Cluster PUBLISH message: fix totlen count.

bulk_data field size was not removed from the count. It is not possible
to declare it simply as 'char bulk_data[]' since the structure is nested
into another structure.

src/cluster.c

@@ -1482,7 +1482,8 @@ int clusterProcessPacket(clusterLink *link) {
     } else if (type == CLUSTERMSG_TYPE_PUBLISH) {
         uint32_t explen = sizeof(clusterMsg)-sizeof(union clusterMsgData);
 
-        explen += sizeof(clusterMsgDataPublish) +
+        explen += sizeof(clusterMsgDataPublish) -
+                8 +
                 ntohl(hdr->data.publish.msg.channel_len) +
                 ntohl(hdr->data.publish.msg.message_len);
         if (totlen != explen) return 1;
@@ -2184,7 +2185,7 @@ void clusterSendPublish(clusterLink *link, robj *channel, robj *message) {
 
     clusterBuildMessageHdr(hdr,CLUSTERMSG_TYPE_PUBLISH);
     totlen = sizeof(clusterMsg)-sizeof(union clusterMsgData);
-    totlen += sizeof(clusterMsgDataPublish) + channel_len + message_len;
+    totlen += sizeof(clusterMsgDataPublish) - 8 + channel_len + message_len;
 
     hdr->data.publish.msg.channel_len = htonl(channel_len);
     hdr->data.publish.msg.message_len = htonl(message_len);

src/cluster.h

@@ -176,7 +176,10 @@ typedef struct {
 typedef struct {
     uint32_t channel_len;
     uint32_t message_len;
-    unsigned char bulk_data[8]; /* defined as 8 just for alignment concerns. */
+    /* We can't reclare bulk_data as bulk_data[] since this structure is
+     * nested. The 8 bytes are removed from the count during the message
+     * length computation. */
+    unsigned char bulk_data[8];
 } clusterMsgDataPublish;
 
 typedef struct {