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/*
* Copyright (c) 2009 Nicira Networks.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "csum.h"
#include <inttypes.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "random.h"
#include "util.h"
#undef NDEBUG
#include <assert.h>
struct test_case {
char *data;
size_t size;
uint16_t csum;
};
#define TEST_CASE(DATA, CSUM) { DATA, (sizeof DATA) - 1, CSUM }
static const struct test_case test_cases[] = {
/* RFC 1071 section 3. */
TEST_CASE("\x00\x01\xf2\x03\xf4\xf5\xf6\xf7", (uint16_t) ~0xddf2),
/* http://www.sbprojects.com/projects/tcpip/theory/theory14.htm */
TEST_CASE("\x45\x00\x00\x28\x1F\xFD\x40\x00\x80\x06"
"\x00\x00\xC0\xA8\x3B\x0A\xC0\xA8\x3B\x32",
0xe345),
/* http://mathforum.org/library/drmath/view/54379.html */
TEST_CASE("\x86\x5e\xac\x60\x71\x2a\x81\xb5", 0xda60),
};
static void
mark(char c)
{
putchar(c);
fflush(stdout);
}
#if 0
/* This code is useful for generating new test cases for RFC 1624 section 4. */
static void
generate_rfc1624_test_case(void)
{
int i;
for (i = 0; i < 10000000; i++) {
uint32_t data[8];
int j;
for (j = 0; j < 8; j++) {
data[j] = random_uint32();
}
data[7] &= 0x0000ffff;
data[7] |= 0x55550000;
if (ntohs(~csum(data, sizeof data - 2)) == 0xcd7a) {
ovs_hex_dump(stdout, data, sizeof data, 0, false);
exit(0);
}
}
}
#endif
/* Make sure we get the calculation in RFC 1624 section 4 correct. */
static void
test_rfc1624(void)
{
/* "...an IP packet header in which a 16-bit field m = 0x5555..." */
uint8_t data[32] =
"\xfe\x8f\xc1\x14\x4b\x6f\x70\x2a\x80\x29\x78\xc0\x58\x81\x77\xaa"
"\x66\x64\xfc\x96\x63\x97\x64\xee\x12\x53\x1d\xa9\x2d\xa9\x55\x55";
/* "...the one's complement sum of all other header octets is 0xCD7A." */
assert(ntohs(csum(data, sizeof data - 2)) == (uint16_t) ~0xcd7a);
/* "...the header checksum would be:
HC = ~(0xCD7A + 0x5555)
= ~0x22D0
= 0xDD2F"
*/
assert(ntohs(csum(data, sizeof data)) == 0xdd2f);
/* "a 16-bit field m = 0x5555 changes to m' = 0x3285..." */
data[30] = 0x32;
data[31] = 0x85;
/* "The new checksum via recomputation is:
HC' = ~(0xCD7A + 0x3285)
= ~0xFFFF
= 0x0000"
*/
assert(ntohs(csum(data, sizeof data)) == 0x0000);
/* "Applying [Eqn. 3] to the example above, we get the correct result:
HC' = ~(C + (-m) + m')
= ~(0x22D0 + ~0x5555 + 0x3285)
= ~0xFFFF
= 0x0000" */
assert(recalc_csum16(0xdd2f, 0x5555, 0x3285) == 0x0000);
mark('#');
}
int
main(void)
{
const struct test_case *tc;
int i;
for (tc = test_cases; tc < &test_cases[ARRAY_SIZE(test_cases)]; tc++) {
const uint16_t *data16 = (const uint16_t *) tc->data;
const uint32_t *data32 = (const uint32_t *) tc->data;
uint32_t partial;
size_t i;
/* Test csum(). */
assert(ntohs(csum(tc->data, tc->size)) == tc->csum);
mark('.');
/* Test csum_add16(). */
partial = 0;
for (i = 0; i < tc->size / 2; i++) {
partial = csum_add16(partial, data16[i]);
}
assert(ntohs(csum_finish(partial)) == tc->csum);
mark('.');
/* Test csum_add32(). */
partial = 0;
for (i = 0; i < tc->size / 4; i++) {
partial = csum_add32(partial, data32[i]);
}
assert(ntohs(csum_finish(partial)) == tc->csum);
mark('.');
/* Test alternating csum_add16() and csum_add32(). */
partial = 0;
for (i = 0; i < tc->size / 4; i++) {
if (i % 2) {
partial = csum_add32(partial, data32[i]);
} else {
partial = csum_add16(partial, data16[i * 2]);
partial = csum_add16(partial, data16[i * 2 + 1]);
}
}
assert(ntohs(csum_finish(partial)) == tc->csum);
mark('.');
/* Test csum_continue(). */
partial = 0;
for (i = 0; i < tc->size / 4; i++) {
if (i) {
partial = csum_continue(partial, &data32[i], 4);
} else {
partial = csum_continue(partial, &data16[i * 2], 2);
partial = csum_continue(partial, &data16[i * 2 + 1], 2);
}
}
assert(ntohs(csum_finish(partial)) == tc->csum);
mark('#');
}
test_rfc1624();
/* Test recalc_csum16(). */
for (i = 0; i < 32; i++) {
uint16_t old_u16, new_u16;
uint16_t old_csum;
uint16_t data[16];
int j, index;
for (j = 0; j < ARRAY_SIZE(data); j++) {
data[j] = random_uint32();
}
old_csum = csum(data, sizeof data);
index = random_range(ARRAY_SIZE(data));
old_u16 = data[index];
new_u16 = data[index] = random_uint32();
assert(csum(data, sizeof data)
== recalc_csum16(old_csum, old_u16, new_u16));
mark('.');
}
mark('#');
/* Test recalc_csum32(). */
for (i = 0; i < 32; i++) {
uint32_t old_u32, new_u32;
uint16_t old_csum;
uint32_t data[16];
int j, index;
for (j = 0; j < ARRAY_SIZE(data); j++) {
data[j] = random_uint32();
}
old_csum = csum(data, sizeof data);
index = random_range(ARRAY_SIZE(data));
old_u32 = data[index];
new_u32 = data[index] = random_uint32();
assert(csum(data, sizeof data)
== recalc_csum32(old_csum, old_u32, new_u32));
mark('.');
}
mark('#');
putchar('\n');
return 0;
}
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