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Diffstat (limited to 'xdr.c')
| -rw-r--r-- | xdr.c | 267 |
1 files changed, 267 insertions, 0 deletions
@@ -0,0 +1,267 @@ +/* + * xdr.c + * ----- + * Serialization/deserialization routines, using XDR (RFC 4506) encoding. + * + * Copyright (c) 2016, NORDUnet A/S All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * - Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * - 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. + * + * - Neither the name of the NORDUnet nor the names of its contributors may + * be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT + * HOLDER 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 <stdio.h> +#include <stdint.h> +#include <string.h> /* memcpy, memset */ + +#ifndef STM32F4XX +#include <arpa/inet.h> /* htonl/ntohl */ +#else +/* htonl is not available in arm-none-eabi headers or libc */ +#ifdef __ARMEL__ /* little endian */ +static inline uint32_t htonl(uint32_t w) +{ + return + ((w & 0x000000ff) << 24) + + ((w & 0x0000ff00) << 8) + + ((w & 0x00ff0000) >> 8) + + ((w & 0xff000000) >> 24); +} +#else +#define htonl(x) (x) +#endif +#define ntohl htonl +#endif + +#include "hal.h" +#include "xdr_internal.h" + +/* encode/decode_int. This covers int, unsigned int, enum, and bool types, + * which are all encoded as 32-bit big-endian fields. Signed integers are + * defined to use two's complement, but that's universal these days, yes? + */ + +hal_error_t hal_xdr_encode_int(uint8_t ** const outbuf, const uint8_t * const limit, const uint32_t value) +{ + /* arg checks */ + if (outbuf == NULL || *outbuf == NULL || limit == NULL) + return HAL_ERROR_BAD_ARGUMENTS; + + /* buffer overflow check */ + if (limit - *outbuf < sizeof(value)) + return HAL_ERROR_IO_BAD_COUNT; + + **(uint32_t **)outbuf = htonl(value); + *outbuf += sizeof(value); + return HAL_OK; +} + +hal_error_t hal_xdr_decode_int(uint8_t **inbuf, const uint8_t * const limit, uint32_t *value) +{ + /* arg checks */ + if (inbuf == NULL || *inbuf == NULL || limit == NULL || value == NULL) + return HAL_ERROR_BAD_ARGUMENTS; + + /* buffer overflow check */ + if (limit - *inbuf < sizeof(*value)) + return HAL_ERROR_IO_BAD_COUNT; + + *value = ntohl(**(uint32_t **)inbuf); + *inbuf += sizeof(*value); + return HAL_OK; +} + +/* encode/decode_buffer. This covers variable-length string and opaque types. + * The data is preceded by a 4-byte length word (encoded as above), and padded + * to a multiple of 4 bytes as necessary. + */ + +hal_error_t hal_xdr_encode_buffer(uint8_t **outbuf, const uint8_t * const limit, const uint8_t *value, const uint32_t len) +{ + hal_error_t ret; + + /* arg checks */ + if (outbuf == NULL || *outbuf == NULL || limit == NULL || + (value == NULL && len != 0)) + return HAL_ERROR_BAD_ARGUMENTS; + + /* buffer overflow check */ + if ((limit - *outbuf) < (((len + 3) & ~3) + sizeof(len))) + return HAL_ERROR_IO_BAD_COUNT; + + /* encode length */ + if ((ret = hal_xdr_encode_int(outbuf, limit, len)) != HAL_OK) + return ret; + + /* write the string or opaque data */ + memcpy(*outbuf, value, len); + *outbuf += len; + + /* pad if necessary */ + if (len & 3) { + size_t n = 4 - (len & 3); + memset(*outbuf, 0, n); + *outbuf += n; + } + + return HAL_OK; +} + +/* This version returns a pointer to the data in the input buffer. + * It is used in the rpc server. + */ +hal_error_t hal_xdr_decode_buffer_in_place(uint8_t **inbuf, const uint8_t * const limit, uint8_t ** const value, uint32_t * const len) +{ + hal_error_t ret; + uint32_t xdr_len; + uint8_t *orig_inbuf = *inbuf; + + /* arg checks */ + if (inbuf == NULL || *inbuf == NULL || limit == NULL || value == NULL || len == NULL) + return HAL_ERROR_BAD_ARGUMENTS; + + /* decode the length */ + if ((ret = hal_xdr_decode_int(inbuf, limit, &xdr_len)) != HAL_OK) + return ret; + + /* input and output buffer overflow checks vs decoded length */ + + /* decoded length is past the end of the input buffer; + * we're probably out of sync, but nothing we can do now + */ + if (limit - *inbuf < xdr_len) { + /* undo read of length */ + *inbuf = orig_inbuf; + return HAL_ERROR_IO_BAD_COUNT; + } + + /* return a pointer to the string or opaque data */ + *value = *inbuf; + *len = xdr_len; + + /* update the buffer pointer, skipping any padding bytes */ + *inbuf += (xdr_len + 3) & ~3; + + return HAL_OK; +} + +/* This version copies the data to the user-supplied buffer. + * It is used in the rpc client. + */ +hal_error_t hal_xdr_decode_buffer(uint8_t **inbuf, const uint8_t * const limit, uint8_t * const value, uint32_t * const len) +{ + hal_error_t ret; + uint8_t *vptr; + uint8_t *orig_inbuf = *inbuf; + uint32_t xdr_len; + + if ((ret = hal_xdr_decode_buffer_in_place(inbuf, limit, &vptr, &xdr_len)) == HAL_OK) { + if (*len < xdr_len) { + /* user buffer is too small, update *len */ + *len = xdr_len; + /* undo read of length */ + *inbuf = orig_inbuf; + return HAL_ERROR_IO_BAD_COUNT; + } + + memcpy(value, vptr, *len); + } + return ret; +} + +/* ---------------------------------------------------------------- */ + +#ifdef TEST +void hexdump(uint8_t *buf, uint32_t len) +{ + int i; + + for (i = 0; i < len; ++i) { + uint8_t c = buf[i]; + printf("%02x ", c); + if ((i & 0x07) == 0x07) + printf("\n"); + } + if ((len & 0x07) != 0) + printf("\n"); +} + +int main(int argc, char *argv[]) +{ + uint32_t i; + uint8_t buf[64] = {0}; + uint8_t *bufptr = buf, *readptr; + uint8_t *limit = buf + sizeof(buf); + hal_error_t ret; + uint8_t alphabet[] = "abcdefghijklmnopqrstuvwxyz"; + uint8_t readbuf[64] = {0}; + + printf("hal_xdr_encode_int: work to failure\n"); + for (i = 1; i < 100; ++i) { + if ((ret = hal_xdr_encode_int(&bufptr, limit, i)) != HAL_OK) { + printf("%d: %s\n", i, hal_error_string(ret)); + break; + } + } + hexdump(buf, ((uint8_t *)bufptr - buf)); + + printf("\nhal_xdr_decode_int:\n"); + readptr = buf; + while (readptr < bufptr) { + if ((ret = hal_xdr_decode_int(&readptr, limit, &i)) != HAL_OK) { + printf("%s\n", hal_error_string(ret)); + break; + } + printf("%u ", i); + } + printf("\n"); + + printf("\nhal_xdr_encode_buffer: work to failure\n"); + memset(buf, 0, sizeof(buf)); + bufptr = buf; + for (i = 1; i < 10; ++i) { + if ((ret = hal_xdr_encode_buffer(&bufptr, limit, alphabet, i)) != HAL_OK) { + printf("%d: %s\n", i, hal_error_string(ret)); + break; + } + } + hexdump(buf, ((uint8_t *)bufptr - buf)); + + printf("\nhal_xdr_decode_buffer:\n"); + readptr = buf; + i = sizeof(readbuf); + while (readptr < bufptr) { + if ((ret = hal_xdr_decode_buffer(&readptr, limit, readbuf, &i)) != HAL_OK) { + printf("%s\n", hal_error_string(ret)); + break; + } + printf("%u: ", i); for (int j = 0; j < i; ++j) putchar(readbuf[j]); putchar('\n'); + i = sizeof(readbuf); + memset(readbuf, 0, sizeof(readbuf)); + } + + return 0; +} +#endif |