polypath asymmetric routing: Handle MSG1 late dupes

[secnet.git] / site.c

diff --git a/site.c b/site.c
index acbc2b62c99b9ed43e48b43a3d473becfdd404c3..2bab3f769238af33fa4fd1d48e8baf07de361513 100644 (file)
--- a/site.c
+++ b/site.c
@@ -1158,6 +1158,14 @@ static bool_t process_msg0(struct site *st, struct buffer_if *msg0,
     transform_apply_return problem;
 
     problem = decrypt_msg0(st,msg0,src);
+    if (problem==transform_apply_seqdupe) {
+       /* We recently received another copy of this packet, maybe due
+        * to polypath.  That's not a problem; indeed, for the
+        * purposes of transport address management it is a success.
+        * But we don't want to process the packet. */
+       transport_data_msgok(st,src);
+       return False;
+    }
     if (problem)
        return False;
 
@@ -1831,9 +1839,21 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
                BUF_FREE(buf);
                return True;
            }
+       } else if (st->state==SITE_SENTMSG2 ||
+                  st->state==SITE_SENTMSG4) {
+           if (consttime_memeq(named_msg.nR,st->remoteN,NONCELEN)) {
+               /* We are ahead in the protocol, but that msg1 had the
+                * peer's nonce so presumably it is from this key
+                * exchange run, via a slower route */
+               transport_setup_msgok(st,source);
+           } else {
+               slog(st,LOG_UNEXPECTED,"competing incoming message 1");
+           }
+           BUF_FREE(buf);
+           return True;
        }
        /* The message 1 was received at an unexpected stage of the
-          key setup. XXX POLICY - what do we do? */
+          key setup.  Well, they lost the race. */
        slog(st,LOG_UNEXPECTED,"unexpected incoming message 1");
        BUF_FREE(buf);
        return True;