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Diffstat (limited to 'include/net/checksum.h')
| -rw-r--r-- | include/net/checksum.h | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/include/net/checksum.h b/include/net/checksum.h new file mode 100644 index 000000000..7f9492328 --- /dev/null +++ b/include/net/checksum.h @@ -0,0 +1,237 @@ +/* + * 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. + * + * Checksumming functions for IP, TCP, UDP and so on + * + * Authors: Jorge Cwik, <jorge@laser.satlink.net> + * Arnt Gulbrandsen, <agulbra@nvg.unit.no> + * Borrows very liberally 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. + */ +#ifndef _CHECKSUM_H +#define _CHECKSUM_H + +#include <asm/byteorder.h> +#include "ip.h" + +/* + * This is a version of ip_compute_csum() optimized for IP headers, + * which always checksum on 4 octet boundaries. + * + * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by + * Arnt Gulbrandsen. + */ +static inline unsigned short ip_fast_csum(unsigned char * iph, + unsigned int ihl) { + unsigned short int sum; + +#ifdef __i386__ + __asm__(" + movl (%%esi), %%eax + andl $15, %%ecx + subl $4, %%ecx + jbe 2f + addl 4(%%esi), %%eax + adcl 8(%%esi), %%eax + adcl 12(%%esi), %%eax +1: adcl 16(%%esi), %%eax + lea 4(%%esi), %%esi + decl %%ecx + jne 1b + adcl $0, %%eax + movl %%eax, %%ecx + shrl $16, %%eax + addw %%ecx, %%eax + adcl $0, %%eax + notl %%eax + andl $65535, %%eax +2: + " + : "=a" (sum) + : "S" (iph), "c"(ihl) + : "ax", "cx", "si"); +#elif defined (__mips__) + unsigned long dummy1, dummy2; + /* + * This is optimized for 32-bit MIPS processors. + * I tried it in plain C but the generated code looks to bad to + * use with old first generation MIPS CPUs. + * Using 64-bit code could even further improve these routines. + */ + __asm__(" + .set noreorder + .set noat + lw %0,(%3) + subu %1,4 + blez %1,2f + sll %1,%4,2 # delay slot + lw %2,4(%3) + addu %1,%3 # delay slot + addu %0,%2 + sltu $1,%0,%2 + lw %2,8(%3) + addu %0,$1 + addu %0,%2 + sltu $1,%0,%2 + lw %2,12(%3) + addu %0,$1 + addu %0,%2 + sltu $1,%0,%2 + addu %0,$1 +1: lw %2,16(%3) + addu %1,4 + addu %0,%2 + sltu $1,%0,%2 + bne %1,%3,1b + addu %0,$1 # delay slot + srl $1,%0,16 + addu %0,$1 + sltu $1,%0,$1 + addu %0,$1 + nor %0,$0,%0 + andi %0,0xffff +2: .set at + .set reorder" + : "=r" (sum), "=r" (dummy1), "=r" (dummy2) + : "r" (iph), "r"(ihl) + : "$1"); +#else +#error Not implemented for this CPU +#endif + return(sum); +} + + + + +/* + * computes the checksum of the TCP/UDP pseudo-header + * returns a 16-bit checksum, already complemented + */ + +static inline unsigned short int csum_tcpudp_magic(unsigned long saddr, + unsigned long daddr, + unsigned short len, + unsigned short proto, + unsigned int sum) { +#ifdef __i386__ + __asm__(" + addl %2, %0 + adcl %3, %0 + adcl %4, %0 + adcl $0, %0 + movl %0, %2 + shrl $16, %2 + addw %2, %0 + adcl $0, %0 + notl %0 + andl $65535, %0 + " + : "=r" (sum) + : "0" (daddr), "S"(saddr), "r"((ntohs(len)<<16)+proto*256), "r"(sum) + : "si" ); +#elif defined (__mips__) + __asm__(" + .set noat + addu %0,%2 + sltu $1,%0,%2 + addu %0,$1 + addu %0,%3 + sltu $1,%0,%3 + addu %0,$1 + addu %0,%4 + sltu $1,%0,%4 + addu %0,$1 + srl $1,%0,16 + addu %0,$1 + sltu $1,%0,$1 + addu %0,$1 + nor %0,$0,%0 + andi %0,0xffff + .set at" + : "=r" (sum) + : "0" (daddr), "r"(saddr), "r"((ntohs(len)<<16)+proto*256), "r"(sum) + : "$1"); +#else +#error Not implemented for this CPU +#endif + return((unsigned short)sum); +} + + + +/* + * computes the checksum of a memory block at buff, length len, + * and adds in "sum" (32-bit) + * + * returns a 32-bit number suitable for feeding into itself + * or csum_tcpudp_magic + * + * this function must be called with even lengths, except + * for the last fragment, which may be odd + * + * it's best to have buff aligned on a 32-bit boundary + */ +unsigned int csum_partial(unsigned char * buff, int len, unsigned int sum); + + + +/* + * the same as csum_partial, but copies from fs:src while it + * checksums + * + * here even more important to align src and dst on a 32-bit (or even + * better 64-bit) boundary + */ + +unsigned int csum_partial_copyffs( char *src, char *dst, int len, int sum); + + + + +/* + * this routine is used for miscellaneous IP-like checksums, mainly + * in icmp.c + */ + +static inline unsigned short ip_compute_csum(unsigned char * buff, int len) { + unsigned short int sum; + +#ifdef __i386__ + __asm__(" + movl %%eax, %%ecx + shrl $16, %%ecx + addw %%cx, %%ax + adcl $0, %%eax + notl %%eax + andl $65535, %%eax + " + : "=a"(sum) + : "a" (csum_partial(buff, len, 0)) + : "cx"); +#elif defined (__mips__) + __asm__(" + .set noat + srl $1,%0,16 + addu %0,$1 + sltu $1,%0,$1 + nor %0,$0,%0 + andi %0,0xffff + .set at" + : "=r"(sum) + : "r" (csum_partial(buff, len, 0)) + : "$1"); +#else +#error Not implemented for this CPU +#endif + return(sum); +} + +#endif |