nexmon – Blame information for rev 1

Subversion Repositories:
Rev:
Rev Author Line No. Line
1 office 1 ;
2 ; This file requires NASM 0.97+ to assemble
3 ;
4 ; Currently used only for djgpp + DOS4GW targets
5 ;
6 ; these sizes MUST be equal to the sizes in PKTDRVR.H
7 ;
8 %define ETH_MTU 1500 ; max data size on Ethernet
9 %define ETH_MIN 60 ; min/max total frame size
10 %define ETH_MAX (ETH_MTU+2*6+2)
11 %define NUM_RX_BUF 32 ; # of RX element buffers
12 %define RX_SIZE (ETH_MAX+6) ; sizeof(RX_ELEMENT) = 1514+6
13 %idefine offset
14  
15 struc RX_ELEMENT
16 .firstCount resw 1 ; # of bytes on 1st call
17 .secondCount resw 1 ; # of bytes on 2nd call
18 .handle resw 1 ; handle for upcall
19 ; .timeStamp resw 4 ; 64-bit RDTSC value
20 .destinAdr resb 6 ; packet destination address
21 .sourceAdr resb 6 ; packet source address
22 .protocol resw 1 ; packet protocol number
23 .rxBuffer resb ETH_MTU ; RX buffer
24 endstruc
25  
26 ;-------------------------------------------
27  
28 [org 0] ; assemble to .bin file
29  
30 _rxOutOfs dw offset _pktRxBuf ; ring buffer offsets
31 _rxInOfs dw offset _pktRxBuf ; into _pktRxBuf
32 _pktDrop dw 0,0 ; packet drop counter
33 _pktTemp resb 20 ; temp work area
34 _pktTxBuf resb (ETH_MAX) ; TX buffer
35 _pktRxBuf resb (RX_SIZE*NUM_RX_BUF) ; RX structures
36 LAST_OFS equ $
37  
38 screenSeg dw 0B800h
39 newInOffset dw 0
40  
41 fanChars db '-\|/'
42 fanIndex dw 0
43  
44 %macro SHOW_RX 0
45 push es
46 push bx
47 mov bx, [screenSeg]
48 mov es, bx ;; r-mode segment of colour screen
49 mov di, 158 ;; upper right corner - 1
50 mov bx, [fanIndex]
51 mov al, [fanChars+bx] ;; get write char
52 mov ah, 15 ;; and white colour
53 cld ;; Needed?
54 stosw ;; write to screen at ES:EDI
55 inc word [fanIndex] ;; update next index
56 and word [fanIndex], 3
57 pop bx
58 pop es
59 %endmacro
60  
61 ;PutTimeStamp
62 ; rdtsc
63 ; mov [si].timeStamp, eax
64 ; mov [si+4].timeStamp, edx
65 ; ret
66  
67  
68 ;------------------------------------------------------------------------
69 ;
70 ; This routine gets called by the packet driver twice:
71 ; 1st time (AX=0) it requests an address where to put the packet
72 ;
73 ; 2nd time (AX=1) the packet has been copied to this location (DS:SI)
74 ; BX has client handle (stored in RX_ELEMENT.handle).
75 ; CX has # of bytes in packet on both call. They should be equal.
76 ; A test for equality is done by putting CX in _pktRxBuf [n].firstCount
77 ; and _pktRxBuf[n].secondCount, and CL on first call in
78 ; _pktRxBuf[n].rxBuffer[CX]. These values are checked in "PktReceive"
79 ; (PKTDRVR.C)
80 ;
81 ;---------------------------------------------------------------------
82  
83 _PktReceiver:
84 pushf
85 cli ; no distraction wanted !
86 push ds
87 push bx
88 mov bx, cs
89 mov ds, bx
90 mov es, bx ; ES = DS = CS or seg _DATA
91 pop bx ; restore handle
92  
93 cmp ax, 0 ; first call? (AX=0)
94 jne @post ; AX=1: second call, do post process
95  
96 %ifdef DEBUG
97 SHOW_RX ; show that a packet is received
98 %endif
99  
100 cmp cx, ETH_MAX ; size OK ?
101 ja @skip ; no, too big
102  
103 mov ax, [_rxInOfs]
104 add ax, RX_SIZE
105 cmp ax, LAST_OFS
106 jb @noWrap
107 mov ax, offset _pktRxBuf
108 @noWrap:
109 cmp ax, [_rxOutOfs]
110 je @dump
111 mov di, [_rxInOfs] ; ES:DI -> _pktRxBuf[n]
112 mov [newInOffset], ax
113  
114 mov [di], cx ; remember firstCount.
115 mov [di+4], bx ; remember handle.
116 add di, 6 ; ES:DI -> _pktRxBuf[n].destinAdr
117 pop ds
118 popf
119 retf ; far return to driver with ES:DI
120  
121 @dump: add word [_pktDrop+0], 1 ; discard the packet on 1st call
122 adc word [_pktDrop+2], 0 ; increment packets lost
123  
124 @skip: xor di, di ; return ES:DI = NIL pointer
125 xor ax, ax
126 mov es, ax
127 pop ds
128 popf
129 retf
130  
131 @post: or si, si ; DS:SI->_pktRxBuf[n][n].destinAdr
132 jz @discard ; make sure we don't use NULL-pointer
133  
134 ;
135 ; push si
136 ; call bpf_filter_match ; run the filter here some day
137 ; pop si
138 ; cmp ax, 0
139 ; je @discard
140  
141 mov [si-6+2], cx ; store _pktRxBuf[n].secondCount
142 mov ax, [newInOffset]
143 mov [_rxInOfs], ax ; update _pktRxBuf input offset
144  
145 ; call PutTimeStamp
146  
147 @discard:
148 pop ds
149 popf
150 retf
151  
152 _pktRxEnd db 0 ; marker for end of r-mode code/data
153  
154 END
155