[strongSwan] Enabling AES-NI in strongswan

[Jeff Leung]

> Hi,
> 
> i am looking for ways to improve the throughput while using the 
> strongswan IPSEC.
> 
> I read that AES-GCM provides excellent throughput over default 
> AES-CBC-
> 128 when used with AES-NI support in intel processors.
> 
> 
> i want to enable AES-GCM128 cipher in my xeon E5 processor, and from 
> looking at the Intel white paper, it mentioned about using "Linux 
> AES-NI- GCM Crypto Plug-in" to enable this support.
> It described about a patch to existing AES-NI driver file, called 
> aesni- intel_glue.c and aesni-intel_asm.s.
As strongSwan uses XFRM stack by default on Linux and XFRM being a kernel level implementation, it has the capability of using AES-NI at the driver level. However there was a bug in pre 4.1 kernels where AES-NI does not work right for GCM operations.

> 
> 
> Paper: http://www.intel.com/content/www/us/en/intelligent-
> systems/wireless-infrastructure/aes-ipsec-performance-linux-paper.html
> 
> 
> 1. There is strongswan plugin for intel AES-NI, Can somebody 
> confirm/tell me a way to find if this is the same plugin as the one 
> mentioned in intel Doc ? To me it looks like that, but i wanted to 
> check with someone who might be already using this.
iirc that is meant for userspace mode of operation only. XFRM stack still uses the kernel cryptographic drivers for encrypting and decrypting ESP payloads.

> 2.  Is there some other way to get higher throughput ?
> pcrypt module is available, will it work with AES-GCM ?
> 
> 
> libstrongswan plugin :
> 
> aesni - Intel AES-NI crypto plugin (since 5.3.1 
> <https://wiki.strongswan.org/versions/56> )
> 
> 
> 
> 
> The new aesni plugin provides CBC, CTR, XCBC, CMAC, CCM and GCM crypto 
> primitives for AES-128/192/256.
> 
> The plugin requires AES-NI and PCLMULQDQ instructions and works on 
> both
> x86 and x64 architectures. It provides superior crypto performance in 
> userland without any external libraries.
> 
> 
> Thanks
> kapil.
> 
> 
> 
>