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StackNode refactor: add offsetToIP argument to Encapsulate

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This commit is contained in:
Patricio Whittingslow
2025-12-19 00:38:28 -03:00
parent eaa36a589a
commit 1554b89a08
22 changed files with 180 additions and 94 deletions
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README.md
+4 -4
View File
@@ -57,11 +57,11 @@ The following interface is implemented by networking stack nodes and the stack t
```go
type StackNode interface {
// Encapsulate receives a buffer the receiver must fill with data.
// The receiver's start byte is at carrierData[frameOffset].
Encapsulate(carrierData []byte, frameOffset int) (int, error)
// The receiver's start byte is at carrierData[offsetToFrame].
Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error)
// Demux receives a buffer the receiver must decode and pass on to corresponding child StackNode(s).
// The receiver's start byte is at carrierData[frameOffset].
Demux(carrierData []byte, frameOffset int) error
// The receiver's start byte is at carrierData[offsetToFrame].
Demux(carrierData []byte, offsetToFrame int) error
// LocalPort returns the port of the node if applicable or zero. Used for UDP/TCP nodes.
LocalPort() uint16
// Protocol returns the protocol of this node if applicable or zero. Usually either a ethernet.Type (EtherType) or lneto.IPProto (IP Protocol number).
arp/arp_test.go
+8 -8
View File
@@ -34,13 +34,13 @@ func TestHandler(t *testing.T) {
t.Fatal(err)
}
var buf, discard [64]byte
n, err := c1.Encapsulate(buf[:], 0)
n, err := c1.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Fatal("error on should be nop send:", err)
} else if n > 0 {
t.Fatal("should not send if no query")
}
n, err = c2.Encapsulate(buf[:], 0)
n, err = c2.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Fatal("error on should be nop send:", err)
} else if n > 0 {
@@ -50,11 +50,11 @@ func TestHandler(t *testing.T) {
// Perform ARP exchange.
expectHWAddr := c2.ourHWAddr
queryAddr := c2.ourProtoAddr
err = c1.StartQuery(queryAddr)
err = c1.StartQuery(nil, queryAddr)
if err != nil {
t.Fatal(err)
}
n, err = c1.Encapsulate(buf[:], 0) // Send Request.
n, err = c1.Encapsulate(buf[:], -1, 0) // Send Request.
if err != nil {
t.Fatal(err)
} else if n == 0 {
@@ -66,14 +66,14 @@ func TestHandler(t *testing.T) {
t.Fatal(err)
}
n, err = c2.Encapsulate(buf[:], 0) // Send response.
n, err = c2.Encapsulate(buf[:], -1, 0) // Send response.
if err != nil {
t.Fatal(err)
} else if n == 0 {
t.Fatal("got no response to request")
}
validateARP(t, buf[:])
n, err = c2.Encapsulate(discard[:], 0) // Double tap check, should send nothing.
n, err = c2.Encapsulate(discard[:], -1, 0) // Double tap check, should send nothing.
if err != nil {
t.Fatal("double tap send error:", err)
} else if n > 0 {
@@ -90,13 +90,13 @@ func TestHandler(t *testing.T) {
} else if !bytes.Equal(hwaddr, expectHWAddr) {
log.Fatalf("expected to get hwaddr %x!=%x", hwaddr, expectHWAddr)
}
n, err = c1.Encapsulate(buf[:], 0)
n, err = c1.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Fatal(err)
} else if n > 0 {
t.Fatal("expected no data")
}
n, err = c2.Encapsulate(buf[:], 0)
n, err = c2.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Fatal(err)
} else if n > 0 {
arp/handler.go
+83 -14
View File
@@ -3,6 +3,7 @@ package arp
import (
"bytes"
"errors"
"log/slog"
"github.com/soypat/lneto"
"github.com/soypat/lneto/ethernet"
@@ -63,9 +64,22 @@ func (h *Handler) Reset(cfg HandlerConfig) error {
type queryResult struct {
protoaddr []byte
hwaddr []byte
dstHw []byte
querysent bool
}
func (qr *queryResult) destroy() {
*qr = queryResult{protoaddr: qr.protoaddr[:0], hwaddr: qr.hwaddr[:0]}
}
func (qr *queryResult) response() []byte {
if len(qr.hwaddr) == 0 {
return nil
}
return qr.hwaddr[:]
}
func (qr *queryResult) isInvalid() bool { return len(qr.protoaddr) == 0 }
// AbortPending drops pending queries and incoming requests.
func (h *Handler) AbortPending() {
h.pendingResponse = h.pendingResponse[:0]
@@ -81,31 +95,69 @@ func (h *Handler) QueryResult(protoAddr []byte) (hwAddr []byte, err error) {
if bytes.Equal(protoAddr, h.queries[i].protoaddr) {
if !h.queries[i].querysent {
return nil, errors.New("query not yet sent")
} else if len(h.queries[i].hwaddr) == 0 {
}
mac := h.queries[i].response()
if mac == nil {
return nil, errors.New("no response yet")
}
return h.queries[i].hwaddr, nil
return mac, nil
}
}
return nil, errors.New("query not exist or dropped")
}
func (h *Handler) StartQuery(proto []byte) error {
func (h *Handler) DiscardQuery(protoAddr []byte) error {
for i := range h.queries {
q := &h.queries[i]
if bytes.Equal(protoAddr, q.protoaddr) {
q.destroy()
return nil
}
}
return errors.New("query not found")
}
func (h *Handler) compactQueries() {
validOff := 0
for i := 0; i < len(h.queries); i++ {
if h.queries[i].isInvalid() {
h.queries[validOff] = h.queries[i]
validOff++
}
}
h.queries = h.queries[:validOff]
}
// StartQuery queues a query to perform over ARP for the protocol address `proto`.
// The user can additionally specify an dstHWAddr to write query result to on completion.
// If dstHWAddr is nil then query still occurs but no external buffer is written on query completion.
// dstHWAddr must be zeroed out (invalid MAC).
func (h *Handler) StartQuery(dstHWAddr, proto []byte) error {
if len(h.queries) == cap(h.queries) {
h.compactQueries()
if len(h.queries) == cap(h.queries) {
return errors.New("too many ongoing queries")
}
}
if len(proto) != len(h.ourProtoAddr) {
return errors.New("bad protocol address length")
} else if len(h.queries) == cap(h.queries) {
return errors.New("too many ongoing queries")
} else if dstHWAddr != nil && len(dstHWAddr) != len(h.ourHWAddr) {
return errors.New("mismatch hardware size")
} else if dstHWAddr != nil && !allZeros(dstHWAddr) {
return errors.New("write-to buffer must be zeroed out")
}
h.queries = h.queries[:len(h.queries)+1]
q := &h.queries[len(h.queries)-1]
q.hwaddr = q.hwaddr[:0]
q.querysent = false
q.protoaddr = append(q.protoaddr[:0], proto...)
*q = queryResult{
protoaddr: append(q.protoaddr[:0], proto...),
hwaddr: q.hwaddr[:0],
dstHw: dstHWAddr,
}
return nil
}
func (h *Handler) Encapsulate(eth []byte, frameOffset int) (int, error) {
b := eth[frameOffset:]
func (h *Handler) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
b := carrierData[offsetToFrame:]
n := h.expectSize()
if len(b) < n {
return 0, errShortARP
@@ -120,7 +172,7 @@ func (h *Handler) Encapsulate(eth []byte, frameOffset int) (int, error) {
copy(hwsender, h.ourHWAddr)
n := copy(b, afrm.Clip().RawData())
tgt, _ := afrm.Target()
trySetEthernetDst(eth[:frameOffset], tgt)
trySetEthernetDst(carrierData[:offsetToFrame], tgt)
return n, nil
}
for i := range h.queries {
@@ -139,7 +191,7 @@ func (h *Handler) Encapsulate(eth []byte, frameOffset int) (int, error) {
hwTarget[j] = 0
}
broadcast := ethernet.BroadcastAddr()
trySetEthernetDst(eth[:frameOffset], broadcast[:])
trySetEthernetDst(carrierData[:offsetToFrame], broadcast[:])
return n, nil
}
}
@@ -181,8 +233,16 @@ func (h *Handler) Demux(ethFrame []byte, frameOffset int) error {
case OpReply:
hwaddr, protoaddr := afrm.Sender()
for i := range h.queries {
if len(h.queries[i].hwaddr) == 0 && bytes.Equal(h.queries[i].protoaddr, protoaddr) {
h.queries[i].hwaddr = append(h.queries[i].hwaddr[:0], hwaddr...)
q := &h.queries[i]
mac := q.response()
if mac == nil && bytes.Equal(q.protoaddr, protoaddr) {
q.hwaddr = append(q.hwaddr, hwaddr...)
if q.dstHw != nil {
if !allZeros(q.dstHw) {
slog.Error("race-condition:ARP-reused-buffer")
}
copy(q.dstHw, hwaddr) // External write to user buffer.
}
return nil
}
}
@@ -198,3 +258,12 @@ func trySetEthernetDst(ethFrame []byte, dst []byte) {
copy(ethFrame[:6], dst)
}
}
func allZeros(b []byte) bool {
for i := range b {
if b[i] != 0 {
return false
}
}
return true
}
dhcpv4/client.go
+7 -7
View File
@@ -104,11 +104,11 @@ func (c *Client) Protocol() uint64 { return uint64(lneto.IPProtoUDP) }
func (c *Client) LocalPort() uint16 { return DefaultClientPort }
func (c *Client) ConnectionID() *uint64 { return &c.connID }
func (c *Client) setIP(b []byte, frameOffset int) {
if frameOffset < 28 {
return // Not an IP/UDP frame.
func (c *Client) setIP(carrierFrame []byte, offsetToIP int) {
if offsetToIP < 0 {
return // No IP layer present.
}
ifrm, _ := ipv4.NewFrame(b)
ifrm, _ := ipv4.NewFrame(carrierFrame[offsetToIP:])
ifrm.SetID((uint16(c.currentXID) ^ uint16(c.currentXID>>16)) + uint16(c.state))
if c.state > StateInit {
// Match server ToS since some routers drop DHCP requests if no ToS set apparently?
@@ -124,7 +124,7 @@ func (c *Client) setIP(b []byte, frameOffset int) {
}
}
func (c *Client) Encapsulate(carrierFrame []byte, frameOffset int) (int, error) {
func (c *Client) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
if c.isClosed() {
return 0, net.ErrClosed
} else if c.state == StateSelecting && !c.offer.valid {
@@ -134,7 +134,7 @@ func (c *Client) Encapsulate(carrierFrame []byte, frameOffset int) (int, error)
} else if c.state == StateRequesting {
return 0, nil // Currently awaiting ACK.
}
dst := carrierFrame[frameOffset:]
dst := carrierData[offsetToFrame:]
frm, err := NewFrame(dst)
if err != nil {
return 0, err
@@ -194,7 +194,7 @@ func (c *Client) Encapsulate(carrierFrame []byte, frameOffset int) (int, error)
opts[numOpts] = byte(OptEnd)
numOpts++
c.setHeader(frm)
c.setIP(carrierFrame, frameOffset)
c.setIP(carrierData, offsetToIP)
c.state = nextState
return OptionsOffset + numOpts, nil
}
dhcpv4/dhcp_test.go
+8 -8
View File
@@ -28,7 +28,7 @@ func TestClientServer(t *testing.T) {
// CLIENT DISCOVER.
assertClState(StateInit)
var buf [1024]byte
n, err := cl.Encapsulate(buf[:], 0)
n, err := cl.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Fatal(err)
} else if n == 0 {
@@ -40,7 +40,7 @@ func TestClientServer(t *testing.T) {
t.Fatal(err)
}
// SERVER REPLY OFFER
n, err = sv.Encapsulate(buf[:], 0)
n, err = sv.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Fatal(err)
} else if n == 0 {
@@ -53,7 +53,7 @@ func TestClientServer(t *testing.T) {
assertClState(StateSelecting)
// CLIENT SEND OUT REQUEST.
n, err = cl.Encapsulate(buf[:], 0)
n, err = cl.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Fatal(err)
} else if n == 0 {
@@ -66,7 +66,7 @@ func TestClientServer(t *testing.T) {
}
// SERVER REPLIES WITH ACK.
n, err = sv.Encapsulate(buf[:], 0)
n, err = sv.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Fatal(err)
} else if n == 0 {
@@ -99,13 +99,13 @@ func TestExample(t *testing.T) {
})
buf := make([]byte, 2048)
buf2 := make([]byte, len(buf))
n, err := cl.Encapsulate(buf, 0)
n, err := cl.Encapsulate(buf, -1, 0)
if err != nil {
t.Fatal(err)
} else if n <= 0 {
t.Fatal("no data sent out by client after starting request")
}
n, err = cl.Encapsulate(buf2, 0)
n, err = cl.Encapsulate(buf2, -1, 0)
if err != nil {
t.Error("client encaps double tap after discover:", err)
}
@@ -141,13 +141,13 @@ func TestExample(t *testing.T) {
t.Fatal(err)
}
n, err = cl.Encapsulate(buf[:], 0)
n, err = cl.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Fatal(err)
} else if n <= 0 {
t.Fatal("no data written from client in response to offer")
}
n, err = cl.Encapsulate(buf[:], 0)
n, err = cl.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Error("encapsulate double tap after request:", err)
} else if n > 0 {
dhcpv4/server.go
+4 -4
View File
@@ -159,9 +159,9 @@ func (sv *Server) Demux(carrierData []byte, frameOffset int) error {
return nil
}
func (sv *Server) Encapsulate(carrierData []byte, frameOffset int) (int, error) {
carrierIsIP := frameOffset >= 28
dfrm, err := NewFrame(carrierData[frameOffset:])
func (sv *Server) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
carrierIsIP := offsetToIP >= 0
dfrm, err := NewFrame(carrierData[offsetToFrame:])
optBuf := dfrm.OptionsPayload()[:]
if err != nil {
return 0, err
@@ -220,7 +220,7 @@ func (sv *Server) Encapsulate(carrierData []byte, frameOffset int) (int, error)
copy(dfrm.CHAddrAs6()[:], client.hwaddr[:])
dfrm.SetMagicCookie(MagicCookie)
if carrierIsIP {
err = internal.SetIPAddrs(carrierData, 0, sv.siaddr[:], client.addr[:])
err = internal.SetIPAddrs(carrierData[offsetToIP:], 0, sv.siaddr[:], client.addr[:])
if err != nil {
return 0, err
}
dns/client.go
+2 -2
View File
@@ -43,7 +43,7 @@ func (c *Client) StartResolve(localPort, txid uint16, cfg ResolveConfig) error {
return nil
}
func (c *Client) Encapsulate(carrierData []byte, frameOffset int) (int, error) {
func (c *Client) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
if c.isClosed() {
return 0, net.ErrClosed
} else if c.state != dnsSendQuery {
@@ -51,7 +51,7 @@ func (c *Client) Encapsulate(carrierData []byte, frameOffset int) (int, error) {
}
msg := &c.msg
frame := carrierData[frameOffset:]
frame := carrierData[offsetToFrame:]
msglen := msg.Len()
if msglen > uint16(len(frame)) {
return 0, errCalcLen
examples/bridge/main.go
+5 -5
View File
@@ -199,7 +199,7 @@ func run() (err error) {
prevState = state
clear(buf)
nwrite, err := stack.Encapsulate(buf[:], 0)
nwrite, err := stack.Encapsulate(buf[:], -1, 0)
if err != nil {
fmt.Println("ERR:ENCAPSULATE", err)
} else if nwrite > 0 {
@@ -267,10 +267,10 @@ func (s *Stack) Demux(b []byte, _ int) (err error) {
return s.link.Demux(b, 0)
}
func (s *Stack) Encapsulate(b []byte, _ int) (int, error) {
n, err := s.link.Encapsulate(b, 0)
func (s *Stack) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
n, err := s.link.Encapsulate(carrierData, offsetToIP, offsetToFrame)
if n > 0 {
iframes, errpcap := s.shark.CaptureEthernet(s.aux[:0], b[:n], 0)
iframes, errpcap := s.shark.CaptureEthernet(s.aux[:0], carrierData[:n], 0)
if errpcap != nil {
fmt.Println("OU", iframes, errpcap.Error())
} else {
@@ -426,7 +426,7 @@ func (s *Stack) StartResolveHardwareAddress6(ip netip.Addr) error {
return errors.New("unsupported or invalid IP address")
}
addr := ip.As4()
return s.arp.StartQuery(addr[:])
return s.arp.StartQuery(nil, addr[:])
}
func (s *Stack) ResultResolveHardwareAddress6(ip netip.Addr) (hw [6]byte, err error) {
examples/stack/main.go
+2 -2
View File
@@ -107,7 +107,7 @@ func main() {
}
}
nw, err := stack.ethernet.Encapsulate(buf[:], 0)
nw, err := stack.ethernet.Encapsulate(buf[:], -1, 0)
if err != nil {
lg.Error("handle", slog.String("err", err.Error()))
} else if nw > 0 {
@@ -230,7 +230,7 @@ func (stack *Stack) Recv(b []byte) error {
}
func (stack *Stack) Send(b []byte) (int, error) {
return stack.ethernet.Encapsulate(b, 0)
return stack.ethernet.Encapsulate(b, -1, 0)
}
func (stack *Stack) OpenTCPListener(port uint16) (*internet.NodeTCPListener, error) {
examples/stackbasic/main.go
+4 -4
View File
@@ -232,7 +232,7 @@ func NewEthernetTCPStack(ourMAC, gwMAC [6]byte, ip netip.AddrPort, mtu uint16, s
type handler struct {
raddr []byte
recv func([]byte, int) error
handle func([]byte, int) (int, error)
handle func([]byte, int, int) (int, error)
proto ethernet.Type
lport uint16
}
@@ -295,7 +295,7 @@ func (ls *LinkStack) HandleEth(dst []byte) (n int, err error) {
copy(efrm.DestinationHardwareAddr()[:], ls.gwmac[:]) // default set the gateway.
for i := range ls.handlers {
h := &ls.handlers[i]
n, err = h.handle(dst[:mtu], 14)
n, err = h.handle(dst[:mtu], 14, 14)
if err != nil {
ls.error("handling", slog.String("proto", ethernet.Type(h.proto).String()), slog.String("err", err.Error()))
continue
@@ -322,8 +322,8 @@ func (as *ARPStack) Recv(EtherFrame []byte, arpOff int) error {
return as.handler.Demux(EtherFrame, arpOff)
}
func (as *ARPStack) Handle(EtherFrame []byte, arpOff int) (int, error) {
n, err := as.handler.Encapsulate(EtherFrame, arpOff)
func (as *ARPStack) Handle(EtherFrame []byte, offsetToIP, arpOff int) (int, error) {
n, err := as.handler.Encapsulate(EtherFrame, offsetToIP, arpOff)
if err != nil || n == 0 {
return 0, err
}
examples/xnet/main.go
+1 -1
View File
@@ -110,7 +110,7 @@ func run() (err error) {
var frames []pcap.Frame
for {
clear(buf)
nwrite, err := stack.Encapsulate(buf[:], 0)
nwrite, err := stack.Encapsulate(buf[:], -1, 0)
if err != nil {
fmt.Println("ERR:ENCAPSULATE", err)
} else if nwrite > 0 {
internet/definitions.go
+13 -8
View File
@@ -11,18 +11,21 @@ import (
// StackNode is an abstraction of a packet exchanging protocol controller. This is the building block for all protocols,
// from Ethernet to IP to TCP, practically any protocol can be expressed as a StackNode and function completely.
type StackNode interface {
// Encapsulate writes the stack node's frame into carrierData[frameOffset:]
// Encapsulate writes the stack node's frame into carrierData[offsetToFrame:]
// along with any other frame or payload the stack node encapsulates.
// The returned integer is amount of bytes written such that carrierData[frameOffset:frameOffset+n]
// contains written data. Data inside carrierData[:frameOffset] usually contains data necessary for
// The returned integer is amount of bytes written such that carrierData[offsetToFrame:offsetToFrame+n]
// contains written data. Data inside carrierData[:offsetToFrame] usually contains data necessary for
// a StackNode to correctly emit valid frame data: such is the case for TCP packets which require IP
// frame data for checksum calculation. Thus StackNodes must provide fields in their own frame
// required by sub-stacknodes for correct encapsulation; in the case of IPv4/6 this means including fields
// used in pseudo-header checksum like local IP (see [ipv4.CRCWriteUDPPseudo]).
//
// offsetToIP is the offset to the IP frame, if present, else its value should be -1.
// The relation offsetToIP<=offsetToFrame should always hold.
//
// When [net.ErrClosed] is returned the StackNode should be discarded and any written data passed up normally.
// Errors returned by Encapsulate are "extraordinary" and should not be returned unless the StackNode is receiving invalid carrierData/frameOffset.
Encapsulate(carrierData []byte, frameOffset int) (int, error)
Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error)
// Demux reads from the argument buffer where frameOffset is the offset of this StackNode's frame first byte.
// The stack node then dispatches(demuxes) the encapsulated frames to its corresponding sub-stack-node(s).
Demux(carrierData []byte, frameOffset int) error
@@ -38,10 +41,12 @@ type node struct {
currConnID uint64
connID *uint64
demux func([]byte, int) error
encapsulate func([]byte, int) (int, error)
encapsulate func([]byte, int, int) (int, error)
proto uint16
port uint16
remoteAddr []byte
// remoteAddr will be set on active(outbound) port connections
// that require an ARP to set the remoteAddr beforehand.
remoteAddr []byte
}
type handlers struct {
@@ -166,13 +171,13 @@ func (h *handlers) demuxByPort(buf []byte, offset int, port uint16) (*node, erro
// encapsulateAny finds a node suitable to write and encapsulates the package.
// If no data is sent it returns the last error encountered.
func (h *handlers) encapsulateAny(buf []byte, offset int) (_ *node, n int, err error) {
func (h *handlers) encapsulateAny(buf []byte, offsetIP, offsetThisFrame int) (_ *node, n int, err error) {
for i := range h.nodes {
node := &h.nodes[i]
if node.IsInvalid() {
continue
}
n, err = node.encapsulate(buf, offset)
n, err = node.encapsulate(buf, offsetIP, offsetThisFrame)
if h.tryHandleError(node, err) {
err = nil // CLOSE error handled gracefully by deleting node.
}
internet/node-tcplistener.go
+2 -2
View File
@@ -94,7 +94,7 @@ func (listener *NodeTCPListener) TryAccept() (*tcp.Conn, error) {
}
// Encapsulate implements [StackNode].
func (listener *NodeTCPListener) Encapsulate(carrierData []byte, tcpFrameOffset int) (int, error) {
func (listener *NodeTCPListener) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
if listener.isClosed() {
return 0, net.ErrClosed
}
@@ -102,7 +102,7 @@ func (listener *NodeTCPListener) Encapsulate(carrierData []byte, tcpFrameOffset
if conn == nil {
continue
}
n, err := conn.Encapsulate(carrierData, tcpFrameOffset)
n, err := conn.Encapsulate(carrierData, offsetToIP, offsetToFrame)
if err != nil {
err = listener.maintainConn(listener.accepted, i, err)
}
internet/stack-ethernet.go
+8 -3
View File
@@ -92,9 +92,9 @@ DROP:
return lneto.ErrPacketDrop
}
func (ls *StackEthernet) Encapsulate(carrierData []byte, frameOffset int) (n int, err error) {
func (ls *StackEthernet) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (n int, err error) {
mtu := ls.mtu
dst := carrierData[frameOffset:]
dst := carrierData[offsetToFrame:]
if len(dst) < int(mtu) {
return 0, io.ErrShortBuffer
}
@@ -104,7 +104,12 @@ func (ls *StackEthernet) Encapsulate(carrierData []byte, frameOffset int) (n int
}
*efrm.DestinationHardwareAddr() = ls.gwmac
var h *node
h, n, err = ls.handlers.encapsulateAny(dst[:mtu], 14)
// Children (IP/ARP) start at offset 14 (after ethernet header).
// For IP: offsetToIP=14, offsetToFrame=14
// For ARP: offsetToIP=-1, offsetToFrame=14 (but ARP ignores offsetToIP)
// Clip carrierData to MTU to prevent writes beyond MTU limit.
mtuLimit := offsetToFrame + int(mtu)
h, n, err = ls.handlers.encapsulateAny(carrierData[:mtuLimit], offsetToFrame+14, offsetToFrame+14)
if n == 0 {
return n, err
}
internet/stack-ip.go
+5 -3
View File
@@ -140,8 +140,8 @@ func (sb *StackIP) Demux(carrierData []byte, offset int) error {
return err
}
func (sb *StackIP) Encapsulate(carrierData []byte, frameOffset int) (int, error) {
frame := carrierData[frameOffset:]
func (sb *StackIP) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
frame := carrierData[offsetToFrame:]
if len(frame) < 256 {
return 0, io.ErrShortBuffer
}
@@ -158,7 +158,9 @@ func (sb *StackIP) Encapsulate(carrierData []byte, frameOffset int) (int, error)
ifrm.SetTTL(64)
*ifrm.SourceAddr() = sb.ip
sb.ipID = id
node, n, err := sb.handlers.encapsulateAny(frame, headerlen)
// Children (TCP/UDP) start at offset headerlen (20 bytes after IP header start).
// offsetToIP is 0 relative to this slice (frame), children's frame starts at headerlen.
node, n, err := sb.handlers.encapsulateAny(carrierData, offsetToFrame, offsetToFrame+headerlen)
if n == 0 {
return n, err
}
internet/stack-ports.go
+3 -3
View File
@@ -46,11 +46,11 @@ func (ps *StackPorts) Protocol() uint64 { return uint64(ps.protocol) }
func (ps *StackPorts) ConnectionID() *uint64 { return &ps.connID }
func (ps *StackPorts) Encapsulate(b []byte, offset int) (n int, err error) {
if int(ps.dstPortOff)+offset+2 > len(b) {
func (ps *StackPorts) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (n int, err error) {
if int(ps.dstPortOff)+offsetToFrame+2 > len(carrierData) {
return 0, io.ErrShortBuffer
}
_, n, err = ps.handlers.encapsulateAny(b, offset)
_, n, err = ps.handlers.encapsulateAny(carrierData, offsetToIP, offsetToFrame)
return n, err
}
internet/stack-udpport.go
+6 -5
View File
@@ -61,24 +61,25 @@ func (sudp *StackUDPPort) Demux(carrierData []byte, frameOffset int) error {
return err
}
func (sudp *StackUDPPort) Encapsulate(carrierData []byte, frameOffset int) (int, error) {
func (sudp *StackUDPPort) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
if sudp.h.IsInvalid() {
sudp.h.destroy()
return 0, net.ErrClosed
}
ufrm, err := udp.NewFrame(carrierData[frameOffset:])
ufrm, err := udp.NewFrame(carrierData[offsetToFrame:])
if err != nil {
return 0, err
}
ufrm.SetSourcePort(sudp.h.port)
ufrm.SetDestinationPort(sudp.rmport)
if len(sudp.raddr) > 0 && frameOffset >= 20 {
err = internal.SetIPAddrs(carrierData, 0, nil, sudp.raddr)
if len(sudp.raddr) > 0 && offsetToIP >= 0 {
err = internal.SetIPAddrs(carrierData[offsetToIP:], 0, nil, sudp.raddr)
if err != nil {
return 0, err
}
}
n, err := sudp.h.encapsulate(carrierData, frameOffset+8)
// Child payload starts 8 bytes after UDP header start.
n, err := sudp.h.encapsulate(carrierData, offsetToIP, offsetToFrame+8)
if n == 0 {
if err != nil {
slog.Error("stackudp:encapsulate", slog.String("err", err.Error()))
internet/stackbasic_test.go
+1 -1
View File
@@ -44,7 +44,7 @@ func TestBasicStack2(t *testing.T) {
func expectExchange(t *testing.T, from, to *StackIP, buf []byte) {
t.Helper()
n, err := from.Encapsulate(buf, 0)
n, err := from.Encapsulate(buf, -1, 0)
if err != nil {
t.Error("expectExchange:encapsulate:", err)
} else if n == 0 {
ntp/client.go
+2 -2
View File
@@ -50,11 +50,11 @@ func (c *Client) ConnectionID() *uint64 {
return &c.connID
}
func (c *Client) Encapsulate(carrierData []byte, frameOffset int) (int, error) {
func (c *Client) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
if c.IsDone() {
return 0, nil
}
payload := carrierData[frameOffset:]
payload := carrierData[offsetToFrame:]
frm, err := NewFrame(payload)
if err != nil {
return 0, err
tcp/conn.go
+8 -4
View File
@@ -278,23 +278,27 @@ func (conn *Conn) Demux(buf []byte, off int) (err error) {
return nil
}
func (conn *Conn) Encapsulate(buf []byte, off int) (n int, err error) {
func (conn *Conn) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (n int, err error) {
conn.mu.Lock()
defer conn.mu.Unlock()
if len(conn.remoteAddr) == 0 {
return 0, errNoRemoteAddr
}
raddr, _, _, _, err := internal.GetIPAddr(buf[:off])
if offsetToIP < 0 {
return 0, errNoRemoteAddr // No IP layer present.
}
ipFrame := carrierData[offsetToIP:offsetToFrame]
raddr, _, _, _, err := internal.GetIPAddr(ipFrame)
if err != nil {
return 0, err
} else if len(raddr) != len(conn.remoteAddr) {
return 0, errMismatchedIPVersion
}
n, err = conn.h.Send(buf[off:])
n, err = conn.h.Send(carrierData[offsetToFrame:])
if err != nil {
return 0, err
}
err = internal.SetIPAddrs(buf[:off], conn.ipID, nil, conn.remoteAddr)
err = internal.SetIPAddrs(ipFrame, conn.ipID, nil, conn.remoteAddr)
if err != nil {
return 0, err
}
x/xnet/stack-async.go
+3 -3
View File
@@ -73,11 +73,11 @@ func (s *StackAsync) Demux(carrierData []byte, etherOff int) error {
return s.link.Demux(carrierData, etherOff)
}
func (s *StackAsync) Encapsulate(carrierData []byte, etherOff int) (int, error) {
func (s *StackAsync) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
s.mu.Lock()
defer s.mu.Unlock()
n, err := s.link.Encapsulate(carrierData, etherOff)
n, err := s.link.Encapsulate(carrierData, offsetToIP, offsetToFrame)
s.totalsent += uint64(n)
return n, err
}
@@ -376,7 +376,7 @@ func (s *StackAsync) StartResolveHardwareAddress6(ip netip.Addr) error {
return errors.New("unsupported or invalid IP address")
}
addr := ip.As4()
return s.arp.StartQuery(addr[:])
return s.arp.StartQuery(nil, addr[:])
}
// ResultResolveHardwareAddress6
x/xnet/xnet_test.go
+1 -1
View File
@@ -322,7 +322,7 @@ func (tst *tester) TCPExchange(expect tcpExpectExchange, stack1, stack2 *StackAs
default:
panic("OOB")
}
n, err := src.Encapsulate(buf[:], 0)
n, err := src.Encapsulate(buf[:], -1, 0)
if err != nil {
t.Fatal(err)
} else if n == 0 {