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Bgpfix

BGP library in Go

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Install / Use

/learn @bgpfix/Bgpfix
About this skill

Quality Score

0/100

Supported Platforms

Universal

README

BGPFix Golang Library

Go Reference

A generic-purpose, high-performance Golang library for bridging the gaps in BGP.

For a stand-alone tool, see bgpipe: BGP pipeline processor.

Summary

BGPFix can "fix" or "extend" BGP sessions in-flight, possibly adding new features or security layers to proprietary BGP speakers (think big router vendors). The project vision is to allow implementing:

Idea

The overall idea is presented below. You don't need to use the whole library, eg. you may stick to the basic BGP message marshal / unmarshal procedures.

bgpfix idea

The above explains the concept of a Pipe: it has two directions used to exchange BGP messages between 2 speakers on the left (L) and right (R) hand side of the picture.

Each Msg sent to the In channel of a particular direction will go through a set of callbacks (think "plugins") configured in the pipe Options. Each callback can read, write, modify, synthesize, or drop messages before they reach the Out channel. In addition to BGP messages, callbacks may emit Events - such as the standard events of the Pipe - which event handlers may subscribe to in the pipe Options.

Example

A basic example on how to establish a BGP session with a router, and print all messages as JSON to stdout:

package main

import (
	"context"
	"flag"
	"fmt"
	"io"
	"net"
	"net/netip"
	"os"

	"github.com/bgpfix/bgpfix/msg"
	"github.com/bgpfix/bgpfix/pipe"
	"github.com/bgpfix/bgpfix/speaker"
)

var (
	opt_active = flag.Bool("active", false, "send OPEN first")
	opt_asn    = flag.Int("asn", 65055, "local ASN number")
	opt_hold   = flag.Int("hold", 60, "local hold timer")
	opt_id     = flag.String("id", "1.1.1.1", "local Id (must be IPv4 address)")
)

func main() {
	// parse flags
	flag.Parse()
	if flag.NArg() == 0 {
		fmt.Printf("usage: bgpfix [OPTIONS] <target:port>\n")
		os.Exit(1)
	}

	// create a Pipe, add callback and event handlers
	p := pipe.NewPipe(context.Background())
	p.OnMsg(print, dir.DIR_LR) // call print() on every message in any direction
	p.OnEvent(event)           // call event() on any pipe event

	// L side: a TCP target, sending to R
	conn, err := net.Dial("tcp", flag.Arg(0)) // assumes a ":179" suffix
	if err != nil {
		panic(err)
	}

	// R side: a local speaker, sending to L
	spk := speaker.NewSpeaker(context.Background())
	spk.Options.Passive = !*opt_active
	spk.Options.LocalASN = *opt_asn
	spk.Options.LocalHoldTime = *opt_hold
	spk.Options.LocalId = netip.MustParseAddr(*opt_id)
	spk.Attach(p, dir.DIR_L)

	// copy from conn -> R
	go func() {
		io.Copy(p.R, conn)
		p.Stop()
	}()

	// copy from L -> conn
	go func() {
		io.Copy(conn, p.L)
		p.Stop()
	}()

	// start and wait till all processing is done
	p.Start()
	p.Wait()
}

func print(m *msg.Msg) bool {
	os.Stdout.Write(m.GetJSON())
	return true
}

func event(ev *pipe.Event) bool {
	switch ev.Type {
	case pipe.EVENT_ESTABLISHED:
		fmt.Printf("session established, capabilities: %s\n", ev.Pipe.Caps.String())
	}
	return true
}

JSON

BGPFix has full, bi-directional BGP to JSON translation support.

For example, below we use bgpipe to connect to the Flowspec version of the great BGP Blackholing project by @LukaszBromirski.

$ bgpipe --log disabled --stdout \
	-- speaker --active --asn 65055 \
	-- connect 85.232.240.180 | jq .
[
  "R",
  1,
  "2024-11-28T13:06:47.574",
  -1,
  "OPEN",
  {
    "bgp": 4,
    "asn": 65055,
    "id": "0.0.0.1",
    "hold": 90,
    "caps": {
      "MP": [
        "IPV4/UNICAST",
        "IPV4/FLOWSPEC",
        "IPV6/UNICAST",
        "IPV6/FLOWSPEC"
      ],
      "ROUTE_REFRESH": true,
      "EXTENDED_MESSAGE": true,
      "AS4": 65055
    }
  },
  {}
]
[
  "L",
  1,
  "2024-11-28T13:06:49.598",
  56,
  "OPEN",
  {
    "bgp": 4,
    "asn": 65055,
    "id": "85.232.240.180",
    "hold": 7200,
    "caps": {
      "MP": [
        "IPV4/FLOWSPEC"
      ],
      "ROUTE_REFRESH": true,
      "EXTENDED_NEXTHOP": [
        "IPV4/UNICAST/IPV6",
        "IPV4/MULTICAST/IPV6",
        "IPV4/MPLS_VPN/IPV6"
      ],
      "AS4": 65055,
      "PRE_ROUTE_REFRESH": true
    }
  },
  {}
]
[
  "L",
  2,
  "2024-11-28T13:06:49.598",
  0,
  "KEEPALIVE",
  null,
  {}
]
[
  "R",
  2,
  "2024-11-28T13:06:49.598",
  0,
  "KEEPALIVE",
  null,
  {}
]
[
  "L",
  3,
  "2024-11-28T13:06:54.622",
  316,
  "UPDATE",
  {
    "attrs": {
      "ORIGIN": {
        "flags": "T",
        "value": "IGP"
      },
      "ASPATH": {
        "flags": "T",
        "value": []
      },
      "LOCALPREF": {
        "flags": "T",
        "value": 100
      },
      "ORIGINATOR": {
        "flags": "O",
        "value": "85.232.240.170"
      },
      "CLUSTER_LIST": {
        "flags": "O",
        "value": [
          "85.232.240.180"
        ]
      },
      "MP_REACH": {
        "flags": "OX",
        "value": {
          "af": "IPV4/FLOWSPEC",
          "nexthop": "192.0.2.1",
          "rules": [
            {
              "SRC": "2.59.255.53/32",
              "PROTO": [
                {
                  "op": "==",
                  "val": 6
                }
              ],
              "PORT_DST": [
                {
                  "op": "==",
                  "val": 25
                }
              ]
            },
            {
              "SRC": "5.29.8.251/32",
              "PROTO": [
                {
                  "op": "==",
                  "val": 6
                }
              ],
              "PORT_DST": [
                {
                  "op": "==",
                  "val": 25
                }
              ]
            },
// *** ... cut many, many lines ... ***
            {
              "SRC": "220.158.197.0/24",
              "PROTO": [
                {
                  "op": "==",
                  "val": 6
                }
              ],
              "PORT_DST": [
                {
                  "op": "==",
                  "val": 25
                }
              ]
            }
          ]
        }
      },
      "EXT_COMMUNITY": {
        "flags": "OT",
        "value": [
          {
            "type": "FLOW_RATE_BYTES",
            "value": 0
          }
        ]
      }
    }
  },
  {}
]
[
  "L",
  9,
  "2024-11-28T13:06:54.708",
  10,
  "UPDATE",
  {
    "attrs": {
      "MP_UNREACH": {
        "flags": "O",
        "value": {
          "af": "IPV4/FLOWSPEC",
          "rules": []
        }
      }
    }
  },
  {}
]
^C

BGP features

RFCs:

bgpfix

View profile

View on GitHub
GitHub Stars33
CategoryProduct
Updated24d ago
Forks5
bgpfix/bgpfix

Languages

Go

Security Score

90/100

Audited on Mar 11, 2026

No findings