This example expands on the definition of crypto_accelerator (p4lang#53…

…).

The example adds two methods for encrypt/decrypt that assumes that inline accelerators operate immediately on the packet (e.g. deparse, decrypt and reparse).  Packet recirculation is not necessary for either inline method.
The example shows the use of inline encrypt and decrypt, as well as how the crypto accelerator results can be used.

examples/include/crypto-accelerator.p4

@@ -28,6 +28,12 @@ enum crypto_results_e {
     HW_ERROR
 }
 
+enum crypto_mode_e {
+    TUNNEL,
+    TRANSPORT,
+    TRANSPORT_NAT_T
+}
+
 /// special value to indicate that ICV is after the crypto payload
 #define ICV_AFTER_PAYLOAD ((int<32>)-1)
 
@@ -122,6 +128,55 @@ extern crypto_accelerator {
     void enable_encrypt<T>(in T enable_auth);
     void enable_decrypt<T>(in T enable_auth);
 
+    // crypto accelerator runs immediately and returns control flow to the current pipeline
+    // stage. The method is responsible for defining the contents of the ESP header, 
+    // calculating the payload offset and lengths, encrypting the payload appropriately and 
+    // reparsing the packet. User can decide if to proceed or reinject.
+    //
+    // Pre-conditions: The parser must have been executed prior to this extern. The packet 
+    // headers and metadata from the parser are provided as inout params.
+    // Post-conditions: The deparser will be executed prior to encapsulation, the packet 
+    // bytestream will be updated and encryption will be performed on the payload. The 
+    // packet will be reparsed and parser states updated.
+    // Side-effects: parser states will be re-evaluated if crypto has succeeded.
+    //
+    // H - inout Headers is the output of the parser block
+    // M - inout Metadata is from the parser block and shared with the control 
+    // T - in enable_auth flag enables authentication check
+    // S - in seq is the optional sequence number
+    // I - in iv is the initialization vector
+    crypto_results_e encrypt_inline<H,M,T,S,I>(packet_in pkt,
+                        inout H hdr, 
+                        inout M meta,
+                        in crypto_mode_e mode,
+                        in T enable_auth,
+                        in bit<32> spi,
+                        in S seq,
+                        in I iv);
+
+    // crypto accelerator runs immediately and returns control flow to the current pipeline
+    // stage. The method is responsible for decrypting the payload appropriately, removing
+    // the ESP header, calculating the payload offset and lengths, and reparsing the packet.
+    // The user should then check the status.
+    //
+    // Pre-conditions: The parser will have been executed prior to this extern. The packet 
+    // headers and metadata from the parser are provided as inout params.
+    // Post-conditions: The deparser will be executed prior to decapsulation, the packet
+    // bytestream will be updated and decryption will be performed on the payload. The 
+    // packet will be reparsed and parser states recalculated.
+    // Side-effects: parser states will be re-evaluated if crypto has succeeded.
+    //
+    // H - inout Headers is the output of the parser block
+    // M - inout Metadata is from the parser block and shared with the control 
+    // T - in enable_auth flag enables authentication check
+    // S - in seq is the optional sequence number
+    crypto_results_e decrypt_inline<H,M,T,S>(packet_in pkt,
+                        inout H hdr,
+                        inout M meta,
+                        in crypto_mode_e mode,
+                        in T enable_auth,
+                        in S seq);
+
     // disable crypto engine. Between enable and disable methods,
     // whichever method is called last overrides the previous calls
     void disable();