af_packet.c

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/*
 *------------------------------------------------------------------
 * af_packet.c - linux kernel packet interface
 *
 * Copyright (c) 2016 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *------------------------------------------------------------------
 */

#include <linux/if_ether.h>
#include <linux/if_packet.h>

#include <vlib/vlib.h>
#include <vlib/unix/unix.h>
#include <vnet/ip/ip.h>
#include <vnet/ethernet/ethernet.h>

#include <vnet/devices/af_packet/af_packet.h>

#define AF_PACKET_DEBUG_SOCKET          0

#define AF_PACKET_TX_FRAMES_PER_BLOCK   1024
#define AF_PACKET_TX_FRAME_SIZE         (2048 * 5)
#define AF_PACKET_TX_BLOCK_NR           1
#define AF_PACKET_TX_FRAME_NR           (AF_PACKET_TX_BLOCK_NR * \
                                         AF_PACKET_TX_FRAMES_PER_BLOCK)
#define AF_PACKET_TX_BLOCK_SIZE         (AF_PACKET_TX_FRAME_SIZE * \
                                         AF_PACKET_TX_FRAMES_PER_BLOCK)

#define AF_PACKET_RX_FRAMES_PER_BLOCK   1024
#define AF_PACKET_RX_FRAME_SIZE         (2048 * 5)
#define AF_PACKET_RX_BLOCK_NR           1
#define AF_PACKET_RX_FRAME_NR           (AF_PACKET_RX_BLOCK_NR * \
                                         AF_PACKET_RX_FRAMES_PER_BLOCK)
#define AF_PACKET_RX_BLOCK_SIZE         (AF_PACKET_RX_FRAME_SIZE * \
                                         AF_PACKET_RX_FRAMES_PER_BLOCK)

#if AF_PACKET_DEBUG_SOCKET == 1
#define DBG_SOCK(args...) clib_warning(args);
#else
#define DBG_SOCK(args...)
#endif

/*defined in net/if.h but clashes with dpdk headers */
unsigned int if_nametoindex(const char *ifname);

typedef struct tpacket_req tpacket_req_t;

static u32
af_packet_eth_flag_change (vnet_main_t * vnm, vnet_hw_interface_t * hi, u32 flags)
{
  /* nothing for now */
  return 0;
}

static clib_error_t * af_packet_fd_read_ready (unix_file_t * uf)
{
  vlib_main_t * vm = vlib_get_main();
  af_packet_main_t * apm = &af_packet_main;
  u32 idx = uf->private_data;

  apm->pending_input_bitmap = clib_bitmap_set (apm->pending_input_bitmap, idx, 1);

  /* Schedule the rx node */
  vlib_node_set_interrupt_pending (vm, af_packet_input_node.index);

  return 0;
}

static int
create_packet_v2_sock(u8 * name, tpacket_req_t * rx_req, tpacket_req_t * tx_req,
                      int *fd, u8 ** ring)
{
  int ret, err;
  struct sockaddr_ll sll;
  uint host_if_index;
  int ver = TPACKET_V2;
  socklen_t req_sz = sizeof(struct tpacket_req);
  u32 ring_sz = rx_req->tp_block_size * rx_req->tp_block_nr +
                tx_req->tp_block_size * tx_req->tp_block_nr;

  host_if_index = if_nametoindex((const char *) name);

  if (!host_if_index)
    {
      DBG_SOCK("Wrong host interface name");
      ret = VNET_API_ERROR_INVALID_INTERFACE;
      goto error;
    }

  if ((*fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL))) < 0)
    {
      DBG_SOCK("Failed to create socket");
      ret = VNET_API_ERROR_SYSCALL_ERROR_1;
      goto error;
    }

  if ((err = setsockopt(*fd, SOL_PACKET, PACKET_VERSION, &ver, sizeof(ver))) < 0)
    {
      DBG_SOCK("Failed to set rx packet interface version");
      ret = VNET_API_ERROR_SYSCALL_ERROR_1;
      goto error;
    }

  int opt = 1;
  if ((err = setsockopt(*fd, SOL_PACKET, PACKET_LOSS, &opt, sizeof(opt))) < 0)
    {
      DBG_SOCK("Failed to set rx packet interface version");
      ret = VNET_API_ERROR_SYSCALL_ERROR_1;
      goto error;
    }

  if ((err = setsockopt(*fd, SOL_PACKET, PACKET_RX_RING, rx_req, req_sz)) < 0)
    {
      DBG_SOCK("Failed to set packet rx ring options");
      ret = VNET_API_ERROR_SYSCALL_ERROR_1;
      goto error;
    }

  if ((err = setsockopt(*fd, SOL_PACKET, PACKET_TX_RING, tx_req, req_sz)) < 0)
    {
      DBG_SOCK("Failed to set packet rx ring options");
      ret = VNET_API_ERROR_SYSCALL_ERROR_1;
      goto error;
    }

  *ring = mmap(NULL, ring_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_LOCKED, *fd, 0);
  if (*ring == MAP_FAILED)
    {
      DBG_SOCK("mmap failure");
      ret = VNET_API_ERROR_SYSCALL_ERROR_1;
      goto error;
    }

  memset(&sll, 0, sizeof(sll));
  sll.sll_family = PF_PACKET;
  sll.sll_protocol = htons(ETH_P_ALL);
  sll.sll_ifindex = host_if_index;

  if ((err = bind(*fd, (struct sockaddr *) &sll, sizeof(sll))) < 0)
    {
      DBG_SOCK("Failed to bind rx packet socket (error %d)", err);
      ret = VNET_API_ERROR_SYSCALL_ERROR_1;
      goto error;
    }

  return 0;
error:
  close(*fd);
  *fd = -1;
  return ret;
}

int
af_packet_create_if(vlib_main_t * vm, u8 * host_if_name, u8 * hw_addr_set)
{
  af_packet_main_t * apm = &af_packet_main;
  int ret, fd = -1;
  struct tpacket_req * rx_req = 0;
  struct tpacket_req * tx_req = 0;
  u8 * ring = 0;
  af_packet_if_t * apif = 0;
  u8 hw_addr[6];
  clib_error_t * error;
  vnet_sw_interface_t * sw;
  vnet_main_t *vnm = vnet_get_main();
  uword * p;
  uword if_index;

  p = mhash_get (&apm->if_index_by_host_if_name, host_if_name);
  if (p)
    {
      return VNET_API_ERROR_SUBIF_ALREADY_EXISTS;
    }

  vec_validate(rx_req, 0);
  rx_req->tp_block_size = AF_PACKET_RX_BLOCK_SIZE;
  rx_req->tp_frame_size = AF_PACKET_RX_FRAME_SIZE;
  rx_req->tp_block_nr = AF_PACKET_RX_BLOCK_NR;
  rx_req->tp_frame_nr = AF_PACKET_RX_FRAME_NR;

  vec_validate(tx_req, 0);
  tx_req->tp_block_size = AF_PACKET_TX_BLOCK_SIZE;
  tx_req->tp_frame_size = AF_PACKET_TX_FRAME_SIZE;
  tx_req->tp_block_nr = AF_PACKET_TX_BLOCK_NR;
  tx_req->tp_frame_nr = AF_PACKET_TX_FRAME_NR;

  ret = create_packet_v2_sock(host_if_name, rx_req, tx_req, &fd, &ring);

  if (ret != 0)
    goto error;

  /* So far everything looks good, let's create interface */
  pool_get (apm->interfaces, apif);
  if_index = apif - apm->interfaces;

  apif->fd = fd;
  apif->rx_ring = ring;
  apif->tx_ring = ring + rx_req->tp_block_size * rx_req->tp_block_nr;
  apif->rx_req = rx_req;
  apif->tx_req = tx_req;
  apif->host_if_name = host_if_name;
  apif->per_interface_next_index = ~0;
  apif->next_tx_frame = 0;
  apif->next_rx_frame = 0;

  {
    unix_file_t template = {0};
    template.read_function = af_packet_fd_read_ready;
    template.file_descriptor = fd;
    template.private_data = if_index;
    template.flags = UNIX_FILE_EVENT_EDGE_TRIGGERED;
    apif->unix_file_index = unix_file_add (&unix_main, &template);
  }

  /*use configured or generate random MAC address */
  if (hw_addr_set)
    clib_memcpy(hw_addr, hw_addr_set, 6);
  else
    {
      f64 now = vlib_time_now(vm);
      u32 rnd;
      rnd = (u32) (now * 1e6);
      rnd = random_u32 (&rnd);

      clib_memcpy (hw_addr+2, &rnd, sizeof(rnd));
      hw_addr[0] = 2;
      hw_addr[1] = 0xfe;
    }

  error = ethernet_register_interface(vnm, af_packet_device_class.index,
                                      if_index, hw_addr, &apif->hw_if_index,
                                      af_packet_eth_flag_change);

  if (error)
    {
      memset(apif, 0, sizeof(*apif));
      pool_put(apm->interfaces, apif);
      clib_error_report (error);
      ret = VNET_API_ERROR_SYSCALL_ERROR_1;
      goto error;
    }

  sw = vnet_get_hw_sw_interface (vnm, apif->hw_if_index);
  apif->sw_if_index = sw->sw_if_index;

  vnet_hw_interface_set_flags (vnm, apif->hw_if_index,
                               VNET_HW_INTERFACE_FLAG_LINK_UP);

  mhash_set_mem (&apm->if_index_by_host_if_name, host_if_name, &if_index, 0);

  return 0;

error:
  vec_free(host_if_name);
  vec_free(rx_req);
  vec_free(tx_req);
  return ret;
}

int
af_packet_delete_if(vlib_main_t *vm, u8 *host_if_name)
{
  vnet_main_t *vnm = vnet_get_main();
  af_packet_main_t *apm = &af_packet_main;
  af_packet_if_t *apif;
  uword *p;
  uword if_index;
  u32 ring_sz;

  p = mhash_get(&apm->if_index_by_host_if_name, host_if_name);
  if (p == NULL) {
    clib_warning("Host interface %s does not exist", host_if_name);
    return VNET_API_ERROR_SYSCALL_ERROR_1;
  }
  apif = pool_elt_at_index(apm->interfaces, p[0]);
  if_index = apif - apm->interfaces;

  /* bring down the interface */
  vnet_hw_interface_set_flags(vnm, apif->hw_if_index, 0);

  /* clean up */
  if (apif->unix_file_index != ~0) {
    unix_file_del(&unix_main, unix_main.file_pool + apif->unix_file_index);
    apif->unix_file_index = ~0;
  }
  ring_sz = apif->rx_req->tp_block_size * apif->rx_req->tp_block_nr +
            apif->tx_req->tp_block_size * apif->tx_req->tp_block_nr;
  if (munmap(apif->rx_ring, ring_sz))
    clib_warning("Host interface %s could not free rx/tx ring", host_if_name);
  apif->rx_ring = NULL;
  apif->tx_ring = NULL;
  close(apif->fd);
  apif->fd = -1;

  vec_free(apif->rx_req);
  apif->rx_req = NULL;
  vec_free(apif->tx_req);
  apif->tx_req = NULL;

  vec_free(apif->host_if_name);
  apif->host_if_name = NULL;

  mhash_unset(&apm->if_index_by_host_if_name, host_if_name, &if_index);

  ethernet_delete_interface(vnm, apif->hw_if_index);

  pool_put(apm->interfaces, apif);

  return 0;
}

static clib_error_t *
af_packet_init (vlib_main_t * vm)
{
  af_packet_main_t * apm = &af_packet_main;

  memset (apm, 0, sizeof (af_packet_main_t));

  mhash_init_vec_string (&apm->if_index_by_host_if_name, sizeof (uword));

  return 0;
}

VLIB_INIT_FUNCTION (af_packet_init);