func()

in cmd/ip-masq-agent-v2/ip-masq-agent.go [359:400]

• 31 lines of code
• 8 McCabe index (conditional complexity)

func (m *MasqDaemon) syncMasqRulesIPv6() error {
	isIPv6Enabled := *enableIPv6

	if isIPv6Enabled {
		// make sure our custom chain for ipv6 non-masquerade exists
		_, err := m.ip6tables.EnsureChain(utiliptables.TableNAT, masqChain)
		if err != nil {
			return err
		}
		// ensure that any non-local in POSTROUTING jumps to masqChain
		err = m.ensurePostroutingJumpIPv6()
		if err != nil {
			return err
		}
		// build up lines to pass to ip6tables-restore
		lines6 := bytes.NewBuffer(nil)
		writeLine(lines6, "*nat")
		writeLine(lines6, utiliptables.MakeChainLine(masqChain)) // effectively flushes masqChain atomically with rule restore

		// link-local IPv6 CIDR is non-masquerade by default
		if !m.config.MasqLinkLocalIPv6 {
			writeNonMasqRule(lines6, linkLocalCIDRIPv6)
		}

		for _, cidr := range m.config.NonMasqueradeCIDRs {
			if isIPv6CIDR(cidr) {
				writeNonMasqRule(lines6, cidr)
			}
		}

		// masquerade all other traffic that is not bound for a --dst-type LOCAL destination
		writeMasqRule(lines6)

		writeLine(lines6, "COMMIT")

		err = m.ip6tables.RestoreAll(lines6.Bytes(), utiliptables.NoFlushTables, utiliptables.NoRestoreCounters)
		if err != nil {
			return err
		}
	}
	return nil
}