• Jamal Hadi Salim's avatar
    net sched actions: Add support for user cookies · 1045ba77
    Jamal Hadi Salim authored
    Introduce optional 128-bit action cookie.
    Like all other cookie schemes in the networking world (eg in protocols
    like http or existing kernel fib protocol field, etc) the idea is to save
    user state that when retrieved serves as a correlator. The kernel
    _should not_ intepret it.  The user can store whatever they wish in the
    128 bits.
    
    Sample exercise(showing variable length use of cookie)
    
    .. create an accept action with cookie a1b2c3d4
    sudo $TC actions add action ok index 1 cookie a1b2c3d4
    
    .. dump all gact actions..
    sudo $TC -s actions ls action gact
    
        action order 0: gact action pass
         random type none pass val 0
         index 1 ref 1 bind 0 installed 5 sec used 5 sec
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0
        cookie a1b2c3d4
    
    .. bind the accept action to a filter..
    sudo $TC filter add dev lo parent ffff: protocol ip prio 1 \
    u32 match ip dst 127.0.0.1/32 flowid 1:1 action gact index 1
    
    ... send some traffic..
    $ ping 127.0.0.1 -c 3
    PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
    64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.020 ms
    64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.027 ms
    64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.038 ms
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    1045ba77
pkt_cls.h 12.4 KB