ipv4: Namespacify IPv4 address GC.

Each IPv4 address could have a lifetime, which is useful for DHCP,
and GC is periodically executed as check_lifetime_work.

check_lifetime() does the actual GC under RTNL.

  1. Acquire RTNL
  2. Iterate inet_addr_lst
  3. Remove IPv4 address if expired
  4. Release RTNL

Namespacifying the GC is required for per-netns RTNL, but using the
per-netns hash table will shorten the time on the hash bucket iteration
under RTNL.

Let's add per-netns GC work and use the per-netns hash table.

Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20241008172906.1326-4-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 29eba2eaaa26d13f0d15c6d20ee716033e81985d..66a4cffc44ee27cb32a46c319345611262735ea3 100644 (file)
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -271,5 +271,6 @@ struct netns_ipv4 {
        atomic_t        rt_genid;
        siphash_key_t   ip_id_key;
        struct hlist_head       *inet_addr_lst;
+       struct delayed_work     addr_chk_work;
 };
 #endif

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index cf47b5ac061f91eb846abf1a83b9a94427cde46e..ac245944e89e40ea16f88b08f27438d4d9c247e8 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -486,15 +486,12 @@ static void inet_del_ifa(struct in_device *in_dev,
        __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 net *net = dev_net(in_dev->dev);
        struct in_validator_info ivi;
        struct in_ifaddr *ifa1;
        int ret;
@@ -563,8 +560,8 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
 
        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);
+       cancel_delayed_work(&net->ipv4.addr_chk_work);
+       queue_delayed_work(system_power_efficient_wq, &net->ipv4.addr_chk_work, 0);
 
        /* Send message first, then call notifier.
           Notifier will trigger FIB update, so that
@@ -710,16 +707,19 @@ static void check_lifetime(struct work_struct *work)
        unsigned long now, next, next_sec, next_sched;
        struct in_ifaddr *ifa;
        struct hlist_node *n;
+       struct net *net;
        int i;
 
+       net = container_of(to_delayed_work(work), struct net, ipv4.addr_chk_work);
        now = jiffies;
        next = round_jiffies_up(now + ADDR_CHECK_FREQUENCY);
 
        for (i = 0; i < IN4_ADDR_HSIZE; i++) {
+               struct hlist_head *head = &net->ipv4.inet_addr_lst[i];
                bool change_needed = false;
 
                rcu_read_lock();
-               hlist_for_each_entry_rcu(ifa, &inet_addr_lst[i], hash) {
+               hlist_for_each_entry_rcu(ifa, head, addr_lst) {
                        unsigned long age, tstamp;
                        u32 preferred_lft;
                        u32 valid_lft;
@@ -757,7 +757,7 @@ static void check_lifetime(struct work_struct *work)
                if (!change_needed)
                        continue;
                rtnl_lock();
-               hlist_for_each_entry_safe(ifa, n, &inet_addr_lst[i], hash) {
+               hlist_for_each_entry_safe(ifa, n, head, addr_lst) {
                        unsigned long age;
 
                        if (ifa->ifa_flags & IFA_F_PERMANENT)
@@ -806,8 +806,8 @@ static void check_lifetime(struct work_struct *work)
        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);
+       queue_delayed_work(system_power_efficient_wq, &net->ipv4.addr_chk_work,
+                          next_sched - now);
 }
 
 static void set_ifa_lifetime(struct in_ifaddr *ifa, __u32 valid_lft,
@@ -1004,9 +1004,9 @@ static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
                ifa->ifa_proto = new_proto;
 
                set_ifa_lifetime(ifa, valid_lft, prefered_lft);
-               cancel_delayed_work(&check_lifetime_work);
+               cancel_delayed_work(&net->ipv4.addr_chk_work);
                queue_delayed_work(system_power_efficient_wq,
-                               &check_lifetime_work, 0);
+                                  &net->ipv4.addr_chk_work, 0);
                rtmsg_ifa(RTM_NEWADDR, ifa, nlh, NETLINK_CB(skb).portid);
        }
        return 0;
@@ -2743,6 +2743,8 @@ static __net_init int devinet_init_net(struct net *net)
        for (i = 0; i < IN4_ADDR_HSIZE; i++)
                INIT_HLIST_HEAD(&net->ipv4.inet_addr_lst[i]);
 
+       INIT_DEFERRABLE_WORK(&net->ipv4.addr_chk_work, check_lifetime);
+
        net->ipv4.devconf_all = all;
        net->ipv4.devconf_dflt = dflt;
        return 0;
@@ -2769,7 +2771,11 @@ static __net_exit void devinet_exit_net(struct net *net)
 {
 #ifdef CONFIG_SYSCTL
        const struct ctl_table *tbl;
+#endif
+
+       cancel_delayed_work_sync(&net->ipv4.addr_chk_work);
 
+#ifdef CONFIG_SYSCTL
        tbl = net->ipv4.forw_hdr->ctl_table_arg;
        unregister_net_sysctl_table(net->ipv4.forw_hdr);
        __devinet_sysctl_unregister(net, net->ipv4.devconf_dflt,
@@ -2806,8 +2812,6 @@ void __init devinet_init(void)
        register_pernet_subsys(&devinet_ops);
        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);