;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; Copyright (C) KolibriOS team 2004-2008. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License ;;
;; ;;
;; TCP.INC ;;
;; ;;
;; TCP Processes for Menuet OS TCP/IP stack ;;
;; ;;
;; 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 ;;
;; ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
$Revision: 2971 $
; 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_TIMED_WAIT equ 10
TCB_CLOSED equ 11
TH_FIN = 0x01
TH_SYN = 0x02
TH_RST = 0x04
TH_PUSH = 0x08
TH_ACK = 0x10
TH_URG = 0x20
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
;
;***************************************************************************
proc tcp_tcb_handler stdcall uses ebx
; scan through all the sockets, decrementing active timers
mov ebx, net_sockets
cmp [ebx + SOCKET.NextPtr], 0
je .exit
;DEBUGF 1, "K : sockets:\n"
.next_socket:
mov ebx, [ebx + SOCKET.NextPtr]
or ebx, ebx
jz .exit
;DEBUGF 1, "K : %x-%x: %x-%x-%x-%u\n", [ebx + SOCKET.PID]:2, [ebx + SOCKET.Number]:2, [ebx + SOCKET.LocalPort]:4, [ebx + SOCKET.RemoteIP], [ebx + SOCKET.RemotePort]:4, [ebx + SOCKET.TCBState]
cmp [ebx + SOCKET.TCBTimer], 0
jne .decrement_tcb
cmp [ebx + SOCKET.wndsizeTimer], 0
jne .decrement_wnd
jmp .next_socket
.decrement_tcb:
; decrement it, delete socket if TCB timer = 0 & socket in timewait state
dec [ebx + SOCKET.TCBTimer]
jnz .next_socket
cmp [ebx + SOCKET.TCBState], TCB_TIMED_WAIT
jne .next_socket
push [ebx + SOCKET.PrevPtr]
stdcall net_socket_free, ebx
pop ebx
jmp .next_socket
.decrement_wnd:
; TODO - prove it works!
dec [ebx + SOCKET.wndsizeTimer]
jmp .next_socket
.exit:
ret
endp
;***************************************************************************
; Function
; tcp_tx_handler
;
; Description
; Handles queued TCP data
; This is a kernel function, called by stack_handler
;
;***************************************************************************
proc tcp_tx_handler stdcall
; 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
.next_resendq:
cmp ecx, NUMRESENDENTRIES
je .exit ; None left
cmp dword[esi + 4], 0
jne @f ; found one
inc ecx
add esi, 8
jmp .next_resendq
@@: ; we have one. decrement it's timer by 1
dec word[esi + 2]
jz @f
inc ecx
add esi, 8
jmp .next_resendq ; Timer not zero, so move on
@@:
xor ebx, ebx
; 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]
jnz @f
; retries now 0, so delete from queue
xchg [esi + 4], ebx
@@: ; resend packet
pushad
mov eax, EMPTY_QUEUE
call dequeue
cmp ax, NO_BUFFER
jne .tth004z
; TODO - try again in 10ms.
test ebx, ebx
jnz @f
mov [esi + 4], ebx
@@: ; Mark it to expire in 10ms - 1 tick
mov byte[esi + 1], 1
mov word[esi + 2], 1
jmp .tth005
.tth004z:
; we have a buffer # in ax
push eax ecx
mov ecx, IPBUFFSIZE
mul ecx
add eax, IPbuffs
; we have the buffer address in eax
mov edi, eax
pop ecx
; Now get buffer location, and copy buffer across. argh! more copying,,
mov esi, resendBuffer
@@: add esi, IPBUFFSIZE
loop @b
; we have resend buffer location in esi
mov ecx, IPBUFFSIZE
; copy data across
push edi
cld
rep movsb
pop edi
; queue packet
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
cmp edx, [edi + IP_PACKET.DestinationAddress]
jne .not_local
mov eax, IPIN_QUEUE
.not_local:
pop ebx
call queue
.tth005:
popad
inc ecx
add esi, 8
jmp .next_resendq
.exit:
ret
endp
;***************************************************************************
; 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
;
;***************************************************************************
proc tcp_rx stdcall uses ebx
; 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 ebx, net_sockets
.next_socket.1:
mov ebx, [ebx + SOCKET.NextPtr]
or ebx, ebx
jz .next_socket.1.exit
; DEBUGF 1, "K : tcp_rx - 1.dport: %x - %x\n", [edx + 20 + TCP_PACKET.DestinationPort]:4, [ebx + SOCKET.LocalPort]:4
mov ax, [edx + 20 + TCP_PACKET.DestinationPort] ; get the dest. port from the TCP hdr
cmp [ebx + SOCKET.LocalPort], ax ; get the dest. port from the TCP hdr
jne .next_socket.1 ; different - try next socket
; DEBUGF 1, "K : tcp_rx - 1.addr: %x - %x\n", [edx + IP_PACKET.SourceAddress], [ebx + SOCKET.RemoteIP]
mov eax, [edx + IP_PACKET.SourceAddress] ; get the source IP Addr from the IP hdr
cmp [ebx + SOCKET.RemoteIP], eax ; compare with socket's remote IP
jne .next_socket.1 ; different - try next socket
; DEBUGF 1, "K : tcp_rx - 1.sport: %x - %x\n", [edx + 20 + TCP_PACKET.SourcePort]:4, [ebx + SOCKET.RemotePort]:4
mov ax, [edx + 20 + TCP_PACKET.SourcePort] ; get the source port from the TCP hdr
cmp [ebx + SOCKET.RemotePort], ax ; compare with socket's remote port
jne .next_socket.1 ; different - try next socket
; We have a complete match - use this socket
jmp .change_state
.next_socket.1.exit:
; 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 ebx, net_sockets
.next_socket.2:
mov ebx, [ebx + SOCKET.NextPtr]
or ebx, ebx
jz .next_socket.2.exit
; DEBUGF 1, "K : tcp_rx - 2.dport: %x - %x\n", [edx + 20 + TCP_PACKET.DestinationPort]:4, [ebx + SOCKET.LocalPort]:4
mov ax, [edx + 20 + TCP_PACKET.DestinationPort] ; get the dest. port from the TCP hdr
cmp [ebx + SOCKET.LocalPort], ax ; compare with socket's local port
jne .next_socket.2 ; different - try next socket
; DEBUGF 1, "K : tcp_rx - 2.addr: %x - %x\n", [edx + IP_PACKET.SourceAddress], [ebx + SOCKET.RemoteIP]
mov eax, [edx + IP_PACKET.SourceAddress] ; get the source IP Addr from the IP hdr
cmp [ebx + SOCKET.RemoteIP], eax ; compare with socket's remote IP
jne .next_socket.2 ; different - try next socket
; DEBUGF 1, "K : tcp_rx - 2.sport: 0000 - %x\n", [ebx + SOCKET.RemotePort]:4
cmp [ebx + SOCKET.RemotePort], 0 ; only match a remote socket of 0
jne .next_socket.2 ; different - try next socket
; We have a complete match - use this socket
jmp .change_state
.next_socket.2.exit:
; 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 ebx, net_sockets
.next_socket.3:
mov ebx, [ebx + SOCKET.NextPtr]
or ebx, ebx
jz .next_socket.3.exit
; DEBUGF 1, "K : tcp_rx - 3.dport: %x - %x\n", [edx + 20 + TCP_PACKET.DestinationPort]:4, [ebx + SOCKET.LocalPort]:4
mov ax, [edx + 20 + TCP_PACKET.DestinationPort] ; get destination port from the TCP hdr
cmp [ebx + SOCKET.LocalPort], ax ; compare with socket's local port
jne .next_socket.3 ; different - try next socket
; DEBUGF 1, "K : tcp_rx - 3.addr: 00000000 - %x\n", [ebx + SOCKET.RemoteIP]
cmp [ebx + SOCKET.RemoteIP], 0 ; only match a socket remote IP of 0
jne .next_socket.3 ; different - try next socket
; DEBUGF 1, "K : tcp_rx - 3.sport: 0000 - %x\n", [ebx + SOCKET.RemotePort]:4
cmp [ebx + SOCKET.RemotePort], 0 ; only match a remote socket of 0
jne .next_socket.3 ; different - try next socket
; We have a complete match - use this socket
jmp .change_state
.next_socket.3.exit:
; If we got here, we need to reject the packet
DEBUGF 1, "K : tcp_rx - dumped\n"
DEBUGF 1, "K : --------: %x-%x-%x (flags: %x)\n", [edx + 20 + TCP_PACKET.DestinationPort]:4, [edx + IP_PACKET.SourceAddress], [edx + 20 + TCP_PACKET.SourcePort]:4, [edx + 20 + TCP_PACKET.Flags]:2
inc [dumped_rx_count]
jmp .exit
.change_state:
; We have a valid socket/TCB, so call the TCB State Machine for that skt.
; socket is pointed to by ebx
; IP packet is pointed to by edx
; IP buffer number is on stack ( it will be popped at the end)
stdcall tcpStateMachine, ebx
.exit:
pop eax
call freeBuff
ret
endp
;***************************************************************************
; 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
;
;***************************************************************************
proc build_tcp_packet stdcall, sockAddr:DWORD
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 + 20 + TCP_PACKET.Flags], bl ; TCP flags
mov ebx, [sockAddr]
; 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 + SOCKET.LocalIP]
mov [edx + IP_PACKET.SourceAddress], eax
mov eax, [ebx + SOCKET.RemoteIP]
mov [edx + IP_PACKET.DestinationAddress], eax
mov [edx + IP_PACKET.VersionAndIHL], 0x45
mov [edx + IP_PACKET.TypeOfService], 0
pop eax ; Get the TCP data length
push eax
add eax, 20 + 20 ; add IP header and TCP header lengths
rol ax, 8
mov [edx + IP_PACKET.TotalLength], ax
mov [edx + IP_PACKET.Identification], 0
mov [edx + IP_PACKET.FlagsAndFragmentOffset], 0x0040
mov [edx + IP_PACKET.TimeToLive], 0x20
mov [edx + IP_PACKET.Protocol], PROTOCOL_TCP
; Checksum left unfilled
mov [edx + IP_PACKET.HeaderChecksum], 0
; Fill in the TCP header (some data is in the socket descriptor)
mov ax, [ebx + SOCKET.LocalPort]
mov [edx + 20 + TCP_PACKET.SourcePort], ax ; Local Port
mov ax, [ebx + SOCKET.RemotePort]
mov [edx + 20 + TCP_PACKET.DestinationPort], ax ; desitination Port
; Checksum left unfilled
mov [edx + 20 + TCP_PACKET.Checksum], 0
; sequence number
mov eax, [ebx + SOCKET.SND_NXT]
mov [edx + 20 + TCP_PACKET.SequenceNumber], eax
; ack number
mov eax, [ebx + SOCKET.RCV_NXT]
mov [edx + 20 + TCP_PACKET.AckNumber], eax
; window ( 0x2000 is default ).I could accept 4KB, fa0, ( skt buffer size)
; 768 bytes seems better
mov [edx + 20 + TCP_PACKET.Window], 0x0003
; Urgent pointer (0)
mov [edx + 20 + TCP_PACKET.UrgentPointer], 0
; data offset ( 0x50 )
mov [edx + 20 + TCP_PACKET.DataOffset], 0x50
pop ecx ; count of bytes to send
mov ebx, ecx ; need the length later
cmp ebx, 0
jz @f
mov edi, edx
add edi, 40
cld
rep movsb ; copy the data across
@@: ; we have edx as IPbuffer ptr.
; Fill in the TCP checksum
; First, fill in pseudoheader
mov eax, [edx + IP_PACKET.SourceAddress]
mov [pseudoHeader], eax
mov eax, [edx + IP_PACKET.DestinationAddress]
mov [pseudoHeader + 4], eax
mov word[pseudoHeader + 8], PROTOCOL_TCP shl 8 + 0
add ebx, 20
mov [pseudoHeader + 10], bh
mov [pseudoHeader + 11], bl
mov eax, pseudoHeader
mov [checkAdd1], eax
mov word[checkSize1], 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]
rol ax, 8
mov [edx + 20 + TCP_PACKET.Checksum], ax
; Fill in the IP header checksum
GET_IHL eax, edx ; get IP-Header length
stdcall checksum_jb, edx, eax ; buf_ptr, buf_size
rol ax, 8
mov [edx + IP_PACKET.HeaderChecksum], ax
ret
endp
; Increments the 32 bit value pointed to by esi in internet order
proc inc_inet_esi stdcall
push eax
mov eax, [esi]
bswap eax
inc eax
bswap eax
mov [esi], eax
pop eax
ret
endp
; Increments the 32 bit value pointed to by esi in internet order
; by the value in ecx
proc add_inet_esi stdcall
push eax
mov eax, [esi]
bswap eax
add eax, ecx
bswap eax
mov [esi], eax
pop eax
ret
endp
iglobal
TCBStateHandler dd \
stateTCB_LISTEN, \
stateTCB_SYN_SENT, \
stateTCB_SYN_RECEIVED, \
stateTCB_ESTABLISHED, \
stateTCB_FIN_WAIT_1, \
stateTCB_FIN_WAIT_2, \
stateTCB_CLOSE_WAIT, \
stateTCB_CLOSING, \
stateTCB_LAST_ACK, \
stateTCB_TIME_WAIT, \
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 ebx
;
; The IP buffer will be released by the caller
;***************************************************************************
proc tcpStateMachine stdcall, sockAddr:DWORD
; as a packet has been received, update the TCB timer
mov [ebx + SOCKET.TCBTimer], TWOMSL
; If the received packet has an ACK bit set,
; remove any packets in the resend queue that this
; received packet acknowledges
pushad
test [edx + 20 + TCP_PACKET.Flags], TH_ACK
jz .call_handler ; No ACK, so no data yet
; get skt number in eax
stdcall net_socket_addr_to_num, ebx
; The ack number is in [edx + 28], inet format
; skt in eax
mov esi, resendQ
xor ecx, ecx
.next_resendq:
cmp ecx, NUMRESENDENTRIES
je .call_handler ; None left
cmp [esi + 4], eax
je @f ; found one
inc ecx
add esi, 8
jmp .next_resendq
@@: ; Can we delete this buffer?
; If yes, goto @@. No, goto .next_resendq
; Get packet data address
push ecx
; Now get buffer location, and copy buffer across. argh! more copying,,
imul edi, ecx, IPBUFFSIZE
add edi, resendBuffer
; we have dest buffer location in edi. incoming packet in edx.
; Get this packets sequence number
; preserve al, ecx, esi, edx
mov ecx, [edi + 20 + TCP_PACKET.SequenceNumber]
bswap ecx
movzx ebx, word[edi + 2]
xchg bl, bh
sub ebx, 40
add ecx, ebx ; ecx is now seq# of last byte +1, intel format
; get recievd ack #, in intel format
mov ebx, [edx + 20 + TCP_PACKET.AckNumber]
bswap ebx
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 @f ; if rx > old, delete old
inc ecx
add esi, 8
jmp .next_resendq
@@: mov dword[esi + 4], 0
inc ecx
add esi, 8
jmp .next_resendq
.call_handler:
popad
; Call handler for given TCB state
mov eax, [ebx + SOCKET.TCBState]
cmp eax, TCB_LISTEN
jb .exit
cmp eax, TCB_CLOSED
ja .exit
stdcall [TCBStateHandler + (eax - 1) * 4], [sockAddr]
.exit:
ret
endp
proc stateTCB_LISTEN stdcall, sockAddr:DWORD
; 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
test [edx + 20 + TCP_PACKET.Flags], TH_SYN
jz .exit
; We have a SYN. update the socket with this IP packets details,
; And send a response
mov eax, [edx + IP_PACKET.SourceAddress]
mov [ebx + SOCKET.RemoteIP], eax
mov ax, [edx + 20 + TCP_PACKET.SourcePort]
mov [ebx + SOCKET.RemotePort], ax
mov eax, [edx + 20 + TCP_PACKET.SequenceNumber]
mov [ebx + SOCKET.IRS], eax
mov [ebx + SOCKET.RCV_NXT], eax
lea esi, [ebx + SOCKET.RCV_NXT]
call inc_inet_esi ; RCV.NXT
mov eax, [ebx + SOCKET.ISS]
mov [ebx + SOCKET.SND_NXT], eax
; Now construct the response, and queue for sending by IP
mov eax, EMPTY_QUEUE
call dequeue
cmp ax, NO_BUFFER
je .exit
push eax
mov bl, TH_SYN + TH_ACK
xor ecx, ecx
xor esi, esi
stdcall build_tcp_packet, [sockAddr]
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [sockAddr]
cmp edx, [ecx + SOCKET.RemoteIP]
jne .not_local
mov eax, IPIN_QUEUE
.not_local:
; Send it.
pop ebx
call queue
mov esi, [sockAddr]
mov [esi + SOCKET.TCBState], TCB_SYN_RECEIVED
; increment SND.NXT in socket
add esi, SOCKET.SND_NXT
call inc_inet_esi
.exit:
ret
endp
proc stateTCB_SYN_SENT stdcall, sockAddr:DWORD
; We are awaiting an ACK to our SYN, with a SYM
; Look at control flags - expecting an ACK
mov al, [edx + 20 + TCP_PACKET.Flags]
and al, TH_SYN + TH_ACK
cmp al, TH_SYN + TH_ACK
je .syn_ack
test al, TH_SYN
jz .exit
mov [ebx + SOCKET.TCBState], TCB_SYN_RECEIVED
push TH_SYN + TH_ACK
jmp .send
.syn_ack:
mov [ebx + SOCKET.TCBState], TCB_ESTABLISHED
push TH_ACK
.send:
; Store the recv.nxt field
mov eax, [edx + 20 + TCP_PACKET.SequenceNumber]
; Update our recv.nxt field
mov [ebx + SOCKET.RCV_NXT], eax
lea esi, [ebx + SOCKET.RCV_NXT]
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
pop ebx
je .exit
push eax
xor ecx, ecx
xor esi, esi
stdcall build_tcp_packet, [sockAddr]
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [sockAddr]
cmp edx, [ecx + SOCKET.RemoteIP]
jne .not_local
mov eax, IPIN_QUEUE
.not_local:
; Send it.
pop ebx
call queue
.exit:
ret
endp
proc stateTCB_SYN_RECEIVED stdcall, sockAddr:DWORD
; In this case, we are expecting an ACK packet
; For now, if the packet is an ACK, process it,
; If not, ignore it
test [edx + 20 + TCP_PACKET.Flags], TH_RST
jz .check_ack
push [ebx + SOCKET.OrigRemotePort] [ebx + SOCKET.OrigRemoteIP]
pop [ebx + SOCKET.RemoteIP] [ebx + SOCKET.RemotePort]
mov [ebx + SOCKET.TCBState], TCB_LISTEN
jmp .exit
.check_ack:
; Look at control flags - expecting an ACK
test [edx + 20 + TCP_PACKET.Flags], TH_ACK
jz .exit
mov [ebx + SOCKET.TCBState], TCB_ESTABLISHED
.exit:
ret
endp
proc stateTCB_ESTABLISHED stdcall, sockAddr:DWORD
; Here we are expecting data, or a request to close
; OR both...
; Did we receive a FIN or RST?
test [edx + 20 + TCP_PACKET.Flags], TH_FIN
jz .check_ack
; It was a fin or reset.
; Remove resend entries from the queue - I dont want to send any more data
pushad
; get skt #
stdcall net_socket_addr_to_num, ebx
mov esi, resendQ
mov ecx, 0
.next_resendq:
cmp ecx, NUMRESENDENTRIES
je .last_resendq ; None left
cmp [esi + 4], eax
je @f ; found one
inc ecx
add esi, 8
jmp .next_resendq
@@: mov dword[esi + 4], 0
inc ecx
add esi, 8
jmp .next_resendq
.last_resendq:
popad
@@: ; Send an ACK to that fin, and enter closewait state
mov [ebx + SOCKET.TCBState], TCB_CLOSE_WAIT
lea esi, [ebx + SOCKET.RCV_NXT]
mov eax, [esi] ; save original
call inc_inet_esi
;; jmp ste_ack - NO, there may be data
.check_ack:
; Check that we received an ACK
test [edx + 20 + TCP_PACKET.Flags], TH_ACK
jz .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 cx, [edx + 20 + TCP_PACKET.Window]
xchg cl, ch
cmp cx, 1024
ja @f
mov [ebx + SOCKET.wndsizeTimer], 1
@@: ; 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 inet format
; recv seq is in [sktAddr]+56, in inet format
; just do a comparision
mov ecx, [ebx + SOCKET.RCV_NXT]
cmp [ebx + SOCKET.TCBState], TCB_CLOSE_WAIT
jne @f
mov ecx, eax
@@: cmp ecx, [edx + 20 + TCP_PACKET.SequenceNumber]
jne .ack
; Read the data bytes, store in socket buffer
movzx ecx, [edx + IP_PACKET.TotalLength]
xchg cl, ch
sub ecx, 40 ; Discard 40 bytes of header
ja .data ; Read data, if any
; If we had received a fin, we need to ACK it.
cmp [ebx + SOCKET.TCBState], TCB_CLOSE_WAIT
je .ack
jmp .exit
.data:
push ebx
add ebx, SOCKET.lock
call wait_mutex
pop ebx
push ecx
push [ebx + SOCKET.PID] ; get socket owner PID
mov eax, [ebx + SOCKET.rxDataCount]
add eax, ecx
cmp eax, SOCKETBUFFSIZE - SOCKETHEADERSIZE
ja .overflow
mov [ebx + SOCKET.rxDataCount], eax ; increment the count of bytes in buffer
; point to the location to store the data
lea edi, [ebx + eax + SOCKETHEADERSIZE]
sub edi, ecx
add edx, 40 ; edx now points to the data
mov esi, edx
cld
rep movsb ; copy the data across
mov [ebx + SOCKET.lock], 0 ; release mutex
; flag an event to the application
pop eax
mov ecx, 1
mov esi, TASK_DATA + TASKDATA.pid
.next_pid:
cmp [esi], eax
je .found_pid
inc ecx
add esi, 0x20
cmp ecx, [TASK_COUNT]
jbe .next_pid
.found_pid:
shl ecx, 8
or [ecx + SLOT_BASE + APPDATA.event_mask], EVENT_NETWORK ; stack event
pop ecx
; Update our recv.nxt field
lea esi, [ebx + SOCKET.RCV_NXT]
call add_inet_esi
.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 .exit
push eax
mov bl, TH_ACK
xor ecx, ecx
xor esi, esi
stdcall build_tcp_packet, [sockAddr]
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [sockAddr]
cmp edx, [ecx + SOCKET.RemoteIP]
jne .not_local
mov eax, IPIN_QUEUE
.not_local:
; Send it.
pop ebx
call queue
.exit:
ret
.overflow:
; no place in buffer
; so simply restore stack and exit
pop eax ecx
mov [ebx + SOCKET.lock], 0
ret
endp
proc stateTCB_FIN_WAIT_1 stdcall, sockAddr:DWORD
; We can either receive an ACK of a fin, or a fin
mov al, [edx + 20 + TCP_PACKET.Flags]
and al, TH_FIN + TH_ACK
cmp al, TH_ACK
jne @f
; It was an ACK
mov [ebx + SOCKET.TCBState], TCB_FIN_WAIT_2
jmp .exit
@@: mov [ebx + SOCKET.TCBState], TCB_CLOSING
cmp al, TH_FIN
je @f
mov [ebx + SOCKET.TCBState], TCB_TIMED_WAIT
@@: lea esi, [ebx + SOCKET.RCV_NXT]
call inc_inet_esi
; Send an ACK
mov eax, EMPTY_QUEUE
call dequeue
cmp ax, NO_BUFFER
je .exit
push eax
mov bl, TH_ACK
xor ecx, ecx
xor esi, esi
stdcall build_tcp_packet, [sockAddr]
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [sockAddr]
cmp edx, [ecx + SOCKET.RemoteIP]
jne .not_local
mov eax, IPIN_QUEUE
.not_local:
; Send it.
pop ebx
call queue
.exit:
ret
endp
proc stateTCB_FIN_WAIT_2 stdcall, sockAddr:DWORD
test [edx + 20 + TCP_PACKET.Flags], TH_FIN
jz .exit
; Change state, as we have a fin
mov [ebx + SOCKET.TCBState], TCB_TIMED_WAIT
lea esi, [ebx + SOCKET.RCV_NXT]
call inc_inet_esi
; Send an ACK
mov eax, EMPTY_QUEUE
call dequeue
cmp ax, NO_BUFFER
je .exit
push eax
mov bl, TH_ACK
xor ecx, ecx
xor esi, esi
stdcall build_tcp_packet, [sockAddr]
mov eax, NET1OUT_QUEUE
mov edx, [stack_ip]
mov ecx, [sockAddr]
cmp edx, [ecx + SOCKET.RemoteIP]
jne .not_local
mov eax, IPIN_QUEUE
.not_local:
; Send it.
pop ebx
call queue
.exit:
ret
endp
proc stateTCB_CLOSE_WAIT stdcall, sockAddr:DWORD
; Intentionally left empty
; socket_close_tcp handles this
ret
endp
proc stateTCB_CLOSING stdcall, sockAddr:DWORD
; We can either receive an ACK of a fin, or a fin
test [edx + 20 + TCP_PACKET.Flags], TH_ACK
jz .exit
mov [ebx + SOCKET.TCBState], TCB_TIMED_WAIT
.exit:
ret
endp
proc stateTCB_LAST_ACK stdcall, sockAddr:DWORD
; Look at control flags - expecting an ACK
test [edx + 20 + TCP_PACKET.Flags], TH_ACK
jz .exit
; delete the socket
stdcall net_socket_free, ebx
.exit:
ret
endp
proc stateTCB_TIME_WAIT stdcall, sockAddr:DWORD
ret
endp
proc stateTCB_CLOSED stdcall, sockAddr:DWORD
ret
endp