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ng_netflow (4)
  • >> ng_netflow (4) ( FreeBSD man: Специальные файлы /dev/* )

  • BSD mandoc
     

    NAME

    ng_netflow
    
     - Cisco's NetFlow implementation
    
     
    

    SYNOPSIS

       #include <sys/types.h>
       #include <netinet/in.h>
       #include <netgraph/netflow/ng_netflow.h>
     

    DESCRIPTION

    The node implements Cisco's NetFlow export protocol on a router running Fx . The node listens for incoming traffic and identifies unique flows in it. Flows are distinguished by endpoint IP addresses, TCP/UDP port numbers, ToS and input interface. Expired flows are exported out of the node in NetFlow version 5 UDP datagrams. Expiration reason can be one of the following:

    RST or FIN TCP segment.
    Active timeout.
    Flows cannot live more than the specified period of time. The default is 1800 seconds (30 minutes).
    Inactive timeout.
    A flow was inactive for the specified period of time. The default is 15 seconds.

    Export information is stored in NetFlow version 5 datagrams.  

    HOOKS

    This node type supports up to NG_NETFLOW_MAXIFACES hooks named iface0 , iface1 etc., and the same number of hooks named out0 , out1 etc., plus a single hook named export The node does NetFlow accounting of data received on iface* hooks. If corresponding out hook is connected, unmodified data is bypassed to it, otherwise data is freed. If data is received on out hook, it is bypassed to corresponding iface hook without any processing. When full export datagram is built it is sent to the export hook. In normal operation, the export hook is connected to the inet/dgram/udp hook of the ng_ksocket4 node.  

    CONTROL MESSAGES

    This node type supports the generic control messages, plus the following:

    NGM_NETFLOW_INFO
    Returns some node statistics and the current timeout values in a Vt struct ng_netflow_info .
    NGM_NETFLOW_IFINFO
    Returns information about the iface N hook. The hook number is passed as an argument.
    NGM_NETFLOW_SETDLT
    Sets data link type on the iface N hook. Currently, supported types are raw IP datagrams and Ethernet. This message type uses Vt struct ng_netflow_setdlt as an argument:
    struct ng_netflow_setdlt {
            uint16_t iface;         /* which iface to operate on */
            uint8_t  dlt;           /* DLT_XXX from bpf.h */
    };
    

    The requested iface N hook must already be connected, otherwise message send operation will return an error.

    NGM_NETFLOW_SETIFINDEX
    In some cases, may be unable to determine the input interface index of a packet. This can happen if traffic enters the node before it comes to the system interface's input queue. An example of such a setup is capturing a traffic between synchronous data line and ng_iface4. In this case, the input index should be associated with a given hook. The interface's index can be determined via if_nametoindex3 from userland. This message requires Vt struct ng_netflow_setifindex as an argument:
    struct ng_netflow_setifindex {
            u_int16_t iface;        /* which iface to operate on */
            u_int16_t index;        /* new index */
    };
    

    The requested iface N hook must already be connected, otherwise the message send operation will return an error.

    NGM_NETFLOW_SETTIMEOUTS
    Sets values in seconds for NetFlow active/inactive timeouts. This message requires Vt struct ng_netflow_settimeouts as an argument:
    struct ng_netflow_settimeouts {
            uint32_t        inactive_timeout;
            uint32_t        active_timeout;
    };
    
    NGM_NETFLOW_SHOW
    This control message asks a node to dump the entire contents of the flow cache. It is called from flowctl(8), not directly from ngctl(8). See also Sx BUGS section.

     

    ASCII CONTROL MESSAGES

    Most binary control messages have an ASCII equivalent. The supported ASCII commands are:

    NGM_NETFLOW_INFO
    Qq Li info
    NGM_NETFLOW_IFINFO
    Qq Li ifinfo %u
    NGM_NETFLOW_SETDLT
    Qq Li setdlt { iface = %u dlt = %u }
    NGM_NETFLOW_SETIFINDEX
    Qq Li setifindex { iface = %u index = %u }
    NGM_NETFLOW_SETTIMEOUTS
    Qq Li settimeouts { inactive = %u active = %u }

     

    SHUTDOWN

    This node shuts down upon receipt of a NGM_SHUTDOWN control message, or when all hooks have been disconnected.  

    EXAMPLES

    The simplest possible configuration is one Ethernet interface, where flow collecting is enabled.
    /usr/sbin/ngctl -f- <<-SEQ
            mkpeer fxp0: netflow lower iface0
            name fxp0:lower netflow
            connect fxp0: netflow: upper out0
            mkpeer netflow: ksocket export inet/dgram/udp
            msg netflow:export connect inet/10.0.0.1:4444
    SEQ
    

    This is a more complicated example of a router with 2 NetFlow-enabled interfaces fxp0 and ng0 Note that the ng0: node in this example is connected to ng_tee4. The latter sends us a copy of IP packets, which we analyze and free. On fxp0: we do not use tee, but send packets back to ether node.

    /usr/sbin/ngctl -f- <<-SEQ
            # connect ng0's tee to iface0 hook
            mkpeer ng0:inet netflow right2left iface0
            name ng0:inet.right2left netflow
            # set DLT to raw mode
            msg netflow: setdlt { iface=0 dlt=12 }
            # set interface index (5 in this example)
            msg netflow: setifindex { iface=0 index=5 }
    
            # Connect fxp0: to iface1 and out1 hook
            connect fxp0: netflow: lower iface1
            connect fxp0: netflow: upper out1
    
            # Create ksocket node on export hook, and configure it
            # to send exports to proper destination
            mkpeer netflow: ksocket export inet/dgram/udp
            msg netflow:export connect inet/10.0.0.1:4444
    SEQ
    
     

    SEE ALSO

    netgraph(4), ng_ether4, ng_iface4, ng_ksocket4, ng_tee4, flowctl(8), ngctl(8)

    http://www.cisco.com/univercd/cc/td/doc/cisintwk/intsolns/netflsol/nfwhite.htm  

    AUTHORS

    An -nosplit The node type was written by An Gleb Smirnoff Aq [email protected] , based on ng_ipacct written by An Roman V. Palagin Aq [email protected] .  

    BUGS

    Cache snapshot obtained via NGM_NETFLOW_SHOW command may lack some percentage of entries under severe load.

    The node type does not fill in AS numbers. This is due to the lack of necessary information in the kernel routing table. However, this information can be injected into the kernel from a routing daemon such as GNU Zebra. This functionality may become available in future releases.


     

    Index

    NAME
    SYNOPSIS
    DESCRIPTION
    HOOKS
    CONTROL MESSAGES
    ASCII CONTROL MESSAGES
    SHUTDOWN
    EXAMPLES
    SEE ALSO
    AUTHORS
    BUGS


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