From 7c6bb7d2faaf1ed7d78bafd712476e4cf2cf0d7d Mon Sep 17 00:00:00 2001 From: David Ahern Date: Thu, 11 Oct 2018 20:17:21 -0700 Subject: net/ipv6: Add knob to skip DELROUTE message on device down Another difference between IPv4 and IPv6 is the generation of RTM_DELROUTE notifications when a device is taken down (admin down) or deleted. IPv4 does not generate a message for routes evicted by the down or delete; IPv6 does. A NOS at scale really needs to avoid these messages and have IPv4 and IPv6 behave similarly, relying on userspace to handle link notifications and evict the routes. At this point existing user behavior needs to be preserved. Since notifications are a global action (not per app) the only way to preserve existing behavior and allow the messages to be skipped is to add a new sysctl (net/ipv6/route/skip_notify_on_dev_down) which can be set to disable the notificatioons. IPv6 route code already supports the option to skip the message (it is used for multipath routes for example). Besides the new sysctl we need to pass the skip_notify setting through the generic fib6_clean and fib6_walk functions to fib6_clean_node and to set skip_notify on calls to __ip_del_rt for the addrconf_ifdown path. Signed-off-by: David Ahern Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation/networking/ip-sysctl.txt') diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 960de8fe3f40..163b5ff1073c 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1442,6 +1442,14 @@ max_hbh_length - INTEGER header. Default: INT_MAX (unlimited) +skip_notify_on_dev_down - BOOLEAN + Controls whether an RTM_DELROUTE message is generated for routes + removed when a device is taken down or deleted. IPv4 does not + generate this message; IPv6 does by default. Setting this sysctl + to true skips the message, making IPv4 and IPv6 on par in relying + on userspace caches to track link events and evict routes. + Default: false (generate message) + IPv6 Fragmentation: ip6frag_high_thresh - INTEGER -- cgit v1.2.3-59-g8ed1b