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Assembly Source File | 1993-10-09 | 51.9 KB | 2,298 lines

; ip.asm ;======================================================================== ; Copyright (C) 1991 by Jan.Engvald@ldc.lu.se, see file COPYING. ; 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 SERRNOIP equ 10 ; no IP # to send to ICMP_PROT equ 1 ; Internet Control Msg Prot UDP_PROT equ 17 ; IP protocol type UDP 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 IpStruc ends IPHDRLEN equ SIZE IpStruc 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 UdpStruc ends UDPHDRLEN equ SIZE UdpStruc 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 BootpStruc ends BPDATALEN equ SIZE BootpStruc IcmpStruc struc uIcmpTypecode dw 0 uIcmpXsum dw 0 uIcmpData dw 0, 0 uIcmpIpHdr equ $-uIcmpTypecode IcmpStruc ends ICMPHDRLEN equ SIZE IcmpStruc even IpHandle dw 0 MyMask dw 2 dup (0h) MyNet dw 2 dup (0h) MyIpNr dw 0, 0 IpIdCounter dw 0 BootpXid dw 0 AdrBootpReply dd 0 ; save address of bootp reply if RFCC AgeNext dw 0 ; time to check slots AgeFragsNext dw 0 endif ; RFCC 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 assume ds:nothing ;************************************************************************ ;* SendUdpFind ;* ;* Input: DS:BX = IP description buffer ptr (saved) ;* DS:[BX].dPktLen = IP data byte length ;* CS:DX = addr of length prepended IP list to send to ;* until reply received ;* 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 lods byte ptr cs:[TservNum] ; # of IP numbers to al mov cx,SERRNOIP or al,al jz SendUdpFindRet inc si SendNextIP: push ds pop es mov di,[bx].dPtrIp lea di,[di].iIpDst ; put next IP number movs es:[iIpDst],word ptr cs:[TimeServIpNr] movs es:[iIpDst+2],word ptr cs:[TimeServIpNr] 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? SendUdpFindRet: or cx,cx ret SendUdpFind endp ;************************************************************************ ;* SendUdpPkt ;* ;* Input: DS:BX = IP description buffer ptr (saved) ;* DS:[BX].dPktLen = IP data byte length ;* 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 mov dx,cs:MyIpNr ; fill in my IP # (used mov di,[bx].dPtrIp ; in udp chksum!) mov [di].iIpSrc,dx mov dx,cs:MyIpNr+2 mov [di].iIpSrc+2,dx mov ax,[bx].dPktLen xchg ah,al mov si,[bx].dPtrUdp mov [si].uUdpLen,ax ; fill in UDP total length mov [si].uUdpXsum,ax ; ensure chksum is calculated mov [di].iIpProt,UDP_PROT ; set UDP protocol call UdpChkSum ; calculate UDP checksum jmp short SendIpPkt ; send UDP packet SendUdpPkt endp ;************************************************************************ ;* SendIcmpPkt ;* ;* Input: DS:BX = IP description buffer ptr (saved) ;* DS:[BX].dPktLen = IP data byte 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 call IcmpChkSum ; calculate icmp checksum mov di,[bx].dPtrIp mov [di].iIpProt,ICMP_PROT SendIcmpReply: mov [bx].dWaitEvent,0 ; don't wait for answer ; call SendIpPkt ; ret SendIcmpPkt endp ;************************************************************************ ;* SendIpPkt ;* ;* Input: DS:BX = IP description buffer ptr (saved) ;* DS:[BX].dPktLen = IP data byte length ;* 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 mov di,[bx].dPtrIp ; calculate IP hdr length mov cx,[bx].dPtrUdp sub cx,di mov dx,cs:MyIpNr ; my IP # to IP src mov [di].iIpSrc,dx mov dx,cs:MyIpNr+2 mov [di].iIpSrc+2,dx mov ax,[bx].dPktLen add ax,cx ; add hdr length to data length mov [bx].dPktLen,ax ; and save it xchg ah,al mov [di].iIpLen,ax ; fill in IP length mov dx,cs:IpIdCounter mov [di].iIpId,dx ; unique id for frag reassembly inc dx mov cs:IpIdCounter,dx call IpChkSum ; calculate checksum cmp byte ptr cs:ArpBuf.iArpHtype+1,0 ; slip? je SendIpAndWait 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) SendIpAndWait: jmp SendAndWait ; -yes, send packet SendIpRet: ret SendIpPkt endp ;************************************************************************ ;* PutPhysDst ;* ;* Input: DS:BX = IP description buffer ptr (saved) ;* Output: Zero and CX = 0 if OK ;* non-zero and CX = errorcode if error ;* ES = DS ;* Destroys: AX, CX, DX, SI, DI, ES, flags ;************************************************************************ PutPhysDst proc near mov ax,cs:DefGwyNum ; # of default gwys we have mov [bx].dGwys2Chk,al ; gwys still left to check PutPhysAgain: mov ax,ds mov es,ax 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 ;* A PushfDI must be done before calling ;* 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 ;************************************************************************ RouteFindUtos proc near assume ds:nothing mov cl,[si].uIcmpIpHdr.iIpTos RouteFindCl: xor ch,ch mov si,cx RouteFind: mov es,cs:MySegm mov di,offset RouteTabIpD2 mov cx,ROUTESLOTS RouteFindNext: ; look for matching slot repne scasw jnz RouteFindRet cmp dx,cs:2*RouteSLOTS-2[di] ; does dst IP first part match? jne RouteFindNext ; - no, look further cmp si,cs:4*RouteSLOTS-2[di] ; does dst tos match? jne RouteFindNext ; - no, look further sub di,offset RouteTabIpD2+2 ;- yes, compute slot index mov dx,cs:RouteTabIpG1[di] ; get gwy IP # mov ax,cs:RouteTabIpG2[di] ; mov cx,cs:RouteTabUnreach[di] ; get unreachable code cmp di,di ; set zero flag RouteFindRet: ret RouteFindUtos endp ;************************************************************************ ;* MyNetChk ;* ;* Input: DX = first word of IP # (saved) ;* AX = second word of IP # (saved) ;* Output: zero if same net else non-zero ;* Destroys: CX, flags ;************************************************************************ MyNetChk proc near mov cx,dx and cx,cs:MyMask ; check if my net cmp cx,cs:MyNet jne MyNetRet mov cx,ax and cx,cs:MyMask+2 cmp cx,cs:MyNet+2 MyNetRet: ret MyNetChk endp ;************************************************************************ ;* UseGwy ;* ;* Input: DX = first word of destination IP # ;* AX = second word of destination IP # ;* SI = IP type of service ;* ES:BX = IP descriptor buffer ptr (saved) ;* Output: DX = first word of gateway IP # ;* AX = second part of gateway IP # ;* CX = net/host unreachable code ;* Destroys: CX, SI, DI, flags ;************************************************************************ UseGwy proc near assume ds:nothing push ds mov ds,cs:MySegm assume ds:code_s cli call RouteFind ; is dst in route tbl? jz 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 mov cx,SavedTicks 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 mov cx,SavedTicks mov RouteTabTrTx[di],cx ; transmit time mov ax,RouteTabSqDelay[di] ; move sq delay to descriptor mov es:[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: pop ds assume ds:nothing sti ret UseGwyNone: assume ds:code_s mov dx,offset NoGwyMsg ; - no, print error msg in dx mov al,08 ; error code 8 call PrTerminate assume ds:nothing 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 push ds mov ds,cs:MySegm assume ds:code_s mov es,MySegm 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 pop ds assume ds:nothing ret SwitchGwy endp ;************************************************************************ ;* ChkSum ;* Input: DS:SI = start addr ;* CX = # of bytes (at least 6) ;* Output: AX = 1-complement checksum ;* DS:SI = addr of next byte ;* Destroys: SI, Flags ;************************************************************************ ChkSum proc near if PINGCLIENT test cs:GenFlags,IS_A_386 jz ChkSum8086 .386 push edx ; save 386 registers push eax xor edx,edx ; clear edx .8086 shr cx,1 ; divide by two, round down pushf ; keep odd bit in carry test si,2 ; double-word aligned? jz ChkAligned lodsw mov dx,ax dec cx ChkAligned: shr cx,1 ; divide by two, round down pushf ; keep odd bit in carry shr cx,1 ; divide by two, round down jnc ChkLoop386 .386 lodsd ; process 4 bytes add edx,eax jcxz ChkLoopEnd ChkLoop386: lodsd ; process n*8 bytes adc edx,eax lodsd adc edx,eax loopw ChkLoop386 ChkLoopEnd: adc edx,0 ; add the last carry in again mov eax,edx ; add double word parts shr eax,16 .8086 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: .386 pop eax ; restore saved regs mov ax,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 shr cx,1 ; divide by two, round down jnc ChkLoop lodsw ; process odd word add dx,ax ChkLoop: lodsw ; process even # of words adc dx,ax lodsw adc dx,ax 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 ; restore saved regs pop dx not ax ; take one more 1-complement ret ChkSum endp ;************************************************************************ ;* UdpChkSum (both for generate and check!) ;* ;* Input: DS:BX = IP description buffer ptr (saved) ;* DS:DI = IP ptr ;* DS:SI = UDP ptr ;* Output: Zero if OK; checksum filled in ;* DS:SI = addr of next byte ;* DS:DI = IP Ptr ;* Destroys: AX, CX, DX, SI, flags ;************************************************************************ UdpChkSum proc near xchg di,si xor dx,dx push word ptr [si].iIpTtl ; save ttl for pseudo hdr mov [si].iIpTtl,dl ; usage xchg dx,[di].uUdpXsum ; save and clear checksum push [si].iIpXsum ; save IP chksum for ps-hdr use mov cx,[di].uUdpLen ; put UDP length into ps-hdr 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 not ax ; move partial checksum mov [di].uUdpXsum,ax ; 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: mov di,[bx].dPtrIp pop [di].iIpXsum ; restore IP chksum pop word ptr [di].iIpTtl ; restore ttl ret UdpChkSum endp ;************************************************************************ ;* IpChkSum (both for generate and check!) ;* ;* Input: DS:BX = IP description buffer ptr (saved) ;* DS:DI = IpPtr ;* CX = IP hdr length ;* Output: Zero if OK; checksum filled in ;* Destroys: AX, CX, DX, SI, flags ;************************************************************************ IpChkSum proc near mov si,di xor dx,dx xchg dx,[di].iIpXsum ; save and clear checksum 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: DS:BX = IP description buffer ptr (saved) ;* Output: Zero if OK; checksum filled in ;* DI = dPtrUdp ;* Destroys: AX, CX, DX, SI, DI, flags ;************************************************************************ IcmpChkSum proc near mov cx,[bx].dPktlen mov si,[bx].dPtrUdp IcmpChkSum2: mov di,si xor dx,dx xchg dx,[di].uIcmpXsum ; save and clear checksum call ChkSum ; calculate new checksum mov [di].uIcmpXsum,ax cmp ax,dx ; does checksums match? ret IcmpChkSum endp ;************************************************************************ ;* Ageing of ARP and Route tables ;* ;* Destroys: AX, BX, CX, DX, SI, DI, ES, flags ;************************************************************************ Ageing proc near assume ds:code_s call CurrentTicks ; get current ticks value if RFCC cmp cx,AgeNext ; time to do route/arp ageing? jns AgeNow cmp cx,AgeFragsNext ; time to age frags yet? jns AgeFrags endif ; RFCC ret if RFCC AgeFrags: mov dx,cx add cx,5*18+1 ; check next in 5 seconds mov AgeFragsNext,cx push ds cli mov cx,Fraglist.lBufsAvail AgeLook4Buf: mov di,offset FragList call GetFromList assume ds:nothing jz AgeNoMoreFrags ; any reassembly buffers? mov si,offset FragList cmp dx,[bx].dTickTimeout ; too old? js AgePutBack ; - no, put it back call BufRelease ; - yes, release it SHOW_EVENT 'Q' jmp short AgeNextBuf AgePutBack: call AddToList AgeNextBuf: dec cl jnz AgeLook4Buf ; any more reassembly bufs? AgeNoMoreFrags: sti pop ds ret AgeNow: assume ds:code_s mov di,cx mov dx,cx add cx,2*18 ; chk next 2 seconds from now mov AgeNext,cx sub dx,70*18 ; clear what is older than 1 min mov cx,ARPSLOTS-3 mov si,offset ArpTabTr+6 cli 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? push si 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 if DEBUG ge 2 cmp ArpTabIp1[si],ax je AgeUnused SHOW_EVENT 'T' AgeUnused: endif ; DEBUG ge 2 mov ArpTabIp1[si],ax ; clear old entries mov ArpTabIp2[si],ax shl si,1 shl si,1 shl si,1 mov word ptr ArpTabHwAdr[si],ax mov word ptr ArpTabHwAdr[si+2],ax mov word ptr ArpTabHwAdr[si+4],ax pop si AgeArpYoung: loop AgeArpLoop sti add dx,10*18 ; need to age RoutTab sooner mov cx,ROUTESLOTS ; than ArpTab mov si,offset RouteTabTrRx cli 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 sti ret endif ; RFCC Ageing endp if RFCC ;************************************************************************ ;* 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 holeStruc ends HOLEDESCRLEN equ SIZE holeStruc k18 db 18 VerifyIpHdr proc near assume ds:nothing mov al,[di].iIpVerHlen and al,0f0h cmp al,040h ; IP version 4? jne VerifyErr1 mov ax,[bx].dPtrPhys call ArpFindHw ; find Hw Dst arp index mov [bx].dIdxHwDst,di ; 0 = bcast, 4 = me cmp di,ARPMYIDX ; is Hw addr to me or bcast? ja VerifyErr1 mov ax,[bx].dPtrPhys call ArpFindHwHl ; is Hw Src in arp table? jz VerifyChkBcast ; - yes cmp [bx].dIdxHwDst,ARPMYIDX ; - no. Addressed to me? jne VerifyIpDst ; mov di,[bx].dPtrIp ; - yes mov dx,[di].iIpSrc mov ax,[di].iIpSrc+2 call MyNetChk ; if he is on my net jnz VerifyIpDst call ArpPutNewSiHl ; add him to arp table jmp short VerifyIpDst VerifyChkIp: cmp cs:MyIpNr,0 ; do I know who I am? je VerifyIpUnknown VerifyErr1: jmp short VerifyErr VerifyChkBcast: cmp di,ARPMYIDX ; from me or broadcast? jbe VerifyErr ; - yes, ignore packet mov cx,cs:SavedTicks ; get current ticks value mov cs:ArpTabTr[di],cx VerifyIpDst: mov si,[bx].dPtrIp mov dx,[si].iIpDst ; check IP dst mov ax,[si].iIpDst+2 call ArpFindIp mov [bx].dIdxIpDst,di cmp di,ARPMYIDX ; is it to me or broadcast? ja VerifyChkIp ; - no, ignore packet VerifyIpUnknown: mov dx,[si].iIpSrc mov ax,[si].iIpSrc+2 call ArpFindIp ; check IP src addr jnz VerifyNoArp cmp di,ARPMYIDX ; from IP broadcast? jb VerifyErr ; -yes, ignore packet VerifyOK: mov di,[bx].dPtrIp test [di].iIpFlFrag,0ff3fh ; is this a fragment? jnz VerifyFrag clc ; - no, use as is VerifyRet: mov si,[bx].dPtrUdp ret VerifyNoArp: mov cl,[si].iIpTos call RouteFindCl ; is he in route table? jnz VerifyNoRoute mov cx,cs:SavedTicks mov cs:RouteTabTrRx[di],cx ; note we've got pkts from him VerifyNoRoute: jmp short VerifyOK FragAddAndErr: SHOW_EVENT 'Y' mov si,offset FragList push es call AddToList pop es VerifyFragErr: mov bx,bp push es pop ds VerifyErr: call BufRelease VerifyKeep: stc mov di,[bx].dPtrIp jmp short VerifyRet VerifyFrag: ; RFC 815 fragment reassembly: SHOW_EVENT 'R' mov bp,bx ; addr of fragment buffer push ds pop es mov dx,[di].iIpSrc ; get IP # / IP id / IP prot mov ax,[di].iIpSrc+2 mov si,[di].iIpId mov cx,cs:Fraglist.lBufsAvail mov ch,[di].iIpProt FragLook4Buf: mov di,offset FragList push es push si call GetFromList pop si pop es jz FragEarliest ; any reassembly buffers? SHOW_EVENT 'S' 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 push es call AddToList pop es pop si dec cl jnz FragLook4Buf FragEarliest: call FragFirstLast ; compute addr of fragment ja VerifyFragErr ; too big pkt? or ax,ax ; first part earliest? jnz FragOffset SHOW_EVENT 'U' mov bx,bp push es pop ds mov di,[bx].dPtrUdp add di,dx cmp [bx].dHomeList,offset FreeBufs ; and a big buffer? je FragFirstHole ; - yes, no extra buffer needed FragOffset: SHOW_EVENT 'V' push es call BufAlloc ; - no, create empty buffer pop es jz VerifyFragErr add di,HWHDRLEN ;*test mov [bx].dPtrIp,di mov si,es:[bp].dPtrIP mov cx,es:[bp].dPtrUdp ; copy IP header sub cx,si call MovesbEsToDs mov [bx].dPtrUdp,di FragFirstHole: mov [di].holeNext,0 ; create first hole descriptor mov [di].holeFirst,0 mov ax,cs:MyGiant mov [di].holeLast,ax mov [bx].dPtrFrag,di add di,HOLEDESCRLEN ; mark end of info mov [bx].dPktEnd,di FragBufFound: call FragFirstLast ; compute addr of fragment jbe $+5 jmp FragAddAndErr ; too big pkt? 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,es:[bp].dPtrIp ; 6. if frag.more test es:[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? jne FragDoCopy mov cx,es mov si,ds cmp cx,si je FragTimeUpd FragDoCopy: SHOW_EVENT 'W' or ax,ax ; if first frag jnz FragNotFirst SHOW_EVENT 'X' mov si,[bx].dPtrUdp ; retain this IP header mov di,es:[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 Movesb mov es:[bp].dPktEnd,di mov cx,[bx].dPtrFrag mov es:[bp].dPtrFrag,cx xchg bx,bp ; and switch buffers push ds push es pop ds pop es 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,es:[bp].dPtrUdp ; copy this frag to asm buf mov cx,dx sub cx,ax mov di,[bx].dPtrUdp add di,ax call MovesbEsToDs FragRelBuf: push bx ; release frag buf push ds mov bx,bp push es pop ds call BufRelease pop ds pop bx FragTimeUpd: push ds pop es mov cx,cs:SavedTicks ; update timer entry mov di,[bx].dPtrIp mov al,[di].iIpTtl mul cs: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 ret FragKeep: mov cx,cs:FreeBufs.lBufsAvail cmp cx,NBUFS/4 ; prevent starving jge FragKeep2 jmp VerifyErr FragKeep2: mov si,offset FragList ; keep buf a while call AddToList jmp VerifyKeep VerifyIpHdr endp ;************************************************************************ ;* FragFirstLast ;************************************************************************ FragFirstLast proc near mov di,es:[bp].dPtrIp ; compute frag.first mov ax,es:[di].iIpFlFrag xchg ah,al and ax,1fffh shl ax,1 shl ax,1 shl ax,1 mov dx,es:[di].iIpLen ; compute frag.last (+1) xchg dh,dl add dx,es:[bp].dPtrIp sub dx,es:[bp].dPtrUdp add dx,ax cmp dx,GIANTTR-IPHDRLEN-HWHDRLEN ; fits in buffer? ret ;*test GIANT FragFirstLast endp endif ; RFCC ;************************************************************************ ;* SwitchIpDst ;************************************************************************ GetIpSrc proc near mov si,[bx].dPtrIp ; get his IP # mov dx,[si].iIpSrc mov ax,[si].iIpSrc+2 ret GetIpSrc endp SwitchIpDst proc near ; mov his IP # to IP dst call GetIpSrc SetIpDst: mov di,[bx].dPtrIp mov [di].iIpDst,dx ; set IP dst mov [di].iIpDst+2,ax ret SwitchIpDst endp ;************************************************************************ ;* MakeMynet ;************************************************************************ MakeMynet proc near assume ds:code_s mov dx,MyIpNr mov ax,MyIpNr+2 mov ArpTabIp1+ARPMYIDX,dx ; third arp slot = me mov ArpTabIp2+ARPMYIDX,ax 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 push es assume ds:code_s mov dx,MyIpNr mov ax,MyIpNr+2 push ds call BufAlloc assume ds:nothing mov [bx].dTimOutMsg,0 ; we SHOULD get no answer mov [bx].dTickTimeout,10 ; give them half a second call SendArpReq ; send arp to our Ip # call BufRelease pop ds assume ds:code_s pop es 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 al,09 ; error code 9 call PrTerminate ValidateIpNr endp ;************************************************************************ ;* DoBootpPkt ;************************************************************************ DoBootpPkt proc near assume ds:code_s push ds call BufAlloc ; get a buffer call MakeSendDescr push di ; preclear udp hdr and data xor ax,ax mov cx,(BPDATALEN+ICMPHDRLEN)/2 rep stosw pop di mov [di].uUdpSrc,4400h ; udp hdr info mov [di].uUdpDst,4300h mov [di].uBotOp,1 ; bootp info mov al,byte ptr ArpBuf.iArpHtype+1 mov [di].uBotHtype,al ; put my HW type mov [di].uBotMagNum,8263h mov [di].uBotMagNum+2,6353h mov ax,BootpXid mov [di].uBotXid,ax mov cx,Hlen mov [di].uBotHlen,cl mov si,offset MyHwAd lea di,[di].uBotCliHwAd rep movsb ; copy my HW addr xor ax,ax ; IP hdr info mov si,[bx].dPtrIp dec ax mov [si].iIpDst,ax mov [si].iIpDst+2,ax mov [bx].dWaitEvent,GOT_BOOTP ; event to wait for mov [bx].dTimOutMsg,offset NoBotReplyMsg ; error msg mov ax,BPDATALEN+UDPHDRLEN ; bootp pkt length mov [bx].dPktLen,ax call SendUdpPkt ; send bootp request call BufRelease push cs pop es pop ds ret DoBootpPkt endp ;************************************************************************ ;* InterpBootp according to RFC 1084 and RFC1048 ;************************************************************************ InterpBootp proc near assume ds:code_s or Flagword,HAVE_MYIPNR ; note what we've got push es push ds lds bx,AdrBootpReply assume ds:nothing mov di,[bx].dPtrUdp mov dx,[di].uBotYourIp ; save my IP # mov cs:MyIpNr,dx mov ax,[di].uBotYourIp+2 mov cs:MyIpNr+2,ax 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 pop ds pop es ret VendNext: lodsb ; get field type: or al,al ; filler jz 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 cs:Flagword,HAVE_TIMEOFFSET jnz VendDefault mov di,offset tzoffset call Xtract4Bytes or cs:Flagword,HAVE_TIMEOFFSET jmp short VendLoop NotTimeOffs: cmp al,3 ; default gateways jne NotDefGwys mov di,offset DefGwys mov cx,MAXDEFGWYS mov ax,cs:DefGwyNum call XtractIpNums add cs:DefGwyNum,cx jmp short VendLoop NotDefGwys: cmp al,4 ; time servers jne NotTimeserv or cs:Flagword,HAVE_TIMESERVER mov di,offset TimeServIpNr mov cx,MAXTSERVS mov ax,cs:TservNum call XtractIpNums add cs: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,cs:DefNSnum call XtractIpNums add cs:DefNSnum,cx jmp VendLoop NotDefNS: endif ; TBLBUILD or PINGCLIENT cmp al,0ffh ; end jne VendDefault jmp VendEnd VendDefault: ; everything else lodsb xor ah,ah add si,ax ; skip field jmp Vendloop InterpBootp endp ;************************************************************************ ;* XtractIpNums ;************************************************************************ XtractIpNums proc near assume ds:nothing 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 if TBLBUILD or PINGCLIENT NsStruc struc uNsUdpHdr UdpStruc <> uNsId dw 0 uNsOpwd dw 0001h ; do recursion uNsQdcount dw 0100h ; one question uNsAncount dw 0 uNsNscount dw 0 uNsArcount dw 0 uNsQuest equ $-uNsUdpHdr NsStruc ends ;************************************************************************ ;* NameDecode ;* ;* Find end of name and change length bytes to dots ;************************************************************************ NameDecode proc near assume ds:nothing lodsb mov byte ptr [si-1],' ' ; blank 1st length byte jmp short NameDcTst NameDcLoop: lodsb mov byte ptr [si-1],'.' ; change length byte to dot NameDcTst: cmp al,0c0h ; compressed? jb NameDcNorm mov byte ptr [si],' ' inc si ret NameDcNorm: mov ah,al or al,al ; end of name? jz NameDcRet ; -yes, return NameDcSkip: lodsb ; -no, skip over string or al,al ; bad syntax? jz NameDcRet ; -yes, better return now dec ah ; -no, continue skiping jnz NameDcSkip jmp short NameDcLoop NameDcRet: ret NameDecode endp ;************************************************************************ ;* NsResolve ;* ;* Input: DX = my udp port ;* AX = Ns Id ;* CS:SI = address of querry string ;************************************************************************ MsgResolve db "no response.$" NsResolve proc near assume ds:nothing push es push bx push ds push si call BufAlloc ; get a big buf pop si mov cx,SERRNOBUF jz NsResErr call MakeSendDescr mov [di].uUdpDst,3500h mov [di].uUdpSrc,dx mov [di].uNsId,ax xor ax,ax mov [di].uNsOpwd,1 ; recursion desired mov [di].uNsQdcount,0100h ; 1 question mov [di].uNsAncount,ax mov [di].uNsNscount,ax mov [di].uNsArcount,ax mov [bx].dTick2Timeout,14*18 ; give him 14 seconds 2nd turn mov [bx].dTimOut2Msg,ax mov [bx].dWaitEvent,GOT_NSREPLY cmp dx,1234h je NsTableBuild mov [bx].dTickResend,4*18 ; resend after 4 seconds mov [bx].dTickTimeout,2*18 ; give him 2 seconds 1st turn mov [bx].dTimOut2Msg,offset MsgResolve NsTableBuild: lea di,[di].uNsQuest ; copy question NsQloop: lods byte ptr cs:[EchoNameBuf] stosb or al,al jnz NsQloop movs word ptr es:[uNsQuest],word ptr cs:[EchoNameBuf] ; copy type movs word ptr es:[uNsQuest],word ptr cs:[EchoNameBuf] ; and class mov ax,di ; compute ip data length mov si,[bx].dPtrUdp sub ax,si mov [bx].dPktLen,ax SHOW_EVENT 'I' mov dx,offset DefNsNum call SendUdpFind ; send pkt call BufRelease SHOW_EVENT 'J' NsResErr: or cx,cx pop ds pop bx pop es ret NsResolve endp ;************************************************************************ ;* DoNsInterp ;************************************************************************ DoNsInterp proc near assume ds:nothing cld push cs pop es mov di,[bx].dPtrUdp test [di].uNsOpwd,0080h ; reply? jnz NameResReply ret NameResReply: if TBLBUILD cmp [di].uUdpDst,1234h ; to the tblbuilder? jne DoNsIntPing jmp DoName endif ; TBLBUILD DoNsIntPing: mov cx,[di].uNsAncount xchg ch,cl cmp cx,1 ; any answers? jb NameResNoAnswer lea si,[di].uNsQuest call NameDecode ; decode question string add si,4 ; skip over type and class NsAnsLoop: call NameDecode ; decode answer string mov ax,[si] ; get type add si,9 ; skip over junk cmp ax,0100h ; address? je NsAnsAddr lodsb xor ah,ah add si,ax ; skip over data bytes loop NsAnsLoop jmp short NameResNoAnswer NsAnsAddr: cmp byte ptr [si],4 ; 4 IP bytes here? jne NameResNoAnswer inc si ; copy IP number push cs pop es mov di,offset EchoTarget movsw movsw NameResNoAnswer: or cs:Events,GOT_NSREPLY ; note we've got ns reply ret DoNsInterp endp endif ; TBLBUILD or PINGCLIENT ;************************************************************************ ;* ARP and IP receiver ;************************************************************************ assume ds:nothing Receiver: pushf push ds ; save segment register cld if DEBUG test cs:GenFlags,DBGSTOP jnz IpRecTooBig endif ; DEBUG or ax,ax ; first or second call? jne IpRecv_1 ; - second, we've got data ; - first, they want a buf SHOW_EVENT 'A' cmp cx,cs:MyGiant ; packet too long? ja IpRecTooBig if PINGCLIENT ifdef SMALLBUFS cmp cx,BUFBODYSML ja IpRecBig call BufAlSml jz IpRecBig pop ds popf retf IpRecBig: endif ; SMALLBUFS endif ; PINGCLIENT call BufAlloc ; get a receive buffer jz IpRecNoBuf IpRecRet0: pop ds popf retf ; return to pkt drvr if DEBUG DbgIpRecv: or cs:GenFlags,DBGINTERR endif ; DEBUG IpRecNoBuf: if PINGCLIENT cmp bx,cs:IpHandle jne IpRecTooBig inc cs:EchoDrop endif ; PINGCLIENT IpRecTooBig: xor di,di ; no buffer available mov es,di jmp short IpRecRet0 IpRecv_1: mov word ptr cs:SaveSS,ss ; switch to our mov word ptr cs:SaveSP,sp ; interrupt stack cli mov ss,cs:MySegm mov sp,offset StackEnd sti ; allow interrupts if DEBUG ge 2 mov dx,ds cmp dx,cs:MySegm je IpRecvCs SHOW_EVENT 'B' IprecvCs: endif ; DEBUG ge 2 if DEBUG dec cs:DbgIntCnt ; double interrupt? jnz DbgIpRecv endif ; DEBUG if PINGCLIENT mov ax,cx ; pkt length add ax,8+4+12 ; preamble, crc, intergap add cs:EchoLoad+2,ax adc cs:EchoLoad,0 endif ; PINGCLIENT mov ax,si add ax,cx ; end of packet limit mov bx,[si-2] ; addr of descriptor mov [bx].dPktLen,cx ; fill in descriptor info mov [bx].dPktEnd,ax add si,cs:H2Len mov ax,[si] ; type/length field xchg ah,al xor dl,dl cmp ax,GIANT ; if 802.3 pkt jbe BuildSnap ; do special handling BuildNotSnap: mov [bx].dSnap,dl lea di,[si+2] mov [bx].dPtrIp,di ; di must point to IP hdr cmp ax,0806h ; ARP protocol? je ArpRecvCont0 mov cl,[di].iIpVerHlen ; get version+length byte and cx,0fh ; length (32 bit words) shl cx,1 ; convert to shl cx,1 ; byte length 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 SHOW_EVENT 'H' 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 mov al,[di].iIpProt cmp al,ICMP_PROT ; ICMP protocol? jne IpNotIcmp jmp IpRecIcmp BuildSnap: inc dl ; -no, assumed to be snap add si,SNAPLEN ; skip over snap bytes jmp short BuildNotSnap ArpRecvCont0: cmp [di].iArpProt,0008h ; arp IP protocol? jne IpRecRet jmp ArpRecvCont IpNotIcmp: cmp al,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: SHOW_EVENT 'Z' call BufRelease ; release receive buffer IPRecKeepBuf: if DEBUG ge 2 cmp sp,offset StackEnd call TstEqual endif ; DEBUG ge 2 if DEBUG inc cs:DbgIntCnt endif ; DEBUG cli ; restore previous stack mov ss, word ptr cs:SaveSS mov sp, word ptr cs:SaveSP pop ds popf retf ; return to pkt drvr if TBLBUILD ArpRecBld0: jmp ArpRecBld endif ; TBLBUILD IpProtUnr: mov ah,2 ; protocol unreachable jmp short IpUnr IpPortUnr: mov ah,3 ; port unreachable IpUnr: if RFCC mov al,3 ; destination unreachable cmp [bx].dIdxIpDst,ARPMYIDX ; was it specifically to me? if TBLBUILD jne ArpRecBld0 ; -no, collect his address else jne IpRecRet endif ; TBLBUILD push bx push ds push ax call GetIpSrc ; -yes, mov his IP # to IP dst mov cx,[bx].dPtrUdp ; copy IP header add cx,8 ; + 8 bytes sub cx,si push si call BufAlloc pop si jz UnrEnd call MakeSendDescr push di call SetIpDst ; return to sender pop di pop ax mov [di].uIcmpTypecode,ax ; set type and code pop es push es push ax add di,8 call MovesbEsToDs mov si,[bx].dPtrUdp sub di,si mov [bx].dPktLen,di ; set IP data length mov si,offset IcmpToDo ; put buf on the ICMP send list call AddToList UnrEnd: pop ax pop ds pop bx endif ; RFCC IpRecRet3: jmp IpRecRet IpRecUdp: ; ------------- UDP -------------------- mov [bx].dPktEnd,si ; end of logical pkt mov di,[bx].dPtrUdp mov ax,word ptr [di].uUdpSrc mov dx,word ptr [di].uUdpDst if TBLBUILD or PINGCLIENT cmp dx,0703h ; Udp Echo reply? jne $+5 jmp IpEchoReply cmp dx,0700h ; Udp Echo request? jne $+5 jmp IpEchoRequest cmp dx,0900h ; Udp Discard request? jne $+5 jmp IpDiscard cmp ax,3500h ; Name server (53)? jne $+5 jmp IpRecvName endif ; TBLBUILD or PINGCLIENT cmp ax,2500h ; Src port 0025 = 37 ? je IpRecvTime ; - must be time reply if 0 cmp ax,4300h ; Src port 0043 = 67 jne IpPortUnr endif cmp dx,4400h ; Dst port 0044 = 68 jne IpPortUnr cmp byte ptr [di].uBotOp,2 ; bootp reply? jne IpRecRet3 IpRecBootp: ; ------------- UDP BOOTP REPLY ------------------- push cs pop es push di ; - must be bootp reply lea si,[di].uBotCliHwAd mov di,offset MyHwAd mov cx,cs:Hlen repe cmpsb ; our Ethernet addr? pop di jne IpRecRet2 mov cx,cs:BootpXid cmp cx,[di].uBotXid jne IpRecRet2 ; yes, it's about me! mov dx,[di].uBotGwyIp ; saves an ARP request mov ax,[di].uBotGwyIp+2 ; in many cases call ArpPutNewSiHl test cs:Events,GOT_BOOTP ; if first answer jnz IpRecRet2 ; save bootp answer mov cs:AdrBootpReply.offs,bx ; for further study mov cs:AdrBootpReply.segm,ds or cs:Events,GOT_BOOTP jmp IpRecKeepBuf IpRecvTime: ; ------------- UDP TIME REPLY -------------------- test cs:Events,GOT_TIMEREPLY ; already got reply? jnz IpRecRet2 mov ax,[di].uUdpData ; save seconds mov cs:cTime,ax ; since year 1900 mov ax,[di].uUdpData+2 mov cs:cTime+2,ax mov di,[bx].dPtrIp ; save who was answering mov dx,[di].iIpSrc mov ax,[di].iIpSrc+2 mov cs:RespondingIpNr,dx mov cs:RespondingIpNr+2,ax or cs:Events,GOT_TIMEREPLY IpRecRet2: jmp IpRecRet if TBLBUILD or PINGCLIENT IpRecvName: ; ------------- UDP NAME REPLY ----------------- SHOW_EVENT 'K' mov si,offset NameToDo ; process nameserver reply call AddToList jmp IpRecKeepBuf endif ; TBLBUILD or PINGCLIENT if RFCC IpEchoRequest: ; ------------- UDP ECHO REQ ---------------- call SwitchIpDst mov si,[bx].dPtrUdp mov dx,[si].uUdpDst ; swap udp src and dst ports mov ax,[si].uUdpSrc mov [si].uUdpDst,ax mov [si].uUdpSrc,dx jmp IpQueReply IpDiscard: ; ------------- UDP DISCARD ------------------ cmp cs:EchoTarget,0 jne IpRecRet4 add cs:EchoRxLo,1 ; increment receive counters adc cs:EchoRxHi,0 IpRecRet4: jmp IpRecRet endif ; RFCC IpRecIcmp: ; ------------- ICMP -------------------------------- call IcmpChkSum2 ; valid ICMP checksum? jne IpRecRet2 mov cx,[di].uIcmpTypecode ; get type and code if PINGCLIENT cmp cl,0 ; echo reply? jne IpNotEchoReply IpEchoReply: ; ------------- ICMP PING REPLY ------------ SHOW_EVENT 'L' call EchoCalc mov ds,cx ; restore ds for buf rel jmp IpRecRet IpNotEchoReply: endif ; PINGCLIENT call SwitchIpDst ; in case we want to return it mov si,[bx].dPtrUdp ; point to ICMP header if RFCC cmp cl,8 ; echo request? jne IpNotEchoReq ; --------------- ICMP PING REQ --------------- SHOW_EVENT 'M' mov byte ptr [si].uIcmpTypecode,0 ; put echo reply value IpQueReply: cmp [bx].dIdxIpDst,ARPMYIDX ; broadcast? jb IpRecRet4 ; - yes, don't echo test cs:ArgFlags,UPCALL_SEND ; want to stress the driver? jnz IpUpcallSend mov si,offset IcmpToDo ; put buf on the ICMP send list call AddToList jmp IpRecKeepBuf IpUpcallSend: mov di,[bx].dPtrIp cmp [di].iIpProt,UDP_PROT ; UDP protocol? je IpUdp2Do call SendIcmpPkt jmp short IpRecRet5 IpUdp2Do: mov [bx].dWaitEvent,0 ; don't wait for answer call SendUdpPkt IpRecRet5: jmp IpRecRet IpNotEchoReq: endif ; RFCC mov dx,[si].uIcmpIpHdr.iIpDst ; get original IP hdr mov ax,[si].uIcmpIpHdr.iIpDst+2 ; dst IP # cmp cx,11 ; TTL exceeded? je IpIcmpUnreach cmp cl,3 ; unreachable jne IpNotUnreach ; --------------- ICMP UNREACHABLE --------- 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 SHOW_EVENT 'N' push si call RouteFindUtos ; 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 cs:RouteTabUnreach[di],ax ; mark it unreachable mov cx,cs:SavedTicks ; get current ticks value mov cs:RouteTabTrRx[di],cx ; set timer IpIcmpUnfound: IpIcmpRet2: jmp IpIcmpRet IpNotUnreach: if RFCC cmp cl,4 ; source quench? jne IpIcmpNotQuench ; --------------- ICMP SRC QUENCH ---------- SHOW_EVENT 'O' call RouteFindUtos ; this host in route table? push ds push cs pop ds 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 mov cx,SavedTicks mov [si],cx ; initialize sq timer mov ax,100 ; initial sq delay 100 ms IpIcmpAddDelay: add ax,28 ; increase delay by 28 ms test dx,SQ_UPDATED ; unless already done in jnz IpIcmpSqEnd ; the last two seconds mov [di],ax IpIcmpSqEnd: pop ds jmp short IpIcmpRet IpIcmpNotQuench: endif ; RFCC cmp cl,5 ; redirect? jne IpNotRedirect ; --------------- ICMP REDIRECT ------------ SHOW_EVENT 'P' push si call RouteFindUtos ; this host in route table? pop si jnz IpIcmpDisfound mov dx,cs:RouteTabIpG1[di] ; icmp from the gwy used? mov ax,cs: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 cs:RouteTabIpG1[di],dx ; put it into route table mov cs:RouteTabIpG2[di],ax IpIcmpDisfound: jmp short IpIcmpRet IpNotRedirect: IpIcmpRet: jmp IpRecRet ;======================================================================== ; endinclude