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SubjectRe: want opinions on possible glitch in 2.4 network error reporting
On Thu, 7 Feb 2002, Alan Cox wrote:

> > there is no way to "lose" that data before it hits the wire, unless of
> > course the network driver is broken and doesn't plug the upper layers when
> > its TX queue is full.
>
> UDP is not flow controlled.

No, of course not, but this has *nothing* to do with UDP. The IP socket
itself is flow controlled, and so is the TX queue of the network driver.

Let me give you another example: ping -f. If what you said were true, ping -f
would send packets as fast as the CPU can generate into the black hole
called an IP raw socket, right? Well, that just doesn't happen, because
sendto/sendmsg will block until there is enough space in the TX queue of
the raw socket.

I'll state again: if data (UDP or otherwise) is lost after sendto()
returns success but before it hits the wire, something is BROKEN in that
IP stack.

Ion

--
It is better to keep your mouth shut and be thought a fool,
than to open it and remove all doubt.

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