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- /*
- * linux/include/asm-arm/checksum.h
- *
- * IP checksum routines
- *
- * Copyright (C) Original authors of ../asm-i386/checksum.h
- * Copyright (C) 1996,1997,1998 Russell King
- */
- #ifndef __ASM_ARM_CHECKSUM_H
- #define __ASM_ARM_CHECKSUM_H
-
- #ifndef __ASM_ARM_SEGMENT_H
- #include <asm/segment.h>
- #endif
-
- /*
- * 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
- */
- 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, and handles user-space pointer exceptions correctly, when needed.
- *
- * here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- */
-
- unsigned int
- csum_partial_copy_nocheck(const char *src, char *dst, int len, int sum);
-
- unsigned int
- csum_partial_copy_from_user(const char *src, char *dst, int len, int sum, int *err_ptr);
-
- #if 0
- /*
- * This combination is currently not used, but possible:
- */
- unsigned int
- csum_partial_copy_to_user(const char *src, char *dst, int len, int sum, int *err_ptr);
- #endif
-
- /*
- * These are the old (and unsafe) way of doing checksums, a warning message will be
- * printed if they are used and an exception occurs.
- *
- * these functions should go away after some time.
- */
- #define csum_partial_copy_fromuser csum_partial_copy
- unsigned int
- csum_partial_copy(const char *src, char *dst, int len, int sum);
-
- /*
- * This is a version of ip_compute_csum() optimized for IP headers,
- * which always checksum on 4 octet boundaries.
- *
- * Converted and optimised for ARM by R. M. King.
- *
- * Note: the order that the LDM registers are loaded with respect to
- * the adc's doesn't matter.
- */
- static inline unsigned short
- ip_fast_csum(unsigned char * iph, unsigned int ihl)
- {
- unsigned int sum, tmp1;
-
- __asm__ __volatile__("
- sub %2, %2, #5
- ldr %0, [%1], #4
- ldr %3, [%1], #4
- adds %0, %0, %3
- ldr %3, [%1], #4
- adcs %0, %0, %3
- ldr %3, [%1], #4
- adcs %0, %0, %3
- 1: ldr %3, [%1], #4
- adcs %0, %0, %3
- tst %2, #15
- subne %2, %2, #1
- bne 1b
- adc %0, %0, #0
- adds %0, %0, %0, lsl #16
- addcs %0, %0, #0x10000
- mvn %0, %0
- mov %0, %0, lsr #16
- "
- : "=&r" (sum), "=&r" (iph), "=&r" (ihl), "=&r" (tmp1)
- : "1" (iph), "2" (ihl));
- return(sum);
- }
-
- /*
- * Fold a partial checksum without adding pseudo headers
- */
- static inline unsigned int
- csum_fold(unsigned int sum)
- {
- __asm__("
- adds %0, %0, %0, lsl #16
- addcs %0, %0, #0x10000"
- : "=r" (sum)
- : "0" (sum));
- return (~sum) >> 16;
- }
-
- static inline unsigned long
- csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
- unsigned short proto, unsigned int sum)
- {
- __asm__("
- adds %0, %0, %1
- adcs %0, %0, %2
- adcs %0, %0, %3
- adc %0, %0, #0"
- : "=&r"(sum)
- : "r" (daddr), "r" (saddr), "r" ((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));
- }
-
-
- /*
- * this routine is used for miscellaneous IP-like checksums, mainly
- * in icmp.c
- */
- static inline unsigned short
- ip_compute_csum(unsigned char * buff, int len)
- {
- return csum_fold(csum_partial(buff, len, 0));
- }
-
- #define _HAVE_ARCH_IPV6_CSUM
- extern unsigned long
- __csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u32 len,
- __u32 proto, unsigned int sum);
-
- extern __inline__ unsigned short int
- csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u16 len,
- unsigned short proto, unsigned int sum)
- {
- return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl((__u32)len),
- htonl(proto), sum));
- }
- #endif
-