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-rw-r--r--sys/netipx/ipx_cksum.c217
1 files changed, 60 insertions, 157 deletions
diff --git a/sys/netipx/ipx_cksum.c b/sys/netipx/ipx_cksum.c
index 4bb9124..02d8f93 100644
--- a/sys/netipx/ipx_cksum.c
+++ b/sys/netipx/ipx_cksum.c
@@ -38,173 +38,76 @@
#include <sys/param.h>
#include <sys/mbuf.h>
+#include <sys/libkern.h>
+#include <netipx/ipx.h>
#include <netipx/ipx_var.h>
-/*
- * Checksum routine for Network Systems Protocol Packets (Big-Endian).
- *
- * This routine is very heavily used in the network
- * code and should be modified for each CPU to be as fast as possible.
- */
-#define ADDCARRY(x) { if ((x) > 65535) (x) -= 65535; }
-#define FOLD(x) {l_util.l = (x); (x) = l_util.s[0] + l_util.s[1]; ADDCARRY(x);}
+#define SUMADV sum += *w++
u_short
-ipx_cksum(m, len)
- struct mbuf *m;
- int len;
-{
- register u_short *w;
- register int sum = 0;
- register int mlen = 0;
- register int sum2;
-
+ipx_cksum(struct mbuf *m, int len) {
+ u_int32_t sum = 0;
+ u_short *w;
+ u_char oldtc;
+ int mlen, words;
+ struct ipx *ipx;
union {
- u_short s[2];
- long l;
- } l_util;
+ u_char b[2];
+ u_short w;
+ } buf;
- for (;m != NULL && len; m = m->m_next) {
- if (m->m_len == 0)
- continue;
- /*
- * Each trip around loop adds in
- * word from one mbuf segment.
- */
- w = mtod(m, u_short *);
- if (mlen == -1) {
- /*
- * There is a byte left from the last segment;
- * ones-complement add it into the checksum.
- */
-#if BYTE_ORDER == BIG_ENDIAN
- sum += *(u_char *)w;
-#else
- sum += *(u_char *)w << 8;
-#endif
- sum += sum;
- w = (u_short *)(1 + (char *)w);
- mlen = m->m_len - 1;
- len--;
- FOLD(sum);
- } else
- mlen = m->m_len;
- if (len < mlen)
- mlen = len;
- len -= mlen;
- /*
- * We can do a 16 bit ones complement sum using
- * 32 bit arithmetic registers for adding,
- * with carries from the low added
- * into the high (by normal carry-chaining)
- * so long as we fold back before 16 carries have occured.
- */
- if (1 & (int) w)
- goto uuuuglyy;
-#ifndef TINY
-/* -DTINY reduces the size from 1250 to 550, but slows it down by 22% */
- while ((mlen -= 32) >= 0) {
- sum += w[0]; sum += sum; sum += w[1]; sum += sum;
- sum += w[2]; sum += sum; sum += w[3]; sum += sum;
- sum += w[4]; sum += sum; sum += w[5]; sum += sum;
- sum += w[6]; sum += sum; sum += w[7]; sum += sum;
- FOLD(sum);
- sum += w[8]; sum += sum; sum += w[9]; sum += sum;
- sum += w[10]; sum += sum; sum += w[11]; sum += sum;
- sum += w[12]; sum += sum; sum += w[13]; sum += sum;
- sum += w[14]; sum += sum; sum += w[15]; sum += sum;
- FOLD(sum);
- w += 16;
- }
- mlen += 32;
-#endif
- while ((mlen -= 8) >= 0) {
- sum += w[0]; sum += sum; sum += w[1]; sum += sum;
- sum += w[2]; sum += sum; sum += w[3]; sum += sum;
- FOLD(sum);
- w += 4;
- }
- mlen += 8;
- while ((mlen -= 2) >= 0) {
- sum += *w++; sum += sum;
- }
- goto commoncase;
-uuuuglyy:
-#if BYTE_ORDER == BIG_ENDIAN
-#define ww(n) (((u_char *)w)[n + n + 1])
-#define vv(n) (((u_char *)w)[n + n])
-#else
-#if BYTE_ORDER == LITTLE_ENDIAN
-#define vv(n) (((u_char *)w)[n + n + 1])
-#define ww(n) (((u_char *)w)[n + n])
-#endif
-#endif
- sum2 = 0;
-#ifndef TINY
- while ((mlen -= 32) >= 0) {
- sum += ww(0); sum += sum; sum += ww(1); sum += sum;
- sum += ww(2); sum += sum; sum += ww(3); sum += sum;
- sum += ww(4); sum += sum; sum += ww(5); sum += sum;
- sum += ww(6); sum += sum; sum += ww(7); sum += sum;
- FOLD(sum);
- sum += ww(8); sum += sum; sum += ww(9); sum += sum;
- sum += ww(10); sum += sum; sum += ww(11); sum += sum;
- sum += ww(12); sum += sum; sum += ww(13); sum += sum;
- sum += ww(14); sum += sum; sum += ww(15); sum += sum;
- FOLD(sum);
- sum2 += vv(0); sum2 += sum2; sum2 += vv(1); sum2 += sum2;
- sum2 += vv(2); sum2 += sum2; sum2 += vv(3); sum2 += sum2;
- sum2 += vv(4); sum2 += sum2; sum2 += vv(5); sum2 += sum2;
- sum2 += vv(6); sum2 += sum2; sum2 += vv(7); sum2 += sum2;
- FOLD(sum2);
- sum2 += vv(8); sum2 += sum2; sum2 += vv(9); sum2 += sum2;
- sum2 += vv(10); sum2 += sum2; sum2 += vv(11); sum2 += sum2;
- sum2 += vv(12); sum2 += sum2; sum2 += vv(13); sum2 += sum2;
- sum2 += vv(14); sum2 += sum2; sum2 += vv(15); sum2 += sum2;
- FOLD(sum2);
- w += 16;
- }
- mlen += 32;
-#endif
- while ((mlen -= 8) >= 0) {
- sum += ww(0); sum += sum; sum += ww(1); sum += sum;
- sum += ww(2); sum += sum; sum += ww(3); sum += sum;
- FOLD(sum);
- sum2 += vv(0); sum2 += sum2; sum2 += vv(1); sum2 += sum2;
- sum2 += vv(2); sum2 += sum2; sum2 += vv(3); sum2 += sum2;
- FOLD(sum2);
- w += 4;
- }
- mlen += 8;
- while ((mlen -= 2) >= 0) {
- sum += ww(0); sum += sum;
- sum2 += vv(0); sum2 += sum2;
- w++;
+ ipx = mtod(m, struct ipx*);
+ oldtc = ipx->ipx_tc;
+ ipx->ipx_tc = 0;
+ w = &ipx->ipx_len;
+ len -= 2;
+ mlen = 2;
+
+ for(;;) {
+ mlen = imin(m->m_len - mlen, len);
+ words = mlen / 2;
+ len -= mlen & ~1;
+ while (words >= 16) {
+ SUMADV; SUMADV; SUMADV; SUMADV;
+ SUMADV; SUMADV; SUMADV; SUMADV;
+ SUMADV; SUMADV; SUMADV; SUMADV;
+ SUMADV; SUMADV; SUMADV; SUMADV;
+ words -= 16;
}
- sum += (sum2 << 8);
-commoncase:
- if (mlen == -1) {
-#if BYTE_ORDER == BIG_ENDIAN
- sum += *(u_char *)w << 8;
-#else
- sum += *(u_char *)w;
-#endif
+ while (words--)
+ SUMADV;
+ if (len == 0)
+ break;
+ mlen &= 1;
+ if (mlen) {
+ buf.b[0] = *(u_char*)w;
+ if (--len == 0) {
+ buf.b[1] = 0;
+ sum += buf.w;
+ break;
+ }
}
- FOLD(sum);
+ m = m->m_next;
+ if (m == NULL)
+ break;
+ w = mtod(m, u_short*);
+ if (mlen) {
+ buf.b[1] = *(u_char*)w;
+ sum += buf.w;
+ ((u_char*)w)++;
+ if (--len == 0)
+ break;
+ }
}
- if (mlen == -1) {
- /* We had an odd number of bytes to sum; assume a garbage
- byte of zero and clean up */
- sum += sum;
- FOLD(sum);
- }
- /*
- * sum has already been kept to low sixteen bits.
- * just examine result and exit.
- */
- if(sum == 0xffff)
- sum = 0;
+
+ ipx->ipx_tc = oldtc;
+
+ sum = (sum & 0xffff) + (sum >> 16);
+ if (sum >= 0x10000)
+ sum++;
+ if (sum)
+ sum = ~sum;
return (sum);
}
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