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/*--------------------------------------------------------------------
 * TITLE: Plasma TCP/IP Protocol Stack
 * AUTHOR: Steve Rhoads (rhoadss@yahoo.com)
 * DATE CREATED: 4/22/06
 * FILENAME: tcpip.c
 * PROJECT: Plasma CPU core
 * COPYRIGHT: Software placed into the public domain by the author.
 *    Software 'as is' without warranty.  Author liable for nothing.
 * DESCRIPTION:
 *    Plasma TCP/IP Protocol Stack
 *
 *    Possible call stack when receiving a packet:
 *       IPMainThread()
 *          IPProcessEthernetPacket()
 *             IPProcessTCPPacket()
 *                TCPSendPacket()
 *                   IPSendPacket()
 *                      IPChecksum()
 *                      IPSendFrame()
 *                         FrameInsert()
 *--------------------------------------------------------------------*/
#ifdef WIN32
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#define _LIBC
#endif
#include "rtos.h"
#include "tcpip.h"
 
#ifdef WIN32
#undef OS_CriticalBegin
#undef OS_CriticalEnd
#define OS_CriticalBegin() 0
#define OS_CriticalEnd(A)
#define OS_ThreadCreate(A,B,C,D,E) 0
#define OS_ThreadSleep(A)
#define OS_ThreadTime() 0
#define OS_ThreadSelf() 0
#define OS_MutexCreate(A) NULL
#define OS_MutexPend(A)
#define OS_MutexPost(A)
#define OS_MQueueCreate(A,B,C) 0
#define OS_MQueueSend(A,B) 0
#define OS_MQueueGet(A,B,C) 0
#define UartPacketConfig(A,B,C)
#define UartPacketSend(A,B)
#define UartPrintf printf
#define UartPrintfCritical printf
#define Led(A)
#endif
 
//ETHER FIELD                 OFFSET   LENGTH   VALUE
#define ETHERNET_DEST         0        //6
#define ETHERNET_SOURCE       6        //6
#define ETHERNET_FRAME_TYPE   12       //2      IP=0x0800; ARP=0x0806
 
//ARP   FIELD                 OFFSET   LENGTH   VALUE
#define ARP_HARD_TYPE         14       //2      0x0001
#define ARP_PROT_TYPE         16       //2      0x0800
#define ARP_HARD_SIZE         18       //1      0x06
#define ARP_PROT_SIZE         19       //1      0x04
#define ARP_OP                20       //2      ARP=1;ARPreply=2
#define ARP_ETHERNET_SENDER   22       //6
#define ARP_IP_SENDER         28       //4
#define ARP_ETHERNET_TARGET   32       //6
#define ARP_IP_TARGET         38       //4
#define ARP_PAD               42       //18     0
 
//IP    FIELD                 OFFSET   LENGTH   VALUE
#define IP_VERSION_LENGTH     14       //1      0x45
#define IP_TYPE_OF_SERVICE    15       //1      0x00
#define IP_LENGTH             16       //2
#define IP_ID16               18       //2
#define IP_FRAG_OFFSET        20       //2
#define IP_TIME_TO_LIVE       22       //1      0x80
#define IP_PROTOCOL           23       //1      TCP=0x06;PING=0x01;UDP=0x11
#define IP_CHECKSUM           24       //2
#define IP_SOURCE             26       //4
#define IP_DEST               30       //4
 
//PSEUDO FIELD                OFFSET   LENGTH   VALUE
#define PSEUDO_IP_SOURCE      0        //4
#define PSEUDO_IP_DEST        4        //4
#define PSEUDO_ZERO           8        //1      0
#define PSEUDO_IP_PROTOCOL    9        //1
#define PSEUDO_LENGTH         10       //2
 
//UDP   FIELD                 OFFSET   LENGTH   VALUE
#define UDP_SOURCE_PORT       34       //2
#define UDP_DEST_PORT         36       //2
#define UDP_LENGTH            38       //2
#define UDP_CHECKSUM          40       //2
#define UDP_DATA              42
 
//DHCP  FIELD                 OFFSET   LENGTH   VALUE
#define DHCP_OPCODE           42       //1      REQUEST=1;REPLY=2
#define DHCP_HW_TYPE          43       //1      1
#define DHCP_HW_LEN           44       //1      6
#define DHCP_HOP_COUNT        45       //1      0
#define DHCP_TRANS_ID         46       //4
#define DHCP_NUM_SEC          50       //2      0
#define DHCP_UNUSED           52       //2
#define DHCP_CLIENT_IP        54       //4
#define DHCP_YOUR_IP          58       //4
#define DHCP_SERVER_IP        62       //4
#define DHCP_GATEWAY_IP       66       //4
#define DHCP_CLIENT_ETHERNET  70       //16
#define DHCP_SERVER_NAME      86       //64
#define DHCP_BOOT_FILENAME    150      //128
#define DHCP_MAGIC_COOKIE     278      //4      0x63825363
#define DHCP_OPTIONS          282      //N
 
#define DHCP_MESSAGE_TYPE     53       //1 type
#define DHCP_DISCOVER         1
#define DHCP_OFFER            2
#define DHCP_REQUEST          3
#define DHCP_ACK              5
#define DHCP_REQUEST_IP       50       //4 ip
#define DHCP_REQUEST_SERV_IP  54       //4 ip
#define DHCP_CLIENT_ID        61       //7 1 ethernet
#define DHCP_HOST_NAME        12       //6 plasma
#define DHCP_PARAMS           55       //4 1=subnet; 15=domain_name; 3=router; 6=dns
#define DHCP_PARAM_SUBNET     1
#define DHCP_PARAM_ROUTER     3
#define DHCP_PARAM_DNS        6
#define DHCP_END_OPTION       0xff
 
//DHCP  FIELD                 OFFSET   LENGTH   VALUE
#define DNS_ID                0        //2    
#define DNS_FLAGS             2        //2      
#define DNS_NUM_QUESTIONS     4        //2      1 
#define DNS_NUM_ANSWERS_RR    6        //2      0/1
#define DNS_NUM_AUTHORITY_RR  8        //2      0 
#define DNS_NUM_ADDITIONAL_RR 10       //2      0
#define DNS_QUESTIONS         12       //2   
 
#define DNS_FLAGS_RESPONSE    0x8000
#define DNS_FLAGS_RECURSIVE   0x0100
#define DNS_FLAGS_ERROR       0x0003
#define DNS_FLAGS_OK          0x0000
#define DNS_QUERY_TYPE_IP     1
#define DNS_QUERY_CLASS       1
#define DNS_PORT              53
 
//TCP   FIELD                 OFFSET   LENGTH   VALUE
#define TCP_SOURCE_PORT       34       //2
#define TCP_DEST_PORT         36       //2
#define TCP_SEQ               38       //4
#define TCP_ACK               42       //4
#define TCP_HEADER_LENGTH     46       //1      0x50
#define TCP_FLAGS             47       //1      SYNC=0x2;ACK=0x10;FIN=0x1
#define TCP_WINDOW_SIZE       48       //2
#define TCP_CHECKSUM          50       //2
#define TCP_URGENT_POINTER    52       //2
#define TCP_DATA              54       //length-N
 
#define TCP_FLAGS_FIN         1
#define TCP_FLAGS_SYN         2
#define TCP_FLAGS_RST         4
#define TCP_FLAGS_PSH         8
#define TCP_FLAGS_ACK         16
 
//PING  FIELD                 OFFSET   LENGTH   VALUE
#define PING_TYPE             34       //1      SEND=8;REPLY=0
#define PING_CODE             35       //1      0
#define PING_CHECKSUM         36       //2
#define PING_ID               38       //2
#define PING_SEQUENCE         40       //2
#define PING_DATA             44
 
static void IPClose2(IPSocket *Socket);
 
static uint8 ethernetAddressNull[] =    {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
static uint8 ethernetAddressGateway[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
#ifndef WIN32
static uint8 ethernetAddressPlasma[] =  {0x00, 0x10, 0xdd, 0xce, 0x15, 0xd4};
#else
static uint8 ethernetAddressPlasma[] =  {0x00, 0x10, 0xdd, 0xce, 0x15, 0xd5};
#endif
 
static uint8 ipAddressPlasma[] =  {0x9d, 0xfe, 0x28, 10};   //changed by DHCP
static uint8 ipAddressGateway[] = {0xff, 0xff, 0xff, 0xff}; //changed by DHCP
static uint32 ipAddressDns;                                 //changed by DHCP
 
static OS_Mutex_t *IPMutex;
static int FrameFreeCount=FRAME_COUNT;
static IPFrame *FrameFreeHead;
static IPFrame *FrameSendHead;
static IPFrame *FrameSendTail;
static IPFrame *FrameResendHead;
static IPFrame *FrameResendTail;
static IPSocket *SocketHead;
static uint32 Seconds;
static int DhcpRetrySeconds;
static IPFuncPtr FrameSendFunc;
static OS_MQueue_t *IPMQueue;
static OS_Thread_t *IPThread;
int IPVerbose=1;
 
static const unsigned char dhcpDiscover[] = {
   0xff, 0xff, 0xff, 0xff, 0xff, 0xff,             //dest
   0x00, 0x10, 0xdd, 0xce, 0x15, 0xd4,             //src
   0x08, 0x00,
   0x45, 0x00, 0x01, 0x48, 0x2e, 0xf5, 0x00, 0x00, //ip
   0x80, 0x11, 0x0a, 0xb1, 0x00, 0x00, 0x00, 0x00,
   0xff, 0xff, 0xff, 0xff,
   0x00, 0x44, 0x00, 0x43, 0x01, 0x34, 0x45, 0x66, //udp
   0x01, 0x01, 0x06, 0x00, 0x69, 0x26, 0xb5, 0x52  //dhcp
};
 
static const unsigned char dhcpOptions[] = {
   0x63, 0x82, 0x53, 0x63,      //cookie
   0x35, 0x01, 0x01,            //DHCP Discover
   0x3d, 0x07, 0x01, 0x00, 0x10, 0xdd, 0xce, 0x15, 0xd4, //Client identifier
#ifndef WIN32
   0x0c, 0x06, 'p', 'l', 'a', 's', 'm', 'a',             //Host name
#else
   0x0c, 0x06, 'p', 'l', 'a', 's', 'm', 'b',             //Host name
#endif
   0x37, 0x03, DHCP_PARAM_SUBNET, DHCP_PARAM_ROUTER, DHCP_PARAM_DNS, //Parameters
   DHCP_END_OPTION
};
 
 
//Get a free frame; can be called from an ISR
IPFrame *IPFrameGet(int freeCount)
{
   IPFrame *frame=NULL;
   uint32 state;
 
   state = OS_CriticalBegin();
   if(FrameFreeCount > freeCount)
   {
      --FrameFreeCount;
      frame = FrameFreeHead;
      if(FrameFreeHead)
         FrameFreeHead = FrameFreeHead->next;
   }
   OS_CriticalEnd(state);
   if(frame)
   {
      assert(frame->state == 0);
      frame->state = 1;
   }
   return frame;
}
 
 
static void FrameFree(IPFrame *frame)
{
   uint32 state;
 
   assert(frame->state == 1);
   frame->state = 0;
   state = OS_CriticalBegin();
   frame->next = FrameFreeHead;
   FrameFreeHead = frame;
   ++FrameFreeCount;
   OS_CriticalEnd(state);
}
 
 
static void FrameInsert(IPFrame **head, IPFrame **tail, IPFrame *frame)
{
   assert(frame->state == 1);
   frame->state = 2;
   OS_MutexPend(IPMutex);
   frame->prev = NULL;
   frame->next = *head;
   if(*head)
      (*head)->prev = frame;
   *head = frame;
   if(*tail == NULL)
      *tail = frame;
   OS_MutexPost(IPMutex);
}
 
 
static void FrameRemove(IPFrame **head, IPFrame **tail, IPFrame *frame)
{
   assert(frame->state == 2);
   frame->state = 1;
   if(frame->prev)
      frame->prev->next = frame->next;
   else
      *head = frame->next;
   if(frame->next)
      frame->next->prev = frame->prev;
   else
      *tail = frame->prev;
   frame->prev = NULL;
   frame->next = NULL;
}
 
 
static int IPChecksum(int checksum, const unsigned char *data, int length)
{
   int i;
   checksum = ~checksum & 0xffff;
   for(i = 0; i < length-1; i += 2)
   {
      checksum += (data[i] << 8) | data[i+1];
   }
   if(i < length)
      checksum += data[i] << 8;
   while(checksum >> 16)
      checksum = (checksum & 0xffff) + (checksum >> 16);
   checksum = ~checksum & 0xffff;
   return checksum;
}
 
 
static int EthernetVerifyChecksums(const unsigned char *packet, int length)
{
   int checksum, length2;
   unsigned char pseudo[12];
 
   //Calculate checksums
   if(packet[ETHERNET_FRAME_TYPE+1] == 0x00)  //IP
   {
      checksum = IPChecksum(0xffff, packet+IP_VERSION_LENGTH, 20);
      if(checksum)
         return -1;
      if(packet[IP_PROTOCOL] == 0x01)         //PING
      {
         checksum = IPChecksum(0xffff, packet+PING_TYPE, length-PING_TYPE);
      }
      else if(packet[IP_PROTOCOL] == 0x11)    //UDP
      {
         if(packet[UDP_CHECKSUM] == 0 && packet[UDP_CHECKSUM+1] == 0)
            return 0;
         memcpy(pseudo+PSEUDO_IP_SOURCE, packet+IP_SOURCE, 4);
         memcpy(pseudo+PSEUDO_IP_DEST, packet+IP_DEST, 4);
         pseudo[PSEUDO_ZERO] = 0;
         pseudo[PSEUDO_IP_PROTOCOL] = packet[IP_PROTOCOL];
         memcpy(pseudo+PSEUDO_LENGTH, packet+UDP_LENGTH, 2);
         checksum = IPChecksum(0xffff, pseudo, 12);
         length2 = (packet[UDP_LENGTH] << 8) + packet[UDP_LENGTH+1];
         checksum = IPChecksum(checksum, packet+UDP_SOURCE_PORT, length);
      }
      else if(packet[IP_PROTOCOL] == 0x06)    //TCP
      {
         memcpy(pseudo+PSEUDO_IP_SOURCE, packet+IP_SOURCE, 4);
         memcpy(pseudo+PSEUDO_IP_DEST, packet+IP_DEST, 4);
         pseudo[PSEUDO_ZERO] = 0;
         pseudo[PSEUDO_IP_PROTOCOL] = packet[IP_PROTOCOL];
         length = (packet[IP_LENGTH] << 8) + packet[IP_LENGTH+1];
         length2 = length - 20;
         pseudo[PSEUDO_LENGTH] = (unsigned char)(length2 >> 8);
         pseudo[PSEUDO_LENGTH+1] = (unsigned char)length2;
         checksum = IPChecksum(0xffff, pseudo, 12);
         checksum = IPChecksum(checksum, packet+TCP_SOURCE_PORT, length2);
      }
      if(checksum)
         return -1;
   }
   return 0;
}
 
 
static void IPFrameReschedule(IPFrame *frame)
{
   int length;
   length = frame->length - TCP_DATA;
   if(frame->packet[TCP_FLAGS] & (TCP_FLAGS_FIN | TCP_FLAGS_SYN))
      ++length;
   if(frame->socket == NULL || frame->socket->state == IP_UDP || length == 0 ||
      frame->socket->state == IP_PING || ++frame->retryCnt > 4)
   {
      FrameFree(frame);     //can't be ACK'ed
   }
   else
   {
      //Put on resend list until TCP ACK'ed
      frame->timeout = RETRANSMIT_TIME;
      FrameInsert(&FrameResendHead, &FrameResendTail, frame);
   }
}
 
 
static void IPSendFrame(IPFrame *frame)
{
   uint32 message[4];
 
   if(FrameSendFunc)
   {
      //Single threaded
      FrameSendFunc(frame->packet, frame->length);
      IPFrameReschedule(frame);
   }
   else
   {
      //Add Packet to send queue
      FrameInsert(&FrameSendHead, &FrameSendTail, frame);
 
      //Wakeup sender thread
      message[0] = 2;
      OS_MQueueSend(IPMQueue, message);
   }
}
 
 
static void IPSendPacket(IPSocket *socket, IPFrame *frame, int length)
{
   int checksum, length2=length;
   unsigned char pseudo[12], *packet=frame->packet;
 
   frame->length = (uint16)length;
 
   //Calculate checksums
   if(packet[ETHERNET_FRAME_TYPE+1] == 0x00)  //IP
   {
      length2 = length - IP_VERSION_LENGTH;
      packet[IP_LENGTH] = (uint8)(length2 >> 8);
      packet[IP_LENGTH+1] = (uint8)length2;
      memset(packet+IP_CHECKSUM, 0, 2);
      checksum = IPChecksum(0xffff, packet+IP_VERSION_LENGTH, 20);
      packet[IP_CHECKSUM] = (unsigned char)(checksum >> 8);
      packet[IP_CHECKSUM+1] = (unsigned char)checksum;
      if(packet[IP_PROTOCOL] == 0x01)         //PING
      {
         memset(packet+PING_CHECKSUM, 0, 2);
         checksum = IPChecksum(0xffff, packet+PING_TYPE, length-PING_TYPE);
         packet[PING_CHECKSUM] = (unsigned char)(checksum >> 8);
         packet[PING_CHECKSUM+1] = (unsigned char)checksum;
      }
      else if(packet[IP_PROTOCOL] == 0x11)    //UDP
      {
         length2 = length - UDP_SOURCE_PORT;
         packet[UDP_LENGTH] = (uint8)(length2 >> 8);
         packet[UDP_LENGTH+1] = (uint8)length2;
         memcpy(pseudo+PSEUDO_IP_SOURCE, packet+IP_SOURCE, 4);
         memcpy(pseudo+PSEUDO_IP_DEST, packet+IP_DEST, 4);
         pseudo[PSEUDO_ZERO] = 0;
         pseudo[PSEUDO_IP_PROTOCOL] = packet[IP_PROTOCOL];
         memcpy(pseudo+PSEUDO_LENGTH, packet+UDP_LENGTH, 2);
         checksum = IPChecksum(0xffff, pseudo, 12);
         memset(packet+UDP_CHECKSUM, 0, 2);
         length2 = (packet[UDP_LENGTH] << 8) + packet[UDP_LENGTH+1];
         checksum = IPChecksum(checksum, packet+UDP_SOURCE_PORT, length2);
         packet[UDP_CHECKSUM] = (unsigned char)(checksum >> 8);
         packet[UDP_CHECKSUM+1] = (unsigned char)checksum;
      }
      else if(packet[IP_PROTOCOL] == 0x06)    //TCP
      {
         memcpy(pseudo+PSEUDO_IP_SOURCE, packet+IP_SOURCE, 4);
         memcpy(pseudo+PSEUDO_IP_DEST, packet+IP_DEST, 4);
         pseudo[PSEUDO_ZERO] = 0;
         pseudo[PSEUDO_IP_PROTOCOL] = packet[IP_PROTOCOL];
         length2 = (packet[IP_LENGTH] << 8) + packet[IP_LENGTH+1];
         length2 = length2 - 20;
         pseudo[PSEUDO_LENGTH] = (unsigned char)(length2 >> 8);
         pseudo[PSEUDO_LENGTH+1] = (unsigned char)length2;
         checksum = IPChecksum(0xffff, pseudo, 12);
         memset(packet+TCP_CHECKSUM, 0, 2);
         checksum = IPChecksum(checksum, packet+TCP_SOURCE_PORT, length2);
         packet[TCP_CHECKSUM] = (unsigned char)(checksum >> 8);
         packet[TCP_CHECKSUM+1] = (unsigned char)checksum;
      }
   }
 
   length2 = length - TCP_DATA;
   if(socket && (packet[TCP_FLAGS] & (TCP_FLAGS_FIN | TCP_FLAGS_SYN)))
      length2 = 1;
   frame->socket = socket;
   frame->timeout = 0;
   frame->retryCnt = 0;
   if(socket)
      frame->seqEnd = socket->seq + length2;
   IPSendFrame(frame);
}
 
 
static void TCPSendPacket(IPSocket *socket, IPFrame *frame, int length)
{
   uint8 *packet = frame->packet;
   int flags, count;
 
   flags = packet[TCP_FLAGS];
   memcpy(packet, socket->headerSend, TCP_SEQ);
   packet[TCP_FLAGS] = (uint8)flags | (socket->headerSend[TCP_FLAGS] & TCP_FLAGS_PSH);
   if(flags & TCP_FLAGS_SYN)
      packet[TCP_HEADER_LENGTH] = 0x60;  //set maximum segment size
   else
      packet[TCP_HEADER_LENGTH] = 0x50;
   packet[TCP_SEQ]   = (uint8)(socket->seq >> 24);
   packet[TCP_SEQ+1] = (uint8)(socket->seq >> 16);
   packet[TCP_SEQ+2] = (uint8)(socket->seq >> 8);
   packet[TCP_SEQ+3] = (uint8)socket->seq;
   packet[TCP_ACK]   = (uint8)(socket->ack >> 24);
   packet[TCP_ACK+1] = (uint8)(socket->ack >> 16);
   packet[TCP_ACK+2] = (uint8)(socket->ack >> 8);
   packet[TCP_ACK+3] = (uint8)socket->ack;
   count = FrameFreeCount - FRAME_COUNT_WINDOW;
   if(count < 1)
      count = 1;
   if(count > 4)
      count = 4;
   count *= 512;
   packet[TCP_WINDOW_SIZE] = (uint8)(count >> 8);
   packet[TCP_WINDOW_SIZE+1] = (uint8)count;
   packet[TCP_URGENT_POINTER] = 0;
   packet[TCP_URGENT_POINTER+1] = 0;
   IPSendPacket(socket, frame, length);
}
 
 
static void EthernetCreateResponse(unsigned char *packetOut,
                                   const unsigned char *packet,
                                   int length)
{
   //Swap destination and source fields
   memcpy(packetOut, packet, length);
   memcpy(packetOut+ETHERNET_DEST, packet+ETHERNET_SOURCE, 6);
   memcpy(packetOut+ETHERNET_SOURCE, packet+ETHERNET_DEST, 6);
   if(packet[ETHERNET_FRAME_TYPE+1] == 0x00)  //IP
   {
      memcpy(packetOut+IP_SOURCE, packet+IP_DEST, 4);
      memcpy(packetOut+IP_DEST, packet+IP_SOURCE, 4);
      if(packet[IP_PROTOCOL] == 0x06 || packet[IP_PROTOCOL] == 0x11)   //TCP/UDP
      {
         memcpy(packetOut+TCP_SOURCE_PORT, packet+TCP_DEST_PORT, 2);
         memcpy(packetOut+TCP_DEST_PORT, packet+TCP_SOURCE_PORT, 2);
      }
   }
}
 
 
static void IPDhcp(const unsigned char *packet, int length, int state)
{
   uint8 *packetOut, *ptr;
   const uint8 *ptr2;
   IPFrame *frame;
   static int request=0;
 
   if(state == 1)
   {
      //Create DHCP Discover
      frame = IPFrameGet(0);
      if(frame == NULL)
         return;
      packetOut = frame->packet;
      memset(packetOut, 0, 512);
      memcpy(packetOut, dhcpDiscover, sizeof(dhcpDiscover));
      memcpy(packetOut+ETHERNET_SOURCE, ethernetAddressPlasma, 6);
      memcpy(packetOut+DHCP_CLIENT_ETHERNET, ethernetAddressPlasma, 6);
      memcpy(packetOut+DHCP_MAGIC_COOKIE, dhcpOptions, sizeof(dhcpOptions));
      memcpy(packetOut+DHCP_MAGIC_COOKIE+10, ethernetAddressPlasma, 6);
      IPSendPacket(NULL, frame, 400);
      request = DHCP_DISCOVER;
      DhcpRetrySeconds = RETRANSMIT_TIME;
   }
   else if(state == 2 && memcmp(packet+DHCP_CLIENT_ETHERNET, ethernetAddressPlasma, 6) == 0)
   {
      if(packet[DHCP_MAGIC_COOKIE+6] == DHCP_OFFER && request == DHCP_DISCOVER)
      {
         //Process DHCP Offer and send DHCP Request
         frame = IPFrameGet(0);
         if(frame == NULL)
            return;
         packetOut = frame->packet;
         memset(packetOut, 0, 512);
         memcpy(packetOut, dhcpDiscover, sizeof(dhcpDiscover));
         memcpy(packetOut+ETHERNET_SOURCE, ethernetAddressPlasma, 6);
         memcpy(packetOut+DHCP_CLIENT_ETHERNET, ethernetAddressPlasma, 6);
         memcpy(packetOut+DHCP_MAGIC_COOKIE, dhcpOptions, sizeof(dhcpOptions));
         memcpy(packetOut+DHCP_MAGIC_COOKIE+10, ethernetAddressPlasma, 6);
         request = DHCP_REQUEST;
         packetOut[DHCP_MAGIC_COOKIE+6] = DHCP_REQUEST;
         ptr = packetOut+DHCP_MAGIC_COOKIE+sizeof(dhcpOptions)-1;
         ptr[0] = DHCP_REQUEST_IP;
         ptr[1] = 4;
         memcpy(ptr+2, packet+DHCP_YOUR_IP, 4);
         ptr[6] = DHCP_REQUEST_SERV_IP;
         ptr[7] = 4;
         memcpy(ptr+8, packet+DHCP_SERVER_IP, 4);
         ptr[12] = DHCP_END_OPTION;
         IPSendPacket(NULL, frame, 400);
      }
      else if(packet[DHCP_MAGIC_COOKIE+6] == DHCP_ACK && request == DHCP_REQUEST)
      {
         //Process DHCP Ack
         request = 0;
         DhcpRetrySeconds = 3600*4;
         memcpy(ipAddressPlasma, packet+DHCP_YOUR_IP, 4);
         printf("IP=%d.%d.%d.%d ", ipAddressPlasma[0], ipAddressPlasma[1],
            ipAddressPlasma[2], ipAddressPlasma[3]);
         memcpy(ipAddressGateway, packet+DHCP_GATEWAY_IP, 4);
         if(ipAddressGateway[0] == 0 && ipAddressGateway[1] == 0 &&
            ipAddressGateway[2] == 0 && ipAddressGateway[3] == 0)
            memcpy(ipAddressGateway, packet+DHCP_SERVER_IP, 4);
         printf("GW=%d.%d.%d.%d ", ipAddressGateway[0], ipAddressGateway[1],
            ipAddressGateway[2], ipAddressGateway[3]);
         memcpy(ethernetAddressGateway, packet+ETHERNET_SOURCE, 6);
         ptr2 = packet+DHCP_MAGIC_COOKIE+4;
         while(ptr2[0] != DHCP_END_OPTION && (int)(ptr2 - packet) < length)
         {
            if(ptr2[0] == DHCP_PARAM_DNS)
            {
               ipAddressDns = (ptr2[2] << 24) | (ptr2[3] << 16) | (ptr2[4] << 8) | ptr2[5];
               printf("DNS=%d.%d.%d.%d ", ptr2[2], ptr2[3], ptr2[4], ptr2[5]);
            }
            ptr2 += ptr2[1] + 2;
         }
 
         //Check if DHCP reply came from gateway
         if(memcmp(packet+IP_SOURCE, ipAddressGateway, 4))
         {
            //Send ARP to gateway
            frame = IPFrameGet(0);
            if(frame == NULL)
               return;
            packetOut = frame->packet;
            memset(packetOut, 0, 512);
            memset(packetOut+ETHERNET_DEST, 0xff, 6);
            memcpy(packetOut+ETHERNET_SOURCE, ethernetAddressPlasma, 6);
            packetOut[ETHERNET_FRAME_TYPE] = 0x08;
            packetOut[ETHERNET_FRAME_TYPE+1] = 0x06;
            packetOut[ARP_HARD_TYPE+1] = 0x01;
            packetOut[ARP_PROT_TYPE] = 0x08;
            packetOut[ARP_HARD_SIZE] = 0x06;
            packetOut[ARP_PROT_SIZE] = 0x04;
            packetOut[ARP_OP+1] = 1;
            memcpy(packetOut+ARP_ETHERNET_SENDER, ethernetAddressPlasma, 6);
            memcpy(packetOut+ARP_IP_SENDER, ipAddressPlasma, 4);
            memcpy(packetOut+ARP_IP_TARGET, ipAddressGateway, 4);
            IPSendPacket(NULL, frame, 60);
         }
      }
   }
}
 
 
uint32 IPAddressSelf(void)
{
   return (ipAddressPlasma[0] << 24) | (ipAddressPlasma[1] << 16) |
          (ipAddressPlasma[2] << 8) | ipAddressPlasma[3];
}
 
 
static int IPProcessTCPPacket(IPFrame *frameIn)
{
   uint32 seq, ack;
   int length, ip_length, bytes;
   IPSocket *socket, *socketNew;
   IPFrame *frameOut, *frame2, *framePrev;
   uint8 *packet, *packetOut;
 
   packet = frameIn->packet;
   length = frameIn->length;
 
   ip_length = (packet[IP_LENGTH] << 8) | packet[IP_LENGTH+1];
   seq = (packet[TCP_SEQ] << 24) | (packet[TCP_SEQ+1] << 16) |
         (packet[TCP_SEQ+2] << 8) | packet[TCP_SEQ+3];
   ack = (packet[TCP_ACK] << 24) | (packet[TCP_ACK+1] << 16) |
         (packet[TCP_ACK+2] << 8) | packet[TCP_ACK+3];
 
   //Check if start of connection
   if((packet[TCP_FLAGS] & (TCP_FLAGS_SYN | TCP_FLAGS_ACK)) == TCP_FLAGS_SYN)
   {
      if(IPVerbose)
         printf("S");
      //Check if duplicate SYN
      for(socket = SocketHead; socket; socket = socket->next)
      {
         if(socket->state != IP_LISTEN &&
            packet[IP_PROTOCOL] == socket->headerRcv[IP_PROTOCOL] &&
            memcmp(packet+IP_SOURCE, socket->headerRcv+IP_SOURCE, 8) == 0 &&
            memcmp(packet+TCP_SOURCE_PORT, socket->headerRcv+TCP_SOURCE_PORT, 4) == 0)
         {
            if(IPVerbose)
               printf("s");
            return 0;
         }
      }
 
      //Find an open port
      for(socket = SocketHead; socket; socket = socket->next)
      {
         if(socket->state == IP_LISTEN &&
            packet[IP_PROTOCOL] == socket->headerRcv[IP_PROTOCOL] &&
            memcmp(packet+TCP_DEST_PORT, socket->headerRcv+TCP_DEST_PORT, 2) == 0)
         {
            //Create a new socket
            frameOut = IPFrameGet(FRAME_COUNT_SYNC);
            if(frameOut == NULL)
               return 0;
            socketNew = (IPSocket*)malloc(sizeof(IPSocket));
            if(socketNew == NULL)
               return 0;
            memcpy(socketNew, socket, sizeof(IPSocket));
            socketNew->state = IP_TCP;
            socketNew->timeout = RETRANSMIT_TIME * 3;
            socketNew->ack = seq;
            socketNew->seq = socketNew->ack + 0x12345678;
            socketNew->seqReceived = socketNew->seq;
 
            //Send ACK
            packetOut = frameOut->packet;
            EthernetCreateResponse(packetOut, packet, length);
            memcpy(socketNew->headerRcv, packet, TCP_SEQ);
            memcpy(socketNew->headerSend, packetOut, TCP_SEQ);
            packetOut[TCP_FLAGS] = TCP_FLAGS_SYN | TCP_FLAGS_ACK;
            ++socketNew->ack;
            packetOut[TCP_DATA] = 2;    //maximum segment size = 536
            packetOut[TCP_DATA+1] = 4;
            packetOut[TCP_DATA+2] = 2;
            packetOut[TCP_DATA+3] = 24;
            TCPSendPacket(socketNew, frameOut, TCP_DATA+4);
            ++socketNew->seq;
 
            //Add socket to linked list
            OS_MutexPend(IPMutex);
            socketNew->next = SocketHead;
            socketNew->prev = NULL;
            if(SocketHead)
               SocketHead->prev = socketNew;
            SocketHead = socketNew;
            OS_MutexPost(IPMutex);
            return 0;
         }
      }
      return 0;
   }
 
   //Find an open socket
   for(socket = SocketHead; socket; socket = socket->next)
   {
      if(packet[IP_PROTOCOL] == socket->headerRcv[IP_PROTOCOL] &&
         memcmp(packet+IP_SOURCE, socket->headerRcv+IP_SOURCE, 8) == 0 &&
         memcmp(packet+TCP_SOURCE_PORT, socket->headerRcv+TCP_SOURCE_PORT, 4) == 0)
      {
         break;
      }
   }
   if(socket == NULL)
      return 0;
 
   //Check if FIN flag set
   if(packet[TCP_FLAGS] & TCP_FLAGS_FIN)
   {
      socket->timeout = SOCKET_TIMEOUT;
      if(IPVerbose)
         printf("F");
      frameOut = IPFrameGet(0);
      if(frameOut == NULL)
         return 0;
      packetOut = frameOut->packet;
      packetOut[TCP_FLAGS] = TCP_FLAGS_ACK;
      ++socket->ack;
      TCPSendPacket(socket, frameOut, TCP_DATA);
      if(socket->state == IP_FIN_SERVER)
         IPClose2(socket);
      else
      {
         socket->state = IP_FIN_CLIENT;
         if(socket->funcPtr)
            socket->funcPtr(socket);
      }
   }
   else if(packet[TCP_FLAGS] & TCP_FLAGS_RST)
   {
      if(socket->state == IP_FIN_SERVER)
         IPClose2(socket);
      else
      {
         socket->state = IP_FIN_CLIENT;
         if(socket->funcPtr)
            socket->funcPtr(socket);
      }
   }
   else
   {
      //Check if packets can be removed from retransmition list
      if(ack != socket->seqReceived)
      {
         OS_MutexPend(IPMutex);
         for(frame2 = FrameResendHead; frame2; )
         {
            framePrev = frame2;
            frame2 = frame2->next;
            if(framePrev->socket == socket && (int)(ack - framePrev->seqEnd) >= 0)
            {
               //Remove packet from retransmition queue
               if(socket->timeout)
                  socket->timeout = SOCKET_TIMEOUT;
               FrameRemove(&FrameResendHead, &FrameResendTail, framePrev);
               FrameFree(framePrev);
            }
         }
         OS_MutexPost(IPMutex);
         socket->seqReceived = ack;
      }
 
      bytes = ip_length - (TCP_DATA - IP_VERSION_LENGTH);
 
      //Check if SYN/ACK
      if((packet[TCP_FLAGS] & (TCP_FLAGS_SYN | TCP_FLAGS_ACK)) ==
         (TCP_FLAGS_SYN | TCP_FLAGS_ACK))
      {
         //Ack SYN/ACK
         socket->ack = seq + 1;
         frameOut = IPFrameGet(FRAME_COUNT_SEND);
         if(frameOut)
         {
            frameOut->packet[TCP_FLAGS] = TCP_FLAGS_ACK;
            TCPSendPacket(socket, frameOut, TCP_DATA);
         }
         if(socket->funcPtr)
            socket->funcPtr(socket);
         return 0;
      }
      else if(packet[TCP_HEADER_LENGTH] != 0x50)
      {
         if(IPVerbose)
            printf("length error\n");
         return 0;
      }
 
      //Copy packet into socket
      if(socket->ack == seq && bytes > 0)
      {
         //Insert packet into socket linked list
         if(socket->timeout)
            socket->timeout = SOCKET_TIMEOUT;
         if(IPVerbose)
            printf("D");
         FrameInsert(&socket->frameReadHead, &socket->frameReadTail, frameIn);
         socket->ack += bytes;
 
         //Ack data
         frameOut = IPFrameGet(FRAME_COUNT_SEND);
         if(frameOut)
         {
            frameOut->packet[TCP_FLAGS] = TCP_FLAGS_ACK;
            TCPSendPacket(socket, frameOut, TCP_DATA);
         }
 
         //Determine window
         socket->seqWindow = (packet[TCP_WINDOW_SIZE] << 8) | packet[TCP_WINDOW_SIZE+1];
         if(socket->seqWindow < 8)
            socket->seqWindow = 8;
 
         //Notify application
         if(socket->funcPtr)
            socket->funcPtr(socket);
         //Using frame
         return 1;
      }
 
      if(bytes)
      {
         //Ack with current offset since data missing
         frameOut = IPFrameGet(FRAME_COUNT_SEND);
         if(frameOut)
         {
            frameOut->packet[TCP_FLAGS] = TCP_FLAGS_ACK;
            TCPSendPacket(socket, frameOut, TCP_DATA);
         }
      }
      if(socket->funcPtr)
         socket->funcPtr(socket);
   }
   return 0;
}
 
 
int IPProcessEthernetPacket(IPFrame *frameIn)
{
   int ip_length, rc;
   IPSocket *socket;
   IPFrame *frameOut;
   uint8 *packet, *packetOut;
 
   packet = frameIn->packet;
 
   if(packet[ETHERNET_FRAME_TYPE] != 0x08 || frameIn->length > PACKET_SIZE)
      return 0;  //wrong ethernet type, packet not used
 
   //ARP?
   if(packet[ETHERNET_FRAME_TYPE+1] == 0x06)
   {
      //Check if ARP reply
      if(memcmp(packet+ETHERNET_DEST, ethernetAddressPlasma, 6) == 0 &&
         packet[ARP_OP+1] == 2 && memcmp(packet+ARP_IP_SENDER, ipAddressGateway, 4) == 0)
      {
         //Found MAC address for gateway
         memcpy(ethernetAddressGateway, packet+ARP_ETHERNET_SENDER, 6);
         return 0;
      }
 
      //Check if ARP request
      if(memcmp(packet+ETHERNET_DEST, ethernetAddressNull, 6) ||
         packet[ARP_OP] != 0 || packet[ARP_OP+1] != 1 ||
         memcmp(packet+ARP_IP_TARGET, ipAddressPlasma, 4))
         return 0;
      //Create ARP response
      frameOut = IPFrameGet(0);
      if(frameOut == NULL)
         return 0;
      packetOut = frameOut->packet;
      memcpy(packetOut, packet, frameIn->length);
      memcpy(packetOut+ETHERNET_DEST, packet+ETHERNET_SOURCE, 6);
      memcpy(packetOut+ETHERNET_SOURCE, ethernetAddressPlasma, 6);
      packetOut[ARP_OP+1] = 2; //ARP reply
      memcpy(packetOut+ARP_ETHERNET_SENDER, ethernetAddressPlasma, 6);
      memcpy(packetOut+ARP_IP_SENDER, packet+ARP_IP_TARGET, 4);
      memcpy(packetOut+ARP_ETHERNET_TARGET, packet+ARP_ETHERNET_SENDER, 6);
      memcpy(packetOut+ARP_IP_TARGET, packet+ARP_IP_SENDER, 4);
      IPSendPacket(NULL, frameOut, frameIn->length);
      return 0;
   }
 
   //Check if proper type of packet
   ip_length = (packet[IP_LENGTH] << 8) | packet[IP_LENGTH+1];
   if(frameIn->length < UDP_DATA || ip_length > frameIn->length - IP_VERSION_LENGTH)
      return 0;
   if(packet[ETHERNET_FRAME_TYPE+1] != 0x00 ||
      packet[IP_VERSION_LENGTH] != 0x45)
      return 0;
 
   //Check if DHCP reply
   if(packet[IP_PROTOCOL] == 0x11 &&
      packet[UDP_SOURCE_PORT] == 0 && packet[UDP_SOURCE_PORT+1] == 67 &&
      packet[UDP_DEST_PORT] == 0 && packet[UDP_DEST_PORT+1] == 68)
   {
      IPDhcp(packet, frameIn->length, 2);            //DHCP reply
      return 0;
   }
 
   //Check if correct destination address
   if(memcmp(packet+ETHERNET_DEST, ethernetAddressPlasma, 6) ||
      memcmp(packet+IP_DEST, ipAddressPlasma, 4))
      return 0;
   rc = EthernetVerifyChecksums(packet, frameIn->length);
   //if(rc)
   //{
   //   printf("C ");
   //   return;
   //}
 
   //PING request?
   if(packet[IP_PROTOCOL] == 1)
   {
      if(packet[PING_TYPE] == 0)  //PING reply
      {
         for(socket = SocketHead; socket; socket = socket->next)
         {
            if(socket->state == IP_PING &&
               memcmp(packet+IP_SOURCE, socket->headerSend+IP_DEST, 4) == 0)
            {
               socket->funcPtr(socket);
               return 0;
            }
         }
      }
      if(packet[PING_TYPE] != 8)
         return 0;
      frameOut = IPFrameGet(FRAME_COUNT_SEND);
      if(frameOut == NULL)
         return 0;
      packetOut = frameOut->packet;
      EthernetCreateResponse(packetOut, packet, frameIn->length);
      frameOut->packet[PING_TYPE] = 0;       //PING reply
      IPSendPacket(NULL, frameOut, frameIn->length);
      return 0;
   }
 
   //TCP packet?
   if(packet[IP_PROTOCOL] == 0x06)
   {
      return IPProcessTCPPacket(frameIn);
   }
 
   //UDP packet?
   if(packet[IP_PROTOCOL] == 0x11)
   {
      //Find open socket
      for(socket = SocketHead; socket; socket = socket->next)
      {
         if(packet[IP_PROTOCOL] == socket->headerRcv[IP_PROTOCOL] &&
            memcmp(packet+IP_SOURCE, socket->headerRcv+IP_SOURCE, 8) == 0 &&
            memcmp(packet+UDP_SOURCE_PORT, socket->headerRcv+UDP_SOURCE_PORT, 2) == 0)
         {
            break;
         }
      }
 
      if(socket == NULL)
      {
         //Find listening socket
         for(socket = SocketHead; socket; socket = socket->next)
         {
            if(packet[IP_PROTOCOL] == socket->headerRcv[IP_PROTOCOL] &&
               memcmp(packet+UDP_DEST_PORT, socket->headerRcv+UDP_DEST_PORT, 2) == 0)
            {
               EthernetCreateResponse(socket->headerSend, packet, UDP_DATA);
               break;
            }
         }
      }
 
      if(socket)
      {
         if(IPVerbose)
            printf("U");
         FrameInsert(&socket->frameReadHead, &socket->frameReadTail, frameIn);
         socket->funcPtr(socket);
         return 1;
      }
   }
   return 0;
}
 
 
static void IPMainThread(void *arg)
{
   uint32 message[4];
   int rc;
   IPFrame *frame, *frameOut=NULL;
   uint32 ticks, ticksLast;
   (void)arg;
 
   ticksLast = OS_ThreadTime();
   memset(message, 0, sizeof(message));
 
   for(;;)
   {
      Led(0);
      rc = OS_MQueueGet(IPMQueue, message, 10);
      if(rc == 0)
      {
         frame = (IPFrame*)message[1];
         if(message[0] == 0)       //frame received
         {
            Led(1);
            frame->length = (uint16)message[2];
            rc = IPProcessEthernetPacket(frame);
            if(rc == 0)
               FrameFree(frame);
         }
         else if(message[0] == 1)  //frame sent
         {
            Led(2);
            assert(frame == frameOut);
            IPFrameReschedule(frame);
            frameOut = NULL;
         }
         else if(message[0] == 2)  //frame ready to send
         {
         }
      }
 
      if(frameOut == NULL)
      {
         OS_MutexPend(IPMutex);
         frameOut = FrameSendTail;
         if(frameOut)
            FrameRemove(&FrameSendHead, &FrameSendTail, frameOut);
         OS_MutexPost(IPMutex);
         if(frameOut)
         {
            Led(4);
            UartPacketSend(frameOut->packet, frameOut->length);
         }
      }
 
      ticks = OS_ThreadTime();
      if(ticks - ticksLast > 100)
      {
         IPTick();
         ticksLast = ticks;
      }
   }
}
 
 
uint8 *MyPacketGet(void)
{
   return (uint8*)IPFrameGet(FRAME_COUNT_RCV);
}
 
 
//Set FrameSendFunction only if single threaded
void IPInit(IPFuncPtr frameSendFunction)
{
   int i;
   IPFrame *frame;
 
   FrameSendFunc = frameSendFunction;
   IPMutex = OS_MutexCreate("IPSem");
   IPMQueue = OS_MQueueCreate("IPMQ", FRAME_COUNT*2, 32);
   for(i = 0; i < FRAME_COUNT; ++i)
   {
      frame = (IPFrame*)malloc(sizeof(IPFrame));
      memset(frame, 0, sizeof(IPFrame));
      frame->next = FrameFreeHead;
      frame->prev = NULL;
      FrameFreeHead = frame;
   }
   UartPacketConfig(MyPacketGet, PACKET_SIZE, IPMQueue);
   if(frameSendFunction == NULL)
      IPThread = OS_ThreadCreate("TCP/IP", IPMainThread, NULL, 240, 6000);
 
   IPDhcp(NULL, 360, 1);        //Send DHCP request
}
 
 
//To open a socket for listen set ipAddress to 0
IPSocket *IPOpen(IPMode_e mode, uint32 ipAddress, uint32 port, IPFuncPtr funcPtr)
{
   IPSocket *socket;
   uint8 *ptrSend, *ptrRcv;
   IPFrame *frame;
   static int portSource=0x1007;
 
   socket = (IPSocket*)malloc(sizeof(IPSocket));
   if(socket == NULL)
      return socket;
   memset(socket, 0, sizeof(IPSocket));
   socket->prev = NULL;
   socket->state = IP_LISTEN;
   socket->timeout = 0;
   socket->frameReadHead = NULL;
   socket->frameReadTail = NULL;
   socket->readOffset = 0;
   socket->funcPtr = funcPtr;
   socket->userData = 0;
   socket->userFunc = NULL;
   socket->userPtr = NULL;
   ptrSend = socket->headerSend;
   ptrRcv = socket->headerRcv;
 
   if(ipAddress == 0)
   {
      //Setup listing port
      socket->headerRcv[TCP_DEST_PORT] = (uint8)(port >> 8);
      socket->headerRcv[TCP_DEST_PORT+1] = (uint8)port;
   }
   else
   {
      //Setup sending packet
      memset(ptrSend, 0, UDP_LENGTH);
      memset(ptrRcv, 0, UDP_LENGTH);
 
      //Setup Ethernet
      if(ipAddress != IPAddressSelf())
         memcpy(ptrSend+ETHERNET_DEST, ethernetAddressGateway, 6);
      else
         memcpy(ptrSend+ETHERNET_DEST, ethernetAddressPlasma, 6);
      memcpy(ptrSend+ETHERNET_SOURCE, ethernetAddressPlasma, 6);
      ptrSend[ETHERNET_FRAME_TYPE] = 0x08;
 
      //Setup IP
      ptrSend[IP_VERSION_LENGTH] = 0x45;
      ptrSend[IP_TIME_TO_LIVE] = 0x80;
 
      //Setup IP addresses
      memcpy(ptrSend+IP_SOURCE, ipAddressPlasma, 4);
      ptrSend[IP_DEST] = (uint8)(ipAddress >> 24);
      ptrSend[IP_DEST+1] = (uint8)(ipAddress >> 16);
      ptrSend[IP_DEST+2] = (uint8)(ipAddress >> 8);
      ptrSend[IP_DEST+3] = (uint8)ipAddress;
      ptrRcv[IP_SOURCE] = (uint8)(ipAddress >> 24);
      ptrRcv[IP_SOURCE+1] = (uint8)(ipAddress >> 16);
      ptrRcv[IP_SOURCE+2] = (uint8)(ipAddress >> 8);
      ptrRcv[IP_SOURCE+3] = (uint8)ipAddress;
      memcpy(ptrRcv+IP_DEST, ipAddressPlasma, 4);
 
      //Setup ports
      ptrSend[TCP_SOURCE_PORT] = (uint8)(portSource >> 8);
      ptrSend[TCP_SOURCE_PORT+1] = (uint8)portSource;
      ptrSend[TCP_DEST_PORT] = (uint8)(port >> 8);
      ptrSend[TCP_DEST_PORT+1] = (uint8)port;
      ptrRcv[TCP_SOURCE_PORT] = (uint8)(port >> 8);
      ptrRcv[TCP_SOURCE_PORT+1] = (uint8)port;
      ptrRcv[TCP_DEST_PORT] = (uint8)(portSource >> 8);
      ptrRcv[TCP_DEST_PORT+1] = (uint8)portSource;
      ++portSource;
   }
 
   if(mode == IP_MODE_TCP)
   {
      if(ipAddress)
         socket->state = IP_TCP;
      else
         socket->state = IP_LISTEN;
      ptrSend[IP_PROTOCOL] = 0x06;  //TCP
      ptrRcv[IP_PROTOCOL] = 0x06;
   }
   else if(mode == IP_MODE_UDP)
   {
      socket->state = IP_UDP;
      ptrSend[IP_PROTOCOL] = 0x11;  //UDP
      ptrRcv[IP_PROTOCOL] = 0x11;
   }
   else if(mode == IP_MODE_PING)
   {
      socket->state = IP_PING;
      ptrSend[IP_PROTOCOL] = 0x01;  //PING
      memset(ptrSend+PING_TYPE, 0, 8);
      ptrSend[PING_TYPE] = 8;       //SEND
   }
 
   //Add socket to linked list
   OS_MutexPend(IPMutex);
   socket->next = SocketHead;
   socket->prev = NULL;
   if(SocketHead)
      SocketHead->prev = socket;
   SocketHead = socket;
   OS_MutexPost(IPMutex);
 
   if(mode == IP_MODE_TCP && ipAddress)
   {
      //Send TCP SYN
      socket->seq = 0x01234567;
      frame = IPFrameGet(0);
      if(frame)
      {
         frame->packet[TCP_FLAGS] = TCP_FLAGS_SYN;
         frame->packet[TCP_DATA] = 2;    //maximum segment size = 536
         frame->packet[TCP_DATA+1] = 4;
         frame->packet[TCP_DATA+2] = 2;
         frame->packet[TCP_DATA+3] = 24;
         TCPSendPacket(socket, frame, TCP_DATA+4);
         ++socket->seq;
      }
   }
   return socket;
}
 
 
void IPWriteFlush(IPSocket *socket)
{
   uint8 *packetOut;
   if(socket->frameSend && socket->state != IP_UDP &&
      socket->state != IP_PING)
   {
      packetOut = socket->frameSend->packet;
      packetOut[TCP_FLAGS] = TCP_FLAGS_ACK;
      TCPSendPacket(socket, socket->frameSend, TCP_DATA + socket->sendOffset);
      socket->seq += socket->sendOffset;
      socket->frameSend = NULL;
      socket->sendOffset = 0;
   }
}
 
 
uint32 IPWrite(IPSocket *socket, const uint8 *buf, uint32 length)
{
   IPFrame *frameOut;
   uint8 *packetOut;
   uint32 bytes, count=0, tries=0;
   int offset;
   OS_Thread_t *self;
 
   //printf("IPWrite(0x%x, %d)", Socket, Length);
   self = OS_ThreadSelf();
   while(length)
   {
      //Rate limit output
      if(socket->seq - socket->seqReceived >= 5120)
      {
         if(self == IPThread || ++tries > 200)
            break;
         else
         {
            OS_ThreadSleep(1);
            continue;
         }
      }
      tries = 0;
      while(socket->frameSend == NULL)
      {
         socket->frameSend = IPFrameGet(FRAME_COUNT_SEND);
         socket->sendOffset = 0;
         if(socket->frameSend == NULL)
         {
            if(self == IPThread || ++tries > 200)
               break;
            else
               OS_ThreadSleep(1);
         }
      }
      frameOut = socket->frameSend;
      offset = socket->sendOffset;
      if(frameOut == NULL)
         break;
      packetOut = frameOut->packet;
 
      if(socket->state == IP_PING)
      {
         bytes = length;
         memcpy(packetOut, socket->headerSend, PING_DATA);
         memcpy(packetOut+PING_DATA, buf, bytes);
         IPSendPacket(socket, socket->frameSend, PING_DATA + bytes);
         socket->frameSend = NULL;
      }
      else if(socket->state != IP_UDP)
      {
         bytes = 512 - offset;
         if(bytes > length)
            bytes = length;
         socket->sendOffset += bytes;
         memcpy(packetOut+TCP_DATA+offset, buf, bytes);
         if(socket->sendOffset >= 512)
            IPWriteFlush(socket);
         //if(Socket->seq - Socket->seqReceived > Socket->seqWindow)
         //{
         //   printf("W");
         //   OS_ThreadSleep(10);
         //}
      }
      else  //UDP
      {
         bytes = length;
         memcpy(packetOut+UDP_DATA+offset, buf, bytes);
         memcpy(packetOut, socket->headerSend, UDP_LENGTH);
         IPSendPacket(socket, socket->frameSend, UDP_DATA + bytes);
         socket->frameSend = NULL;
      }
      count += bytes;
      buf += bytes;
      length -= bytes;
   }
   return count;
}
 
 
uint32 IPRead(IPSocket *socket, uint8 *buf, uint32 length)
{
   IPFrame *frame, *frame2;
   int count=0, bytes, offset;
 
   if(socket->state == IP_TCP)
      offset = TCP_DATA;
   else
      offset = UDP_DATA;
 
   OS_MutexPend(IPMutex);
   for(frame = socket->frameReadTail; length && frame; )
   {
      bytes = frame->length - offset - socket->readOffset;
      if(bytes > (int)length)
         bytes = length;
      memcpy(buf, frame->packet + offset + socket->readOffset, bytes);
      buf += bytes;
      socket->readOffset += bytes;
      length -= bytes;
      count += bytes;
 
      //Check if done with packet
      frame2 = frame;
      frame = frame->prev;
      if(socket->readOffset == frame2->length - offset)
      {
         //Remove packet from socket linked list
         socket->readOffset = 0;
         FrameRemove(&socket->frameReadHead, &socket->frameReadTail, frame2);
         FrameFree(frame2);
      }
   }
   OS_MutexPost(IPMutex);
   return count;
}
 
 
static void IPClose2(IPSocket *socket)
{
   IPFrame *frame, *framePrev;
 
   OS_MutexPend(IPMutex);
 
   //Mark packets as don't retransmit
   for(frame = FrameSendHead; frame; frame = frame->next)
   {
      if(frame->socket == socket)
         frame->socket = NULL;
   }
 
   //Remove packets from retransmision list
   for(frame = FrameResendHead; frame; )
   {
      framePrev = frame;
      frame = frame->next;
      if(framePrev->socket == socket)
      {
         FrameRemove(&FrameResendHead, &FrameResendTail, framePrev);
         FrameFree(framePrev);
      }
   }
 
   //Remove packets from socket read linked list
   for(frame = socket->frameReadHead; frame; )
   {
      framePrev = frame;
      frame = frame->next;
      FrameRemove(&socket->frameReadHead, &socket->frameReadTail, framePrev);
      FrameFree(framePrev);
   }
 
   //Remove socket
   if(socket->prev == NULL)
      SocketHead = socket->next;
   else
      socket->prev->next = socket->next;
   if(socket->next)
      socket->next->prev = socket->prev;
   free(socket);
   OS_MutexPost(IPMutex);
}
 
 
void IPClose(IPSocket *socket)
{
   IPFrame *frameOut;
 
   IPWriteFlush(socket);
   if(socket->state <= IP_UDP)
   {
      IPClose2(socket);
      return;
   }
   frameOut = IPFrameGet(0);
   if(frameOut == 0)
      return;
   frameOut->packet[TCP_FLAGS] = TCP_FLAGS_FIN | TCP_FLAGS_ACK;
   TCPSendPacket(socket, frameOut, TCP_DATA);
   ++socket->seq;
   if(socket->state == IP_FIN_CLIENT)
      IPClose2(socket);
   else
      socket->state = IP_FIN_SERVER;
}
 
 
void IPPrintf(IPSocket *socket, char *message)
{
   IPWrite(socket, (uint8*)message, (int)strlen(message));
   IPWriteFlush(socket);
}
 
 
void IPTick(void)
{
   IPFrame *frame, *frame2;
   IPSocket *socket, *socket2;
 
   if(IPVerbose && (Seconds % 60) == 0)
   {
      if(FrameFreeCount == FRAME_COUNT)
         printf("T");
      else
         printf("T(%d)", FrameFreeCount);
   }
   ++Seconds;
   if(--DhcpRetrySeconds <= 0)
      IPDhcp(NULL, 400, 1);   //DHCP request
   //if(Seconds == 10)
   //   IPResolve("plasmacpu.no-ip.org", ShowIP);
 
   OS_MutexPend(IPMutex);
 
   //Retransmit timeout packets
   for(frame = FrameResendHead; frame; )
   {
      frame2 = frame;
      frame = frame->next;
      if(--frame2->timeout == 0)
      {
         if(IPVerbose)
            printf("r");
         FrameRemove(&FrameResendHead, &FrameResendTail, frame2);
         IPSendFrame(frame2);
      }
   }
 
   //Close timed out sockets
   for(socket = SocketHead; socket; )
   {
      socket2 = socket;
      socket = socket->next;
      if(socket2->timeout && --socket2->timeout == 0)
      {
         socket2->timeout = 10;
         if(IPVerbose)
            printf("t(%d,%d)", socket2->state, FrameFreeCount);
         if(socket2->state == IP_TCP)
            IPClose(socket2);
         else if(socket2->state == IP_FIN_CLIENT)
            IPClose(socket2);
         else
            IPClose2(socket2);
      }
   }
   OS_MutexPost(IPMutex);
}
 
 
static void DnsCallback(IPSocket *socket)
{
   uint8 buf[200], *ptr;
   uint32 ipAddress;
   int bytes;
 
   memset(buf, 0, sizeof(buf));
   bytes = IPRead(socket, buf, sizeof(buf));
   if(buf[DNS_NUM_ANSWERS_RR+1])
   {
      for(ptr = buf + DNS_QUESTIONS; ptr + 14 <= buf + bytes; ++ptr)
      {
         if(ptr[0] == 0 && ptr[1] == 1 && ptr[2] == 0 && ptr[3] == 1 &&
            ptr[8] == 0 && ptr[9] == 4)
         {
            ipAddress = (ptr[10] << 24) | (ptr[11] << 16) | (ptr[12] << 8) | ptr[13];
            printf("ipAddress = %d.%d.%d.%d\n", ptr[10], ptr[11], ptr[12], ptr[13]);
            socket->userData = ipAddress;
            if(socket->userFunc)
            {
               socket->userFunc(socket, ipAddress, socket->userPtr);
            }
            break;
         }
      }
   }
   if(FrameSendFunc)
      IPClose(socket);
}
 
 
uint32 IPResolve(char *name, IPFuncPtr resolvedFunc, void *arg)
{
   uint8 buf[200], *ptr;
   int length, i;
   IPSocket *socket;
   uint32 ipAddress=0;
 
   socket = IPOpen(IP_MODE_UDP, ipAddressDns, DNS_PORT, DnsCallback);
   memset(buf, 0, sizeof(buf));
   buf[DNS_ID+1] = 1;
   buf[DNS_FLAGS] = 1;
   buf[DNS_NUM_QUESTIONS+1] = 1;
 
   //Setup name
   ptr = buf + DNS_QUESTIONS;
   strncpy((char*)ptr+1, name, 100);
   ptr[0] = 1;
   while(ptr[0])
   {
      for(i = 0; i < 100; ++i)
      {
         if(ptr[i+1] == '.' || ptr[i+1] == 0)
         {
            ptr[0] = (uint8)i;
            ptr += i+1;
            break;
         }
      }
   }
   ++ptr;
   ptr[1] = DNS_QUERY_TYPE_IP;
   ptr[3] = DNS_QUERY_CLASS;
   length = (int)(ptr - buf) + 4;
   if(length < 60)
      length = 60;
 
   socket->userFunc = (IPFuncPtr)resolvedFunc;
   socket->userPtr = arg;
   socket->userData = 0;
   IPWrite(socket, buf, length);
 
   if(FrameSendFunc == NULL)
   {
      for(i = 0; i < 1000 && socket->userData == 0; ++i)
         OS_ThreadSleep(1);
      ipAddress = socket->userData;
      IPClose(socket);
   }
   return ipAddress;
}
 

Line No.	Rev	Author	Line
1	155	rhoads	`/*--------------------------------------------------------------------`
2			`* TITLE: Plasma TCP/IP Protocol Stack`
3			`* AUTHOR: Steve Rhoads (rhoadss@yahoo.com)`
4			`* DATE CREATED: 4/22/06`
5			`* FILENAME: tcpip.c`
6			`* PROJECT: Plasma CPU core`
7			`* COPYRIGHT: Software placed into the public domain by the author.`
8			`* Software 'as is' without warranty. Author liable for nothing.`
9			`* DESCRIPTION:`
10			`* Plasma TCP/IP Protocol Stack`
11			`*`
12			`* Possible call stack when receiving a packet:`
13			`* IPMainThread()`
14			`* IPProcessEthernetPacket()`
15			`* IPProcessTCPPacket()`
16			`* TCPSendPacket()`
17			`* IPSendPacket()`
18			`* IPChecksum()`
19			`* IPSendFrame()`
20			`* FrameInsert()`
21			`--------------------------------------------------------------------/`
22			`#ifdef WIN32`
23			`#include <stdio.h>`
24			`#include <stdlib.h>`
25			`#include <string.h>`
26			`#include <assert.h>`
27			`#define _LIBC`
28			`#endif`
29			`#include "rtos.h"`
30			`#include "tcpip.h"`
31
32			`#ifdef WIN32`
33			`#undef OS_CriticalBegin`
34			`#undef OS_CriticalEnd`
35			`#define OS_CriticalBegin() 0`
36			`#define OS_CriticalEnd(A)`
37			`#define OS_ThreadCreate(A,B,C,D,E) 0`
38			`#define OS_ThreadSleep(A)`
39			`#define OS_ThreadTime() 0`
40	157	rhoads	`#define OS_ThreadSelf() 0`
41			`#define OS_MutexCreate(A) NULL`
42			`#define OS_MutexPend(A)`
43			`#define OS_MutexPost(A)`
44	155	rhoads	`#define OS_MQueueCreate(A,B,C) 0`
45			`#define OS_MQueueSend(A,B) 0`
46			`#define OS_MQueueGet(A,B,C) 0`
47			`#define UartPacketConfig(A,B,C)`
48			`#define UartPacketSend(A,B)`
49			`#define UartPrintf printf`
50			`#define UartPrintfCritical printf`
51			`#define Led(A)`
52			`#endif`
53
54			`//ETHER FIELD OFFSET LENGTH VALUE`
55			`#define ETHERNET_DEST 0 //6`
56			`#define ETHERNET_SOURCE 6 //6`
57			`#define ETHERNET_FRAME_TYPE 12 //2 IP=0x0800; ARP=0x0806`
58
59			`//ARP FIELD OFFSET LENGTH VALUE`
60			`#define ARP_HARD_TYPE 14 //2 0x0001`
61			`#define ARP_PROT_TYPE 16 //2 0x0800`
62			`#define ARP_HARD_SIZE 18 //1 0x06`
63			`#define ARP_PROT_SIZE 19 //1 0x04`
64			`#define ARP_OP 20 //2 ARP=1;ARPreply=2`
65			`#define ARP_ETHERNET_SENDER 22 //6`
66			`#define ARP_IP_SENDER 28 //4`
67			`#define ARP_ETHERNET_TARGET 32 //6`
68			`#define ARP_IP_TARGET 38 //4`
69			`#define ARP_PAD 42 //18 0`
70
71			`//IP FIELD OFFSET LENGTH VALUE`
72			`#define IP_VERSION_LENGTH 14 //1 0x45`
73			`#define IP_TYPE_OF_SERVICE 15 //1 0x00`
74			`#define IP_LENGTH 16 //2`
75			`#define IP_ID16 18 //2`
76			`#define IP_FRAG_OFFSET 20 //2`
77			`#define IP_TIME_TO_LIVE 22 //1 0x80`
78			`#define IP_PROTOCOL 23 //1 TCP=0x06;PING=0x01;UDP=0x11`
79			`#define IP_CHECKSUM 24 //2`
80			`#define IP_SOURCE 26 //4`
81			`#define IP_DEST 30 //4`
82
83			`//PSEUDO FIELD OFFSET LENGTH VALUE`
84			`#define PSEUDO_IP_SOURCE 0 //4`
85			`#define PSEUDO_IP_DEST 4 //4`
86			`#define PSEUDO_ZERO 8 //1 0`
87			`#define PSEUDO_IP_PROTOCOL 9 //1`
88			`#define PSEUDO_LENGTH 10 //2`
89
90			`//UDP FIELD OFFSET LENGTH VALUE`
91			`#define UDP_SOURCE_PORT 34 //2`
92			`#define UDP_DEST_PORT 36 //2`
93			`#define UDP_LENGTH 38 //2`
94			`#define UDP_CHECKSUM 40 //2`
95			`#define UDP_DATA 42`
96
97			`//DHCP FIELD OFFSET LENGTH VALUE`
98			`#define DHCP_OPCODE 42 //1 REQUEST=1;REPLY=2`
99			`#define DHCP_HW_TYPE 43 //1 1`
100			`#define DHCP_HW_LEN 44 //1 6`
101			`#define DHCP_HOP_COUNT 45 //1 0`
102			`#define DHCP_TRANS_ID 46 //4`
103			`#define DHCP_NUM_SEC 50 //2 0`
104			`#define DHCP_UNUSED 52 //2`
105			`#define DHCP_CLIENT_IP 54 //4`
106			`#define DHCP_YOUR_IP 58 //4`
107			`#define DHCP_SERVER_IP 62 //4`
108			`#define DHCP_GATEWAY_IP 66 //4`
109			`#define DHCP_CLIENT_ETHERNET 70 //16`
110			`#define DHCP_SERVER_NAME 86 //64`
111			`#define DHCP_BOOT_FILENAME 150 //128`
112			`#define DHCP_MAGIC_COOKIE 278 //4 0x63825363`
113			`#define DHCP_OPTIONS 282 //N`
114
115			`#define DHCP_MESSAGE_TYPE 53 //1 type`
116			`#define DHCP_DISCOVER 1`
117			`#define DHCP_OFFER 2`
118			`#define DHCP_REQUEST 3`
119			`#define DHCP_ACK 5`
120			`#define DHCP_REQUEST_IP 50 //4 ip`
121			`#define DHCP_REQUEST_SERV_IP 54 //4 ip`
122			`#define DHCP_CLIENT_ID 61 //7 1 ethernet`
123			`#define DHCP_HOST_NAME 12 //6 plasma`
124			`#define DHCP_PARAMS 55 //4 1=subnet; 15=domain_name; 3=router; 6=dns`
125			`#define DHCP_PARAM_SUBNET 1`
126			`#define DHCP_PARAM_ROUTER 3`
127			`#define DHCP_PARAM_DNS 6`
128			`#define DHCP_END_OPTION 0xff`
129
130			`//DHCP FIELD OFFSET LENGTH VALUE`
131	206	rhoads	`#define DNS_ID 0 //2`
132			`#define DNS_FLAGS 2 //2`
133			`#define DNS_NUM_QUESTIONS 4 //2 1`
134			`#define DNS_NUM_ANSWERS_RR 6 //2 0/1`
135			`#define DNS_NUM_AUTHORITY_RR 8 //2 0`
136	155	rhoads	`#define DNS_NUM_ADDITIONAL_RR 10 //2 0`
137			`#define DNS_QUESTIONS 12 //2`
138
139			`#define DNS_FLAGS_RESPONSE 0x8000`
140			`#define DNS_FLAGS_RECURSIVE 0x0100`
141			`#define DNS_FLAGS_ERROR 0x0003`
142			`#define DNS_FLAGS_OK 0x0000`
143			`#define DNS_QUERY_TYPE_IP 1`
144			`#define DNS_QUERY_CLASS 1`
145			`#define DNS_PORT 53`
146
147			`//TCP FIELD OFFSET LENGTH VALUE`
148			`#define TCP_SOURCE_PORT 34 //2`
149			`#define TCP_DEST_PORT 36 //2`
150			`#define TCP_SEQ 38 //4`
151			`#define TCP_ACK 42 //4`
152			`#define TCP_HEADER_LENGTH 46 //1 0x50`
153			`#define TCP_FLAGS 47 //1 SYNC=0x2;ACK=0x10;FIN=0x1`
154			`#define TCP_WINDOW_SIZE 48 //2`
155			`#define TCP_CHECKSUM 50 //2`
156			`#define TCP_URGENT_POINTER 52 //2`
157			`#define TCP_DATA 54 //length-N`
158
159			`#define TCP_FLAGS_FIN 1`
160			`#define TCP_FLAGS_SYN 2`
161			`#define TCP_FLAGS_RST 4`
162	209	rhoads	`#define TCP_FLAGS_PSH 8`
163	155	rhoads	`#define TCP_FLAGS_ACK 16`
164
165			`//PING FIELD OFFSET LENGTH VALUE`
166			`#define PING_TYPE 34 //1 SEND=8;REPLY=0`
167			`#define PING_CODE 35 //1 0`
168			`#define PING_CHECKSUM 36 //2`
169			`#define PING_ID 38 //2`
170			`#define PING_SEQUENCE 40 //2`
171			`#define PING_DATA 44`
172
173			`static void IPClose2(IPSocket *Socket);`
174
175			`static uint8 ethernetAddressNull[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};`
176	206	rhoads	`static uint8 ethernetAddressGateway[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};`
177			`#ifndef WIN32`
178	155	rhoads	`static uint8 ethernetAddressPlasma[] = {0x00, 0x10, 0xdd, 0xce, 0x15, 0xd4};`
179	206	rhoads	`#else`
180			`static uint8 ethernetAddressPlasma[] = {0x00, 0x10, 0xdd, 0xce, 0x15, 0xd5};`
181			`#endif`
182	155	rhoads
183			`static uint8 ipAddressPlasma[] = {0x9d, 0xfe, 0x28, 10}; //changed by DHCP`
184			`static uint8 ipAddressGateway[] = {0xff, 0xff, 0xff, 0xff}; //changed by DHCP`
185			`static uint32 ipAddressDns; //changed by DHCP`
186
187	157	rhoads	`static OS_Mutex_t *IPMutex;`
188	155	rhoads	`static int FrameFreeCount=FRAME_COUNT;`
189			`static IPFrame *FrameFreeHead;`
190			`static IPFrame *FrameSendHead;`
191			`static IPFrame *FrameSendTail;`
192			`static IPFrame *FrameResendHead;`
193			`static IPFrame *FrameResendTail;`
194			`static IPSocket *SocketHead;`
195			`static uint32 Seconds;`
196			`static int DhcpRetrySeconds;`
197			`static IPFuncPtr FrameSendFunc;`
198			`static OS_MQueue_t *IPMQueue;`
199	157	rhoads	`static OS_Thread_t *IPThread;`
200	155	rhoads	`int IPVerbose=1;`
201
202			`static const unsigned char dhcpDiscover[] = {`
203			`0xff, 0xff, 0xff, 0xff, 0xff, 0xff, //dest`
204			`0x00, 0x10, 0xdd, 0xce, 0x15, 0xd4, //src`
205			`0x08, 0x00,`
206			`0x45, 0x00, 0x01, 0x48, 0x2e, 0xf5, 0x00, 0x00, //ip`
207			`0x80, 0x11, 0x0a, 0xb1, 0x00, 0x00, 0x00, 0x00,`
208			`0xff, 0xff, 0xff, 0xff,`
209			`0x00, 0x44, 0x00, 0x43, 0x01, 0x34, 0x45, 0x66, //udp`
210			`0x01, 0x01, 0x06, 0x00, 0x69, 0x26, 0xb5, 0x52 //dhcp`
211			`};`
212
213			`static const unsigned char dhcpOptions[] = {`
214			`0x63, 0x82, 0x53, 0x63, //cookie`
215			`0x35, 0x01, 0x01, //DHCP Discover`
216			`0x3d, 0x07, 0x01, 0x00, 0x10, 0xdd, 0xce, 0x15, 0xd4, //Client identifier`
217	206	rhoads	`#ifndef WIN32`
218	155	rhoads	`0x0c, 0x06, 'p', 'l', 'a', 's', 'm', 'a', //Host name`
219	206	rhoads	`#else`
220			`0x0c, 0x06, 'p', 'l', 'a', 's', 'm', 'b', //Host name`
221			`#endif`
222	155	rhoads	`0x37, 0x03, DHCP_PARAM_SUBNET, DHCP_PARAM_ROUTER, DHCP_PARAM_DNS, //Parameters`
223			`DHCP_END_OPTION`
224			`};`
225
226
227			`//Get a free frame; can be called from an ISR`
228	157	rhoads	`IPFrame *IPFrameGet(int freeCount)`
229	155	rhoads	`{`
230			`IPFrame *frame=NULL;`
231			`uint32 state;`
232	157	rhoads
233			`state = OS_CriticalBegin();`
234			`if(FrameFreeCount > freeCount)`
235	155	rhoads	`{`
236	157	rhoads	`--FrameFreeCount;`
237			`frame = FrameFreeHead;`
238			`if(FrameFreeHead)`
239			`FrameFreeHead = FrameFreeHead->next;`
240	155	rhoads	`}`
241	157	rhoads	`OS_CriticalEnd(state);`
242	155	rhoads	`if(frame)`
243			`{`
244	157	rhoads	`assert(frame->state == 0);`
245			`frame->state = 1;`
246	155	rhoads	`}`
247			`return frame;`
248			`}`
249
250
251			`static void FrameFree(IPFrame *frame)`
252			`{`
253			`uint32 state;`
254
255			`assert(frame->state == 1);`
256			`frame->state = 0;`
257			`state = OS_CriticalBegin();`
258			`frame->next = FrameFreeHead;`
259			`FrameFreeHead = frame;`
260			`++FrameFreeCount;`
261			`OS_CriticalEnd(state);`
262			`}`
263
264
265			`static void FrameInsert(IPFrame head, IPFrame tail, IPFrame *frame)`
266			`{`
267			`assert(frame->state == 1);`
268			`frame->state = 2;`
269	157	rhoads	`OS_MutexPend(IPMutex);`
270	155	rhoads	`frame->prev = NULL;`
271			`frame->next = *head;`
272			`if(*head)`
273			`(*head)->prev = frame;`
274			`*head = frame;`
275			`if(*tail == NULL)`
276			`*tail = frame;`
277	157	rhoads	`OS_MutexPost(IPMutex);`
278	155	rhoads	`}`
279
280
281			`static void FrameRemove(IPFrame head, IPFrame tail, IPFrame *frame)`
282			`{`
283			`assert(frame->state == 2);`
284			`frame->state = 1;`
285			`if(frame->prev)`
286			`frame->prev->next = frame->next;`
287			`else`
288			`*head = frame->next;`
289			`if(frame->next)`
290			`frame->next->prev = frame->prev;`
291			`else`
292			`*tail = frame->prev;`
293			`frame->prev = NULL;`
294			`frame->next = NULL;`
295			`}`
296
297
298			`static int IPChecksum(int checksum, const unsigned char *data, int length)`
299			`{`
300			`int i;`
301			`checksum = ~checksum & 0xffff;`
302			`for(i = 0; i < length-1; i += 2)`
303			`{`
304			`checksum += (data[i] << 8) \| data[i+1];`
305			`}`
306			`if(i < length)`
307			`checksum += data[i] << 8;`
308			`while(checksum >> 16)`
309			`checksum = (checksum & 0xffff) + (checksum >> 16);`
310			`checksum = ~checksum & 0xffff;`
311			`return checksum;`
312			`}`
313
314
315			`static int EthernetVerifyChecksums(const unsigned char *packet, int length)`
316			`{`
317			`int checksum, length2;`
318			`unsigned char pseudo[12];`
319
320			`//Calculate checksums`
321			`if(packet[ETHERNET_FRAME_TYPE+1] == 0x00) //IP`
322			`{`
323			`checksum = IPChecksum(0xffff, packet+IP_VERSION_LENGTH, 20);`
324			`if(checksum)`
325			`return -1;`
326			`if(packet[IP_PROTOCOL] == 0x01) //PING`
327			`{`
328			`checksum = IPChecksum(0xffff, packet+PING_TYPE, length-PING_TYPE);`
329			`}`
330			`else if(packet[IP_PROTOCOL] == 0x11) //UDP`
331			`{`
332			`if(packet[UDP_CHECKSUM] == 0 && packet[UDP_CHECKSUM+1] == 0)`
333			`return 0;`
334			`memcpy(pseudo+PSEUDO_IP_SOURCE, packet+IP_SOURCE, 4);`
335			`memcpy(pseudo+PSEUDO_IP_DEST, packet+IP_DEST, 4);`
336			`pseudo[PSEUDO_ZERO] = 0;`
337			`pseudo[PSEUDO_IP_PROTOCOL] = packet[IP_PROTOCOL];`
338			`memcpy(pseudo+PSEUDO_LENGTH, packet+UDP_LENGTH, 2);`
339			`checksum = IPChecksum(0xffff, pseudo, 12);`
340			`length2 = (packet[UDP_LENGTH] << 8) + packet[UDP_LENGTH+1];`
341			`checksum = IPChecksum(checksum, packet+UDP_SOURCE_PORT, length);`
342			`}`
343			`else if(packet[IP_PROTOCOL] == 0x06) //TCP`
344			`{`
345			`memcpy(pseudo+PSEUDO_IP_SOURCE, packet+IP_SOURCE, 4);`
346			`memcpy(pseudo+PSEUDO_IP_DEST, packet+IP_DEST, 4);`
347			`pseudo[PSEUDO_ZERO] = 0;`
348			`pseudo[PSEUDO_IP_PROTOCOL] = packet[IP_PROTOCOL];`
349			`length = (packet[IP_LENGTH] << 8) + packet[IP_LENGTH+1];`
350			`length2 = length - 20;`
351			`pseudo[PSEUDO_LENGTH] = (unsigned char)(length2 >> 8);`
352			`pseudo[PSEUDO_LENGTH+1] = (unsigned char)length2;`
353			`checksum = IPChecksum(0xffff, pseudo, 12);`
354			`checksum = IPChecksum(checksum, packet+TCP_SOURCE_PORT, length2);`
355			`}`
356			`if(checksum)`
357			`return -1;`
358			`}`
359			`return 0;`
360			`}`
361
362
363			`static void IPFrameReschedule(IPFrame *frame)`
364			`{`
365			`int length;`
366			`length = frame->length - TCP_DATA;`
367	160	rhoads	`if(frame->packet[TCP_FLAGS] & (TCP_FLAGS_FIN \| TCP_FLAGS_SYN))`
368	155	rhoads	`++length;`
369			`if(frame->socket == NULL \|\| frame->socket->state == IP_UDP \|\| length == 0 \|\|`
370	209	rhoads	`frame->socket->state == IP_PING \|\| ++frame->retryCnt > 4)`
371	155	rhoads	`{`
372			`FrameFree(frame); //can't be ACK'ed`
373			`}`
374			`else`
375			`{`
376			`//Put on resend list until TCP ACK'ed`
377			`frame->timeout = RETRANSMIT_TIME;`
378			`FrameInsert(&FrameResendHead, &FrameResendTail, frame);`
379			`}`
380			`}`
381
382
383			`static void IPSendFrame(IPFrame *frame)`
384			`{`
385			`uint32 message[4];`
386
387			`if(FrameSendFunc)`
388			`{`
389			`//Single threaded`
390			`FrameSendFunc(frame->packet, frame->length);`
391			`IPFrameReschedule(frame);`
392			`}`
393			`else`
394			`{`
395			`//Add Packet to send queue`
396			`FrameInsert(&FrameSendHead, &FrameSendTail, frame);`
397
398			`//Wakeup sender thread`
399			`message[0] = 2;`
400			`OS_MQueueSend(IPMQueue, message);`
401			`}`
402			`}`
403
404
405			`static void IPSendPacket(IPSocket socket, IPFrame frame, int length)`
406			`{`
407			`int checksum, length2=length;`
408			`unsigned char pseudo[12], *packet=frame->packet;`
409
410			`frame->length = (uint16)length;`
411
412			`//Calculate checksums`
413			`if(packet[ETHERNET_FRAME_TYPE+1] == 0x00) //IP`
414			`{`
415			`length2 = length - IP_VERSION_LENGTH;`
416			`packet[IP_LENGTH] = (uint8)(length2 >> 8);`
417			`packet[IP_LENGTH+1] = (uint8)length2;`
418			`memset(packet+IP_CHECKSUM, 0, 2);`
419			`checksum = IPChecksum(0xffff, packet+IP_VERSION_LENGTH, 20);`
420			`packet[IP_CHECKSUM] = (unsigned char)(checksum >> 8);`
421			`packet[IP_CHECKSUM+1] = (unsigned char)checksum;`
422			`if(packet[IP_PROTOCOL] == 0x01) //PING`
423			`{`
424			`memset(packet+PING_CHECKSUM, 0, 2);`
425			`checksum = IPChecksum(0xffff, packet+PING_TYPE, length-PING_TYPE);`
426			`packet[PING_CHECKSUM] = (unsigned char)(checksum >> 8);`
427			`packet[PING_CHECKSUM+1] = (unsigned char)checksum;`
428			`}`
429			`else if(packet[IP_PROTOCOL] == 0x11) //UDP`
430			`{`
431			`length2 = length - UDP_SOURCE_PORT;`
432			`packet[UDP_LENGTH] = (uint8)(length2 >> 8);`
433			`packet[UDP_LENGTH+1] = (uint8)length2;`
434			`memcpy(pseudo+PSEUDO_IP_SOURCE, packet+IP_SOURCE, 4);`
435			`memcpy(pseudo+PSEUDO_IP_DEST, packet+IP_DEST, 4);`
436			`pseudo[PSEUDO_ZERO] = 0;`
437			`pseudo[PSEUDO_IP_PROTOCOL] = packet[IP_PROTOCOL];`
438			`memcpy(pseudo+PSEUDO_LENGTH, packet+UDP_LENGTH, 2);`
439			`checksum = IPChecksum(0xffff, pseudo, 12);`
440			`memset(packet+UDP_CHECKSUM, 0, 2);`
441			`length2 = (packet[UDP_LENGTH] << 8) + packet[UDP_LENGTH+1];`
442			`checksum = IPChecksum(checksum, packet+UDP_SOURCE_PORT, length2);`
443			`packet[UDP_CHECKSUM] = (unsigned char)(checksum >> 8);`
444			`packet[UDP_CHECKSUM+1] = (unsigned char)checksum;`
445			`}`
446			`else if(packet[IP_PROTOCOL] == 0x06) //TCP`
447			`{`
448			`memcpy(pseudo+PSEUDO_IP_SOURCE, packet+IP_SOURCE, 4);`
449			`memcpy(pseudo+PSEUDO_IP_DEST, packet+IP_DEST, 4);`
450			`pseudo[PSEUDO_ZERO] = 0;`
451			`pseudo[PSEUDO_IP_PROTOCOL] = packet[IP_PROTOCOL];`
452			`length2 = (packet[IP_LENGTH] << 8) + packet[IP_LENGTH+1];`
453			`length2 = length2 - 20;`
454			`pseudo[PSEUDO_LENGTH] = (unsigned char)(length2 >> 8);`
455			`pseudo[PSEUDO_LENGTH+1] = (unsigned char)length2;`
456			`checksum = IPChecksum(0xffff, pseudo, 12);`
457			`memset(packet+TCP_CHECKSUM, 0, 2);`
458			`checksum = IPChecksum(checksum, packet+TCP_SOURCE_PORT, length2);`
459			`packet[TCP_CHECKSUM] = (unsigned char)(checksum >> 8);`
460			`packet[TCP_CHECKSUM+1] = (unsigned char)checksum;`
461			`}`
462			`}`
463
464	160	rhoads	`length2 = length - TCP_DATA;`
465			`if(socket && (packet[TCP_FLAGS] & (TCP_FLAGS_FIN \| TCP_FLAGS_SYN)))`
466	155	rhoads	`length2 = 1;`
467			`frame->socket = socket;`
468			`frame->timeout = 0;`
469			`frame->retryCnt = 0;`
470			`if(socket)`
471			`frame->seqEnd = socket->seq + length2;`
472			`IPSendFrame(frame);`
473			`}`
474
475
476			`static void TCPSendPacket(IPSocket socket, IPFrame frame, int length)`
477			`{`
478			`uint8 *packet = frame->packet;`
479	160	rhoads	`int flags, count;`
480	155	rhoads
481			`flags = packet[TCP_FLAGS];`
482			`memcpy(packet, socket->headerSend, TCP_SEQ);`
483	209	rhoads	`packet[TCP_FLAGS] = (uint8)flags \| (socket->headerSend[TCP_FLAGS] & TCP_FLAGS_PSH);`
484	155	rhoads	`if(flags & TCP_FLAGS_SYN)`
485			`packet[TCP_HEADER_LENGTH] = 0x60; //set maximum segment size`
486			`else`
487			`packet[TCP_HEADER_LENGTH] = 0x50;`
488			`packet[TCP_SEQ] = (uint8)(socket->seq >> 24);`
489			`packet[TCP_SEQ+1] = (uint8)(socket->seq >> 16);`
490			`packet[TCP_SEQ+2] = (uint8)(socket->seq >> 8);`
491			`packet[TCP_SEQ+3] = (uint8)socket->seq;`
492			`packet[TCP_ACK] = (uint8)(socket->ack >> 24);`
493			`packet[TCP_ACK+1] = (uint8)(socket->ack >> 16);`
494			`packet[TCP_ACK+2] = (uint8)(socket->ack >> 8);`
495			`packet[TCP_ACK+3] = (uint8)socket->ack;`
496	160	rhoads	`count = FrameFreeCount - FRAME_COUNT_WINDOW;`
497			`if(count < 1)`
498			`count = 1;`
499	165	rhoads	`if(count > 4)`
500			`count = 4;`

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