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Fix for mbufs that start on odd-byte-aligned boundaries, and use.

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jonathan 1997-08-12 06:05:28 +00:00
parent 73596f5504
commit a5266cdd64
2 changed files with 35 additions and 10 deletions
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2
sys/arch/mips/conf/files.mips
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@ -11,5 +11,5 @@ file arch/mips/mips/mips_machdep.c # shared mips machdep.c
file arch/mips/mips/sys_machdep.c # shared mips sys_machdep
file arch/mips/mips/process_machdep.c # shared process_machdep
file netinet/in_cksum.c inet
file arch/mips/mips/in_cksum.c inet
file netns/ns_cksum.c ns

43
sys/arch/mips/mips/in_cksum.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: in_cksum.c,v 1.2 1997/07/22 07:36:18 jonathan Exp $ */
/* $NetBSD: in_cksum.c,v 1.3 1997/08/12 06:05:28 jonathan Exp $ */
/*
* Copyright (c) 1993 Regents of the University of California.
@ -35,6 +35,10 @@
* 15% faster than version 1 ("Usenix version").
* 150% faster than Ultrix 4.2A checksum routine.
*
* BSD changes: Jonathan Stone, Stanford Distributed Systems Group, 1997-08-11
*
* re-written for incremental checksumming of BSD mbufs
* and byteswap out-of-phase mbuf sums.
*/
#include <sys/param.h>
@ -54,8 +58,17 @@ union memptr {
static __inline u_int32_t fastsum __P((union memptr, int n, u_int sum, int odd));
/*
* Compute 1's complement sum over a contiguous block at 'buf' for 'n' bytes.
*
* Add the resulting checksum into 'oldsum' using 1's complement.
* 'odd_aligned' is a boolean which if set, indicate the data in 'buf'
* starts at an odd byte alignment within the containing packet,
* and so we must byteswap the memory-aligned 1's-complement sum
* over the data before adding it to `oldsum'.
*/
u_int32_t
fastsum(buf, n, oldsum, odd)
fastsum(buf, n, oldsum, odd_aligned)
union memptr buf;
int n;
unsigned int oldsum;
@ -64,11 +77,23 @@ fastsum(buf, n, oldsum, odd)
unsigned long w0, w1;
register unsigned int sum = 0;
/* Align to 32 bits. */
if (buf.u & 0x3) {
/* 16-bit-align. Have to do this first so short buffers done right. */
/*
* 16-bit-align.
* If buf is odd-byte-aligned, add the byte and toggle
* our byte-alignment flag.
* If we were odd-aligned on entry, an odd-aligned
* byte makes a 16-bit word with the previous odd byte,
* unaligned, making us aligned again.
* If we were not already odd-aligned, we are now,
* and we must byteswap our 16-bit-aligned sum of
*'buf' before accumulating it.
*/
if (buf.u & 0x1) {
sum += (*(buf.c++) << 8);
n -= 1;
odd_aligned = !odd_aligned;
}
/* 32-bit-align */
@ -182,14 +207,14 @@ fastsum(buf, n, oldsum, odd)
/*
* compensate for a trailing byte in previous mbuf
* by byteswapping the aligned sum of this mbuf.
* by byteswapping the memory-aligned sum of this mbuf.
*/
if (odd & 0x01) {
if (odd_aligned) {
sum = (sum & 0xffff) + (sum >> 16);
sum = (sum & 0xffff) + (sum >> 16);
sum = oldsum + ((sum >> 8) & 0xff) + ((sum & 0xff) << 8);
} else {
/* add upper and lower halfwords together to get full sum */
/* add upper and lower halfwords together to get full sum */
sum = oldsum + sum;
sum = (sum & 0xffff) + (sum >> 16);
}
@ -212,7 +237,7 @@ in_cksum(m, len)
register /*u_short **/ union memptr w;
register u_int32_t sum = 0;
register int mlen;
register int odd = 0;
register int odd_aligned = 0;
for ( ; m && len; m = m->m_next) {
@ -222,9 +247,9 @@ in_cksum(m, len)
if (mlen > len)
mlen = len;
w.c = mtod(m, u_char *);
sum = fastsum(w, mlen, sum, odd);
sum = fastsum(w, mlen, sum, odd_aligned);
len -= mlen;
odd += mlen;
odd_aligned = (odd_aligned + mlen) & 0x01;
}
if (len != 0) {
printf("in_cksum: out of data, %d\n", len);