netdev - Re: eBPF - little-endian load instructions?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1492002120.2855.3.camel@sipsolutions.net>
Date:   Wed, 12 Apr 2017 15:02:00 +0200
From:   Johannes Berg <johannes@...solutions.net>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Alexei Starovoitov <ast@...nel.org>
Subject: Re: eBPF - little-endian load instructions?

On Tue, 2017-04-11 at 13:06 +0200, Daniel Borkmann wrote:
> 
> There are instructions to convert endianess, see __bpf_prog_run(),
> the ALU_END_TO_BE, ALU_END_TO_LE labels for details. There's a
> BPF_ENDIAN() macro used in the test suite and other places.

Are these hooked up to llvm intrinsics or so? If not, can I do that
through some kind of inline asm statement?

In the samples, I only see people doing

#define _htonl __builtin_bswap32

but I'm not even completely convinced that's correct, since it assumes
a little-endian host?

johannes