rewrite by golib

Author: CMGS

node/bridge.go

@@ -3,6 +3,7 @@ package node
 import (
 	"context"
 	"fmt"
+	"net"
 	"os/exec"
 	"strings"
 
@@ -11,31 +12,29 @@ import (
 
 const cni0Bridge = "cni0"
 
-// setupBridge creates the cni0 bridge and assigns the gateway IP.
 func setupBridge(ctx context.Context, gatewayIP, subnetCIDR string) error {
 	logger := log.WithFunc("node.setupBridge")
 
-	// Create bridge if it does not exist.
 	addCmd := exec.CommandContext(ctx, "ip", "link", "add", cni0Bridge, "type", "bridge")
 	out, err := addCmd.CombinedOutput()
 	if err != nil && !strings.Contains(string(out), "File exists") {
 		return fmt.Errorf("create bridge %s: %w: %s", cni0Bridge, err, out)
 	}
 
-	// Assign gateway address (idempotent via replace).
-	_, mask, err := parseCIDR(subnetCIDR)
+	_, ipNet, err := net.ParseCIDR(subnetCIDR)
 	if err != nil {
 		return fmt.Errorf("parse subnet cidr: %w", err)
 	}
-	cidr := fmt.Sprintf("%s/%s", gatewayIP, mask)
+	ones, _ := ipNet.Mask.Size()
+	cidr := fmt.Sprintf("%s/%d", gatewayIP, ones)
+
 	//nolint:gosec // ip args from trusted config
 	addrCmd := exec.CommandContext(ctx, "ip", "addr", "replace", cidr, "dev", cni0Bridge)
 	out, err = addrCmd.CombinedOutput()
 	if err != nil {
 		return fmt.Errorf("assign %s to %s: %w: %s", cidr, cni0Bridge, err, out)
 	}
 
-	// Bring up the bridge.
 	upCmd := exec.CommandContext(ctx, "ip", "link", "set", cni0Bridge, "up")
 	out, err = upCmd.CombinedOutput()
 	if err != nil {
@@ -45,12 +44,3 @@ func setupBridge(ctx context.Context, gatewayIP, subnetCIDR string) error {
 	logger.Infof(ctx, "bridge %s configured with gateway %s", cni0Bridge, cidr)
 	return nil
 }
-
-// parseCIDR extracts the mask prefix from a CIDR string (e.g. "24" from "172.20.100.0/24").
-func parseCIDR(cidr string) (network, mask string, err error) {
-	parts := strings.SplitN(cidr, "/", 2)
-	if len(parts) != 2 {
-		return "", "", fmt.Errorf("invalid cidr: %s", cidr)
-	}
-	return parts[0], parts[1], nil
-}

node/sysctl.go

@@ -3,12 +3,15 @@ package node
 import (
 	"context"
 	"fmt"
-	"os/exec"
+	"os"
+	"path/filepath"
+	"strings"
 
 	"github.com/projecteru2/core/log"
 )
 
-// setupSysctl applies kernel parameters required for VPC-native VM networking.
+const procSysBase = "/proc/sys"
+
 func setupSysctl(ctx context.Context, primaryNIC string, secondaryNICs []string) error {
 	logger := log.WithFunc("node.setupSysctl")
 
@@ -26,12 +29,9 @@ func setupSysctl(ctx context.Context, primaryNIC string, secondaryNICs []string)
 	}
 
 	for key, val := range settings {
-		param := fmt.Sprintf("%s=%s", key, val)
-		//nolint:gosec // sysctl args from trusted config
-		cmd := exec.CommandContext(ctx, "sysctl", "-w", param)
-		out, err := cmd.CombinedOutput()
-		if err != nil {
-			return fmt.Errorf("sysctl %s: %w: %s", param, err, out)
+		path := filepath.Join(procSysBase, strings.ReplaceAll(key, ".", "/"))
+		if err := os.WriteFile(path, []byte(val), 0o644); err != nil { //nolint:gosec // sysctl tuning
+			return fmt.Errorf("write sysctl %s=%s: %w", key, val, err)
 		}
 	}
 	logger.Info(ctx, "sysctl parameters applied")