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"); 166