/*
* rpc_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 */
#include <strings.h> /* bzero */
#include <arpa/inet.h> /* htonl/ntohl */
#include "hal.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 rpc_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 rpc_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 rpc_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 = rpc_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);
bzero(*outbuf, 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 rpc_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 = rpc_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;
}
/* user buffer is too small, update *len
*/
if (*len < xdr_len) {
*len = 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 rpc_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;
if ((ret = rpc_decode_buffer_in_place(inbuf, limit, &vptr, len)) == HAL_OK)
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("rpc_encode_int: work to failure\n");
for (i = 1; i < 100; ++i) {
if ((ret = rpc_encode_int(&bufptr, limit, i)) != HAL_OK) {
printf("%d: %s\n", i, hal_error_string(ret));
break;
}
}
hexdump(buf, ((uint8_t *)bufptr - buf));
printf("\nrpc_decode_int:\n");
readptr = buf;
while (readptr < bufptr) {
if ((ret = rpc_decode_int(&readptr, limit, &i)) != HAL_OK) {
printf("%s\n", hal_error_string(ret));
break;
}
printf("%u ", i);
}
printf("\n");
printf("\nrpc_encode_buffer: work to failure\n");
bzero(buf, sizeof(buf));
bufptr = buf;
for (i = 1; i < 10; ++i) {
if ((ret = rpc_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("\nrpc_decode_buffer:\n");
readptr = buf;
i = sizeof(readbuf);
while (readptr < bufptr) {
if ((ret = rpc_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);
bzero(readbuf, sizeof(readbuf));
}
return 0;
}
#endif
