DROP];
 206               continue;
 207             }
 208
 209           /*
 210            * Choose source address based on destination lookup
 211            * adjacency.
 212            */
 213           if (!ip6_src_address_for_packet (sw_if_index0,
 214                                            &ip0->dst_address, &src))
 215             {
 216               /* There is no address on the interface */
 217               p0->error = node->errors[IP6_NBR_ERROR_NO_SOURCE_ADDRESS];
 218               continue;
 219             }
 220
 221           b0 = ip6_neighbor_probe (vm, vnm, adj0, &src, &ip0->dst_address);
 222
 223           if (PREDICT_TRUE (NULL != b0))
 224             {
 225               clib_memcpy_fast (b0->opaque2, p0->opaque2,
 226                                 sizeof (p0->opaque2));
 227               b0->flags |= p0->flags & VLIB_BUFFER_IS_TRACED;
 228               b0->trace_handle = p0->trace_handle;
 229               p0->error = node->errors[IP6_NBR_ERROR_REQUEST_SENT];
 230             }
 231           else
 232             {
 233               /* There is no address on the interface */
 234               p0->error = node->errors[IP6_NBR_ERROR_NO_BUFFERS];
 235               continue;
 236             }
 237         }
 238
 239       vlib_put_next_frame (vm, node, IP6_NBR_NEXT_DROP, n_left_to_next_drop);
 240     }
 241
 242   return frame->n_vectors;
 243 }
 244
 245 static uword
 246 ip6_discover_neighbor (vlib_main_t * vm,
 247                        vlib_node_runtime_t * node, vlib_frame_t * frame)
 248 {
 249   return (ip6_discover_neighbor_inline (vm, node, frame, 0));
 250 }
 251
 252 static uword
 253 ip6_glean (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
 254 {
 255   return (ip6_discover_neighbor_inline (vm, node, frame, 1));
 256 }
 257
 258 static char *ip6_discover_neighbor_error_strings[] = {
 259   [IP6_NBR_ERROR_DROP] = "address overflow drops",
 260   [IP6_NBR_ERROR_REQUEST_SENT] = "neighbor solicitations sent",
 261   [IP6_NBR_ERROR_NO_SOURCE_ADDRESS] = "no source address for ND solicitation",
 262   [IP6_NBR_ERROR_NO_BUFFERS] = "no buffers",
 263 };
 264
 265 /* *INDENT-OFF* */
 266 VLIB_REGISTER_NODE (ip6_glean_node) =
 267 {
 268   .function = ip6_glean,
 269   .name = "ip6-glean",
 270   .vector_size = sizeof (u32),
 271   .format_trace = format_ip6_forward_next_trace,
 272   .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
 273   .error_strings = ip6_discover_neighbor_error_strings,
 274   .n_next_nodes = IP6_NBR_N_NEXT,
 275   .next_nodes =
 276   {
 277     [IP6_NBR_NEXT_DROP] = "ip6-drop",
 278     [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
 279   },
 280 };
 281 VLIB_REGISTER_NODE (ip6_discover_neighbor_node) =
 282 {
 283   .function = ip6_discover_neighbor,
 284   .name = "ip6-discover-neighbor",
 285   .vector_size = sizeof (u32),
 286   .format_trace = format_ip6_forward_next_trace,
 287   .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
 288   .error_strings = ip6_discover_neighbor_error_strings,
 289   .n_next_nodes = IP6_NBR_N_NEXT,
 290   .next_nodes =
 291   {
 292     [IP6_NBR_NEXT_DROP] = "ip6-drop",
 293     [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
 294   },
 295 };
 296 /* *INDENT-ON* */
 297
 298 /* Template used to generate IP6 neighbor solicitation packets. */
 299 vlib_packet_template_t ip6_neighbor_packet_template;
 300
 301 static clib_error_t *
 302 ip6_neighbor_init (vlib_main_t * vm)
 303 {
 304   icmp6_neighbor_solicitation_header_t p;
 305
 306   clib_memset (&p, 0, sizeof (p));
 307
 308   p.ip.ip_version_traffic_class_and_flow_label =
 309     clib_host_to_net_u32 (0x6 << 28);
 310   p.ip.payload_length =
 311     clib_host_to_net_u16 (sizeof (p) -
 312                           STRUCT_OFFSET_OF
 313                           (icmp6_neighbor_solicitation_header_t, neighbor));
 314   p.ip.protocol = IP_PROTOCOL_ICMP6;
 315   p.ip.hop_limit = 255;
 316   ip6_set_solicited_node_multicast_address (&p.ip.dst_address, 0);
 317
 318   p.neighbor.icmp.type = ICMP6_neighbor_solicitation;
 319
 320   p.link_layer_option.header.type =
 321     ICMP6_NEIGHBOR_DISCOVERY_OPTION_source_link_layer_address;
 322   p.link_layer_option.header.n_data_u64s =
 323     sizeof (p.link_layer_option) / sizeof (u64);
 324
 325   vlib_packet_template_init (vm,
 326                              &ip6_neighbor_packet_template, &p, sizeof (p),
 327                              /* alloc chunk size */ 8,
 328                              "ip6 neighbor discovery");
 329
 330   return NULL;
 331 }
 332
 333 VLIB_INIT_FUNCTION (ip6_neighbor_init);
 334
 335 static clib_error_t *
 336 ip6_nd_main_loop_enter (vlib_main_t * vm)
 337 {
 338   vlib_thread_main_t *tm = &vlib_thread_main;
 339
 340   throttle_init (&nd_throttle, tm->n_vlib_mains, 1e-3);
 341
 342   return 0;
 343 }
 344
 345 VLIB_MAIN_LOOP_ENTER_FUNCTION (ip6_nd_main_loop_enter);
 346
 347 /*
 348  * fd.io coding-style-patch-verification: ON
 349  *
 350  * Local Variables:
 351  * eval: (c-set-style "gnu")
 352  * End:
 353  */