7 files changed, 88 insertions, 1 deletions

diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 1336f3cdad38..34f3e5641438 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -406,8 +406,10 @@ int tipc_mcast_xmit(struct net *net, struct sk_buff_head *pkts,
                         rc = tipc_bcast_xmit(net, pkts, cong_link_cnt);
         }
 
-        if (dests->local)
+        if (dests->local) {
+                tipc_loopback_trace(net, &localq);
                 tipc_sk_mcast_rcv(net, &localq, &inputq);
+        }
 exit:
         /* This queue should normally be empty by now */
         __skb_queue_purge(pkts);
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index a809c0ec8d15..0214aa1c4427 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -389,6 +389,11 @@ int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b,
                 dev_put(dev);
                 return -EINVAL;
         }
+        if (dev == net->loopback_dev) {
+                dev_put(dev);
+                pr_info("Enabling <%s> not permitted\n", b->name);
+                return -EINVAL;
+        }
 
         /* Autoconfigure own node identity if needed */
         if (!tipc_own_id(net) && hwaddr_len <= NODE_ID_LEN) {
@@ -674,6 +679,65 @@ void tipc_bearer_stop(struct net *net)
         }
 }
 
+void tipc_clone_to_loopback(struct net *net, struct sk_buff_head *pkts)
+{
+        struct net_device *dev = net->loopback_dev;
+        struct sk_buff *skb, *_skb;
+        int exp;
+
+        skb_queue_walk(pkts, _skb) {
+                skb = pskb_copy(_skb, GFP_ATOMIC);
+                if (!skb)
+                        continue;
+
+                exp = SKB_DATA_ALIGN(dev->hard_header_len - skb_headroom(skb));
+                if (exp > 0 && pskb_expand_head(skb, exp, 0, GFP_ATOMIC)) {
+                        kfree_skb(skb);
+                        continue;
+                }
+
+                skb_reset_network_header(skb);
+                dev_hard_header(skb, dev, ETH_P_TIPC, dev->dev_addr,
+                                dev->dev_addr, skb->len);
+                skb->dev = dev;
+                skb->pkt_type = PACKET_HOST;
+                skb->ip_summed = CHECKSUM_UNNECESSARY;
+                skb->protocol = eth_type_trans(skb, dev);
+                netif_rx_ni(skb);
+        }
+}
+
+static int tipc_loopback_rcv_pkt(struct sk_buff *skb, struct net_device *dev,
+                                 struct packet_type *pt, struct net_device *od)
+{
+        consume_skb(skb);
+        return NET_RX_SUCCESS;
+}
+
+int tipc_attach_loopback(struct net *net)
+{
+        struct net_device *dev = net->loopback_dev;
+        struct tipc_net *tn = tipc_net(net);
+
+        if (!dev)
+                return -ENODEV;
+
+        dev_hold(dev);
+        tn->loopback_pt.dev = dev;
+        tn->loopback_pt.type = htons(ETH_P_TIPC);
+        tn->loopback_pt.func = tipc_loopback_rcv_pkt;
+        dev_add_pack(&tn->loopback_pt);
+        return 0;
+}
+
+void tipc_detach_loopback(struct net *net)
+{
+        struct tipc_net *tn = tipc_net(net);
+
+        dev_remove_pack(&tn->loopback_pt);
+        dev_put(net->loopback_dev);
+}
+
 /* Caller should hold rtnl_lock to protect the bearer */
 static int __tipc_nl_add_bearer(struct tipc_nl_msg *msg,
                                 struct tipc_bearer *bearer, int nlflags)
diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index 7f4c569594a5..ea0f3c49cbed 100644
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -232,6 +232,16 @@ void tipc_bearer_xmit(struct net *net, u32 bearer_id,
                       struct tipc_media_addr *dst);
 void tipc_bearer_bc_xmit(struct net *net, u32 bearer_id,
                          struct sk_buff_head *xmitq);
+void tipc_clone_to_loopback(struct net *net, struct sk_buff_head *pkts);
+int tipc_attach_loopback(struct net *net);
+void tipc_detach_loopback(struct net *net);
+
+static inline void tipc_loopback_trace(struct net *net,
+                                       struct sk_buff_head *pkts)
+{
+        if (unlikely(dev_nit_active(net->loopback_dev)))
+                tipc_clone_to_loopback(net, pkts);
+}
 
 /* check if device MTU is too low for tipc headers */
 static inline bool tipc_mtu_bad(struct net_device *dev, unsigned int reserve)
diff --git a/net/tipc/core.c b/net/tipc/core.c
index c8370722f0bb..23cb379a93d6 100644
--- a/net/tipc/core.c
+++ b/net/tipc/core.c
@@ -82,6 +82,10 @@ static int __net_init tipc_init_net(struct net *net)
         if (err)
                 goto out_bclink;
 
+        err = tipc_attach_loopback(net);
+        if (err)
+                goto out_bclink;
+
         return 0;
 
 out_bclink:
@@ -94,6 +98,7 @@ out_sk_rht:
 
 static void __net_exit tipc_exit_net(struct net *net)
 {
+        tipc_detach_loopback(net);
         tipc_net_stop(net);
         tipc_bcast_stop(net);
         tipc_nametbl_stop(net);
diff --git a/net/tipc/core.h b/net/tipc/core.h
index 7a68e1b6a066..60d829581068 100644
--- a/net/tipc/core.h
+++ b/net/tipc/core.h
@@ -125,6 +125,9 @@ struct tipc_net {
 
         /* Cluster capabilities */
         u16 capabilities;
+
+        /* Tracing of node internal messages */
+        struct packet_type loopback_pt;
 };
 
 static inline struct tipc_net *tipc_net(struct net *net)
diff --git a/net/tipc/node.c b/net/tipc/node.c
index 7ca019001f7c..1bdcf0fc1a4d 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -1443,6 +1443,7 @@ int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
         int rc;
 
         if (in_own_node(net, dnode)) {
+                tipc_loopback_trace(net, list);
                 tipc_sk_rcv(net, list);
                 return 0;
         }
diff --git a/net/tipc/topsrv.c b/net/tipc/topsrv.c
index ca8ac96d22a9..3a12fc18239b 100644
--- a/net/tipc/topsrv.c
+++ b/net/tipc/topsrv.c
@@ -40,6 +40,7 @@
 #include "socket.h"
 #include "addr.h"
 #include "msg.h"
+#include "bearer.h"
 #include <net/sock.h>
 #include <linux/module.h>
 
@@ -608,6 +609,7 @@ static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
         memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
         skb_queue_head_init(&evtq);
         __skb_queue_tail(&evtq, skb);
+        tipc_loopback_trace(net, &evtq);
         tipc_sk_rcv(net, &evtq);
 }