Make sure the new and old pathfinders will never try to answer reques…

…ts for nodes older/newer than v20

dht/Pathfinder.c

@@ -135,6 +135,11 @@ static Iface_DEFUN sendNode(struct Message* msg,
                             uint32_t metric,
                             struct Pathfinder_pvt* pf)
 {
+    if (addr->protocolVersion > 19) {
+        Log_debug(pf->log, "not sending [%s] because version new",
+            Address_toString(addr, msg->alloc)->bytes);
+        return NULL;
+    }
     Message_reset(msg);
     Message_shift(msg, PFChan_Node_SIZE, NULL);
     nodeForAddress((struct PFChan_Node*) msg->bytes, addr, metric);
@@ -276,6 +281,9 @@ static Iface_DEFUN switchErr(struct Message* msg, struct Pathfinder_pvt* pf)
 
 static Iface_DEFUN searchReq(struct Message* msg, struct Pathfinder_pvt* pf)
 {
+    uint32_t version = Message_pop32(msg, NULL);
+    Message_pop32(msg, NULL);
+    if (version >= 20) { return NULL; }
     uint8_t addr[16];
     Message_pop(msg, addr, 16, NULL);
     Assert_true(!msg->length);

net/SessionManager.c

@@ -470,10 +470,12 @@ static void unsetupSession(struct SessionManager_pvt* sm, struct SessionManager_
     Allocator_free(eventAlloc);
 }
 
-static void triggerSearch(struct SessionManager_pvt* sm, uint8_t target[16])
+static void triggerSearch(struct SessionManager_pvt* sm, uint8_t target[16], uint32_t version)
 {
     struct Allocator* eventAlloc = Allocator_child(sm->alloc);
     struct Message* eventMsg = Message_new(0, 512, eventAlloc);
+    Message_push32(eventMsg, version, NULL);
+    Message_push32(eventMsg, 0, NULL);
     Message_push(eventMsg, target, 16, NULL);
     Message_push32(eventMsg, 0xffffffff, NULL);
     Message_push32(eventMsg, PFChan_Core_SEARCH_REQ, NULL);
@@ -500,9 +502,10 @@ static void checkTimedOutSessions(struct SessionManager_pvt* sm)
         if (now - sess->pub.lastSearchTime >= sm->pub.sessionSearchAfterMilliseconds) {
             // Session is not in idle state and requires a search
             // But we're only going to trigger one search per cycle.
-            if (searchTriggered) { continue; }
+            // Except for v20 because the snode will answer us.
+            if (searchTriggered && sess->pub.version < 20) { continue; }
             debugSession0(sm->log, sess, "triggering search");
-            triggerSearch(sm, sess->pub.caSession->herIp6);
+            triggerSearch(sm, sess->pub.caSession->herIp6, sess->pub.version);
             sess->pub.lastSearchTime = now;
             searchTriggered = true;
         } else if (CryptoAuth_getState(sess->pub.caSession) < CryptoAuth_State_RECEIVED_KEY) {
@@ -557,7 +560,7 @@ static void needsLookup(struct SessionManager_pvt* sm, struct Message* msg, bool
     Allocator_adopt(lookupAlloc, msg->alloc);
     Assert_true(Map_BufferedMessages_put((struct Ip6*)header->ip6, &buffered, &sm->bufMap) > -1);
 
-    triggerSearch(sm, header->ip6);
+    triggerSearch(sm, header->ip6, Endian_hostToBigEndian32(header->version_be));
 }
 
 static Iface_DEFUN readyToSend(struct Message* msg,

subnode/SubnodePathfinder.c

@@ -150,13 +150,23 @@ static void getRouteReply(Dict* msg, struct Address* src, struct MsgCore_Promise
     struct Address_List* al = ReplySerializer_parse(src, msg, pf->log, false, prom->alloc);
     if (!al || al->length == 0) { return; }
     Log_debug(pf->log, "reply with[%s]", Address_toString(&al->elems[0], prom->alloc)->bytes);
+
+    if (al->elems[0].protocolVersion < 20) {
+        Log_debug(pf->log, "not sending [%s] because version is old",
+            Address_toString(&al->elems[0], prom->alloc)->bytes);
+        return;
+    }
+
     //NodeCache_discoverNode(pf->nc, &al->elems[0]);
     struct Message* msgToCore = Message_new(0, 512, prom->alloc);
     Iface_CALL(sendNode, msgToCore, &al->elems[0], 0xfff00000, PFChan_Pathfinder_NODE, pf);
 }
 
 static Iface_DEFUN searchReq(struct Message* msg, struct SubnodePathfinder_pvt* pf)
 {
+    uint32_t version = Message_pop32(msg, NULL);
+    Message_pop32(msg, NULL);
+    if (version && version < 20) { return NULL; }
     uint8_t addr[16];
     Message_pop(msg, addr, 16, NULL);
     Assert_true(!msg->length);

wire/PFChan.h

@@ -302,8 +302,12 @@ enum PFChan_Core
 struct PFChan_Core_SearchReq
 {
     uint8_t ipv6[16];
+
+    uint32_t pad;
+
+    uint32_t version_be;
 };
-#define PFChan_Core_SearchReq_SIZE 16
+#define PFChan_Core_SearchReq_SIZE 24
 Assert_compileTime(sizeof(struct PFChan_Core_SearchReq) == PFChan_Core_SearchReq_SIZE);
 
 struct PFChan_Core_Pathfinder