Harald Welte | b9ce51c | 2010-06-30 19:43:11 +0200 | [diff] [blame] | 1 | /* GPRS LLC cipher core infrastructure */ |
| 2 | |
| 3 | /* (C) 2010 by Harald Welte <laforge@gnumonks.org> |
| 4 | * |
| 5 | * All Rights Reserved |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License along |
| 18 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 19 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #include <errno.h> |
| 24 | #include <stdint.h> |
| 25 | |
| 26 | #include <osmocore/utils.h> |
| 27 | #include <osmocore/linuxlist.h> |
| 28 | #include <osmocore/plugin.h> |
| 29 | |
| 30 | #include <osmocom/crypt/gprs_cipher.h> |
| 31 | |
| 32 | static LLIST_HEAD(gprs_ciphers); |
| 33 | |
| 34 | static struct gprs_cipher_impl *selected_ciphers[_GPRS_ALGO_NUM]; |
| 35 | |
| 36 | /* register a cipher with the core */ |
| 37 | int gprs_cipher_register(struct gprs_cipher_impl *ciph) |
| 38 | { |
| 39 | if (ciph->algo > ARRAY_SIZE(selected_ciphers)) |
| 40 | return -ERANGE; |
| 41 | |
| 42 | llist_add_tail(&ciph->list, &gprs_ciphers); |
| 43 | |
| 44 | /* check if we want to select this implementation over others */ |
| 45 | if (!selected_ciphers[ciph->algo] || |
| 46 | (selected_ciphers[ciph->algo]->priority > ciph->priority)) |
| 47 | selected_ciphers[ciph->algo] = ciph; |
| 48 | |
| 49 | return 0; |
| 50 | } |
| 51 | |
| 52 | /* load all available GPRS cipher plugins */ |
| 53 | int gprs_cipher_load(const char *path) |
| 54 | { |
| 55 | /* load all plugins available from path */ |
| 56 | return plugin_load_all(path); |
| 57 | } |
| 58 | |
| 59 | /* function to be called by core code */ |
| 60 | int gprs_cipher_run(uint8_t *out, uint16_t len, enum gprs_ciph_algo algo, |
| 61 | uint64_t kc, uint32_t iv, enum gprs_cipher_direction dir) |
| 62 | { |
| 63 | if (algo > ARRAY_SIZE(selected_ciphers)) |
| 64 | return -ERANGE; |
| 65 | |
| 66 | if (!selected_ciphers[algo]) |
| 67 | return -EINVAL; |
| 68 | |
| 69 | if (len > GSM0464_CIPH_MAX_BLOCK) |
| 70 | return -ERANGE; |
| 71 | |
| 72 | /* run the actual cipher from the plugin */ |
| 73 | return selected_ciphers[algo]->run(out, len, kc, iv, dir); |
| 74 | } |
| 75 | |
| 76 | int gprs_cipher_supported(enum gprs_ciph_algo algo) |
| 77 | { |
| 78 | if (algo > ARRAY_SIZE(selected_ciphers)) |
| 79 | return -ERANGE; |
| 80 | |
| 81 | if (selected_ciphers[algo]) |
| 82 | return 1; |
| 83 | |
| 84 | return 0; |
| 85 | } |
Harald Welte | e335b91 | 2010-06-30 19:50:14 +0200 | [diff] [blame] | 86 | |
| 87 | /* GSM TS 04.64 / Section A.2.1 : Generation of 'input' */ |
| 88 | uint32_t gprs_cipher_gen_input_ui(uint32_t iov_ui, uint8_t sapi, uint32_t lfn, uint32_t oc) |
| 89 | { |
| 90 | uint32_t sx = ((1<<27) * sapi) + (1<<31); |
| 91 | |
| 92 | return (iov_ui ^ sx) + lfn + oc; |
| 93 | } |
| 94 | |
| 95 | /* GSM TS 04.64 / Section A.2.1 : Generation of 'input' */ |
| 96 | uint32_t gprs_cipher_gen_input_i(uint32_t iov_i, uint32_t lfn, uint32_t oc) |
| 97 | { |
| 98 | return iov_i + lfn + oc; |
| 99 | } |