[PATCH net-next v5 0/2] Multicast group join/leave at ip level

[PATCH net-next v5 0/2] Multicast group join/leave at ip level

[Madhu Challa]

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}

Madhu Challa (2):
  igmp v6: add __ipv6_sock_mc_join and __ipv6_sock_mc_drop
  multicast: Extend ip address command to enable multicast group
    join/leave on

 include/net/ipv6.h           |  8 ++++++
 include/net/netns/ipv4.h     |  1 +
 include/net/netns/ipv6.h     |  1 +
 include/uapi/linux/if_addr.h |  1 +
 net/ipv4/devinet.c           | 31 +++++++++++++++++++++++
 net/ipv4/igmp.c              | 13 ++++++++++
 net/ipv6/addrconf.c          | 38 +++++++++++++++++++++++++---
 net/ipv6/mcast.c             | 60 ++++++++++++++++++++++++++++++++++----------
 8 files changed, 137 insertions(+), 16 deletions(-)

-- 
1.9.1

[PATCH net-next v5 1/2] igmp v6: add __ipv6_sock_mc_join and __ipv6_sock_mc_drop

[Madhu Challa]

Based on the igmp v4 changes from Eric Dumazet.
959d10f6bbf6("igmp: add __ip_mc_{join|leave}_group()")

These changes are needed to perform igmp v6 join/leave while
RTNL is held.

Make ipv6_sock_mc_join and ipv6_sock_mc_drop wrappers around
__ipv6_sock_mc_join and  __ipv6_sock_mc_drop to avoid
proliferation of work queues.

Signed-off-by: Madhu Challa <challa@noironetworks.com>
---
 include/net/ipv6.h |  8 ++++++++
 net/ipv6/mcast.c   | 40 +++++++++++++++++++++++++++++++---------
 2 files changed, 39 insertions(+), 9 deletions(-)

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 4c9fe22..b767306 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -940,4 +940,12 @@ int ipv6_sysctl_register(void);
 void ipv6_sysctl_unregister(void);
 #endif
 
+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);
+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);
 #endif /* _NET_IPV6_H */
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 5ce107c..e4955d0 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,
-- 
1.9.1

[PATCH net-next v5 2/2] multicast: Extend ip address command to enable multicast group join/leave on

[Madhu Challa]

Joining multicast group on ethernet level via "ip maddr" command would
not work if we have an Ethernet switch that does igmp snooping since
the switch would not replicate multicast packets on ports that did not
have IGMP reports for the multicast addresses.

Linux vxlan interfaces created via "ip link add vxlan" have the group option
that enables then to do the required join.

By extending ip address command with option "autojoin" we can get similar
functionality for openvswitch vxlan interfaces as well as other tunneling
mechanisms that need to receive multicast traffic. The kernel code is
structured similar to how the vxlan driver does a group join / leave.

example:
ip address add 224.1.1.10/24 dev eth5 autojoin
ip address del 224.1.1.10/24 dev eth5

Signed-off-by: Madhu Challa <challa@noironetworks.com>
---
 include/net/netns/ipv4.h     |  1 +
 include/net/netns/ipv6.h     |  1 +
 include/uapi/linux/if_addr.h |  1 +
 net/ipv4/devinet.c           | 31 +++++++++++++++++++++++++++++++
 net/ipv4/igmp.c              | 13 +++++++++++++
 net/ipv6/addrconf.c          | 38 +++++++++++++++++++++++++++++++++++---
 net/ipv6/mcast.c             | 20 ++++++++++++++++----
 7 files changed, 98 insertions(+), 7 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index dbe2254..1b26c6c 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -49,6 +49,7 @@ struct netns_ipv4 {
 	struct sock		*fibnl;
 
 	struct sock  * __percpu	*icmp_sk;
+	struct sock		*mc_autojoin_sk;
 
 	struct inet_peer_base	*peers;
 	struct tcpm_hash_bucket	*tcp_metrics_hash;
diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index 69ae41f..ca0db12 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -67,6 +67,7 @@ struct netns_ipv6 {
 	struct sock             *ndisc_sk;
 	struct sock             *tcp_sk;
 	struct sock             *igmp_sk;
+	struct sock		*mc_autojoin_sk;
 #ifdef CONFIG_IPV6_MROUTE
 #ifndef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES
 	struct mr6_table	*mrt6;
diff --git a/include/uapi/linux/if_addr.h b/include/uapi/linux/if_addr.h
index dea10a8..40fdfea 100644
--- a/include/uapi/linux/if_addr.h
+++ b/include/uapi/linux/if_addr.h
@@ -50,6 +50,7 @@ enum {
 #define IFA_F_PERMANENT		0x80
 #define IFA_F_MANAGETEMPADDR	0x100
 #define IFA_F_NOPREFIXROUTE	0x200
+#define IFA_F_MCAUTOJOIN	0x400
 
 struct ifa_cacheinfo {
 	__u32	ifa_prefered;
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 3a8985c..5105759 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 4b1172d..5cb1ef4 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 98e4a63..783bccf 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 e4955d0..1dd1fed 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -2929,20 +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);
 }
 
-- 
1.9.1

Re: [PATCH net-next v5 1/2] igmp v6: add __ipv6_sock_mc_join and __ipv6_sock_mc_drop

[Eric Dumazet]

On Wed, 2015-02-25 at 09:58 -0800, Madhu Challa wrote:
> Based on the igmp v4 changes from Eric Dumazet.
> 959d10f6bbf6("igmp: add __ip_mc_{join|leave}_group()")
> 
> These changes are needed to perform igmp v6 join/leave while
> RTNL is held.
> 
> Make ipv6_sock_mc_join and ipv6_sock_mc_drop wrappers around
> __ipv6_sock_mc_join and  __ipv6_sock_mc_drop to avoid
> proliferation of work queues.
> 
> Signed-off-by: Madhu Challa <challa@noironetworks.com>
> ---

Acked-by: Eric Dumazet <edumazet@google.com>

Re: [PATCH net-next v5 0/2] Multicast group join/leave at ip level

[David Miller]

From: Madhu Challa <challa@noironetworks.com>
Date: Wed, 25 Feb 2015 09:58:33 -0800

> 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.

Applied, but I'm wondering how many hacks we are going to add to the
tree simply because openvswitch does all of it's stuff with non-native
tunneling devices...

Re: [PATCH net-next v5 0/2] Multicast group join/leave at ip level

[Thomas Graf]

On 02/27/15 at 04:26pm, David Miller wrote:
> Applied, but I'm wondering how many hacks we are going to add to the
> tree simply because openvswitch does all of it's stuff with non-native
> tunneling devices...

I hope Jiri's proposed named tunnel socket concept will close the
current scalability gap and allow to merge the paths together again.

Re: [PATCH net-next v5 0/2] Multicast group join/leave at ip level

[Madhu Challa]

On Fri, Feb 27, 2015 at 1:26 PM, David Miller <davem@davemloft.net> wrote:
> From: Madhu Challa <challa@noironetworks.com>
> Date: Wed, 25 Feb 2015 09:58:33 -0800
>
>> 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.
>
> Applied, but I'm wondering how many hacks we are going to add to the
> tree simply because openvswitch does all of it's stuff with non-native
> tunneling devices...

Thanks David. I will look into what Thomas suggested so we can avoid
these workarounds.

Thanks.