src/vnet/devices/af_packet/node.c

   1 /*
   2  *------------------------------------------------------------------
   3  * af_packet.c - linux kernel packet interface
   4  *
   5  * Copyright (c) 2016 Cisco and/or its affiliates.
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at:
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  *------------------------------------------------------------------
  18  */
  19
  20 #include <linux/if_packet.h>
  21
  22 #include <vlib/vlib.h>
  23 #include <vlib/unix/unix.h>
  24 #include <vnet/ip/ip.h>
  25 #include <vnet/ethernet/ethernet.h>
  26 #include <vnet/interface/rx_queue_funcs.h>
  27 #include <vnet/feature/feature.h>
  28 #include <vnet/ethernet/packet.h>
  29
  30 #include <vnet/devices/af_packet/af_packet.h>
  31
  32 #define foreach_af_packet_input_error \
  33   _(PARTIAL_PKT, "partial packet")
  34
  35 typedef enum
  36 {
  37 #define _(f,s) AF_PACKET_INPUT_ERROR_##f,
  38   foreach_af_packet_input_error
  39 #undef _
  40     AF_PACKET_INPUT_N_ERROR,
  41 } af_packet_input_error_t;
  42
  43 static char *af_packet_input_error_strings[] = {
  44 #define _(n,s) s,
  45   foreach_af_packet_input_error
  46 #undef _
  47 };
  48
  49 typedef struct
  50 {
  51   u32 next_index;
  52   u32 hw_if_index;
  53   int block;
  54   struct tpacket2_hdr tph;
  55 } af_packet_input_trace_t;
  56
  57 static u8 *
  58 format_af_packet_input_trace (u8 * s, va_list * args)
  59 {
  60   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  61   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  62   af_packet_input_trace_t *t = va_arg (*args, af_packet_input_trace_t *);
  63   u32 indent = format_get_indent (s);
  64
  65   s = format (s, "af_packet: hw_if_index %d next-index %d",
  66               t->hw_if_index, t->next_index);
  67
  68   s =
  69     format (s,
  70             "\n%Utpacket2_hdr:\n%Ustatus 0x%x len %u snaplen %u mac %u net %u"
  71             "\n%Usec 0x%x nsec 0x%x vlan %U"
  72 #ifdef TP_STATUS_VLAN_TPID_VALID
  73             " vlan_tpid %u"
  74 #endif
  75             ,
  76             format_white_space, indent + 2,
  77             format_white_space, indent + 4,
  78             t->tph.tp_status,
  79             t->tph.tp_len,
  80             t->tph.tp_snaplen,
  81             t->tph.tp_mac,
  82             t->tph.tp_net,
  83             format_white_space, indent + 4,
  84             t->tph.tp_sec,
  85             t->tph.tp_nsec, format_ethernet_vlan_tci, t->tph.tp_vlan_tci
  86 #ifdef TP_STATUS_VLAN_TPID_VALID
  87             , t->tph.tp_vlan_tpid
  88 #endif
  89     );
  90   return s;
  91 }
  92
  93 always_inline void
  94 buffer_add_to_chain (vlib_main_t * vm, u32 bi, u32 first_bi, u32 prev_bi)
  95 {
  96   vlib_buffer_t *b = vlib_get_buffer (vm, bi);
  97   vlib_buffer_t *first_b = vlib_get_buffer (vm, first_bi);
  98   vlib_buffer_t *prev_b = vlib_get_buffer (vm, prev_bi);
  99
 100   /* update first buffer */
 101   first_b->total_length_not_including_first_buffer += b->current_length;
 102
 103   /* update previous buffer */
 104   prev_b->next_buffer = bi;
 105   prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
 106
 107   /* update current buffer */
 108   b->next_buffer = 0;
 109 }
 110
 111 static_always_inline void
 112 fill_gso_buffer_flags (vlib_buffer_t *b, u32 gso_size, u8 l4_hdr_sz)
 113 {
 114   b->flags |= VNET_BUFFER_F_GSO;
 115   vnet_buffer2 (b)->gso_size = gso_size;
 116   vnet_buffer2 (b)->gso_l4_hdr_sz = l4_hdr_sz;
 117 }
 118
 119 static_always_inline void
 120 mark_tcp_udp_cksum_calc (vlib_buffer_t *b, u8 *l4_hdr_sz)
 121 {
 122   ethernet_header_t *eth = vlib_buffer_get_current (b);
 123   vnet_buffer_oflags_t oflags = 0;
 124   if (clib_net_to_host_u16 (eth->type) == ETHERNET_TYPE_IP4)
 125     {
 126       ip4_header_t *ip4 =
 127         (vlib_buffer_get_current (b) + sizeof (ethernet_header_t));
 128       b->flags |= VNET_BUFFER_F_IS_IP4;
 129       if (ip4->protocol == IP_PROTOCOL_TCP)
 130         {
 131           oflags |= VNET_BUFFER_OFFLOAD_F_TCP_CKSUM;
 132           tcp_header_t *tcp = (tcp_header_t *) (vlib_buffer_get_current (b) +
 133                                                 sizeof (ethernet_header_t) +
 134                                                 ip4_header_bytes (ip4));
 135           *l4_hdr_sz = tcp_header_bytes (tcp);
 136         }
 137       else if (ip4->protocol == IP_PROTOCOL_UDP)
 138         {
 139           oflags |= VNET_BUFFER_OFFLOAD_F_UDP_CKSUM;
 140           udp_header_t *udp = (udp_header_t *) (vlib_buffer_get_current (b) +
 141                                                 sizeof (ethernet_header_t) +
 142                                                 ip4_header_bytes (ip4));
 143           *l4_hdr_sz = sizeof (*udp);
 144         }
 145       vnet_buffer (b)->l3_hdr_offset = sizeof (ethernet_header_t);
 146       vnet_buffer (b)->l4_hdr_offset =
 147         sizeof (ethernet_header_t) + ip4_header_bytes (ip4);
 148       if (oflags)
 149         vnet_buffer_offload_flags_set (b, oflags);
 150     }
 151   else if (clib_net_to_host_u16 (eth->type) == ETHERNET_TYPE_IP6)
 152     {
 153       ip6_header_t *ip6 =
 154         (vlib_buffer_get_current (b) + sizeof (ethernet_header_t));
 155       b->flags |= VNET_BUFFER_F_IS_IP6;
 156       u16 ip6_hdr_len = sizeof (ip6_header_t);
 157       if (ip6_ext_hdr (ip6->protocol))
 158         {
 159           ip6_ext_header_t *p = (void *) (ip6 + 1);
 160           ip6_hdr_len += ip6_ext_header_len (p);
 161           while (ip6_ext_hdr (p->next_hdr))
 162             {
 163               ip6_hdr_len += ip6_ext_header_len (p);
 164               p = ip6_ext_next_header (p);
 165             }
 166         }
 167       if (ip6->protocol == IP_PROTOCOL_TCP)
 168         {
 169           oflags |= VNET_BUFFER_OFFLOAD_F_TCP_CKSUM;
 170           tcp_header_t *tcp =
 171             (tcp_header_t *) (vlib_buffer_get_current (b) +
 172                               sizeof (ethernet_header_t) + ip6_hdr_len);
 173           *l4_hdr_sz = tcp_header_bytes (tcp);
 174         }
 175       else if (ip6->protocol == IP_PROTOCOL_UDP)
 176         {
 177           oflags |= VNET_BUFFER_OFFLOAD_F_UDP_CKSUM;
 178           udp_header_t *udp =
 179             (udp_header_t *) (vlib_buffer_get_current (b) +
 180                               sizeof (ethernet_header_t) + ip6_hdr_len);
 181           *l4_hdr_sz = sizeof (*udp);
 182         }
 183       vnet_buffer (b)->l3_hdr_offset = sizeof (ethernet_header_t);
 184       vnet_buffer (b)->l4_hdr_offset =
 185         sizeof (ethernet_header_t) + ip6_hdr_len;
 186       if (oflags)
 187         vnet_buffer_offload_flags_set (b, oflags);
 188     }
 189 }
 190
 191 always_inline uword
 192 af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 193                            vlib_frame_t * frame, af_packet_if_t * apif)
 194 {
 195   af_packet_main_t *apm = &af_packet_main;
 196   struct tpacket2_hdr *tph;
 197   u32 next_index;
 198   u32 block = 0;
 199   u32 rx_frame;
 200   u32 n_free_bufs;
 201   u32 n_rx_packets = 0;
 202   u32 n_rx_bytes = 0;
 203   u32 *to_next = 0;
 204   u32 block_size = apif->rx_req->tp_block_size;
 205   u32 frame_size = apif->rx_req->tp_frame_size;
 206   u32 frame_num = apif->rx_req->tp_frame_nr;
 207   u8 *block_start = apif->rx_ring + block * block_size;
 208   uword n_trace = vlib_get_trace_count (vm, node);
 209   u32 thread_index = vm->thread_index;
 210   u32 n_buffer_bytes = vlib_buffer_get_default_data_size (vm);
 211   u32 min_bufs = apif->rx_req->tp_frame_size / n_buffer_bytes;
 212   u32 eth_header_size = 0;
 213   vlib_buffer_t bt;
 214
 215   if (apif->mode == AF_PACKET_IF_MODE_IP)
 216     {
 217       next_index = VNET_DEVICE_INPUT_NEXT_IP4_INPUT;
 218     }
 219   else
 220     {
 221       eth_header_size = sizeof (ethernet_header_t);
 222       next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
 223       if (PREDICT_FALSE (apif->per_interface_next_index != ~0))
 224         next_index = apif->per_interface_next_index;
 225
 226       /* redirect if feature path enabled */
 227       vnet_feature_start_device_input_x1 (apif->sw_if_index, &next_index, &bt);
 228     }
 229
 230   n_free_bufs = vec_len (apm->rx_buffers[thread_index]);
 231   if (PREDICT_FALSE (n_free_bufs < VLIB_FRAME_SIZE))
 232     {
 233       vec_validate (apm->rx_buffers[thread_index],
 234                     VLIB_FRAME_SIZE + n_free_bufs - 1);
 235       n_free_bufs +=
 236         vlib_buffer_alloc (vm, &apm->rx_buffers[thread_index][n_free_bufs],
 237                            VLIB_FRAME_SIZE);
 238       _vec_len (apm->rx_buffers[thread_index]) = n_free_bufs;
 239     }
 240
 241   rx_frame = apif->next_rx_frame;
 242   tph = (struct tpacket2_hdr *) (block_start + rx_frame * frame_size);
 243   while ((tph->tp_status & TP_STATUS_USER) && (n_free_bufs > min_bufs))
 244     {
 245       vlib_buffer_t *b0 = 0, *first_b0 = 0;
 246       u32 next0 = next_index;
 247
 248       u32 n_left_to_next;
 249       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 250       while ((tph->tp_status & TP_STATUS_USER) && (n_free_bufs > min_bufs) &&
 251              n_left_to_next)
 252         {
 253           u32 data_len = tph->tp_snaplen;
 254           u32 offset = 0;
 255           u32 bi0 = 0, first_bi0 = 0, prev_bi0;
 256           u8 l4_hdr_sz = 0;
 257
 258           while (data_len)
 259             {
 260               /* grab free buffer */
 261               u32 last_empty_buffer =
 262                 vec_len (apm->rx_buffers[thread_index]) - 1;
 263               prev_bi0 = bi0;
 264               bi0 = apm->rx_buffers[thread_index][last_empty_buffer];
 265               b0 = vlib_get_buffer (vm, bi0);
 266               _vec_len (apm->rx_buffers[thread_index]) = last_empty_buffer;
 267               n_free_bufs--;
 268
 269               /* copy data */
 270               u32 bytes_to_copy =
 271                 data_len > n_buffer_bytes ? n_buffer_bytes : data_len;
 272               u32 vlan_len = 0;
 273               u32 bytes_copied = 0;
 274               b0->current_data = 0;
 275               /* Kernel removes VLAN headers, so reconstruct VLAN */
 276               if (PREDICT_FALSE (tph->tp_status & TP_STATUS_VLAN_VALID))
 277                 {
 278                   if (PREDICT_TRUE (offset == 0))
 279                     {
 280                       clib_memcpy_fast (vlib_buffer_get_current (b0),
 281                                         (u8 *) tph + tph->tp_mac,
 282                                         sizeof (ethernet_header_t));
 283                       ethernet_header_t *eth = vlib_buffer_get_current (b0);
 284                       ethernet_vlan_header_t *vlan =
 285                         (ethernet_vlan_header_t *) (eth + 1);
 286                       vlan->priority_cfi_and_id =
 287                         clib_host_to_net_u16 (tph->tp_vlan_tci);
 288                       vlan->type = eth->type;
 289                       eth->type = clib_host_to_net_u16 (ETHERNET_TYPE_VLAN);
 290                       vlan_len = sizeof (ethernet_vlan_header_t);
 291                       bytes_copied = sizeof (ethernet_header_t);
 292                     }
 293                 }
 294               clib_memcpy_fast (((u8 *) vlib_buffer_get_current (b0)) +
 295                                 bytes_copied + vlan_len,
 296                                 (u8 *) tph + tph->tp_mac + offset +
 297                                 bytes_copied, (bytes_to_copy - bytes_copied));
 298
 299               /* fill buffer header */
 300               b0->current_length = bytes_to_copy + vlan_len;
 301
 302               if (offset == 0)
 303                 {
 304                   b0->total_length_not_including_first_buffer = 0;
 305                   b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 306                   vnet_buffer (b0)->sw_if_index[VLIB_RX] = apif->sw_if_index;
 307                   vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 308                   first_bi0 = bi0;
 309                   first_b0 = vlib_get_buffer (vm, first_bi0);
 310                   if (tph->tp_status & TP_STATUS_CSUMNOTREADY)
 311                     mark_tcp_udp_cksum_calc (first_b0, &l4_hdr_sz);
 312                   /* This is a trade-off for GSO. As kernel isn't passing
 313                    * us the GSO state or size, we guess it by comparing it
 314                    * to the host MTU of the interface */
 315                   if (tph->tp_snaplen > (apif->host_mtu + eth_header_size))
 316                     fill_gso_buffer_flags (first_b0, apif->host_mtu,
 317                                            l4_hdr_sz);
 318                 }
 319               else
 320                 buffer_add_to_chain (vm, bi0, first_bi0, prev_bi0);
 321
 322               offset += bytes_to_copy;
 323               data_len -= bytes_to_copy;
 324             }
 325           n_rx_packets++;
 326           n_rx_bytes += tph->tp_snaplen;
 327           to_next[0] = first_bi0;
 328           to_next += 1;
 329           n_left_to_next--;
 330
 331           /* drop partial packets */
 332           if (PREDICT_FALSE (tph->tp_len != tph->tp_snaplen))
 333             {
 334               next0 = VNET_DEVICE_INPUT_NEXT_DROP;
 335               first_b0->error =
 336                 node->errors[AF_PACKET_INPUT_ERROR_PARTIAL_PKT];
 337             }
 338           else
 339             {
 340               if (PREDICT_FALSE (apif->mode == AF_PACKET_IF_MODE_IP))
 341                 {
 342                   switch (first_b0->data[0] & 0xf0)
 343                     {
 344                     case 0x40:
 345                       next0 = VNET_DEVICE_INPUT_NEXT_IP4_INPUT;
 346                       break;
 347                     case 0x60:
 348                       next0 = VNET_DEVICE_INPUT_NEXT_IP6_INPUT;
 349                       break;
 350                     default:
 351                       next0 = VNET_DEVICE_INPUT_NEXT_DROP;
 352                       break;
 353                     }
 354                   if (PREDICT_FALSE (apif->per_interface_next_index != ~0))
 355                     next0 = apif->per_interface_next_index;
 356                 }
 357               else
 358                 {
 359                   /* copy feature arc data from template */
 360                   first_b0->current_config_index = bt.current_config_index;
 361                   vnet_buffer (first_b0)->feature_arc_index =
 362                     vnet_buffer (&bt)->feature_arc_index;
 363                 }
 364             }
 365
 366           /* trace */
 367           if (PREDICT_FALSE
 368               (n_trace > 0 && vlib_trace_buffer (vm, node, next0, first_b0,
 369                                                  /* follow_chain */ 0)))
 370             {
 371               af_packet_input_trace_t *tr;
 372               vlib_set_trace_count (vm, node, --n_trace);
 373               tr = vlib_add_trace (vm, node, first_b0, sizeof (*tr));
 374               tr->next_index = next0;
 375               tr->hw_if_index = apif->hw_if_index;
 376               clib_memcpy_fast (&tr->tph, tph, sizeof (struct tpacket2_hdr));
 377             }
 378
 379           /* enque and take next packet */
 380           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 381                                            n_left_to_next, first_bi0, next0);
 382
 383           /* next packet */
 384           tph->tp_status = TP_STATUS_KERNEL;
 385           rx_frame = (rx_frame + 1) % frame_num;
 386           tph = (struct tpacket2_hdr *) (block_start + rx_frame * frame_size);
 387         }
 388
 389       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 390     }
 391
 392   apif->next_rx_frame = rx_frame;
 393
 394   vlib_increment_combined_counter
 395     (vnet_get_main ()->interface_main.combined_sw_if_counters
 396      + VNET_INTERFACE_COUNTER_RX,
 397      vlib_get_thread_index (), apif->hw_if_index, n_rx_packets, n_rx_bytes);
 398
 399   vnet_device_increment_rx_packets (thread_index, n_rx_packets);
 400   return n_rx_packets;
 401 }
 402
 403 VLIB_NODE_FN (af_packet_input_node) (vlib_main_t * vm,
 404                                      vlib_node_runtime_t * node,
 405                                      vlib_frame_t * frame)
 406 {
 407   u32 n_rx_packets = 0;
 408   af_packet_main_t *apm = &af_packet_main;
 409   vnet_hw_if_rxq_poll_vector_t *pv;
 410   pv = vnet_hw_if_get_rxq_poll_vector (vm, node);
 411   for (int i = 0; i < vec_len (pv); i++)
 412     {
 413       af_packet_if_t *apif;
 414       apif = vec_elt_at_index (apm->interfaces, pv[i].dev_instance);
 415       if (apif->is_admin_up)
 416         n_rx_packets += af_packet_device_input_fn (vm, node, frame, apif);
 417     }
 418
 419   return n_rx_packets;
 420 }
 421
 422 VLIB_REGISTER_NODE (af_packet_input_node) = {
 423   .name = "af-packet-input",
 424   .flags = VLIB_NODE_FLAG_TRACE_SUPPORTED,
 425   .sibling_of = "device-input",
 426   .format_trace = format_af_packet_input_trace,
 427   .type = VLIB_NODE_TYPE_INPUT,
 428   .state = VLIB_NODE_STATE_INTERRUPT,
 429   .n_errors = AF_PACKET_INPUT_N_ERROR,
 430   .error_strings = af_packet_input_error_strings,
 431 };
 432
 433
 434 /*
 435  * fd.io coding-style-patch-verification: ON
 436  *
 437  * Local Variables:
 438  * eval: (c-set-style "gnu")
 439  * End:
 440  */