From 35dfb013149f74c2be1ff9c78f14e6a3cd1539d1 Mon Sep 17 00:00:00 2001 From: Andrew Sy Kim Date: Wed, 8 Jul 2020 12:16:38 -0400 Subject: ipvs: queue delayed work to expire no destination connections if expire_nodest_conn=1 When expire_nodest_conn=1 and a destination is deleted, IPVS does not expire the existing connections until the next matching incoming packet. If there are many connection entries from a single client to a single destination, many packets may get dropped before all the connections are expired (more likely with lots of UDP traffic). An optimization can be made where upon deletion of a destination, IPVS queues up delayed work to immediately expire any connections with a deleted destination. This ensures any reused source ports from a client (within the IPVS timeouts) are scheduled to new real servers instead of silently dropped. Signed-off-by: Andrew Sy Kim Signed-off-by: Julian Anastasov Signed-off-by: Pablo Neira Ayuso --- net/netfilter/ipvs/ip_vs_conn.c | 39 ++++++++++++++++++++++++++++++++++ net/netfilter/ipvs/ip_vs_core.c | 47 ++++++++++++++++++----------------------- net/netfilter/ipvs/ip_vs_ctl.c | 22 +++++++++++++++++++ 3 files changed, 81 insertions(+), 27 deletions(-) (limited to 'net/netfilter/ipvs') diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c index b3921ae92740..a90b8eac16ac 100644 --- a/net/netfilter/ipvs/ip_vs_conn.c +++ b/net/netfilter/ipvs/ip_vs_conn.c @@ -1389,6 +1389,45 @@ flush_again: goto flush_again; } } + +#ifdef CONFIG_SYSCTL +void ip_vs_expire_nodest_conn_flush(struct netns_ipvs *ipvs) +{ + int idx; + struct ip_vs_conn *cp, *cp_c; + struct ip_vs_dest *dest; + + rcu_read_lock(); + for (idx = 0; idx < ip_vs_conn_tab_size; idx++) { + hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) { + if (cp->ipvs != ipvs) + continue; + + dest = cp->dest; + if (!dest || (dest->flags & IP_VS_DEST_F_AVAILABLE)) + continue; + + if (atomic_read(&cp->n_control)) + continue; + + cp_c = cp->control; + IP_VS_DBG(4, "del connection\n"); + ip_vs_conn_del(cp); + if (cp_c && !atomic_read(&cp_c->n_control)) { + IP_VS_DBG(4, "del controlling connection\n"); + ip_vs_conn_del(cp_c); + } + } + cond_resched_rcu(); + + /* netns clean up started, abort delayed work */ + if (!ipvs->enable) + break; + } + rcu_read_unlock(); +} +#endif + /* * per netns init and exit */ diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c index b4a6b7662f3f..e3668a6e54e4 100644 --- a/net/netfilter/ipvs/ip_vs_core.c +++ b/net/netfilter/ipvs/ip_vs_core.c @@ -694,16 +694,10 @@ static int sysctl_nat_icmp_send(struct netns_ipvs *ipvs) return ipvs->sysctl_nat_icmp_send; } -static int sysctl_expire_nodest_conn(struct netns_ipvs *ipvs) -{ - return ipvs->sysctl_expire_nodest_conn; -} - #else static int sysctl_snat_reroute(struct netns_ipvs *ipvs) { return 0; } static int sysctl_nat_icmp_send(struct netns_ipvs *ipvs) { return 0; } -static int sysctl_expire_nodest_conn(struct netns_ipvs *ipvs) { return 0; } #endif @@ -2097,36 +2091,35 @@ ip_vs_in(struct netns_ipvs *ipvs, unsigned int hooknum, struct sk_buff *skb, int } } - if (unlikely(!cp)) { - int v; - - if (!ip_vs_try_to_schedule(ipvs, af, skb, pd, &v, &cp, &iph)) - return v; - } - - IP_VS_DBG_PKT(11, af, pp, skb, iph.off, "Incoming packet"); - /* Check the server status */ - if (cp->dest && !(cp->dest->flags & IP_VS_DEST_F_AVAILABLE)) { + if (cp && cp->dest && !(cp->dest->flags & IP_VS_DEST_F_AVAILABLE)) { /* the destination server is not available */ + if (sysctl_expire_nodest_conn(ipvs)) { + bool old_ct = ip_vs_conn_uses_old_conntrack(cp, skb); - __u32 flags = cp->flags; - - /* when timer already started, silently drop the packet.*/ - if (timer_pending(&cp->timer)) - __ip_vs_conn_put(cp); - else - ip_vs_conn_put(cp); + if (!old_ct) + cp->flags &= ~IP_VS_CONN_F_NFCT; - if (sysctl_expire_nodest_conn(ipvs) && - !(flags & IP_VS_CONN_F_ONE_PACKET)) { - /* try to expire the connection immediately */ ip_vs_conn_expire_now(cp); + __ip_vs_conn_put(cp); + if (old_ct) + return NF_DROP; + cp = NULL; + } else { + __ip_vs_conn_put(cp); + return NF_DROP; } + } - return NF_DROP; + if (unlikely(!cp)) { + int v; + + if (!ip_vs_try_to_schedule(ipvs, af, skb, pd, &v, &cp, &iph)) + return v; } + IP_VS_DBG_PKT(11, af, pp, skb, iph.off, "Incoming packet"); + ip_vs_in_stats(cp, skb); ip_vs_set_state(cp, IP_VS_DIR_INPUT, skb, pd); if (cp->packet_xmit) diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c index 4af83f466dfc..f984d2c881ff 100644 --- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -210,6 +210,17 @@ static void update_defense_level(struct netns_ipvs *ipvs) local_bh_enable(); } +/* Handler for delayed work for expiring no + * destination connections + */ +static void expire_nodest_conn_handler(struct work_struct *work) +{ + struct netns_ipvs *ipvs; + + ipvs = container_of(work, struct netns_ipvs, + expire_nodest_conn_work.work); + ip_vs_expire_nodest_conn_flush(ipvs); +} /* * Timer for checking the defense @@ -1164,6 +1175,12 @@ static void __ip_vs_del_dest(struct netns_ipvs *ipvs, struct ip_vs_dest *dest, list_add(&dest->t_list, &ipvs->dest_trash); dest->idle_start = 0; spin_unlock_bh(&ipvs->dest_trash_lock); + + /* Queue up delayed work to expire all no destination connections. + * No-op when CONFIG_SYSCTL is disabled. + */ + if (!cleanup) + ip_vs_enqueue_expire_nodest_conns(ipvs); } @@ -4086,6 +4103,10 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs) queue_delayed_work(system_long_wq, &ipvs->defense_work, DEFENSE_TIMER_PERIOD); + /* Init delayed work for expiring no dest conn */ + INIT_DELAYED_WORK(&ipvs->expire_nodest_conn_work, + expire_nodest_conn_handler); + return 0; } @@ -4093,6 +4114,7 @@ static void __net_exit ip_vs_control_net_cleanup_sysctl(struct netns_ipvs *ipvs) { struct net *net = ipvs->net; + cancel_delayed_work_sync(&ipvs->expire_nodest_conn_work); cancel_delayed_work_sync(&ipvs->defense_work); cancel_work_sync(&ipvs->defense_work.work); unregister_net_sysctl_table(ipvs->sysctl_hdr); -- cgit v1.2.3-58-ga151