From: Jason Xing <kerneljasonxing@gmail•com>
To: edumazet@google•com, kuba@kernel•org, pabeni@redhat•com,
davem@davemloft•net, dsahern@kernel•org, matttbe@kernel•org,
martineau@kernel•org, geliang@kernel•org
Cc: netdev@vger•kernel.org, mptcp@lists•linux.dev,
kerneljasonxing@gmail•com, Jason Xing <kernelxing@tencent•com>
Subject: [PATCH net v3 1/2] tcp: count CLOSE-WAIT sockets for TCP_MIB_CURRESTAB
Date: Thu, 30 May 2024 21:13:07 +0800 [thread overview]
Message-ID: <20240530131308.59737-2-kerneljasonxing@gmail.com> (raw)
In-Reply-To: <20240530131308.59737-1-kerneljasonxing@gmail.com>
From: Jason Xing <kernelxing@tencent•com>
According to RFC 1213, we should also take CLOSE-WAIT sockets into
consideration:
"tcpCurrEstab OBJECT-TYPE
...
The number of TCP connections for which the current state
is either ESTABLISHED or CLOSE- WAIT."
After this, CurrEstab counter will display the total number of
ESTABLISHED and CLOSE-WAIT sockets.
The logic of counting
When we increment the counter?
a) if we change the state to ESTABLISHED.
b) if we change the state from SYN-RECEIVED to CLOSE-WAIT.
When we decrement the counter?
a) if the socket leaves ESTABLISHED and will never go into CLOSE-WAIT,
say, on the client side, changing from ESTABLISHED to FIN-WAIT-1.
b) if the socket leaves CLOSE-WAIT, say, on the server side, changing
from CLOSE-WAIT to LAST-ACK.
Please note: there are two chances that old state of socket can be changed
to CLOSE-WAIT in tcp_fin(). One is SYN-RECV, the other is ESTABLISHED.
So we have to take care of the former case.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Jason Xing <kernelxing@tencent•com>
---
previous discussion
Link: https://lore.kernel.org/all/20240529033104.33882-1-kerneljasonxing@gmail.com/
1. Chose to fix CurrEstab instead of introduing a new counter (Eric, Neal)
---
net/ipv4/tcp.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 5fa68e7f6ddb..902266146d0e 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2646,6 +2646,10 @@ void tcp_set_state(struct sock *sk, int state)
if (oldstate != TCP_ESTABLISHED)
TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
break;
+ case TCP_CLOSE_WAIT:
+ if (oldstate == TCP_SYN_RECV)
+ TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
+ break;
case TCP_CLOSE:
if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
@@ -2657,7 +2661,7 @@ void tcp_set_state(struct sock *sk, int state)
inet_put_port(sk);
fallthrough;
default:
- if (oldstate == TCP_ESTABLISHED)
+ if (oldstate == TCP_ESTABLISHED || oldstate == TCP_CLOSE_WAIT)
TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
}
--
2.37.3
next prev parent reply other threads:[~2024-05-30 13:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-30 13:13 [PATCH net v3 0/2] tcp/mptcp: count CLOSE-WAIT for CurrEstab Jason Xing
2024-05-30 13:13 ` Jason Xing [this message]
2024-05-31 6:23 ` [PATCH net v3 1/2] tcp: count CLOSE-WAIT sockets for TCP_MIB_CURRESTAB Eric Dumazet
2024-05-30 13:13 ` [PATCH net v3 2/2] mptcp: count CLOSE-WAIT sockets for MPTCP_MIB_CURRESTAB Jason Xing
2024-05-31 6:26 ` Eric Dumazet
2024-05-31 6:36 ` Jason Xing
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