diff options
Diffstat (limited to 'arch/um/include/sysdep-x86_64/checksum.h')
| -rw-r--r-- | arch/um/include/sysdep-x86_64/checksum.h | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/arch/um/include/sysdep-x86_64/checksum.h b/arch/um/include/sysdep-x86_64/checksum.h new file mode 100644 index 00000000000..572c6c19be3 --- /dev/null +++ b/arch/um/include/sysdep-x86_64/checksum.h @@ -0,0 +1,151 @@ +/* + * Licensed under the GPL + */ + +#ifndef __UM_SYSDEP_CHECKSUM_H +#define __UM_SYSDEP_CHECKSUM_H + +#include "linux/string.h" +#include "linux/in6.h" +#include "asm/uaccess.h" + +extern unsigned int csum_partial_copy_from(const unsigned char *src, unsigned char *dst, int len, + int sum, int *err_ptr); +extern unsigned csum_partial(const unsigned char *buff, unsigned len, + unsigned sum); + +/* + * 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); +} + +/** + * csum_fold - Fold and invert a 32bit checksum. + * sum: 32bit unfolded sum + * + * Fold a 32bit running checksum to 16bit and invert it. This is usually + * the last step before putting a checksum into a packet. + * Make sure not to mix with 64bit checksums. + */ +static inline unsigned int csum_fold(unsigned int sum) +{ + __asm__( + " addl %1,%0\n" + " adcl $0xffff,%0" + : "=r" (sum) + : "r" (sum << 16), "0" (sum & 0xffff0000) + ); + return (~sum) >> 16; +} + +/** + * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum. + * @saddr: source address + * @daddr: destination address + * @len: length of packet + * @proto: ip protocol of packet + * @sum: initial sum to be added in (32bit unfolded) + * + * Returns the pseudo header checksum the input data. Result is + * 32bit unfolded. + */ +static inline unsigned long +csum_tcpudp_nofold(unsigned saddr, unsigned 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)); +} + +/** + * ip_fast_csum - Compute the IPv4 header checksum efficiently. + * iph: ipv4 header + * ihl: length of header / 4 + */ +static inline unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl) +{ + unsigned int sum; + + asm( " 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:" + /* 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); +} + +static inline unsigned add32_with_carry(unsigned a, unsigned b) +{ + asm("addl %2,%0\n\t" + "adcl $0,%0" + : "=r" (a) + : "0" (a), "r" (b)); + return a; +} + +#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: + */ |