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add libip

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This commit is contained in:
rsc 2003-11-23 18:23:20 +00:00
parent 99947423b1
commit d709423926
13 changed files with 875 additions and 0 deletions
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68
src/libip/ptclbsum.c Normal file
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#include <u.h>
#include <libc.h>
#include <ip.h>
static short endian = 1;
static uchar* aendian = (uchar*)&endian;
#define LITTLE *aendian
ushort
ptclbsum(uchar *addr, int len)
{
ulong losum, hisum, mdsum, x;
ulong t1, t2;
losum = 0;
hisum = 0;
mdsum = 0;
x = 0;
if((ulong)addr & 1) {
if(len) {
hisum += addr[0];
len--;
addr++;
}
x = 1;
}
while(len >= 16) {
t1 = *(ushort*)(addr+0);
t2 = *(ushort*)(addr+2); mdsum += t1;
t1 = *(ushort*)(addr+4); mdsum += t2;
t2 = *(ushort*)(addr+6); mdsum += t1;
t1 = *(ushort*)(addr+8); mdsum += t2;
t2 = *(ushort*)(addr+10); mdsum += t1;
t1 = *(ushort*)(addr+12); mdsum += t2;
t2 = *(ushort*)(addr+14); mdsum += t1;
mdsum += t2;
len -= 16;
addr += 16;
}
while(len >= 2) {
mdsum += *(ushort*)addr;
len -= 2;
addr += 2;
}
if(x) {
if(len)
losum += addr[0];
if(LITTLE)
losum += mdsum;
else
hisum += mdsum;
} else {
if(len)
hisum += addr[0];
if(LITTLE)
hisum += mdsum;
else
losum += mdsum;
}
losum += hisum >> 8;
losum += (hisum & 0xff) << 8;
while(hisum = losum>>16)
losum = hisum + (losum & 0xffff);
return losum & 0xffff;
}