Re: [PATCH v2] ipv4: Namespaceify tcp_tw_reuse knob

[David Miller]

From: Haishuang Yan 
Date: Sun, 25 Dec 2016 14:33:16 +0800

> Different namespaces might have different requirements to reuse
> TIME-WAIT sockets for new connections. This might be required in
> cases where different namespace applications are in place which
> require TIME_WAIT socket connections to be reduced independently
> of the host.
> 
> Signed-off-by: Haishuang Yan 
> 
> ---
> Changes in v2:
>   - Make the commit message more clearer.

Applied.

[PATCH v2] ipv4: Namespaceify tcp_tw_reuse knob

[Haishuang Yan]

Different namespaces might have different requirements to reuse
TIME-WAIT sockets for new connections. This might be required in
cases where different namespace applications are in place which
require TIME_WAIT socket connections to be reduced independently
of the host.

Signed-off-by: Haishuang Yan 

---
Changes in v2:
  - Make the commit message more clearer.
---
 include/net/netns/ipv4.h   |  1 +
 include/net/tcp.h  |  1 -
 net/ipv4/sysctl_net_ipv4.c | 14 +++---
 net/ipv4/tcp_ipv4.c|  4 ++--
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index f0cf5a1..0378e88 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -110,6 +110,7 @@ struct netns_ipv4 {
int sysctl_tcp_orphan_retries;
int sysctl_tcp_fin_timeout;
unsigned int sysctl_tcp_notsent_lowat;
+   int sysctl_tcp_tw_reuse;
 
int sysctl_igmp_max_memberships;
int sysctl_igmp_max_msf;
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 207147b..6061963 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -252,7 +252,6 @@
 extern int sysctl_tcp_rmem[3];
 extern int sysctl_tcp_app_win;
 extern int sysctl_tcp_adv_win_scale;
-extern int sysctl_tcp_tw_reuse;
 extern int sysctl_tcp_frto;
 extern int sysctl_tcp_low_latency;
 extern int sysctl_tcp_nometrics_save;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 80bc36b..22cbd61 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -433,13 +433,6 @@ static int proc_tcp_fastopen_key(struct ctl_table *ctl, 
int write,
.extra2 = _adv_win_scale_max,
},
{
-   .procname   = "tcp_tw_reuse",
-   .data   = _tcp_tw_reuse,
-   .maxlen = sizeof(int),
-   .mode   = 0644,
-   .proc_handler   = proc_dointvec
-   },
-   {
.procname   = "tcp_frto",
.data   = _tcp_frto,
.maxlen = sizeof(int),
@@ -960,6 +953,13 @@ static int proc_tcp_fastopen_key(struct ctl_table *ctl, 
int write,
.mode   = 0644,
.proc_handler   = proc_dointvec,
},
+   {
+   .procname   = "tcp_tw_reuse",
+   .data   = _net.ipv4.sysctl_tcp_tw_reuse,
+   .maxlen = sizeof(int),
+   .mode   = 0644,
+   .proc_handler   = proc_dointvec
+   },
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
{
.procname   = "fib_multipath_use_neigh",
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 30d81f5..fe9da4f 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -84,7 +84,6 @@
 #include 
 #include 
 
-int sysctl_tcp_tw_reuse __read_mostly;
 int sysctl_tcp_low_latency __read_mostly;
 
 #ifdef CONFIG_TCP_MD5SIG
@@ -120,7 +119,7 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, 
void *twp)
   and use initial timestamp retrieved from peer table.
 */
if (tcptw->tw_ts_recent_stamp &&
-   (!twp || (sysctl_tcp_tw_reuse &&
+   (!twp || (sock_net(sk)->ipv4.sysctl_tcp_tw_reuse &&
 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
if (tp->write_seq == 0)
@@ -2456,6 +2455,7 @@ static int __net_init tcp_sk_init(struct net *net)
net->ipv4.sysctl_tcp_orphan_retries = 0;
net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
+   net->ipv4.sysctl_tcp_tw_reuse = 0;
 
return 0;
 fail:
-- 
1.8.3.1