func init()

in pkg/config/config_policy_routing.go [76:218]
141 lines of code
3 McCabe index (conditional complexity)

func init() {
	f := func(ip net.IP) (linkIndex int, netdev string, gw net.IP) {
		routes, err := netlink.RouteGet(ip)
		if err != nil {
			glog.Errorf("failed to get route for IP: %v (%v)", ip, err)
			return
		}
		gw = routes[0].Gw
		linkIndex = routes[0].LinkIndex

		l, err := netlink.LinkByIndex(linkIndex)
		if err != nil {
			glog.Errorf("failed to get the link by index: %v (%v)", linkIndex, err)
		}
		netdev = l.Attrs().Name
		return
	}
	defaultLinkIndex, defaultNetdev, defaultGateway = f(net.IPv4(8, 8, 8, 8))
	_, localNetdev, _ = f(net.IPv4(127, 0, 0, 1))

	sysctlReversePathFilter := fmt.Sprintf("net.ipv4.conf.%s.rp_filter", defaultNetdev)
	hairpinMaskStr := fmt.Sprintf("0x%x", hairpinMask)
	PolicyRoutingConfigSet.Configs = []Config{
		SysctlConfig{
			Key:          sysctlReversePathFilter,
			Value:        "2",
			DefaultValue: "1",
			SysctlFunc:   sysctl.Sysctl,
		},
		IPTablesRuleConfig{
			IPTablesChainSpec{
				TableName:      tableMangle,
				ChainName:      gcpPreRoutingChain,
				IsDefaultChain: false,
				IPT:            ipt,
			},
			[]IPTablesRuleSpec{
				[]string{
					"-j", "CONNMARK", "--restore-mark", "--nfmask", hairpinMaskStr, "--ctmask", hairpinMaskStr,
					"-m", "comment", "--comment", policyRoutingGcpPreRoutingComment,
				},
			},
			ipt,
		},
		IPTablesRuleConfig{
			IPTablesChainSpec{
				TableName:      tableMangle,
				ChainName:      preRoutingChain,
				IsDefaultChain: true,
				IPT:            ipt,
			},
			[]IPTablesRuleSpec{
				[]string{"-j", gcpPreRoutingChain, "-m", "comment", "--comment", policyRoutingPreRoutingComment},
			},
			ipt,
		},
		IPTablesRuleConfig{
			IPTablesChainSpec{
				TableName:      tableMangle,
				ChainName:      gcpPostRoutingChain,
				IsDefaultChain: false,
				IPT:            ipt,
			},
			[]IPTablesRuleSpec{
				[]string{"-m", "mark", "--mark",
					fmt.Sprintf("0x%x/0x%x", hairpinMark, hairpinMask),
					"-j", "CONNMARK", "--save-mark", "--nfmask", hairpinMaskStr, "--ctmask", hairpinMaskStr, "-m",
					"comment", "--comment", policyRoutingGcpPostRoutingComment},
			},
			ipt,
		},
		IPTablesRuleConfig{
			IPTablesChainSpec{
				TableName:      tableMangle,
				ChainName:      postRoutingChain,
				IsDefaultChain: true,
				IPT:            ipt,
			},
			[]IPTablesRuleSpec{
				[]string{"-j", gcpPostRoutingChain, "-m", "comment", "--comment", policyRoutingPostRoutingComment},
			},
			ipt,
		},
		IPRouteConfig{
			Route: netlink.Route{
				Table:     customRouteTable,
				LinkIndex: defaultLinkIndex,
				Gw:        defaultGateway,
				Dst:       nil,
			},
			RouteAdd: netlink.RouteAdd,
			RouteDel: netlink.RouteDel,
		},
		IPRuleConfig{
			Rule: netlink.Rule{
				Mark:              hairpinMark,
				Mask:              hairpinMask,
				Table:             unix.RT_TABLE_MAIN,
				Priority:          hairpinRulePriority,
				SuppressIfgroup:   -1,
				SuppressPrefixlen: -1,
				Goto:              -1,
				Flow:              -1,
			},
			RuleAdd:  netlink.RuleAdd,
			RuleDel:  netlink.RuleDel,
			RuleList: netlink.RuleList,
		},
		IPRuleConfig{
			Rule: netlink.Rule{
				IifName:           localNetdev,
				Table:             unix.RT_TABLE_MAIN,
				Priority:          localRulePriority,
				SuppressIfgroup:   -1,
				SuppressPrefixlen: -1,
				Mark:              -1,
				Mask:              -1,
				Goto:              -1,
				Flow:              -1,
			},
			RuleAdd:  netlink.RuleAdd,
			RuleDel:  netlink.RuleDel,
			RuleList: netlink.RuleList,
		},
		IPRuleConfig{
			Rule: netlink.Rule{
				IifName:           defaultNetdev,
				Invert:            true,
				Table:             customRouteTable,
				Priority:          policyRoutingRulePriority,
				SuppressIfgroup:   -1,
				SuppressPrefixlen: -1,
				Mark:              -1,
				Mask:              -1,
				Goto:              -1,
				Flow:              -1,
			},
			RuleAdd:  netlink.RuleAdd,
			RuleDel:  netlink.RuleDel,
			RuleList: netlink.RuleList,
		},
	}
}