1#ifndef _I386_CHECKSUM_H 2#define _I386_CHECKSUM_H 3 4 5/* 6 * computes the checksum of a memory block at buff, length len, 7 * and adds in "sum" (32-bit) 8 * 9 * returns a 32-bit number suitable for feeding into itself 10 * or csum_tcpudp_magic 11 * 12 * this function must be called with even lengths, except 13 * for the last fragment, which may be odd 14 * 15 * it's best to have buff aligned on a 32-bit boundary 16 */ 17asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum); 18 19/* 20 * the same as csum_partial, but copies from src while it 21 * checksums, and handles user-space pointer exceptions correctly, when needed. 22 * 23 * here even more important to align src and dst on a 32-bit (or even 24 * better 64-bit) boundary 25 */ 26 27asmlinkage unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int sum, 28 int *src_err_ptr, int *dst_err_ptr); 29 30/* 31 * Note: when you get a NULL pointer exception here this means someone 32 * passed in an incorrect kernel address to one of these functions. 33 * 34 * If you use these functions directly please don't forget the 35 * verify_area(). 36 */ 37static __inline__ 38unsigned int csum_partial_copy_nocheck ( const char *src, char *dst, 39 int len, int sum) 40{ 41 return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL); 42} 43 44static __inline__ 45unsigned int csum_partial_copy_from_user ( const char *src, char *dst, 46 int len, int sum, int *err_ptr) 47{ 48 return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL); 49} 50 51/* 52 * These are the old (and unsafe) way of doing checksums, a warning message will be 53 * printed if they are used and an exeption occurs. 54 * 55 * these functions should go away after some time. 56 */ 57 58#define csum_partial_copy_fromuser csum_partial_copy 59unsigned int csum_partial_copy( const char *src, char *dst, int len, int sum); 60 61/* 62 * This is a version of ip_compute_csum() optimized for IP headers, 63 * which always checksum on 4 octet boundaries. 64 * 65 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by 66 * Arnt Gulbrandsen. 67 */ 68static inline unsigned short ip_fast_csum(unsigned char * iph, 69 unsigned int ihl) 70{ 71 unsigned int sum; 72 73 __asm__ __volatile__( 74 "movl (%1), %0 ;\n" 75 "subl $4, %2 ;\n" 76 "jbe 2f ;\n" 77 "addl 4(%1), %0 ;\n" 78 "adcl 8(%1), %0 ;\n" 79 "adcl 12(%1), %0 ;\n" 80"1: adcl 16(%1), %0 ;\n" 81 "lea 4(%1), %1 ;\n" 82 "decl %2 ;\n" 83 "jne 1b ;\n" 84 "adcl $0, %0 ;\n" 85 "movl %0, %2 ;\n" 86 "shrl $16, %0 ;\n" 87 "addw %w2, %w0 ;\n" 88 "adcl $0, %0 ;\n" 89 "notl %0 ;\n" 90"2: ;\n" 91 /* Since the input registers which are loaded with iph and ipl 92 are modified, we must also specify them as outputs, or gcc 93 will assume they contain their original values. */ 94 : "=r" (sum), "=r" (iph), "=r" (ihl) 95 : "1" (iph), "2" (ihl)); 96 return(sum); 97} 98 99/* 100 * Fold a partial checksum 101 */ 102 103static inline unsigned int csum_fold(unsigned int sum) 104{ 105 __asm__( 106 "addl %1, %0 ;\n" 107 "adcl $0xffff, %0 ;\n" 108 : "=r" (sum) 109 : "r" (sum << 16), "0" (sum & 0xffff0000) 110 ); 111 return (~sum) >> 16; 112} 113 114static inline unsigned long csum_tcpudp_nofold(unsigned long saddr, 115 unsigned long daddr, 116 unsigned short len, 117 unsigned short proto, 118 unsigned int sum) 119{ 120 __asm__( 121 "addl %1, %0 ;\n" 122 "adcl %2, %0 ;\n" 123 "adcl %3, %0 ;\n" 124 "adcl $0, %0 ;\n" 125 : "=r" (sum) 126 : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum)); 127 return sum; 128} 129 130/* 131 * computes the checksum of the TCP/UDP pseudo-header 132 * returns a 16-bit checksum, already complemented 133 */ 134static inline unsigned short int csum_tcpudp_magic(unsigned long saddr, 135 unsigned long daddr, 136 unsigned short len, 137 unsigned short proto, 138 unsigned int sum) 139{ 140 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); 141} 142 143/* 144 * this routine is used for miscellaneous IP-like checksums, mainly 145 * in icmp.c 146 */ 147 148static inline unsigned short ip_compute_csum(unsigned char * buff, int len) 149{ 150 return csum_fold (csum_partial(buff, len, 0)); 151} 152 153#define _HAVE_ARCH_IPV6_CSUM 154static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr, 155 struct in6_addr *daddr, 156 __u32 len, 157 unsigned short proto, 158 unsigned int sum) 159{ 160 __asm__( 161 "addl 0(%1), %0 ;\n" 162 "adcl 4(%1), %0 ;\n" 163 "adcl 8(%1), %0 ;\n" 164 "adcl 12(%1), %0 ;\n" 165 "adcl 0(%2), %0 ;\n" 166 "adcl 4(%2), %0 ;\n" 167 "adcl 8(%2), %0 ;\n" 168 "adcl 12(%2), %0 ;\n" 169 "adcl %3, %0 ;\n" 170 "adcl %4, %0 ;\n" 171 "adcl $0, %0 ;\n" 172 : "=&r" (sum) 173 : "r" (saddr), "r" (daddr), 174 "r"(htonl(len)), "r"(htonl(proto)), "0"(sum)); 175 176 return csum_fold(sum); 177} 178 179/* 180 * Copy and checksum to user 181 */ 182#define HAVE_CSUM_COPY_USER 183static __inline__ unsigned int csum_and_copy_to_user(const char *src, char *dst, 184 int len, int sum, int *err_ptr) 185{ 186 if (access_ok(VERIFY_WRITE, dst, len)) 187 return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr); 188 189 if (len) 190 *err_ptr = -EFAULT; 191 192 return -1; /* invalid checksum */ 193} 194 195#endif 196