commit bd11f0741fa5a2c296629898ad07759dd12b35bb
author Maciej Żenczykowski <maze@google.com> Tue Sep 27 23:57:58 2016 -0700
committer David S. Miller <davem@davemloft.net> Fri Sep 30 01:54:28 2016 -0400
tree e25b67382a3798f6274bc4e85c06a1133deb56a2
parent bcdc6efabda3ba6a67f4cb8915873e7d6759b7e6

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>

include/linux/ipv6.h

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index c6dbcd8..7e9a789 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -18,6 +18,7 @@
 	__s32		dad_transmits;
 	__s32		rtr_solicits;
 	__s32		rtr_solicit_interval;
+	__s32		rtr_solicit_max_interval;
 	__s32		rtr_solicit_delay;
 	__s32		force_mld_version;
 	__s32		mldv1_unsolicited_report_interval;

include/net/addrconf.h

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 */
 

include/net/if_inet6.h

diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index 1c8b682..515352c 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -201,6 +201,7 @@
 	struct ipv6_devstat	stats;
 
 	struct timer_list	rs_timer;
+	__s32			rs_interval;	/* in jiffies */
 	__u8			rs_probes;
 
 	__u8			addr_gen_mode;

include/uapi/linux/ipv6.h

diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
index 3958760..8c27723 100644
--- a/include/uapi/linux/ipv6.h
+++ b/include/uapi/linux/ipv6.h
@@ -177,6 +177,7 @@
 	DEVCONF_DROP_UNICAST_IN_L2_MULTICAST,
 	DEVCONF_DROP_UNSOLICITED_NA,
 	DEVCONF_KEEP_ADDR_ON_DOWN,
+	DEVCONF_RTR_SOLICIT_MAX_INTERVAL,
 	DEVCONF_MAX
 };