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

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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.
This commit is contained in:
Guus Sliepen 2010-06-04 14:53:52 +02:00
parent dbf3d168b7
commit 4a21aabada
3 changed files with 19 additions and 0 deletions
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15
src/net.c
View file

@ -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) {

2
src/net.h
View file

@ -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"

2
src/protocol_edge.c
View file

@ -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;
}