tipc: obtain node identity from interface by default

Selecting and explicitly configuring a TIPC node identity may be
unwanted in some cases.

In this commit we introduce a default setting if the identity has not
been set at the moment the first bearer is enabled. We do this by
using a raw copy of a unique identifier from the used interface: MAC
address in the case of an L2 bearer, IPv4/IPv6 address in the case
of a UDP bearer.
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>

net/tipc/bearer.c

@@ -243,12 +243,6 @@ static int tipc_enable_bearer(struct net *net, const char *name,
 	int res = -EINVAL;
 	char *errstr = "";
 
-	if (!tipc_own_id(net)) {
-		errstr = "not supported in standalone mode";
-		res = -ENOPROTOOPT;
-		goto rejected;
-	}
-
 	if (!bearer_name_validate(name, &b_names)) {
 		errstr = "illegal name";
 		goto rejected;
@@ -381,11 +375,13 @@ static void bearer_disable(struct net *net, struct tipc_bearer *b)
 int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b,
 			 struct nlattr *attr[])
 {
+	char *dev_name = strchr((const char *)b->name, ':') + 1;
+	int hwaddr_len = b->media->hwaddr_len;
+	u8 node_id[NODE_ID_LEN] = {0,};
 	struct net_device *dev;
-	char *driver_name = strchr((const char *)b->name, ':') + 1;
 
 	/* Find device with specified name */
-	dev = dev_get_by_name(net, driver_name);
+	dev = dev_get_by_name(net, dev_name);
 	if (!dev)
 		return -ENODEV;
 	if (tipc_mtu_bad(dev, 0)) {
@@ -393,6 +389,16 @@ int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b,
 		return -EINVAL;
 	}
 
+	/* Autoconfigure own node identity if needed */
+	if (!tipc_own_id(net) && hwaddr_len <= NODE_ID_LEN) {
+		memcpy(node_id, dev->dev_addr, hwaddr_len);
+		tipc_net_init(net, node_id, 0);
+	}
+	if (!tipc_own_id(net)) {
+		pr_warn("Failed to obtain node identity\n");
+		return -EINVAL;
+	}
+
 	/* Associate TIPC bearer with L2 bearer */
 	rcu_assign_pointer(b->media_ptr, dev);
 	b->pt.dev = dev;
@@ -400,7 +406,7 @@ int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b,
 	b->pt.func = tipc_l2_rcv_msg;
 	dev_add_pack(&b->pt);
 	memset(&b->bcast_addr, 0, sizeof(b->bcast_addr));
-	memcpy(b->bcast_addr.value, dev->broadcast, b->media->hwaddr_len);
+	memcpy(b->bcast_addr.value, dev->broadcast, hwaddr_len);
 	b->bcast_addr.media_id = b->media->type_id;
 	b->bcast_addr.broadcast = TIPC_BROADCAST_SUPPORT;
 	b->mtu = dev->mtu;

net/tipc/net.h

@@ -41,6 +41,7 @@
 
 extern const struct nla_policy tipc_nl_net_policy[];
 
+int tipc_net_init(struct net *net, u8 *node_id, u32 addr);
 void tipc_net_finalize(struct net *net, u32 addr);
 void tipc_net_stop(struct net *net);
 int tipc_nl_net_dump(struct sk_buff *skb, struct netlink_callback *cb);

net/tipc/udp_media.c

@@ -47,6 +47,8 @@
 #include <net/addrconf.h>
 #include <linux/tipc_netlink.h>
 #include "core.h"
+#include "addr.h"
+#include "net.h"
 #include "bearer.h"
 #include "netlink.h"
 #include "msg.h"
@@ -647,6 +649,7 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
 	struct udp_port_cfg udp_conf = {0};
 	struct udp_tunnel_sock_cfg tuncfg = {NULL};
 	struct nlattr *opts[TIPC_NLA_UDP_MAX + 1];
+	u8 node_id[NODE_ID_LEN] = {0,};
 
 	ub = kzalloc(sizeof(*ub), GFP_ATOMIC);
 	if (!ub)
@@ -677,6 +680,16 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
 	if (err)
 		goto err;
 
+	/* Autoconfigure own node identity if needed */
+	if (!tipc_own_id(net)) {
+		memcpy(node_id, local.ipv6.in6_u.u6_addr8, 16);
+		tipc_net_init(net, node_id, 0);
+	}
+	if (!tipc_own_id(net)) {
+		pr_warn("Failed to set node id, please configure manually\n");
+		return -EINVAL;
+	}
+
 	b->bcast_addr.media_id = TIPC_MEDIA_TYPE_UDP;
 	b->bcast_addr.broadcast = TIPC_BROADCAST_SUPPORT;
 	rcu_assign_pointer(b->media_ptr, ub);