From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin LaHaise Subject: Re: [PATCH v4 1/3] net: igmp: Reduce Unsolicited report interval to 1s when using IGMPv3 Date: Wed, 7 Aug 2013 09:43:20 -0400 Message-ID: <20130807134320.GL8043@kvack.org> References: <20130731063442.GA10498@order.stressinduktion.org> <1375812195-6575-1-git-send-email-william.manley@youview.com> <1375812195-6575-2-git-send-email-william.manley@youview.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, luky-37@hotmail.com, sergei.shtylyov@cogentembedded.com, bhutchings@solarflare.com, davem@davemloft.net, hannes@stressinduktion.org To: William Manley Return-path: Received: from kanga.kvack.org ([205.233.56.17]:36116 "EHLO kanga.kvack.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933144Ab3HGNnV (ORCPT ); Wed, 7 Aug 2013 09:43:21 -0400 Content-Disposition: inline In-Reply-To: <1375812195-6575-2-git-send-email-william.manley@youview.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Aug 06, 2013 at 07:03:13PM +0100, William Manley wrote: > 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". > > Previously this value was hard coded to be chosen randomly between 0-10s. > This can be too long for some use-cases, such as IPTV as it can cause > channel change to be slow in the presence of packet loss. > > The value 10s has come from IGMPv2 RFC2236, which was reduced to 1s in > IGMPv3 RFC3376. This patch makes the kernel use the 1s value from the > later RFC if we are operating in IGMPv3 mode. IGMPv2 behaviour is > unaffected. > > 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 /proc/sys/net/ipv4/conf/eth0/force_igmp_version. > > Signed-off-by: William Manley Acked-by: Benjamin LaHaise -ben > --- > net/ipv4/igmp.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c > index d8c2327..9f0aaea 100644 > --- a/net/ipv4/igmp.c > +++ b/net/ipv4/igmp.c > @@ -113,7 +113,8 @@ > > #define IGMP_V1_Router_Present_Timeout (400*HZ) > #define IGMP_V2_Router_Present_Timeout (400*HZ) > -#define IGMP_Unsolicited_Report_Interval (10*HZ) > +#define IGMP_V2_Unsolicited_Report_Interval (10*HZ) > +#define IGMP_V3_Unsolicited_Report_Interval (1*HZ) > #define IGMP_Query_Response_Interval (10*HZ) > #define IGMP_Unsolicited_Report_Count 2 > > @@ -138,6 +139,14 @@ > ((in_dev)->mr_v2_seen && \ > time_before(jiffies, (in_dev)->mr_v2_seen))) > > +static int unsolicited_report_interval(struct in_device *in_dev) > +{ > + if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev)) > + return IGMP_V2_Unsolicited_Report_Interval; > + else /* v3 */ > + return IGMP_V3_Unsolicited_Report_Interval; > +} > + > static void igmpv3_add_delrec(struct in_device *in_dev, struct ip_mc_list *im); > static void igmpv3_del_delrec(struct in_device *in_dev, __be32 multiaddr); > static void igmpv3_clear_delrec(struct in_device *in_dev); > @@ -719,7 +728,8 @@ static void igmp_ifc_timer_expire(unsigned long data) > igmpv3_send_cr(in_dev); > if (in_dev->mr_ifc_count) { > in_dev->mr_ifc_count--; > - igmp_ifc_start_timer(in_dev, IGMP_Unsolicited_Report_Interval); > + igmp_ifc_start_timer(in_dev, > + unsolicited_report_interval(in_dev)); > } > __in_dev_put(in_dev); > } > @@ -744,7 +754,7 @@ static void igmp_timer_expire(unsigned long data) > > if (im->unsolicit_count) { > im->unsolicit_count--; > - igmp_start_timer(im, IGMP_Unsolicited_Report_Interval); > + igmp_start_timer(im, unsolicited_report_interval(in_dev)); > } > im->reporter = 1; > spin_unlock(&im->lock); > -- > 1.7.10.4 -- "Thought is the essence of where you are now."