Re: [PATCH nf-next v6] netfilter: ipvs: Fix reuse connection if RS weight is 0

From: Julian Anastasov
Date: Thu Nov 04 2021 - 12:57:28 EST



Hello,

On Thu, 4 Nov 2021, yangxingwu wrote:

> 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@xxxxxx>
> Signed-off-by: Chuanqi Liu <legend050709@xxxxxx>
> Signed-off-by: yangxingwu <xingwu.yang@xxxxxxxxx>

Acked-by: Julian Anastasov <ja@xxxxxx>

> ---
> Documentation/networking/ipvs-sysctl.rst | 3 +--
> net/netfilter/ipvs/ip_vs_core.c | 8 ++++----
> 2 files changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/networking/ipvs-sysctl.rst b/Documentation/networking/ipvs-sysctl.rst
> index 2afccc63856e..1cfbf1add2fc 100644
> --- a/Documentation/networking/ipvs-sysctl.rst
> +++ b/Documentation/networking/ipvs-sysctl.rst
> @@ -37,8 +37,7 @@ 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 128690c512df..393058a43aa7 100644
> --- a/net/netfilter/ipvs/ip_vs_core.c
> +++ b/net/netfilter/ipvs/ip_vs_core.c
> @@ -1964,7 +1964,6 @@ 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? */
> @@ -2041,15 +2040,16 @@ ip_vs_in(struct netns_ipvs *ipvs, unsigned int hooknum, struct sk_buff *skb, int
> cp = INDIRECT_CALL_1(pp->conn_in_get, ip_vs_conn_in_get_proto,
> 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;
> --
> 2.30.2

Regards

--
Julian Anastasov <ja@xxxxxx>