| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifdef __KERNEL__ |
| 2 | #ifndef _PPC_CHECKSUM_H |
| 3 | #define _PPC_CHECKSUM_H |
| 4 | |
| 5 | |
| 6 | /* |
| 7 | * computes the checksum of a memory block at buff, length len, |
| 8 | * and adds in "sum" (32-bit) |
| 9 | * |
| 10 | * returns a 32-bit number suitable for feeding into itself |
| 11 | * or csum_tcpudp_magic |
| 12 | * |
| 13 | * this function must be called with even lengths, except |
| 14 | * for the last fragment, which may be odd |
| 15 | * |
| 16 | * it's best to have buff aligned on a 32-bit boundary |
| 17 | */ |
| 18 | extern unsigned int csum_partial(const unsigned char * buff, int len, |
| 19 | unsigned int sum); |
| 20 | |
| 21 | /* |
| 22 | * Computes the checksum of a memory block at src, length len, |
| 23 | * and adds in "sum" (32-bit), while copying the block to dst. |
| 24 | * If an access exception occurs on src or dst, it stores -EFAULT |
| 25 | * to *src_err or *dst_err respectively (if that pointer is not |
| 26 | * NULL), and, for an error on src, zeroes the rest of dst. |
| 27 | * |
| 28 | * Like csum_partial, this must be called with even lengths, |
| 29 | * except for the last fragment. |
| 30 | */ |
| 31 | extern unsigned int csum_partial_copy_generic(const char *src, char *dst, |
| 32 | int len, unsigned int sum, |
| 33 | int *src_err, int *dst_err); |
| 34 | |
| 35 | #define csum_partial_copy_from_user(src, dst, len, sum, errp) \ |
| 36 | csum_partial_copy_generic((__force void *)(src), (dst), (len), (sum), (errp), NULL) |
| 37 | |
| 38 | /* FIXME: this needs to be written to really do no check -- Cort */ |
| 39 | #define csum_partial_copy_nocheck(src, dst, len, sum) \ |
| 40 | csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL) |
| 41 | |
| 42 | /* |
| 43 | * turns a 32-bit partial checksum (e.g. from csum_partial) into a |
| 44 | * 1's complement 16-bit checksum. |
| 45 | */ |
| 46 | static inline unsigned int csum_fold(unsigned int sum) |
| 47 | { |
| 48 | unsigned int tmp; |
| 49 | |
| 50 | /* swap the two 16-bit halves of sum */ |
| 51 | __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum)); |
| 52 | /* if there is a carry from adding the two 16-bit halves, |
| 53 | it will carry from the lower half into the upper half, |
| 54 | giving us the correct sum in the upper half. */ |
| 55 | sum = ~(sum + tmp) >> 16; |
| 56 | return sum; |
| 57 | } |
| 58 | |
| 59 | /* |
| 60 | * this routine is used for miscellaneous IP-like checksums, mainly |
| 61 | * in icmp.c |
| 62 | */ |
| 63 | static inline unsigned short ip_compute_csum(unsigned char * buff, int len) |
| 64 | { |
| 65 | return csum_fold(csum_partial(buff, len, 0)); |
| 66 | } |
| 67 | |
| 68 | /* |
| 69 | * FIXME: I swiped this one from the sparc and made minor modifications. |
| 70 | * It may not be correct. -- Cort |
| 71 | */ |
| 72 | static inline unsigned long csum_tcpudp_nofold(unsigned long saddr, |
| 73 | unsigned long daddr, |
| 74 | unsigned short len, |
| 75 | unsigned short proto, |
| 76 | unsigned int sum) |
| 77 | { |
| 78 | __asm__("\n\ |
| 79 | addc %0,%0,%1 \n\ |
| 80 | adde %0,%0,%2 \n\ |
| 81 | adde %0,%0,%3 \n\ |
| 82 | addze %0,%0 \n\ |
| 83 | " |
| 84 | : "=r" (sum) |
| 85 | : "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum)); |
| 86 | return sum; |
| 87 | } |
| 88 | |
| 89 | /* |
| 90 | * This is a version of ip_compute_csum() optimized for IP headers, |
| 91 | * which always checksum on 4 octet boundaries. ihl is the number |
| 92 | * of 32-bit words and is always >= 5. |
| 93 | */ |
| 94 | extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl); |
| 95 | |
| 96 | /* |
| 97 | * computes the checksum of the TCP/UDP pseudo-header |
| 98 | * returns a 16-bit checksum, already complemented |
| 99 | */ |
| 100 | extern unsigned short csum_tcpudp_magic(unsigned long saddr, |
| 101 | unsigned long daddr, |
| 102 | unsigned short len, |
| 103 | unsigned short proto, |
| 104 | unsigned int sum); |
| 105 | |
| 106 | #endif |
| 107 | #endif /* __KERNEL__ */ |