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Diffstat (limited to 'cpack.c')
| -rw-r--r-- | cpack.c | 220 |
1 files changed, 220 insertions, 0 deletions
@@ -0,0 +1,220 @@ +/*- + * Copyright (c) 2003, 2004 David Young. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. 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. + * 3. The name of David Young may not be used to endorse or promote + * products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY DAVID YOUNG ``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 DAVID + * YOUNG 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. + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <stdlib.h> +#include <string.h> +#include "netdissect-stdinc.h" + +#include "netdissect.h" +#include "extract.h" + +#include "cpack.h" + +const uint8_t * +nd_cpack_next_boundary(const uint8_t *buf, const uint8_t *p, size_t alignment) +{ + size_t misalignment = (size_t)(p - buf) % alignment; + + if (misalignment == 0) + return p; + + return p + (alignment - misalignment); +} + +/* Advance to the next wordsize boundary. Return NULL if fewer than + * wordsize bytes remain in the buffer after the boundary. Otherwise, + * return a pointer to the boundary. + */ +const uint8_t * +nd_cpack_align_and_reserve(struct cpack_state *cs, size_t wordsize) +{ + const uint8_t *next; + + /* Ensure alignment. */ + next = nd_cpack_next_boundary(cs->c_buf, cs->c_next, wordsize); + + /* Too little space for wordsize bytes? */ + if (next - cs->c_buf + wordsize > cs->c_len) + return NULL; + + return next; +} + +/* Advance by N bytes without returning them. */ +int +nd_cpack_advance(struct cpack_state *cs, const size_t toskip) +{ + /* No space left? */ + if (cs->c_next - cs->c_buf + toskip > cs->c_len) + return -1; + cs->c_next += toskip; + return 0; +} + +int +nd_cpack_init(struct cpack_state *cs, const uint8_t *buf, size_t buflen) +{ + memset(cs, 0, sizeof(*cs)); + + cs->c_buf = buf; + cs->c_len = buflen; + cs->c_next = cs->c_buf; + + return 0; +} + +/* Unpack a 64-bit unsigned integer. */ +int +nd_cpack_uint64(netdissect_options *ndo, struct cpack_state *cs, uint64_t *u) +{ + const uint8_t *next; + + if ((next = nd_cpack_align_and_reserve(cs, sizeof(*u))) == NULL) + return -1; + + *u = GET_LE_U_8(next); + + /* Move pointer past the uint64_t. */ + cs->c_next = next + sizeof(*u); + return 0; +} + +/* Unpack a 64-bit signed integer. */ +int +nd_cpack_int64(netdissect_options *ndo, struct cpack_state *cs, int64_t *u) +{ + const uint8_t *next; + + if ((next = nd_cpack_align_and_reserve(cs, sizeof(*u))) == NULL) + return -1; + + *u = GET_LE_S_8(next); + + /* Move pointer past the int64_t. */ + cs->c_next = next + sizeof(*u); + return 0; +} + +/* Unpack a 32-bit unsigned integer. */ +int +nd_cpack_uint32(netdissect_options *ndo, struct cpack_state *cs, uint32_t *u) +{ + const uint8_t *next; + + if ((next = nd_cpack_align_and_reserve(cs, sizeof(*u))) == NULL) + return -1; + + *u = GET_LE_U_4(next); + + /* Move pointer past the uint32_t. */ + cs->c_next = next + sizeof(*u); + return 0; +} + +/* Unpack a 32-bit signed integer. */ +int +nd_cpack_int32(netdissect_options *ndo, struct cpack_state *cs, int32_t *u) +{ + const uint8_t *next; + + if ((next = nd_cpack_align_and_reserve(cs, sizeof(*u))) == NULL) + return -1; + + *u = GET_LE_S_4(next); + + /* Move pointer past the int32_t. */ + cs->c_next = next + sizeof(*u); + return 0; +} + +/* Unpack a 16-bit unsigned integer. */ +int +nd_cpack_uint16(netdissect_options *ndo, struct cpack_state *cs, uint16_t *u) +{ + const uint8_t *next; + + if ((next = nd_cpack_align_and_reserve(cs, sizeof(*u))) == NULL) + return -1; + + *u = GET_LE_U_2(next); + + /* Move pointer past the uint16_t. */ + cs->c_next = next + sizeof(*u); + return 0; +} + +/* Unpack a 16-bit signed integer. */ +int +nd_cpack_int16(netdissect_options *ndo, struct cpack_state *cs, int16_t *u) +{ + const uint8_t *next; + + if ((next = nd_cpack_align_and_reserve(cs, sizeof(*u))) == NULL) + return -1; + + *u = GET_LE_S_2(next); + + /* Move pointer past the int16_t. */ + cs->c_next = next + sizeof(*u); + return 0; +} + +/* Unpack an 8-bit unsigned integer. */ +int +nd_cpack_uint8(netdissect_options *ndo, struct cpack_state *cs, uint8_t *u) +{ + /* No space left? */ + if ((size_t)(cs->c_next - cs->c_buf) >= cs->c_len) + return -1; + + *u = GET_U_1(cs->c_next); + + /* Move pointer past the uint8_t. */ + cs->c_next++; + return 0; +} + +/* Unpack an 8-bit signed integer. */ +int +nd_cpack_int8(netdissect_options *ndo, struct cpack_state *cs, int8_t *u) +{ + /* No space left? */ + if ((size_t)(cs->c_next - cs->c_buf) >= cs->c_len) + return -1; + + *u = GET_S_1(cs->c_next); + + /* Move pointer past the int8_t. */ + cs->c_next++; + return 0; +} |