// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      NET3    IP device support routines.
 *
 *      Derived from the IP parts of dev.c 1.0.19
 *              Authors:        Ross Biro
 *                              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *                              Mark Evans, <evansmp@uhura.aston.ac.uk>
 *
 *      Additional Authors:
 *              Alan Cox, <gw4pts@gw4pts.ampr.org>
 *              Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 *      Changes:
 *              Alexey Kuznetsov:       pa_* fields are replaced with ifaddr
 *                                      lists.
 *              Cyrus Durgin:           updated for kmod
 *              Matthias Andree:        in devinet_ioctl, compare label and
 *                                      address (4.4BSD alias style support),
 *                                      fall back to comparing just the label
 *                                      if no match found.
 */


#include <linux/uaccess.h>
#include <linux/bitops.h>
#include <linux/capability.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_addr.h>
#include <linux/if_ether.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/notifier.h>
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#include <linux/slab.h>
#include <linux/hash.h>
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif
#include <linux/kmod.h>
#include <linux/netconf.h>

#include <net/arp.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/ip_fib.h>
#include <net/rtnetlink.h>
#include <net/net_namespace.h>
#include <net/addrconf.h>

#define IPV6ONLY_FLAGS  \
                (IFA_F_NODAD | IFA_F_OPTIMISTIC | IFA_F_DADFAILED | \
                 IFA_F_HOMEADDRESS | IFA_F_TENTATIVE | \
                 IFA_F_MANAGETEMPADDR | IFA_F_STABLE_PRIVACY)

static struct ipv4_devconf ipv4_devconf = {
        .data = {
                [IPV4_DEVCONF_ACCEPT_REDIRECTS - 1] = 1,
                [IPV4_DEVCONF_SEND_REDIRECTS - 1] = 1,
                [IPV4_DEVCONF_SECURE_REDIRECTS - 1] = 1,
                [IPV4_DEVCONF_SHARED_MEDIA - 1] = 1,
                [IPV4_DEVCONF_IGMPV2_UNSOLICITED_REPORT_INTERVAL - 1] = 10000 /*ms*/,
                [IPV4_DEVCONF_IGMPV3_UNSOLICITED_REPORT_INTERVAL - 1] =  1000 /*ms*/,
        },
};

static struct ipv4_devconf ipv4_devconf_dflt = {
        .data = {
                [IPV4_DEVCONF_ACCEPT_REDIRECTS - 1] = 1,
                [IPV4_DEVCONF_SEND_REDIRECTS - 1] = 1,
                [IPV4_DEVCONF_SECURE_REDIRECTS - 1] = 1,
                [IPV4_DEVCONF_SHARED_MEDIA - 1] = 1,
                [IPV4_DEVCONF_ACCEPT_SOURCE_ROUTE - 1] = 1,
                [IPV4_DEVCONF_IGMPV2_UNSOLICITED_REPORT_INTERVAL - 1] = 10000 /*ms*/,
                [IPV4_DEVCONF_IGMPV3_UNSOLICITED_REPORT_INTERVAL - 1] =  1000 /*ms*/,
        },
};

#define IPV4_DEVCONF_DFLT(net, attr) \
        IPV4_DEVCONF((*net->ipv4.devconf_dflt), attr)

static const struct nla_policy ifa_ipv4_policy[IFA_MAX+1] = {
        [IFA_LOCAL]             = { .type = NLA_U32 },
        [IFA_ADDRESS]           = { .type = NLA_U32 },
        [IFA_BROADCAST]         = { .type = NLA_U32 },
        [IFA_LABEL]             = { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
        [IFA_CACHEINFO]         = { .len = sizeof(struct ifa_cacheinfo) },
        [IFA_FLAGS]             = { .type = NLA_U32 },
        [IFA_RT_PRIORITY]       = { .type = NLA_U32 },
        [IFA_TARGET_NETNSID]    = { .type = NLA_S32 },
};

struct inet_fill_args {
        u32 portid;
        u32 seq;
        int event;
        unsigned int flags;
        int netnsid;
        int ifindex;
};

#define IN4_ADDR_HSIZE_SHIFT    8
#define IN4_ADDR_HSIZE          (1U << IN4_ADDR_HSIZE_SHIFT)

static struct hlist_head inet_addr_lst[IN4_ADDR_HSIZE];

static u32 inet_addr_hash(const struct net *net, __be32 addr)
{
        u32 val = (__force u32) addr ^ net_hash_mix(net);

        return hash_32(val, IN4_ADDR_HSIZE_SHIFT);
}

static void inet_hash_insert(struct net *net, struct in_ifaddr *ifa)
{
        u32 hash = inet_addr_hash(net, ifa->ifa_local);

        ASSERT_RTNL();
        hlist_add_head_rcu(&ifa->hash, &inet_addr_lst[hash]);
}

static void inet_hash_remove(struct in_ifaddr *ifa)
{
        ASSERT_RTNL();
        hlist_del_init_rcu(&ifa->hash);
}

/**
 * __ip_dev_find - find the first device with a given source address.
 * @net: the net namespace
 * @addr: the source address
 * @devref: if true, take a reference on the found device
 *
 * If a caller uses devref=false, it should be protected by RCU, or RTNL
 */
struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
{
        struct net_device *result = NULL;
        struct in_ifaddr *ifa;

        rcu_read_lock();
        ifa = inet_lookup_ifaddr_rcu(net, addr);
        if (!ifa) {
                struct flowi4 fl4 = { .daddr = addr };
                struct fib_result res = { 0 };
                struct fib_table *local;

                /* Fallback to FIB local table so that communication
                 * over loopback subnets work.
                 */
                local = fib_get_table(net, RT_TABLE_LOCAL);
                if (local &&
                    !fib_table_lookup(local, &fl4, &res, FIB_LOOKUP_NOREF) &&
                    res.type == RTN_LOCAL)
                        result = FIB_RES_DEV(res);
        } else {
                result = ifa->ifa_dev->dev;
        }
        if (result && devref)
                dev_hold(result);
        rcu_read_unlock();
        return result;
}
EXPORT_SYMBOL(__ip_dev_find);

/* called under RCU lock */
struct in_ifaddr *inet_lookup_ifaddr_rcu(struct net *net, __be32 addr)
{
        u32 hash = inet_addr_hash(net, addr);
        struct in_ifaddr *ifa;

        hlist_for_each_entry_rcu(ifa, &inet_addr_lst[hash], hash)
                if (ifa->ifa_local == addr &&
                    net_eq(dev_net(ifa->ifa_dev->dev), net))
                        return ifa;

        return NULL;
}

static void rtmsg_ifa(int event, struct in_ifaddr *, struct nlmsghdr *, u32);

static BLOCKING_NOTIFIER_HEAD(inetaddr_chain);
static BLOCKING_NOTIFIER_HEAD(inetaddr_validator_chain);
static void inet_del_ifa(struct in_device *in_dev,
                         struct in_ifaddr __rcu **ifap,
                         int destroy);
#ifdef CONFIG_SYSCTL
static int devinet_sysctl_register(struct in_device *idev);
static void devinet_sysctl_unregister(struct in_device *idev);
#else
static int devinet_sysctl_register(struct in_device *idev)
{
        return 0;
}
static void devinet_sysctl_unregister(struct in_device *idev)
{
}
#endif

/* Locks all the inet devices. */

static struct in_ifaddr *inet_alloc_ifa(void)
{
        return kzalloc(sizeof(struct in_ifaddr), GFP_KERNEL);
}

static void inet_rcu_free_ifa(struct rcu_head *head)
{
        struct in_ifaddr *ifa = container_of(head, struct in_ifaddr, rcu_head);
        if (ifa->ifa_dev)
                in_dev_put(ifa->ifa_dev);
        kfree(ifa);
}

static void inet_free_ifa(struct in_ifaddr *ifa)
{
        call_rcu(&ifa->rcu_head, inet_rcu_free_ifa);
}

void in_dev_finish_destroy(struct in_device *idev)
{
        struct net_device *dev = idev->dev;

        WARN_ON(idev->ifa_list);
        WARN_ON(idev->mc_list);
        kfree(rcu_dereference_protected(idev->mc_hash, 1));
#ifdef NET_REFCNT_DEBUG
        pr_debug("%s: %p=%s\n", __func__, idev, dev ? dev->name : "NIL");
#endif
        dev_put(dev);
        if (!idev->dead)
                pr_err("Freeing alive in_device %p\n", idev);
        else
                kfree(idev);
}
EXPORT_SYMBOL(in_dev_finish_destroy);

static struct in_device *inetdev_init(struct net_device *dev)
{
        struct in_device *in_dev;
        int err = -ENOMEM;

        ASSERT_RTNL();

        in_dev = kzalloc(sizeof(*in_dev), GFP_KERNEL);
        if (!in_dev)
                goto out;
        memcpy(&in_dev->cnf, dev_net(dev)->ipv4.devconf_dflt,
                        sizeof(in_dev->cnf));
        in_dev->cnf.sysctl = NULL;
        in_dev->dev = dev;
        in_dev->arp_parms = neigh_parms_alloc(dev, &arp_tbl);
        if (!in_dev->arp_parms)
                goto out_kfree;
        if (IPV4_DEVCONF(in_dev->cnf, FORWARDING))
                dev_disable_lro(dev);
        /* Reference in_dev->dev */
        dev_hold(dev);
        /* Account for reference dev->ip_ptr (below) */
        refcount_set(&in_dev->refcnt, 1);

        err = devinet_sysctl_register(in_dev);
        if (err) {
                in_dev->dead = 1;
                in_dev_put(in_dev);
                in_dev = NULL;
                goto out;
        }
        ip_mc_init_dev(in_dev);
        if (dev->flags & IFF_UP)
                ip_mc_up(in_dev);

        /* we can receive as soon as ip_ptr is set -- do this last */
        rcu_assign_pointer(dev->ip_ptr, in_dev);
out:
        return in_dev ?: ERR_PTR(err);
out_kfree:
        kfree(in_dev);
        in_dev = NULL;
        goto out;
}

static void in_dev_rcu_put(struct rcu_head *head)
{
        struct in_device *idev = container_of(head, struct in_device, rcu_head);
        in_dev_put(idev);
}

static void inetdev_destroy(struct in_device *in_dev)
{
        struct net_device *dev;
        struct in_ifaddr *ifa;

        ASSERT_RTNL();

        dev = in_dev->dev;

        in_dev->dead = 1;

        ip_mc_destroy_dev(in_dev);

        while ((ifa = rtnl_dereference(in_dev->ifa_list)) != NULL) {
                inet_del_ifa(in_dev, &in_dev->ifa_list, 0);
                inet_free_ifa(ifa);
        }

        RCU_INIT_POINTER(dev->ip_ptr, NULL);

        devinet_sysctl_unregister(in_dev);
        neigh_parms_release(&arp_tbl, in_dev->arp_parms);
        arp_ifdown(dev);

        call_rcu(&in_dev->rcu_head, in_dev_rcu_put);
}

int inet_addr_onlink(struct in_device *in_dev, __be32 a, __be32 b)
{
        const struct in_ifaddr *ifa;

        rcu_read_lock();
        in_dev_for_each_ifa_rcu(ifa, in_dev) {
                if (inet_ifa_match(a, ifa)) {
                        if (!b || inet_ifa_match(b, ifa)) {
                                rcu_read_unlock();
                                return 1;
                        }
                }
        }
        rcu_read_unlock();
        return 0;
}

static void __inet_del_ifa(struct in_device *in_dev,
                           struct in_ifaddr __rcu **ifap,
                           int destroy, struct nlmsghdr *nlh, u32 portid)
{
        struct in_ifaddr *promote = NULL;
        struct in_ifaddr *ifa, *ifa1;
        struct in_ifaddr *last_prim;
        struct in_ifaddr *prev_prom = NULL;
        int do_promote = IN_DEV_PROMOTE_SECONDARIES(in_dev);

        ASSERT_RTNL();

        ifa1 = rtnl_dereference(*ifap);
        last_prim = rtnl_dereference(in_dev->ifa_list);
        if (in_dev->dead)
                goto no_promotions;

        /* 1. Deleting primary ifaddr forces deletion all secondaries
         * unless alias promotion is set
         **/

        if (!(ifa1->ifa_flags & IFA_F_SECONDARY)) {
                struct in_ifaddr __rcu **ifap1 = &ifa1->ifa_next;

                while ((ifa = rtnl_dereference(*ifap1)) != NULL) {
                        if (!(ifa->ifa_flags & IFA_F_SECONDARY) &&
                            ifa1->ifa_scope <= ifa->ifa_scope)
                                last_prim = ifa;

                        if (!(ifa->ifa_flags & IFA_F_SECONDARY) ||
                            ifa1->ifa_mask != ifa->ifa_mask ||
                            !inet_ifa_match(ifa1->ifa_address, ifa)) {
                                ifap1 = &ifa->ifa_next;
                                prev_prom = ifa;
                                continue;
                        }

                        if (!do_promote) {
                                inet_hash_remove(ifa);
                                *ifap1 = ifa->ifa_next;

                                rtmsg_ifa(RTM_DELADDR, ifa, nlh, portid);
                                blocking_notifier_call_chain(&inetaddr_chain,
                                                NETDEV_DOWN, ifa);
                                inet_free_ifa(ifa);
                        } else {
                                promote = ifa;
                                break;
                        }
                }
        }

        /* On promotion all secondaries from subnet are changing
         * the primary IP, we must remove all their routes silently
         * and later to add them back with new prefsrc. Do this
         * while all addresses are on the device list.
         */
        for (ifa = promote; ifa; ifa = rtnl_dereference(ifa->ifa_next)) {
                if (ifa1->ifa_mask == ifa->ifa_mask &&
                    inet_ifa_match(ifa1->ifa_address, ifa))
                        fib_del_ifaddr(ifa, ifa1);
        }

no_promotions:
        /* 2. Unlink it */

        *ifap = ifa1->ifa_next;
        inet_hash_remove(ifa1);

        /* 3. Announce address deletion */

        /* Send message first, then call notifier.
           At first sight, FIB update triggered by notifier
           will refer to already deleted ifaddr, that could confuse
           netlink listeners. It is not true: look, gated sees
           that route deleted and if it still thinks that ifaddr
           is valid, it will try to restore deleted routes... Grr.
           So that, this order is correct.
         */
        rtmsg_ifa(RTM_DELADDR, ifa1, nlh, portid);
        blocking_notifier_call_chain(&inetaddr_chain, NETDEV_DOWN, ifa1);

        if (promote) {
                struct in_ifaddr *next_sec;

                next_sec = rtnl_dereference(promote->ifa_next);
                if (prev_prom) {
                        struct in_ifaddr *last_sec;

                        rcu_assign_pointer(prev_prom->ifa_next, next_sec);

                        last_sec = rtnl_dereference(last_prim->ifa_next);
                        rcu_assign_pointer(promote->ifa_next, last_sec);
                        rcu_assign_pointer(last_prim->ifa_next, promote);
                }

                promote->ifa_flags &= ~IFA_F_SECONDARY;
                rtmsg_ifa(RTM_NEWADDR, promote, nlh, portid);
                blocking_notifier_call_chain(&inetaddr_chain,
                                NETDEV_UP, promote);
                for (ifa = next_sec; ifa;
                     ifa = rtnl_dereference(ifa->ifa_next)) {
                        if (ifa1->ifa_mask != ifa->ifa_mask ||
                            !inet_ifa_match(ifa1->ifa_address, ifa))
                                        continue;
                        fib_add_ifaddr(ifa);
                }

        }
        if (destroy)
                inet_free_ifa(ifa1);
}

static void inet_del_ifa(struct in_device *in_dev,
                         struct in_ifaddr __rcu **ifap,
                         int destroy)
{
        __inet_del_ifa(in_dev, ifap, destroy, NULL, 0);
}

static void check_lifetime(struct work_struct *work);

static DECLARE_DELAYED_WORK(check_lifetime_work, check_lifetime);

static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
                             u32 portid, struct netlink_ext_ack *extack)
{
        struct in_ifaddr __rcu **last_primary, **ifap;
        struct in_device *in_dev = ifa->ifa_dev;
        struct in_validator_info ivi;
        struct in_ifaddr *ifa1;
        int ret;

        ASSERT_RTNL();

        if (!ifa->ifa_local) {
                inet_free_ifa(ifa);
                return 0;
        }

        ifa->ifa_flags &= ~IFA_F_SECONDARY;
        last_primary = &in_dev->ifa_list;

        /* Don't set IPv6 only flags to IPv4 addresses */
        ifa->ifa_flags &= ~IPV6ONLY_FLAGS;

        ifap = &in_dev->ifa_list;
        ifa1 = rtnl_dereference(*ifap);

        while (ifa1) {
                if (!(ifa1->ifa_flags & IFA_F_SECONDARY) &&
                    ifa->ifa_scope <= ifa1->ifa_scope)
                        last_primary = &ifa1->ifa_next;
                if (ifa1->ifa_mask == ifa->ifa_mask &&
                    inet_ifa_match(ifa1->ifa_address, ifa)) {
                        if (ifa1->ifa_local == ifa->ifa_local) {
                                inet_free_ifa(ifa);
                                return -EEXIST;
                        }
                        if (ifa1->ifa_scope != ifa->ifa_scope) {
                                inet_free_ifa(ifa);
                                return -EINVAL;
                        }
                        ifa->ifa_flags |= IFA_F_SECONDARY;
                }

                ifap = &ifa1->ifa_next;
                ifa1 = rtnl_dereference(*ifap);
        }

        /* Allow any devices that wish to register ifaddr validtors to weigh
         * in now, before changes are committed.  The rntl lock is serializing
         * access here, so the state should not change between a validator call
         * and a final notify on commit.  This isn't invoked on promotion under
         * the assumption that validators are checking the address itself, and
         * not the flags.
         */
        ivi.ivi_addr = ifa->ifa_address;
        ivi.ivi_dev = ifa->ifa_dev;
        ivi.extack = extack;
        ret = blocking_notifier_call_chain(&inetaddr_validator_chain,
                                           NETDEV_UP, &ivi);
        ret = notifier_to_errno(ret);
        if (ret) {
                inet_free_ifa(ifa);
                return ret;
        }

        if (!(ifa->ifa_flags & IFA_F_SECONDARY)) {
                prandom_seed((__force u32) ifa->ifa_local);
                ifap = last_primary;
        }

        rcu_assign_pointer(ifa->ifa_next, *ifap);
        rcu_assign_pointer(*ifap, ifa);

        inet_hash_insert(dev_net(in_dev->dev), ifa);

        cancel_delayed_work(&check_lifetime_work);
        queue_delayed_work(system_power_efficient_wq, &check_lifetime_work, 0);

        /* Send message first, then call notifier.
           Notifier will trigger FIB update, so that
           listeners of netlink will know about new ifaddr */
        rtmsg_ifa(RTM_NEWADDR, ifa, nlh, portid);
        blocking_notifier_call_chain(&inetaddr_chain, NETDEV_UP, ifa);

        return 0;
}

static int inet_insert_ifa(struct in_ifaddr *ifa)
{
        return __inet_insert_ifa(ifa, NULL, 0, NULL);
}

static int inet_set_ifa(struct net_device *dev, struct in_ifaddr *ifa)
{
        struct in_device *in_dev = __in_dev_get_rtnl(dev);

        ASSERT_RTNL();

        if (!in_dev) {
                inet_free_ifa(ifa);
                return -ENOBUFS;
        }
        ipv4_devconf_setall(in_dev);
        neigh_parms_data_state_setall(in_dev->arp_parms);
        if (ifa->ifa_dev != in_dev) {
                WARN_ON(ifa->ifa_dev);
                in_dev_hold(in_dev);
                ifa->ifa_dev = in_dev;
        }
        if (ipv4_is_loopback(ifa->ifa_local))
                ifa->ifa_scope = RT_SCOPE_HOST;
        return inet_insert_ifa(ifa);
}

/* Caller must hold RCU or RTNL :
 * We dont take a reference on found in_device
 */
struct in_device *inetdev_by_index(struct net *net, int ifindex)
{
        struct net_device *dev;
        struct in_device *in_dev = NULL;

        rcu_read_lock();
        dev = dev_get_by_index_rcu(net, ifindex);
        if (dev)
                in_dev = rcu_dereference_rtnl(dev->ip_ptr);
        rcu_read_unlock();
        return in_dev;
}
EXPORT_SYMBOL(inetdev_by_index);

/* Called only from RTNL semaphored context. No locks. */

struct in_ifaddr *inet_ifa_byprefix(struct in_device *in_dev, __be32 prefix,
                                    __be32 mask)
{
        struct in_ifaddr *ifa;

        ASSERT_RTNL();

        in_dev_for_each_ifa_rtnl(ifa, in_dev) {
                if (ifa->ifa_mask == mask && inet_ifa_match(prefix, ifa))
                        return ifa;
        }
        return NULL;
}

static int ip_mc_config(struct sock *sk, bool join, const struct in_ifaddr *ifa)
{
        struct ip_mreqn mreq = {
                .imr_multiaddr.s_addr = ifa->ifa_address,
                .imr_ifindex = ifa->ifa_dev->dev->ifindex,
        };
        int ret;

        ASSERT_RTNL();

        lock_sock(sk);
        if (join)
                ret = ip_mc_join_group(sk, &mreq);
        else
                ret = ip_mc_leave_group(sk, &mreq);
        release_sock(sk);

        return ret;
}

static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
                            struct netlink_ext_ack *extack)
{
        struct net *net = sock_net(skb->sk);
        struct in_ifaddr __rcu **ifap;
        struct nlattr *tb[IFA_MAX+1];
        struct in_device *in_dev;
        struct ifaddrmsg *ifm;
        struct in_ifaddr *ifa;

        int err = -EINVAL;

        ASSERT_RTNL();

        err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
                                     ifa_ipv4_policy, extack);
        if (err < 0)
                goto errout;

        ifm = nlmsg_data(nlh);
        in_dev = inetdev_by_index(net, ifm->ifa_index);
        if (!in_dev) {
                err = -ENODEV;
                goto errout;
        }

        for (ifap = &in_dev->ifa_list; (ifa = rtnl_dereference(*ifap)) != NULL;
             ifap = &ifa->ifa_next) {
                if (tb[IFA_LOCAL] &&
                    ifa->ifa_local != nla_get_in_addr(tb[IFA_LOCAL]))
                        continue;

                if (tb[IFA_LABEL] && nla_strcmp(tb[IFA_LABEL], ifa->ifa_label))
                        continue;

                if (tb[IFA_ADDRESS] &&
                    (ifm->ifa_prefixlen != ifa->ifa_prefixlen ||
                    !inet_ifa_match(nla_get_in_addr(tb[IFA_ADDRESS]), ifa)))
                        continue;

                if (ipv4_is_multicast(ifa->ifa_address))
                        ip_mc_config(net->ipv4.mc_autojoin_sk, false, ifa);
                __inet_del_ifa(in_dev, ifap, 1, nlh, NETLINK_CB(skb).portid);
                return 0;
        }

        err = -EADDRNOTAVAIL;
errout:
        return err;
}

#define INFINITY_LIFE_TIME      0xFFFFFFFF

static void check_lifetime(struct work_struct *work)
{
        unsigned long now, next, next_sec, next_sched;
        struct in_ifaddr *ifa;
        struct hlist_node *n;
        int i;

        now = jiffies;
        next = round_jiffies_up(now + ADDR_CHECK_FREQUENCY);

        for (i = 0; i < IN4_ADDR_HSIZE; i++) {
                bool change_needed = false;

                rcu_read_lock();
                hlist_for_each_entry_rcu(ifa, &inet_addr_lst[i], hash) {
                        unsigned long age;

                        if (ifa->ifa_flags & IFA_F_PERMANENT)
                                continue;

                        /* We try to batch several events at once. */
                        age = (now - ifa->ifa_tstamp +
                               ADDRCONF_TIMER_FUZZ_MINUS) / HZ;

                        if (ifa->ifa_valid_lft != INFINITY_LIFE_TIME &&
                            age >= ifa->ifa_valid_lft) {
                                change_needed = true;
                        } else if (ifa->ifa_preferred_lft ==
                                   INFINITY_LIFE_TIME) {
                                continue;
                        } else if (age >= ifa->ifa_preferred_lft) {
                                if (time_before(ifa->ifa_tstamp +
                                                ifa->ifa_valid_lft * HZ, next))
                                        next = ifa->ifa_tstamp +
                                               ifa->ifa_valid_lft * HZ;

                                if (!(ifa->ifa_flags & IFA_F_DEPRECATED))
                                        change_needed = true;
                        } else if (time_before(ifa->ifa_tstamp +
                                               ifa->ifa_preferred_lft * HZ,
                                               next)) {
                                next = ifa->ifa_tstamp +
                                       ifa->ifa_preferred_lft * HZ;
                        }
                }
                rcu_read_unlock();
                if (!change_needed)
                        continue;
                rtnl_lock();
                hlist_for_each_entry_safe(ifa, n, &inet_addr_lst[i], hash) {
                        unsigned long age;

                        if (ifa->ifa_flags & IFA_F_PERMANENT)
                                continue;

                        /* We try to batch several events at once. */
                        age = (now - ifa->ifa_tstamp +
                               ADDRCONF_TIMER_FUZZ_MINUS) / HZ;

                        if (ifa->ifa_valid_lft != INFINITY_LIFE_TIME &&
                            age >= ifa->ifa_valid_lft) {
                                struct in_ifaddr __rcu **ifap;
                                struct in_ifaddr *tmp;

                                ifap = &ifa->ifa_dev->ifa_list;
                                tmp = rtnl_dereference(*ifap);
                                while (tmp) {
                                        if (tmp == ifa) {
                                                inet_del_ifa(ifa->ifa_dev,
                                                             ifap, 1);
                                                break;
                                        }
                                        ifap = &tmp->ifa_next;
                                        tmp = rtnl_dereference(*ifap);
                                }
                        } else if (ifa->ifa_preferred_lft !=
                                   INFINITY_LIFE_TIME &&
                                   age >= ifa->ifa_preferred_lft &&
                                   !(ifa->ifa_flags & IFA_F_DEPRECATED)) {
                                ifa->ifa_flags |= IFA_F_DEPRECATED;
                                rtmsg_ifa(RTM_NEWADDR, ifa, NULL, 0);
                        }
                }
                rtnl_unlock();
        }

        next_sec = round_jiffies_up(next);
        next_sched = next;

        /* If rounded timeout is accurate enough, accept it. */
        if (time_before(next_sec, next + ADDRCONF_TIMER_FUZZ))
                next_sched = next_sec;

        now = jiffies;
        /* And minimum interval is ADDRCONF_TIMER_FUZZ_MAX. */
        if (time_before(next_sched, now + ADDRCONF_TIMER_FUZZ_MAX))
                next_sched = now + ADDRCONF_TIMER_FUZZ_MAX;

        queue_delayed_work(system_power_efficient_wq, &check_lifetime_work,
                        next_sched - now);
}

static void set_ifa_lifetime(struct in_ifaddr *ifa, __u32 valid_lft,
                             __u32 prefered_lft)
{
        unsigned long timeout;

        ifa->ifa_flags &= ~(IFA_F_PERMANENT | IFA_F_DEPRECATED);

        timeout = addrconf_timeout_fixup(valid_lft, HZ);
        if (addrconf_finite_timeout(timeout))
                ifa->ifa_valid_lft = timeout;
        else
                ifa->ifa_flags |= IFA_F_PERMANENT;

        timeout = addrconf_timeout_fixup(prefered_lft, HZ);
        if (addrconf_finite_timeout(timeout)) {
                if (timeout == 0)
                        ifa->ifa_flags |= IFA_F_DEPRECATED;
                ifa->ifa_preferred_lft = timeout;
        }
        ifa->ifa_tstamp = jiffies;
        if (!ifa->ifa_cstamp)
                ifa->ifa_cstamp = ifa->ifa_tstamp;
}

static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh,
                                       __u32 *pvalid_lft, __u32 *pprefered_lft,
                                       struct netlink_ext_ack *extack)
{
        struct nlattr *tb[IFA_MAX+1];
        struct in_ifaddr *ifa;
        struct ifaddrmsg *ifm;
        struct net_device *dev;
        struct in_device *in_dev;
        int err;

        err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
                                     ifa_ipv4_policy, extack);
        if (err < 0)
                goto errout;

        ifm = nlmsg_data(nlh);
        err = -EINVAL;
        if (ifm->ifa_prefixlen > 32 || !tb[IFA_LOCAL])
                goto errout;

        dev = __dev_get_by_index(net, ifm->ifa_index);
        err = -ENODEV;
        if (!dev)
                goto errout;

        in_dev = __in_dev_get_rtnl(dev);
        err = -ENOBUFS;
        if (!in_dev)
                goto errout;

        ifa = inet_alloc_ifa();
        if (!ifa)
                /*
                 * A potential indev allocation can be left alive, it stays
                 * assigned to its device and is destroy with it.
                 */
                goto errout;

        ipv4_devconf_setall(in_dev);
        neigh_parms_data_state_setall(in_dev->arp_parms);
        in_dev_hold(in_dev);

        if (!tb[IFA_ADDRESS])
                tb[IFA_ADDRESS] = tb[IFA_LOCAL];

        INIT_HLIST_NODE(&ifa->hash);
        ifa->ifa_prefixlen = ifm->ifa_prefixlen;
        ifa->ifa_mask = inet_make_mask(ifm->ifa_prefixlen);
        ifa->ifa_flags = tb[IFA_FLAGS] ? nla_get_u32(tb[IFA_FLAGS]) :
                                         ifm->ifa_flags;
        ifa->ifa_scope = ifm->ifa_scope;
        ifa->ifa_dev = in_dev;

        ifa->ifa_local = nla_get_in_addr(tb[IFA_LOCAL]);
        ifa->ifa_address = nla_get_in_addr(tb[IFA_ADDRESS]);

        if (tb[IFA_BROADCAST])
                ifa->ifa_broadcast = nla_get_in_addr(tb[IFA_BROADCAST]);

        if (tb[IFA_LABEL])
                nla_strlcpy(ifa->ifa_label, tb[IFA_LABEL], IFNAMSIZ);
        else
                memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);

        if (tb[IFA_RT_PRIORITY])
                ifa->ifa_rt_priority = nla_get_u32(tb[IFA_RT_PRIORITY]);

        if (tb[IFA_CACHEINFO]) {
                struct ifa_cacheinfo *ci;

                ci = nla_data(tb[IFA_CACHEINFO]);
                if (!ci->ifa_valid || ci->ifa_prefered > ci->ifa_valid) {
                        err = -EINVAL;
                        goto errout_free;
                }
                *pvalid_lft = ci->ifa_valid;
                *pprefered_lft = ci->ifa_prefered;
        }

        return ifa;

errout_free:
        inet_free_ifa(ifa);
errout:
        return ERR_PTR(err);
}

static struct in_ifaddr *find_matching_ifa(struct in_ifaddr *ifa)
{
        struct in_device *in_dev = ifa->ifa_dev;
        struct in_ifaddr *ifa1;

        if (!ifa->ifa_local)
                return NULL;

        in_dev_for_each_ifa_rtnl(ifa1, in_dev) {
                if (ifa1->ifa_mask == ifa->ifa_mask &&
                    inet_ifa_match(ifa1->ifa_address, ifa) &&
                    ifa1->ifa_local == ifa->ifa_local)
                        return ifa1;
        }
        return NULL;
}

static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
                            struct netlink_ext_ack *extack)
{
        struct net *net = sock_net(skb->sk);
        struct in_ifaddr *ifa;
        struct in_ifaddr *ifa_existing;
        __u32 valid_lft = INFINITY_LIFE_TIME;
        __u32 prefered_lft = INFINITY_LIFE_TIME;

        ASSERT_RTNL();

        ifa = rtm_to_ifaddr(net, nlh, &valid_lft, &prefered_lft, extack);
        if (IS_ERR(ifa))
                return PTR_ERR(ifa);

        ifa_existing = find_matching_ifa(ifa);
        if (!ifa_existing) {
                /* It would be best to check for !NLM_F_CREATE here but
                 * userspace already relies on not having to provide this.
                 */
                set_ifa_lifetime(ifa, valid_lft, prefered_lft);
                if (ifa->ifa_flags & IFA_F_MCAUTOJOIN) {
                        int ret = ip_mc_config(net->ipv4.mc_autojoin_sk,
                                               true, ifa);

                        if (ret < 0) {
                                inet_free_ifa(ifa);
                                return ret;
                        }
                }
                return __inet_insert_ifa(ifa, nlh, NETLINK_CB(skb).portid,
                                         extack);
        } else {
                u32 new_metric = ifa->ifa_rt_priority;

                inet_free_ifa(ifa);

                if (nlh->nlmsg_flags & NLM_F_EXCL ||
                    !(nlh->nlmsg_flags & NLM_F_REPLACE))
                        return -EEXIST;
                ifa = ifa_existing;

                if (ifa->ifa_rt_priority != new_metric) {
                        fib_modify_prefix_metric(ifa, new_metric);
                        ifa->ifa_rt_priority = new_metric;
                }

                set_ifa_lifetime(ifa, valid_lft, prefered_lft);
                cancel_delayed_work(&check_lifetime_work);
                queue_delayed_work(system_power_efficient_wq,
                                &check_lifetime_work, 0);
                rtmsg_ifa(RTM_NEWADDR, ifa, nlh, NETLINK_CB(skb).portid);
        }
        return 0;
}

/*
 *      Determine a default network mask, based on the IP address.
 */

static int inet_abc_len(__be32 addr)
{
        int rc = -1;    /* Something else, probably a multicast. */

        if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
                rc = 0;
        else {
                __u32 haddr = ntohl(addr);
                if (IN_CLASSA(haddr))
                        rc = 8;
                else if (IN_CLASSB(haddr))
                        rc = 16;
                else if (IN_CLASSC(haddr))
                        rc = 24;
                else if (IN_CLASSE(haddr))
                        rc = 32;
        }

        return rc;
}

int devinet_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr)
{
        struct sockaddr_in sin_orig;
        struct sockaddr_in *sin = (struct sockaddr_in *)&ifr->ifr_addr;
        struct in_ifaddr __rcu **ifap = NULL;
        struct in_device *in_dev;
        struct in_ifaddr *ifa = NULL;
        struct net_device *dev;
        char *colon;
        int ret = -EFAULT;
        int tryaddrmatch = 0;

        ifr->ifr_name[IFNAMSIZ - 1] = 0;

        /* save original address for comparison */
        memcpy(&sin_orig, sin, sizeof(*sin));

        colon = strchr(ifr->ifr_name, ':');
        if (colon)
                *colon = 0;

        dev_load(net, ifr->ifr_name);

        switch (cmd) {
        case SIOCGIFADDR:       /* Get interface address */
        case SIOCGIFBRDADDR:    /* Get the broadcast address */
        case SIOCGIFDSTADDR:    /* Get the destination address */
        case SIOCGIFNETMASK:    /* Get the netmask for the interface */
                /* Note that these ioctls will not sleep,
                   so that we do not impose a lock.
                   One day we will be forced to put shlock here (I mean SMP)
                 */
                tryaddrmatch = (sin_orig.sin_family == AF_INET);
                memset(sin, 0, sizeof(*sin));
                sin->sin_family = AF_INET;
                break;

        case SIOCSIFFLAGS:
                ret = -EPERM;
                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                        goto out;
                break;
        case SIOCSIFADDR:       /* Set interface address (and family) */
        case SIOCSIFBRDADDR:    /* Set the broadcast address */
        case SIOCSIFDSTADDR:    /* Set the destination address */
        case SIOCSIFNETMASK:    /* Set the netmask for the interface */
                ret = -EPERM;
                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                        goto out;
                ret = -EINVAL;
                if (sin->sin_family != AF_INET)
                        goto out;
                break;
        default:
                ret = -EINVAL;
                goto out;
        }

        rtnl_lock();

        ret = -ENODEV;
        dev = __dev_get_by_name(net, ifr->ifr_name);
        if (!dev)
                goto done;

        if (colon)
                *colon = ':';

        in_dev = __in_dev_get_rtnl(dev);
        if (in_dev) {
                if (tryaddrmatch) {
                        /* Matthias Andree */
                        /* compare label and address (4.4BSD style) */
                        /* note: we only do this for a limited set of ioctls
                           and only if the original address family was AF_INET.
                           This is checked above. */

                        for (ifap = &in_dev->ifa_list;
                             (ifa = rtnl_dereference(*ifap)) != NULL;
                             ifap = &ifa->ifa_next) {
                                if (!strcmp(ifr->ifr_name, ifa->ifa_label) &&
                                    sin_orig.sin_addr.s_addr ==
                                                        ifa->ifa_local) {
                                        break; /* found */
                                }
                        }
                }
                /* we didn't get a match, maybe the application is
                   4.3BSD-style and passed in junk so we fall back to
                   comparing just the label */
                if (!ifa) {
                        for (ifap = &in_dev->ifa_list;
                             (ifa = rtnl_dereference(*ifap)) != NULL;
                             ifap = &ifa->ifa_next)
                                if (!strcmp(ifr->ifr_name, ifa->ifa_label))
                                        break;
                }
        }

        ret = -EADDRNOTAVAIL;
        if (!ifa && cmd != SIOCSIFADDR && cmd != SIOCSIFFLAGS)
                goto done;

        switch (cmd) {
        case SIOCGIFADDR:       /* Get interface address */
                ret = 0;
                sin->sin_addr.s_addr = ifa->ifa_local;
                break;

        case SIOCGIFBRDADDR:    /* Get the broadcast address */
                ret = 0;
                sin->sin_addr.s_addr = ifa->ifa_broadcast;
                break;

        case SIOCGIFDSTADDR:    /* Get the destination address */
                ret = 0;
                sin->sin_addr.s_addr = ifa->ifa_address;
                break;

        case SIOCGIFNETMASK:    /* Get the netmask for the interface */
                ret = 0;
                sin->sin_addr.s_addr = ifa->ifa_mask;
                break;

        case SIOCSIFFLAGS:
                if (colon) {
                        ret = -EADDRNOTAVAIL;
                        if (!ifa)
                                break;
                        ret = 0;
                        if (!(ifr->ifr_flags & IFF_UP))
                                inet_del_ifa(in_dev, ifap, 1);
                        break;
                }
                ret = dev_change_flags(dev, ifr->ifr_flags, NULL);
                break;

        case SIOCSIFADDR:       /* Set interface address (and family) */
                ret = -EINVAL;
                if (inet_abc_len(sin->sin_addr.s_addr) < 0)
                        break;

                if (!ifa) {
                        ret = -ENOBUFS;
                        ifa = inet_alloc_ifa();
                        if (!ifa)
                                break;
                        INIT_HLIST_NODE(&ifa->hash);
                        if (colon)
                                memcpy(ifa->ifa_label, ifr->ifr_name, IFNAMSIZ);
                        else
                                memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
                } else {
                        ret = 0;
                        if (ifa->ifa_local == sin->sin_addr.s_addr)
                                break;
                        inet_del_ifa(in_dev, ifap, 0);
                        ifa->ifa_broadcast = 0;
                        ifa->ifa_scope = 0;
                }

                ifa->ifa_address = ifa->ifa_local = sin->sin_addr.s_addr;

                if (!(dev->flags & IFF_POINTOPOINT)) {
                        ifa->ifa_prefixlen = inet_abc_len(ifa->ifa_address);
                        ifa->ifa_mask = inet_make_mask(ifa->ifa_prefixlen);
                        if ((dev->flags & IFF_BROADCAST) &&
                            ifa->ifa_prefixlen < 31)
                                ifa->ifa_broadcast = ifa->ifa_address |
                                                     ~ifa->ifa_mask;
                } else {
                        ifa->ifa_prefixlen = 32;
                        ifa->ifa_mask = inet_make_mask(32);
                }
                set_ifa_lifetime(ifa, INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
                ret = inet_set_ifa(dev, ifa);
                break;

        case SIOCSIFBRDADDR:    /* Set the broadcast address */
                ret = 0;
                if (ifa->ifa_broadcast != sin->sin_addr.s_addr) {
                        inet_del_ifa(in_dev, ifap, 0);
                        ifa->ifa_broadcast = sin->sin_addr.s_addr;
                        inet_insert_ifa(ifa);
                }
                break;

        case SIOCSIFDSTADDR:    /* Set the destination address */
                ret = 0;
                if (ifa->ifa_address == sin->sin_addr.s_addr)
                        break;
                ret = -EINVAL;
                if (inet_abc_len(sin->sin_addr.s_addr) < 0)
                        break;
                ret = 0;
                inet_del_ifa(in_dev, ifap, 0);
                ifa->ifa_address = sin->sin_addr.s_addr;
                inet_insert_ifa(ifa);
                break;

        case SIOCSIFNETMASK:    /* Set the netmask for the interface */

                /*
                 *      The mask we set must be legal.
                 */
                ret = -EINVAL;
                if (bad_mask(sin->sin_addr.s_addr, 0))
                        break;
                ret = 0;
                if (ifa->ifa_mask != sin->sin_addr.s_addr) {
                        __be32 old_mask = ifa->ifa_mask;
                        inet_del_ifa(in_dev, ifap, 0);
                        ifa->ifa_mask = sin->sin_addr.s_addr;
                        ifa->ifa_prefixlen = inet_mask_len(ifa->ifa_mask);

                        /* See if current broadcast address matches
                         * with current netmask, then recalculate
                         * the broadcast address. Otherwise it's a
                         * funny address, so don't touch it since
                         * the user seems to know what (s)he's doing...
                         */
                        if ((dev->flags & IFF_BROADCAST) &&
                            (ifa->ifa_prefixlen < 31) &&
                            (ifa->ifa_broadcast ==
                             (ifa->ifa_local|~old_mask))) {
                                ifa->ifa_broadcast = (ifa->ifa_local |
                                                      ~sin->sin_addr.s_addr);
                        }
                        inet_insert_ifa(ifa);
                }
                break;
        }
done:
        rtnl_unlock();
out:
        return ret;
}

static int inet_gifconf(struct net_device *dev, char __user *buf, int len, int size)
{
        struct in_device *in_dev = __in_dev_get_rtnl(dev);
        const struct in_ifaddr *ifa;
        struct ifreq ifr;
        int done = 0;

        if (WARN_ON(size > sizeof(struct ifreq)))
                goto out;

        if (!in_dev)
                goto out;

        in_dev_for_each_ifa_rtnl(ifa, in_dev) {
                if (!buf) {
                        done += size;
                        continue;
                }
                if (len < size)
                        break;
                memset(&ifr, 0, sizeof(struct ifreq));
                strcpy(ifr.ifr_name, ifa->ifa_label);

                (*(struct sockaddr_in *)&ifr.ifr_addr).sin_family = AF_INET;
                (*(struct sockaddr_in *)&ifr.ifr_addr).sin_addr.s_addr =
                                                                ifa->ifa_local;

                if (copy_to_user(buf + done, &ifr, size)) {
                        done = -EFAULT;
                        break;
                }
                len  -= size;
                done += size;
        }
out:
        return done;
}

static __be32 in_dev_select_addr(const struct in_device *in_dev,
                                 int scope)
{
        const struct in_ifaddr *ifa;

        in_dev_for_each_ifa_rcu(ifa, in_dev) {
                if (ifa->ifa_flags & IFA_F_SECONDARY)
                        continue;
                if (ifa->ifa_scope != RT_SCOPE_LINK &&
                    ifa->ifa_scope <= scope)
                        return ifa->ifa_local;
        }

        return 0;
}

__be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope)
{
        const struct in_ifaddr *ifa;
        __be32 addr = 0;
        unsigned char localnet_scope = RT_SCOPE_HOST;
        struct in_device *in_dev;
        struct net *net = dev_net(dev);
        int master_idx;

        rcu_read_lock();
        in_dev = __in_dev_get_rcu(dev);
        if (!in_dev)
                goto no_in_dev;

        if (unlikely(IN_DEV_ROUTE_LOCALNET(in_dev)))
                localnet_scope = RT_SCOPE_LINK;

        in_dev_for_each_ifa_rcu(ifa, in_dev) {
                if (ifa->ifa_flags & IFA_F_SECONDARY)
                        continue;
                if (min(ifa->ifa_scope, localnet_scope) > scope)
                        continue;
                if (!dst || inet_ifa_match(dst, ifa)) {
                        addr = ifa->ifa_local;
                        break;
                }
                if (!addr)
                        addr = ifa->ifa_local;
        }

        if (addr)
                goto out_unlock;
no_in_dev:
        master_idx = l3mdev_master_ifindex_rcu(dev);

        /* For VRFs, the VRF device takes the place of the loopback device,
         * with addresses on it being preferred.  Note in such cases the
         * loopback device will be among the devices that fail the master_idx
         * equality check in the loop below.
         */
        if (master_idx &&
            (dev = dev_get_by_index_rcu(net, master_idx)) &&
            (in_dev = __in_dev_get_rcu(dev))) {
                addr = in_dev_select_addr(in_dev, scope);
                if (addr)
                        goto out_unlock;
        }

        /* Not loopback addresses on loopback should be preferred
           in this case. It is important that lo is the first interface
           in dev_base list.
         */
        for_each_netdev_rcu(net, dev) {
                if (l3mdev_master_ifindex_rcu(dev) != master_idx)
                        continue;

                in_dev = __in_dev_get_rcu(dev);
                if (!in_dev)
                        continue;

                addr = in_dev_select_addr(in_dev, scope);
                if (addr)
                        goto out_unlock;
        }
out_unlock:
        rcu_read_unlock();
        return addr;
}
EXPORT_SYMBOL(inet_select_addr);

static __be32 confirm_addr_indev(struct in_device *in_dev, __be32 dst,
                              __be32 local, int scope)
{
        unsigned char localnet_scope = RT_SCOPE_HOST;
        const struct in_ifaddr *ifa;
        __be32 addr = 0;
        int same = 0;

        if (unlikely(IN_DEV_ROUTE_LOCALNET(in_dev)))
                localnet_scope = RT_SCOPE_LINK;

        in_dev_for_each_ifa_rcu(ifa, in_dev) {
                unsigned char min_scope = min(ifa->ifa_scope, localnet_scope);

                if (!addr &&
                    (local == ifa->ifa_local || !local) &&
                    min_scope <= scope) {
                        addr = ifa->ifa_local;
                        if (same)
                                break;
                }
                if (!same) {
                        same = (!local || inet_ifa_match(local, ifa)) &&
                                (!dst || inet_ifa_match(dst, ifa));
                        if (same && addr) {
                                if (local || !dst)
                                        break;
                                /* Is the selected addr into dst subnet? */
                                if (inet_ifa_match(addr, ifa))
                                        break;
                                /* No, then can we use new local src? */
                                if (min_scope <= scope) {
                                        addr = ifa->ifa_local;
                                        break;
                                }
                                /* search for large dst subnet for addr */
                                same = 0;
                        }
                }
        }

        return same ? addr : 0;
}

/*
 * Confirm that local IP address exists using wildcards:
 * - net: netns to check, cannot be NULL
 * - in_dev: only on this interface, NULL=any interface
 * - dst: only in the same subnet as dst, 0=any dst
 * - local: address, 0=autoselect the local address
 * - scope: maximum allowed scope value for the local address
 */
__be32 inet_confirm_addr(struct net *net, struct in_device *in_dev,
                         __be32 dst, __be32 local, int scope)
{
        __be32 addr = 0;
        struct net_device *dev;

        if (in_dev)
                return confirm_addr_indev(in_dev, dst, local, scope);

        rcu_read_lock();
        for_each_netdev_rcu(net, dev) {
                in_dev = __in_dev_get_rcu(dev);
                if (in_dev) {
                        addr = confirm_addr_indev(in_dev, dst, local, scope);
                        if (addr)
                                break;
                }
        }
        rcu_read_unlock();

        return addr;
}
EXPORT_SYMBOL(inet_confirm_addr);

/*
 *      Device notifier
 */

int register_inetaddr_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&inetaddr_chain, nb);
}
EXPORT_SYMBOL(register_inetaddr_notifier);

int unregister_inetaddr_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(&inetaddr_chain, nb);
}
EXPORT_SYMBOL(unregister_inetaddr_notifier);

int register_inetaddr_validator_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&inetaddr_validator_chain, nb);
}
EXPORT_SYMBOL(register_inetaddr_validator_notifier);

int unregister_inetaddr_validator_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(&inetaddr_validator_chain,
            nb);
}
EXPORT_SYMBOL(unregister_inetaddr_validator_notifier);

/* Rename ifa_labels for a device name change. Make some effort to preserve
 * existing alias numbering and to create unique labels if possible.
*/
static void inetdev_changename(struct net_device *dev, struct in_device *in_dev)
{
        struct in_ifaddr *ifa;
        int named = 0;

        in_dev_for_each_ifa_rtnl(ifa, in_dev) {
                char old[IFNAMSIZ], *dot;

                memcpy(old, ifa->ifa_label, IFNAMSIZ);
                memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
                if (named++ == 0)
                        goto skip;
                dot = strchr(old, ':');
                if (!dot) {
                        sprintf(old, ":%d", named);
                        dot = old;
                }
                if (strlen(dot) + strlen(dev->name) < IFNAMSIZ)
                        strcat(ifa->ifa_label, dot);
                else
                        strcpy(ifa->ifa_label + (IFNAMSIZ - strlen(dot) - 1), dot);
skip:
                rtmsg_ifa(RTM_NEWADDR, ifa, NULL, 0);
        }
}

static bool inetdev_valid_mtu(unsigned int mtu)
{
        return mtu >= IPV4_MIN_MTU;
}

static void inetdev_send_gratuitous_arp(struct net_device *dev,
                                        struct in_device *in_dev)

{
        const struct in_ifaddr *ifa;

        in_dev_for_each_ifa_rtnl(ifa, in_dev) {
                arp_send(ARPOP_REQUEST, ETH_P_ARP,
                         ifa->ifa_local, dev,
                         ifa->ifa_local, NULL,
                         dev->dev_addr, NULL);
        }
}

/* Called only under RTNL semaphore */

static int inetdev_event(struct notifier_block *this, unsigned long event,
                         void *ptr)
{
        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
        struct in_device *in_dev = __in_dev_get_rtnl(dev);

        ASSERT_RTNL();

        if (!in_dev) {
                if (event == NETDEV_REGISTER) {
                        in_dev = inetdev_init(dev);
                        if (IS_ERR(in_dev))
                                return notifier_from_errno(PTR_ERR(in_dev));
                        if (dev->flags & IFF_LOOPBACK) {
                                IN_DEV_CONF_SET(in_dev, NOXFRM, 1);
                                IN_DEV_CONF_SET(in_dev, NOPOLICY, 1);
                        }
                } else if (event == NETDEV_CHANGEMTU) {
                        /* Re-enabling IP */
                        if (inetdev_valid_mtu(dev->mtu))
                                in_dev = inetdev_init(dev);
                }
                goto out;
        }

        switch (event) {
        case NETDEV_REGISTER:
                pr_debug("%s: bug\n", __func__);
                RCU_INIT_POINTER(dev->ip_ptr, NULL);
                break;
        case NETDEV_UP:
                if (!inetdev_valid_mtu(dev->mtu))
                        break;
                if (dev->flags & IFF_LOOPBACK) {
                        struct in_ifaddr *ifa = inet_alloc_ifa();

                        if (ifa) {
                                INIT_HLIST_NODE(&ifa->hash);
                                ifa->ifa_local =
                                  ifa->ifa_address = htonl(INADDR_LOOPBACK);
                                ifa->ifa_prefixlen = 8;
                                ifa->ifa_mask = inet_make_mask(8);
                                in_dev_hold(in_dev);
                                ifa->ifa_dev = in_dev;
                                ifa->ifa_scope = RT_SCOPE_HOST;
                                memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
                                set_ifa_lifetime(ifa, INFINITY_LIFE_TIME,
                                                 INFINITY_LIFE_TIME);
                                ipv4_devconf_setall(in_dev);
                                neigh_parms_data_state_setall(in_dev->arp_parms);
                                inet_insert_ifa(ifa);
                        }
                }
                ip_mc_up(in_dev);
                /* fall through */
        case NETDEV_CHANGEADDR:
                if (!IN_DEV_ARP_NOTIFY(in_dev))
                        break;
                /* fall through */
        case NETDEV_NOTIFY_PEERS:
                /* Send gratuitous ARP to notify of link change */
                inetdev_send_gratuitous_arp(dev, in_dev);
                break;
        case NETDEV_DOWN:
                ip_mc_down(in_dev);
                break;
        case NETDEV_PRE_TYPE_CHANGE:
                ip_mc_unmap(in_dev);
                break;
        case NETDEV_POST_TYPE_CHANGE:
                ip_mc_remap(in_dev);
                break;
        case NETDEV_CHANGEMTU:
                if (inetdev_valid_mtu(dev->mtu))
                        break;
                /* disable IP when MTU is not enough */
                /* fall through */
        case NETDEV_UNREGISTER:
                inetdev_destroy(in_dev);
                break;
        case NETDEV_CHANGENAME:
                /* Do not notify about label change, this event is
                 * not interesting to applications using netlink.
                 */
                inetdev_changename(dev, in_dev);

                devinet_sysctl_unregister(in_dev);
                devinet_sysctl_register(in_dev);
                break;
        }
out:
        return NOTIFY_DONE;
}

static struct notifier_block ip_netdev_notifier = {
        .notifier_call = inetdev_event,
};

static size_t inet_nlmsg_size(void)
{
        return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
               + nla_total_size(4) /* IFA_ADDRESS */
               + nla_total_size(4) /* IFA_LOCAL */
               + nla_total_size(4) /* IFA_BROADCAST */
               + nla_total_size(IFNAMSIZ) /* IFA_LABEL */
               + nla_total_size(4)  /* IFA_FLAGS */
               + nla_total_size(4)  /* IFA_RT_PRIORITY */
               + nla_total_size(sizeof(struct ifa_cacheinfo)); /* IFA_CACHEINFO */
}

static inline u32 cstamp_delta(unsigned long cstamp)
{
        return (cstamp - INITIAL_JIFFIES) * 100UL / HZ;
}

static int put_cacheinfo(struct sk_buff *skb, unsigned long cstamp,
                         unsigned long tstamp, u32 preferred, u32 valid)
{
        struct ifa_cacheinfo ci;

        ci.cstamp = cstamp_delta(cstamp);
        ci.tstamp = cstamp_delta(tstamp);
        ci.ifa_prefered = preferred;
        ci.ifa_valid = valid;

        return nla_put(skb, IFA_CACHEINFO, sizeof(ci), &ci);
}

static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
                            struct inet_fill_args *args)
{
        struct ifaddrmsg *ifm;
        struct nlmsghdr  *nlh;
        u32 preferred, valid;

        nlh = nlmsg_put(skb, args->portid, args->seq, args->event, sizeof(*ifm),
                        args->flags);
        if (!nlh)
                return -EMSGSIZE;

        ifm = nlmsg_data(nlh);
        ifm->ifa_family = AF_INET;
        ifm->ifa_prefixlen = ifa->ifa_prefixlen;
        ifm->ifa_flags = ifa->ifa_flags;
        ifm->ifa_scope = ifa->ifa_scope;
        ifm->ifa_index = ifa->ifa_dev->dev->ifindex;

        if (args->netnsid >= 0 &&
            nla_put_s32(skb, IFA_TARGET_NETNSID, args->netnsid))
                goto nla_put_failure;

        if (!(ifm->ifa_flags & IFA_F_PERMANENT)) {
                preferred = ifa->ifa_preferred_lft;
                valid = ifa->ifa_valid_lft;
                if (preferred != INFINITY_LIFE_TIME) {
                        long tval = (jiffies - ifa->ifa_tstamp) / HZ;

                        if (preferred > tval)
                                preferred -= tval;
                        else
                                preferred = 0;
                        if (valid != INFINITY_LIFE_TIME) {
                                if (valid > tval)
                                        valid -= tval;
                                else
                                        valid = 0;
                        }
                }
        } else {
                preferred = INFINITY_LIFE_TIME;
                valid = INFINITY_LIFE_TIME;
        }
        if ((ifa->ifa_address &&
             nla_put_in_addr(skb, IFA_ADDRESS, ifa->ifa_address)) ||
            (ifa->ifa_local &&
             nla_put_in_addr(skb, IFA_LOCAL, ifa->ifa_local)) ||
            (ifa->ifa_broadcast &&
             nla_put_in_addr(skb, IFA_BROADCAST, ifa->ifa_broadcast)) ||
            (ifa->ifa_label[0] &&
             nla_put_string(skb, IFA_LABEL, ifa->ifa_label)) ||
            nla_put_u32(skb, IFA_FLAGS, ifa->ifa_flags) ||
            (ifa->ifa_rt_priority &&
             nla_put_u32(skb, IFA_RT_PRIORITY, ifa->ifa_rt_priority)) ||
            put_cacheinfo(skb, ifa->ifa_cstamp, ifa->ifa_tstamp,
                          preferred, valid))
                goto nla_put_failure;

        nlmsg_end(skb, nlh);
        return 0;

nla_put_failure:
        nlmsg_cancel(skb, nlh);
        return -EMSGSIZE;
}

static int inet_valid_dump_ifaddr_req(const struct nlmsghdr *nlh,
                                      struct inet_fill_args *fillargs,
                                      struct net **tgt_net, struct sock *sk,
                                      struct netlink_callback *cb)
{
        struct netlink_ext_ack *extack = cb->extack;
        struct nlattr *tb[IFA_MAX+1];
        struct ifaddrmsg *ifm;
        int err, i;

        if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifm))) {
                NL_SET_ERR_MSG(extack, "ipv4: Invalid header for address dump request");
                return -EINVAL;
        }

        ifm = nlmsg_data(nlh);
        if (ifm->ifa_prefixlen || ifm->ifa_flags || ifm->ifa_scope) {
                NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for address dump request");
                return -EINVAL;
        }

        fillargs->ifindex = ifm->ifa_index;
        if (fillargs->ifindex) {
                cb->answer_flags |= NLM_F_DUMP_FILTERED;
                fillargs->flags |= NLM_F_DUMP_FILTERED;
        }

        err = nlmsg_parse_deprecated_strict(nlh, sizeof(*ifm), tb, IFA_MAX,
                                            ifa_ipv4_policy, extack);
        if (err < 0)
                return err;

        for (i = 0; i <= IFA_MAX; ++i) {
                if (!tb[i])
                        continue;

                if (i == IFA_TARGET_NETNSID) {
                        struct net *net;

                        fillargs->netnsid = nla_get_s32(tb[i]);

                        net = rtnl_get_net_ns_capable(sk, fillargs->netnsid);
                        if (IS_ERR(net)) {
                                fillargs->netnsid = -1;
                                NL_SET_ERR_MSG(extack, "ipv4: Invalid target network namespace id");
                                return PTR_ERR(net);
                        }
                        *tgt_net = net;
                } else {
                        NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in dump request");
                        return -EINVAL;
                }
        }

        return 0;
}

static int in_dev_dump_addr(struct in_device *in_dev, struct sk_buff *skb,
                            struct netlink_callback *cb, int s_ip_idx,
                            struct inet_fill_args *fillargs)
{
        struct in_ifaddr *ifa;
        int ip_idx = 0;
        int err;

        in_dev_for_each_ifa_rtnl(ifa, in_dev) {
                if (ip_idx < s_ip_idx) {
                        ip_idx++;
                        continue;
                }
                err = inet_fill_ifaddr(skb, ifa, fillargs);
                if (err < 0)
                        goto done;

                nl_dump_check_consistent(cb, nlmsg_hdr(skb));
                ip_idx++;
        }
        err = 0;

done:
        cb->args[2] = ip_idx;

        return err;
}

static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
{
        const struct nlmsghdr *nlh = cb->nlh;
        struct inet_fill_args fillargs = {
                .portid = NETLINK_CB(cb->skb).portid,
                .seq = nlh->nlmsg_seq,
                .event = RTM_NEWADDR,
                .flags = NLM_F_MULTI,
                .netnsid = -1,
        };
        struct net *net = sock_net(skb->sk);
        struct net *tgt_net = net;
        int h, s_h;
        int idx, s_idx;
        int s_ip_idx;
        struct net_device *dev;
        struct in_device *in_dev;
        struct hlist_head *head;
        int err = 0;

        s_h = cb->args[0];
        s_idx = idx = cb->args[1];
        s_ip_idx = cb->args[2];

        if (cb->strict_check) {
                err = inet_valid_dump_ifaddr_req(nlh, &fillargs, &tgt_net,
                                                 skb->sk, cb);
                if (err < 0)
                        goto put_tgt_net;

                err = 0;
                if (fillargs.ifindex) {
                        dev = __dev_get_by_index(tgt_net, fillargs.ifindex);
                        if (!dev) {
                                err = -ENODEV;
                                goto put_tgt_net;
                        }

                        in_dev = __in_dev_get_rtnl(dev);
                        if (in_dev) {
                                err = in_dev_dump_addr(in_dev, skb, cb, s_ip_idx,
                                                       &fillargs);
                        }
                        goto put_tgt_net;
                }
        }

        for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
                idx = 0;
                head = &tgt_net->dev_index_head[h];
                rcu_read_lock();
                cb->seq = atomic_read(&tgt_net->ipv4.dev_addr_genid) ^
                          tgt_net->dev_base_seq;
                hlist_for_each_entry_rcu(dev, head, index_hlist) {
                        if (idx < s_idx)
                                goto cont;
                        if (h > s_h || idx > s_idx)
                                s_ip_idx = 0;
                        in_dev = __in_dev_get_rcu(dev);
                        if (!in_dev)
                                goto cont;

                        err = in_dev_dump_addr(in_dev, skb, cb, s_ip_idx,
                                               &fillargs);
                        if (err < 0) {
                                rcu_read_unlock();
                                goto done;
                        }
cont:
                        idx++;
                }
                rcu_read_unlock();
        }

done:
        cb->args[0] = h;
        cb->args[1] = idx;
put_tgt_net:
        if (fillargs.netnsid >= 0)
                put_net(tgt_net);

        return skb->len ? : err;
}

static void rtmsg_ifa(int event, struct in_ifaddr *ifa, struct nlmsghdr *nlh,
                      u32 portid)
{
        struct inet_fill_args fillargs = {
                .portid = portid,
                .seq = nlh ? nlh->nlmsg_seq : 0,
                .event = event,
                .flags = 0,
                .netnsid = -1,
        };
        struct sk_buff *skb;
        int err = -ENOBUFS;
        struct net *net;

        net = dev_net(ifa->ifa_dev->dev);
        skb = nlmsg_new(inet_nlmsg_size(), GFP_KERNEL);
        if (!skb)
                goto errout;

        err = inet_fill_ifaddr(skb, ifa, &fillargs);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet_nlmsg_size() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        rtnl_notify(skb, net, portid, RTNLGRP_IPV4_IFADDR, nlh, GFP_KERNEL);
        return;
errout:
        if (err < 0)
                rtnl_set_sk_err(net, RTNLGRP_IPV4_IFADDR, err);
}

static size_t inet_get_link_af_size(const struct net_device *dev,
                                    u32 ext_filter_mask)
{
        struct in_device *in_dev = rcu_dereference_rtnl(dev->ip_ptr);

        if (!in_dev)
                return 0;

        return nla_total_size(IPV4_DEVCONF_MAX * 4); /* IFLA_INET_CONF */
}

static int inet_fill_link_af(struct sk_buff *skb, const struct net_device *dev,
                             u32 ext_filter_mask)
{
        struct in_device *in_dev = rcu_dereference_rtnl(dev->ip_ptr);
        struct nlattr *nla;
        int i;

        if (!in_dev)
                return -ENODATA;

        nla = nla_reserve(skb, IFLA_INET_CONF, IPV4_DEVCONF_MAX * 4);
        if (!nla)
                return -EMSGSIZE;

        for (i = 0; i < IPV4_DEVCONF_MAX; i++)
                ((u32 *) nla_data(nla))[i] = in_dev->cnf.data[i];

        return 0;
}

static const struct nla_policy inet_af_policy[IFLA_INET_MAX+1] = {
        [IFLA_INET_CONF]        = { .type = NLA_NESTED },
};

static int inet_validate_link_af(const struct net_device *dev,
                                 const struct nlattr *nla)
{
        struct nlattr *a, *tb[IFLA_INET_MAX+1];
        int err, rem;

        if (dev && !__in_dev_get_rcu(dev))
                return -EAFNOSUPPORT;

        err = nla_parse_nested_deprecated(tb, IFLA_INET_MAX, nla,
                                          inet_af_policy, NULL);
        if (err < 0)
                return err;

        if (tb[IFLA_INET_CONF]) {
                nla_for_each_nested(a, tb[IFLA_INET_CONF], rem) {
                        int cfgid = nla_type(a);

                        if (nla_len(a) < 4)
                                return -EINVAL;

                        if (cfgid <= 0 || cfgid > IPV4_DEVCONF_MAX)
                                return -EINVAL;
                }
        }

        return 0;
}

static int inet_set_link_af(struct net_device *dev, const struct nlattr *nla)
{
        struct in_device *in_dev = __in_dev_get_rcu(dev);
        struct nlattr *a, *tb[IFLA_INET_MAX+1];
        int rem;

        if (!in_dev)
                return -EAFNOSUPPORT;

        if (nla_parse_nested_deprecated(tb, IFLA_INET_MAX, nla, NULL, NULL) < 0)
                BUG();

        if (tb[IFLA_INET_CONF]) {
                nla_for_each_nested(a, tb[IFLA_INET_CONF], rem)
                        ipv4_devconf_set(in_dev, nla_type(a), nla_get_u32(a));
        }

        return 0;
}

static int inet_netconf_msgsize_devconf(int type)
{
        int size = NLMSG_ALIGN(sizeof(struct netconfmsg))
                   + nla_total_size(4); /* NETCONFA_IFINDEX */
        bool all = false;

        if (type == NETCONFA_ALL)
                all = true;

        if (all || type == NETCONFA_FORWARDING)
                size += nla_total_size(4);
        if (all || type == NETCONFA_RP_FILTER)
                size += nla_total_size(4);
        if (all || type == NETCONFA_MC_FORWARDING)
                size += nla_total_size(4);
        if (all || type == NETCONFA_BC_FORWARDING)
                size += nla_total_size(4);
        if (all || type == NETCONFA_PROXY_NEIGH)
                size += nla_total_size(4);
        if (all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN)
                size += nla_total_size(4);

        return size;
}

static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
                                     struct ipv4_devconf *devconf, u32 portid,
                                     u32 seq, int event, unsigned int flags,
                                     int type)
{
        struct nlmsghdr  *nlh;
        struct netconfmsg *ncm;
        bool all = false;

        nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct netconfmsg),
                        flags);
        if (!nlh)
                return -EMSGSIZE;

        if (type == NETCONFA_ALL)
                all = true;

        ncm = nlmsg_data(nlh);
        ncm->ncm_family = AF_INET;

        if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
                goto nla_put_failure;

        if (!devconf)
                goto out;

        if ((all || type == NETCONFA_FORWARDING) &&
            nla_put_s32(skb, NETCONFA_FORWARDING,
                        IPV4_DEVCONF(*devconf, FORWARDING)) < 0)
                goto nla_put_failure;
        if ((all || type == NETCONFA_RP_FILTER) &&
            nla_put_s32(skb, NETCONFA_RP_FILTER,
                        IPV4_DEVCONF(*devconf, RP_FILTER)) < 0)
                goto nla_put_failure;
        if ((all || type == NETCONFA_MC_FORWARDING) &&
            nla_put_s32(skb, NETCONFA_MC_FORWARDING,
                        IPV4_DEVCONF(*devconf, MC_FORWARDING)) < 0)
                goto nla_put_failure;
        if ((all || type == NETCONFA_BC_FORWARDING) &&
            nla_put_s32(skb, NETCONFA_BC_FORWARDING,
                        IPV4_DEVCONF(*devconf, BC_FORWARDING)) < 0)
                goto nla_put_failure;
        if ((all || type == NETCONFA_PROXY_NEIGH) &&
            nla_put_s32(skb, NETCONFA_PROXY_NEIGH,
                        IPV4_DEVCONF(*devconf, PROXY_ARP)) < 0)
                goto nla_put_failure;
        if ((all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) &&
            nla_put_s32(skb, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
                        IPV4_DEVCONF(*devconf, IGNORE_ROUTES_WITH_LINKDOWN)) < 0)
                goto nla_put_failure;

out:
        nlmsg_end(skb, nlh);
        return 0;

nla_put_failure:
        nlmsg_cancel(skb, nlh);
        return -EMSGSIZE;
}

void inet_netconf_notify_devconf(struct net *net, int event, int type,
                                 int ifindex, struct ipv4_devconf *devconf)
{
        struct sk_buff *skb;
        int err = -ENOBUFS;

        skb = nlmsg_new(inet_netconf_msgsize_devconf(type), GFP_KERNEL);
        if (!skb)
                goto errout;

        err = inet_netconf_fill_devconf(skb, ifindex, devconf, 0, 0,
                                        event, 0, type);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet_netconf_msgsize_devconf() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        rtnl_notify(skb, net, 0, RTNLGRP_IPV4_NETCONF, NULL, GFP_KERNEL);
        return;
errout:
        if (err < 0)
                rtnl_set_sk_err(net, RTNLGRP_IPV4_NETCONF, err);
}

static const struct nla_policy devconf_ipv4_policy[NETCONFA_MAX+1] = {
        [NETCONFA_IFINDEX]      = { .len = sizeof(int) },
        [NETCONFA_FORWARDING]   = { .len = sizeof(int) },
        [NETCONFA_RP_FILTER]    = { .len = sizeof(int) },
        [NETCONFA_PROXY_NEIGH]  = { .len = sizeof(int) },
        [NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN]  = { .len = sizeof(int) },
};

static int inet_netconf_valid_get_req(struct sk_buff *skb,
                                      const struct nlmsghdr *nlh,
                                      struct nlattr **tb,
                                      struct netlink_ext_ack *extack)
{
        int i, err;

        if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(struct netconfmsg))) {
                NL_SET_ERR_MSG(extack, "ipv4: Invalid header for netconf get request");
                return -EINVAL;
        }

        if (!netlink_strict_get_check(skb))
                return nlmsg_parse_deprecated(nlh, sizeof(struct netconfmsg),
                                              tb, NETCONFA_MAX,
                                              devconf_ipv4_policy, extack);

        err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct netconfmsg),
                                            tb, NETCONFA_MAX,
                                            devconf_ipv4_policy, extack);
        if (err)
                return err;

        for (i = 0; i <= NETCONFA_MAX; i++) {
                if (!tb[i])
                        continue;

                switch (i) {
                case NETCONFA_IFINDEX:
                        break;
                default:
                        NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in netconf get request");
                        return -EINVAL;
                }
        }

        return 0;
}

static int inet_netconf_get_devconf(struct sk_buff *in_skb,
                                    struct nlmsghdr *nlh,
                                    struct netlink_ext_ack *extack)
{
        struct net *net = sock_net(in_skb->sk);
        struct nlattr *tb[NETCONFA_MAX+1];
        struct sk_buff *skb;
        struct ipv4_devconf *devconf;
        struct in_device *in_dev;
        struct net_device *dev;
        int ifindex;
        int err;

        err = inet_netconf_valid_get_req(in_skb, nlh, tb, extack);
        if (err)
                goto errout;

        err = -EINVAL;
        if (!tb[NETCONFA_IFINDEX])
                goto errout;

        ifindex = nla_get_s32(tb[NETCONFA_IFINDEX]);
        switch (ifindex) {
        case NETCONFA_IFINDEX_ALL:
                devconf = net->ipv4.devconf_all;
                break;
        case NETCONFA_IFINDEX_DEFAULT:
                devconf = net->ipv4.devconf_dflt;
                break;
        default:
                dev = __dev_get_by_index(net, ifindex);
                if (!dev)
                        goto errout;
                in_dev = __in_dev_get_rtnl(dev);
                if (!in_dev)
                        goto errout;
                devconf = &in_dev->cnf;
                break;
        }

        err = -ENOBUFS;
        skb = nlmsg_new(inet_netconf_msgsize_devconf(NETCONFA_ALL), GFP_KERNEL);
        if (!skb)
                goto errout;

        err = inet_netconf_fill_devconf(skb, ifindex, devconf,
                                        NETLINK_CB(in_skb).portid,
                                        nlh->nlmsg_seq, RTM_NEWNETCONF, 0,
                                        NETCONFA_ALL);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in inet_netconf_msgsize_devconf() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
errout:
        return err;
}

static int inet_netconf_dump_devconf(struct sk_buff *skb,
                                     struct netlink_callback *cb)
{
        const struct nlmsghdr *nlh = cb->nlh;
        struct net *net = sock_net(skb->sk);
        int h, s_h;
        int idx, s_idx;
        struct net_device *dev;
        struct in_device *in_dev;
        struct hlist_head *head;

        if (cb->strict_check) {
                struct netlink_ext_ack *extack = cb->extack;
                struct netconfmsg *ncm;

                if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ncm))) {
                        NL_SET_ERR_MSG(extack, "ipv4: Invalid header for netconf dump request");
                        return -EINVAL;
                }

                if (nlmsg_attrlen(nlh, sizeof(*ncm))) {
                        NL_SET_ERR_MSG(extack, "ipv4: Invalid data after header in netconf dump request");
                        return -EINVAL;
                }
        }

        s_h = cb->args[0];
        s_idx = idx = cb->args[1];

        for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
                idx = 0;
                head = &net->dev_index_head[h];
                rcu_read_lock();
                cb->seq = atomic_read(&net->ipv4.dev_addr_genid) ^
                          net->dev_base_seq;
                hlist_for_each_entry_rcu(dev, head, index_hlist) {
                        if (idx < s_idx)
                                goto cont;
                        in_dev = __in_dev_get_rcu(dev);
                        if (!in_dev)
                                goto cont;

                        if (inet_netconf_fill_devconf(skb, dev->ifindex,
                                                      &in_dev->cnf,
                                                      NETLINK_CB(cb->skb).portid,
                                                      nlh->nlmsg_seq,
                                                      RTM_NEWNETCONF,
                                                      NLM_F_MULTI,
                                                      NETCONFA_ALL) < 0) {
                                rcu_read_unlock();
                                goto done;
                        }
                        nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont:
                        idx++;
                }
                rcu_read_unlock();
        }
        if (h == NETDEV_HASHENTRIES) {
                if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,
                                              net->ipv4.devconf_all,
                                              NETLINK_CB(cb->skb).portid,
                                              nlh->nlmsg_seq,
                                              RTM_NEWNETCONF, NLM_F_MULTI,
                                              NETCONFA_ALL) < 0)
                        goto done;
                else
                        h++;
        }
        if (h == NETDEV_HASHENTRIES + 1) {
                if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,
                                              net->ipv4.devconf_dflt,
                                              NETLINK_CB(cb->skb).portid,
                                              nlh->nlmsg_seq,
                                              RTM_NEWNETCONF, NLM_F_MULTI,
                                              NETCONFA_ALL) < 0)
                        goto done;
                else
                        h++;
        }
done:
        cb->args[0] = h;
        cb->args[1] = idx;

        return skb->len;
}

#ifdef CONFIG_SYSCTL

static void devinet_copy_dflt_conf(struct net *net, int i)
{
        struct net_device *dev;

        rcu_read_lock();
        for_each_netdev_rcu(net, dev) {
                struct in_device *in_dev;

                in_dev = __in_dev_get_rcu(dev);
                if (in_dev && !test_bit(i, in_dev->cnf.state))
                        in_dev->cnf.data[i] = net->ipv4.devconf_dflt->data[i];
        }
        rcu_read_unlock();
}

/* called with RTNL locked */
static void inet_forward_change(struct net *net)
{
        struct net_device *dev;
        int on = IPV4_DEVCONF_ALL(net, FORWARDING);

        IPV4_DEVCONF_ALL(net, ACCEPT_REDIRECTS) = !on;
        IPV4_DEVCONF_DFLT(net, FORWARDING) = on;
        inet_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                    NETCONFA_FORWARDING,
                                    NETCONFA_IFINDEX_ALL,
                                    net->ipv4.devconf_all);
        inet_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                    NETCONFA_FORWARDING,
                                    NETCONFA_IFINDEX_DEFAULT,
                                    net->ipv4.devconf_dflt);

        for_each_netdev(net, dev) {
                struct in_device *in_dev;

                if (on)
                        dev_disable_lro(dev);

                in_dev = __in_dev_get_rtnl(dev);
                if (in_dev) {
                        IN_DEV_CONF_SET(in_dev, FORWARDING, on);
                        inet_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                    NETCONFA_FORWARDING,
                                                    dev->ifindex, &in_dev->cnf);
                }
        }
}

static int devinet_conf_ifindex(struct net *net, struct ipv4_devconf *cnf)
{
        if (cnf == net->ipv4.devconf_dflt)
                return NETCONFA_IFINDEX_DEFAULT;
        else if (cnf == net->ipv4.devconf_all)
                return NETCONFA_IFINDEX_ALL;
        else {
                struct in_device *idev
                        = container_of(cnf, struct in_device, cnf);
                return idev->dev->ifindex;
        }
}

static int devinet_conf_proc(struct ctl_table *ctl, int write,
                             void __user *buffer,
                             size_t *lenp, loff_t *ppos)
{
        int old_value = *(int *)ctl->data;
        int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
        int new_value = *(int *)ctl->data;

        if (write) {
                struct ipv4_devconf *cnf = ctl->extra1;
                struct net *net = ctl->extra2;
                int i = (int *)ctl->data - cnf->data;
                int ifindex;

                set_bit(i, cnf->state);

                if (cnf == net->ipv4.devconf_dflt)
                        devinet_copy_dflt_conf(net, i);
                if (i == IPV4_DEVCONF_ACCEPT_LOCAL - 1 ||
                    i == IPV4_DEVCONF_ROUTE_LOCALNET - 1)
                        if ((new_value == 0) && (old_value != 0))
                                rt_cache_flush(net);

                if (i == IPV4_DEVCONF_BC_FORWARDING - 1 &&
                    new_value != old_value)
                        rt_cache_flush(net);

                if (i == IPV4_DEVCONF_RP_FILTER - 1 &&
                    new_value != old_value) {
                        ifindex = devinet_conf_ifindex(net, cnf);
                        inet_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                    NETCONFA_RP_FILTER,
                                                    ifindex, cnf);
                }
                if (i == IPV4_DEVCONF_PROXY_ARP - 1 &&
                    new_value != old_value) {
                        ifindex = devinet_conf_ifindex(net, cnf);
                        inet_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                    NETCONFA_PROXY_NEIGH,
                                                    ifindex, cnf);
                }
                if (i == IPV4_DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN - 1 &&
                    new_value != old_value) {
                        ifindex = devinet_conf_ifindex(net, cnf);
                        inet_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                    NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
                                                    ifindex, cnf);
                }
        }

        return ret;
}

static int devinet_sysctl_forward(struct ctl_table *ctl, int write,
                                  void __user *buffer,
                                  size_t *lenp, loff_t *ppos)
{
        int *valp = ctl->data;
        int val = *valp;
        loff_t pos = *ppos;
        int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);

        if (write && *valp != val) {
                struct net *net = ctl->extra2;

                if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) {
                        if (!rtnl_trylock()) {
                                /* Restore the original values before restarting */
                                *valp = val;
                                *ppos = pos;
                                return restart_syscall();
                        }
                        if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING)) {
                                inet_forward_change(net);
                        } else {
                                struct ipv4_devconf *cnf = ctl->extra1;
                                struct in_device *idev =
                                        container_of(cnf, struct in_device, cnf);
                                if (*valp)
                                        dev_disable_lro(idev->dev);
                                inet_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                            NETCONFA_FORWARDING,
                                                            idev->dev->ifindex,
                                                            cnf);
                        }
                        rtnl_unlock();
                        rt_cache_flush(net);
                } else
                        inet_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                    NETCONFA_FORWARDING,
                                                    NETCONFA_IFINDEX_DEFAULT,
                                                    net->ipv4.devconf_dflt);
        }

        return ret;
}

static int ipv4_doint_and_flush(struct ctl_table *ctl, int write,
                                void __user *buffer,
                                size_t *lenp, loff_t *ppos)
{
        int *valp = ctl->data;
        int val = *valp;
        int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
        struct net *net = ctl->extra2;

        if (write && *valp != val)
                rt_cache_flush(net);

        return ret;
}

#define DEVINET_SYSCTL_ENTRY(attr, name, mval, proc) \
        { \
                .procname       = name, \
                .data           = ipv4_devconf.data + \
                                  IPV4_DEVCONF_ ## attr - 1, \
                .maxlen         = sizeof(int), \
                .mode           = mval, \
                .proc_handler   = proc, \
                .extra1         = &ipv4_devconf, \
        }

#define DEVINET_SYSCTL_RW_ENTRY(attr, name) \
        DEVINET_SYSCTL_ENTRY(attr, name, 0644, devinet_conf_proc)

#define DEVINET_SYSCTL_RO_ENTRY(attr, name) \
        DEVINET_SYSCTL_ENTRY(attr, name, 0444, devinet_conf_proc)

#define DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, proc) \
        DEVINET_SYSCTL_ENTRY(attr, name, 0644, proc)

#define DEVINET_SYSCTL_FLUSHING_ENTRY(attr, name) \
        DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, ipv4_doint_and_flush)

static struct devinet_sysctl_table {
        struct ctl_table_header *sysctl_header;
        struct ctl_table devinet_vars[__IPV4_DEVCONF_MAX];
} devinet_sysctl = {
        .devinet_vars = {
                DEVINET_SYSCTL_COMPLEX_ENTRY(FORWARDING, "forwarding",
                                             devinet_sysctl_forward),
                DEVINET_SYSCTL_RO_ENTRY(MC_FORWARDING, "mc_forwarding"),
                DEVINET_SYSCTL_RW_ENTRY(BC_FORWARDING, "bc_forwarding"),

                DEVINET_SYSCTL_RW_ENTRY(ACCEPT_REDIRECTS, "accept_redirects"),
                DEVINET_SYSCTL_RW_ENTRY(SECURE_REDIRECTS, "secure_redirects"),
                DEVINET_SYSCTL_RW_ENTRY(SHARED_MEDIA, "shared_media"),
                DEVINET_SYSCTL_RW_ENTRY(RP_FILTER, "rp_filter"),
                DEVINET_SYSCTL_RW_ENTRY(SEND_REDIRECTS, "send_redirects"),
                DEVINET_SYSCTL_RW_ENTRY(ACCEPT_SOURCE_ROUTE,
                                        "accept_source_route"),
                DEVINET_SYSCTL_RW_ENTRY(ACCEPT_LOCAL, "accept_local"),
                DEVINET_SYSCTL_RW_ENTRY(SRC_VMARK, "src_valid_mark"),
                DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP, "proxy_arp"),
                DEVINET_SYSCTL_RW_ENTRY(MEDIUM_ID, "medium_id"),
                DEVINET_SYSCTL_RW_ENTRY(BOOTP_RELAY, "bootp_relay"),
                DEVINET_SYSCTL_RW_ENTRY(LOG_MARTIANS, "log_martians"),
                DEVINET_SYSCTL_RW_ENTRY(TAG, "tag"),
                DEVINET_SYSCTL_RW_ENTRY(ARPFILTER, "arp_filter"),
                DEVINET_SYSCTL_RW_ENTRY(ARP_ANNOUNCE, "arp_announce"),
                DEVINET_SYSCTL_RW_ENTRY(ARP_IGNORE, "arp_ignore"),
                DEVINET_SYSCTL_RW_ENTRY(ARP_ACCEPT, "arp_accept"),
                DEVINET_SYSCTL_RW_ENTRY(ARP_NOTIFY, "arp_notify"),
                DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP_PVLAN, "proxy_arp_pvlan"),
                DEVINET_SYSCTL_RW_ENTRY(FORCE_IGMP_VERSION,
                                        "force_igmp_version"),
                DEVINET_SYSCTL_RW_ENTRY(IGMPV2_UNSOLICITED_REPORT_INTERVAL,
                                        "igmpv2_unsolicited_report_interval"),
                DEVINET_SYSCTL_RW_ENTRY(IGMPV3_UNSOLICITED_REPORT_INTERVAL,
                                        "igmpv3_unsolicited_report_interval"),
                DEVINET_SYSCTL_RW_ENTRY(IGNORE_ROUTES_WITH_LINKDOWN,
                                        "ignore_routes_with_linkdown"),
                DEVINET_SYSCTL_RW_ENTRY(DROP_GRATUITOUS_ARP,
                                        "drop_gratuitous_arp"),

                DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"),
                DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"),
                DEVINET_SYSCTL_FLUSHING_ENTRY(PROMOTE_SECONDARIES,
                                              "promote_secondaries"),
                DEVINET_SYSCTL_FLUSHING_ENTRY(ROUTE_LOCALNET,
                                              "route_localnet"),
                DEVINET_SYSCTL_FLUSHING_ENTRY(DROP_UNICAST_IN_L2_MULTICAST,
                                              "drop_unicast_in_l2_multicast"),
        },
};

static int __devinet_sysctl_register(struct net *net, char *dev_name,
                                     int ifindex, struct ipv4_devconf *p)
{
        int i;
        struct devinet_sysctl_table *t;
        char path[sizeof("net/ipv4/conf/") + IFNAMSIZ];

        t = kmemdup(&devinet_sysctl, sizeof(*t), GFP_KERNEL);
        if (!t)
                goto out;

        for (i = 0; i < ARRAY_SIZE(t->devinet_vars) - 1; i++) {
                t->devinet_vars[i].data += (char *)p - (char *)&ipv4_devconf;
                t->devinet_vars[i].extra1 = p;
                t->devinet_vars[i].extra2 = net;
        }

        snprintf(path, sizeof(path), "net/ipv4/conf/%s", dev_name);

        t->sysctl_header = register_net_sysctl(net, path, t->devinet_vars);
        if (!t->sysctl_header)
                goto free;

        p->sysctl = t;

        inet_netconf_notify_devconf(net, RTM_NEWNETCONF, NETCONFA_ALL,
                                    ifindex, p);
        return 0;

free:
        kfree(t);
out:
        return -ENOBUFS;
}

static void __devinet_sysctl_unregister(struct net *net,
                                        struct ipv4_devconf *cnf, int ifindex)
{
        struct devinet_sysctl_table *t = cnf->sysctl;

        if (t) {
                cnf->sysctl = NULL;
                unregister_net_sysctl_table(t->sysctl_header);
                kfree(t);
        }

        inet_netconf_notify_devconf(net, RTM_DELNETCONF, 0, ifindex, NULL);
}

static int devinet_sysctl_register(struct in_device *idev)
{
        int err;

        if (!sysctl_dev_name_is_allowed(idev->dev->name))
                return -EINVAL;

        err = neigh_sysctl_register(idev->dev, idev->arp_parms, NULL);
        if (err)
                return err;
        err = __devinet_sysctl_register(dev_net(idev->dev), idev->dev->name,
                                        idev->dev->ifindex, &idev->cnf);
        if (err)
                neigh_sysctl_unregister(idev->arp_parms);
        return err;
}

static void devinet_sysctl_unregister(struct in_device *idev)
{
        struct net *net = dev_net(idev->dev);

        __devinet_sysctl_unregister(net, &idev->cnf, idev->dev->ifindex);
        neigh_sysctl_unregister(idev->arp_parms);
}

static struct ctl_table ctl_forward_entry[] = {
        {
                .procname       = "ip_forward",
                .data           = &ipv4_devconf.data[
                                        IPV4_DEVCONF_FORWARDING - 1],
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = devinet_sysctl_forward,
                .extra1         = &ipv4_devconf,
                .extra2         = &init_net,
        },
        { },
};
#endif

static __net_init int devinet_init_net(struct net *net)
{
        int err;
        struct ipv4_devconf *all, *dflt;
#ifdef CONFIG_SYSCTL
        struct ctl_table *tbl;
        struct ctl_table_header *forw_hdr;
#endif

        err = -ENOMEM;
        all = kmemdup(&ipv4_devconf, sizeof(ipv4_devconf), GFP_KERNEL);
        if (!all)
                goto err_alloc_all;

        dflt = kmemdup(&ipv4_devconf_dflt, sizeof(ipv4_devconf_dflt), GFP_KERNEL);
        if (!dflt)
                goto err_alloc_dflt;

#ifdef CONFIG_SYSCTL
        tbl = kmemdup(ctl_forward_entry, sizeof(ctl_forward_entry), GFP_KERNEL);
        if (!tbl)
                goto err_alloc_ctl;

        tbl[0].data = &all->data[IPV4_DEVCONF_FORWARDING - 1];
        tbl[0].extra1 = all;
        tbl[0].extra2 = net;
#endif

        if ((!IS_ENABLED(CONFIG_SYSCTL) ||
             sysctl_devconf_inherit_init_net != 2) &&
            !net_eq(net, &init_net)) {
                memcpy(all, init_net.ipv4.devconf_all, sizeof(ipv4_devconf));
                memcpy(dflt, init_net.ipv4.devconf_dflt, sizeof(ipv4_devconf_dflt));
        }

#ifdef CONFIG_SYSCTL
        err = __devinet_sysctl_register(net, "all", NETCONFA_IFINDEX_ALL, all);
        if (err < 0)
                goto err_reg_all;

        err = __devinet_sysctl_register(net, "default",
                                        NETCONFA_IFINDEX_DEFAULT, dflt);
        if (err < 0)
                goto err_reg_dflt;

        err = -ENOMEM;
        forw_hdr = register_net_sysctl(net, "net/ipv4", tbl);
        if (!forw_hdr)
                goto err_reg_ctl;
        net->ipv4.forw_hdr = forw_hdr;
#endif

        net->ipv4.devconf_all = all;
        net->ipv4.devconf_dflt = dflt;
        return 0;

#ifdef CONFIG_SYSCTL
err_reg_ctl:
        __devinet_sysctl_unregister(net, dflt, NETCONFA_IFINDEX_DEFAULT);
err_reg_dflt:
        __devinet_sysctl_unregister(net, all, NETCONFA_IFINDEX_ALL);
err_reg_all:
        kfree(tbl);
err_alloc_ctl:
#endif
        kfree(dflt);
err_alloc_dflt:
        kfree(all);
err_alloc_all:
        return err;
}

static __net_exit void devinet_exit_net(struct net *net)
{
#ifdef CONFIG_SYSCTL
        struct ctl_table *tbl;

        tbl = net->ipv4.forw_hdr->ctl_table_arg;
        unregister_net_sysctl_table(net->ipv4.forw_hdr);
        __devinet_sysctl_unregister(net, net->ipv4.devconf_dflt,
                                    NETCONFA_IFINDEX_DEFAULT);
        __devinet_sysctl_unregister(net, net->ipv4.devconf_all,
                                    NETCONFA_IFINDEX_ALL);
        kfree(tbl);
#endif
        kfree(net->ipv4.devconf_dflt);
        kfree(net->ipv4.devconf_all);
}

static __net_initdata struct pernet_operations devinet_ops = {
        .init = devinet_init_net,
        .exit = devinet_exit_net,
};

static struct rtnl_af_ops inet_af_ops __read_mostly = {
        .family           = AF_INET,
        .fill_link_af     = inet_fill_link_af,
        .get_link_af_size = inet_get_link_af_size,
        .validate_link_af = inet_validate_link_af,
        .set_link_af      = inet_set_link_af,
};

void __init devinet_init(void)
{
        int i;

        for (i = 0; i < IN4_ADDR_HSIZE; i++)
                INIT_HLIST_HEAD(&inet_addr_lst[i]);

        register_pernet_subsys(&devinet_ops);

        register_gifconf(PF_INET, inet_gifconf);
        register_netdevice_notifier(&ip_netdev_notifier);

        queue_delayed_work(system_power_efficient_wq, &check_lifetime_work, 0);

        rtnl_af_register(&inet_af_ops);

        rtnl_register(PF_INET, RTM_NEWADDR, inet_rtm_newaddr, NULL, 0);
        rtnl_register(PF_INET, RTM_DELADDR, inet_rtm_deladdr, NULL, 0);
        rtnl_register(PF_INET, RTM_GETADDR, NULL, inet_dump_ifaddr, 0);
        rtnl_register(PF_INET, RTM_GETNETCONF, inet_netconf_get_devconf,
                      inet_netconf_dump_devconf, 0);
}