[TIPC]: Added duplicate node address detection capability

TIPC now rejects and logs link setup requests from node <Z.C.N> if the
receiving node already has a functional link to that node on the associated
interface, or if the requestor is using the same <Z.C.N> as the receiver.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Per Liden <per.liden@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 1 deletions

diff --git a/net/tipc/discover.c b/net/tipc/discover.c
index ee94de92ae99..cc748d4d4742 100644
--- a/net/tipc/discover.c
+++ b/net/tipc/discover.c
@@ -132,6 +132,28 @@ static struct sk_buff *tipc_disc_init_msg(u32 type,
 }
 
 /**
+ * disc_dupl_alert - issue node address duplication alert
+ * @b_ptr: pointer to bearer detecting duplication
+ * @node_addr: duplicated node address
+ * @media_addr: media address advertised by duplicated node
+ */
+
+static void disc_dupl_alert(struct bearer *b_ptr, u32 node_addr,
+                            struct tipc_media_addr *media_addr)
+{
+        char node_addr_str[16];
+        char media_addr_str[64];
+        struct print_buf pb;
+
+        addr_string_fill(node_addr_str, node_addr);
+        tipc_printbuf_init(&pb, media_addr_str, sizeof(media_addr_str));
+        tipc_media_addr_printf(&pb, media_addr);
+        tipc_printbuf_validate(&pb);
+        warn("Duplicate %s using %s seen on <%s>\n",
+             node_addr_str, media_addr_str, b_ptr->publ.name);
+}
+
+/**
  * tipc_disc_recv_msg - handle incoming link setup message (request or response)
  * @buf: buffer containing message
  */
@@ -157,8 +179,11 @@ void tipc_disc_recv_msg(struct sk_buff *buf)
                 return;
         if (!tipc_addr_node_valid(orig))
                 return;
-        if (orig == tipc_own_addr)
+        if (orig == tipc_own_addr) {
+                if (memcmp(&media_addr, &b_ptr->publ.addr, sizeof(media_addr)))
+                        disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr);
                 return;
+        }
         if (!in_scope(dest, tipc_own_addr))
                 return;
         if (is_slave(tipc_own_addr) && is_slave(orig))
@@ -190,6 +215,11 @@ void tipc_disc_recv_msg(struct sk_buff *buf)
                 }
                 addr = &link->media_addr;
                 if (memcmp(addr, &media_addr, sizeof(*addr))) {
+                        if (tipc_link_is_up(link) || (!link->started)) {
+                                disc_dupl_alert(b_ptr, orig, &media_addr);
+                                spin_unlock_bh(&n_ptr->lock);
+                                return;
+                        }
                         warn("Resetting link <%s>, peer interface address changed\n",
                              link->name);
                         memcpy(addr, &media_addr, sizeof(*addr));