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BGPLG(8) System Manager's Manual BGPLG(8)

bgplg — looking glass for the OpenBSD Border Gateway Protocol daemon

bgplg

The bgplg CGI program is a looking glass for the bgpd(8) Border Gateway Protocol daemon. The looking glass will provide a simple web interface with read-only access to a restricted set of bgpd(8) and system status information, which is typically used on route servers by Internet Service Providers (ISPs) and Internet eXchange points (IXs). It is intended to be used in a chroot(2) environment in /var/www.

bgplg is disabled by default. It requires four steps to enable the looking glass:

  1. Update the file permission mode to allow the execution of the bgplg CGI program and the additional statically linked programs that have been installed into the chroot(2) environment.

    For example, to allow execution of bgplg and the statically-linked version of bgpctl(8):

    # chmod 0555 /var/www/cgi-bin/bgplg
# chmod 0555 /var/www/bin/bgpctl

    External commands like ping(8) and others will be hidden from the looking glass command list unless given the correct permissions. See the FILES section below for the list of installed programs.

  2. The programs ping(8), ping6(8), traceroute(8) and traceroute6(8) will require a copy of the resolver configuration file resolv.conf(5) in the chroot(2) environment for optional host name lookups. 
    # mkdir /var/www/etc
# cp /etc/resolv.conf /var/www/etc
  3. Start the Border Gateway Protocol daemon with a second, restricted, control socket that can be used from within the chroot(2) environment. See bgpd.conf(5) for more information.

    For example, add the following to /etc/bgpd.conf to have bgpd(8) open a second, restricted, control socket:

    socket "/var/www/run/bgpd.rsock" restricted
  4. Start the httpd(8) and slowcgi(8) servers after configuring the related server section in httpd.conf(5). For example: 
    ext_addr="0.0.0.0"

server "lg.example.net" {
	listen on $ext_addr port 80
	location "/cgi-bin/*" {
		fastcgi
		root ""
	}
}

/var/www/conf/bgplg.css
Optional bgplg CSS style sheet.
/var/www/conf/bgplg.head
Optional bgplg HTML header.
/var/www/conf/bgplg.foot
Optional bgplg HTML footer.
/var/www/run/bgpd.rsock
Position of the second, restricted, control socket of bgpd(8).

The following statically linked executables have been installed into the chroot(2) environment of the httpd(8) server. To enable the corresponding functionality, use the chmod(1) utility to manually set the file permission mode to 0555 or anything appropriate. Some of these executables need the set-user-ID bit, so they should be mounted on a filesystem without the nosuid option.

/var/www/cgi-bin/bgplg
The bgplg CGI executable.
/var/www/bin/bgpctl
The bgpctl(8) program used to query information from bgpd(8)
/var/www/bin/ping
The ping(8) program used to send ICMP ECHO_REQUEST packets to network hosts. Requires the set-user-ID bit, set the permission mode to 4555.
/var/www/bin/ping6
The ping6(8) program used to send ICMPv6 ICMP6_ECHO_REQUEST packets to network hosts. Requires the set-user-ID bit, set the permission mode to 4555.
/var/www/bin/traceroute
The traceroute(8) program used to print the route packets take to network hosts. Requires the set-user-ID bit, set the permission mode to 4555.
/var/www/bin/traceroute6
The traceroute6(8) program used to print the route packets take to inet6(4) network hosts. Requires the set-user-ID bit, set the permission mode to 4555.

bgpctl(8), bgpd(8), bgplgsh(8), httpd(8), slowcgi(8)

The bgplg program first appeared in OpenBSD 4.1. The initial implementation was done in 2005 for DE-CIX, the German commercial internet exchange point.

The bgplg program was written by Reyk Floeter <reyk@openbsd.org>.

To prevent commands from running endlessly, bgplg will kill the corresponding processes after a hard limit of 60 seconds. For example, this can take effect when using traceroute(8) with blackholed or bad routes.

December 14, 2016 openbsd