libosmogsm  0.11.0-dirty
Osmocom GSM library
include/osmocom/crypt/gprs_cipher.h
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00001 
00003 #pragma once
00004 
00005 #include <osmocom/core/linuxlist.h>
00006 #include <osmocom/core/utils.h>
00007 
00008 #include <stdint.h>
00009 
00010 #define GSM0464_CIPH_MAX_BLOCK  1523
00011 
00012 /* 3GPP TS 24.008 ยง 10.5.5.3 */
00013 enum gprs_ciph_algo {
00014         GPRS_ALGO_GEA0 = 0,
00015         GPRS_ALGO_GEA1 = 1,
00016         GPRS_ALGO_GEA2 = 2,
00017         GPRS_ALGO_GEA3 = 3,
00018         GPRS_ALGO_GEA4 = 4,
00019         _GPRS_ALGO_NUM
00020 };
00021 
00022 /* 3GPP TS 04.64 Table A.1: */
00023 enum gprs_cipher_direction {
00024         GPRS_CIPH_MS2SGSN = 0,
00025         GPRS_CIPH_SGSN2MS = 1,
00026 };
00027 
00028 extern const struct value_string gprs_cipher_names[];
00029 
00030 /* An implementation of a GPRS cipher */
00031 struct gprs_cipher_impl {
00032         struct llist_head list;
00033         enum gprs_ciph_algo algo;
00034         const char *name;
00035         unsigned int priority;
00036 
00037         /* As specified in 04.64 Annex A.  Uses Kc, IV and direction
00038          * to generate the 1523 bytes cipher stream that need to be
00039          * XORed wit the plaintext for encrypt / ciphertext for decrypt */
00040         int (*run)(uint8_t *out, uint16_t len, uint8_t *kc, uint32_t iv,
00041                    enum gprs_cipher_direction direction);
00042 };
00043 
00044 /* register a cipher with the core (from a plugin) */
00045 int gprs_cipher_register(struct gprs_cipher_impl *ciph);
00046 
00047 /* load all available GPRS cipher plugins */
00048 int gprs_cipher_load(const char *path);
00049 
00050 /* function to be called by core code */
00051 int gprs_cipher_run(uint8_t *out, uint16_t len, enum gprs_ciph_algo algo,
00052                     uint8_t *kc, uint32_t iv, enum gprs_cipher_direction dir);
00053 
00054 /* Do we have an implementation for this cipher? */
00055 int gprs_cipher_supported(enum gprs_ciph_algo algo);
00056 
00057 /* Return key length for supported cipher, in bytes */
00058 unsigned gprs_cipher_key_length(enum gprs_ciph_algo algo);
00059 
00060 /* GSM TS 04.64 / Section A.2.1 : Generation of 'input' */
00061 uint32_t gprs_cipher_gen_input_ui(uint32_t iov_ui, uint8_t sapi, uint32_t lfn, uint32_t oc);
00062 
00063 /* GSM TS 04.64 / Section A.2.1 : Generation of 'input' */
00064 uint32_t gprs_cipher_gen_input_i(uint32_t iov_i, uint32_t lfn, uint32_t oc);
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