BGP++

BGP++ is Meta's C++ implementation of the Border Gateway Protocol. It supports Meta's Data Center and Express Backbone networks and can be used as a standalone routing daemon or as a collection of BGP libraries.

This repository provides two mutually exclusive build variants:

• DC: Data Center integration using the FBOSS Agent and FSDB.
• BB: Express Backbone integration using FibEbb, Open/R, and Linux netlink.

Note: The daemons require platform FIB services and a valid BGP configuration at runtime. Building this repository does not produce a complete switch image or a turnkey router deployment.

Build variants

Variant	CMake value	FBOSS profile	CMake target	Installed binary	Platform integration
DC	dc	fsdb_client	bgp_bin	sbin/bgp	FBOSS Agent and FSDB
BB	bb	exported_libraries	bgp_bb_bin	sbin/bgp_bb	FibEbb, Open/R, and netlink

dc is the default CMake variant. GitHub CI always sets the variant explicitly.

Only one variant is configured in each CMake tree. Use separate scratch directories for DC and BB builds.

Requirements

The supported OSS build uses getdeps.py, which downloads and builds BGP++ and its dependencies.

The build requires:

• Linux. GitHub CI runs on Ubuntu.
• Python 3.
• Git.
• A C++20-capable compiler. The dependency manifest includes GCC 12.
• CMake 3.19 or newer when configuring the dependency profiles directly.
• Permission to install system packages when using --allow-system-packages.
• Sufficient memory and disk space to build FBOSS, Open/R, Folly, FBThrift, and their dependencies.

GitHub CI uses 18 parallel jobs on a 32-core runner. Use a lower value on machines with less memory.

Clone the repository

git clone https://github.com/facebook/BGP.git
cd BGP

# Adjust for the available CPU and memory.
JOBS="${JOBS:-8}"

Scratch directories

Use a separate scratch directory outside the Git checkout for each variant:

Variant	Example
DC	/tmp/${USER}-bgp-build-dc
BB	/tmp/${USER}-bgp-build-bb

Do not use paths inside the repository, such as ./build-output or ./.getdeps, and do not share one scratch directory between DC and BB.

There are two reasons:

1. getdeps.py applies dependency patches relative to the enclosing Git repository. An in-repository scratch path can make patches resolve against the BGP checkout and fail with errors such as No such file or directory.
2. DC and BB use different BGP_BUILD_VARIANT and FBOSS_BUILD_PROFILE values. Reusing one scratch directory can retain dependency configuration from the other variant and cause incorrect configure or link results.

When switching variants, use the matching existing scratch directory or create a new one.

Build the DC variant

The DC build uses the FBOSS fsdb_client profile and produces bgp.

DC_SCRATCH="${DC_SCRATCH:-/tmp/${USER}-bgp-build-dc}"

sudo env \
  BUILD_SAI_FAKE=1 \
  FBOSS_BUILD_PROFILE=fsdb_client \
  python3 build/fbcode_builder/getdeps.py \
  --allow-system-packages \
  --scratch-path "$DC_SCRATCH" \
  build \
  --extra-cmake-defines='{"BGP_BUILD_VARIANT":"dc"}' \
  --src-dir=. \
  --num-jobs "${JOBS:-8}" \
  bgp

BUILD_SAI_FAKE=1 builds the FBOSS dependency without a vendor SAI SDK. --src-dir=. ensures that the current BGP checkout is built.

Build the BB variant

The BB build uses the smaller FBOSS exported_libraries profile and produces bgp_bb.

BB_SCRATCH="${BB_SCRATCH:-/tmp/${USER}-bgp-build-bb}"

sudo env \
  BUILD_SAI_FAKE=1 \
  FBOSS_BUILD_PROFILE=exported_libraries \
  python3 build/fbcode_builder/getdeps.py \
  --allow-system-packages \
  --scratch-path "$BB_SCRATCH" \
  build \
  --extra-cmake-defines='{"BGP_BUILD_VARIANT":"bb"}' \
  --src-dir=. \
  --num-jobs "${JOBS:-8}" \
  bgp

The BB profile builds only these FBOSS libraries and their dependencies:

• nodebase
• radix_tree
• exponential_back_off
• log_thrift_call
• alert_logger

The BGP manifest selects Open/R's exported_libraries profile automatically.

Run tests

Tests must use the same variant, FBOSS profile, scratch directory, and build type as the corresponding build.

DC tests

DC_SCRATCH="${DC_SCRATCH:-/tmp/${USER}-bgp-build-dc}"

sudo env \
  BUILD_SAI_FAKE=1 \
  FBOSS_BUILD_PROFILE=fsdb_client \
  python3 build/fbcode_builder/getdeps.py \
  --allow-system-packages \
  --scratch-path "$DC_SCRATCH" \
  test \
  --extra-cmake-defines='{"BGP_BUILD_VARIANT":"dc"}' \
  --src-dir=. \
  --num-jobs "${JOBS:-8}" \
  bgp

BB tests

BB_SCRATCH="${BB_SCRATCH:-/tmp/${USER}-bgp-build-bb}"

sudo env \
  BUILD_SAI_FAKE=1 \
  FBOSS_BUILD_PROFILE=exported_libraries \
  python3 build/fbcode_builder/getdeps.py \
  --allow-system-packages \
  --scratch-path "$BB_SCRATCH" \
  test \
  --extra-cmake-defines='{"BGP_BUILD_VARIANT":"bb"}' \
  --src-dir=. \
  --num-jobs "${JOBS:-8}" \
  bgp

Locate the installed binaries

Use show-inst-dir with the same scratch directory, CMake variant, and privilege as the corresponding build.

DC

DC_SCRATCH="${DC_SCRATCH:-/tmp/${USER}-bgp-build-dc}"

DC_INSTALL_DIR="$(
  sudo env \
  BUILD_SAI_FAKE=1 \
  FBOSS_BUILD_PROFILE=fsdb_client \
  python3 build/fbcode_builder/getdeps.py \
  --scratch-path "$DC_SCRATCH" \
  show-inst-dir \
  --extra-cmake-defines='{"BGP_BUILD_VARIANT":"dc"}' \
  --src-dir=. \
  bgp
)"

sudo "$DC_INSTALL_DIR/sbin/bgp" --version

BB

BB_SCRATCH="${BB_SCRATCH:-/tmp/${USER}-bgp-build-bb}"

BB_INSTALL_DIR="$(
  sudo env \
  BUILD_SAI_FAKE=1 \
  FBOSS_BUILD_PROFILE=exported_libraries \
  python3 build/fbcode_builder/getdeps.py \
  --scratch-path "$BB_SCRATCH" \
  show-inst-dir \
  --extra-cmake-defines='{"BGP_BUILD_VARIANT":"bb"}' \
  --src-dir=. \
  bgp
)"

sudo "$BB_INSTALL_DIR/sbin/bgp_bb" --version

getdeps.py installs the selected daemon under sbin/, generated and public headers under include/, and reusable static libraries under lib/.

Build only the daemon

The commands above build the complete selected variant, including its test targets. For a daemon-only build, add these options after the build subcommand:

Variant	Additional options
DC	--no-tests --cmake-target bgp_bin
BB	--no-tests --cmake-target bgp_bb_bin

Rerun the complete build without --no-tests before invoking getdeps.py test.

Build types

getdeps.py supports:

• Debug
• RelWithDebInfo — default
• MinSizeRel
• Release

Pass the same value to every build, test, and path-query command:

--build-type Debug

Runtime integration

Both daemons accept:

• --config=<path> for the BGP configuration.
• --policy=<path> for an optional separate policy configuration.
• --help to list all registered command-line flags.
• --version for build information.

The main configuration schema is configerator/structs/neteng/fboss/bgp/bgp_config.thrift. Policy schemas are under configerator/structs/neteng/bgp_policy/thrift/.

A test-only standalone configuration is available at neteng/fboss/bgp/cpp/tests/sample_configs/stand_alone_conf.json. It is a test fixture, not a production deployment template.

During normal startup:

• bgp waits for the FBOSS Agent FIB service.
• bgp_bb waits for both FibEbb and the Open/R FIB agent.
• --platform=dev skips the platform-readiness wait for development, but does not provide the missing FIB services.

Repository layout

The paths below are relative to the GitHub repository root.

Path	Purpose
CMakeLists.txt	Top-level CMake entry point. It selects BGP_BUILD_VARIANT=dc|bb.
cmake/	Defines the shared, DC, and BB CMake targets.
neteng/fboss/bgp/	Contains the BGP source, Thrift services, tests, and sample configurations.
configerator/	Contains the public BGP configuration and routing-policy Thrift schemas.
common/	Contains the shared network and FB303 headers and schemas used by BGP.
build/fbcode_builder/	Provides getdeps.py, dependency manifests, and shared CMake helpers.
.github/workflows/	Contains the GitHub Actions workflow.
CONTRIBUTING.md	Describes how to contribute to the repository.
CODE_OF_CONDUCT.md	Defines the project code of conduct.
LICENSE	Contains the Apache License 2.0 text.