From 2690048c01f32bf45d1c1e1ab3079bc10ad2aea7 Mon Sep 17 00:00:00 2001 From: William Manley Date: Tue, 6 Aug 2013 19:03:15 +0100 Subject: net: igmp: Allow user-space configuration of igmp unsolicited report interval Adds the new procfs knobs: /proc/sys/net/ipv4/conf/*/igmpv2_unsolicited_report_interval /proc/sys/net/ipv4/conf/*/igmpv3_unsolicited_report_interval Which will allow userspace configuration of the IGMP unsolicited report interval (see below) in milliseconds. The defaults are 10000ms for IGMPv2 and 1000ms for IGMPv3 in accordance with RFC2236 and RFC3376. Background: If an IGMP join packet is lost you will not receive data sent to the multicast group so if no data arrives from that multicast group in a period of time after the IGMP join a second IGMP join will be sent. The delay between joins is the "IGMP Unsolicited Report Interval". Prior to this patch this value was hard coded in the kernel to 10s for IGMPv2 and 1s for IGMPv3. 10s is unsuitable for some use-cases, such as IPTV as it can cause channel change to be slow in the presence of packet loss. This patch allows the value to be overridden from userspace for both IGMPv2 and IGMPv3 such that it can be tuned accoding to the network. Tested with Wireshark and a simple program to join a (non-existent) multicast group. The distribution of timings for the second join differ based upon setting the procfs knobs. igmpvX_unsolicited_report_interval is intended to follow the pattern established by force_igmp_version, and while a procfs entry has been added a corresponding sysctl knob has not as it is my understanding that sysctl is deprecated[1]. [1]: http://lwn.net/Articles/247243/ Signed-off-by: William Manley Acked-by: Hannes Frederic Sowa Acked-by: Benjamin LaHaise Signed-off-by: David S. Miller --- include/linux/inetdevice.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h index 0a4a6cb35338..c796ce26c7c0 100644 --- a/include/linux/inetdevice.h +++ b/include/linux/inetdevice.h @@ -28,6 +28,8 @@ enum IPV4_DEVCONF_ARPFILTER, IPV4_DEVCONF_MEDIUM_ID, IPV4_DEVCONF_FORCE_IGMP_VERSION, + IPV4_DEVCONF_IGMPV2_UNSOLICITED_REPORT_INTERVAL, + IPV4_DEVCONF_IGMPV3_UNSOLICITED_REPORT_INTERVAL, IPV4_DEVCONF_NOXFRM, IPV4_DEVCONF_NOPOLICY, IPV4_DEVCONF_ARP_ANNOUNCE, -- cgit v1.2.3-59-g8ed1b