[EXTERNAL] [PATCH] examples/ipsec-secgw: add support for SM4-CBC cipher and SM3-HMAC auth

[Akhil Goyal]

> This patch adds support for Chinese cryptographic algorithms in the
> IPsec security gateway example application:
> 
> 1 Add SM4-CBC cipher algorithm support with 16-byte IV and key;
> 2 Add SM3-HMAC authentication algorithm support with 20-byte key;
> 3 Update SA configuration parsing to recognize "sm4-cbc" and "sm3-hmac"
> keywords;
> 4 Implement proper IV handling and authentication offset/length
> configuration.
> 
> These additions enable the IPsec security gateway to use Chinese
> national cryptographic standards for secure communications.
> 
> Signed-off-by: Sunyang Wu <sunyang.wu at jaguarmicro.com>
> ---
>  examples/ipsec-secgw/esp.c |  5 +++++
>  examples/ipsec-secgw/sa.c  | 17 ++++++++++++++++-
>  2 files changed, 21 insertions(+), 1 deletion(-)
please update documentation also
doc/guides/sample_app_ug/ipsec_secgw.rst