tipc: introduce ioctl for fetching node identity

After the introduction of a 128-bit node identity it may be difficult
for a user to correlate between this identity and the generated node
hash address.

We now try to make this easier by introducing a new ioctl() call for
fetching a node identity by using the hash value as key. This will
be particularly useful when we extend some of the commands in the
'tipc' tool, but we also expect regular user applications to need
this feature.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/tipc.h

@@ -209,16 +209,16 @@ struct tipc_group_req {
  * The string formatting for each name element is:
  * media: media
  * interface: media:interface name
- * link: Z.C.N:interface-Z.C.N:interface
- *
+ * link: node:interface-node:interface
  */
-
+#define TIPC_NODEID_LEN         16
 #define TIPC_MAX_MEDIA_NAME	16
 #define TIPC_MAX_IF_NAME	16
 #define TIPC_MAX_BEARER_NAME	32
 #define TIPC_MAX_LINK_NAME	68
 
-#define SIOCGETLINKNAME		SIOCPROTOPRIVATE
+#define SIOCGETLINKNAME        SIOCPROTOPRIVATE
+#define SIOCGETNODEID          (SIOCPROTOPRIVATE + 1)
 
 struct tipc_sioc_ln_req {
 	__u32 peer;
@@ -226,6 +226,10 @@ struct tipc_sioc_ln_req {
 	char linkname[TIPC_MAX_LINK_NAME];
 };
 
+struct tipc_sioc_nodeid_req {
+	__u32 peer;
+	char node_id[TIPC_NODEID_LEN];
+};
 
 /* The macros and functions below are deprecated:
  */

net/tipc/node.c

@@ -195,6 +195,27 @@ int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel)
 	return mtu;
 }
 
+bool tipc_node_get_id(struct net *net, u32 addr, u8 *id)
+{
+	u8 *own_id = tipc_own_id(net);
+	struct tipc_node *n;
+
+	if (!own_id)
+		return true;
+
+	if (addr == tipc_own_addr(net)) {
+		memcpy(id, own_id, TIPC_NODEID_LEN);
+		return true;
+	}
+	n = tipc_node_find(net, addr);
+	if (!n)
+		return false;
+
+	memcpy(id, &n->peer_id, TIPC_NODEID_LEN);
+	tipc_node_put(n);
+	return true;
+}
+
 u16 tipc_node_get_capabilities(struct net *net, u32 addr)
 {
 	struct tipc_node *n;

net/tipc/node.h

@@ -60,6 +60,7 @@ enum {
 #define INVALID_BEARER_ID -1
 
 void tipc_node_stop(struct net *net);
+bool tipc_node_get_id(struct net *net, u32 addr, u8 *id);
 u32 tipc_node_try_addr(struct net *net, u8 *id, u32 addr);
 void tipc_node_check_dest(struct net *net, u32 onode, u8 *peer_id128,
 			  struct tipc_bearer *bearer,

net/tipc/socket.c

@@ -2973,7 +2973,8 @@ static int tipc_getsockopt(struct socket *sock, int lvl, int opt,
 
 static int tipc_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 {
-	struct sock *sk = sock->sk;
+	struct net *net = sock_net(sock->sk);
+	struct tipc_sioc_nodeid_req nr = {0};
 	struct tipc_sioc_ln_req lnr;
 	void __user *argp = (void __user *)arg;
 
@@ -2981,7 +2982,7 @@ static int tipc_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 	case SIOCGETLINKNAME:
 		if (copy_from_user(&lnr, argp, sizeof(lnr)))
 			return -EFAULT;
-		if (!tipc_node_get_linkname(sock_net(sk),
+		if (!tipc_node_get_linkname(net,
 					    lnr.bearer_id & 0xffff, lnr.peer,
 					    lnr.linkname, TIPC_MAX_LINK_NAME)) {
 			if (copy_to_user(argp, &lnr, sizeof(lnr)))
@@ -2989,6 +2990,14 @@ static int tipc_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 			return 0;
 		}
 		return -EADDRNOTAVAIL;
+	case SIOCGETNODEID:
+		if (copy_from_user(&nr, argp, sizeof(nr)))
+			return -EFAULT;
+		if (!tipc_node_get_id(net, nr.peer, nr.node_id))
+			return -EADDRNOTAVAIL;
+		if (copy_to_user(argp, &nr, sizeof(nr)))
+			return -EFAULT;
+		return 0;
 	default:
 		return -ENOIOCTLCMD;
 	}