[PATCH 3.2 086/126] igmp: do not remove igmp souce list info when set link down

[Ben Hutchings]

3.2.85-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Hangbin Liu <liuhang...@gmail.com>

commit 24803f38a5c0b6c57ed800b47e695f9ce474bc3a upstream.

In commit 24cf3af3fed5 ("igmp: call ip_mc_clear_src..."), we forgot to remove
igmpv3_clear_delrec() in ip_mc_down(), which also called ip_mc_clear_src().
This make us clear all IGMPv3 source filter info after NETDEV_DOWN.
Move igmpv3_clear_delrec() to ip_mc_destroy_dev() and then no need
ip_mc_clear_src() in ip_mc_destroy_dev().

On the other hand, we should restore back instead of free all source filter
info in igmpv3_del_delrec(). Or we will not able to restore IGMPv3 source
filter info after NETDEV_UP and NETDEV_POST_TYPE_CHANGE.

Fixes: 24cf3af3fed5 ("igmp: call ip_mc_clear_src() only when ...")
Signed-off-by: Hangbin Liu <liuhang...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
[bwh: Backported to 3.2:
 - Use IGMP_Unsolicited_Report_Count instead of sysctl_igmp_qrv
 - Adjust context]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -140,7 +140,7 @@
          time_before(jiffies, (in_dev)->mr_v2_seen)))
 
 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_del_delrec(struct in_device *in_dev, struct ip_mc_list *im);
 static void igmpv3_clear_delrec(struct in_device *in_dev);
 static int sf_setstate(struct ip_mc_list *pmc);
 static void sf_markstate(struct ip_mc_list *pmc);
@@ -1077,10 +1077,14 @@ static void igmpv3_add_delrec(struct in_
        spin_unlock_bh(&in_dev->mc_tomb_lock);
 }
 
-static void igmpv3_del_delrec(struct in_device *in_dev, __be32 multiaddr)
+/*
+ * restore ip_mc_list deleted records
+ */
+static void igmpv3_del_delrec(struct in_device *in_dev, struct ip_mc_list *im)
 {
        struct ip_mc_list *pmc, *pmc_prev;
-       struct ip_sf_list *psf, *psf_next;
+       struct ip_sf_list *psf;
+       __be32 multiaddr = im->multiaddr;
 
        spin_lock_bh(&in_dev->mc_tomb_lock);
        pmc_prev = NULL;
@@ -1096,16 +1100,26 @@ static void igmpv3_del_delrec(struct in_
                        in_dev->mc_tomb = pmc->next;
        }
        spin_unlock_bh(&in_dev->mc_tomb_lock);
+
+       spin_lock_bh(&im->lock);
        if (pmc) {
-               for (psf=pmc->tomb; psf; psf=psf_next) {
-                       psf_next = psf->sf_next;
-                       kfree(psf);
+               im->interface = pmc->interface;
+               im->crcount = in_dev->mr_qrv ?: IGMP_Unsolicited_Report_Count;
+               im->sfmode = pmc->sfmode;
+               if (pmc->sfmode == MCAST_INCLUDE) {
+                       im->tomb = pmc->tomb;
+                       im->sources = pmc->sources;
+                       for (psf = im->sources; psf; psf = psf->sf_next)
+                               psf->sf_crcount = im->crcount;
                }
                in_dev_put(pmc->interface);
-               kfree(pmc);
        }
+       spin_unlock_bh(&im->lock);
 }
 
+/*
+ * flush ip_mc_list deleted records
+ */
 static void igmpv3_clear_delrec(struct in_device *in_dev)
 {
        struct ip_mc_list *pmc, *nextpmc;
@@ -1250,7 +1264,7 @@ void ip_mc_inc_group(struct in_device *i
        rcu_assign_pointer(in_dev->mc_list, im);
 
 #ifdef CONFIG_IP_MULTICAST
-       igmpv3_del_delrec(in_dev, im->multiaddr);
+       igmpv3_del_delrec(in_dev, im);
 #endif
        igmp_group_added(im);
        if (!in_dev->dead)
@@ -1340,8 +1354,12 @@ void ip_mc_remap(struct in_device *in_de
 
        ASSERT_RTNL();
 
-       for_each_pmc_rtnl(in_dev, pmc)
+       for_each_pmc_rtnl(in_dev, pmc) {
+#ifdef CONFIG_IP_MULTICAST
+               igmpv3_del_delrec(in_dev, pmc);
+#endif
                igmp_group_added(pmc);
+       }
 }
 
 /* Device going down */
@@ -1362,7 +1380,6 @@ void ip_mc_down(struct in_device *in_dev
        in_dev->mr_gq_running = 0;
        if (del_timer(&in_dev->mr_gq_timer))
                __in_dev_put(in_dev);
-       igmpv3_clear_delrec(in_dev);
 #endif
 
        ip_mc_dec_group(in_dev, IGMP_ALL_HOSTS);
@@ -1397,8 +1414,12 @@ void ip_mc_up(struct in_device *in_dev)
 
        ip_mc_inc_group(in_dev, IGMP_ALL_HOSTS);
 
-       for_each_pmc_rtnl(in_dev, pmc)
+       for_each_pmc_rtnl(in_dev, pmc) {
+#ifdef CONFIG_IP_MULTICAST
+               igmpv3_del_delrec(in_dev, pmc);
+#endif
                igmp_group_added(pmc);
+       }
 }
 
 /*
@@ -1413,13 +1434,13 @@ void ip_mc_destroy_dev(struct in_device
 
        /* Deactivate timers */
        ip_mc_down(in_dev);
+#ifdef CONFIG_IP_MULTICAST
+       igmpv3_clear_delrec(in_dev);
+#endif
 
        while ((i = rtnl_dereference(in_dev->mc_list)) != NULL) {
                in_dev->mc_list = i->next_rcu;
                in_dev->mc_count--;
-
-               /* We've dropped the groups in ip_mc_down already */
-               ip_mc_clear_src(i);
                ip_ma_put(i);
        }
 }