Cryptographic Acceleration: Difference between revisions
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== Supported hardware == | == Supported hardware == | ||
* Safenet SafeXcel 1741 and SafeXcel 1142 | |||
* Intel IXP465, IXP425 and IXP422 | |||
* Freescale SEC (Talitos) (this is also the bsec driver used on Linksys WRT54g, AsusWL500g) | |||
* PA Semi PWRficient DMA Crypto Engine | |||
* Intel EP80579 (Intel QuickAssist enabled EP80579 Integrated Processor Product Line) | |||
* PMC Sierra MSP-8520 (requires vendor-supplied source code for OCF) | |||
* Cavium Octeon (requires vendor-supplied source code for OCF) | |||
* Hifn 7951 and Hifn 7956 | |||
== Supported hardware via native kernel == | == Supported hardware via native kernel == |
Revision as of 23:38, 26 March 2014
Hardware Crypto Acceleration
There are two methods for crypto hardware acceleration. The most complete one is the Open Cryptographic Framework ("OCF"), a port of the OpenBSD code. A newer more native implementation is the CryptoAPI async interface. The latter implementation is still extremely limited. It does not have many drivers yet nor a rich API for userland. It is currently recommended to use OCF for crypto acceleration.
Libreswan supports OCF natively with the KLIPS IPsec stack. When using the Linux native NETKEY/XFRM IPsec stack, OCF acceleration is supported via the OCF cryptosoft.ko kernel module.
IPsec and IKE crypto acceleration
OCF provides kernel crypto acceleration for IPsec (ESP and AH) as well as userland crypto acceleration for IKE via the /dev/crypto interface. the kernel is responsible for the per-packet encryption and decryption, which is where the bulk of the cryptographic operations happen. The userland IKE daemon is responsible for the IKE encryption/decryption, but that usually involves only two to four packets per 1-8 hours. The libreswan pluto IKE daemon can use the /dev/crypto interface for IKE crypto hardware offload. Note that unless your CPU is severely limited in power, the overhead of /dev/crypto will not be worth it, and your userland will actually be slowed down. Support for /dev/crypto also requires a kernel recompile because it modifies some tty code. If only kernel level acceleration is needed, OCF can be build as a kernel module without requiring a recompile of the entire base kernel.
The /dev/crypto interface can however also be used by other userland based applications that use openssl. It is recommended to only bother with OCF userland support if there are crypto heavy userland applications besides the libreswan IKE daemon. For example, if the system also supports OpenVPN, it will be very useful to have OCF userland support in openssl.
For more information about OCF, see ocf-linux.sourceforge.net. To get an idea of the crypto acceleration see these OCF benchmarks
Supported hardware
- Safenet SafeXcel 1741 and SafeXcel 1142
- Intel IXP465, IXP425 and IXP422
- Freescale SEC (Talitos) (this is also the bsec driver used on Linksys WRT54g, AsusWL500g)
- PA Semi PWRficient DMA Crypto Engine
- Intel EP80579 (Intel QuickAssist enabled EP80579 Integrated Processor Product Line)
- PMC Sierra MSP-8520 (requires vendor-supplied source code for OCF)
- Cavium Octeon (requires vendor-supplied source code for OCF)
- Hifn 7951 and Hifn 7956
Supported hardware via native kernel
The OCF subsystem can interface with the native Linux kernel crypto acceleration system. It does so via the OCF cryptosoft kernel module.
- VIA Padlock (via cryptosoft) - AMD Geode LX (via cryptosoft) - SMP (multi-core) support (via cryptosoft)
Supported algorithms and ciphers with libreswan
- 3DES and 1DES - AES - SHA1 - MD5
Note that not all hardware implementations support all these algorithms and ciphers. Libreswan no longer supports 1DES because it is too insecure.
SMP support
The Linux NETKEY/XFRM native IPsec stack does not load balance a single IPsec SA over multiple CPU cores. Using the OCF cryptosoft driver, a single IPsec SA can be offloaded over multiple CPU's
Building libreswan with OCF support
Some OCF kernel builds are made available at libreswan.org, usually in the form of source and binary .deb or .rpm packages. the kernel packages provided support both kernel and userland OCF acceleration. You will also find patched openssl packages there which can be used in combination with openvpn to support hardware acceleration in userland.
Building kernel only OCF support as a module for running kernel
tar zxf ocf-linux-20120127.tar.gz cd ocf-linux-20120127/ocf make ocf_modules sudo make ocf_install OCF_DIR=`pwd`
You can test the OCF acceleration using a special benchmark module called ofc-bench. This is a kernel module that performs benchmarking when modprobe'd into the kernel. It will also fake an error to unload itself
modprobe ocf modprobe cryptosoft modprobe ocf-bench dmesg | tail -5
You should see something along the lines of:
[ 583.128741] OCF: 45133 requests of 1488 bytes in 251 jiffies (535.122 Mbps)
Building KLIPS with OCF support
To build libreswan KLIPS with OCF support, instead of using make module, use:
make KBUILD_EXTRA_SYMBOLS=$OCF_DIR/Module.symvers \ MODULE_DEF_INCLUDE=`pwd`/packaging/ocf/config-all.hmodules \ MODULE_DEFCONFIG=`pwd`/packaging/ocf/defconfig \ module sudo make KBUILD_EXTRA_SYMBOLS=$OCF_DIR/Module.symvers \ MODULE_DEF_INCLUDE=`pwd`/packaging/ocf/config-all.hmodules \ MODULE_DEFCONFIG=`pwd`/packaging/ocf/defconfig \ minstall
Building userland OCF support for IKE
Ensure that the system has /dev/crypto for userspace access to OCF:
mknod /dev/crypto c 10 70
Generate the kernel patches and apply the appropriate one.
cd ocf make patch
This will provide four files:
- linux-2.4-ocf.patch
- linux-2.6-ocf.patch
- linux-3.1-ocf.patch
- ocf-linux-base.patch
Depending on your kernel, pick the appropriate patch and apply it to your kernel, for example for a 3.1 kernel use:
cd linux-3.1 patch -p1 < linux-3.1-ocf.patch
For Linux 2.4 kernels on non-x86, you might need to issue: cp linux-2.X.x/include/asm-i386/kmap_types.h linux-2.X.x/include/asm-YYY |
To compile userland applications with OCF support, the cryptodev.h file needs to be installed on the system, for example in /usr/include/crypto/cryptodev.h
To compile the libreswan userland with OCF support, build with:
make HAVE_OCF=true programs install
The OCF source code comes with openssl patches as well, please see the OCF source for further instructions.
How to load the OCF modules into the kernel
Libreswan comes with the _stackmanager script that loads all kernel modules and sets various parameters. These include all the native CryptoAPI acceleration modules. It does not auto-detect OCF support on disk, so before starting _stackmanager, ensure that the system has loaded the OCF core kernel module:
modprobe ocf
Libreswan will detect OCF support and load the userland (cryptodev) and software driver (cryptosoft)
To load any of the OCF hardware drivers, ensure you load the appropriate hardware driver, eg one of:
modprobe safe modprobe hifn7751 modprobe ixp4xx ...
You might wish to change _stackmanager to not load the cryptosoft module if you have native OCF hardware driver support. In some cases the software driver has accidentally gained preference over a hardware driver |
Debugging OCF
To enable debugging (which will ruin your acceleration gains!) you can issue some of the following commands based on your hardware/software:
echo 1 > /sys/module/ocf/parameters/crypto_debug echo 1 > /sys/module/cryptodev/parameters/cryptodev_debug echo 1 > /sys/module/cryptosoft/parameters/swcr_debug echo 1 > /sys/module/hifn7751/parameters/hifn_debug echo 1 > /sys/module/safe/parameters/safe_debug echo 1 > /sys/module/ixp4xx/parameters/ixp_debug
OCF benchmarking
The ocf-bench driver accepts the following parameters:
- request_q_len - Maximum number of outstanding requests to OCF - request_num - run for at least this many requests - request_size - size of each request (multiple of 16 bytes recommended) - request_batch - enable OCF request batching - request_cbimm - enable OCF immediate callback on completion
An example benchmark use:
modprobe ocf-bench request_size=1024 request_cbimm=0 dmesg |tail -5
OCF KLIPS tuning
The following parameters are managed by _stackmanager but can be changed to suit your specific need based on the hardware capabilities of your platform:
- /sys/module/ocf/parameters/crypto_q_max - /sys/module/ipsec/parameters/ipsec_irs_cache_allocated_max - /sys/module/ipsec/parameters/ipsec_ixs_cache_allocated_max