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Avoid allocations when parsing iptables

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This commit is contained in:
wojtekt
2018-07-06 13:34:15 +02:00
parent cb9ddd3456
commit 6e50f39dbd
6 changed files with 63 additions and 41 deletions
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44
pkg/proxy/iptables/proxier.go
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@@ -403,16 +403,16 @@ func CleanupLeftovers(ipt utiliptables.Interface) (encounteredError bool) {
for _, chain := range []utiliptables.Chain{kubeServicesChain, kubeNodePortsChain, kubePostroutingChain, KubeMarkMasqChain} {
if _, found := existingNATChains[chain]; found {
chainString := string(chain)
writeLine(natChains, existingNATChains[chain]) // flush
writeLine(natRules, "-X", chainString) // delete
writeBytesLine(natChains, existingNATChains[chain]) // flush
writeLine(natRules, "-X", chainString) // delete
}
}
// Hunt for service and endpoint chains.
for chain := range existingNATChains {
chainString := string(chain)
if strings.HasPrefix(chainString, "KUBE-SVC-") || strings.HasPrefix(chainString, "KUBE-SEP-") || strings.HasPrefix(chainString, "KUBE-FW-") || strings.HasPrefix(chainString, "KUBE-XLB-") {
writeLine(natChains, existingNATChains[chain]) // flush
writeLine(natRules, "-X", chainString) // delete
writeBytesLine(natChains, existingNATChains[chain]) // flush
writeLine(natRules, "-X", chainString) // delete
}
}
writeLine(natRules, "COMMIT")
@@ -426,7 +426,7 @@ func CleanupLeftovers(ipt utiliptables.Interface) (encounteredError bool) {
}
// Flush and remove all of our "-t filter" chains.
iptablesData = bytes.NewBuffer(nil)
iptablesData.Reset()
if err := ipt.SaveInto(utiliptables.TableFilter, iptablesData); err != nil {
glog.Errorf("Failed to execute iptables-save for %s: %v", utiliptables.TableFilter, err)
encounteredError = true
@@ -438,7 +438,7 @@ func CleanupLeftovers(ipt utiliptables.Interface) (encounteredError bool) {
for _, chain := range []utiliptables.Chain{kubeServicesChain, kubeExternalServicesChain, kubeForwardChain} {
if _, found := existingFilterChains[chain]; found {
chainString := string(chain)
writeLine(filterChains, existingFilterChains[chain])
writeBytesLine(filterChains, existingFilterChains[chain])
writeLine(filterRules, "-X", chainString)
}
}
@@ -663,16 +663,19 @@ func (proxier *Proxier) syncProxyRules() {
// Get iptables-save output so we can check for existing chains and rules.
// This will be a map of chain name to chain with rules as stored in iptables-save/iptables-restore
existingFilterChains := make(map[utiliptables.Chain]string)
proxier.iptablesData.Reset()
err := proxier.iptables.SaveInto(utiliptables.TableFilter, proxier.iptablesData)
existingFilterChains := make(map[utiliptables.Chain][]byte)
// TODO: Filter table is small so we're not reusing this buffer over rounds.
// However, to optimize it further, we should do that.
existingFilterChainsData := bytes.NewBuffer(nil)
err := proxier.iptables.SaveInto(utiliptables.TableFilter, existingFilterChainsData)
if err != nil { // if we failed to get any rules
glog.Errorf("Failed to execute iptables-save, syncing all rules: %v", err)
} else { // otherwise parse the output
existingFilterChains = utiliptables.GetChainLines(utiliptables.TableFilter, proxier.iptablesData.Bytes())
existingFilterChains = utiliptables.GetChainLines(utiliptables.TableFilter, existingFilterChainsData.Bytes())
}
existingNATChains := make(map[utiliptables.Chain]string)
// IMPORTANT: existingNATChains may share memory with proxier.iptablesData.
existingNATChains := make(map[utiliptables.Chain][]byte)
proxier.iptablesData.Reset()
err = proxier.iptables.SaveInto(utiliptables.TableNAT, proxier.iptablesData)
if err != nil { // if we failed to get any rules
@@ -696,14 +699,14 @@ func (proxier *Proxier) syncProxyRules() {
// (which most should have because we created them above).
for _, chainName := range []utiliptables.Chain{kubeServicesChain, kubeExternalServicesChain, kubeForwardChain} {
if chain, ok := existingFilterChains[chainName]; ok {
writeLine(proxier.filterChains, chain)
writeBytesLine(proxier.filterChains, chain)
} else {
writeLine(proxier.filterChains, utiliptables.MakeChainLine(chainName))
}
}
for _, chainName := range []utiliptables.Chain{kubeServicesChain, kubeNodePortsChain, kubePostroutingChain, KubeMarkMasqChain} {
if chain, ok := existingNATChains[chainName]; ok {
writeLine(proxier.natChains, chain)
writeBytesLine(proxier.natChains, chain)
} else {
writeLine(proxier.natChains, utiliptables.MakeChainLine(chainName))
}
@@ -763,7 +766,7 @@ func (proxier *Proxier) syncProxyRules() {
if hasEndpoints {
// Create the per-service chain, retaining counters if possible.
if chain, ok := existingNATChains[svcChain]; ok {
writeLine(proxier.natChains, chain)
writeBytesLine(proxier.natChains, chain)
} else {
writeLine(proxier.natChains, utiliptables.MakeChainLine(svcChain))
}
@@ -775,7 +778,7 @@ func (proxier *Proxier) syncProxyRules() {
// Only for services request OnlyLocal traffic
// create the per-service LB chain, retaining counters if possible.
if lbChain, ok := existingNATChains[svcXlbChain]; ok {
writeLine(proxier.natChains, lbChain)
writeBytesLine(proxier.natChains, lbChain)
} else {
writeLine(proxier.natChains, utiliptables.MakeChainLine(svcXlbChain))
}
@@ -891,7 +894,7 @@ func (proxier *Proxier) syncProxyRules() {
if ingress.IP != "" {
// create service firewall chain
if chain, ok := existingNATChains[fwChain]; ok {
writeLine(proxier.natChains, chain)
writeBytesLine(proxier.natChains, chain)
} else {
writeLine(proxier.natChains, utiliptables.MakeChainLine(fwChain))
}
@@ -1067,7 +1070,7 @@ func (proxier *Proxier) syncProxyRules() {
// Create the endpoint chain, retaining counters if possible.
if chain, ok := existingNATChains[utiliptables.Chain(endpointChain)]; ok {
writeLine(proxier.natChains, chain)
writeBytesLine(proxier.natChains, chain)
} else {
writeLine(proxier.natChains, utiliptables.MakeChainLine(endpointChain))
}
@@ -1215,7 +1218,7 @@ func (proxier *Proxier) syncProxyRules() {
// We must (as per iptables) write a chain-line for it, which has
// the nice effect of flushing the chain. Then we can remove the
// chain.
writeLine(proxier.natChains, existingNATChains[chain])
writeBytesLine(proxier.natChains, existingNATChains[chain])
writeLine(proxier.natRules, "-X", chainString)
}
}
@@ -1356,6 +1359,11 @@ func writeLine(buf *bytes.Buffer, words ...string) {
}
}
func writeBytesLine(buf *bytes.Buffer, bytes []byte) {
buf.Write(bytes)
buf.WriteByte('\n')
}
func openLocalPort(lp *utilproxy.LocalPort) (utilproxy.Closeable, error) {
// For ports on node IPs, open the actual port and hold it, even though we
// use iptables to redirect traffic.