src/vnet/ip-neighbor/ip4_neighbor.c

   1 /*
   2  * Copyright (c) 2015 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 /*
  16  * ip/ip4_forward.c: IP v4 forwarding
  17  *
  18  * Copyright (c) 2008 Eliot Dresselhaus
  19  *
  20  * Permission is hereby granted, free of charge, to any person obtaining
  21  * a copy of this software and associated documentation files (the
  22  * "Software"), to deal in the Software without restriction, including
  23  * without limitation the rights to use, copy, modify, merge, publish,
  24  * distribute, sublicense, and/or sell copies of the Software, and to
  25  * permit persons to whom the Software is furnished to do so, subject to
  26  * the following conditions:
  27  *
  28  * The above copyright notice and this permission notice shall be
  29  * included in all copies or substantial portions of the Software.
  30  *
  31  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  32  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  33  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  34  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  35  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  36  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  37  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  38  */
  39
  40 #include <vnet/ip-neighbor/ip4_neighbor.h>
  41 #include <vnet/ethernet/ethernet.h>
  42
  43 void
  44 ip4_neighbor_probe_dst (const ip_adjacency_t * adj, const ip4_address_t * dst)
  45 {
  46   ip_interface_address_t *ia;
  47   ip4_address_t *src;
  48
  49   src = ip4_interface_address_matching_destination
  50     (&ip4_main,
  51      &adj->sub_type.nbr.next_hop.ip4, adj->rewrite_header.sw_if_index, &ia);
  52   if (!src)
  53     return;
  54
  55   ip4_neighbor_probe (vlib_get_main (), vnet_get_main (), adj, src, dst);
  56 }
  57
  58 void
  59 ip4_neighbor_advertise (vlib_main_t * vm,
  60                         vnet_main_t * vnm,
  61                         u32 sw_if_index, const ip4_address_t * addr)
  62 {
  63   vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
  64   ip4_main_t *i4m = &ip4_main;
  65   u8 *rewrite, rewrite_len;
  66
  67   if (NULL == addr)
  68     {
  69       ip4_main_t *i4m = &ip4_main;
  70       addr = ip4_interface_first_address (i4m, sw_if_index, 0);
  71     }
  72
  73   if (addr)
  74     {
  75       clib_warning ("Sending GARP for IP4 address %U on sw_if_idex %d",
  76                     format_ip4_address, addr, sw_if_index);
  77
  78       /* Form GARP packet for output - Gratuitous ARP is an ARP request packet
  79          where the interface IP/MAC pair is used for both source and request
  80          MAC/IP pairs in the request */
  81       u32 bi = 0;
  82       ethernet_arp_header_t *h = vlib_packet_template_get_packet
  83         (vm, &i4m->ip4_arp_request_packet_template, &bi);
  84
  85       if (!h)
  86         return;
  87
  88       mac_address_from_bytes (&h->ip4_over_ethernet[0].mac, hi->hw_address);
  89       mac_address_from_bytes (&h->ip4_over_ethernet[1].mac, hi->hw_address);
  90       h->ip4_over_ethernet[0].ip4 = addr[0];
  91       h->ip4_over_ethernet[1].ip4 = addr[0];
  92
  93       /* Setup MAC header with ARP Etype and broadcast DMAC */
  94       vlib_buffer_t *b = vlib_get_buffer (vm, bi);
  95       rewrite =
  96         ethernet_build_rewrite (vnm, sw_if_index, VNET_LINK_ARP,
  97                                 VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST);
  98       rewrite_len = vec_len (rewrite);
  99       vlib_buffer_advance (b, -rewrite_len);
 100       ethernet_header_t *e = vlib_buffer_get_current (b);
 101       clib_memcpy_fast (e->dst_address, rewrite, rewrite_len);
 102       vec_free (rewrite);
 103
 104       /* Send GARP packet out the specified interface */
 105       vnet_buffer (b)->sw_if_index[VLIB_RX] =
 106         vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;
 107       vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
 108       u32 *to_next = vlib_frame_vector_args (f);
 109       to_next[0] = bi;
 110       f->n_vectors = 1;
 111       vlib_put_frame_to_node (vm, hi->output_node_index, f);
 112     }
 113 }
 114
 115 always_inline uword
 116 ip4_arp_inline (vlib_main_t * vm,
 117                 vlib_node_runtime_t * node,
 118                 vlib_frame_t * frame, int is_glean)
 119 {
 120   vnet_main_t *vnm = vnet_get_main ();
 121   ip4_main_t *im = &ip4_main;
 122   ip_lookup_main_t *lm = &im->lookup_main;
 123   u32 *from, *to_next_drop;
 124   uword n_left_from, n_left_to_next_drop, next_index;
 125   u32 thread_index = vm->thread_index;
 126   u64 seed;
 127
 128   if (node->flags & VLIB_NODE_FLAG_TRACE)
 129     ip4_forward_next_trace (vm, node, frame, VLIB_TX);
 130
 131   seed = throttle_seed (&im->arp_throttle, thread_index, vlib_time_now (vm));
 132
 133   from = vlib_frame_vector_args (frame);
 134   n_left_from = frame->n_vectors;
 135   next_index = node->cached_next_index;
 136   if (next_index == IP4_ARP_NEXT_DROP)
 137     next_index = IP4_ARP_N_NEXT;        /* point to first interface */
 138
 139   while (n_left_from > 0)
 140     {
 141       vlib_get_next_frame (vm, node, IP4_ARP_NEXT_DROP,
 142                            to_next_drop, n_left_to_next_drop);
 143
 144       while (n_left_from > 0 && n_left_to_next_drop > 0)
 145         {
 146           u32 pi0, adj_index0, sw_if_index0;
 147           ip4_address_t resolve0, src0;
 148           vlib_buffer_t *p0, *b0;
 149           ip_adjacency_t *adj0;
 150           u64 r0;
 151
 152           pi0 = from[0];
 153           p0 = vlib_get_buffer (vm, pi0);
 154
 155           from += 1;
 156           n_left_from -= 1;
 157           to_next_drop[0] = pi0;
 158           to_next_drop += 1;
 159           n_left_to_next_drop -= 1;
 160
 161           adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
 162           adj0 = adj_get (adj_index0);
 163           sw_if_index0 = adj0->rewrite_header.sw_if_index;
 164
 165           if (is_glean)
 166             {
 167               /* resolve the packet's destination */
 168               ip4_header_t *ip0 = vlib_buffer_get_current (p0);
 169               resolve0 = ip0->dst_address;
 170               src0 = adj0->sub_type.glean.receive_addr.ip4;
 171             }
 172           else
 173             {
 174               /* resolve the incomplete adj */
 175               resolve0 = adj0->sub_type.nbr.next_hop.ip4;
 176               /* Src IP address in ARP header. */
 177               if (ip4_src_address_for_packet (lm, sw_if_index0, &src0))
 178                 {
 179                   /* No source address available */
 180                   p0->error = node->errors[IP4_ARP_ERROR_NO_SOURCE_ADDRESS];
 181                   continue;
 182                 }
 183             }
 184
 185           /* combine the address and interface for the hash key */
 186           r0 = (u64) resolve0.data_u32 << 32;
 187           r0 |= sw_if_index0;
 188
 189           if (throttle_check (&im->arp_throttle, thread_index, r0, seed))
 190             {
 191               p0->error = node->errors[IP4_ARP_ERROR_THROTTLED];
 192               continue;
 193             }
 194
 195           /*
 196            * the adj has been updated to a rewrite but the node the DPO that got
 197            * us here hasn't - yet. no big deal. we'll drop while we wait.
 198            */
 199           if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
 200             {
 201               p0->error = node->errors[IP4_ARP_ERROR_RESOLVED];
 202               continue;
 203             }
 204
 205           /*
 206            * Can happen if the control-plane is programming tables
 207            * with traffic flowing; at least that's today's lame excuse.
 208            */
 209           if ((is_glean && adj0->lookup_next_index != IP_LOOKUP_NEXT_GLEAN)
 210               || (!is_glean && adj0->lookup_next_index != IP_LOOKUP_NEXT_ARP))
 211             {
 212               p0->error = node->errors[IP4_ARP_ERROR_NON_ARP_ADJ];
 213               continue;
 214             }
 215
 216           /* Send ARP request. */
 217           b0 = ip4_neighbor_probe (vm, vnm, adj0, &src0, &resolve0);
 218
 219           if (PREDICT_TRUE (NULL != b0))
 220             {
 221               /* copy the persistent fields from the original */
 222               clib_memcpy_fast (b0->opaque2, p0->opaque2,
 223                                 sizeof (p0->opaque2));
 224               p0->error = node->errors[IP4_ARP_ERROR_REQUEST_SENT];
 225             }
 226           else
 227             {
 228               p0->error = node->errors[IP4_ARP_ERROR_NO_BUFFERS];
 229               continue;
 230             }
 231         }
 232
 233       vlib_put_next_frame (vm, node, IP4_ARP_NEXT_DROP, n_left_to_next_drop);
 234     }
 235
 236   return frame->n_vectors;
 237 }
 238
 239 VLIB_NODE_FN (ip4_arp_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
 240                              vlib_frame_t * frame)
 241 {
 242   return (ip4_arp_inline (vm, node, frame, 0));
 243 }
 244
 245 VLIB_NODE_FN (ip4_glean_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
 246                                vlib_frame_t * frame)
 247 {
 248   return (ip4_arp_inline (vm, node, frame, 1));
 249 }
 250
 251 static char *ip4_arp_error_strings[] = {
 252   [IP4_ARP_ERROR_THROTTLED] = "ARP requests throttled",
 253   [IP4_ARP_ERROR_RESOLVED] = "ARP requests resolved",
 254   [IP4_ARP_ERROR_NO_BUFFERS] = "ARP requests out of buffer",
 255   [IP4_ARP_ERROR_REQUEST_SENT] = "ARP requests sent",
 256   [IP4_ARP_ERROR_NON_ARP_ADJ] = "ARPs to non-ARP adjacencies",
 257   [IP4_ARP_ERROR_NO_SOURCE_ADDRESS] = "no source address for ARP request",
 258 };
 259
 260 /* *INDENT-OFF* */
 261 VLIB_REGISTER_NODE (ip4_arp_node) =
 262 {
 263   .name = "ip4-arp",
 264   .vector_size = sizeof (u32),
 265   .format_trace = format_ip4_forward_next_trace,
 266   .n_errors = ARRAY_LEN (ip4_arp_error_strings),
 267   .error_strings = ip4_arp_error_strings,
 268   .n_next_nodes = IP4_ARP_N_NEXT,
 269   .next_nodes = {
 270     [IP4_ARP_NEXT_DROP] = "ip4-drop",
 271   },
 272 };
 273
 274 VLIB_REGISTER_NODE (ip4_glean_node) =
 275 {
 276   .name = "ip4-glean",
 277   .vector_size = sizeof (u32),
 278   .format_trace = format_ip4_forward_next_trace,
 279   .n_errors = ARRAY_LEN (ip4_arp_error_strings),
 280   .error_strings = ip4_arp_error_strings,
 281   .n_next_nodes = IP4_ARP_N_NEXT,
 282   .next_nodes = {
 283     [IP4_ARP_NEXT_DROP] = "ip4-drop",
 284   },
 285 };
 286 /* *INDENT-ON* */
 287
 288 #define foreach_notrace_ip4_arp_error           \
 289 _(THROTTLED)                                    \
 290 _(RESOLVED)                                     \
 291 _(NO_BUFFERS)                                   \
 292 _(REQUEST_SENT)                                 \
 293 _(NON_ARP_ADJ)                                  \
 294 _(NO_SOURCE_ADDRESS)
 295
 296 static clib_error_t *
 297 arp_notrace_init (vlib_main_t * vm)
 298 {
 299   vlib_node_runtime_t *rt = vlib_node_get_runtime (vm, ip4_arp_node.index);
 300
 301   /* don't trace ARP request packets */
 302 #define _(a)                                    \
 303     vnet_pcap_drop_trace_filter_add_del         \
 304         (rt->errors[IP4_ARP_ERROR_##a],         \
 305          1 /* is_add */);
 306   foreach_notrace_ip4_arp_error;
 307 #undef _
 308   return 0;
 309 }
 310
 311 VLIB_INIT_FUNCTION (arp_notrace_init);
 312
 313 /*
 314  * fd.io coding-style-patch-verification: ON
 315  *
 316  * Local Variables:
 317  * eval: (c-set-style "gnu")
 318  * End:
 319  */