1 #ifndef _ALPHA_CHECKSUM_H 2 #define _ALPHA_CHECKSUM_H 3 4 5 /* 6 * This is a version of ip_compute_csum() optimized for IP headers, 7 * which always checksum on 4 octet boundaries. 8 */ 9 extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl); 10 11 /* 12 * computes the checksum of the TCP/UDP pseudo-header 13 * returns a 16-bit checksum, already complemented 14 */ 15 extern unsigned short int csum_tcpudp_magic(unsigned long saddr, 16 unsigned long daddr, 17 unsigned short len, 18 unsigned short proto, 19 unsigned int sum); 20 21 /* 22 * computes the checksum of a memory block at buff, length len, 23 * and adds in "sum" (32-bit) 24 * 25 * returns a 32-bit number suitable for feeding into itself 26 * or csum_tcpudp_magic 27 * 28 * this function must be called with even lengths, except 29 * for the last fragment, which may be odd 30 * 31 * it's best to have buff aligned on a 32-bit boundary 32 */ 33 extern unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum); 34 35 /* 36 * the same as csum_partial, but copies from src while it 37 * checksums 38 * 39 * here even more important to align src and dst on a 32-bit (or even 40 * better 64-bit) boundary 41 */ 42 unsigned int csum_partial_copy( const char *src, char *dst, int len, int sum); 43 44 /* 45 * the same as csum_partial, but copies from user space (but on the alpha 46 * we have just one address space, so this is identical to the above) 47 */ 48 #define csum_partial_copy_fromuser csum_partial_copy 49 50 51 /* 52 * this routine is used for miscellaneous IP-like checksums, mainly 53 * in icmp.c 54 */ 55 56 extern unsigned short ip_compute_csum(unsigned char * buff, int len); 57 58 /* 59 * Fold a partial checksum without adding pseudo headers 60 */ 61 62 static inline unsigned short csum_fold(unsigned int sum) /**/ 63 { 64 sum = (sum & 0xffff) + (sum >> 16); 65 sum = (sum & 0xffff) + (sum >> 16); 66 return ~sum; 67 } 68 69 #endif