From 13228724c407c290362cfd58151f2e619e953d31 Mon Sep 17 00:00:00 2001 From: Cristian Dumitrescu Date: Mon, 20 Sep 2021 16:01:33 +0100 Subject: [PATCH] examples/pipeline: add learner table example Added the files to illustrate the learner table usage. Signed-off-by: Cristian Dumitrescu --- examples/pipeline/examples/learner.cli | 37 +++++++ examples/pipeline/examples/learner.spec | 127 ++++++++++++++++++++++++ 2 files changed, 164 insertions(+) create mode 100644 examples/pipeline/examples/learner.cli create mode 100644 examples/pipeline/examples/learner.spec diff --git a/examples/pipeline/examples/learner.cli b/examples/pipeline/examples/learner.cli new file mode 100644 index 0000000000..af7792624f --- /dev/null +++ b/examples/pipeline/examples/learner.cli @@ -0,0 +1,37 @@ +; SPDX-License-Identifier: BSD-3-Clause +; Copyright(c) 2020 Intel Corporation + +; +; Customize the LINK parameters to match your setup. +; +mempool MEMPOOL0 buffer 2304 pool 32K cache 256 cpu 0 + +link LINK0 dev 0000:18:00.0 rxq 1 128 MEMPOOL0 txq 1 512 promiscuous on +link LINK1 dev 0000:18:00.1 rxq 1 128 MEMPOOL0 txq 1 512 promiscuous on +link LINK2 dev 0000:3b:00.0 rxq 1 128 MEMPOOL0 txq 1 512 promiscuous on +link LINK3 dev 0000:3b:00.1 rxq 1 128 MEMPOOL0 txq 1 512 promiscuous on + +; +; PIPELINE0 setup. +; +pipeline PIPELINE0 create 0 + +pipeline PIPELINE0 port in 0 link LINK0 rxq 0 bsz 32 +pipeline PIPELINE0 port in 1 link LINK1 rxq 0 bsz 32 +pipeline PIPELINE0 port in 2 link LINK2 rxq 0 bsz 32 +pipeline PIPELINE0 port in 3 link LINK3 rxq 0 bsz 32 + +pipeline PIPELINE0 port out 0 link LINK0 txq 0 bsz 32 +pipeline PIPELINE0 port out 1 link LINK1 txq 0 bsz 32 +pipeline PIPELINE0 port out 2 link LINK2 txq 0 bsz 32 +pipeline PIPELINE0 port out 3 link LINK3 txq 0 bsz 32 +pipeline PIPELINE0 port out 4 sink none + +pipeline PIPELINE0 build ./examples/pipeline/examples/learner.spec + +; +; Pipelines-to-threads mapping. +; +thread 1 pipeline PIPELINE0 enable + +; Once the application has started, the command to get the CLI prompt is: telnet 0.0.0.0 8086 diff --git a/examples/pipeline/examples/learner.spec b/examples/pipeline/examples/learner.spec new file mode 100644 index 0000000000..d635422282 --- /dev/null +++ b/examples/pipeline/examples/learner.spec @@ -0,0 +1,127 @@ +; SPDX-License-Identifier: BSD-3-Clause +; Copyright(c) 2020 Intel Corporation + +; The learner tables are very useful for learning and connection tracking. +; +; As opposed to regular tables, which are read-only for the data plane, the learner tables can be +; updated by the data plane without any control plane intervention. The "learning" process typically +; takes place by having the default action (i.e. the table action which is executed on lookup miss) +; explicitly add to the table with a specific action the key that just missed the lookup operation. +; Each table key expires automatically after a configurable timeout period if not hit during this +; interval. +; +; This example demonstrates a simple connection tracking setup, where the connections are identified +; by the IPv4 destination address. The forwarding action assigned to each new connection gets the +; output port as argument, with the output port of each connection generated by a counter that is +; persistent between packets. On top of the usual table stats, the learner table stats include the +; number of packets with learning related events. + +// +// Headers +// +struct ethernet_h { + bit<48> dst_addr + bit<48> src_addr + bit<16> ethertype +} + +struct ipv4_h { + bit<8> ver_ihl + bit<8> diffserv + bit<16> total_len + bit<16> identification + bit<16> flags_offset + bit<8> ttl + bit<8> protocol + bit<16> hdr_checksum + bit<32> src_addr + bit<32> dst_addr +} + +header ethernet instanceof ethernet_h +header ipv4 instanceof ipv4_h + +// +// Meta-data +// +struct metadata_t { + bit<32> port_in + bit<32> port_out + + // Arguments for the "fwd_action" action. + bit<32> fwd_action_arg_port_out +} + +metadata instanceof metadata_t + +// +// Registers. +// +regarray counter size 1 initval 0 + +// +// Actions +// +struct fwd_action_args_t { + bit<32> port_out +} + +action fwd_action args instanceof fwd_action_args_t { + mov m.port_out t.port_out + return +} + +action learn_action args none { + // Read current counter value into m.fwd_action_arg_port_out. + regrd m.fwd_action_arg_port_out counter 0 + + // Increment the counter. + regadd counter 0 1 + + // Limit the output port values to 0 .. 3. + and m.fwd_action_arg_port_out 3 + + // Add the current lookup key to the table with fwd_action as the key action. The action + // arguments are read from the packet meta-data (the m.fwd_action_arg_port_out field). These + // packet meta-data fields have to be written before the "learn" instruction is invoked. + learn fwd_action + + // Send the current packet to the same output port. + mov m.port_out m.fwd_action_arg_port_out + + return +} + +// +// Tables. +// +learner fwd_table { + key { + h.ipv4.dst_addr + } + + actions { + fwd_action args m.fwd_action_arg_port_out + + learn_action args none + } + + default_action learn_action args none + + size 1048576 + + timeout 120 +} + +// +// Pipeline. +// +apply { + rx m.port_in + extract h.ethernet + extract h.ipv4 + table fwd_table + emit h.ethernet + emit h.ipv4 + tx m.port_out +} -- 2.20.1