;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;; ;; Copyright (C) KolibriOS team 2004-2013. All rights reserved. ;; ;; Distributed under terms of the GNU General Public License ;; ;; ;; ;; 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: 3407 $ ;----------------------------------------------------------------- ; ; TCP_input: ; ; Add a segment to the incoming TCP queue ; ; IN: [esp] = ptr to buffer ; [esp+4] = buffer size (dont care) ; ebx = ptr to device struct ; ecx = segment size ; esi = ptr to TCP segment ; edi = ptr to ipv4 source address, followed by ipv4 dest address ; ; OUT: / ; ;----------------------------------------------------------------- align 4 TCP_input: ; record the current time mov eax, [timer_ticks] ; in 1/100 seconds mov [esp + 4], eax push ebx ecx esi edi ; mind the order mov esi, esp pushf cli add_to_queue TCP_queue, TCP_QUEUE_SIZE, sizeof.TCP_queue_entry, .fail popf add esp, sizeof.TCP_queue_entry call NET_ptr_to_num4 inc [TCP_segments_rx + edi] xor edx, edx mov eax, [TCP_input_event] mov ebx, [eax + EVENT.id] xor esi, esi call raise_event ret .fail: popf DEBUGF DEBUG_NETWORK_VERBOSE, "TCP incoming queue is full, discarding packet!\n" call NET_ptr_to_num4 inc [TCP_segments_missed + edi] add esp, sizeof.TCP_queue_entry - 8 call NET_packet_free add esp, 4 ret align 4 TCP_process_input: xor esi, esi mov ecx, MANUAL_DESTROY call create_event mov [TCP_input_event], eax .wait: mov eax, [TCP_input_event] mov ebx, [eax + EVENT.id] call wait_event .loop: get_from_queue TCP_queue, TCP_QUEUE_SIZE, sizeof.TCP_queue_entry, .wait push [esi + TCP_queue_entry.timestamp] push [esi + TCP_queue_entry.buffer_ptr] mov ebx, [esi + TCP_queue_entry.device_ptr] mov ecx, [esi + TCP_queue_entry.segment_size] mov edi, [esi + TCP_queue_entry.ip_ptr] ; ptr to ipv4 source address, followed by ipv4 destination address mov esi, [esi + TCP_queue_entry.segment_ptr] ; change esi last DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: size=%u time=%d\n", ecx, [timer_ticks] mov edx, esi cmp ebx, LOOPBACK_DEVICE je .checksum_ok ; re-calculate the checksum (if not already done by hw) ; test [ebx + NET_DEVICE.hwacc], HWACC_TCP_IPv4_IN ; jnz .checksum_ok push ecx esi pushw [esi + TCP_header.Checksum] mov [esi + TCP_header.Checksum], 0 TCP_checksum (edi), (edi+4) pop cx ; previous checksum cmp cx, dx pop edx ecx jne .drop_no_socket .checksum_ok: ; Verify the data offset and [edx + TCP_header.DataOffset], 0xf0 ; Calculate TCP segment header size (throwing away unused reserved bits in TCP header) shr [edx + TCP_header.DataOffset], 2 cmp [edx + TCP_header.DataOffset], sizeof.TCP_header ; Now see if it's at least the size of a standard TCP header jb .drop_no_socket ; If not, drop the packet movzx eax, [edx + TCP_header.DataOffset] sub ecx, eax ; substract TCP header size from total segment size jb .drop_no_socket ; If total segment size is less then the advertised header size, drop packet DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: %u bytes of data\n", ecx ;------------------------------------------- ; Convert Big-endian values to little endian ntohd [edx + TCP_header.SequenceNumber] ntohd [edx + TCP_header.AckNumber] ntohw [edx + TCP_header.Window] ntohw [edx + TCP_header.UrgentPointer] ;------------------------ ; Find 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) .findpcb: pusha mov ecx, socket_mutex call mutex_lock popa mov ebx, net_sockets mov si, [edx + TCP_header.DestinationPort] .socket_loop: mov ebx, [ebx + SOCKET.NextPtr] or ebx, ebx jz .no_socket ;respond_seg_reset cmp [ebx + SOCKET.Domain], AF_INET4 jne .socket_loop cmp [ebx + SOCKET.Protocol], IP_PROTO_TCP jne .socket_loop cmp [ebx + TCP_SOCKET.LocalPort], si jne .socket_loop mov eax, [ebx + IP_SOCKET.RemoteIP] cmp eax, [edi] ; Ipv4 source address je @f test eax, eax jnz .socket_loop @@: mov ax, [ebx + TCP_SOCKET.RemotePort] cmp [edx + TCP_header.SourcePort], ax je .found_socket test ax, ax jnz .socket_loop .found_socket: ; ebx now contains the socketpointer pusha mov ecx, socket_mutex call mutex_unlock popa DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: socket ptr=%x state=%u flags=%x\n", ebx, [ebx + TCP_SOCKET.t_state], [edx + TCP_header.Flags]:2 ;---------------------------- ; Check if socket isnt closed cmp [ebx + TCP_SOCKET.t_state], TCPS_CLOSED je .drop_no_socket ;---------------- ; Lock the socket pusha lea ecx, [ebx + SOCKET.mutex] call mutex_lock popa DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: socket locked\n" ;--------------------------- ; disable all temporary bits mov [ebx + TCP_SOCKET.temp_bits], 0 ;--------------------------------------- ; unscale the window into a 32 bit value movzx eax, [edx + TCP_header.Window] push ecx mov cl, [ebx + TCP_SOCKET.SND_SCALE] shl eax, cl mov dword [edx + TCP_header.Window], eax ; word after window is checksum, we dont need checksum anymore pop ecx ;--------------------------------------- ; Are we accepting incoming connections? test [ebx + SOCKET.options], SO_ACCEPTCON jz .no_accept DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Accepting new connection\n" pusha lea ecx, [ebx + SOCKET.mutex] call mutex_unlock popa push ecx edx esi edi ;;; call SOCKET_fork pop edi esi edx ecx test eax, eax jz .drop_no_socket mov ebx, eax mov [ebx + TCP_SOCKET.temp_bits], TCP_BIT_DROPSOCKET ;;; FIXME: should we take over bits from previous socket? push dword [edi + 4] ; Ipv4 destination addres pop [ebx + IP_SOCKET.LocalIP] push [edx + TCP_header.DestinationPort] pop [ebx + TCP_SOCKET.LocalPort] mov [ebx + TCP_SOCKET.t_state], TCPS_LISTEN .no_accept: ;------------------------------------- ; Reset idle timer and keepalive timer mov [ebx + TCP_SOCKET.t_idle], 0 mov [ebx + TCP_SOCKET.timer_keepalive], TCP_time_keep_idle or [ebx + TCP_SOCKET.timer_flags], timer_flag_keepalive ;-------------------- ; Process TCP options push ecx movzx ecx, [edx + TCP_header.DataOffset] cmp ecx, sizeof.TCP_header ; Does header contain any options? je .no_options DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Segment has options\n" ;;; FIXME: for LISTEN, options should be called after we determined route, we need it for MSS ;;; cmp [ebx + TCP_SOCKET.t_state], TCPS_LISTEN ; no options when in listen state ;;; jz .not_uni_xfer ; also no header prediction add ecx, edx lea esi, [edx + sizeof.TCP_header] .opt_loop: cmp esi, ecx ; are we scanning outside of header? jae .no_options lodsb cmp al, TCP_OPT_EOL ; end of option list? je .no_options cmp al, TCP_OPT_NOP je .opt_loop cmp al, TCP_OPT_MAXSEG je .opt_maxseg cmp al, TCP_OPT_WINDOW je .opt_window cmp al, TCP_OPT_SACK_PERMIT je .opt_sack_permit ; cmp al, TCP_OPT_SACK ; je .opt_sack cmp al, TCP_OPT_TIMESTAMP je .opt_timestamp DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: unknown option:%u\n", al jmp .no_options ; If we reach here, some unknown options were received, skip them all! .opt_maxseg: lodsb cmp al, 4 jne .no_options ; error occured, ignore all options! test [edx + TCP_header.Flags], TH_SYN jz @f lodsw rol ax, 8 DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Maxseg=%u\n", ax call TCP_mss @@: jmp .opt_loop .opt_window: lodsb cmp al, 3 jne .no_options test [edx + TCP_header.Flags], TH_SYN jz @f DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Got window scale option\n" or [ebx + TCP_SOCKET.t_flags], TF_RCVD_SCALE lodsb mov [ebx + TCP_SOCKET.SND_SCALE], al ;;;;; TODO @@: jmp .opt_loop .opt_sack_permit: lodsb cmp al, 2 jne .no_options test [edx + TCP_header.Flags], TH_SYN jz @f DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Selective Acknowledgement permitted\n" or [ebx + TCP_SOCKET.t_flags], TF_SACK_PERMIT @@: jmp .opt_loop .opt_timestamp: lodsb cmp al, 10 ; length must be 10 jne .no_options DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Got timestamp option\n" test [edx + TCP_header.Flags], TH_SYN jz @f or [ebx + TCP_SOCKET.t_flags], TF_RCVD_TSTMP @@: lodsd mov [ebx + TCP_SOCKET.ts_val], eax lodsd ; timestamp echo reply mov [ebx + TCP_SOCKET.ts_ecr], eax or [ebx + TCP_SOCKET.temp_bits], TCP_BIT_TIMESTAMP ; Since we have a timestamp, lets do the paws test right away! test [edx + TCP_header.Flags], TH_RST jnz .no_paws mov eax, [ebx + TCP_SOCKET.ts_recent] test eax, eax jz .no_paws cmp eax, [ebx + TCP_SOCKET.ts_val] jge .no_paws DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: PAWS: detected an old segment\n" mov eax, [esp+4+4] ; tcp_now sub eax, [ebx + TCP_SOCKET.ts_recent_age] pop ecx cmp eax, TCP_PAWS_IDLE jle .drop_after_ack ; TODO: update stats push ecx mov [ebx + TCP_SOCKET.ts_recent], 0 ; timestamp was invalid, fix it. .no_paws: jmp .opt_loop .no_options: pop ecx ;----------------------------------------------------------------------- ; 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 [ebx + TCP_SOCKET.t_state], TCPS_ESTABLISHED jnz .not_uni_xfer test [edx + TCP_header.Flags], TH_SYN + TH_FIN + TH_RST + TH_URG jnz .not_uni_xfer test [edx + TCP_header.Flags], TH_ACK jz .not_uni_xfer mov eax, [edx + TCP_header.SequenceNumber] cmp eax, [ebx + TCP_SOCKET.RCV_NXT] jne .not_uni_xfer mov eax, dword [edx + TCP_header.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 ;--------------------------------------- ; 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. test ecx, ecx jnz .not_sender ; - The congestion window is greater than or equal to the current send window. ; 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] jb .not_uni_xfer ; - The acknowledgment field in the segment is less than or equal to the maximum sequence number sent. mov eax, [edx + TCP_header.AckNumber] cmp eax, [ebx + TCP_SOCKET.SND_MAX] ja .not_uni_xfer ; - The acknowledgment field in the segment is greater than the largest unacknowledged sequence number. sub eax, [ebx + TCP_SOCKET.SND_UNA] jbe .not_uni_xfer DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Header prediction: we are sender\n" ;--------------------------------- ; Packet is a pure ACK, process it ; Delete acknowledged bytes from send buffer pusha mov ecx, eax lea eax, [ebx + STREAM_SOCKET.snd] call SOCKET_ring_free popa ; Update RTT estimators test [ebx + TCP_SOCKET.temp_bits], TCP_BIT_TIMESTAMP jz .no_timestamp_rtt mov eax, [esp + 4] ; timestamp when this segment was received sub eax, [ebx + TCP_SOCKET.ts_ecr] inc eax call TCP_xmit_timer jmp .rtt_done .no_timestamp_rtt: cmp [ebx + TCP_SOCKET.t_rtt], 0 je .rtt_done mov eax, [edx + TCP_header.AckNumber] cmp eax, [ebx + TCP_SOCKET.t_rtseq] jbe .rtt_done mov eax, [ebx + TCP_SOCKET.t_rtt] call TCP_xmit_timer .rtt_done: ; update window pointers mov eax, [edx + TCP_header.AckNumber] mov [ebx + TCP_SOCKET.SND_UNA], eax ; Stop retransmit timer and [ebx + TCP_SOCKET.timer_flags], not timer_flag_retransmission ; Unlock the socket pusha lea ecx, [ebx + SOCKET.mutex] call mutex_unlock popa ; Awaken waiting processes mov eax, ebx call SOCKET_notify ; Generate more output call TCP_output jmp .drop_no_socket ;------------------------------------------------- ; maybe we are the receiver in the uni-xfer then.. .not_sender: ; - The amount of data in the segment is greater than 0 (data count is in ecx) ; - The acknowledgment field equals the largest unacknowledged sequence number. This means no data is acknowledged by this segment. mov eax, [edx + TCP_header.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). ;;; TODO ; jnz .not_uni_xfer ; Complete processing of received data DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Header prediction: we are receiving %u bytes\n", ecx add [ebx + TCP_SOCKET.RCV_NXT], ecx ; Update sequence number with number of bytes we have copied movzx esi, [edx + TCP_header.DataOffset] add esi, edx lea eax, [ebx + STREAM_SOCKET.rcv] call SOCKET_ring_write ; Add the data to the socket buffer mov eax, ebx call SOCKET_notify or [ebx + TCP_SOCKET.t_flags], TF_DELACK ; Set delayed ack flag jmp .drop ;-------------------------------------------------- ; Header prediction failed, do it the slow way .not_uni_xfer: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Header prediction failed\n" ; Calculate receive window size push edx mov eax, SOCKETBUFFSIZE sub eax, [ebx + STREAM_SOCKET.rcv.size] mov edx, [ebx + TCP_SOCKET.RCV_ADV] sub edx, [ebx + TCP_SOCKET.RCV_NXT] cmp eax, edx jg @f mov eax, edx @@: DEBUGF DEBUG_NETWORK_VERBOSE, "Receive window size=%d\n", eax mov [ebx + TCP_SOCKET.RCV_WND], eax pop edx ; If we are in listen or syn_sent state, go to that specific code right away cmp [ebx + TCP_SOCKET.t_state], TCPS_LISTEN je .LISTEN cmp [ebx + TCP_SOCKET.t_state], TCPS_SYN_SENT je .SYN_SENT ;---------------------------- ; trim any data not in window ; check for duplicate data at beginning of segment (635) mov eax, [ebx + TCP_SOCKET.RCV_NXT] sub eax, [edx + TCP_header.SequenceNumber] jle .no_duplicate DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: %u bytes duplicate data!\n", eax test [edx + TCP_header.Flags], TH_SYN jz .no_dup_syn DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: got duplicate syn\n" and [edx + TCP_header.Flags], not (TH_SYN) inc [edx + TCP_header.SequenceNumber] cmp [edx + TCP_header.UrgentPointer], 1 jbe @f dec [edx + TCP_header.UrgentPointer] jmp .dup_syn @@: and [edx + TCP_header.Flags], not (TH_URG) .dup_syn: dec eax .no_dup_syn: ; Check for entire duplicate segment (646) cmp eax, ecx ; eax holds number of bytes to drop, ecx is data size jb .duplicate jnz @f test [edx + TCP_header.Flags], TH_FIN jnz .duplicate @@: ; Any valid FIN must be to the left of the window. ; At this point the FIN must be out of sequence or a duplicate, drop it and [edx + TCP_header.Flags], not TH_FIN ; send an ACK and resynchronize and drop any data. ; But keep on processing for RST or ACK DEBUGF DEBUG_NETWORK_VERBOSE, "616\n" or [ebx + TCP_SOCKET.t_flags], TF_ACKNOW mov eax, ecx ;TODO: update stats ;----------------------------------------------- ; Remove duplicate data and update urgent offset .duplicate: ;;; TODO: 677 add [edx + TCP_header.SequenceNumber], eax sub ecx, eax sub [edx + TCP_header.UrgentPointer], ax jg @f and [edx + TCP_header.Flags], not (TH_URG) mov [edx + TCP_header.UrgentPointer], 0 @@: ;-------------------------------------------------- ; Handle data that arrives after process terminates (687) .no_duplicate: cmp [ebx + SOCKET.PID], 0 jne .not_terminated cmp [ebx + TCP_SOCKET.t_state], TCPS_CLOSE_WAIT jbe .not_terminated test ecx, ecx jz .not_terminated mov eax, ebx call TCP_close ;;;TODO: update stats jmp .respond_seg_reset ;---------------------------------------- ; Remove data beyond right edge of window (700-736) .not_terminated: mov eax, [edx + TCP_header.SequenceNumber] add eax, ecx sub eax, [ebx + TCP_SOCKET.RCV_NXT] sub eax, [ebx + TCP_SOCKET.RCV_WND] ; eax now holds the number of bytes to drop jle .no_excess_data DEBUGF DEBUG_NETWORK_VERBOSE, "%d bytes beyond right edge of window\n", eax ;;; TODO: update stats cmp eax, ecx jl .dont_drop_all ; If a new connection request is received while in TIME_WAIT, drop the old connection and start over, ; if the sequence numbers are above the previous ones test [edx + TCP_header.Flags], TH_SYN jz .no_new_request cmp [ebx + TCP_SOCKET.t_state], TCPS_TIMED_WAIT jne .no_new_request ; mov edx, [ebx + TCP_SOCKET.RCV_NXT] ; cmp edx, [edx + TCP_header.SequenceNumber] ; add edx, 64000 ; TCP_ISSINCR FIXME mov eax, ebx call TCP_close jmp .findpcb ; FIXME: skip code for unscaling window, ... .no_new_request: ; If window is closed can only take segments at window edge, and have to drop data and PUSH from ; incoming segments. Continue processing, but remember to ACK. Otherwise drop segment and ACK cmp [ebx + TCP_SOCKET.RCV_WND], 0 jne .drop_after_ack mov eax, [edx + TCP_header.SequenceNumber] cmp eax, [ebx + TCP_SOCKET.RCV_NXT] jne .drop_after_ack DEBUGF DEBUG_NETWORK_VERBOSE, "690\n" or [ebx + TCP_SOCKET.t_flags], TF_ACKNOW ;;; TODO: update stats jmp .no_excess_data .dont_drop_all: ;;; TODO: update stats ;;; TODO: 733 sub ecx, eax and [ebx + TCP_SOCKET.t_flags], not (TH_PUSH or TH_FIN) .no_excess_data: ;----------------- ; Record timestamp (737-746) ; If last ACK falls within this segments sequence numbers, record its timestamp test [ebx + TCP_SOCKET.temp_bits], TCP_BIT_TIMESTAMP jz .no_timestamp mov eax, [ebx + TCP_SOCKET.last_ack_sent] sub eax, [edx + TCP_header.SequenceNumber] jb .no_timestamp test [ebx + TCP_header.Flags], TH_SYN or TH_FIN ; syn and fin occupy one byte jz @f dec eax @@: sub eax, ecx jae .no_timestamp DEBUGF DEBUG_NETWORK_VERBOSE, "Recording timestamp\n" mov eax, [esp + 4] ; tcp_now mov [ebx + TCP_SOCKET.ts_recent_age], eax mov eax, [ebx + TCP_SOCKET.ts_val] mov [ebx + TCP_SOCKET.ts_recent], eax .no_timestamp: ;------------------ ; Process RST flags test [edx + TCP_header.Flags], TH_RST jz .no_rst DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Got an RST flag\n" mov eax, [ebx + TCP_SOCKET.t_state] shl eax, 2 jmp dword [eax + .rst_sw_list] .rst_sw_list: dd .no_rst ; TCPS_CLOSED dd .no_rst ; TCPS_LISTEN dd .no_rst ; TCPS_SYN_SENT dd .econnrefused ; TCPS_SYN_RECEIVED dd .econnreset ; TCPS_ESTABLISHED dd .econnreset ; TCPS_CLOSE_WAIT dd .econnreset ; TCPS_FIN_WAIT_1 dd .rst_close ; TCPS_CLOSING dd .rst_close ; TCPS_LAST_ACK dd .econnreset ; TCPS_FIN_WAIT_2 dd .rst_close ; TCPS_TIMED_WAIT .econnrefused: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Connection refused\n" mov [ebx + SOCKET.errorcode], ECONNREFUSED jmp .close .econnreset: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Connection reset\n" mov [ebx + SOCKET.errorcode], ECONNRESET .close: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Closing connection\n" mov [ebx + TCP_SOCKET.t_state], TCPS_CLOSED ;;; TODO: update stats (tcp drops) mov eax, ebx call TCP_close jmp .drop_no_socket .rst_close: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Closing with reset\n" mov eax, ebx call TCP_close jmp .drop_no_socket .no_rst: ;-------------------------------------- ; handle SYN-full and ACK-less segments test [edx + TCP_header.Flags], TH_SYN jz .not_syn_full mov eax, ebx mov ebx, ECONNRESET call TCP_drop jmp .drop_with_reset .not_syn_full: ;--------------- ; ACK processing test [edx + TCP_header.Flags], TH_ACK jz .drop cmp [ebx + TCP_SOCKET.t_state], TCPS_SYN_RECEIVED jb .ack_processed ; states: closed, listen, syn_sent ja .no_syn_rcv ; established, fin_wait_1, fin_wait_2, close_wait, closing, last_ack, time_wait DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: state=syn_received\n" mov eax, [edx + TCP_header.AckNumber] cmp [ebx + TCP_SOCKET.SND_UNA], eax ja .drop_with_reset cmp eax, [ebx + TCP_SOCKET.SND_MAX] ja .drop_with_reset ;;; TODO: update stats mov eax, ebx call SOCKET_is_connected mov [ebx + TCP_SOCKET.t_state], TCPS_ESTABLISHED ; Do window scaling? test [ebx + TCP_SOCKET.t_flags], TF_RCVD_SCALE jz @f test [ebx + TCP_SOCKET.t_flags], TF_REQ_SCALE jz @f push word [ebx + TCP_SOCKET.requested_s_scale] ; Set send and receive scale factors to the received values pop word [ebx + TCP_SOCKET.SND_SCALE] @@: ;;; TODO: call TCP_reassemble mov eax, [edx + TCP_header.SequenceNumber] dec eax mov [ebx + TCP_SOCKET.SND_WL1], eax .no_syn_rcv: ;------------------------- ; check for duplicate ACKs mov eax, [edx + TCP_header.AckNumber] cmp eax, [ebx + TCP_SOCKET.SND_UNA] ja .not_dup_ack test ecx, ecx jnz .reset_dupacks mov eax, dword [edx + TCP_header.Window] cmp eax, [ebx + TCP_SOCKET.SND_WND] jne .reset_dupacks DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Processing duplicate ACK\n" ; If we have outstanding data, other than a window probe, this is a completely duplicate ACK ; (window info didnt change) The ACK is the biggest we've seen and we've seen exactly our rexmt threshold of them, ; assume a packet has been dropped and retransmit it. Kludge snd_nxt & the congestion window so we send only this one packet. test [ebx + TCP_SOCKET.timer_flags], timer_flag_retransmission jz @f mov eax, [edx + TCP_header.AckNumber] cmp eax, [ebx + TCP_SOCKET.SND_UNA] je .dup_ack @@: mov [ebx + TCP_SOCKET.t_dupacks], 0 jmp .not_dup_ack .dup_ack: inc [ebx + TCP_SOCKET.t_dupacks] cmp [ebx + TCP_SOCKET.t_dupacks], TCP_re_xmit_thresh jne .no_re_xmit push [ebx + TCP_SOCKET.SND_NXT] ; >>>> mov eax, [ebx + TCP_SOCKET.SND_WND] cmp eax, [ebx + TCP_SOCKET.SND_CWND] cmova eax, [ebx + TCP_SOCKET.SND_CWND] shr eax, 1 push edx xor edx, edx div [ebx + TCP_SOCKET.t_maxseg] cmp eax, 2 ja @f xor eax, eax mov al, 2 @@: mul [ebx + TCP_SOCKET.t_maxseg] pop edx mov [ebx + TCP_SOCKET.SND_SSTHRESH], eax and [ebx + TCP_SOCKET.timer_flags], not timer_flag_retransmission ; turn off retransmission timer mov [ebx + TCP_SOCKET.t_rtt], 0 mov eax, [edx + TCP_header.AckNumber] mov [ebx + TCP_SOCKET.SND_NXT], eax mov eax, [ebx + TCP_SOCKET.t_maxseg] mov [ebx + TCP_SOCKET.SND_CWND], eax ; Unlock the socket push ebx lea ecx, [ebx + SOCKET.mutex] call mutex_unlock ; retransmit missing segment mov eax, [esp] call TCP_output ; Lock the socket again mov ecx, [esp] add ecx, SOCKET.mutex call mutex_lock pop ebx ; Continue processing xor edx, edx mov eax, [ebx + TCP_SOCKET.t_maxseg] mul [ebx + TCP_SOCKET.t_dupacks] add eax, [ebx + TCP_SOCKET.SND_SSTHRESH] mov [ebx + TCP_SOCKET.SND_CWND], eax pop eax ; <<<< cmp eax, [ebx + TCP_SOCKET.SND_NXT] jb @f mov [ebx + TCP_SOCKET.SND_NXT], eax @@: jmp .drop .no_re_xmit: jbe .not_dup_ack DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Increasing congestion window\n" mov eax, [ebx + TCP_SOCKET.t_maxseg] add [ebx + TCP_SOCKET.SND_CWND], eax ; Unlock the socket push ebx lea ecx, [ebx + SOCKET.mutex] call mutex_unlock ; retransmit missing segment mov eax, [esp] call TCP_output ; Lock the socket again mov ecx, [esp] add ecx, SOCKET.mutex call mutex_lock pop ebx jmp .drop .not_dup_ack: ;------------------------------------------------- ; If the congestion window was inflated to account ; for the other side's cached packets, retract it mov eax, [ebx + TCP_SOCKET.SND_SSTHRESH] cmp eax, [ebx + TCP_SOCKET.SND_CWND] ja @f cmp [ebx + TCP_SOCKET.t_dupacks], TCP_re_xmit_thresh jbe @f mov [ebx + TCP_SOCKET.SND_CWND], eax @@: mov [ebx + TCP_SOCKET.t_dupacks], 0 mov eax, [edx + TCP_header.AckNumber] cmp eax, [ebx + TCP_SOCKET.SND_MAX] jbe @f ;;; TODO: update stats jmp .drop_after_ack @@: mov edi, [edx + TCP_header.AckNumber] sub edi, [ebx + TCP_SOCKET.SND_UNA] ; now we got the number of acked bytes in edi ;;; TODO: update stats DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: acceptable ACK for %u bytes\n", edi ;------------------------------------------ ; RTT measurements and retransmission timer (912-926) ; If we have a timestamp, update smoothed RTT test [ebx + TCP_SOCKET.temp_bits], TCP_BIT_TIMESTAMP jz .timestamp_not_present mov eax, [esp+4] sub eax, [ebx + TCP_SOCKET.ts_ecr] inc eax call TCP_xmit_timer jmp .rtt_done_ ; If no timestamp but transmit timer is running and timed sequence number was acked, ; update smoothed RTT. Since we now have an RTT measurement, cancel the timer backoff ; (Phil Karn's retransmit algo) ; Recompute the initial retransmit timer .timestamp_not_present: mov eax, [edx + TCP_header.AckNumber] cmp eax, [ebx + TCP_SOCKET.t_rtseq] jbe .rtt_done_ mov eax, [ebx + TCP_SOCKET.t_rtt] test eax, eax jz .rtt_done_ call TCP_xmit_timer .rtt_done_: ; If all outstanding data is acked, stop retransmit timer and remember to restart (more output or persist) ; If there is more data to be acked, restart retransmit timer, using current (possible backed-off) value. mov eax, [ebx + TCP_SOCKET.SND_MAX] cmp eax, [edx + TCP_header.AckNumber] jne .more_data and [ebx + TCP_SOCKET.timer_flags], not timer_flag_retransmission or [ebx + TCP_SOCKET.temp_bits], TCP_BIT_NEEDOUTPUT jmp .no_restart .more_data: test [ebx + TCP_SOCKET.timer_flags], timer_flag_persist jnz .no_restart mov eax, [ebx + TCP_SOCKET.t_rxtcur] mov [ebx + TCP_SOCKET.timer_retransmission], eax or [ebx + TCP_SOCKET.timer_flags], timer_flag_retransmission .no_restart: ;------------------------------------------- ; Open congestion window in response to ACKs mov esi, [ebx + TCP_SOCKET.SND_CWND] mov eax, [ebx + TCP_SOCKET.t_maxseg] cmp esi, [ebx + TCP_SOCKET.SND_SSTHRESH] jbe @f push edx push eax mul eax div esi pop edx shr edx, 3 add eax, edx pop edx @@: add esi, eax push ecx mov cl, [ebx + TCP_SOCKET.SND_SCALE] mov eax, TCP_max_win shl eax, cl pop ecx cmp esi, eax cmova esi, eax mov [ebx + TCP_SOCKET.SND_CWND], esi ;------------------------------------------ ; Remove acknowledged data from send buffer cmp edi, [ebx + STREAM_SOCKET.snd.size] jbe .finiacked push ecx edx ebx mov ecx, [ebx + STREAM_SOCKET.snd.size] lea eax, [ebx + STREAM_SOCKET.snd] sub [ebx + TCP_SOCKET.SND_WND], ecx call SOCKET_ring_free pop ebx edx ecx DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: our FIN is acked\n" stc jmp .wakeup .finiacked: push ecx edx ebx mov ecx, edi lea eax, [ebx + STREAM_SOCKET.snd] call SOCKET_ring_free pop ebx sub [ebx + TCP_SOCKET.SND_WND], ecx pop edx ecx DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: our FIN is not acked\n" clc ;---------------------------------------- ; Wake up process waiting on send buffer .wakeup: pushf ; Keep the flags (Carry flag) mov eax, ebx call SOCKET_notify ; Update TCPS mov eax, [edx + TCP_header.AckNumber] mov [ebx + TCP_SOCKET.SND_UNA], eax cmp eax, [ebx + TCP_SOCKET.SND_NXT] jb @f mov [ebx + TCP_SOCKET.SND_NXT], eax @@: popf ; General ACK handling complete ; Now do the state-specific ones ; Carry flag is set when our FIN is acked mov eax, [ebx + TCP_SOCKET.t_state] jmp dword [eax*4 + .ACK_sw_list] .ACK_sw_list: dd .ack_processed ; TCPS_CLOSED dd .ack_processed ; TCPS_LISTEN dd .ack_processed ; TCPS_SYN_SENT dd .ack_processed ; TCPS_SYN_RECEIVED dd .ack_processed ; TCPS_ESTABLISHED dd .ack_processed ; TCPS_CLOSE_WAIT dd .ack_fw1 ; TCPS_FIN_WAIT_1 dd .ack_c ; TCPS_CLOSING dd .ack_la ; TCPS_LAST_ACK dd .ack_processed ; TCPS_FIN_WAIT_2 dd .ack_tw ; TCPS_TIMED_WAIT .ack_fw1: jnc .ack_processed test [ebx + SOCKET.state], SS_CANTRCVMORE jnz @f mov eax, ebx call SOCKET_is_disconnected mov [ebx + TCP_SOCKET.timer_timed_wait], TCP_time_max_idle or [ebx + TCP_SOCKET.timer_flags], timer_flag_wait @@: mov [ebx + TCP_SOCKET.t_state], TCPS_FIN_WAIT_2 jmp .ack_processed .ack_c: jnc .ack_processed mov [ebx + TCP_SOCKET.t_state], TCPS_TIMED_WAIT mov eax, ebx call TCP_cancel_timers mov [ebx + TCP_SOCKET.timer_timed_wait], 2 * TCP_time_MSL or [ebx + TCP_SOCKET.timer_flags], timer_flag_wait mov eax, ebx call SOCKET_is_disconnected jmp .ack_processed .ack_la: jnc .ack_processed push ebx lea ecx, [ebx + SOCKET.mutex] call mutex_unlock pop ebx push ebx mov eax, ebx call TCP_disconnect pop ebx jmp .destroy_new_socket .ack_tw: mov [ebx + TCP_SOCKET.timer_timed_wait], 2 * TCP_time_MSL or [ebx + TCP_SOCKET.timer_flags], timer_flag_wait jmp .drop_after_ack .reset_dupacks: ; We got a new ACK, reset duplicate ACK counter mov [ebx + TCP_SOCKET.t_dupacks], 0 jmp .ack_processed ;------- ; LISTEN align 4 .LISTEN: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: state=listen\n" test [edx + TCP_header.Flags], TH_RST jnz .drop test [edx + TCP_header.Flags], TH_ACK jnz .drop_with_reset test [edx + TCP_header.Flags], TH_SYN jz .drop ;;; TODO: check if it's a broadcast or multicast, and drop if so push dword [edi] ; Ipv4 source addres pop [ebx + IP_SOCKET.RemoteIP] push [edx + TCP_header.SourcePort] pop [ebx + TCP_SOCKET.RemotePort] push [edx + TCP_header.SequenceNumber] pop [ebx + TCP_SOCKET.IRS] mov eax, [TCP_sequence_num] add [TCP_sequence_num], 64000 / 2 mov [ebx + TCP_SOCKET.ISS], eax mov [ebx + TCP_SOCKET.SND_NXT], eax TCP_sendseqinit ebx TCP_rcvseqinit ebx mov [ebx + TCP_SOCKET.t_state], TCPS_SYN_RECEIVED mov [ebx + TCP_SOCKET.t_flags], TF_ACKNOW mov [ebx + TCP_SOCKET.timer_keepalive], TCP_time_keep_interval ;;;; macro or [ebx + TCP_SOCKET.timer_flags], timer_flag_keepalive lea eax, [ebx + STREAM_SOCKET.snd] call SOCKET_ring_create lea eax, [ebx + STREAM_SOCKET.rcv] call SOCKET_ring_create and [ebx + TCP_SOCKET.temp_bits], not TCP_BIT_DROPSOCKET pusha mov eax, ebx call SOCKET_notify popa jmp .trim_then_step6 ;------------ ; Active Open align 4 .SYN_SENT: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: state=syn_sent\n" test [edx + TCP_header.Flags], TH_ACK jz @f mov eax, [edx + TCP_header.AckNumber] cmp eax, [ebx + TCP_SOCKET.ISS] jbe .drop_with_reset cmp eax, [ebx + TCP_SOCKET.SND_MAX] ja .drop_with_reset @@: test [edx + TCP_header.Flags], TH_RST jz @f test [edx + TCP_header.Flags], TH_ACK jz .drop mov eax, ebx mov ebx, ECONNREFUSED call TCP_drop jmp .drop @@: test [edx + TCP_header.Flags], TH_SYN jz .drop ; at this point, segment seems to be valid test [edx + TCP_header.Flags], TH_ACK jz .no_syn_ack ; now, process received SYN in response to an active open mov eax, [edx + TCP_header.AckNumber] mov [ebx + TCP_SOCKET.SND_UNA], eax cmp eax, [ebx + TCP_SOCKET.SND_NXT] jbe @f mov [ebx + TCP_SOCKET.SND_NXT], eax @@: .no_syn_ack: and [ebx + TCP_SOCKET.timer_flags], not timer_flag_retransmission ; disable retransmission timer push [edx + TCP_header.SequenceNumber] pop [ebx + TCP_SOCKET.IRS] TCP_rcvseqinit ebx or [ebx + TCP_SOCKET.t_flags], TF_ACKNOW mov eax, [ebx + TCP_SOCKET.SND_UNA] cmp eax, [ebx + TCP_SOCKET.ISS] jbe .simultaneous_open test [edx + TCP_header.Flags], TH_ACK jz .simultaneous_open DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: active open\n" ;;; TODO: update stats ; set socket state to connected push eax mov eax, ebx call SOCKET_is_connected pop eax mov [ebx + TCP_SOCKET.t_state], TCPS_ESTABLISHED ; Do window scaling on this connection ? mov eax, [ebx + TCP_SOCKET.t_flags] and eax, TF_REQ_SCALE or TF_RCVD_SCALE cmp eax, TF_REQ_SCALE or TF_RCVD_SCALE jne .no_scaling mov ax, word [ebx + TCP_SOCKET.requested_s_scale] mov word [ebx + TCP_SOCKET.SND_SCALE], ax .no_scaling: ;;; TODO: reassemble packets queue mov eax, [ebx + TCP_SOCKET.t_rtt] test eax, eax je .trim_then_step6 call TCP_xmit_timer jmp .trim_then_step6 .simultaneous_open: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: simultaneous open\n" ; We have received a syn but no ACK, so we are having a simultaneous open.. mov [ebx + TCP_SOCKET.t_state], TCPS_SYN_RECEIVED ;------------------------------------- ; Common processing for receipt of SYN .trim_then_step6: inc [edx + TCP_header.SequenceNumber] ;;; TODO: Drop any received data that follows receive window (590) mov eax, [edx + TCP_header.SequenceNumber] mov [ebx + TCP_SOCKET.RCV_UP], eax dec eax mov [ebx + TCP_SOCKET.SND_WL1], eax ;------- ; step 6 .ack_processed: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: ACK processed\n" ;---------------------------------------------- ; check if we need to update window information test [edx + TCP_header.Flags], TH_ACK jz .no_window_update mov eax, [ebx + TCP_SOCKET.SND_WL1] cmp eax, [edx + TCP_header.SequenceNumber] jb .update_window ja @f mov eax, [ebx + TCP_SOCKET.SND_WL2] cmp eax, [edx + TCP_header.AckNumber] jb .update_window ja .no_window_update @@: mov eax, dword [edx + TCP_header.Window] cmp eax, [ebx + TCP_SOCKET.SND_WND] jbe .no_window_update .update_window: ;;; TODO: update stats (Keep track of pure window updates) mov eax, dword [edx + TCP_header.Window] cmp eax, [ebx + TCP_SOCKET.max_sndwnd] jbe @f mov [ebx + TCP_SOCKET.max_sndwnd], eax @@: mov [ebx + TCP_SOCKET.SND_WND], eax DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Updating window to %u\n", eax push [edx + TCP_header.SequenceNumber] pop [ebx + TCP_SOCKET.SND_WL1] push [edx + TCP_header.AckNumber] pop [ebx + TCP_SOCKET.SND_WL2] or [ebx + TCP_SOCKET.temp_bits], TCP_BIT_NEEDOUTPUT .no_window_update: ;----------------- ; process URG flag test [edx + TCP_header.Flags], TH_URG jz .not_urgent cmp [edx + TCP_header.UrgentPointer], 0 jz .not_urgent cmp [ebx + TCP_SOCKET.t_state], TCPS_TIMED_WAIT je .not_urgent ; Ignore bogus urgent offsets movzx eax, [edx + TCP_header.UrgentPointer] add eax, [ebx + STREAM_SOCKET.rcv.size] cmp eax, SOCKET_MAXDATA jbe .not_urgent mov [edx + TCP_header.UrgentPointer], 0 and [edx + TCP_header.Flags], not (TH_URG) jmp .do_data .not_urgent: ; processing of received urgent pointer ;;; TODO (1051-1093) ;--------------------------------------- ; process the data in the segment (1094) .do_data: cmp [ebx + TCP_SOCKET.t_state], TCPS_TIMED_WAIT jae .final_processing test [edx + TCP_header.Flags], TH_FIN jnz @f test ecx, ecx jz .final_processing @@: ; The segment is in order? mov eax, [edx + TCP_header.SequenceNumber] cmp eax, [ebx + TCP_SOCKET.RCV_NXT] jne .out_of_order ; The reassembly queue is empty? cmp [ebx + TCP_SOCKET.seg_next], 0 jne .out_of_order ; The connection is established? cmp [ebx + TCP_SOCKET.t_state], TCPS_ESTABLISHED jne .out_of_order ; Ok, lets do this.. Set delayed ACK flag and copy data into socket buffer or [ebx + TCP_SOCKET.t_flags], TF_DELACK pusha movzx esi, [edx + TCP_header.DataOffset] add esi, edx lea eax, [ebx + STREAM_SOCKET.rcv] call SOCKET_ring_write ; Add the data to the socket buffer add [ebx + TCP_SOCKET.RCV_NXT], ecx ; Update sequence number with number of bytes we have copied popa ; Wake up the sleeping process mov eax, ebx call SOCKET_notify jmp .data_done .out_of_order: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP data is out of order\n" ; Uh-oh, some data is out of order, lets call TCP reassemble for help call TCP_reassemble DEBUGF DEBUG_NETWORK_VERBOSE, "1470\n" or [ebx + TCP_SOCKET.t_flags], TF_ACKNOW .data_done: ;--------------- ; FIN processing test [edx + TCP_header.Flags], TH_FIN jz .final_processing DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Processing FIN\n" cmp [ebx + TCP_SOCKET.t_state], TCPS_TIMED_WAIT jae .not_first_fin DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: First FIN for this connection\n" mov eax, ebx call SOCKET_cant_recv_more mov [ebx + TCP_SOCKET.t_flags], TF_ACKNOW inc [ebx + TCP_SOCKET.RCV_NXT] .not_first_fin: mov eax, [ebx + TCP_SOCKET.t_state] shl eax, 2 jmp dword [eax + .FIN_sw_list] .FIN_sw_list: dd .final_processing ; TCPS_CLOSED dd .final_processing ; TCPS_LISTEN dd .final_processing ; TCPS_SYN_SENT dd .fin_syn_est ; TCPS_SYN_RECEIVED dd .fin_syn_est ; TCPS_ESTABLISHED dd .final_processing ; TCPS_CLOSE_WAIT dd .fin_wait1 ; TCPS_FIN_WAIT_1 dd .final_processing ; TCPS_CLOSING dd .final_processing ; TCPS_LAST_ACK dd .fin_wait2 ; TCPS_FIN_WAIT_2 dd .fin_timed ; TCPS_TIMED_WAIT .fin_syn_est: mov [ebx + TCP_SOCKET.t_state], TCPS_CLOSE_WAIT jmp .final_processing .fin_wait1: mov [ebx + TCP_SOCKET.t_state], TCPS_CLOSING jmp .final_processing .fin_wait2: mov [ebx + TCP_SOCKET.t_state], TCPS_TIMED_WAIT mov eax, ebx call TCP_cancel_timers mov [ebx + TCP_SOCKET.timer_timed_wait], 2 * TCP_time_MSL or [ebx + TCP_SOCKET.timer_flags], timer_flag_wait call SOCKET_is_disconnected jmp .final_processing .fin_timed: mov [ebx + TCP_SOCKET.timer_timed_wait], 2 * TCP_time_MSL or [ebx + TCP_SOCKET.timer_flags], timer_flag_wait jmp .final_processing .drop_after_ack: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Drop after ACK\n" push edx ebx lea ecx, [ebx + SOCKET.mutex] call mutex_unlock pop eax edx test [edx + TCP_header.Flags], TH_RST jnz .dumpit or [eax + TCP_SOCKET.t_flags], TF_ACKNOW jmp .need_output .drop_with_reset: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Drop with reset\n" push ebx edx lea ecx, [ebx + SOCKET.mutex] call mutex_unlock pop edx ebx test [edx + TCP_header.Flags], TH_RST jnz .dumpit ;;; if its a multicast/broadcast, also drop test [edx + TCP_header.Flags], TH_ACK jnz .respond_ack test [edx + TCP_header.Flags], TH_SYN jnz .respond_syn jmp .dumpit ;----------------- ; Final processing .final_processing: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Final processing\n" push ebx lea ecx, [ebx + SOCKET.mutex] call mutex_unlock pop eax test [eax + TCP_SOCKET.temp_bits], TCP_BIT_NEEDOUTPUT jnz .need_output test [eax + TCP_SOCKET.t_flags], TF_ACKNOW jz .dumpit DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: ACK now!\n" .need_output: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: need output\n" call TCP_output .dumpit: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: dumping\n" call NET_packet_free add esp, 4 jmp .loop ;--------- ; Respond .respond_ack: push ebx mov cl, TH_RST call TCP_respond pop ebx jmp .destroy_new_socket .respond_syn: push ebx mov cl, TH_RST + TH_ACK call TCP_respond pop ebx jmp .destroy_new_socket .no_socket: pusha mov ecx, socket_mutex call mutex_unlock popa .respond_seg_reset: test [edx + TCP_header.Flags], TH_RST jnz .drop_no_socket ;;; TODO: if its a multicast/broadcast, also drop test [edx + TCP_header.Flags], TH_ACK jnz .respond_seg_ack test [edx + TCP_header.Flags], TH_SYN jnz .respond_seg_syn jmp .drop_no_socket .respond_seg_ack: mov cl, TH_RST call TCP_respond_segment jmp .drop_no_socket .respond_seg_syn: mov cl, TH_RST + TH_ACK call TCP_respond_segment jmp .drop_no_socket ;----- ; Drop .drop: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Dropping segment\n" pusha lea ecx, [ebx + SOCKET.mutex] call mutex_unlock popa .destroy_new_socket: test [ebx + TCP_SOCKET.temp_bits], TCP_BIT_DROPSOCKET jz .drop_no_socket mov eax, ebx call SOCKET_free .drop_no_socket: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_input: Drop (no socket)\n" call NET_packet_free add esp, 4 jmp .loop