Re: [dpdk-users] AES GCM PMD Driver IV length support

["Trahe, Fiona" <fiona.trahe@intel.com>]

Hi Nubin,

> -----Original Message-----
> From: users [mailto:users-bounces@dpdk.org] On Behalf Of Nubin Stanley
> Sent: Thursday, December 8, 2016 9:21 AM
> To: users@dpdk.org
> Cc: martin.varghese@nokia.com
> Subject: [dpdk-users] AES GCM PMD Driver IV length support
> 
> Hi All
> 
> 
> 
> I see that the only IV size supported in AES GCM driver is 16bytes. For
> using AES-GCM-128  in IPsec, the IV length  has to be   12 bytes ( 4 (salt)
> + 8 (iv)).
> 
> 
> How should I handle this IPsec case with AES GCM PMD driver.
> 
> 
> 
> .op = RTE_CRYPTO_OP_TYPE_SYMMETRIC,
> 
>         {.sym = {
> 
>             .xform_type = RTE_CRYPTO_SYM_XFORM_CIPHER,
> 
>             {.cipher = {
> 
>                 .algo = RTE_CRYPTO_CIPHER_AES_GCM,
> 
>                 .block_size = 16,
> 
>                 .key_size = {
> 
>                     .min = 16,
> 
>                     .max = 16,
> 
>                     .increment = 0
> 
>                 },
> 
>                 .iv_size = {
> 
>                     .min = 16,
> 
>                     .max = 16,
> 
>                     .increment = 0
> 
>                 }
> 
>             }, }
> 
>         }, }
> 
> 
> 
> Regards,
> Nubin Stanley


I found the following code in the PMD to handle an iv length of 12, so this looks like a bug in the capability data.
/* sanity checks */
	if (op->cipher.iv.length != 16 && op->cipher.iv.length != 12 &&
			op->cipher.iv.length != 0) {
		GCM_LOG_ERR("iv");
		return -1;
	}

	/*
	 * GCM working in 12B IV mode => 16B pre-counter block we need
	 * to set BE LSB to 1, driver expects that 16B is allocated
	 */
	if (op->cipher.iv.length == 12) {
		op->cipher.iv.data[15] = 1;
	}

Have you tried passing a 12-byte iv to the driver ?