15/04/2021 18:41, Bing Zhao: > 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.
You probably mean "flow rule", not "traffic flow". Please make it clear to avoid confusion. > 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. I am not sure this is a feature description for the commit log or an usage explanation for the doc. In any case, please distinguish "ethdev port" and "TCP port" to avoid confusion. > 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 What do you mean by "full advantage"? It is counter-intuitive to re-inject for offloading. Does it improve the performance? > 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: You mean naming is inspired from Linux? > 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 <bi...@nvidia.com> [...] > + /** > + * [META] > + * > + * Matches conntrack state. > + * > + * See struct rte_flow_item_conntrack. Please use @see for hyperlink in doxygen. > + */ > + RTE_FLOW_ITEM_TYPE_CONNTRACK, > }; [...] > +/** > + * The packet is with valid state after conntrack checking. "is with valid state" looks strange. I propose "The packet is valid after conntrack checking." > + */ > +#define RTE_FLOW_CONNTRACK_FLAG_PKT_STATE_VALID (1 << 0) Please use RTE_BIT32(). > +/** > + * 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) "INVAL" is strange. Can we add the missing 2 characters? RTE_FLOW_CONNTRACK_FLAG_PKT_STATE_INVALID On a related note, do we really need the word FLAG? And it is conflicting with the prefix in enum rte_flow_conntrack_tcp_last_index I think RTE_FLOW_CONNTRACK_PKT_STATE_ is a good prefix, long enough. > +/** > + * 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) This one does not have PKT in its name. And it is limiting to HW, while the driver could implement conntrack in SW. I propose RTE_FLOW_CONNTRACK_PKT_DISABLED > +/** > + * 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* s/bit mask/bitmap/ ? RTE_FLOW_CONNTRACK_PKT_STATE_* otherwise it is messed with rte_flow_conntrack_tcp_last_index > + * or a reasonable combination of these bits. > + */ > +struct rte_flow_item_conntrack { > + uint32_t flags; > +}; [...] > + > + /** > + * [META] > + * > + * Enable tracking a TCP connection state. > + * > + * Send packet to HW connection tracking module for examination. Not necessarily HW. No packet is sent. I think you can remove this sentence completely. > + * > + * See struct rte_flow_action_conntrack. @see > + */ > + RTE_FLOW_ACTION_TYPE_CONNTRACK, > }; > > /** > @@ -2875,6 +2940,136 @@ struct rte_flow_action_set_dscp { > */ > struct rte_flow_action_handle; > > +/** > + * 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. */ s/handshark/handshake/ > + 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. */ > +}; Please use RTE_BIT32(). > +/** > + * @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. */ Move all comments on their own line before the struct member. Comment should then start with /** > + uint32_t last_ack_seen:1; > + /**< If set, indicates that there is unacked data of the connection. */ not sure what means "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; Not sure about the word "over" in above definitions. > +}; > + > +/** > + * @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. > + */ As for rte_flow_tcp_dir_param, better to move comments before, on their own line. > + 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. */ > +};
