# ibv_modify_flow_action

## NAME



           ibv_flow_action_esp - Flow action esp for verbs
    


## SYNOPSIS



                  #include <infiniband/verbs.h>
    
                  struct ibv_flow_action *
                  ibv_create_flow_action_esp(struct ibv_context *ctx,
                                 struct ibv_flow_action_esp *esp);
                  int
                  ibv_modify_flow_action_esp(struct ibv_flow_action *action,
                                 struct ibv_flow_action_esp *esp);
    
                  int ibv_destroy_flow_action(struct ibv_flow_action *action);
    


## DESCRIPTION



           An IPSEC ESP flow steering action allows a flow steering rule to
           decrypt or encrypt a packet after matching.  Each action contains
           the necessary information for this operation in the _params_
           argument.
    
           After the crypto operation the packet will continue to be
           processed by flow steering rules until it reaches a final action
           of discard or delivery.
    
           After the action is created, then it should be associated with a
           _struct ibv_flow_attr_ using _struct ibv_flow_spec_action_handle_ flow
           specification.  Each action can be associated with multiple flows,
           and _ibv_modify_flow_action_esp_ will alter all associated flows
           simultaneously.
    


## ARGUMENTS



           _ctx_    RDMA device context to create the action on.
    
           _esp_    ESP parameters and key material for the action.
    
           _action_ Existing action to modify ESP parameters.
    
       _**action** _Argument
                  struct ibv_flow_action_esp {
                      struct ibv_flow_action_esp_attr *esp_attr;
    
                      /* See Key Material */
                      uint16_t        keymat_proto;
                      uint16_t        keymat_len;
                      void           *keymat_ptr;
    
                      /* See Replay Protection */
                      uint16_t        replay_proto;
                      uint16_t        replay_len;
                      void           *replay_ptr;
    
                      struct ibv_flow_action_esp_encap *esp_encap;
    
                      uint32_t        comp_mask;
                      uint32_t        esn;
                  };
    
           _comp_mask_
                  Bitmask specifying what fields in the structure are valid.
    
           _esn_    The starting value of the ESP extended sequence number.
                  Valid only if _IBV_FLOW_ACTION_ESP_MASK_ESN_ is set in
                  _comp_mask_.
    
                  The 32 bits of _esn_ will be used to compute the full 64 bit
                  ESN required for the AAD construction.
    
                  When in _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_INLINE_CRYPTO_ mode,
                  the implementation will automatically track rollover of the
                  lower 32 bits of the ESN.  However, an update of the window
                  is required once every 2^31 sequences.
    
                  When in _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_FULL_OFFLOAD_ mode
                  this value is automatically incremended and it is also used
                  for anti-replay checks.
    
           _esp_attr_
                  See _ESP Attributes_.  May be NULL on modify.
    
           _keymat_proto_ , _keymat_len_ , _keymat_ptr_
                  Describe the key material and encryption standard to use.
                  May be NULL on modify.
    
           _replay_proto_ , _replay_len_ , _replay_ptr_
                  Describe the replay protection scheme used to manage
                  sequence numbers and prevent replay attacks.  This field is
                  only valid in full offload mode.  May be NULL on modify.
    
           _esp_encap_
                  Describe the encapsulation of ESP packets such as the IP
                  tunnel and/or UDP encapsulation.  This field is only valid
                  in full offload mode.  May be NULL on modify.
    
       **ESP attributes**
                  struct ibv_flow_action_esp_attr {
                      uint32_t   spi;
                      uint32_t   seq;
                      uint32_t   tfc_pad;
                      uint32_t   flags;
                      uint64_t   hard_limit_pkts;
                  };
    
           _flags_  A bitwise OR of the various _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_
                  described below.
    
                  _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_DECRYPT_ ,
                  _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_ENCRYPT_
                         The action will decrypt or encrypt a packet using
                         the provided keying material.
    
                         The implementation may require that encrypt is only
                         used with an egress flow steering rule, and that
                         decrypt is only used with an ingress flow steering
                         rule.
    
       **Full Offload Mode**
           When _esp_attr_ flag _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_FULL_OFFLOAD_ is
           set the ESP header and trailer are added and removed automatically
           during the cipher operation.  In this case the _esn_ and _spi_ are
           used to populate and check the ESP header, and any information
           from the _keymat_ (eg a IV) is placed in the headers and otherwise
           handled automatically.
    
           For decrypt the hardware will perform anti-replay.
    
           Decryption failure will cause the packet to be dropped.
    
           This action must be combined with the flow steering that
           identifies the packets protected by the SA defined in this action.
    
           The following members of the esp_attr are used only in full
           offload mode:
    
           _spi_    The value for the ESP Security Parameters Index.  It is
                  only used for _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_FULL_OFFLAOD_.
    
           _seq_    The initial 32 lower bytes of the sequence number.  This is
                  the value of the ESP sequence number.  It is only used for
                  _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_FULL_OFFLAOD_.
    
           _tfc_pad_
                  The length of Traffic Flow Confidentiality Padding as
                  specified by RFC4303.  If it is set to zero no additional
                  padding is added.  It is only used for
                  _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_FULL_OFFLAOD_.
    
           _hard_limit_pkts_
                  The hard lifetime of the SA measured in number of packets.
                  As specified by RFC4301.  After this limit is reached the
                  action will drop future packets to prevent breaking the
                  crypto.  It is only used for
                  _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_FULL_OFFLAOD_.
    
       **Inline Crypto Mode**
           When _esp_attr_ flag _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_INLINE_CRYPTO_
           is set the user must providate packets with additional headers.
    
           For encrypt the packet must contain a fully populated IPSEC packet
           except the data payload is left un-encrypted and there is no IPsec
           trailer.  If the IV must be unpredictable, then a flag should
           indicate the transofrmation such as
           _IB_UVERBS_FLOW_ACTION_IV_ALGO_SEQ_.
    
           _IB_UVERBS_FLOW_ACTION_IV_ALGO_SEQ_ means that the IV is incremented
           sequentually.  If the IV algorithm is supported by HW, then it
           could provide support for LSO offload with ESP inline crypto.
    
           Finally, the IV used to encrypt the packet replaces the IV field
           provided, the payload is encrypted and authenticated, a trailer
           with padding is added and the ICV is added as well.
    
           For decrypt the packet is authenticated and decrypted in-place,
           resulting in a decrypted IPSEC packet with no trailer.  The result
           of decryption and authentication can be retrieved from an extended
           CQ via the _ibv_wc_read_XXX(3)_ function.
    
           This mode must be combined with the flow steering including
           _IBV_FLOW_SPEC_IPV4_ and _IBV_FLOW_SPEC_ESP_ to match the outer packet
           headers to ensure that the action is only applied to IPSEC packets
           with the correct identifiers.
    
           For inline crypto, we have some special requirements to maintain a
           stateless ESN while maintaining the same parameters as software.
           The system supports offloading a portion of the IPSEC flow,
           enabling a single flow to be split between multiple NICs.
    
       **Determining the ESN for Ingress Packets**
           We require a “modify” command once every 2^31 packets.  This
           modify command allows the implementation in HW to be stateless, as
           follows:
    
                             ESN 1                       ESN 2                      ESN 3
                  |-------------*-------------|-------------*-------------|-------------*
                  ^             ^             ^             ^             ^             ^
    
           ^ - marks where command invoked to update the SA ESN state
           machine.
           | - marks the start of the ESN scope (0-2^32-1).  At this point
           move SA ESN “new_window” bit to zero and increment ESN.
           * - marks the middle of the ESN scope (2^31).  At this point move
           SA ESN “new_window” bit to one.
    
           For decryption the implementation uses the following state machine
           to determine ESN:
    
                  if (!overlap) {
                      use esn // regardless of packet.seq
                  } else { // new_window
                      if (packet.seq >= 2^31)
                          use esn
                      else // packet.seq < 2^31
                          use esn+1
                  }
    
           This mechanism is controlled by the _esp_attr_ flag:
    
           _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_ESN_NEW_WINDOW_
                  This flag is only used to provide stateless ESN support for
                  inline crypto.  It is used only for
                  _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_INLINE_CRYPTO_ and
                  _IBV_FLOW_ACTION_ESP_MASK_ESN_.
    
                  Setting this flag indicates that the bottom of the replay
                  window is between 2^31 - 2^32.
    
       **Key Material for AES GCM (_IBV_ACTION_ESP_KEYMAT_AES_GCM_**)
           The AES GCM crypto algorithm as defined by RFC4106.  This struct
           is to be provided in _keymat_ptr_ when _keymat_proto_ is set to
           _IBV_ACTION_ESP_KEYMAT_AES_GCM_.
    
                  struct ibv_flow_action_esp_aes_keymat_aes_gcm {
                      uint64_t   iv;
                      uint32_t   iv_algo; /* Use enum ib_uverbs_flow_action_esp_aes_gcm_keymat_iv_algo */
    
                      uint32_t   salt;
                      uint32_t   icv_len;
    
                      uint32_t   key_len;
                      uint32_t   aes_key[256 / 32];
                  };
    
           _iv_     The starting value for the initialization vector used only
                  with _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_FULL_OFFLOAD_
                  encryption as defined in RFC4106.  This field is ignored
                  for _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_INLINE_CRYPTO_.
    
                  For a given key, the IV MUST NOT be reused.
    
           _iv_algo_
                  The algorithm used to transform/generate new IVs with
                  _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_FULL_OFFLOAD_ encryption.
    
                  The only supported value is
                  _IB_UVERBS_FLOW_ACTION_IV_ALGO_SEQ_ to generate sequantial
                  IVs.
    
           _salt_   The salt as defined by RFC4106.
    
           _icv_len_
                  The length of the Integrity Check Value in bytes as defined
                  by RFC4106.
    
           _aes_key_ , _key_len_
                  The cipher key data.  It must be either 16, 24 or 32 bytes
                  as defined by RFC4106.
    
       **Bitmap Replay Protection (_IBV_FLOW_ACTION_ESP_REPLAY_BMP_**)
           A shifting bitmap is used to identify which packets have already
           been transmitted.  Each bit in the bitmap represents a packet, it
           is set if a packet with this ESP sequence number has been received
           and it passed authentication.  If a packet with the same sequence
           is received, then the bit is already set, causing replay
           protection to drop the packet.  The bitmap represents a window of
           _size_ sequence numbers.  If a newer sequence number is received,
           then the bitmap will shift to represent this as in RFC6479.  The
           replay window cannot shift more than 2^31 sequence numbers
           forward.
    
           This struct is to be provided in _replay_ptr_ when _reply_proto_ is
           set to _IBV_FLOW_ACTION_ESP_REPLAY_BMP_.  In this mode reply_ptr and
           reply_len should point to a struct ibv_flow_action_esp_replay_bmp
           containing: _size_ : The size of the bitmap.
    
       **ESP Encapsulation**
           An _esp_encap_ specification is required when _eps_attr_ flags
           _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_TUNNEL_ is set.  It is used to
           provide the fields for the encapsulation header that is
           added/removed to/from packets.  Tunnel and Transport mode are
           defined as in RFC4301.  UDP encapsulation of ESP can be specified
           by providing the appropriate UDP header.
    
           This setting is only used in
           _IB_UVERBS_FLOW_ACTION_ESP_FLAGS_FULL_OFFLOAD_ mode.
    
                  struct ibv_flow_action_esp_encap {
                      void        *val;        /* pointer to struct ibv_flow_xxxx_filter */
                      struct ibv_flow_action_esp_encap   *next_ptr;
                      uint16_t    len;            /* Len of mask and pointer (separately) */
                      uint16_t    type;           /* Use flow_spec enum */
                  };
    
           Each link in the list specifies a network header in the same
           manner as the flow steering API.  The header should be selected
           from a supported header in `enum ibv_flow_spec_type'.
    


## RETURN VALUE



           Upon success _ibv_create_flow_action_esp_ will return a new _struct_
           _ibv_flow_action_ object, on error NULL will be returned and errno
           will be set.
    
           Upon success _ibv_modify_action_esp_ will return 0.  On error the
           value of errno will be returned.  If ibv_modify_flow_action fails,
           it is guaranteed that the last action still holds.  If it
           succeeds, there is a point in the future where the old action is
           applied on all packets until this point and the new one is applied
           on all packets from this point and on.
    


* * *