Added some ctl boilerplate

clitools/pkg/node/network.go

@@ -0,0 +1,91 @@
+package node
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"strings"
+
+	system "undecided.project/monok8s/pkg/system"
+	"k8s.io/klog/v2"
+)
+
+type NetworkConfig struct {
+	MgmtIface   string
+	MgmtAddress string
+	MgmtGateway string
+}
+
+func ConfigureMgmtInterface(cfg NetworkConfig) Step {
+	return func(ctx context.Context, nctx *NodeContext) error {
+		if strings.TrimSpace(cfg.MgmtIface) == "" {
+			return fmt.Errorf("mgmt interface is required")
+		}
+		if strings.TrimSpace(cfg.MgmtAddress) == "" {
+			return fmt.Errorf("mgmt address is required")
+		}
+		ip, ipNet, err := net.ParseCIDR(cfg.MgmtAddress)
+		if err != nil {
+			return fmt.Errorf("invalid mgmt address %q: %w", cfg.MgmtAddress, err)
+		}
+		wantIP := ip.String()
+		if gw := strings.TrimSpace(cfg.MgmtGateway); gw != "" && net.ParseIP(gw) == nil {
+			return fmt.Errorf("invalid mgmt gateway %q", gw)
+		}
+
+		if _, err := nctx.System.Run(ctx, "ip", "link", "show", "dev", cfg.MgmtIface); err != nil {
+			return fmt.Errorf("interface not found: %s: %w", cfg.MgmtIface, err)
+		}
+		if _, err := nctx.System.Run(ctx, "ip", "link", "set", "dev", cfg.MgmtIface, "up"); err != nil {
+			return fmt.Errorf("failed to bring up interface %s: %w", cfg.MgmtIface, err)
+		}
+
+		hasAddr, err := interfaceHasIPv4(ctx, nctx, cfg.MgmtIface, wantIP)
+		if err != nil {
+			return fmt.Errorf("failed checking existing address on %s: %w", cfg.MgmtIface, err)
+		}
+		if hasAddr {
+			klog.Infof("address already present on %s: %s", cfg.MgmtIface, cfg.MgmtAddress)
+		} else {
+			if _, err := nctx.System.Run(ctx, "ip", "addr", "add", ipNet.String(), "dev", cfg.MgmtIface); err != nil {
+				return fmt.Errorf("failed assigning %s to %s: %w", ipNet.String(), cfg.MgmtIface, err)
+			}
+		}
+
+		if gw := strings.TrimSpace(cfg.MgmtGateway); gw != "" {
+			if _, err := nctx.System.Run(ctx, "ip", "route", "replace", "default", "via", gw, "dev", cfg.MgmtIface); err != nil {
+				return fmt.Errorf("failed setting default route via %s dev %s: %w", gw, cfg.MgmtIface, err)
+			}
+		}
+		return nil
+	}
+}
+
+func EnsureIPForward(ctx context.Context, n *NodeContext) error {
+	return system.EnsureSysctl(ctx, n.System, "net.ipv4.ip_forward", "1")
+}
+
+func ConfigureDNS(context.Context, *NodeContext) error {
+	klog.Info("configure_dns: TODO implement resolv.conf rendering")
+	return nil
+}
+
+func interfaceHasIPv4(ctx context.Context, nctx *NodeContext, iface, wantIP string) (bool, error) {
+	res, err := nctx.System.Run(ctx, "ip", "-o", "-4", "addr", "show", "dev", iface)
+	if err != nil {
+		return false, err
+	}
+	for _, line := range strings.Split(res.Stdout, "\n") {
+		fields := strings.Fields(strings.TrimSpace(line))
+		for i := 0; i < len(fields)-1; i++ {
+			if fields[i] != "inet" {
+				continue
+			}
+			ip, _, err := net.ParseCIDR(fields[i+1])
+			if err == nil && ip.String() == wantIP {
+				return true, nil
+			}
+		}
+	}
+	return false, nil
+}