[dpdk-dev] [PATCH] ethdev: introduce conntrack flow action and item

[Bing Zhao <bingz@nvidia.com>]

This commit introduced the conntrack action and item.

Usually the HW offloading is stateless. For some stateful offloading
like a TCP connection, HW module will help provide the ability of a
full offloading w/o SW participation after the connection was
established.

The basic usage is that in the first flow the application should add
the conntrack action and in the following flow(s) the application
should use the conntrack item to match on the result.

A TCP connection has two directions traffic. To set a conntrack
action context correctly, information from packets of both directions
are required.

The conntrack action should be created on one port and supply the
peer port as a parameter to the action. After context creating, it
could only be used between the ports (dual-port mode) or a single
port. The application should modify the action via the API
"action_handle_update" only when before using it to create a flow
with opposite direction. This will help the driver to recognize the
direction of the flow to be created, especially in single port mode.
The traffic from both directions will go through the same port if
the application works as an "forwarding engine" but not a end point.
There is no need to call the update interface if the subsequent flows
have nothing to be changed.

Query will be supported via action_ctx_query interface, about the
current packets information and connection status. Tha fields
query capabilities depends on the HW.

For the packets received during the conntrack setup, it is suggested
to re-inject the packets in order to take full advantage of the
conntrack. Only the valid packets should pass the conntrack, packets
with invalid TCP information, like out of window, or with invalid
header, like malformed, should not pass.

Naming and definition:
https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/netfilter/nf_conntrack_tcp.h
https://elixir.bootlin.com/linux/latest/source/net/netfilter/nf_conntrack_proto_tcp.c

Other reference:
https://www.usenix.org/legacy/events/sec01/invitedtalks/rooij.pdf

Signed-off-by: Bing Zhao <bingz@nvidia.com>
---
 lib/librte_ethdev/rte_flow.h | 195 +++++++++++++++++++++++++++++++++++
 1 file changed, 195 insertions(+)

diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
index 6cc57136ac..d506377f7e 100644
--- a/lib/librte_ethdev/rte_flow.h
+++ b/lib/librte_ethdev/rte_flow.h
@@ -551,6 +551,15 @@ enum rte_flow_item_type {
 	 * See struct rte_flow_item_geneve_opt
 	 */
 	RTE_FLOW_ITEM_TYPE_GENEVE_OPT,
+
+	/**
+	 * [META]
+	 *
+	 * Matches conntrack state.
+	 *
+	 * See struct rte_flow_item_conntrack.
+	 */
+	RTE_FLOW_ITEM_TYPE_CONNTRACK,
 };
 
 /**
@@ -1685,6 +1694,51 @@ rte_flow_item_geneve_opt_mask = {
 };
 #endif
 
+/**
+ * The packet is with valid state after conntrack checking.
+ */
+#define RTE_FLOW_CONNTRACK_FLAG_PKT_STATE_VALID (1 << 0)
+/**
+ * The state of the connection was changed.
+ */
+#define RTE_FLOW_CONNTRACK_FLAG_PKT_STATE_CHANGED (1 << 1)
+/**
+ * Error is detected on this packet for this connection and
+ * an invalid state is set.
+ */
+#define RTE_FLOW_CONNTRACK_FLAG_PKT_STATE_INVAL (1 << 2)
+/**
+ * The HW connection tracking module is disabled.
+ * It can be due to application command or an invalid state.
+ */
+#define RTE_FLOW_CONNTRACK_FLAG_HW_DISABLED (1 << 3)
+/**
+ * The packet contains some bad field(s) and cannot continue
+ * with the conntrack module checking.
+ */
+#define RTE_FLOW_CONNTRACK_FLAG_PKT_BAD (1 << 4)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this structure may change without prior notice
+ *
+ * RTE_FLOW_ITEM_TYPE_CONNTRACK
+ *
+ * Matches the state of a packet after it passed the connection tracking
+ * examination. The state is a bit mask of one RTE_FLOW_CONNTRACK_FLAG*
+ * or a reasonable combination of these bits.
+ */
+struct rte_flow_item_conntrack {
+	uint32_t flags;
+};
+
+/** Default mask for RTE_FLOW_ITEM_TYPE_CONNTRACK. */
+#ifndef __cplusplus
+static const struct rte_flow_item_conntrack rte_flow_item_conntrack_mask = {
+	.flags = 0xffffffff,
+};
+#endif
+
 /**
  * Matching pattern item definition.
  *
@@ -2267,6 +2321,17 @@ enum rte_flow_action_type {
 	 * See struct rte_flow_action_modify_field.
 	 */
 	RTE_FLOW_ACTION_TYPE_MODIFY_FIELD,
+
+	/**
+	 * [META]
+	 *
+	 * Enable tracking a TCP connection state.
+	 *
+	 * Send packet to HW connection tracking module for examination.
+	 *
+	 * See struct rte_flow_action_conntrack.
+	 */
+	RTE_FLOW_ACTION_TYPE_CONNTRACK,
 };
 
 /**
@@ -2859,6 +2924,136 @@ struct rte_flow_action_set_dscp {
  */
 struct rte_flow_shared_action;
 
+/**
+ * The state of a TCP connection.
+ */
+enum rte_flow_conntrack_state {
+	/**< SYN-ACK packet was seen. */
+	RTE_FLOW_CONNTRACK_STATE_SYN_RECV,
+	/**< 3-way handshark was done. */
+	RTE_FLOW_CONNTRACK_STATE_ESTABLISHED,
+	/**< First FIN packet was received to close the connection. */
+	RTE_FLOW_CONNTRACK_STATE_FIN_WAIT,
+	/**< First FIN was ACKed. */
+	RTE_FLOW_CONNTRACK_STATE_CLOSE_WAIT,
+	/**< Second FIN was received, waiting for the last ACK. */
+	RTE_FLOW_CONNTRACK_STATE_LAST_ACK,
+	/**< Second FIN was ACKed, connection was closed. */
+	RTE_FLOW_CONNTRACK_STATE_TIME_WAIT,
+};
+
+/**
+ * The last passed TCP packet flags of a connection.
+ */
+enum rte_flow_conntrack_tcp_last_index {
+	RTE_FLOW_CONNTRACK_FLAG_NONE = 0, /**< No Flag. */
+	RTE_FLOW_CONNTRACK_FLAG_SYN = (1 << 0), /**< With SYN flag. */
+	RTE_FLOW_CONNTRACK_FLAG_SYNACK = (1 << 1), /**< With SYN+ACK flag. */
+	RTE_FLOW_CONNTRACK_FLAG_FIN = (1 << 2), /**< With FIN flag. */
+	RTE_FLOW_CONNTRACK_FLAG_ACK = (1 << 3), /**< With ACK flag. */
+	RTE_FLOW_CONNTRACK_FLAG_RST = (1 << 4), /**< With RST flag. */
+};
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this structure may change without prior notice
+ *
+ * Configuration parameters for each direction of a TCP connection.
+ */
+struct rte_flow_tcp_dir_param {
+	uint32_t scale:4; /**< TCP window scaling factor, 0xF to disable. */
+	uint32_t close_initiated:1; /**< The FIN was sent by this direction. */
+	/**< An ACK packet has been received by this side. */
+	uint32_t last_ack_seen:1;
+	/**< If set, indicates that there is unacked data of the connection. */
+	uint32_t data_unacked:1;
+	/**< Maximal value of sequence + payload length over sent
+	 * packets (next ACK from the opposite direction).
+	 */
+	uint32_t sent_end;
+	/**< Maximal value of (ACK + window size) over received packet + length
+	 * over sent packet (maximal sequence could be sent).
+	 */
+	uint32_t reply_end;
+	/**< Maximal value of actual window size over sent packets. */
+	uint32_t max_win;
+	/**< Maximal value of ACK over sent packets. */
+	uint32_t max_ack;
+};
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this structure may change without prior notice
+ *
+ * RTE_FLOW_ACTION_TYPE_CONNTRACK
+ *
+ * Configuration and initial state for the connection tracking module.
+ * This structure could be used for both setting and query.
+ */
+struct rte_flow_action_conntrack {
+	uint16_t peer_port; /**< The peer port number, can be the same port. */
+	/**< Direction of this connection when creating a flow, the value only
+	 * affects the subsequent flows creation.
+	 */
+	uint32_t is_original_dir:1;
+	/**< Enable / disable the conntrack HW module. When disabled, the
+	 * result will always be RTE_FLOW_CONNTRACK_FLAG_DISABLED.
+	 * In this state the HW will act as passthrough.
+	 * It only affects this conntrack object in the HW without any effect
+	 * to the other objects.
+	 */
+	uint32_t enable:1;
+	/**< At least one ack was seen, after the connection was established. */
+	uint32_t live_connection:1;
+	/**< Enable selective ACK on this connection. */
+	uint32_t selective_ack:1;
+	/**< A challenge ack has passed. */
+	uint32_t challenge_ack_passed:1;
+	/**< 1: The last packet is seen that comes from the original direction.
+	 * 0: From the reply direction.
+	 */
+	uint32_t last_direction:1;
+	/**< No TCP check will be done except the state change. */
+	uint32_t liberal_mode:1;
+	/**< The current state of the connection. */
+	enum rte_flow_conntrack_state state;
+	/**< Scaling factor for maximal allowed ACK window. */
+	uint8_t max_ack_window;
+	/**< Maximal allowed number of retransmission times. */
+	uint8_t retransmission_limit;
+	/**< TCP parameters of the original direction. */
+	struct rte_flow_tcp_dir_param original_dir;
+	/**< TCP parameters of the reply direction. */
+	struct rte_flow_tcp_dir_param reply_dir;
+	/**< The window value of the last packet passed this conntrack. */
+	uint16_t last_window;
+	enum rte_flow_conntrack_tcp_last_index last_index;
+	/**< The sequence of the last packet passed this conntrack. */
+	uint32_t last_seq;
+	/**< The acknowledgement of the last packet passed this conntrack. */
+	uint32_t last_ack;
+	/**< The total value ACK + payload length of the last packet passed
+	 * this conntrack.
+	 */
+	uint32_t last_end;
+};
+
+/**
+ * RTE_FLOW_ACTION_TYPE_CONNTRACK
+ *
+ * Wrapper structure for the context update interface.
+ * Ports cannot support updating, and the only valid solution is to
+ * destroy the old context and create a new one instead.
+ */
+struct rte_flow_modify_conntrack {
+	/**< New connection tracking parameters to be updated. */
+	struct rte_flow_action_conntrack new_ct;
+	uint32_t direction:1; /**< The direction field will be updated. */
+	/**< All the other fields except direction will be updated. */
+	uint32_t state:1;
+	uint32_t reserved:30; /**< Reserved bits for the future usage. */
+};
+
 /**
  * Field IDs for MODIFY_FIELD action.
  */
-- 
2.30.0.windows.2