The Android Open Source Project | 2949f58 | 2009-03-03 19:30:46 -0800 | [diff] [blame] | 1 | /*- |
| 2 | * Copyright (c) 2003, 2004 David Young. All rights reserved. |
| 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * 1. Redistributions of source code must retain the above copyright |
| 8 | * notice, this list of conditions and the following disclaimer. |
| 9 | * 2. Redistributions in binary form must reproduce the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer in the |
| 11 | * documentation and/or other materials provided with the distribution. |
| 12 | * 3. The name of David Young may not be used to endorse or promote |
| 13 | * products derived from this software without specific prior |
| 14 | * written permission. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY DAVID YOUNG ``AS IS'' AND ANY |
| 17 | * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
| 18 | * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
| 19 | * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DAVID |
| 20 | * YOUNG BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 21 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED |
| 22 | * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| 24 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| 25 | * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY |
| 27 | * OF SUCH DAMAGE. |
| 28 | */ |
| 29 | |
| 30 | #ifdef HAVE_CONFIG_H |
| 31 | #include "config.h" |
| 32 | #endif |
| 33 | |
| 34 | #include <stdlib.h> |
| 35 | #include <string.h> |
| 36 | #include <tcpdump-stdinc.h> |
| 37 | |
| 38 | #include "cpack.h" |
| 39 | #include "extract.h" |
| 40 | |
JP Abgrall | 53f17a9 | 2014-02-12 14:02:41 -0800 | [diff] [blame] | 41 | u_int8_t * |
The Android Open Source Project | 2949f58 | 2009-03-03 19:30:46 -0800 | [diff] [blame] | 42 | cpack_next_boundary(u_int8_t *buf, u_int8_t *p, size_t alignment) |
| 43 | { |
| 44 | size_t misalignment = (size_t)(p - buf) % alignment; |
| 45 | |
| 46 | if (misalignment == 0) |
| 47 | return p; |
| 48 | |
| 49 | return p + (alignment - misalignment); |
| 50 | } |
| 51 | |
| 52 | /* Advance to the next wordsize boundary. Return NULL if fewer than |
| 53 | * wordsize bytes remain in the buffer after the boundary. Otherwise, |
| 54 | * return a pointer to the boundary. |
| 55 | */ |
JP Abgrall | 53f17a9 | 2014-02-12 14:02:41 -0800 | [diff] [blame] | 56 | u_int8_t * |
The Android Open Source Project | 2949f58 | 2009-03-03 19:30:46 -0800 | [diff] [blame] | 57 | cpack_align_and_reserve(struct cpack_state *cs, size_t wordsize) |
| 58 | { |
| 59 | u_int8_t *next; |
| 60 | |
| 61 | /* Ensure alignment. */ |
| 62 | next = cpack_next_boundary(cs->c_buf, cs->c_next, wordsize); |
| 63 | |
| 64 | /* Too little space for wordsize bytes? */ |
| 65 | if (next - cs->c_buf + wordsize > cs->c_len) |
| 66 | return NULL; |
| 67 | |
| 68 | return next; |
| 69 | } |
| 70 | |
JP Abgrall | 53f17a9 | 2014-02-12 14:02:41 -0800 | [diff] [blame] | 71 | /* Advance by N bytes without returning them. */ |
| 72 | int |
| 73 | cpack_advance(struct cpack_state *cs, const size_t toskip) |
| 74 | { |
| 75 | /* No space left? */ |
| 76 | if (cs->c_next - cs->c_buf + toskip > cs->c_len) |
| 77 | return -1; |
| 78 | cs->c_next += toskip; |
| 79 | return 0; |
| 80 | } |
| 81 | |
The Android Open Source Project | 2949f58 | 2009-03-03 19:30:46 -0800 | [diff] [blame] | 82 | int |
| 83 | cpack_init(struct cpack_state *cs, u_int8_t *buf, size_t buflen) |
| 84 | { |
| 85 | memset(cs, 0, sizeof(*cs)); |
| 86 | |
| 87 | cs->c_buf = buf; |
| 88 | cs->c_len = buflen; |
| 89 | cs->c_next = cs->c_buf; |
| 90 | |
| 91 | return 0; |
| 92 | } |
| 93 | |
| 94 | /* Unpack a 64-bit unsigned integer. */ |
| 95 | int |
| 96 | cpack_uint64(struct cpack_state *cs, u_int64_t *u) |
| 97 | { |
| 98 | u_int8_t *next; |
| 99 | |
| 100 | if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL) |
| 101 | return -1; |
| 102 | |
| 103 | *u = EXTRACT_LE_64BITS(next); |
| 104 | |
| 105 | /* Move pointer past the u_int64_t. */ |
| 106 | cs->c_next = next + sizeof(*u); |
| 107 | return 0; |
| 108 | } |
| 109 | |
| 110 | /* Unpack a 32-bit unsigned integer. */ |
| 111 | int |
| 112 | cpack_uint32(struct cpack_state *cs, u_int32_t *u) |
| 113 | { |
| 114 | u_int8_t *next; |
| 115 | |
| 116 | if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL) |
| 117 | return -1; |
| 118 | |
| 119 | *u = EXTRACT_LE_32BITS(next); |
| 120 | |
| 121 | /* Move pointer past the u_int32_t. */ |
| 122 | cs->c_next = next + sizeof(*u); |
| 123 | return 0; |
| 124 | } |
| 125 | |
| 126 | /* Unpack a 16-bit unsigned integer. */ |
| 127 | int |
| 128 | cpack_uint16(struct cpack_state *cs, u_int16_t *u) |
| 129 | { |
| 130 | u_int8_t *next; |
| 131 | |
| 132 | if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL) |
| 133 | return -1; |
| 134 | |
| 135 | *u = EXTRACT_LE_16BITS(next); |
| 136 | |
| 137 | /* Move pointer past the u_int16_t. */ |
| 138 | cs->c_next = next + sizeof(*u); |
| 139 | return 0; |
| 140 | } |
| 141 | |
| 142 | /* Unpack an 8-bit unsigned integer. */ |
| 143 | int |
| 144 | cpack_uint8(struct cpack_state *cs, u_int8_t *u) |
| 145 | { |
| 146 | /* No space left? */ |
| 147 | if ((size_t)(cs->c_next - cs->c_buf) >= cs->c_len) |
| 148 | return -1; |
| 149 | |
| 150 | *u = *cs->c_next; |
| 151 | |
| 152 | /* Move pointer past the u_int8_t. */ |
| 153 | cs->c_next++; |
| 154 | return 0; |
| 155 | } |