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BGPFix Golang Library

Go Reference

WORK IN PROGRESS PREVIEW 03/2024

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

See the bgpipe BGP reverse proxy for a CLI tool.

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

If you're interested in bgpfix, you might also want to see:

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, msg.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, msg.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) {
	fmt.Printf("%s\n", m.GetJSON())
}

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

JSON

bgpfix has full, bidirectional BGP to JSON translation support.

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

pjf@pjf:~/bgp2json$ ./bgp2json -active -asn 65055 85.232.240.180:179 | jq .
[
  "2023-08-18T11:33:41.298",
  1,
  "L",
  "OPEN",
  -1,
  {
	"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
	}
  }
]
[
  "2023-08-18T11:33:41.324",
  1,
  "R",
  "OPEN",
  56,
  {
	"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
	}
  }
]
[
  "2023-08-18T11:33:41.325",
  2,
  "L",
  "KEEPALIVE",
  0,
  null
]
[
  "2023-08-18T11:33:41.348",
  2,
  "R",
  "KEEPALIVE",
  0,
  null
]
[
  "2023-08-18T11:33:46.352",
  3,
  "R",
  "UPDATE",
  316,
  {
	"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
				}
			  ]
			},
			/*** ... cut many lines ... ***/
		  ]
		}
	  },
	  "EXT_COMMUNITY": {
		"flags": "OT",
		"value": [
		  {
			"type": "FLOW_RATE_BYTES",
			"value": 0
		  }
		]
	  }
	}
  }
]
[
  "2023-08-18T11:33:46.455",
  9,
  "R",
  "UPDATE",
  10,
  {
	"attrs": {
	  "MP_UNREACH": {
		"flags": "O",
		"value": {
		  "af": "IPV4/FLOWSPEC",
		  "rules": []
		}
	  }
	}
  }
]

Supported features (some partial/wip)

RFCs:

Drafts:

Author

Pawel Foremski @pforemski 2023-2024