pipe mode and sendfile?

Poul-Henning Kamp phk at phk.freebsd.dk
Tue Mar 29 16:26:28 CEST 2016

In message <CABoVN9DfHVJ7VUznjSzRxCg4inzgOoqg6GdXGhiZqfo=D7SnZw at mail.gmail.com>
, Dridi Boukelmoune writes:

>> It's bad enough to pipe half the HTTP streams to one backend and
>> the other half to the other.  Think for instance about how we would
>> merge the two backend->client HPACK state into one.
>You're not supposed to do that, HPACK is maintained as a one-way
>compression between two parties and cannot be shared with

That just means that we would have to decompress and recompress
all the streams, in which case we might as well return(pass).

>We need CONNECT piping to comply with the RFC, and as I said in
>previous comments, I believe that's the only kind of "true" pipe we
>can do in H2, and it's stream-based.

No, we can also do transparent piping, for instance based on ACL
matches and similar.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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