• David S. Miller's avatar
    ipv4: Create and use fib_compute_spec_dst() helper. · 35ebf65e
    David S. Miller authored
    The specific destination is the host we direct unicast replies to.
    Usually this is the original packet source address, but if we are
    responding to a multicast or broadcast packet we have to use something
    different.
    
    Specifically we must use the source address we would use if we were to
    send a packet to the unicast source of the original packet.
    
    The routing cache precomputes this value, but we want to remove that
    precomputation because it creates a hard dependency on the expensive
    rpfilter source address validation which we'd like to make cheaper.
    
    There are only three places where this matters:
    
    1) ICMP replies.
    
    2) pktinfo CMSG
    
    3) IP options
    
    Now there will be no real users of rt->rt_spec_dst and we can simply
    remove it altogether.
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    35ebf65e
ip_fib.h 7.26 KB