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