From a476b1fa0732501b02bd995169654d337fb7b09a Mon Sep 17 00:00:00 2001
From: JackDoan <me@jackdoan.com>
Date: Tue, 28 Apr 2026 10:56:57 -0500
Subject: [PATCH] Remove WriteFromSelf

---
 inside.go                     |  4 ++--
 overlay/overlaytest/noop.go   |  4 ----
 overlay/tio/tio.go            | 13 ++-----------
 overlay/tio/tio_poll_linux.go |  4 ----
 overlay/tun_android.go        |  4 ----
 overlay/tun_darwin.go         |  4 ----
 overlay/tun_disabled.go       |  4 ----
 overlay/tun_freebsd.go        |  4 ----
 overlay/tun_ios.go            |  4 ----
 overlay/tun_netbsd.go         |  4 ----
 overlay/tun_openbsd.go        |  4 ----
 overlay/tun_tester.go         |  4 ----
 overlay/tun_windows.go        |  4 ----
 overlay/user.go               |  4 +---
 14 files changed, 5 insertions(+), 60 deletions(-)

diff --git a/inside.go b/inside.go
index 2b0ad70c..e528e892 100644
--- a/inside.go
+++ b/inside.go
@@ -38,7 +38,7 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 		// routes packets from the Nebula addr to the Nebula addr through the Nebula
 		// TUN device.
 		if immediatelyForwardToSelf {
-			_, err := f.readers[q].WriteFromSelf(packet)
+			_, err := f.readers[q].Write(packet)
 			if err != nil {
 				f.l.Error("Failed to forward to tun", "error", err)
 			}
@@ -157,7 +157,7 @@ func (f *Interface) rejectInside(packet []byte, out []byte, q int) {
 		return
 	}
 
-	_, err := f.readers[q].WriteFromSelf(out)
+	_, err := f.readers[q].Write(out)
 	if err != nil {
 		f.l.Error("Failed to write to tun", "error", err)
 	}
diff --git a/overlay/overlaytest/noop.go b/overlay/overlaytest/noop.go
index 99ef4d15..10886511 100644
--- a/overlay/overlaytest/noop.go
+++ b/overlay/overlaytest/noop.go
@@ -39,10 +39,6 @@ func (NoopTun) Write([]byte) (int, error) {
 	return 0, nil
 }
 
-func (NoopTun) WriteFromSelf(p []byte) (int, error) {
-	return 0, nil
-}
-
 func (NoopTun) SupportsMultiqueue() bool {
 	return false
 }
diff --git a/overlay/tio/tio.go b/overlay/tio/tio.go
index 792083ab..94240d06 100644
--- a/overlay/tio/tio.go
+++ b/overlay/tio/tio.go
@@ -23,21 +23,12 @@ type Queue interface {
 	// Read returns one or more packets. The returned slices are borrowed
 	// from the Queue's internal buffer and are only valid until the next
 	// Read or Close on this Queue - callers must encrypt or copy each
-	// slice before the next call. Not safe for concurrent Reads; exactly
-	// one goroutine per Queue reads.
+	// slice before the next call. Not safe for concurrent Reads.
 	Read() ([][]byte, error)
 
 	// Write emits a single packet on the plaintext (outside→inside)
-	// delivery path. May run concurrently with WriteFromSelf on the same
-	// Queue, but not with itself.
+	// delivery path. Not safe for concurrent Writes.
 	Write(p []byte) (int, error)
-
-	// WriteFromSelf writes a single packet that originated from the inside
-	// path (reject replies or self-forward) using scratch state distinct
-	// from Write, so it can run concurrently with Write on the same Queue
-	// without a data race. On backends without a shared-scratch Write, a
-	// trivial delegation to Write is acceptable.
-	WriteFromSelf(p []byte) (int, error)
 }
 
 // GSOWriter is implemented by Queues that can emit a TCP TSO superpacket
diff --git a/overlay/tio/tio_poll_linux.go b/overlay/tio/tio_poll_linux.go
index 17fb73de..21ae1336 100644
--- a/overlay/tio/tio_poll_linux.go
+++ b/overlay/tio/tio_poll_linux.go
@@ -162,7 +162,3 @@ func (t *Poll) Close() error {
 
 	return err
 }
-
-func (t *Poll) WriteFromSelf(p []byte) (int, error) {
-	return t.Write(p)
-}
diff --git a/overlay/tun_android.go b/overlay/tun_android.go
index b68dfcd5..c2342556 100644
--- a/overlay/tun_android.go
+++ b/overlay/tun_android.go
@@ -43,10 +43,6 @@ func (t *tun) Write(p []byte) (int, error) {
 	return t.rwc.Write(p)
 }
 
-func (t *tun) WriteFromSelf(p []byte) (int, error) {
-	return t.rwc.Write(p)
-}
-
 func (t *tun) Close() error {
 	return t.rwc.Close()
 }
diff --git a/overlay/tun_darwin.go b/overlay/tun_darwin.go
index 9a4b70e6..b4254b05 100644
--- a/overlay/tun_darwin.go
+++ b/overlay/tun_darwin.go
@@ -525,10 +525,6 @@ func (t *tun) Read() ([][]byte, error) {
 	return t.batchRet[:], nil
 }
 
-func (t *tun) WriteFromSelf(p []byte) (int, error) {
-	return t.Write(p)
-}
-
 // Write is only valid for single threaded use
 func (t *tun) Write(from []byte) (int, error) {
 	buf := t.out
diff --git a/overlay/tun_disabled.go b/overlay/tun_disabled.go
index 5daa4797..12f8b883 100644
--- a/overlay/tun_disabled.go
+++ b/overlay/tun_disabled.go
@@ -108,10 +108,6 @@ func (t *disabledTun) Write(b []byte) (int, error) {
 	return len(b), nil
 }
 
-func (t *disabledTun) WriteFromSelf(b []byte) (int, error) {
-	return t.Write(b)
-}
-
 func (t *disabledTun) SupportsMultiqueue() bool {
 	return true
 }
diff --git a/overlay/tun_freebsd.go b/overlay/tun_freebsd.go
index 980c3efb..90beb557 100644
--- a/overlay/tun_freebsd.go
+++ b/overlay/tun_freebsd.go
@@ -168,10 +168,6 @@ func (t *tun) Read() ([][]byte, error) {
 	return t.batchRet[:], nil
 }
 
-func (t *tun) WriteFromSelf(p []byte) (int, error) {
-	return t.Write(p)
-}
-
 func (t *tun) readOne(to []byte) (int, error) {
 	// first 4 bytes is protocol family, in network byte order
 	var head [4]byte
diff --git a/overlay/tun_ios.go b/overlay/tun_ios.go
index 65dc0edc..44607eb2 100644
--- a/overlay/tun_ios.go
+++ b/overlay/tun_ios.go
@@ -45,10 +45,6 @@ func (t *tun) Write(p []byte) (int, error) {
 	return t.rwc.Write(p)
 }
 
-func (t *tun) WriteFromSelf(p []byte) (int, error) {
-	return t.rwc.Write(p)
-}
-
 func (t *tun) Close() error {
 	return t.rwc.Close()
 }
diff --git a/overlay/tun_netbsd.go b/overlay/tun_netbsd.go
index 8275b754..4a0f502f 100644
--- a/overlay/tun_netbsd.go
+++ b/overlay/tun_netbsd.go
@@ -80,10 +80,6 @@ func (t *tun) Read() ([][]byte, error) {
 	return t.batchRet[:], nil
 }
 
-func (t *tun) WriteFromSelf(p []byte) (int, error) {
-	return t.Write(p)
-}
-
 func (t *tun) Readers() []tio.Queue {
 	return []tio.Queue{t}
 }
diff --git a/overlay/tun_openbsd.go b/overlay/tun_openbsd.go
index 8c16b977..2369a7c2 100644
--- a/overlay/tun_openbsd.go
+++ b/overlay/tun_openbsd.go
@@ -73,10 +73,6 @@ func (t *tun) Read() ([][]byte, error) {
 	return t.batchRet[:], nil
 }
 
-func (t *tun) WriteFromSelf(p []byte) (int, error) {
-	return t.Write(p)
-}
-
 var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
 
 func newTunFromFd(_ *config.C, _ *slog.Logger, _ int, _ []netip.Prefix) (*tun, error) {
diff --git a/overlay/tun_tester.go b/overlay/tun_tester.go
index 22bc9f5c..95d13b39 100644
--- a/overlay/tun_tester.go
+++ b/overlay/tun_tester.go
@@ -128,10 +128,6 @@ func (t *TestTun) Write(b []byte) (n int, err error) {
 	return len(b), nil
 }
 
-func (t *TestTun) WriteFromSelf(b []byte) (int, error) {
-	return t.Write(b)
-}
-
 func (t *TestTun) Close() error {
 	if t.closed.CompareAndSwap(false, true) {
 		close(t.rxPackets)
diff --git a/overlay/tun_windows.go b/overlay/tun_windows.go
index c99d259f..80cb7fa0 100644
--- a/overlay/tun_windows.go
+++ b/overlay/tun_windows.go
@@ -50,10 +50,6 @@ func (t *winTun) Read() ([][]byte, error) {
 	return t.batchRet[:], nil
 }
 
-func (t *winTun) WriteFromSelf(p []byte) (int, error) {
-	return t.Write(p)
-}
-
 func newTunFromFd(_ *config.C, _ *slog.Logger, _ int, _ []netip.Prefix) (Device, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported in Windows")
 }
diff --git a/overlay/user.go b/overlay/user.go
index fcb1ee51..be6b327b 100644
--- a/overlay/user.go
+++ b/overlay/user.go
@@ -88,9 +88,7 @@ func (d *UserDevice) Pipe() (*io.PipeReader, *io.PipeWriter) {
 func (d *UserDevice) Write(p []byte) (n int, err error) {
 	return d.inboundWriter.Write(p)
 }
-func (d *UserDevice) WriteFromSelf(p []byte) (n int, err error) {
-	return d.Write(p)
-}
+
 func (d *UserDevice) Close() error {
 	d.inboundWriter.Close()
 	d.outboundWriter.Close()