/* * Copyright (c) 2009, 2010 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 #include "csum.h" #include #include #include #include #include #include "random.h" #include "unaligned.h" #include "util.h" #undef NDEBUG #include struct test_case { char *data; size_t size; /* Test requires a multiple of 4. */ 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; /* 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, get_unaligned_u16(&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, get_unaligned_u32(&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, get_unaligned_u32(&data32[i])); } else { uint16_t u0 = get_unaligned_u16(&data16[i * 2]); uint16_t u1 = get_unaligned_u16(&data16[i * 2 + 1]); partial = csum_add16(partial, u0); partial = csum_add16(partial, u1); } } 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; }