Detect and prevent two nodes with the same Name being on the VPN simultaneously.

In this situation, the two nodes will start fighting over the edges they announced.
When we have to contradict both ADD_EDGE and DEL_EDGE messages, we log a warning,
and with 25% chance per PingTimeout we quit.

diff --git a/src/net.c b/src/net.c
index 64bca947ff08b80c25b4735e68b06321c4e5ae39..ee58ac0a0b943bf1f2e1c8e0f9bba3f179189925 100644 (file)
--- a/src/net.c
+++ b/src/net.c
@@ -44,6 +44,8 @@ bool do_purge = false;
 volatile bool running = false;
 
 time_t now = 0;
+int contradicting_add_edge = 0;
+int contradicting_del_edge = 0;
 
 /* Purge edges and subnets of unreachable nodes. Use carefully. */
 
@@ -415,6 +417,19 @@ int main_loop(void) {
                                send_key_changed(broadcast, myself);
                                keyexpires = now + keylifetime;
                        }
+
+                       if(contradicting_del_edge && contradicting_add_edge) {
+                               logger(LOG_WARNING, "Possible node with same Name as us!");
+
+                               if(rand() % 3 == 0) {
+                                       logger(LOG_ERR, "Shutting down, check configuration of all nodes for duplicate Names!");
+                                       running = false;
+                                       break;
+                               }
+
+                               contradicting_add_edge = 0;
+                               contradicting_del_edge = 0;
+                       }
                }
 
                if(sigalrm) {

diff --git a/src/net.h b/src/net.h
index a97759fc80dfcf755e4b74bf24c327a63cec5c90..eae979cd1b72c59bf2d1a5b74a9792fb480842cd 100644 (file)
--- a/src/net.h
+++ b/src/net.h
@@ -115,6 +115,8 @@ extern bool do_prune;
 extern bool do_purge;
 extern char *myport;
 extern time_t now;
+extern int contradicting_add_edge;
+extern int contradicting_del_edge;
 
 /* Yes, very strange placement indeed, but otherwise the typedefs get all tangled up */
 #include "connection.h"

diff --git a/src/protocol_edge.c b/src/protocol_edge.c
index 300333b6b42b9567bbc21f4d21c903267982616d..32102d27af27a04cb6381a7129a97a45fef057df 100644 (file)
--- a/src/protocol_edge.c
+++ b/src/protocol_edge.c
@@ -133,6 +133,7 @@ bool add_edge_h(connection_t *c) {
        } else if(from == myself) {
                ifdebug(PROTOCOL) logger(LOG_WARNING, "Got %s from %s (%s) for ourself which does not exist",
                                   "ADD_EDGE", c->name, c->hostname);
+               contradicting_add_edge++;
                e = new_edge();
                e->from = from;
                e->to = to;
@@ -229,6 +230,7 @@ bool del_edge_h(connection_t *c) {
        if(e->from == myself) {
                ifdebug(PROTOCOL) logger(LOG_WARNING, "Got %s from %s (%s) for ourself",
                                   "DEL_EDGE", c->name, c->hostname);
+               contradicting_del_edge++;
                send_add_edge(c, e);    /* Send back a correction */
                return true;
        }