[net-next,v2,2/2] tipc: add ioctl to fetch link names

diff --git a/include/uapi/linux/tipc.h b/include/uapi/linux/tipc.h
index 53cd790..6f71b9b 100644
--- a/include/uapi/linux/tipc.h
+++ b/include/uapi/linux/tipc.h
@@ -38,6 +38,7 @@ 
 #define _LINUX_TIPC_H_
 
 #include <linux/types.h>
+#include <linux/sockios.h>
 
 /*
  * TIPC addressing primitives
@@ -207,4 +208,25 @@  struct sockaddr_tipc {
 #define TIPC_NODE_RECVQ_DEPTH	131	/* Default: none (read only) */
 #define TIPC_SOCK_RECVQ_DEPTH	132	/* Default: none (read only) */
 
+/*
+ * Maximum sizes of TIPC bearer-related names (including terminating NULL)
+ * The string formatting for each name element is:
+ * media: media
+ * interface: media:interface name
+ * link: Z.C.N:interface-Z.C.N:interface
+ *
+ */
+
+#define TIPC_MAX_MEDIA_NAME	16
+#define TIPC_MAX_IF_NAME	16
+#define TIPC_MAX_BEARER_NAME	32
+#define TIPC_MAX_LINK_NAME	60
+
+#define SIOCGETLINKNAME		SIOCPROTOPRIVATE
+
+struct tipc_sioc_ln_req {
+	__u32 peer;
+	__u32 bearer_id;
+	char linkname[TIPC_MAX_LINK_NAME];
+};
 #endif
diff --git a/include/uapi/linux/tipc_config.h b/include/uapi/linux/tipc_config.h
index 6b0bff0..41a76ac 100644
--- a/include/uapi/linux/tipc_config.h
+++ b/include/uapi/linux/tipc_config.h
@@ -39,6 +39,7 @@ 
 
 #include <linux/types.h>
 #include <linux/string.h>
+#include <linux/tipc.h>
 #include <asm/byteorder.h>
 
 #ifndef __KERNEL__
@@ -155,15 +156,6 @@ 
 #define TIPC_TLV_PORT_REF	26	/* 32-bit port reference */
 
 /*
- * Maximum sizes of TIPC bearer-related names (including terminating NUL)
- */
-
-#define TIPC_MAX_MEDIA_NAME	16	/* format = media */
-#define TIPC_MAX_IF_NAME	16	/* format = interface */
-#define TIPC_MAX_BEARER_NAME	32	/* format = media:interface */
-#define TIPC_MAX_LINK_NAME	60	/* format = Z.C.N:interface-Z.C.N:interface */
-
-/*
  * Link priority limits (min, default, max, media default)
  */
 
diff --git a/net/tipc/node.c b/net/tipc/node.c
index 3b86a74..1f938f3 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -438,3 +438,30 @@  struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
 	rcu_read_unlock();
 	return buf;
 }
+
+/**
+ * tipc_node_get_linkname - get the name of a link
+ *
+ * @bearer_id: id of the bearer
+ * @node: peer node address
+ * @linkname: link name output buffer
+ *
+ * Returns 0 on success
+ */
+int tipc_node_get_linkname(u32 bearer_id, u32 addr, char *linkname, size_t len)
+{
+	struct tipc_link *link;
+	struct tipc_node *node = tipc_node_find(addr);
+
+	if ((bearer_id > MAX_BEARERS) || !node)
+		return -EINVAL;
+	tipc_node_lock(node);
+	link = node->links[bearer_id];
+	if (link) {
+		strncpy(linkname, link->name, len);
+		tipc_node_unlock(node);
+		return 0;
+	}
+	tipc_node_unlock(node);
+	return -EINVAL;
+}
diff --git a/net/tipc/node.h b/net/tipc/node.h
index 7cbb8ce..411b191 100644
--- a/net/tipc/node.h
+++ b/net/tipc/node.h
@@ -118,6 +118,7 @@  int tipc_node_active_links(struct tipc_node *n_ptr);
 int tipc_node_is_up(struct tipc_node *n_ptr);
 struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space);
 struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space);
+int tipc_node_get_linkname(u32 bearer_id, u32 node, char *linkname, size_t len);
 
 static inline void tipc_node_lock(struct tipc_node *n_ptr)
 {
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 3c02569..3f9912f 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -36,6 +36,7 @@ 
 
 #include "core.h"
 #include "port.h"
+#include "node.h"
 
 #include <linux/export.h>
 
@@ -1905,6 +1906,28 @@  static int tipc_getsockopt(struct socket *sock, int lvl, int opt,
 	return put_user(sizeof(value), ol);
 }
 
+int tipc_ioctl(struct socket *sk, unsigned int cmd, unsigned long arg)
+{
+	struct tipc_sioc_ln_req lnr;
+	void __user *argp = (void __user *)arg;
+
+	switch (cmd) {
+	case SIOCGETLINKNAME:
+		if (copy_from_user(&lnr, argp, sizeof(lnr)))
+			return -EFAULT;
+		if (!tipc_node_get_linkname(lnr.bearer_id, lnr.peer,
+					    lnr.linkname, TIPC_MAX_LINK_NAME)) {
+			if (copy_to_user(argp, &lnr, sizeof(lnr)))
+				return -EFAULT;
+			return 0;
+		}
+		return -EADDRNOTAVAIL;
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
 /* Protocol switches for the various types of TIPC sockets */
 
 static const struct proto_ops msg_ops = {
@@ -1917,7 +1940,7 @@  static const struct proto_ops msg_ops = {
 	.accept		= sock_no_accept,
 	.getname	= tipc_getname,
 	.poll		= tipc_poll,
-	.ioctl		= sock_no_ioctl,
+	.ioctl		= tipc_ioctl,
 	.listen		= sock_no_listen,
 	.shutdown	= tipc_shutdown,
 	.setsockopt	= tipc_setsockopt,
@@ -1938,7 +1961,7 @@  static const struct proto_ops packet_ops = {
 	.accept		= tipc_accept,
 	.getname	= tipc_getname,
 	.poll		= tipc_poll,
-	.ioctl		= sock_no_ioctl,
+	.ioctl		= tipc_ioctl,
 	.listen		= tipc_listen,
 	.shutdown	= tipc_shutdown,
 	.setsockopt	= tipc_setsockopt,
@@ -1959,7 +1982,7 @@  static const struct proto_ops stream_ops = {
 	.accept		= tipc_accept,
 	.getname	= tipc_getname,
 	.poll		= tipc_poll,
-	.ioctl		= sock_no_ioctl,
+	.ioctl		= tipc_ioctl,
 	.listen		= tipc_listen,
 	.shutdown	= tipc_shutdown,
 	.setsockopt	= tipc_setsockopt,