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bkamen
Joined: 07 Jan 2004
Posts: 1611
Location: Central Illinois, USA
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| Nasty Bug in MCHP TCP/IP 3.75 Drivers (CCS Friendly) |
 Posted: Wed Oct 14, 2009 2:26 am |
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I just found an icky bug I'd like anyone to confirm out there for me.
in the tcpip/helpers.c:
| Code: | WORD CalcIPChecksum(BYTE* buffer, WORD count)
{
WORD i, y,z;
WORD *val;
WORD temp;
union
{
DWORD Val;
struct
{
WORD_VAL LSB;
WORD_VAL MSB;
} w;
} sum;
sum.Val = 0;
i = count >> 1;
val = (WORD*)buffer;
// Calculate the sum of all words
while(i--)
sum.Val += (DWORD)*val++;
// Add in the sum of the remaining byte, if present
#warning "Fixed: 'if(((WORD_VAL*)&count) & 1)' to 'if( count & 1)' - BEN"
if( count & 1)
sum.Val += (DWORD)*(BYTE*)val;
// Do an end-around carry (one's complement arrithmatic)
sum.Val = (DWORD)sum.w.LSB + (DWORD)sum.w.MSB;
// Do another end-around carry in case if the prior add
// caused a carry out
y = sum.w.LSB;
z = sum.w.MSB;
y += z;
// Return the resulting checksum
return (~y);
} |
Look to see if you have if( ((WORD_VAL*) &count) & 1).
The author really just wanted to test count for being odd (not even) and ends up with the address of count.
Depending on the RAM location the compiler assigns it, you can either be working or not...
When I used my PICDEM.net2 with the built-in ethernet, no problem. When I switched to the onboard ENC28J60, it would fail checksums.
So fix away and let me know if this solved a problem for you.
-Ben[/u]
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D |
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andrewg
Joined: 17 Aug 2005
Posts: 316
Location: Perth, Western Australia
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| Posted: Wed Oct 14, 2009 10:48 am |
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The v3.75 CCS port has "count & 1" already.
_________________
Andrew |
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bkamen
Joined: 07 Jan 2004
Posts: 1611
Location: Central Illinois, USA
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| Posted: Wed Oct 14, 2009 2:19 pm |
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That's bizarre since I'm using the CCS port(!).
I double checked the code from the install directory. (I made a copy of the source before starting my project.)
Anyone else?
-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Oct 14, 2009 2:31 pm |
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Download CCS TCP/IP package on this page (requires current maintenance):
http://www.ccsinfo.com/compilerupdates.php
Install, and run Examine32 (or other text search engine) on this directory:
| Quote: | | c:\program files\picc\tcp-ip |
Search for this text:
Use this filespec:
Get these hits:
| Quote: | c:\program files\picc\tcp-ip\pic examples source\drivers\helpers.c 5/24/04 12:36:22 PM 3945
int16 CalcIPChecksum(int8* buff, int16 count)
{
.
.
.
if ( count & 1 )
sum.Val += *(int8 *)val;
.
.
}
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| Quote: | c:\program files\picc\tcp-ip\pic examples source\tcpip\helpers.c 10/24/06 4:20:00 PM 7283
WORD CalcIPChecksum(BYTE* buffer, WORD count)
{
.
.
.
if ( count & 1 )
sum.Val += *(BYTE *)val;
.
.
. |
Version information from the above file:
| Quote: |
* Darren Rook (CCS) 10/24/06 In synch with Microchip's V3.75 stack |
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bkamen
Joined: 07 Jan 2004
Posts: 1611
Location: Central Illinois, USA
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| Posted: Wed Oct 14, 2009 3:41 pm |
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Wow.
Wow.
I swear I'm not a rabid user of mind enhancers. I pop a centrum complete a day and that's it.
This file is a copy of the CCS TCP source which when I look at the install tree I find the same things you are finding.
The whole CalcIPChecksum routine looks different.
It's official. I have no idea where this version of helpers.c came from.
Not microchip. Not CCS.
I blame my computer. It runs Windoze and Bill is the root of all things eeeevviiiill. That's gotta be it.
Thanks for the verification everyone,
-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D |
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