func Run() {
// defaults
fname := "samtun.json"
only_print_dest := false
if len(os.Args) > 1 {
if os.Args[1] == "-h" || os.Args[1] == "--help" {
// print usage and return
fmt.Fprintf(os.Stdout, "usage: %s [config.json]\n", os.Args[0])
return
} else if os.Args[1] == "--dest" {
// print out destination
only_print_dest = true
} else {
fname = os.Args[1]
}
}
if !checkfile(fname) {
// generate a config we don't have it there
conf := genConfig(fname)
conf.Save(fname)
}
conf, err := loadConfig(fname)
if err == nil {
// we are configured correctly
ip, _, err := net.ParseCIDR(conf.Addr)
if err != nil {
log.Println("invalid address", conf.Addr)
return
}
Map := make(addrMap)
// we have a sam connection
var keys sam3.I2PKeys
if !checkfile(conf.Keyfile) {
log.Println("connecting to", conf.Sam)
sam, err := sam3.NewSAM(conf.Sam)
if err == nil {
// we have not generated private keys yet
log.Println("generating keys")
keys, err = sam.NewKeys()
sam.Close()
ioutil.WriteFile(conf.Keyfile, []byte(keys.String()+" "+keys.Addr().String()), 0600)
// load addr map if it is there
if checkfile(conf.MapFile) {
Map, _ = loadAddrMap(conf.MapFile)
}
b32 := keys.Addr().Base32()
Map[b32] = []string{conf.Addr}
err = saveAddrMap(conf.MapFile, Map)
if err != nil {
log.Println("failed to save address map", err)
return
}
} else {
log.Fatal(err)
}
}
key_bytes, err := ioutil.ReadFile(conf.Keyfile)
if err == nil {
// read the keys
key_str := string(key_bytes)
privkey := strings.Split(key_str, " ")[0]
pubkey := strings.Split(key_str, " ")[1]
keys := sam3.NewKeys(sam3.I2PAddr(pubkey), privkey)
log.Println("our destination is", keys.Addr().Base32())
if only_print_dest {
return
}
// load address map
Map, err = loadAddrMap(conf.MapFile)
if err != nil {
log.Fatal(err)
}
// create our datagram session
log.Println("creating session")
var opts []string
// set up sam options
if conf.SamOpts == nil {
opts = sam3.Options_Small
} else {
for k, v := range conf.SamOpts {
opts = append(opts, fmt.Sprintf("%s=%s", k, v))
}
}
sam, err := sam3.NewSAM(conf.Sam)
if err == nil {
dg, err := sam.NewDatagramSession(conf.Session, keys, opts, 0)
defer dg.Close()
if err == nil {
log.Println("session made")
ourAddr, err := sam.Lookup("ME")
if err != nil {
log.Println("failed to lookup our own destination")
return
}
log.Println("we are", ourAddr.Base32())
iface, err := newTun(conf.Ifname, ip.String(), conf.Netmask, conf.MTU)
if err != nil {
log.Fatalf("failed to create network interface %s", err.Error())
}
defer iface.Close()
tunpkt_inchnl := make(chan []byte)
//tunpkt_outchnl := make(chan []byte)
sampkt_inchnl := make(chan linkMessage)
//sampkt_outchnl := make(chan linkMessage)
// read packets from tun
go func() {
for {
pktbuff := make([]byte, conf.MTU+64)
n, err := iface.Read(pktbuff[:])
if err == nil {
tunpkt_inchnl <- pktbuff[:n]
} else {
log.Println("error while reading tun packet", err)
time.Sleep(time.Second)
}
}
}()
// read packets from sam
go func() {
for {
pktbuff := make([]byte, conf.MTU+64)
n, from, err := dg.ReadFrom(pktbuff)
if err == nil {
// lookup ip from address map
if Map.AllowDest(from.Base32()) {
// got from sam
sampkt_inchnl <- linkMessage{pkt: pktbuff[:n], addr: from}
} else {
// unwarrented
log.Println("unwarrented packet from", from.Base32())
}
} else {
log.Println("error while reading sam packet", err)
close(sampkt_inchnl)
return
}
}
}()
lookup_chnl := make(chan string, 8)
lookup_result_chnl := make(chan sam3.I2PAddr, 8)
go func() {
// lookup destinations goroutine
for {
b32 := <-lookup_chnl
log.Println("lookup", b32)
dest, err := sam.Lookup(b32)
if err == nil {
log.Println("found", b32)
lookup_result_chnl <- dest
}
}
}()
done_chnl := make(chan bool)
// sam send routine
go func() {
// b32 -> b64 cache
dest_cache := make(map[string]sam3.I2PAddr)
for {
select {
case addr, ok := <-lookup_result_chnl:
if ok {
dest_cache[addr.Base32()] = addr
}
case data, ok := <-tunpkt_inchnl:
if ok {
pkt := ipPacket(data)
dst := pkt.Dst()
b32 := Map.B32(dst)
if len(b32) == 0 {
log.Println("cannot send packet to", dst, "unknown endpoint")
} else {
dest, ok := dest_cache[b32]
if ok {
_, err := dg.WriteTo(pkt[:], dest)
if err == nil {
// we gud
} else {
log.Println("error writing to remote destination", err)
done_chnl <- true
return
}
} else {
// cache miss
// TODO: deadlock
lookup_chnl <- b32
}
}
} else {
done_chnl <- true
return
}
}
}
}()
// write tun packet routine
go func() {
for {
msg, ok := <-sampkt_inchnl
if ok {
pkt := Map.filterMessage(msg, ourAddr)
if pkt == nil {
// invalid frame D:
log.Println("invalid frame from", msg.addr.Base32())
} else {
_, err := iface.Write(pkt)
if err == nil {
// we gud
} else {
log.Println("error writing to tun interface", err)
done_chnl <- true
return
}
}
} else {
done_chnl <- true
return
}
}
}()
<-done_chnl
log.Println("closing")
} else {
log.Fatal(err)
}
} else {
log.Fatal(err)
}
} else {
log.Fatal(err)
}
} else {
log.Fatal(err)
}
}
func saveI2PKey(key i2p.I2PKeys, fname string) (err error) {
return ioutil.WriteFile(fname, []byte(key.Addr().String()+"\n"+key.String()), 0600)
}