networking/devlink/devlink-dpipe.rst

1 .. SPDX-License-Identifier: GPL-2.0
12 ``devlink-dpipe`` provides a standardized way to provide visibility into the
34 Level Path Compression trie (LPC-trie) in hardware.
45 The ``devlink-dpipe`` interface closes this gap. The hardware's pipeline is
46 modeled as a graph of match/action tables. Each table represents a specific
50 configuration, but the ``devlink-dpipe`` interface uses it for visibility
52 ``devlink-dpipe`` should change according to the changes done by the
58 different priorities and different lookup keys. On the other hand hardware
59 TCAM regions have a predefined lookup key. Offloading the TC filter rules
74 the packet. A ``table`` describes hardware blocks. An ``entry`` describes
75 the actual content of a specific table.
84 ``devlink-dpipe`` generally is not intended for configuration. The exception
85 is hardware counting for a specific table.
90   * ``table_get``: Receive a table's description.
92   * ``entries_get``: Receive a table's current entries.
93   * ``counters_set``: Enable or disable counters on a table.
95 Table  section in Model
96 -----
98 The driver should implement the following operations for each table:
102   * ``entries_dump``: Dump the actual content of the table.
107 ------------
109 In a similar way to P4 headers and fields are used to describe a table's
113 and should be defined in the driver. Additionally, each driver-specific
114 devlink documentation file should document the driver-specific ``dpipe``
119 be directly mapped to the net device ifindex. FIB table indexes used by
121 internal routing table indexes.
124 -----
140 ------
151 -----
153 Entries of a specific table can be dumped on demand. Each eentry is
163 the pipeline. The table sizes in the following examples are not real
167 ---
170 table contains routes with the same prefix length. The root of the list is
172 table. The depth of the search will affect the data path latency.
176 host table for directly connected routes, or adjacency table for next-hops.
181     table lpm_prefix_16 {
195 ----------
197 In the case of local routes the LPM lookup already resolves the egress
199 host table is a hash table combining the output interface id with
204     table local_host {
213 ---------
215 In case of remote routes this table does the ECMP. The LPM lookup results in
216 ECMP group size and index that serves as a global offset into this table.
223     table adjacency {
234 ----
237 tables this table does multiple operations like TTL decrease and MTU check.
243     table erif {