Hello, On Wed, 8 Jul 2020, Andrew Sy Kim wrote: > 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 <kim.andrewsy@xxxxxxxxx> > Looks good to me, thanks! There is one empty line here that can be removed before applying the patch. Also, post any future patches with version tag, eg. PATCHv2 net-next, etc. For IPVS, "ipvs:" prefix should be enough. Signed-off-by: Julian Anastasov <ja@xxxxxx> > --- > This patch was applied on top of Julian's patch "ipvs: allow > connection reuse for unconfirmed conntrack": > https://marc.info/?l=netfilter-devel&m=159361668110823&w=2 > > include/net/ip_vs.h | 29 ++++++++++++++++++++ > net/netfilter/ipvs/ip_vs_conn.c | 39 +++++++++++++++++++++++++++ > net/netfilter/ipvs/ip_vs_core.c | 47 ++++++++++++++------------------- > net/netfilter/ipvs/ip_vs_ctl.c | 22 +++++++++++++++ > 4 files changed, 110 insertions(+), 27 deletions(-) > > diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h > index 011f407b76fe..91a9e1d590a6 100644 > --- a/include/net/ip_vs.h > +++ b/include/net/ip_vs.h > @@ -14,6 +14,7 @@ > #include <linux/spinlock.h> /* for struct rwlock_t */ > #include <linux/atomic.h> /* for struct atomic_t */ > #include <linux/refcount.h> /* for struct refcount_t */ > +#include <linux/workqueue.h> > > #include <linux/compiler.h> > #include <linux/timer.h> > @@ -886,6 +887,8 @@ struct netns_ipvs { > atomic_t conn_out_counter; > > #ifdef CONFIG_SYSCTL > + /* delayed work for expiring no dest connections */ > + struct delayed_work expire_nodest_conn_work; > /* 1/rate drop and drop-entry variables */ > struct delayed_work defense_work; /* Work handler */ > int drop_rate; > @@ -1051,6 +1054,11 @@ static inline int sysctl_conn_reuse_mode(struct netns_ipvs *ipvs) > return ipvs->sysctl_conn_reuse_mode; > } > > +static inline int sysctl_expire_nodest_conn(struct netns_ipvs *ipvs) > +{ > + return ipvs->sysctl_expire_nodest_conn; > +} > + > static inline int sysctl_schedule_icmp(struct netns_ipvs *ipvs) > { > return ipvs->sysctl_schedule_icmp; > @@ -1138,6 +1146,11 @@ static inline int sysctl_conn_reuse_mode(struct netns_ipvs *ipvs) > return 1; > } > > +static inline int sysctl_expire_nodest_conn(struct netns_ipvs *ipvs) > +{ > + return 0; > +} > + > static inline int sysctl_schedule_icmp(struct netns_ipvs *ipvs) > { > return 0; > @@ -1507,6 +1520,22 @@ static inline int ip_vs_todrop(struct netns_ipvs *ipvs) > static inline int ip_vs_todrop(struct netns_ipvs *ipvs) { return 0; } > #endif > > +#ifdef CONFIG_SYSCTL > +/* Enqueue delayed work for expiring no dest connections > + * Only run when sysctl_expire_nodest=1 > + */ > +static inline void ip_vs_enqueue_expire_nodest_conns(struct netns_ipvs *ipvs) > +{ > + if (sysctl_expire_nodest_conn(ipvs)) > + queue_delayed_work(system_long_wq, > + &ipvs->expire_nodest_conn_work, 1); > +} > + > +void ip_vs_expire_nodest_conn_flush(struct netns_ipvs *ipvs); > +#else > +static inline void ip_vs_enqueue_expire_nodest_conns(struct netns_ipvs) {} > +#endif > + > #define IP_VS_DFWD_METHOD(dest) (atomic_read(&(dest)->conn_flags) & \ > IP_VS_CONN_F_FWD_MASK) > > diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c > index b3921ae92740..a5e9b2d55e57 100644 > --- a/net/netfilter/ipvs/ip_vs_conn.c > +++ b/net/netfilter/ipvs/ip_vs_conn.c > @@ -1389,6 +1389,45 @@ static void ip_vs_conn_flush(struct netns_ipvs *ipvs) > 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) > + return; > + } > + 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); > -- > 2.20.1 Regards -- Julian Anastasov <ja@xxxxxx>
