diff options
author | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-08-26 14:41:41 +0200 |
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committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-08-29 20:30:28 +0200 |
commit | 13eeed6ea6f0a5d1353ee5ad14c4322695b4f59b (patch) | |
tree | dee935f0f40bb41399b8d5d0c8ab4f23e53fd7d3 /tests/py/ip | |
parent | 1ed9a3726c01fda218f37b7f4555c8b7106521ef (diff) |
src: add numgen expression
This new expression allows us to generate incremental and random numbers
bound to a specified modulus value.
The following rule sets the conntrack mark of 0 to the first packet seen,
then 1 to second packet, then 0 again to the third packet and so on:
# nft add rule x y ct mark set numgen inc mod 2
A more useful example is a simple load balancing scenario, where you can
also use maps to set the destination NAT address based on this new numgen
expression:
# nft add rule nat prerouting \
dnat to numgen inc mod 2 map { 0 : 192.168.10.100, 1 : 192.168.20.200 }
So this is distributing new connections in a round-robin fashion between
192.168.10.100 and 192.168.20.200. Don't forget the special NAT chain
semantics: Only the first packet evaluates the rule, follow up packets
rely on conntrack to apply the NAT information.
You can also emulate flow distribution with different backend weights
using intervals:
# nft add rule nat prerouting \
dnat to numgen inc mod 10 map { 0-5 : 192.168.10.100, 6-9 : 192.168.20.200 }
So 192.168.10.100 gets 60% of the workload, while 192.168.20.200 gets 40%.
We can also be mixed with dynamic sets, thus weight can be updated in
runtime.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'tests/py/ip')
-rw-r--r-- | tests/py/ip/numgen.t | 6 | ||||
-rw-r--r-- | tests/py/ip/numgen.t.payload | 24 |
2 files changed, 30 insertions, 0 deletions
diff --git a/tests/py/ip/numgen.t b/tests/py/ip/numgen.t new file mode 100644 index 00000000..9ce0c714 --- /dev/null +++ b/tests/py/ip/numgen.t @@ -0,0 +1,6 @@ +:pre;type nat hook prerouting priority 0 +*ip;test-ip4;pre + +ct mark set numgen inc mod 2;ok +dnat to numgen inc mod 2 map { 0 : 192.168.10.100, 1 : 192.168.20.200 };ok +dnat to numgen inc mod 10 map { 0-5 : 192.168.10.100, 6-9 : 192.168.20.200};ok diff --git a/tests/py/ip/numgen.t.payload b/tests/py/ip/numgen.t.payload new file mode 100644 index 00000000..cc07485b --- /dev/null +++ b/tests/py/ip/numgen.t.payload @@ -0,0 +1,24 @@ +# ct mark set numgen inc mod 2 +ip test-ip4 pre + [ numgen reg 1 = inc(2)] + [ ct set mark with reg 1 ] + +# dnat to numgen inc mod 2 map { 0 : 192.168.10.100, 1 : 192.168.20.200 } +__map%d x b +__map%d x 0 + element 00000000 : 640aa8c0 0 [end] element 01000000 : c814a8c0 0 [end] +ip test-ip4 pre + [ numgen reg 1 = inc(2)] + [ lookup reg 1 set __map%d dreg 1 ] + [ nat dnat ip addr_min reg 1 addr_max reg 0 ] + +# dnat to numgen inc mod 10 map { 0-5 : 192.168.10.100, 6-9 : 192.168.20.200} +__map%d test-ip4 f +__map%d test-ip4 0 + element 00000000 : 640aa8c0 0 [end] element 06000000 : c814a8c0 0 [end] element 0a000000 : 1 [end] +ip test-ip4 pre + [ numgen reg 1 = inc(10)] + [ byteorder reg 1 = hton(reg 1, 4, 4) ] + [ lookup reg 1 set __map%d dreg 1 ] + [ nat dnat ip addr_min reg 1 addr_max reg 0 ] + |