$Revision: 431 $
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; Copyright (C) KolibriOS team 2004-2007. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License ;;
;; ;;
;; TCP.INC ;;
;; ;;
;; TCP Processes for Menuet OS TCP/IP stack ;;
;; ;;
;; Version 0.6 4th July 2004 ;;
;; ;;
;; Copyright 2002 Mike Hibbett, mikeh@oceanfree.net ;;
;; ;;
;; See file COPYING for details ;;
;; v0.6 : Added reset handling in the established state ;;
;; Added a timer per socket to allow delays when ;;
;; rx window gets below 1KB ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; TCP TCB states
TCB_LISTEN equ 1
TCB_SYN_SENT equ 2
TCB_SYN_RECEIVED equ 3
TCB_ESTABLISHED equ 4
TCB_FIN_WAIT_1 equ 5
TCB_FIN_WAIT_2 equ 6
TCB_CLOSE_WAIT equ 7
TCB_CLOSING equ 8
TCB_LAST_ACK equ 9
TCB_TIME_WAIT equ 10
TCB_CLOSED equ 11
TWOMSL equ 10 ; # of secs to wait before closing socket
TCP_RETRIES equ 5 ; Number of times to resend a packet
TCP_TIMEOUT equ 10 ; resend if not replied to in x hs
;*******************************************************************
; Interface
;
; tcp_tx_handler Handles the TCP transmit queue
; tcp_rx The protocol handler for received data
; buildTCPPacket fills in the packet headers and data
; tcpStateMachine Main state machine for received TCP packets
; tcp_tcb_handler 1s timer, to erase tcb's in TIME_WAIT state
;
;*******************************************************************
; TCP Payload ( Data field in IP datagram )
;
; 0 1 2 3
; 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;20 | Source Port | Destination Port |
; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;24 | Sequence Number |
; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;28 | Acknowledgment Number |
; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;32 | Data | |U|A|P|R|S|F| |
; | Offset| Reserved |R|C|S|S|Y|I| Window |
; | | |G|K|H|T|N|N| |
; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;36 | Checksum | Urgent Pointer |
; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;40 | Options | Padding |
; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
; | data
struc TCP_PACKET
{ .SourcePort dw ? ;+00
.DestinationPort dw ? ;+02
.SequenceNumber dd ? ;+04
.AckNumber dd ? ;+08
.DataOffset db ? ;+12 - DataOffset[0-3 bits] and Reserved[4-7]
.Flags db ? ;+13 - Reserved[0-1 bits]|URG|ACK|PSH|RST|SYN|FIN
.Window dw ? ;+14
.Checksum dw ? ;+16
.UrgentPointer dw ? ;+18
.Options rb 3 ;+20
.Padding db ? ;+23
.Data db ? ;+24
}
virtual at 0
TCP_PACKET TCP_PACKET
end virtual
;***************************************************************************
; Function
; tcp_tcb_handler
;
; Description
; Handles sockets in the timewait state, closing them
; when the TCB timer expires
;
;***************************************************************************
tcp_tcb_handler:
; scan through all the sockets, decrementing active timers
mov eax, SOCKETBUFFSIZE * NUM_SOCKETS
mov ecx, NUM_SOCKETS
tth1:
sub eax, SOCKETBUFFSIZE
cmp [eax + sockets + 32], dword 0
jne tth2
tth1a:
cmp [eax + sockets + 72], dword 0
jne tth4
loop tth1
ret
tth2:
; decrement it, delete socket if TCB timer = 0 & socket in timewait state
pusha
dec dword [eax + sockets + 32]
cmp [eax + sockets + 32], dword 0
jne tth3
cmp [eax + sockets + 28], dword TCB_TIME_WAIT
jne tth3
; OK, delete socket
mov edi, eax
add edi, sockets
xor eax, eax
mov ecx, SOCKETHEADERSIZE
cld
rep stosb
tth3:
popa
jmp tth1a
loop tth1
ret
; TODO - prove it works!
tth4:
dec dword [eax + sockets + 72]
loop tth1
ret
tth_exit:
ret
;***************************************************************************
; Function
; tcp_tx_handler
;
; Description
; Handles queued TCP data
; This is a kernel function, called by stack_handler
;
;***************************************************************************
tcp_tx_handler:
; decrement all resend buffers timers. If they
; expire, queue them for sending, and restart the timer.
; If the retries counter reach 0, delete the entry
mov esi, resendQ
mov ecx, 0
tth001:
cmp ecx, NUMRESENDENTRIES
je tth003 ; None left
cmp [esi], byte 0xFF
jne tth002 ; found one
inc ecx
add esi, 4
jmp tth001
tth002:
; we have one. decrement it's timer by 1
dec word [esi+2]
mov ax, [esi+2]
cmp ax, 0
je tth002a
inc ecx
add esi, 4
jmp tth001 ; Timer not zero, so move on
tth002a:
mov bl, 0xff
; restart timer, and decrement retries
; After the first resend, back of on next, by a factor of 5
mov [esi+2], word TCP_TIMEOUT * 5
dec byte [esi+1]
mov al, [esi+1]
cmp al, 0
jne tth004
; retries now 0, so delete from queue
xchg [esi], bl
tth004:
; resend packet
pusha
mov eax, EMPTY_QUEUE
call dequeue
cmp ax, NO_BUFFER
jne tth004z
; TODO - try again in 10ms.
cmp bl, 0xff
jne tth004za
mov [esi], bl
tth004za:
; Mark it to expire in 10ms - 1 tick
mov [esi+1], byte 1
mov [esi+2], word 1
jmp tth005
tth004z:
; we have a buffer # in ax
push eax
push ecx
mov ecx, IPBUFFSIZE
mul ecx
add eax, IPbuffs
; we have the buffer address in eax
mov edi, eax
pop ecx
; get resend data address
inc ecx
; Now get buffer location, and copy buffer across. argh! more copying,,
mov esi, resendBuffer - IPBUFFSIZE
tth004a:
add esi, IPBUFFSIZE
loop tth004a
; we have resend buffer location in esi
mov ecx, IPBUFFSIZE
; copy data across
cld
rep movsb
; queue packet
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [ edi + 16 ]
cmp edx, ecx
jne tth004b
mov eax, IPIN_QUEUE
tth004b:
pop ebx
call queue
tth005:
popa
inc ecx
add esi, 4
jmp tth001
tth003:
ret
;***************************************************************************
; Function
; tcp_rx
;
; Description
; TCP protocol handler
; This is a kernel function, called by ip_rx
; IP buffer address given in edx
; IP buffer number in eax
; Free up (or re-use) IP buffer when finished
;
;***************************************************************************
tcp_rx:
; The process is as follows.
; Look for a socket with matching remote IP, remote port, local port
; if not found, then
; look for remote IP + local port match ( where sockets remote port = 0)
; if not found, then
; look for a socket where local socket port == IP packets remote port
; where sockets remote port, remote IP = 0
; discard if not found
; Call sockets tcbStateMachine, with pointer to packet.
; the state machine will not delete the packet, so do that here.
push eax
; Look for a socket where
; IP Packet TCP Destination Port = local Port
; IP Packet SA = Remote IP
; IP Packet TCP Source Port = remote Port
mov eax, SOCKETBUFFSIZE * NUM_SOCKETS
mov ecx, NUM_SOCKETS
ss1:
sub eax, SOCKETBUFFSIZE
movzx ebx, word [edx + 22] ; get the dest. port from the TCP hdr
cmp [eax + sockets + 12], bx ; compare with socket's local port
jnz nxttst1 ; different - try next socket
movzx ebx, word [edx + 20] ; get the source port from the TCP hdr
cmp [eax + sockets + 20], bx ; compare with socket's remote port
jnz nxttst1 ; different - try next socket
mov ebx, [edx + 12] ; get the source IP Addr from the IP hdr
cmp [eax + sockets + 16], ebx ; compare with socket's remote IP
jnz nxttst1 ; different - try next socket
; We have a complete match - use this socket
jmp tcprx_001
nxttst1:
loop ss1 ; Return back if no match
; If we got here, there was no match
; Look for a socket where
; IP Packet TCP Destination Port = local Port
; IP Packet SA = Remote IP
; socket remote Port = 0
mov eax, SOCKETBUFFSIZE * NUM_SOCKETS
mov ecx, NUM_SOCKETS
ss2:
sub eax, SOCKETBUFFSIZE
movzx ebx, word [edx + 22] ; get the dest. port from the TCP hdr
cmp [eax + sockets + 12], bx ; compare with socket's local port
jnz nxttst2 ; different - try next socket
mov ebx, [edx + 12] ; get the source IP Addr from the IP hdr
cmp [eax + sockets + 16], ebx ; compare with socket's remote IP
jnz nxttst2 ; different - try next socket
mov ebx, 0
cmp [eax + sockets + 20], bx ; only match a remote socket of 0
jnz nxttst2 ; different - try next socket
; We have a complete match - use this socket
jmp tcprx_001
nxttst2:
loop ss2 ; Return back if no match
; If we got here, there was no match
; Look for a socket where
; IP Packet TCP Destination Port = local Port
; socket Remote IP = 0
; socket remote Port = 0
mov eax, SOCKETBUFFSIZE * NUM_SOCKETS
mov ecx, NUM_SOCKETS
ss3:
sub eax, SOCKETBUFFSIZE
movzx ebx, word [edx + 22] ; get destination port from the TCP hdr
cmp [eax + sockets + 12], bx ; compare with socket's local port
jnz nxttst3 ; different - try next socket
mov ebx, 0
cmp [eax + sockets + 20], bx ; only match a remote socket of 0
jnz nxttst3 ; different - try next socket
mov ebx, 0
cmp [eax + sockets + 16], ebx ; only match a socket remote IP of 0
jnz nxttst3 ; different - try next socket
; We have a complete match - use this socket
jmp tcprx_001
nxttst3:
loop ss3 ; Return back if no match
; If we got here, we need to reject the packet
inc dword [dumped_rx_count]
jmp tcprx_exit
tcprx_001:
; We have a valid socket/TCB, so call the TCB State Machine for that skt.
; socket is pointed to by [eax + sockets]
; IP packet is pointed to by [edx]
; IP buffer number is on stack ( it will be popped at the end)
call tcpStateMachine
tcprx_exit:
pop eax
call freeBuff
ret
;***************************************************************************
; Function
; buildTCPPacket
;
; Description
; builds an IP Packet with TCP data fully populated for transmission
; You may destroy any and all registers
; TCP control flags specified in bl
; This TCB is in [sktAddr]
; User data pointed to by esi
; Data length in ecx
; Transmit buffer number in eax
;
;***************************************************************************
buildTCPPacket:
push ecx ; Save data length
; convert buffer pointer eax to the absolute address
mov ecx, IPBUFFSIZE
mul ecx
add eax, IPbuffs
mov edx, eax
mov [edx + 33], bl ; TCP flags
mov ebx, [sktAddr]
; So, ebx holds the socket ptr, edx holds the IPbuffer ptr
; Fill in the IP header ( some data is in the socket descriptor)
mov eax, [ebx + 8]
mov [edx + 12], eax ; source IP
mov eax, [ebx + 16]
mov [edx + 16], eax ; Destination IP
mov al, 0x45
mov [edx], al ; Version, IHL
xor al, al
mov [edx + 1], al ; Type of service
pop eax ; Get the TCP data length
push eax
add eax, 20 + 20 ; add IP header and TCP header lengths
mov [edx + 2], ah
mov [edx + 3], al
xor al, al
mov [edx + 4], al
mov [edx + 5], al
mov al, 0x40
mov [edx + 6], al
xor al, al
mov [edx + 7], al
mov al, 0x20
mov [edx + 8], al
mov al, 6 ; TCP protocol
mov [edx + 9], al
; Checksum left unfilled
xor ax, ax
mov [edx + 10], ax
; Fill in the TCP header ( some data is in the socket descriptor)
mov ax, [ebx + 12]
mov [edx + 20], ax ; Local Port
mov ax, [ebx + 20]
mov [edx + 20 + 2], ax ; desitination Port
; Checksum left unfilled
xor ax, ax
mov [edx + 20 + 16], ax
; sequence number
mov eax, [ebx + 48]
mov [edx + 20 + 4], eax
; ack number
mov eax, [ebx + 56]
mov [edx + 20 + 8], eax
; window ( 0x2000 is default ).I could accept 4KB, fa0, ( skt buffer size)
; 768 bytes seems better
mov ax, 0x0003
mov [edx + 20 + 14], ax
; Urgent pointer (0)
mov ax, 0
mov [edx + 20 + 18], ax
; data offset ( 0x50 )
mov al, 0x50
mov [edx + 20 + 12], al
pop ecx ; count of bytes to send
mov ebx, ecx ; need the length later
cmp ebx, 0
jz btp_001
mov edi, edx
add edi, 40
cld
rep movsb ; copy the data across
btp_001:
; we have edx as IPbuffer ptr.
; Fill in the TCP checksum
; First, fill in pseudoheader
mov eax, [edx + 12]
mov [pseudoHeader], eax
mov eax, [edx + 16]
mov [pseudoHeader+4], eax
mov ax, 0x0600 ; 0 + protocol
mov [pseudoHeader+8], ax
add ebx, 20
mov eax, ebx
mov [pseudoHeader+10], ah
mov [pseudoHeader+11], al
mov eax, pseudoHeader
mov [checkAdd1], eax
mov [checkSize1], word 12
mov eax, edx
add eax, 20
mov [checkAdd2], eax
mov eax, ebx
mov [checkSize2], ax
call checksum
; store it in the TCP checksum ( in the correct order! )
mov ax, [checkResult]
mov [edx + 20 + 16], ah
mov [edx + 20 + 17], al
; Fill in the IP header checksum
GET_IHL eax,edx ; get IP-Header length
stdcall checksum_jb,edx,eax ; buf_ptr, buf_size
mov [edx + 10], ah
mov [edx + 11], al
ret
; Increments the 32 bit value pointed to by esi in internet order
inc_inet_esi:
push eax
add esi, 3
mov al, byte[esi]
inc al
mov byte[esi], al
cmp al, 0
jnz iie_exit
dec esi
mov al, byte[esi]
inc al
mov byte[esi], al
cmp al, 0
jnz iie_exit
dec esi
mov al, byte[esi]
inc al
mov byte[esi], al
cmp al, 0
jnz iie_exit
dec esi
mov al, byte[esi]
inc al
mov byte[esi], al
iie_exit:
pop eax
ret
; Increments the 32 bit value pointed to by esi in internet order
; by the value in ecx
add_inet_esi:
push eax
mov al, [esi]
shl eax, 8
inc esi
mov al, [esi]
shl eax, 8
inc esi
mov al, [esi]
shl eax, 8
inc esi
mov al, [esi]
add eax, ecx
mov [esi], al
dec esi
shr eax, 8
mov [esi], al
dec esi
shr eax, 8
mov [esi], al
dec esi
shr eax, 8
mov [esi], al
pop eax
ret
iglobal
TCBStateHandler:
dd stateTCB_LISTEN
dd stateTCB_SYN_SENT
dd stateTCB_SYN_RECEIVED
dd stateTCB_ESTABLISHED
dd stateTCB_FIN_WAIT_1
dd stateTCB_FIN_WAIT_2
dd stateTCB_CLOSE_WAIT
dd stateTCB_CLOSING
dd stateTCB_LAST_ACK
dd stateTCB_TIME_WAIT
dd stateTCB_CLOSED
endg
;***************************************************************************
; Function
; tcpStateMachine
;
; Description
; TCP state machine
; This is a kernel function, called by tcp_rx
;
; IP buffer address given in edx
; Socket/TCB address in [eax + sockets]
;
; The IP buffer will be released by the caller
;***************************************************************************
tcpStateMachine:
mov ebx, sockets
add ebx, eax
mov [sktAddr], ebx
; as a packet has been received, update the TCB timer
mov ecx, TWOMSL
mov [ebx + 32], ecx
; If the received packet has an ACK bit set,
; remove any packets in the resend queue that this
; received packet acknowledges
pusha
mov cl, [edx + 33]
and cl, 0x10
cmp cl, 0x10
jne tsm001 ; No ACK, so no data yet
; get skt number in al
shr eax, 12
; The ack number is in [edx + 28], inet format
; skt in al
mov esi, resendQ
mov ecx, 0
t001:
cmp ecx, NUMRESENDENTRIES
je t003 ; None left
cmp [esi], al
je t002 ; found one
inc ecx
add esi, 4
jmp t001
t002: ; Can we delete this buffer?
; If yes, goto t004. No, goto t001
; Get packet data address
push ecx
inc ecx
; Now get buffer location, and copy buffer across. argh! more copying,,
mov edi, resendBuffer - IPBUFFSIZE
t002a:
add edi, IPBUFFSIZE
loop t002a
; we have dest buffer location in edi. incoming packet in edx.
; Get this packets sequence number
; preserve al, ecx, esi, edx
mov cl, [edi + 24]
shl ecx, 8
mov cl, [edi + 25]
shl ecx, 8
mov cl, [edi + 26]
shl ecx, 8
mov cl, [edi + 27]
movzx ebx, byte [edi + 3]
mov bh, [edi + 2]
sub ebx, 40
add ecx, ebx ; ecx is now seq# of last byte +1, intel format
; get recievd ack #, in intel format
mov bl, [edx + 28]
shl ebx, 8
mov bl, [edx + 29]
shl ebx, 8
mov bl, [edx + 30]
shl ebx, 8
mov bl, [edx + 31]
cmp ebx, ecx ; Finally. ecx = rx'ed ack. ebx = last byte in que
; DANGER! need to handle case that we have just
; passed the 2**32, and wrapped round!
pop ecx
jae t004 ; if rx > old, delete old
inc ecx
add esi, 4
jmp t001
t004:
dec dword [arp_rx_count] ; ************ TEST ONLY!
mov [esi], byte 0xFF
inc ecx
add esi, 4
jmp t001
t003:
tsm001:
popa
; Call handler for given TCB state
mov ebx, [eax + sockets+28]
cmp ebx, TCB_LISTEN
jb tsm_exit
cmp ebx, TCB_CLOSED
ja tsm_exit
dec ebx
call dword [TCBStateHandler+ebx*4]
tsm_exit:
ret
stateTCB_LISTEN:
; In this case, we are expecting a SYN packet
; For now, if the packet is a SYN, process it, and send a response
; If not, ignore it
; Look at control flags
mov bl, [edx + 33]
and bl, 0x02
cmp bl, 0x02
jnz stl_exit
; We have a SYN. update the socket with this IP packets details,
; And send a response
mov ebx, [edx + 12] ; IP source address
mov [eax + sockets + 16], ebx
mov bx, [edx + 20] ; IP source port
mov [eax + sockets + 20], bx
mov ebx, [edx + 24] ; IRS
mov [eax + sockets + 40], ebx
mov [eax + sockets + 56], ebx
mov esi, sockets
add esi, eax
add esi, 56
call inc_inet_esi ; RCV.NXT
mov ebx, [eax + sockets + 36] ; ISS
mov [eax + sockets + 48], ebx ; SND.NXT
; Now construct the response, and queue for sending by IP
mov eax, EMPTY_QUEUE
call dequeue
cmp ax, NO_BUFFER
je stl_exit
push eax
mov bl, 0x12 ; SYN + ACK
mov ecx, 0
mov esi, 0
call buildTCPPacket
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [ sktAddr ]
mov ecx, [ ecx + 16 ]
cmp edx, ecx
jne stl_notlocal
mov eax, IPIN_QUEUE
stl_notlocal:
; Send it.
pop ebx
call queue
mov ebx, TCB_SYN_RECEIVED
mov esi, [sktAddr]
mov [esi + 28], ebx
; increament SND.NXT in socket
add esi, 48
call inc_inet_esi
stl_exit:
ret
stateTCB_SYN_SENT:
; We are awaiting an ACK to our SYN, with a SYM
; Look at control flags - expecting an ACK
mov bl, [edx + 33]
and bl, 0x12
cmp bl, 0x12
jnz stss_exit
mov ebx, TCB_ESTABLISHED
mov esi, [sktAddr]
mov [esi + 28], ebx
; Store the recv.nxt field
mov eax, [edx + 24]
; Update our recv.nxt field
mov esi, [sktAddr]
add esi, 56
mov [esi], eax
call inc_inet_esi
; Send an ACK
; Now construct the response, and queue for sending by IP
mov eax, EMPTY_QUEUE
call dequeue
cmp ax, NO_BUFFER
je stss_exit
push eax
mov bl, 0x10 ; ACK
mov ecx, 0
mov esi, 0
call buildTCPPacket
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [ sktAddr ]
mov ecx, [ ecx + 16 ]
cmp edx, ecx
jne stss_notlocal
mov eax, IPIN_QUEUE
stss_notlocal:
; Send it.
pop ebx
call queue
stss_exit:
ret
stateTCB_SYN_RECEIVED:
; In this case, we are expecting an ACK packet
; For now, if the packet is an ACK, process it,
; If not, ignore it
; Look at control flags - expecting an ACK
mov bl, [edx + 33]
and bl, 0x10
cmp bl, 0x10
jnz stsr_exit
mov ebx, TCB_ESTABLISHED
mov esi, [sktAddr]
mov [esi + 28], ebx
stsr_exit:
ret
stateTCB_ESTABLISHED:
; Here we are expecting data, or a request to close
; OR both...
; Did we receive a FIN or RST?
mov bl, [edx + 33]
and bl, 0x05
cmp bl, 0
je ste_chkack
; It was a fin or reset.
; Remove resend entries from the queue - I dont want to send any more data
pusha
mov ebx, [sktAddr]
sub ebx, sockets
shr ebx, 12 ; get skt #
mov esi, resendQ
mov ecx, 0
ste001:
cmp ecx, NUMRESENDENTRIES
je ste003 ; None left
cmp [esi], bl
je ste002 ; found one
inc ecx
add esi, 4
jmp ste001
ste002:
dec dword [arp_rx_count] ; ************ TEST ONLY!
mov [esi], byte 0xFF
jmp ste001
ste003:
popa
; was it a reset?
mov bl, [edx + 33]
and bl, 0x04
cmp bl, 0x04
jne ste003a
mov esi, [sktAddr]
mov ebx, TCB_CLOSED
mov [esi + 28], ebx
jmp ste_exit
ste003a:
; Send an ACK to that fin, and enter closewait state
mov esi, [sktAddr]
mov ebx, TCB_CLOSE_WAIT
mov [esi + 28], ebx
add esi, 56
mov eax, [esi] ; save original
call inc_inet_esi
;; jmp ste_ack - NO, there may be data
ste_chkack:
; Check that we received an ACK
mov bl, [edx + 33]
and bl, 0x10
cmp bl, 0x10
jnz ste_exit
; TODO - done, I think!
; First, look at the incoming window. If this is less than or equal to 1024,
; Set the socket window timer to 1. This will stop an additional packets being
; queued.
; ** I may need to tweak this value, since I do not know how many packets are already queued
mov ch, [edx + 34]
mov cl, [edx + 35]
cmp cx, 1024
ja ste004
mov ecx, [sktAddr]
mov [ecx+72], dword 1
ste004:
; OK, here is the deal
; My recv.nct field holds the seq of the expected next rec byte
; if the recevied sequence number is not equal to this, do not
; increment the recv.nxt field, do not copy data - just send a
; repeat ack.
; recv.nxt is in dword [edx+24], in inext format
; recv seq is in [sktAddr]+56, in inet format
; just do a comparision
mov ecx, [sktAddr]
add ecx, 56
cmp [ecx - 56 + 28], dword TCB_CLOSE_WAIT
mov ecx, [ecx]
jne stenofin
mov ecx, eax
stenofin:
cmp ecx, [edx+24]
jne ste_ack
; Read the data bytes, store in socket buffer
xor ecx, ecx
mov ch, [edx + 2]
mov cl, [edx + 3]
sub ecx, 40 ; Discard 40 bytes of header
cmp ecx, 0
jnz ste_data ; Read data, if any
; If we had received a fin, we need to ACK it.
mov esi, [sktAddr]
mov ebx, [esi + 28]
cmp ebx, TCB_CLOSE_WAIT
jz ste_ack
jnz ste_exit
ste_data:
push ecx
mov esi, [sktAddr]
add [esi + 24], ecx ; increment the count of bytes in buffer
mov eax, [esi + 4] ; get socket owner PID
push eax
mov eax, [esi + 24] ; get # of bytes already in buffer
; point to the location to store the data
add esi, eax
sub esi, ecx
add esi, SOCKETHEADERSIZE
add edx, 40 ; edx now points to the data
mov edi, esi
mov esi, edx
cld
rep movsb ; copy the data across
; flag an event to the application
pop eax
mov ecx,1
mov esi,TASK_DATA+TASKDATA.pid
news:
cmp [esi],eax
je foundPID1
inc ecx
add esi,0x20
cmp ecx,[TASK_COUNT]
jbe news
foundPID1:
shl ecx,8
or dword [ecx+SLOT_BASE+APPDATA.event_mask],dword 10000000b ; stack event
pop ecx
; Update our recv.nxt field
mov esi, [sktAddr]
add esi, 56
call add_inet_esi
ste_ack:
; Send an ACK
; Now construct the response, and queue for sending by IP
mov eax, EMPTY_QUEUE
call dequeue
cmp ax, NO_BUFFER
je ste_exit
push eax
mov bl, 0x10 ; ACK
mov ecx, 0
mov esi, 0
call buildTCPPacket
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [ sktAddr ]
mov ecx, [ ecx + 16 ]
cmp edx, ecx
jne ste_notlocal
mov eax, IPIN_QUEUE
ste_notlocal:
; Send it.
pop ebx
call queue
ste_exit:
ret
stateTCB_FIN_WAIT_1:
; We can either receive an ACK of a fin, or a fin
mov bl, [edx + 33]
and bl, 0x10
cmp bl, 0x10
jnz stfw1_001
; It was an ACK
mov esi, [sktAddr]
mov ebx, TCB_FIN_WAIT_2
mov [esi + 28], ebx
jmp stfw1_exit
stfw1_001:
; It must be a fin then
mov esi, [sktAddr]
mov ebx, TCB_CLOSING
mov [esi + 28], ebx
add esi, 56
call inc_inet_esi
; Send an ACK
mov eax, EMPTY_QUEUE
call dequeue
cmp ax, NO_BUFFER
je stfw1_exit
push eax
mov bl, 0x10 ; ACK
mov ecx, 0
mov esi, 0
call buildTCPPacket
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [ sktAddr ]
mov ecx, [ ecx + 16 ]
cmp edx, ecx
jne stfw1_notlocal
mov eax, IPIN_QUEUE
stfw1_notlocal:
; Send it.
pop ebx
call queue
stfw1_exit:
ret
stateTCB_FIN_WAIT_2:
mov esi, [sktAddr]
; Get data length
xor ecx, ecx
mov ch, [edx+2]
mov cl, [edx+3]
sub ecx, 40
mov bl, [edx + 33]
and bl, 0x01
cmp bl, 0x01
jne stfw2001
; Change state, as we have a fin
mov ebx, TCB_TIME_WAIT
mov [esi + 28], ebx
inc ecx ; FIN is part of the sequence space
stfw2001:
add esi, 56
call add_inet_esi
; Send an ACK
mov eax, EMPTY_QUEUE
call dequeue
cmp ax, NO_BUFFER
je stfw2_exit
push eax
mov bl, 0x10 ; ACK
mov ecx, 0
mov esi, 0
call buildTCPPacket
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [ sktAddr ]
mov ecx, [ ecx + 16 ]
cmp edx, ecx
jne stfw2_notlocal
mov eax, IPIN_QUEUE
stfw2_notlocal:
; Send it.
pop ebx
call queue
; Only delete the socket if we received the FIN
mov bl, [edx + 33]
and bl, 0x01
cmp bl, 0x01
jne stfw2_exit
; mov edi, [sktAddr]
; delete the socket. Should really wait for 2MSL
; xor eax, eax
; mov ecx,SOCKETHEADERSIZE
; cld
; rep stosb
stfw2_exit:
ret
stateTCB_CLOSE_WAIT:
; Intentionally left empty
; socket_close_tcp handles this
ret
stateTCB_CLOSING:
; We can either receive an ACK of a fin, or a fin
mov bl, [edx + 33]
and bl, 0x10
cmp bl, 0x10
jnz stc_exit
; It was an ACK
mov edi, [sktAddr]
; delete the socket
xor eax, eax
mov ecx,SOCKETHEADERSIZE
cld
rep stosb
stc_exit:
ret
stateTCB_LAST_ACK:
; Look at control flags - expecting an ACK
mov bl, [edx + 33]
and bl, 0x10
cmp bl, 0x10
jnz stla_exit
mov edi, [sktAddr]
; delete the socket
xor eax, eax
mov ecx,SOCKETHEADERSIZE
cld
rep stosb
stla_exit:
ret
stateTCB_TIME_WAIT:
ret
stateTCB_CLOSED:
ret