pppoe: T3090: migrate to vyos.ifconfig library to use the full potential

Now that MSS clamping is done on the "per-interface" level the entire PPPoE
stuff would have needed to get a full copy in GNU BASH for this or, participate
in the common library.

Add a new PPP ip-up script named 99-vyos-pppoe-callback which will call the
vyos.ifconfig.PPPoEIf.update() function to configure everything as done with
all other interfaces. This removes duplicated code for VRF assignment and route
installation when a PPPoE interface is brought up or down.

1 files changed, 59 insertions, 0 deletions

diff --git a/src/etc/ppp/ip-up.d/99-vyos-pppoe-callback b/src/etc/ppp/ip-up.d/99-vyos-pppoe-callback
new file mode 100755
index 000000000..bb918a468
--- /dev/null
+++ b/src/etc/ppp/ip-up.d/99-vyos-pppoe-callback
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This is a Python hook script which is invoked whenever a PPPoE session goes
+# "ip-up". It will call into our vyos.ifconfig library and will then execute
+# common tasks for the PPPoE interface. The reason we have to "hook" this is
+# that we can not create a pppoeX interface in advance in linux and then connect
+# pppd to this already existing interface.
+
+from sys import argv
+from sys import exit
+
+from syslog import syslog
+from syslog import openlog
+from syslog import LOG_PID
+from syslog import LOG_INFO
+
+from vyos.configquery import ConfigTreeQuery
+from vyos.ifconfig import PPPoEIf
+from vyos.util import read_file
+
+# When the ppp link comes up, this script is called with the following
+# parameters
+#       $1      the interface name used by pppd (e.g. ppp3)
+#       $2      the tty device name
+#       $3      the tty device speed
+#       $4      the local IP address for the interface
+#       $5      the remote IP address
+#       $6      the parameter specified by the 'ipparam' option to pppd
+
+if (len(argv) < 7):
+    exit(1)
+
+interface = argv[6]
+dialer_pid = read_file(f'/var/run/{interface}.pid')
+
+openlog(ident=f'pppd[{dialer_pid}]', facility=LOG_INFO)
+syslog('executing ' + argv[0])
+
+conf = ConfigTreeQuery()
+pppoe = conf.get_config_dict(['interfaces', 'pppoe', argv[6]],
+                             get_first_key=True, key_mangling=('-', '_'))
+pppoe['ifname'] = argv[6]
+
+p = PPPoEIf(pppoe['ifname'])
+p.update(pppoe)