include/asm-x86_64/checksum.h

   1 #ifndef _X86_64_CHECKSUM_H
   2 #define _X86_64_CHECKSUM_H
   3
   4 /*
   5  * Checksums for x86-64
   6  * Copyright 2002 by Andi Kleen, SuSE Labs
   7  * with some code from asm-i386/checksum.h
   8  */
   9
  10 #include <linux/compiler.h>
  11 #include <asm/uaccess.h>
  12 #include <asm/byteorder.h>
  13
  14 /**
  15  * csum_fold - Fold and invert a 32bit checksum.
  16  * sum: 32bit unfolded sum
  17  *
  18  * Fold a 32bit running checksum to 16bit and invert it. This is usually
  19  * the last step before putting a checksum into a packet.
  20  * Make sure not to mix with 64bit checksums.
  21  */
  22 static inline unsigned int csum_fold(unsigned int sum)
  23 {
  24         __asm__(
  25                 "  addl %1,%0\n"
  26                 "  adcl $0xffff,%0"
  27                 : "=r" (sum)
  28                 : "r" (sum << 16), "0" (sum & 0xffff0000)
  29         );
  30         return (~sum) >> 16;
  31 }
  32
  33 /*
  34  *      This is a version of ip_compute_csum() optimized for IP headers,
  35  *      which always checksum on 4 octet boundaries.
  36  *
  37  *      By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
  38  *      Arnt Gulbrandsen.
  39  */
  40
  41 /**
  42  * ip_fast_csum - Compute the IPv4 header checksum efficiently.
  43  * iph: ipv4 header
  44  * ihl: length of header / 4
  45  */
  46 static inline unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
  47 {
  48         unsigned int sum;
  49
  50         asm(    "  movl (%1), %0\n"
  51                 "  subl $4, %2\n"
  52                 "  jbe 2f\n"
  53                 "  addl 4(%1), %0\n"
  54                 "  adcl 8(%1), %0\n"
  55                 "  adcl 12(%1), %0\n"
  56                 "1: adcl 16(%1), %0\n"
  57                 "  lea 4(%1), %1\n"
  58                 "  decl %2\n"
  59                 "  jne  1b\n"
  60                 "  adcl $0, %0\n"
  61                 "  movl %0, %2\n"
  62                 "  shrl $16, %0\n"
  63                 "  addw %w2, %w0\n"
  64                 "  adcl $0, %0\n"
  65                 "  notl %0\n"
  66                 "2:"
  67         /* Since the input registers which are loaded with iph and ipl
  68            are modified, we must also specify them as outputs, or gcc
  69            will assume they contain their original values. */
  70         : "=r" (sum), "=r" (iph), "=r" (ihl)
  71         : "1" (iph), "2" (ihl)
  72         : "memory");
  73         return(sum);
  74 }
  75
  76 /**
  77  * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
  78  * @saddr: source address
  79  * @daddr: destination address
  80  * @len: length of packet
  81  * @proto: ip protocol of packet
  82  * @sum: initial sum to be added in (32bit unfolded)
  83  *
  84  * Returns the pseudo header checksum the input data. Result is
  85  * 32bit unfolded.
  86  */
  87 static inline unsigned long
  88 csum_tcpudp_nofold(unsigned saddr, unsigned daddr, unsigned short len,
  89                    unsigned short proto, unsigned int sum)
  90 {
  91         asm("  addl %1, %0\n"
  92             "  adcl %2, %0\n"
  93             "  adcl %3, %0\n"
  94             "  adcl $0, %0\n"
  95                 : "=r" (sum)
  96             : "g" (daddr), "g" (saddr), "g" ((ntohs(len)<<16)+proto*256), "0" (sum));
  97     return sum;
  98 }
  99
 100
 101 /**
 102  * csum_tcpup_magic - Compute an IPv4 pseudo header checksum.
 103  * @saddr: source address
 104  * @daddr: destination address
 105  * @len: length of packet
 106  * @proto: ip protocol of packet
 107  * @sum: initial sum to be added in (32bit unfolded)
 108  *
 109  * Returns the 16bit pseudo header checksum the input data already
 110  * complemented and ready to be filled in.
 111  */
 112 static inline unsigned short int
 113 csum_tcpudp_magic(unsigned long saddr, unsigned long daddr,
 114                   unsigned short len, unsigned short proto, unsigned int sum)
 115 {
 116         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 117 }
 118
 119 /**
 120  * csum_partial - Compute an internet checksum.
 121  * @buff: buffer to be checksummed
 122  * @len: length of buffer.
 123  * @sum: initial sum to be added in (32bit unfolded)
 124  *
 125  * Returns the 32bit unfolded internet checksum of the buffer.
 126  * Before filling it in it needs to be csum_fold()'ed.
 127  * buff should be aligned to a 64bit boundary if possible.
 128  */
 129 extern unsigned int csum_partial(const unsigned char *buff, unsigned len, unsigned int sum);
 130
 131 #define  _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1
 132 #define HAVE_CSUM_COPY_USER 1
 133
 134
 135 /* Do not call this directly. Use the wrappers below */
 136 extern unsigned long csum_partial_copy_generic(const unsigned char *src, const unsigned char *dst,
 137                                                unsigned len,
 138                                                unsigned sum,
 139                                                int *src_err_ptr, int *dst_err_ptr);
 140
 141
 142 extern unsigned int csum_partial_copy_from_user(const unsigned char __user *src, unsigned char *dst,
 143                                        int len, unsigned int isum, int *errp);
 144 extern unsigned int csum_partial_copy_to_user(const unsigned char *src, unsigned char __user *dst,
 145                                       int len, unsigned int isum, int *errp);
 146 extern unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, int len,
 147                                               unsigned int sum);
 148
 149 /* Old names. To be removed. */
 150 #define csum_and_copy_to_user csum_partial_copy_to_user
 151 #define csum_and_copy_from_user csum_partial_copy_from_user
 152
 153 /**
 154  * ip_compute_csum - Compute an 16bit IP checksum.
 155  * @buff: buffer address.
 156  * @len: length of buffer.
 157  *
 158  * Returns the 16bit folded/inverted checksum of the passed buffer.
 159  * Ready to fill in.
 160  */
 161 extern unsigned short ip_compute_csum(unsigned char * buff, int len);
 162
 163 /**
 164  * csum_ipv6_magic - Compute checksum of an IPv6 pseudo header.
 165  * @saddr: source address
 166  * @daddr: destination address
 167  * @len: length of packet
 168  * @proto: protocol of packet
 169  * @sum: initial sum (32bit unfolded) to be added in
 170  *
 171  * Computes an IPv6 pseudo header checksum. This sum is added the checksum
 172  * into UDP/TCP packets and contains some link layer information.
 173  * Returns the unfolded 32bit checksum.
 174  */
 175
 176 struct in6_addr;
 177
 178 #define _HAVE_ARCH_IPV6_CSUM 1
 179 extern unsigned short
 180 csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr,
 181                 __u32 len, unsigned short proto, unsigned int sum);
 182
 183 static inline unsigned add32_with_carry(unsigned a, unsigned b)
 184 {
 185         asm("addl %2,%0\n\t"
 186             "adcl $0,%0"
 187             : "=r" (a)
 188             : "0" (a), "r" (b));
 189         return a;
 190 }
 191
 192 #endif
 193