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