[dpdk-dev] [RFC] tunnel endpoint hw acceleration enablement

Shahaf Shuler shahafs at mellanox.com
Sun Dec 24 18:30:51 CET 2017


Hi Declan,

Friday, December 22, 2017 12:21 AM, Doherty, Declan:
> This RFC contains a proposal to add a new tunnel endpoint API to DPDK that
> when used in conjunction with rte_flow enables the configuration of inline
> data path encapsulation and decapsulation of tunnel endpoint network
> overlays on accelerated IO devices.
> 
> The proposed new API would provide for the creation, destruction, and
> monitoring of a tunnel endpoint in supporting hw, as well as capabilities APIs
> to allow the acceleration features to be discovered by applications.
> 
> /** Tunnel Endpoint context, opaque structure */ struct rte_tep;
> 
> enum rte_tep_type {
>                RTE_TEP_TYPE_VXLAN = 1, /**< VXLAN Protocol */
>                RTE_TEP_TYPE_NVGRE,     /**< NVGRE Protocol */
>                ...
> };
> 
> /** Tunnel Endpoint Attributes */
> struct rte_tep_attr {
>                enum rte_type_type type;
> 
>                /* other endpoint attributes here */ }
> 
> /**
> * Create a tunnel end-point context as specified by the flow attribute and
> pattern
> *
> * @param   port_id     Port identifier of Ethernet device.
> * @param   attr        Flow rule attributes.
> * @param   pattern     Pattern specification by list of rte_flow_items.
> * @return
> *  - On success returns pointer to TEP context
> *  - On failure returns NULL
> */
> struct rte_tep *rte_tep_create(uint16_t port_id,
>                               struct rte_tep_attr *attr, struct rte_flow_item pattern[])
> 
> /**
> * Destroy an existing tunnel end-point context. All the end-points context
> * will be destroyed, so all active flows using tep should be freed before
> * destroying context.
> * @param   port_id    Port identifier of Ethernet device.
> * @param   tep        Tunnel endpoint context
> * @return
> *  - On success returns 0
> *  - On failure returns 1
> */
> int rte_tep_destroy(uint16_t port_id, struct rte_tep *tep)
> 
> /**
> * Get tunnel endpoint statistics
> *
> * @param   port_id    Port identifier of Ethernet device.
> * @param   tep        Tunnel endpoint context
> * @param   stats      Tunnel endpoint statistics
> *
> * @return
> *  - On success returns 0
> *  - On failure returns 1
> */
> Int
> rte_tep_stats_get(uint16_t port_id, struct rte_tep *tep,
>                               struct rte_tep_stats *stats)
> 
> /**
> * Get ports tunnel endpoint capabilities
> *
> * @param   port_id    Port identifier of Ethernet device.
> * @param   capabilities        Tunnel endpoint capabilities
> *
> * @return
> *  - On success returns 0
> *  - On failure returns 1
> */
> int
> rte_tep_capabilities_get(uint16_t port_id,
>                               struct rte_tep_capabilities *capabilities)


Am not sure I understand why there is a need for the above control methods. 
Are you introducing a new "tep device" ? 
As the tunnel endpoint is sending and receiving Ethernet packets from the network I think it should still be counted as Ethernet device but with more capabilities (for example it supported encap/decap etc..), therefore it should use the Ethdev layer API to query statistics (for example). 
As for the capabilities - what specifically you had in mind? The current usage you show with tep is with rte_flow rules. There are no capabilities currently for rte_flow supported actions/pattern. To check such capabilities application uses rte_flow_validate. 
Regarding the creation/destroy of tep. Why not simply use rte_flow API and avoid this extra control? 
For example - with 17.11 APIs, application can put the port in isolate mode, and insert a flow_rule to catch only IPv4 VXLAN traffic and direct to some queue/do RSS. Such operation, per my understanding, will create a tunnel endpoint. What are the down sides of doing it with the current APIs? 

> 
> 
> To direct traffic flows to hw terminated tunnel endpoint the rte_flow API is
> enhanced to add a new flow item type. This contains a pointer to the TEP
> context as well as the overlay flow id to which the traffic flow is associated.
> 
> struct rte_flow_item_tep {
>                struct rte_tep *tep;
>                uint32_t flow_id;
> }

Can you provide more detailed definition about the flow id ? to which field from the packet headers it refers to? 
On your below examples it looks like it is to match the VXLAN vni in case of VXLAN, what about the other protocols? And also, why not using the already exists VXLAN item? 

Generally I like the idea of separating the encap/decap context from the action. However looks like the rte_flow_item has double meaning on this RFC, once for the classification and once for the action.
>From the top of my head I would think of an API which separate those, and re-use the existing flow items. Something like:

 struct rte_flow_item pattern[] = {
                { set of already exists pattern  },
                { ... },
                { .type = RTE_FLOW_ITEM_TYPE_END } };

encap_ctx = create_enacap_context(pattern)

rte_flow_action actions[] = {
	{ .type RTE_FLOW_ITEM_ENCAP, .conf = encap_ctx}
}
 
> Also 2 new generic actions types are added encapsulation and decapsulation.
> 
> RTE_FLOW_ACTION_TYPE_ENCAP
> RTE_FLOW_ACTION_TYPE_DECAP
> 
> struct rte_flow_action_encap {
>                struct rte_flow_item *item; }
> 
> struct rte_flow_action_decap {
>                struct rte_flow_item *item; }
> 
> The following section outlines the intended usage of the new APIs and then
> how they are combined with the existing rte_flow APIs.
> 
> Tunnel endpoints are created on logical ports which support the capability
> using rte_tep_create() using a combination of TEP attributes and
> rte_flow_items. In the example below a new IPv4 VxLAN endpoint is being
> defined.
> The attrs parameter sets the TEP type, and could be used for other possible
> attributes.
> 
> struct rte_tep_attr attrs = { .type = RTE_TEP_TYPE_VXLAN };
> 
> The values for the headers which make up the tunnel endpointr are then
> defined using spec parameter in the rte flow items (IPv4, UDP and VxLAN in
> this case)
> 
> struct rte_flow_item_ipv4 ipv4_item = {
>                .hdr = { .src_addr = saddr, .dst_addr = daddr } };
> 
> struct rte_flow_item_udp udp_item = {
>                .hdr = { .src_port = sport, .dst_port = dport } };
> 
> struct rte_flow_item_vxlan vxlan_item = { .flags = vxlan_flags };
> 
> struct rte_flow_item pattern[] = {
>                { .type = RTE_FLOW_ITEM_TYPE_IPV4, .spec = &ipv4_item },
>                { .type = RTE_FLOW_ITEM_TYPE_UDP, .spec = &udp_item },
>                { .type = RTE_FLOW_ITEM_TYPE_VXLAN, .spec = &vxlan_item },
>                { .type = RTE_FLOW_ITEM_TYPE_END } };
> 
> The tunnel endpoint can then be create on the port. Whether or not any hw
> configuration is required at this point would be hw dependent, but if not the
> context for the TEP is available for use in programming flow, so the
> application is not forced to redefine the TEP parameters on each flow
> addition.
> 
> struct rte_tep *tep = rte_tep_create(port_id, &attrs, pattern);
> 
> Once the tep context is created flows can then be directed to that endpoint
> for processing. The following sections will outline how the author envisage
> flow programming will work and also how TEP acceleration can be combined
> with other accelerations.
> 
> 
> Ingress TEP decapsulation, mark and forward to queue:
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> The flows definition for TEP decapsulation actions should specify the full
> outer packet to be matched at a minimum. The outer packet definition
> should match the tunnel definition in the tep context and the tep flow id.
> This example shows describes matching on the outer, marking the packet
> with the VXLAN VNI and directing to a specified queue of the port.
> 
> Source Packet
> 
>        Decapsulate Outer Hdr
>      /                       \                                    decap outer crc
>     /                         \                                    /          \
>     +-----+------+-----+-------+-----+------+-----+---------+-----+-----------+
>     | ETH | IPv4 | UDP | VxLAN | ETH | IPv4 | TCP | PAYLOAD | CRC | OUTER
> CRC |
>     +-----+------+-----+-------+-----+------+-----+---------+-----+-----------+
> 
> /* Flow Attributes/Items Definitions */
> 
> struct rte_flow_attr attr = { .ingress = 1 };
> 
> struct rte_flow_item_eth eth_item = { .src = s_addr, .dst = d_addr, .type =
> ether_type }; struct rte_flow_item_tep tep_item = { .tep = tep, .id = vni };
> 
> struct rte_flow_item pattern[] = {
>                { .type = RTE_FLOW_ITEM_TYPE_ETH, .spec = &eth_item },
>                { .type = RTE_FLOW_ITEM_TYPE_TEP, .spec = &tep_item  },
>                { .type = RTE_FLOW_ITEM_TYPE_END } };
> 
> /* Flow Actions Definitions */
> 
> struct rte_flow_action_decap decap_eth = {
>                .type = RTE_FLOW_ITEM_TYPE_ETH,
>                .item = { .src = s_addr, .dst = d_addr, .type = ether_type } };
> 
> struct rte_flow_action_decap decap_tep = {
>                .type = RTE_FLOW_ITEM_TYPE_TEP, .spec = &tep_item };
> 
> struct rte_flow_action_queue queue_action = { .index = qid };
> 
> struct rte_flow_action_port mark_action = { .index = vni };
> 
> struct rte_flow_action actions[] = {
>                { .type = RTE_FLOW_ACTION_TYPE_DECAP, .conf = &decap_eth },
>                { .type = RTE_FLOW_ACTION_TYPE_DECAP, .conf = &decap_tep },
>                { .type = RTE_FLOW_ACTION_TYPE_MARK, .conf = &mark_action },
>                { .type = RTE_FLOW_ACTION_TYPE_QUEUE, .conf = &queue_action },
>                { .type = RTE_FLOW_ACTION_TYPE_END } };
> 
> /** VERY IMPORTANT NOTE **/
> One of the core concepts of this proposal is that actions which modify the
> packet are defined in the order which they are to be processed. So first
> decap outer ethernet header, then the outer TEP headers.
> I think this is not only logical from a usability point of view, it should also
> simplify the logic required in PMDs to parse the desired actions.
> 
> struct rte_flow *flow =
>                               rte_flow_create(port_id, &attr, pattern, actions, &err);
> 
> The processed packets are delivered to specifed queue with mbuf metadata
> denoting marked flow id and with mbuf ol_flags PKT_RX_TEP_OFFLOAD set.
> 
>     +-----+------+-----+---------+-----+
>     | ETH | IPv4 | TCP | PAYLOAD | CRC |
>     +-----+------+-----+---------+-----+
> 
> 
> Ingress TEP decapsulation switch to port:
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> This is intended to represent how a TEP decapsulation could be configured in
> a switching offload case, it makes an assumption that there is a logical port
> representation for all ports on the hw switch in the DPDK application, but
> similar functionality could be achieved by specifying something like a VF ID of
> the device.
> 
> Like the previous scenario the flows definition for TEP decapsulation actions
> should specify the full outer packet to be matched at a minimum but also
> define the elements of the inner match to match against including masks if
> required.
> 
> struct rte_flow_attr attr = { .ingress = 1 };
> 
> struct rte_flow_item pattern[] = {
>                { .type = RTE_FLOW_ITEM_TYPE_ETH, .spec = &outer_eth_item },
>                { .type = RTE_FLOW_ITEM_TYPE_TEP, .spec = &outer_tep_item,
> .mask = &tep_mask },
>                { .type = RTE_FLOW_ITEM_TYPE_ETH, .spec = &inner_eth_item,
> .mask = &eth_mask }
>                { .type = RTE_FLOW_ITEM_TYPE_IPv4, .spec = &inner_ipv4_item,
> .mask = &ipv4_mask },
>                { .type = RTE_FLOW_ITEM_TYPE_TCP, .spec = &inner_tcp_item,
> .mask = &tcp_mask },
>                { .type = RTE_FLOW_ITEM_TYPE_END } };
> 
> /* Flow Actions Definitions */
> 
> struct rte_flow_action_decap decap_eth = {
>                .type = RTE_FLOW_ITEM_TYPE_ETH,
>                .item = { .src = s_addr, .dst = d_addr, .type = ether_type } };
> 
> struct rte_flow_action_decap decap_tep = {
>                .type = RTE_FLOW_ITEM_TYPE_TEP,
>                .item = &outer_tep_item
> };
> 
> struct rte_flow_action_port port_action = { .index = port_id };
> 
> struct rte_flow_action actions[] = {
>                { .type = RTE_FLOW_ACTION_TYPE_DECAP, .conf = &decap_eth },
>                { .type = RTE_FLOW_ACTION_TYPE_DECAP, .conf = &decap_tep },
>                { .type = RTE_FLOW_ACTION_TYPE_PORT, .conf = &port_action },
>                { .type = RTE_FLOW_ACTION_TYPE_END } };
> 
> struct rte_flow *flow = rte_flow_create(port_id, &attr, pattern, actions,
> &err);
> 
> This action will forward the decapsulated packets to another port of the
> switch fabric but no information will on the tunnel or the fact that the packet
> was decapsulated will be passed with it, thereby enable segregation of the
> infrastructure and
> 
> 
> Egress TEP encapsulation:
> ~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Encapulsation TEP actions require the flow definitions for the source packet
> and then the actions to do on that, this example shows a ipv4/tcp packet
> action.
> 
> Source Packet
> 
>     +-----+------+-----+---------+-----+
>     | ETH | IPv4 | TCP | PAYLOAD | CRC |
>     +-----+------+-----+---------+-----+
> 
> struct rte_flow_attr attr = { .egress = 1 };
> 
> struct rte_flow_item_eth eth_item = { .src = s_addr, .dst = d_addr, .type =
> ether_type }; struct rte_flow_item_ipv4 ipv4_item = { .hdr = { .src_addr =
> src_addr, .dst_addr = dst_addr } }; struct rte_flow_item_udp tcp_item = {
> .hdr = { .src_port = src_port, .dst_port = dst_port } };
> 
> struct rte_flow_item pattern[] = {
>                { .type = RTE_FLOW_ITEM_TYPE_ETH, .spec = &eth_item },
>                { .type = RTE_FLOW_ITEM_TYPE_IPV4, .spec = &ipv4_item },
>                { .type = RTE_FLOW_ITEM_TYPE_TCP, .spec = &tcp_item },
>                { .type = RTE_FLOW_ITEM_TYPE_END } };
> 
> /* Flow Actions Definitions */
> 
> struct rte_flow_action_encap encap_eth = {
>                .type = RTE_FLOW_ITEM_TYPE_ETH,
>                .item = { .src = s_addr, .dst = d_addr, .type = ether_type } };
> 
> struct rte_flow_action_encap encap_tep = {
>                .type = RTE_FLOW_ITEM_TYPE_TEP,
>                .item = { .tep = tep, .id = vni } }; struct rte_flow_action_mark
> port_action = { .index = port_id };
> 
> struct rte_flow_action actions[] = {
>                { .type = RTE_FLOW_ACTION_TYPE_ENCAP, .conf = &encap_tep },
>                { .type = RTE_FLOW_ACTION_TYPE_ENCAP, .conf = &encap_eth },
>                { .type = RTE_FLOW_ACTION_TYPE_PORT, .conf = &port_action },
>                { .type = RTE_FLOW_ACTION_TYPE_END } } struct rte_flow *flow =
> rte_flow_create(port_id, &attr, pattern, actions, &err);
> 
> 
>       encapsulating Outer Hdr
>      /                       \                                      outer crc
>     /                         \                                   /          \
>     +-----+------+-----+-------+-----+------+-----+---------+-----+-----------+
>     | ETH | IPv4 | UDP | VxLAN | ETH | IPv4 | TCP | PAYLOAD | CRC | OUTER
> CRC |
>     +-----+------+-----+-------+-----+------+-----+---------+-----+-----------+
> 
> 
> 
> Chaining multiple modification actions eg IPsec and TEP
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> For example the definition for full hw acceleration for an IPsec ESP/Transport
> SA encapsulated in a vxlan tunnel would look something like:
> 
> struct rte_flow_action actions[] = {
>                { .type = RTE_FLOW_ACTION_TYPE_ENCAP, .conf = &encap_tep },
>                { .type = RTE_FLOW_ACTION_TYPE_SECURITY, .conf = &sec_session
> },
>                { .type = RTE_FLOW_ACTION_TYPE_ENCAP, .conf = &encap_eth },
>                { .type = RTE_FLOW_ACTION_TYPE_END } }
> 
> 1. Source Packet
>                            +-----+------+-----+---------+-----+
>                            | ETH | IPv4 | TCP | PAYLOAD | CRC |
>                            +-----+------+-----+---------+-----+
> 
> 2. First Action - Tunnel Endpoint Encapsulation
> 
>       +------+-----+-------+-----+------+-----+---------+-----+
>       | IPv4 | UDP | VxLAN | ETH | IPv4 | TCP | PAYLOAD | CRC |
>       +------+-----+-------+-----+------+-----+---------+-----+
> 
> 3. Second Action - IPsec ESP/Transport Security Processing
> 
>       +------+-----+-----+-------+-----+------+-----+---------+-----+-------------+
>       | IPv4 | ESP |              ENCRYPTED PAYLOAD                 | ESP TRAILER |
>       +------+-----+-----+-------+-----+------+-----+---------+-----+-------------+
> 
> 4. Third Action - Outer Ethernet Encapsulation
> 
> +-----+------+-----+-----+-------+-----+------+-----+---------+-----+-------------+---
> --------+
> | ETH | IPv4 | ESP |              ENCRYPTED PAYLOAD                 | ESP TRAILER |
> OUTER CRC |
> +-----+------+-----+-----+-------+-----+------+-----+---------+-----+-------------+---
> --------+
> 
> This example demonstrates the importance of making the interoperation of
> actions to be ordered, as in the above example, a security action can be
> defined on both the inner and outer packet by simply placing another
> security action at the beginning of the action list.
> 
> It also demonstrates the rationale for not collapsing the Ethernet into the TEP
> definition as when you have multiple encapsulating actions, all could
> potentially be the place where the Ethernet header needs to be defined.
> 



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