net: use correct dns msg size
Set bufSize to the actual dns message size, so that the p.Start (below) gets a fully valid dns message.
Change-Id: I585e8a3d71f88db93e09bd0dbbc0875ee6de9a97
GitHub-Last-Rev:
0967be35012d2e28366e6d47eee4968c7e8d5e4a
GitHub-Pull-Request: golang/go#57392
Reviewed-on: https://go-review.googlesource.com/c/go/+/458375
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>