Example: crypto_accelerator object extern

examples/include/crypto-accelerator.p4

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+/*
+Copyright 2022 Advanced Micro Devices, Inc
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/// Crypto accelerator Extern definition
+
+/// Crypto accelerator object is instantiated for each crypto algorithm
+enum crypto_algorithm_e {
+    AES_GCM
+}
+
+/// Results from crypto accelerator
+enum crypto_results_e {
+    SUCCESS,
+    AUTH_FAILURE,
+    HW_ERROR
+}
+
+/// special value to indicate that ICV is after the crypto payload
+#define ICV_AFTER_PAYLOAD ((int<32>)-1)
+
+/// The crypto_accelerator engine used in this example uses AES-GCM algorithm.
+/// It is assumed to be agnostic to wire protocols i.e. does not understand protocol 
+/// specific headers like ESP, AH etc
+///
+/// The crypto accelerator does not modify the packet outside the payload area and ICV
+///     Any wire-protocol header, trailer add/remove is handled by P4 pipeline
+///     The engine does not perform additional functions such as anti-replay protection, it
+///     is done in P4 pipeline
+/// 
+/// Crypto Engine takes the following inputs:
+///     - key, iv, icv_location/size, enable_auth, auth_data (aka AAD), payload location
+///     In some protocols AAD can be present in the packet (e.g ESP header), in that case AAD
+///         can be specified as offset/len within the packet. Additional auth data 
+///         that is not part of the packet can also be provided
+///     On encrypt operation, icv_location/size indicates that icv is inserted in the
+///         packet at the specified packet offset
+///     On decrypt operation, icv_location and size is used for auth validation
+///
+/// Example:
+/// Encrypt operation:
+///     Parameters passed : key, iv, icv_location/size, enable_auth, auth_data
+///     Packet presented to the engine -
+///     +------------------+--------------------------+-----------+
+///     | Headers not to   | Encryption protocol      | payload   | 
+///     | be Encrypted     | headers (E.g Esp, Esp-IV)|           |
+///     +------------------+-----------------------  -+-----------+
+///     Packet after Encryption:
+///     +------------------+--------------------------+-----------+-----------+
+///     | Headers not to   | Encryption protocol      | Encrypted | ICV (opt) |
+///     | be Encrypted     | headers (E.g Esp, Esp-IV)| Payload   |           |
+///     +------------------+--------------------------+-----------+-----------+
+///     ICV can be inserted either before or right after the encrypted payload 
+///     as specified by icv_location/size
+///     Results: Success, Hardware Error
+///
+/// Decrypt operation:
+///     Parameters passed : key, iv, icv_location/size, enable_auth, auth_data
+///     Packet presented to the engine -
+///     +------------------+--------------------------+-----------+-----+
+///     | Headers not to   | Encryption protocol      | Encrypted | ICV |
+///     | Encrypted        | headers (E.g Esp, Esp-IV)| Payload   |     |
+///     +------------------+--------------------------+-----------+-----+
+///     Packet after decrytion:
+///     +------------------+--------------------------+-----------+-----+
+///     | Headers not to   | Encryption protocol      | cleartext | ICV |
+///     | Encrypted        | headers (E.g Esp, Esp-IV)| Payload   |     |
+///     +------------------+--  ----------------------+-----------+-----+
+///     Results: Success, Auth Failure, Hardware Error
+///
+extern crypto_accelerator {
+    /// constructor
+    /// Some methods provided in this object may be specific to an algorithm used.
+    /// Compiler may be able to check and warn/error when incorrect methods are used
+    crypto_accelerator(crypto_algorithm_e algo);
+
+
+    // security association index for this security session
+    // Some implementations do not need it.. in that case this method should result in no-op
+    void set_sa_index<T>(in T sa_index);
+
+    // Set the initialization data based on protocol used. E.g. salt, random number/ counter for ipsec
+    void set_iv<T>(in T iv);
+    void set_key<T,S>(in T key, in S key_size);   // 128, 192, 256
+
+    // The format of the auth data is not specified/mandated by this object definition
+    // If it is part of the packet, it can be specified using offset/len mothods below
+    void set_auth_data_offset<T>(in T offset);
+    void set_auth_data_len<T>(in T len);
+
+    // Alternatively: Following API can be used to consturct the auth_data and
+    // provide it to the engine.
+    void add_auth_data<H>(in H auth_data);
+
+    // Auth trailer aka ICV is added by the engine after doing encryption operation
+    // Specify icv location - when a wire protocol wants to add ICV in a specific location (e.g. AH)
+    // The following apis can be used to specify the location of ICV in the packet
+    // A special offset indicates ICV is after the payload
+    void set_icv_offset<T>(in T offset);
+    void set_icv_len<L>(in L len);
+
+    // setup payload to be encrypted/decrypted
+    void set_payload_offset<T>(in T offset);
+    void set_payload_len<T>(in T len);
+
+    // crypto accelerator runs at the end of the pipeline (after deparser), the following
+    // methods will enable the accelerator to run encrypt/decrypt operations
+    // enable_auth flag enables authentication check for decrypt. For encrypt operation,
+    // auth data computed, is added to specified icv_offset/len
+    void enable_encrypt<T>(in T enable_auth);
+    void enable_decrypt<T>(in T enable_auth);
+
+    // disable crypto engine. Between enable and disable methods,
+    // whichever method is called last overrides the previous calls
+    void disable();
+
+    // get results of the previous operation
+    crypto_results_e get_results();
+}