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Diffstat (limited to 'arch/um/include/sysdep-i386/checksum.h')
| -rw-r--r-- | arch/um/include/sysdep-i386/checksum.h | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/arch/um/include/sysdep-i386/checksum.h b/arch/um/include/sysdep-i386/checksum.h new file mode 100644 index 00000000000..3a2a45811aa --- /dev/null +++ b/arch/um/include/sysdep-i386/checksum.h @@ -0,0 +1,219 @@ +/* + * Licensed under the GPL + */ + +#ifndef __UM_SYSDEP_CHECKSUM_H +#define __UM_SYSDEP_CHECKSUM_H + +#include "linux/in6.h" +#include "linux/string.h" + +/* + * 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(const unsigned char * buff, int len, + unsigned int sum); + +/* + * the same as csum_partial, but copies from src while it + * checksums, and handles user-space pointer exceptions correctly, when needed. + * + * here even more important to align src and dst on a 32-bit (or even + * better 64-bit) boundary + */ + +unsigned int csum_partial_copy_to(const unsigned char *src, unsigned char *dst, + int len, int sum, int *err_ptr); +unsigned int csum_partial_copy_from(const unsigned char *src, unsigned char *dst, + int len, int sum, int *err_ptr); + +/* + * Note: when you get a NULL pointer exception here this means someone + * passed in an incorrect kernel address to one of these functions. + * + * If you use these functions directly please don't forget the + * access_ok(). + */ + +static __inline__ +unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, + int len, int sum) +{ + memcpy(dst, src, len); + return(csum_partial(dst, len, sum)); +} + +static __inline__ +unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst, + int len, int sum, int *err_ptr) +{ + return csum_partial_copy_from(src, dst, len, sum, err_ptr); +} + +/* + * These are the old (and unsafe) way of doing checksums, a warning message + * will be printed if they are used and an exception occurs. + * + * these functions should go away after some time. + */ + +#define csum_partial_copy_fromuser csum_partial_copy_from_user +unsigned int csum_partial_copy(const unsigned char *src, unsigned char *dst, int len, int sum); + +/* + * 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 int sum; + + __asm__ __volatile__( + "movl (%1), %0 ;\n" + "subl $4, %2 ;\n" + "jbe 2f ;\n" + "addl 4(%1), %0 ;\n" + "adcl 8(%1), %0 ;\n" + "adcl 12(%1), %0 ;\n" +"1: adcl 16(%1), %0 ;\n" + "lea 4(%1), %1 ;\n" + "decl %2 ;\n" + "jne 1b ;\n" + "adcl $0, %0 ;\n" + "movl %0, %2 ;\n" + "shrl $16, %0 ;\n" + "addw %w2, %w0 ;\n" + "adcl $0, %0 ;\n" + "notl %0 ;\n" +"2: ;\n" + /* Since the input registers which are loaded with iph and ipl + are modified, we must also specify them as outputs, or gcc + will assume they contain their original values. */ + : "=r" (sum), "=r" (iph), "=r" (ihl) + : "1" (iph), "2" (ihl) + : "memory"); + return(sum); +} + +/* + * Fold a partial checksum + */ + +static inline unsigned int csum_fold(unsigned int sum) +{ + __asm__( + "addl %1, %0 ;\n" + "adcl $0xffff, %0 ;\n" + : "=r" (sum) + : "r" (sum << 16), "0" (sum & 0xffff0000) + ); + return (~sum) >> 16; +} + +static inline unsigned long csum_tcpudp_nofold(unsigned long saddr, + unsigned long daddr, + unsigned short len, + unsigned short proto, + unsigned int sum) +{ + __asm__( + "addl %1, %0 ;\n" + "adcl %2, %0 ;\n" + "adcl %3, %0 ;\n" + "adcl $0, %0 ;\n" + : "=r" (sum) + : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum)); + 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) +{ + return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,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) +{ + return csum_fold (csum_partial(buff, len, 0)); +} + +#define _HAVE_ARCH_IPV6_CSUM +static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr, + struct in6_addr *daddr, + __u32 len, + unsigned short proto, + unsigned int sum) +{ + __asm__( + "addl 0(%1), %0 ;\n" + "adcl 4(%1), %0 ;\n" + "adcl 8(%1), %0 ;\n" + "adcl 12(%1), %0 ;\n" + "adcl 0(%2), %0 ;\n" + "adcl 4(%2), %0 ;\n" + "adcl 8(%2), %0 ;\n" + "adcl 12(%2), %0 ;\n" + "adcl %3, %0 ;\n" + "adcl %4, %0 ;\n" + "adcl $0, %0 ;\n" + : "=&r" (sum) + : "r" (saddr), "r" (daddr), + "r"(htonl(len)), "r"(htonl(proto)), "0"(sum)); + + return csum_fold(sum); +} + +/* + * Copy and checksum to user + */ +#define HAVE_CSUM_COPY_USER +static __inline__ unsigned int csum_and_copy_to_user(const unsigned char *src, + unsigned char *dst, + int len, int sum, int *err_ptr) +{ + if (access_ok(VERIFY_WRITE, dst, len)) + return(csum_partial_copy_to(src, dst, len, sum, err_ptr)); + + if (len) + *err_ptr = -EFAULT; + + return -1; /* invalid checksum */ +} + +#endif + +/* + * Overrides for Emacs so that we follow Linus's tabbing style. + * Emacs will notice this stuff at the end of the file and automatically + * adjust the settings for this buffer only. This must remain at the end + * of the file. + * --------------------------------------------------------------------------- + * Local variables: + * c-file-style: "linux" + * End: + */ |