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9b6ef21e51
(And don't try to go beyond fletcher checksum offset special value.) Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
588 lines
12 KiB
C
588 lines
12 KiB
C
/*
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* Copyright (C) 2008 Sun Microsystems, Inc.
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*
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* This file is part of Quagga.
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*
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* Quagga is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* Quagga is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; see the file COPYING; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <zebra.h>
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#include <stdlib.h>
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#include <time.h>
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#include "checksum.h"
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#include "network.h"
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#include "prng.h"
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struct thread_master *master;
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struct acc_vals {
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int c0;
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int c1;
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};
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struct csum_vals {
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struct acc_vals a;
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int x;
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int y;
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};
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static struct csum_vals ospfd_vals, isisd_vals;
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typedef size_t testsz_t;
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typedef uint16_t testoff_t;
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/* Fletcher Checksum -- Refer to RFC1008. */
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#define MODX 4102U
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/* The final reduction phase.
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* This one should be the original ospfd version
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*/
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static uint16_t reduce_ospfd(struct csum_vals *vals, testsz_t len,
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testoff_t off)
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{
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#define x vals->x
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#define y vals->y
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#define c0 vals->a.c0
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#define c1 vals->a.c1
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x = ((len - off - 1) * c0 - c1) % 255;
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if (x <= 0)
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x += 255;
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y = 510 - c0 - x;
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if (y > 255)
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y -= 255;
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/* take care endian issue. */
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return htons((x << 8) + y);
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#undef x
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#undef y
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#undef c0
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#undef c1
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}
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/* slightly different concatenation */
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static uint16_t reduce_ospfd1(struct csum_vals *vals, testsz_t len,
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testoff_t off)
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{
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#define x vals->x
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#define y vals->y
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#define c0 vals->a.c0
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#define c1 vals->a.c1
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x = ((len - off - 1) * c0 - c1) % 255;
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if (x <= 0)
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x += 255;
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y = 510 - c0 - x;
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if (y > 255)
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y -= 255;
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/* take care endian issue. */
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return htons((x << 8) | (y & 0xff));
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#undef x
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#undef y
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#undef c0
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#undef c1
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}
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/* original isisd version */
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static uint16_t reduce_isisd(struct csum_vals *vals, testsz_t len,
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testoff_t off)
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{
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#define x vals->x
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#define y vals->y
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#define c0 vals->a.c0
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#define c1 vals->a.c1
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uint32_t mul;
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mul = (len - off) * (c0);
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x = mul - c0 - c1;
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y = c1 - mul - 1;
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if (y > 0)
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y++;
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if (x < 0)
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x--;
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x %= 255;
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y %= 255;
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if (x == 0)
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x = 255;
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if (y == 0)
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y = 1;
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return htons((x << 8) | (y & 0xff));
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#undef x
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#undef y
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#undef c0
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#undef c1
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}
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/* Is the -1 in y wrong perhaps? */
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static uint16_t reduce_isisd_yfix(struct csum_vals *vals, testsz_t len,
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testoff_t off)
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{
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#define x vals->x
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#define y vals->y
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#define c0 vals->a.c0
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#define c1 vals->a.c1
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uint32_t mul;
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mul = (len - off) * (c0);
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x = mul - c0 - c1;
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y = c1 - mul;
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if (y > 0)
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y++;
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if (x < 0)
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x--;
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x %= 255;
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y %= 255;
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if (x == 0)
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x = 255;
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if (y == 0)
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y = 1;
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return htons((x << 8) | (y & 0xff));
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#undef x
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#undef y
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#undef c0
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#undef c1
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}
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/* Move the mods yp */
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static uint16_t reduce_isisd_mod(struct csum_vals *vals, testsz_t len,
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testoff_t off)
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{
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#define x vals->x
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#define y vals->y
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#define c0 vals->a.c0
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#define c1 vals->a.c1
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uint32_t mul;
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mul = (len - off) * (c0);
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x = mul - c1 - c0;
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y = c1 - mul - 1;
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x %= 255;
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y %= 255;
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if (y > 0)
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y++;
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if (x < 0)
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x--;
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if (x == 0)
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x = 255;
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if (y == 0)
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y = 1;
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return htons((x << 8) | (y & 0xff));
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#undef x
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#undef y
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#undef c0
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#undef c1
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}
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/* Move the mods up + fix y */
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static uint16_t reduce_isisd_mody(struct csum_vals *vals, testsz_t len,
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testoff_t off)
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{
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#define x vals->x
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#define y vals->y
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#define c0 vals->a.c0
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#define c1 vals->a.c1
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uint32_t mul;
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mul = (len - off) * (c0);
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x = mul - c0 - c1;
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y = c1 - mul;
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x %= 255;
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y %= 255;
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if (y > 0)
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y++;
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if (x < 0)
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x--;
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if (x == 0)
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x = 255;
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if (y == 0)
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y = 1;
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return htons((x << 8) | (y & 0xff));
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#undef x
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#undef y
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#undef c0
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#undef c1
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}
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struct reductions_t {
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const char *name;
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uint16_t (*f)(struct csum_vals *, testsz_t, testoff_t);
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} reducts[] = {
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{.name = "ospfd", .f = reduce_ospfd},
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{.name = "ospfd-1", .f = reduce_ospfd1},
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{.name = "isisd", .f = reduce_isisd},
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{.name = "isisd-yfix", .f = reduce_isisd_yfix},
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{.name = "isisd-mod", .f = reduce_isisd_mod},
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{.name = "isisd-mody", .f = reduce_isisd_mody},
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{NULL, NULL},
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};
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/* The original ospfd checksum */
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static uint16_t ospfd_checksum(uint8_t *buffer, testsz_t len, testoff_t off)
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{
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uint8_t *sp, *ep, *p, *q;
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int c0 = 0, c1 = 0;
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int x, y;
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uint16_t checksum, *csum;
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csum = (uint16_t *)(buffer + off);
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*(csum) = 0;
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sp = buffer;
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for (ep = sp + len; sp < ep; sp = q) {
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q = sp + MODX;
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if (q > ep)
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q = ep;
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for (p = sp; p < q; p++) {
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c0 += *p;
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c1 += c0;
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}
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c0 %= 255;
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c1 %= 255;
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}
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ospfd_vals.a.c0 = c0;
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ospfd_vals.a.c1 = c1;
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// printf ("%s: len %u, off %u, c0 %d, c1 %d\n",
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// __func__, len, off, c0, c1);
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x = ((int)(len - off - 1) * (int)c0 - (int)c1) % 255;
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if (x <= 0)
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x += 255;
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y = 510 - c0 - x;
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if (y > 255)
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y -= 255;
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ospfd_vals.x = x;
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ospfd_vals.y = y;
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buffer[off] = x;
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buffer[off + 1] = y;
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/* take care endian issue. */
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checksum = htons((x << 8) | (y & 0xff));
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return (checksum);
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}
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/* the original, broken isisd checksum */
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static uint16_t iso_csum_create(uint8_t *buffer, testsz_t len, testoff_t off)
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{
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uint8_t *p;
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int x;
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int y;
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uint32_t mul;
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uint32_t c0;
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uint32_t c1;
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uint16_t checksum, *csum;
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int i, init_len, partial_len;
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checksum = 0;
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csum = (uint16_t *)(buffer + off);
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*(csum) = checksum;
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p = buffer;
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c0 = 0;
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c1 = 0;
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init_len = len;
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while (len != 0) {
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partial_len = MIN(len, MODX);
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for (i = 0; i < partial_len; i++) {
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c0 = c0 + *(p++);
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c1 += c0;
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}
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c0 = c0 % 255;
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c1 = c1 % 255;
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len -= partial_len;
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}
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isisd_vals.a.c0 = c0;
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isisd_vals.a.c1 = c1;
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mul = (init_len - off) * c0;
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x = mul - c1 - c0;
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y = c1 - mul - 1;
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if (y > 0)
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y++;
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if (x < 0)
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x--;
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x %= 255;
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y %= 255;
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if (x == 0)
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x = 255;
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if (y == 0)
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y = 1;
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isisd_vals.x = x;
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isisd_vals.y = y;
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checksum = htons((x << 8) | (y & 0xFF));
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*(csum) = checksum;
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/* return the checksum for user usage */
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return checksum;
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}
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static int verify(uint8_t *buffer, testsz_t len)
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{
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uint8_t *p;
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uint32_t c0;
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uint32_t c1;
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int i, partial_len;
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p = buffer;
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c0 = 0;
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c1 = 0;
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while (len) {
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partial_len = MIN(len, 5803U);
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for (i = 0; i < partial_len; i++) {
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c0 = c0 + *(p++);
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c1 += c0;
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}
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c0 = c0 % 255;
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c1 = c1 % 255;
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len -= partial_len;
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}
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if (c0 == 0 && c1 == 0)
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return 0;
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return 1;
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}
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static int /* return checksum in low-order 16 bits */
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in_cksum_optimized(void *parg, int nbytes)
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{
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unsigned short *ptr = parg;
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register long sum; /* assumes long == 32 bits */
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register unsigned short answer; /* assumes unsigned short == 16 bits */
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register int count;
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/*
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* Our algorithm is simple, using a 32-bit accumulator (sum),
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* we add sequential 16-bit words to it, and at the end, fold back
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* all the carry bits from the top 16 bits into the lower 16 bits.
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*/
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sum = 0;
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count = nbytes >> 1; /* div by 2 */
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for (ptr--; count; --count)
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sum += *++ptr;
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if (nbytes & 1) /* Odd */
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sum += *(uint8_t *)(++ptr); /* one byte only */
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/*
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* Add back carry outs from top 16 bits to low 16 bits.
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*/
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sum = (sum >> 16) + (sum & 0xffff); /* add high-16 to low-16 */
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sum += (sum >> 16); /* add carry */
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answer = ~sum; /* ones-complement, then truncate to 16 bits */
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return (answer);
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}
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static int /* return checksum in low-order 16 bits */
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in_cksum_rfc(void *parg, int count)
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/* from RFC 1071 */
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{
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unsigned short *addr = parg;
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/* Compute Internet Checksum for "count" bytes
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* beginning at location "addr".
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*/
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register long sum = 0;
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while (count > 1) {
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/* This is the inner loop */
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sum += *addr++;
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count -= 2;
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}
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/* Add left-over byte, if any */
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if (count > 0) {
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sum += *(uint8_t *)addr;
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}
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/* Fold 32-bit sum to 16 bits */
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while (sum >> 16)
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sum = (sum & 0xffff) + (sum >> 16);
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return ~sum;
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}
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int main(int argc, char **argv)
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{
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/* 60017 65629 702179 */
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#define MAXDATALEN 60017
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#define BUFSIZE MAXDATALEN + sizeof(uint16_t)
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uint8_t buffer[BUFSIZE];
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int exercise = 0;
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#define EXERCISESTEP 257
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struct prng *prng = prng_new(0);
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while (1) {
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uint16_t ospfd, isisd, lib, in_csum, in_csum_res, in_csum_rfc;
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int i;
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exercise += EXERCISESTEP;
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exercise %= MAXDATALEN;
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printf("\rexercising length %d\033[K", exercise);
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for (i = 0; i < exercise; i++)
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buffer[i] = prng_rand(prng);
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in_csum = in_cksum(buffer, exercise);
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in_csum_res = in_cksum_optimized(buffer, exercise);
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in_csum_rfc = in_cksum_rfc(buffer, exercise);
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if (in_csum_res != in_csum || in_csum != in_csum_rfc)
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printf("\nverify: in_chksum failed in_csum:%x, in_csum_res:%x,in_csum_rfc %x, len:%d\n",
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in_csum, in_csum_res, in_csum_rfc, exercise);
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struct iovec iov[3];
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uint16_t in_csum_iov;
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iov[0].iov_base = buffer;
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iov[0].iov_len = exercise / 2;
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iov[1].iov_base = buffer + iov[0].iov_len;
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iov[1].iov_len = exercise - iov[0].iov_len;
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in_csum_iov = in_cksumv(iov, 2);
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if (in_csum_iov != in_csum)
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printf("\nverify: in_cksumv failed, lens: %zu+%zu\n",
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iov[0].iov_len, iov[1].iov_len);
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if (exercise >= 6) {
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/* force split with byte leftover */
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iov[0].iov_base = buffer;
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iov[0].iov_len = (exercise / 2) | 1;
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iov[1].iov_base = buffer + iov[0].iov_len;
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iov[1].iov_len = 2;
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iov[2].iov_base = buffer + iov[0].iov_len + 2;
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iov[2].iov_len = exercise - iov[0].iov_len - 2;
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in_csum_iov = in_cksumv(iov, 3);
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if (in_csum_iov != in_csum)
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printf("\nverify: in_cksumv failed, lens: %zu+%zu+%zu, got %04x, expected %04x\n",
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iov[0].iov_len, iov[1].iov_len,
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iov[2].iov_len, in_csum_iov, in_csum);
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/* force split without byte leftover */
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iov[0].iov_base = buffer;
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iov[0].iov_len = (exercise / 2) & ~1UL;
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iov[1].iov_base = buffer + iov[0].iov_len;
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iov[1].iov_len = 2;
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iov[2].iov_base = buffer + iov[0].iov_len + 2;
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iov[2].iov_len = exercise - iov[0].iov_len - 2;
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in_csum_iov = in_cksumv(iov, 3);
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if (in_csum_iov != in_csum)
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printf("\nverify: in_cksumv failed, lens: %zu+%zu+%zu, got %04x, expected %04x\n",
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iov[0].iov_len, iov[1].iov_len,
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iov[2].iov_len, in_csum_iov, in_csum);
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}
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if (exercise >= FLETCHER_CHECKSUM_VALIDATE)
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continue;
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ospfd = ospfd_checksum(buffer, exercise + sizeof(uint16_t),
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exercise);
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if (verify(buffer, exercise + sizeof(uint16_t)))
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printf("\nverify: ospfd failed\n");
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isisd = iso_csum_create(buffer, exercise + sizeof(uint16_t),
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exercise);
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if (verify(buffer, exercise + sizeof(uint16_t)))
|
|
printf("\nverify: isisd failed\n");
|
|
lib = fletcher_checksum(buffer, exercise + sizeof(uint16_t),
|
|
exercise);
|
|
if (verify(buffer, exercise + sizeof(uint16_t)))
|
|
printf("\nverify: lib failed\n");
|
|
|
|
if (ospfd != lib) {
|
|
printf("\nMismatch in values at size %d\n"
|
|
"ospfd: 0x%04x\tc0: %d\tc1: %d\tx: %d\ty: %d\n"
|
|
"isisd: 0x%04x\tc0: %d\tc1: %d\tx: %d\ty: %d\n"
|
|
"lib: 0x%04x\n",
|
|
exercise, ospfd, ospfd_vals.a.c0,
|
|
ospfd_vals.a.c1, ospfd_vals.x, ospfd_vals.y,
|
|
isisd, isisd_vals.a.c0, isisd_vals.a.c1,
|
|
isisd_vals.x, isisd_vals.y, lib);
|
|
|
|
/* Investigate reduction phase discrepencies */
|
|
if (ospfd_vals.a.c0 == isisd_vals.a.c0
|
|
&& ospfd_vals.a.c1 == isisd_vals.a.c1) {
|
|
printf("\n");
|
|
for (i = 0; reducts[i].name != NULL; i++) {
|
|
ospfd = reducts[i].f(
|
|
&ospfd_vals,
|
|
exercise + sizeof(uint16_t),
|
|
exercise);
|
|
printf("%20s: x: %02x, y %02x, checksum 0x%04x\n",
|
|
reducts[i].name,
|
|
ospfd_vals.x & 0xff,
|
|
ospfd_vals.y & 0xff, ospfd);
|
|
}
|
|
}
|
|
|
|
printf("\n uint8_t testdata [] = {\n ");
|
|
for (i = 0; i < exercise; i++) {
|
|
printf("0x%02x,%s", buffer[i],
|
|
(i + 1) % 8 ? " " : "\n ");
|
|
}
|
|
printf("\n}\n");
|
|
exit(1);
|
|
}
|
|
}
|
|
}
|