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 { 313b233fe0SDaniel Borkmann /* Note that in netlink we do not really have an upper limit. On 323b233fe0SDaniel Borkmann * default, we use NLMSG_GOODSIZE. Here at least we should make 333b233fe0SDaniel Borkmann * sure that it's at least the header size. 343b233fe0SDaniel Borkmann */ 353b233fe0SDaniel Borkmann return new_mtu >= (int) sizeof(struct nlmsghdr); 36e4fc408eSDaniel Borkmann } 37e4fc408eSDaniel Borkmann 38e4fc408eSDaniel Borkmann static int nlmon_change_mtu(struct net_device *dev, int new_mtu) 39e4fc408eSDaniel Borkmann { 40e4fc408eSDaniel Borkmann if (!nlmon_is_valid_mtu(new_mtu)) 41e4fc408eSDaniel Borkmann return -EINVAL; 42e4fc408eSDaniel Borkmann 43e4fc408eSDaniel Borkmann dev->mtu = new_mtu; 44e4fc408eSDaniel Borkmann return 0; 45e4fc408eSDaniel Borkmann } 46e4fc408eSDaniel Borkmann 47e4fc408eSDaniel Borkmann static int nlmon_dev_init(struct net_device *dev) 48e4fc408eSDaniel Borkmann { 49e4fc408eSDaniel Borkmann dev->lstats = alloc_percpu(struct pcpu_lstats); 50e4fc408eSDaniel Borkmann 51e4fc408eSDaniel Borkmann return dev->lstats == NULL ? -ENOMEM : 0; 52e4fc408eSDaniel Borkmann } 53e4fc408eSDaniel Borkmann 54e4fc408eSDaniel Borkmann static void nlmon_dev_uninit(struct net_device *dev) 55e4fc408eSDaniel Borkmann { 56e4fc408eSDaniel Borkmann free_percpu(dev->lstats); 57e4fc408eSDaniel Borkmann } 58e4fc408eSDaniel Borkmann 59e4fc408eSDaniel Borkmann static struct netlink_tap nlmon_tap; 60e4fc408eSDaniel Borkmann 61e4fc408eSDaniel Borkmann static int nlmon_open(struct net_device *dev) 62e4fc408eSDaniel Borkmann { 63e4fc408eSDaniel Borkmann return netlink_add_tap(&nlmon_tap); 64e4fc408eSDaniel Borkmann } 65e4fc408eSDaniel Borkmann 66e4fc408eSDaniel Borkmann static int nlmon_close(struct net_device *dev) 67e4fc408eSDaniel Borkmann { 68e4fc408eSDaniel Borkmann return netlink_remove_tap(&nlmon_tap); 69e4fc408eSDaniel Borkmann } 70e4fc408eSDaniel Borkmann 71e4fc408eSDaniel Borkmann static struct rtnl_link_stats64 * 72e4fc408eSDaniel Borkmann nlmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) 73e4fc408eSDaniel Borkmann { 74e4fc408eSDaniel Borkmann int i; 75e4fc408eSDaniel Borkmann u64 bytes = 0, packets = 0; 76e4fc408eSDaniel Borkmann 77e4fc408eSDaniel Borkmann for_each_possible_cpu(i) { 78e4fc408eSDaniel Borkmann const struct pcpu_lstats *nl_stats; 79e4fc408eSDaniel Borkmann u64 tbytes, tpackets; 80e4fc408eSDaniel Borkmann unsigned int start; 81e4fc408eSDaniel Borkmann 82e4fc408eSDaniel Borkmann nl_stats = per_cpu_ptr(dev->lstats, i); 83e4fc408eSDaniel Borkmann 84e4fc408eSDaniel Borkmann do { 85e4fc408eSDaniel Borkmann start = u64_stats_fetch_begin_bh(&nl_stats->syncp); 86e4fc408eSDaniel Borkmann tbytes = nl_stats->bytes; 87e4fc408eSDaniel Borkmann tpackets = nl_stats->packets; 88e4fc408eSDaniel Borkmann } while (u64_stats_fetch_retry_bh(&nl_stats->syncp, start)); 89e4fc408eSDaniel Borkmann 90e4fc408eSDaniel Borkmann packets += tpackets; 91e4fc408eSDaniel Borkmann bytes += tbytes; 92e4fc408eSDaniel Borkmann } 93e4fc408eSDaniel Borkmann 94e4fc408eSDaniel Borkmann stats->rx_packets = packets; 95e4fc408eSDaniel Borkmann stats->tx_packets = 0; 96e4fc408eSDaniel Borkmann 97e4fc408eSDaniel Borkmann stats->rx_bytes = bytes; 98e4fc408eSDaniel Borkmann stats->tx_bytes = 0; 99e4fc408eSDaniel Borkmann 100e4fc408eSDaniel Borkmann return stats; 101e4fc408eSDaniel Borkmann } 102e4fc408eSDaniel Borkmann 103e4fc408eSDaniel Borkmann static u32 always_on(struct net_device *dev) 104e4fc408eSDaniel Borkmann { 105e4fc408eSDaniel Borkmann return 1; 106e4fc408eSDaniel Borkmann } 107e4fc408eSDaniel Borkmann 108e4fc408eSDaniel Borkmann static const struct ethtool_ops nlmon_ethtool_ops = { 109e4fc408eSDaniel Borkmann .get_link = always_on, 110e4fc408eSDaniel Borkmann }; 111e4fc408eSDaniel Borkmann 112e4fc408eSDaniel Borkmann static const struct net_device_ops nlmon_ops = { 113e4fc408eSDaniel Borkmann .ndo_init = nlmon_dev_init, 114e4fc408eSDaniel Borkmann .ndo_uninit = nlmon_dev_uninit, 115e4fc408eSDaniel Borkmann .ndo_open = nlmon_open, 116e4fc408eSDaniel Borkmann .ndo_stop = nlmon_close, 117e4fc408eSDaniel Borkmann .ndo_start_xmit = nlmon_xmit, 118e4fc408eSDaniel Borkmann .ndo_get_stats64 = nlmon_get_stats64, 119e4fc408eSDaniel Borkmann .ndo_change_mtu = nlmon_change_mtu, 120e4fc408eSDaniel Borkmann }; 121e4fc408eSDaniel Borkmann 122e4fc408eSDaniel Borkmann static struct netlink_tap nlmon_tap __read_mostly = { 123e4fc408eSDaniel Borkmann .module = THIS_MODULE, 124e4fc408eSDaniel Borkmann }; 125e4fc408eSDaniel Borkmann 126e4fc408eSDaniel Borkmann static void nlmon_setup(struct net_device *dev) 127e4fc408eSDaniel Borkmann { 128e4fc408eSDaniel Borkmann dev->type = ARPHRD_NETLINK; 129e4fc408eSDaniel Borkmann dev->tx_queue_len = 0; 130e4fc408eSDaniel Borkmann 131e4fc408eSDaniel Borkmann dev->netdev_ops = &nlmon_ops; 132e4fc408eSDaniel Borkmann dev->ethtool_ops = &nlmon_ethtool_ops; 133e4fc408eSDaniel Borkmann dev->destructor = free_netdev; 134e4fc408eSDaniel Borkmann 135e4fc408eSDaniel Borkmann dev->features = NETIF_F_FRAGLIST | NETIF_F_HIGHDMA; 136e4fc408eSDaniel Borkmann dev->flags = IFF_NOARP; 137e4fc408eSDaniel Borkmann 138e4fc408eSDaniel Borkmann /* That's rather a softlimit here, which, of course, 139e4fc408eSDaniel Borkmann * can be altered. Not a real MTU, but what is to be 140e4fc408eSDaniel Borkmann * expected in most cases. 141e4fc408eSDaniel Borkmann */ 142e4fc408eSDaniel Borkmann dev->mtu = NLMSG_GOODSIZE; 143e4fc408eSDaniel Borkmann } 144e4fc408eSDaniel Borkmann 145e4fc408eSDaniel Borkmann static __init int nlmon_register(void) 146e4fc408eSDaniel Borkmann { 147e4fc408eSDaniel Borkmann int err; 148e4fc408eSDaniel Borkmann struct net_device *nldev; 149e4fc408eSDaniel Borkmann 150e4fc408eSDaniel Borkmann nldev = nlmon_tap.dev = alloc_netdev(0, "netlink", nlmon_setup); 151e4fc408eSDaniel Borkmann if (unlikely(nldev == NULL)) 152e4fc408eSDaniel Borkmann return -ENOMEM; 153e4fc408eSDaniel Borkmann 154e4fc408eSDaniel Borkmann err = register_netdev(nldev); 155e4fc408eSDaniel Borkmann if (unlikely(err)) 156e4fc408eSDaniel Borkmann free_netdev(nldev); 157e4fc408eSDaniel Borkmann 158e4fc408eSDaniel Borkmann return err; 159e4fc408eSDaniel Borkmann } 160e4fc408eSDaniel Borkmann 161e4fc408eSDaniel Borkmann static __exit void nlmon_unregister(void) 162e4fc408eSDaniel Borkmann { 163e4fc408eSDaniel Borkmann struct net_device *nldev = nlmon_tap.dev; 164e4fc408eSDaniel Borkmann 165e4fc408eSDaniel Borkmann unregister_netdev(nldev); 166e4fc408eSDaniel Borkmann } 167e4fc408eSDaniel Borkmann 168e4fc408eSDaniel Borkmann module_init(nlmon_register); 169e4fc408eSDaniel Borkmann module_exit(nlmon_unregister); 170e4fc408eSDaniel Borkmann 171e4fc408eSDaniel Borkmann MODULE_LICENSE("GPL v2"); 172e4fc408eSDaniel Borkmann MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>"); 173e4fc408eSDaniel Borkmann MODULE_AUTHOR("Mathieu Geli <geli@enseirb.fr>"); 174e4fc408eSDaniel Borkmann MODULE_DESCRIPTION("Netlink monitoring device"); 175