ipv6 addrconf: implement RFC7559 router solicitation backoff
This implements:
https://tools.ietf.org/html/rfc7559
Backoff is performed according to RFC3315 section 14:
https://tools.ietf.org/html/rfc3315#section-14
We allow setting /proc/sys/net/ipv6/conf/*/router_solicitations
to a negative value meaning an unlimited number of retransmits,
and we make this the new default (inline with the RFC).
We also add a new setting:
/proc/sys/net/ipv6/conf/*/router_solicitation_max_interval
defaulting to 1 hour (per RFC recommendation).
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Acked-by: Erik Kline <ek@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 9826d3a..f2d0727 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -1,8 +1,9 @@
#ifndef _ADDRCONF_H
#define _ADDRCONF_H
-#define MAX_RTR_SOLICITATIONS 3
+#define MAX_RTR_SOLICITATIONS -1 /* unlimited */
#define RTR_SOLICITATION_INTERVAL (4*HZ)
+#define RTR_SOLICITATION_MAX_INTERVAL (3600*HZ) /* 1 hour */
#define MIN_VALID_LIFETIME (2*3600) /* 2 hours */
