| Main index | Section 4 | Options |
#include <netgraph.h>
#include <netgraph/ng_etf.h>
Packets travelling in the other direction (towards the downstream hook) are also examined and filtered. If a packet has an ethertype that matches one of the values configured into the node, it must have arrived in on the hook for which that value was configured, otherwise it will be discarded. Ethertypes of values other than those configured by the control messages must have arrived via the nomatch hook.
| downstream | Typically this hook would be connected to a ng_ether(4) node, using the lower hook. |
| nomatch | Typically this hook would also be connected to an ng_ether(4) type node using the upper hook. |
| < any legal name> | |
| Any other hook name will be accepted and can be used as the match target of an ethertype. Typically this hook would be attached to a protocol handling node that requires and generates packets with a particular set of ethertypes. | |
| NGM_ETF_GET_STATUS ( getstatus) | |
| This command returns a struct ng_etfstat containing node statistics for packet counts. | |
| NGM_ETF_SET_FILTER ( setfilter) | |
Sets the a new ethertype filter into the node and specifies the hook to and
from which packets of that type should use.
The hook and ethertype
are specified in a structure of type
struct ng_etffilter:
struct ng_etffilter {
char matchhook[NG_HOOKSIZ]; /* hook name */
uint16_t ethertype; /* this ethertype to this hook */
};
| |
#!/bin/sh
ETHER_IF=fxp0
MATCH1=0x834
MATCH2=0x835
cat <<DONE >/tmp/xwert
# Make a new ethertype filter and attach to the Ethernet lower hook.
# first remove left over bits from last time.
shutdown ${ETHER_IF}:lower
mkpeer ${ETHER_IF}: etf lower downstream
# Give it a name to easily refer to it.
name ${ETHER_IF}:lower etf
# Connect the nomatch hook to the upper part of the same interface.
# All unmatched packets will act as if the filter is not present.
connect ${ETHER_IF}: etf: upper nomatch
DONE
ngctl -f /tmp/xwert
# something to set a hook to catch packets and show them.
echo "Unrecognised packets:"
nghook -a etf: newproto &
# Filter two random ethertypes to that hook.
ngctl 'msg etf: setfilter { matchhook="newproto" ethertype=${MATCH1} }
ngctl 'msg etf: setfilter { matchhook="newproto" ethertype=${MATCH2} }
| NG_ETF (4) | November 13, 2012 |
| Main index | Section 4 | Options |
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