;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; Copyright (C) KolibriOS team 2004-2010. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License ;;
;; ;;
;; TCP.INC ;;
;; ;;
;; Part of the tcp/ip network stack for KolibriOS ;;
;; ;;
;; Written by hidnplayr@kolibrios.org ;;
;; ;;
;; Based on the code of 4.4BSD ;;
;; ;;
;; GNU GENERAL PUBLIC LICENSE ;;
;; Version 2, June 1991 ;;
;; ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
$Revision: 1519 $
; Socket states
TCB_CLOSED equ 0
TCB_LISTEN equ 1
TCB_SYN_SENT equ 2
TCB_SYN_RECEIVED equ 3
TCB_ESTABLISHED equ 4
TCB_CLOSE_WAIT equ 5
TCB_FIN_WAIT_1 equ 6
TCB_CLOSING equ 7
TCB_LAST_ACK equ 8
TCB_FIN_WAIT_2 equ 9
TCB_TIMED_WAIT equ 10
; Socket Flags
TF_ACKNOW equ 1 shl 0 ; ack peer immediately
TF_DELACK equ 1 shl 1 ; ack, but try to delay it
TF_NODELAY equ 1 shl 2 ; don't delay packets to coalesce
TF_NOOPT equ 1 shl 3 ; don't use tcp options
TF_SENTFIN equ 1 shl 4 ; have sent FIN
TF_REQ_SCALE equ 1 shl 5 ; have/will request window scaling
TF_RCVD_SCALE equ 1 shl 6 ; other side has requested scaling
TF_REQ_TSTMP equ 1 shl 7 ; have/will request timestamps
TF_RCVD_TSTMP equ 1 shl 8 ; a timestamp was received in SYN
TF_SACK_PERMIT equ 1 shl 9 ; other side said I could SACK
; Segment flags
TH_FIN equ 1 shl 0
TH_SYN equ 1 shl 1
TH_RST equ 1 shl 2
TH_PUSH equ 1 shl 3
TH_ACK equ 1 shl 4
TH_URG equ 1 shl 5
; Segment header options
TCP_OPT_EOL equ 0 ; End of option list.
TCP_OPT_NOP equ 1 ; No-Operation.
TCP_OPT_MAXSEG equ 2 ; Maximum Segment Size.
TCP_OPT_WINDOW equ 3 ; window scale
TCP_OPT_TIMESTAMP equ 8
; Fundamental timer values
TCP_time_MSL equ 47 ; max segment lifetime (30s)
TCP_time_re_min equ 2 ; min retransmission (1,28s)
TCP_time_re_max equ 100 ; max retransmission (64s)
TCP_time_pers_min equ 8 ; min persist (5,12s)
TCP_time_pers_max equ 94 ; max persist (60,16s)
TCP_time_keep_init equ 118 ; connectione stablishment (75,52s)
TCP_time_keep_idle equ 4608 ; idle time before 1st probe (2h)
TCP_time_keep_interval equ 118 ; between probes when no response (75,52s)
TCP_time_rtt_default equ 5 ; default Round Trip Time (3,2s)
; timer constants
TCP_max_rxtshift equ 12 ; max retransmissions waiting for ACK
TCP_max_keepcnt equ 8 ; max keepalive probes
struct TCP_segment
.SourcePort dw ?
.DestinationPort dw ?
.SequenceNumber dd ?
.AckNumber dd ?
.DataOffset db ? ; DataOffset[0-3 bits] and Reserved[4-7]
.Flags db ? ; Reserved[0-1 bits]|URG|ACK|PSH|RST|SYN|FIN
.Window dw ?
.Checksum dw ?
.UrgentPointer dw ?
.Data: ; ..or options
ends
struct tcp_in_queue_entry
.data_ptr dd ?
.data_size dd ?
.offset dd ?
.size:
ends
struct tcp_out_queue_entry
.data_ptr dd ?
.data_size dd ?
.size:
ends
align 4
uglobal
TCP_segments_tx rd IP_MAX_INTERFACES
TCP_segments_rx rd IP_MAX_INTERFACES
TCP_bytes_rx rq IP_MAX_INTERFACES
TCP_bytes_tx rq IP_MAX_INTERFACES
TCP_sequence_num dd ?
endg
;-----------------------------------------------------------------
;
; TCP_init
;
; This function resets all TCP variables
;
; IN: /
; OUT: /
;
;-----------------------------------------------------------------
align 4
TCP_init:
xor eax, eax
mov edi, TCP_segments_tx
mov ecx, (6*IP_MAX_INTERFACES)
rep stosd
mov [TCP_sequence_num], 1
ret
;----------------------
;
;
;----------------------
align 4
TCP_timer_160ms:
mov eax, net_sockets
.loop:
mov eax, [eax + SOCKET.NextPtr]
or eax, eax
jz .exit
cmp [eax + SOCKET.Type], IP_PROTO_TCP
jne .loop
dec [eax + TCP_SOCKET.timer_ack]
jnz .loop
DEBUGF 1,"TCP ack for socket %x expired, time to piggyback!\n", eax
push eax
call TCP_respond
pop eax
jmp .loop
.exit:
ret
;-----------------------------------------------------------------
;
;
;-----------------------------------------------------------------
align 4
TCP_timer_640ms:
; Update TCP sequence number
add [TCP_sequence_num], 64000
; scan through all the active TCP sockets, decrementing ALL timers
; timers do not have the chance to wrap because of the keepalive timer will kill the socket when it expires
mov eax, net_sockets
.loop:
mov eax, [eax + SOCKET.NextPtr]
.check_only:
or eax, eax
jz .exit
cmp [eax + SOCKET.Type], IP_PROTO_TCP
jne .loop
dec [eax + TCP_SOCKET.timer_retransmission]
jnz .check_more2
DEBUGF 1,"socket %x: Retransmission timer expired\n", eax
push eax
call TCP_output
pop eax
.check_more2:
dec [eax + TCP_SOCKET.timer_keepalive]
jnz .check_more3
DEBUGF 1,"socket %x: Keepalive expired\n", eax
;;; TODO: check socket state and handle accordingly
.check_more3:
dec [eax + TCP_SOCKET.timer_timed_wait]
jnz .check_more5
DEBUGF 1,"socket %x: 2MSL timer expired\n", eax
.check_more5:
dec [eax + TCP_SOCKET.timer_persist]
jnz .loop
DEBUGF 1,"socket %x: persist timer expired\n", eax
jmp .loop
.exit:
ret
;-----------------------------------------------------------------
;
; TCP_input:
;
; IN: [esp] = ptr to buffer
; [esp+4] = buffer size
; ebx = ptr to device struct
; ecx = segment size
; edx = ptr to TCP segment
;
; esi = ipv4 source address
; edi = ipv4 dest address
;
; OUT: /
;
;-----------------------------------------------------------------
align 4
TCP_input:
DEBUGF 1,"TCP_input\n"
; 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.
movzx eax, [edx + TCP_segment.DataOffset]
and eax, 0xf0
shr al , 2
DEBUGF 1,"data offset: %u\n", eax
cmp eax, 20
jl .drop
cmp eax, ecx
jg .drop
;-------------------------------
; Now, re-calculate the checksum
push eax edx ebx
push edi
push esi
mov esi, edx
call TCP_checksum ; this destroys edx, ecx and esi (but not edi! :)
pop ebx edx eax
cmp [edx + TCP_segment.Checksum], 0
jnz .drop
DEBUGF 1,"Checksum is correct\n"
;-----------------------------------------------------------------------------------------
; Check if this packet has a timestamp option (We do it here so we can process it quickly)
cmp eax, 20 + 12 ; Timestamp option is 12 bytes
jl .no_timestamp
je .is_ok
cmp byte [edx + TCP_segment.Data + 12], 0 ; end of option list
jne .no_timestamp
.is_ok:
test [edx + TCP_segment.Flags], TH_SYN ; SYN flag must not be set
jnz .no_timestamp
cmp dword [edx + TCP_segment.Data], 0x0101080a ; Timestamp header
jne .no_timestamp
DEBUGF 1,"timestamp ok\n"
; TODO: Parse the options
; TODO: Set a Bit in the TCP to tell all options are parsed
ret
.no_timestamp:
;-------------------------------------------
; Convert Big-endian values to little endian
ntohld [edx + TCP_segment.SequenceNumber]
ntohld [edx + TCP_segment.AckNumber]
ntohlw [edx + TCP_segment.Window]
ntohlw [edx + TCP_segment.UrgentPointer]
;------------------------------------------------------------
; Next thing to do is find the TCB (thus, the socket pointer)
; IP Packet TCP Destination Port = local Port
; (IP Packet SenderAddress = Remote IP) OR (Remote IP = 0)
; (IP Packet TCP Source Port = remote Port) OR (remote Port = 0)
mov ebx, net_sockets
.socket_loop:
mov ebx, [ebx + SOCKET.NextPtr]
or ebx, ebx
jz .drop_with_reset
cmp [ebx + SOCKET.Type], IP_PROTO_TCP
jne .socket_loop
mov ax, [edx + TCP_segment.DestinationPort]
cmp [ebx + TCP_SOCKET.LocalPort], ax
jne .socket_loop
mov eax, [ebx + IP_SOCKET.RemoteIP]
cmp eax, esi
je @f
test eax, eax
jnz .socket_loop
@@:
mov ax, [ebx + TCP_SOCKET.RemotePort]
cmp [edx + TCP_segment.SourcePort] , ax
je .found_socket
test ax, ax
jnz .socket_loop
.found_socket:
DEBUGF 1,"Socket ptr: %x\n", ebx
; ebx now contains the pointer to the socket
;----------------------------
; Check if socket isnt closed
cmp [TCP_SOCKET.t_state], TCB_CLOSED
je .drop
;----------------
; Lock the socket
add ebx, SOCKET.lock ; TODO: figure out if we should lock now already
call wait_mutex
sub ebx, SOCKET.lock
;---------------------------------------
; unscale the window into a 32 bit value ;;;;;;
movzx eax, [edx + TCP_segment.Window]
xchg al, ah
test [edx + TCP_segment.Flags], TH_SYN
jnz .no_syn
mov cl , [ebx + TCP_SOCKET.SND_SCALE]
shl eax, cl
.no_syn:
;-----------------------------------
; Is this socket a listening socket?
; If so, create a new socket
test [ebx + SOCKET.options], SO_ACCEPTCON
jz .no_accept_conn
; TODO: create a new socket
.no_accept_conn:
;----------------------------
; Compute window scale factor
; TODO
;-------------------------------------
; Reset idle timer and keepalive timer
;;;; TODO: idle timer?
mov [ebx + TCP_SOCKET.timer_keepalive], TCP_time_keep_interval
;-----------------------------------------
; Process TCP options if not in LISTEN state
test [ebx + TCP_SOCKET.t_state], TCB_LISTEN
jz .dont_do_options
call TCP_do_options
.dont_do_options:
;-----------------------------------------------------------------------
; Time to do some header prediction (Original Principle by Van Jacobson)
; There are two common cases for an uni-directional data transfer.
;
; General rule: the packets has no control flags, is in-sequence,
; window width didnt change and we're not retransmitting.
;
; Second rules:
; - If the length is 0 and the ACK moved forward, we're the sender side of the transfer.
; In this case we'll free the ACK'ed data and notify higher levels that we have free space in buffer
;
; - If the length is not 0 and the ACK didn't move, we're the receiver side of the transfer.
; If the packets are in order (data queue is empty), add the data to the socket buffer and request a delayed ACK
cmp [TCP_SOCKET.t_state], TCB_ESTABLISHED
jnz .not_uni_xfer
test [TCP_segment.Flags], TH_SYN + TH_FIN + TH_RST + TH_URG
jnz .not_uni_xfer
test [TCP_segment.Flags], TH_ACK
jz .not_uni_xfer
mov eax, [edx + TCP_segment.SequenceNumber]
cmp eax, [ebx + TCP_SOCKET.RCV_NXT]
jne .not_uni_xfer
movzx eax, [edx + TCP_segment.Window] ;;;;;
cmp eax, [ebx + TCP_SOCKET.SND_WND]
jne .not_uni_xfer
mov eax, [ebx + TCP_SOCKET.SND_NXT]
cmp eax, [ebx + TCP_SOCKET.SND_MAX]
jne .not_uni_xfer
;-------------------------------------------------------------------------------
; If last ACK falls within this segment's sequence number, record the timestamp.
; TODO: check if it has a timestamp
;---------------------------------------
; check if we are sender in the uni-xfer
; If the following 4 conditions are all true, this segment is a pure ACK.
;
; - The segment contains no data (ti_len is 0).
movzx eax, [edx + TCP_segment.DataOffset]
and eax, 11110000b
shr eax, 2
sub ecx, eax
jnz .not_sender
; - The acknowledgment field in the segment (ti_ack) is greater than the largest unacknowledged sequence number (snd_una).
; 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.
mov eax, [edx + TCP_segment.AckNumber]
cmp eax, [ebx + TCP_SOCKET.SND_UNA]
jle .not_uni_xfer
; - The acknowledgment field in the segment (ti_ack) is less than or equal to the maximum sequence number sent (snd_max).
; mov eax, [edx + TCP_segment.Ack]
cmp eax, [ebx + TCP_SOCKET.SND_MAX]
jg .not_uni_xfer
; - The congestion window (snd_cwnd) is greater than or equal to the current send window (snd_wnd).
; 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.
mov eax, [ebx + TCP_SOCKET.SND_CWND]
cmp eax, [ebx + TCP_SOCKET.SND_WND]
jl .not_uni_xfer
DEBUGF 1,"Header prediction: we are sender\n"
;---------------------------------
; Packet is a pure ACK, process it
; Update RTT estimators
; Delete acknowledged bytes from send buffer
; Stop retransmit timer
mov [ebx + TCP_SOCKET.timer_ack], 0
; Awaken waiting processes
mov eax, ebx
call SOCKET_notify_owner
; Generate more output
call TCP_output
jmp .drop
;-------------------------------------------------
; maybe we are the receiver in the uni-xfer then..
.not_sender:
; The amount of data in the segment (ti_len) is greater than 0 (data count is in ecx)
; The acknowledgment field (ti_ack) equals the largest unacknowledged sequence number. This means no data is acknowledged by this segment.
mov eax, [edx + TCP_segment.AckNumber]
cmp eax, [ebx + TCP_SOCKET.SND_UNA]
jne .not_uni_xfer
; The reassembly list of out-of-order segments for the connection is empty (seg_next equals tp).
;;;;
jnz .not_uni_xfer
; There is room in the receive buffer for the data in the segment.
;;;;
jnz .not_uni_xfer
;-------------------------------------
; Complete processing of received data
DEBUGF 1,"header prediction: we are receiver\nreceiving %u bytes of data\n", ecx
; The next expected receive sequence number (rcv_nxt) is incremented by the number of bytes of data.
add [ebx + TCP_SOCKET.RCV_NXT], ecx
; Add the data to the socket buffer
mov eax, ebx
;;; mov...
call SOCKET_input
; The delayed-ACK flag is set and the input processing is complete.
jmp .drop
;----------------------------------------------------
; Header prediction failed, doing it the slow way..
.not_uni_xfer:
DEBUGF 1,"Header prediction failed\n"
;------------------------
; calculate header length ;;;;; we already calculated this before!
movzx eax, [edx + TCP_segment.DataOffset]
and eax, 0xf0
shr eax, 2
; Update edx to point to data..
add edx, eax
; ..and ecx to give data size
sub ecx, eax
;------------------------------
; Calculate receive window size
;;;;
;-------------------------
; TCP slow input procedure
DEBUGF 1,"TCP slow input procedure\n"
cmp [eax + TCP_SOCKET.t_state], TCB_LISTEN
je .LISTEN
cmp [eax + TCP_SOCKET.t_state], TCB_SYN_SENT
je .SYN_SENT
;--------------------------------------------
; Protection Against Wrapped Sequence Numbers
; First, check timestamp if present
;;;; TODO
; Then, check if at least some bytes of data are within window
;;;; TODO
jmp .trim_then_step6
align 4
.LISTEN:
DEBUGF 1,"TCP state: listen\n"
test [edx + TCP_segment.Flags], TH_RST
jnz .drop
test [edx + TCP_segment.Flags], TH_ACK
jnz .drop_with_reset
test [edx + TCP_segment.Flags], TH_SYN
jz .drop
; TODO: check if it's a broadcast or multicast, and drop if so
;;; 28.6
; create a new socket and fill in the nescessary variables
;; Exit if backlog queue is full
; mov ax, [ebx + TCP_SOCKET.backlog_cur]
; cmp ax, [ebx + TCP_SOCKET.backlog]
; jae .exit
; Allocate new socket
call SOCKET_alloc
;;; jz .fail
; Copy structure from current socket to new, (including lock!)
; We start at PID to reserve the socket num, and the 2 pointers at beginning of socket
lea esi, [edx + SOCKET.PID]
lea edi, [eax + SOCKET.PID]
mov ecx, (TCP_SOCKET.end - SOCKET.PID + 3)/4
rep movsd
;; Push pointer to new socket to queue
; movzx ecx, [ebx + TCP_SOCKET.backlog_cur]
; inc [ebx + TCP_SOCKET.backlog_cur]
; mov [ebx + TCP_SOCKET.end + ecx*4], eax
mov [eax + IP_SOCKET.RemoteIP], esi ; IP source address
mov cx, [edx + TCP_segment.SourcePort]
mov [eax + TCP_SOCKET.RemotePort], cx
mov ecx, [edx + TCP_segment.SequenceNumber]
mov [eax + TCP_SOCKET.IRS], ecx
mov ecx, [eax + TCP_SOCKET.ISS]
mov [eax + TCP_SOCKET.SND_NXT], ecx
jmp .trim_then_step6
align 4
.SYN_SENT:
DEBUGF 1,"TCP state: syn_sent\n"
test [edx + TCP_segment.Flags], TH_ACK
jz @f
mov eax, [edx + TCP_segment.AckNumber]
cmp eax, [ebx + TCP_SOCKET.ISS]
jle .drop_with_reset
mov eax, [edx + TCP_segment.AckNumber]
cmp eax, [ebx + TCP_SOCKET.SND_MAX]
jg .drop_with_reset
@@:
test [edx + TCP_segment.Flags], TH_RST
jz @f
test [edx + TCP_segment.Flags], TH_ACK
jz .drop
;tp = tcp_drop(tp, ECONNREFUSED)
jmp .drop
@@:
test [edx + TCP_segment.Flags], TH_SYN
jz .drop
; now, process received SYN in response to an active open
test [edx + TCP_segment.Flags], TH_ACK
jz @f
mov eax, [edx + TCP_segment.AckNumber]
mov [ebx + TCP_SOCKET.SND_UNA], eax
mov eax, [ebx + TCP_SOCKET.SND_UNA]
cmp eax, [ebx + TCP_SOCKET.SND_NXT]
jle @f
mov [ebx + TCP_SOCKET.SND_NXT], eax
mov [ebx + TCP_SOCKET.timer_keepalive], TCP_time_keep_interval
mov [ebx + TCP_SOCKET.timer_retransmission], 0
mov eax, [edx + TCP_segment.SequenceNumber]
mov [ebx + TCP_SOCKET.IRS], eax
; TODO: set socket state to connected
mov [ebx + TCP_SOCKET.t_state], TCB_ESTABLISHED
; TODO: check if we should scale the connection (567-572)
; TODO: update RTT estimators
@@:
; We have received a syn but no ACK, so we are having a simultaneous open..
mov [ebx + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
;-------------------------------------
; Common processing for receipt of SYN
.trimthenstep6:
inc [edx + TCP_segment.SequenceNumber]
cmp cx, [ebx + TCP_SOCKET.RCV_WND]
jle @f
movzx eax, cx
sub ax, [ebx + TCP_SOCKET.RCV_WND]
; TODO: 592
mov cx, [ebx + TCP_SOCKET.RCV_WND]
; TODO...
@@:
;;;;;
;;; jmp .step6
align 4
.trim_then_step6:
DEBUGF 1,"Trim, then step 6\n"
;----------------------------
; trim any data not in window
mov eax, [ebx + TCP_SOCKET.RCV_NXT]
sub eax, [edx + TCP_segment.SequenceNumber]
test eax, eax
jz .no_drop
test [edx + TCP_segment.Flags], TH_SYN
jz .no_drop
and [edx + TCP_segment.Flags], not (TH_SYN)
inc [edx + TCP_segment.SequenceNumber]
cmp [edx + TCP_segment.UrgentPointer], 1
jl @f
dec [edx + TCP_segment.UrgentPointer]
jmp .no_drop
@@:
and [edx + TCP_segment.Flags], not (TH_URG)
dec eax
.no_drop:
; eax holds number of bytes to drop
;----------------------------------
; Check for entire duplicate packet
cmp eax, ecx
jge .duplicate
;;; TODO: figure 28.30
;; inc [TCP_segments_rx]
;; add dword [TCP_bytes_rx], ecx
;; adc dword [TCP_bytes_rx+4], 0
;------------------------
; Check for duplicate FIN
test [edx + TCP_segment.Flags], TH_FIN
jz @f
inc ecx
cmp eax, ecx
dec ecx
jne @f
mov eax, ecx
and [edx + TCP_segment.Flags], not TH_FIN
;;; TODO: set ACKNOW flag
jmp .no_duplicate
@@:
; Handle the case when a bound socket connects to itself
; Allow packets with a SYN and an ACKto continue with the processing
;-------------------------------------
; Generate duplicate ACK if nescessary
; This code also handles simultaneous half-open or self-connects
test eax, eax
jnz .drop_after_ack
cmp [edx + TCP_segment.Flags], TH_ACK
jz .drop_after_ack
.duplicate:
;----------------------------------------
; Update statistics for duplicate packets
;;; TODO
;;; DROP the packet ??
.no_duplicate:
;-----------------------------------------------
; Remove duplicate data and update urgent offset
add [edx + TCP_segment.SequenceNumber], eax
;;; TODO
sub [edx + TCP_segment.UrgentPointer], ax
jg @f
and [edx + TCP_segment.Flags], not (TH_URG)
mov [edx + TCP_segment.UrgentPointer], 0
@@:
;--------------------------------------------------
; Handle data that arrives after process terminates
cmp [ebx + SOCKET.PID], 0
jge @f
cmp [ebx + TCP_SOCKET.t_state], TCB_CLOSE_WAIT
jle @f
test ecx, ecx
jz @f
;;; Close the socket
;;; update stats
jmp .drop_with_reset
@@:
;----------------------------------------
; Remove data beyond right edge of window
mov eax, [edx + TCP_segment.SequenceNumber]
add eax, ecx
sub eax, [ebx + TCP_SOCKET.RCV_NXT]
sub ax, [ebx + TCP_SOCKET.RCV_WND]
; eax now holds the number of bytes to drop
jle .no_excess_data
;;; TODO: update stats
cmp eax, ecx
jl .dont_drop_all
;;; TODO 700-736
.dont_drop_all:
.no_excess_data:
;-----------------
; Record timestamp
;;; TODO 737-746
;------------------
; Process RST flags
test [edx + TCP_segment.Flags], TH_RST
jz .rst_skip
mov eax, [ebx + TCP_SOCKET.t_state]
shl eax, 2
jmp dword [eax + .rst_sw_list]
.rst_sw_list:
dd .rst_skip ;TCB_CLOSED
dd .rst_skip ;TCB_LISTEN
dd .rst_skip ;TCB_SYN_SENT
dd .econnrefused ;TCB_SYN_RECEIVED
dd .econnreset ;TCB_ESTABLISHED
dd .econnreset ;TCB_CLOSE_WAIT
dd .econnreset ;TCB_FIN_WAIT_1
dd .rst_close ;TCB_CLOSING
dd .rst_close ;TCB_LAST_ACK
dd .econnreset ;TCB_FIN_WAIT_2
dd .rst_close ;TCB_TIMED_WAIT
.econnrefused:
;;; TODO: debug info
jmp .close
.econnreset:
;;; TODO: debug info
.close:
;;; update stats
.rst_close:
;;; Close the socket
jmp .drop
.rst_skip:
;--------------------------------------
; handle SYN-full and ACK-less segments
test [edx + TCP_segment.Flags], TH_SYN
jz @f
;;; tcp_drop ( ECONNRESET)
jmp .drop_with_reset
test [edx + TCP_segment.Flags], TH_ACK
jz .drop
;----------------
; Process the ACK
cmp [ebx + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
jg .ack_dup
jl .ack_nodup
;;;;;
.ack_dup:
;;;;
.ack_nodup:
;;;; 887
;-------------------------------------------------
; If the congestion window was inflated to account
; for the other side's cached packets, retrace it
;;;; 888 - 902
;------------------------------------------
; RTT measurements and retransmission timer
;;;;; 903 - 926
mov [ebx + TCP_SOCKET.timer_retransmission], 0
mov eax, [ebx + TCP_SOCKET.SND_MAX]
cmp eax, [edx + TCP_segment.AckNumber]
je .all_outstanding
mov [ebx + TCP_SOCKET.timer_retransmission], 120 ;;;; TODO: correct this value
.all_outstanding:
;-------------------------------------------
; Open congestion window in response to ACKs
;;;;
;------------------------------------------
; Remove acknowledged data from send buffer
;;;; 943 - 956
;---------------------------------------
; Wake up process waiting on send buffer
;;;;;
mov eax, [ebx + TCP_SOCKET.t_state]
shl eax, 2
jmp dword [eax + .ACK_sw_list]
.ACK_sw_list:
dd .step6 ;TCB_CLOSED
dd .step6 ;TCB_LISTEN
dd .step6 ;TCB_SYN_SENT
dd .step6 ;TCB_SYN_RECEIVED
dd .step6 ;TCB_ESTABLISHED
dd .step6 ;TCB_CLOSE_WAIT
dd ._963 ;TCB_FIN_WAIT_1
dd ._958 ;TCB_CLOSING
dd ._999 ;TCB_LAST_ACK
dd .step6 ;TCB_FIN_WAIT_2
dd ._1010 ;TCB_TIMED_WAIT
._963:
jmp .step6
._958:
jmp .step6
._999:
jmp .step6
._1010:
jmp .step6
align 4
.step6:
DEBUGF 1,"step 6\n"
;--------------------------
; update window information
test [edx + TCP_segment.Flags], TH_ACK
jz .no_window_update
mov eax, [ebx + TCP_SOCKET.SND_WL1]
cmp eax, [edx + TCP_segment.SequenceNumber]
;;;; 1021
;----------------------------------
; Keep track of pure window updates
test ecx, ecx
jz @f
mov eax, [ebx + TCP_SOCKET.SND_WL2]
cmp eax, [edx + TCP_segment.AckNumber]
jne @f
;; mov eax, tiwin
cmp eax, [ebx + TCP_SOCKET.SND_WND]
jle @f
;;; update stats
@@:
;; mov eax, incoming window
cmp eax, [ebx + TCP_SOCKET.max_sndwnd]
jle @f
mov [ebx + TCP_SOCKET.max_sndwnd], eax
@@:
mov [ebx + TCP_SOCKET.SND_WND], eax
mov eax, [edx + TCP_segment.SequenceNumber]
mov [ebx + TCP_SOCKET.SND_WL1], eax
mov eax, [edx + TCP_segment.AckNumber]
mov [ebx + TCP_SOCKET.SND_WL2], eax
;;; needoutput = 1
.no_window_update:
;-----------------
; process URG flag
test [edx + TCP_segment.Flags], TH_URG
jz .not_urgent
cmp [edx + TCP_segment.UrgentPointer], 0
jz .not_urgent
cmp [ebx + TCP_SOCKET.t_state], TCB_TIMED_WAIT
je .not_urgent
; Ignore bogus urgent offsets
;;; 1040-1050
movzx eax, [edx + TCP_segment.UrgentPointer]
add eax, [ebx + SOCKET.SO_RCV.SB_CC]
cmp eax, SOCKET_MAXDATA
jle .not_urgent
mov [edx + TCP_segment.UrgentPointer], 0
and [edx + TCP_segment.Flags], not (TH_URG)
jmp .do_data
.not_urgent:
;--------------------------------------
; processing of received urgent pointer
;;; 1051-1093
align 4
.do_data:
DEBUGF 1,"Do data:\n"
; process the data in the segment
test [edx + TCP_segment.Flags], TH_FIN
jz .process_fin
test [ebx + TCP_SOCKET.t_state], TCB_FIN_WAIT_1 ;;;;;
jge .dont_do_data
DEBUGF 1,"Processing data in segment\n"
;;; NOW, process the data
jmp .final_processing
.dont_do_data:
;---------------
; FIN processing
.process_fin:
DEBUGF 1,"Processing FIN\n"
mov eax, [ebx + TCP_SOCKET.t_state]
shl eax, 2
jmp dword [eax + .FIN_sw_list]
.FIN_sw_list:
dd .no_fin ;TCB_CLOSED
dd .no_fin ;TCB_LISTEN
dd .no_fin ;TCB_SYN_SENT
dd ._1131 ;TCB_SYN_RECEIVED
dd ._1131 ;TCB_ESTABLISHED
dd .no_fin ;TCB_CLOSE_WAIT
dd ._1139 ;TCB_FIN_WAIT_1
dd .no_fin ;TCB_CLOSING
dd .no_fin ;TCB_LAST_ACK
dd ._1147 ;TCB_FIN_WAIT_2
dd ._1156 ;TCB_TIMED_WAIT
._1131:
._1139:
._1147:
._1156:
.no_fin:
;-----------------
; Final processing
.final_processing:
DEBUGF 1,"Final processing\n"
;;; if debug enabled, output packet
;test ;;;needoutput = 1
;jnz .outputnow
test [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
jz .ret
.outputnow:
call TCP_output
.ret:
mov [ebx + SOCKET.lock], 0
call kernel_free
ret 4
;------------------------------------------
; Generate an ACK, droping incoming segment
align 4
.drop_after_ack:
DEBUGF 1,"Drop after ACK\n"
test [edx + TCP_segment.Flags], TH_RST
jnz .drop
and [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
call TCP_output
mov [ebx + SOCKET.lock], 0
call kernel_free
ret 4
;-------------------------------------------
; Generate an RST, dropping incoming segment
align 4
.drop_with_reset:
DEBUGF 1,"Drop with reset\n"
test [edx + TCP_segment.Flags], TH_RST
jnz .drop
;;; if its a multicast/broadcast, also drop
test [edx + TCP_segment.Flags], TH_ACK
jnz .respond_ack
test [edx + TCP_segment.Flags], TH_SYN
jnz .respond_syn
mov [ebx + SOCKET.lock], 0
call kernel_free
ret 4
.respond_ack:
;;;;
call TCP_respond
jmp .destroy_new_socket
.respond_syn:
;;;;
call TCP_respond
jmp .destroy_new_socket
;-----
; Drop
align 4
.drop:
DEBUGF 1,"Dropping packet\n"
;;;; If debugging options are enabled, output the packet somwhere
.destroy_new_socket:
;;;; kill the newly created socket
mov [ebx + SOCKET.lock], 0
call kernel_free
ret 4
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;---------------------
;
; TCP_do_options
;
;-------------------
align 4
TCP_do_options:
DEBUGF 1,"TCP_do_options\n"
push eax
sub eax, 20
jz .no_options
lea esi, [edx + TCP_segment.Data]
;-------------------------------------------
; Begin the loop by checking for EOL and NOP
.loop:
cmp byte [esi], TCP_OPT_EOL ; end of option list?
jz .no_options
cmp byte [esi], TCP_OPT_NOP ; nop ?
;;; cmove edi, 1 ; if so, set option size to 1
jz .continue ; and continue scanning
;------------------
; We have an option
movzx edi, byte [esi + 1] ; get the length of this option in edi
;--------------------------------------
; Check for Maximum segment size option
cmp byte [esi], TCP_OPT_MAXSEG
jne .no_maxseg
cmp edi, 4 ; option length
jne .continue
test [edx + TCP_segment.Flags], TH_SYN
jz .continue
; Now parse the option...
jmp .continue
.no_maxseg:
;------------------------
; Check for Window option
cmp byte [esi], TCP_OPT_WINDOW
jne .no_window
cmp edi, 3 ; option length
jne .continue
test [edx + TCP_segment.Flags], TH_SYN
jz .continue
; ...
jmp .continue
.no_window:
;---------------------------
; Check for Timestamp option
cmp byte [esi], TCP_OPT_TIMESTAMP
jne .no_timestamp
cmp edi, 10 ; option length
jne .continue
; ...
jmp .continue
.no_timestamp:
;----------------------------------
; Future options may be placed here
;------------------------------
; Continue scanning for options
.continue:
add esi, edi
sub eax, edi
jg .loop
.no_options:
pop eax
ret
;---------------------------
;
; TCP_pull_out_of_band
;
; IN: eax =
; ebx = socket ptr
; edx = tcp packet ptr
;
; OUT: /
;
;---------------------------
align 4
TCP_pull_out_of_band:
DEBUGF 1,"TCP_pull_out_of_band\n"
;;;; 1282-1305
ret
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;-----------------------------------------------------------------
;
; TCP_output
;
; IN: eax = socket pointer
;; esi = ptr to data
;; ecx = number of data bytes
;
; OUT: /
;
;-----------------------------------------------------------------
align 4
TCP_output:
DEBUGF 1,"TCP_output, socket: %x\n", eax
; We'll detect the length of the data to be transmitted, and flags to be used
; If there is some data, or any critical controls to send (SYN / RST), then transmit
; Otherwise, investigate further
mov ebx, [eax + TCP_SOCKET.SND_MAX]
cmp ebx, [eax + TCP_SOCKET.SND_UNA]
jne .not_idle
mov ebx, [eax + TCP_SOCKET.t_idle]
cmp ebx, [eax + TCP_SOCKET.t_rxtcur]
jle .not_idle
; We have been idle for a while and no ACKS are expected to clock out any data we send..
; Slow start to get ack "clock" running again.
mov ebx, [eax + TCP_SOCKET.t_maxseg]
mov [eax + TCP_SOCKET.SND_CWND], ebx
.not_idle:
.again:
mov ebx, [eax + TCP_SOCKET.SND_NXT] ; calculate offset
sub ebx, [eax + TCP_SOCKET.SND_UNA] ;
mov ecx, [eax + TCP_SOCKET.SND_WND] ; determine window
cmp ecx, [eax + TCP_SOCKET.SND_CWND] ;
jl @f ;
mov ecx, [eax + TCP_SOCKET.SND_CWND] ;
@@: ;
call TCP_outflags
; If in persist timeout with window of 0, send 1 byte.
; Otherwise, if window is small but nonzero, and timer expired,
; we will send what we can and go to transmit state
test [eax + TCP_SOCKET.t_force], -1
jz .no_persist_timeout
test ecx, ecx
jnz .no_zero_window
cmp ebx, [eax + SOCKET.SO_SND.SB_CC]
jge @f
and dl, not (TH_FIN) ; clear the FIN flag ??? how can it be set before?
@@:
inc ecx
jmp .no_persist_timeout
.no_zero_window:
;;; mov [eax + TCP_SOCKET.t_timer....TCPT_PERSIST], 0
mov [eax + TCP_SOCKET.t_rxtshift], 0
.no_persist_timeout:
;;;106
mov esi, [eax + SOCKET.SO_SND.SB_CC]
cmp esi, ecx
jl @f
mov esi, ecx
@@:
sub esi, ebx
cmp esi, -1
jne .not_minus_one
; If FIN has been set, but not ACKed, and we havent been called to retransmit,
; len (esi) will be -1
; Otherwise, window shrank after we sent into it.
; If window shrank to 0, cancel pending retransmit and pull SND_NXT back to (closed) window
; We will enter persist state below.
; If window didn't close completely, just wait for an ACK
xor esi, esi
test ecx, ecx
jnz @f
;;; mov [eax + TCP_SOCKET.t_timer..TCPT_REXMT], 0
push [eax + TCP_SOCKET.SND_UNA]
pop [eax + TCP_SOCKET.SND_NXT]
@@:
.not_minus_one:
;;; 124
cmp esi, [eax + TCP_SOCKET.t_maxseg]
jle @f
mov esi, [eax + TCP_SOCKET.t_maxseg]
;sendalot = 1
@@:
;;; 128
mov edi, [eax + TCP_SOCKET.SND_NXT]
add edi, esi ; len
sub edi, [eax + TCP_SOCKET.SND_UNA]
add edi, [eax + SOCKET.SO_SND.SB_CC]
cmp edi, 0
jle @f
and dl, not (TH_FIN) ; clear the FIN flag
@@:
;;;; 130 TODO: set window (ecx) to space in send buffer
;------------------------------
; Sender silly window avoidance
test esi, esi
jz .zero_length
cmp esi, [eax + TCP_SOCKET.t_maxseg]
je .send
;;; TODO: 144-145
test [eax + TCP_SOCKET.t_force], -1
jnz .send
;;; TODO: 149..152
.zero_length:
;----------------------------------------
; Check if a window update should be sent
cmp ecx, 0 ; window
jle .no_window
;;; TODO 154-172
.no_window:
;--------------------------
; Should a segment be sent?
test [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
jnz .send
test dl, TH_SYN + TH_RST
jnz .send
mov eax, [ebx + TCP_SOCKET.SND_UP]
cmp eax, [ebx + TCP_SOCKET.SND_UNA]
jg .send
test dl, TH_FIN
jz .enter_persist
test [ebx + TCP_SOCKET.t_flags], TF_SENTFIN
jnz .send
mov eax, [ebx + TCP_SOCKET.SND_NXT]
cmp eax, [ebx + TCP_SOCKET.SND_UNA]
je .send
;--------------------
; Enter persist state
.enter_persist:
DEBUGF 1,"Entering persist state\n"
;--------------------------------------
; No reason to send a segment, just ret
DEBUGF 1,"No reason to send a segment\n"
ret
;-----------------------------------------------
;
; Send a segment
;
; ebx = socket pointer
; dl = flags
;
;-----------------------------------------------
.send:
DEBUGF 1,"Preparing to send a segment\n"
xor edi, edi ; edi will contain the number of header option bytes
;------------------------------------
; Send options with first SYN segment
test dl, TH_SYN
jz .no_options
mov eax, [ebx + TCP_SOCKET.ISS]
mov [ebx + TCP_SOCKET.SND_NXT], eax
test [ebx + TCP_SOCKET.t_flags], TF_NOOPT
jnz .no_options
mov eax, TCP_OPT_MAXSEG shl 24 + 4 shl 16
mov ax, 1280 ;;;;;;
bswap eax
push eax
mov di, 4
test [ebx + TCP_SOCKET.t_flags], TF_REQ_SCALE
jz .no_syn
test dl, TH_ACK
jnz .scale_opt
test [ebx + TCP_SOCKET.t_flags], TF_RCVD_SCALE
jz .no_syn
.scale_opt:
mov eax, TCP_OPT_WINDOW shl 24 + 4 shl 16 + TCP_OPT_NOP
mov ah, byte [ebx + TCP_SOCKET.request_r_scale]
bswap eax
push eax
add di, 4
.no_syn:
;------------------------------------
; Make the timestamp option if needed
test [ebx + TCP_SOCKET.t_flags], TF_REQ_TSTMP
jz .no_timestamp
test dl, TH_RST
jnz .no_timestamp
test dl, TH_ACK
jz .timestamp
test [ebx + TCP_SOCKET.t_flags], TF_RCVD_TSTMP
jz .no_timestamp
.timestamp:
DEBUGF 1,"Creating a timestamp\n"
push dword (TCP_OPT_TIMESTAMP shl 8 + 10 + TCP_OPT_NOP shl 16 + TCP_OPT_NOP shl 24)
pushw 0
mov eax, [timer_ticks]
bswap eax
push eax
add di, 10
.no_timestamp:
;; TODO: check if we dont exceed the max segment size
.no_options:
add edi, TCP_segment.Data
;-----------------------------------
; Check if we have some data to send
;;; mov ecx, [huppeldepup]
test ecx, ecx
jz .no_data
;;; 278-316
jmp .header
.no_data:
;;; 317-338
;----------
push di dx ebx
add ecx, edi ; total TCP segment size
mov eax, [ebx + IP_SOCKET.RemoteIP]
mov ebx, [ebx + IP_SOCKET.LocalIP]
mov di , IP_PROTO_TCP
call IPv4_create_packet
;;;; jz .fail
push edx eax
call [ebx + NET_DEVICE.transmit]
ret
;----------------
;-------------------------------
; Now, create the 20-byte header
.header:
;-----------------------
; Fill in the TCP header
pop esi
push [esi + TCP_SOCKET.SND_NXT]
rol word [esp], 8
rol dword [esp], 16
pop [edi + TCP_segment.SequenceNumber]
push [esi + TCP_SOCKET.RCV_NXT]
rol word [esp], 8
rol dword [esp], 16
pop [edi + TCP_segment.AckNumber]
push [esi + TCP_SOCKET.LocalPort]
rol word [esp], 8
pop [edi + TCP_segment.SourcePort]
push [esi + TCP_SOCKET.RemotePort]
rol word [esp], 8
pop [edi + TCP_segment.DestinationPort]
mov [edi + TCP_segment.Window], 0x0005
; 1280 bytes
mov [edi + TCP_segment.UrgentPointer], 0
mov [edi + TCP_segment.DataOffset], 0x50
mov [edi + TCP_segment.Flags], cl
mov [edi + TCP_segment.Checksum], 0
;-----
;--------------
; Copy the data
pop esi
push edi
add edi, TCP_segment.Data ;;
sub ecx, TCP_segment.Data ;;;
shr ecx, 1
jnc .nb
movsb
.nb:
shr ecx, 1
jnc .nw
movsw
.nw:
test ecx, ecx
jz .nd
rep movsd
.nd:
pop edi
;--------------------
; Create the checksum
push [ebx + IP_SOCKET.LocalIP]
push [ebx + IP_SOCKET.RemoteIP]
call TCP_checksum
;----------------
; Send the packet
;;;;;
DEBUGF 1,"Sending TCP Packet to device %x\n", ebx
call [ebx + NET_DEVICE.transmit]
ret
;-------------------------
;
; TCP_outflags
;
; IN: eax = socket ptr
;
; OUT: edx = flags
;
;-------------------------
align 4
TCP_outflags:
mov edx, [eax + TCP_SOCKET.t_state]
movzx edx, byte [edx + .flaglist]
DEBUGF 1,"TCP_outflags, socket: %x, flags: %x\n", eax, dl
ret
.flaglist:
db TH_RST + TH_ACK ; TCB_CLOSED
db 0 ; TCB_LISTEN
db TH_SYN ; TCB_SYN_SENT
db TH_SYN + TH_ACK ; TCB_SYN_RECEIVED
db TH_ACK ; TCB_ESTABLISHED
db TH_ACK ; TCB_CLOSE_WAIT
db TH_SYN + TH_ACK ; TCB_FIN_WAIT_1
db TH_SYN + TH_ACK ; TCB_CLOSING
db TH_SYN + TH_ACK ; TCB_LAST_ACK
db TH_ACK ; TCB_FIN_WAIT_2
db TH_ACK ; TCB_TIMED_WAIT
;-------------------------
;
; TCP_drop
;
; IN: eax = socket ptr
;
; OUT: /
;
;-------------------------
align 4
TCP_drop:
DEBUGF 1,"TCP_drop\n"
; cmp [eax + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
; jl .no_syn_received
mov [eax + TCP_SOCKET.t_state], TCB_CLOSED
call TCP_output
; .no_syn_received:
ret
;---------------------------------------
;
; TCP_ack
;
; The easy way to send an ACK/RST/keepalive segment
;
; IN: eax = socket ptr
; -or-
; edx = packet ptr (eax must be 0)
; cl = flags
;
; OUT: /
;
;---------------------------------------
align 4
TCP_respond:
DEBUGF 1,"TCP_respond\n"
;---------------------
; Create the IP packet
push cx eax edx
mov ebx, [eax + IP_SOCKET.LocalIP]
mov eax, [eax + IP_SOCKET.RemoteIP]
mov ecx, TCP_segment.Data
mov di , IP_PROTO_TCP
call IPv4_create_packet
test edi, edi
jz .error
;---------------------------
; Now fill in the TCP header
pop ecx
pop esi
test esi, esi
; jz
push edx eax
push dword .checksum
je .use_segment
jmp .use_socket
;---------------------
; Fill in the checksum
.checksum:
push [esi + IP_SOCKET.LocalIP]
push [esi + IP_SOCKET.RemoteIP]
lea esi, [edi - 20]
xor ecx, ecx
call TCP_checksum
;--------------------
; And send the segment
call [ebx + NET_DEVICE.transmit]
ret
.error:
DEBUGF 1,"TCP_ack failed\n"
add esp, 4
ret
;---------------------------------------------------
; Fill in the TCP header by using a received segment
.use_segment:
mov ax, [esi + TCP_segment.DestinationPort]
rol ax, 8
stosw
mov ax, [esi + TCP_segment.SourcePort]
rol ax, 8
stosw
mov eax, [esi + TCP_segment.AckNumber]
bswap eax
stosd
xor eax, eax
stosd
mov al, 0x50 ; Dataoffset: 20 bytes
stosb
mov al, cl
stosb
mov ax, 1280
rol ax, 8
stosw ; window
xor eax, eax
stosd ; checksum + urgentpointer
ret
;-----------------------------------------------
; Fill in the TCP header by using the socket ptr
.use_socket:
mov ax, [esi + TCP_SOCKET.LocalPort]
rol ax, 8
stosw
mov ax, [esi + TCP_SOCKET.RemotePort]
rol ax, 8
stosw
mov eax, [esi + TCP_SOCKET.SND_NXT]
bswap eax
stosd
mov eax, [esi + TCP_SOCKET.RCV_NXT]
bswap eax
stosd
mov al, 0x50 ; Dataoffset: 20 bytes
stosb
mov al, cl
stosb
mov ax, [esi + TCP_SOCKET.RCV_WND]
rol ax, 8
stosw ; window
xor eax, eax
stosd ; checksum + urgentpointer
ret
;-----------------------------------------------------------------
;
; TCP_checksum
;
; This is the fast procedure to create or check a UDP header
; - To create a new checksum, the checksum field must be set to 0 before computation
; - To check an existing checksum, leave the checksum as is,
; and it will be 0 after this procedure, if it was correct
;
; IN: push source ip
; push dest ip
;
; esi = packet ptr
;
; OUT: checksum is filled in in packet! (but also in dx)
;
;-----------------------------------------------------------------
align 4
TCP_checksum:
;-------------
; Pseudoheader
; protocol type
mov edx, IP_PROTO_TCP ; NO shl 8 here ! (it took me ages to figure this one out)
; source address
add dl, [esp+1+4]
adc dh, [esp+0+4]
adc dl, [esp+3+4]
adc dh, [esp+2+4]
; destination address
adc dl, [esp+1+8]
adc dh, [esp+0+8]
adc dl, [esp+3+8]
adc dh, [esp+2+8]
; size
adc dl, cl
adc dh, ch
;---------------------
; Real header and data
push esi
call checksum_1
call checksum_2
pop esi
neg [esi+UDP_Packet.Checksum] ; zero will stay zero so we just get the checksum
add [esi+UDP_Packet.Checksum], dx ; , else we will get (new checksum - old checksum) in the end, wich should be 0 :)
ret 8 ; Remove the IPs from stack
;---------------------------------------------------------------------------
;
; TCP_API
;
; This function is called by system function 75
;
; IN: subfunction number in bl
; device number in bh
; ecx, edx, .. depends on subfunction
;
; OUT:
;
;---------------------------------------------------------------------------
align 4
TCP_API:
movzx eax, bh
shl eax, 2
test bl, bl
jz .packets_tx ; 0
dec bl
jz .packets_rx ; 1
.error:
mov eax, -1
ret
.packets_tx:
add eax, TCP_segments_tx
mov eax, [eax]
ret
.packets_rx:
add eax, TCP_segments_rx
mov eax, [eax]
ret