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Jan 2, 2024
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Deduplicate Iptables Rules with Dynamic ASG's #101

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42fe471
Add iptables-rules deduplication step
klapkov Nov 14, 2023
90a19d2
Clean up a bit
klapkov Nov 14, 2023
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79 changes: 79 additions & 0 deletions src/code.cloudfoundry.org/cni-wrapper-plugin/fakes/rule_converter.go
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1 change: 1 addition & 0 deletions src/code.cloudfoundry.org/cni-wrapper-plugin/netrules/netout.go
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ const secondInMillis = 1000
type ruleConverter interface {
Convert(Rule, string, bool) []rules.IPTablesRule
BulkConvert([]Rule, string, bool) []rules.IPTablesRule
DeduplicateRules([]rules.IPTablesRule) []rules.IPTablesRule
}

type OutConn struct {
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2 changes: 2 additions & 0 deletions src/code.cloudfoundry.org/cni-wrapper-plugin/netrules/netout_chain.go
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Expand Up @@ -62,6 +62,8 @@ func (c *NetOutChain) IPTablesRules(containerHandle string, containerWorkload st
}

iptablesRules := c.Converter.BulkConvert(ruleSpec, logChain, c.ASGLogging)
iptablesRules = c.Converter.DeduplicateRules(iptablesRules)

iptablesRules = append(iptablesRules, c.denyNetworksRules(containerWorkload)...)

if c.Conn.Limit || c.Conn.DryRun {
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2 changes: 1 addition & 1 deletion src/code.cloudfoundry.org/cni-wrapper-plugin/netrules/netout_chain_test.go
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Expand Up @@ -77,7 +77,7 @@ var _ = Describe("NetOutChain", func() {
}

converter.BulkConvertReturns(genericRules)

converter.DeduplicateRulesReturns(genericRules)
})

It("prepends allow rules to the container's netout chain", func() {
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16 changes: 16 additions & 0 deletions src/code.cloudfoundry.org/cni-wrapper-plugin/netrules/rule_converter.go
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Expand Up @@ -59,6 +59,22 @@ func (c *RuleConverter) BulkConvert(ruleSpec []Rule, logChainName string, global
return iptablesRules
}

func (c *RuleConverter) DeduplicateRules(iptablesRules []rules.IPTablesRule) []rules.IPTablesRule {
keys := make(map[string]bool)
deduped_rules := []rules.IPTablesRule{}
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@PlamenDoychev PlamenDoychev Nov 14, 2023

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Aren't we creating a copy of the rules set here? What would be the memory impact, we have seen cases with millions of rules?

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@klapkov klapkov Nov 14, 2023 •
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We create a map, in which we use the rules as keys and the value is true or false. If on the current iteration of the rules list we have a rule which is not part of the keys map, we add it to keys and set the value to true. This way if a duplicate of that rule is present, we will skip adding it to the dedupedRules, since the value of that rule is set to true. As to the memory concern, this way of removing duplicates was the one I saw used the most in go. Honestly I do not know how will this impact performance. Open to suggestions here


for _, rule := range iptablesRules {
key := strings.Join(rule, " ")
if !keys[key] {

keys[key] = true
deduped_rules = append(deduped_rules, rule)
}
}

return deduped_rules
}

func (c *RuleConverter) Convert(rule Rule, logChainName string, globalLogging bool) []rules.IPTablesRule {
ruleSpec := []rules.IPTablesRule{}
for _, network := range rule.Networks() {
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58 changes: 58 additions & 0 deletions src/code.cloudfoundry.org/cni-wrapper-plugin/netrules/rule_converter_test.go
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Expand Up @@ -426,4 +426,62 @@ var _ = Describe("RuleConverter", func() {
})

})
Describe("DeduplicateRules", func() {
var unfiltered_rules []rules.IPTablesRule
Context("when there are duplicate iptables rules", func() {
BeforeEach(func() {
rule1 := rules.IPTablesRule{
"-m", "iprange", "-p", "tcp",
"--dst-range", "1.1.1.1-2.2.2.2",
"-m", "tcp", "--destination-port", "9000:9999",
"--jump", "ACCEPT",
}
rule2 := rules.IPTablesRule{
"-m", "iprange", "-p", "tcp",
"--dst-range", "1.1.1.1-2.2.2.2",
"-m", "tcp", "--destination-port", "9000:9999",
"--jump", "ACCEPT",
}
rule3 := rules.IPTablesRule{
"-m", "iprange", "-p", "tcp",
"--dst-range", "3.3.3.3-4.4.4.4",
"-m", "tcp", "--destination-port", "9000:9999",
"--jump", "ACCEPT",
}
rule4 := rules.IPTablesRule{
"-m", "iprange", "-p", "tcp",
"--dst-range", "1.1.1.1-2.2.2.2",
"-m", "tcp", "--destination-port", "9000:9999",
"--jump", "ACCEPT",
}
rule5 := rules.IPTablesRule{
"-m", "iprange", "-p", "tcp",
"--dst-range", "4.4.4.4-5.5.5.5",
"-m", "tcp", "--destination-port", "9000:9999",
"--jump", "ACCEPT",
}

unfiltered_rules = []rules.IPTablesRule{rule1, rule2, rule3, rule4, rule5}
})

It("removes the duplicate iptables rules", func() {
deduped_rules := converter.DeduplicateRules(unfiltered_rules)

Expect(deduped_rules).To(ConsistOf(
rules.IPTablesRule{"-m", "iprange", "-p", "tcp",
"--dst-range", "1.1.1.1-2.2.2.2",
"-m", "tcp", "--destination-port", "9000:9999",
"--jump", "ACCEPT"},
rules.IPTablesRule{"-m", "iprange", "-p", "tcp",
"--dst-range", "4.4.4.4-5.5.5.5",
"-m", "tcp", "--destination-port", "9000:9999",
"--jump", "ACCEPT"},
rules.IPTablesRule{"-m", "iprange", "-p", "tcp",
"--dst-range", "3.3.3.3-4.4.4.4",
"-m", "tcp", "--destination-port", "9000:9999",
"--jump", "ACCEPT"},
))
})
})
})
})