netdev - Same data to several sockets with just one syscall ?

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-next>] [day] [month] [year] [list]

Date:	Fri, 12 Feb 2016 09:53:37 +0100
From:	Claudio Scordino <claudio@...dence.eu.com>
To:	netdev@...r.kernel.org
Subject: Same data to several sockets with just one syscall ?

Hi all.

Suppose I have an application that needs to send the very same data to
several sockets already connected. In this case, the application has
to call the sendto() syscall several times:

      for(...)
               sendto(...)

This makes the application waste time in entering/exiting the kernel
level several times.
Moreover, if I'm not wrong, the kernel is free to execute pending work
(e.g., softirqs) when returning from a syscall, making the application
experience further latency.

I therefore wonder if a mechanism exists for sending the data to
several sockets using just a single syscall. If not, has anybody ever
thought about adding a syscall like the following ?

      sendto-multicast(..., int number_of_sockets, int* const sockets [])

I can't see any obvious reason why such an approach could be wrong.

Many thanks,

               Claudio