From 2690048c01f32bf45d1c1e1ab3079bc10ad2aea7 Mon Sep 17 00:00:00 2001 From: William Manley Date: Tue, 6 Aug 2013 19:03:15 +0100 Subject: [PATCH] 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 ++ net/ipv4/devinet.c | 8 ++++++++ net/ipv4/igmp.c | 19 +++++++++++++++++-- 3 files changed, 27 insertions(+), 2 deletions(-) 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, diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index 87d47ce9fa33..a1b5bcbd04ae 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -73,6 +73,8 @@ static struct ipv4_devconf ipv4_devconf = { [IPV4_DEVCONF_SEND_REDIRECTS - 1] = 1, [IPV4_DEVCONF_SECURE_REDIRECTS - 1] = 1, [IPV4_DEVCONF_SHARED_MEDIA - 1] = 1, + [IPV4_DEVCONF_IGMPV2_UNSOLICITED_REPORT_INTERVAL - 1] = 10000 /*ms*/, + [IPV4_DEVCONF_IGMPV3_UNSOLICITED_REPORT_INTERVAL - 1] = 1000 /*ms*/, }, }; @@ -83,6 +85,8 @@ static struct ipv4_devconf ipv4_devconf_dflt = { [IPV4_DEVCONF_SECURE_REDIRECTS - 1] = 1, [IPV4_DEVCONF_SHARED_MEDIA - 1] = 1, [IPV4_DEVCONF_ACCEPT_SOURCE_ROUTE - 1] = 1, + [IPV4_DEVCONF_IGMPV2_UNSOLICITED_REPORT_INTERVAL - 1] = 10000 /*ms*/, + [IPV4_DEVCONF_IGMPV3_UNSOLICITED_REPORT_INTERVAL - 1] = 1000 /*ms*/, }, }; @@ -2096,6 +2100,10 @@ static struct devinet_sysctl_table { DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP_PVLAN, "proxy_arp_pvlan"), DEVINET_SYSCTL_RW_ENTRY(FORCE_IGMP_VERSION, "force_igmp_version"), + DEVINET_SYSCTL_RW_ENTRY(IGMPV2_UNSOLICITED_REPORT_INTERVAL, + "igmpv2_unsolicited_report_interval"), + DEVINET_SYSCTL_RW_ENTRY(IGMPV3_UNSOLICITED_REPORT_INTERVAL, + "igmpv3_unsolicited_report_interval"), DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"), DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"), diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index ceb19ab9cf9d..d6c0e64ec97f 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -142,10 +142,25 @@ static int unsolicited_report_interval(struct in_device *in_dev) { + int interval_ms, interval_jiffies; + if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev)) - return IGMP_V2_Unsolicited_Report_Interval; + interval_ms = IN_DEV_CONF_GET( + in_dev, + IGMPV2_UNSOLICITED_REPORT_INTERVAL); else /* v3 */ - return IGMP_V3_Unsolicited_Report_Interval; + interval_ms = IN_DEV_CONF_GET( + in_dev, + IGMPV3_UNSOLICITED_REPORT_INTERVAL); + + interval_jiffies = msecs_to_jiffies(interval_ms); + + /* _timer functions can't handle a delay of 0 jiffies so ensure + * we always return a positive value. + */ + if (interval_jiffies <= 0) + interval_jiffies = 1; + return interval_jiffies; } static void igmpv3_add_delrec(struct in_device *in_dev, struct ip_mc_list *im);