Implement packed based receive API for UDP packets.

examples/UDP_Client/UDP_Client.ino

@@ -29,8 +29,6 @@ static T1SMacSettings const t1s_default_mac_settings;
 static IPAddress const UDP_SERVER_IP_ADDR = {192, 168,  42, 100 + 0};
 static uint16_t const UDP_CLIENT_PORT = 8889;
 static uint16_t const UDP_SERVER_PORT = 8888;
-static uint8_t udp_tx_msg_buf[256] = {0};
-static uint8_t udp_rx_msg_buf[256] = {0};
 
 /**************************************************************************************
  * GLOBAL VARIABLES
@@ -123,6 +121,7 @@ void loop()
     prev_udp_packet_sent = now;
 
     /* Prepare UDP packet. */
+    uint8_t udp_tx_msg_buf[256] = {0};
     int const tx_packet_size = snprintf((char *)udp_tx_msg_buf, sizeof(udp_tx_msg_buf), "Single-Pair Ethernet / 10BASE-T1S: packet cnt = %d", tx_packet_cnt);
 
     /* Send a UDP packet to the UDP server. */
@@ -143,7 +142,7 @@ void loop()
   int const rx_packet_size = udp_client.parsePacket();
   if (rx_packet_size)
   {
-    /* Receive incoming UDP packets. */
+    /* Print some metadata from received UDP packet. */
     Serial.print("Received ");
     Serial.print(rx_packet_size);
     Serial.print(" bytes from ");
@@ -152,15 +151,27 @@ void loop()
     Serial.print(udp_client.remotePort());
     Serial.println();
 
-    int const bytes_read = udp_client.read(udp_rx_msg_buf, sizeof(udp_rx_msg_buf));
-    if (bytes_read > 0) {
-      udp_rx_msg_buf[bytes_read] = 0;
-    }
     Serial.print("[");
     Serial.print(millis());
     Serial.print("] UDP_Client received packet content: \"");
-    Serial.print(reinterpret_cast<char *>(udp_rx_msg_buf));
+
+    /* Read from received UDP packet. */
+    size_t const UDP_RX_MSG_BUF_SIZE = 16 + 1; /* Reserve the last byte for the '\0' termination. */
+    uint8_t udp_rx_msg_buf[UDP_RX_MSG_BUF_SIZE] = {0};
+    int bytes_read = udp_client.read(udp_rx_msg_buf, UDP_RX_MSG_BUF_SIZE - 1);
+    while(bytes_read != 0)
+    {
+      /* Print received data to Serial. */
+      udp_rx_msg_buf[bytes_read] = '\0'; /* Terminate buffer so that we can print it as a C-string. */
+      Serial.print(reinterpret_cast<char *>(udp_rx_msg_buf));
+
+      /* Continue reading. */
+      bytes_read = udp_client.read(udp_rx_msg_buf, UDP_RX_MSG_BUF_SIZE - 1);
+    }
     Serial.println("\"");
+
+    /* Finish reading the current packet. */
+    udp_client.flush();
   }
 }
 

examples/UDP_Server/UDP_Server.ino

@@ -33,7 +33,6 @@ static T1SPlcaSettings const t1s_plca_settings{T1S_PLCA_NODE_ID};
 static T1SMacSettings const t1s_default_mac_settings;
 
 static uint16_t const UDP_SERVER_LOCAL_PORT = 8888;
-static uint8_t udp_rx_msg_buf[256] = {0};
 
 /**************************************************************************************
  * GLOBAL VARIABLES
@@ -119,29 +118,50 @@ void loop()
   }
 
   /* Check for incoming UDP packets. */
-  int const packet_size = udp_server.parsePacket();
-  if (packet_size)
+  int const rx_packet_size = udp_server.parsePacket();
+  if (rx_packet_size)
   {
-    /* Receive incoming UDP packets. */
+    std::vector<uint8_t> udp_tx_buf;
+    IPAddress const destination_ip = udp_server.remoteIP();
+    uint16_t const destination_port = udp_server.remotePort();
+
+    /* Print some metadata from received UDP packet. */
     Serial.print("Received ");
-    Serial.print(packet_size);
+    Serial.print(rx_packet_size);
     Serial.print(" bytes from ");
     Serial.print(udp_server.remoteIP());
     Serial.print(" port ");
     Serial.print(udp_server.remotePort());
     Serial.println();
 
-    int const bytes_read = udp_server.read(udp_rx_msg_buf, sizeof(udp_rx_msg_buf));
-    if (bytes_read > 0) {
-      udp_rx_msg_buf[bytes_read] = 0;
+    Serial.print("[");
+    Serial.print(millis());
+    Serial.print("] UDP_Client received packet content: \"");
+
+    /* Read from received UDP packet. */
+    size_t const UDP_RX_MSG_BUF_SIZE = 16 + 1; /* Reserve the last byte for the '\0' termination. */
+    uint8_t udp_rx_msg_buf[UDP_RX_MSG_BUF_SIZE] = {0};
+    int bytes_read = udp_server.read(udp_rx_msg_buf, UDP_RX_MSG_BUF_SIZE - 1);
+    while(bytes_read != 0)
+    {
+      /* Copy received data into transmit buffer for echo functionality. */
+      std::copy(udp_rx_msg_buf, udp_rx_msg_buf + bytes_read, std::back_inserter(udp_tx_buf));
+
+      /* Print received data to Serial. */
+      udp_rx_msg_buf[bytes_read] = '\0'; /* Terminate buffer so that we can print it as a C-string. */
+      Serial.print(reinterpret_cast<char *>(udp_rx_msg_buf));
+
+      /* Continue reading. */
+      bytes_read = udp_server.read(udp_rx_msg_buf, UDP_RX_MSG_BUF_SIZE - 1);
     }
-    Serial.print("UDP_Server received packet content: \"");
-    Serial.print(reinterpret_cast<char *>(udp_rx_msg_buf));
     Serial.println("\"");
 
+    /* Finish reading the current packet. */
+    udp_server.flush();
+
     /* Send back a reply, to the IP address and port we got the packet from. */
-    udp_server.beginPacket(udp_server.remoteIP(), udp_server.remotePort());
-    udp_server.write((const uint8_t *)udp_rx_msg_buf, packet_size);
+    udp_server.beginPacket(destination_ip, destination_port);
+    udp_server.write(udp_tx_buf.data(), udp_tx_buf.size());
     udp_server.endPacket();
   }
 }

src/Arduino_10BASE_T1S_UDP.cpp

@@ -26,8 +26,6 @@ static void lwIp_udp_raw_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, co
 
 Arduino_10BASE_T1S_UDP::Arduino_10BASE_T1S_UDP()
 : _udp_pcb{nullptr}
-, _remote_ip{0,0,0,0}
-, _remote_port{0}
 , _send_to_ip{0,0,0,0}
 , _send_to_port{0}
 {
@@ -131,77 +129,99 @@ size_t Arduino_10BASE_T1S_UDP::write(uint8_t data)
 
 size_t Arduino_10BASE_T1S_UDP::write(const uint8_t * buffer, size_t size)
 {
-  _tx_data.reserve(_tx_data.size() + size);
   std::copy(buffer, buffer + size, std::back_inserter(_tx_data));
   return size;
 }
 
 int Arduino_10BASE_T1S_UDP::parsePacket()
 {
-  return available();
+  if (_rx_pkt_list.size())
+    return _rx_pkt_list.front()->totalSize();
+  else
+    return 0;
 }
 
 int Arduino_10BASE_T1S_UDP::available()
 {
-  return _rx_data.size();
+  if (_rx_pkt_list.size())
+    return _rx_pkt_list.front()->available();
+  else
+    return 0;
 }
 
 int Arduino_10BASE_T1S_UDP::read()
 {
-  uint8_t const data = _rx_data.front();
-  _rx_data.pop_front();
-  return data;
+  if (_rx_pkt_list.size())
+   return _rx_pkt_list.front()->read();
+  else
+    return -1;
 }
 
 int Arduino_10BASE_T1S_UDP::read(unsigned char* buffer, size_t len)
 {
-  size_t bytes_read = 0;
-  for (; bytes_read < len && !_rx_data.empty(); bytes_read++)
-  {
-    buffer[bytes_read] = _rx_data.front();
-    _rx_data.pop_front();
-  }
-  return bytes_read;
+  if (_rx_pkt_list.size())
+    return _rx_pkt_list.front()->read(buffer, len);
+  else
+    return -1;
 }
 
 int Arduino_10BASE_T1S_UDP::read(char* buffer, size_t len)
 {
-  return read((unsigned char*)buffer, len);
+  if (_rx_pkt_list.size())
+    return _rx_pkt_list.front()->read(buffer, len);
+  else
+    return -1;
 }
 
 int Arduino_10BASE_T1S_UDP::peek()
 {
-  return _rx_data.front();
+  if (_rx_pkt_list.size())
+    return _rx_pkt_list.front()->peek();
+  else
+    return -1;
 }
 
 void Arduino_10BASE_T1S_UDP::flush()
 {
-  /* Nothing to be done. */
+  /* Drop packet from receive buffer. */
+  if (_rx_pkt_list.size())
+    _rx_pkt_list.pop_front();
 }
 
 IPAddress Arduino_10BASE_T1S_UDP::remoteIP()
 {
-  return _remote_ip;
+  if (_rx_pkt_list.size())
+    return _rx_pkt_list.front()->remoteIP();
+  else
+    return IPAddress();
 }
 
 uint16_t Arduino_10BASE_T1S_UDP::remotePort()
 {
-  return _remote_port;
+  if (_rx_pkt_list.size())
+    return _rx_pkt_list.front()->remotePort();
+  else
+    return 0;
 }
 
 void Arduino_10BASE_T1S_UDP::onUdpRawRecv(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, uint16_t port)
 {
   /* Obtain remote port and remote IP. */
-  _remote_ip = IPAddress(ip4_addr1(addr),
-                         ip4_addr2(addr),
-                         ip4_addr3(addr),
-                         ip4_addr4(addr));
-  _remote_port = port;
-
-  /* Copy data into buffer. */
-  std::copy((uint8_t *)p->payload,
-            (uint8_t *)p->payload + p->len,
-            std::back_inserter(_rx_data));
+  auto const remote_ip = IPAddress(
+    ip4_addr1(addr),
+    ip4_addr2(addr),
+    ip4_addr3(addr),
+    ip4_addr4(addr));
+  auto const remote_port = port;
+
+  /* Create UDP object. */
+  auto const rx_pkt = std::make_shared<UdpRxPacket>(
+    remote_ip,
+    remote_port,
+    (uint8_t const *)p->payload,
+    p->len);
+
+  _rx_pkt_list.push_back(rx_pkt);
 
   /* Free pbuf */
   pbuf_free(p);

src/Arduino_10BASE_T1S_UDP.h

@@ -14,8 +14,10 @@
  * INCLUDE
  **************************************************************************************/
 
+#include <list>
 #include <deque>
 #include <vector>
+#include <memory>
 
 #include <api/Udp.h>
 #include <api/IPAddress.h>
@@ -67,13 +69,74 @@ class Arduino_10BASE_T1S_UDP : public UDP
 
 
 private:
+  /* LWIP */
   struct udp_pcb * _udp_pcb;
 
-  IPAddress _remote_ip;
-  uint16_t _remote_port;
-  std::deque<uint8_t> _rx_data;
-
+  /* UDP TRANSMISSION */
   IPAddress _send_to_ip;
   uint16_t _send_to_port;
   std::vector<uint8_t> _tx_data;
+
+  /* UDP RECEPTION */
+  class UdpRxPacket
+  {
+  private:
+    IPAddress const _remote_ip;
+    uint16_t const _remote_port;
+    size_t const _rx_data_len;
+    std::deque<uint8_t> _rx_data;
+
+  public:
+    UdpRxPacket(
+      IPAddress const remote_ip,
+      uint16_t const remote_port,
+      uint8_t const * p_data,
+      size_t const data_len)
+      : _remote_ip(remote_ip)
+      , _remote_port(remote_port)
+      , _rx_data_len(data_len)
+      , _rx_data(p_data, p_data + data_len)
+    {
+    }
+
+    typedef std::shared_ptr<UdpRxPacket> SharedPtr;
+
+    IPAddress remoteIP() const { return _remote_ip; }
+    uint16_t remotePort() const { return _remote_port; }
+    size_t totalSize() const { return _rx_data_len; }
+
+    int available()
+    {
+      return _rx_data.size();
+    }
+
+    int read()
+    {
+      uint8_t const data = _rx_data.front();
+      _rx_data.pop_front();
+      return data;
+    }
+
+    int read(unsigned char* buffer, size_t len)
+    {
+      size_t bytes_read = 0;
+      for (; bytes_read < len && !_rx_data.empty(); bytes_read++)
+      {
+        buffer[bytes_read] = _rx_data.front();
+        _rx_data.pop_front();
+      }
+      return bytes_read;
+    }
+
+    int read(char* buffer, size_t len)
+    {
+      return read((unsigned char*)buffer, len);
+    }
+
+    int peek()
+    {
+      return _rx_data.front();
+    }
+  };
+  std::list<UdpRxPacket::SharedPtr> _rx_pkt_list;
 };