1e4fc408eSDaniel Borkmann #include <linux/module.h> 2e4fc408eSDaniel Borkmann #include <linux/kernel.h> 3e4fc408eSDaniel Borkmann #include <linux/netdevice.h> 4e4fc408eSDaniel Borkmann #include <linux/netlink.h> 5e4fc408eSDaniel Borkmann #include <net/net_namespace.h> 6e4fc408eSDaniel Borkmann #include <linux/if_arp.h> 7e4fc408eSDaniel Borkmann 8e4fc408eSDaniel Borkmann struct pcpu_lstats { 9e4fc408eSDaniel Borkmann u64 packets; 10e4fc408eSDaniel Borkmann u64 bytes; 11e4fc408eSDaniel Borkmann struct u64_stats_sync syncp; 12e4fc408eSDaniel Borkmann }; 13e4fc408eSDaniel Borkmann 14e4fc408eSDaniel Borkmann static netdev_tx_t nlmon_xmit(struct sk_buff *skb, struct net_device *dev) 15e4fc408eSDaniel Borkmann { 16e4fc408eSDaniel Borkmann int len = skb->len; 17e4fc408eSDaniel Borkmann struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats); 18e4fc408eSDaniel Borkmann 19e4fc408eSDaniel Borkmann u64_stats_update_begin(&stats->syncp); 20e4fc408eSDaniel Borkmann stats->bytes += len; 21e4fc408eSDaniel Borkmann stats->packets++; 22e4fc408eSDaniel Borkmann u64_stats_update_end(&stats->syncp); 23e4fc408eSDaniel Borkmann 24e4fc408eSDaniel Borkmann dev_kfree_skb(skb); 25e4fc408eSDaniel Borkmann 26e4fc408eSDaniel Borkmann return NETDEV_TX_OK; 27e4fc408eSDaniel Borkmann } 28e4fc408eSDaniel Borkmann 29e4fc408eSDaniel Borkmann static int nlmon_is_valid_mtu(int new_mtu) 30e4fc408eSDaniel Borkmann { 31e4fc408eSDaniel Borkmann return new_mtu >= sizeof(struct nlmsghdr) && new_mtu <= INT_MAX; 32e4fc408eSDaniel Borkmann } 33e4fc408eSDaniel Borkmann 34e4fc408eSDaniel Borkmann static int nlmon_change_mtu(struct net_device *dev, int new_mtu) 35e4fc408eSDaniel Borkmann { 36e4fc408eSDaniel Borkmann if (!nlmon_is_valid_mtu(new_mtu)) 37e4fc408eSDaniel Borkmann return -EINVAL; 38e4fc408eSDaniel Borkmann 39e4fc408eSDaniel Borkmann dev->mtu = new_mtu; 40e4fc408eSDaniel Borkmann return 0; 41e4fc408eSDaniel Borkmann } 42e4fc408eSDaniel Borkmann 43e4fc408eSDaniel Borkmann static int nlmon_dev_init(struct net_device *dev) 44e4fc408eSDaniel Borkmann { 45e4fc408eSDaniel Borkmann dev->lstats = alloc_percpu(struct pcpu_lstats); 46e4fc408eSDaniel Borkmann 47e4fc408eSDaniel Borkmann return dev->lstats == NULL ? -ENOMEM : 0; 48e4fc408eSDaniel Borkmann } 49e4fc408eSDaniel Borkmann 50e4fc408eSDaniel Borkmann static void nlmon_dev_uninit(struct net_device *dev) 51e4fc408eSDaniel Borkmann { 52e4fc408eSDaniel Borkmann free_percpu(dev->lstats); 53e4fc408eSDaniel Borkmann } 54e4fc408eSDaniel Borkmann 55e4fc408eSDaniel Borkmann static struct netlink_tap nlmon_tap; 56e4fc408eSDaniel Borkmann 57e4fc408eSDaniel Borkmann static int nlmon_open(struct net_device *dev) 58e4fc408eSDaniel Borkmann { 59e4fc408eSDaniel Borkmann return netlink_add_tap(&nlmon_tap); 60e4fc408eSDaniel Borkmann } 61e4fc408eSDaniel Borkmann 62e4fc408eSDaniel Borkmann static int nlmon_close(struct net_device *dev) 63e4fc408eSDaniel Borkmann { 64e4fc408eSDaniel Borkmann return netlink_remove_tap(&nlmon_tap); 65e4fc408eSDaniel Borkmann } 66e4fc408eSDaniel Borkmann 67e4fc408eSDaniel Borkmann static struct rtnl_link_stats64 * 68e4fc408eSDaniel Borkmann nlmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) 69e4fc408eSDaniel Borkmann { 70e4fc408eSDaniel Borkmann int i; 71e4fc408eSDaniel Borkmann u64 bytes = 0, packets = 0; 72e4fc408eSDaniel Borkmann 73e4fc408eSDaniel Borkmann for_each_possible_cpu(i) { 74e4fc408eSDaniel Borkmann const struct pcpu_lstats *nl_stats; 75e4fc408eSDaniel Borkmann u64 tbytes, tpackets; 76e4fc408eSDaniel Borkmann unsigned int start; 77e4fc408eSDaniel Borkmann 78e4fc408eSDaniel Borkmann nl_stats = per_cpu_ptr(dev->lstats, i); 79e4fc408eSDaniel Borkmann 80e4fc408eSDaniel Borkmann do { 81e4fc408eSDaniel Borkmann start = u64_stats_fetch_begin_bh(&nl_stats->syncp); 82e4fc408eSDaniel Borkmann tbytes = nl_stats->bytes; 83e4fc408eSDaniel Borkmann tpackets = nl_stats->packets; 84e4fc408eSDaniel Borkmann } while (u64_stats_fetch_retry_bh(&nl_stats->syncp, start)); 85e4fc408eSDaniel Borkmann 86e4fc408eSDaniel Borkmann packets += tpackets; 87e4fc408eSDaniel Borkmann bytes += tbytes; 88e4fc408eSDaniel Borkmann } 89e4fc408eSDaniel Borkmann 90e4fc408eSDaniel Borkmann stats->rx_packets = packets; 91e4fc408eSDaniel Borkmann stats->tx_packets = 0; 92e4fc408eSDaniel Borkmann 93e4fc408eSDaniel Borkmann stats->rx_bytes = bytes; 94e4fc408eSDaniel Borkmann stats->tx_bytes = 0; 95e4fc408eSDaniel Borkmann 96e4fc408eSDaniel Borkmann return stats; 97e4fc408eSDaniel Borkmann } 98e4fc408eSDaniel Borkmann 99e4fc408eSDaniel Borkmann static u32 always_on(struct net_device *dev) 100e4fc408eSDaniel Borkmann { 101e4fc408eSDaniel Borkmann return 1; 102e4fc408eSDaniel Borkmann } 103e4fc408eSDaniel Borkmann 104e4fc408eSDaniel Borkmann static const struct ethtool_ops nlmon_ethtool_ops = { 105e4fc408eSDaniel Borkmann .get_link = always_on, 106e4fc408eSDaniel Borkmann }; 107e4fc408eSDaniel Borkmann 108e4fc408eSDaniel Borkmann static const struct net_device_ops nlmon_ops = { 109e4fc408eSDaniel Borkmann .ndo_init = nlmon_dev_init, 110e4fc408eSDaniel Borkmann .ndo_uninit = nlmon_dev_uninit, 111e4fc408eSDaniel Borkmann .ndo_open = nlmon_open, 112e4fc408eSDaniel Borkmann .ndo_stop = nlmon_close, 113e4fc408eSDaniel Borkmann .ndo_start_xmit = nlmon_xmit, 114e4fc408eSDaniel Borkmann .ndo_get_stats64 = nlmon_get_stats64, 115e4fc408eSDaniel Borkmann .ndo_change_mtu = nlmon_change_mtu, 116e4fc408eSDaniel Borkmann }; 117e4fc408eSDaniel Borkmann 118e4fc408eSDaniel Borkmann static struct netlink_tap nlmon_tap __read_mostly = { 119e4fc408eSDaniel Borkmann .module = THIS_MODULE, 120e4fc408eSDaniel Borkmann }; 121e4fc408eSDaniel Borkmann 122e4fc408eSDaniel Borkmann static void nlmon_setup(struct net_device *dev) 123e4fc408eSDaniel Borkmann { 124e4fc408eSDaniel Borkmann dev->type = ARPHRD_NETLINK; 125e4fc408eSDaniel Borkmann dev->tx_queue_len = 0; 126e4fc408eSDaniel Borkmann 127e4fc408eSDaniel Borkmann dev->netdev_ops = &nlmon_ops; 128e4fc408eSDaniel Borkmann dev->ethtool_ops = &nlmon_ethtool_ops; 129e4fc408eSDaniel Borkmann dev->destructor = free_netdev; 130e4fc408eSDaniel Borkmann 131e4fc408eSDaniel Borkmann dev->features = NETIF_F_FRAGLIST | NETIF_F_HIGHDMA; 132e4fc408eSDaniel Borkmann dev->flags = IFF_NOARP; 133e4fc408eSDaniel Borkmann 134e4fc408eSDaniel Borkmann /* That's rather a softlimit here, which, of course, 135e4fc408eSDaniel Borkmann * can be altered. Not a real MTU, but what is to be 136e4fc408eSDaniel Borkmann * expected in most cases. 137e4fc408eSDaniel Borkmann */ 138e4fc408eSDaniel Borkmann dev->mtu = NLMSG_GOODSIZE; 139e4fc408eSDaniel Borkmann } 140e4fc408eSDaniel Borkmann 141e4fc408eSDaniel Borkmann static __init int nlmon_register(void) 142e4fc408eSDaniel Borkmann { 143e4fc408eSDaniel Borkmann int err; 144e4fc408eSDaniel Borkmann struct net_device *nldev; 145e4fc408eSDaniel Borkmann 146e4fc408eSDaniel Borkmann nldev = nlmon_tap.dev = alloc_netdev(0, "netlink", nlmon_setup); 147e4fc408eSDaniel Borkmann if (unlikely(nldev == NULL)) 148e4fc408eSDaniel Borkmann return -ENOMEM; 149e4fc408eSDaniel Borkmann 150e4fc408eSDaniel Borkmann err = register_netdev(nldev); 151e4fc408eSDaniel Borkmann if (unlikely(err)) 152e4fc408eSDaniel Borkmann free_netdev(nldev); 153e4fc408eSDaniel Borkmann 154e4fc408eSDaniel Borkmann return err; 155e4fc408eSDaniel Borkmann } 156e4fc408eSDaniel Borkmann 157e4fc408eSDaniel Borkmann static __exit void nlmon_unregister(void) 158e4fc408eSDaniel Borkmann { 159e4fc408eSDaniel Borkmann struct net_device *nldev = nlmon_tap.dev; 160e4fc408eSDaniel Borkmann 161e4fc408eSDaniel Borkmann unregister_netdev(nldev); 162e4fc408eSDaniel Borkmann } 163e4fc408eSDaniel Borkmann 164e4fc408eSDaniel Borkmann module_init(nlmon_register); 165e4fc408eSDaniel Borkmann module_exit(nlmon_unregister); 166e4fc408eSDaniel Borkmann 167e4fc408eSDaniel Borkmann MODULE_LICENSE("GPL v2"); 168e4fc408eSDaniel Borkmann MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>"); 169e4fc408eSDaniel Borkmann MODULE_AUTHOR("Mathieu Geli <geli@enseirb.fr>"); 170e4fc408eSDaniel Borkmann MODULE_DESCRIPTION("Netlink monitoring device"); 171