11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * arch/alpha/lib/checksum.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * This file contains network checksum routines that are better done 51da177e4SLinus Torvalds * in an architecture-specific manner due to speed.. 61da177e4SLinus Torvalds * Comments in other versions indicate that the algorithms are from RFC1071 71da177e4SLinus Torvalds * 8c3a2ddeeSSimon Arlott * accelerated versions (and 21264 assembly versions ) contributed by 91da177e4SLinus Torvalds * Rick Gorton <rick.gorton@alpha-processor.com> 101da177e4SLinus Torvalds */ 111da177e4SLinus Torvalds 121da177e4SLinus Torvalds #include <linux/module.h> 131da177e4SLinus Torvalds #include <linux/string.h> 141da177e4SLinus Torvalds 151da177e4SLinus Torvalds #include <asm/byteorder.h> 161da177e4SLinus Torvalds 171da177e4SLinus Torvalds static inline unsigned short from64to16(unsigned long x) 181da177e4SLinus Torvalds { 191da177e4SLinus Torvalds /* Using extract instructions is a bit more efficient 201da177e4SLinus Torvalds than the original shift/bitmask version. */ 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds union { 231da177e4SLinus Torvalds unsigned long ul; 241da177e4SLinus Torvalds unsigned int ui[2]; 251da177e4SLinus Torvalds unsigned short us[4]; 261da177e4SLinus Torvalds } in_v, tmp_v, out_v; 271da177e4SLinus Torvalds 281da177e4SLinus Torvalds in_v.ul = x; 291da177e4SLinus Torvalds tmp_v.ul = (unsigned long) in_v.ui[0] + (unsigned long) in_v.ui[1]; 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds /* Since the bits of tmp_v.sh[3] are going to always be zero, 321da177e4SLinus Torvalds we don't have to bother to add that in. */ 331da177e4SLinus Torvalds out_v.ul = (unsigned long) tmp_v.us[0] + (unsigned long) tmp_v.us[1] 341da177e4SLinus Torvalds + (unsigned long) tmp_v.us[2]; 351da177e4SLinus Torvalds 361da177e4SLinus Torvalds /* Similarly, out_v.us[2] is always zero for the final add. */ 371da177e4SLinus Torvalds return out_v.us[0] + out_v.us[1]; 381da177e4SLinus Torvalds } 391da177e4SLinus Torvalds 401da177e4SLinus Torvalds /* 411da177e4SLinus Torvalds * computes the checksum of the TCP/UDP pseudo-header 421da177e4SLinus Torvalds * returns a 16-bit checksum, already complemented. 431da177e4SLinus Torvalds */ 449be259aaSAl Viro __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 4501cfbad7SAlexander Duyck __u32 len, __u8 proto, __wsum sum) 461da177e4SLinus Torvalds { 479be259aaSAl Viro return (__force __sum16)~from64to16( 489be259aaSAl Viro (__force u64)saddr + (__force u64)daddr + 499be259aaSAl Viro (__force u64)sum + ((len + proto) << 8)); 501da177e4SLinus Torvalds } 5100fc0e0dSAl Viro EXPORT_SYMBOL(csum_tcpudp_magic); 521da177e4SLinus Torvalds 539be259aaSAl Viro __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 5401cfbad7SAlexander Duyck __u32 len, __u8 proto, __wsum sum) 551da177e4SLinus Torvalds { 561da177e4SLinus Torvalds unsigned long result; 571da177e4SLinus Torvalds 589be259aaSAl Viro result = (__force u64)saddr + (__force u64)daddr + 599be259aaSAl Viro (__force u64)sum + ((len + proto) << 8); 601da177e4SLinus Torvalds 611da177e4SLinus Torvalds /* Fold down to 32-bits so we don't lose in the typedef-less 621da177e4SLinus Torvalds network stack. */ 631da177e4SLinus Torvalds /* 64 to 33 */ 641da177e4SLinus Torvalds result = (result & 0xffffffff) + (result >> 32); 651da177e4SLinus Torvalds /* 33 to 32 */ 661da177e4SLinus Torvalds result = (result & 0xffffffff) + (result >> 32); 679be259aaSAl Viro return (__force __wsum)result; 681da177e4SLinus Torvalds } 69547c178bSAl Viro EXPORT_SYMBOL(csum_tcpudp_nofold); 701da177e4SLinus Torvalds 711da177e4SLinus Torvalds /* 721da177e4SLinus Torvalds * Do a 64-bit checksum on an arbitrary memory area.. 731da177e4SLinus Torvalds * 741da177e4SLinus Torvalds * This isn't a great routine, but it's not _horrible_ either. The 751da177e4SLinus Torvalds * inner loop could be unrolled a bit further, and there are better 761da177e4SLinus Torvalds * ways to do the carry, but this is reasonable. 771da177e4SLinus Torvalds */ 781da177e4SLinus Torvalds static inline unsigned long do_csum(const unsigned char * buff, int len) 791da177e4SLinus Torvalds { 801da177e4SLinus Torvalds int odd, count; 811da177e4SLinus Torvalds unsigned long result = 0; 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds if (len <= 0) 841da177e4SLinus Torvalds goto out; 851da177e4SLinus Torvalds odd = 1 & (unsigned long) buff; 861da177e4SLinus Torvalds if (odd) { 871da177e4SLinus Torvalds result = *buff << 8; 881da177e4SLinus Torvalds len--; 891da177e4SLinus Torvalds buff++; 901da177e4SLinus Torvalds } 911da177e4SLinus Torvalds count = len >> 1; /* nr of 16-bit words.. */ 921da177e4SLinus Torvalds if (count) { 931da177e4SLinus Torvalds if (2 & (unsigned long) buff) { 941da177e4SLinus Torvalds result += *(unsigned short *) buff; 951da177e4SLinus Torvalds count--; 961da177e4SLinus Torvalds len -= 2; 971da177e4SLinus Torvalds buff += 2; 981da177e4SLinus Torvalds } 991da177e4SLinus Torvalds count >>= 1; /* nr of 32-bit words.. */ 1001da177e4SLinus Torvalds if (count) { 1011da177e4SLinus Torvalds if (4 & (unsigned long) buff) { 1021da177e4SLinus Torvalds result += *(unsigned int *) buff; 1031da177e4SLinus Torvalds count--; 1041da177e4SLinus Torvalds len -= 4; 1051da177e4SLinus Torvalds buff += 4; 1061da177e4SLinus Torvalds } 1071da177e4SLinus Torvalds count >>= 1; /* nr of 64-bit words.. */ 1081da177e4SLinus Torvalds if (count) { 1091da177e4SLinus Torvalds unsigned long carry = 0; 1101da177e4SLinus Torvalds do { 1111da177e4SLinus Torvalds unsigned long w = *(unsigned long *) buff; 1121da177e4SLinus Torvalds count--; 1131da177e4SLinus Torvalds buff += 8; 1141da177e4SLinus Torvalds result += carry; 1151da177e4SLinus Torvalds result += w; 1161da177e4SLinus Torvalds carry = (w > result); 1171da177e4SLinus Torvalds } while (count); 1181da177e4SLinus Torvalds result += carry; 1191da177e4SLinus Torvalds result = (result & 0xffffffff) + (result >> 32); 1201da177e4SLinus Torvalds } 1211da177e4SLinus Torvalds if (len & 4) { 1221da177e4SLinus Torvalds result += *(unsigned int *) buff; 1231da177e4SLinus Torvalds buff += 4; 1241da177e4SLinus Torvalds } 1251da177e4SLinus Torvalds } 1261da177e4SLinus Torvalds if (len & 2) { 1271da177e4SLinus Torvalds result += *(unsigned short *) buff; 1281da177e4SLinus Torvalds buff += 2; 1291da177e4SLinus Torvalds } 1301da177e4SLinus Torvalds } 1311da177e4SLinus Torvalds if (len & 1) 1321da177e4SLinus Torvalds result += *buff; 1331da177e4SLinus Torvalds result = from64to16(result); 1341da177e4SLinus Torvalds if (odd) 1351da177e4SLinus Torvalds result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); 1361da177e4SLinus Torvalds out: 1371da177e4SLinus Torvalds return result; 1381da177e4SLinus Torvalds } 1391da177e4SLinus Torvalds 1401da177e4SLinus Torvalds /* 1411da177e4SLinus Torvalds * This is a version of ip_compute_csum() optimized for IP headers, 1421da177e4SLinus Torvalds * which always checksum on 4 octet boundaries. 1431da177e4SLinus Torvalds */ 1449be259aaSAl Viro __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 1451da177e4SLinus Torvalds { 1469be259aaSAl Viro return (__force __sum16)~do_csum(iph,ihl*4); 1471da177e4SLinus Torvalds } 14800fc0e0dSAl Viro EXPORT_SYMBOL(ip_fast_csum); 1491da177e4SLinus Torvalds 1501da177e4SLinus Torvalds /* 1511da177e4SLinus Torvalds * computes the checksum of a memory block at buff, length len, 1521da177e4SLinus Torvalds * and adds in "sum" (32-bit) 1531da177e4SLinus Torvalds * 1541da177e4SLinus Torvalds * returns a 32-bit number suitable for feeding into itself 1551da177e4SLinus Torvalds * or csum_tcpudp_magic 1561da177e4SLinus Torvalds * 1571da177e4SLinus Torvalds * this function must be called with even lengths, except 1581da177e4SLinus Torvalds * for the last fragment, which may be odd 1591da177e4SLinus Torvalds * 1601da177e4SLinus Torvalds * it's best to have buff aligned on a 32-bit boundary 1611da177e4SLinus Torvalds */ 1629be259aaSAl Viro __wsum csum_partial(const void *buff, int len, __wsum sum) 1631da177e4SLinus Torvalds { 1641da177e4SLinus Torvalds unsigned long result = do_csum(buff, len); 1651da177e4SLinus Torvalds 1661da177e4SLinus Torvalds /* add in old sum, and carry.. */ 1679be259aaSAl Viro result += (__force u32)sum; 1681da177e4SLinus Torvalds /* 32+c bits -> 32 bits */ 1691da177e4SLinus Torvalds result = (result & 0xffffffff) + (result >> 32); 1709be259aaSAl Viro return (__force __wsum)result; 1711da177e4SLinus Torvalds } 1721da177e4SLinus Torvalds 1731da177e4SLinus Torvalds EXPORT_SYMBOL(csum_partial); 1741da177e4SLinus Torvalds 1751da177e4SLinus Torvalds /* 1761da177e4SLinus Torvalds * this routine is used for miscellaneous IP-like checksums, mainly 1771da177e4SLinus Torvalds * in icmp.c 1781da177e4SLinus Torvalds */ 1799be259aaSAl Viro __sum16 ip_compute_csum(const void *buff, int len) 1801da177e4SLinus Torvalds { 1819be259aaSAl Viro return (__force __sum16)~from64to16(do_csum(buff,len)); 1821da177e4SLinus Torvalds } 18300fc0e0dSAl Viro EXPORT_SYMBOL(ip_compute_csum); 184