Re: [Ocf-linux-users] The development problem of developing an OCF driver, could you please give me some hint?

[David M. <dav...@mc...>]

Jivin Liu Hui lays it down ...
> Hi David and all,
> 
> I am developing an OCF-LINUX-DRIVER for one chip. I got some problems, could you please take a look in it?
> I started with ocfnull driver template and only added CRYPTO_DES_CBC algorithm to the driver:

ocfnull is probably not a good example to follow if you are doing a real HW
driver.  Be sure to look at some of the others as well once you get into it.

> crypto_register(cp8_id, CRYPTO_DES_CBC, 0, 0);
> 
> More alogrithm will be added after this simplest one works.
> 
> In order to make cryptosoft driver not compete with my driver, I comment the CBC-DES in cryptosoft driver, like this:
> // [CRYPTO_DES_CBC]         = { cbc(des),          SW_TYPE_BLKCIPHER, },
> 
> And I also insmod my driver before cryptosoft.
> In my opnion, if there are DES-CBC request, they will be sent to my driver.
> 
> The ocf-linux dispatch work seem works. After I run 'service ipsec start', the newsessson routine in my driver was called, here is the dmesg print:
> cp8_newsession()
> cp8_newsession key:cri->cri_klen=64,(cri->cri_klen + 7)/8=8
>     0x30 0x31 0x32 0x33 0x34 0x35 0x36 0x37
> cp8_freesession()
> 
> BUT, after I want to set up a connecton by 'ipsec auto --up net-to-net', error happended:
> 003 ERROR: "net-to-net" #5: pfkey write() of K_SADB_ADD message 19 for Add SA esp.1e94ffe@172.22.14.5 failed. Errno 71: Protocol error
> 
> The dmesg print show:
> KLIPS klips_debug:ipsec_alg_enc_key_create: NULL ipsec_alg_enc object
> KLIPS pfkey_add_parse: not successful for SA:  (error), deleting
> 
> It seems that openswan can't find an ipsec_alg_enc object to create a key.
> 
> But if I use DES-CBC algorithm of cryptosoft driver, this error will disappear.
> I can't understand why the key generation is related with ocf-driver because ocf-driver is not in charge of generate key.
> And I can't see the different between my driver and cryptosoft driver, i.e. why cryptosoft driver works and mine failed?
> 
> Could you please give me some hint? 

It is possibly because openswan wants to do a combination hash+crypto.  I am
not sure on this it seems likely given what you have tried.  The other
option may be that ocfnull cut corners that a real driver cannot.

You have a couple of options,  test your driver using "cryptotest"
initially.  That will get around the hash+cipher problems.

Second,  mod the ocfbench driver to test DES and do no hashing and try that
for in kernel testing.

Once you have all that and you think you are ready to roll we can look at
where it should go next.  Does your hardware support hashes ?  If so then
get that implemented next and you should be done.  If not perhaps we can
look at how ocf spreads requests across multiple drivers (ie., hashes on one
driver and ciphers on another).

Cheers,
Davidm

-- 
David McCullough,      dav...@mc...,  Ph:+61 734352815
McAfee - SnapGear      http://www.mcafee.com         http://www.uCdot.org