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Diffstat (limited to 'net/ipv4/checksum.c')
| -rw-r--r-- | net/ipv4/checksum.c | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/net/ipv4/checksum.c b/net/ipv4/checksum.c new file mode 100644 index 000000000..59355e967 --- /dev/null +++ b/net/ipv4/checksum.c @@ -0,0 +1,276 @@ +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * IP/TCP/UDP checksumming routines + * + * Authors: Jorge Cwik, <jorge@laser.satlink.net> + * Arnt Gulbrandsen, <agulbra@nvg.unit.no> + * Lots of code moved from tcp.c and ip.c; see those files + * for more names. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <net/checksum.h> +#ifdef __mips__ +#include <asm/string.h> +#endif + +/* + * computes a partial checksum, e.g. for TCP/UDP fragments + */ + +unsigned int csum_partial(unsigned char * buff, int len, unsigned int sum) { +#ifdef __i386__ + __asm__(" + movl %%ecx, %%edx + cld + shrl $5, %%ecx + jz 2f + orl %%ecx, %%ecx +1: movl (%%esi), %%eax + adcl %%eax, %%ebx + movl 4(%%esi), %%eax + adcl %%eax, %%ebx + movl 8(%%esi), %%eax + adcl %%eax, %%ebx + movl 12(%%esi), %%eax + adcl %%eax, %%ebx + movl 16(%%esi), %%eax + adcl %%eax, %%ebx + movl 20(%%esi), %%eax + adcl %%eax, %%ebx + movl 24(%%esi), %%eax + adcl %%eax, %%ebx + movl 28(%%esi), %%eax + adcl %%eax, %%ebx + lea 32(%%esi), %%esi + dec %%ecx + jne 1b + adcl $0, %%ebx +2: movl %%edx, %%ecx + andl $28, %%ecx + je 4f + shrl $2, %%ecx + orl %%ecx, %%ecx +3: adcl (%%esi), %%ebx + lea 4(%%esi), %%esi + dec %%ecx + jne 3b + adcl $0, %%ebx +4: movl $0, %%eax + testw $2, %%dx + je 5f + lodsw + addl %%eax, %%ebx + adcl $0, %%ebx + movw $0, %%ax +5: test $1, %%edx + je 6f + lodsb + addl %%eax, %%ebx + adcl $0, %%ebx +6: " + : "=b"(sum) + : "0"(sum), "c"(len), "S"(buff) + : "ax", "bx", "cx", "dx", "si" ); +#elif defined (__mips__) + unsigned long scratch1; + unsigned long scratch2; + + __asm__(" + .set noreorder + .set noat + move %1,%4 + srl %1,%1,5 + beqz %1,2f + sll %1,%1,5 # delay slot + + addu %1,%5 +1: lw %2,0(%5) + addu %5,32 + addu %0,%2 + sltu $1,%0,%2 + + lw %2,-28(%5) + addu %0,$1 + addu %0,%2 + sltu $1,%0,%2 + + lw %2,-24(%5) + addu %0,$1 + addu %0,%2 + sltu $1,%0,%2 + + lw %2,-20(%5) + addu %0,$1 + addu %0,%2 + sltu $1,%0,%2 + + lw %2,-16(%5) + addu %0,$1 + addu %0,%2 + sltu $1,%0,%2 + + lw %2,-12(%5) + addu %0,$1 + addu %0,%2 + sltu $1,%0,%2 + + lw %2,-8(%5) + addu %0,$1 + addu %0,%2 + sltu $1,%0,%2 + + lw %2,-4(%5) + addu %0,$1 + addu %0,%2 + sltu $1,%0,%2 + + bne %5,%1,1b + addu %0,$1 # delay slot + +2: srl %1,%4,2 + bnez %1,4f + addu %1,%5 # delay slot +3: lw %2,0(%5) + addu %5,4 + addu %0,%2 + sltu $1,%0,%2 + bne %5,%1,3b + addu %0,$1 # delay slot + +4: andi $1,%4,2 + beqz %4,5f + lhu %2,0(%5) # delay slot + addu %5,2 + addu %0,%2 + sltu $1,%0,%2 + addu %0,$1 # delay slot + +5: andi $1,%4,1 + beqz %4,6f + lbu %2,0(%5) # delay slot + addu %0,%2 + sltu $1,%0,%2 + addu %0,$1 # delay slot +6: .set at + .set reorder" + : "=r"(sum), "=r" (scratch1), "=r" (scratch2) + : "0"(sum), "r"(len), "r"(buff) + : "$1"); +#else +#error Not implemented for this CPU +#endif + return(sum); +} + + + +/* + * copy from fs while checksumming, otherwise like csum_partial + */ + +unsigned int csum_partial_copyffs( char *src, char *dst, + int len, int sum) { +#ifdef __i386__ + __asm__(" + push %%ds + push %%es + movw %%ds, %%dx + movw %%dx, %%es + movw %%fs, %%dx + movw %%dx, %%ds + cld + cmpl $32, %%ecx + jb 2f + pushl %%ecx + shrl $5, %%ecx + orl %%ecx, %%ecx +1: movl (%%esi), %%eax + movl 4(%%esi), %%edx + adcl %%eax, %%ebx + movl %%eax, %%es:(%%edi) + adcl %%edx, %%ebx + movl %%edx, %%es:4(%%edi) + + movl 8(%%esi), %%eax + movl 12(%%esi), %%edx + adcl %%eax, %%ebx + movl %%eax, %%es:8(%%edi) + adcl %%edx, %%ebx + movl %%edx, %%es:12(%%edi) + + movl 16(%%esi), %%eax + movl 20(%%esi), %%edx + adcl %%eax, %%ebx + movl %%eax, %%es:16(%%edi) + adcl %%edx, %%ebx + movl %%edx, %%es:20(%%edi) + + movl 24(%%esi), %%eax + movl 28(%%esi), %%edx + adcl %%eax, %%ebx + movl %%eax, %%es:24(%%edi) + adcl %%edx, %%ebx + movl %%edx, %%es:28(%%edi) + + lea 32(%%esi), %%esi + lea 32(%%edi), %%edi + dec %%ecx + jne 1b + adcl $0, %%ebx + popl %%ecx +2: movl %%ecx, %%edx + andl $28, %%ecx + je 4f + shrl $2, %%ecx + orl %%ecx, %%ecx +3: movl (%%esi), %%eax + adcl %%eax, %%ebx + movl %%eax, %%es:(%%edi) + lea 4(%%esi), %%esi + lea 4(%%edi), %%edi + dec %%ecx + jne 3b + adcl $0, %%ebx +4: movl $0, %%eax + testl $2, %%edx + je 5f + lodsw + stosw + addl %%eax, %%ebx + movw $0, %%ax + adcl %%eax, %%ebx +5: test $1, %%edx + je 6f + lodsb + stosb + addl %%eax, %%ebx + adcl $0, %%ebx +6: pop %%es + pop %%ds + " + : "=b"(sum) + : "0"(sum), "c"(len), "S"(src), "D"(dst) + : "ax", "bx", "cx", "dx", "si", "di" ); +#elif defined (__mips__) + /* + * It's 2:30 am and I don't feel like doing it real ... + * This is lots slower than the real thing (tm) + */ + sum = csum_partial(src, len, sum); + memcpy(dst, src, len); +#else +#error Not implemented for this CPU +#endif + return(sum); +} + + + |