#ifndef _X86_64_CHECKSUM_H #define _X86_64_CHECKSUM_H /* * This is a version of ip_compute_csum() optimized for IP headers, * which always checksum on 4 octet boundaries. * * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by * Arnt Gulbrandsen. */ static inline unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl) { unsigned int sum; __asm__ __volatile__( "\n movl (%1), %0" "\n subl $4, %2" "\n jbe 2f" "\n addl 4(%1), %0" "\n adcl 8(%1), %0" "\n adcl 12(%1), %0" "\n1: adcl 16(%1), %0" "\n lea 4(%1), %1" "\n decl %2" "\n jne 1b" "\n adcl $0, %0" "\n movl %0, %2" "\n shrl $16, %0" "\n addw %w2, %w0" "\n adcl $0, %0" "\n notl %0" "\n2:" /* Since the input registers which are loaded with iph and ipl are modified, we must also specify them as outputs, or gcc will assume they contain their original values. */ : "=r" (sum), "=r" (iph), "=r" (ihl) : "1" (iph), "2" (ihl)); return(sum); } /* * Fold a partial checksum. Note this works on a 32bit unfolded checksum. Make sure * to not mix with 64bit checksums! */ static inline unsigned int csum_fold(unsigned int sum) { __asm__( "\n addl %1,%0" "\n adcl $0xffff,%0" : "=r" (sum) : "r" (sum << 16), "0" (sum & 0xffff0000) ); return (~sum) >> 16; } static inline unsigned long csum_tcpudp_nofold(unsigned saddr, unsigned daddr, unsigned short len, unsigned short proto, unsigned int sum) { __asm__( "\n addl %1, %0" "\n adcl %2, %0" "\n adcl %3, %0" "\n adcl $0, %0" : "=r" (sum) : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum)); return sum; } /* * computes the checksum of the TCP/UDP pseudo-header * returns a 16-bit checksum, already complemented */ static inline unsigned short int csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len, unsigned short proto, unsigned int sum) { return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,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); /* * the same as csum_partial, but copies from src while it * checksums * * here even more important to align src and dst on a 32-bit (or even * better 64-bit) boundary */ unsigned int csum_partial_copy(const char *src, char *dst, int len, unsigned int sum); /* * this is a new version of the above that records errors it finds in *errp, * but continues and zeros the rest of the buffer. */ unsigned int csum_partial_copy_from_user(const char *src, char *dst, int len, unsigned int sum, int *errp); unsigned int csum_partial_copy_nocheck(const char *src, char *dst, int len, unsigned int sum); /* * this routine is used for miscellaneous IP-like checksums, mainly * in icmp.c */ extern unsigned short ip_compute_csum(unsigned char * buff, int len); #define _HAVE_ARCH_IPV6_CSUM static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u32 len, unsigned short proto, unsigned int sum) { __asm__( "\n addl 0(%1), %0" "\n adcl 4(%1), %0" "\n adcl 8(%1), %0" "\n adcl 12(%1), %0" "\n adcl 0(%2), %0" "\n adcl 4(%2), %0" "\n adcl 8(%2), %0" "\n adcl 12(%2), %0" "\n adcl %3, %0" "\n adcl %4, %0" "\n adcl $0, %0" : "=&r" (sum) : "r" (saddr), "r" (daddr), "r"(htonl(len)), "r"(htonl(proto)), "0"(sum)); return csum_fold(sum); } #endif