From: Daniel Lezcano <dlezcano@fr.ibm.com>

New ioctl to "push" ifaddr to a container. Actually, the push is done
from the current namespace, so the right word is "pull". That will be
changed to move ifaddr from l2 network namespace to l3.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

---
 include/linux/net_namespace.h |    7 ++
 include/linux/sockios.h       |    4 +
 net/core/net_namespace.c      |  118 +++++++++++++++++++++++++++++++++++++++++-
 net/ipv4/af_inet.c            |    4 +
 4 files changed, 132 insertions(+), 1 deletion(-)

Index: 2.6.20-rc4-mm1/include/linux/sockios.h
===================================================================
--- 2.6.20-rc4-mm1.orig/include/linux/sockios.h
+++ 2.6.20-rc4-mm1/include/linux/sockios.h
@@ -122,6 +122,10 @@
 #define SIOCBRADDIF	0x89a2		/* add interface to bridge      */
 #define SIOCBRDELIF	0x89a3		/* remove interface from bridge */
 
+/* Container calls */
+#define SIOCNETNSPUSHIF  0x89b0         /* add ifaddr to namespace      */
+#define SIOCNETNSPULLIF  0x89b1         /* remove ifaddr to namespace   */
+
 /* Device private ioctl calls */
 
 /*
Index: 2.6.20-rc4-mm1/net/ipv4/af_inet.c
===================================================================
--- 2.6.20-rc4-mm1.orig/net/ipv4/af_inet.c
+++ 2.6.20-rc4-mm1/net/ipv4/af_inet.c
@@ -789,6 +789,10 @@
 		case SIOCSIFFLAGS:
 			err = devinet_ioctl(cmd, (void __user *)arg);
 			break;
+	        case SIOCNETNSPUSHIF:
+	        case SIOCNETNSPULLIF:
+			err = net_ns_ioctl(cmd, (void __user *)arg);
+			break;
 		default:
 			if (sk->sk_prot->ioctl)
 				err = sk->sk_prot->ioctl(sk, cmd, arg);
Index: 2.6.20-rc4-mm1/include/linux/net_namespace.h
===================================================================
--- 2.6.20-rc4-mm1.orig/include/linux/net_namespace.h
+++ 2.6.20-rc4-mm1/include/linux/net_namespace.h
@@ -91,6 +91,8 @@
 
 #define net_ns_hash(ns)			((ns)->hash)
 
+extern int net_ns_ioctl(unsigned int cmd, void __user *arg);
+
 #else /* CONFIG_NET_NS */
 
 #define INIT_NET_NS(net_ns)
@@ -141,6 +143,11 @@
 
 #define net_ns_hash(ns)			(0)
 
+static inline int net_ns_ioctl(unsigned int cmd, void __user *arg)
+{
+	return -ENOSYS;
+}
+
 #endif /* !CONFIG_NET_NS */
 
 #endif /* _LINUX_NET_NAMESPACE_H */
Index: 2.6.20-rc4-mm1/net/core/net_namespace.c
===================================================================
--- 2.6.20-rc4-mm1.orig/net/core/net_namespace.c
+++ 2.6.20-rc4-mm1/net/core/net_namespace.c
@@ -10,7 +10,9 @@
 #include <linux/nsproxy.h>
 #include <linux/net_namespace.h>
 #include <linux/net.h>
+#include <linux/in.h>
 #include <linux/netdevice.h>
+#include <linux/inetdevice.h>
 #include <net/ip_fib.h>
 
 struct net_namespace init_net_ns = {
@@ -123,6 +125,33 @@
 	return err;
 }
 
+/*
+ * The function will move the ifaddr to the l2 network namespace
+ * parent.
+ * @net_ns: the related network namespace
+ */
+static void release_ifa_to_parent(const struct net_namespace* net_ns)
+{
+	struct net_device *dev;
+	struct in_device *in_dev;
+
+	read_lock(&dev_base_lock);
+	rcu_read_lock();
+	for (dev = dev_base; dev; dev = dev->next) {
+		in_dev = __in_dev_get_rcu(dev);
+		if (!in_dev)
+			continue;
+
+		for_ifa(in_dev) {
+			if (ifa->ifa_net_ns != net_ns)
+				continue;
+			ifa->ifa_net_ns = net_ns->parent;
+		} endfor_ifa(in_dev);
+	}
+	read_unlock(&dev_base_lock);
+	rcu_read_unlock();
+}
+
 void free_net_ns(struct kref *kref)
 {
 	struct net_namespace *ns;
@@ -139,12 +168,99 @@
 		}
 	}
 
-	if (ns->level == NET_NS_LEVEL3)
+	if (ns->level == NET_NS_LEVEL3) {
+		release_ifa_to_parent(ns);
 		put_net_ns(ns->parent);
+	}
 
 	printk(KERN_DEBUG "NET_NS: net namespace %p destroyed\n", ns);
 	kfree(ns);
 }
 EXPORT_SYMBOL_GPL(free_net_ns);
 
+/*
+ * This function allows to assign an IP address from a l2 network
+ * namespace to one of his l3 child or to release from an l3 network
+ * namespace to his l2 network namespace parent.
+ * @cmd: a "push" / "pull" command
+ * @arg: an userspace buffer containing an ifreq structure
+ * Returns:
+ * - EPERM : if caller has no CAP_NET_ADMIN capabilities or the
+ *           current level of network namespace is not layer 2
+ * - EFAULT : if arg is an invalid buffer
+ * - EADDRNOTAVAIL : if the specified ifaddr does not exists
+ * - EINVAL : if cmd is unknown
+ * - zero on success
+ */
+int net_ns_ioctl(unsigned int cmd, void __user *arg)
+{
+	struct ifreq ifr;
+	struct sockaddr_in *sin = (struct sockaddr_in *)&ifr.ifr_addr;
+	struct net_namespace *net_ns = current_net_ns;
+	struct net_device *dev;
+	struct in_device *in_dev;
+	struct in_ifaddr **ifap = NULL;
+	struct in_ifaddr *ifa = NULL;
+	char *colon;
+	int err;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	if (net_ns->level != NET_NS_LEVEL3)
+		return -EPERM;
+
+	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
+		return -EFAULT;
+
+	ifr.ifr_name[IFNAMSIZ - 1] = 0;
+
+
+	colon = strchr(ifr.ifr_name, ':');
+	if (colon)
+		*colon = 0;
+
+	rtnl_lock();
+
+	err = -ENODEV;
+	dev = __dev_get_by_name(ifr.ifr_name);
+	if (!dev)
+		goto out;
+
+	if (colon)
+		*colon = ':';
+
+	err = -EADDRNOTAVAIL;
+	in_dev = __in_dev_get_rtnl(dev);
+	if (!in_dev)
+		goto out;
+
+	for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
+	     ifap = &ifa->ifa_next)
+		if (!strcmp(ifr.ifr_name, ifa->ifa_label) &&
+		    sin->sin_addr.s_addr == ifa->ifa_local)
+			break;
+	if (!ifa)
+		goto out;
+
+	err = -EINVAL;
+	switch(cmd) {
+
+	case SIOCNETNSPUSHIF:
+		ifa->ifa_net_ns = net_ns;
+		break;
+
+	case SIOCNETNSPULLIF:
+		ifa->ifa_net_ns = net_ns->parent;
+		break;
+	default:
+		goto out;
+	}
+
+	err = 0;
+out:
+	rtnl_unlock();
+	return err;
+}
+
 #endif /* CONFIG_NET_NS */

-- 
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