[PATCH 4.14 014/106] netfilter: ipvs: Fix reuse connection if RS weight is 0

Greg Kroah-Hartman
2021-12-06T15:10:43Z

From: yangxingwu <xingwu.yang@gmail.com>

[ Upstream commit c95c07836fa4c1767ed11d8eca0769c652760e32 ]

We are changing expire_nodest_conn to work even for reused connections when
conn_reuse_mode=0, just as what was done with commit dc7b3eb900aa ("ipvs:
Fix reuse connection if real server is dead").

For controlled and persistent connections, the new connection will get the
needed real server depending on the rules in ip_vs_check_template().

Fixes: d752c3645717 ("ipvs: allow rescheduling of new connections when port reuse is detected")
Co-developed-by: Chuanqi Liu <legend050709@qq.com>
Signed-off-by: Chuanqi Liu <legend050709@qq.com>
Signed-off-by: yangxingwu <xingwu.yang@gmail.com>
Acked-by: Simon Horman <horms@verge.net.au>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Documentation/networking/ipvs-sysctl.txt | 3 +--
net/netfilter/ipvs/ip_vs_core.c | 8 ++++----
2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/Documentation/networking/ipvs-sysctl.txt b/Documentation/networking/ipvs-sysctl.txt
index 056898685d408..fc531c29a2e83 100644
--- a/Documentation/networking/ipvs-sysctl.txt
+++ b/Documentation/networking/ipvs-sysctl.txt
@@ -30,8 +30,7 @@ conn_reuse_mode - INTEGER

0: disable any special handling on port reuse. The new
connection will be delivered to the same real server that was
- servicing the previous connection. This will effectively
- disable expire_nodest_conn.
+ servicing the previous connection.

bit 1: enable rescheduling of new connections when it is safe.
That is, whenever expire_nodest_conn and for TCP sockets, when
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index a95fe5fe9f046..4b9cd1c1c9987 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -1838,7 +1838,6 @@ ip_vs_in(struct netns_ipvs *ipvs, unsigned int hooknum, struct sk_buff *skb, int
struct ip_vs_proto_data *pd;
struct ip_vs_conn *cp;
int ret, pkts;
- int conn_reuse_mode;
struct sock *sk;

/* Already marked as IPVS request or reply? */
@@ -1914,15 +1913,16 @@ ip_vs_in(struct netns_ipvs *ipvs, unsigned int hooknum, struct sk_buff *skb, int
*/
cp = pp->conn_in_get(ipvs, af, skb, &iph);

- conn_reuse_mode = sysctl_conn_reuse_mode(ipvs);
- if (conn_reuse_mode && !iph.fragoffs && is_new_conn(skb, &iph) && cp) {
+ if (!iph.fragoffs && is_new_conn(skb, &iph) && cp) {
+ int conn_reuse_mode = sysctl_conn_reuse_mode(ipvs);
bool old_ct = false, resched = false;

if (unlikely(sysctl_expire_nodest_conn(ipvs)) && cp->dest &&
unlikely(!atomic_read(&cp->dest->weight))) {
resched = true;
old_ct = ip_vs_conn_uses_old_conntrack(cp, skb);
- } else if (is_new_conn_expected(cp, conn_reuse_mode)) {
+ } else if (conn_reuse_mode &&
+ is_new_conn_expected(cp, conn_reuse_mode)) {
old_ct = ip_vs_conn_uses_old_conntrack(cp, skb);
if (!atomic_read(&cp->n_control)) {
resched = true;
--
2.33.0