• Thomas Graf's avatar
    dst: Metadata destinations · f38a9eb1
    Thomas Graf authored
    Introduces a new dst_metadata which enables to carry per packet metadata
    between forwarding and processing elements via the skb->dst pointer.
    
    The structure is set up to be a union. Thus, each separate type of
    metadata requires its own dst instance. If demand arises to carry
    multiple types of metadata concurrently, metadata dst entries can be
    made stackable.
    
    The metadata dst entry is refcnt'ed as expected for now but a non
    reference counted use is possible if the reference is forced before
    queueing the skb.
    
    In order to allow allocating dsts with variable length, the existing
    dst_alloc() is split into a dst_alloc() and dst_init() function. The
    existing dst_init() function to initialize the subsystem is being
    renamed to dst_subsys_init() to make it clear what is what.
    
    The check before ip_route_input() is changed to ignore metadata dsts
    and drop the dst inside the routing function thus allowing to interpret
    metadata in a later commit.
    Signed-off-by: default avatarThomas Graf <tgraf@suug.ch>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    f38a9eb1
dst.h 12.2 KB