WebSVN – Kolibri OS – Blame – /kernel/branches/net/network/tcp.inc

Rev	Author	Line No.	Line
1196	hidnplayr	1	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		2	;; ;;
1514	hidnplayr	3	;; Copyright (C) KolibriOS team 2004-2010. All rights reserved. ;;
1196	hidnplayr	4	;; Distributed under terms of the GNU General Public License ;;
		5	;; ;;
		6	;; TCP.INC ;;
		7	;; ;;
		8	;; Part of the tcp/ip network stack for KolibriOS ;;
		9	;; ;;
1514	hidnplayr	10	;; Written by hidnplayr@kolibrios.org ;;
1196	hidnplayr	11	;; ;;
1514	hidnplayr	12	;; Based on the code of 4.4BSD ;;
		13	;; ;;
1196	hidnplayr	14	;; GNU GENERAL PUBLIC LICENSE ;;
		15	;; Version 2, June 1991 ;;
		16	;; ;;
		17	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
1159	hidnplayr	18
1206	hidnplayr	19	$Revision: 1514 $
1159	hidnplayr	20
1514	hidnplayr	21	; Socket states
		22	TCB_CLOSED equ 0
		23	TCB_LISTEN equ 1
		24	TCB_SYN_SENT equ 2
		25	TCB_SYN_RECEIVED equ 3
		26	TCB_ESTABLISHED equ 4
		27	TCB_CLOSE_WAIT equ 5
		28	TCB_FIN_WAIT_1 equ 6
		29	TCB_CLOSING equ 7
		30	TCB_LAST_ACK equ 8
		31	TCB_FIN_WAIT_2 equ 9
		32	TCB_TIMED_WAIT equ 10
1196	hidnplayr	33
1514	hidnplayr	34	; Socket Flags
		35	TF_ACKNOW equ 1 shl 0 ; ack peer immediately
		36	TF_DELACK equ 1 shl 1 ; ack, but try to delay it
		37	TF_NODELAY equ 1 shl 2 ; don't delay packets to coalesce
		38	TF_NOOPT equ 1 shl 3 ; don't use tcp options
		39	TF_SENTFIN equ 1 shl 4 ; have sent FIN
		40	TF_REQ_SCALE equ 1 shl 5 ; have/will request window scaling
		41	TF_RCVD_SCALE equ 1 shl 6 ; other side has requested scaling
		42	TF_REQ_TSTMP equ 1 shl 7 ; have/will request timestamps
		43	TF_RCVD_TSTMP equ 1 shl 8 ; a timestamp was received in SYN
		44	TF_SACK_PERMIT equ 1 shl 9 ; other side said I could SACK
1249	hidnplayr	45
1514	hidnplayr	46	; Segment flags
		47	TH_FIN equ 1 shl 0
		48	TH_SYN equ 1 shl 1
		49	TH_RST equ 1 shl 2
		50	TH_PUSH equ 1 shl 3
		51	TH_ACK equ 1 shl 4
		52	TH_URG equ 1 shl 5
1318	hidnplayr	53
1514	hidnplayr	54	; Segment header options
		55	TCP_OPT_EOL equ 0 ; End of option list.
		56	TCP_OPT_NOP equ 1 ; No-Operation.
		57	TCP_OPT_MAXSEG equ 2 ; Maximum Segment Size.
		58	TCP_OPT_WINDOW equ 3 ; window scale
		59	TCP_OPT_TIMESTAMP equ 8
		60
		61	struct TCP_segment
1159	hidnplayr	62	.SourcePort dw ?
		63	.DestinationPort dw ?
		64	.SequenceNumber dd ?
		65	.AckNumber dd ?
1196	hidnplayr	66	.DataOffset db ? ; DataOffset[0-3 bits] and Reserved[4-7]
		67	.Flags db ? ; Reserved[0-1 bits]\|URG\|ACK\|PSH\|RST\|SYN\|FIN
1159	hidnplayr	68	.Window dw ?
		69	.Checksum dw ?
		70	.UrgentPointer dw ?
1514	hidnplayr	71	.Data: ; ..or options
1159	hidnplayr	72	ends
		73
1274	hidnplayr	74	struct tcp_in_queue_entry
		75	.data_ptr dd ?
		76	.data_size dd ?
1514	hidnplayr	77	.offset dd ?
1274	hidnplayr	78	.size:
		79	ends
		80
		81	struct tcp_out_queue_entry
		82	.data_ptr dd ?
		83	.data_size dd ?
1514	hidnplayr	84
1274	hidnplayr	85	.size:
		86	ends
		87
1196	hidnplayr	88	align 4
		89	uglobal
1514	hidnplayr	90	TCP_segments_tx rd IP_MAX_INTERFACES
		91	TCP_segments_rx rd IP_MAX_INTERFACES
		92	TCP_bytes_rx rq IP_MAX_INTERFACES
		93	TCP_bytes_tx rq IP_MAX_INTERFACES
		94	TCP_sequence_num dd ?
1196	hidnplayr	95	endg
		96
		97
		98	;-----------------------------------------------------------------
		99	;
		100	; TCP_init
		101	;
		102	; This function resets all TCP variables
		103	;
		104	; IN: /
		105	; OUT: /
		106	;
		107	;-----------------------------------------------------------------
		108	align 4
		109	TCP_init:
		110
		111	xor eax, eax
1514	hidnplayr	112	mov edi, TCP_segments_tx
		113	mov ecx, (6*IP_MAX_INTERFACES)
1196	hidnplayr	114	rep stosd
		115
1514	hidnplayr	116	mov [TCP_sequence_num],1
1196	hidnplayr	117
		118	ret
		119
		120
		121	;-----------------------------------------------------------------
		122	;
1514	hidnplayr	123	; decrease socket ttls
1159	hidnplayr	124	;
1514	hidnplayr	125	; IN: /
		126	; OUT: /
1159	hidnplayr	127	;
1514	hidnplayr	128	; destroys: eax
		129	;
1196	hidnplayr	130	;-----------------------------------------------------------------
		131	align 4
1514	hidnplayr	132	TCP_timer_1000ms:
		133	; scan through all the active TCP sockets, decrementing active timers
1159	hidnplayr	134
1514	hidnplayr	135	mov eax, net_sockets
		136	.loop:
		137	mov eax, [eax + SOCKET.NextPtr]
		138	.check_only:
		139	or eax, eax
1159	hidnplayr	140	jz .exit
		141
1514	hidnplayr	142	cmp [eax + SOCKET.Type], IP_PROTO_TCP
		143	jne .loop
1249	hidnplayr	144
1514	hidnplayr	145	cmp [eax + TCP_SOCKET.t_timer], 0
1159	hidnplayr	146	jne .decrement_tcb
1514	hidnplayr	147	;;;;;; cmp [eax + TCP_SOCKET.wndsizeTimer], 0
1159	hidnplayr	148	jne .decrement_wnd
1514	hidnplayr	149	jmp .loop
1159	hidnplayr	150
		151	.decrement_tcb:
1274	hidnplayr	152	; decrement it, delete socket if TCB timer = 0 & socket in timewait state
1514	hidnplayr	153	dec [eax + TCP_SOCKET.t_timer]
		154	jnz .loop
1159	hidnplayr	155
1514	hidnplayr	156	cmp [eax + TCP_SOCKET.t_state], TCB_TIMED_WAIT
		157	jne .loop
1159	hidnplayr	158
1514	hidnplayr	159	push [eax + SOCKET.NextPtr]
		160	call SOCKET_free
		161	pop eax
		162	jmp .check_only
1159	hidnplayr	163
		164	.decrement_wnd:
1514	hidnplayr	165	;;;;;; dec [eax + TCP_SOCKET.wndsizeTimer]
1159	hidnplayr	166
		167	.exit:
		168	ret
		169
		170
1249	hidnplayr	171
1514	hidnplayr	172	;----------------------
1159	hidnplayr	173	;
1514	hidnplayr	174	; TCP_500ms
1159	hidnplayr	175	;
1514	hidnplayr	176	;----------------------
1196	hidnplayr	177	align 4
1514	hidnplayr	178	TCP_500ms:
1159	hidnplayr	179
1514	hidnplayr	180	add [TCP_sequence_num], 64000
1159	hidnplayr	181
1249	hidnplayr	182	ret
1159	hidnplayr	183
		184
		185
1514	hidnplayr	186	;----------------------
		187	;
		188	; TCP_10ms
		189	;
		190	;----------------------
		191	align 4
		192	TCP_10ms:
1254	hidnplayr	193
1514	hidnplayr	194	; todo: decrease timers
1159	hidnplayr	195
1514	hidnplayr	196	ret
1159	hidnplayr	197
		198
		199
1318	hidnplayr	200
1249	hidnplayr	201	;-----------------------------------------------------------------
		202	;
1514	hidnplayr	203	; TCP_input:
1159	hidnplayr	204	;
1514	hidnplayr	205	; IN: [esp] = ptr to buffer
		206	; [esp+4] = buffer size
		207	; ebx = ptr to device struct
		208	; ecx = segment size
		209	; edx = ptr to TCP segment
1196	hidnplayr	210	;
1514	hidnplayr	211	; esi = ipv4 source address
		212	; edi = ipv4 dest address
		213	;
1196	hidnplayr	214	; OUT: /
		215	;
		216	;-----------------------------------------------------------------
1249	hidnplayr	217	align 4
1514	hidnplayr	218	TCP_input:
1159	hidnplayr	219
1514	hidnplayr	220	DEBUGF 1,"TCP_input\n"
1196	hidnplayr	221
1514	hidnplayr	222	; Offset must be greater than or equal to the size of the standard TCP header (20) and less than or equal to the TCP length.
1254	hidnplayr	223
1514	hidnplayr	224	movzx eax, [edx + TCP_segment.DataOffset]
		225	and eax, 0xf0
		226	shr al , 2
		227
		228	DEBUGF 1,"data offset: %u\n", eax
		229
		230	cmp eax, 20
		231	jl .drop
		232
		233	cmp eax, ecx
		234	jg .drop
		235
		236	;-------------------------------
		237	; Now, re-calculate the checksum
		238
		239	push eax edx ebx
		240
		241	push edi
		242	push esi
		243	mov esi, edx
		244	call TCP_checksum ; this destroys edx, ecx and esi (but not edi! :)
		245
		246	pop ebx edx eax
		247
		248	cmp [edx + TCP_segment.Checksum], 0
		249	jnz .drop
		250
		251	DEBUGF 1,"Checksum is correct\n"
		252
		253	;-----------------------------------------------------------------------------------------
		254	; Check if this packet has a timestamp option (We do it here so we can process it quickly)
		255
		256	cmp eax, 20 + 12 ; Timestamp option is 12 bytes
		257	jl .no_timestamp
		258	je .is_ok
		259
		260	cmp byte [edx + TCP_segment.Data + 12], 0 ; end of option list
		261	jne .no_timestamp
		262
		263	.is_ok:
		264	test [edx + TCP_segment.Flags], TH_SYN ; SYN flag must not be set
		265	jnz .no_timestamp
		266
		267	cmp dword [edx + TCP_segment.Data], 0x0101080a ; Timestamp header
		268	jne .no_timestamp
		269
		270	DEBUGF 1,"timestamp ok\n"
		271
		272	; TODO: Parse the options
		273	; TODO: Set a Bit in the TCP to tell all options are parsed
		274
		275	ret
		276
		277	.no_timestamp:
		278
		279	;-------------------------------------------
		280	; Convert Big-endian values to little endian
		281
		282	ntohld [edx + TCP_segment.SequenceNumber]
		283	ntohld [edx + TCP_segment.AckNumber]
		284
		285	ntohlw [edx + TCP_segment.Window]
		286	ntohlw [edx + TCP_segment.UrgentPointer]
		287
		288	;------------------------------------------------------------
		289	; Next thing to do is find the TCB (thus, the socket pointer)
		290
1274	hidnplayr	291	; IP Packet TCP Destination Port = local Port
1514	hidnplayr	292	; (IP Packet SenderAddress = Remote IP) OR (Remote IP = 0)
1318	hidnplayr	293	; (IP Packet TCP Source Port = remote Port) OR (remote Port = 0)
1159	hidnplayr	294
		295	mov ebx, net_sockets
		296
1249	hidnplayr	297	.socket_loop:
1514	hidnplayr	298	mov ebx, [ebx + SOCKET.NextPtr]
1159	hidnplayr	299	or ebx, ebx
1514	hidnplayr	300	jz .drop_with_reset
1159	hidnplayr	301
1514	hidnplayr	302	cmp [ebx + SOCKET.Type], IP_PROTO_TCP
1249	hidnplayr	303	jne .socket_loop
1159	hidnplayr	304
1514	hidnplayr	305	mov ax, [edx + TCP_segment.DestinationPort]
		306	cmp [ebx + TCP_SOCKET.LocalPort], ax
		307	jne .socket_loop
		308
		309	mov eax, [ebx + IP_SOCKET.RemoteIP]
1249	hidnplayr	310	cmp eax, esi
		311	je @f
		312	test eax, eax
1514	hidnplayr	313	jnz .socket_loop
1249	hidnplayr	314	@@:
1159	hidnplayr	315
1514	hidnplayr	316	mov ax, [ebx + TCP_SOCKET.RemotePort]
		317	cmp [edx + TCP_segment.SourcePort] , ax
1274	hidnplayr	318	je .found_socket
1249	hidnplayr	319	test ax, ax
1254	hidnplayr	320	jnz .socket_loop
1274	hidnplayr	321	.found_socket:
1514	hidnplayr	322	DEBUGF 1,"Socket ptr: %x\n", ebx
1254	hidnplayr	323
1514	hidnplayr	324	; ebx now contains the pointer to the socket
1257	hidnplayr	325
1514	hidnplayr	326	;----------------------------
		327	; Check if socket isnt closed
		328
		329	cmp [TCP_SOCKET.t_state], TCB_CLOSED
		330	je .drop
		331
		332	;----------------
		333	; Lock the socket
		334
		335	add ebx, SOCKET.lock ; TODO: figure out if we should lock now already
1249	hidnplayr	336	call wait_mutex
1514	hidnplayr	337	sub ebx, SOCKET.lock
1159	hidnplayr	338
1514	hidnplayr	339	;---------------------------------------
		340	; unscale the window into a 32 bit value ;;;;;;
1159	hidnplayr	341
1514	hidnplayr	342	movzx eax, [edx + TCP_segment.Window]
		343	xchg al, ah
		344
		345	test [edx + TCP_segment.Flags], TH_SYN
		346	jnz .no_syn
		347
		348	mov cl , [ebx + TCP_SOCKET.SND_SCALE]
		349	shl eax, cl
		350
		351	.no_syn:
		352
		353	;-----------------------------------
		354	; Is this socket a listening socket?
		355
		356	; If so, create a new socket
		357
		358	test [ebx + SOCKET.options], SO_ACCEPTCON
		359	jz .no_accept_conn
		360
		361
		362	; TODO: create a new socket
		363
		364
		365	.no_accept_conn:
		366
		367	;----------------------------
		368	; Compute window scale factor
		369
		370
		371	; TODO
		372
		373
		374	;-------------------------------------
		375	; Reset idle timer and keepalive timer
		376
		377
		378	; TODO
		379
		380	;-----------------------------------------
		381	; Process TCP options if not in LISTEN state
		382
		383	test [ebx + TCP_SOCKET.t_state], TCB_LISTEN
		384	jz .dont_do_options
		385
		386	call TCP_do_options
		387
		388	.dont_do_options:
		389
		390	;-----------------------------------------------------------------------
		391	; Time to do some header prediction (Original Principle by Van Jacobson)
		392
		393
		394	; There are two common cases for an uni-directional data transfer.
		395	;
		396	; General rule: the packets has no control flags, is in-sequence,
		397	; window width didnt change and we're not retransmitting.
		398	;
		399	; Second rules:
		400	; - If the length is 0 and the ACK moved forward, we're the sender side of the transfer.
		401	; In this case we'll free the ACK'ed data and notify higher levels that we have free space in buffer
		402	;
		403	; - If the length is not 0 and the ACK didn't move, we're the receiver side of the transfer.
		404	; If the packets are in order (data queue is empty), add the data to the socket buffer and request a delayed ACK
		405
		406	cmp [TCP_SOCKET.t_state], TCB_ESTABLISHED
		407	jnz .not_uni_xfer
		408
		409	test [TCP_segment.Flags], TH_SYN + TH_FIN + TH_RST + TH_URG
		410	jnz .not_uni_xfer
		411
		412	test [TCP_segment.Flags], TH_ACK
		413	jz .not_uni_xfer
		414
		415	mov eax, [edx + TCP_segment.SequenceNumber]
		416	cmp eax, [ebx + TCP_SOCKET.RCV_NXT]
		417	jne .not_uni_xfer
		418
		419	movzx eax, [edx + TCP_segment.Window] ;;;;;
		420	cmp eax, [ebx + TCP_SOCKET.SND_WND]
		421	jne .not_uni_xfer
		422
		423	mov eax, [ebx + TCP_SOCKET.SND_NXT]
		424	cmp eax, [ebx + TCP_SOCKET.SND_MAX]
		425	jne .not_uni_xfer
		426
		427	;-------------------------------------------------------------------------------
		428	; If last ACK falls within this segment's sequence number, record the timestamp.
		429
		430	; TODO: check if it has a timestamp
		431
		432
		433
		434
		435	;---------------------------------------
		436	; check if we are sender in the uni-xfer
		437
		438	; If the following 4 conditions are all true, this segment is a pure ACK.
		439	;
		440	; - The segment contains no data (ti_len is 0).
		441
		442	movzx eax, [edx + TCP_segment.DataOffset]
1274	hidnplayr	443	and eax, 11110000b
		444	shr eax, 2
		445	sub ecx, eax
1514	hidnplayr	446	jnz .not_sender
1274	hidnplayr	447
1514	hidnplayr	448	; - The acknowledgment field in the segment (ti_ack) is greater than the largest unacknowledged sequence number (snd_una).
		449	; Since this test is "greater than" and not "greater than or equal to," it is true only if some positive amount of data is acknowledged by the ACK.
1274	hidnplayr	450
1514	hidnplayr	451	mov eax, [edx + TCP_segment.AckNumber]
		452	cmp eax, [ebx + TCP_SOCKET.SND_UNA]
		453	jle .not_uni_xfer
1159	hidnplayr	454
1514	hidnplayr	455	; - The acknowledgment field in the segment (ti_ack) is less than or equal to the maximum sequence number sent (snd_max).
1159	hidnplayr	456
1514	hidnplayr	457	; mov eax, [edx + TCP_segment.Ack]
		458	cmp eax, [ebx + TCP_SOCKET.SND_MAX]
		459	jg .not_uni_xfer
1159	hidnplayr	460
1514	hidnplayr	461	; - The congestion window (snd_cwnd) is greater than or equal to the current send window (snd_wnd).
		462	; This test is true only if the window is fully open, that is, the connection is not in the middle of slow start or congestion avoidance.
1254	hidnplayr	463
1514	hidnplayr	464	mov eax, [ebx + TCP_SOCKET.SND_CWND]
		465	cmp eax, [ebx + TCP_SOCKET.SND_WND]
		466	jl .not_uni_xfer
1318	hidnplayr	467
1514	hidnplayr	468	DEBUGF 1,"Header prediction: we are sender\n"
1274	hidnplayr	469
1514	hidnplayr	470	;---------------------------------
		471	; Packet is a pure ACK, process it
1274	hidnplayr	472
1514	hidnplayr	473	; Update RTT estimators
1159	hidnplayr	474
1514	hidnplayr	475	; Delete acknowledged bytes from send buffer
1254	hidnplayr	476
1514	hidnplayr	477	; Stop retransmit timer
1159	hidnplayr	478
1514	hidnplayr	479	; Awaken waiting processes
1318	hidnplayr	480
1514	hidnplayr	481	; Generate more output
1254	hidnplayr	482
		483
1159	hidnplayr	484
		485
1514	hidnplayr	486	jmp .drop
1159	hidnplayr	487
1196	hidnplayr	488
		489
		490
1514	hidnplayr	491	;-------------------------------------------------
		492	; maybe we are the receiver in the uni-xfer then..
		493
		494	.not_sender:
		495	; The amount of data in the segment (ti_len) is greater than 0 (data count is in ecx)
		496
		497
		498	; The acknowledgment field (ti_ack) equals the largest unacknowledged sequence number. This means no data is acknowledged by this segment.
		499	mov eax, [edx + TCP_segment.AckNumber]
		500	cmp eax, [ebx + TCP_SOCKET.SND_UNA]
		501	jne .not_uni_xfer
		502
		503	; The reassembly list of out-of-order segments for the connection is empty (seg_next equals tp).
		504	;;;;
		505	jnz .not_uni_xfer
		506
		507	; There is room in the receive buffer for the data in the segment.
		508	;;;;
		509	jnz .not_uni_xfer
		510
		511	;-------------------------------------
		512	; Complete processing of received data
		513
		514	DEBUGF 1,"header prediction: we are receiver\nreceiving %u bytes of data\n", ecx
		515
		516	; The next expected receive sequence number (rcv_nxt) is incremented by the number of bytes of data.
		517
		518	add [ebx + TCP_SOCKET.RCV_NXT], ecx
		519
		520	; Add the data to the socket buffer
		521
		522	; The receiving process is awakened (by sorwakeup).
		523
		524	; The delayed-ACK flag is set and the input processing is complete.
		525
		526	jmp .drop
		527
		528
		529
		530
		531
		532	;----------------------------------------------------
		533	; Header prediction failed, doing it the slow way..
		534
		535	.not_uni_xfer:
		536
		537	DEBUGF 1,"Header prediction failed\n"
		538
		539	;------------------------
		540	; calculate header length ;;;;; we already calculated this before!
		541	movzx eax, [edx + TCP_segment.DataOffset]
		542	and eax, 0xf0
		543	shr eax, 2
		544
		545	; Update edx to point to data..
		546	add edx, eax
		547	; ..and ecx to give data size
		548	sub ecx, eax
		549
		550	;------------------------------
		551	; Calculate receive window size
		552
		553	;;;;
		554
		555
		556	;-------------------------
		557	; TCP slow input procedure
		558
		559	DEBUGF 1,"TCP slow input procedure\n"
		560
		561	cmp [eax + TCP_SOCKET.t_state], TCB_LISTEN
		562	je .LISTEN
		563
		564	cmp [eax + TCP_SOCKET.t_state], TCB_SYN_SENT
		565	je .SYN_SENT
		566
		567
		568	;--------------------------------------------
		569	; Protection Against Wrapped Sequence Numbers
		570
		571
		572	; First, check timestamp if present
		573
		574	;;;; TODO
		575
		576	; Then, check if at least some bytes of data are within window
		577
		578	;;;; TODO
		579
		580	jmp .trim_then_step6
		581
1249	hidnplayr	582	align 4
1514	hidnplayr	583	.LISTEN:
1196	hidnplayr	584
1514	hidnplayr	585	DEBUGF 1,"TCP state: listen\n"
1159	hidnplayr	586
1514	hidnplayr	587	test [edx + TCP_segment.Flags], TH_RST
		588	jnz .drop
1159	hidnplayr	589
1514	hidnplayr	590	test [edx + TCP_segment.Flags], TH_ACK
		591	jnz .drop_with_reset
1159	hidnplayr	592
1514	hidnplayr	593	test [edx + TCP_segment.Flags], TH_SYN
		594	jz .drop
1159	hidnplayr	595
1514	hidnplayr	596	; TODO: check if it's a broadcast or multicast, and drop if so
1159	hidnplayr	597
1514	hidnplayr	598	;;; 28.6
		599
		600	; create a new socket and fill in the nescessary variables
		601
		602	;; Exit if backlog queue is full
		603	; mov ax, [ebx + TCP_SOCKET.backlog_cur]
		604	; cmp ax, [ebx + TCP_SOCKET.backlog]
		605	; jae .exit
		606
		607	; Allocate new socket
		608	call SOCKET_alloc
		609	;;; jz .fail
		610
		611	; Copy structure from current socket to new, (including lock!)
		612	; We start at PID to reserve the socket num, and the 2 pointers at beginning of socket
		613	lea esi, [edx + SOCKET.PID]
		614	lea edi, [eax + SOCKET.PID]
		615	mov ecx, (TCP_SOCKET.end - SOCKET.PID + 3)/4
1274	hidnplayr	616	rep movsd
1159	hidnplayr	617
1514	hidnplayr	618	;; Push pointer to new socket to queue
		619	; movzx ecx, [ebx + TCP_SOCKET.backlog_cur]
		620	; inc [ebx + TCP_SOCKET.backlog_cur]
		621	; mov [ebx + TCP_SOCKET.end + ecx*4], eax
1159	hidnplayr	622
1514	hidnplayr	623	mov [eax + IP_SOCKET.RemoteIP], esi ; IP source address
1159	hidnplayr	624
1514	hidnplayr	625	mov cx, [edx + TCP_segment.SourcePort]
		626	mov [eax + TCP_SOCKET.RemotePort], cx
1159	hidnplayr	627
1514	hidnplayr	628	mov ecx, [edx + TCP_segment.SequenceNumber]
		629	mov [eax + TCP_SOCKET.IRS], ecx
1159	hidnplayr	630
1514	hidnplayr	631	mov ecx, [eax + TCP_SOCKET.ISS]
		632	mov [eax + TCP_SOCKET.SND_NXT], ecx
1159	hidnplayr	633
1514	hidnplayr	634	jmp .trim_then_step6
1159	hidnplayr	635
1254	hidnplayr	636
1159	hidnplayr	637
1514	hidnplayr	638	align 4
		639	.SYN_SENT:
1281	hidnplayr	640
1514	hidnplayr	641	DEBUGF 1,"TCP state: syn_sent\n"
1159	hidnplayr	642
1514	hidnplayr	643	test [edx + TCP_segment.Flags], TH_ACK
		644	jz @f
1281	hidnplayr	645
1514	hidnplayr	646	mov eax, [edx + TCP_segment.AckNumber]
		647	cmp eax, [ebx + TCP_SOCKET.ISS]
		648	jle .drop_with_reset
1281	hidnplayr	649
1514	hidnplayr	650	mov eax, [edx + TCP_segment.AckNumber]
		651	cmp eax, [ebx + TCP_SOCKET.SND_MAX]
		652	jg .drop_with_reset
		653	@@:
1281	hidnplayr	654
		655
1514	hidnplayr	656	test [edx + TCP_segment.Flags], TH_RST
		657	jz @f
1281	hidnplayr	658
1514	hidnplayr	659	test [edx + TCP_segment.Flags], TH_ACK
		660	jz .drop
1281	hidnplayr	661
1514	hidnplayr	662	;tp = tcp_drop(tp, ECONNREFUSED)
1159	hidnplayr	663
1514	hidnplayr	664	jmp .drop
		665	@@:
1159	hidnplayr	666
1514	hidnplayr	667	test [edx + TCP_segment.Flags], TH_SYN
		668	jz .drop
1318	hidnplayr	669
1514	hidnplayr	670	; now, process received SYN in response to an active open
		671	test [edx + TCP_segment.Flags], TH_ACK
		672	jz @f
		673
		674	mov eax, [edx + TCP_segment.AckNumber]
		675	mov [ebx + TCP_SOCKET.SND_UNA], eax
		676
		677	mov eax, [ebx + TCP_SOCKET.SND_UNA]
		678	cmp eax, [ebx + TCP_SOCKET.SND_NXT]
		679	jle @f
		680	mov [ebx + TCP_SOCKET.SND_NXT], eax
		681
		682
		683	; TODO: turn off retransmission timer
		684
		685	mov eax, [edx + TCP_segment.SequenceNumber]
		686	mov [ebx + TCP_SOCKET.IRS], eax
		687
		688	; TODO: set socket state to connected
		689
		690	mov [ebx + TCP_SOCKET.t_state], TCB_ESTABLISHED
		691
		692	; TODO: check if we should scale the connection (567-572)
		693	; TODO: update RTT estimators
		694
		695
		696	@@:
		697
		698	; We have received a syn but no ACK, so we are having a simultaneous open..
		699	mov [ebx + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
		700
		701	;-------------------------------------
		702	; Common processing for receipt of SYN
		703
		704	.trimthenstep6:
		705
		706	inc [edx + TCP_segment.SequenceNumber]
		707
		708	cmp cx, [ebx + TCP_SOCKET.RCV_WND]
		709	jle @f
		710
		711	movzx eax, cx
		712	sub ax, [ebx + TCP_SOCKET.RCV_WND]
		713	; TODO: 592
		714	mov cx, [ebx + TCP_SOCKET.RCV_WND]
		715	; TODO...
		716	@@:
		717	;;;;;
		718	;;; jmp .step6
		719
		720
		721
		722
		723
1274	hidnplayr	724	align 4
1514	hidnplayr	725	.trim_then_step6:
1159	hidnplayr	726
1514	hidnplayr	727	DEBUGF 1,"Trim, then step 6\n"
1159	hidnplayr	728
1514	hidnplayr	729	;----------------------------
		730	; trim any data not in window
1159	hidnplayr	731
1514	hidnplayr	732	mov eax, [ebx + TCP_SOCKET.RCV_NXT]
		733	sub eax, [edx + TCP_segment.SequenceNumber]
1318	hidnplayr	734
1514	hidnplayr	735	test eax, eax
		736	jz .no_drop
1274	hidnplayr	737
1514	hidnplayr	738	test [edx + TCP_segment.Flags], TH_SYN
		739	jz .no_drop
		740
		741	and [edx + TCP_segment.Flags], not (TH_SYN)
		742	inc [edx + TCP_segment.SequenceNumber]
		743
		744	cmp [edx + TCP_segment.UrgentPointer], 1
		745	jl @f
		746
		747	dec [edx + TCP_segment.UrgentPointer]
		748
		749	jmp .no_drop
		750	@@:
		751
		752	and [edx + TCP_segment.Flags], not (TH_URG)
		753	dec eax
		754
		755	.no_drop:
		756
		757	; eax holds number of bytes to drop
		758
		759
		760	;----------------------------------
		761	; Check for entire duplicate packet
		762
		763	cmp eax, ecx
		764	jge .duplicate
		765
		766	;;; TODO: figure 28.30
		767
		768	;; inc [TCP_segments_rx]
		769
		770	;; add dword [TCP_bytes_rx], ecx
		771	;; adc dword [TCP_bytes_rx+4], 0
		772
		773	;------------------------
		774	; Check for duplicate FIN
		775
		776	test [edx + TCP_segment.Flags], TH_FIN
		777	jz @f
		778	inc ecx
		779	cmp eax, ecx
		780	dec ecx
		781	jne @f
		782
		783	mov eax, ecx
		784	and [edx + TCP_segment.Flags], not TH_FIN
		785	;;; TODO: set ACKNOW flag
		786
		787	jmp .no_duplicate
		788	@@:
		789
		790	; Handle the case when a bound socket connects to itself
		791	; Allow packets with a SYN and an ACKto continue with the processing
		792
		793
		794	;-------------------------------------
		795	; Generate duplicate ACK if nescessary
		796
		797	; This code also handles simultaneous half-open or self-connects
		798
		799	test eax, eax
		800	jnz .drop_after_ack
		801
		802	cmp [edx + TCP_segment.Flags], TH_ACK
		803	jz .drop_after_ack
		804
		805	.duplicate:
		806
		807	;----------------------------------------
		808	; Update statistics for duplicate packets
		809
		810	;;; TODO
		811
		812	;;; DROP the packet ??
		813
		814	.no_duplicate:
		815
		816	;-----------------------------------------------
		817	; Remove duplicate data and update urgent offset
		818
		819	add [edx + TCP_segment.SequenceNumber], eax
		820
		821	;;; TODO
		822
		823	sub [edx + TCP_segment.UrgentPointer], ax
		824	jg @f
		825
		826	and [edx + TCP_segment.Flags], not (TH_URG)
		827	mov [edx + TCP_segment.UrgentPointer], 0
		828	@@:
		829
		830	;--------------------------------------------------
		831	; Handle data that arrives after process terminates
		832
		833	cmp [ebx + SOCKET.PID], 0
		834	jge @f
		835
		836	cmp [ebx + TCP_SOCKET.t_state], TCB_CLOSE_WAIT
		837	jle @f
		838
		839	test ecx, ecx
		840	jz @f
		841
		842	;;; Close the socket
		843	;;; update stats
		844
		845	jmp .drop_with_reset
		846
		847	@@:
		848
		849	;----------------------------------------
		850	; Remove data beyond right edge of window
		851
		852	mov eax, [edx + TCP_segment.SequenceNumber]
		853	add eax, ecx
		854	sub eax, [ebx + TCP_SOCKET.RCV_NXT]
		855	sub ax, [ebx + TCP_SOCKET.RCV_WND]
		856
		857	; eax now holds the number of bytes to drop
		858
		859	jle .no_excess_data
		860
		861	;;; TODO: update stats
		862
		863	cmp eax, ecx
		864	jl .dont_drop_all
		865
		866	;;; TODO 700-736
		867
		868	.dont_drop_all:
		869
		870	.no_excess_data:
		871
		872
		873	;-----------------
		874	; Record timestamp
		875
		876	;;; TODO 737-746
		877
		878	;------------------
		879	; Process RST flags
		880
		881	test [edx + TCP_segment.Flags], TH_RST
		882	jz .rst_skip
		883
		884	mov eax, [ebx + TCP_SOCKET.t_state]
		885	shl eax, 2
		886	jmp dword [eax + .rst_sw_list]
		887
		888	.rst_sw_list:
		889	dd .rst_skip ;TCB_CLOSED
		890	dd .rst_skip ;TCB_LISTEN
		891	dd .rst_skip ;TCB_SYN_SENT
		892	dd .econnrefused ;TCB_SYN_RECEIVED
		893	dd .econnreset ;TCB_ESTABLISHED
		894	dd .econnreset ;TCB_CLOSE_WAIT
		895	dd .econnreset ;TCB_FIN_WAIT_1
		896	dd .rst_close ;TCB_CLOSING
		897	dd .rst_close ;TCB_LAST_ACK
		898	dd .econnreset ;TCB_FIN_WAIT_2
		899	dd .rst_close ;TCB_TIMED_WAIT
		900
		901	.econnrefused:
		902
		903	;;; TODO: debug info
		904
		905	jmp .close
		906
		907	.econnreset:
		908
		909	;;; TODO: debug info
		910	.close:
		911
		912	;;; update stats
		913
		914	.rst_close:
		915
		916	;;; Close the socket
		917	jmp .drop
		918
		919	.rst_skip:
		920
		921	;--------------------------------------
		922	; handle SYN-full and ACK-less segments
		923
		924	test [edx + TCP_segment.Flags], TH_SYN
		925	jz @f
		926
		927	;;; tcp_drop ( ECONNRESET)
		928	jmp .drop_with_reset
		929
		930	test [edx + TCP_segment.Flags], TH_ACK
		931	jz .drop
		932
		933	;----------------
		934	; Process the ACK
		935
		936	cmp [ebx + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
		937	jg .ack_dup
		938	jl .ack_nodup
		939
		940	; dd .ack_nodup ;TCB_CLOSED
		941	; dd .ack_nodup ;TCB_LISTEN
		942	; dd .ack_nodup ;TCB_SYN_SENT
		943	; dd .ack_syn_rcvd ;TCB_SYN_RECEIVED
		944	; dd .ack_dup ;TCB_ESTABLISHED
		945	; dd .ack_dup ;TCB_CLOSE_WAIT
		946	; dd .ack_dup ;TCB_FIN_WAIT_1
		947	; dd .ack_dup ;TCB_CLOSING
		948	; dd .ack_dup ;TCB_LAST_ACK
		949	; dd .ack_dup ;TCB_FIN_WAIT_2
		950	; dd .ack_dup ;TCB_TIMED_WAIT
		951
		952	;;;;;
		953
		954	.ack_dup:
		955
		956	;;;;
		957
		958	.ack_nodup:
		959
		960	;;;; 887
		961
		962	;-------------------------------------------------
		963	; If the congestion window was infalted to account
		964	; for the other side's cached packets, retrace it
		965
		966	;;;; 888 - 902
		967
		968
		969	;------------------------------------------
		970	; RTT measurements and retransmission timer
		971
		972	;;;;; 903 - 926
		973
		974
		975	;-------------------------------------------
		976	; Open congestion window in response to ACKs
		977
		978	;;;;
		979
		980
		981	;------------------------------------------
		982	; Remove acknowledged data from send buffer
		983
		984	;;;; 943 - 956
		985
		986	;---------------------------------------
		987	; Wake up process waiting on send buffer
		988
		989	;;;;;
		990
		991	mov eax, [ebx + TCP_SOCKET.t_state]
		992	shl eax, 2
		993	jmp dword [eax + .ACK_sw_list]
		994
		995	.ACK_sw_list:
		996	dd .step6 ;TCB_CLOSED
		997	dd .step6 ;TCB_LISTEN
		998	dd .step6 ;TCB_SYN_SENT
		999	dd .step6 ;TCB_SYN_RECEIVED
		1000	dd .step6 ;TCB_ESTABLISHED
		1001	dd .step6 ;TCB_CLOSE_WAIT
		1002	dd ._963 ;TCB_FIN_WAIT_1
		1003	dd ._958 ;TCB_CLOSING
		1004	dd ._999 ;TCB_LAST_ACK
		1005	dd .step6 ;TCB_FIN_WAIT_2
		1006	dd ._1010 ;TCB_TIMED_WAIT
		1007
		1008
		1009	._963:
		1010
		1011
		1012	jmp .step6
		1013
		1014
		1015	._958:
		1016
		1017	jmp .step6
		1018
		1019	._999:
		1020
		1021	jmp .step6
		1022
		1023
		1024	._1010:
		1025
		1026	jmp .step6
		1027
		1028
		1029
		1030	align 4
		1031	.step6:
		1032
		1033	DEBUGF 1,"step 6\n"
		1034
		1035	;--------------------------
		1036	; update window information
		1037
		1038	test [edx + TCP_segment.Flags], TH_ACK
		1039	jz .no_window_update
		1040
		1041	mov eax, [ebx + TCP_SOCKET.SND_WL1]
		1042	cmp eax, [edx + TCP_segment.SequenceNumber]
		1043
		1044	;;;; 1021
		1045
		1046	;----------------------------------
		1047	; Keep track of pure window updates
		1048
		1049	test ecx, ecx
		1050	jz @f
		1051
		1052	mov eax, [ebx + TCP_SOCKET.SND_WL2]
		1053	cmp eax, [edx + TCP_segment.AckNumber]
		1054	jne @f
		1055
		1056	;; mov eax, tiwin
		1057	cmp eax, [ebx + TCP_SOCKET.SND_WND]
		1058	jle @f
		1059
		1060	;;; update stats
		1061
		1062	@@:
		1063
		1064	;; mov eax, incoming window
		1065	cmp eax, [ebx + TCP_SOCKET.max_sndwnd]
		1066	jle @f
		1067	mov [ebx + TCP_SOCKET.max_sndwnd], eax
		1068	@@:
		1069	mov [ebx + TCP_SOCKET.SND_WND], eax
		1070
		1071	mov eax, [edx + TCP_segment.SequenceNumber]
		1072	mov [ebx + TCP_SOCKET.SND_WL1], eax
		1073
		1074	mov eax, [edx + TCP_segment.AckNumber]
		1075	mov [ebx + TCP_SOCKET.SND_WL2], eax
		1076
		1077	;;; needoutput = 1
		1078
		1079	.no_window_update:
		1080
		1081
		1082	;-----------------
		1083	; process URG flag
		1084
		1085	test [edx + TCP_segment.Flags], TH_URG
		1086	jz .not_urgent
		1087
		1088	cmp [edx + TCP_segment.UrgentPointer], 0
		1089	jz .not_urgent
		1090
		1091	cmp [ebx + TCP_SOCKET.t_state], TCB_TIMED_WAIT
		1092	je .not_urgent
		1093
		1094	; Ignore bogus urgent offsets
		1095
		1096	;;; 1040-1050
		1097
		1098	movzx eax, [edx + TCP_segment.UrgentPointer]
		1099	add eax, [ebx + SOCKET.SO_RCV.SB_CC]
		1100	cmp eax, SOCKET_MAXDATA
		1101	jle .not_urgent
		1102
		1103	mov [edx + TCP_segment.UrgentPointer], 0
		1104	and [edx + TCP_segment.Flags], not (TH_URG)
		1105	jmp .do_data
		1106
		1107	.not_urgent:
		1108
		1109	;--------------------------------------
		1110	; processing of received urgent pointer
		1111
		1112	;;; 1051-1093
		1113
		1114	align 4
		1115	.do_data:
		1116
		1117	DEBUGF 1,"Do data:\n"
		1118
		1119	; process the data in the segment
		1120
		1121	test [edx + TCP_segment.Flags], TH_FIN
		1122	jz .process_fin
		1123
		1124	test [ebx + TCP_SOCKET.t_state], TCB_FIN_WAIT_1 ;;;;;
		1125	jge .dont_do_data
		1126
		1127	DEBUGF 1,"Processing data in segment\n"
		1128
		1129	;;; NOW, process the data
		1130
		1131	jmp .final_processing
		1132
		1133
		1134	.dont_do_data:
		1135
		1136
		1137	;---------------
		1138	; FIN processing
		1139
		1140	.process_fin:
		1141
		1142	DEBUGF 1,"Processing FIN\n"
		1143
		1144	mov eax, [ebx + TCP_SOCKET.t_state]
		1145	shl eax, 2
		1146	jmp dword [eax + .FIN_sw_list]
		1147
		1148	.FIN_sw_list:
		1149	dd .no_fin ;TCB_CLOSED
		1150	dd .no_fin ;TCB_LISTEN
		1151	dd .no_fin ;TCB_SYN_SENT
		1152	dd ._1131 ;TCB_SYN_RECEIVED
		1153	dd ._1131 ;TCB_ESTABLISHED
		1154	dd .no_fin ;TCB_CLOSE_WAIT
		1155	dd ._1139 ;TCB_FIN_WAIT_1
		1156	dd .no_fin ;TCB_CLOSING
		1157	dd .no_fin ;TCB_LAST_ACK
		1158	dd ._1147 ;TCB_FIN_WAIT_2
		1159	dd ._1156 ;TCB_TIMED_WAIT
		1160
		1161
		1162
		1163	._1131:
		1164
		1165	._1139:
		1166
		1167	._1147:
		1168
		1169	._1156:
		1170
		1171
		1172	.no_fin:
		1173
		1174	;-----------------
		1175	; Final processing
		1176
		1177	.final_processing:
		1178
		1179	DEBUGF 1,"Final processing\n"
		1180
		1181	;;; if debug enabled, output packet
		1182
		1183	;test ;;;needoutput = 1
		1184	;jnz .outputnow
		1185
		1186	test [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
		1187	jz .ret
		1188
		1189	.outputnow:
		1190	call TCP_output
		1191
		1192	.ret:
		1193	mov [ebx + SOCKET.lock], 0
		1194
1274	hidnplayr	1195	call kernel_free
1514	hidnplayr	1196	ret 4
1274	hidnplayr	1197
1514	hidnplayr	1198	;------------------------------------------
		1199	; Generate an ACK, droping incoming segment
1274	hidnplayr	1200
1514	hidnplayr	1201	align 4
		1202	.drop_after_ack:
1274	hidnplayr	1203
1514	hidnplayr	1204	DEBUGF 1,"Drop after ACK\n"
1274	hidnplayr	1205
1514	hidnplayr	1206	test [edx + TCP_segment.Flags], TH_RST
		1207	jnz .drop
1274	hidnplayr	1208
1514	hidnplayr	1209	and [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
1274	hidnplayr	1210
1514	hidnplayr	1211	call TCP_output
1318	hidnplayr	1212
1514	hidnplayr	1213	mov [ebx + SOCKET.lock], 0
1274	hidnplayr	1214
1514	hidnplayr	1215	call kernel_free
		1216	ret 4
1274	hidnplayr	1217
1514	hidnplayr	1218
		1219	;-------------------------------------------
		1220	; Generate an RST, dropping incoming segment
		1221
		1222	align 4
		1223	.drop_with_reset:
		1224
		1225	DEBUGF 1,"Drop with reset\n"
		1226
		1227	test [edx + TCP_segment.Flags], TH_RST
		1228	jnz .drop
		1229
		1230	;;; if its a multicast/broadcast, also drop
		1231
		1232	test [edx + TCP_segment.Flags], TH_ACK
		1233	jnz .respond_ack
		1234
		1235	test [edx + TCP_segment.Flags], TH_SYN
		1236	jnz .respond_syn
		1237
		1238	mov [ebx + SOCKET.lock], 0
		1239
		1240	call kernel_free
		1241	ret 4
		1242
		1243	.respond_ack:
		1244
		1245	;;;;
		1246
		1247	call TCP_respond
		1248
		1249	jmp .destroy_new_socket
		1250
		1251
		1252	.respond_syn:
		1253
		1254	;;;;
		1255
		1256	call TCP_respond
		1257
		1258	jmp .destroy_new_socket
		1259
		1260	;-----
		1261	; Drop
		1262
		1263	align 4
		1264	.drop:
		1265
		1266	DEBUGF 1,"Dropping packet\n"
		1267
		1268	;;;; If debugging options are enabled, output the packet somwhere
		1269
		1270	.destroy_new_socket:
		1271
		1272	;;;; kill the newly created socket
		1273
		1274	mov [ebx + SOCKET.lock], 0
		1275
		1276	call kernel_free
		1277	ret 4
		1278
		1279
		1280
		1281	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		1282
		1283
		1284
		1285	;---------------------
1318	hidnplayr	1286	;
1514	hidnplayr	1287	; TCP_do_options
1318	hidnplayr	1288	;
1514	hidnplayr	1289	;-------------------
		1290
1318	hidnplayr	1291	align 4
1514	hidnplayr	1292	TCP_do_options:
1274	hidnplayr	1293
1514	hidnplayr	1294	DEBUGF 1,"TCP_do_options\n"
1274	hidnplayr	1295
1514	hidnplayr	1296	push eax
		1297	sub eax, 20
		1298	jz .no_options
1274	hidnplayr	1299
1514	hidnplayr	1300	lea esi, [edx + TCP_segment.Data]
1318	hidnplayr	1301
1514	hidnplayr	1302
		1303	;-------------------------------------------
		1304	; Begin the loop by checking for EOL and NOP
		1305
1318	hidnplayr	1306	.loop:
		1307
1514	hidnplayr	1308	cmp byte [esi], TCP_OPT_EOL ; end of option list?
		1309	jz .no_options
1318	hidnplayr	1310
1514	hidnplayr	1311	cmp byte [esi], TCP_OPT_NOP ; nop ?
		1312	;;; cmove edi, 1 ; if so, set option size to 1
		1313	jz .continue ; and continue scanning
1318	hidnplayr	1314
1514	hidnplayr	1315	;------------------
		1316	; We have an option
1318	hidnplayr	1317
1514	hidnplayr	1318	movzx edi, byte [esi + 1] ; get the length of this option in edi
1318	hidnplayr	1319
		1320
1514	hidnplayr	1321	;--------------------------------------
		1322	; Check for Maximum segment size option
1318	hidnplayr	1323
1514	hidnplayr	1324	cmp byte [esi], TCP_OPT_MAXSEG
		1325	jne .no_maxseg
1318	hidnplayr	1326
1514	hidnplayr	1327	cmp edi, 4 ; option length
		1328	jne .continue
1318	hidnplayr	1329
1514	hidnplayr	1330	test [edx + TCP_segment.Flags], TH_SYN
		1331	jz .continue
1318	hidnplayr	1332
1514	hidnplayr	1333	; Now parse the option...
1318	hidnplayr	1334
1514	hidnplayr	1335	jmp .continue
1318	hidnplayr	1336
1514	hidnplayr	1337	.no_maxseg:
1318	hidnplayr	1338
1514	hidnplayr	1339	;------------------------
		1340	; Check for Window option
1318	hidnplayr	1341
1514	hidnplayr	1342	cmp byte [esi], TCP_OPT_WINDOW
		1343	jne .no_window
1318	hidnplayr	1344
1514	hidnplayr	1345	cmp edi, 3 ; option length
		1346	jne .continue
1318	hidnplayr	1347
1514	hidnplayr	1348	test [edx + TCP_segment.Flags], TH_SYN
		1349	jz .continue
1318	hidnplayr	1350
1514	hidnplayr	1351	; ...
1318	hidnplayr	1352
1514	hidnplayr	1353	jmp .continue
1318	hidnplayr	1354
1514	hidnplayr	1355	.no_window:
1318	hidnplayr	1356
1514	hidnplayr	1357	;---------------------------
		1358	; Check for Timestamp option
1318	hidnplayr	1359
1514	hidnplayr	1360	cmp byte [esi], TCP_OPT_TIMESTAMP
		1361	jne .no_timestamp
1318	hidnplayr	1362
1514	hidnplayr	1363	cmp edi, 10 ; option length
		1364	jne .continue
1318	hidnplayr	1365
1514	hidnplayr	1366	; ...
		1367
		1368
		1369	jmp .continue
		1370
		1371	.no_timestamp:
		1372
		1373	;----------------------------------
		1374	; Future options may be placed here
		1375
		1376
		1377
		1378
		1379	;------------------------------
		1380	; Continue scanning for options
		1381
		1382	.continue:
		1383	add esi, edi
		1384	sub eax, edi
		1385	jg .loop
		1386
		1387	.no_options:
		1388
1318	hidnplayr	1389	pop eax
1514	hidnplayr	1390
1318	hidnplayr	1391	ret
		1392
1514	hidnplayr	1393
		1394
		1395
		1396	;---------------------------
		1397	;
		1398	; TCP_pull_out_of_band
		1399	;
		1400	; IN: eax =
		1401	; ebx = socket ptr
		1402	; edx = tcp packet ptr
		1403	;
		1404	; OUT: /
		1405	;
		1406	;---------------------------
		1407
		1408	align 4
		1409	TCP_pull_out_of_band:
		1410
		1411	DEBUGF 1,"TCP_pull_out_of_band\n"
		1412
		1413	;;;; 1282-1305
		1414
1318	hidnplayr	1415	ret
		1416
		1417
		1418
		1419
1514	hidnplayr	1420
		1421	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		1422
		1423
		1424
		1425
		1426
1318	hidnplayr	1427	;-----------------------------------------------------------------
		1428	;
1514	hidnplayr	1429	; TCP_output
1318	hidnplayr	1430	;
1514	hidnplayr	1431	; IN: eax = socket pointer
		1432	;; esi = ptr to data
		1433	;; ecx = number of data bytes
		1434	;
1318	hidnplayr	1435	; OUT: /
		1436	;
		1437	;-----------------------------------------------------------------
		1438	align 4
1514	hidnplayr	1439	TCP_output:
1318	hidnplayr	1440
1514	hidnplayr	1441	DEBUGF 1,"TCP_output, socket: %x\n", eax
1318	hidnplayr	1442
1514	hidnplayr	1443	; We'll detect the length of the data to be transmitted, and flags to be used
		1444	; If there is some data, or any critical controls to send (SYN / RST), then transmit
		1445	; Otherwise, investigate further
1318	hidnplayr	1446
1514	hidnplayr	1447	mov ebx, [eax + TCP_SOCKET.SND_MAX]
		1448	cmp ebx, [eax + TCP_SOCKET.SND_UNA]
		1449	jne .not_idle
1318	hidnplayr	1450
1514	hidnplayr	1451	mov ebx, [eax + TCP_SOCKET.t_idle]
		1452	cmp ebx, [eax + TCP_SOCKET.t_rxtcur]
		1453	jle .not_idle
1318	hidnplayr	1454
1514	hidnplayr	1455	; We have been idle for a while and no ACKS are expected to clock out any data we send..
		1456	; Slow start to get ack "clock" running again.
1318	hidnplayr	1457
1514	hidnplayr	1458	mov ebx, [eax + TCP_SOCKET.t_maxseg]
		1459	mov [eax + TCP_SOCKET.SND_CWND], ebx
1318	hidnplayr	1460
1514	hidnplayr	1461	.not_idle:
		1462	.again:
		1463	mov ebx, [eax + TCP_SOCKET.SND_NXT] ; calculate offset
		1464	sub ebx, [eax + TCP_SOCKET.SND_UNA] ;
1318	hidnplayr	1465
1514	hidnplayr	1466	mov ecx, [eax + TCP_SOCKET.SND_WND] ; determine window
		1467	cmp ecx, [eax + TCP_SOCKET.SND_CWND] ;
		1468	jl @f ;
		1469	mov ecx, [eax + TCP_SOCKET.SND_CWND] ;
		1470	@@: ;
1318	hidnplayr	1471
1514	hidnplayr	1472	call TCP_outflags
1318	hidnplayr	1473
1514	hidnplayr	1474	; If in persist timeout with window of 0, send 1 byte.
		1475	; Otherwise, if window is small but nonzero, and timer expired,
		1476	; we will send what we can and go to transmit state
1318	hidnplayr	1477
1514	hidnplayr	1478	test [eax + TCP_SOCKET.t_force], -1
		1479	jz .no_persist_timeout
1318	hidnplayr	1480
1514	hidnplayr	1481	test ecx, ecx
		1482	jnz .no_zero_window
1255	hidnplayr	1483
1514	hidnplayr	1484	cmp ebx, [eax + SOCKET.SO_SND.SB_CC]
		1485	jge @f
1255	hidnplayr	1486
1514	hidnplayr	1487	and dl, not (TH_FIN) ; clear the FIN flag ??? how can it be set before?
1255	hidnplayr	1488
1514	hidnplayr	1489	@@:
		1490	inc ecx
		1491	jmp .no_persist_timeout
1255	hidnplayr	1492
1514	hidnplayr	1493	.no_zero_window:
1254	hidnplayr	1494
1514	hidnplayr	1495	;;; mov [eax + TCP_SOCKET.t_timer....TCPT_PERSIST], 0
		1496	mov [eax + TCP_SOCKET.t_rxtshift], 0
1254	hidnplayr	1497
1514	hidnplayr	1498	.no_persist_timeout:
1159	hidnplayr	1499
1514	hidnplayr	1500	;;;106
1159	hidnplayr	1501
1514	hidnplayr	1502	mov esi, [eax + SOCKET.SO_SND.SB_CC]
		1503	cmp esi, ecx
		1504	jl @f
		1505	mov esi, ecx
		1506	@@:
		1507	sub esi, ebx
1254	hidnplayr	1508
1514	hidnplayr	1509	cmp esi, -1
		1510	jne .not_minus_one
1159	hidnplayr	1511
1514	hidnplayr	1512	; If FIN has been set, but not ACKed, and we havent been called to retransmit,
		1513	; len (esi) will be -1
		1514	; Otherwise, window shrank after we sent into it.
		1515	; If window shrank to 0, cancel pending retransmit and pull SND_NXT back to (closed) window
		1516	; We will enter persist state below.
		1517	; If window didn't close completely, just wait for an ACK
1159	hidnplayr	1518
1514	hidnplayr	1519	xor esi, esi
1159	hidnplayr	1520
1514	hidnplayr	1521	test ecx, ecx
		1522	jnz @f
1159	hidnplayr	1523
1514	hidnplayr	1524	;;; mov [eax + TCP_SOCKET.t_timer..TCPT_REXMT], 0
1274	hidnplayr	1525
1514	hidnplayr	1526	push [eax + TCP_SOCKET.SND_UNA]
		1527	pop [eax + TCP_SOCKET.SND_NXT]
		1528	@@:
1254	hidnplayr	1529
1514	hidnplayr	1530	.not_minus_one:
1254	hidnplayr	1531
1514	hidnplayr	1532	;;; 124
1159	hidnplayr	1533
1514	hidnplayr	1534	cmp esi, [eax + TCP_SOCKET.t_maxseg]
		1535	jle @f
1274	hidnplayr	1536
1514	hidnplayr	1537	mov esi, [eax + TCP_SOCKET.t_maxseg]
		1538	;sendalot = 1
1274	hidnplayr	1539
1514	hidnplayr	1540	@@:
1274	hidnplayr	1541
1514	hidnplayr	1542	;;; 128
1274	hidnplayr	1543
1514	hidnplayr	1544	mov edi, [eax + TCP_SOCKET.SND_NXT]
		1545	add edi, esi ; len
		1546	sub edi, [eax + TCP_SOCKET.SND_UNA]
		1547	add edi, [eax + SOCKET.SO_SND.SB_CC]
		1548	cmp edi, 0
		1549	jle @f
1274	hidnplayr	1550
1514	hidnplayr	1551	and dl, not (TH_FIN) ; clear the FIN flag
1159	hidnplayr	1552
1514	hidnplayr	1553	@@:
1159	hidnplayr	1554
		1555
1514	hidnplayr	1556	;;;; 130 TODO: set window (ecx) to space in send buffer
1159	hidnplayr	1557
		1558
1514	hidnplayr	1559	;------------------------------
		1560	; Sender silly window avoidance
1159	hidnplayr	1561
1514	hidnplayr	1562	test esi, esi
		1563	jz .zero_length
1159	hidnplayr	1564
1249	hidnplayr	1565
1514	hidnplayr	1566	cmp esi, [eax + TCP_SOCKET.t_maxseg]
		1567	je .send
1274	hidnplayr	1568
1514	hidnplayr	1569	;;; TODO: 144-145
1274	hidnplayr	1570
1514	hidnplayr	1571	test [eax + TCP_SOCKET.t_force], -1
		1572	jnz .send
1274	hidnplayr	1573
1514	hidnplayr	1574	;;; TODO: 149..152
1274	hidnplayr	1575
1514	hidnplayr	1576	.zero_length:
1254	hidnplayr	1577
		1578
1514	hidnplayr	1579	;----------------------------------------
		1580	; Check if a window update should be sent
1159	hidnplayr	1581
1514	hidnplayr	1582	cmp ecx, 0 ; window
		1583	jle .no_window
1159	hidnplayr	1584
1514	hidnplayr	1585	;;; TODO 154-172
1159	hidnplayr	1586
1514	hidnplayr	1587	.no_window:
1159	hidnplayr	1588
1514	hidnplayr	1589	;--------------------------
		1590	; Should a segment be sent?
1159	hidnplayr	1591
1514	hidnplayr	1592	test [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
		1593	jnz .send
1159	hidnplayr	1594
1514	hidnplayr	1595	test dl, TH_SYN + TH_RST
		1596	jnz .send
1159	hidnplayr	1597
1514	hidnplayr	1598	mov eax, [ebx + TCP_SOCKET.SND_UP]
		1599	cmp eax, [ebx + TCP_SOCKET.SND_UNA]
		1600	jg .send
1249	hidnplayr	1601
1514	hidnplayr	1602	test dl, TH_FIN
		1603	jz .enter_persist
1318	hidnplayr	1604
1514	hidnplayr	1605	test [ebx + TCP_SOCKET.t_flags], TF_SENTFIN
		1606	jnz .send
1254	hidnplayr	1607
1514	hidnplayr	1608	mov eax, [ebx + TCP_SOCKET.SND_NXT]
		1609	cmp eax, [ebx + TCP_SOCKET.SND_UNA]
		1610	je .send
1254	hidnplayr	1611
1514	hidnplayr	1612	;--------------------
		1613	; Enter persist state
1318	hidnplayr	1614
1514	hidnplayr	1615	.enter_persist:
1318	hidnplayr	1616
1514	hidnplayr	1617	DEBUGF 1,"Entering pesist state\n"
1318	hidnplayr	1618
		1619
		1620
1514	hidnplayr	1621	;--------------------------------------
		1622	; No reason to send a segment, just ret
1318	hidnplayr	1623
1514	hidnplayr	1624	DEBUGF 1,"No reason to send a segment\n"
1318	hidnplayr	1625
1514	hidnplayr	1626	ret
1318	hidnplayr	1627
		1628
		1629
		1630
		1631
1514	hidnplayr	1632	;-----------------------------------------------
		1633	;
		1634	; Send a segment
		1635	;
		1636	; ebx = socket pointer
		1637	; dl = flags
		1638	;
		1639	;-----------------------------------------------
1318	hidnplayr	1640
1514	hidnplayr	1641	.send:
1318	hidnplayr	1642
1514	hidnplayr	1643	DEBUGF 1,"Preparing to send a segment\n"
1318	hidnplayr	1644
1514	hidnplayr	1645	xor edi, edi ; edi will contain the number of header option bytes
1318	hidnplayr	1646
1514	hidnplayr	1647	;------------------------------------
		1648	; Send options with first SYN segment
1318	hidnplayr	1649
1514	hidnplayr	1650	test dl, TH_SYN
		1651	jz .no_options
1318	hidnplayr	1652
1514	hidnplayr	1653	mov eax, [ebx + TCP_SOCKET.ISS]
		1654	mov [ebx + TCP_SOCKET.SND_NXT], eax
1318	hidnplayr	1655
1514	hidnplayr	1656	test [ebx + TCP_SOCKET.t_flags], TF_NOOPT
		1657	jnz .no_options
1318	hidnplayr	1658
1514	hidnplayr	1659	mov eax, TCP_OPT_MAXSEG shl 24 + 4 shl 16
		1660	mov ax, 1280 ;;;;;;
1318	hidnplayr	1661	bswap eax
1514	hidnplayr	1662	push eax
		1663
		1664	mov di, 4
		1665
		1666	test [ebx + TCP_SOCKET.t_flags], TF_REQ_SCALE
		1667	jz .no_syn
		1668
		1669	test dl, TH_ACK
		1670	jnz .scale_opt
		1671
		1672	test [ebx + TCP_SOCKET.t_flags], TF_RCVD_SCALE
		1673	jz .no_syn
		1674
		1675	.scale_opt:
		1676
		1677	mov eax, TCP_OPT_WINDOW shl 24 + 4 shl 16 + TCP_OPT_NOP
		1678	mov ah, byte [ebx + TCP_SOCKET.request_r_scale]
1318	hidnplayr	1679	bswap eax
1514	hidnplayr	1680	push eax
1255	hidnplayr	1681
1514	hidnplayr	1682	add di, 4
1159	hidnplayr	1683
1514	hidnplayr	1684	.no_syn:
1159	hidnplayr	1685
1514	hidnplayr	1686	;------------------------------------
		1687	; Make the timestamp option if needed
1159	hidnplayr	1688
1514	hidnplayr	1689	test [ebx + TCP_SOCKET.t_flags], TF_REQ_TSTMP
		1690	jz .no_timestamp
1159	hidnplayr	1691
1514	hidnplayr	1692	test dl, TH_RST
		1693	jnz .no_timestamp
		1694
		1695	test dl, TH_ACK
		1696	jz .timestamp
		1697
		1698	test [ebx + TCP_SOCKET.t_flags], TF_RCVD_TSTMP
		1699	jz .no_timestamp
		1700
		1701	.timestamp:
		1702
		1703	DEBUGF 1,"Creating a timestamp\n"
		1704
		1705	push dword (TCP_OPT_TIMESTAMP shl 8 + 10 + TCP_OPT_NOP shl 16 + TCP_OPT_NOP shl 24)
		1706	pushw 0
		1707	mov eax, [timer_ticks]
		1708	bswap eax
		1709	push eax
		1710
		1711	add di, 10
		1712
		1713	.no_timestamp:
		1714
		1715	;; TODO: check if we dont exceed the max segment size
		1716
		1717	.no_options:
		1718	add edi, TCP_segment.Data
		1719
		1720	;-----------------------------------
		1721	; Check if we have some data to send
		1722
		1723	;;; mov ecx, [huppeldepup]
		1724
1255	hidnplayr	1725	test ecx, ecx
1514	hidnplayr	1726	jz .no_data
1159	hidnplayr	1727
1514	hidnplayr	1728	;;; 278-316
1281	hidnplayr	1729
1514	hidnplayr	1730	jmp .header
1281	hidnplayr	1731
1514	hidnplayr	1732	.no_data:
1159	hidnplayr	1733
1514	hidnplayr	1734	;;; 317-338
1281	hidnplayr	1735
		1736
1514	hidnplayr	1737	;----------
		1738
		1739	push di dx ebx
		1740
		1741	add ecx, edi ; total TCP segment size
		1742
		1743	mov eax, [ebx + IP_SOCKET.RemoteIP]
		1744	mov ebx, [ebx + IP_SOCKET.LocalIP]
		1745	mov di , IP_PROTO_TCP
		1746	call IPv4_create_packet
		1747
		1748	;;;; jz .fail
		1749
		1750	push edx eax
		1751	call NET_send
1159	hidnplayr	1752	ret
		1753
1514	hidnplayr	1754	;----------------
1159	hidnplayr	1755
1249	hidnplayr	1756
1514	hidnplayr	1757	;-------------------------------
		1758	; Now, create the 20-byte header
1274	hidnplayr	1759
1514	hidnplayr	1760	.header:
1274	hidnplayr	1761
1514	hidnplayr	1762	;-----------------------
		1763	; Fill in the TCP header
		1764	pop esi
1274	hidnplayr	1765
1514	hidnplayr	1766	push [esi + TCP_SOCKET.SND_NXT]
		1767	rol word [esp], 8
		1768	rol dword [esp], 16
		1769	pop [edi + TCP_segment.SequenceNumber]
1274	hidnplayr	1770
1514	hidnplayr	1771	push [esi + TCP_SOCKET.RCV_NXT]
		1772	rol word [esp], 8
		1773	rol dword [esp], 16
		1774	pop [edi + TCP_segment.AckNumber]
1274	hidnplayr	1775
1514	hidnplayr	1776	push [esi + TCP_SOCKET.LocalPort]
		1777	rol word [esp], 8
		1778	pop [edi + TCP_segment.SourcePort]
1274	hidnplayr	1779
1514	hidnplayr	1780	push [esi + TCP_SOCKET.RemotePort]
		1781	rol word [esp], 8
		1782	pop [edi + TCP_segment.DestinationPort]
1254	hidnplayr	1783
		1784
1514	hidnplayr	1785	mov [edi + TCP_segment.Window], 0x0005
		1786	; 1280 bytes
		1787	mov [edi + TCP_segment.UrgentPointer], 0
1159	hidnplayr	1788
1514	hidnplayr	1789	mov [edi + TCP_segment.DataOffset], 0x50
1159	hidnplayr	1790
1514	hidnplayr	1791	mov [edi + TCP_segment.Flags], cl
1159	hidnplayr	1792
1514	hidnplayr	1793	mov [edi + TCP_segment.Checksum], 0
1159	hidnplayr	1794
1514	hidnplayr	1795	;-----
1159	hidnplayr	1796
		1797
1514	hidnplayr	1798	;--------------
		1799	; Copy the data
1159	hidnplayr	1800
1514	hidnplayr	1801	pop esi
		1802	push edi
		1803	add edi, TCP_segment.Data ;;
		1804	sub ecx, TCP_segment.Data ;;;
1249	hidnplayr	1805
1514	hidnplayr	1806	shr ecx, 1
		1807	jnc .nb
		1808	movsb
		1809	.nb:
		1810	shr ecx, 1
		1811	jnc .nw
		1812	movsw
		1813	.nw:
		1814	test ecx, ecx
		1815	jz .nd
		1816	rep movsd
		1817	.nd:
		1818	pop edi
1254	hidnplayr	1819
1514	hidnplayr	1820	;--------------------
		1821	; Create the checksum
1254	hidnplayr	1822
1514	hidnplayr	1823	push [ebx + IP_SOCKET.LocalIP]
		1824	push [ebx + IP_SOCKET.RemoteIP]
		1825	call TCP_checksum
1159	hidnplayr	1826
1514	hidnplayr	1827	;----------------
		1828	; Send the packet
1159	hidnplayr	1829
1514	hidnplayr	1830	;;;;;
1159	hidnplayr	1831
1514	hidnplayr	1832
		1833	DEBUGF 1,"Sending TCP Packet to device %x\n", ebx
		1834	mov esi, [ebx + ETH_DEVICE.transmit]
		1835
1159	hidnplayr	1836	ret
		1837
		1838
1249	hidnplayr	1839
1514	hidnplayr	1840	;-------------------------
		1841	;
		1842	; TCP_outflags
		1843	;
		1844	; IN: eax = socket ptr
		1845	;
		1846	; OUT: edx = flags
		1847	;
		1848	;-------------------------
1249	hidnplayr	1849	align 4
1514	hidnplayr	1850	TCP_outflags:
1254	hidnplayr	1851
1514	hidnplayr	1852	mov edx, [eax + TCP_SOCKET.t_state]
		1853	movzx edx, byte [edx + .flaglist]
1254	hidnplayr	1854
1514	hidnplayr	1855	DEBUGF 1,"TCP_outflags, socket: %x, flags: %x\n", eax, dl
		1856
1159	hidnplayr	1857	ret
		1858
1514	hidnplayr	1859	.flaglist:
1159	hidnplayr	1860
1514	hidnplayr	1861	db TH_RST + TH_ACK ; TCB_CLOSED
		1862	db 0 ; TCB_LISTEN
		1863	db TH_SYN ; TCB_SYN_SENT
		1864	db TH_SYN + TH_ACK ; TCB_SYN_RECEIVED
		1865	db TH_ACK ; TCB_ESTABLISHED
		1866	db TH_ACK ; TCB_CLOSE_WAIT
		1867	db TH_SYN + TH_ACK ; TCB_FIN_WAIT_1
		1868	db TH_SYN + TH_ACK ; TCB_CLOSING
		1869	db TH_SYN + TH_ACK ; TCB_LAST_ACK
		1870	db TH_ACK ; TCB_FIN_WAIT_2
		1871	db TH_ACK ; TCB_TIMED_WAIT
1249	hidnplayr	1872
1514	hidnplayr	1873
		1874	;-------------------------
		1875	;
		1876	; TCP_drop
		1877	;
		1878	; IN: eax = socket ptr
		1879	;
		1880	; OUT: /
		1881	;
		1882	;-------------------------
1249	hidnplayr	1883	align 4
1514	hidnplayr	1884	TCP_drop:
1254	hidnplayr	1885
1514	hidnplayr	1886	DEBUGF 1,"TCP_drop\n"
1254	hidnplayr	1887
1514	hidnplayr	1888	; cmp [eax + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
		1889	; jl .no_syn_received
1159	hidnplayr	1890
1514	hidnplayr	1891	mov [eax + TCP_SOCKET.t_state], TCB_CLOSED
1159	hidnplayr	1892
1514	hidnplayr	1893	call TCP_output
1254	hidnplayr	1894
1514	hidnplayr	1895	; .no_syn_received:
		1896
1159	hidnplayr	1897	ret
		1898
		1899
1254	hidnplayr	1900
		1901
1159	hidnplayr	1902
1514	hidnplayr	1903	;---------------------------------------
		1904	;
		1905	; TCP_respond
		1906	;
		1907	; The easy way to send a RST/ACK segment
		1908	;
		1909	; IN: eax = socket ptr
		1910	;
		1911	; OUT: /
		1912	;
		1913	;---------------------------------------
		1914	align 4
		1915	TCP_respond:
1254	hidnplayr	1916
1514	hidnplayr	1917	DEBUGF 1,"TCP_respond\n"
1159	hidnplayr	1918
		1919	ret
		1920
		1921
1514	hidnplayr	1922
		1923	;-----------------------------------------------------------------
		1924	;
		1925	; TCP_checksum
		1926	;
		1927	; This is the fast procedure to create or check a UDP header
		1928	; - To create a new checksum, the checksum field must be set to 0 before computation
		1929	; - To check an existing checksum, leave the checksum as is,
		1930	; and it will be 0 after this procedure, if it was correct
		1931	;
		1932	; IN: push source ip
		1933	; push dest ip
		1934	;
		1935	; esi = packet ptr
		1936	;
		1937	; OUT: checksum is filled in in packet! (but also in dx)
		1938	;
		1939	;-----------------------------------------------------------------
1249	hidnplayr	1940	align 4
1514	hidnplayr	1941	TCP_checksum:
1254	hidnplayr	1942
1514	hidnplayr	1943	;-------------
		1944	; Pseudoheader
1254	hidnplayr	1945
1514	hidnplayr	1946	; protocol type
		1947	mov edx, IP_PROTO_TCP ; NO shl 8 here ! (it took me ages to figure this one out)
1254	hidnplayr	1948
1514	hidnplayr	1949	; source address
		1950	add dl, [esp+1+4]
		1951	adc dh, [esp+0+4]
		1952	adc dl, [esp+3+4]
		1953	adc dh, [esp+2+4]
1159	hidnplayr	1954
1514	hidnplayr	1955	; destination address
		1956	adc dl, [esp+1+8]
		1957	adc dh, [esp+0+8]
		1958	adc dl, [esp+3+8]
		1959	adc dh, [esp+2+8]
1159	hidnplayr	1960
1514	hidnplayr	1961	; size
		1962	adc dl, cl
		1963	adc dh, ch
1254	hidnplayr	1964
1514	hidnplayr	1965	;---------------------
		1966	; Real header and data
1254	hidnplayr	1967
1514	hidnplayr	1968	push esi
		1969	call checksum_1
		1970	call checksum_2
		1971	pop esi
1254	hidnplayr	1972
1514	hidnplayr	1973	neg [esi+UDP_Packet.Checksum] ; zero will stay zero so we just get the checksum
		1974	add [esi+UDP_Packet.Checksum], dx ; , else we will get (new checksum - old checksum) in the end, wich should be 0 :)
1159	hidnplayr	1975
1514	hidnplayr	1976	ret 8 ; Remove the IPs from stack
1159	hidnplayr	1977
		1978
1514	hidnplayr	1979
		1980
1254	hidnplayr	1981	;---------------------------------------------------------------------------
		1982	;
		1983	; TCP_API
		1984	;
		1985	; This function is called by system function 75
		1986	;
		1987	; IN: subfunction number in bl
		1988	; device number in bh
		1989	; ecx, edx, .. depends on subfunction
		1990	;
		1991	; OUT:
		1992	;
		1993	;---------------------------------------------------------------------------
		1994	align 4
		1995	TCP_API:
		1996
		1997	movzx eax, bh
		1998	shl eax, 2
		1999
		2000	test bl, bl
		2001	jz .packets_tx ; 0
		2002	dec bl
		2003	jz .packets_rx ; 1
		2004
		2005	.error:
		2006	mov eax, -1
		2007	ret
		2008
		2009	.packets_tx:
1514	hidnplayr	2010	add eax, TCP_segments_tx
1254	hidnplayr	2011	mov eax, [eax]
		2012	ret
		2013
		2014	.packets_rx:
1514	hidnplayr	2015	add eax, TCP_segments_rx
1254	hidnplayr	2016	mov eax, [eax]
		2017	ret

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(root)/kernel/branches/net/network/tcp.inc @ 1542 – Rev 1514