The branch main has been updated by tuexen:
URL:
https://cgit.FreeBSD.org/src/commit/?id=d31bdbc3661f6535d5ce4bc98c3687e10aa56720
commit d31bdbc3661f6535d5ce4bc98c3687e10aa56720
Author: Michael Tuexen <tue...@freebsd.org>
AuthorDate: 2025-07-21 08:07:36 +0000
Commit: Michael Tuexen <tue...@freebsd.org>
CommitDate: 2025-07-21 08:07:36 +0000
tcp: use a single counter for limiting the RST rate
Using two counters does not provide any benefit, but it provides an
externally observable signal whether there is a listening port.
Reviewed by: Nick Banks, Peter Lei
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D51440
---
sys/netinet/icmp_var.h | 9 ++++-----
sys/netinet/ip_icmp.c | 3 +--
sys/netinet/tcp_input.c | 31 ++++++++++++++++++-------------
sys/netinet/tcp_stacks/bbr.c | 22 +++++++++++-----------
sys/netinet/tcp_stacks/rack.c | 22 +++++++++++-----------
sys/netinet/tcp_stacks/rack_bbr_common.c | 2 +-
6 files changed, 46 insertions(+), 43 deletions(-)
diff --git a/sys/netinet/icmp_var.h b/sys/netinet/icmp_var.h
index b1f2b0ebf911..d6b75e482e35 100644
--- a/sys/netinet/icmp_var.h
+++ b/sys/netinet/icmp_var.h
@@ -104,11 +104,10 @@ extern int badport_bandlim(int);
#define BANDLIM_ICMP_UNREACH 0
#define BANDLIM_ICMP_ECHO 1
#define BANDLIM_ICMP_TSTAMP 2
-#define BANDLIM_RST_CLOSEDPORT 3 /* No connection, and no listeners */
-#define BANDLIM_RST_OPENPORT 4 /* No connection, listener */
-#define BANDLIM_ICMP6_UNREACH 5
-#define BANDLIM_SCTP_OOTB 6
-#define BANDLIM_MAX 7
+#define BANDLIM_TCP_RST 3
+#define BANDLIM_ICMP6_UNREACH 4
+#define BANDLIM_SCTP_OOTB 5
+#define BANDLIM_MAX 6
#endif
#endif
diff --git a/sys/netinet/ip_icmp.c b/sys/netinet/ip_icmp.c
index cb4b6df57c57..71b75d18efd0 100644
--- a/sys/netinet/ip_icmp.c
+++ b/sys/netinet/ip_icmp.c
@@ -1097,8 +1097,7 @@ static const char *icmp_rate_descrs[BANDLIM_MAX] = {
[BANDLIM_ICMP_UNREACH] = "icmp unreach",
[BANDLIM_ICMP_ECHO] = "icmp ping",
[BANDLIM_ICMP_TSTAMP] = "icmp tstamp",
- [BANDLIM_RST_CLOSEDPORT] = "closed port RST",
- [BANDLIM_RST_OPENPORT] = "open port RST",
+ [BANDLIM_TCP_RST] = "tcp reset",
[BANDLIM_ICMP6_UNREACH] = "icmp6 unreach",
[BANDLIM_SCTP_OOTB] = "sctp ootb",
};
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 1f60c0e07b13..de428ae1af6f 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -621,6 +621,7 @@ tcp_input_with_port(struct mbuf **mp, int *offp, int proto,
uint16_t port)
#endif /* INET6 */
struct tcpopt to; /* options in this segment */
char *s = NULL; /* address and port logging */
+ bool closed_port = false; /* segment is hitting a closed port */
NET_EPOCH_ASSERT();
@@ -907,7 +908,8 @@ findpcb:
log(LOG_INFO, "%s; %s: Connection attempt "
"to closed port\n", s, __func__);
}
- rstreason = BANDLIM_RST_CLOSEDPORT;
+ rstreason = BANDLIM_TCP_RST;
+ closed_port = true;
goto dropwithreset;
}
INP_LOCK_ASSERT(inp);
@@ -998,12 +1000,14 @@ findpcb:
* down or it is in the CLOSED state. Either way we drop the
* segment and send an appropriate response.
*/
- rstreason = BANDLIM_RST_CLOSEDPORT;
+ rstreason = BANDLIM_TCP_RST;
+ closed_port = true;
goto dropwithreset;
}
if ((tp->t_port != port) && (tp->t_state > TCPS_LISTEN)) {
- rstreason = BANDLIM_RST_CLOSEDPORT;
+ rstreason = BANDLIM_TCP_RST;
+ closed_port = true;
goto dropwithreset;
}
@@ -1094,7 +1098,7 @@ findpcb:
* of the failure cause.
*/
INP_WUNLOCK(inp);
- rstreason = BANDLIM_RST_OPENPORT;
+ rstreason = BANDLIM_TCP_RST;
lookupflag &= ~INPLOOKUP_WILDCARD;
goto findpcb;
}
@@ -1185,7 +1189,7 @@ tfo_socket_result:
s, __func__);
syncache_badack(&inc, port); /* XXX: Not needed! */
TCPSTAT_INC(tcps_badsyn);
- rstreason = BANDLIM_RST_OPENPORT;
+ rstreason = BANDLIM_TCP_RST;
goto dropwithreset;
}
/*
@@ -1261,7 +1265,7 @@ tfo_socket_result:
"Connection attempt to deprecated "
"IPv6 address rejected\n",
s, __func__);
- rstreason = BANDLIM_RST_OPENPORT;
+ rstreason = BANDLIM_TCP_RST;
goto dropwithreset;
}
}
@@ -1382,9 +1386,10 @@ dropwithreset:
* When blackholing do not respond with a RST but
* completely ignore the segment and drop it.
*/
- if (((rstreason == BANDLIM_RST_OPENPORT && V_blackhole == 3) ||
- (rstreason == BANDLIM_RST_CLOSEDPORT &&
- ((V_blackhole == 1 && (thflags & TH_SYN)) || V_blackhole > 1))) &&
+ if (rstreason == BANDLIM_TCP_RST &&
+ ((!closed_port && V_blackhole == 3) ||
+ (closed_port &&
+ ((V_blackhole == 1 && (thflags & TH_SYN)) || V_blackhole > 1))) &&
(V_blackhole_local || (
#ifdef INET6
isipv6 ? !in6_localip(&ip6->ip6_src) :
@@ -1967,7 +1972,7 @@ tcp_do_segment(struct tcpcb *tp, struct mbuf *m, struct
tcphdr *th,
if ((thflags & TH_ACK) &&
(SEQ_LEQ(th->th_ack, tp->snd_una) ||
SEQ_GT(th->th_ack, tp->snd_max))) {
- rstreason = BANDLIM_RST_OPENPORT;
+ rstreason = BANDLIM_TCP_RST;
tcp_log_end_status(tp,
TCP_EI_STATUS_RST_IN_FRONT);
goto dropwithreset;
}
@@ -1980,7 +1985,7 @@ tcp_do_segment(struct tcpcb *tp, struct mbuf *m, struct
tcphdr *th,
* FIN, or a RST.
*/
if ((thflags & (TH_SYN|TH_ACK)) == (TH_SYN|TH_ACK)) {
- rstreason = BANDLIM_RST_OPENPORT;
+ rstreason = BANDLIM_TCP_RST;
tcp_log_end_status(tp,
TCP_EI_STATUS_RST_IN_FRONT);
goto dropwithreset;
} else if (thflags & TH_SYN) {
@@ -2248,7 +2253,7 @@ tcp_do_segment(struct tcpcb *tp, struct mbuf *m, struct
tcphdr *th,
* for the "LAND" DoS attack.
*/
if (tp->t_state == TCPS_SYN_RECEIVED && SEQ_LT(th->th_seq, tp->irs)) {
- rstreason = BANDLIM_RST_OPENPORT;
+ rstreason = BANDLIM_TCP_RST;
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
goto dropwithreset;
}
@@ -3427,7 +3432,7 @@ dropafterack:
if (tp->t_state == TCPS_SYN_RECEIVED && (thflags & TH_ACK) &&
(SEQ_GT(tp->snd_una, th->th_ack) ||
SEQ_GT(th->th_ack, tp->snd_max)) ) {
- rstreason = BANDLIM_RST_OPENPORT;
+ rstreason = BANDLIM_TCP_RST;
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
goto dropwithreset;
}
diff --git a/sys/netinet/tcp_stacks/bbr.c b/sys/netinet/tcp_stacks/bbr.c
index e2cfec5c9275..d2636f01714e 100644
--- a/sys/netinet/tcp_stacks/bbr.c
+++ b/sys/netinet/tcp_stacks/bbr.c
@@ -8763,7 +8763,7 @@ bbr_do_syn_sent(struct mbuf *m, struct tcphdr *th, struct
socket *so,
(SEQ_LEQ(th->th_ack, tp->iss) ||
SEQ_GT(th->th_ack, tp->snd_max))) {
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
- ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset(m, tp, th, BANDLIM_TCP_RST, tlen);
return (1);
}
if ((thflags & (TH_ACK | TH_RST)) == (TH_ACK | TH_RST)) {
@@ -8965,7 +8965,7 @@ bbr_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct
socket *so,
(SEQ_LEQ(th->th_ack, tp->snd_una) ||
SEQ_GT(th->th_ack, tp->snd_max))) {
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
- ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset(m, tp, th, BANDLIM_TCP_RST, tlen);
return (1);
}
if (tp->t_flags & TF_FASTOPEN) {
@@ -8977,7 +8977,7 @@ bbr_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct
socket *so,
*/
if ((thflags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) {
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
- ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT,
tlen);
+ ctf_do_dropwithreset(m, tp, th, BANDLIM_TCP_RST, tlen);
return (1);
} else if (thflags & TH_SYN) {
/* non-initial SYN is ignored */
@@ -9010,7 +9010,7 @@ bbr_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct
socket *so,
*/
if (SEQ_LT(th->th_seq, tp->irs)) {
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
- ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset(m, tp, th, BANDLIM_TCP_RST, tlen);
return (1);
}
if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen,
&ret_val)) {
@@ -9288,7 +9288,7 @@ bbr_do_established(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (sbavail(&so->so_snd)) {
if (ctf_progress_timeout_check(tp, true)) {
bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -9385,7 +9385,7 @@ bbr_do_close_wait(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (sbavail(&so->so_snd)) {
if (ctf_progress_timeout_check(tp, true)) {
bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -9535,7 +9535,7 @@ bbr_do_fin_wait_1(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (sbavail(&so->so_snd)) {
if (ctf_progress_timeout_check(tp, true)) {
bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -9637,7 +9637,7 @@ bbr_do_closing(struct mbuf *m, struct tcphdr *th, struct
socket *so,
if (sbavail(&so->so_snd)) {
if (ctf_progress_timeout_check(tp, true)) {
bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -9739,7 +9739,7 @@ bbr_do_lastack(struct mbuf *m, struct tcphdr *th, struct
socket *so,
if (sbavail(&so->so_snd)) {
if (ctf_progress_timeout_check(tp, true)) {
bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -9848,7 +9848,7 @@ bbr_do_fin_wait_2(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (sbavail(&so->so_snd)) {
if (ctf_progress_timeout_check(tp, true)) {
bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -11510,7 +11510,7 @@ bbr_do_segment_nounlock(struct tcpcb *tp, struct mbuf
*m, struct tcphdr *th,
if ((tp->t_state == TCPS_SYN_SENT) && (thflags & TH_ACK) &&
(SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) {
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
- ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT,
tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST, tlen);
return (1);
}
if (tiwin > bbr->r_ctl.rc_high_rwnd)
diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c
index 7ccfff66b20d..5280f18dc983 100644
--- a/sys/netinet/tcp_stacks/rack.c
+++ b/sys/netinet/tcp_stacks/rack.c
@@ -12876,7 +12876,7 @@ rack_do_syn_sent(struct mbuf *m, struct tcphdr *th,
struct socket *so,
(SEQ_LEQ(th->th_ack, tp->iss) ||
SEQ_GT(th->th_ack, tp->snd_max))) {
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
- ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset(m, tp, th, BANDLIM_TCP_RST, tlen);
return (1);
}
if ((thflags & (TH_ACK | TH_RST)) == (TH_ACK | TH_RST)) {
@@ -13090,7 +13090,7 @@ rack_do_syn_recv(struct mbuf *m, struct tcphdr *th,
struct socket *so,
(SEQ_LEQ(th->th_ack, tp->snd_una) ||
SEQ_GT(th->th_ack, tp->snd_max))) {
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
- ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset(m, tp, th, BANDLIM_TCP_RST, tlen);
return (1);
}
if (tp->t_flags & TF_FASTOPEN) {
@@ -13103,7 +13103,7 @@ rack_do_syn_recv(struct mbuf *m, struct tcphdr *th,
struct socket *so,
*/
if ((thflags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) {
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
- ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT,
tlen);
+ ctf_do_dropwithreset(m, tp, th, BANDLIM_TCP_RST, tlen);
return (1);
} else if (thflags & TH_SYN) {
/* non-initial SYN is ignored */
@@ -13137,7 +13137,7 @@ rack_do_syn_recv(struct mbuf *m, struct tcphdr *th,
struct socket *so,
*/
if (SEQ_LT(th->th_seq, tp->irs)) {
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
- ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset(m, tp, th, BANDLIM_TCP_RST, tlen);
return (1);
}
if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen,
&ret_val)) {
@@ -13400,7 +13400,7 @@ rack_do_established(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (sbavail(&so->so_snd)) {
if (ctf_progress_timeout_check(tp, true)) {
rack_log_progress_event(rack, tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -13496,7 +13496,7 @@ rack_do_close_wait(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (ctf_progress_timeout_check(tp, true)) {
rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -13646,7 +13646,7 @@ rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (ctf_progress_timeout_check(tp, true)) {
rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -13747,7 +13747,7 @@ rack_do_closing(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (ctf_progress_timeout_check(tp, true)) {
rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -13849,7 +13849,7 @@ rack_do_lastack(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (ctf_progress_timeout_check(tp, true)) {
rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -13953,7 +13953,7 @@ rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (ctf_progress_timeout_check(tp, true)) {
rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
tp, tick, PROGRESS_DROP,
__LINE__);
- ctf_do_dropwithreset_conn(m, tp, th,
BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_TCP_RST,
tlen);
return (1);
}
}
@@ -16656,7 +16656,7 @@ rack_do_segment_nounlock(struct tcpcb *tp, struct mbuf
*m, struct tcphdr *th,
if ((tp->t_state == TCPS_SYN_SENT) && (thflags & TH_ACK) &&
(SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) {
tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
- ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset(m, tp, th, BANDLIM_TCP_RST, tlen);
#ifdef TCP_ACCOUNTING
sched_unpin();
#endif
diff --git a/sys/netinet/tcp_stacks/rack_bbr_common.c
b/sys/netinet/tcp_stacks/rack_bbr_common.c
index da26b8cb1f9b..d1c4ba58bf55 100644
--- a/sys/netinet/tcp_stacks/rack_bbr_common.c
+++ b/sys/netinet/tcp_stacks/rack_bbr_common.c
@@ -672,7 +672,7 @@ ctf_do_dropafterack(struct mbuf *m, struct tcpcb *tp,
struct tcphdr *th, int32_t
(SEQ_GT(tp->snd_una, th->th_ack) ||
SEQ_GT(th->th_ack, tp->snd_max))) {
*ret_val = 1;
- ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
+ ctf_do_dropwithreset(m, tp, th, BANDLIM_TCP_RST, tlen);
return;
} else
*ret_val = 0;
