The branch main has been updated by rpokala:
URL:
https://cgit.FreeBSD.org/src/commit/?id=00a80538b4471b2978c5a1990f48189f2c692e24
commit 00a80538b4471b2978c5a1990f48189f2c692e24
Author: Greg Foster <gfos...@panasas.com>
AuthorDate: 2022-04-26 06:38:23 +0000
Commit: Ravi Pokala <rpok...@freebsd.org>
CommitDate: 2022-04-27 19:41:30 +0000
lacp: short timeout erroneously declares link-flapping
Panasas was seeing a higher-than-expected number of link-flap events.
After joint debugging with the switch vendor, we determined there were
problems on both sides; either of which might cause the occasional
event, but together caused lots of them.
On the switch side, an internal queuing issue was causing LACP PDUs --
which should be sent every second, in short-timeout mode -- to sometimes
be sent slightly later than they should have been. In some cases, two
successive PDUs were late, but we never saw three late PDUs in a row.
On the FreeBSD side, we saw a link-flap event every time there were two
late PDUs, while the spec says that it takes *three* seconds of downtime
to trigger that event. It turns out that if a PDU was received shortly
before the timer code was run, it would decrement less than a full
second after the PDU arrived. Then two delayed PDUs would cause two
additional decrements, causing it to reach zero less than three seconds
after the most-recent on-time PDU.
The solution is to note the time a PDU arrives, and only decrement if at
least a full second has elapsed since then.
Reported by: Greg Foster <gfos...@panasas.com>
Reviewed by: gallatin
Tested by: Greg Foster <gfos...@panasas.com>
MFC after: 3 days
Sponsored by: Panasas
Differential Revision: https://reviews.freebsd.org/D35070
---
sys/net/ieee8023ad_lacp.c | 18 ++++++++++++++++--
sys/net/ieee8023ad_lacp.h | 1 +
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/sys/net/ieee8023ad_lacp.c b/sys/net/ieee8023ad_lacp.c
index cf07890e051f..1e2e638fcdf5 100644
--- a/sys/net/ieee8023ad_lacp.c
+++ b/sys/net/ieee8023ad_lacp.c
@@ -49,6 +49,7 @@ __FBSDID("$FreeBSD$");
#include <sys/lock.h>
#include <sys/rwlock.h>
#include <sys/taskqueue.h>
+#include <sys/time.h>
#include <net/if.h>
#include <net/if_var.h>
@@ -1731,6 +1732,7 @@ lacp_sm_rx(struct lacp_port *lp, const struct lacpdu *du)
* EXPIRED, DEFAULTED, CURRENT -> CURRENT
*/
+ microuptime(&lp->lp_last_lacpdu_rx);
lacp_sm_rx_update_selected(lp, du);
lacp_sm_rx_update_ntt(lp, du);
lacp_sm_rx_record_pdu(lp, du);
@@ -1940,14 +1942,26 @@ static void
lacp_run_timers(struct lacp_port *lp)
{
int i;
+ struct timeval time_diff;
for (i = 0; i < LACP_NTIMER; i++) {
KASSERT(lp->lp_timer[i] >= 0,
("invalid timer value %d", lp->lp_timer[i]));
if (lp->lp_timer[i] == 0) {
continue;
- } else if (--lp->lp_timer[i] <= 0) {
- if (lacp_timer_funcs[i]) {
+ } else {
+ if (i == LACP_TIMER_CURRENT_WHILE) {
+ microuptime(&time_diff);
+ timevalsub(&time_diff, &lp->lp_last_lacpdu_rx);
+ if (time_diff.tv_sec) {
+ /* At least one sec has elapsed since
last LACP packet. */
+ --lp->lp_timer[i];
+ }
+ } else {
+ --lp->lp_timer[i];
+ }
+
+ if ((lp->lp_timer[i] <= 0) && (lacp_timer_funcs[i])) {
(*lacp_timer_funcs[i])(lp);
}
}
diff --git a/sys/net/ieee8023ad_lacp.h b/sys/net/ieee8023ad_lacp.h
index f02a9e7d9a43..0610ed855d50 100644
--- a/sys/net/ieee8023ad_lacp.h
+++ b/sys/net/ieee8023ad_lacp.h
@@ -222,6 +222,7 @@ struct lacp_port {
#define lp_key lp_actor.lip_key
#define lp_systemid lp_actor.lip_systemid
struct timeval lp_last_lacpdu;
+ struct timeval lp_last_lacpdu_rx;
int lp_lacpdu_sent;
enum lacp_mux_state lp_mux_state;
enum lacp_selected lp_selected;
