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Assembly Source File | 1992-05-17 | 53.4 KB | 2,314 lines

; ip.asm ;======================================================================== ; Copyright (C) 1991 by Jan.Engvald@ldc.lu.se, see file COPYING. ;************************************************************************ ;************************************************************************ ;* ;* UDP/IP library ;* ;* This library is in a transition phase from a PDCLKSET specific library ;* into a multiprocess, reentrant, any hardware type, general UDP/IP ;* library. The buffers used have a descriptor part and a packet part. ;* The descriptor part is used to allow reentrancy, different physical ;* address lengths and varying number of IP options. ;* ;* In this library DS:BX always points to the descriptor buffer, DS:DI ;* usually points to the physical header/IP header/UDP header part of ;* the IP packet buffer and DX,AX often contains an IP number in network ;* byte order (DL,DH,AL,AH). For efficiency reasons, IP numbers are ;* searched last half first (first halves are often equal). ;* ;* As this library is still evolving, you can not assume that it looks ;* the same in the next release. In particular, if you are using any of ;* of the subroutines, check if their calls or results have been changed. ;* ;* The current implementation is RFC791 (IP) and RFC1122 (host requirements) ;* compliant, except for a few cases: I havn't found a reasonable solution ;* on how to report back to the application ICMP errors like parameter ;* problem, protocol and port unreachables, and fragment reassembly time ;* exceeded. Also, IP options are allowed, but the interpretation and handling ;* must be done by the application. Apart from the above, it is a de luxe ;* implementation that includes things like multiple default gateways, ;* sending protocol and port unreachables, IP type of service handling (not ;* tested), fragment reassembly and source quench introduced delay. ;* ;************************************************************************ ;************************************************************************ ; send errors: SERRUNREACH equ 0 ; host or net unreachable SERRNOBUF equ 2 ; temporary out of buffers SERRNOARP equ 4 ; got no ARP reply SERRTIMOUT equ 6 ; general timeout SERRNOTRAF equ 8 ; received no traffic from dst ICMP_PROT equ 1 ; Internet Control Msg Prot UDP_PROT equ 17 ; IP protocol type UDP Descriptor struc dLink LinkStruc <> ; next & prev links ; dIOCB iocb <> ; pkt drvr hi perf struc dPtrPhys dw 0 ; ptr to physical hdr dPtrIp dw 0 ; ptr to IP hdr dPtrUdp dw 0 ; ptr to UDP hdr dPktLen dw 0 ; packet length (bytes) dPktEnd dw 0 ; end of packet dTimOut2Msg equ dPktEnd ; Timeout msg for findsends dSqDelay dw 0 ; source quench delay (ms) dWaitEvent dw 0 ; event to wait for dPtrFrag equ dWaitEvent ; ptr to defargment listhead dTimOutMsg dw 0 ; to be displayed at timeout dTickResend dw 1*18 ; resend start interval (ticks) dTickTimeout dw 4*18 ; timeout ticks (in 1/18 s) dTick2Timeout dw 14*18 ; second timeout dIdxHwDst equ dSqDelay ; arp table index for hw dst dIdxIpDst equ dTick2Timeout ; arp table index for IP dst dAdjust equ (4-(($-dLink) and 3)) and 3 if dAdjust db dAdjust dup (0) endif dGwys2Chk db 0 ; # of untried gateways dSnap db 0 ; 802.3 snaps used dPtrDes dw 0 ; ptr to start of descriptor dHwDst equ $-dLink ; (part of pd packet) DESCRLEN equ $-dLink Descriptor ends HwStruc struc hEthDst db 6 dup (0) ; Ethernet destination address hEthSrc db 6 dup (0) ; my Ether addr hProtType dw 0008 ; 0800 = IP HWHDRLEN equ $-hEthDst HwStruc ends SnapStruc struc sDSAP db 170 sSSAP db 170 sContr db 3 sOrgCode db 0,0,0 sProt db 08, 00 SNAPLEN equ $-sDSAP SnapStruc ends IpStruc struc iIpVerHlen db 45h ; ver 4, 5 32-bit hdr words iIpTos db 0 ; type of service iIpLen dw 0 ; IP packet length iIpId dw 0100h ; id 0001 iIpFlFrag dw 0 ; no flags or fragments iIpTtl db 90 ; time to live iIpProt db 0 ; 17 = udp iIpXsum dw 0 ; header checksum iIpSrc dw 0, 0 ; Don't know my IP nmbr iIpDst dw 0ffffh, 0ffffh ; local net broadcast IP iIpOptions equ $-iIpVerHlen IPHDRLEN equ $-iIpVerHlen IpStruc ends UdpStruc struc uUdpSrc dw 4400h ; source port 44h = 68 uUdpDst dw 4300h ; dest port 43h = 67 uUdpLen dw 0 ; length in bytes uUdpXsum dw 0 ; udp checksum uUdpData equ $-uUdpSrc UDPHDRLEN equ $-uUdpSrc UdpStruc ends BootpStruc struc uUdpStruc UdpStruc <> uBotOp db 1 ; bootp request uBotHtype db 0 ; hardware type uBotHlen db 0 ; hardware addr lenght uBotHops db 0 ; hops uBotXid dw 0, 0 ; transaction id uBotSecs dw 0001 ; 0100h seconds since boot uBotUnused dw 0 ; not defined uBotCliIp dw 0, 0 ; Client IP unknown uBotYourIp dw 0, 0 ; my IP yet unknown uBotServIp dw 0, 0 ; Server IP uBotGwyIp dw 0, 0 ; Gateway IP uBotCliHwAd db 16 dup (0) ; My Hardware address uBotSname db 64 dup (0) ; server name uBotFilNam db 128 dup (0) ; file name uBotMagNum dw 8263h, 6353h ; Magic number uBotVend db 64-4 dup (0) ; Vendor specific area BpDataLen = $-uBotOp BootpStruc ends IcmpStruc struc uIcmpTypecode dw 0 uIcmpXsum dw 0 uIcmpData dw 0, 0 uIcmpIpHdr dw iIpOptions+4 dup (0) ICMPHDRLEN equ uIcmpIpHdr-uIcmpTypecode IcmpStruc ends BootpFrame struc fDescriptor Descriptor <> fHwStruc HwStruc <> fIpStruc IpStruc <> fBotStruc BootpStruc <> BpLen = $-fHwStruc BootpFrame ends even Events dw 1 ; =1 so DONT_WAIT always true DONT_WAIT equ 1 GOT_BOOTP equ 2 GOT_ARPREPLY equ 4 GOT_TIMEREPLY equ 8 GOT_ARPREQ equ 16 GOT_ICMPMSG equ 32 GOT_NSREPLY equ 64 GenFlags dw 0 ARGZONE equ 2 ARGZONESPEC equ 4 DSTNOW equ 8 IS_386 equ 16 TBL_READY equ 32 DBGINTERR equ 08000h MySegm dw 0 Hlen dw 0 H2Len dw 0 MyMask dw 2 dup (0h) MyNet dw 2 dup (0h) IpHandle dw 0 IpIdCounter dw 0 InSendAndW dw 0 ifndef MAXDEFGWYS MAXDEFGWYS equ 4 endif DefGwyIndex dw 0 DefGwyNum dw 0 DefGwys dw MAXDEFGWYS*2 dup (0) if TBLBUILD or PINGCLIENT DefNSnum dw 0 DefNS dw MAXDEFNS*2 dup (0) endif ; TBLBUILD or PINGCLIENT ifndef ROUTESLOTS ROUTESLOTS equ 8 endif ; The route table contains information on hosts behind gateways. ; ; If we don't receive anything from an IP number within one minute after we ; last sent to it, we return SERRNOTRAF on the next send. This is cleared ; after another minute. RouteTabIpD2 dw ROUTESLOTS dup (0) ; destination IP # RouteTabIpD1 dw ROUTESLOTS dup (0) RouteTabTos dw ROUTESLOTS dup (0) ; type of service RouteTabIpG2 dw ROUTESLOTS dup (0) ; gateway IP # RouteTabIpG1 dw ROUTESLOTS dup (0) RouteTabTrTx dw ROUTESLOTS dup (0) ; transmitt timer RouteTabTrRx dw ROUTESLOTS dup (0) ; receive timer RouteTabFlags dw ROUTESLOTS dup (0) ; flags (must follow TrRx) RouteTabTrSq dw ROUTESLOTS dup (0) ; source quench timer RouteTabSqDelay dw ROUTESLOTS dup (0) ; source quench delay RouteTabUnreach dw ROUTESLOTS dup (0) ; destination unreachable RoutePutSlot dw 0 IpDesBuf BootpFrame <> SnapHdr SnapStruc <> IpHdr equ IpDesBuf.fIpStruc MyIpNr equ IpDesBuf.fIpStruc.iIpSrc ;************************************************************************ ;* SendUdpFind ;* ;* Input: BX = IP description buffer ptr (BX saved) ;* DX = addr of length prepended IP list to send to until reply ;* Output: Zero and CX = 0 if OK ;* non-zero and CX = errorcode if error ;* Destroys: AX, CX, DX, SI, DI, ES and flags ;************************************************************************ SendUdpFind proc near mov [bx].dTimoutMsg,0 ; continue even if no reply mov ah,2 ; do 2 turns over all IP #s Send2ndTurn: mov si,dx ; get IP list addr lodsb ; # of IP numbers to al inc si SendNextIP: mov di,[bx].dPtrIp lea di,[di].iIpDst movsw ; put next IP number movsw cmp ax,0101h ; last IP last turn? jne Send2orMore mov di,[bx].dTimOut2Msg mov [bx].dTimoutMsg,di ; -yes, terminate if no reply Send2orMore: push ax push dx push si mov ax,[bx].dPktLen call SendUdpPkt ; send udp packet pop si pop dx pop ax jz SendUdpFindRet ; done if reply dec al jnz SendNextIP ; more IP numbers this turn? mov di,[bx].dTick2Timeout ; -no, use longer timeout mov [bx].dTickTimeout,di ; for 2nd turn dec ah jnz Send2ndTurn ; both turns done? or cx,cx SendUdpFindRet: ret SendUdpFind endp ;************************************************************************ ;* SendUdpPkt ;* ;* Input: AX = IP data byte length (AX destroyed) ;* BX = IP description buffer ptr (BX saved) ;* Output: Zero and CX = 0 if OK ;* non-zero and CX = errorcode if error ;* Destroys: AX, CX, DX, SI, DI, ES and flags ;************************************************************************ SendUdpPkt proc near push ax xchg ah,al mov di,[bx].dPtrUdp mov [di].uUdpLen,ax ; fill in UDP total length mov [di].uUdpXsum,ax ; ensure chksum is calculated mov di,[bx].dPtrIp mov [di].iIpProt,UDP_PROT ; set UDP protocol call UdpChkSum ; calculate UDP checksum pop ax call SendIpPkt ; send UDP packet ret SendUdpPkt endp ;************************************************************************ ;* SendIcmpPkt ;* ;* Input: BX = IP description buffer ptr (BX saved) ;* CX = IP data length ;* Output: Zero and CX = 0 if OK ;* non-zero and CX = errorcode if error ;* Destroys: AX, CX, DX, SI, DI, ES and flags ;************************************************************************ SendIcmpPkt proc near push cx ; save length call IcmpChkSum ; calculate icmp checksum mov [bx].dWaitEvent,0 ; don't wait for answer mov di,[bx].dPtrIp mov [di].iIpProt,ICMP_PROT pop ax ; restore length ; call SendIpPkt ; ret SendIcmpPkt endp ;************************************************************************ ;* SendIpPkt ;* ;* Input: AX = IP data byte length (AX destroyed) ;* BX = IP description buffer ptr (BX saved) ;* Output: Zero and CX = 0 if OK ;* non-zero and CX = errorcode if error ;* Destroys: AX, CX, DX, SI, DI, ES and flags ;************************************************************************ SendIpPkt proc near call IPHdrLength ; calculate IP hdr length mov dx,MyIpNr ; my IP # to IP src mov [si].iIpSrc,dx mov dx,MyIpNr+2 mov [si].iIpSrc+2,dx add ax,cx ; add hdr length to data length mov [bx].dPktLen,ax ; and save it xchg ah,al mov [si].iIpLen,ax ; fill in IP length mov dx,IpIdCounter mov [si].iIpId,dx ; unique id for frag reassembly inc dx mov IpIdCounter,dx call IpChkSum ; calculate checksum if RFCC call Ageing ; clear unused table slots endif ; RFCC call PutPhysDst ; do we have HW dest addr? jnz SendIpRet ; -no, ARP timed out call PutPhysSrc ; put my HW src addr add [bx].dPktLen,cx ; pkt length (HW addr part) jmp short SendAndWait ; -yes, send packet SendIpRet: ret SendIpPkt endp ;************************************************************************ ;* SendAndWait ;* Input: BX = description buffer ptr (saved) ;* Output: Zero and CX = 0 if OK ;* non-zero and CX = errorcode if error ;* Destroys: AX, CX, DX, SI, DI, ES, flags ;************************************************************************ SendAndWait proc near inc InSendAndW mov si,[bx].dWaitEvent ; event to wait for or si,si ; no event to wait for? jz SendDontWait not si and Events,si ; clear this event bit SendDontWait: not si if RFCC ; Do RFC1016 Source Quench Introduced Delay mov ax,[bx].dSqDelay ; SQ delay (ms) add ax,32 ; round up mov cl,6 shr ax,cl ; convert ms to ticks call CurrentTicks add ax,cx ; time to send at SendSqLoop: call CurrentTicks cmp cx,ax ; can we send it now? jns SendNoSqDelay call Something2Do ; - no, wait a while jmp short SendSqLoop SendNoSqDelay: else call CurrentTicks endif ; RFCC call SendRawPkt ; send packet part of buffer mov di,[bx].dTickResend ; first resend time mov ax,cx add ax,di mov dx,cx add dx,[bx].dTickTimeout ; time out time WaitLoop: test Events,si ; got what we want? jz SendChk SendWaitOK: xor cx,cx SendWaitRet: dec InSendAndW or cx,cx ret SendChk: call Something2Do ; anything else to do? ChkTimeout: call CurrentTicks cmp cx,dx ; time out? jns SendTimedout cmp cx,ax ; time to resend? js WaitLoop shl di,1 ; double resend time cmp di,30*18 jbe SendDouble mov di,30*18 ; max 30 seconds SendDouble: add ax,di ; next resend time call SendRawPkt ; send same packet again jmp short WaitLoop SendTimedout: mov dx,[bx].dTimOutMsg mov cx,SERRTIMOUT or dx,dx ; if no timeout msg jz SendWaitRet ; just return mov ah,9 ; print error msg in dx int 21h mov al,04 ; error code 4 call Terminate SendAndWait endp ;************************************************************************ ;* SendRawPkt ;* Input: BX = description buffer ptr (saved) ;* Destroys: flags ;* ;* (The saving of all registers below is not needed for the Crynwr ;* collection of packet drivers, but as far as I understand the packet ;* driver specification other drivers may need it.) ;************************************************************************ SendRawPkt proc near push dx push cx push bx push ax push si push di push bp push es mov si,[bx].dPtrPhys ; get start of packet mov cx,[bx].dPktLen ; and its length mov ah,4 ; send packet to push ds ; packet driver int_pkt pop ds pop es pop bp pop di pop si pop ax pop bx pop cx jc BadPkt ; any errors? pop dx ret BadPkt: call print_error ; display explanation mov al,03 ; error code 3 call Terminate SendRawPkt endp ;************************************************************************ ;* PutPhysSrc ;* ;* Input: BX = IP description buffer ptr (saved) ;* Output: HW src addr and IP prot type put into pkt ;* CX = phys header length ;* Destroys: CX, SI, DI, ES, flags ;************************************************************************ PutPhysSrc proc near mov si,offset MyHwAd ; get my HW addr from ARP buf mov di,[bx].dPtrPhys mov cx,Hlen add di,cx push cs pop es rep movsb ; put my HW addr as src HW addr test [bx].dSnap,1 jz PutPhysNotSnap mov cx,[bx].dPktLen add cx,8 xchg ch,cl mov [di],cx add di,2 mov cx,sProt-sDSAP mov si,offset SnapHdr rep movsb PutPhysNotSnap: mov cx,di sub cx,[bx].dPtrPhys add cx,2 ; physical header length mov word ptr [di],0008h ; protocol type IP (0800) ret PutPhysSrc endp ;************************************************************************ ;* PutPhysDst ;* ;* Input: BX = IP description buffer ptr (saved) ;* Output: Zero and CX = 0 if OK ;* non-zero and CX = errorcode if error ;* Destroys: AX, CX, DX, SI, DI, ES, flags ;************************************************************************ PutPhysDst proc near mov ax,DefGwyNum ; # of default gwys we have mov [bx].dGwys2Chk,al ; gwys still left to check PutPhysAgain: mov di,[bx].dPtrIp mov al,[di].iIpTos ; get type of service xor ah,ah mov si,ax mov dx,[di].iIpDst ; set dx,ax = dst IP # mov ax,[di].iIpDst+2 call ArpPutHwDst ; do we know dst phys addr? jz FoundArpEntry ; - yes, copied hw addr call MyNetChk ; - no. Is dst on my net? jz PutMynetArp ; - yes, don't use gwy ; and ARP dst call UseGwy ; - no, use a gateway jcxz PutArp ; destination unreachable? jmp short PutPhysRet PutMynetArp: mov [bx].dGwys2Chk,1 PutArp: call ArpPutHwDst ; have hw addr for this IP # ? jz FoundArpEntry ; - yes, copied hw addr to pkt call SendArpReq ; - no, arp for it jz PutPhysAgain ; if reply, put in hw addr call SwitchGwy ; else try next gwy mov cx,SERRNOARP dec [bx].dGwys2Chk ; any more default gwys? jnz PutPhysAgain PutPhysRet: or cx,cx FoundArpEntry: ret PutPhysDst endp ;************************************************************************ ;* RouteFind ;* ;* Input: DX = first word of dst IP # (saved if not found) ;* AX = second word of dst IP # (saved if not found) ;* SI = IP type of service ;* Output: if found: zero and DI = route table index ;* DX = first word of gwy IP # ;* AX = second word of gwy IP # ;* CX = net/host unreachable code ;* Destroys: CX, DI, ES, flags ;************************************************************************ RouteFind proc near mov di,offset RouteTabIpD2 mov cx,ROUTESLOTS or cx,cx ; ensure non-zero flag PushfDI RouteFindNext: ; look for matching slot repne scasw jnz RouteFindRet cmp dx,2*RouteSLOTS-2[di] ; does dst IP first part match? jne RouteFindNext ; - no, look further cmp si,4*RouteSLOTS-2[di] ; does dst tos match? jne RouteFindNext ; - no, look further sub di,offset RouteTabIpD2+2 ;- yes, compute slot index mov dx,RouteTabIpG1[di] ; get gwy IP # mov ax,RouteTabIpG2[di] ; mov cx,RouteTabUnreach[di] ; get unreachable code PopfEI cmp di,di ; set zero flag ret ; zero (found) return RouteFindRet: PopfEI ret ; non zero (not found) return RouteFind endp ;************************************************************************ ;* MyNetChk ;* ;* Input: DX = first word of IP # (saved) ;* AX = second word of IP # (saved) ;* Output: zero if same net else non-zero ;* Destroys: flags ;************************************************************************ MyNetChk proc near push ax push dx and dx,MyMask ; check if my net cmp dx,MyNet jne MyNetRet and ax,MyMask+2 cmp ax,MyNet+2 MyNetRet: pop dx pop ax ret MyNetChk endp ;************************************************************************ ;* UseGwy ;* ;* Input: DX = first word of destination IP # ;* AX = second word of destination IP # ;* SI = IP type of service ;* Output: DX = first word of gateway IP # ;* AX = second part of gateway IP # ;* CX = net/host unreachable code ;* Destroys: CX, SI, DI, ES, flags ;************************************************************************ UseGwy proc near PushfDI call RouteFind ; is dst in route tbl? jz short UseGwyKnown ; - yes, have gwy IP # ; - no, use default gwy dec cx cmp dl,127 ; don't send to 127.x.x.x je UseGwyRet mov di,RoutePutSlot add di,2 ; advance index two bytes cmp di,ROUTESLOTS*2 ; at end of table? jb UseRouteSlot xor di,di ; - yes, wrap around UseRouteSlot: mov RoutePutSlot,di mov RouteTabIpD1[di],dx ; put destination IP # mov RouteTabIpD2[di],ax mov RouteTabTos[di],si mov si,DefGwyIndex shl si,1 shl si,1 mov dx,DefGwys[si] mov ax,DefGwys+2[si] mov RouteTabIpG1[di],dx ; and default gwy IP # mov RouteTabIpG2[di],ax ; into route table call CurrentTicks mov RouteTabTrRx[di],cx ; put current time xor cx,cx ; initialize other fields mov RouteTabUnreach[di],cx ; clear unreachable mov RouteTabFlags[di],cx mov RouteTabSqDelay[di],cx or si,dx or si,ax ; any non-zero gwy IP #? jz UseGwyNone ; - yes UseGwyKnown: if RFCC push cx push ax call CurrentTicks mov RouteTabTrTx[di],cx ; transmit time mov ax,RouteTabSqDelay[di] ; move sq delay to descriptor mov [bx].dSqDelay,ax dec ax ; any delay? js UseNoSqDelay mov ax,RouteTabTrSq[di] ; - yes add ax,18 ; has one second passed cmp ax,cx ; since we last decremented jns UseNoSqDelay ; the delay value? mov RouteTabTrSq[di],cx dec RouteTabSqDelay[di] ; - yes, one millisecond off UseNoSqDelay: pop ax pop cx endif ; RFCC UsegwyRet: PopfEI ret UseGwyNone: PopfEI mov dx,offset NoGwyMsg mov ah,9 ; - no, print error msg in dx int 21h mov al,08 ; error code 8 call Terminate UseGwy endp ;************************************************************************ ;* SwitchGwy ;* ;* Input: DX = first word of gateway IP # (saved) ;* AX = second word of gateway IP # (saved) ;* Destroys: CX, DI, ES, flags ;************************************************************************ SwitchGwy proc near PushfDI mov di,DefGwyIndex ; if current default gateway shl di,1 shl di,1 cmp dx,DefGwys[di] ; is the one jne SwitchNotThis cmp ax,DefGwys+2[di] ; that failed jne SwitchNotThis shr di,1 shr di,1 inc di ; then switch to cmp di,DefGwyNum jb SwitchNextGwy xor di,di SwitchNextGwy: mov DefGwyIndex,di ; next default gateway SwitchNotThis: PopfEI mov di,offset RouteTabIpG2 ; remove failing gateway mov cx,ROUTESLOTS ; from all route slots PushfDI SwitchRouteNext: ; look for matching slot repne scasw jnz SwitchGwyRet ; all entries searched cmp dx,2*ROUTESLOTS-2[di] ; does gwy IP 2nd part match? jne SwitchRouteNext ; - no, look further sub di,offset RouteTabIpG2+2 ;- yes, clear this route mov RouteTabIpD1[di],0 mov RouteTabIpD2[di],0 mov RouteTabIpG1[di],0 mov RouteTabIpG2[di],0 add di,offset RouteTabIpG2+2 jmp short SwitchRouteNext ; more routes using this gwy? SwitchGwyRet: PopfEI ret SwitchGwy endp ;************************************************************************ ;* ChkSum ;* Input: SI = start addr ;* CX = # of bytes ;* Output: AX = 1-complement checksum ;* CX = partial checksum ;* SI = addr of next byte ;* Destroys: Flags ;************************************************************************ ChkSum proc near if PINGCLIENT test GenFlags,IS_386 jz ChkSum8086 .386 push edx ; save 386 registers push eax shr cx,1 ; divide by two, round down pushf ; keep odd bit in carry shr cx,1 pushf xor edx,edx ; clear edx and carry ChkLoop386: lodsd adc edx,eax ; add to previous running sum loopw ChkLoop386 adc edx,0 ; add the last carry in again mov eax,edx shr eax,16 add dx,ax adc dx,0 popf ; odd # of words? jnc NotOddWords lodsw add dx,ax adc dx,0 NotOddWords: popf ; odd # of bytes? jnc NotOddBytes lodsb ; get that last byte xor ah,ah ; clear carry and the high portion add dx,ax ; add the last one in adc dx,0 ; add the carry in, too NotOddBytes: pop eax mov ax,dx mov cx,dx pop edx not ax ; take one more 1-complement ret .8086 endif ; PINGCLIENT ChkSum8086: push dx shr cx,1 ; divide by two, round down pushf ; keep odd bit in carry xor dx,dx ; clear dx and carry ChkLoop: lodsw adc dx,ax ; add to previous running sum loop ChkLoop adc dx,0 ; add the last carry in again popf ; odd # of bytes? jnc NotOdd lodsb ; get that last byte xor ah,ah ; clear carry and the high portion add dx,ax ; add the last one in adc dx,0 ; add the carry in, too NotOdd: mov ax,dx mov cx,dx pop dx not ax ; take one more 1-complement ret ChkSum endp ;************************************************************************ ;* UdpChkSum (both for generate and check!) ;* ;* Input: BX = IP description buffer ptr (saved) ;* Output: Zero if OK; checksum filled in ;* SI = addr of next byte ;* DI = IP Ptr ;* Destroys: AX, CX, DX, SI, DI, flags ;************************************************************************ UdpChkSum proc near mov si,[bx].dPtrIp mov di,[bx].dPtrUdp xor cx,cx ; save ttl for pseudo hdr xchg cl,[si].iIpTtl ; usage push cx xor dx,dx xchg dx,[di].uUdpXsum ; save and clear checksum mov cx,[di].uUdpLen ; save UDP length mov [si].iIpXsum,cx xchg ch,cl mov ax,di add ax,cx or dx,dx ; is there a checksum? mov si,ax ; - no, not available/wanted jz UdpNoSum ; but set si to end of data push cx ; - yes mov cx,12 ; checksum pseudo hdr mov si,[bx].dPtrIp add si,iIpTtl call ChkSum mov [di].uUdpXsum,cx ; move partial checksum ; into udp hdr pop cx ; checksum udp hdr+data mov si,di call ChkSum jnz UdpNotZero ; checksum is zero? not ax ; - yes, make it FFFFh UdpNotZero: mov [di].uUdpXsum,ax cmp ax,dx ; does checksums match? UdpNoSum: pop cx mov di,[bx].dPtrIp mov [di].iIpTtl,cl ; restore ttl ret UdpChkSum endp ;************************************************************************ ;* IpHdrLength ;* ;* Input: BX = IP description buffer ptr (saved) ;* Output: CX = IP header byte length ;* SI = pointer to IP header ;* Destroys: SI, flags ;************************************************************************ IpHdrLength proc near mov si,[bx].dPtrIp mov cx,[si] ; get version+length byte and cx,0fh ; length (32 bit words) shl cx,1 ; convert to shl cx,1 ; byte length ret IpHdrLength endp ;************************************************************************ ;* IpChkSum (both for generate and check!) ;* ;* Input: BX = IP description buffer ptr (saved) ;* Output: Zero if OK; checksum filled in ;* Destroys: AX, CX, DX, SI, DI, flags ;************************************************************************ IpChkSum proc near xor dx,dx mov di,[bx].dPtrIp xchg dx,[di].iIpXsum ; save and clear checksum call IpHdrLength call ChkSum ; calculate new checksum mov [di].iIpXsum,ax cmp ax,dx ; does checksums match? ret IpChkSum endp ;************************************************************************ ;* IcmpChkSum (both for generate and check!) ;* ;* Input: BX = IP description buffer ptr (saved) ;* CX = IP data length ;* Output: Zero if OK; checksum filled in ;* Destroys: AX, CX, DX, SI, DI, flags ;************************************************************************ IcmpChkSum proc near xor dx,dx mov di,[bx].dPtrUdp xchg dx,[di].uIcmpXsum ; save and clear checksum mov si,di call ChkSum ; calculate new checksum mov [di].uIcmpXsum,ax cmp ax,dx ; does checksums match? ret IcmpChkSum endp ;************************************************************************ ;* CurrentTicks ;* Output: CX = low word of ticks (1/18 second) counter ;* Destroys: CX, ES ;************************************************************************ CurrentTicks proc near mov cx,040h ; DOS data segment mov es,cx mov cx,es:6ch ; get low word of ticks cntr push cs pop es ret CurrentTicks endp if RFCC ;************************************************************************ ;* Ageing of ARP and Route tables ;* ;* Destroys: AX, CX, DX, SI, DI, ES, flags ;************************************************************************ AgeNext dw 0 ; time to check slots Ageing proc near PushfDI call CurrentTicks ; get current ticks value cmp cx,AgeNext jns AgeNow ; time to do ageing? PopfEI ret AgeNow: mov di,cx mov dx,cx add cx,2*18 ; chk next 2 seconds from now mov AgeNext,cx sub dx,65*18 ; clear what is older than 1 min mov cx,ARPSLOTS-3 mov si,offset ArpTabTr+6 AgeArpLoop: and word ptr [si+2*ARPSLOTS],not SQ_UPDATED ; clr every 2 s lodsw cmp ax,dx jns AgeArpYoung ; not touched in a minute? sub si,offset ArpTabTr+2 push cx push di push dx mov dx,ArpTabIp1[si] mov ax,ArpTabIp2[si] call switchGwy ; in case it's a gwy: switch pop dx pop di pop cx xor ax,ax mov ArpTabTr[si],di ; set current time mov ArpTabIp1[si],ax ; clear old entries mov ArpTabIp2[si],ax mov ArpTabHw1[si],ax mov ArpTabHw2[si],ax mov ArpTabHw3[si],ax add si,offset ArpTabTr+2 AgeArpYoung: loop AgeArpLoop PopfEI mov cx,ROUTESLOTS mov si,offset RouteTabTrRx PushfDI AgeRouteLoop: and word ptr [si+2*ROUTESLOTS],not SQ_UPDATED ; clr every 2 s lodsw cmp ax,dx ; old slot? jns AgeRouteYoung sub si,offset RouteTabTrRx+2 mov RouteTabTrRx[si],di xor ax,ax cmp RouteTabUnreach[si],ax ; any error code? jne AgeRouteUnr cmp dx,RouteTabTrTx[si] ; - no. Sent anything lately? jns AgeRouteEnd ; - no, that's why mov RouteTabUnreach[si],SERRNOTRAF ;- yes, somebody is dead jmp short AgeRouteEnd AgeRouteUnr: ; - yes, remove slot mov RouteTabIpD1[si],ax mov RouteTabIpD2[si],ax mov RouteTabIpG1[si],ax mov RouteTabIpG2[si],ax AgeRouteEnd: add si,offset RouteTabTrRx+2 AgeRouteYoung: loop AgeRouteLoop PopfEI call AgeFrags ; release old fragments ret Ageing endp ;************************************************************************ ;* VerifyIpHdr (RFC1122 requirements) ;* ;* verify IP dst = me (or bcast), process IP options, verify IPver=4, ;* verify IP src not bcast, set timer value in ArpTab and RouteTab. ;* Process IP fragments. ;************************************************************************ holeStruc struc holeNext dw 0 holeFirst dw 0 holeLast dw 0 HOLEDESCRLEN equ $-holeNext holeStruc ends k18 db 18 VerifyIpHdr proc near push si push di mov al,[di].iIpVerHlen and al,0f0h cmp al,040h ; IP version 4? jne VerifyErr1 mov di,[bx].dPtrPhys mov si,[di] mov dx,[di+2] mov ax,[di+4] call ArpFindHw ; find Hw Dst arp index mov [bx].dIdxHwDst,di ; 0 = bcast, 4 = me cmp MyIpNr,0 je VerifyMeNotInArp cmp di,ARPMYIDX ; is Hw addr to me or bcats? ja VerifyErr1 VerifyMeNotInArp: mov di,[bx].dPtrPhys add di,Hlen ; get physical src addr mov si,[di] mov dx,[di+2] mov ax,[di+4] call ArpFindHw ; is Hw Src in arp table? jz VerifyChkBcast ; - yes cmp [bx].dIdxHwDst,ARPMYIDX ; - no. Addressed to me? jne VerifyIpDst ; pop di ; - yes push di mov dx,[di].iIpSrc mov ax,[di].iIpSrc+2 call MyNetChk ; if he is on my net jnz VerifyIpDst mov si,[bx].dPtrPhys add si,Hlen call ArpPutNew ; add him to arp table jmp short VerifyIpDst VerifyErr1: jmp short VerifyErr VerifyChkBcast: cmp di,ARPMYIDX ; from me or broadcast? jbe VerifyErr ; - yes, ignore packet call CurrentTicks ; get current ticks value mov ArpTabTr[di],cx VerifyIpDst: cmp MyIpNr,0 je VerifyIpUnknown pop di push di mov dx,[di].iIpDst ; check IP dst mov ax,[di].iIpDst+2 call ArpFindIp mov [bx].dIdxIpDst,di cmp di,ARPMYIDX ; is it to me or broadcast? ja VerifyErr ; - no, ignore packet VerifyIpUnknown: pop di push di mov dx,[di].iIpSrc mov ax,[di].iIpSrc+2 call ArpFindIp jnz VerifyNoArp cmp di,ARPMYIDX ; from IP broadcast? jb VerifyErr ; -yes, ignore packet VerifyOK: call AgeFrags ; release old reassembly bufs pop di push di test [di].iIpFlFrag,0ff3fh ; is this a fragment? jnz VerifyFrag clc ; - no, use as is VerifyRet: pop di pop si ret VerifyNoArp: pop di push di mov cl,[di].iIpTos xor ch,ch mov si,cx call RouteFind ; is he in route table? jnz VerifyNoRoute call CurrentTicks mov RouteTabTrRx[di],cx ; note we've got pkts from him VerifyNoRoute: jmp short VerifyOK FragAddAndErr: mov si,offset FragList call AddToList VerifyFragErr: mov bx,bp VerifyErr: call BufRelease VerifyKeep: stc jmp short VerifyRet VerifyFrag: ; RFC 815 fragment reassembly: mov bp,bx ; addr of fragment buffer mov dx,[di].iIpSrc ; get IP # / IP id / IP prot mov ax,[di].iIpSrc+2 mov si,[di].iIpId mov cx,Fraglist.lBufsAvail mov ch,[di].iIpProt FragLook4Buf: mov di,offset FragList call GetFromList jz FragEarliest ; any reassembly buffers? mov di,[bx].dPtrIp ; match IP#/Id/Prot cmp dx,[di].iIpSrc jne FragNextBuf cmp ax,[di].iIpSrc+2 jne FragNextBuf cmp si,[di].iIpId jne FragNextBuf cmp ch,[di].iIpProt je FragBufFound FragNextBuf: push si ; irrelevant buf, put it back mov si,offset FragList call AddToList pop si dec cl jnz FragLook4Buf FragEarliest: call FragFirstLast ; compute addr of fragment or ax,ax ; first part earliest? jnz FragOffset mov bx,bp mov di,[bx].dPtrUdp add di,dx cmp [bp].dHomeList,offset FreeBufs ; and a big buffer? je FragFirstHole ; - yes, no extra buffer needed FragOffset: call BufAlloc ; - no, create empty buffer jz VerifyFragErr add di,2+2*EADDR_LEN mov [bx].dPtrIp,di mov si,[bp].dPtrIP mov cx,[bp].dPtrUdp ; copy IP header sub cx,si call movemem mov [bx].dPtrUdp,di FragFirstHole: mov [di].holeNext,0 ; create first hole descriptor mov [di].holeFirst,0 mov [di].holeLast,GIANT mov [bx].dPtrFrag,di add di,HOLEDESCRLEN ; mark end of info mov [bx].dPktEnd,di FragBufFound: call FragFirstLast ; compute addr of fragment lea di,[bx].dPtrFrag FragNextHole: ; 1. select next hole descr mov si,di mov di,[si].holeNext or di,di ; any more descriptors? jz FragEndHoles cmp ax,[di].holeLast ; 2. frag.first > hole.last? jae FragNextHole cmp dx,[di].holeFirst ; 3. frag.last < hole.first? jbe FragNextHole mov cx,[di].holeNext ; 4. delete current hole descr mov [si].holeNext,cx mov cx,[di].holeLast cmp ax,[di].holeFirst ; 5. frag.first > hole.first? jbe FragNoNew1 mov [si].holeNext,di ; create new hole descr mov [di].holeLast,ax FragNoNew1: mov si,[bp].dPtrIp ; 6. if frag.more test [si].iIpFlFrag,0020h jz FragLastFrag cmp dx,cx ; and frag.last < hole.last? jae FragNextHole mov si,[bx].dPtrUdp add si,dx mov [si].holeFirst,dx ; create new hole descr mov [si].holeLast,cx mov cx,[bx].dPtrFrag mov [si].holeNext,cx mov [bx].dPtrFrag,si add si,HOLEDESCRLEN cmp si,[bx].dPktEnd jbe FragNextHole FragPktEnd: mov [bx].dPktEnd,si jmp short FragNextHole FragLastFrag: ; when last frag mov si,[bx].dPtrUdp ; prepare IP length add si,dx jmp short FragPktEnd FragEndHoles: ; 8. copy data to assembly buf cmp bx,bp ; do we need to copy? je FragTimeUpd or ax,ax ; if first frag jnz FragNotFirst mov si,[bx].dPtrUdp ; retain this IP header mov di,[bp].dPtrUdp ; and copy assembled data mov cx,[bx].dPktEnd ; to frag buffer sub cx,si add si,dx ; skip over first fragment add di,dx sub cx,dx call movemem mov [bp].dPktEnd,di mov cx,[bx].dPtrFrag mov [bp].dPtrFrag,cx xchg bx,bp ; and switch buffers mov cx,di sub cx,si ; hole ptr adjustment lea di,[bx].dPtrFrag FragUpdLoop: mov si,di mov di,[si].holeNext or di,di jz FragRelBuf ; end of hole list add di,cx mov [si].holeNext,di ; new pointer address jmp short FragUpdLoop FragNotFirst: mov si,[bp].dPtrUdp ; copy this frag to asm buf mov cx,dx sub cx,ax mov di,[bx].dPtrUdp add di,ax call movemem FragRelBuf: push bx ; release frag buf mov bx,bp call BufRelease pop bx FragTimeUpd: call CurrentTicks ; update timer entry mov di,[bx].dPtrIp mov al,[di].iIpTtl mul k18 add cx,ax mov [bx].dTickTimeout,cx mov di,[bx].dPtrIp mov si,[bx].dPtrUdp cmp [bx].dPtrFrag,0 ; any holes? jne FragKeep ; - yes, wait for more pkts mov cx,[bx].dPktEnd ; - no mov ax,cx ; compute IP length sub cx,[bx].dPtrIp xchg ch,cl mov [di].iIpLen,cx sub ax,[bx].dPtrPhys mov [bx].dPktLen,ax ; and packet length add sp,4 ; pop si and pop di ret FragKeep: mov si,offset FragList ; keep buf a while call AddToList jmp VerifyKeep VerifyIpHdr endp ;************************************************************************ ;* FragFirstLast ;************************************************************************ FragFirstLast proc near mov di,[bp].dPtrIp ; compute frag.first mov ax,[di].iIpFlFrag xchg ah,al and ax,1fffh shl ax,1 shl ax,1 shl ax,1 mov dx,[di].iIpLen ; compute frag.last (+1) xchg dh,dl add dx,[bp].dPtrIp sub dx,[bp].dPtrUdp add dx,ax cmp dx,GIANT-IPHDRLEN-HWHDRLEN ; fits in buffer? ja FragTooBig ret FragTooBig: add sp,2 ; remove return addr from stack jmp FragAddAndErr FragFirstLast endp ;************************************************************************ ;* AgeFrags ;************************************************************************ AgeFragsNext dw 0 AgeFrags proc near call CurrentTicks cmp cx,AgeFragsNext jns AgeFragsNow ; time to age yet? ret AgeFragsNow: mov dx,cx add cx,2*18 ; check next in 2 seconds mov AgeFragsNext,cx push bx PushfDI mov cx,Fraglist.lBufsAvail AgeLook4Buf: mov di,offset FragList call GetFromList jz AgeNoMoreFrags ; any reassembly buffers? mov si,offset FragList cmp dx,[bx].dTickTimeout js AgenextBuf ; too old? ; - no, put it back mov si,[bx].dHomeList ; - yes, release it AgeNextBuf: call AddToList dec cl jnz AgeLook4Buf ; any more reassembly bufs? AgeNoMoreFrags: PopfEI pop bx ret AgeFrags endp endif ; RFCC ;************************************************************************ ;* SwitchIpDst ;************************************************************************ SwitchIpDst proc near mov si,[bx].dPtrIp SwitchIpDstB: mov dx,[si].iIpSrc ; mov his IP # to IP dst mov di,[bx].dPtrIp mov [di].iIpDst,dx mov dx,[si].iIpSrc+2 mov [di].iIpDst+2,dx ret SwitchIpDst endp ;************************************************************************ ;* InitIp ;************************************************************************ InitIp proc near pushf pop ax or ax,7000h ;the 386 lets us set these bits push ax popf pushf pop ax test ax,7000h ;did the bits get set? jz IsNot386 ;no. or GenFlags,IS_386 ;yes, use a 386-optimized code IsNot386: push ds mov IpDesBuf.dPtrPhys,offset IpDesBuf.fHwStruc ; *test* mov IpDesBuf.dPtrIp,offset IpDesBuf.fIpStruc mov IpDesBuf.dPtrUdp,offset IpDesBuf.fBotStruc mov ax,1ffh ;driver_info int_pkt pop ds call fatal_error mov ah,2 ;access all packets. mov al,ch ;their class from driver_info(). mov bx,dx ;their type from driver_info(). mov dl,cl ;their number from driver_info(). mov cx,2 ;type length of two. mov si,offset IpDesBuf.fHwStruc.hProtType push cs ;es:di -> our receiver. pop es mov di,offset IpRecv push ds int_pkt pop ds call fatal_error mov IpHandle,ax ret InitIp endp ;************************************************************************ ;* EndProtocol ;************************************************************************ EndProtocol proc near mov ah,3 ; release handle in bx push ds int_pkt pop ds call print_error ret EndProtocol endp ;************************************************************************ ;* Terminate ;************************************************************************ Terminate proc near pop bx ; remove return addr fr stack push ax cld push cs push cs pop ds pop es sti mov bx,IpHandle ; release ARP and IP handles call EndProtocol mov bx,ArpHandle call EndProtocol if PINGCLIENT cmp EchoTarget,0 jz TermNoPing call RestoreTimer TermNoPing: endif ; PINGCLIENT pop ax push ax or al,al ; any errors? jz termnorm cmp EnoughWord,HAVE_MYIPNR ; clock errors? je termnorm mov dx,offset MsgNotSet ; display "clock not set" mov ah,9 int 21h termnorm: pop ax push ax add al,'0' mov MsgTermNr,al ; show error # in end line mov si,offset MyHwAd mov di,offset MsgTermHw call PutHwNum ; put my HW addr mov si,offset MyIpNr mov di,offset MsgMyIp call PutIpNum ; put my IP # mov dx,offset MsgTerm ; End of PDCLKSET msg mov ah,9 int 21h pop ax ; error code mov ah,4ch int 21h ; terminate program Terminate endp ;************************************************************************ ;* IP receiver * ;************************************************************************ IpRecv: pushf push ds ; set segment registers mov dx,cs mov ds,dx mov es,dx cld or ax,ax ; first or second call? jne IpRecv_1 ; - second, we've got data ; - first, they want a buf cmp cx,GIANT ; packet too long? ja IpRecTooBig if PINGCLIENT cmp cx,BUFBODYSML ja IpRecBig call BufAlSml jz IpRecBig pop ds popf retf IpRecBig: endif ; PINGCLIENT call BufAlloc ; get a receive buffer jz IpRecNoBuf IpRecRet0: pop ds popf retf if DEBUG DbgIpRecv: or GenFlags,DBGINTERR endif ; DEBUG IpRecNoBuf: if PINGCLIENT inc EchoDrop endif ; PINGCLIENT IpRecTooBig: xor di,di ; no buffer available mov es,di jmp short IpRecRet0 IpRecv_1: ; If I understand PC interrupt handling correctly, the following stackswitch ; and interrupt enabling should not kill multiprocess reentrancy. cli ; switch to our mov word ptr SaveSP,sp ; interrupt stack mov word ptr SaveSS,ss mov sp,offset StackEnd mov ss,MySegm sti ; allow interrupts if DEBUG dec DbgIntCnt ; double interrupt? jnz DbgIpRecv endif ; DEBUG call BuildRecDescr ; calculate pointers etc call IpChkSum ; only accept a correct jne IpRecRet ; IP checksum mov [bx].dPtrUdp,si if RFCC call VerifyIpHdr ; verify and process IP hdr jc IpRecKeepBuf endif ; RFCC cmp [di].iIpProt,ICMP_PROT ; ICMP protocol? jne IpNotIcmp jmp IpRecIcmp IpNotIcmp: cmp [di].iIpProt,UDP_PROT ; UDP protocol? jne IpProtUnr call UdpChkSum ; if available, test jne IpRecRet ; UDP checksum cmp si,[bx].dPktEnd ; still within packet limit? jbe IpRecUdp IpRecRet: call BufRelease ; release receive buffer IPRecKeepBuf: if DEBUG inc DbgIntCnt endif ; DEBUG cli ; restore previous stack mov sp, word ptr SaveSP mov ss, word ptr SaveSS pop ds popf retf IpPortUnr: mov ah,3 ; port unreachable jmp short IpUnr IpProtUnr: mov ah,2 ; protocol unreachable IpUnr: if RFCC mov al,3 ; destination unreachable cmp [bx].dIdxHwDst,ARPMYIDX ; was it specifically to me? jne IpRecRet mov bp,bx call BufAlloc jz UnrEnd call MakeSendDescr mov si,[bp].dPtrIp ; copy IP header mov cx,[bp].dPtrUdp add cx,8 ; + 8 bytes sub cx,si call SwitchIpDstB ; return to sender mov di,[bx].dPtrUdp mov [di].uIcmpTypecode,ax ; set type and code add di,8 call movemem sub di,[bx].dPtrUdp mov [bx].dPktLen,di ; set IP data length mov si,offset IcmpToDo ; put buf on the ICMP send list call AddToList UnrEnd: mov bx,bp endif ; RFCC jmp IpRecRet IpRecUdp: mov [bx].dPktEnd,si ; end of logical pkt mov di,[bx].dPtrUdp cmp word ptr [di].uUdpSrc,2500h ; Src port 0025 = 37 ? je IpRecvTime ; - must be time reply if TBLBUILD or PINGCLIENT cmp word ptr [di].uUdpSrc,3500h ; Name server (53)? jne $+5 jmp IpRecvName endif ; TBLBUILD or PINGCLIENT cmp word ptr [di].uUdpSrc,4300h ; Src port 0043 = 67 jne IpPortUnr cmp word ptr [di].uUdpDst,4400h ; Dst port 0044 = 68 jne IpPortUnr cmp byte ptr [di].uBotOp,2 ; bootp reply? jne IpRecRet IpRecBootp: push di ; - must be bootp reply lea si,[di].uBotCliHwAd mov di,offset MyHwAd mov cx,Hlen repe cmpsb ; our Ethernet addr? pop di jne IpRecRet2 mov ax,word ptr IpDesBuf.fBotStruc.uBotXid cmp ax,word ptr [di].uBotXid ; our random id? jne IpRecRet2 mov ax,word ptr IpDesBuf.fBotStruc.uBotXid+2 cmp ax,word ptr [di].uBotXid+2 jne IpRecRet2 ; yes, it's about me! mov dx,[di].uBotGwyIp ; saves an ARP request mov ax,[di].uBotGwyIp+2 ; in many cases mov si,[bx].dPtrPhys add si,Hlen call ArpPutNew test Events,GOT_BOOTP ; if first answer jnz IpRecRet2 ; save bootp answer mov AdrBootpReply,bx ; for further study or Events,GOT_BOOTP jmp IpRecKeepBuf IpRecvTime: test Events,GOT_TIMEREPLY ; already got reply? jnz IpRecRet2 mov ax,[di].uUdpData ; save seconds mov cTime,ax ; since year 1900 mov ax,[di].uUdpData+2 mov cTime+2,ax mov di,[bx].dPtrIp ; save who was answering mov dx,[di].iIpSrc mov ax,[di].iIpSrc+2 mov RespondingIpNr,dx mov RespondingIpNr+2,ax or Events,GOT_TIMEREPLY IpRecRet2: jmp IpRecRet if TBLBUILD or PINGCLIENT IpRecvName: mov si,offset NameToDo ; process nameserver reply call AddToList jmp IpRecKeepBuf endif ; TBLBUILD or PINGCLIENT IpRecIcmp: mov cx,[di].iIpLen ; calculate IP data length xchg ch,cl add cx,di sub cx,si mov [bx].dPktLen,cx ; save IP data length call SwitchIpDst ; in case we want to return it call IcmpChkSum ; valid ICMP checksum? jne IpRecRet2 mov si,[bx].dPtrUdp ; point to ICMP header mov cx,[si].uIcmpTypecode ; get type and code mov dx,[si].uIcmpIpHdr.iIpDst ; get original IP hdr mov ax,[si].uIcmpIpHdr.iIpDst+2 ; dst IP # if PINGCLIENT cmp cl,0 ; echo reply? jne IpNotEchoReply call EchoCalc jmp IpRecRet endif ; PINGCLIENT if RFCC IpNotEchoReply: cmp cl,8 ; echo request? jne IpNotEchoReq cmp [bx].dIdxHwDst,ARPMYIDX ; broadcast? jb IpRecRet2 ; - yes, don't echo mov byte ptr [si].uIcmpTypecode,0 ; put echo reply value mov si,offset IcmpToDo ; put buf on the ICMP send list call AddToList jmp IpRecKeepBuf IpNotEchoReq: endif ; RFCC cmp cx,11 ; TTL exceeded? je IpIcmpUnreach cmp cl,3 ; unreachable jne IpNotUnreach cmp ch,12 ; net or host unreachable? ja IpIcmpRet2 cmp ch,6 ja IpIcmpUnreach cmp ch,1 ja IpIcmpRet2 IpIcmpUnreach: ; codes 0 - 1, 6 - 12 go here PushfDI push si mov cl,[si].uIcmpIpHdr.iIpTos xor ch,ch mov si,cx call RouteFind ; this host in route table? pop si jnz IpIcmpUnfound mov ah,byte ptr [si].uIcmpTypeCode+1 ; icmp code xor al,al ;*test inc ah ; ensure non zero error code mov RouteTabUnreach[di],ax ; mark it unreachable call CurrentTicks ; get current ticks value mov RouteTabTrRx[di],cx ; set timer IpIcmpUnfound: PopfEI IpIcmpRet2: jmp IpIcmpRet IpNotUnreach: if RFCC cmp cl,4 ; source quench jne IpIcmpNotQuench PushfDI push si mov cl,[si].uIcmpIpHdr.iIpTos xor ch,ch mov si,cx call RouteFind ; this host in route table? pop si jnz IpIcmpNotRoute mov dx,RouteTabFlags[di] or RouteTabFlags[di],SQ_UPDATED lea si,RouteTabTrSq[di] lea di,RouteTabSqDelay[di] jmp short IpIcmpSq IpIcmpNotRoute: call ArpFindIp jnz IpIcmpSqEnd mov dx,ArpTabFlags[di] or ArpTabFlags[di],SQ_UPDATED lea si,ArpTabTrSq[di] lea di,ArpTabSqDelay[di] IpIcmpSq: mov ax,[di] ; get current sq delay or ax,ax jnz IpIcmpAddDelay call CurrentTicks mov [si],cx ; initialize sq timer mov ax,150*64/55 ; initial sq delay 178 ms IpIcmpAddDelay: add ax,28*64/55 ; increase delay by 28 ms test dx,SQ_UPDATED ; unless already done in jnz IpIcmpSqEnd ; the last two seconds mov [di],ax IpIcmpSqEnd: PopfEI jmp short IpIcmpRet IpIcmpNotQuench: endif ; RFCC cmp cl,5 ; redirect jne IpNotRedirect PushfDI push si mov cl,[si].uIcmpIpHdr.iIpTos xor ch,ch mov si,cx call RouteFind ; this host in route table? pop si jnz IpIcmpDisfound mov dx,RouteTabIpG1[di] ; icmp from the gwy used? mov ax,RouteTabIpG2[di] mov cx,di mov di,[bx].dPtrIp cmp dx,[di].iIpSrc jne IpIcmpDisfound cmp ax,[di].iIpSrc+2 jne IpIcmpDisfound mov di,cx mov dx,[si].uIcmpData ; new gateway IP # mov ax,[si].uIcmpData+2 call MyNetChk ; is he on my net? jnz IpIcmpDisfound mov RouteTabIpG1[di],dx ; put it into route table mov RouteTabIpG2[di],ax IpIcmpDisfound: PopfEI jmp short IpIcmpRet IpNotRedirect: IpIcmpRet: jmp IpRecRet ;************************************************************************ ;* MakeMynet ;************************************************************************ MakeMynet proc near mov dx,MyIpNr mov ax,MyIpNr+2 mov ArpTabIp1+4,dx ; third arp slot = me mov ArpTabIp2+4,ax mov si,offset MyHwAd call ArpPutNew mov si,MyMask mov di,MyMask+2 and dx,si ; calculate network # and ax,di mov MyNet,dx mov MyNet+2,ax not si ; second arp slot = not di ; subnet broadcast or dx,si or ax,di mov ArpTabIp1+2,dx mov ArpTabIp2+2,ax ret MakeMynet endp ;************************************************************************ ;* ValidateIpNr ;************************************************************************ ValidateIpNr proc near call BufAlloc mov [bx].dTimOutMsg,0 ; we SHOULD get no answer mov [bx].dTickTimeout,10 ; give them half a second mov dx,MyIpNr mov ax,MyIpNr+2 call SendArpReq ; send arp to our Ip # call BufRelease jz ValConflict ; someone else has our IP # ? ret ; - no, return ValConflict: ; - yes, error termination call ArpFindIp mov cl,3 shl di,cl lea si,ArpTabHwAdr[di] ; get HW addr of arp reply mov di,offset OccupiedHw call PutHwNum ; put offending HW addr mov dx,offset OccupiedMsg ; display IP occupied msg mov ah,9 int 21h mov al,09 ; error code 9 call terminate ValidateIpNr endp ;************************************************************************ ;* DoBootpPkt ;************************************************************************ DoBootpPkt proc near call CurrentTicks ; get current ticks value mov IpDesBuf.fBotStruc.uBotXid,cx ; as transaction id if RFCC add cx,2*18 ; initialize ageing mov AgeNext,cx mov AgeFragsNext,cx endif ; RFCC mov al,byte ptr ArpBuf.iArpHtype+1 mov IpDesBuf.fBotStruc.uBotHtype,al ; put my HW type mov si,offset MyHwAd mov di,offset IpDesBuf.fBotStruc.uBotCliHwAd push cs pop es mov cx,Hlen mov IpDesBuf.fBotStruc.uBotHlen,cl rep movsb ; copy my HW addr mov bx,offset IpDesBuf ; frame to send call MakeSendDescr mov [bx].dWaitEvent,GOT_BOOTP ; event to wait for mov [bx].dTimOutMsg,offset NoBotReplyMsg ; error msg mov ax,BpDataLen+UDPHDRLEN ; bootp pkt length call SendUdpPkt ; send bootp request ret DoBootpPkt endp ;************************************************************************ ;* InterpBootp according to RFC 1084 and RFC1048 ;************************************************************************ InterpBootp proc near mov bx,AdrBootpReply mov di,[bx].dPtrUdp mov dx,[di].uBotYourIp ; mov my IP # mov MyIpNr,dx ; to IP buf mov ax,[di].uBotYourIp+2 mov MyIpNr+2,ax or Flagword,HAVE_MYIPNR ; note what we've got cmp word ptr [di].uBotMagNum,8263h ; RFC 1084 type of jne VendEnd ; vendor area? cmp word ptr [di].uBotMagNum+2,6353h jne VendEnd lea si,[di].uBotVend ; start of "vendor area" lea bp,[si]+64-4 ; end of "vendor area" push cs pop es VendLoop: cmp si,bp ; beyond vendor area? jb VendNext VendEnd: call BufRelease ; release bootp reply buf ret VendNext: lodsb ; get field type: cmp al,0 ; filler je VendLoop cmp al,1 ; netmask jne NotMask mov di,offset MyMask call Xtract4Bytes jmp short VendLoop NotMask: cmp al,2 ; zone/time (?) offset jne NotTimeOffs test Flagword,HAVE_TIMEOFFSET jnz VendDefault mov di,offset tzoffset call Xtract4Bytes or Flagword,HAVE_TIMEOFFSET jmp short VendLoop NotTimeOffs: cmp al,3 ; default gateways jne NotDefGwys mov di,offset DefGwys mov cx,MAXDEFGWYS mov ax,DefGwyNum call XtractIpNums add DefGwyNum,cx jmp short VendLoop NotDefGwys: cmp al,4 ; time servers jne NotTimeserv or Flagword,HAVE_TIMESERVER mov di,offset TimeServIpNr mov cx,MAXTSERVS mov ax,TservNum call XtractIpNums add TservNum,cx jmp short VendLoop NotTimeserv: if TBLBUILD or PINGCLIENT cmp al,6 ; default nameservers jne NotDefNS mov di,offset DefNS mov cx,MAXDEFNS mov ax,DefNSnum call XtractIpNums add DefNSnum,cx jmp short VendLoop NotDefNS: endif ; TBLBUILD or PINGCLIENT cmp al,0ffh ; end je VendEnd VendDefault: ; everything else lodsb xor ah,ah add si,ax ; skip field jmp Vendloop InterpBootp endp ;************************************************************************ ;* XtractIpNums ;************************************************************************ XtractIpNums proc near sub cx,ax ; wanted - already got shl ax,1 shl ax,1 add di,ax ; append to what we got shl cx,1 shl cx,1 jmp short XtractNBytes Xtract4Bytes: mov cl,4 XtractNBytes: lodsb cmp cl,al ; as many as we want? jbe XtractOkLen mov cl,al ; - no, take what there is XtractOkLen: xor ch,ch xor ah,ah push cx push ax push si rep movsb ; copy field pop si pop ax add si,ax ; advance field ptr pop cx shr cx,1 shr cx,1 ; cx = IP #'s read ret XtractIpNums endp ;======================================================================== ; endinclude