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tcp: honor drop_synfin sysctl variable in TIME-WAIT

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Reviewed by:		rrs@
MFC after:		1 week
Sponsored by:		Netflix, Inc.
Differential Revision:	https://reviews.freebsd.org/D36862
This commit is contained in:
Michael Tuexen 2022-10-03 12:48:30 +02:00
parent ffbc2a58b1
commit f8b5681094
1 changed files with 12 additions and 2 deletions
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14
sys/netinet/tcp_timewait.c
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@ -50,9 +50,7 @@ __FBSDID("$FreeBSD$");
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#ifndef INVARIANTS
#include <sys/syslog.h>
#endif
#include <sys/protosw.h>
#include <sys/random.h>
@ -389,6 +387,7 @@ tcp_twcheck(struct inpcb *inp, struct tcpopt *to, struct tcphdr *th,
struct mbuf *m, int tlen)
{
struct tcptw *tw;
char *s;
int thflags;
tcp_seq seq;
@ -447,6 +446,17 @@ tcp_twcheck(struct inpcb *inp, struct tcpopt *to, struct tcphdr *th,
*/
#endif
/* Honor the drop_synfin sysctl variable. */
if ((thflags & TH_SYN) && (thflags & TH_FIN) && V_drop_synfin) {
if ((s = tcp_log_addrs(&inp->inp_inc, th, NULL, NULL))) {
log(LOG_DEBUG, "%s; %s: "
"SYN|FIN segment ignored (based on "
"sysctl setting)\n", s, __func__);
free(s, M_TCPLOG);
}
goto drop;
}
/*
* If a new connection request is received
* while in TIME_WAIT, drop the old connection