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bgpq4 - bgp filtering automation tool

	bgpq4 [-h host[:port]] [-S sources] [-Ez] [-f asn | -F fmt | -G asn | -t] [-46ABbDdJjNnpsUX] [-a asn] [-r len] [-R len] [-m max] [-W len] OBJECTS [...] EXCEPT OBJECTS

The bgpq4 utility used to generate configuration (prefix-lists, extended access-lists, policy-statement terms and as-path lists) based on RADB data.

The options are as follows:

Generate IPv4 prefix/access-lists (default).

Generate IPv6 prefix/access-lists (IPv4 by default).

Try to aggregate generated filters as much as possible (not all output formats supported).

Specify ASN that shall be denied in case of empty prefix-list (OpenBGPD).

Generate output in OpenBGPD format.

Generate output in BIRD format.

Enable some debugging output.

Generate extended access-list (Cisco) or policy-statement term using route-filters (Juniper), [ip|ipv6]-prefix-list (Nokia) or prefix-filter (OpenBGPD)

Generate input as-path access-list for adjacent as AS number.

Generate output in user-defined format.

Generate output as-path access-list.

Host running IRRD database (default: rr.ntt.net).

Generate config for Juniper.

Generate output in JSON format.

Generate config for MikroTik.

Maximum length of accepted prefixes (default: 32 for IPv4, 128 for IPv6).

Extra match conditions for Juniper route-filters. See the examples section.

Generate config for Nokia SR OS (former Alcatel-Lucent) MD-CLI.

Generate config for Nokia SR OS (former Alcatel-Lucent) classic CLI.

Name of generated configuration stanza.

Limit recursion depth when expanding. This slows bgpq4 a bit, but sometimes is a useful feature to prevent generated filters from growing too big.

Enable use of private ASNs and ASNs used for documentation purpose only (default: disabled).

Allow more-specific routes with masklen starting with specified length.

Allow more-specific routes up to specified masklen too. (Please, note: objects with prefix-length greater than specified length will be always allowed.)

Generate sequence numbers in IOS-style prefix-lists.

Use specified sources only (recommended: RADB,RIPE,APNIC).

Generate as-sets for OpenBGPD (OpenBSD 6.4+), BIRD and JSON formats.

Disable pipelining (not recommended).

Generate output in Huawei format.

Generate as-path strings of a given length maximum (0 for infinity).

Generate output in Cisco IOS XR format.

Generate Juniper route-filter-list (JunOS 16.2+).

OBJECTS means networks (in prefix format), autonomous systems, as-sets and route-sets. If multiple objects are specified they will be merged.

You can exclude autonomous sets, as-sets and route-sets found during expansion from future expansion.

Generating prefix filter for MikroTik for AS20597:

 $ ./bgpq4 -Kl eltel-v4 AS20597
 /routing filter add action=accept chain="eltel-v4" prefix=81.9.0.0/20
 /routing filter add action=accept chain="eltel-v4" prefix=81.9.32.0/20
 /routing filter add action=accept chain="eltel-v4" prefix=81.9.96.0/20
 /routing filter add action=accept chain="eltel-v4" prefix=81.222.128.0/20
 /routing filter add action=accept chain="eltel-v4" prefix=81.222.160.0/20
 /routing filter add action=accept chain="eltel-v4" prefix=81.222.192.0/18
 /routing filter add action=accept chain="eltel-v4" prefix=85.249.8.0/21
 /routing filter add action=accept chain="eltel-v4" prefix=85.249.224.0/19
 /routing filter add action=accept chain="eltel-v4" prefix=89.112.0.0/17
 /routing filter add action=accept chain="eltel-v4" prefix=217.170.64.0/19

Generating named Juniper prefix-filter for AS20597:

 $ bgpq4 -Jl eltel-v4 AS20597
 policy-options {
 replace:
  prefix-list eltel-v4 {
     81.9.0.0/20;
     81.9.32.0/20;
     81.9.96.0/20;
     81.222.128.0/20;
     81.222.192.0/18;
     85.249.8.0/21;
     85.249.224.0/19;
     89.112.0.0/19;
     89.112.4.0/22;
     89.112.32.0/19;
     89.112.64.0/19;
     217.170.64.0/20;
     217.170.80.0/20;
  }
 }

For Cisco we can use aggregation (-A) flag to make this prefix-filter more compact:

 $ bgpq4 -Al eltel-v4 AS20597
 no ip prefix-list eltel-v4
 ip prefix-list eltel-v4 permit 81.9.0.0/20
 ip prefix-list eltel-v4 permit 81.9.32.0/20
 ip prefix-list eltel-v4 permit 81.9.96.0/20
 ip prefix-list eltel-v4 permit 81.222.128.0/20
 ip prefix-list eltel-v4 permit 81.222.192.0/18
 ip prefix-list eltel-v4 permit 85.249.8.0/21
 ip prefix-list eltel-v4 permit 85.249.224.0/19
 ip prefix-list eltel-v4 permit 89.112.0.0/18 ge 19 le 19
 ip prefix-list eltel-v4 permit 89.112.4.0/22
 ip prefix-list eltel-v4 permit 89.112.64.0/19
 ip prefix-list eltel-v4 permit 217.170.64.0/19 ge 20 le 20

and, as you see, prefixes 89.112.0.0/19 and 89.112.32.0/19 now aggregated into single entry

ip prefix-list eltel permit 89.112.0.0/18 ge 19 le 19.

Well, for Juniper we can generate even more interesting policy-statement, using -M <extra match conditions>, -r <len>, -R <len> and hierarchical names:

 $ bgpq4 -AJEl eltel/specifics -r 29 -R 32 -M "community blackhole" AS20597
policy-options {
 policy-statement eltel {
  term specifics {
replace:
   from {
    community blackhole;
    route-filter 81.9.0.0/20 prefix-length-range /29-/32;
    route-filter 81.9.32.0/20 prefix-length-range /29-/32;
    route-filter 81.9.96.0/20 prefix-length-range /29-/32;
    route-filter 81.222.128.0/20 prefix-length-range /29-/32;
    route-filter 81.222.192.0/18 prefix-length-range /29-/32;
    route-filter 85.249.8.0/21 prefix-length-range /29-/32;
    route-filter 85.249.224.0/19 prefix-length-range /29-/32;
    route-filter 89.112.0.0/17 prefix-length-range /29-/32;
    route-filter 217.170.64.0/19 prefix-length-range /29-/32;
   }
  }
 }
}

generated policy-option term now allows more-specific routes in range /29 - /32 for eltel networks if they marked with community 'blackhole' (defined elsewhere in configuration).

Of course, bgpq4 supports IPv6 (-6):

 $ bgpq4 -6l as-retn-v6 AS-RETN6
 no ipv6 prefix-list as-retn-v6
 ipv6 prefix-list as-retn-v6 permit 2001:7fb:fe00::/48
 ipv6 prefix-list as-retn-v6 permit 2001:7fb:fe01::/48
 [....]

and assumes your device supports 32-bit ASNs

 $ bgpq4 -Jf 112 AS-SPACENET
 policy-options {
 replace:
  as-path-group NN {
   as-path a0 "^112(112)*$";
   as-path a1 "^112(.)*(1898|5539|8495|8763|8878|12136|12931|15909)$";
   as-path a2 "^112(.)*(21358|23600|24151|25152|31529|34127|34906)$";
   as-path a3 "^112(.)*(35052|41720|43628|44450|196611)$";
  }
 }

see AS196611 in the end of the list ? That's a 32-bit ASN.

If you want to generate configuration not for routers, but for some other programs/systems, you may use user-defined formatting, like in example below:

$ bgpq4 -F "ipfw add pass all from %n/%l to any\\n" as3254
ipfw add pass all from 62.244.0.0/18 to any
ipfw add pass all from 91.219.29.0/24 to any
ipfw add pass all from 91.219.30.0/24 to any
ipfw add pass all from 193.193.192.0/19 to any

Recognized format characters: '%n' - network, '%l' - mask length, '%a' - aggregate low mask length, '%A' - aggregate high mask length, '%N' - object name, '%m' - object mask and '%i' - inversed mask. Recognized escape characters: '\n' - new line, '\t' - tabulation. Please note that no new lines inserted automatically after each sentence, you have to add them into format string manually, elsewhere output will be in one line (sometimes it makes sense):

$ bgpq4 -6F "%n/%l; " as-eltel
2001:1b00::/32; 2620:4f:8000::/48; 2a04:bac0::/29; 2a05:3a80::/48;

When everything is OK, bgpq4 generates result to standard output and exits with status == 0. In case of errors they are printed to stderr and program exits with non-zero status.

To improve bgpq4 performance when expanding extra-large AS-SETs you shall tune OS settings to enlarge TCP send buffer.

FreeBSD can be tuned in the following way:

sysctl -w net.inet.tcp.sendbuf_max=2097152

Linux can be tuned in the following way:

sysctl -w net.ipv4.tcp_window_scaling=1
sysctl -w net.core.rmem_max=2097152
sysctl -w net.core.wmem_max=2097152
sysctl -w net.ipv4.tcp_rmem="4096 87380 2097152"
sysctl -w net.ipv4.tcp_wmem="4096 65536 2097152"

Please note that generated prefix-lists may not fit your router's limitations. For example, JunOS supports only 85,325 prefixes in each prefix-list 4.

This project uses autotools. If you are building from the repository, run the following command to prepare the build system:

./bootstrap

In order to compile the software, run:

./configure
make
make install

If you wish to remove the generated build system files from your working tree, run:

make maintainer-clean

In order to create a distribution archive, run:

make dist

Users and interested parties can subscribe to the BGPQ4 mailing list [email protected].

NLNOG's BGP Filter Guide

Alexandre Snarskii, Christian David, Claudio Jeker, Job Snijders, Massimiliano Stucchi, Michail Litvak, Peter Schoenmaker, Roelf Wichertjes, and contributions from many others.

BGPQ4 is maintained by Job Snijders <[email protected]>.

https://github.com/bgp/bgpq4