diff options
| author | Marius Halden <marius.halden@modirum.com> | 2021-10-31 20:18:42 +0000 |
|---|---|---|
| committer | Kristof Provost <kp@FreeBSD.org> | 2021-11-22 01:55:13 +0000 |
| commit | 1c16de99bd7ddddad9d5877ba0f91aa2a2f57eb3 (patch) | |
| tree | eb891707a060584789b187dadb6a8587295af515 | |
| parent | 2107407b25eeeab89556c36ad789a4b23ec9a5f7 (diff) | |
carp: deal with negative net.inet.carp.demotion
Given nodes 1 and 2, where node 1 has an advskew of 0 and node 2 has an
advskew of 100, making them master and backup respectively.
If net.inet.carp.demotion is set to a negative value on node 1, node 2
might become master while node 1 still retains it master status. Wether
or not node 2 becomes master seems to depend on the nodes advskew and
what the demotion sysctl was set to on node 1.
The reason for node 2 becoming master seems to be that the calculated
advskew taking demotion into account is truncated to a single unsigned
byte when copied into the carp header for sending, and node 1 stays
master since it takes uses the whole non-truncated calculated advskew
when deciding wether to stay master.
PR: 259528
Reviewed by: donner, glebius
MFC after: 3 weeks
Sponsored by: Modirum MDPay
Differential Revision: https://reviews.freebsd.org/D32759
(cherry picked from commit 1019354b54161c140d10a8203ff1e849c09c8010)
| -rw-r--r-- | sys/netinet/ip_carp.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/sys/netinet/ip_carp.c b/sys/netinet/ip_carp.c index f4f051d14fee..acf819df694a 100644 --- a/sys/netinet/ip_carp.c +++ b/sys/netinet/ip_carp.c @@ -301,7 +301,9 @@ SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID_AUTO, stats, struct carpstats, #define DEMOTE_ADVSKEW(sc) \ (((sc)->sc_advskew + V_carp_demotion > CARP_MAXSKEW) ? \ - CARP_MAXSKEW : ((sc)->sc_advskew + V_carp_demotion)) + CARP_MAXSKEW : \ + (((sc)->sc_advskew + V_carp_demotion < 0) ? \ + 0 : ((sc)->sc_advskew + V_carp_demotion))) static void carp_input_c(struct mbuf *, struct carp_header *, sa_family_t); static struct carp_softc |