BGP
The Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the internet. BGP is classified as a path-vector routing protocol, and it makes routing decisions based on paths, network policies, or rule-sets configured by a network operator.
Configuration
Following an example BGP configuration with one session.
{
"interfaces": {
"network": [
{
"interface": "eth1",
"address": "10.0.1.2/24",
"gateway": "10.0.1.1"
}
]
},
"bgp": [
{
"local-ipv4-address": "10.0.1.2",
"peer-ipv4-address": "10.0.1.1",
"raw-update-file": "test.bgp",
"local-as": 65001,
"peer-as": 65001
}
]
}
{ "bgp": {} }
Attribute |
Description |
Default |
|---|---|---|
network-interface |
BGP local interface (source-interface) |
first network interface |
local-ipv4-address |
BGP local IPv4 address (source-address) |
network interface address |
local-as |
BGP local AS |
65000 |
peer-ipv4-address |
BGP peer address |
|
peer-as |
BGP peer AS |
local AS |
holdtime |
BGP holdtime in seconds |
90 |
id |
BGP identifier |
1.2.3.4 |
reconnect |
BGP reconnect |
true |
start-traffic |
BGP start global traffic after RAW update |
false |
teardown-time |
BGP teardown time in seconds |
5 |
raw-update-file |
BGP RAW update file |
BGP Sessions
Every BGP session is opened with the capabilities for the following address families:
IPv4 unicast
IPv4 labelled unicast
IPv6 unicast
IPv6 labelled unicast
Limitations
BGP authentication is currently not supported but already planned as enhancement in one of the next releases.
RAW Update Files
The BNG Blaster is able to inject BGP messages from a pre-compiled RAW update file into the defined sessions. A RAW update file is not more than a pre-compiled binary stream of BGP messages, typically but not limited to update messages.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ +
| Marker |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Type | ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++
.
.
.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ +
| Marker |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Type | ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++
Those files can be created using the included BGP RAW update generator
script bgpupdate or manually using libraries like scapy or converters
from PCAP or MRT files.
The configured raw-update-file under the BGP session is loaded
during Blaster startup phase and send as soon as the session is
established.
The bgp-raw-update command allows to send further updates during
the session lifetime.
$ sudo bngblaster-cli run.sock bgp-raw-update file update1.bgp
This allows in example to load a full table after session has started and manually trigger a series of changes using incremental updates files.
All BGP RAW update files are loaded once and can than be used by multiple sessions. Meaning if two or more sessions reference the same file identified by file name, this file is loaded once into memory and used by multiple sessions.
Therefore for incremental updates, it may makes sense to pre-load
via bgp-raw-update-files configuration.
{
"bgp": [
{
"local-ipv4-address": "10.0.1.2",
"peer-ipv4-address": "10.0.1.1",
"raw-update-file": "start.bgp",
"local-as": 65001,
"peer-as": 65001
}
],
"bgp-raw-update-files": [
"update1.bgp",
"update2.bgp"
]
}
Incremental updates not listed here will be loaded dynamically as soon as referenced by first session.
BGP RAW Update Generator
The BGP RAW update generator is a simple tool to generate BGP RAW update streams for use with the BNG Blaster.
$ bgpupdate --help
usage: bgpupdate [-h] [-a ASN] -n ADDRESS [-N N] -p PREFIX [-P N] [-m LABEL]
[-M N] [-l LOCAL_PREF] [-f FILE] [-w] [-s STREAMS]
[--stream-tx-label LABEL] [--stream-tx-inner-label LABEL]
[--stream-rx-label LABEL] [--stream-rx-label-num N]
[--stream-threads N] [--stream-pps N]
[--stream-interface IFACE] [--stream-append] [--end-of-rib]
[--append] [--pcap FILE] [--log-level {warning,info,debug}]
The BGP RAW update generator is a simple tool to generate BGP RAW update
streams for use with the BNG Blaster.
optional arguments:
-h, --help show this help message and exit
-a ASN, --asn ASN autonomous system number
-n ADDRESS, --next-hop-base ADDRESS
next-hop base address (IPv4 or IPv6)
-N N, --next-hop-num N
next-hop count
-p PREFIX, --prefix-base PREFIX
prefix base network (IPv4 or IPv6)
-P N, --prefix-num N prefix count
-m LABEL, --label-base LABEL
label base
-M N, --label-num N label count
-l LOCAL_PREF, --local-pref LOCAL_PREF
local preference
-f FILE, --file FILE output file
-w, --withdraw withdraw prefixes
-s STREAMS, --streams STREAMS
generate BNG Blaster traffic stream file
--stream-tx-label LABEL
stream TX outer label
--stream-tx-inner-label LABEL
stream TX inner label
--stream-rx-label LABEL
stream RX label
--stream-rx-label-num N
stream RX label count
--stream-threads N stream TX threads
--stream-pps N stream packets per seconds
--stream-interface IFACE
stream interface
--stream-append append to stream file if exist
--end-of-rib add end-of-rib message
--append append to file if exist
--pcap FILE write BGP updates to PCAP file
--log-level {warning,info,debug}
logging Level
The python BGP RAW update generator is a python script which uses scapy to build BGP messages. Therefore this tool can be easily modified, extend or used as blueprint for your own tools to generate valid BGP update streams.