UNTITLED() LOCAL UNTITLED() NAME ng_netflow -- Cisco's NetFlow implementation SYNOPSIS #include <sys/types.h> #include <netinet/in.h> #include <netgraph/netflow/ng_netflow.h> DESCRIPTION The ng_netflow node implements Cisco's NetFlow export protocol on a router running FreeBSD. The ng_netflow node listens for incoming traffic and identifies unique flows in it. Flows are distinguished by endpoint IP ad- dresses, 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., plus a single hook named export. The node reads data on iface* hooks, and sends export datagrams to the export hook. In normal op- eration, the export hook is connected to the inet/dgram/udp hook of the ng_ksocket(4) 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 struct ng_netflow_info. NGM_NETFLOW_IFINFO Returns information about the ifaceN hook. The hook number is passed as an argument. NGM_NETFLOW_SETDLT Sets data link type on the ifaceN hook. Currently, supported types are raw IP datagrams and Ethernet. This messsage type uses 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 ifaceN hook must already be connected, otherwise mes- sage send operation will return an error. NGM_NETFLOW_SETIFINDEX In some cases, ng_netflow may be unable to determine the input in- terface index of a packet. This can happen if traffic enters the ng_netflow 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_iface(4). In this case, the input in- dex should be associated with a given hook. The interface's index can be determined via if_nametoindex(3) from userland. This mes- sage requires 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 ifaceN 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 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). ASCII CONTROL MESSAGES Most binary control messages have an ASCII equivalent. The supported ASCII commands are: NGM_NETFLOW_INFO "info" NGM_NETFLOW_IFINFO "ifinfo %u" NGM_NETFLOW_SETDLT "setdlt { iface = %u dlt = %u }" NGM_NETFLOW_SETIFINDEX "setifindex { iface = %u index = %u }" NGM_NETFLOW_SETTIMEOUTS "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: tee lower right connect fxp0: fxp0:lower upper left mkpeer fxp0:lower netflow right2left iface0 name fxp0:lower.right2left netflow 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 in- terfaces fxp0 and ng0. Note that the ng0: node in this example is con- nected to ng_tee(4). /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 } # Create tee on fxp0, and connect it to iface1 hook mkpeer fxp0: tee lower right connect fxp0: fxp0:lower upper left name fxp0:lower fxp0_tee connect fxp0_tee: netflow: right2left iface1 # 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 flowctl(4), netgraph(4), ng_ksocket(4), ng_tee(4), ngctl(8) http://www.cisco.com/warp/public/cc/pd/iosw/ioft/neflct/tech/napps_wp.htm AUTHORS The ng_netflow node type was written by Gleb Smirnoff <glebius@FreeBSD.org>, based on ng_ipacct written by Roman V. Palagin <romanp@unshadow.net>. BUGS The ng_netflow 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. FreeBSD 5.4 April 8, 2004 NG_NETFLOW(4)
NAME | SYNOPSIS | DESCRIPTION | HOOKS | CONTROL MESSAGES | ASCII CONTROL MESSAGES | SHUTDOWN | EXAMPLES | SEE ALSO | AUTHORS | BUGS
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