UIPUdp.cpp

/*
 UIPUdp.cpp - Arduino implementation of a uIP wrapper class.
 Copyright (c) 2013 Norbert Truchsess <norbert.truchsess@t-online.de>
 All rights reserved.

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "UIPEthernet.h"
#include "UIPUdp.h"
#include "Dns.h"

#ifdef UIPETHERNET_DEBUG_UDP
#include "HardwareSerial.h"
#endif

extern "C" {
#include "utility/uip-conf.h"
#include "utility/uip.h"
#include "utility/uip_arp.h"
}

#if UIP_UDP
#define UIP_ARPHDRSIZE 42
#define UDPBUF ((struct uip_udpip_hdr *)&uip_buf[UIP_LLH_LEN])

// Constructor
UIPUDP::UIPUDP()
{
  _uip_udp_conn = NULL;
  memset(&appdata,0,sizeof(appdata));
  UIPEthernet.set_uip_udp_callback(&UIPUDP::uip_callback);
}

// initialize, start listening on specified port. Returns 1 if successful, 0 if there are no sockets available to use
uint8_t
UIPUDP::begin(uint16_t port)
{
  if (!_uip_udp_conn)
    {
      _uip_udp_conn = uip_udp_new(NULL, 0);
    }
  if (_uip_udp_conn)
    {
      uip_udp_bind(_uip_udp_conn,htons(port));
      _uip_udp_conn->appstate.user = &appdata;
      return 1;
    }
  return 0;
}

// Finish with the UDP socket
void
UIPUDP::stop()
{
  if (_uip_udp_conn)
    {
      flush();
      uip_udp_remove(_uip_udp_conn);
      _uip_udp_conn->appstate.user = NULL;
      _uip_udp_conn=NULL;
      if (appdata.packet_in != NOBLOCK)
        {
          UIPEthernet.network.freeBlock(appdata.packet_in);
          appdata.packet_in = NOBLOCK;
        }
      uint8_t i = 0;
      memhandle* packet = &appdata.packets_in[0];
      while (*packet != NOBLOCK && i < UIP_UDP_NUMPACKETS)
        {
          UIPEthernet.network.freeBlock(*packet);
          *packet++ = NOBLOCK;
          i++;
        }
      if (appdata.packet_out != NOBLOCK)
        {
          UIPEthernet.network.freeBlock(appdata.packet_out);
          appdata.packet_out = NOBLOCK;
        }
    }
}

// Sending UDP packets

// Start building up a packet to send to the remote host specific in ip and port
// Returns 1 if successful, 0 if there was a problem with the supplied IP address or port
int
UIPUDP::beginPacket(IPAddress ip, uint16_t port)
{
  UIPEthernet.tick();
  if (ip && port)
    {
      uip_ipaddr_t ripaddr;
      uip_ip_addr(&ripaddr, ip);
#ifdef UIPETHERNET_DEBUG_UDP
      Serial.print("udp beginPacket, ");
#endif
      if (_uip_udp_conn)
        {
          _uip_udp_conn->rport = htons(port);
          uip_ipaddr_copy(_uip_udp_conn->ripaddr, &ripaddr);
        }
      else
        {
          _uip_udp_conn = uip_udp_new(&ripaddr,htons(port));
          if (_uip_udp_conn)
            {
#ifdef UIPETHERNET_DEBUG_UDP
              Serial.print("new connection, ");
#endif
              _uip_udp_conn->appstate.user = &appdata;
            }
          else
            {
#ifdef UIPETHERNET_DEBUG_UDP
              Serial.println("failed to allocate new connection");
#endif
              return 0;
            }
        }
#ifdef UIPETHERNET_DEBUG_UDP
          Serial.print("rip: ");
          Serial.print(ip);
          Serial.print(", port: ");
          Serial.println(port);
#endif
    }
  if (_uip_udp_conn)
    {
      if (appdata.packet_out == NOBLOCK)
        {
          appdata.packet_out = UIPEthernet.network.allocBlock(UIP_UDP_MAXPACKETSIZE);
          appdata.out_pos = UIP_UDP_PHYH_LEN;
          if (appdata.packet_out != NOBLOCK)
            return 1;
#ifdef UIPETHERNET_DEBUG_UDP
          else
            Serial.println("failed to allocate memory for packet");
#endif
        }
#ifdef UIPETHERNET_DEBUG_UDP
      else
        Serial.println("previous packet on that connection not sent yet");
#endif
    }
  return 0;
}

// Start building up a packet to send to the remote host specific in host and port
// Returns 1 if successful, 0 if there was a problem resolving the hostname or port
int
UIPUDP::beginPacket(const char *host, uint16_t port)
{
  // Look up the host first
  int ret = 0;
  DNSClient dns;
  IPAddress remote_addr;

  dns.begin(UIPEthernet.dnsServerIP());
  ret = dns.getHostByName(host, remote_addr);
  if (ret == 1) {
    return beginPacket(remote_addr, port);
  } else {
    return ret;
  }
}

// Finish off this packet and send it
// Returns 1 if the packet was sent successfully, 0 if there was an error
int
UIPUDP::endPacket()
{
  if (_uip_udp_conn && appdata.packet_out != NOBLOCK)
    {
      appdata.send = true;
      UIPEthernet.network.resizeBlock(appdata.packet_out,0,appdata.out_pos);
      uip_udp_periodic_conn(_uip_udp_conn);
      if (uip_len > 0)
        {
          UIPEthernet.network_send();
          return 1;
        }
    }
  return 0;
}

// Write a single byte into the packet
size_t
UIPUDP::write(uint8_t c)
{
  return write(&c,1);
}

// Write size bytes from buffer into the packet
size_t
UIPUDP::write(const uint8_t *buffer, size_t size)
{
  if (appdata.packet_out != NOBLOCK)
    {
      size_t ret = UIPEthernet.network.writePacket(appdata.packet_out,appdata.out_pos,(uint8_t*)buffer,size);
      appdata.out_pos += ret;
      return ret;
    }
  return 0;
}

// Start processing the next available incoming packet
// Returns the size of the packet in bytes, or 0 if no packets are available
int
UIPUDP::parsePacket()
{
  UIPEthernet.tick();
  if (appdata.packet_in != NOBLOCK)
    {
#ifdef UIPETHERNET_DEBUG_UDP
      Serial.print("udp parsePacket freeing previous packet: ");
      Serial.println(appdata.packet_in);
#endif;
      UIPEthernet.network.freeBlock(appdata.packet_in);
    }
  memhandle *packet = &appdata.packets_in[0];
  appdata.packet_in = *packet;
  if (appdata.packet_in != NOBLOCK)
    {
#ifdef UIPETHERNET_DEBUG_UDP
      Serial.print("udp parsePacket received packet: ");
      Serial.print(appdata.packet_in);
#endif
      if (UIP_UDP_NUMPACKETS > 1)
        {
          uint8_t i = 1;
          memhandle* p = packet+1;
freeloop:
          *packet = *p;
          if (*packet == NOBLOCK)
            goto freeready;
          packet++;
          if (i < UIP_UDP_NUMPACKETS-1)
            {
              i++;
              p++;
              goto freeloop;
            }
        }
      *packet = NOBLOCK;
freeready:
      int size = UIPEthernet.network.blockSize(appdata.packet_in);
#ifdef UIPETHERNET_DEBUG_UDP
      Serial.print(", size: ");
      Serial.println(size);
#endif
      return size;
    }
  return 0;
}

// Number of bytes remaining in the current packet
int
UIPUDP::available()
{
  UIPEthernet.tick();
  if (appdata.packet_in != NOBLOCK)
    {
      return UIPEthernet.network.blockSize(appdata.packet_in);
    }
  return 0;
}

// Read a single byte from the current packet
int
UIPUDP::read()
{
  unsigned char c;
  if (read(&c,1) > 0)
    {
      return c;
    }
  return -1;
}

// Read up to len bytes from the current packet and place them into buffer
// Returns the number of bytes read, or 0 if none are available
int
UIPUDP::read(unsigned char* buffer, size_t len)
{
  UIPEthernet.tick();
  if (appdata.packet_in != NOBLOCK)
    {
      int read = UIPEthernet.network.readPacket(appdata.packet_in,0,buffer,len);
      UIPEthernet.network.resizeBlock(appdata.packet_in,read);
      return read;
    }
  return 0;
}

// Return the next byte from the current packet without moving on to the next byte
int
UIPUDP::peek()
{
  UIPEthernet.tick();
  if (appdata.packet_in != NOBLOCK)
    {
      unsigned char c;
      if (UIPEthernet.network.readPacket(appdata.packet_in,0,&c,1) == 1)
        return c;
    }
  return -1;
}

// Finish reading the current packet
void
UIPUDP::flush()
{
  UIPEthernet.tick();
  if (appdata.packet_in != NOBLOCK)
    {
      UIPEthernet.network.freeBlock(appdata.packet_in);
      appdata.packet_in = NOBLOCK;
    }
}

// Return the IP address of the host who sent the current incoming packet
IPAddress
UIPUDP::remoteIP()
{
  return appdata.ripaddr;
}

// Return the port of the host who sent the current incoming packet
uint16_t
UIPUDP::remotePort()
{
  return appdata.rport;
}

void UIPUDP::uip_callback(uip_udp_appstate_t *s) {
  if (appdata_t *data = (appdata_t *)s->user)
    {
      if (uip_newdata())
        {
          data->rport = ntohs(UDPBUF->srcport);
          data->ripaddr = ip_addr_uip(UDPBUF->srcipaddr);
          memhandle *packet = &data->packets_in[0];
          uint8_t i = 0;
          do
            {
              if (*packet == NOBLOCK)
                {
                  *packet = UIPEthernet.network.allocBlock(ntohs(UDPBUF->udplen)-UIP_UDPH_LEN);
                  //if we are unable to allocate memory the packet is dropped. udp doesn't guarantee packet delivery
                  if (*packet != NOBLOCK)
                    {
                      //discard Linklevel and IP and udp-header and any trailing bytes:
                      UIPEthernet.network.copyPacket(*packet,0,UIPEthernet.in_packet,UIP_UDP_PHYH_LEN,UIPEthernet.network.blockSize(*packet));
    #ifdef UIPETHERNET_DEBUG_UDP
                      Serial.print("udp, uip_newdata received packet: ");
                      Serial.print(*packet);
                      Serial.print(", slot: ");
                      Serial.print(i);
                      Serial.print(", size: ");
                      Serial.println(UIPEthernet.network.blockSize(*packet));
    #endif
                      break;
                    }
                }
              packet++;
              i++;
            }
          while (i < UIP_UDP_NUMPACKETS);
        }
      if (uip_poll() && data->send)
        {
          //set uip_slen (uip private) by calling uip_udp_send
#ifdef UIPETHERNET_DEBUG_UDP
          Serial.print("udp, uip_poll preparing packet to send: ");
          Serial.print(data->packet_out);
          Serial.print(", size: ");
          Serial.println(UIPEthernet.network.blockSize(data->packet_out));
#endif
          UIPEthernet.uip_packet = data->packet_out;
          data->packet_out = NOBLOCK;
          UIPEthernet.uip_hdrlen = UIP_UDP_PHYH_LEN;
          UIPEthernet.packetstate |= UIPETHERNET_SENDPACKET;
          uip_udp_send(data->out_pos - (UIP_UDP_PHYH_LEN));
          uip_process(UIP_UDP_SEND_CONN); //generate udp + ip headers
          uip_arp_out(); //add arp
          if (uip_len == UIP_ARPHDRSIZE)
            {
              UIPEthernet.packetstate &= ~UIPETHERNET_SENDPACKET;
#ifdef UIPETHERNET_DEBUG_UDP
              Serial.println("udp, uip_poll results in ARP-packet");
#endif
            }
          else
          //arp found ethaddr for ip (otherwise packet is replaced by arp-request)
            {
              data->send = false;
#ifdef UIPETHERNET_DEBUG_UDP
              Serial.print("udp, uip_packet to send: ");
              Serial.println(UIPEthernet.uip_packet);
#endif
            }
        }
    }
}
#endif