Adding chunk_mac() which calculates a 64-bit MAC using SipHash-2-4
[strongswan.git] / src / libstrongswan / utils / chunk.h
1 /*
2 * Copyright (C) 2008-2013 Tobias Brunner
3 * Copyright (C) 2005-2008 Martin Willi
4 * Copyright (C) 2005 Jan Hutter
5 * Hochschule fuer Technik Rapperswil
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * for more details.
16 */
17
18 /**
19 * @defgroup chunk chunk
20 * @{ @ingroup utils
21 */
22
23 #ifndef CHUNK_H_
24 #define CHUNK_H_
25
26 #include <string.h>
27 #include <stdarg.h>
28 #include <sys/types.h>
29 #ifdef HAVE_ALLOCA_H
30 #include <alloca.h>
31 #endif
32
33 typedef struct chunk_t chunk_t;
34
35 /**
36 * General purpose pointer/length abstraction.
37 */
38 struct chunk_t {
39 /** Pointer to start of data */
40 u_char *ptr;
41 /** Length of data in bytes */
42 size_t len;
43 };
44
45 #include "utils.h"
46
47 /**
48 * A { NULL, 0 }-chunk handy for initialization.
49 */
50 extern chunk_t chunk_empty;
51
52 /**
53 * Create a new chunk pointing to "ptr" with length "len"
54 */
55 static inline chunk_t chunk_create(u_char *ptr, size_t len)
56 {
57 chunk_t chunk = {ptr, len};
58 return chunk;
59 }
60
61 /**
62 * Create a clone of a chunk pointing to "ptr"
63 */
64 chunk_t chunk_create_clone(u_char *ptr, chunk_t chunk);
65
66 /**
67 * Calculate length of multiple chunks
68 */
69 size_t chunk_length(const char *mode, ...);
70
71 /**
72 * Concatenate chunks into a chunk pointing to "ptr".
73 *
74 * The mode string specifies the number of chunks, and how to handle each of
75 * them with a single character: 'c' for copy (allocate new chunk), 'm' for move
76 * (free given chunk) or 's' for sensitive-move (clear given chunk, then free).
77 */
78 chunk_t chunk_create_cat(u_char *ptr, const char* mode, ...);
79
80 /**
81 * Split up a chunk into parts, "mode" is a string of "a" (alloc),
82 * "c" (copy) and "m" (move). Each letter say for the corresponding chunk if
83 * it should get allocated on heap, copied into existing chunk, or the chunk
84 * should point into "chunk". The length of each part is an argument before
85 * each target chunk. E.g.:
86 * chunk_split(chunk, "mcac", 3, &a, 7, &b, 5, &c, d.len, &d);
87 */
88 void chunk_split(chunk_t chunk, const char *mode, ...);
89
90 /**
91 * Write the binary contents of a chunk_t to a file
92 *
93 * @param chunk contents to write to file
94 * @param path path where file is written to
95 * @param label label specifying file type
96 * @param mask file mode creation mask
97 * @param force overwrite existing file by force
98 * @return TRUE if write operation was successful
99 */
100 bool chunk_write(chunk_t chunk, char *path, char *label, mode_t mask, bool force);
101
102 /**
103 * Convert a chunk of data to hex encoding.
104 *
105 * The resulting string is '\\0' terminated, but the chunk does not include
106 * the '\\0'. If buf is supplied, it must hold at least (chunk.len * 2 + 1).
107 *
108 * @param chunk data to convert to hex encoding
109 * @param buf buffer to write to, NULL to malloc
110 * @param uppercase TRUE to use uppercase letters
111 * @return chunk of encoded data
112 */
113 chunk_t chunk_to_hex(chunk_t chunk, char *buf, bool uppercase);
114
115 /**
116 * Convert a hex encoded in a binary chunk.
117 *
118 * If buf is supplied, it must hold at least (hex.len / 2) + (hex.len % 2)
119 * bytes. It is filled by the right to give correct values for short inputs.
120 *
121 * @param hex hex encoded input data
122 * @param buf buffer to write decoded data, NULL to malloc
123 * @return converted data
124 */
125 chunk_t chunk_from_hex(chunk_t hex, char *buf);
126
127 /**
128 * Convert a chunk of data to its base64 encoding.
129 *
130 * The resulting string is '\\0' terminated, but the chunk does not include
131 * the '\\0'. If buf is supplied, it must hold at least (chunk.len * 4 / 3 + 1).
132 *
133 * @param chunk data to convert
134 * @param buf buffer to write to, NULL to malloc
135 * @return chunk of encoded data
136 */
137 chunk_t chunk_to_base64(chunk_t chunk, char *buf);
138
139 /**
140 * Convert a base64 in a binary chunk.
141 *
142 * If buf is supplied, it must hold at least (base64.len / 4 * 3).
143 *
144 * @param base64 base64 encoded input data
145 * @param buf buffer to write decoded data, NULL to malloc
146 * @return converted data
147 */
148 chunk_t chunk_from_base64(chunk_t base64, char *buf);
149
150 /**
151 * Convert a chunk of data to its base32 encoding.
152 *
153 * The resulting string is '\\0' terminated, but the chunk does not include
154 * the '\\0'. If buf is supplied, it must hold (chunk.len * 8 / 5 + 1) bytes.
155 *
156 * @param chunk data to convert
157 * @param buf buffer to write to, NULL to malloc
158 * @return chunk of encoded data
159 */
160 chunk_t chunk_to_base32(chunk_t chunk, char *buf);
161
162 /**
163 * Free contents of a chunk
164 */
165 static inline void chunk_free(chunk_t *chunk)
166 {
167 free(chunk->ptr);
168 *chunk = chunk_empty;
169 }
170
171 /**
172 * Overwrite the contents of a chunk and free it
173 */
174 static inline void chunk_clear(chunk_t *chunk)
175 {
176 if (chunk->ptr)
177 {
178 memwipe(chunk->ptr, chunk->len);
179 chunk_free(chunk);
180 }
181 }
182
183 /**
184 * Initialize a chunk using a char array
185 */
186 #define chunk_from_chars(...) ((chunk_t){(char[]){__VA_ARGS__}, sizeof((char[]){__VA_ARGS__})})
187
188 /**
189 * Initialize a chunk to point to a thing
190 */
191 #define chunk_from_thing(thing) chunk_create((char*)&(thing), sizeof(thing))
192
193 /**
194 * Initialize a chunk from a static string, not containing 0-terminator
195 */
196 #define chunk_from_str(str) chunk_create(str, strlen(str))
197
198 /**
199 * Allocate a chunk on the heap
200 */
201 #define chunk_alloc(bytes) ({size_t x = (bytes); chunk_create(x ? malloc(x) : NULL, x);})
202
203 /**
204 * Allocate a chunk on the stack
205 */
206 #define chunk_alloca(bytes) ({size_t x = (bytes); chunk_create(x ? alloca(x) : NULL, x);})
207
208 /**
209 * Clone a chunk on heap
210 */
211 #define chunk_clone(chunk) ({chunk_t x = (chunk); chunk_create_clone(x.len ? malloc(x.len) : NULL, x);})
212
213 /**
214 * Clone a chunk on stack
215 */
216 #define chunk_clonea(chunk) ({chunk_t x = (chunk); chunk_create_clone(x.len ? alloca(x.len) : NULL, x);})
217
218 /**
219 * Concatenate chunks into a chunk on heap
220 */
221 #define chunk_cat(mode, ...) chunk_create_cat(malloc(chunk_length(mode, __VA_ARGS__)), mode, __VA_ARGS__)
222
223 /**
224 * Concatenate chunks into a chunk on stack
225 */
226 #define chunk_cata(mode, ...) chunk_create_cat(alloca(chunk_length(mode, __VA_ARGS__)), mode, __VA_ARGS__)
227
228 /**
229 * Skip n bytes in chunk (forward pointer, shorten length)
230 */
231 static inline chunk_t chunk_skip(chunk_t chunk, size_t bytes)
232 {
233 if (chunk.len > bytes)
234 {
235 chunk.ptr += bytes;
236 chunk.len -= bytes;
237 return chunk;
238 }
239 return chunk_empty;
240 }
241
242 /**
243 * Skip a leading zero-valued byte
244 */
245 static inline chunk_t chunk_skip_zero(chunk_t chunk)
246 {
247 if (chunk.len > 1 && *chunk.ptr == 0x00)
248 {
249 chunk.ptr++;
250 chunk.len--;
251 }
252 return chunk;
253 }
254
255
256 /**
257 * Compare two chunks, returns zero if a equals b
258 * or negative/positive if a is small/greater than b
259 */
260 int chunk_compare(chunk_t a, chunk_t b);
261
262 /**
263 * Compare two chunks for equality,
264 * NULL chunks are never equal.
265 */
266 static inline bool chunk_equals(chunk_t a, chunk_t b)
267 {
268 return a.ptr != NULL && b.ptr != NULL &&
269 a.len == b.len && memeq(a.ptr, b.ptr, a.len);
270 }
271
272 /**
273 * Compare two chunks (given as pointers) for equality (useful as callback),
274 * NULL chunks are never equal.
275 */
276 static inline bool chunk_equals_ptr(chunk_t *a, chunk_t *b)
277 {
278 return a != NULL && b != NULL && chunk_equals(*a, *b);
279 }
280
281 /**
282 * Increment a chunk, as it would reprensent a network order integer.
283 *
284 * @param chunk chunk to increment
285 * @return TRUE if an overflow occurred
286 */
287 bool chunk_increment(chunk_t chunk);
288
289 /**
290 * Check if a chunk has printable characters only.
291 *
292 * If sane is given, chunk is cloned into sane and all non printable characters
293 * get replaced by "replace".
294 *
295 * @param chunk chunk to check for printability
296 * @param sane pointer where sane version is allocated, or NULL
297 * @param replace character to use for replaceing unprintable characters
298 * @return TRUE if all characters in chunk are printable
299 */
300 bool chunk_printable(chunk_t chunk, chunk_t *sane, char replace);
301
302 /**
303 * Computes a 32 bit hash of the given chunk.
304 * @note This hash is only intended for hash tables not for cryptographic purposes.
305 */
306 u_int32_t chunk_hash(chunk_t chunk);
307
308 /**
309 * Incremental version of chunk_hash. Use this to hash two or more chunks.
310 */
311 u_int32_t chunk_hash_inc(chunk_t chunk, u_int32_t hash);
312
313 /**
314 * Computes a quick MAC from the given chunk and key using SipHash.
315 *
316 * The key must have a length of 128-bit (16 bytes).
317 *
318 * @note While SipHash has strong features using it for cryptographic purposes
319 * is not recommended (in particular because of the rather short output size).
320 *
321 * @param chunk data to process
322 * @param key key to use
323 * @return MAC for given input and key
324 */
325 u_int64_t chunk_mac(chunk_t chunk, u_char *key);
326
327 /**
328 * printf hook function for chunk_t.
329 *
330 * Arguments are:
331 * chunk_t *chunk
332 * Use #-modifier to print a compact version
333 */
334 int chunk_printf_hook(printf_hook_data_t *data, printf_hook_spec_t *spec,
335 const void *const *args);
336
337 #endif /** CHUNK_H_ @}*/