drivers/net/vsockmon.c

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