netlink/xfrm_state_linux.go
2014-08-31 20:34:46 -07:00

353 lines
8.3 KiB
Go

package netlink
import (
"fmt"
"syscall"
"unsafe"
)
const (
SizeofXfrmUsersaId = 0x18
SizeofXfrmStats = 0x0c
SizeofXfrmUsersaInfo = 0xe0
SizeofXfrmAlgo = 0x44
SizeofXfrmAlgoAuth = 0x48
)
// struct xfrm_usersa_id {
// xfrm_address_t daddr;
// __be32 spi;
// __u16 family;
// __u8 proto;
// };
type XfrmUsersaId struct {
Daddr XfrmAddress
Spi uint32 // big endian
Family uint16
Proto uint8
Pad byte
}
func (msg *XfrmUsersaId) Len() int {
return SizeofXfrmUsersaId
}
func DeserializeXfrmUsersaId(b []byte) *XfrmUsersaId {
return (*XfrmUsersaId)(unsafe.Pointer(&b[0:SizeofXfrmUsersaId][0]))
}
func (msg *XfrmUsersaId) Serialize() []byte {
return (*(*[SizeofXfrmUsersaId]byte)(unsafe.Pointer(msg)))[:]
}
// struct xfrm_stats {
// __u32 replay_window;
// __u32 replay;
// __u32 integrity_failed;
// };
type XfrmStats struct {
ReplayWindow uint32
Replay uint32
IntegrityFailed uint32
}
func (msg *XfrmStats) Len() int {
return SizeofXfrmStats
}
func DeserializeXfrmStats(b []byte) *XfrmStats {
return (*XfrmStats)(unsafe.Pointer(&b[0:SizeofXfrmStats][0]))
}
func (msg *XfrmStats) Serialize() []byte {
return (*(*[SizeofXfrmStats]byte)(unsafe.Pointer(msg)))[:]
}
// struct xfrm_usersa_info {
// struct xfrm_selector sel;
// struct xfrm_id id;
// xfrm_address_t saddr;
// struct xfrm_lifetime_cfg lft;
// struct xfrm_lifetime_cur curlft;
// struct xfrm_stats stats;
// __u32 seq;
// __u32 reqid;
// __u16 family;
// __u8 mode; /* XFRM_MODE_xxx */
// __u8 replay_window;
// __u8 flags;
// #define XFRM_STATE_NOECN 1
// #define XFRM_STATE_DECAP_DSCP 2
// #define XFRM_STATE_NOPMTUDISC 4
// #define XFRM_STATE_WILDRECV 8
// #define XFRM_STATE_ICMP 16
// #define XFRM_STATE_AF_UNSPEC 32
// #define XFRM_STATE_ALIGN4 64
// #define XFRM_STATE_ESN 128
// };
//
// #define XFRM_SA_XFLAG_DONT_ENCAP_DSCP 1
//
type XfrmUsersaInfo struct {
Sel XfrmSelector
Id XfrmId
Saddr XfrmAddress
Lft XfrmLifetimeCfg
Curlft XfrmLifetimeCur
Stats XfrmStats
Seq uint32
Reqid uint32
Family uint16
Mode uint8
ReplayWindow uint8
Flags uint8 // TODO: investigate enum
Pad [7]byte
}
func (msg *XfrmUsersaInfo) Len() int {
return SizeofXfrmUsersaInfo
}
func DeserializeXfrmUsersaInfo(b []byte) *XfrmUsersaInfo {
return (*XfrmUsersaInfo)(unsafe.Pointer(&b[0:SizeofXfrmUsersaInfo][0]))
}
func (msg *XfrmUsersaInfo) Serialize() []byte {
return (*(*[SizeofXfrmUsersaInfo]byte)(unsafe.Pointer(msg)))[:]
}
// struct xfrm_algo {
// char alg_name[64];
// unsigned int alg_key_len; /* in bits */
// char alg_key[0];
// };
type XfrmAlgo struct {
AlgName [64]byte
AlgKeyLen uint32
AlgKey []byte
}
func (msg *XfrmAlgo) Len() int {
return SizeofXfrmAlgo + int(msg.AlgKeyLen/8)
}
func DeserializeXfrmAlgo(b []byte) *XfrmAlgo {
ret := XfrmAlgo{}
copy(ret.AlgName[:], b[0:64])
ret.AlgKeyLen = *(*uint32)(unsafe.Pointer(&b[64]))
ret.AlgKey = b[68:ret.Len()]
return &ret
}
func (msg *XfrmAlgo) Serialize() []byte {
b := make([]byte, msg.Len())
copy(b[0:64], msg.AlgName[:])
copy(b[64:68], (*(*[4]byte)(unsafe.Pointer(&msg.AlgKeyLen)))[:])
copy(b[68:msg.Len()], msg.AlgKey[:])
return b
}
// struct xfrm_algo_auth {
// char alg_name[64];
// unsigned int alg_key_len; /* in bits */
// unsigned int alg_trunc_len; /* in bits */
// char alg_key[0];
// };
type XfrmAlgoAuth struct {
AlgName [64]byte
AlgKeyLen uint32
AlgTruncLen uint32
AlgKey []byte
}
func (msg *XfrmAlgoAuth) Len() int {
return SizeofXfrmAlgoAuth + int(msg.AlgKeyLen/8)
}
func DeserializeXfrmAlgoAuth(b []byte) *XfrmAlgoAuth {
ret := XfrmAlgoAuth{}
copy(ret.AlgName[:], b[0:64])
ret.AlgKeyLen = *(*uint32)(unsafe.Pointer(&b[64]))
ret.AlgTruncLen = *(*uint32)(unsafe.Pointer(&b[68]))
ret.AlgKey = b[72:ret.Len()]
return &ret
}
func (msg *XfrmAlgoAuth) Serialize() []byte {
b := make([]byte, msg.Len())
copy(b[0:64], msg.AlgName[:])
copy(b[64:68], (*(*[4]byte)(unsafe.Pointer(&msg.AlgKeyLen)))[:])
copy(b[68:72], (*(*[4]byte)(unsafe.Pointer(&msg.AlgTruncLen)))[:])
copy(b[72:msg.Len()], msg.AlgKey[:])
return b
}
// struct xfrm_algo_aead {
// char alg_name[64];
// unsigned int alg_key_len; /* in bits */
// unsigned int alg_icv_len; /* in bits */
// char alg_key[0];
// }
// struct xfrm_encap_tmpl {
// __u16 encap_type;
// __be16 encap_sport;
// __be16 encap_dport;
// xfrm_address_t encap_oa;
// };
func writeStateAlgo(a *XfrmStateAlgo) []byte {
algo := XfrmAlgo{
AlgKeyLen: uint32(len(a.Key) * 8),
AlgKey: a.Key,
}
end := len(a.Name)
if end > 64 {
end = 64
}
copy(algo.AlgName[:end], a.Name)
return algo.Serialize()
}
func writeStateAlgoAuth(a *XfrmStateAlgo) []byte {
algo := XfrmAlgoAuth{
AlgKeyLen: uint32(len(a.Key) * 8),
AlgTruncLen: uint32(a.TruncateLen),
AlgKey: a.Key,
}
end := len(a.Name)
if end > 64 {
end = 64
}
copy(algo.AlgName[:end], a.Name)
return algo.Serialize()
}
// XfrmStateAdd will add an xfrm state to the system.
// Equivalent to: `ip xfrm state add $state`
func XfrmStateAdd(state *XfrmState) error {
// A state with spi 0 can't be deleted so don't allow it to be set
if state.Spi == 0 {
return fmt.Errorf("Spi must be set when adding xfrm state.")
}
req := newNetlinkRequest(XFRM_MSG_NEWSA, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK)
msg := &XfrmUsersaInfo{}
msg.Family = uint16(GetIPFamily(state.Dst))
msg.Id.Daddr.FromIP(state.Dst)
msg.Saddr.FromIP(state.Src)
msg.Id.Proto = uint8(state.Proto)
msg.Mode = uint8(state.Mode)
msg.Id.Spi = swap32(uint32(state.Spi))
msg.Reqid = uint32(state.Reqid)
req.AddData(msg)
if state.Auth != nil {
out := newRtAttr(XFRMA_ALG_AUTH_TRUNC, writeStateAlgoAuth(state.Auth))
req.AddData(out)
}
if state.Crypt != nil {
out := newRtAttr(XFRMA_ALG_CRYPT, writeStateAlgo(state.Crypt))
req.AddData(out)
}
_, err := req.Execute(syscall.NETLINK_XFRM, 0)
return err
}
// XfrmStateDel will delete an xfrm state from the system. Note that
// the Algos are ignored when matching the state to delete.
// Equivalent to: `ip xfrm state del $state`
func XfrmStateDel(state *XfrmState) error {
req := newNetlinkRequest(XFRM_MSG_DELSA, syscall.NLM_F_ACK)
msg := &XfrmUsersaId{}
msg.Daddr.FromIP(state.Dst)
msg.Family = uint16(GetIPFamily(state.Dst))
msg.Proto = uint8(state.Proto)
msg.Spi = swap32(uint32(state.Spi))
req.AddData(msg)
saddr := XfrmAddress{}
saddr.FromIP(state.Src)
srcdata := newRtAttr(XFRMA_SRCADDR, saddr.Serialize())
req.AddData(srcdata)
_, err := req.Execute(syscall.NETLINK_XFRM, 0)
return err
}
// XfrmStateList gets a list of xfrm states in the system.
// Equivalent to: `ip xfrm state show`.
// The list can be filtered by ip family.
func XfrmStateList(family int) ([]XfrmState, error) {
req := newNetlinkRequest(XFRM_MSG_GETSA, syscall.NLM_F_DUMP)
msg := newIfInfomsg(family)
req.AddData(msg)
msgs, err := req.Execute(syscall.NETLINK_XFRM, XFRM_MSG_NEWSA)
if err != nil {
return nil, err
}
res := make([]XfrmState, 0)
for _, m := range msgs {
msg := DeserializeXfrmUsersaInfo(m)
if family != FAMILY_ALL && family != int(msg.Family) {
continue
}
var state XfrmState
state.Dst = msg.Id.Daddr.ToIP()
state.Src = msg.Saddr.ToIP()
state.Proto = Proto(msg.Id.Proto)
state.Mode = Mode(msg.Mode)
state.Spi = int(swap32(msg.Id.Spi))
state.Reqid = int(msg.Reqid)
attrs, err := parseRouteAttr(m[msg.Len():])
if err != nil {
return nil, err
}
for _, attr := range attrs {
switch attr.Attr.Type {
case XFRMA_ALG_AUTH, XFRMA_ALG_CRYPT:
var resAlgo *XfrmStateAlgo
if attr.Attr.Type == XFRMA_ALG_AUTH {
if state.Auth == nil {
state.Auth = new(XfrmStateAlgo)
}
resAlgo = state.Auth
} else {
state.Crypt = new(XfrmStateAlgo)
resAlgo = state.Crypt
}
algo := DeserializeXfrmAlgo(attr.Value[:])
(*resAlgo).Name = bytesToString(algo.AlgName[:])
(*resAlgo).Key = algo.AlgKey
case XFRMA_ALG_AUTH_TRUNC:
if state.Auth == nil {
state.Auth = new(XfrmStateAlgo)
}
algo := DeserializeXfrmAlgoAuth(attr.Value[:])
state.Auth.Name = bytesToString(algo.AlgName[:])
state.Auth.Key = algo.AlgKey
state.Auth.TruncateLen = int(algo.AlgTruncLen)
}
}
res = append(res, state)
}
return res, nil
}