[strongSwan] Android supported cipher suites

[Tobias Brunner]

Hi Mark,

> ESP:AES_GCM_16_128/AES_GCM_16_256/NO_EXT_SEQ,
> ESP:AES_CBC_128/HMAC_SHA2_256_128/NO_EXT_SEQ,
> ESP:AES_CBC_256/HMAC_SHA2_384_192/NO_EXT_SEQ,
> ESP:AES_CBC_128/AES_CBC_192/AES_CBC_256/HMAC_SHA1_96/
>     HMAC_SHA2_256_128/HMAC_SHA2_384_192/HMAC_SHA2_512_256/NO_EXT_SEQ

These are the ESP proposals for the first CHILD_SA that is negotiated
with the IKE_SA, so no DH groups are included.  The full proposal used
when the CHILD_SA is rekeyed looks like this:

ESP:AES_GCM_16_128/AES_GCM_16_256/ECP_256/NO_EXT_SEQ,
ESP:AES_CBC_128/HMAC_SHA2_256_128/ECP_256/MODP_3072/NO_EXT_SEQ,
ESP:AES_CBC_256/HMAC_SHA2_384_192/ECP_521/MODP_8192/NO_EXT_SEQ,
ESP:AES_CBC_128/AES_CBC_192/AES_CBC_256/HMAC_SHA1_96/
    HMAC_SHA2_256_128/HMAC_SHA2_384_192/HMAC_SHA2_512_256/
    ECP_256/ECP_384/ECP_521/MODP_2048/MODP_3072/
    MODP_4096/MODP_1024/NO_EXT_SEQ
ESP:AES_GCM_16_128/AES_GCM_16_256/NO_EXT_SEQ,
ESP:AES_CBC_128/HMAC_SHA2_256_128/NO_EXT_SEQ,
ESP:AES_CBC_256/HMAC_SHA2_384_192/NO_EXT_SEQ,
ESP:AES_CBC_128/AES_CBC_192/AES_CBC_256/HMAC_SHA1_96/
    HMAC_SHA2_256_128/HMAC_SHA2_384_192/HMAC_SHA2_512_256/NO_EXT_SEQ

So if the gateway's ESP proposal is configured with DH group(s) PFS will
be used.

Regards,
Tobias