[PATCH] ipmr: ip6mr: Create new sockopt to clear mfc cache only

[Callum Sinclair <callum.sinclair@alliedtelesis.co.nz>]

Currently the only way to clear the mfc cache was to delete the entries
one by one using the MRT_DEL_MFC socket option or to destroy and
recreate the socket.

Create a new socket option which will clear the multicast forwarding
cache on the socket without destroying the socket.

Signed-off-by: Callum Sinclair <callum.sinclair@alliedtelesis.co.nz>
---
 include/uapi/linux/mroute.h  |  7 +++-
 include/uapi/linux/mroute6.h |  7 +++-
 net/ipv4/ipmr.c              | 69 +++++++++++++++++++++-------------
 net/ipv6/ip6mr.c             | 73 ++++++++++++++++++++++--------------
 4 files changed, 99 insertions(+), 57 deletions(-)

diff --git a/include/uapi/linux/mroute.h b/include/uapi/linux/mroute.h
index 5d37a9ccce63..2d475edc3ec3 100644
--- a/include/uapi/linux/mroute.h
+++ b/include/uapi/linux/mroute.h
@@ -28,12 +28,17 @@
 #define MRT_TABLE	(MRT_BASE+9)	/* Specify mroute table ID		*/
 #define MRT_ADD_MFC_PROXY	(MRT_BASE+10)	/* Add a (*,*|G) mfc entry	*/
 #define MRT_DEL_MFC_PROXY	(MRT_BASE+11)	/* Del a (*,*|G) mfc entry	*/
-#define MRT_MAX		(MRT_BASE+11)
+#define MRT_FLUSH	(MRT_BASE+12)	/* Flush all multicast entries and vifs	*/
+#define MRT_MAX		(MRT_BASE+12)
 
 #define SIOCGETVIFCNT	SIOCPROTOPRIVATE	/* IP protocol privates */
 #define SIOCGETSGCNT	(SIOCPROTOPRIVATE+1)
 #define SIOCGETRPF	(SIOCPROTOPRIVATE+2)
 
+/* Flags used for MRT_FLUSH */
+#define MRT_FLUSH_ENTRIES	1	/* For flushing all multicast entries */
+#define MRT_FLUSH_VIFS		2	/* For flushing all multicast vifs */
+
 #define MAXVIFS		32
 typedef unsigned long vifbitmap_t;	/* User mode code depends on this lot */
 typedef unsigned short vifi_t;
diff --git a/include/uapi/linux/mroute6.h b/include/uapi/linux/mroute6.h
index 9999cc006390..b04094d997c8 100644
--- a/include/uapi/linux/mroute6.h
+++ b/include/uapi/linux/mroute6.h
@@ -31,12 +31,17 @@
 #define MRT6_TABLE	(MRT6_BASE+9)	/* Specify mroute table ID		*/
 #define MRT6_ADD_MFC_PROXY	(MRT6_BASE+10)	/* Add a (*,*|G) mfc entry	*/
 #define MRT6_DEL_MFC_PROXY	(MRT6_BASE+11)	/* Del a (*,*|G) mfc entry	*/
-#define MRT6_MAX	(MRT6_BASE+11)
+#define MRT6_FLUSH	(MRT6_BASE+12)	/* Flush all multicast entries and vifs	*/
+#define MRT6_MAX	(MRT6_BASE+12)
 
 #define SIOCGETMIFCNT_IN6	SIOCPROTOPRIVATE	/* IP protocol privates */
 #define SIOCGETSGCNT_IN6	(SIOCPROTOPRIVATE+1)
 #define SIOCGETRPF	(SIOCPROTOPRIVATE+2)
 
+/* Flags used for MRT6_FLUSH*/
+#define MRT6_FLUSH_ENTRIES	1	/* For flushing all multicast entries */
+#define MRT6_FLUSH_VIFS		2	/* For flushing all multicast vifs */
+
 #define MAXMIFS		32
 typedef unsigned long mifbitmap_t;	/* User mode code depends on this lot */
 typedef unsigned short mifi_t;
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index ddbf8c9a1abb..2eb569138569 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -416,7 +416,7 @@ static struct mr_table *ipmr_new_table(struct net *net, u32 id)
 static void ipmr_free_table(struct mr_table *mrt)
 {
 	del_timer_sync(&mrt->ipmr_expire_timer);
-	mroute_clean_tables(mrt, true);
+	mroute_clean_tables(mrt, true, MRT_FLUSH_VIFS | MRT_FLUSH_ENTRIES);
 	rhltable_destroy(&mrt->mfc_hash);
 	kfree(mrt);
 }
@@ -1299,44 +1299,48 @@ static int ipmr_mfc_add(struct net *net, struct mr_table *mrt,
 }
 
 /* Close the multicast socket, and clear the vif tables etc */
-static void mroute_clean_tables(struct mr_table *mrt, bool all)
+static void mroute_clean_tables(struct mr_table *mrt, bool all, int flags)
 {
 	struct net *net = read_pnet(&mrt->net);
-	struct mr_mfc *c, *tmp;
 	struct mfc_cache *cache;
+	struct mr_mfc *c, *tmp;
 	LIST_HEAD(list);
 	int i;
 
 	/* Shut down all active vif entries */
-	for (i = 0; i < mrt->maxvif; i++) {
-		if (!all && (mrt->vif_table[i].flags & VIFF_STATIC))
-			continue;
-		vif_delete(mrt, i, 0, &list);
+	if (flags & MRT_FLUSH_VIFS) {
+		for (i = 0; i < mrt->maxvif; i++) {
+			if (!all && (mrt->vif_table[i].flags & VIFF_STATIC))
+				continue;
+				vif_delete(mrt, i, 0, &list);
+		}
+		unregister_netdevice_many(&list);
 	}
-	unregister_netdevice_many(&list);
 
 	/* Wipe the cache */
-	list_for_each_entry_safe(c, tmp, &mrt->mfc_cache_list, list) {
-		if (!all && (c->mfc_flags & MFC_STATIC))
-			continue;
-		rhltable_remove(&mrt->mfc_hash, &c->mnode, ipmr_rht_params);
-		list_del_rcu(&c->list);
-		cache = (struct mfc_cache *)c;
-		call_ipmr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, cache,
-					      mrt->id);
-		mroute_netlink_event(mrt, cache, RTM_DELROUTE);
-		mr_cache_put(c);
-	}
-
-	if (atomic_read(&mrt->cache_resolve_queue_len) != 0) {
-		spin_lock_bh(&mfc_unres_lock);
-		list_for_each_entry_safe(c, tmp, &mrt->mfc_unres_queue, list) {
-			list_del(&c->list);
+	if (flags & MRT_FLUSH_ENTRIES) {
+		list_for_each_entry_safe(c, tmp, &mrt->mfc_cache_list, list) {
+			if (!all && (c->mfc_flags & MFC_STATIC))
+				continue;
+			rhltable_remove(&mrt->mfc_hash, &c->mnode, ipmr_rht_params);
+			list_del_rcu(&c->list);
 			cache = (struct mfc_cache *)c;
+			call_ipmr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, cache,
+										  mrt->id);
 			mroute_netlink_event(mrt, cache, RTM_DELROUTE);
-			ipmr_destroy_unres(mrt, cache);
+			mr_cache_put(c);
+		}
+
+		if (atomic_read(&mrt->cache_resolve_queue_len) != 0) {
+			spin_lock_bh(&mfc_unres_lock);
+			list_for_each_entry_safe(c, tmp, &mrt->mfc_unres_queue, list) {
+				list_del(&c->list);
+				cache = (struct mfc_cache *)c;
+				mroute_netlink_event(mrt, cache, RTM_DELROUTE);
+				ipmr_destroy_unres(mrt, cache);
+			}
+			spin_unlock_bh(&mfc_unres_lock);
 		}
-		spin_unlock_bh(&mfc_unres_lock);
 	}
 }
 
@@ -1357,7 +1361,7 @@ static void mrtsock_destruct(struct sock *sk)
 						    NETCONFA_IFINDEX_ALL,
 						    net->ipv4.devconf_all);
 			RCU_INIT_POINTER(mrt->mroute_sk, NULL);
-			mroute_clean_tables(mrt, false);
+			mroute_clean_tables(mrt, false, MRT_FLUSH_VIFS | MRT_FLUSH_ENTRIES);
 		}
 	}
 	rtnl_unlock();
@@ -1482,6 +1486,17 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval,
 					   sk == rtnl_dereference(mrt->mroute_sk),
 					   parent);
 		break;
+	case MRT_FLUSH:
+		if (get_user(val, (int __user *)optval)) {
+			ret = -EFAULT;
+			break;
+		}
+		rtnl_lock();
+		ipmr_for_each_table(mrt, net) {
+			mroute_clean_tables(mrt, true, val);
+		}
+		rtnl_unlock();
+		break;
 	/* Control PIM assert. */
 	case MRT_ASSERT:
 		if (optlen != sizeof(val)) {
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 30337b38274b..473c83d197fe 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -393,7 +393,7 @@ static struct mr_table *ip6mr_new_table(struct net *net, u32 id)
 static void ip6mr_free_table(struct mr_table *mrt)
 {
 	del_timer_sync(&mrt->ipmr_expire_timer);
-	mroute_clean_tables(mrt, true);
+	mroute_clean_tables(mrt, true, MRT6_FLUSH_VIFS | MRT6_FLUSH_ENTRIES);
 	rhltable_destroy(&mrt->mfc_hash);
 	kfree(mrt);
 }
@@ -1496,43 +1496,47 @@ static int ip6mr_mfc_add(struct net *net, struct mr_table *mrt,
  *	Close the multicast socket, and clear the vif tables etc
  */
 
-static void mroute_clean_tables(struct mr_table *mrt, bool all)
+static void mroute_clean_tables(struct mr_table *mrt, bool all, int flags)
 {
 	struct mr_mfc *c, *tmp;
 	LIST_HEAD(list);
 	int i;
 
 	/* Shut down all active vif entries */
-	for (i = 0; i < mrt->maxvif; i++) {
-		if (!all && (mrt->vif_table[i].flags & VIFF_STATIC))
-			continue;
-		mif6_delete(mrt, i, 0, &list);
+	if (flags & MRT6_FLUSH_VIFS) {
+		for (i = 0; i < mrt->maxvif; i++) {
+			if (!all && (mrt->vif_table[i].flags & VIFF_STATIC))
+				continue;
+			mif6_delete(mrt, i, 0, &list);
+		}
+		unregister_netdevice_many(&list);
 	}
-	unregister_netdevice_many(&list);
 
 	/* Wipe the cache */
-	list_for_each_entry_safe(c, tmp, &mrt->mfc_cache_list, list) {
-		if (!all && (c->mfc_flags & MFC_STATIC))
-			continue;
-		rhltable_remove(&mrt->mfc_hash, &c->mnode, ip6mr_rht_params);
-		list_del_rcu(&c->list);
-		mr6_netlink_event(mrt, (struct mfc6_cache *)c, RTM_DELROUTE);
-		mr_cache_put(c);
-	}
+	if (flags & MRT6_FLUSH_ENTRIES) {
+		list_for_each_entry_safe(c, tmp, &mrt->mfc_cache_list, list) {
+			if (!all && (c->mfc_flags & MFC_STATIC))
+				continue;
+			rhltable_remove(&mrt->mfc_hash, &c->mnode, ip6mr_rht_params);
+			list_del_rcu(&c->list);
+			mr6_netlink_event(mrt, (struct mfc6_cache *)c, RTM_DELROUTE);
+			mr_cache_put(c);
+		}
 
-	if (atomic_read(&mrt->cache_resolve_queue_len) != 0) {
-		spin_lock_bh(&mfc_unres_lock);
-		list_for_each_entry_safe(c, tmp, &mrt->mfc_unres_queue, list) {
-			list_del(&c->list);
-			call_ip6mr_mfc_entry_notifiers(read_pnet(&mrt->net),
-						       FIB_EVENT_ENTRY_DEL,
-						       (struct mfc6_cache *)c,
-						       mrt->id);
-			mr6_netlink_event(mrt, (struct mfc6_cache *)c,
-					  RTM_DELROUTE);
-			ip6mr_destroy_unres(mrt, (struct mfc6_cache *)c);
+		if (atomic_read(&mrt->cache_resolve_queue_len) != 0) {
+			spin_lock_bh(&mfc_unres_lock);
+			list_for_each_entry_safe(c, tmp, &mrt->mfc_unres_queue, list) {
+				list_del(&c->list);
+				call_ip6mr_mfc_entry_notifiers(read_pnet(&mrt->net),
+											   FIB_EVENT_ENTRY_DEL,
+											   (struct mfc6_cache *)c,
+											   mrt->id);
+				mr6_netlink_event(mrt, (struct mfc6_cache *)c,
+						  RTM_DELROUTE);
+				ip6mr_destroy_unres(mrt, (struct mfc6_cache *)c);
+			}
+			spin_unlock_bh(&mfc_unres_lock);
 		}
-		spin_unlock_bh(&mfc_unres_lock);
 	}
 }
 
@@ -1588,7 +1592,7 @@ int ip6mr_sk_done(struct sock *sk)
 						     NETCONFA_IFINDEX_ALL,
 						     net->ipv6.devconf_all);
 
-			mroute_clean_tables(mrt, false);
+			mroute_clean_tables(mrt, false, MRT6_FLUSH_VIFS | MRT6_FLUSH_ENTRIES);
 			err = 0;
 			break;
 		}
@@ -1703,6 +1707,19 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, uns
 					    parent);
 		rtnl_unlock();
 		return ret;
+	case MRT6_DEL_MFC_ALL:
+	{
+		int flags;
+
+		if (get_user(flags, (int __user *)optval))
+			return -EFAULT;
+		rtnl_lock();
+		ip6mr_for_each_table(mrt, net) {
+			mroute_clean_tables(mrt, true, flags);
+		}
+		rtnl_unlock();
+		return 0;
+	}
 
 	/*
 	 *	Control PIM assert (to activate pim will activate assert)
-- 
2.20.1