On 8/21/24 6:52 AM, Ido Schimmel wrote:
> tl;dr - This patchset starts to unmask the upper DSCP bits in the IPv4
> flow key in preparation for allowing IPv4 FIB rules to match on DSCP. No
> functional changes are expected.
>
> The TOS field in the IPv4 flow key ('flowi4_tos') is used during FIB
> lookup to match against the TOS selector in FIB rules and routes.
>
> It is currently impossible for user space to configure FIB rules that
> match on the DSCP value as the upper DSCP bits are either masked in the
> various call sites that initialize the IPv4 flow key or along the path
> to the FIB core.
>
> In preparation for adding a DSCP selector to IPv4 and IPv6 FIB rules, we
> need to make sure the entire DSCP value is present in the IPv4 flow key.
> This patchset starts to unmask the upper DSCP bits in the various places
> that invoke the core FIB lookup functions directly (patches #1-#7) and
> in the input route path (patches #8-#12). Future patchsets will do the
> same in the output route path.
>
> No functional changes are expected as commit 1fa3314c14c6 ("ipv4:
> Centralize TOS matching") moved the masking of the upper DSCP bits to
> the core where 'flowi4_tos' is matched against the TOS selector.
>
for the set:
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
