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author | Jason Xing <kernelxing@tencent.com> | 2024-06-03 20:02:16 +0300 |
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committer | David S. Miller <davem@davemloft.net> | 2024-06-05 14:32:46 +0300 |
commit | a46d0ea5c94205f40ecf912d1bb7806a8a64704f (patch) | |
tree | 5ef5c41c9c4ed5ebaf58281544c65b98f2e42670 /include/net | |
parent | 712115a24b1a5318c10fc757d48d8f33815a6bfa (diff) | |
download | linux-a46d0ea5c94205f40ecf912d1bb7806a8a64704f.tar.xz |
tcp: count CLOSE-WAIT sockets for TCP_MIB_CURRESTAB
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>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
0 files changed, 0 insertions, 0 deletions