Fix the TLS and REPS issues about CLUSTER SLOTS cache (#581)

PR #53 introduced the cache of CLUSTER SLOTS response, but the cache has
some problems for different types of clients:

1. the RESP version is wrongly ignored:

    ```
    $./valkey-cli
    127.0.0.1:6379> cluster slots
    1) 1) (integer) 0
       2) (integer) 16383
       3) 1) ""
          2) (integer) 6379
          3) "f1aeceb352401ce57acd432c68c60b359c00ef85"
          4) (empty array)
    127.0.0.1:6379> hello 3
    1# "server" => "valkey"
    2# "version" => "255.255.255"
    3# "proto" => (integer) 3
    4# "id" => (integer) 3
    5# "mode" => "cluster"
    6# "role" => "master"
    7# "modules" => (empty array)
    127.0.0.1:6379> cluster slots
    1) 1) (integer) 0
       2) (integer) 16383
       3) 1) ""
          2) (integer) 6379
          3) "f1aeceb352401ce57acd432c68c60b359c00ef85"
          4) (empty array)
    ```

    RESP3 should get "empty hash" but get RESP2's "empty array"

3. we should use the original client's connect type, or lua/function and
module would get wrong port:

    ```
    $./valkey-cli --tls --insecure -p 6789
    127.0.0.1:6789> config get port tls-port
    1) "tls-port"
    2) "6789"
    3) "port"
    4) "6379"
    127.0.0.1:6789> cluster slots
    1) 1) (integer) 0
       2) (integer) 16383
       3) 1) ""
          2) (integer) 6789
          3) "f1aeceb352401ce57acd432c68c60b359c00ef85"
          4) (empty array)
    127.0.0.1:6789> eval "return redis.call('cluster','slots')" 0
    1) 1) (integer) 0
       2) (integer) 16383
       3) 1) ""
          2) (integer) 6379
          3) "f1aeceb352401ce57acd432c68c60b359c00ef85"
          4) (empty array)
        ```

---------

Signed-off-by: zhaozhao.zz <zhaozhao.zz@alibaba-inc.com>

src/cluster.c

@@ -1354,15 +1354,17 @@ void addNodeReplyForClusterSlot(client *c, clusterNode *node, int start_slot, in
 
 void clearCachedClusterSlotsResponse(void) {
     for (connTypeForCaching conn_type = CACHE_CONN_TCP; conn_type < CACHE_CONN_TYPE_MAX; conn_type++) {
-        if (server.cached_cluster_slot_info[conn_type]) {
-            sdsfree(server.cached_cluster_slot_info[conn_type]);
-            server.cached_cluster_slot_info[conn_type] = NULL;
+        for (int resp = 0; resp <= 3; resp++) {
+            if (server.cached_cluster_slot_info[conn_type][resp]) {
+                sdsfree(server.cached_cluster_slot_info[conn_type][resp]);
+                server.cached_cluster_slot_info[conn_type][resp] = NULL;
+            }
         }
     }
 }
 
-sds generateClusterSlotResponse(void) {
-    client *recording_client = createCachedResponseClient();
+sds generateClusterSlotResponse(int resp) {
+    client *recording_client = createCachedResponseClient(resp);
     clusterNode *n = NULL;
     int num_primaries = 0, start = -1;
     void *slot_replylen = addReplyDeferredLen(recording_client);
@@ -1392,8 +1394,8 @@ sds generateClusterSlotResponse(void) {
     return cluster_slot_response;
 }
 
-int verifyCachedClusterSlotsResponse(sds cached_response) {
-    sds generated_response = generateClusterSlotResponse();
+int verifyCachedClusterSlotsResponse(sds cached_response, int resp) {
+    sds generated_response = generateClusterSlotResponse(resp);
     int is_equal = !sdscmp(generated_response, cached_response);
     /* Here, we use LL_WARNING so this gets printed when debug assertions are enabled and the system is about to crash. */
     if (!is_equal)
@@ -1413,16 +1415,16 @@ void clusterCommandSlots(client *c) {
      *               3) node ID
      *           ... continued until done
      */
-    connTypeForCaching conn_type = connIsTLS(c->conn);
+    connTypeForCaching conn_type = shouldReturnTlsInfo();
 
     if (detectAndUpdateCachedNodeHealth()) clearCachedClusterSlotsResponse();
 
-    sds cached_reply = server.cached_cluster_slot_info[conn_type];
+    sds cached_reply = server.cached_cluster_slot_info[conn_type][c->resp];
     if (!cached_reply) {
-        cached_reply = generateClusterSlotResponse();
-        server.cached_cluster_slot_info[conn_type] = cached_reply;
+        cached_reply = generateClusterSlotResponse(c->resp);
+        server.cached_cluster_slot_info[conn_type][c->resp] = cached_reply;
     } else {
-        debugServerAssertWithInfo(c, NULL, verifyCachedClusterSlotsResponse(cached_reply) == 1);
+        debugServerAssertWithInfo(c, NULL, verifyCachedClusterSlotsResponse(cached_reply, c->resp) == 1);
     }
 
     addReplyProto(c, cached_reply, sdslen(cached_reply));

src/cluster.h

@@ -104,7 +104,7 @@ const char *clusterNodePreferredEndpoint(clusterNode *n);
 long long clusterNodeReplOffset(clusterNode *node);
 clusterNode *clusterLookupNode(const char *name, int length);
 int detectAndUpdateCachedNodeHealth(void);
-client *createCachedResponseClient(void);
+client *createCachedResponseClient(int resp);
 void deleteCachedResponseClient(client *recording_client);
 void clearCachedClusterSlotsResponse(void);
 unsigned int countKeysInSlot(unsigned int hashslot);

src/cluster_legacy.c

@@ -1033,7 +1033,9 @@ void clusterInit(void) {
     server.cluster->mf_end = 0;
     server.cluster->mf_replica = NULL;
     for (connTypeForCaching conn_type = CACHE_CONN_TCP; conn_type < CACHE_CONN_TYPE_MAX; conn_type++) {
-        server.cached_cluster_slot_info[conn_type] = NULL;
+        for (int resp = 0; resp <= 3; resp++) {
+            server.cached_cluster_slot_info[conn_type][resp] = NULL;
+        }
     }
     resetManualFailover();
     clusterUpdateMyselfFlags();

src/networking.c

@@ -339,8 +339,9 @@ sds aggregateClientOutputBuffer(client *c) {
  * to initiate caching of any command response.
  *
  * It needs be paired with `deleteCachedResponseClient` function to stop caching. */
-client *createCachedResponseClient(void) {
+client *createCachedResponseClient(int resp) {
     struct client *recording_client = createClient(NULL);
+    recording_client->resp = resp;
     /* Allocating the `conn` allows to prepare the caching client before adding
      * data to the clients output buffer by `prepareClientToWrite`. */
     recording_client->conn = zcalloc(sizeof(connection));

src/server.h

@@ -2075,7 +2075,7 @@ struct valkeyServer {
                                                             * dropping packets of a specific type */
     /* Debug config that goes along with cluster_drop_packet_filter. When set, the link is closed on packet drop. */
     uint32_t debug_cluster_close_link_on_packet_drop : 1;
-    sds cached_cluster_slot_info[CACHE_CONN_TYPE_MAX];
+    sds cached_cluster_slot_info[CACHE_CONN_TYPE_MAX][4]; /* Align to RESP3 */
     /* Scripting */
     mstime_t busy_reply_threshold;  /* Script / module timeout in milliseconds */
     int pre_command_oom_state;      /* OOM before command (script?) was started */
@@ -2738,7 +2738,7 @@ void initSharedQueryBuf(void);
 client *lookupClientByID(uint64_t id);
 int authRequired(client *c);
 void putClientInPendingWriteQueue(client *c);
-client *createCachedResponseClient(void);
+client *createCachedResponseClient(int resp);
 void deleteCachedResponseClient(client *recording_client);
 
 /* logreqres.c - logging of requests and responses */