> 
> The second member of the union should be a variable length array [] of
> struct nsh_md2_tlv
> 
> struct nsh_hdr {
>     ovs_be16 ver_flags_ttl_len;
>     uint8_t mdtype;
>     uint8_t np;
>     ovs_16aligned_be32 path_hdr;
>     union {
>         struct nsh_md1_ctx md1;
>         struct nsh_md2_tlv md2[];
>     };
> };
> 
> That was the original design before Ben removed it due to missing support
> in Microsoft compiler.
> For the Kernel datapath we should go back to that.
> 
> I wonder about the possible 16-bit alignment of the 32-bit fields, though.
> How is that handled in the kernel? Also struct nsh_md1_ctx has 32-bit
> members, which might not be 32-bit aligned in the packet.
> 

One afterthought: 

I think it would be good to add another member to the union to represent 
unstructured context headers as used, e.g., in the context of push_nsh.

struct nsh_hdr {
    ovs_be16 ver_flags_ttl_len;
    uint8_t mdtype;
    uint8_t np;
    ovs_16aligned_be32 path_hdr;
    union {
        uint8_t ctx_headers[];
        struct nsh_md1_ctx md1;
        struct nsh_md2_tlv md2[];
    };
};


Reply via email to