add support for linux network namespace

config/parsing/service/parse.go

@@ -2,6 +2,7 @@ package service
 
 import (
 	"fmt"
+	"runtime"
 	"strings"
 	"time"
 
@@ -32,6 +33,7 @@ import (
 	"github.com/go-gost/x/registry"
 	xservice "github.com/go-gost/x/service"
 	"github.com/go-gost/x/stats"
+	"github.com/vishvananda/netns"
 )
 
 func ParseService(cfg *config.ServiceConfig) (service.Service, error) {
@@ -104,6 +106,7 @@ func ParseService(cfg *config.ServiceConfig) (service.Service, error) {
 	var ignoreChain bool
 	var pStats *stats.Stats
 	var observePeriod time.Duration
+	var netnsIn, netnsOut string
 	if cfg.Metadata != nil {
 		md := metadata.NewMetadata(cfg.Metadata)
 		ppv = mdutil.GetInt(md, parsing.MDKeyProxyProtocol)
@@ -125,6 +128,8 @@ func ParseService(cfg *config.ServiceConfig) (service.Service, error) {
 			pStats = &stats.Stats{}
 		}
 		observePeriod = mdutil.GetDuration(md, "observePeriod")
+		netnsIn = mdutil.GetString(md, "netns")
+		netnsOut = mdutil.GetString(md, "netns.out")
 	}
 
 	listenOpts := []listener.Option{
@@ -146,6 +151,27 @@ func ParseService(cfg *config.ServiceConfig) (service.Service, error) {
 		)
 	}
 
+	if netnsIn != "" {
+		runtime.LockOSThread()
+		defer runtime.UnlockOSThread()
+
+		originNs, err := netns.Get()
+		if err != nil {
+			return nil, fmt.Errorf("netns.Get(): %v", err)
+		}
+		defer netns.Set(originNs)
+
+		ns, err := netns.GetFromName(netnsIn)
+		if err != nil {
+			return nil, fmt.Errorf("netns.GetFromName(%s): %v", netnsIn, err)
+		}
+		defer ns.Close()
+
+		if err := netns.Set(ns); err != nil {
+			return nil, fmt.Errorf("netns.Set(%s): %v", netnsIn, err)
+		}
+	}
+
 	var ln listener.Listener
 	if rf := registry.ListenerRegistry().Get(cfg.Listener.Type); rf != nil {
 		ln = rf(listenOpts...)
@@ -209,6 +235,7 @@ func ParseService(cfg *config.ServiceConfig) (service.Service, error) {
 		chain.RetriesRouterOption(cfg.Handler.Retries),
 		// chain.TimeoutRouterOption(10*time.Second),
 		chain.InterfaceRouterOption(ifce),
+		chain.NetnsRouterOption(netnsOut),
 		chain.SockOptsRouterOption(sockOpts),
 		chain.ResolverRouterOption(registry.ResolverRegistry().Get(cfg.Resolver)),
 		chain.HostMapperRouterOption(registry.HostsRegistry().Get(cfg.Hosts)),