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 struct pcpu_lstats {
  15         u64 rx_packets;
  16         u64 rx_bytes;
  17         struct u64_stats_sync syncp;
  18 };
  19
  20 static int vsockmon_dev_init(struct net_device *dev)
  21 {
  22         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
  23         if (!dev->lstats)
  24                 return -ENOMEM;
  25         return 0;
  26 }
  27
  28 static void vsockmon_dev_uninit(struct net_device *dev)
  29 {
  30         free_percpu(dev->lstats);
  31 }
  32
  33 struct vsockmon {
  34         struct vsock_tap vt;
  35 };
  36
  37 static int vsockmon_open(struct net_device *dev)
  38 {
  39         struct vsockmon *vsockmon = netdev_priv(dev);
  40
  41         vsockmon->vt.dev = dev;
  42         vsockmon->vt.module = THIS_MODULE;
  43         return vsock_add_tap(&vsockmon->vt);
  44 }
  45
  46 static int vsockmon_close(struct net_device *dev)
  47 {
  48         struct vsockmon *vsockmon = netdev_priv(dev);
  49
  50         return vsock_remove_tap(&vsockmon->vt);
  51 }
  52
  53 static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
  54 {
  55         int len = skb->len;
  56         struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);
  57
  58         u64_stats_update_begin(&stats->syncp);
  59         stats->rx_bytes += len;
  60         stats->rx_packets++;
  61         u64_stats_update_end(&stats->syncp);
  62
  63         dev_kfree_skb(skb);
  64
  65         return NETDEV_TX_OK;
  66 }
  67
  68 static void
  69 vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
  70 {
  71         int i;
  72         u64 bytes = 0, packets = 0;
  73
  74         for_each_possible_cpu(i) {
  75                 const struct pcpu_lstats *vstats;
  76                 u64 tbytes, tpackets;
  77                 unsigned int start;
  78
  79                 vstats = per_cpu_ptr(dev->lstats, i);
  80
  81                 do {
  82                         start = u64_stats_fetch_begin_irq(&vstats->syncp);
  83                         tbytes = vstats->rx_bytes;
  84                         tpackets = vstats->rx_packets;
  85                 } while (u64_stats_fetch_retry_irq(&vstats->syncp, start));
  86
  87                 packets += tpackets;
  88                 bytes += tbytes;
  89         }
  90
  91         stats->rx_packets = packets;
  92         stats->tx_packets = 0;
  93
  94         stats->rx_bytes = bytes;
  95         stats->tx_bytes = 0;
  96 }
  97
  98 static int vsockmon_is_valid_mtu(int new_mtu)
  99 {
 100         return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
 101 }
 102
 103 static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
 104 {
 105         if (!vsockmon_is_valid_mtu(new_mtu))
 106                 return -EINVAL;
 107
 108         dev->mtu = new_mtu;
 109         return 0;
 110 }
 111
 112 static const struct net_device_ops vsockmon_ops = {
 113         .ndo_init = vsockmon_dev_init,
 114         .ndo_uninit = vsockmon_dev_uninit,
 115         .ndo_open = vsockmon_open,
 116         .ndo_stop = vsockmon_close,
 117         .ndo_start_xmit = vsockmon_xmit,
 118         .ndo_get_stats64 = vsockmon_get_stats64,
 119         .ndo_change_mtu = vsockmon_change_mtu,
 120 };
 121
 122 static u32 always_on(struct net_device *dev)
 123 {
 124         return 1;
 125 }
 126
 127 static const struct ethtool_ops vsockmon_ethtool_ops = {
 128         .get_link = always_on,
 129 };
 130
 131 static void vsockmon_setup(struct net_device *dev)
 132 {
 133         dev->type = ARPHRD_VSOCKMON;
 134         dev->priv_flags |= IFF_NO_QUEUE;
 135
 136         dev->netdev_ops = &vsockmon_ops;
 137         dev->ethtool_ops = &vsockmon_ethtool_ops;
 138         dev->needs_free_netdev = true;
 139
 140         dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
 141                         NETIF_F_HIGHDMA | NETIF_F_LLTX;
 142
 143         dev->flags = IFF_NOARP;
 144
 145         dev->mtu = DEFAULT_MTU;
 146 }
 147
 148 static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
 149         .kind                   = "vsockmon",
 150         .priv_size              = sizeof(struct vsockmon),
 151         .setup                  = vsockmon_setup,
 152 };
 153
 154 static __init int vsockmon_register(void)
 155 {
 156         return rtnl_link_register(&vsockmon_link_ops);
 157 }
 158
 159 static __exit void vsockmon_unregister(void)
 160 {
 161         rtnl_link_unregister(&vsockmon_link_ops);
 162 }
 163
 164 module_init(vsockmon_register);
 165 module_exit(vsockmon_unregister);
 166
 167 MODULE_LICENSE("GPL v2");
 168 MODULE_AUTHOR("Gerard Garcia <ggarcia@deic.uab.cat>");
 169 MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
 170 MODULE_ALIAS_RTNL_LINK("vsockmon");