src/vnet/devices/af_packet/node.c

   1 /*------------------------------------------------------------------
   2  * af_packet.c - linux kernel packet interface
   3  *
   4  * Copyright (c) 2016 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
  19 #include <linux/if_packet.h>
  20 #include <linux/virtio_net.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/devices/devices.h>
  27 #include <vnet/feature/feature.h>
  28
  29 #include <vnet/devices/af_packet/af_packet.h>
  30
  31 #define foreach_af_packet_input_error
  32
  33 typedef enum
  34 {
  35 #define _(f,s) AF_PACKET_INPUT_ERROR_##f,
  36   foreach_af_packet_input_error
  37 #undef _
  38     AF_PACKET_INPUT_N_ERROR,
  39 } af_packet_input_error_t;
  40
  41 static char *af_packet_input_error_strings[] = {
  42 #define _(n,s) s,
  43   foreach_af_packet_input_error
  44 #undef _
  45 };
  46
  47 typedef struct
  48 {
  49   u32 next_index;
  50   u32 hw_if_index;
  51   int block;
  52   struct tpacket2_hdr tph;
  53 } af_packet_input_trace_t;
  54
  55 static u8 *
  56 format_af_packet_input_trace (u8 * s, va_list * args)
  57 {
  58   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  59   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  60   af_packet_input_trace_t *t = va_arg (*args, af_packet_input_trace_t *);
  61   u32 indent = format_get_indent (s);
  62
  63   s = format (s, "af_packet: hw_if_index %d next-index %d",
  64               t->hw_if_index, t->next_index);
  65
  66   s =
  67     format (s,
  68             "\n%Utpacket2_hdr:\n%Ustatus 0x%x len %u snaplen %u mac %u net %u"
  69             "\n%Usec 0x%x nsec 0x%x vlan %U"
  70 #ifdef TP_STATUS_VLAN_TPID_VALID
  71             " vlan_tpid %u"
  72 #endif
  73             ,
  74             format_white_space, indent + 2,
  75             format_white_space, indent + 4,
  76             t->tph.tp_status,
  77             t->tph.tp_len,
  78             t->tph.tp_snaplen,
  79             t->tph.tp_mac,
  80             t->tph.tp_net,
  81             format_white_space, indent + 4,
  82             t->tph.tp_sec,
  83             t->tph.tp_nsec, format_ethernet_vlan_tci, t->tph.tp_vlan_tci
  84 #ifdef TP_STATUS_VLAN_TPID_VALID
  85             , t->tph.tp_vlan_tpid
  86 #endif
  87     );
  88   return s;
  89 }
  90
  91 always_inline void
  92 buffer_add_to_chain (vlib_main_t * vm, u32 bi, u32 first_bi, u32 prev_bi)
  93 {
  94   vlib_buffer_t *b = vlib_get_buffer (vm, bi);
  95   vlib_buffer_t *first_b = vlib_get_buffer (vm, first_bi);
  96   vlib_buffer_t *prev_b = vlib_get_buffer (vm, prev_bi);
  97
  98   /* update first buffer */
  99   first_b->total_length_not_including_first_buffer += b->current_length;
 100
 101   /* update previous buffer */
 102   prev_b->next_buffer = bi;
 103   prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
 104
 105   /* update current buffer */
 106   b->next_buffer = 0;
 107 }
 108
 109 always_inline uword
 110 af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 111                            vlib_frame_t * frame, af_packet_if_t * apif)
 112 {
 113   af_packet_main_t *apm = &af_packet_main;
 114   struct tpacket2_hdr *tph;
 115   u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
 116   u32 block = 0;
 117   u32 rx_frame;
 118   u32 n_free_bufs;
 119   u32 n_rx_packets = 0;
 120   u32 n_rx_bytes = 0;
 121   u32 *to_next = 0;
 122   u32 block_size = apif->rx_req->tp_block_size;
 123   u32 frame_size = apif->rx_req->tp_frame_size;
 124   u32 frame_num = apif->rx_req->tp_frame_nr;
 125   u8 *block_start = apif->rx_ring + block * block_size;
 126   uword n_trace = vlib_get_trace_count (vm, node);
 127   u32 thread_index = vlib_get_thread_index ();
 128   u32 n_buffer_bytes = vlib_buffer_free_list_buffer_size (vm,
 129                                                           VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
 130   u32 min_bufs = apif->rx_req->tp_frame_size / n_buffer_bytes;
 131
 132   if (apif->per_interface_next_index != ~0)
 133     next_index = apif->per_interface_next_index;
 134
 135   n_free_bufs = vec_len (apm->rx_buffers[thread_index]);
 136   if (PREDICT_FALSE (n_free_bufs < VLIB_FRAME_SIZE))
 137     {
 138       vec_validate (apm->rx_buffers[thread_index],
 139                     VLIB_FRAME_SIZE + n_free_bufs - 1);
 140       n_free_bufs +=
 141         vlib_buffer_alloc (vm, &apm->rx_buffers[thread_index][n_free_bufs],
 142                            VLIB_FRAME_SIZE);
 143       _vec_len (apm->rx_buffers[thread_index]) = n_free_bufs;
 144     }
 145
 146   rx_frame = apif->next_rx_frame;
 147   tph = (struct tpacket2_hdr *) (block_start + rx_frame * frame_size);
 148   while ((tph->tp_status & TP_STATUS_USER) && (n_free_bufs > min_bufs))
 149     {
 150       vlib_buffer_t *b0 = 0, *first_b0 = 0;
 151       u32 next0 = next_index;
 152
 153       u32 n_left_to_next;
 154       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 155       while ((tph->tp_status & TP_STATUS_USER) && (n_free_bufs > min_bufs) &&
 156              n_left_to_next)
 157         {
 158
 159           struct virtio_net_hdr *vh =
 160             (struct virtio_net_hdr *) (((u8 *) tph) + tph->tp_mac -
 161                                        sizeof (struct virtio_net_hdr));
 162           u32 data_len = tph->tp_snaplen;
 163           u32 offset = 0;
 164           u32 bi0 = 0, first_bi0 = 0, prev_bi0;
 165           u32 vlan_len = 0;
 166           ip_csum_t wsum = 0;
 167           u16 *wsum_addr = NULL;
 168           u32 do_vnet = apm->flags & AF_PACKET_USES_VNET_HEADERS;
 169           u32 do_csum = tph->tp_status & TP_STATUS_CSUMNOTREADY;
 170
 171           while (data_len)
 172             {
 173               /* grab free buffer */
 174               u32 last_empty_buffer =
 175                 vec_len (apm->rx_buffers[thread_index]) - 1;
 176               prev_bi0 = bi0;
 177               bi0 = apm->rx_buffers[thread_index][last_empty_buffer];
 178               b0 = vlib_get_buffer (vm, bi0);
 179               _vec_len (apm->rx_buffers[thread_index]) = last_empty_buffer;
 180               n_free_bufs--;
 181
 182               /* copy data */
 183               u32 bytes_to_copy =
 184                 data_len > n_buffer_bytes ? n_buffer_bytes : data_len;
 185               u32 bytes_copied = 0;
 186               b0->current_data = 0;
 187               /* Kernel removes VLAN headers, so reconstruct VLAN */
 188               if (PREDICT_FALSE (tph->tp_status & TP_STATUS_VLAN_VALID))
 189                 {
 190                   if (PREDICT_TRUE (offset == 0))
 191                     {
 192                       clib_memcpy (vlib_buffer_get_current (b0),
 193                                    (u8 *) tph + tph->tp_mac,
 194                                    sizeof (ethernet_header_t));
 195                       ethernet_header_t *eth = vlib_buffer_get_current (b0);
 196                       ethernet_vlan_header_t *vlan =
 197                         (ethernet_vlan_header_t *) (eth + 1);
 198                       vlan->priority_cfi_and_id =
 199                         clib_host_to_net_u16 (tph->tp_vlan_tci);
 200                       vlan->type = eth->type;
 201                       eth->type = clib_host_to_net_u16 (ETHERNET_TYPE_VLAN);
 202                       vlan_len = sizeof (ethernet_vlan_header_t);
 203                       bytes_copied = sizeof (ethernet_header_t);
 204                     }
 205                 }
 206               /* Check if the incoming skb is marked as CSUM_PARTIAL,
 207                * If VNET Headers are enabled TP_STATUS_CSUMNOTREADY is
 208                * equivalent to the vnet csum flag.
 209                **/
 210               if (PREDICT_TRUE ((do_vnet != 0) && (do_csum != 0)))
 211                 {
 212                   wsum_addr = (u16 *) (((u8 *) vlib_buffer_get_current (b0)) +
 213                                        vlan_len + vh->csum_start +
 214                                        vh->csum_offset);
 215                   if (bytes_copied <= vh->csum_start)
 216                     {
 217                       clib_memcpy (((u8 *) vlib_buffer_get_current (b0)) +
 218                                    bytes_copied + vlan_len,
 219                                    (u8 *) tph + tph->tp_mac + offset +
 220                                    bytes_copied,
 221                                    (vh->csum_start - bytes_copied));
 222                       wsum =
 223                         ip_csum_and_memcpy (wsum,
 224                                             ((u8 *)
 225                                              vlib_buffer_get_current (b0)) +
 226                                             vh->csum_start + vlan_len,
 227                                             (u8 *) tph + tph->tp_mac +
 228                                             offset + vh->csum_start,
 229                                             (bytes_to_copy - vh->csum_start));
 230                     }
 231                   else
 232                     {
 233                       wsum =
 234                         ip_csum_and_memcpy (wsum,
 235                                             ((u8 *)
 236                                              vlib_buffer_get_current (b0)) +
 237                                             bytes_copied + vlan_len,
 238                                             (u8 *) tph + tph->tp_mac +
 239                                             offset + bytes_copied,
 240                                             (bytes_to_copy - bytes_copied));
 241                     }
 242                 }
 243               else
 244                 {
 245                   clib_memcpy (((u8 *) vlib_buffer_get_current (b0)) +
 246                                bytes_copied + vlan_len,
 247                                (u8 *) tph + tph->tp_mac + offset +
 248                                bytes_copied, (bytes_to_copy - bytes_copied));
 249                 }
 250
 251               /* fill buffer header */
 252               b0->current_length = bytes_to_copy + vlan_len;
 253
 254               if (offset == 0)
 255                 {
 256                   b0->total_length_not_including_first_buffer = 0;
 257                   b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 258                   vnet_buffer (b0)->sw_if_index[VLIB_RX] = apif->sw_if_index;
 259                   vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 260                   first_bi0 = bi0;
 261                   first_b0 = vlib_get_buffer (vm, first_bi0);
 262                 }
 263               else
 264                 buffer_add_to_chain (vm, bi0, first_bi0, prev_bi0);
 265
 266               offset += bytes_to_copy;
 267               data_len -= bytes_to_copy;
 268             }
 269           if (PREDICT_TRUE ((do_vnet != 0) && (do_csum != 0)))
 270             {
 271               *wsum_addr = ~ip_csum_fold (wsum);
 272             }
 273           n_rx_packets++;
 274           n_rx_bytes += tph->tp_snaplen;
 275           to_next[0] = first_bi0;
 276           to_next += 1;
 277           n_left_to_next--;
 278
 279           /* trace */
 280           VLIB_BUFFER_TRACE_TRAJECTORY_INIT (first_b0);
 281           if (PREDICT_FALSE (n_trace > 0))
 282             {
 283               af_packet_input_trace_t *tr;
 284               vlib_trace_buffer (vm, node, next0, first_b0,     /* follow_chain */
 285                                  0);
 286               vlib_set_trace_count (vm, node, --n_trace);
 287               tr = vlib_add_trace (vm, node, first_b0, sizeof (*tr));
 288               tr->next_index = next0;
 289               tr->hw_if_index = apif->hw_if_index;
 290               clib_memcpy (&tr->tph, tph, sizeof (struct tpacket2_hdr));
 291             }
 292
 293           /* redirect if feature path enabled */
 294           vnet_feature_start_device_input_x1 (apif->sw_if_index, &next0, b0);
 295
 296           /* enque and take next packet */
 297           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 298                                            n_left_to_next, first_bi0, next0);
 299
 300           /* next packet */
 301           tph->tp_status = TP_STATUS_KERNEL;
 302           rx_frame = (rx_frame + 1) % frame_num;
 303           tph = (struct tpacket2_hdr *) (block_start + rx_frame * frame_size);
 304         }
 305
 306       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 307     }
 308
 309   apif->next_rx_frame = rx_frame;
 310
 311   vlib_increment_combined_counter
 312     (vnet_get_main ()->interface_main.combined_sw_if_counters
 313      + VNET_INTERFACE_COUNTER_RX,
 314      vlib_get_thread_index (), apif->hw_if_index, n_rx_packets, n_rx_bytes);
 315
 316   vnet_device_increment_rx_packets (thread_index, n_rx_packets);
 317   return n_rx_packets;
 318 }
 319
 320 static uword
 321 af_packet_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 322                     vlib_frame_t * frame)
 323 {
 324   u32 n_rx_packets = 0;
 325   af_packet_main_t *apm = &af_packet_main;
 326   vnet_device_input_runtime_t *rt = (void *) node->runtime_data;
 327   vnet_device_and_queue_t *dq;
 328
 329   foreach_device_and_queue (dq, rt->devices_and_queues)
 330   {
 331     af_packet_if_t *apif;
 332     apif = vec_elt_at_index (apm->interfaces, dq->dev_instance);
 333     if (apif->is_admin_up)
 334       n_rx_packets += af_packet_device_input_fn (vm, node, frame, apif);
 335   }
 336
 337   return n_rx_packets;
 338 }
 339
 340 /* *INDENT-OFF* */
 341 VLIB_REGISTER_NODE (af_packet_input_node) = {
 342   .function = af_packet_input_fn,
 343   .name = "af-packet-input",
 344   .sibling_of = "device-input",
 345   .format_trace = format_af_packet_input_trace,
 346   .type = VLIB_NODE_TYPE_INPUT,
 347   .state = VLIB_NODE_STATE_INTERRUPT,
 348   .n_errors = AF_PACKET_INPUT_N_ERROR,
 349   .error_strings = af_packet_input_error_strings,
 350 };
 351
 352 VLIB_NODE_FUNCTION_MULTIARCH (af_packet_input_node, af_packet_input_fn)
 353 /* *INDENT-ON* */
 354
 355
 356 /*
 357  * fd.io coding-style-patch-verification: ON
 358  *
 359  * Local Variables:
 360  * eval: (c-set-style "gnu")
 361  * End:
 362  */