| /*- |
| * 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 <tcpdump-stdinc.h> |
| |
| #include "cpack.h" |
| #include "extract.h" |
| |
| u_int8_t * |
| cpack_next_boundary(u_int8_t *buf, u_int8_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. |
| */ |
| u_int8_t * |
| cpack_align_and_reserve(struct cpack_state *cs, size_t wordsize) |
| { |
| u_int8_t *next; |
| |
| /* Ensure alignment. */ |
| next = 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; |
| } |
| |
| int |
| cpack_init(struct cpack_state *cs, u_int8_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 |
| cpack_uint64(struct cpack_state *cs, u_int64_t *u) |
| { |
| u_int8_t *next; |
| |
| if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL) |
| return -1; |
| |
| *u = EXTRACT_LE_64BITS(next); |
| |
| /* Move pointer past the u_int64_t. */ |
| cs->c_next = next + sizeof(*u); |
| return 0; |
| } |
| |
| /* Unpack a 32-bit unsigned integer. */ |
| int |
| cpack_uint32(struct cpack_state *cs, u_int32_t *u) |
| { |
| u_int8_t *next; |
| |
| if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL) |
| return -1; |
| |
| *u = EXTRACT_LE_32BITS(next); |
| |
| /* Move pointer past the u_int32_t. */ |
| cs->c_next = next + sizeof(*u); |
| return 0; |
| } |
| |
| /* Unpack a 16-bit unsigned integer. */ |
| int |
| cpack_uint16(struct cpack_state *cs, u_int16_t *u) |
| { |
| u_int8_t *next; |
| |
| if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL) |
| return -1; |
| |
| *u = EXTRACT_LE_16BITS(next); |
| |
| /* Move pointer past the u_int16_t. */ |
| cs->c_next = next + sizeof(*u); |
| return 0; |
| } |
| |
| /* Unpack an 8-bit unsigned integer. */ |
| int |
| cpack_uint8(struct cpack_state *cs, u_int8_t *u) |
| { |
| /* No space left? */ |
| if ((size_t)(cs->c_next - cs->c_buf) >= cs->c_len) |
| return -1; |
| |
| *u = *cs->c_next; |
| |
| /* Move pointer past the u_int8_t. */ |
| cs->c_next++; |
| return 0; |
| } |