linux-mm / page-reclaim / cd52d1ee9a92587b242d946a2300a3245d3b885a / . / include / asm-powerpc / checksum.h

#ifndef _ASM_POWERPC_CHECKSUM_H | |

#define _ASM_POWERPC_CHECKSUM_H | |

/* | |

* 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. | |

*/ | |

/* | |

* This is a version of ip_compute_csum() optimized for IP headers, | |

* which always checksum on 4 octet boundaries. ihl is the number | |

* of 32-bit words and is always >= 5. | |

*/ | |

extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl); | |

/* | |

* computes the checksum of the TCP/UDP pseudo-header | |

* returns a 16-bit checksum, already complemented | |

*/ | |

extern unsigned short csum_tcpudp_magic(unsigned long saddr, | |

unsigned long daddr, | |

unsigned short len, | |

unsigned short proto, | |

unsigned int 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 | |

*/ | |

extern unsigned int csum_partial(const unsigned char * buff, int len, | |

unsigned int sum); | |

/* | |

* Computes the checksum of a memory block at src, length len, | |

* and adds in "sum" (32-bit), while copying the block to dst. | |

* If an access exception occurs on src or dst, it stores -EFAULT | |

* to *src_err or *dst_err respectively (if that pointer is not | |

* NULL), and, for an error on src, zeroes the rest of dst. | |

* | |

* Like csum_partial, this must be called with even lengths, | |

* except for the last fragment. | |

*/ | |

extern unsigned int csum_partial_copy_generic(const char *src, char *dst, | |

int len, unsigned int sum, | |

int *src_err, int *dst_err); | |

/* | |

* the same as csum_partial, but copies from src to dst while it | |

* checksums. | |

*/ | |

unsigned int csum_partial_copy_nocheck(const char *src, | |

char *dst, | |

int len, | |

unsigned int sum); | |

#define csum_partial_copy_from_user(src, dst, len, sum, errp) \ | |

csum_partial_copy_generic((src), (dst), (len), (sum), (errp), NULL) | |

#define csum_partial_copy_nocheck(src, dst, len, sum) \ | |

csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL) | |

/* | |

* turns a 32-bit partial checksum (e.g. from csum_partial) into a | |

* 1's complement 16-bit checksum. | |

*/ | |

static inline unsigned int csum_fold(unsigned int sum) | |

{ | |

unsigned int tmp; | |

/* swap the two 16-bit halves of sum */ | |

__asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum)); | |

/* if there is a carry from adding the two 16-bit halves, | |

it will carry from the lower half into the upper half, | |

giving us the correct sum in the upper half. */ | |

sum = ~(sum + tmp) >> 16; | |

return 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)); | |

} | |

#ifdef __powerpc64__ | |

static inline u32 csum_tcpudp_nofold(u32 saddr, | |

u32 daddr, | |

unsigned short len, | |

unsigned short proto, | |

unsigned int sum) | |

{ | |

unsigned long s = sum; | |

s += saddr; | |

s += daddr; | |

s += (proto << 16) + len; | |

s += (s >> 32); | |

return (u32) s; | |

} | |

#else | |

static inline unsigned long csum_tcpudp_nofold(unsigned long saddr, | |

unsigned long daddr, | |

unsigned short len, | |

unsigned short proto, | |

unsigned int sum) | |

{ | |

__asm__("\n\ | |

addc %0,%0,%1 \n\ | |

adde %0,%0,%2 \n\ | |

adde %0,%0,%3 \n\ | |

addze %0,%0 \n\ | |

" | |

: "=r" (sum) | |

: "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum)); | |

return sum; | |

} | |

#endif | |

#endif |