net: add an ioctl to get a socket network namespace

Each socket operates in a network namespace where it has been created, so if we want to dump and restore a socket, we have to know its network namespace. We have a socket_diag to get information about sockets, it doesn't report sockets which are not bound or connected. This patch introduces a new socket ioctl, which is called SIOCGSKNS and used to get a file descriptor for a socket network namespace. A task must have CAP_NET_ADMIN in a target network namespace to use this ioctl.

Andrey Vagin committed 10 years ago

Commit c62cce21 parent 2a43ca04 files · +19 −1Browse files

Unified · Split

4 files

fs/nsfs.c +1 −1
include/linux/proc_fs.h +4 −0
include/uapi/linux/sockios.h +1 −0
net/socket.c +13 −0

fs/nsfs.c+1−1

@@ -118,7 +118,7 @@ again: · 117 unmodified lines
118	118	return ret;
119	119	}
120	120
121		−static int open_related_ns(struct ns_common *ns,
	121	+int open_related_ns(struct ns_common *ns,
122	122	struct ns_common (get_ns)(struct ns_common *ns))
123	123	{
124	124	struct path path = {};

include/linux/proc_fs.h+4−0

@@ -82,4 +82,8 @@ static inline struct proc_dir_entry *proc_net_mkdir( · 81 unmodified lines
82	82	return proc_mkdir_data(name, 0, parent, net);
83	83	}
84	84
	85	+struct ns_common;
	86	+int open_related_ns(struct ns_common *ns,
	87	+ struct ns_common (get_ns)(struct ns_common *ns));
	88	+
85	89	#endif /* _LINUX_PROC_FS_H */

include/uapi/linux/sockios.h+1−0

@@ -84,6 +84,7 @@ · 83 unmodified lines
84	84	#define SIOCWANDEV 0x894A /* get/set netdev parameters */
85	85
86	86	#define SIOCOUTQNSD 0x894B /* output queue size (not sent only) */
	87	+#define SIOCGSKNS 0x894C /* get socket network namespace */
87	88
88	89	/* ARP cache control calls. */
89	90	/* 0x8950 - 0x8952 * obsolete calls, don't re-use */

net/socket.c+13−0

@@ -877,6 +877,11 @@ static long sock_do_ioctl(struct net net, struct socket sock, · 876 unmodified lines
877	877	* what to do with it - that's up to the protocol still.
878	878	*/
879	879
	880	+static struct ns_common get_net_ns(struct ns_common ns)
	881	+{
	882	+ return &get_net(container_of(ns, struct net, ns))->ns;
	883	+}
	884	+
880	885	static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg)
881	886	{
882	887	struct socket *sock;
@@ -945,6 +950,13 @@ static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg) · 62 unmodified lines
945	950	err = dlci_ioctl_hook(cmd, argp);
946	951	mutex_unlock(&dlci_ioctl_mutex);
947	952	break;
	953	+ case SIOCGSKNS:
	954	+ err = -EPERM;
	955	+ if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
	956	+ break;
	957	+
	958	+ err = open_related_ns(&net->ns, get_net_ns);
	959	+ break;
948	960	default:
949	961	err = sock_do_ioctl(net, sock, cmd, arg);
950	962	break;
@@ -3093,6 +3105,7 @@ static int compat_sock_ioctl_trans(struct file file, struct socket sock, · 2142 unmodified lines
3093	3105	case SIOCSIFVLAN:
3094	3106	case SIOCADDDLCI:
3095	3107	case SIOCDELDLCI:
	3108	+ case SIOCGSKNS:
3096	3109	return sock_ioctl(file, cmd, arg);
3097	3110
3098	3111	case SIOCGIFFLAGS: