stream/reassembly: improve progress tracking for GAP cases

When during raw reassembly it is detected that last ack is moved beyond
the progress and also beyond the data retrieved, update progress to the
last ack value.

Bug: #8272.

src/stream-tcp-reassemble.c

@@ -1878,6 +1878,12 @@ static int StreamReassembleRawDo(const TcpSession *ssn, const TcpStream *stream,
             progress = mydata_offset;
             SCLogDebug("raw progress now %"PRIu64, progress);
 
+            /* data is beyond the progress we'd like, and also beyond the last ack:
+             * there is a gap and we can't expect it to get filled anymore. */
+        } else if (mydata_offset > progress && mydata_offset == re) {
+            SCLogDebug("mydata_offset %" PRIu64 ", progress %" PRIu64 ", re %" PRIu64,
+                    mydata_offset, progress, re);
+            progress = re;
         } else {
             SCLogDebug("not increasing progress, data gap => mydata_offset "
                        "%"PRIu64" != progress %"PRIu64, mydata_offset, progress);