| 1 | |
| 2 | #include <linux/ethtool.h>
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| 3 | #include <linux/module.h>
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| 4 | #include <linux/kernel.h>
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| 5 | #include <linux/netdevice.h>
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| 6 | #include <linux/netlink.h>
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| 7 | #include <net/net_namespace.h>
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| 8 | #include <linux/if_arp.h>
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| 9 | #include <net/rtnetlink.h>
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| 10 |
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| 11 | static netdev_tx_t nlmon_xmit(struct sk_buff *skb, struct net_device *dev)
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| 12 | {
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| 13 | dev_lstats_add(dev, skb->len);
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| 14 |
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| 15 | dev_kfree_skb(skb);
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| 16 |
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| 17 | return NETDEV_TX_OK;
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| 18 | }
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| 19 |
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| 20 | struct nlmon {
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| 21 | struct netlink_tap nt;
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| 22 | };
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| 23 |
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| 24 | static int nlmon_open(struct net_device *dev)
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| 25 | {
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| 26 | struct nlmon *nlmon = netdev_priv(dev);
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| 27 |
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| 28 | nlmon->nt.dev = dev;
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| 29 | nlmon->nt.module = THIS_MODULE;
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| 30 | return netlink_add_tap(&nlmon->nt);
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| 31 | }
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| 32 |
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| 33 | static int nlmon_close(struct net_device *dev)
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| 34 | {
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| 35 | struct nlmon *nlmon = netdev_priv(dev);
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| 36 |
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| 37 | return netlink_remove_tap(&nlmon->nt);
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| 38 | }
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| 39 |
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| 40 | static void
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| 41 | nlmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
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| 42 | {
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| 43 | dev_lstats_read(dev, &stats->rx_packets, &stats->rx_bytes);
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| 44 | }
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| 45 |
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| 46 | static u32 always_on(struct net_device *dev)
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| 47 | {
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| 48 | return 1;
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| 49 | }
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| 50 |
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| 51 | static const struct ethtool_ops nlmon_ethtool_ops = {
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| 52 | .get_link = always_on,
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| 53 | };
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| 54 |
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| 55 | static const struct net_device_ops nlmon_ops = {
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| 56 | .ndo_open = nlmon_open,
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| 57 | .ndo_stop = nlmon_close,
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| 58 | .ndo_start_xmit = nlmon_xmit,
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| 59 | .ndo_get_stats64 = nlmon_get_stats64,
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| 60 | };
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| 61 |
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| 62 | static void nlmon_setup(struct net_device *dev)
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| 63 | {
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| 64 | dev->type = ARPHRD_NETLINK;
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| 65 | dev->priv_flags |= IFF_NO_QUEUE;
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| 66 | dev->lltx = true;
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| 67 |
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| 68 | dev->netdev_ops = &nlmon_ops;
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| 69 | dev->ethtool_ops = &nlmon_ethtool_ops;
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| 70 | dev->needs_free_netdev = true;
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| 71 |
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| 72 | dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA;
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| 73 | dev->flags = IFF_NOARP;
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| 74 | dev->pcpu_stat_type = NETDEV_PCPU_STAT_LSTATS;
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| 75 |
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| 76 | |
| 77 | * can be altered. Not a real MTU, but what is to be
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| 78 | * expected in most cases.
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| 79 |
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| 80 | dev->mtu = NLMSG_GOODSIZE;
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| 81 | dev->min_mtu = sizeof(struct nlmsghdr);
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| 82 | }
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| 83 |
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| 84 | static int nlmon_validate(struct nlattr *tb[], struct nlattr *data[],
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| 85 | struct netlink_ext_ack *extack)
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| 86 | {
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| 87 | if (tb[IFLA_ADDRESS])
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| 88 | return -EINVAL;
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| 89 | return 0;
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| 90 | }
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| 91 |
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| 92 | static struct rtnl_link_ops nlmon_link_ops __read_mostly = {
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| 93 | .kind = "nlmon",
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| 94 | .priv_size = sizeof(struct nlmon),
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| 95 | .setup = nlmon_setup,
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| 96 | .validate = nlmon_validate,
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| 97 | };
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| 98 |
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| 99 | static __init int nlmon_register(void)
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| 100 | {
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| 101 | return rtnl_link_register(&nlmon_link_ops);
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| 102 | }
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| 103 |
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| 104 | static __exit void nlmon_unregister(void)
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| 105 | {
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| 106 | rtnl_link_unregister(&nlmon_link_ops);
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| 107 | }
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| 108 |
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| 109 | module_init(nlmon_register);
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| 110 | module_exit(nlmon_unregister);
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| 111 |
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| 112 | MODULE_LICENSE("GPL v2");
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| 113 | MODULE_AUTHOR("Daniel Borkmann <[email protected]>");
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| 114 | MODULE_AUTHOR("Mathieu Geli <[email protected]>");
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| 115 | MODULE_DESCRIPTION("Netlink monitoring device");
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| 116 | MODULE_ALIAS_RTNL_LINK("nlmon");
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