net/core/netdev-genl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 #include <linux/netdevice.h>
   4 #include <linux/notifier.h>
   5 #include <linux/rtnetlink.h>
   6 #include <net/net_namespace.h>
   7 #include <net/sock.h>
   8
   9 #include "netdev-genl-gen.h"
  10
  11 static int
  12 netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff *rsp,
  13                    const struct genl_info *info)
  14 {
  15         void *hdr;
  16
  17         hdr = genlmsg_iput(rsp, info);
  18         if (!hdr)
  19                 return -EMSGSIZE;
  20
  21         if (nla_put_u32(rsp, NETDEV_A_DEV_IFINDEX, netdev->ifindex) ||
  22             nla_put_u64_64bit(rsp, NETDEV_A_DEV_XDP_FEATURES,
  23                               netdev->xdp_features, NETDEV_A_DEV_PAD)) {
  24                 genlmsg_cancel(rsp, hdr);
  25                 return -EINVAL;
  26         }
  27
  28         if (netdev->xdp_features & NETDEV_XDP_ACT_XSK_ZEROCOPY) {
  29                 if (nla_put_u32(rsp, NETDEV_A_DEV_XDP_ZC_MAX_SEGS,
  30                                 netdev->xdp_zc_max_segs)) {
  31                         genlmsg_cancel(rsp, hdr);
  32                         return -EINVAL;
  33                 }
  34         }
  35
  36         genlmsg_end(rsp, hdr);
  37
  38         return 0;
  39 }
  40
  41 static void
  42 netdev_genl_dev_notify(struct net_device *netdev, int cmd)
  43 {
  44         struct genl_info info;
  45         struct sk_buff *ntf;
  46
  47         if (!genl_has_listeners(&netdev_nl_family, dev_net(netdev),
  48                                 NETDEV_NLGRP_MGMT))
  49                 return;
  50
  51         genl_info_init_ntf(&info, &netdev_nl_family, cmd);
  52
  53         ntf = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
  54         if (!ntf)
  55                 return;
  56
  57         if (netdev_nl_dev_fill(netdev, ntf, &info)) {
  58                 nlmsg_free(ntf);
  59                 return;
  60         }
  61
  62         genlmsg_multicast_netns(&netdev_nl_family, dev_net(netdev), ntf,
  63                                 0, NETDEV_NLGRP_MGMT, GFP_KERNEL);
  64 }
  65
  66 int netdev_nl_dev_get_doit(struct sk_buff *skb, struct genl_info *info)
  67 {
  68         struct net_device *netdev;
  69         struct sk_buff *rsp;
  70         u32 ifindex;
  71         int err;
  72
  73         if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_DEV_IFINDEX))
  74                 return -EINVAL;
  75
  76         ifindex = nla_get_u32(info->attrs[NETDEV_A_DEV_IFINDEX]);
  77
  78         rsp = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
  79         if (!rsp)
  80                 return -ENOMEM;
  81
  82         rtnl_lock();
  83
  84         netdev = __dev_get_by_index(genl_info_net(info), ifindex);
  85         if (netdev)
  86                 err = netdev_nl_dev_fill(netdev, rsp, info);
  87         else
  88                 err = -ENODEV;
  89
  90         rtnl_unlock();
  91
  92         if (err)
  93                 goto err_free_msg;
  94
  95         return genlmsg_reply(rsp, info);
  96
  97 err_free_msg:
  98         nlmsg_free(rsp);
  99         return err;
 100 }
 101
 102 int netdev_nl_dev_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 103 {
 104         struct net *net = sock_net(skb->sk);
 105         struct net_device *netdev;
 106         int err = 0;
 107
 108         rtnl_lock();
 109         for_each_netdev_dump(net, netdev, cb->args[0]) {
 110                 err = netdev_nl_dev_fill(netdev, skb, genl_info_dump(cb));
 111                 if (err < 0)
 112                         break;
 113         }
 114         rtnl_unlock();
 115
 116         if (err != -EMSGSIZE)
 117                 return err;
 118
 119         return skb->len;
 120 }
 121
 122 static int netdev_genl_netdevice_event(struct notifier_block *nb,
 123                                        unsigned long event, void *ptr)
 124 {
 125         struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
 126
 127         switch (event) {
 128         case NETDEV_REGISTER:
 129                 netdev_genl_dev_notify(netdev, NETDEV_CMD_DEV_ADD_NTF);
 130                 break;
 131         case NETDEV_UNREGISTER:
 132                 netdev_genl_dev_notify(netdev, NETDEV_CMD_DEV_DEL_NTF);
 133                 break;
 134         case NETDEV_XDP_FEAT_CHANGE:
 135                 netdev_genl_dev_notify(netdev, NETDEV_CMD_DEV_CHANGE_NTF);
 136                 break;
 137         }
 138
 139         return NOTIFY_OK;
 140 }
 141
 142 static struct notifier_block netdev_genl_nb = {
 143         .notifier_call  = netdev_genl_netdevice_event,
 144 };
 145
 146 static int __init netdev_genl_init(void)
 147 {
 148         int err;
 149
 150         err = register_netdevice_notifier(&netdev_genl_nb);
 151         if (err)
 152                 return err;
 153
 154         err = genl_register_family(&netdev_nl_family);
 155         if (err)
 156                 goto err_unreg_ntf;
 157
 158         return 0;
 159
 160 err_unreg_ntf:
 161         unregister_netdevice_notifier(&netdev_genl_nb);
 162         return err;
 163 }
 164
 165 subsys_initcall(netdev_genl_init);