📄 tcp.lst
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460 3 // After sending the SYN ACK the client browser will
461 3 // blast me with 2 messages, an ACK, and a HTTP GET
462 3 tcp_send(FLG_SYN | FLG_ACK, 28, nr);
463 3
464 3 // My SYN flag increments my sequence number
465 3 // My sequence number is always updated to point to
466 3 // the next byte to be sent. So the incoming ack
467 3 // number should equal my sequence number
468 3 conxn[nr].my_sequence++;
469 3
470 3 conxn[nr].state = STATE_SYN_RCVD;
471 3 if (debug) printf("TCP: Entered SYN RCVD state\n");
472 3 }
473 2 else
474 2 {
475 3 // Sender is out of sync so send reset
476 3 conxn[nr].ipaddr = 0;
477 3 tcp_send(FLG_RST, 20, NO_CONNECTION);
478 3 }
479 2 break;
480 2
481 2
482 2 case STATE_SYN_RCVD:
483 2 // He may already be sending me data - should process it
484 2 conxn[nr].his_sequence += data_len;
485 2 conxn[nr].his_ack = tcp->ack_number;
486 2
487 2 if (tcp->flags & FLG_FIN)
488 2 {
489 3 // His FIN counts as a byte of data
C51 COMPILER V7.06 TCP 05/19/2004 15:18:11 PAGE 9
490 3 conxn[nr].his_sequence++;
491 3 tcp_send(FLG_ACK, 20, nr);
492 3 conxn[nr].state = STATE_CLOSE_WAIT;
493 3 if (debug) printf("TCP: Entered CLOSE_WAIT state\n");
494 3
495 3 // At this point we would normally wait for the application
496 3 // to close. For now, send FIN right away.
497 3 tcp_send(FLG_FIN | FLG_ACK, 20, nr);
498 3 conxn[nr].my_sequence++; // For my FIN
499 3 conxn[nr].state = STATE_LAST_ACK;
500 3 if (debug) printf("TCP: Entered LAST ACK state\n");
501 3 }
502 2
503 2 // Make sure he is ACKing my SYN
504 2 else if (tcp->ack_number == conxn[nr].my_sequence)
505 2 {
506 3 conxn[nr].state = STATE_ESTABLISHED;
507 3 if (debug) printf("TCP: Entered ESTABLISHED state\n");
508 3 // If sender sent data ignore it and he will resend
509 3 // Do not send response because we received no
510 3 // data... wait for client to send something to me
511 3 }
512 2 break;
513 2
514 2
515 2 case STATE_ESTABLISHED:
516 2 conxn[nr].his_ack = tcp->ack_number;
517 2
518 2 if (tcp->flags & FLG_FIN)
519 2 {
520 3 // His FIN counts as a byte of data
521 3 conxn[nr].his_sequence++;
522 3 tcp_send(FLG_ACK, 20, nr);
523 3 conxn[nr].state = STATE_CLOSE_WAIT;
524 3 if (debug) printf("TCP: Entered CLOSE_WAIT state\n");
525 3
526 3 // At this point we would normally wait for the application
527 3 // to close. For now, send FIN immediately.
528 3 tcp_send(FLG_FIN | FLG_ACK, 20, nr);
529 3 conxn[nr].my_sequence++; // For my FIN
530 3 conxn[nr].state = STATE_LAST_ACK;
531 3 if (debug) printf("TCP: Entered LAST ACK state\n");
532 3 }
533 2 else if (data_len != 0)
534 2 {
535 3 // Received normal TCP segment from sender with data
536 3 // Send an ACK immediately and pass the data on to
537 3 // the application
538 3 conxn[nr].his_sequence += data_len;
539 3 tcp_send(FLG_ACK, 20, nr); // Send ACK
540 3
541 3
542 3 // Send pointer to start of TCP payload
543 3 // http_server increments my sequence number when
544 3 // sending so don't worry about it here
545 3 result = http_server(inbuf, header_len, nr, 0);
546 3
547 3 // Start timer to close conxn if no activity
548 3 conxn[nr].inactivity = INACTIVITY_TIME;
549 3 }
550 2 break;
551 2
C51 COMPILER V7.06 TCP 05/19/2004 15:18:11 PAGE 10
552 2
553 2 case STATE_CLOSE_WAIT:
554 2 // With this code, should not get here
555 2 if (debug) printf("TCP: Oops! Rcvd unexpected message\n");
556 2
557 2 break;
558 2
559 2
560 2 case STATE_LAST_ACK:
561 2 conxn[nr].his_ack = tcp->ack_number;
562 2
563 2 // If he ACK's my FIN then close
564 2 if (tcp->ack_number == conxn[nr].my_sequence)
565 2 {
566 3 conxn[nr].state = STATE_CLOSED;
567 3 conxn[nr].ipaddr = 0; // Free up struct area
568 3 just_closed = TRUE;
569 3 }
570 2 break;
571 2
572 2
573 2 case STATE_FIN_WAIT_1:
574 2 // He may still be sending me data - should process it
575 2 conxn[nr].his_sequence += data_len;
576 2 conxn[nr].his_ack = tcp->ack_number;
577 2
578 2 if (tcp->flags & FLG_FIN)
579 2 {
580 3 // His FIN counts as a byte of data
581 3 conxn[nr].his_sequence++;
582 3 tcp_send(FLG_ACK, 20, nr);
583 3
584 3 // If he has ACK'd my FIN then we can close connection
585 3 if (tcp->ack_number == conxn[nr].my_sequence)
586 3 {
587 4 conxn[nr].state = STATE_TIME_WAIT;
588 4 if (debug) printf("TCP: Entered TIME_WAIT state\n");
589 4
590 4 conxn[nr].state = STATE_CLOSED;
591 4 conxn[nr].ipaddr = 0; // Free up connection
592 4 just_closed = TRUE;
593 4 }
594 3 else
595 3 {
596 4 // He has not ACK'd my FIN. This happens when there is a simultaneous
597 4 // close - I got his FIN but he has not yet ACK'd my FIN
598 4 conxn[nr].state = STATE_CLOSING;
599 4 if (debug) printf("TCP: Entered CLOSING state\n");
600 4 }
601 3 }
602 2 else if (tcp->ack_number == conxn[nr].my_sequence)
603 2 {
604 3 // He has ACK'd my FIN but has not sent a FIN yet himself
605 3 conxn[nr].state = STATE_FIN_WAIT_2;
606 3 if (debug) printf("TCP: Entered FIN_WAIT_2 state\n");
607 3 }
608 2 break;
609 2
610 2
611 2 case STATE_FIN_WAIT_2:
612 2 // He may still be sending me data - should process it
613 2 conxn[nr].his_sequence += data_len;
C51 COMPILER V7.06 TCP 05/19/2004 15:18:11 PAGE 11
614 2 conxn[nr].his_ack = tcp->ack_number;
615 2
616 2 if (tcp->flags & FLG_FIN)
617 2 {
618 3 conxn[nr].his_sequence++; // For his FIN flag
619 3 tcp_send(FLG_ACK, 20, nr);
620 3 conxn[nr].state = STATE_TIME_WAIT;
621 3 if (debug) printf("TCP: Entered TIME_WAIT state\n");
622 3 conxn[nr].state = STATE_CLOSED;
623 3 conxn[nr].ipaddr = 0; // Free up struct area
624 3 just_closed = TRUE;
625 3 }
626 2 break;
627 2
628 2
629 2 case STATE_TIME_WAIT:
630 2 // With this code, should not get here
631 2 if (debug) printf("TCP: Oops! In TIME_WAIT state\n");
632 2 break;
633 2
634 2
635 2 case STATE_CLOSING:
636 2 // Simultaneous close has happened. I have received his FIN
637 2 // but he has not yet ACK'd my FIN. Waiting for ACK.
638 2 // Will not receive data in this state
639 2 conxn[nr].his_ack = tcp->ack_number;
640 2
641 2 if (tcp->ack_number == conxn[nr].my_sequence)
642 2 {
643 3 conxn[nr].state = STATE_TIME_WAIT;
644 3 if (debug) printf("TCP: Entered TIME_WAIT state\n");
645 3
646 3 // Do not send any response to his ACK
647 3 conxn[nr].state = STATE_CLOSED;
648 3 conxn[nr].ipaddr = 0; // Free up struct area
649 3 just_closed = TRUE;
650 3 }
651 2 break;
652 2
653 2
654 2 default:
655 2 if (debug) printf("TCP: Error, no handler\n");
656 2 break;
657 2 }
658 1
659 1 // This is for debug, to see when conxn closes
660 1 if (just_closed)
661 1 {
662 2 just_closed = FALSE;
663 2 if (debug)
664 2 {
665 3 printf("TCP: Closed connection ");
666 3 memset(text, 0, 10);
667 3 itoa((UINT)nr, text, 10);
668 3 printf(text);
669 3 printf("\n");
670 3 }
671 2 }
672 1 }
673
674
675
C51 COMPILER V7.06 TCP 05/19/2004 15:18:11 PAGE 12
MODULE INFORMATION: STATIC OVERLAYABLE
CODE SIZE = 4739 ----
CONSTANT SIZE = 839 ----
XDATA SIZE = 231 19
PDATA SIZE = ---- ----
DATA SIZE = ---- ----
IDATA SIZE = 6 25
BIT SIZE = ---- ----
END OF MODULE INFORMATION.
C51 COMPILATION COMPLETE. 0 WARNING(S), 0 ERROR(S)
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