netbird/client/firewall/create_linux.go
Zoltan Papp 006ba32086
Fix/acl for forward (#1305)
Fix ACL on routed traffic and code refactor
2023-12-08 10:48:21 +01:00

108 lines
2.8 KiB
Go

//go:build !android
package firewall
import (
"context"
"fmt"
"os"
"github.com/coreos/go-iptables/iptables"
"github.com/google/nftables"
log "github.com/sirupsen/logrus"
nbiptables "github.com/netbirdio/netbird/client/firewall/iptables"
firewall "github.com/netbirdio/netbird/client/firewall/manager"
nbnftables "github.com/netbirdio/netbird/client/firewall/nftables"
"github.com/netbirdio/netbird/client/firewall/uspfilter"
)
const (
// UNKNOWN is the default value for the firewall type for unknown firewall type
UNKNOWN FWType = iota
// IPTABLES is the value for the iptables firewall type
IPTABLES
// NFTABLES is the value for the nftables firewall type
NFTABLES
)
// SKIP_NFTABLES_ENV is the environment variable to skip nftables check
const SKIP_NFTABLES_ENV = "NB_SKIP_NFTABLES_CHECK"
// FWType is the type for the firewall type
type FWType int
func NewFirewall(context context.Context, iface IFaceMapper) (firewall.Manager, error) {
// on the linux system we try to user nftables or iptables
// in any case, because we need to allow netbird interface traffic
// so we use AllowNetbird traffic from these firewall managers
// for the userspace packet filtering firewall
var fm firewall.Manager
var errFw error
switch check() {
case IPTABLES:
log.Debug("creating an iptables firewall manager")
fm, errFw = nbiptables.Create(context, iface)
if errFw != nil {
log.Errorf("failed to create iptables manager: %s", errFw)
}
case NFTABLES:
log.Debug("creating an nftables firewall manager")
fm, errFw = nbnftables.Create(context, iface)
if errFw != nil {
log.Errorf("failed to create nftables manager: %s", errFw)
}
default:
errFw = fmt.Errorf("no firewall manager found")
log.Debug("no firewall manager found, try to use userspace packet filtering firewall")
}
if iface.IsUserspaceBind() {
var errUsp error
if errFw == nil {
fm, errUsp = uspfilter.CreateWithNativeFirewall(iface, fm)
} else {
fm, errUsp = uspfilter.Create(iface)
}
if errUsp != nil {
log.Debugf("failed to create userspace filtering firewall: %s", errUsp)
return nil, errUsp
}
if err := fm.AllowNetbird(); err != nil {
log.Errorf("failed to allow netbird interface traffic: %v", err)
}
return fm, nil
}
if errFw != nil {
return nil, errFw
}
return fm, nil
}
// check returns the firewall type based on common lib checks. It returns UNKNOWN if no firewall is found.
func check() FWType {
nf := nftables.Conn{}
if _, err := nf.ListChains(); err == nil && os.Getenv(SKIP_NFTABLES_ENV) != "true" {
return NFTABLES
}
ip, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
if err != nil {
return UNKNOWN
}
if isIptablesClientAvailable(ip) {
return IPTABLES
}
return UNKNOWN
}
func isIptablesClientAvailable(client *iptables.IPTables) bool {
_, err := client.ListChains("filter")
return err == nil
}