13. Security Library
The security library provides a framework for management and provisioning of security protocol operations offloaded to hardware based devices. The library defines generic APIs to create and free security sessions which can support full protocol offload as well as inline crypto operation with NIC or crypto devices. The framework currently only supports the IPSec protocol and associated operations, other protocols will be added in future.
13.1. Design Principles
The security library provides an additional offload capability to an existing crypto device and/or ethernet device.
+---------------+
| rte_security |
+---------------+
\ /
+-----------+ +--------------+
| NIC PMD | | CRYPTO PMD |
+-----------+ +--------------+
Note
Currently, the security library does not support the case of multi-process. It will be updated in the future releases.
The supported offload types are explained in the sections below.
13.1.1. Inline Crypto
RTE_SECURITY_ACTION_TYPE_INLINE_CRYPTO: The crypto processing for security protocol (e.g. IPSec) is processed inline during receive and transmission on NIC port. The flow based security action should be configured on the port.
Ingress Data path - The packet is decrypted in RX path and relevant crypto status is set in Rx descriptors. After the successful inline crypto processing the packet is presented to host as a regular Rx packet however all security protocol related headers are still attached to the packet. e.g. In case of IPSec, the IPSec tunnel headers (if any), ESP/AH headers will remain in the packet but the received packet contains the decrypted data where the encrypted data was when the packet arrived. The driver Rx path check the descriptors and based on the crypto status sets additional flags in the rte_mbuf.ol_flags field.
Note
The underlying device may not support crypto processing for all ingress packet matching to a particular flow (e.g. fragmented packets), such packets will be passed as encrypted packets. It is the responsibility of application to process such encrypted packets using other crypto driver instance.
Egress Data path - The software prepares the egress packet by adding relevant security protocol headers. Only the data will not be encrypted by the software. The driver will accordingly configure the tx descriptors. The hardware device will encrypt the data before sending the packet out.
Note
The underlying device may support post encryption TSO.
Egress Data Path
|
+--------|--------+
| egress IPsec |
| | |
| +------V------+ |
| | SADB lookup | |
| +------|------+ |
| +------V------+ |
| | Tunnel | | <------ Add tunnel header to packet
| +------|------+ |
| +------V------+ |
| | ESP | | <------ Add ESP header without trailer to packet
| | | | <------ Mark packet to be offloaded, add trailer
| +------|------+ | meta-data to mbuf
+--------V--------+
|
+--------V--------+
| L2 Stack |
+--------|--------+
|
+--------V--------+
| |
| NIC PMD | <------ Set hw context for inline crypto offload
| |
+--------|--------+
|
+--------|--------+
| HW ACCELERATED | <------ Packet Encryption and
| NIC | Authentication happens inline
| |
+-----------------+
13.1.2. Inline protocol offload
RTE_SECURITY_ACTION_TYPE_INLINE_PROTOCOL: The crypto and protocol processing for security protocol (e.g. IPSec) is processed inline during receive and transmission. The flow based security action should be configured on the port.
Ingress Data path - The packet is decrypted in the RX path and relevant
crypto status is set in the Rx descriptors. After the successful inline
crypto processing the packet is presented to the host as a regular Rx packet
but all security protocol related headers are optionally removed from the
packet. e.g. in the case of IPSec, the IPSec tunnel headers (if any),
ESP/AH headers will be removed from the packet and the received packet
will contains the decrypted packet only. The driver Rx path checks the
descriptors and based on the crypto status sets additional flags in
rte_mbuf.ol_flags field.
Note
The underlying device in this case is stateful. It is expected that the device shall support crypto processing for all kind of packets matching to a given flow, this includes fragmented packets (post reassembly). E.g. in case of IPSec the device may internally manage anti-replay etc. It will provide a configuration option for anti-replay behavior i.e. to drop the packets or pass them to driver with error flags set in the descriptor.
Egress Data path - The software will send the plain packet without any security protocol headers added to the packet. The driver will configure the security index and other requirement in tx descriptors. The hardware device will do security processing on the packet that includes adding the relevant protocol headers and encrypting the data before sending the packet out. The software should make sure that the buffer has required head room and tail room for any protocol header addition. The software may also do early fragmentation if the resultant packet is expected to cross the MTU size.
Note
The underlying device will manage state information required for egress processing. E.g. in case of IPSec, the seq number will be added to the packet, however the device shall provide indication when the sequence number is about to overflow. The underlying device may support post encryption TSO.
Egress Data Path
|
+--------|--------+
| egress IPsec |
| | |
| +------V------+ |
| | SADB lookup | |
| +------|------+ |
| +------V------+ |
| | Desc | | <------ Mark packet to be offloaded
| +------|------+ |
+--------V--------+
|
+--------V--------+
| L2 Stack |
+--------|--------+
|
+--------V--------+
| |
| NIC PMD | <------ Set hw context for inline crypto offload
| |
+--------|--------+
|
+--------|--------+
| HW ACCELERATED | <------ Add tunnel, ESP header etc header to
| NIC | packet. Packet Encryption and
| | Authentication happens inline.
+-----------------+
13.1.3. Lookaside protocol offload
RTE_SECURITY_ACTION_TYPE_LOOKASIDE_PROTOCOL: This extends librte_cryptodev to support the programming of IPsec Security Association (SA) as part of a crypto session creation including the definition. In addition to standard crypto processing, as defined by the cryptodev, the security protocol processing is also offloaded to the crypto device.
Decryption: The packet is sent to the crypto device for security protocol processing. The device will decrypt the packet and it will also optionally remove additional security headers from the packet. E.g. in case of IPSec, IPSec tunnel headers (if any), ESP/AH headers will be removed from the packet and the decrypted packet may contain plain data only.
Note
In case of IPSec the device may internally manage anti-replay etc. It will provide a configuration option for anti-replay behavior i.e. to drop the packets or pass them to driver with error flags set in descriptor.
Encryption: The software will submit the packet to cryptodev as usual for encryption, the hardware device in this case will also add the relevant security protocol header along with encrypting the packet. The software should make sure that the buffer has required head room and tail room for any protocol header addition.
Note
In the case of IPSec, the seq number will be added to the packet, It shall provide an indication when the sequence number is about to overflow.
Egress Data Path
|
+--------|--------+
| egress IPsec |
| | |
| +------V------+ |
| | SADB lookup | | <------ SA maps to cryptodev session
| +------|------+ |
| +------|------+ |
| | \--------------------\
| | Crypto | | | <- Crypto processing through
| | /----------------\ | inline crypto PMD
| +------|------+ | | |
+--------V--------+ | |
| | |
+--------V--------+ | | create <-- SA is added to hw
| L2 Stack | | | inline using existing create
+--------|--------+ | | session sym session APIs
| | | |
+--------V--------+ +---|---|----V---+
| | | \---/ | | <--- Add tunnel, ESP header etc
| NIC PMD | | INLINE | | header to packet.Packet
| | | CRYPTO PMD | | Encryption/Decryption and
+--------|--------+ +----------------+ Authentication happens
| inline.
+--------|--------+
| NIC |
+--------|--------+
V
13.2. Device Features and Capabilities
13.2.1. Device Capabilities For Security Operations
The device (crypto or ethernet) capabilities which support security operations, are defined by the security action type, security protocol, protocol capabilities and corresponding crypto capabilities for security. For the full scope of the Security capability see definition of rte_security_capability structure in the DPDK API Reference.
struct rte_security_capability;
Each driver (crypto or ethernet) defines its own private array of capabilities for the operations it supports. Below is an example of the capabilities for a PMD which supports the IPSec protocol.
static const struct rte_security_capability pmd_security_capabilities[] = {
{ /* IPsec Lookaside Protocol offload ESP Tunnel Egress */
.action = RTE_SECURITY_ACTION_TYPE_LOOKASIDE_PROTOCOL,
.protocol = RTE_SECURITY_PROTOCOL_IPSEC,
.ipsec = {
.proto = RTE_SECURITY_IPSEC_SA_PROTO_ESP,
.mode = RTE_SECURITY_IPSEC_SA_MODE_TUNNEL,
.direction = RTE_SECURITY_IPSEC_SA_DIR_EGRESS,
.options = { 0 }
},
.crypto_capabilities = pmd_capabilities
},
{ /* IPsec Lookaside Protocol offload ESP Tunnel Ingress */
.action = RTE_SECURITY_ACTION_TYPE_LOOKASIDE_PROTOCOL,
.protocol = RTE_SECURITY_PROTOCOL_IPSEC,
.ipsec = {
.proto = RTE_SECURITY_IPSEC_SA_PROTO_ESP,
.mode = RTE_SECURITY_IPSEC_SA_MODE_TUNNEL,
.direction = RTE_SECURITY_IPSEC_SA_DIR_INGRESS,
.options = { 0 }
},
.crypto_capabilities = pmd_capabilities
},
{
.action = RTE_SECURITY_ACTION_TYPE_NONE
}
};
static const struct rte_cryptodev_capabilities pmd_capabilities[] = {
{ /* SHA1 HMAC */
.op = RTE_CRYPTO_OP_TYPE_SYMMETRIC,
.sym = {
.xform_type = RTE_CRYPTO_SYM_XFORM_AUTH,
.auth = {
.algo = RTE_CRYPTO_AUTH_SHA1_HMAC,
.block_size = 64,
.key_size = {
.min = 64,
.max = 64,
.increment = 0
},
.digest_size = {
.min = 12,
.max = 12,
.increment = 0
},
.aad_size = { 0 },
.iv_size = { 0 }
}
}
},
{ /* AES CBC */
.op = RTE_CRYPTO_OP_TYPE_SYMMETRIC,
.sym = {
.xform_type = RTE_CRYPTO_SYM_XFORM_CIPHER,
.cipher = {
.algo = RTE_CRYPTO_CIPHER_AES_CBC,
.block_size = 16,
.key_size = {
.min = 16,
.max = 32,
.increment = 8
},
.iv_size = {
.min = 16,
.max = 16,
.increment = 0
}
}
}
}
}
13.2.2. Capabilities Discovery
Discovering the features and capabilities of a driver (crypto/ethernet)
is achieved through the rte_security_capabilities_get() function.
const struct rte_security_capability *rte_security_capabilities_get(uint16_t id);
This allows the user to query a specific driver and get all device
security capabilities. It returns an array of rte_security_capability structures
which contains all the capabilities for that device.
13.2.3. Security Session Create/Free
Security Sessions are created to store the immutable fields of a particular Security Association for a particular protocol which is defined by a security session configuration structure which is used in the operation processing of a packet flow. Sessions are used to manage protocol specific information as well as crypto parameters. Security sessions cache this immutable data in a optimal way for the underlying PMD and this allows further acceleration of the offload of Crypto workloads.
The Security framework provides APIs to create and free sessions for crypto/ethernet devices, where sessions are mempool objects. It is the application’s responsibility to create and manage the session mempools. The mempool object size should be able to accommodate the driver’s private data of security session.
Once the session mempools have been created, rte_security_session_create()
is used to allocate and initialize a session for the required crypto/ethernet device.
Session APIs need a parameter rte_security_ctx to identify the crypto/ethernet
security ops. This parameter can be retrieved using the APIs
rte_cryptodev_get_sec_ctx() (for crypto device) or rte_eth_dev_get_sec_ctx
(for ethernet port).
Sessions already created can be updated with rte_security_session_update().
When a session is no longer used, the user must call rte_security_session_destroy()
to free the driver private session data and return the memory back to the mempool.
For look aside protocol offload to hardware crypto device, the rte_crypto_op
created by the application is attached to the security session by the API
rte_security_attach_session().
For Inline Crypto and Inline protocol offload, device specific defined metadata is
updated in the mbuf using rte_security_set_pkt_metadata() if
DEV_TX_OFFLOAD_SEC_NEED_MDATA is set.
13.2.4. Security session configuration
Security Session configuration structure is defined as rte_security_session_conf
struct rte_security_session_conf {
enum rte_security_session_action_type action_type;
/**< Type of action to be performed on the session */
enum rte_security_session_protocol protocol;
/**< Security protocol to be configured */
union {
struct rte_security_ipsec_xform ipsec;
struct rte_security_macsec_xform macsec;
};
/**< Configuration parameters for security session */
struct rte_crypto_sym_xform *crypto_xform;
/**< Security Session Crypto Transformations */
};
The configuration structure reuses the rte_crypto_sym_xform struct for crypto related
configuration. The rte_security_session_action_type struct is used to specify whether the
session is configured for Lookaside Protocol offload or Inline Crypto or Inline Protocol
Offload.
enum rte_security_session_action_type {
RTE_SECURITY_ACTION_TYPE_NONE,
/**< No security actions */
RTE_SECURITY_ACTION_TYPE_INLINE_CRYPTO,
/**< Crypto processing for security protocol is processed inline
* during transmission */
RTE_SECURITY_ACTION_TYPE_INLINE_PROTOCOL,
/**< All security protocol processing is performed inline during
* transmission */
RTE_SECURITY_ACTION_TYPE_LOOKASIDE_PROTOCOL
/**< All security protocol processing including crypto is performed
* on a lookaside accelerator */
};
The rte_security_session_protocol is defined as
enum rte_security_session_protocol {
RTE_SECURITY_PROTOCOL_IPSEC,
/**< IPsec Protocol */
RTE_SECURITY_PROTOCOL_MACSEC,
/**< MACSec Protocol */
};
Currently the library defines configuration parameters for IPSec only. For other protocols like MACSec, structures and enums are defined as place holders which will be updated in the future.
IPsec related configuration parameters are defined in rte_security_ipsec_xform
struct rte_security_ipsec_xform {
uint32_t spi;
/**< SA security parameter index */
uint32_t salt;
/**< SA salt */
struct rte_security_ipsec_sa_options options;
/**< various SA options */
enum rte_security_ipsec_sa_direction direction;
/**< IPSec SA Direction - Egress/Ingress */
enum rte_security_ipsec_sa_protocol proto;
/**< IPsec SA Protocol - AH/ESP */
enum rte_security_ipsec_sa_mode mode;
/**< IPsec SA Mode - transport/tunnel */
struct rte_security_ipsec_tunnel_param tunnel;
/**< Tunnel parameters, NULL for transport mode */
};
13.2.5. Security API
The rte_security Library API is described in the DPDK API Reference document.
13.2.6. Flow based Security Session
In the case of NIC based offloads, the security session specified in the ‘rte_flow_action_security’ must be created on the same port as the flow action that is being specified.
The ingress/egress flow attribute should match that specified in the security session if the security session supports the definition of the direction.
Multiple flows can be configured to use the same security session. For example if the security session specifies an egress IPsec SA, then multiple flows can be specified to that SA. In the case of an ingress IPsec SA then it is only valid to have a single flow to map to that security session.
Configuration Path
|
+--------|--------+
| Add/Remove |
| IPsec SA | <------ Build security flow action of
| | | ipsec transform
|--------|--------|
|
+--------V--------+
| Flow API |
+--------|--------+
|
+--------V--------+
| |
| NIC PMD | <------ Add/Remove SA to/from hw context
| |
+--------|--------+
|
+--------|--------+
| HW ACCELERATED |
| NIC |
| |
+--------|--------+
- Add/Delete SA flow:
To add a new inline SA construct a rte_flow_item for Ethernet + IP + ESP
using the SA selectors and the
rte_crypto_ipsec_xformas therte_flow_action. Note that any rte_flow_items may be empty, which means it is not checked.
In its most basic form, IPsec flow specification is as follows:
+-------+ +----------+ +--------+ +-----+
| Eth | -> | IP4/6 | -> | ESP | -> | END |
+-------+ +----------+ +--------+ +-----+
However, the API can represent, IPsec crypto offload with any encapsulation:
+-------+ +--------+ +-----+
| Eth | -> ... -> | ESP | -> | END |
+-------+ +--------+ +-----+