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8547ea5f52
Lots of "TCP: tcp_fin: Impossible, sk->sk_state=7" in client side
when doing stress testing using wrk and webfsd.
There are at least two cases may trigger this warning:
1.mptcp is in syncookie, and server recv MP_JOIN SYN request,
in subflow_check_req(), the mptcp_can_accept_new_subflow()
return false, so subflow_init_req_cookie_join_save() isn't
called, i.e. not store the data present in the MP_JOIN syn
request and the random nonce in hash table - join_entries[],
but still send synack. When recv 3rd-ack,
mptcp_token_join_cookie_init_state() will return false, and
3rd-ack is dropped, then if mptcp conn is closed by client,
client will send a DATA_FIN and a MPTCP FIN, the DATA_FIN
doesn't have MP_CAPABLE or MP_JOIN,
so mptcp_subflow_init_cookie_req() will return 0, and pass
the cookie check, MP_JOIN request is fallback to normal TCP.
Server will send a TCP FIN if closed, in client side,
when process TCP FIN, it will do reset, the code path is:
tcp_data_queue()->mptcp_incoming_options()
->check_fully_established()->mptcp_subflow_reset().
mptcp_subflow_reset() will set sock state to TCP_CLOSE,
so tcp_fin will hit TCP_CLOSE, and print the warning.
2.mptcp is in syncookie, and server recv 3rd-ack, in
mptcp_subflow_init_cookie_req(), mptcp_can_accept_new_subflow()
return false, and subflow_req->mp_join is not set to 1,
so in subflow_syn_recv_sock() will not reset the MP_JOIN
subflow, but fallback to normal TCP, and then the same thing
happens when server will send a TCP FIN if closed.
For case1, subflow_check_req() return -EPERM,
then tcp_conn_request() will drop MP_JOIN SYN.
For case2, let subflow_syn_recv_sock() call
mptcp_can_accept_new_subflow(), and do fatal fallback, send reset.
Fixes:
|
||
|---|---|---|
| .. | ||
| crypto_test.c | ||
| crypto.c | ||
| ctrl.c | ||
| diag.c | ||
| Kconfig | ||
| Makefile | ||
| mib.c | ||
| mib.h | ||
| mptcp_diag.c | ||
| options.c | ||
| pm_netlink.c | ||
| pm.c | ||
| protocol.c | ||
| protocol.h | ||
| sockopt.c | ||
| subflow.c | ||
| syncookies.c | ||
| token_test.c | ||
| token.c | ||