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tcp: in tcp_usr_detach() remove special handling of compressed time-wait

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Differential revision:	https://reviews.freebsd.org/D36399
This commit is contained in:
Gleb Smirnoff 2022-10-06 19:22:23 -07:00
parent 0d7445193a
commit 9c3507f919
1 changed files with 7 additions and 52 deletions
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59
sys/netinet/tcp_usrreq.c
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@ -216,58 +216,13 @@ tcp_usr_detach(struct socket *so)
tp = intotcpcb(inp);
if (inp->inp_flags & INP_TIMEWAIT) {
/*
* There are two cases to handle: one in which the time wait
* state is being discarded (INP_DROPPED), and one in which
* this connection will remain in timewait. In the former,
* it is time to discard all state (except tcptw, which has
* already been discarded by the timewait close code, which
* should be further up the call stack somewhere). In the
* latter case, we detach from the socket, but leave the pcb
* present until timewait ends.
*
* XXXRW: Would it be cleaner to free the tcptw here?
*
* Astute question indeed, from twtcp perspective there are
* four cases to consider:
*
* #1 tcp_usr_detach is called at tcptw creation time by
* tcp_twstart, then do not discard the newly created tcptw
* and leave inpcb present until timewait ends
* #2 tcp_usr_detach is called at tcptw creation time by
* tcp_twstart, but connection is local and tw will be
* discarded immediately
* #3 tcp_usr_detach is called at timewait end (or reuse) by
* tcp_twclose, then the tcptw has already been discarded
* (or reused) and inpcb is freed here
* #4 tcp_usr_detach is called() after timewait ends (or reuse)
* (e.g. by soclose), then tcptw has already been discarded
* (or reused) and inpcb is freed here
*
* In all three cases the tcptw should not be freed here.
*/
if (inp->inp_flags & INP_DROPPED) {
KASSERT(tp == NULL, ("tcp_detach: INP_TIMEWAIT && "
"INP_DROPPED && tp != NULL"));
in_pcbdetach(inp);
in_pcbfree(inp);
} else {
in_pcbdetach(inp);
INP_WUNLOCK(inp);
}
} else {
/*
* If the connection is not in timewait, it must be either
* dropped or embryonic.
*/
KASSERT(inp->inp_flags & INP_DROPPED ||
tp->t_state < TCPS_SYN_SENT,
("%s: inp %p not dropped or embryonic", __func__, inp));
tcp_discardcb(tp);
in_pcbdetach(inp);
in_pcbfree(inp);
}
KASSERT(inp->inp_flags & INP_DROPPED ||
tp->t_state < TCPS_SYN_SENT,
("%s: inp %p not dropped or embryonic", __func__, inp));
tcp_discardcb(tp);
in_pcbdetach(inp);
in_pcbfree(inp);
}
#ifdef INET