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ipset_linux.go
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ipset_linux.go
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// Apache License 2.0
// @mdlayher https://github.com/mdlayher/netlink
// Ref: https://github.com/vishvananda/netlink/blob/master/nl/nl_linux.go
package main
import (
"bytes"
"encoding/binary"
"net"
"strings"
"sync"
"sync/atomic"
"syscall"
"unsafe"
"github.com/nadoo/glider/common/log"
)
// NFNL_SUBSYS_IPSET netfilter netlink message types
// https://github.com/torvalds/linux/blob/9e66317d3c92ddaab330c125dfe9d06eee268aff/include/uapi/linux/netfilter/nfnetlink.h#L56
const NFNL_SUBSYS_IPSET = 6
// IPSET_PROTOCOL The protocol version
// http://git.netfilter.org/ipset/tree/include/libipset/linux_ip_set.h
const IPSET_PROTOCOL = 6
// IPSET_MAXNAMELEN The max length of strings including NUL: set and type identifiers
const IPSET_MAXNAMELEN = 32
// Message types and commands
const (
IPSET_CMD_CREATE = 2
IPSET_CMD_FLUSH = 4
IPSET_CMD_ADD = 9
IPSET_CMD_DEL = 10
)
// Attributes at command level
const (
IPSET_ATTR_PROTOCOL = 1 /* 1: Protocol version */
IPSET_ATTR_SETNAME = 2 /* 2: Name of the set */
IPSET_ATTR_TYPENAME = 3 /* 3: Typename */
IPSET_ATTR_REVISION = 4 /* 4: Settype revision */
IPSET_ATTR_FAMILY = 5 /* 5: Settype family */
IPSET_ATTR_DATA = 7 /* 7: Nested attributes */
)
// CADT specific attributes
const (
IPSET_ATTR_IP = 1
IPSET_ATTR_CIDR = 3
)
// IP specific attributes
const (
IPSET_ATTR_IPADDR_IPV4 = 1
IPSET_ATTR_IPADDR_IPV6 = 2
)
// ATTR flags
const (
NLA_F_NESTED = (1 << 15)
NLA_F_NET_BYTEORDER = (1 << 14)
)
var nextSeqNr uint32
var nativeEndian binary.ByteOrder
// IPSetManager struct
type IPSetManager struct {
fd int
lsa syscall.SockaddrNetlink
mainSet string
domainSet sync.Map
}
// NewIPSetManager returns a IPSetManager
func NewIPSetManager(mainSet string, rules []*RuleConf) (*IPSetManager, error) {
fd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW, syscall.NETLINK_NETFILTER)
if err != nil {
log.F("%s", err)
return nil, err
}
// defer syscall.Close(fd)
lsa := syscall.SockaddrNetlink{
Family: syscall.AF_NETLINK,
}
if err = syscall.Bind(fd, &lsa); err != nil {
log.F("%s", err)
return nil, err
}
m := &IPSetManager{fd: fd, lsa: lsa, mainSet: mainSet}
CreateSet(fd, lsa, mainSet)
for _, r := range rules {
set := r.IPSet
if set != "" && set != m.mainSet {
CreateSet(fd, lsa, set)
} else {
set = m.mainSet
}
for _, domain := range r.Domain {
m.domainSet.Store(domain, set)
}
for _, ip := range r.IP {
AddToSet(fd, lsa, mainSet, ip)
AddToSet(fd, lsa, r.IPSet, ip)
}
for _, cidr := range r.CIDR {
AddToSet(fd, lsa, mainSet, cidr)
AddToSet(fd, lsa, r.IPSet, cidr)
}
}
return m, nil
}
// AddDomainIP implements the DNSAnswerHandler function, used to update ipset according to domainSet rule
func (m *IPSetManager) AddDomainIP(domain, ip string) error {
if ip != "" {
domainParts := strings.Split(domain, ".")
length := len(domainParts)
for i := length - 2; i >= 0; i-- {
domain := strings.Join(domainParts[i:length], ".")
// find in domainMap
if ipset, ok := m.domainSet.Load(domain); ok {
AddToSet(m.fd, m.lsa, m.mainSet, ip)
if ipset.(string) != m.mainSet {
AddToSet(m.fd, m.lsa, ipset.(string), ip)
}
}
}
}
return nil
}
// CreateSet create a ipset
func CreateSet(fd int, lsa syscall.SockaddrNetlink, setName string) {
if setName == "" {
return
}
if len(setName) > IPSET_MAXNAMELEN {
log.Fatal("ipset: name too long")
}
log.F("ipset create %s hash:net", setName)
req := NewNetlinkRequest(IPSET_CMD_CREATE|(NFNL_SUBSYS_IPSET<<8), syscall.NLM_F_REQUEST)
// TODO: support AF_INET6
req.AddData(NewNfGenMsg(syscall.AF_INET, 0, 0))
req.AddData(NewRtAttr(IPSET_ATTR_PROTOCOL, Uint8Attr(IPSET_PROTOCOL)))
req.AddData(NewRtAttr(IPSET_ATTR_SETNAME, ZeroTerminated(setName)))
req.AddData(NewRtAttr(IPSET_ATTR_TYPENAME, ZeroTerminated("hash:net")))
req.AddData(NewRtAttr(IPSET_ATTR_REVISION, Uint8Attr(1)))
req.AddData(NewRtAttr(IPSET_ATTR_FAMILY, Uint8Attr(2)))
req.AddData(NewRtAttr(IPSET_ATTR_DATA|NLA_F_NESTED, nil))
err := syscall.Sendto(fd, req.Serialize(), 0, &lsa)
if err != nil {
log.F("%s", err)
}
FlushSet(fd, lsa, setName)
}
// FlushSet flush a ipset
func FlushSet(fd int, lsa syscall.SockaddrNetlink, setName string) {
log.F("ipset flush %s", setName)
req := NewNetlinkRequest(IPSET_CMD_FLUSH|(NFNL_SUBSYS_IPSET<<8), syscall.NLM_F_REQUEST)
// TODO: support AF_INET6
req.AddData(NewNfGenMsg(syscall.AF_INET, 0, 0))
req.AddData(NewRtAttr(IPSET_ATTR_PROTOCOL, Uint8Attr(IPSET_PROTOCOL)))
req.AddData(NewRtAttr(IPSET_ATTR_SETNAME, ZeroTerminated(setName)))
err := syscall.Sendto(fd, req.Serialize(), 0, &lsa)
if err != nil {
log.F("%s", err)
}
}
// AddToSet adds an entry to ipset
func AddToSet(fd int, lsa syscall.SockaddrNetlink, setName, entry string) {
if setName == "" {
return
}
if len(setName) > IPSET_MAXNAMELEN {
log.F("ipset: name too long")
}
log.F("ipset add %s %s", setName, entry)
var ip net.IP
var cidr *net.IPNet
ip, cidr, err := net.ParseCIDR(entry)
if err != nil {
ip = net.ParseIP(entry)
}
if ip == nil {
log.F("ipset: parse %s error", entry)
return
}
req := NewNetlinkRequest(IPSET_CMD_ADD|(NFNL_SUBSYS_IPSET<<8), syscall.NLM_F_REQUEST)
// TODO: support AF_INET6
req.AddData(NewNfGenMsg(syscall.AF_INET, 0, 0))
req.AddData(NewRtAttr(IPSET_ATTR_PROTOCOL, Uint8Attr(IPSET_PROTOCOL)))
req.AddData(NewRtAttr(IPSET_ATTR_SETNAME, ZeroTerminated(setName)))
attrNested := NewRtAttr(IPSET_ATTR_DATA|NLA_F_NESTED, nil)
attrIP := NewRtAttrChild(attrNested, IPSET_ATTR_IP|NLA_F_NESTED, nil)
// TODO: support ipV6
NewRtAttrChild(attrIP, IPSET_ATTR_IPADDR_IPV4|NLA_F_NET_BYTEORDER, ip.To4())
// for cidr prefix
if cidr != nil {
cidrPrefix, _ := cidr.Mask.Size()
NewRtAttrChild(attrNested, IPSET_ATTR_CIDR, Uint8Attr(uint8(cidrPrefix)))
}
NewRtAttrChild(attrNested, 9|NLA_F_NET_BYTEORDER, Uint32Attr(0))
req.AddData(attrNested)
err = syscall.Sendto(fd, req.Serialize(), 0, &lsa)
if err != nil {
log.F("%s", err)
}
}
// NativeEndian get native endianness for the system
func NativeEndian() binary.ByteOrder {
if nativeEndian == nil {
var x uint32 = 0x01020304
if *(*byte)(unsafe.Pointer(&x)) == 0x01 {
nativeEndian = binary.BigEndian
} else {
nativeEndian = binary.LittleEndian
}
}
return nativeEndian
}
func rtaAlignOf(attrlen int) int {
return (attrlen + syscall.RTA_ALIGNTO - 1) & ^(syscall.RTA_ALIGNTO - 1)
}
// NetlinkRequestData .
type NetlinkRequestData interface {
Len() int
Serialize() []byte
}
// NfGenMsg .
type NfGenMsg struct {
nfgenFamily uint8
version uint8
resID uint16
}
// NewNfGenMsg .
func NewNfGenMsg(nfgenFamily, version, resID int) *NfGenMsg {
return &NfGenMsg{
nfgenFamily: uint8(nfgenFamily),
version: uint8(version),
resID: uint16(resID),
}
}
// Len .
func (m *NfGenMsg) Len() int {
return rtaAlignOf(4)
}
// Serialize .
func (m *NfGenMsg) Serialize() []byte {
native := NativeEndian()
length := m.Len()
buf := make([]byte, rtaAlignOf(length))
buf[0] = m.nfgenFamily
buf[1] = m.version
native.PutUint16(buf[2:4], m.resID)
return buf
}
// RtAttr Extend RtAttr to handle data and children
type RtAttr struct {
syscall.RtAttr
Data []byte
children []NetlinkRequestData
}
// NewRtAttr Create a new Extended RtAttr object
func NewRtAttr(attrType int, data []byte) *RtAttr {
return &RtAttr{
RtAttr: syscall.RtAttr{
Type: uint16(attrType),
},
children: []NetlinkRequestData{},
Data: data,
}
}
// NewRtAttrChild Create a new RtAttr obj anc add it as a child of an existing object
func NewRtAttrChild(parent *RtAttr, attrType int, data []byte) *RtAttr {
attr := NewRtAttr(attrType, data)
parent.children = append(parent.children, attr)
return attr
}
// Len .
func (a *RtAttr) Len() int {
if len(a.children) == 0 {
return (syscall.SizeofRtAttr + len(a.Data))
}
l := 0
for _, child := range a.children {
l += rtaAlignOf(child.Len())
}
l += syscall.SizeofRtAttr
return rtaAlignOf(l + len(a.Data))
}
// Serialize the RtAttr into a byte array
// This can't just unsafe.cast because it must iterate through children.
func (a *RtAttr) Serialize() []byte {
native := NativeEndian()
length := a.Len()
buf := make([]byte, rtaAlignOf(length))
next := 4
if a.Data != nil {
copy(buf[next:], a.Data)
next += rtaAlignOf(len(a.Data))
}
if len(a.children) > 0 {
for _, child := range a.children {
childBuf := child.Serialize()
copy(buf[next:], childBuf)
next += rtaAlignOf(len(childBuf))
}
}
if l := uint16(length); l != 0 {
native.PutUint16(buf[0:2], l)
}
native.PutUint16(buf[2:4], a.Type)
return buf
}
// NetlinkRequest .
type NetlinkRequest struct {
syscall.NlMsghdr
Data []NetlinkRequestData
RawData []byte
}
// NewNetlinkRequest create a new netlink request from proto and flags
// Note the Len value will be inaccurate once data is added until
// the message is serialized
func NewNetlinkRequest(proto, flags int) *NetlinkRequest {
return &NetlinkRequest{
NlMsghdr: syscall.NlMsghdr{
Len: uint32(syscall.SizeofNlMsghdr),
Type: uint16(proto),
Flags: syscall.NLM_F_REQUEST | uint16(flags),
Seq: atomic.AddUint32(&nextSeqNr, 1),
// Pid: uint32(os.Getpid()),
},
}
}
// Serialize the Netlink Request into a byte array
func (req *NetlinkRequest) Serialize() []byte {
length := syscall.SizeofNlMsghdr
dataBytes := make([][]byte, len(req.Data))
for i, data := range req.Data {
dataBytes[i] = data.Serialize()
length = length + len(dataBytes[i])
}
length += len(req.RawData)
req.Len = uint32(length)
b := make([]byte, length)
hdr := (*(*[syscall.SizeofNlMsghdr]byte)(unsafe.Pointer(req)))[:]
next := syscall.SizeofNlMsghdr
copy(b[0:next], hdr)
for _, data := range dataBytes {
for _, dataByte := range data {
b[next] = dataByte
next = next + 1
}
}
// Add the raw data if any
if len(req.RawData) > 0 {
copy(b[next:length], req.RawData)
}
return b
}
// AddData add data to request
func (req *NetlinkRequest) AddData(data NetlinkRequestData) {
if data != nil {
req.Data = append(req.Data, data)
}
}
// AddRawData adds raw bytes to the end of the NetlinkRequest object during serialization
func (req *NetlinkRequest) AddRawData(data []byte) {
if data != nil {
req.RawData = append(req.RawData, data...)
}
}
// Uint8Attr .
func Uint8Attr(v uint8) []byte {
return []byte{byte(v)}
}
// Uint16Attr .
func Uint16Attr(v uint16) []byte {
native := NativeEndian()
bytes := make([]byte, 2)
native.PutUint16(bytes, v)
return bytes
}
// Uint32Attr .
func Uint32Attr(v uint32) []byte {
native := NativeEndian()
bytes := make([]byte, 4)
native.PutUint32(bytes, v)
return bytes
}
// ZeroTerminated .
func ZeroTerminated(s string) []byte {
bytes := make([]byte, len(s)+1)
for i := 0; i < len(s); i++ {
bytes[i] = s[i]
}
bytes[len(s)] = 0
return bytes
}
// NonZeroTerminated .
func NonZeroTerminated(s string) []byte {
bytes := make([]byte, len(s))
for i := 0; i < len(s); i++ {
bytes[i] = s[i]
}
return bytes
}
// BytesToString .
func BytesToString(b []byte) string {
n := bytes.Index(b, []byte{0})
return string(b[:n])
}