Use in_cksum_skip() to calculate in4_cksum instead of doing handrolled magic
(that does not compile with !gcc). Moreover we get the benefit for all archs that have a hand optimized in_cksum_skip(). Submitted by: yongari Tested by: me (i386, extensivly), pf4freebsd ML (various)
This commit is contained in:
mlaier
parent
bb9a9f2d55
commit
811c7ef3ca
@ -64,90 +64,37 @@
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*/
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#include <sys/param.h>
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#include <sys/mbuf.h>
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#include <sys/systm.h>
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#include <sys/socket.h>
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#include <net/route.h>
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#include <sys/mbuf.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#if defined(__FreeBSD__) && defined(__i386__)
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/*
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* Copied from FreeBSD 5.0 sys/i386/i386/in_cksum.c
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* XXX
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* Currently support I386 processor only.
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* In the long run, we need an optimized cksum routines for each Tier1
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* architecture. Due to the lack of available hardware except I386 I
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* can't support other processors now. For those users which use Sparc64,
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* Alpha processors can use more optimized version in FreeBSD.
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* See sys/$ARCH/$ARCH/in_cksum.c where $ARCH=`uname -p`
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*/
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/*
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* These asm statements require __volatile because they pass information
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* via the condition codes. GCC does not currently provide a way to specify
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* the condition codes as an input or output operand.
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*
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* The LOAD macro below is effectively a prefetch into cache. GCC will
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* load the value into a register but will not use it. Since modern CPUs
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* reorder operations, this will generally take place in parallel with
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* other calculations.
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*/
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#define ADD(n) __asm __volatile \
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("addl %1, %0" : "+r" (sum) : \
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"g" (((const u_int32_t *)w)[n / 4]))
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#define ADDC(n) __asm __volatile \
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("adcl %1, %0" : "+r" (sum) : \
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"g" (((const u_int32_t *)w)[n / 4]))
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#define LOAD(n) __asm __volatile \
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("" : : "r" (((const u_int32_t *)w)[n / 4]))
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#define MOP __asm __volatile \
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("adcl $0, %0" : "+r" (sum))
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#endif
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/*
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* Checksum routine for Internet Protocol family headers (Portable Version).
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* This is only for IPv4 pseudo header checksum.
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* No need to clear non-pseudo-header fields in IPv4 header.
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* len is for actual payload size, and does not include IPv4 header and
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* skipped header chain (off + len should be equal to the whole packet).
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*
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* This routine is very heavily used in the network
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* code and should be modified for each CPU to be as fast as possible.
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*/
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#include <machine/in_cksum.h>
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#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
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#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
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#if defined(__FreeBSD__)
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int
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in4_cksum(struct mbuf *m, u_int8_t nxt, int off, int len);
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#endif
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int in4_cksum(struct mbuf *, u_int8_t, int, int);
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int
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in4_cksum(m, nxt, off, len)
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struct mbuf *m;
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u_int8_t nxt;
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int off, len;
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in4_cksum(struct mbuf *m, u_int8_t nxt, int off, int len)
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{
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u_int16_t *w;
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int sum = 0;
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int mlen = 0;
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int byte_swapped = 0;
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union {
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struct ipovly ipov;
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u_int16_t w[10];
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} u;
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union {
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u_int8_t c[2];
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u_int16_t s;
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} s_util;
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union {
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u_int16_t s[2];
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u_int32_t l;
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} l_util;
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u_int16_t *w;
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int psum;
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int sum = 0;
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if (nxt != 0) {
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/* pseudo header */
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if (off < sizeof(struct ipovly))
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@ -165,223 +112,9 @@ in4_cksum(m, nxt, off, len)
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sum += w[5]; sum += w[6]; sum += w[7]; sum += w[8]; sum += w[9];
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}
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/* skip unnecessary part */
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while (m && off > 0) {
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if (m->m_len > off)
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break;
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off -= m->m_len;
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m = m->m_next;
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}
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for (;m && len; m = m->m_next) {
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if (m->m_len == 0)
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continue;
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w = (u_int16_t *)(mtod(m, caddr_t) + off);
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if (mlen == -1) {
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/*
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* The first byte of this mbuf is the continuation
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* of a word spanning between this mbuf and the
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* last mbuf.
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*
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* s_util.c[0] is already saved when scanning previous
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* mbuf.
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*/
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s_util.c[1] = *(u_int8_t *)w;
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sum += s_util.s;
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w = (u_int16_t *)((u_int8_t *)w + 1);
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mlen = m->m_len - off - 1;
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len--;
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} else
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mlen = m->m_len - off;
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off = 0;
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if (len < mlen)
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mlen = len;
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len -= mlen;
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#if defined(__FreeBSD__) && defined(__i386__)
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/*
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* Force to long boundary so we do longword aligned
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* memory operations
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*/
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if (3 & (int) w) {
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REDUCE;
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if ((1 & (int) w) && (mlen > 0)) {
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sum <<= 8;
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s_util.c[0] = *(char *)w;
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w = (u_short *)((char *)w + 1);
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mlen--;
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byte_swapped = 1;
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}
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if ((2 & (int) w) && (mlen >= 2)) {
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sum += *w++;
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mlen -= 2;
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}
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}
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/*
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* Advance to a 486 cache line boundary.
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*/
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if (4 & (int) w && mlen >= 4) {
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ADD(0);
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MOP;
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w += 2;
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mlen -= 4;
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}
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if (8 & (int) w && mlen >= 8) {
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ADD(0);
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ADDC(4);
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MOP;
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w += 4;
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mlen -= 8;
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}
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/*
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* Do as much of the checksum as possible 32 bits at at time.
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* In fact, this loop is unrolled to make overhead from
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* branches &c small.
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*/
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mlen -= 1;
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while ((mlen -= 32) >= 0) {
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/*
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* Add with carry 16 words and fold in the last
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* carry by adding a 0 with carry.
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*
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* The early ADD(16) and the LOAD(32) are to load
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* the next 2 cache lines in advance on 486's. The
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* 486 has a penalty of 2 clock cycles for loading
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* a cache line, plus whatever time the external
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* memory takes to load the first word(s) addressed.
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* These penalties are unavoidable. Subsequent
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* accesses to a cache line being loaded (and to
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* other external memory?) are delayed until the
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* whole load finishes. These penalties are mostly
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* avoided by not accessing external memory for
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* 8 cycles after the ADD(16) and 12 cycles after
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* the LOAD(32). The loop terminates when mlen
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* is initially 33 (not 32) to guaranteed that
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* the LOAD(32) is within bounds.
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*/
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ADD(16);
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ADDC(0);
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ADDC(4);
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ADDC(8);
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ADDC(12);
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LOAD(32);
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ADDC(20);
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ADDC(24);
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ADDC(28);
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MOP;
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w += 16;
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}
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mlen += 32 + 1;
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if (mlen >= 32) {
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ADD(16);
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ADDC(0);
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ADDC(4);
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ADDC(8);
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ADDC(12);
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ADDC(20);
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ADDC(24);
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ADDC(28);
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MOP;
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w += 16;
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mlen -= 32;
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}
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if (mlen >= 16) {
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ADD(0);
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ADDC(4);
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ADDC(8);
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ADDC(12);
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MOP;
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w += 8;
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mlen -= 16;
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}
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if (mlen >= 8) {
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ADD(0);
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ADDC(4);
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MOP;
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w += 4;
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mlen -= 8;
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}
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if (mlen == 0 && byte_swapped == 0)
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continue; /* worth 1% maybe ?? */
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REDUCE;
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while ((mlen -= 2) >= 0) {
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sum += *w++;
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}
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if (byte_swapped) {
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REDUCE;
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sum <<= 8;
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byte_swapped = 0;
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if (mlen == -1) {
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s_util.c[1] = *(char *)w;
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sum += s_util.s;
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mlen = 0;
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} else
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mlen = -1;
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} else if (mlen == -1)
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/*
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* This mbuf has odd number of bytes.
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* There could be a word split betwen
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* this mbuf and the next mbuf.
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* Save the last byte (to prepend to next mbuf).
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*/
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s_util.c[0] = *(char *)w;
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#else
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/*
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* Force to even boundary.
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*/
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if ((1 & (long) w) && (mlen > 0)) {
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REDUCE;
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sum <<= 8;
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s_util.c[0] = *(u_int8_t *)w;
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w = (u_int16_t *)((int8_t *)w + 1);
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mlen--;
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byte_swapped = 1;
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}
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/*
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* Unroll the loop to make overhead from
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* branches &c small.
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*/
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while ((mlen -= 32) >= 0) {
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sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
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sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
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sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
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sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
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w += 16;
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}
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mlen += 32;
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while ((mlen -= 8) >= 0) {
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sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
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w += 4;
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}
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mlen += 8;
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if (mlen == 0 && byte_swapped == 0)
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continue;
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REDUCE;
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while ((mlen -= 2) >= 0) {
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sum += *w++;
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}
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if (byte_swapped) {
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REDUCE;
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sum <<= 8;
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byte_swapped = 0;
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if (mlen == -1) {
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s_util.c[1] = *(u_int8_t *)w;
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sum += s_util.s;
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mlen = 0;
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} else
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mlen = -1;
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} else if (mlen == -1)
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s_util.c[0] = *(u_int8_t *)w;
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#endif
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}
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if (len)
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printf("cksum4: out of data\n");
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if (mlen == -1) {
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/* The last mbuf has odd # of bytes. Follow the
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standard (the odd byte may be shifted left by 8 bits
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or not as determined by endian-ness of the machine) */
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s_util.c[1] = 0;
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sum += s_util.s;
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}
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psum = in_cksum_skip(m, len + off, off);
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psum = ~psum & 0xffff;
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sum += psum;
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REDUCE;
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return (~sum & 0xffff);
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}
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