netbird/util/net/env_linux.go

120 lines
2.8 KiB
Go

//go:build linux && !android
package net
import (
"errors"
"os"
"strconv"
"syscall"
"time"
log "github.com/sirupsen/logrus"
"github.com/vishvananda/netlink"
"github.com/netbirdio/netbird/client/iface/netstack"
)
const (
// these have the same effect, skip socket env supported for backward compatibility
envSkipSocketMark = "NB_SKIP_SOCKET_MARK"
envUseLegacyRouting = "NB_USE_LEGACY_ROUTING"
)
var advancedRoutingSupported bool
func Init() {
advancedRoutingSupported = checkAdvancedRoutingSupport()
}
func AdvancedRouting() bool {
return advancedRoutingSupported
}
func checkAdvancedRoutingSupport() bool {
var err error
var legacyRouting bool
if val := os.Getenv(envUseLegacyRouting); val != "" {
legacyRouting, err = strconv.ParseBool(val)
if err != nil {
log.Warnf("failed to parse %s: %v", envUseLegacyRouting, err)
}
}
var skipSocketMark bool
if val := os.Getenv(envSkipSocketMark); val != "" {
skipSocketMark, err = strconv.ParseBool(val)
if err != nil {
log.Warnf("failed to parse %s: %v", envSkipSocketMark, err)
}
}
// requested to disable advanced routing
if legacyRouting || skipSocketMark ||
// envCustomRoutingDisabled disables the custom dialers.
// There is no point in using advanced routing without those, as they set up fwmarks on the sockets.
CustomRoutingDisabled() ||
// netstack mode doesn't need routing at all
netstack.IsEnabled() {
log.Info("advanced routing has been requested to be disabled")
return false
}
if !CheckFwmarkSupport() || !CheckRuleOperationsSupport() {
log.Warn("system doesn't support required routing features, falling back to legacy routing")
return false
}
log.Info("system supports advanced routing")
return true
}
func CheckFwmarkSupport() bool {
// temporarily enable advanced routing to check fwmarks are supported
old := advancedRoutingSupported
advancedRoutingSupported = true
defer func() {
advancedRoutingSupported = old
}()
dialer := NewDialer()
dialer.Timeout = 100 * time.Millisecond
conn, err := dialer.Dial("udp", "127.0.0.1:9")
if err != nil {
log.Warnf("failed to dial with fwmark: %v", err)
return false
}
if err := conn.Close(); err != nil {
log.Warnf("failed to close connection: %v", err)
}
return true
}
func CheckRuleOperationsSupport() bool {
rule := netlink.NewRule()
// low precedence, semi-random
rule.Priority = 32321
rule.Table = syscall.RT_TABLE_MAIN
rule.Family = netlink.FAMILY_V4
if err := netlink.RuleAdd(rule); err != nil {
if errors.Is(err, syscall.EOPNOTSUPP) {
log.Warn("IP rule operations are not supported")
return false
}
log.Warnf("failed to test rule support: %v", err)
return false
}
if err := netlink.RuleDel(rule); err != nil {
log.Warnf("failed to delete test rule: %v", err)
}
return true
}