Difference between revisions of "Math operations"

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(create page with basic content)
 
(add hashing section)
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mark set numgen random mod 50 offset 20
 
mark set numgen random mod 50 offset 20
 
mark set numgen inc mod 100
 
mark set numgen inc mod 100
 +
}
 +
}
 +
</source>
 +
 +
= Hashing =
 +
 +
nftables support hashing of any arbitrary key combination:
 +
 +
<source>
 +
table ip t {
 +
chain c {
 +
mark set jhash ip saddr mod 2
 +
mark set jhash ip saddr . tcp dport mod 2
 +
mark set jhash ip saddr . tcp dport . iiftype mod 2
 
}
 
}
 
}
 
}
 
</source>
 
</source>

Revision as of 13:49, 5 January 2017

nftables includes some interesting math operations generators which can be used to perform advanced operations like Load balancing.

Number generator

The number generator statement has these options:

  • type: inc/random.
  • modulus: maximun number
  • offset: from what value you want to start from

Some examples, distributing marks to packets:

table ip t {
	chain c {
		mark set numgen inc mod 4 offset 3
		mark set numgen random mod 50 offset 20
		mark set numgen inc mod 100
	}
}

Hashing

nftables support hashing of any arbitrary key combination:

table ip t {
	chain c {
		mark set jhash ip saddr mod 2
		mark set jhash ip saddr . tcp dport mod 2
		mark set jhash ip saddr . tcp dport . iiftype mod 2
	}
}