ipv6: add sysctl_mld_qrv to configure query robustness variable
This patch adds a new sysctl_mld_qrv knob to configure the mldv1/v2 query
robustness variable. It specifies how many retransmit of unsolicited mld
retransmit should happen. Admins might want to tune this on lossy links.
Also reset mld state on interface down/up, so we pick up new sysctl
settings during interface up event.
IPv6 certification requests this knob to be available.
I didn't make this knob netns specific, as it is mostly a setting in a
physical environment and should be per host.
Cc: Flavio Leitner <fbl@redhat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Flavio Leitner <fbl@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 7088179..6491942 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -121,6 +121,7 @@
#define IPV6_MLD_MAX_MSF 64
int sysctl_mld_max_msf __read_mostly = IPV6_MLD_MAX_MSF;
+int sysctl_mld_qrv __read_mostly = MLD_QRV_DEFAULT;
/*
* socket join on multicast group
@@ -1191,15 +1192,16 @@
* and SHOULD NOT be one. Catch this here if we ever run
* into such a case in future.
*/
+ const int min_qrv = min(MLD_QRV_DEFAULT, sysctl_mld_qrv);
WARN_ON(idev->mc_qrv == 0);
if (mlh2->mld2q_qrv > 0)
idev->mc_qrv = mlh2->mld2q_qrv;
- if (unlikely(idev->mc_qrv < 2)) {
+ if (unlikely(idev->mc_qrv < min_qrv)) {
net_warn_ratelimited("IPv6: MLD: clamping QRV from %u to %u!\n",
- idev->mc_qrv, MLD_QRV_DEFAULT);
- idev->mc_qrv = MLD_QRV_DEFAULT;
+ idev->mc_qrv, min_qrv);
+ idev->mc_qrv = min_qrv;
}
}
@@ -2478,6 +2480,14 @@
mld_clear_delrec(idev);
}
+static void ipv6_mc_reset(struct inet6_dev *idev)
+{
+ idev->mc_qrv = sysctl_mld_qrv;
+ idev->mc_qi = MLD_QI_DEFAULT;
+ idev->mc_qri = MLD_QRI_DEFAULT;
+ idev->mc_v1_seen = 0;
+ idev->mc_maxdelay = unsolicited_report_interval(idev);
+}
/* Device going up */
@@ -2488,6 +2498,7 @@
/* Install multicast list, except for all-nodes (already installed) */
read_lock_bh(&idev->lock);
+ ipv6_mc_reset(idev);
for (i = idev->mc_list; i; i = i->next)
igmp6_group_added(i);
read_unlock_bh(&idev->lock);
@@ -2508,13 +2519,7 @@
(unsigned long)idev);
setup_timer(&idev->mc_dad_timer, mld_dad_timer_expire,
(unsigned long)idev);
-
- idev->mc_qrv = MLD_QRV_DEFAULT;
- idev->mc_qi = MLD_QI_DEFAULT;
- idev->mc_qri = MLD_QRI_DEFAULT;
-
- idev->mc_maxdelay = unsolicited_report_interval(idev);
- idev->mc_v1_seen = 0;
+ ipv6_mc_reset(idev);
write_unlock_bh(&idev->lock);
}
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 0c56c93..c5c10fa 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -16,6 +16,8 @@
#include <net/addrconf.h>
#include <net/inet_frag.h>
+static int one = 1;
+
static struct ctl_table ipv6_table_template[] = {
{
.procname = "bindv6only",
@@ -63,6 +65,14 @@
.mode = 0644,
.proc_handler = proc_dointvec
},
+ {
+ .procname = "mld_qrv",
+ .data = &sysctl_mld_qrv,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &one
+ },
{ }
};