226 lines
5.3 KiB
C
226 lines
5.3 KiB
C
/*
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* Licensed under the GPL
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*/
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#ifndef __UM_SYSDEP_CHECKSUM_H
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#define __UM_SYSDEP_CHECKSUM_H
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#include "linux/in6.h"
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#include "linux/string.h"
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/*
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* computes the checksum of a memory block at buff, length len,
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* and adds in "sum" (32-bit)
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*
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* returns a 32-bit number suitable for feeding into itself
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* or csum_tcpudp_magic
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*
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* this function must be called with even lengths, except
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* for the last fragment, which may be odd
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*
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* it's best to have buff aligned on a 32-bit boundary
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*/
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unsigned int csum_partial(const unsigned char * buff, int len,
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unsigned int sum);
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/*
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* Note: when you get a NULL pointer exception here this means someone
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* passed in an incorrect kernel address to one of these functions.
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*
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* If you use these functions directly please don't forget the
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* access_ok().
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*/
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static __inline__
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unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst,
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int len, int sum)
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{
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memcpy(dst, src, len);
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return csum_partial(dst, len, sum);
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}
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/*
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* the same as csum_partial, but copies from src while it
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* checksums, and handles user-space pointer exceptions correctly, when needed.
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*
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* here even more important to align src and dst on a 32-bit (or even
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* better 64-bit) boundary
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*/
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static __inline__
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unsigned int csum_partial_copy_from_user(const unsigned char __user *src,
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unsigned char *dst,
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int len, int sum, int *err_ptr)
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{
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if(copy_from_user(dst, src, len)){
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*err_ptr = -EFAULT;
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return(-1);
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}
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return csum_partial(dst, len, sum);
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}
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/*
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* These are the old (and unsafe) way of doing checksums, a warning message
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* will be printed if they are used and an exception occurs.
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*
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* these functions should go away after some time.
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*/
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#define csum_partial_copy_fromuser csum_partial_copy_from_user
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/*
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* This is a version of ip_compute_csum() optimized for IP headers,
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* which always checksum on 4 octet boundaries.
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*
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* By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
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* Arnt Gulbrandsen.
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*/
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static inline unsigned short ip_fast_csum(unsigned char * iph,
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unsigned int ihl)
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{
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unsigned int sum;
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__asm__ __volatile__(
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"movl (%1), %0 ;\n"
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"subl $4, %2 ;\n"
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"jbe 2f ;\n"
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"addl 4(%1), %0 ;\n"
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"adcl 8(%1), %0 ;\n"
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"adcl 12(%1), %0 ;\n"
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"1: adcl 16(%1), %0 ;\n"
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"lea 4(%1), %1 ;\n"
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"decl %2 ;\n"
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"jne 1b ;\n"
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"adcl $0, %0 ;\n"
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"movl %0, %2 ;\n"
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"shrl $16, %0 ;\n"
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"addw %w2, %w0 ;\n"
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"adcl $0, %0 ;\n"
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"notl %0 ;\n"
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"2: ;\n"
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/* Since the input registers which are loaded with iph and ipl
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are modified, we must also specify them as outputs, or gcc
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will assume they contain their original values. */
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: "=r" (sum), "=r" (iph), "=r" (ihl)
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: "1" (iph), "2" (ihl)
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: "memory");
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return sum;
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}
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/*
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* Fold a partial checksum
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*/
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static inline unsigned int csum_fold(unsigned int sum)
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{
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__asm__(
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"addl %1, %0 ;\n"
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"adcl $0xffff, %0 ;\n"
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: "=r" (sum)
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: "r" (sum << 16), "0" (sum & 0xffff0000)
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);
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return (~sum) >> 16;
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}
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static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
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unsigned long daddr,
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unsigned short len,
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unsigned short proto,
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unsigned int sum)
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{
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__asm__(
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"addl %1, %0 ;\n"
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"adcl %2, %0 ;\n"
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"adcl %3, %0 ;\n"
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"adcl $0, %0 ;\n"
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: "=r" (sum)
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: "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum));
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return sum;
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}
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/*
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* computes the checksum of the TCP/UDP pseudo-header
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* returns a 16-bit checksum, already complemented
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*/
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static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
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unsigned long daddr,
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unsigned short len,
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unsigned short proto,
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unsigned int sum)
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{
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return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
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}
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/*
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* this routine is used for miscellaneous IP-like checksums, mainly
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* in icmp.c
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*/
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static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
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{
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return csum_fold (csum_partial(buff, len, 0));
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}
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#define _HAVE_ARCH_IPV6_CSUM
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static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
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struct in6_addr *daddr,
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__u32 len,
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unsigned short proto,
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unsigned int sum)
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{
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__asm__(
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"addl 0(%1), %0 ;\n"
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"adcl 4(%1), %0 ;\n"
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"adcl 8(%1), %0 ;\n"
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"adcl 12(%1), %0 ;\n"
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"adcl 0(%2), %0 ;\n"
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"adcl 4(%2), %0 ;\n"
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"adcl 8(%2), %0 ;\n"
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"adcl 12(%2), %0 ;\n"
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"adcl %3, %0 ;\n"
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"adcl %4, %0 ;\n"
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"adcl $0, %0 ;\n"
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: "=&r" (sum)
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: "r" (saddr), "r" (daddr),
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"r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
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return csum_fold(sum);
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}
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/*
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* Copy and checksum to user
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*/
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#define HAVE_CSUM_COPY_USER
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static __inline__ unsigned int csum_and_copy_to_user(const unsigned char *src,
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unsigned char __user *dst,
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int len, int sum, int *err_ptr)
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{
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if (access_ok(VERIFY_WRITE, dst, len)){
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if(copy_to_user(dst, src, len)){
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*err_ptr = -EFAULT;
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return(-1);
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}
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return csum_partial(src, len, sum);
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}
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if (len)
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*err_ptr = -EFAULT;
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return -1; /* invalid checksum */
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}
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#endif
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/*
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* Overrides for Emacs so that we follow Linus's tabbing style.
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* Emacs will notice this stuff at the end of the file and automatically
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* adjust the settings for this buffer only. This must remain at the end
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* of the file.
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* ---------------------------------------------------------------------------
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* Local variables:
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* c-file-style: "linux"
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* End:
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*/
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