linux/net/netfilter/ipvs
Julian Anastasov f719e3754e ipvs: drop first packet to redirect conntrack
Jiri Bohac is reporting for a problem where the attempt
to reschedule existing connection to another real server
needs proper redirect for the conntrack used by the IPVS
connection. For example, when IPVS connection is created
to NAT-ed real server we alter the reply direction of
conntrack. If we later decide to select different real
server we can not alter again the conntrack. And if we
expire the old connection, the new connection is left
without conntrack.

So, the only way to redirect both the IPVS connection and
the Netfilter's conntrack is to drop the SYN packet that
hits existing connection, to wait for the next jiffie
to expire the old connection and its conntrack and to rely
on client's retransmission to create new connection as
usually.

Jiri Bohac provided a fix that drops all SYNs on rescheduling,
I extended his patch to do such drops only for connections
that use conntrack. Here is the original report from Jiri Bohac:

Since commit dc7b3eb900 ("ipvs: Fix reuse connection if real server
is dead"), new connections to dead servers are redistributed
immediately to new servers.  The old connection is expired using
ip_vs_conn_expire_now() which sets the connection timer to expire
immediately.

However, before the timer callback, ip_vs_conn_expire(), is run
to clean the connection's conntrack entry, the new redistributed
connection may already be established and its conntrack removed
instead.

Fix this by dropping the first packet of the new connection
instead, like we do when the destination server is not available.
The timer will have deleted the old conntrack entry long before
the first packet of the new connection is retransmitted.

Fixes: dc7b3eb900 ("ipvs: Fix reuse connection if real server is dead")
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
2016-03-07 11:53:30 +09:00
..
ip_vs_app.c ipvs: Pass ipvs not net into ip_vs_app_net_init and ip_vs_app_net_cleanup 2015-09-24 09:34:40 +09:00
ip_vs_conn.c ipvs: Remove possibly unused variables from ip_vs_conn_net_{init,cleanup} 2015-10-07 10:12:00 +09:00
ip_vs_core.c ipvs: drop first packet to redirect conntrack 2016-03-07 11:53:30 +09:00
ip_vs_ctl.c ipvs: Remove skb_sknet 2015-09-24 09:34:43 +09:00
ip_vs_dh.c ipvs: use correct address family in scheduler logs 2014-09-18 08:59:23 +09:00
ip_vs_est.c ipvs: Pass ipvs not net to ip_vs_estimator_net_init and ip_vs_estimator_cleanup 2015-09-24 09:34:39 +09:00
ip_vs_fo.c ipvs: use correct address family in scheduler logs 2014-09-18 08:59:23 +09:00
ip_vs_ftp.c ipvs: Remove net argument from ip_vs_tcp_conn_listen 2015-09-24 09:34:43 +09:00
ip_vs_lblc.c ipvs: Store ipvs not net in struct ip_vs_service 2015-09-24 09:34:33 +09:00
ip_vs_lblcr.c ipvs: Store ipvs not net in struct ip_vs_service 2015-09-24 09:34:33 +09:00
ip_vs_lc.c ipvs: use correct address family in scheduler logs 2014-09-18 08:59:23 +09:00
ip_vs_nfct.c ipvs: Pass ipvs not net to ip_vs_fill_conn 2015-09-24 09:34:33 +09:00
ip_vs_nq.c ipvs: use correct address family in scheduler logs 2014-09-18 08:59:23 +09:00
ip_vs_ovf.c ipvs: Add ovf scheduler 2015-08-21 09:08:39 -07:00
ip_vs_pe_sip.c ipvs: handle ip_vs_fill_iph_skb_off failure 2016-03-07 11:53:28 +09:00
ip_vs_pe.c netfilter: Deletion of unnecessary checks before two function calls 2014-11-20 13:08:43 +01:00
ip_vs_proto_ah_esp.c ipvs: Pass ipvs into .conn_schedule and ip_vs_try_to_schedule 2015-09-24 09:34:41 +09:00
ip_vs_proto_sctp.c sctp: Rename NETIF_F_SCTP_CSUM to NETIF_F_SCTP_CRC 2015-12-15 16:49:58 -05:00
ip_vs_proto_tcp.c ipvs: Remove net argument from ip_vs_tcp_conn_listen 2015-09-24 09:34:43 +09:00
ip_vs_proto_udp.c ipvs: Pass ipvs into .conn_schedule and ip_vs_try_to_schedule 2015-09-24 09:34:41 +09:00
ip_vs_proto.c ipvs: Pass ipvs not net to ip_vs_protocol_net_(init|cleanup) 2015-09-24 09:34:43 +09:00
ip_vs_rr.c ipvs: use correct address family in scheduler logs 2014-09-18 08:59:23 +09:00
ip_vs_sched.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 2015-08-04 23:57:45 -07:00
ip_vs_sed.c ipvs: use correct address family in scheduler logs 2014-09-18 08:59:23 +09:00
ip_vs_sh.c ipvs: sh: support scheduling icmp/inverse packets consistently 2015-09-01 10:33:52 +09:00
ip_vs_sync.c ipvs: Pass ipvs not net to ip_vs_sync_net_cleanup 2015-09-24 09:34:38 +09:00
ip_vs_wlc.c ipvs: use correct address family in scheduler logs 2014-09-18 08:59:23 +09:00
ip_vs_wrr.c ipvs: use correct address family in scheduler logs 2014-09-18 08:59:23 +09:00
ip_vs_xmit.c ipv4, ipv6: Pass net into ip_local_out and ip6_local_out 2015-10-08 04:27:02 -07:00
Kconfig ipvs: Add ovf scheduler 2015-08-21 09:08:39 -07:00
Makefile ipvs: Add ovf scheduler 2015-08-21 09:08:39 -07:00