/* * Copyright (c) 2015 Cisco and/or its affiliates. * 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. */ /* * ip4/ip_checksum.c: ip/tcp/udp checksums * * Copyright (c) 2008 Eliot Dresselhaus * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #include <vnet/ip/ip.h> static ip_csum_t _ip_incremental_checksum (ip_csum_t sum, void *_data, uword n_bytes) { uword data = pointer_to_uword (_data); ip_csum_t sum0, sum1; sum0 = 0; sum1 = sum; /* * Align pointer to 64 bits. The ip checksum is a 16-bit * one's complememt sum. It's impractical to optimize * the calculation if the incoming address is odd. */ #define _(t) \ do { \ if (n_bytes >= sizeof (t) \ && sizeof (t) < sizeof (ip_csum_t) \ && (data % (2 * sizeof (t))) != 0) \ { \ sum0 += * uword_to_pointer (data, t *); \ data += sizeof (t); \ n_bytes -= sizeof (t); \ } \ } while (0) if (PREDICT_TRUE ((data & 1) == 0)) { _(u16); if (BITS (ip_csum_t) > 32) _(u32); } #undef _ { ip_csum_t *d = uword_to_pointer (data, ip_csum_t *); while (n_bytes >= 2 * sizeof (d[0])) { sum0 = ip_csum_with_carry (sum0, d[0]); sum1 = ip_csum_with_carry (sum1, d[1]); d += 2; n_bytes -= 2 * sizeof (d[0]); } data = pointer_to_uword (d); } #define _(t) \ do { \ if (n_bytes >= sizeof (t) && sizeof (t) <= sizeof (ip_csum_t)) \ { \ sum0 = ip_csum_with_carry (sum0, * uword_to_pointer (data, t *)); \ data += sizeof (t); \ n_bytes -= sizeof (t); \ } \ } while (0) if (BITS (ip_csum_t) > 32) _(u64); _(u32); _(u16); _(u8); #undef _ /* Combine even and odd sums. */ sum0 = ip_csum_with_carry (sum0, sum1); return sum0; } /* * Note: the tcp / udp checksum calculation is performance critical * [e.g. when NIC h/w offload is not available], * so it's worth producing architecture-dependent code. * * ip_incremental_checksum() is an always-inlined static * function which uses the function pointer we set up in * ip_checksum_init(). */ ip_csum_t (*vnet_incremental_checksum_fp) (ip_csum_t, void *, uword); clib_error_t * ip_checksum_init (vlib_main_t *vm) { vnet_incremental_checksum_fp = _ip_incremental_checksum; return 0; } VLIB_INIT_FUNCTION (ip_checksum_init); #if CLIB_DEBUG > 0 static const char test_pkt[] = { 0x45, 0x00, 0x00, 0x3c, 0x5d, 0x6f, 0x40, 0x00, 0x40, 0x06, 0x3f, 0x6b, 0x0a, 0x76, 0x72, 0x44, 0x0a, 0x56, 0x16, 0xd2, }; static clib_error_t * test_ip_checksum_fn (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd) { u16 csum; ip4_header_t *hp; u8 *align_test = 0; int offset; vec_validate (align_test, ARRAY_LEN (test_pkt) + 7); for (offset = 0; offset < 8; offset++) { memcpy (align_test + offset, test_pkt, ARRAY_LEN (test_pkt)); hp = (ip4_header_t *) (align_test + offset); csum = ip4_header_checksum (hp); vlib_cli_output (vm, "offset %d checksum %u expected result 27455", offset, (u32) csum); } return 0; } /* *INDENT-OFF* */ VLIB_CLI_COMMAND (test_checksum, static) = { .path = "test ip checksum", .short_help = "test ip checksum", .function = test_ip_checksum_fn, }; /* *INDENT-ON* */ #endif /* CLIB_DEBUG */ /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */