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/ip-neighbor/ip_neighbor.api_enum.h>
  20 #include <vnet/util/throttle.h>
  21 #include <vnet/fib/fib_sas.h>
  22 #include <vnet/ip/ip_sas.h>
  23
  24 /** ND throttling */
  25 static throttle_t nd_throttle;
  26
  27 VLIB_REGISTER_LOG_CLASS (ip6_neighbor_log, static) = {
  28   .class_name = "ip6",
  29   .subclass_name = "neighbor",
  30 };
  31
  32 #define log_debug(fmt, ...)                                                   \
  33   vlib_log_debug (ip6_neighbor_log.class, fmt, __VA_ARGS__)
  34 void
  35 ip6_neighbor_probe_dst (u32 sw_if_index, u32 thread_index,
  36                         const ip6_address_t *dst)
  37 {
  38   ip6_address_t src;
  39
  40   if (fib_sas6_get (sw_if_index, dst, &src) ||
  41       ip6_sas_by_sw_if_index (sw_if_index, dst, &src))
  42     ip6_neighbor_probe (vlib_get_main (), vnet_get_main (), sw_if_index,
  43                         thread_index, &src, dst);
  44 }
  45
  46 void
  47 ip6_neighbor_advertise (vlib_main_t *vm, vnet_main_t *vnm, u32 sw_if_index,
  48                         u32 thread_index, const ip6_address_t *addr)
  49 {
  50   vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
  51   ip6_main_t *i6m = &ip6_main;
  52   u8 *rewrite, rewrite_len;
  53   u8 dst_address[6];
  54
  55   if (NULL == addr)
  56     addr = ip6_interface_first_address (i6m, sw_if_index);
  57
  58   if (addr)
  59     {
  60       log_debug ("Sending unsolicitated NA IP6 address %U on sw_if_idex %d",
  61                  format_ip6_address, addr, sw_if_index);
  62
  63       /* Form unsolicited neighbor advertisement packet from NS pkt template */
  64       int bogus_length;
  65       u32 bi = 0;
  66       icmp6_neighbor_solicitation_header_t *h =
  67         vlib_packet_template_get_packet (vm,
  68                                          &ip6_neighbor_packet_template,
  69                                          &bi);
  70       if (!h)
  71         return;
  72
  73       ip6_set_reserved_multicast_address (&h->ip.dst_address,
  74                                           IP6_MULTICAST_SCOPE_link_local,
  75                                           IP6_MULTICAST_GROUP_ID_all_hosts);
  76       h->ip.src_address = addr[0];
  77       h->neighbor.icmp.type = ICMP6_neighbor_advertisement;
  78       h->neighbor.target_address = addr[0];
  79       h->neighbor.advertisement_flags = clib_host_to_net_u32
  80         (ICMP6_NEIGHBOR_ADVERTISEMENT_FLAG_OVERRIDE);
  81       h->link_layer_option.header.type =
  82         ICMP6_NEIGHBOR_DISCOVERY_OPTION_target_link_layer_address;
  83       clib_memcpy (h->link_layer_option.ethernet_address,
  84                    hi->hw_address, vec_len (hi->hw_address));
  85       h->neighbor.icmp.checksum =
  86         ip6_tcp_udp_icmp_compute_checksum (vm, 0, &h->ip, &bogus_length);
  87       ASSERT (bogus_length == 0);
  88
  89       /* Setup MAC header with IP6 Etype and mcast DMAC */
  90       vlib_buffer_t *b = vlib_get_buffer (vm, bi);
  91       ip6_multicast_ethernet_address (dst_address,
  92                                       IP6_MULTICAST_GROUP_ID_all_hosts);
  93       rewrite =
  94         ethernet_build_rewrite (vnm, sw_if_index, VNET_LINK_IP6, dst_address);
  95       rewrite_len = vec_len (rewrite);
  96       vlib_buffer_advance (b, -rewrite_len);
  97       ethernet_header_t *e = vlib_buffer_get_current (b);
  98       clib_memcpy (e->dst_address, rewrite, rewrite_len);
  99       vec_free (rewrite);
 100
 101       /* Send unsolicited ND advertisement packet out the specified interface */
 102       vnet_buffer (b)->sw_if_index[VLIB_RX] =
 103         vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;
 104       vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
 105       u32 *to_next = vlib_frame_vector_args (f);
 106       to_next[0] = bi;
 107       f->n_vectors = 1;
 108       vlib_put_frame_to_node (vm, hi->output_node_index, f);
 109
 110       vlib_increment_simple_counter (
 111         &ip_neighbor_counters[AF_IP6].ipnc[VLIB_TX][IP_NEIGHBOR_CTR_GRAT],
 112         thread_index, sw_if_index, 1);
 113     }
 114 }
 115
 116 typedef enum
 117 {
 118   IP6_NBR_NEXT_DROP,
 119   IP6_NBR_NEXT_REPLY_TX,
 120   IP6_NBR_N_NEXT,
 121 } ip6_discover_neighbor_next_t;
 122
 123 static uword
 124 ip6_discover_neighbor_inline (vlib_main_t * vm,
 125                               vlib_node_runtime_t * node,
 126                               vlib_frame_t * frame, int is_glean)
 127 {
 128   vnet_main_t *vnm = vnet_get_main ();
 129   u32 *from, *to_next_drop;
 130   uword n_left_from, n_left_to_next_drop;
 131   u64 seed;
 132   u32 thread_index = vm->thread_index;
 133
 134   if (node->flags & VLIB_NODE_FLAG_TRACE)
 135     ip6_forward_next_trace (vm, node, frame, VLIB_TX);
 136
 137   seed = throttle_seed (&nd_throttle, thread_index, vlib_time_now (vm));
 138
 139   from = vlib_frame_vector_args (frame);
 140   n_left_from = frame->n_vectors;
 141
 142   while (n_left_from > 0)
 143     {
 144       vlib_get_next_frame (vm, node, IP6_NBR_NEXT_DROP,
 145                            to_next_drop, n_left_to_next_drop);
 146
 147       while (n_left_from > 0 && n_left_to_next_drop > 0)
 148         {
 149           u32 pi0, adj_index0, sw_if_index0, drop0, r0;
 150           vnet_hw_interface_t *hw_if0;
 151           vlib_buffer_t *p0, *b0;
 152           ip_adjacency_t *adj0;
 153           ip6_address_t src;
 154           ip6_header_t *ip0;
 155
 156           pi0 = from[0];
 157
 158           p0 = vlib_get_buffer (vm, pi0);
 159
 160           adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
 161
 162           ip0 = vlib_buffer_get_current (p0);
 163
 164           adj0 = adj_get (adj_index0);
 165
 166           if (!is_glean)
 167             {
 168               ip0->dst_address.as_u64[0] =
 169                 adj0->sub_type.nbr.next_hop.ip6.as_u64[0];
 170               ip0->dst_address.as_u64[1] =
 171                 adj0->sub_type.nbr.next_hop.ip6.as_u64[1];
 172             }
 173
 174           sw_if_index0 = adj0->rewrite_header.sw_if_index;
 175           vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
 176
 177           /* combine the address and interface for a hash */
 178           r0 = ip6_address_hash_to_u64 (&ip0->dst_address) ^ sw_if_index0;
 179
 180           drop0 = throttle_check (&nd_throttle, thread_index, r0, seed);
 181
 182           from += 1;
 183           n_left_from -= 1;
 184           to_next_drop[0] = pi0;
 185           to_next_drop += 1;
 186           n_left_to_next_drop -= 1;
 187
 188           if (drop0)
 189             {
 190               p0->error = node->errors[IP6_NEIGHBOR_ERROR_THROTTLED];
 191               continue;
 192             }
 193
 194           hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
 195
 196           /* If the interface is link-down, drop the pkt */
 197           if (!(hw_if0->flags & VNET_HW_INTERFACE_FLAG_LINK_UP))
 198             drop0 = 1;
 199
 200           if (!ip6_link_is_enabled (sw_if_index0))
 201             drop0 = 1;
 202
 203           /*
 204            * the adj has been updated to a rewrite but the node the DPO that got
 205            * us here hasn't - yet. no big deal. we'll drop while we wait.
 206            */
 207           if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
 208             drop0 = 1;
 209
 210           if (drop0)
 211             {
 212               p0->error = node->errors[IP6_NEIGHBOR_ERROR_DROP];
 213               continue;
 214             }
 215
 216           /*
 217            * Choose source address based on destination lookup
 218            * adjacency.
 219            */
 220           const ip6_address_t *ll = ip6_get_link_local_address (sw_if_index0);
 221           if (!ll)
 222             {
 223               /* There is no address on the interface */
 224               p0->error = node->errors[IP6_NEIGHBOR_ERROR_NO_SOURCE_ADDRESS];
 225               continue;
 226             }
 227           ip6_address_copy (&src, ll);
 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_NEIGHBOR_ERROR_REQUEST_SENT];
 239             }
 240           else
 241             {
 242               /* There is no address on the interface */
 243               p0->error = node->errors[IP6_NEIGHBOR_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 VLIB_REGISTER_NODE (ip6_glean_node) =
 268 {
 269   .function = ip6_glean,
 270   .name = "ip6-glean",
 271   .vector_size = sizeof (u32),
 272   .format_trace = format_ip6_forward_next_trace,
 273   .n_errors = IP6_NEIGHBOR_N_ERROR,
 274   .error_counters = ip6_neighbor_error_counters,
 275   .n_next_nodes = IP6_NBR_N_NEXT,
 276   .next_nodes =
 277   {
 278     [IP6_NBR_NEXT_DROP] = "ip6-drop",
 279     [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
 280   },
 281 };
 282 VLIB_REGISTER_NODE (ip6_discover_neighbor_node) =
 283 {
 284   .function = ip6_discover_neighbor,
 285   .name = "ip6-discover-neighbor",
 286   .vector_size = sizeof (u32),
 287   .format_trace = format_ip6_forward_next_trace,
 288   .n_errors = IP6_NEIGHBOR_N_ERROR,
 289   .error_counters = ip6_neighbor_error_counters,
 290   .n_next_nodes = IP6_NBR_N_NEXT,
 291   .next_nodes =
 292   {
 293     [IP6_NBR_NEXT_DROP] = "ip6-drop",
 294     [IP6_NBR_NEXT_REPLY_TX] = "ip6-rewrite-mcast",
 295   },
 296 };
 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, THROTTLE_BITS, 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  */