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clean up tcp package; add Abort method

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This commit is contained in:
soypat
2025-02-24 09:25:55 -03:00
parent d996040d92
commit d04d287ab6
6 changed files with 139 additions and 68 deletions
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examples/stack/main.go
+56 -41
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@@ -56,40 +56,39 @@ func main() {
if err != nil {
log.Fatal(err)
}
tap := NewHTTPTap("http://127.0.0.1:7070")
// tap, err := internal.NewTap("tap0", iface)
if err != nil {
log.Fatal(err)
}
defer tap.Close()
fmt.Println("hosting server at ", addrPort.String())
var buf [mtu]byte
for {
n, err := tap.Read(buf[:])
nread, err := tap.Read(buf[:])
if err != nil {
slogger.error("tap-err", slog.String("err", err.Error()))
log.Fatal(err)
} else if n > 0 {
err = lStack.RecvEth(buf[:n])
} else if nread > 0 {
err = lStack.RecvEth(buf[:nread])
if err != nil {
slogger.error("recv", slog.String("err", err.Error()), slog.Int("plen", n))
slogger.error("recv", slog.String("err", err.Error()), slog.Int("plen", nread))
} else {
slogger.info("recv", slog.Int("plen", n))
slogger.info("recv", slog.Int("plen", nread))
}
} else if n == 0 {
time.Sleep(250 * time.Millisecond)
}
n, err = lStack.HandleEth(buf[:])
nw, err := lStack.HandleEth(buf[:])
if err != nil {
slogger.error("handle", slog.String("err", err.Error()))
} else if n > 0 {
_, err = tap.Write(buf[:n])
} else if nw > 0 {
_, err = tap.Write(buf[:nw])
if err != nil {
log.Fatal(err)
} else {
slogger.info("write", slog.Int("plen", n))
slogger.info("write", slog.Int("plen", nw))
}
}
if nread == 0 && nw == 0 {
time.Sleep(5 * time.Millisecond)
}
}
}
@@ -337,6 +336,10 @@ func (is *IPv4Stack) Handle(ethFrame []byte, ipOff int) (int, error) {
ifrm.SetFlags(dontFrag)
ifrm.SetTTL(64)
ifrm.SetCRC(ifrm.CalculateHeaderCRC())
if ifrm.Protocol() == lneto2.IPProtoTCP {
tfrm, _ := tcp.NewFrame(ifrm.Payload())
is.info("IPv4Stack:send", slog.String("ip", ifrm.String()), slog.String("tcp", tfrm.String()))
}
return totalLen, nil
}
}
@@ -347,7 +350,6 @@ type TCPStack struct {
validator lneto2.Validator
handlers []handler
logger
crc lneto2.CRC791
}
func (ts *TCPStack) Protocol() uint32 { return uint32(lneto2.IPProtoTCP) }
@@ -389,20 +391,9 @@ func (ts *TCPStack) Recv(ipFrame []byte, tcpOff int) error {
if err = ts.validator.Err(); err != nil {
return err
}
ts.crc.Reset()
switch ipVersion {
case 4:
ifrm, _ := ipv4.NewFrame(ipFrame)
ifrm.CRCWriteTCPPseudo(&ts.crc)
ts.log.Info("tcpStack:recv", slog.String("ipfrm", ifrm.String()), slog.String("frame", tfrm.String()))
case 6:
i6frm, _ := ipv6.NewFrame(ipFrame)
i6frm.CRCWritePseudo(&ts.crc)
}
tfrm.CRCWrite(&ts.crc)
crc := ts.crc.Sum16()
crc := tcpChecksum(ipFrame, len(tfrm.RawData()))
gotCRC := tfrm.CRC()
if ts.crc.Sum16() != gotCRC {
if crc != gotCRC {
ts.error("TCPStack:Recv:crc-mismatch", slog.Uint64("lport", uint64(lport)), slog.Uint64("want", uint64(crc)), slog.Uint64("got", uint64(gotCRC)))
return errors.New("TCP crc mismatch")
}
@@ -428,6 +419,7 @@ func (ts *TCPStack) Handle(ipFrame []byte, tcpOff int) (n int, err error) {
}
}
if n > 0 {
ipFrame = ipFrame[:tcpOff+n]
break
}
}
@@ -435,24 +427,14 @@ func (ts *TCPStack) Handle(ipFrame []byte, tcpOff int) (n int, err error) {
return 0, err
}
// TCP packet written.
tfrm, _ := tcp.NewFrame(ipFrame[tcpOff : tcpOff+n])
tfrm, _ := tcp.NewFrame(ipFrame[tcpOff:])
ts.validator.ResetErr()
tfrm.ValidateSize(&ts.validator) // Perform basic validation.
if err = ts.validator.Err(); err != nil {
return 0, err
}
ts.crc.Reset()
switch ipVersion {
case 4:
ifrm, _ := ipv4.NewFrame(ipFrame)
ifrm.CRCWriteTCPPseudo(&ts.crc)
ts.log.Info("tcpStack:send", slog.String("ipfrm", ifrm.String()), slog.String("frame", tfrm.String()))
case 6:
i6frm, _ := ipv6.NewFrame(ipFrame)
i6frm.CRCWritePseudo(&ts.crc)
}
crc := ts.crc.Sum16()
crc := tcpChecksum(ipFrame, n)
tfrm.SetCRC(crc)
return n, nil
}
@@ -554,6 +536,12 @@ func NewHTTPTap(baseURL string) *HTTPTap {
return &h
}
type TAPNop struct{}
func (h *TAPNop) Read(b []byte) (int, error) { return 0, nil }
func (h *TAPNop) Write(b []byte) (int, error) { return 0, nil }
func (h *TAPNop) Close() error { return nil }
type HTTPTap struct {
c http.Client
recvurl string
@@ -590,3 +578,30 @@ func (h *HTTPTap) Write(b []byte) (int, error) {
}
func (h *HTTPTap) Close() error { return nil }
func tcpChecksum(ipFrame []byte, tcpPayload int) uint16 {
version := ipFrame[0] >> 4
var tfrm tcp.Frame
var crc lneto2.CRC791
switch version {
case 4:
ifrm, _ := ipv4.NewFrame(ipFrame)
crc.Write(ifrm.SourceAddr()[:])
crc.Write(ifrm.DestinationAddr()[:])
crc.AddUint16(uint16(tcpPayload))
crc.AddUint16(6)
tfrm, _ = tcp.NewFrame(ifrm.Payload())
case 6:
i6frm, _ := ipv6.NewFrame(ipFrame)
crc.Write(i6frm.SourceAddr()[:])
crc.Write(i6frm.DestinationAddr()[:])
crc.AddUint32(uint32(tcpPayload))
crc.AddUint32(6)
i6frm.CRCWritePseudo(&crc)
tfrm, _ = tcp.NewFrame(i6frm.Payload())
default:
panic("invalid IP version")
}
tfrm.CRCWrite(&crc)
return crc.Sum16()
}