| 0,0 → 1,202 |
|---|
| ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
| ;; ;; |
| ;; IP.INC ;; |
| ;; ;; |
| ;; IP 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 |
| ; |
| ; ip_rx processes all packets received by the network layer |
| ; It calls the appropriate protocol handler |
| ; |
| ; |
| ; |
| ;******************************************************************* |
| |
| |
| ;*************************************************************************** |
| ; Function |
| ; ip_rx |
| ; |
| ; Description |
| ; Handles received IP packets |
| ; This is a kernel function, called by stack_handler |
| ; |
| ;*************************************************************************** |
| ip_rx: |
| ; Look for a buffer to tx |
| mov eax, IPIN_QUEUE |
| call dequeue |
| cmp ax, NO_BUFFER |
| je ipr_exit ; Exit if no buffer available |
| |
| push eax |
| |
| ; convert buffer pointer eax to the absolute address |
| mov ecx, IPBUFFSIZE |
| mul ecx |
| add eax, IPbuffs |
| |
| mov edx, eax ; Save the address in edx for use by future processes |
| |
| ; Validate the IP checksum |
| mov ebx, edx |
| mov ah, [ebx + 10] |
| mov al, [ebx + 11] ; Get the checksum in intel format |
| mov [ebx + 10], word 0 ; clear checksum field - need to when |
| ; recalculating checksum |
| |
| ; this needs two data pointers and two size #. |
| ; 2nd pointer can be of length 0 |
| mov ebx, edx |
| mov [checkAdd1], ebx |
| mov [checkSize1], word 20 |
| mov [checkAdd2], dword 0 |
| mov [checkSize2], word 0 |
| |
| call checksum ; Recalculate IP checksum |
| cmp ax, [checkResult] |
| jnz ipr_dump |
| |
| ; If the IP address is 255.255.255.255, accept it |
| ; - it is a broadcast packet, which we need for dhcp |
| mov eax, [edx + 16] |
| cmp eax, 0xffffffff |
| je ipr_p0 |
| |
| ; Validate the IP address, if it isn't broadcast |
| cmp eax, [stack_ip] |
| jnz ipr_dump |
| |
| ipr_p0: |
| mov al, [edx] |
| and al, 0x0f |
| cmp al, 0x05 |
| jnz ipr_dump |
| |
| cmp [edx+8], byte 0 |
| jz ipr_dump |
| |
| mov ax, [edx + 6] |
| and ax, 0xFFBF |
| cmp ax, 0 |
| jnz ipr_dump |
| |
| ; Check the protocol, and call the appropriate handler |
| ; Each handler will re-use or free the queue buffer as appropriate |
| mov al, [edx + 9] |
| cmp al , PROTOCOL_ICMP |
| jnz ipr_p1 |
| pop eax |
| call icmp_rx |
| jmp ipr_exit |
| |
| ipr_p1: |
| cmp al , PROTOCOL_TCP |
| jnz ipr_p2 |
| pop eax |
| call tcp_rx |
| jmp ipr_exit |
| |
| ipr_p2: |
| cmp al , PROTOCOL_UDP |
| jnz ipr_dump |
| pop eax |
| call udp_rx |
| jmp ipr_exit |
| |
| ipr_dump: |
| ; No protocol handler available, so |
| ; silently dump the packet, freeing up the queue buffer |
| |
| ; inc dword [dumped_rx_count] |
| |
| pop eax |
| call freeBuff |
| |
| ipr_exit: |
| ret |
| |
| |
| |
| ;*************************************************************************** |
| ; Function |
| ; icmp_rx |
| ; |
| ; Description |
| ; ICMP protocol handler |
| ; This is a kernel function, called by ip_rx |
| ; edx contains the address of the buffer in use. |
| ; This buffer must be reused or marked as empty afterwards |
| ; |
| ;*************************************************************************** |
| icmp_rx: |
| cmp [edx + 20], byte 8 ; Is this an echo request? discard if not |
| jz icmp_echo |
| |
| call freeBuff |
| jmp icmp_exit |
| |
| icmp_echo: |
| push eax |
| mov [edx + 10], word 0 ; I think this was already done by IP rx |
| |
| ; swap the source and destination addresses |
| mov ecx, [edx + 16] |
| mov eax, [edx + 12] |
| mov [edx + 16], eax |
| mov [edx + 12], ecx |
| |
| ; recaluculate the IP header checksum |
| |
| mov ebx, edx |
| mov [checkAdd1], ebx |
| mov [checkSize1], word 20 |
| mov [checkAdd2], dword 0 |
| mov [checkSize2], word 0 |
| |
| call checksum |
| mov ax, [checkResult] |
| mov [edx + 10], ah |
| mov [edx + 11], al ; ?? correct byte order? |
| |
| mov [edx + 20], byte 0 ; change the request to a response |
| mov [edx + 22], word 0 ; clear ICMP checksum prior to re-calc |
| |
| ; Calculate the length of the ICMP data ( IP payload) |
| mov ah, [edx + 2] |
| mov al, [edx + 3] |
| sub ax, 20 |
| |
| mov [checkSize1], ax |
| mov ebx, edx |
| add ebx, 20 |
| |
| mov [checkAdd1], ebx |
| mov [checkAdd2], dword 0 |
| mov [checkSize2], word 0 |
| |
| call checksum |
| |
| mov ax, [checkResult] |
| mov [edx + 22], ah |
| mov [edx + 23], al |
| |
| ; Queue packet for transmission |
| |
| pop ebx |
| mov eax, NET1OUT_QUEUE |
| call queue |
| |
| icmp_exit: |
| ret |