bgpq3 - bgp filtering automation for Cisco and Juniper routers
bgpq3 [-h host] [-S sources] [-EP] [-f asn | -G asn] [-36ADdJjX] [-R len] [-m max] OBJECTS [...]
The bgpq3 utility used to generate Cisco and Juniper prefix-lists, extended access-lists, policy-statement terms and as-path lists based on RADB data.
The options are as follows:
-3
assume that your device is asn32-capable.
-6
generate IPv6 prefix/access-lists (IPv4 by default).
-A
try to aggregate generated filters as much as possible (not all output formats supported).
-d
enable some debugging output.
-D
use asdot notation for Cisco as-path access-lists.
-E
generate extended access-list (Cisco) or policy-statement term using route-filters (Juniper).
-f number
generate input as-path access-list.
-G number
generate output as-path access-list.
-h host
host running IRRD database (default: whois.radb.net).
-J
generate config for Juniper (default: Cisco).
-j
generate output in JSON format (default: Cisco).
-m len
maximum length of accepted prefixes (default: 32 for IPv4, 128 for IPv6).
-M match
extra match conditions for Juniper route-filters.
-l name
name of generated entry.
-P
generate prefix-list (default behaviour, flag added for backward compatibility only).
-R len
allow more-specific routes up to specified masklen too. (Please, note: objects with prefix-length greater than specified length will be always allowed.)
-S sources
use specified sources only (default: RADB,RIPE,APNIC).
-T
disable pipelining.
-X
generate config for Cisco IOS XR devices (plain IOS by default).
OBJECTS means networks (in prefix format), autonomous systems and as-macros.
Generating named Juniper prefix-filter for AS20597:
user@host:~>bgpq3 -Jl eltel AS20597
policy-options {
replace:
prefix-list eltel {
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:
user@host:~>bgpq3 -Al eltel AS20597
no ip prefix-list eltel
ip prefix-list eltel permit 81.9.0.0/20
ip prefix-list eltel permit 81.9.32.0/20
ip prefix-list eltel permit 81.9.96.0/20
ip prefix-list eltel permit 81.222.128.0/20
ip prefix-list eltel permit 81.222.192.0/18
ip prefix-list eltel permit 85.249.8.0/21
ip prefix-list eltel permit 85.249.224.0/19
ip prefix-list eltel permit 89.112.0.0/18 ge 19 le 19
ip prefix-list eltel permit 89.112.4.0/22
ip prefix-list eltel permit 89.112.64.0/19
ip prefix-list eltel 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> and hierarchical names:
user@host:~>bgpq3 -AJEl eltel/specifics -R 32 -M "community blackhole" AS20597
policy-options {
policy-statement eltel {
term specifics {
replace:
from {
community blackhole;
route-filter 81.9.0.0/20 upto /32;
route-filter 81.9.32.0/20 upto /32;
route-filter 81.9.96.0/20 upto /32;
route-filter 81.222.128.0/20 upto /32;
route-filter 81.222.192.0/18 upto /32;
route-filter 85.249.8.0/21 upto /32;
route-filter 85.249.224.0/19 upto /32;
route-filter 89.112.0.0/18 prefix-length-range /19-/32;
route-filter 89.112.64.0/19 upto /32;
route-filter 217.170.64.0/19 prefix-length-range /20-/32;
}
}
}
}
generated policy-option term now allows all more-specific routes for eltel networks if they marked with community 'blackhole' (defined elsewhere in configuration).
Of course, bgpq3 supports IPv6 (-6):
user@host:~>bgpq3 -6l as-retn-6 AS-RETN6
no ipv6 prefix-list as-retn-6
ipv6 prefix-list as-retn-6 permit 2001:7fb:fe00::/48
ipv6 prefix-list as-retn-6 permit 2001:7fb:fe01::/48
[....]
and ASN32
user@host:~>bgpq3 -J3f 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|23456|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 AS3.3 in 'asplain' notation.
If your router does not support ASN32 (yet) you should not use switch -3, and the result will be next:
user@host:~>bgpq3 -f 112 AS-SPACENET
no ip as-path access-list NN
ip as-path access-list NN permit ^112( 112)*$
ip as-path access-list NN permit ^112( [0-9]+)* (1898|5539|8495|8763)$
ip as-path access-list NN permit ^112( [0-9]+)* (8878|12136|12931|15909)$
ip as-path access-list NN permit ^112( [0-9]+)* (21358|23456|23600|24151)$
ip as-path access-list NN permit ^112( [0-9]+)* (25152|31529|34127|34906)$
ip as-path access-list NN permit ^112( [0-9]+)* (35052|41720|43628|44450)$
AS196611 is no more in the list, however, AS23456 (transition AS) would
have been added to list if it were not present.
When everything is OK, bgpq3 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.
When using bgpq3 to expand extra-large AS-SETs, bgpq3 may stuck
due to lacking tcp buffer size. To avoid this, tune your OS.
FreeBSD can be tuned in the following way:
sysctl -w net.inet.tcp.sendbuf_max=16777216
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.
Alexandre Snarskii snar@snar.spb.ru