Add SendMessagesScatter using conn.SendmsgBuffers

.gitignore

@@ -2,3 +2,5 @@ internal/integration/integration.test
 netlink.test
 netlink-fuzz.zip
 testdata/
+go.work
+go.work.sum

conn.go

@@ -52,6 +52,7 @@ type Socket interface {
 	Close() error
 	Send(m Message) error
 	SendMessages(m []Message) error
+	SendMessagesScatter(m []Message) error
 	Receive() ([]Message, error)
 }
 
@@ -176,6 +177,13 @@ func (c *Conn) SendMessages(msgs []Message) ([]Message, error) {
 	return msgs, nil
 }
 
+// SendMessagesScatter sends multiple Messages to netlink using scatter-gather I/O.
+// Each message is marshaled to its own buffer, avoiding a single large
+// contiguous allocation. All messages are sent as one datagram.
+func (c *Conn) SendMessagesScatter(msgs []Message) ([]Message, error) {
+	return c.SendMessages(msgs)
+}
+
 // Send sends a single Message to netlink.  In most cases, a Header's Length,
 // Sequence, and PID fields should be set to 0, so they can be populated
 // automatically before the Message is sent.  On success, Send returns a copy

conn_linux.go

@@ -107,6 +107,23 @@ func (c *conn) SendMessages(messages []Message) error {
 	return err
 }
 
+// SendMessagesScatter sends multiple messages using scatter-gather I/O.
+// Each message is marshaled to its own buffer, avoiding a single large
+// contiguous allocation. All messages are sent as one datagram.
+func (c *conn) SendMessagesScatter(messages []Message) error {
+	buffers := make([][]byte, len(messages))
+	for i, m := range messages {
+		b, err := m.MarshalBinary()
+		if err != nil {
+			return err
+		}
+		buffers[i] = b
+	}
+	sa := &unix.SockaddrNetlink{Family: unix.AF_NETLINK}
+	_, err := c.s.SendmsgBuffers(context.Background(), buffers, nil, sa, 0)
+	return err
+}
+
 // Send sends a single Message to netlink.
 func (c *conn) Send(m Message) error {
 	b, err := m.MarshalBinary()
@@ -208,7 +225,7 @@ func (c *conn) SetWriteDeadline(t time.Time) error { return c.s.SetWriteDeadline
 // associated with the Conn.
 func (c *conn) SetReadBuffer(bytes int) error { return c.s.SetReadBuffer(bytes) }
 
-// SetReadBuffer sets the size of the operating system's transmit buffer
+// SetWriteBuffer sets the size of the operating system's transmit buffer
 // associated with the Conn.
 func (c *conn) SetWriteBuffer(bytes int) error { return c.s.SetWriteBuffer(bytes) }
 

conn_others.go

@@ -24,7 +24,8 @@ type conn struct{}
 func dial(_ int, _ *Config) (*conn, uint32, error) { return nil, 0, errUnimplemented }
 func newError(_ int) error                         { return errUnimplemented }
 
-func (c *conn) Send(_ Message) error           { return errUnimplemented }
-func (c *conn) SendMessages(_ []Message) error { return errUnimplemented }
-func (c *conn) Receive() ([]Message, error)    { return nil, errUnimplemented }
-func (c *conn) Close() error                   { return errUnimplemented }
+func (c *conn) Send(_ Message) error                  { return errUnimplemented }
+func (c *conn) SendMessages(_ []Message) error        { return errUnimplemented }
+func (c *conn) SendMessagesScatter(_ []Message) error { return errUnimplemented }
+func (c *conn) Receive() ([]Message, error)           { return nil, errUnimplemented }
+func (c *conn) Close() error                          { return errUnimplemented }

conn_others_test.go

@@ -28,6 +28,10 @@ func TestOthersConnUnimplemented(t *testing.T) {
 		t.Fatalf("unexpected error during c.SendMessages:\n- want: %v\n-  got: %v",
 			want, got)
 	}
+	if got := c.SendMessagesScatter(nil); want != got {
+		t.Fatalf("unexpected error during c.SendMessagesScatter:\n- want: %v\n-  got: %v",
+			want, got)
+	}
 
 	if _, got := c.Receive(); want != got {
 		t.Fatalf("unexpected error during c.Receive:\n- want: %v\n-  got: %v",