engine.h (3591B)
1 // Copyright 2014 The BoringSSL Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef OPENSSL_HEADER_ENGINE_H 16 #define OPENSSL_HEADER_ENGINE_H 17 18 #include <openssl/base.h> // IWYU pragma: export 19 20 #if defined(__cplusplus) 21 extern "C" { 22 #endif 23 24 25 // Engines are collections of methods. Methods are tables of function pointers, 26 // defined for certain algorithms, that allow operations on those algorithms to 27 // be overridden via a callback. This can be used, for example, to implement an 28 // RSA* that forwards operations to a hardware module. 29 // 30 // Methods are reference counted but |ENGINE|s are not. When creating a method, 31 // you should zero the whole structure and fill in the function pointers that 32 // you wish before setting it on an |ENGINE|. Any functions pointers that 33 // are NULL indicate that the default behaviour should be used. 34 35 36 // Allocation and destruction. 37 38 // ENGINE_new returns an empty ENGINE that uses the default method for all 39 // algorithms. 40 OPENSSL_EXPORT ENGINE *ENGINE_new(void); 41 42 // ENGINE_free decrements the reference counts for all methods linked from 43 // |engine| and frees |engine| itself. It returns one. 44 OPENSSL_EXPORT int ENGINE_free(ENGINE *engine); 45 46 47 // Method accessors. 48 // 49 // Method accessors take a method pointer and the size of the structure. The 50 // size allows for ABI compatibility in the case that the method structure is 51 // extended with extra elements at the end. Methods are always copied by the 52 // set functions. 53 // 54 // Set functions return one on success and zero on allocation failure. 55 56 OPENSSL_EXPORT int ENGINE_set_RSA_method(ENGINE *engine, 57 const RSA_METHOD *method, 58 size_t method_size); 59 OPENSSL_EXPORT RSA_METHOD *ENGINE_get_RSA_method(const ENGINE *engine); 60 61 OPENSSL_EXPORT int ENGINE_set_ECDSA_method(ENGINE *engine, 62 const ECDSA_METHOD *method, 63 size_t method_size); 64 OPENSSL_EXPORT ECDSA_METHOD *ENGINE_get_ECDSA_method(const ENGINE *engine); 65 66 67 // Generic method functions. 68 // 69 // These functions take a void* type but actually operate on all method 70 // structures. 71 72 // METHOD_ref increments the reference count of |method|. This is a no-op for 73 // now because all methods are currently static. 74 void METHOD_ref(void *method); 75 76 // METHOD_unref decrements the reference count of |method| and frees it if the 77 // reference count drops to zero. This is a no-op for now because all methods 78 // are currently static. 79 void METHOD_unref(void *method); 80 81 82 // Private functions. 83 84 // openssl_method_common_st contains the common part of all method structures. 85 // This must be the first member of all method structures. 86 struct openssl_method_common_st { 87 int references; // dummy – not used. 88 char is_static; 89 }; 90 91 92 #if defined(__cplusplus) 93 } // extern C 94 95 extern "C++" { 96 97 BSSL_NAMESPACE_BEGIN 98 99 BORINGSSL_MAKE_DELETER(ENGINE, ENGINE_free) 100 101 BSSL_NAMESPACE_END 102 103 } // extern C++ 104 105 #endif 106 107 #define ENGINE_R_OPERATION_NOT_SUPPORTED 100 108 109 #endif // OPENSSL_HEADER_ENGINE_H