rte_flow_attr(3)

📦 version 26.03, in nixos 26.05, nixpkgs unstable

🌈 NAME

rte_flow_attr — the flow rule attributes struct, straight out of the Library Functions Manual, bestie. This is the page for the C struct that tells your flow rule where it lives, how it behaves, and what direction it’s serving. 💅

✨ SYNOPSIS

#include <rte_flow.h>

🎀 Data Fields

  • uint32_t group
  • uint32_t priority
  • uint32_t ingress:1
  • uint32_t egress:1
  • uint32_t transfer:1
  • uint32_t reserved:29

💖 Detailed Description

Flow rule attributes. That’s the whole main-character energy of this struct. 👑

Priorities are set per rule inside groups. Lower values mean higher priority, and the highest priority for a flow rule is 0, so if a flow matches more than one rule, the rule with the lowest priority value will always be matched. Slay, but also pay attention. ✨

Although it’s optional, applications are encouraged to group similar rules as much as possible. Why? So you can fully take advantage of hardware capabilities — think optimized matching — and work around limitations, like a single pattern type possibly being allowed in a given group. Applications should be aware that groups are not linked by default, and that they must be explicitly linked by the application using the JUMP action. No cap.

Priority levels are arbitrary and up to the application. They do not need to be contiguous, and they don’t need to start from 0. However, the maximum number varies between devices and may be affected by existing flow rules. 🌀

If a packet is matched by several rules of a given group for a given priority level, the outcome is undefined. It can take any path, may be duplicated, or even cause unrecoverable errors. That is not a drill, bestie. 💀

Note that support for more than a single group and priority level is not guaranteed.

At vNIC / ethdev level, flow rules can apply to inbound and / or outbound traffic — ingress / egress — with respect to the vNIC / ethdev in question. At embedded switch level, flow rules apply to all traffic seen by it unless fitting meta items are used to set concrete traffic source(s). 🦋

Several pattern items and actions are valid and can be used in both directions. Those valid for only one direction are described as such.

At least one direction must be specified. 🫶

Specifying both directions at once for a given rule is not recommended, but may be valid in a few cases.

Definition at line 89 of file rte_flow.h.

🧚 Field Documentation

🍓 uint32_t group

A group is a superset of multiple rules. The default group is 0 and is processed for all packets. Rules in other groups are processed only if the group is chained by a jump action from a previously matched rule. It means the group hierarchy is made by the flow rules, and the group 0 is the hierarchy root. Note there is no automatic dead loop protection. 😭

See also: rte_flow_action_jump.

Definition at line 100 of file rte_flow.h.

🍓 uint32_t priority

Rule priority level within group.

Definition at line 101 of file rte_flow.h.

🍓 uint32_t ingress

The rule in question applies to ingress traffic (non-"transfer").

Definition at line 105 of file rte_flow.h.

🍓 uint32_t egress

The rule in question applies to egress traffic (non-"transfer").

Definition at line 109 of file rte_flow.h.

🍓 uint32_t transfer

Instead of simply matching the properties of traffic as it would appear on a given DPDK port ID, enabling this attribute transfers a flow rule to the lowest possible level of any device endpoints found in the pattern.

When supported, this effectively enables an application to re-route traffic not necessarily intended for it — e.g. coming from or addressed to different physical ports, VFs or applications — at the device level. That’s lowkey wild, but it’s in the manual. 🌈

The application should match traffic originating from precise locations. See items PORT_REPRESENTOR and REPRESENTED_PORT.

Managing "transfer" flows requires that the user communicate them through a suitable port.

See also: rte_flow_pick_transfer_proxy().

Definition at line 127 of file rte_flow.h.

🍓 uint32_t reserved

Reserved, must be zero.

Definition at line 128 of file rte_flow.h.

👑 Author

Generated automatically by Doxygen for DPDK from the source code.

💖 That’s the whole page, bestie. Footer vibe check: DPDK, Version 26.03.0, rte_flow_attr(3) — and that’s the manual page, periodt. 🫶🎀

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