drivers/net/vsockmon.c

   1 #include <linux/module.h>
   2 #include <linux/kernel.h>
   3 #include <linux/if_arp.h>
   4 #include <net/rtnetlink.h>
   5 #include <net/sock.h>
   6 #include <net/af_vsock.h>
   7 #include <uapi/linux/vsockmon.h>
   8 #include <linux/virtio_vsock.h>
   9
  10 /* Virtio transport max packet size plus header */
  11 #define DEFAULT_MTU (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + \
  12                      sizeof(struct af_vsockmon_hdr))
  13
  14 static int vsockmon_dev_init(struct net_device *dev)
  15 {
  16         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
  17         if (!dev->lstats)
  18                 return -ENOMEM;
  19         return 0;
  20 }
  21
  22 static void vsockmon_dev_uninit(struct net_device *dev)
  23 {
  24         free_percpu(dev->lstats);
  25 }
  26
  27 struct vsockmon {
  28         struct vsock_tap vt;
  29 };
  30
  31 static int vsockmon_open(struct net_device *dev)
  32 {
  33         struct vsockmon *vsockmon = netdev_priv(dev);
  34
  35         vsockmon->vt.dev = dev;
  36         vsockmon->vt.module = THIS_MODULE;
  37         return vsock_add_tap(&vsockmon->vt);
  38 }
  39
  40 static int vsockmon_close(struct net_device *dev)
  41 {
  42         struct vsockmon *vsockmon = netdev_priv(dev);
  43
  44         return vsock_remove_tap(&vsockmon->vt);
  45 }
  46
  47 static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
  48 {
  49         int len = skb->len;
  50         struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);
  51
  52         u64_stats_update_begin(&stats->syncp);
  53         stats->bytes += len;
  54         stats->packets++;
  55         u64_stats_update_end(&stats->syncp);
  56
  57         dev_kfree_skb(skb);
  58
  59         return NETDEV_TX_OK;
  60 }
  61
  62 static void
  63 vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
  64 {
  65         int i;
  66         u64 bytes = 0, packets = 0;
  67
  68         for_each_possible_cpu(i) {
  69                 const struct pcpu_lstats *vstats;
  70                 u64 tbytes, tpackets;
  71                 unsigned int start;
  72
  73                 vstats = per_cpu_ptr(dev->lstats, i);
  74
  75                 do {
  76                         start = u64_stats_fetch_begin_irq(&vstats->syncp);
  77                         tbytes = vstats->bytes;
  78                         tpackets = vstats->packets;
  79                 } while (u64_stats_fetch_retry_irq(&vstats->syncp, start));
  80
  81                 packets += tpackets;
  82                 bytes += tbytes;
  83         }
  84
  85         stats->rx_packets = packets;
  86         stats->tx_packets = 0;
  87
  88         stats->rx_bytes = bytes;
  89         stats->tx_bytes = 0;
  90 }
  91
  92 static int vsockmon_is_valid_mtu(int new_mtu)
  93 {
  94         return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
  95 }
  96
  97 static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
  98 {
  99         if (!vsockmon_is_valid_mtu(new_mtu))
 100                 return -EINVAL;
 101
 102         dev->mtu = new_mtu;
 103         return 0;
 104 }
 105
 106 static const struct net_device_ops vsockmon_ops = {
 107         .ndo_init = vsockmon_dev_init,
 108         .ndo_uninit = vsockmon_dev_uninit,
 109         .ndo_open = vsockmon_open,
 110         .ndo_stop = vsockmon_close,
 111         .ndo_start_xmit = vsockmon_xmit,
 112         .ndo_get_stats64 = vsockmon_get_stats64,
 113         .ndo_change_mtu = vsockmon_change_mtu,
 114 };
 115
 116 static u32 always_on(struct net_device *dev)
 117 {
 118         return 1;
 119 }
 120
 121 static const struct ethtool_ops vsockmon_ethtool_ops = {
 122         .get_link = always_on,
 123 };
 124
 125 static void vsockmon_setup(struct net_device *dev)
 126 {
 127         dev->type = ARPHRD_VSOCKMON;
 128         dev->priv_flags |= IFF_NO_QUEUE;
 129
 130         dev->netdev_ops = &vsockmon_ops;
 131         dev->ethtool_ops = &vsockmon_ethtool_ops;
 132         dev->needs_free_netdev = true;
 133
 134         dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
 135                         NETIF_F_HIGHDMA | NETIF_F_LLTX;
 136
 137         dev->flags = IFF_NOARP;
 138
 139         dev->mtu = DEFAULT_MTU;
 140 }
 141
 142 static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
 143         .kind                   = "vsockmon",
 144         .priv_size              = sizeof(struct vsockmon),
 145         .setup                  = vsockmon_setup,
 146 };
 147
 148 static __init int vsockmon_register(void)
 149 {
 150         return rtnl_link_register(&vsockmon_link_ops);
 151 }
 152
 153 static __exit void vsockmon_unregister(void)
 154 {
 155         rtnl_link_unregister(&vsockmon_link_ops);
 156 }
 157
 158 module_init(vsockmon_register);
 159 module_exit(vsockmon_unregister);
 160
 161 MODULE_LICENSE("GPL v2");
 162 MODULE_AUTHOR("Gerard Garcia <ggarcia@deic.uab.cat>");
 163 MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
 164 MODULE_ALIAS_RTNL_LINK("vsockmon");