diff options
Diffstat (limited to 'sys/netipx/ipx_cksum.c')
-rw-r--r-- | sys/netipx/ipx_cksum.c | 217 |
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); } |