;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;; ;; 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 ;; ;; ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; $Revision$ ; IP underlying protocols numbers PROTOCOL_ICMP equ 1 PROTOCOL_TCP equ 6 PROTOCOL_UDP equ 17 struc IP_PACKET { .VersionAndIHL db ? ;+00 - Version[0-3 bits] and IHL(header length)[4-7 bits] .TypeOfService db ? ;+01 .TotalLength dw ? ;+02 .Identification dw ? ;+04 .FlagsAndFragmentOffset dw ? ;+06 - Flags[0-2] and FragmentOffset[3-15] .TimeToLive db ? ;+08 .Protocol db ? ;+09 .HeaderChecksum dw ? ;+10 .SourceAddress dd ? ;+12 .DestinationAddress dd ? ;+16 .DataOrOptional dd ? ;+20 } virtual at 0 IP_PACKET IP_PACKET end virtual ;******************************************************************* ; Interface ; ; ip_rx processes all packets received by the network layer ; It calls the appropriate protocol handler ; ; ; ;******************************************************************* ; ; IP Packet after reception - Normal IP packet format ; ; 0 1 2 3 ; 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 ; ; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ;0 |Version| IHL |Type of Service| Total Length | ; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ;4 | Identification |Flags| Fragment Offset | ; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ;8 | Time to Live | Protocol | Header Checksum | ; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ;12 | Source Address | ; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ;16 | Destination Address | ; +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ;20 | Data | ; +-+-+-.......... -+ ; ; ; [smb] attention! according to RFC 791 IP packet may have 'options' sections, ; so we can't simply think, that data have offset 20. We must calculate offset from ; IHL field ; macro GET_IHL reg, header_addr { movzx reg, byte [header_addr] ; we need 4-7 bits, so.... and reg, 0x0000000F ; IHL keeps number of octets, so we need to << 2 'reg' shl reg, 2 } include "tcp.inc" include "udp.inc" include "icmp.inc" ;*************************************************************************** ; Function ; ip_rx ; ; Description ; This is a kernel function, called by stack_handler ; Processes all IP-packets received by the network layer ; It calls the appropriate protocol handler ; ;*************************************************************************** proc ip_rx stdcall local buffer_number dd ? ; Look for a buffer to tx mov eax, IPIN_QUEUE call dequeue cmp ax, NO_BUFFER je .exit ; Exit if no buffer available mov [buffer_number], eax ;save buffer number ; convert buffer pointer eax to the absolute address imul eax, IPBUFFSIZE add eax, IPbuffs mov ebx, eax ; ebx=pointer to IP_PACKET ; DEBUGF 1, "K : ip_rx - proto: %u\n", [ebx + IP_PACKET.Protocol]:1 ; Validate the IP checksum mov dx, word[ebx + IP_PACKET.HeaderChecksum] xchg dh,dl ; Get the checksum in intel format mov [ebx + IP_PACKET.HeaderChecksum], 0 ; clear checksum field - need to when ; recalculating checksum ; this needs two data pointers and two size #. ; 2nd pointer can be of length 0 GET_IHL ecx, ebx + IP_PACKET.VersionAndIHL ;get packet length in ecx stdcall checksum_jb, ebx, ecx ;buf_ptr, buf_size cmp dx, ax ; DEBUGF 1, "K : ip_rx - checksums: %x - %x\n", dx, ax jnz .dump.1 ;if CHECKSUM isn't valid then dump packet mov edx, ebx ; EDX (IP-BUFFER POINTER) WILL BE USED FOR *_rx HANDLERS BELOW!!! ; DEBUGF 1, "K : ip_rx - dest: %x - %x\n", [ebx + IP_PACKET.DestinationAddress], [stack_ip] ; Validate the IP address, if it isn't broadcast mov eax, [stack_ip] cmp dword[ebx + IP_PACKET.DestinationAddress], eax je @f ; If the IP address is 255.255.255.255, accept it ; - it is a broadcast packet, which we need for dhcp mov eax, [ebx + IP_PACKET.DestinationAddress] cmp eax, 0xffffffff ;je @f ;mov ecx, [stack_ip] ;and eax, [subnet_mask] ;and ecx, [subnet_mask] ;cmp eax, ecx ;jne .dump.2 ;mov eax, [ebx + IP_PACKET.DestinationAddress] ;or eax, [subnet_mask] ;cmp eax, 0xffffffff jne .dump.2 @@: mov al, [ebx + IP_PACKET.VersionAndIHL] and al, 0x0f ;get IHL(header length) cmp al, 0x05 ;if IHL!= 5*4(20 bytes) ; DEBUGF 1, "K : ip_rx - ihl: %x - 05\n", al jnz .dump.3 ;then dump it ; DEBUGF 1, "K : ip_rx - ttl: %x - 00\n", [ebx + IP_PACKET.TimeToLive]:2 cmp [ebx + IP_PACKET.TimeToLive], 0 je .dump.4 ;if TTL==0 then dump it mov ax, [ebx + IP_PACKET.FlagsAndFragmentOffset] and ax, 0xFFBF ;get flags ; DEBUGF 1, "K : ip_rx - flags: %x - 0000\n", ax cmp ax, 0 ;if some flags was set then we dump this packet jnz .dump.5 ;the flags should be used for fragmented packets ; Check the protocol, and call the appropriate handler ; Each handler will re-use or free the queue buffer as appropriate mov al, [ebx + IP_PACKET.Protocol] cmp al , PROTOCOL_TCP jne .not_tcp ; DEBUGF 1,"K : ip_rx - TCP packet\n" mov eax, dword[buffer_number] call tcp_rx jmp .exit .not_tcp: cmp al, PROTOCOL_UDP jne .not_udp ; DEBUGF 1,"K : ip_rx - UDP packet\n" mov eax, dword[buffer_number] call udp_rx jmp .exit .not_udp: cmp al, PROTOCOL_ICMP jne .dump.6 ;protocol ain't supported ; DEBUGF 1,"K : ip_rx - ICMP packet\n" ;GET_IHL ecx, ebx + IP_PACKET.VersionAndIHL ;get packet length in ecx mov eax, dword[buffer_number] stdcall icmp_rx,eax,ebx,ecx ;buffer_number,IPPacketBase,IPHeaderLength jmp .exit .dump.1: DEBUGF 1, "K : ip_rx - dumped (checksum: 0x%x-0x%x)\n", dx, ax jmp .dump.x .dump.2: DEBUGF 1, "K : ip_rx - dumped (ip: %u.%u.%u.%u)\n", [ebx + IP_PACKET.DestinationAddress + 0]:1, [ebx + IP_PACKET.DestinationAddress + 1]:1, [ebx + IP_PACKET.DestinationAddress + 2]:1, [ebx + IP_PACKET.DestinationAddress + 3]:1 jmp .dump.x .dump.3: DEBUGF 1, "K : ip_rx - dumped (ihl: %u)\n", al jmp .dump.x .dump.4: DEBUGF 1, "K : ip_rx - dumped (ttl: %u)\n", [ebx + IP_PACKET.TimeToLive] jmp .dump.x .dump.5: DEBUGF 1, "K : ip_rx - dumped (flags: 0x%x)\n", ax jmp .dump.x .dump.6: DEBUGF 1, "K : ip_rx - dumped (proto: %u)\n", [ebx + IP_PACKET.Protocol]:1 .dump.x: inc dword[dumped_rx_count] mov eax, [buffer_number] call freeBuff .exit: ret endp