273 lines
6.4 KiB
C
273 lines
6.4 KiB
C
/*-
|
|
* Copyright (c) 2014 The FreeBSD Foundation
|
|
*
|
|
* This software was developed by John-Mark Gurney under
|
|
* the sponsorship of the FreeBSD Foundation and
|
|
* Rubicon Communications, LLC (Netgate).
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
*/
|
|
|
|
#include "gfmult.h"
|
|
|
|
#define REV_POLY_REDUCT 0xe1 /* 0x87 bit reversed */
|
|
|
|
/* reverse the bits of a nibble */
|
|
static const uint8_t nib_rev[] = {
|
|
0x0, 0x8, 0x4, 0xc, 0x2, 0xa, 0x6, 0xe,
|
|
0x1, 0x9, 0x5, 0xd, 0x3, 0xb, 0x7, 0xf,
|
|
};
|
|
|
|
/* calculate v * 2 */
|
|
static inline struct gf128
|
|
gf128_mulalpha(struct gf128 v)
|
|
{
|
|
uint64_t mask;
|
|
|
|
mask = !!(v.v[1] & 1);
|
|
mask = ~(mask - 1);
|
|
v.v[1] = (v.v[1] >> 1) | ((v.v[0] & 1) << 63);
|
|
v.v[0] = (v.v[0] >> 1) ^ ((mask & REV_POLY_REDUCT) << 56);
|
|
|
|
return v;
|
|
}
|
|
|
|
/*
|
|
* Generate a table for 0-16 * h. Store the results in the table w/ indexes
|
|
* bit reversed, and the words striped across the values.
|
|
*/
|
|
void
|
|
gf128_genmultable(struct gf128 h, struct gf128table *t)
|
|
{
|
|
struct gf128 tbl[16];
|
|
int i;
|
|
|
|
tbl[0] = MAKE_GF128(0, 0);
|
|
tbl[1] = h;
|
|
|
|
for (i = 2; i < 16; i += 2) {
|
|
tbl[i] = gf128_mulalpha(tbl[i / 2]);
|
|
tbl[i + 1] = gf128_add(tbl[i], h);
|
|
}
|
|
|
|
for (i = 0; i < 16; i++) {
|
|
t->a[nib_rev[i]] = tbl[i].v[0] >> 32;
|
|
t->b[nib_rev[i]] = tbl[i].v[0];
|
|
t->c[nib_rev[i]] = tbl[i].v[1] >> 32;
|
|
t->d[nib_rev[i]] = tbl[i].v[1];
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Generate tables containing h, h^2, h^3 and h^4, starting at 0.
|
|
*/
|
|
void
|
|
gf128_genmultable4(struct gf128 h, struct gf128table4 *t)
|
|
{
|
|
struct gf128 h2, h3, h4;
|
|
|
|
gf128_genmultable(h, &t->tbls[0]);
|
|
|
|
h2 = gf128_mul(h, &t->tbls[0]);
|
|
|
|
gf128_genmultable(h2, &t->tbls[1]);
|
|
|
|
h3 = gf128_mul(h, &t->tbls[1]);
|
|
gf128_genmultable(h3, &t->tbls[2]);
|
|
|
|
h4 = gf128_mul(h2, &t->tbls[1]);
|
|
gf128_genmultable(h4, &t->tbls[3]);
|
|
}
|
|
|
|
/*
|
|
* Read a row from the table.
|
|
*/
|
|
static inline struct gf128
|
|
readrow(struct gf128table *tbl, unsigned bits)
|
|
{
|
|
struct gf128 r;
|
|
|
|
bits = bits % 16;
|
|
|
|
r.v[0] = ((uint64_t)tbl->a[bits] << 32) | tbl->b[bits];
|
|
r.v[1] = ((uint64_t)tbl->c[bits] << 32) | tbl->d[bits];
|
|
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* These are the reduction values. Since we are dealing with bit reversed
|
|
* version, the values need to be bit reversed, AND the indexes are also
|
|
* bit reversed to make lookups quicker.
|
|
*/
|
|
static uint16_t reduction[] = {
|
|
0x0000, 0x1c20, 0x3840, 0x2460, 0x7080, 0x6ca0, 0x48c0, 0x54e0,
|
|
0xe100, 0xfd20, 0xd940, 0xc560, 0x9180, 0x8da0, 0xa9c0, 0xb5e0,
|
|
};
|
|
|
|
/*
|
|
* Calculate:
|
|
* (x*2^4 + word[3,0]*h) *
|
|
* 2^4 + word[7,4]*h) *
|
|
* ...
|
|
* 2^4 + word[63,60]*h
|
|
*/
|
|
static struct gf128
|
|
gfmultword(uint64_t word, struct gf128 x, struct gf128table *tbl)
|
|
{
|
|
struct gf128 row;
|
|
unsigned bits;
|
|
unsigned redbits;
|
|
int i;
|
|
|
|
for (i = 0; i < 64; i += 4) {
|
|
bits = word % 16;
|
|
|
|
/* fetch row */
|
|
row = readrow(tbl, bits);
|
|
|
|
/* x * 2^4 */
|
|
redbits = x.v[1] % 16;
|
|
x.v[1] = (x.v[1] >> 4) | (x.v[0] % 16) << 60;
|
|
x.v[0] >>= 4;
|
|
x.v[0] ^= (uint64_t)reduction[redbits] << (64 - 16);
|
|
|
|
word >>= 4;
|
|
|
|
x = gf128_add(x, row);
|
|
}
|
|
|
|
return x;
|
|
}
|
|
|
|
/*
|
|
* Calculate
|
|
* (x*2^4 + worda[3,0]*h^4+wordb[3,0]*h^3+...+wordd[3,0]*h) *
|
|
* ...
|
|
* 2^4 + worda[63,60]*h^4+ ... + wordd[63,60]*h
|
|
*
|
|
* Passing/returning struct is .5% faster than passing in via pointer on
|
|
* amd64.
|
|
*/
|
|
static struct gf128
|
|
gfmultword4(uint64_t worda, uint64_t wordb, uint64_t wordc, uint64_t wordd,
|
|
struct gf128 x, struct gf128table4 *tbl)
|
|
{
|
|
struct gf128 rowa, rowb, rowc, rowd;
|
|
unsigned bitsa, bitsb, bitsc, bitsd;
|
|
unsigned redbits;
|
|
int i;
|
|
|
|
/*
|
|
* XXX - nibble reverse words to save a shift? probably not as
|
|
* nibble reverse would take 20 ops (5 * 4) verse 16
|
|
*/
|
|
|
|
for (i = 0; i < 64; i += 4) {
|
|
bitsa = worda % 16;
|
|
bitsb = wordb % 16;
|
|
bitsc = wordc % 16;
|
|
bitsd = wordd % 16;
|
|
|
|
/* fetch row */
|
|
rowa = readrow(&tbl->tbls[3], bitsa);
|
|
rowb = readrow(&tbl->tbls[2], bitsb);
|
|
rowc = readrow(&tbl->tbls[1], bitsc);
|
|
rowd = readrow(&tbl->tbls[0], bitsd);
|
|
|
|
/* x * 2^4 */
|
|
redbits = x.v[1] % 16;
|
|
x.v[1] = (x.v[1] >> 4) | (x.v[0] % 16) << 60;
|
|
x.v[0] >>= 4;
|
|
x.v[0] ^= (uint64_t)reduction[redbits] << (64 - 16);
|
|
|
|
worda >>= 4;
|
|
wordb >>= 4;
|
|
wordc >>= 4;
|
|
wordd >>= 4;
|
|
|
|
x = gf128_add(x, gf128_add(rowa, gf128_add(rowb,
|
|
gf128_add(rowc, rowd))));
|
|
}
|
|
|
|
return x;
|
|
}
|
|
|
|
struct gf128
|
|
gf128_mul(struct gf128 v, struct gf128table *tbl)
|
|
{
|
|
struct gf128 ret;
|
|
|
|
ret = MAKE_GF128(0, 0);
|
|
|
|
ret = gfmultword(v.v[1], ret, tbl);
|
|
ret = gfmultword(v.v[0], ret, tbl);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Calculate a*h^4 + b*h^3 + c*h^2 + d*h, or:
|
|
* (((a*h+b)*h+c)*h+d)*h
|
|
*/
|
|
struct gf128
|
|
gf128_mul4(struct gf128 a, struct gf128 b, struct gf128 c, struct gf128 d,
|
|
struct gf128table4 *tbl)
|
|
{
|
|
struct gf128 tmp;
|
|
|
|
tmp = MAKE_GF128(0, 0);
|
|
|
|
tmp = gfmultword4(a.v[1], b.v[1], c.v[1], d.v[1], tmp, tbl);
|
|
tmp = gfmultword4(a.v[0], b.v[0], c.v[0], d.v[0], tmp, tbl);
|
|
|
|
return tmp;
|
|
}
|
|
|
|
/*
|
|
* a = data[0..15] + r
|
|
* b = data[16..31]
|
|
* c = data[32..47]
|
|
* d = data[48..63]
|
|
*
|
|
* Calculate a*h^4 + b*h^3 + c*h^2 + d*h, or:
|
|
* (((a*h+b)*h+c)*h+d)*h
|
|
*/
|
|
struct gf128
|
|
gf128_mul4b(struct gf128 r, const uint8_t *v, struct gf128table4 *tbl)
|
|
{
|
|
struct gf128 a, b, c, d;
|
|
struct gf128 tmp;
|
|
|
|
tmp = MAKE_GF128(0, 0);
|
|
|
|
a = gf128_add(r, gf128_read(&v[0*16]));
|
|
b = gf128_read(&v[1*16]);
|
|
c = gf128_read(&v[2*16]);
|
|
d = gf128_read(&v[3*16]);
|
|
|
|
tmp = gfmultword4(a.v[1], b.v[1], c.v[1], d.v[1], tmp, tbl);
|
|
tmp = gfmultword4(a.v[0], b.v[0], c.v[0], d.v[0], tmp, tbl);
|
|
|
|
return tmp;
|
|
}
|