Re: TCP torture testing

[Brandon Martin <lists.nanog () monmotha net>]

On 1/17/25 14:29, William Herrin wrote:
> Well... In theory, TCP closes the segment at the end of the
> application's send() and sets the PSH flag. Likewise, on the receiving
> side the recv() returns before filling the buffer upon receipt of a
> segment with the PSH flag set.

Every segment this thing sends has PSH set which again makes me think 
that they've got TCP_NODELAY set but are sending their messages 
piecemeal across multiple send/write calls.

The actual high-level messages are fairly small at typically less than 
100B.  Most implementations end up sending the entire message in a 
single TCP segment.

> In theory. In practice, it doesn't always work out that way and
> applications which depend on a short recv() meaning that was where the
> sender's send() ended tend to flake out in unexpected ways.

I don't think that's the issue in this case, but it's a useful thing to 
go looking for.

--
Brandon Martin