P4 DPDK Target Components
=========================
p4-dpdk-target repo contains the P4-DPDK target specific code that supports
the target independent Table Driven Interface (TDI).
p4-dpdk-target works in conjunction with following repos:
Table Driven Interface:
(https://github.com/p4lang/tdi)
TDI (Table Driven Interface) provides the target independent frontend
interface while p4-dpdk-target provides the target dependent backend
for DPDK SWX pipeline.
p4-dpdk-target submodules tdi repo. p4-dpdk-target isn't currently
defined in p4-dpdk-target/include/bf_rt directory.
DPDK SWX Pipeline:
(https://github.com/DPDK/dpdk/blob/main/lib/pipeline)
P4 DPDK SWX pipeline implements the P4 pipeline in a DPDK software switch.
The software switch is driven by artifacts generated by the P4 compiler
for P4 DPDK SWX pipeline.
p4-dpdk-target submodules dpdk repo to build P4 DPDK pipeline.
Note about DPDK Patches (p4-dpdk-target/src/lld/dpdk/patch):
DPDK patches 0001-pipeline-updated-instruction-label-check.patch and
0001-add-ctl-wrapper-api.patch are a temporary solution and will be
removed. The fixes are being worked upon and will be committed soon.
P4 Compiler DPDK Backend:
(https://github.com/p4lang/p4c/tree/main/backends/dpdk)
P4C DPDK backend creates the artifact files used by p4-dpdk-target
and DPDK SWX pipeline.
p4-dpdk-target uses bfrt.json to define the program independent frontend
bf_rt interface.
context.json is used to map the P4 runtime info to the P4 DPDK target
specific info.
The P4 DPDK spec file from P4C DPDK, which is used by DPDK SWX pipeline
to setup the software pipeline, is also loaded through p4-dpdk-target.
Target backend utilities:
(https://github.com/p4lang/target-utils)
(https://github.com/p4lang/target-syslibs)
p4-dpdk-target utilizes the libraries built through target-utils and
target-syslibs libraries. p4-dpdk-target uses these libraries
in the install directory.
P4-OVS:
(https://github.com/ipdk-io/ovs)
The remote control plane interfaces like P4 Runtime and OpenConfig are
supported through P4-OVS. P4-OVS maps these remote protocol messages
and maps them to TDI interface. (Currently, it maps them to the interim
bf_rt interface).
Code Organization
=================
The drivers are P4 independent. At the time of device initialization,
they take artifacts associated with P4 as inputs.
p4-dpdk-target is organized as follows
include/
Header files associated with various driver modules
bf_rt:
bf_rt defines the interim frontend interface till TDI interface is
supported.
src/
Driver source files. Largely they are categorized into these submodules.
pipe_mgr:
P4 Pipeline Mgmt API (e.g. tables, actions, stats, meters)
port_mgr:
Port Mgmt API
lld:
Low Level Driver (e.g. DPDK library)
dvm:
Device Mgmt (e.g. device/port instantiation, HA sequences)
bf_rt:
P4 program independent and object driven implementation.
bf_pal:
Platform related code to support device and port management.
ctx_json:
Utility used for parsing cJSON structures in context JSON.
bf_switchd/
Reference implementation of application to exercise the drivers.
third-party/tdi
Target independent frontend interface. (To be supported in future.)
tools/
Scripts to help dependencies installation, ports setup and executing.
dependencies/
Python requirements files used by the driver.
doc/
Files used for doxygen.
Building and installing
=======================
The building of drivers produces a set of libraries that need to be
loaded (or linked to) the application.
Note: SDE is the top level directory with this p4-dpdk-target, syslibs and utils repo cloned in next step
#Create install directory under SDE
sudo -s
mkdir install
#Set environment variables
To set environment variables for SDE, see below :-
cd p4-dpdk-target/tools/setup
source p4sde_env_setup.sh <path to SDE directory>
Ensure SDE, SDE_INSTALL and LD_LIBRARY_PATH environment variables are set correctly
# Install dependent packages
To Install the dependencies for p4-driver on the platform Fedora 33, see below:-
Note:- Make sure that your yum repository proxy and environment proxies are set properly and you have sudo access.
pip3 install distro (dependency)
cd p4-dpdk-target/tools/setup
python3 install_dep.py
# Building P4 DPDK target
cd $SDE/p4-dpdk-target
git submodule update --init --recursive --force
./autogen.sh
./configure --prefix=$SDE_INSTALL
make -j
make install
Artifacts installed
===================
Here're the artifacts that get installed for p4-driver.
Build artifacts:
header files for driver API to $SDE_INSTALL/include/
libdriver.[a,la,so] to $SDE_INSTALL/lib/
driver library to manage the device
bf_switchd to $SDE_INSTALL/bin
reference implementation to exercise driver API
Running Reference App
======================
bf_switchd is a reference application that can be configured through a debug CLI.
# Running of bf_switchd
cd $SDE_INSTALL/bin
./bf_switchd --install-dir $SDE_INSTALL --conf-file $SDE_INSTALL/share/dpdk/<P4 program name>/<P4 program name>.conf --init-mode=cold --status-port 7777
# Config file used by bf_switchd
bf_switchd uses a config file to initialize. Following are some of the key fields:
bfrt-config: Use file generated from the P4C DPDK for P4 pipeline definition.
port-config: Optional file to describe initial ports topology.
context: Use file generated from the P4C DPDK to map P4 to P4 DPDK.
config: Use file generated from the P4C DPDK to setup P4 DPDK pipeline.
{
"chip_list": [
{
"id": "asic-0",
"chip_family": "dpdk",
"instance": 0,
}
],
"instance": 0,
"p4_devices": [
{
"device-id": 0,
"p4_programs": [
{
"program-name": "<P4 program name>",
"cpu_numa_node": "0",
"bfrt-config": "share/dpdk/<P4 program name>/bf-rt.json",
"port-config": "share/dpdk/<P4 program name>/ports_topology.json",
"eal-args": "dummy -n 4 -c 3",
"p4_pipelines": [
{
"p4_pipeline_name": "pipe",
"context": "share/dpdk/<P4 program name>/pipe/context.json",
"config": "share/dpdk/<P4 program name>/pipe/<P4 program name>.spec",
"path": "share/dpdk/<P4 program name>"
}
]
}
],
}
]
}
# CLI interface
Once bf_switchd starts running, bfshell is available.
bfshell> bfrt_python
bfrt.<P4 program>.enable
pipe = bfrt.<P4 program>.pipe.ingress
from netaddr import IPAddress
pipe.<P4 table>.<P4 action>(<action parameters>)
eg) pipe.ipv4_lpm.add_with_send(dst_addr=IPAddress('192.168.2.0'),dst_addr_p_length=24, port=1)