diff options
Diffstat (limited to 'lib/libpcap/libpcap/msdos/pkt_rx1.s')
| -rw-r--r-- | lib/libpcap/libpcap/msdos/pkt_rx1.s | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/lib/libpcap/libpcap/msdos/pkt_rx1.s b/lib/libpcap/libpcap/msdos/pkt_rx1.s new file mode 100644 index 0000000..654e657 --- /dev/null +++ b/lib/libpcap/libpcap/msdos/pkt_rx1.s @@ -0,0 +1,155 @@ +; +; This file requires NASM 0.97+ to assemble +; +; Currently used only for djgpp + DOS4GW targets +; +; these sizes MUST be equal to the sizes in PKTDRVR.H +; +%define ETH_MTU 1500 ; max data size on Ethernet +%define ETH_MIN 60 ; min/max total frame size +%define ETH_MAX (ETH_MTU+2*6+2) ; =1514 +%define NUM_RX_BUF 32 ; # of RX element buffers +%define RX_SIZE (ETH_MAX+6) ; sizeof(RX_ELEMENT) = 1514+6 +%idefine offset + +struc RX_ELEMENT + .firstCount resw 1 ; # of bytes on 1st call + .secondCount resw 1 ; # of bytes on 2nd call + .handle resw 1 ; handle for upcall + ; .timeStamp resw 4 ; 64-bit RDTSC value + .destinAdr resb 6 ; packet destination address + .sourceAdr resb 6 ; packet source address + .protocol resw 1 ; packet protocol number + .rxBuffer resb ETH_MTU ; RX buffer +endstruc + +;------------------------------------------- + +[org 0] ; assemble to .bin file + +_rxOutOfs dw offset _pktRxBuf ; ring buffer offsets +_rxInOfs dw offset _pktRxBuf ; into _pktRxBuf +_pktDrop dw 0,0 ; packet drop counter +_pktTemp resb 20 ; temp work area +_pktTxBuf resb (ETH_MAX) ; TX buffer +_pktRxBuf resb (RX_SIZE*NUM_RX_BUF) ; RX structures + LAST_OFS equ $ + +screenSeg dw 0B800h +newInOffset dw 0 + +fanChars db '-\|/' +fanIndex dw 0 + +%macro SHOW_RX 0 + push es + push bx + mov bx, [screenSeg] + mov es, bx ;; r-mode segment of colour screen + mov di, 158 ;; upper right corner - 1 + mov bx, [fanIndex] + mov al, [fanChars+bx] ;; get write char + mov ah, 15 ;; and white colour + cld ;; Needed? + stosw ;; write to screen at ES:EDI + inc word [fanIndex] ;; update next index + and word [fanIndex], 3 + pop bx + pop es +%endmacro + +;PutTimeStamp +; rdtsc +; mov [si].timeStamp, eax +; mov [si+4].timeStamp, edx +; ret + + +;------------------------------------------------------------------------ +; +; This routine gets called by the packet driver twice: +; 1st time (AX=0) it requests an address where to put the packet +; +; 2nd time (AX=1) the packet has been copied to this location (DS:SI) +; BX has client handle (stored in RX_ELEMENT.handle). +; CX has # of bytes in packet on both call. They should be equal. +; A test for equality is done by putting CX in _pktRxBuf [n].firstCount +; and _pktRxBuf[n].secondCount, and CL on first call in +; _pktRxBuf[n].rxBuffer[CX]. These values are checked in "PktReceive" +; (PKTDRVR.C) +; +;--------------------------------------------------------------------- + +_PktReceiver: + pushf + cli ; no distraction wanted ! + push ds + push bx + mov bx, cs + mov ds, bx + mov es, bx ; ES = DS = CS or seg _DATA + pop bx ; restore handle + + cmp ax, 0 ; first call? (AX=0) + jne @post ; AX=1: second call, do post process + +%ifdef DEBUG + SHOW_RX ; show that a packet is received +%endif + + cmp cx, ETH_MAX ; size OK ? + ja @skip ; no, too big + + mov ax, [_rxInOfs] + add ax, RX_SIZE + cmp ax, LAST_OFS + jb @noWrap + mov ax, offset _pktRxBuf +@noWrap: + cmp ax, [_rxOutOfs] + je @dump + mov di, [_rxInOfs] ; ES:DI -> _pktRxBuf[n] + mov [newInOffset], ax + + mov [di], cx ; remember firstCount. + mov [di+4], bx ; remember handle. + add di, 6 ; ES:DI -> _pktRxBuf[n].destinAdr + pop ds + popf + retf ; far return to driver with ES:DI + +@dump: add word [_pktDrop+0], 1 ; discard the packet on 1st call + adc word [_pktDrop+2], 0 ; increment packets lost + +@skip: xor di, di ; return ES:DI = NIL pointer + xor ax, ax + mov es, ax + pop ds + popf + retf + +@post: or si, si ; DS:SI->_pktRxBuf[n][n].destinAdr + jz @discard ; make sure we don't use NULL-pointer + + ; + ; push si + ; call bpf_filter_match ; run the filter here some day + ; pop si + ; cmp ax, 0 + ; je @discard + + mov [si-6+2], cx ; store _pktRxBuf[n].secondCount + mov ax, [newInOffset] + mov [_rxInOfs], ax ; update _pktRxBuf input offset + + ; call PutTimeStamp + +@discard: + pop ds + popf + retf + +_pktRxEnd db 0 ; marker for end of r-mode code/data + +END + |