diff options
Diffstat (limited to 'arch/parisc/lib/checksum.c')
| -rw-r--r-- | arch/parisc/lib/checksum.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/arch/parisc/lib/checksum.c b/arch/parisc/lib/checksum.c new file mode 100644 index 0000000..8a1e080 --- /dev/null +++ b/arch/parisc/lib/checksum.c @@ -0,0 +1,148 @@ +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * MIPS specific IP/TCP/UDP checksumming routines + * + * Authors: Ralf Baechle, <ralf@waldorf-gmbh.de> + * Lots of code moved from tcp.c and ip.c; see those files + * for more names. + * + * 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. + * + * $Id: checksum.c,v 1.3 1997/12/01 17:57:34 ralf Exp $ + */ +#include <linux/module.h> +#include <linux/types.h> + +#include <net/checksum.h> +#include <asm/byteorder.h> +#include <asm/string.h> +#include <asm/uaccess.h> + +#define addc(_t,_r) \ + __asm__ __volatile__ ( \ +" add %0, %1, %0\n" \ +" addc %0, %%r0, %0\n" \ + : "=r"(_t) \ + : "r"(_r), "0"(_t)); + +static inline unsigned short from32to16(unsigned int x) +{ + /* 32 bits --> 16 bits + carry */ + x = (x & 0xffff) + (x >> 16); + /* 16 bits + carry --> 16 bits including carry */ + x = (x & 0xffff) + (x >> 16); + return (unsigned short)x; +} + +static inline unsigned int do_csum(const unsigned char * buff, int len) +{ + int odd, count; + unsigned int result = 0; + + if (len <= 0) + goto out; + odd = 1 & (unsigned long) buff; + if (odd) { + result = be16_to_cpu(*buff); + len--; + buff++; + } + count = len >> 1; /* nr of 16-bit words.. */ + if (count) { + if (2 & (unsigned long) buff) { + result += *(unsigned short *) buff; + count--; + len -= 2; + buff += 2; + } + count >>= 1; /* nr of 32-bit words.. */ + if (count) { + while (count >= 4) { + unsigned int r1, r2, r3, r4; + r1 = *(unsigned int *)(buff + 0); + r2 = *(unsigned int *)(buff + 4); + r3 = *(unsigned int *)(buff + 8); + r4 = *(unsigned int *)(buff + 12); + addc(result, r1); + addc(result, r2); + addc(result, r3); + addc(result, r4); + count -= 4; + buff += 16; + } + while (count) { + unsigned int w = *(unsigned int *) buff; + count--; + buff += 4; + addc(result, w); + } + result = (result & 0xffff) + (result >> 16); + } + if (len & 2) { + result += *(unsigned short *) buff; + buff += 2; + } + } + if (len & 1) + result += le16_to_cpu(*buff); + result = from32to16(result); + if (odd) + result = swab16(result); +out: + return result; +} + +/* + * computes a partial checksum, e.g. for TCP/UDP fragments + */ +unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum) +{ + unsigned int result = do_csum(buff, len); + addc(result, sum); + return from32to16(result); +} + +EXPORT_SYMBOL(csum_partial); + +/* + * copy while checksumming, otherwise like csum_partial + */ +unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, + int len, unsigned int sum) +{ + /* + * It's 2:30 am and I don't feel like doing it real ... + * This is lots slower than the real thing (tm) + */ + sum = csum_partial(src, len, sum); + memcpy(dst, src, len); + + return sum; +} +EXPORT_SYMBOL(csum_partial_copy_nocheck); + +/* + * Copy from userspace and compute checksum. If we catch an exception + * then zero the rest of the buffer. + */ +unsigned int csum_partial_copy_from_user(const unsigned char __user *src, + unsigned char *dst, int len, + unsigned int sum, int *err_ptr) +{ + int missing; + + missing = copy_from_user(dst, src, len); + if (missing) { + memset(dst + len - missing, 0, missing); + *err_ptr = -EFAULT; + } + + return csum_partial(dst, len, sum); +} +EXPORT_SYMBOL(csum_partial_copy_from_user); |
