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 struct vsockmon {
  17         struct vsock_tap vt;
  18 };
  19
  20 static int vsockmon_open(struct net_device *dev)
  21 {
  22         struct vsockmon *vsockmon = netdev_priv(dev);
  23
  24         vsockmon->vt.dev = dev;
  25         vsockmon->vt.module = THIS_MODULE;
  26         return vsock_add_tap(&vsockmon->vt);
  27 }
  28
  29 static int vsockmon_close(struct net_device *dev)
  30 {
  31         struct vsockmon *vsockmon = netdev_priv(dev);
  32
  33         return vsock_remove_tap(&vsockmon->vt);
  34 }
  35
  36 static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
  37 {
  38         dev_lstats_add(dev, skb->len);
  39
  40         dev_kfree_skb(skb);
  41
  42         return NETDEV_TX_OK;
  43 }
  44
  45 static void
  46 vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
  47 {
  48         dev_lstats_read(dev, &stats->rx_packets, &stats->rx_bytes);
  49 }
  50
  51 static int vsockmon_is_valid_mtu(int new_mtu)
  52 {
  53         return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
  54 }
  55
  56 static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
  57 {
  58         if (!vsockmon_is_valid_mtu(new_mtu))
  59                 return -EINVAL;
  60
  61         WRITE_ONCE(dev->mtu, new_mtu);
  62         return 0;
  63 }
  64
  65 static const struct net_device_ops vsockmon_ops = {
  66         .ndo_open = vsockmon_open,
  67         .ndo_stop = vsockmon_close,
  68         .ndo_start_xmit = vsockmon_xmit,
  69         .ndo_get_stats64 = vsockmon_get_stats64,
  70         .ndo_change_mtu = vsockmon_change_mtu,
  71 };
  72
  73 static u32 always_on(struct net_device *dev)
  74 {
  75         return 1;
  76 }
  77
  78 static const struct ethtool_ops vsockmon_ethtool_ops = {
  79         .get_link = always_on,
  80 };
  81
  82 static void vsockmon_setup(struct net_device *dev)
  83 {
  84         dev->type = ARPHRD_VSOCKMON;
  85         dev->priv_flags |= IFF_NO_QUEUE;
  86         dev->lltx = true;
  87
  88         dev->netdev_ops = &vsockmon_ops;
  89         dev->ethtool_ops = &vsockmon_ethtool_ops;
  90         dev->needs_free_netdev = true;
  91
  92         dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA;
  93
  94         dev->flags = IFF_NOARP;
  95
  96         dev->mtu = DEFAULT_MTU;
  97         dev->pcpu_stat_type = NETDEV_PCPU_STAT_LSTATS;
  98 }
  99
 100 static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
 101         .kind                   = "vsockmon",
 102         .priv_size              = sizeof(struct vsockmon),
 103         .setup                  = vsockmon_setup,
 104 };
 105
 106 static __init int vsockmon_register(void)
 107 {
 108         return rtnl_link_register(&vsockmon_link_ops);
 109 }
 110
 111 static __exit void vsockmon_unregister(void)
 112 {
 113         rtnl_link_unregister(&vsockmon_link_ops);
 114 }
 115
 116 module_init(vsockmon_register);
 117 module_exit(vsockmon_unregister);
 118
 119 MODULE_LICENSE("GPL v2");
 120 MODULE_AUTHOR("Gerard Garcia <ggarcia@deic.uab.cat>");
 121 MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
 122 MODULE_ALIAS_RTNL_LINK("vsockmon");