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package main
import (
"bytes"
"crypto/hmac"
"crypto/sha256"
"crypto/tls"
"crypto/x509"
"encoding/binary"
"encoding/json"
"flag"
"fmt"
"io"
"io/ioutil"
"log"
"net"
"os"
"os/signal"
"strconv"
"strings"
"time"
config "github.com/D4-project/d4-golang-utils/config"
uuid "github.com/D4-project/d4-golang-utils/crypto/hash"
)
const (
// VERSION_SIZE
VERSION_SIZE = 1
// TYPE_SIZE
TYPE_SIZE = 1
// UUID_SIZE
UUID_SIZE = 16
// TIMESTAMP_SIZE
TIMESTAMP_SIZE = 8
// HMAC_SIZE
HMAC_SIZE = 32
// SSIZE payload size size
SSIZE = 4
// HDR_SIZE total header size
HDR_SIZE = VERSION_SIZE + TYPE_SIZE + UUID_SIZE + HMAC_SIZE + TIMESTAMP_SIZE + SSIZE
// MH_FILE_LIMIT defines in bytes the max size of the json meta header file
MH_FILE_LIMIT = 100000
)
type (
// A d4 writer implements the io.Writer Interface by implementing Write() and Close()
// it accepts an io.Writer as sink
d4Writer struct {
w io.Writer
key []byte
fb []byte
pb []byte
}
d4S struct {
src io.Reader
dst d4Writer
confdir string
cka time.Duration
ct time.Duration
ce bool
retry time.Duration
cc bool
ca x509.CertPool
d4error uint8
errnoCopy uint8
debug bool
conf d4params
mhb *bytes.Buffer
mh []byte
}
d4params struct {
uuid []byte
snaplen uint32
key []byte
version uint8
source string
destination string
ttype uint8
}
)
var (
// verbose
buf bytes.Buffer
logger = log.New(&buf, "INFO: ", log.Lshortfile)
infof = func(info string) {
logger.Output(2, info)
}
tmpct, _ = time.ParseDuration("5mn")
tmpcka, _ = time.ParseDuration("30s")
tmpretry, _ = time.ParseDuration("30s")
confdir = flag.String("c", "", "configuration directory")
debug = flag.Bool("v", false, "Set to True, true, TRUE, 1, or t to enable verbose output on stdout")
ce = flag.Bool("ce", true, "Set to True, true, TRUE, 1, or t to enable TLS on network destination")
ct = flag.Duration("ct", tmpct, "Set timeout in human format")
cka = flag.Duration("cka", tmpcka, "Keep Alive time human format, 0 to disable")
retry = flag.Duration("rt", tmpretry, "Time in human format before retry after connection failure, set to 0 to exit on failure")
cc = flag.Bool("cc", false, "Check TLS certificate against rootCA.crt")
)
func main() {
var d4 d4S
d4p := &d4
flag.Usage = func() {
fmt.Printf("d4 - d4 client\n")
fmt.Printf("Read data from the configured <source> and send it to <destination>\n")
fmt.Printf("\n")
fmt.Printf("Usage: d4 -c config_directory\n")
fmt.Printf("\n")
fmt.Printf("Configuration\n\n")
fmt.Printf("The configuration settings are stored in files in the configuration directory\n")
fmt.Printf("specified with the -c command line switch.\n\n")
fmt.Printf("Files in the configuration directory\n")
fmt.Printf("\n")
fmt.Printf("key - is the private HMAC-SHA-256-128 key.\n")
fmt.Printf(" The HMAC is computed on the header with a HMAC value set to 0\n")
fmt.Printf(" which is updated later.\n")
fmt.Printf("snaplen - the length of bytes that is read from the <source>\n")
fmt.Printf("version - the version of the d4 client\n")
fmt.Printf("type - the type of data that is send. pcap, netflow, ...\n")
fmt.Printf("source - the source where the data is read from\n")
fmt.Printf("destination - the destination where the data is written to\n")
fmt.Printf("\n")
flag.PrintDefaults()
}
flag.Parse()
if flag.NFlag() == 0 || *confdir == "" {
flag.Usage()
os.Exit(1)
} else {
*confdir = strings.TrimSuffix(*confdir, "/")
*confdir = strings.TrimSuffix(*confdir, "\\")
}
d4.confdir = *confdir
d4.ce = *ce
d4.ct = *ct
d4.cc = *cc
d4.cka = *cka
d4.retry = *retry
s := make(chan os.Signal, 1)
signal.Notify(s, os.Interrupt, os.Kill)
c := make(chan string)
k := make(chan string)
d4.mhb = bytes.NewBuffer(d4.mh)
for {
// init or reinit after retry
if set(d4p) {
// type 254 requires to send a meta-header first
if d4.conf.ttype == 254 || d4.conf.ttype == 2 {
// create a jsonreader
d4p.dst.hijackHeader()
// Ugly hack to skip bytes.Buffer WriteTo check that bypasses my fixed lenght buffer
nread, err := io.CopyBuffer(&d4.dst, struct{ io.Reader }{d4.mhb}, d4.dst.pb)
if err != nil {
panic(fmt.Sprintf("Cannot initiate session %s", err))
}
infof(fmt.Sprintf("Meta-Header sent: %d bytes", nread))
d4p.dst.restoreHeader()
}
// copy routine
go d4Copy(d4p, c, k)
} else if d4.retry > 0 {
go func() {
infof(fmt.Sprintf("Sleeping for %.f seconds before retry...\n", d4.retry.Seconds()))
fmt.Printf("Sleeping for %.f seconds before retry...\n", d4.retry.Seconds())
time.Sleep(d4.retry)
c <- "done waiting"
}()
} else {
panic("Unrecoverable error without retry.")
}
// Block until we catch an event
select {
case str := <-c:
infof(str)
continue
case str := <-k:
fmt.Println(str)
exit(d4p, 1)
case <-s:
fmt.Println(" Exiting")
exit(d4p, 0)
}
}
}
func exit(d4 *d4S, exitcode int) {
// Output logging before closing if debug is enabled
if *debug == true {
(*d4).debug = true
fmt.Print(&buf)
}
os.Exit(exitcode)
}
func set(d4 *d4S) bool {
if d4loadConfig(d4) {
if setReaderWriters(d4) {
if d4.dst.initHeader(d4) {
return true
}
}
}
return false
}
func d4Copy(d4 *d4S, c chan string, k chan string) {
nread, err := io.CopyBuffer(&d4.dst, d4.src, d4.dst.pb)
if err != nil {
if (d4.retry.Seconds()) > 0 {
c <- fmt.Sprintf("%s", err)
return
}
k <- fmt.Sprintf("%s", err)
return
}
k <- fmt.Sprintf("EOF: Nread: %d", nread)
return
}
func readConfFile(d4 *d4S, fileName string) []byte {
return config.ReadConfigFile((*d4).confdir, fileName)
}
func d4loadConfig(d4 *d4S) bool {
// populate the map
(*d4).conf = d4params{}
(*d4).conf.source = string(readConfFile(d4, "source"))
if len((*d4).conf.source) < 1 {
log.Fatal("Unsupported source")
}
(*d4).conf.destination = string(readConfFile(d4, "destination"))
if len((*d4).conf.destination) < 1 {
log.Fatal("Unsupported Destination")
}
tmpu, err := uuid.FromString(string(readConfFile(d4, "uuid")))
if err != nil {
// generate new uuid
(*d4).conf.uuid = generateUUIDv4()
// And push it into the conf file
f, err := os.OpenFile((*d4).confdir+"/uuid", os.O_WRONLY, 0666)
defer f.Close()
if err != nil {
log.Fatal(err)
}
// store as canonical representation
f.WriteString(fmt.Sprintf("%s", uuid.FromBytesOrNil((*d4).conf.uuid)) + "\n")
} else {
(*d4).conf.uuid = tmpu.Bytes()
}
// parse snaplen to uint32
tmp, err := strconv.ParseUint(string(readConfFile(d4, "snaplen")), 10, 32)
if err != nil || tmp < 1 {
(*d4).conf.snaplen = uint32(4096)
} else {
(*d4).conf.snaplen = uint32(tmp)
}
(*d4).conf.key = readConfFile(d4, "key")
// parse version to uint8
tmp, _ = strconv.ParseUint(string(readConfFile(d4, "version")), 10, 8)
if err != nil || tmp < 1 {
(*d4).conf.version = uint8(1)
} else {
(*d4).conf.version = uint8(tmp)
}
// parse type to uint8
tmp, _ = strconv.ParseUint(string(readConfFile(d4, "type")), 10, 8)
if err != nil || tmp < 1 {
log.Fatal("Unsupported type")
} else {
(*d4).conf.ttype = uint8(tmp)
}
// parse meta header file
data := make([]byte, MH_FILE_LIMIT)
if tmp == 254 || tmp == 2 {
file, err := os.Open((*d4).confdir + "/metaheader.json")
defer file.Close()
if err != nil {
panic("Failed to open Meta-Header File.")
} else {
if count, err := file.Read(data); err != nil {
panic("Failed to open Meta-Header File.")
} else {
if json.Valid(data[:count]) {
if checkType(data[:count]) {
if off, err := file.Seek(0, 0); err != nil || off != 0 {
panic(fmt.Sprintf("Cannot read Meta-Header file: %s", err))
} else {
if err := json.Compact((*d4).mhb, data[:count]); err != nil {
infof("Failed to compact meta header file")
}
}
} else {
panic("A Meta-Header File should at least contain a 'type' field.")
}
} else {
panic("Failed to validate open Meta-Header File.")
}
}
}
}
// Add the custom CA cert in D4 certpool
if (*d4).cc {
certb, _ := ioutil.ReadFile((*d4).confdir + "rootCA.crt")
(*d4).ca = *x509.NewCertPool()
ok := (*d4).ca.AppendCertsFromPEM(certb)
if !ok {
panic("Failed to parse provided root certificate.")
}
}
return true
}
func checkType(b []byte) bool {
var f interface{}
if err := json.Unmarshal(b, &f); err != nil {
return false
}
m := f.(map[string]interface{})
for k, v := range m {
if k == "type" {
switch v.(type) {
case string:
if v != nil {
return true
}
}
}
}
return false
}
func newD4Writer(writer io.Writer, key []byte) d4Writer {
return d4Writer{w: writer, key: key}
}
// TODO QUICK IMPLEM, REVISE
func setReaderWriters(d4 *d4S) bool {
//TODO implement other destination file, fifo unix_socket ...
switch (*d4).conf.source {
case "stdin":
(*d4).src = os.Stdin
case "pcap":
f, _ := os.Open("capture.pcap")
(*d4).src = f
}
isn, dstnet := config.IsNet((*d4).conf.destination)
if isn {
dial := net.Dialer{
Timeout: (*d4).ct,
KeepAlive: (*d4).cka,
FallbackDelay: 0,
}
tlsc := tls.Config{
InsecureSkipVerify: true,
}
if (*d4).cc {
tlsc = tls.Config{
InsecureSkipVerify: false,
RootCAs: &(*d4).ca,
}
}
if (*d4).ce == true {
conn, errc := tls.DialWithDialer(&dial, "tcp", dstnet, &tlsc)
if errc != nil {
fmt.Println(errc)
return false
}
(*d4).dst = newD4Writer(conn, (*d4).conf.key)
} else {
conn, errc := dial.Dial("tcp", dstnet)
if errc != nil {
return false
}
(*d4).dst = newD4Writer(conn, (*d4).conf.key)
}
} else {
switch (*d4).conf.destination {
case "stdout":
(*d4).dst = newD4Writer(os.Stdout, (*d4).conf.key)
case "file":
f, _ := os.Create("test.txt")
(*d4).dst = newD4Writer(f, (*d4).conf.key)
default:
panic(fmt.Sprintf("No suitable destination found, given :%q", (*d4).conf.destination))
}
}
// Create the copy buffer
(*d4).dst.fb = make([]byte, HDR_SIZE+(*d4).conf.snaplen)
(*d4).dst.pb = make([]byte, (*d4).conf.snaplen)
return true
}
func generateUUIDv4() []byte {
uuid, err := uuid.NewV4()
if err != nil {
log.Fatal(err)
}
infof(fmt.Sprintf("UUIDv4: %s\n", uuid))
return uuid.Bytes()
}
func (d4w *d4Writer) Write(bs []byte) (int, error) {
// bs is pb
// zero out moving parts of the frame
copy(d4w.fb[18:62], make([]byte, 44))
copy(d4w.fb[62:], make([]byte, 62+len(bs)))
// update headers
d4w.updateHeader(len(bs))
// Copy payload after the header
copy(d4w.fb[62:62+len(bs)], bs)
// Now that the packet is complete, compute hmac
d4w.updateHMAC(len(bs))
// Eventually write binary in the sink
err := binary.Write(d4w.w, binary.LittleEndian, d4w.fb[:62+len(bs)])
return len(bs), err
}
// TODO write go idiomatic err return values
func (d4w *d4Writer) updateHeader(lenbs int) bool {
timeUnix := time.Now().Unix()
binary.LittleEndian.PutUint64(d4w.fb[18:26], uint64(timeUnix))
binary.LittleEndian.PutUint32(d4w.fb[58:62], uint32(lenbs))
return true
}
func (d4w *d4Writer) updateHMAC(ps int) bool {
h := hmac.New(sha256.New, d4w.key)
h.Write(d4w.fb[0:1])
h.Write(d4w.fb[1:2])
h.Write(d4w.fb[2:18])
h.Write(d4w.fb[18:26])
h.Write(make([]byte, 32))
h.Write(d4w.fb[58:62])
h.Write(d4w.fb[62 : 62+ps])
copy(d4w.fb[26:58], h.Sum(nil))
return true
}
func (d4w *d4Writer) initHeader(d4 *d4S) bool {
// zero out the header
copy(d4w.fb[:HDR_SIZE], make([]byte, HDR_SIZE))
// put version and type into the header
d4w.fb[0] = (*d4).conf.version
d4w.fb[1] = (*d4).conf.ttype
// put uuid into the header
copy(d4w.fb[2:18], (*d4).conf.uuid)
// timestamp
timeUnix := time.Now().UnixNano()
binary.LittleEndian.PutUint64(d4w.fb[18:26], uint64(timeUnix))
// hmac is set to zero during hmac operations, so leave it alone
// init size of payload at 0
binary.LittleEndian.PutUint32(d4w.fb[58:62], uint32(0))
infof(fmt.Sprintf("Initialized a %d bytes header:\n", HDR_SIZE))
infof(fmt.Sprintf("%b\n", d4w.fb[:HDR_SIZE]))
return true
}
// We use type 2 to send the meta header
func (d4w *d4Writer) hijackHeader() bool {
d4w.fb[1] = 2
return true
}
// Switch back the header to 254
func (d4w *d4Writer) restoreHeader() bool {
d4w.fb[1] = 254
return true
}