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