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 __sum16 csum_fold(__wsum sum)
  23 {
  24         __asm__(
  25                 "  addl %1,%0\n"
  26                 "  adcl $0xffff,%0"
  27                 : "=r" (sum)
  28                 : "r" ((__force u32)sum << 16),
  29                   "0" ((__force u32)sum & 0xffff0000)
  30         );
  31         return (__force __sum16)(~(__force u32)sum >> 16);
  32 }
  33
  34 /*
  35  *      This is a version of ip_compute_csum() optimized for IP headers,
  36  *      which always checksum on 4 octet boundaries.
  37  *
  38  *      By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
  39  *      Arnt Gulbrandsen.
  40  */
  41
  42 /**
  43  * ip_fast_csum - Compute the IPv4 header checksum efficiently.
  44  * iph: ipv4 header
  45  * ihl: length of header / 4
  46  */
  47 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  48 {
  49         unsigned int sum;
  50
  51         asm(    "  movl (%1), %0\n"
  52                 "  subl $4, %2\n"
  53                 "  jbe 2f\n"
  54                 "  addl 4(%1), %0\n"
  55                 "  adcl 8(%1), %0\n"
  56                 "  adcl 12(%1), %0\n"
  57                 "1: adcl 16(%1), %0\n"
  58                 "  lea 4(%1), %1\n"
  59                 "  decl %2\n"
  60                 "  jne  1b\n"
  61                 "  adcl $0, %0\n"
  62                 "  movl %0, %2\n"
  63                 "  shrl $16, %0\n"
  64                 "  addw %w2, %w0\n"
  65                 "  adcl $0, %0\n"
  66                 "  notl %0\n"
  67                 "2:"
  68         /* Since the input registers which are loaded with iph and ihl
  69            are modified, we must also specify them as outputs, or gcc
  70            will assume they contain their original values. */
  71         : "=r" (sum), "=r" (iph), "=r" (ihl)
  72         : "1" (iph), "2" (ihl)
  73         : "memory");
  74         return (__force __sum16)sum;
  75 }
  76
  77 /**
  78  * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
  79  * @saddr: source address
  80  * @daddr: destination address
  81  * @len: length of packet
  82  * @proto: ip protocol of packet
  83  * @sum: initial sum to be added in (32bit unfolded)
  84  *
  85  * Returns the pseudo header checksum the input data. Result is
  86  * 32bit unfolded.
  87  */
  88 static inline __wsum
  89 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
  90                    unsigned short proto, __wsum sum)
  91 {
  92         asm("  addl %1, %0\n"
  93             "  adcl %2, %0\n"
  94             "  adcl %3, %0\n"
  95             "  adcl $0, %0\n"
  96                 : "=r" (sum)
  97             : "g" (daddr), "g" (saddr),
  98               "g" ((len + proto)<<8), "0" (sum));
  99     return sum;
 100 }
 101
 102
 103 /**
 104  * csum_tcpup_magic - Compute an IPv4 pseudo header checksum.
 105  * @saddr: source address
 106  * @daddr: destination address
 107  * @len: length of packet
 108  * @proto: ip protocol of packet
 109  * @sum: initial sum to be added in (32bit unfolded)
 110  *
 111  * Returns the 16bit pseudo header checksum the input data already
 112  * complemented and ready to be filled in.
 113  */
 114 static inline __sum16
 115 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 116                   unsigned short len, unsigned short proto, __wsum sum)
 117 {
 118         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 119 }
 120
 121 /**
 122  * csum_partial - Compute an internet checksum.
 123  * @buff: buffer to be checksummed
 124  * @len: length of buffer.
 125  * @sum: initial sum to be added in (32bit unfolded)
 126  *
 127  * Returns the 32bit unfolded internet checksum of the buffer.
 128  * Before filling it in it needs to be csum_fold()'ed.
 129  * buff should be aligned to a 64bit boundary if possible.
 130  */
 131 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 132
 133 #define  _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1
 134 #define HAVE_CSUM_COPY_USER 1
 135
 136
 137 /* Do not call this directly. Use the wrappers below */
 138 extern __wsum csum_partial_copy_generic(const void *src, const void *dst,
 139                                                int len,
 140                                                __wsum sum,
 141                                                int *src_err_ptr, int *dst_err_ptr);
 142
 143
 144 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
 145                                        int len, __wsum isum, int *errp);
 146 extern __wsum csum_partial_copy_to_user(const void *src, void __user *dst,
 147                                       int len, __wsum isum, int *errp);
 148 extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len,
 149                                               __wsum sum);
 150
 151 /* Old names. To be removed. */
 152 #define csum_and_copy_to_user csum_partial_copy_to_user
 153 #define csum_and_copy_from_user csum_partial_copy_from_user
 154
 155 /**
 156  * ip_compute_csum - Compute an 16bit IP checksum.
 157  * @buff: buffer address.
 158  * @len: length of buffer.
 159  *
 160  * Returns the 16bit folded/inverted checksum of the passed buffer.
 161  * Ready to fill in.
 162  */
 163 extern __sum16 ip_compute_csum(const void *buff, int len);
 164
 165 /**
 166  * csum_ipv6_magic - Compute checksum of an IPv6 pseudo header.
 167  * @saddr: source address
 168  * @daddr: destination address
 169  * @len: length of packet
 170  * @proto: protocol of packet
 171  * @sum: initial sum (32bit unfolded) to be added in
 172  *
 173  * Computes an IPv6 pseudo header checksum. This sum is added the checksum
 174  * into UDP/TCP packets and contains some link layer information.
 175  * Returns the unfolded 32bit checksum.
 176  */
 177
 178 struct in6_addr;
 179
 180 #define _HAVE_ARCH_IPV6_CSUM 1
 181 extern __sum16
 182 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
 183                 __u32 len, unsigned short proto, __wsum sum);
 184
 185 static inline unsigned add32_with_carry(unsigned a, unsigned b)
 186 {
 187         asm("addl %2,%0\n\t"
 188             "adcl $0,%0"
 189             : "=r" (a)
 190             : "0" (a), "r" (b));
 191         return a;
 192 }
 193
 194 #endif
 195