From 8013d1d7eafb0589ca766db6b74026f76b7f5cb4 Mon Sep 17 00:00:00 2001 From: Hangbin Liu Date: Thu, 30 Jul 2015 14:28:42 +0800 Subject: net/ipv6: add sysctl option accept_ra_min_hop_limit Commit 6fd99094de2b ("ipv6: Don't reduce hop limit for an interface") disabled accept hop limit from RA if it is smaller than the current hop limit for security stuff. But this behavior kind of break the RFC definition. RFC 4861, 6.3.4. Processing Received Router Advertisements A Router Advertisement field (e.g., Cur Hop Limit, Reachable Time, and Retrans Timer) may contain a value denoting that it is unspecified. In such cases, the parameter should be ignored and the host should continue using whatever value it is already using. If the received Cur Hop Limit value is non-zero, the host SHOULD set its CurHopLimit variable to the received value. So add sysctl option accept_ra_min_hop_limit to let user choose the minimum hop limit value they can accept from RA. And set default to 1 to meet RFC standards. Signed-off-by: Hangbin Liu Acked-by: YOSHIFUJI Hideaki Signed-off-by: David S. Miller --- include/linux/ipv6.h | 1 + include/uapi/linux/ipv6.h | 1 + 2 files changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 06ed637225b8..cb9dcad72372 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -29,6 +29,7 @@ struct ipv6_devconf { __s32 max_desync_factor; __s32 max_addresses; __s32 accept_ra_defrtr; + __s32 accept_ra_min_hop_limit; __s32 accept_ra_pinfo; #ifdef CONFIG_IPV6_ROUTER_PREF __s32 accept_ra_rtr_pref; diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index 641a146ead7d..80f3b74446a1 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -172,6 +172,7 @@ enum { DEVCONF_ACCEPT_RA_MTU, DEVCONF_STABLE_SECRET, DEVCONF_USE_OIF_ADDRS_ONLY, + DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT, DEVCONF_MAX }; -- cgit v1.2.3