This commit is contained in:
Quentin McGaw
2026-07-16 21:09:07 +00:00
parent cd9ba54b37
commit 113253b523
5 changed files with 1097 additions and 1 deletions
+575
View File
@@ -3,9 +3,11 @@ package nftables
import (
"context"
"fmt"
"net/netip"
"github.com/google/nftables"
"github.com/google/nftables/expr"
"github.com/qdm12/gluetun/internal/models"
)
func (f *Firewall) AcceptIpv6MulticastOutput(_ context.Context, intf string) error {
@@ -76,3 +78,576 @@ func (f *Firewall) AcceptIpv6MulticastOutput(_ context.Context, intf string) err
return nil
}
func (f *Firewall) AcceptOutputTrafficToVPN(_ context.Context, defaultInterface string,
connection models.Connection, remove bool) error {
f.mutex.Lock()
defer f.mutex.Unlock()
conn, err := nftables.New()
if err != nil {
return fmt.Errorf("creating nftables connection: %w", err)
}
table, _, _, outputChain := setupFilterWithBaseChains(conn)
// Prepare the destination IP and port
const maxExprsLen = 7
exprs := make([]expr.Any, 0, maxExprsLen)
// Interface filter
if defaultInterface != "" && defaultInterface != "*" {
exprs = append(exprs,
&expr.Meta{Key: expr.MetaKeyOIFNAME, Register: 1},
&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte(defaultInterface + "\x00")},
)
}
// Destination IP address
if connection.IP.Is4() {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 16, // IPv4 destination address offset
Len: 4, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: connection.IP.AsSlice(),
},
)
} else { // IPv6
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 24, // IPv6 destination address offset
Len: 16, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: connection.IP.AsSlice(),
},
)
}
// Protocol (tcp or udp)
var protocolByte uint8
if connection.Protocol == "tcp" || connection.Protocol == "tcp-client" {
protocolByte = 6 // TCP
} else if connection.Protocol == "udp" {
protocolByte = 17 // UDP
} else {
return fmt.Errorf("unsupported protocol: %s", connection.Protocol)
}
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseTransportHeader,
Offset: 3, // Protocol byte offset in IP header
Len: 1,
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: []byte{protocolByte},
},
)
// Destination port
portBytes := []byte{byte(connection.Port >> 8), byte(connection.Port)} //nolint:mnd
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseTransportHeader,
Offset: 2, // destination port offset
Len: 2, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: portBytes,
},
&expr.Verdict{Kind: expr.VerdictAccept},
)
rule := &nftables.Rule{
Table: table,
Chain: outputChain,
Exprs: exprs,
}
if !remove {
conn.AddRule(rule)
f.rules = append(f.rules, rule)
} else {
err = f.deleteRule(conn, rule)
if err != nil {
return fmt.Errorf("deleting rule: %w", err)
}
}
err = conn.Flush()
if err != nil {
if !remove {
f.rules = f.rules[:len(f.rules)-1]
}
return fmt.Errorf("flushing: %w", err)
}
return nil
}
func (f *Firewall) AcceptOutput(_ context.Context, protocol, intf string, ip netip.Addr, port uint16, remove bool) error {
f.mutex.Lock()
defer f.mutex.Unlock()
conn, err := nftables.New()
if err != nil {
return fmt.Errorf("creating nftables connection: %w", err)
}
table, _, _, outputChain := setupFilterWithBaseChains(conn)
const maxExprsLen = 7
exprs := make([]expr.Any, 0, maxExprsLen)
if intf != "" && intf != "*" {
exprs = append(exprs,
&expr.Meta{Key: expr.MetaKeyOIFNAME, Register: 1},
&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte(intf + "\x00")},
)
}
if ip.Is4() {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 16, //nolint:mnd
Len: 4, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: ip.AsSlice(),
},
)
} else {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 24, //nolint:mnd
Len: 16, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: ip.AsSlice(),
},
)
}
var protocolByte uint8
switch protocol {
case "tcp":
protocolByte = 6 //nolint:mnd
case "udp":
protocolByte = 17 //nolint:mnd
default:
return fmt.Errorf("unsupported protocol: %s", protocol)
}
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseTransportHeader,
Offset: 3, //nolint:mnd
Len: 1,
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: []byte{protocolByte},
},
)
portBytes := []byte{byte(port >> 8), byte(port)} //nolint:mnd
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseTransportHeader,
Offset: 2, //nolint:mnd
Len: 2, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: portBytes,
},
&expr.Verdict{Kind: expr.VerdictAccept},
)
rule := &nftables.Rule{
Table: table,
Chain: outputChain,
Exprs: exprs,
}
if !remove {
conn.AddRule(rule)
f.rules = append(f.rules, rule)
} else {
err = f.deleteRule(conn, rule)
if err != nil {
return fmt.Errorf("deleting rule: %w", err)
}
}
err = conn.Flush()
if err != nil {
if !remove {
f.rules = f.rules[:len(f.rules)-1]
}
return fmt.Errorf("flushing: %w", err)
}
return nil
}
func (f *Firewall) AcceptOutputFromIPPortToIPPort(_ context.Context, protocol, intf string,
source, destination netip.AddrPort, remove bool,
) error {
f.mutex.Lock()
defer f.mutex.Unlock()
conn, err := nftables.New()
if err != nil {
return fmt.Errorf("creating nftables connection: %w", err)
}
table, _, _, outputChain := setupFilterWithBaseChains(conn)
const maxExprsLen = 10 //nolint:mnd
exprs := make([]expr.Any, 0, maxExprsLen)
if intf != "" && intf != "*" {
exprs = append(exprs,
&expr.Meta{Key: expr.MetaKeyOIFNAME, Register: 1},
&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte(intf + "\x00")},
)
}
if source.Addr().Is4() {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 12, //nolint:mnd
Len: 4, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: source.Addr().AsSlice(),
},
)
} else {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 8, //nolint:mnd
Len: 16, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: source.Addr().AsSlice(),
},
)
}
if destination.Addr().Is4() {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 16, //nolint:mnd
Len: 4, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: destination.Addr().AsSlice(),
},
)
} else {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 24, //nolint:mnd
Len: 16, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: destination.Addr().AsSlice(),
},
)
}
var protocolByte uint8
switch protocol {
case "tcp":
protocolByte = 6 //nolint:mnd
case "udp":
protocolByte = 17 //nolint:mnd
default:
return fmt.Errorf("unsupported protocol: %s", protocol)
}
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseTransportHeader,
Offset: 3, //nolint:mnd
Len: 1,
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: []byte{protocolByte},
},
)
sourcePortBytes := []byte{byte(source.Port() >> 8), byte(source.Port())} //nolint:mnd
destinationPortBytes := []byte{byte(destination.Port() >> 8), byte(destination.Port())} //nolint:mnd
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseTransportHeader,
Offset: 0, //nolint:mnd
Len: 2, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: sourcePortBytes,
},
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseTransportHeader,
Offset: 2, //nolint:mnd
Len: 2, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: destinationPortBytes,
},
&expr.Verdict{Kind: expr.VerdictAccept},
)
rule := &nftables.Rule{
Table: table,
Chain: outputChain,
Exprs: exprs,
}
if !remove {
conn.AddRule(rule)
f.rules = append(f.rules, rule)
} else {
err = f.deleteRule(conn, rule)
if err != nil {
return fmt.Errorf("deleting rule: %w", err)
}
}
err = conn.Flush()
if err != nil {
if !remove {
f.rules = f.rules[:len(f.rules)-1]
}
return fmt.Errorf("flushing: %w", err)
}
return nil
}
func (f *Firewall) AcceptOutputFromIPToSubnet(_ context.Context, intf string, assignedIP netip.Addr,
subnet netip.Prefix, remove bool,
) error {
f.mutex.Lock()
defer f.mutex.Unlock()
conn, err := nftables.New()
if err != nil {
return fmt.Errorf("creating nftables connection: %w", err)
}
table, _, _, outputChain := setupFilterWithBaseChains(conn)
const maxExprsLen = 8
exprs := make([]expr.Any, 0, maxExprsLen)
if intf != "" && intf != "*" {
exprs = append(exprs,
&expr.Meta{Key: expr.MetaKeyOIFNAME, Register: 1},
&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte(intf + "\x00")},
)
}
if assignedIP.Is4() {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 12, //nolint:mnd
Len: 4, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: assignedIP.AsSlice(),
},
)
} else {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 8, //nolint:mnd
Len: 16, //nolint:mnd
},
&expr.Cmp{
Op: expr.CmpOpEq,
Register: 1,
Data: assignedIP.AsSlice(),
},
)
}
if subnet.Addr().Is4() {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 16, //nolint:mnd
Len: 4, //nolint:mnd
},
&expr.Bitwise{
SourceRegister: 1,
DestRegister: 1,
Len: 4, //nolint:mnd
Mask: subnet.Masked().Addr().AsSlice(),
Xor: []byte{0, 0, 0, 0}, //nolint:mnd
},
)
} else {
exprs = append(exprs,
&expr.Payload{
DestRegister: 1,
Base: expr.PayloadBaseNetworkHeader,
Offset: 24, //nolint:mnd
Len: 16, //nolint:mnd
},
&expr.Bitwise{
SourceRegister: 1,
DestRegister: 1,
Len: 16, //nolint:mnd
Mask: subnet.Masked().Addr().AsSlice(),
Xor: []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, //nolint:mnd
},
)
}
exprs = append(exprs,
&expr.Verdict{Kind: expr.VerdictAccept},
)
rule := &nftables.Rule{
Table: table,
Chain: outputChain,
Exprs: exprs,
}
if !remove {
conn.AddRule(rule)
f.rules = append(f.rules, rule)
} else {
err = f.deleteRule(conn, rule)
if err != nil {
return fmt.Errorf("deleting rule: %w", err)
}
}
err = conn.Flush()
if err != nil {
if !remove {
f.rules = f.rules[:len(f.rules)-1]
}
return fmt.Errorf("flushing: %w", err)
}
return nil
}
func (f *Firewall) AcceptOutputThroughInterface(_ context.Context, intf string, remove bool) error {
f.mutex.Lock()
defer f.mutex.Unlock()
conn, err := nftables.New()
if err != nil {
return fmt.Errorf("creating nftables connection: %w", err)
}
table, _, _, outputChain := setupFilterWithBaseChains(conn)
const maxExprsLen = 3
exprs := make([]expr.Any, 0, maxExprsLen)
if intf != "" && intf != "*" {
exprs = append(exprs,
&expr.Meta{Key: expr.MetaKeyOIFNAME, Register: 1},
&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte(intf + "\x00")},
)
}
exprs = append(exprs,
&expr.Verdict{Kind: expr.VerdictAccept},
)
rule := &nftables.Rule{
Table: table,
Chain: outputChain,
Exprs: exprs,
}
if !remove {
conn.AddRule(rule)
f.rules = append(f.rules, rule)
} else {
err = f.deleteRule(conn, rule)
if err != nil {
return fmt.Errorf("deleting rule: %w", err)
}
}
err = conn.Flush()
if err != nil {
if !remove {
f.rules = f.rules[:len(f.rules)-1]
}
return fmt.Errorf("flushing: %w", err)
}
return nil
}