correct netdever Accept() prototype

According to man page accept(2), accept returns new client sockfd and
remote peer ip:port.  This patch corrects the Accept() prototype in the
netdever interface to not take in an ip:port arg, but rather return an
ip:port for remote peer.

Tested with examples/net/tcpecho on wioterminal and nano-rp2040.  Here's
a run with wioterminal:

SERVER
============
sfeldma@nuc:~/work/drivers$ tinygo flash -monitor -target wioterminal -size short -stack-size=8kb ./examples/net/tcpecho
code    data     bss |   flash     ram
110876    2552   11212 |  113428   13764
Connected to /dev/ttyACM2. Press Ctrl-C to exit.

Realtek rtl8720dn Wifi network device driver (rtl8720dn)

Driver version           : 0.0.1
RTL8720 firmware version : 2.1.2
MAC address              : 2c:f7:f1:1c:9b:2f

Connecting to Wifi SSID 'test'...CONNECTED

DHCP-assigned IP         : 10.0.0.140
DHCP-assigned subnet     : 255.255.255.0
DHCP-assigned gateway    : 10.0.0.1

Starting TCP server listening on :8080
Client 10.0.0.190:50000 connected
Client 10.0.0.190:50000 closed

CLIENT
=============
nc -p 50000 10.0.0.140 8080

espat/espat.go

@@ -218,8 +218,8 @@ func (d *Device) Listen(sockfd int, backlog int) error {
 	return nil
 }
 
-func (d *Device) Accept(sockfd int, ip netip.AddrPort) (int, error) {
+func (d *Device) Accept(sockfd int) (int, netip.AddrPort, error) {
-	return -1, netdev.ErrNotSupported
+	return -1, netip.AddrPort{}, netdev.ErrNotSupported
 }
 
 func (d *Device) sendChunk(sockfd int, buf []byte, deadline time.Time) (int, error) {

examples/net/tcpecho/main.go

@@ -30,16 +30,18 @@ var (
 var buf [1024]byte
 
 func echo(conn net.Conn) {
+	println("Client", conn.RemoteAddr(), "connected")
 	defer conn.Close()
 	_, err := io.CopyBuffer(conn, conn, buf[:])
 	if err != nil && err != io.EOF {
 		log.Fatal(err.Error())
 	}
+	println("Client", conn.RemoteAddr(), "closed")
 }
 
 func main() {
 
-	time.Sleep(time.Second)
+	time.Sleep(2 * time.Second)
 
 	link, _ := probe.Probe()
 
@@ -51,6 +53,7 @@ func main() {
 		log.Fatal(err)
 	}
 
+	println("Starting TCP server listening on", port)
 	l, err := net.Listen("tcp", port)
 	if err != nil {
 		log.Fatal(err.Error())

netdev/netdev.go

@@ -82,7 +82,7 @@ type Netdever interface {
 	Bind(sockfd int, ip netip.AddrPort) error
 	Connect(sockfd int, host string, ip netip.AddrPort) error
 	Listen(sockfd int, backlog int) error
-	Accept(sockfd int, ip netip.AddrPort) (int, error)
+	Accept(sockfd int) (int, netip.AddrPort, error)
 	Send(sockfd int, buf []byte, flags int, deadline time.Time) (int, error)
 	Recv(sockfd int, buf []byte, flags int, deadline time.Time) (int, error)
 	Close(sockfd int) error

rtl8720dn/rtl8720dn.go

@@ -437,6 +437,12 @@ func ipToName(ip netip.AddrPort) []byte {
 	return name
 }
 
+func nameToIp(name []byte) netip.AddrPort {
+	port := uint16(name[2])<<8 | uint16(name[3])
+	addr, _ := netip.AddrFromSlice(name[4:8])
+	return netip.AddrPortFrom(addr, port)
+}
+
 func (r *rtl8720dn) Bind(sockfd int, ip netip.AddrPort) error {
 
 	if debugging(debugNetdev) {
@@ -534,10 +540,10 @@ func (r *rtl8720dn) Listen(sockfd int, backlog int) error {
 	return nil
 }
 
-func (r *rtl8720dn) Accept(sockfd int, ip netip.AddrPort) (int, error) {
+func (r *rtl8720dn) Accept(sockfd int) (int, netip.AddrPort, error) {
 
 	if debugging(debugNetdev) {
-		fmt.Printf("[Accept] sockfd: %d, peer: %s\r\n", sockfd, ip)
+		fmt.Printf("[Accept] sockfd: %d\r\n", sockfd)
 	}
 
 	r.mu.Lock()
@@ -546,12 +552,12 @@ func (r *rtl8720dn) Accept(sockfd int, ip netip.AddrPort) (int, error) {
 	var newSock int32
 	var lsock = sock(sockfd)
 	var socket = r.sockets[lsock]
-	var name = ipToName(ip)
+	var name = ipToName(netip.AddrPort{})
 
 	switch socket.protocol {
 	case netdev.IPPROTO_TCP:
 	default:
-		return -1, netdev.ErrProtocolNotSupported
+		return -1, netip.AddrPort{}, netdev.ErrProtocolNotSupported
 	}
 
 	for {
@@ -570,6 +576,14 @@ func (r *rtl8720dn) Accept(sockfd int, ip netip.AddrPort) (int, error) {
 			continue
 		}
 
+		// Get remote peer ip:port
+		namelen = uint32(len(name))
+		result := r.rpc_lwip_getpeername(int32(newSock), name, &namelen)
+		if result == -1 {
+			return -1, netip.AddrPort{}, fmt.Errorf("Getpeername failed")
+		}
+		raddr := nameToIp(name)
+
 		// If we've already seen this socket, we can re-use
 		// the socket and return it.  But, only if the socket
 		// is closed.  If it's not closed, we'll just come back
@@ -582,12 +596,12 @@ func (r *rtl8720dn) Accept(sockfd int, ip netip.AddrPort) (int, error) {
 				continue
 			}
 			// Reuse client socket
-			return int(newSock), nil
+			return int(newSock), raddr, nil
 		}
 
 		// Create new socket for client and return fd
 		r.sockets[sock(newSock)] = newSocket(socket.protocol)
-		return int(newSock), nil
+		return int(newSock), raddr, nil
 	}
 }
 

wifinina/wifinina.go

@@ -676,10 +676,10 @@ func (w *wifinina) Listen(sockfd int, backlog int) error {
 	return nil
 }
 
-func (w *wifinina) Accept(sockfd int, ip netip.AddrPort) (int, error) {
+func (w *wifinina) Accept(sockfd int) (int, netip.AddrPort, error) {
 
 	if debugging(debugNetdev) {
-		fmt.Printf("[Accept] sockfd: %d, peer: %s\r\n", sockfd, ip)
+		fmt.Printf("[Accept] sockfd: %d\r\n", sockfd)
 	}
 
 	w.mu.Lock()
@@ -692,7 +692,7 @@ func (w *wifinina) Accept(sockfd int, ip netip.AddrPort) (int, error) {
 	switch socket.protocol {
 	case netdev.IPPROTO_TCP:
 	default:
-		return -1, netdev.ErrProtocolNotSupported
+		return -1, netip.AddrPort{}, netdev.ErrProtocolNotSupported
 	}
 
 	for {
@@ -704,7 +704,7 @@ func (w *wifinina) Accept(sockfd int, ip netip.AddrPort) (int, error) {
 
 		// Check if we've faulted
 		if w.fault != nil {
-			return -1, w.fault
+			return -1, netip.AddrPort{}, w.fault
 		}
 
 		// TODO: BUG: Currently, a sock that is 100% busy will always be
@@ -720,6 +720,8 @@ func (w *wifinina) Accept(sockfd int, ip netip.AddrPort) (int, error) {
 			continue
 		}
 
+		raddr := w.getRemoteData(client)
+
 		// If we've already seen this socket, we can reuse
 		// the socket and return it.  But, only if the socket
 		// is closed.  If it's not closed, we'll just come back
@@ -732,12 +734,12 @@ func (w *wifinina) Accept(sockfd int, ip netip.AddrPort) (int, error) {
 				continue
 			}
 			// Reuse client socket
-			return int(client), nil
+			return int(client), raddr, nil
 		}
 
 		// Create new socket for client and return fd
 		w.sockets[client] = newSocket(socket.protocol)
-		return int(client), nil
+		return int(client), raddr, nil
 	}
 }
 
@@ -1123,6 +1125,23 @@ func (w *wifinina) accept(s sock) sock {
 	return newsock
 }
 
+func (w *wifinina) getRemoteData(s sock) netip.AddrPort {
+
+	if debugging(debugCmd) {
+		fmt.Printf("    [cmdGetRemoteData] sock: %d\r\n", s)
+	}
+
+	sl := make([]string, 2)
+	l := w.reqRspStr1(cmdGetRemoteData, uint8(s), sl)
+	if l != 2 {
+		w.faultf("getRemoteData wanted l=2, got l=%d", l)
+		return netip.AddrPort{}
+	}
+	ip, _ := netip.AddrFromSlice([]byte(sl[0])[:4])
+	port := binary.BigEndian.Uint16([]byte(sl[1]))
+	return netip.AddrPortFrom(ip, port)
+}
+
 // insertDataBuf adds data to the buffer used for sending UDP data
 func (w *wifinina) insertDataBuf(sock sock, buf []byte) bool {