polypath asymmetric routing: Handle MSG1 late dupes

[secnet] / site.c

diff --git a/site.c b/site.c
index bc902ad..2bab3f7 100644 (file)
--- a/site.c
+++ b/site.c
@@ -1093,8 +1093,8 @@ decrypt_msg0(struct site *st, struct buffer_if *msg0,
                           "peer has used new key","auxiliary key",LOG_SEC);
        return 0;
     }
-    if (problem==transform_apply_seqrange)
-       goto skew;
+    if (transform_apply_return_badseq(problem))
+       goto badseq;
 
     buffer_copy(msg0, &st->scratch);
     problem = call_transform_reverse(st,st->auxiliary_key.transform,
@@ -1118,8 +1118,8 @@ decrypt_msg0(struct site *st, struct buffer_if *msg0,
        }
        return 0;
     }
-    if (problem==transform_apply_seqrange)
-       goto skew;
+    if (transform_apply_return_badseq(problem))
+       goto badseq;
 
     if (st->state==SITE_SENTMSG5) {
        buffer_copy(msg0, &st->scratch);
@@ -1134,8 +1134,8 @@ decrypt_msg0(struct site *st, struct buffer_if *msg0,
            activate_new_key(st);
            return 0; /* do process the data in this packet */
        }
-       if (problem==transform_apply_seqrange)
-           goto skew;
+       if (transform_apply_return_badseq(problem))
+           goto badseq;
     }
 
     slog(st,LOG_SEC,"transform: %s (aux: %s, new: %s)",
@@ -1145,8 +1145,8 @@ decrypt_msg0(struct site *st, struct buffer_if *msg0,
     assert(problem);
     return problem;
 
- skew:
-    slog(st,LOG_DROP,"transform: %s (merely skew)",transform_err);
+ badseq:
+    slog(st,LOG_DROP,"transform: %s (bad seq.)",transform_err);
     assert(problem);
     return problem;
 }
@@ -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;