Don't over write new receive-maximum if a v5 client connects.

This is for when it takes over an old session.

Closes #2134. Thanks to Frantisek Fuka.

ChangeLog.txt

@@ -1,6 +1,10 @@
 2.0.10 - 2021-xx-xx
 ==================
 
+Broker:
+- Don't over write new receive-maximum if a v5 client connects and takes over
+ an old session. Closes #2134.
+
 Clients:
 - Set `receive-maximum` to not exceed the `-C` message count in mosquitto_sub
  and mosquitto_rr, to avoid potentially lost messages. Closes #2134.

src/handle_connect.c

@@ -111,6 +111,8 @@ int connect__on_authorised(struct mosquitto *context, void *auth_data_out, uint1
  uint8_t connect_ack = 0;
  int i;
  int rc;
+ int in_quota, out_quota;
+ uint16_t in_maximum, out_maximum;
 
  /* Find if this client already has an entry. This must be done *after* any security checks. */
  HASH_FIND(hh_id, db.contexts_by_id, context->id, strlen(context->id), found_context);
@@ -135,12 +137,22 @@ int connect__on_authorised(struct mosquitto *context, void *auth_data_out, uint1
  if(found_context->msgs_in.inflight || found_context->msgs_in.queued
  || found_context->msgs_out.inflight || found_context->msgs_out.queued){
 
+ in_quota = context->msgs_in.inflight_quota;
+ out_quota = context->msgs_out.inflight_quota;
+ in_maximum = context->msgs_in.inflight_maximum;
+ out_maximum = context->msgs_out.inflight_maximum;
+
  memcpy(&context->msgs_in, &found_context->msgs_in, sizeof(struct mosquitto_msg_data));
  memcpy(&context->msgs_out, &found_context->msgs_out, sizeof(struct mosquitto_msg_data));
 
  memset(&found_context->msgs_in, 0, sizeof(struct mosquitto_msg_data));
  memset(&found_context->msgs_out, 0, sizeof(struct mosquitto_msg_data));
 
+ context->msgs_in.inflight_quota = in_quota;
+ context->msgs_out.inflight_quota = out_quota;
+ context->msgs_in.inflight_maximum = in_maximum;
+ context->msgs_out.inflight_maximum = out_maximum;
+
  db__message_reconnect_reset(context);
  }
  context->subs = found_context->subs;