Merge branch 'ip_level_multicast_join_leave'

Madhu Challa says:

====================
Multicast group join/leave at ip level

This series enables configuring multicast group join/leave at ip level
by extending the "ip address" command.

It adds a new control socket mc_autojoin_sock and ifa_flag IFA_F_MCAUTOJOIN
to invoke the corresponding igmp group join/leave api.

Since the igmp group join/leave api takes the rtnl_lock the code had to
be refactored by adding a shim layer prefixed by __ that can be invoked
by code that already has the rtnl_lock. This way we avoid proliferation of
work queues.

The first patch in this series does the refactoring for igmp v6.
Its based on igmp v4 changes that were added by Eric Dumazet.

The second patch in this series does the group join/leave based on the
setting of the IFA_F_MCAUTOJOIN flag.

v5:
- addressed comments from Daniel Borkmann.
 - removed blank line in patch 1/2
 - removed unused variable, const arg in patch 2/2
v4:
- addressed comments from Yoshifuji Hideaki.
 - Remove WARN_ON not needed because we return a value from v2.
- addressed comments from Daniel Borkmann.
 - rename sock to mc_autojoin_sk
 - ip_mc_config() pass ifa so it needs one less argument.
 - igmp_net_{init|destroy}() use inet_ctl_sock_{create|destroy}
 - inet_rtm_newaddr() change scope of ret.
 - igmp_net_init() no need to initialize sock to NULL.
v3:
- addressed comments from David Miller.
 - fixed indentation and local variable order.
v2:
- addressed comments from Eric Dumazet.
 - removed workqueue and call __ip_mc_{join|leave}_group or
   __ipv6_sock_mc_{join|drop}
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 126 insertions, 16 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 3a8985c94581..5105759e4e00 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -548,6 +548,26 @@ struct in_ifaddr *inet_ifa_byprefix(struct in_device *in_dev, __be32 prefix,
 	return NULL;
 }
 
+static int ip_mc_config(struct sock *sk, bool join, const struct in_ifaddr *ifa)
+{
+	struct ip_mreqn mreq = {
+		.imr_multiaddr.s_addr = ifa->ifa_address,
+		.imr_ifindex = ifa->ifa_dev->dev->ifindex,
+	};
+	int ret;
+
+	ASSERT_RTNL();
+
+	lock_sock(sk);
+	if (join)
+		ret = __ip_mc_join_group(sk, &mreq);
+	else
+		ret = __ip_mc_leave_group(sk, &mreq);
+	release_sock(sk);
+
+	return ret;
+}
+
 static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct net *net = sock_net(skb->sk);
@@ -584,6 +604,8 @@ static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh)
 		    !inet_ifa_match(nla_get_be32(tb[IFA_ADDRESS]), ifa)))
 			continue;
 
+		if (ipv4_is_multicast(ifa->ifa_address))
+			ip_mc_config(net->ipv4.mc_autojoin_sk, false, ifa);
 		__inet_del_ifa(in_dev, ifap, 1, nlh, NETLINK_CB(skb).portid);
 		return 0;
 	}
@@ -838,6 +860,15 @@ static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
 		 * userspace already relies on not having to provide this.
 		 */
 		set_ifa_lifetime(ifa, valid_lft, prefered_lft);
+		if (ifa->ifa_flags & IFA_F_MCAUTOJOIN) {
+			int ret = ip_mc_config(net->ipv4.mc_autojoin_sk,
+					       true, ifa);
+
+			if (ret < 0) {
+				inet_free_ifa(ifa);
+				return ret;
+			}
+		}
 		return __inet_insert_ifa(ifa, nlh, NETLINK_CB(skb).portid);
 	} else {
 		inet_free_ifa(ifa);
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 4b1172d73e03..5cb1ef4ce292 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -97,6 +97,7 @@
 #include <net/route.h>
 #include <net/sock.h>
 #include <net/checksum.h>
+#include <net/inet_common.h>
 #include <linux/netfilter_ipv4.h>
 #ifdef CONFIG_IP_MROUTE
 #include <linux/mroute.h>
@@ -2740,6 +2741,7 @@ static const struct file_operations igmp_mcf_seq_fops = {
 static int __net_init igmp_net_init(struct net *net)
 {
 	struct proc_dir_entry *pde;
+	int err;
 
 	pde = proc_create("igmp", S_IRUGO, net->proc_net, &igmp_mc_seq_fops);
 	if (!pde)
@@ -2748,8 +2750,18 @@ static int __net_init igmp_net_init(struct net *net)
 			  &igmp_mcf_seq_fops);
 	if (!pde)
 		goto out_mcfilter;
+	err = inet_ctl_sock_create(&net->ipv4.mc_autojoin_sk, AF_INET,
+				   SOCK_DGRAM, 0, net);
+	if (err < 0) {
+		pr_err("Failed to initialize the IGMP autojoin socket (err %d)\n",
+		       err);
+		goto out_sock;
+	}
+
 	return 0;
 
+out_sock:
+	remove_proc_entry("mcfilter", net->proc_net);
 out_mcfilter:
 	remove_proc_entry("igmp", net->proc_net);
 out_igmp:
@@ -2760,6 +2772,7 @@ static void __net_exit igmp_net_exit(struct net *net)
 {
 	remove_proc_entry("mcfilter", net->proc_net);
 	remove_proc_entry("igmp", net->proc_net);
+	inet_ctl_sock_destroy(net->ipv4.mc_autojoin_sk);
 }
 
 static struct pernet_operations igmp_net_ops = {
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 98e4a63d72bb..783bccfcc060 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2464,6 +2464,23 @@ err_exit:
 	return err;
 }
 
+static int ipv6_mc_config(struct sock *sk, bool join,
+			  const struct in6_addr *addr, int ifindex)
+{
+	int ret;
+
+	ASSERT_RTNL();
+
+	lock_sock(sk);
+	if (join)
+		ret = __ipv6_sock_mc_join(sk, ifindex, addr);
+	else
+		ret = __ipv6_sock_mc_drop(sk, ifindex, addr);
+	release_sock(sk);
+
+	return ret;
+}
+
 /*
  *	Manual configuration of address on an interface
  */
@@ -2476,10 +2493,10 @@ static int inet6_addr_add(struct net *net, int ifindex,
 	struct inet6_ifaddr *ifp;
 	struct inet6_dev *idev;
 	struct net_device *dev;
+	unsigned long timeout;
+	clock_t expires;
 	int scope;
 	u32 flags;
-	clock_t expires;
-	unsigned long timeout;
 
 	ASSERT_RTNL();
 
@@ -2501,6 +2518,14 @@ static int inet6_addr_add(struct net *net, int ifindex,
 	if (IS_ERR(idev))
 		return PTR_ERR(idev);
 
+	if (ifa_flags & IFA_F_MCAUTOJOIN) {
+		int ret = ipv6_mc_config(net->ipv6.mc_autojoin_sk,
+					 true, pfx, ifindex);
+
+		if (ret < 0)
+			return ret;
+	}
+
 	scope = ipv6_addr_scope(pfx);
 
 	timeout = addrconf_timeout_fixup(valid_lft, HZ);
@@ -2542,6 +2567,9 @@ static int inet6_addr_add(struct net *net, int ifindex,
 		in6_ifa_put(ifp);
 		addrconf_verify_rtnl();
 		return 0;
+	} else if (ifa_flags & IFA_F_MCAUTOJOIN) {
+		ipv6_mc_config(net->ipv6.mc_autojoin_sk,
+			       false, pfx, ifindex);
 	}
 
 	return PTR_ERR(ifp);
@@ -2578,6 +2606,10 @@ static int inet6_addr_del(struct net *net, int ifindex, u32 ifa_flags,
 						 jiffies);
 			ipv6_del_addr(ifp);
 			addrconf_verify_rtnl();
+			if (ipv6_addr_is_multicast(pfx)) {
+				ipv6_mc_config(net->ipv6.mc_autojoin_sk,
+					       false, pfx, dev->ifindex);
+			}
 			return 0;
 		}
 	}
@@ -3945,7 +3977,7 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 	/* We ignore other flags so far. */
 	ifa_flags &= IFA_F_NODAD | IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR |
-		     IFA_F_NOPREFIXROUTE;
+		     IFA_F_NOPREFIXROUTE | IFA_F_MCAUTOJOIN;
 
 	ifa = ipv6_get_ifaddr(net, pfx, dev, 1);
 	if (ifa == NULL) {
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 5ce107c8aab3..1dd1fedff9f4 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -132,7 +132,7 @@ static int unsolicited_report_interval(struct inet6_dev *idev)
 	return iv > 0 ? iv : 1;
 }
 
-int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
+int __ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
 {
 	struct net_device *dev = NULL;
 	struct ipv6_mc_socklist *mc_lst;
@@ -140,6 +140,8 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
 	struct net *net = sock_net(sk);
 	int err;
 
+	ASSERT_RTNL();
+
 	if (!ipv6_addr_is_multicast(addr))
 		return -EINVAL;
 
@@ -161,7 +163,6 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
 	mc_lst->next = NULL;
 	mc_lst->addr = *addr;
 
-	rtnl_lock();
 	if (ifindex == 0) {
 		struct rt6_info *rt;
 		rt = rt6_lookup(net, addr, NULL, 0, 0);
@@ -173,7 +174,6 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
 		dev = __dev_get_by_index(net, ifindex);
 
 	if (dev == NULL) {
-		rtnl_unlock();
 		sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
 		return -ENODEV;
 	}
@@ -190,7 +190,6 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
 	err = ipv6_dev_mc_inc(dev, addr);
 
 	if (err) {
-		rtnl_unlock();
 		sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
 		return err;
 	}
@@ -198,25 +197,37 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
 	mc_lst->next = np->ipv6_mc_list;
 	rcu_assign_pointer(np->ipv6_mc_list, mc_lst);
 
+	return 0;
+}
+EXPORT_SYMBOL(__ipv6_sock_mc_join);
+
+int ipv6_sock_mc_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
+{
+	int ret;
+
+	rtnl_lock();
+	ret = __ipv6_sock_mc_join(sk, ifindex, addr);
 	rtnl_unlock();
 
-	return 0;
+	return ret;
 }
+EXPORT_SYMBOL(ipv6_sock_mc_join);
 
 /*
  *	socket leave on multicast group
  */
-int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
+int __ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct ipv6_mc_socklist *mc_lst;
 	struct ipv6_mc_socklist __rcu **lnk;
 	struct net *net = sock_net(sk);
 
+	ASSERT_RTNL();
+
 	if (!ipv6_addr_is_multicast(addr))
 		return -EINVAL;
 
-	rtnl_lock();
 	for (lnk = &np->ipv6_mc_list;
 	     (mc_lst = rtnl_dereference(*lnk)) != NULL;
 	      lnk = &mc_lst->next) {
@@ -235,17 +246,28 @@ int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
 					__ipv6_dev_mc_dec(idev, &mc_lst->addr);
 			} else
 				(void) ip6_mc_leave_src(sk, mc_lst, NULL);
-			rtnl_unlock();
 
 			atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc);
 			kfree_rcu(mc_lst, rcu);
 			return 0;
 		}
 	}
-	rtnl_unlock();
 
 	return -EADDRNOTAVAIL;
 }
+EXPORT_SYMBOL(__ipv6_sock_mc_drop);
+
+int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
+{
+	int ret;
+
+	rtnl_lock();
+	ret = __ipv6_sock_mc_drop(sk, ifindex, addr);
+	rtnl_unlock();
+
+	return ret;
+}
+EXPORT_SYMBOL(ipv6_sock_mc_drop);
 
 /* called with rcu_read_lock() */
 static struct inet6_dev *ip6_mc_find_dev_rcu(struct net *net,
@@ -2907,20 +2929,32 @@ static int __net_init igmp6_net_init(struct net *net)
 
 	inet6_sk(net->ipv6.igmp_sk)->hop_limit = 1;
 
+	err = inet_ctl_sock_create(&net->ipv6.mc_autojoin_sk, PF_INET6,
+				   SOCK_RAW, IPPROTO_ICMPV6, net);
+	if (err < 0) {
+		pr_err("Failed to initialize the IGMP6 autojoin socket (err %d)\n",
+		       err);
+		goto out_sock_create;
+	}
+
 	err = igmp6_proc_init(net);
 	if (err)
-		goto out_sock_create;
-out:
-	return err;
+		goto out_sock_create_autojoin;
 
+	return 0;
+
+out_sock_create_autojoin:
+	inet_ctl_sock_destroy(net->ipv6.mc_autojoin_sk);
 out_sock_create:
 	inet_ctl_sock_destroy(net->ipv6.igmp_sk);
-	goto out;
+out:
+	return err;
 }
 
 static void __net_exit igmp6_net_exit(struct net *net)
 {
 	inet_ctl_sock_destroy(net->ipv6.igmp_sk);
+	inet_ctl_sock_destroy(net->ipv6.mc_autojoin_sk);
 	igmp6_proc_exit(net);
 }