Move examples/ping-pong into two directories

Example is now directly Go runnable

examples/ping-pong/README.md

@@ -9,21 +9,17 @@ In this example, there are 2 types of peers: **ping** and **pong**.
 
 ## Instruction
 
-### Build ping and pong
-
-```sh
-make
-```
+### Run ping and pong
 
 ### Run pong
 
 ```sh
-./pong
+go run github.com/pion/sctp/examples/ping-pong/pong@latest
 ```
 
 
 ### Run ping
 
 ```sh
-./ping
-```
+go run github.com/pion/sctp/examples/ping-pong/ping@latest
+```

examples/ping-pong/ping.go → examples/ping-pong/ping/main.go

@@ -10,6 +10,7 @@ import (
 	"fmt"
 	"log"
 	"net"
+	"time"
 
 	"github.com/pion/logging"
 	"github.com/pion/sctp"
@@ -22,7 +23,7 @@ func main() {
 	}
 	defer func() {
 		if closeErr := conn.Close(); closeErr != nil {
-			panic(err)
+			log.Panic(err)
 		}
 	}()
 	fmt.Println("dialed udp ponger")
@@ -37,7 +38,7 @@ func main() {
 	}
 	defer func() {
 		if closeErr := a.Close(); closeErr != nil {
-			panic(err)
+			log.Panic(err)
 		}
 	}()
 	fmt.Println("created a client")
@@ -48,7 +49,7 @@ func main() {
 	}
 	defer func() {
 		if closeErr := stream.Close(); closeErr != nil {
-			panic(err)
+			log.Panic(err)
 		}
 	}()
 	fmt.Println("opened a stream")
@@ -66,6 +67,7 @@ func main() {
 			}
 			fmt.Println("sent:", pingMsg)
 			pingSeqNum++
+			time.Sleep(time.Second)
 		}
 	}()
 

examples/ping-pong/pong/conn.go

@@ -0,0 +1,76 @@
+// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+// Package main implements a simple ping-pong example
+package main
+
+import (
+	"net"
+	"sync"
+	"time"
+)
+
+// Reference: https://github.com/pion/sctp/blob/master/association_test.go
+// Since UDP is connectionless, as a server, it doesn't know how to reply
+// simply using the `Write` method. So, to make it work, `disconnectedPacketConn`
+// will infer the last packet that it reads as the reply address for `Write`
+
+type disconnectedPacketConn struct { // nolint: unused
+	mu    sync.RWMutex
+	rAddr net.Addr
+	pConn net.PacketConn
+}
+
+// Read
+func (c *disconnectedPacketConn) Read(p []byte) (int, error) { //nolint:unused
+	i, rAddr, err := c.pConn.ReadFrom(p)
+	if err != nil {
+		return 0, err
+	}
+
+	c.mu.Lock()
+	c.rAddr = rAddr
+	c.mu.Unlock()
+
+	return i, err
+}
+
+// Write writes len(p) bytes from p to the DTLS connection
+func (c *disconnectedPacketConn) Write(p []byte) (n int, err error) { //nolint:unused
+	return c.pConn.WriteTo(p, c.RemoteAddr())
+}
+
+// Close closes the conn and releases any Read calls
+func (c *disconnectedPacketConn) Close() error { //nolint:unused
+	return c.pConn.Close()
+}
+
+// LocalAddr is a stub
+func (c *disconnectedPacketConn) LocalAddr() net.Addr { //nolint:unused
+	if c.pConn != nil {
+		return c.pConn.LocalAddr()
+	}
+	return nil
+}
+
+// RemoteAddr is a stub
+func (c *disconnectedPacketConn) RemoteAddr() net.Addr { //nolint:unused
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.rAddr
+}
+
+// SetDeadline is a stub
+func (c *disconnectedPacketConn) SetDeadline(time.Time) error { //nolint:unused
+	return nil
+}
+
+// SetReadDeadline is a stub
+func (c *disconnectedPacketConn) SetReadDeadline(time.Time) error { //nolint:unused
+	return nil
+}
+
+// SetWriteDeadline is a stub
+func (c *disconnectedPacketConn) SetWriteDeadline(time.Time) error { //nolint:unused
+	return nil
+}

examples/ping-pong/pong.go → examples/ping-pong/pong/main.go

@@ -1,8 +1,6 @@
 // SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
 // SPDX-License-Identifier: MIT
 
-// +build pong
-
 package main
 
 import (
@@ -25,7 +23,11 @@ func main() {
 	if err != nil {
 		log.Panic(err)
 	}
-	defer conn.Close()
+	defer func() {
+		if closeErr := conn.Close(); closeErr != nil {
+			log.Panic(closeErr)
+		}
+	}()
 	fmt.Println("created a udp listener")
 
 	config := sctp.Config{
@@ -36,14 +38,22 @@ func main() {
 	if err != nil {
 		log.Panic(err)
 	}
-	defer a.Close()
-	fmt.Println("created a server")
+	defer func() {
+		if closeErr := a.Close(); closeErr != nil {
+			log.Panic(closeErr)
+		}
+	}()
+	defer fmt.Println("created a server")
 
 	stream, err := a.AcceptStream()
 	if err != nil {
 		log.Panic(err)
 	}
-	defer stream.Close()
+	defer func() {
+		if closeErr := stream.Close(); closeErr != nil {
+			log.Panic(closeErr)
+		}
+	}()
 	fmt.Println("accepted a stream")
 
 	// set unordered = true and 10ms treshold for dropping packets
@@ -58,7 +68,11 @@ func main() {
 		pingMsg := string(buff)
 		fmt.Println("received:", pingMsg)
 
-		fmt.Sscanf(pingMsg, "ping %d", &pongSeqNum)
+		_, err = fmt.Sscanf(pingMsg, "ping %d", &pongSeqNum)
+		if err != nil {
+			log.Panic(err)
+		}
+
 		pongMsg := fmt.Sprintf("pong %d", pongSeqNum)
 		_, err = stream.Write([]byte(pongMsg))
 		if err != nil {