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| ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
| ;; ;; |
| ;; UDP.INC ;; |
| ;; ;; |
| ;; UDP Processes for Menuet OS TCP/IP stack ;; |
| ;; ;; |
| ;; Version 0.3 29 August 2002 ;; |
| ;; ;; |
| ;; Copyright 2002 Mike Hibbett, mikeh@oceanfree.net ;; |
| ;; ;; |
| ;; See file COPYING for details ;; |
| ;; ;; |
| ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
| |
| |
| ;******************************************************************* |
| ; Interface |
| ; |
| ; udp_rx Handles received IP packets with the UDP protocol |
| ; |
| ;******************************************************************* |
| |
| |
| |
| |
| ;*************************************************************************** |
| ; Function |
| ; udp_rx |
| ; |
| ; Description |
| ; UDP protocol handler |
| ; This is a kernel function, called by ip_rx |
| ; IP buffer address given in edx |
| ; Free up (or re-use) IP buffer when finished |
| ; |
| ;*************************************************************************** |
| udp_rx: |
| push eax |
| |
| ; First validate the header & checksum. Discard buffer if error |
| |
| ; Look for a socket where |
| ; IP Packet UDP Destination Port = local Port |
| ; IP Packet SA = Remote IP |
| |
| movzx ebx, word [edx + 22] ; get the local port from |
| ; the IP packet's UDP header |
| mov eax, SOCKETBUFFSIZE * NUM_SOCKETS |
| mov ecx, NUM_SOCKETS |
| |
| fs1: |
| sub eax, SOCKETBUFFSIZE |
| cmp [eax + sockets + 12], bx ; bx will hold the 'wrong' value, |
| ; but the comparision is correct |
| loopnz fs1 ; Return back if no match |
| jz fs_done |
| |
| ; No match, so exit |
| jmp udprx_001 |
| |
| fs_done: |
| ; For dhcp, we must allow any remote server to respond. |
| ; I will accept the first incoming response to be the one |
| ; I bind to, if the socket is opened with a destination IP address of |
| ; 255.255.255.255 |
| mov ebx, [eax + sockets + 16] |
| cmp ebx, 0xffffffff |
| je udprx_002 |
| |
| mov ebx, [edx + 12] ; get the Source address from the IP packet |
| cmp [eax + sockets + 16], ebx |
| jne udprx_001 ; Quit if the source IP is not valid |
| |
| udprx_002: |
| ; OK - we have a valid UDP packet for this socket. |
| ; First, update the sockets remote port number with the incoming msg |
| ; - it will have changed |
| ; from the original ( 69 normally ) to allow further connects |
| movzx ebx, word [edx + 20] ; get the UDP source port |
| ; ( was 69, now new ) |
| mov [eax + sockets + 20], bx |
| |
| ; Now, copy data to socket. We have socket address as [eax + sockets]. |
| ; We have IP packet in edx |
| |
| ; get # of bytes in ecx |
| movzx ecx, byte [edx + 3] ; total length of IP packet. Subtract |
| mov ch, byte [edx + 2] ; 20 + 8 gives data length |
| sub ecx, 28 |
| |
| mov ebx, eax |
| add ebx, sockets ; ebx = address of actual socket |
| |
| mov eax, [ebx+ 4] ; get socket owner PID |
| push eax |
| |
| mov eax, [ebx + 24] ; get # of bytes already in buffer |
| add [ebx + 24], ecx ; increment the count of bytes in buffer |
| |
| ; point to the location to store the data |
| add ebx, eax |
| add ebx, SOCKETHEADERSIZE |
| |
| ; ebx = location for first byte, ecx has count, |
| ; edx points to data |
| |
| add edx, 28 ; edx now points to the data |
| mov edi, ebx |
| mov esi, edx |
| |
| cld |
| rep movsb ; copy the data across |
| |
| ; flag an event to the application |
| pop eax |
| mov ecx,1 |
| mov esi,0x3020+0x4 |
| |
| newsearch: |
| cmp [esi],eax |
| je foundPID |
| inc ecx |
| add esi,0x20 |
| cmp ecx,[0x3004] |
| jbe newsearch |
| |
| foundPID: |
| shl ecx,8 |
| or dword [ecx+0x80000+0xA8],dword 10000000b ; stack event |
| |
| mov [check_idle_semaphore],200 |
| |
| udprx_001: |
| pop eax |
| call freeBuff ; Discard the packet |
| ret |
| |