ipv4: Set the routing scope properly in ip_route_output_ports().
Set scope automatically in ip_route_output_ports() (using the socket SOCK_LOCALROUTE flag). This way, callers don't have to overload the tos with the RTO_ONLINK flag, like RT_CONN_FLAGS() does. For callers that don't pass a struct sock, this doesn't change anything as the scope is still set to RT_SCOPE_UNIVERSE when sk is NULL. Callers that passed a struct sock and used RT_CONN_FLAGS(sk) or RT_CONN_FLAGS_TOS(sk, tos) for the tos are modified to use ip_sock_tos(sk) and RT_TOS(tos) respectively, as overloading tos with the RTO_ONLINK flag now becomes unnecessary. In drivers/net/amt.c, all ip_route_output_ports() calls use a 0 tos parameter, ignoring the SOCK_LOCALROUTE flag of the socket. But the sk parameter is a kernel socket, which doesn't have any configuration path for setting SOCK_LOCALROUTE anyway. Therefore, ip_route_output_ports() will continue to initialise scope with RT_SCOPE_UNIVERSE and amt.c doesn't need to be modified. Also, remove RT_CONN_FLAGS() and RT_CONN_FLAGS_TOS() from route.h as these macros are now unused. The objective is to eventually remove RTO_ONLINK entirely to allow converting ->flowi4_tos to dscp_t. This will ensure proper isolation between the DSCP and ECN bits, thus minimising the risk of introducing bugs where TOS values interfere with ECN. Signed-off-by: Guillaume Nault <gnault@redhat.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/dacfd2ab40685e20959ab7b53c427595ba229e7d.1707496938.git.gnault@redhat.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>
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