drivers/net/vsockmon.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/module.h>
   3 #include <linux/kernel.h>
   4 #include <linux/if_arp.h>
   5 #include <net/rtnetlink.h>
   6 #include <net/sock.h>
   7 #include <net/af_vsock.h>
   8 #include <uapi/linux/vsockmon.h>
   9 #include <linux/virtio_vsock.h>
  10
  11 /* Virtio transport max packet size plus header */
  12 #define DEFAULT_MTU (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + \
  13                      sizeof(struct af_vsockmon_hdr))
  14
  15 static int vsockmon_dev_init(struct net_device *dev)
  16 {
  17         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
  18         if (!dev->lstats)
  19                 return -ENOMEM;
  20         return 0;
  21 }
  22
  23 static void vsockmon_dev_uninit(struct net_device *dev)
  24 {
  25         free_percpu(dev->lstats);
  26 }
  27
  28 struct vsockmon {
  29         struct vsock_tap vt;
  30 };
  31
  32 static int vsockmon_open(struct net_device *dev)
  33 {
  34         struct vsockmon *vsockmon = netdev_priv(dev);
  35
  36         vsockmon->vt.dev = dev;
  37         vsockmon->vt.module = THIS_MODULE;
  38         return vsock_add_tap(&vsockmon->vt);
  39 }
  40
  41 static int vsockmon_close(struct net_device *dev)
  42 {
  43         struct vsockmon *vsockmon = netdev_priv(dev);
  44
  45         return vsock_remove_tap(&vsockmon->vt);
  46 }
  47
  48 static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
  49 {
  50         dev_lstats_add(dev, skb->len);
  51
  52         dev_kfree_skb(skb);
  53
  54         return NETDEV_TX_OK;
  55 }
  56
  57 static void
  58 vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
  59 {
  60         dev_lstats_read(dev, &stats->rx_packets, &stats->rx_bytes);
  61
  62         stats->tx_packets = 0;
  63         stats->tx_bytes = 0;
  64 }
  65
  66 static int vsockmon_is_valid_mtu(int new_mtu)
  67 {
  68         return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
  69 }
  70
  71 static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
  72 {
  73         if (!vsockmon_is_valid_mtu(new_mtu))
  74                 return -EINVAL;
  75
  76         dev->mtu = new_mtu;
  77         return 0;
  78 }
  79
  80 static const struct net_device_ops vsockmon_ops = {
  81         .ndo_init = vsockmon_dev_init,
  82         .ndo_uninit = vsockmon_dev_uninit,
  83         .ndo_open = vsockmon_open,
  84         .ndo_stop = vsockmon_close,
  85         .ndo_start_xmit = vsockmon_xmit,
  86         .ndo_get_stats64 = vsockmon_get_stats64,
  87         .ndo_change_mtu = vsockmon_change_mtu,
  88 };
  89
  90 static u32 always_on(struct net_device *dev)
  91 {
  92         return 1;
  93 }
  94
  95 static const struct ethtool_ops vsockmon_ethtool_ops = {
  96         .get_link = always_on,
  97 };
  98
  99 static void vsockmon_setup(struct net_device *dev)
 100 {
 101         dev->type = ARPHRD_VSOCKMON;
 102         dev->priv_flags |= IFF_NO_QUEUE;
 103
 104         dev->netdev_ops = &vsockmon_ops;
 105         dev->ethtool_ops = &vsockmon_ethtool_ops;
 106         dev->needs_free_netdev = true;
 107
 108         dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
 109                         NETIF_F_HIGHDMA | NETIF_F_LLTX;
 110
 111         dev->flags = IFF_NOARP;
 112
 113         dev->mtu = DEFAULT_MTU;
 114 }
 115
 116 static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
 117         .kind                   = "vsockmon",
 118         .priv_size              = sizeof(struct vsockmon),
 119         .setup                  = vsockmon_setup,
 120 };
 121
 122 static __init int vsockmon_register(void)
 123 {
 124         return rtnl_link_register(&vsockmon_link_ops);
 125 }
 126
 127 static __exit void vsockmon_unregister(void)
 128 {
 129         rtnl_link_unregister(&vsockmon_link_ops);
 130 }
 131
 132 module_init(vsockmon_register);
 133 module_exit(vsockmon_unregister);
 134
 135 MODULE_LICENSE("GPL v2");
 136 MODULE_AUTHOR("Gerard Garcia <ggarcia@deic.uab.cat>");
 137 MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
 138 MODULE_ALIAS_RTNL_LINK("vsockmon");