1               		.file	"tcp.c"
   2               	__SREG__ = 0x3f
   3               	__SP_H__ = 0x3e
   4               	__SP_L__ = 0x3d
   5               	__CCP__  = 0x34
   6               	__tmp_reg__ = 0
   7               	__zero_reg__ = 1
   8               		.global __do_copy_data
   9               		.global __do_clear_bss
  11               		.text
  12               	.Ltext0:
 120               	.global	tcp_send_packet
 122               	tcp_send_packet:
   1:net/tcp.c     **** /*
   2:net/tcp.c     **** ,-----------------------------------------------------------------------------------------.
   3:net/tcp.c     **** | net/tcp
   4:net/tcp.c     **** |-----------------------------------------------------------------------------------------
   5:net/tcp.c     **** | this file implements a very basic tcp protocol
   6:net/tcp.c     **** | - very basic
   7:net/tcp.c     **** |
   8:net/tcp.c     **** | KNOWN PROBLEMS:
   9:net/tcp.c     **** | - it does not yet check the tcp checksum of incoming packets!!
  10:net/tcp.c     **** | - something with the seq/ack calc might be buggy
  11:net/tcp.c     **** |   -> must be checked by sending bad tcp packets/re-request etc [[TODO!]]
  12:net/tcp.c     **** |
  13:net/tcp.c     **** | Author   : {{removed according to contest rules}}
  14:net/tcp.c     **** |            -> circuitcellar.com avr design contest 2006
  15:net/tcp.c     **** |            -> Entry #AT2616
  16:net/tcp.c     **** |
  17:net/tcp.c     **** |-----------------------------------------------------------------------------------------
  18:net/tcp.c     **** | License:
  19:net/tcp.c     **** | This program is free software; you can redistribute it and/or modify it under
  20:net/tcp.c     **** | the terms of the GNU General Public License as published by the Free Software
  21:net/tcp.c     **** | Foundation; either version 2 of the License, or (at your option) any later
  22:net/tcp.c     **** | version.
  23:net/tcp.c     **** | This program is distributed in the hope that it will be useful, but
  24:net/tcp.c     **** |
  25:net/tcp.c     **** | WITHOUT ANY WARRANTY;
  26:net/tcp.c     **** |
  27:net/tcp.c     **** | without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  28:net/tcp.c     **** | PURPOSE. See the GNU General Public License for more details.
  29:net/tcp.c     **** |
  30:net/tcp.c     **** | You should have received a copy of the GNU General Public License along with
  31:net/tcp.c     **** | this program; if not, write to the Free Software Foundation, Inc., 51
  32:net/tcp.c     **** | Franklin St, Fifth Floor, Boston, MA 02110, USA
  33:net/tcp.c     **** |
  34:net/tcp.c     **** | http://www.gnu.de/gpl-ger.html
  35:net/tcp.c     **** `-----------------------------------------------------------------------------------------*/
  36:net/tcp.c     **** 
  37:net/tcp.c     **** #include "tcp.h"
  38:net/tcp.c     **** 
  39:net/tcp.c     **** //ACTIVATE DEBUG by editing this file:
  40:net/tcp.c     **** #include "debug.h"
  41:net/tcp.c     **** 
  42:net/tcp.c     **** struct tcp_socket tcp_sockets[TCP_SOCKET_COUNT];
  43:net/tcp.c     **** 
  44:net/tcp.c     **** //initialise all sockets to closed state:
  45:net/tcp.c     **** void tcp_init(){
  46:net/tcp.c     **** 	unsigned char i = 0;
  47:net/tcp.c     **** 	for(i=0; i<TCP_SOCKET_COUNT; i++){
  48:net/tcp.c     **** 		tcp_close_socket(i);
  49:net/tcp.c     **** 	}
  50:net/tcp.c     **** }
  51:net/tcp.c     **** 
  52:net/tcp.c     **** unsigned char tcp_find_free_socket(){
  53:net/tcp.c     **** 	unsigned char i;
  54:net/tcp.c     **** 	for(i=0; i<TCP_SOCKET_COUNT; i++){
  55:net/tcp.c     **** 		if (tcp_sockets[i].state == TCP_STATE_CLOSED)
  56:net/tcp.c     **** 			return i;
  57:net/tcp.c     **** 	}
  58:net/tcp.c     **** 
  59:net/tcp.c     **** 	//no free closed socket fount! -> kick an TIMED_WAIT socket
  60:net/tcp.c     **** 	for(i=0; i<TCP_SOCKET_COUNT; i++){
  61:net/tcp.c     **** 		if (tcp_sockets[i].state == TCP_STATE_TIMED_WAIT){
  62:net/tcp.c     **** 			tcp_close_socket(i);
  63:net/tcp.c     **** 			return i;
  64:net/tcp.c     **** 		}
  65:net/tcp.c     **** 	}
  66:net/tcp.c     **** 
  67:net/tcp.c     **** 	//no more free sockets ... return invalid val	
  68:net/tcp.c     **** 	return(TCP_SOCKET_COUNT);
  69:net/tcp.c     **** }
  70:net/tcp.c     **** 
  71:net/tcp.c     **** void tcp_packet_in(unsigned char *buffer, unsigned int len){
  72:net/tcp.c     **** 	unsigned char tcp_header_flags;
  73:net/tcp.c     **** 	unsigned int  source_port;
  74:net/tcp.c     **** 	unsigned int  dest_port;
  75:net/tcp.c     **** 	unsigned int  datalen;
  76:net/tcp.c     **** 	unsigned int  datapos;
  77:net/tcp.c     **** 	unsigned long source_ip;
  78:net/tcp.c     **** 	unsigned long longtmp;
  79:net/tcp.c     **** 	unsigned char socketnum;
  80:net/tcp.c     **** 	//unsigned char i;
  81:net/tcp.c     **** 
  82:net/tcp.c     **** 	//read header:
  83:net/tcp.c     **** 	//source ip:
  84:net/tcp.c     **** 	source_ip   = nic_buffer_to_ip(&buffer[IP_POS_SRC_IP]);
  85:net/tcp.c     **** 	//source port:
  86:net/tcp.c     **** 	source_port = (buffer[TCP_POS_SRC_PORT]<<8) | buffer[TCP_POS_SRC_PORT+1];
  87:net/tcp.c     **** 	//dest port
  88:net/tcp.c     **** 	dest_port   = (buffer[TCP_POS_DST_PORT]<<8) | buffer[TCP_POS_DST_PORT+1];
  89:net/tcp.c     **** 	//flags:
  90:net/tcp.c     **** 	tcp_header_flags = buffer[TCP_POS_HEADERFLAGS] & 0x3F;
  91:net/tcp.c     **** 
  92:net/tcp.c     **** 	//check if target ip matches:
  93:net/tcp.c     **** 	if (nic_buffer_to_ip(&buffer[IP_POS_DST_IP]) != nic_ip){
  94:net/tcp.c     **** 		#if TCP_DEBUG
  95:net/tcp.c     **** 		softuart_puts_progmem("TCP : ignoring packet for ip ");
  96:net/tcp.c     **** 		softuart_put_ip(nic_buffer_to_ip(&buffer[IP_POS_DST_IP]));
  97:net/tcp.c     **** 		softuart_putnewline();
  98:net/tcp.c     **** 		#endif
  99:net/tcp.c     **** 		return; //no, not for us !
 100:net/tcp.c     **** 	}
 101:net/tcp.c     **** 
 102:net/tcp.c     **** 	//do we have an open socket for this connection ?!
 103:net/tcp.c     **** 	for(socketnum=0; socketnum<TCP_SOCKET_COUNT; socketnum++){
 104:net/tcp.c     **** 		//check every not closed socket
 105:net/tcp.c     **** 		if (tcp_sockets[socketnum].state != TCP_STATE_CLOSED){
 106:net/tcp.c     **** 			//compare source port (faster check than source ip
 107:net/tcp.c     **** 			if(tcp_sockets[socketnum].source_port == source_port){
 108:net/tcp.c     **** 				//now compare the source ip:
 109:net/tcp.c     **** 				if(tcp_sockets[socketnum].source_ip == source_ip){
 110:net/tcp.c     **** 					/// yes, this is for us !
 111:net/tcp.c     **** 					//handle packet
 112:net/tcp.c     **** 					#if TCP_DEBUG
 113:net/tcp.c     **** 					softuart_puts_progmem("TCP : socket[");
 114:net/tcp.c     **** 					softuart_put_uint8(socketnum);
 115:net/tcp.c     **** 					softuart_puts_progmem("] ACK: ");
 116:net/tcp.c     **** 					softuart_put_uint16(nic_buffer_to_seq(&buffer[TCP_POS_ACK])&0xFFFF);
 117:net/tcp.c     **** 					softuart_puts_progmem(" SEQ: ");
 118:net/tcp.c     **** 					softuart_put_uint16(nic_buffer_to_seq(&buffer[TCP_POS_SEQ])&0xFFFF);
 119:net/tcp.c     **** 					softuart_puts_progmem(" -> ");
 120:net/tcp.c     **** 					#endif
 121:net/tcp.c     **** 
 122:net/tcp.c     **** 					//reset TTL:
 123:net/tcp.c     **** 					tcp_sockets[socketnum].ttl = TCP_TTL_TIMEOUT;
 124:net/tcp.c     **** 
 125:net/tcp.c     **** 					//check for connection abort (RST flag)
 126:net/tcp.c     **** 					if (tcp_header_flags & TCP_RST_FLAG){
 127:net/tcp.c     **** 						//client wants to terminate ! accept this...
 128:net/tcp.c     **** 						tcp_close_socket(socketnum);
 129:net/tcp.c     **** 						//tcp_sockets[socketnum].ack = nic_buffer_to_seq(&buffer[TCP_POS_SEQ]) + 1;
 130:net/tcp.c     **** 						//tcp_sockets[socketnum].seq = nic_buffer_to_seq(&buffer[TCP_POS_ACK]);
 131:net/tcp.c     **** 						//FIXME: what is the correct response to an RST packet ?!
 132:net/tcp.c     **** 
 133:net/tcp.c     **** 						#if TCP_DEBUG
 134:net/tcp.c     **** 						softuart_puts_progmem(" RST FLAG received -> socket CLOSED.\r\n");
 135:net/tcp.c     **** 						#endif
 136:net/tcp.c     **** 						return;
 137:net/tcp.c     **** 					}
 138:net/tcp.c     **** 
 139:net/tcp.c     **** 					switch (tcp_sockets[socketnum].state){
 140:net/tcp.c     **** 						///SNY_RECEIVED
 141:net/tcp.c     **** 						case(TCP_STATE_SYN_RECEIVED):
 142:net/tcp.c     **** 							if (tcp_header_flags == TCP_ACK_FLAG){
 143:net/tcp.c     **** 								//ok, this connection is established:
 144:net/tcp.c     **** 								//we do not need to send any data now)
 145:net/tcp.c     **** 								tcp_sockets[socketnum].state = TCP_STATE_ESTABLISHED;
 146:net/tcp.c     **** 
 147:net/tcp.c     **** 								#if TCP_DEBUG
 148:net/tcp.c     **** 								softuart_puts_progmem("ESTABLISHED");
 149:net/tcp.c     **** 								#endif
 150:net/tcp.c     **** 							}else{
 151:net/tcp.c     **** 								//invalid packet or TCP_RST_FLAG for example ...
 152:net/tcp.c     **** 								//connection reset -> close socket
 153:net/tcp.c     **** 								tcp_close_socket(socketnum);
 154:net/tcp.c     **** 								#if TCP_DEBUG
 155:net/tcp.c     **** 								softuart_puts_progmem("CLOSED");
 156:net/tcp.c     **** 								#endif
 157:net/tcp.c     **** 							}
 158:net/tcp.c     **** 							break;
 159:net/tcp.c     **** 	
 160:net/tcp.c     **** 						///ESTABLISHED
 161:net/tcp.c     **** 						case(TCP_STATE_ESTABLISHED):
 162:net/tcp.c     **** 							if (tcp_header_flags & TCP_FIN_FLAG){
 163:net/tcp.c     **** 								//connection close request
 164:net/tcp.c     **** 								//-------send ACK & goto CLOSE_WAIT---- no do this:
 165:net/tcp.c     **** 								//send ACK+FIN and goto LAST ACK:
 166:net/tcp.c     **** 								tcp_sockets[socketnum].state = TCP_STATE_LAST_ACK;
 167:net/tcp.c     **** 								tcp_sockets[socketnum].ack = nic_buffer_to_seq(&buffer[TCP_POS_SEQ]) + 1;
 168:net/tcp.c     **** 								tcp_sockets[socketnum].seq = nic_buffer_to_seq(&buffer[TCP_POS_ACK]);
 169:net/tcp.c     **** 
 170:net/tcp.c     **** 								tcp_send_packet(buffer, socketnum, (TCP_FIN_FLAG|TCP_ACK_FLAG), 0);
 171:net/tcp.c     **** 								#if TCP_DEBUG
 172:net/tcp.c     **** 								softuart_puts_progmem("LAST_ACK");
 173:net/tcp.c     **** 								#endif
 174:net/tcp.c     **** 							}else{
 175:net/tcp.c     **** 								//this is data for application!
 176:net/tcp.c     **** 								//check for error & send packet to correct application
 177:net/tcp.c     **** 
 178:net/tcp.c     **** 								///OUTGOING DATA HANDLING:
 179:net/tcp.c     **** 								//which databyte was acked ?
 180:net/tcp.c     **** 								longtmp = nic_buffer_to_seq(&buffer[TCP_POS_ACK]);
 181:net/tcp.c     **** 								//the last packet we have sent was tcp_sockets[socketnum].seq,
 182:net/tcp.c     **** 								//check it:
 183:net/tcp.c     **** 								if ((longtmp != tcp_sockets[socketnum].seq) && (longtmp != 1)){
 184:net/tcp.c     **** 									#if TCP_DEBUG
 185:net/tcp.c     **** 									softuart_puts_progmem("TCP : ack != last seqnum! retransmit : ");
 186:net/tcp.c     **** 									softuart_put_uint16(longtmp&0xFFFF);
 187:net/tcp.c     **** 									softuart_putc(' ');
 188:net/tcp.c     **** 									softuart_put_uint16(tcp_sockets[socketnum].seq&0xFFFF);
 189:net/tcp.c     **** 									softuart_putc(' ');
 190:net/tcp.c     **** 									softuart_putnewline();
 191:net/tcp.c     **** 									#endif
 192:net/tcp.c     **** 									//overwrite seq num -> send acked data !
 193:net/tcp.c     **** 									tcp_sockets[socketnum].seq = longtmp;
 194:net/tcp.c     **** 								}
 195:net/tcp.c     **** 
 196:net/tcp.c     **** 								//update our seq counter, we should send now
 197:net/tcp.c     **** 								//databyte longtmp-1 (1 = initval of seq counter)
 198:net/tcp.c     **** 								//tcp_sockets[socketnum].seq = longtmp;
 199:net/tcp.c     **** 
 200:net/tcp.c     **** 
 201:net/tcp.c     **** 								///INCOMING DATA HANDLING:
 202:net/tcp.c     **** 								//check if this is the data we expect:
 203:net/tcp.c     **** 								longtmp = nic_buffer_to_seq(&buffer[TCP_POS_SEQ]);
 204:net/tcp.c     **** 
 205:net/tcp.c     **** 								//extract data pos:
 206:net/tcp.c     **** 								datapos = (14 + ((buffer[IP_POS_VERSION] & 0x0F) << 2) + ((buffer[TCP_POS_DATA_OFFSET] & 0x
 207:net/tcp.c     **** 								datalen = ((buffer[IP_POS_PKTLEN+0]<<8) | buffer[IP_POS_PKTLEN+1])-datapos+14;
 208:net/tcp.c     **** 
 209:net/tcp.c     **** 								//we are waiting for a packet with seq = <tcp_sockets[socketnum].ack>
 210:net/tcp.c     **** 								//-> we sent an ack for packet byte n, now the seq counter of incoming
 211:net/tcp.c     **** 								//   packet has to be <n>
 212:net/tcp.c     **** 								if ((longtmp != tcp_sockets[socketnum].ack) && (tcp_sockets[socketnum].ack != 0)){
 213:net/tcp.c     **** 									//there was an error, check what to do next:
 214:net/tcp.c     **** 									if (longtmp < tcp_sockets[socketnum].ack){
 215:net/tcp.c     **** 										//we expected data x to y but we got (x-n) to y
 216:net/tcp.c     **** 										//we onlny need x to y, so discard n bytes:
 217:net/tcp.c     **** 										longtmp = (tcp_sockets[socketnum].ack - longtmp);
 218:net/tcp.c     **** 										datapos = datapos + longtmp;
 219:net/tcp.c     **** 										datalen = datalen - longtmp;
 220:net/tcp.c     **** 										#if TCP_DEBUG
 221:net/tcp.c     **** 										softuart_puts_progmem(" WARN: tcp data dup! ignoring duplicate data. ");
 222:net/tcp.c     **** 										#endif
 223:net/tcp.c     **** 									}else{ //longtmp > tcp....
 224:net/tcp.c     **** 										//uups one packet was lost during transfer !
 225:net/tcp.c     **** 										//re request this packet, send an ack for expected <seq>:
 226:net/tcp.c     **** 										#if TCP_DEBUG
 227:net/tcp.c     **** 										softuart_puts_progmem(" ERR : tcp packet lost! re-requesting. ");
 228:net/tcp.c     **** 										#endif
 229:net/tcp.c     **** 										tcp_send_packet(buffer, socketnum, (TCP_ACK_FLAG), 0);
 230:net/tcp.c     **** 										return;
 231:net/tcp.c     **** 									}
 232:net/tcp.c     **** 								}
 233:net/tcp.c     **** 
 234:net/tcp.c     **** 								//protect buffer:
 235:net/tcp.c     **** 								if (datapos > NIC_BUFFERSIZE)
 236:net/tcp.c     **** 									datapos = NIC_BUFFERSIZE;
 237:net/tcp.c     **** 								if ((datapos + datalen) > NIC_BUFFERSIZE)
 238:net/tcp.c     **** 									datalen = 0;
 239:net/tcp.c     **** 
 240:net/tcp.c     **** 								//limit datalength to length that fits into our buffer:
 241:net/tcp.c     **** 								if (datalen > (NIC_BUFFERSIZE-datapos))
 242:net/tcp.c     **** 									datalen = (NIC_BUFFERSIZE-datapos);
 243:net/tcp.c     **** 
 244:net/tcp.c     **** 								//next ack packet we will send must ack data byte n+datalen:
 245:net/tcp.c     **** 								tcp_sockets[socketnum].ack = tcp_sockets[socketnum].ack + (datalen);
 246:net/tcp.c     **** 
 247:net/tcp.c     **** 								#if TCP_DEBUG
 248:net/tcp.c     **** 								softuart_put_uint16(datalen);
 249:net/tcp.c     **** 								softuart_puts_progmem(" bytes in ");
 250:net/tcp.c     **** 								/*if (datalen>0)
 251:net/tcp.c     **** 									softuart_putnewline();
 252:net/tcp.c     **** 								for(int d=datapos; d<datapos+datalen; d++){
 253:net/tcp.c     **** 									softuart_putc(buffer[d]);
 254:net/tcp.c     **** 								}*/
 255:net/tcp.c     **** 								softuart_putnewline();
 256:net/tcp.c     **** 								#endif
 257:net/tcp.c     **** 
 258:net/tcp.c     **** 								//now call the application
 259:net/tcp.c     **** 								unsigned char appstate = TCP_APPSTATE_NONE;
 260:net/tcp.c     **** 								unsigned int  data_tx_count = 0;
 261:net/tcp.c     **** 								if ((tcp_sockets[socketnum].dest_port == IP_PORT_HTTPD)||(tcp_sockets[socketnum].dest_port 
 262:net/tcp.c     **** 									data_tx_count = httpd_data_in(buffer, datapos, datalen, socketnum, &appstate);
 263:net/tcp.c     **** 								//}else{
 264:net/tcp.c     **** 								//	data_tx_count = http_client_data_in(buffer, datapos, datalen, socketnum, &appstate);
 265:net/tcp.c     **** 								}
 266:net/tcp.c     **** 
 267:net/tcp.c     **** 								//application modified appstate
 268:net/tcp.c     **** 								switch(appstate){
 269:net/tcp.c     **** 									case (TCP_APPSTATE_EMPTYACK):
 270:net/tcp.c     **** 										tcp_send_packet(buffer, socketnum, (TCP_ACK_FLAG), 0);
 271:net/tcp.c     **** 										tcp_sockets[socketnum].seq = tcp_sockets[socketnum].seq;
 272:net/tcp.c     **** 
 273:net/tcp.c     **** 										break;
 274:net/tcp.c     **** 									case (TCP_APPSTATE_HAS_TXDATA):
 275:net/tcp.c     **** 										//send data
 276:net/tcp.c     **** 										tcp_send_packet(buffer, socketnum, (TCP_ACK_FLAG), data_tx_count);
 277:net/tcp.c     **** 										//seq counter update:
 278:net/tcp.c     **** 										tcp_sockets[socketnum].seq = tcp_sockets[socketnum].seq + data_tx_count;
 279:net/tcp.c     **** 										#if TCP_DEBUG
 280:net/tcp.c     **** 										softuart_puts_progmem("TCP : last byte sent = ");
 281:net/tcp.c     **** 										softuart_put_uint16(tcp_sockets[socketnum].seq&0xFFFF);