On Fri, Jan 19, 2007 at 04:47:19PM +0100, dlezcano@fr.ibm.com wrote:
> 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   */
							   ~~~ from
> +
>  /* 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.

hmm, sounds like the address is moved between the
namespaces? does that mean that the 'parent' will
not see the 'isolated' ip anymore?

TIA,
Herbert

> + * @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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