sonic-buildimage/dockers/docker-fpm-frr/bgpcfgd

#!/usr/bin/env python

import sys
import subprocess
import datetime
import time
import syslog
import signal
import traceback
import os
import tempfile
import json
from collections import defaultdict
from pprint import pprint
from pprint import pformat

import jinja2
import netaddr
from swsscommon import swsscommon


g_run = True
g_debug = False


def run_command(command, shell=False):
    str_cmd = " ".join(command)
    if g_debug:
        syslog.syslog(syslog.LOG_DEBUG, "execute command {}.".format(str_cmd))
    p = subprocess.Popen(command, shell=shell, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    stdout, stderr = p.communicate()
    if p.returncode != 0:
        syslog.syslog(syslog.LOG_ERR, 'command execution returned {}. Command: "{}", stdout: "{}", stderr: "{}"'.format(p.returncode, str_cmd, stdout, stderr))

    return p.returncode, stdout, stderr


class TemplateFabric(object):
    def __init__(self):
        j2_template_paths = ['/usr/share/sonic/templates']
        j2_loader = jinja2.FileSystemLoader(j2_template_paths)
        j2_env = jinja2.Environment(loader=j2_loader, trim_blocks=True)
        j2_env.filters['ipv4'] = self.is_ipv4
        j2_env.filters['ipv6'] = self.is_ipv6
        self.env = j2_env

    def from_file(self, filename):
        return self.env.get_template(filename)

    def from_string(self, tmpl):
        return self.env.from_string(tmpl)

    @staticmethod
    def is_ipv4(value):
        if not value:
            return False
        if isinstance(value, netaddr.IPNetwork):
            addr = value
        else:
            try:
                addr = netaddr.IPNetwork(str(value))
            except:
                return False
        return addr.version == 4

    @staticmethod
    def is_ipv6(value):
        if not value:
            return False
        if isinstance(value, netaddr.IPNetwork):
            addr = value
        else:
            try:
                addr = netaddr.IPNetwork(str(value))
            except:
                return False
        return addr.version == 6


class Daemon(object):
    SELECT_TIMEOUT = 1000

    def __init__(self):
        self.db_connectors = {}
        self.selector = swsscommon.Select()
        self.callbacks = defaultdict(lambda : defaultdict(list)) # db -> table -> []
        self.subscribers = set()

    def add_manager(self, db, table_name, callback):
        if db not in self.db_connectors:
            self.db_connectors[db] = swsscommon.DBConnector(db, swsscommon.DBConnector.DEFAULT_UNIXSOCKET, 0)

        if table_name not in self.callbacks[db]:
            conn = self.db_connectors[db]
            subscriber = swsscommon.SubscriberStateTable(conn, table_name)
            self.subscribers.add(subscriber)
            self.selector.addSelectable(subscriber)
        self.callbacks[db][table_name].append(callback)

    def run(self):
        while g_run:
            state, _ = self.selector.select(Daemon.SELECT_TIMEOUT)
            if state == self.selector.TIMEOUT:
                continue
            elif state == self.selector.ERROR:
                raise Exception("Received error from select")

            for subscriber in self.subscribers:
                key, op, fvs = subscriber.pop()
                if not key:
                    continue
                if g_debug:
                    syslog.syslog(syslog.LOG_DEBUG, "Received message : {}".format((key, op, fvs)))
                for callback in self.callbacks[subscriber.getDbConnector().getDbId()][subscriber.getTableName()]:
                    callback(key, op, dict(fvs))


class Directory(object):
    def __init__(self):
        self.data = defaultdict(dict)
        self.notify = defaultdict(lambda: defaultdict(list))

    def path_exist(self, slot, path):
        if slot not in self.data:
            return False
        elif path == '':
            return True
        d = self.data[slot]
        for p in path.split("/"):
            if p not in d:
                return False
            d = d[p]
        return True

    def get_path(self, slot, path):
        if slot not in self.data:
            return None
        elif path == '':
            return self.data[slot]
        d = self.data[slot]
        for p in path.split("/"):
            if p not in d:
                return None
            d = d[p]
        return d

    def put(self, slot, key, value):
        self.data[slot][key] = value
        if slot in self.notify:
            for path in self.notify[slot].keys():
                if self.path_exist(slot, path):
                    for handler in self.notify[slot][path]:
                        handler()

    def get(self, slot, key):
        return self.data[slot][key]

    def remove(self, slot, key):
        if slot in self.data:
            if key in self.data[slot]:
                del self.data[slot][key]
            else:
                syslog.syslog(syslog.LOG_ERR, "Directory: Can't remove key '%s' from slot '%s'. The key doesn't exist" % (key, slot))
        else:
            syslog.syslog(syslog.LOG_ERR, "Directory: Can't remove key '%s' from slot '%s'. The slot doesn't exist" % (key, slot))

    def remove_slot(self, slot, key):
        if slot in self.data:
            del self.data[slot]
        else:
            syslog.syslog(syslog.LOG_ERR, "Directory: Can't remove slot '%s'. The slot doesn't exist" % slot)

    def get_slot(self, slot):
        return self.data[slot]

    def available_slot(self, slot):
        return slot in self.data

    def available_deps(self, deps):
        res = True
        for slot, path in deps:
            res = res and self.path_exist(slot, path)
        return res

    def subscribe(self, deps, handler):
        for slot, path in deps:
            self.notify[slot][path].append(handler)


class Manager(object):
    def __init__(self, daemon, directory, deps, database, table_name):
        self.directory = directory
        self.deps = deps
        self.set_queue = []
        daemon.add_manager(database, table_name, self.handler)
        directory.subscribe(deps, self.on_deps_change)

    def handler(self, key, op, data):
        if op == swsscommon.SET_COMMAND:
            if self.directory.available_deps(self.deps):
                res = self.set_handler(key, data)
                if not res:
                    self.set_queue.append((key, data))
            else:
                self.set_queue.append((key, data))
        elif op == swsscommon.DEL_COMMAND:
            self.del_handler(key)
        else:
            syslog.syslog(syslog.LOG_ERR, 'Invalid operation "%s" for key "%s"' % (op, key))

    def on_deps_change(self):
        new_queue = []
        for key, data in self.set_queue:
            res = self.set_handler(key, data)
            if not res:
                new_queue.append((key, data))
        self.set_queue = new_queue

    def set_handler(self, key, data):
        syslog.syslog(syslog.LOG_ERR, "%s wasn't implemented for %s" % (self.__name__, self.__class__))

    def del_handler(self, key):
        syslog.syslog(syslog.LOG_ERR, "%s wasn't implemented for %s" % (self.__name__, self.__class__))


class BGPDeviceMetaMgr(Manager):
    def __init__(self, daemon, directory):
        super(BGPDeviceMetaMgr, self).__init__(
            daemon,
            directory,
            [],
            swsscommon.CONFIG_DB,
            swsscommon.CFG_DEVICE_METADATA_TABLE_NAME
        )

    def set_handler(self, key, data):
        if key != "localhost" or "bgp_asn" not in data:
            return
        if self.directory.path_exist("meta", "localhost/bgp_asn"):
            bgp_asn = self.directory.get_path("meta", "localhost/bgp_asn")
            if bgp_asn == data["bgp_asn"]:
                return
        self.directory.put("meta", key, data)

        return True

    def del_handler(self, key):
        self.directory.remove("meta", key)


class BGPNeighborMetaMgr(Manager):
    def __init__(self, daemon, directory):
        super(BGPNeighborMetaMgr, self).__init__(
            daemon,
            directory,
            [],
            swsscommon.CONFIG_DB,
            swsscommon.CFG_DEVICE_NEIGHBOR_METADATA_TABLE_NAME
        )

    def set_handler(self, key, data):
        self.directory.put("neigmeta", key, data)

        return True

    def del_handler(self, key):
        self.directory.remove("neigmeta", key)


class BGPPeerMgr(Manager):
    def __init__(self, daemon, directory):
        super(BGPPeerMgr, self).__init__(
            daemon,
            directory,
            [
                ("meta", "localhost/bgp_asn"),
                ("neigmeta", ""),
            ],
            swsscommon.CONFIG_DB,
            swsscommon.CFG_BGP_NEIGHBOR_TABLE_NAME
        )
        self.peers = self.load_peers()
        fabric = TemplateFabric()
        self.templates = {
            "add":         fabric.from_file('bgpd.peer.conf.j2'),
            "delete":      fabric.from_string('no neighbor {{ neighbor_addr }}'),
            "shutdown":    fabric.from_string('neighbor {{ neighbor_addr }} shutdown'),
            "no shutdown": fabric.from_string('no neighbor {{ neighbor_addr }} shutdown'),
        }

    def set_handler(self, key, data):
        if key not in self.peers:
            cmd = None
            neigmeta = self.directory.get_slot("neigmeta")
            if 'name' in data and data["name"] not in neigmeta:
                return False
            try:
                cmd = self.templates["add"].render(
                    DEVICE_METADATA=self.directory.get_slot("meta"),
                    DEVICE_NEIGHBOR_METADATA=neigmeta,
                    neighbor_addr=key,
                    bgp_session=data
                )
            except:
                syslog.syslog(syslog.LOG_ERR, 'Peer {}. Error in rendering the template for "SET" command {}'.format(key, data))
                return True
            if cmd is not None:
                rc = self.apply_op(cmd)
                if rc:
                    self.peers.add(key)
                    syslog.syslog(syslog.LOG_INFO, 'Peer {} added with attributes {}'.format(key, data))
                else:
                    syslog.syslog(syslog.LOG_ERR, "Peer {} wasn't added.".format(key))
        else:
            # when the peer is already configured we support "shutdown/no shutdown"
            # commands for the peers only
            if "admin_status" in data:
                if data['admin_status'] == 'up':
                    rc = self.apply_op(self.templates["no shutdown"].render(neighbor_addr=key))
                    if rc:
                        syslog.syslog(syslog.LOG_INFO, 'Peer {} admin state is set to "up"'.format(key))
                    else:
                        syslog.syslog(syslog.LOG_ERR, "Peer {} admin state wasn't set to 'up'.".format(key))
                elif data['admin_status'] == 'down':
                    rc = self.apply_op(self.templates["shutdown"].render(neighbor_addr=key))
                    if rc:
                        syslog.syslog(syslog.LOG_INFO, 'Peer {} admin state is set to "down"'.format(key))
                    else:
                        syslog.syslog(syslog.LOG_ERR, "Peer {} admin state wasn't set to 'down'.".format(key))
                else:
                    syslog.syslog(syslog.LOG_ERR, "Peer {}: Can't update the peer. has wrong attribute value attr['admin_status'] = '{}'".format(key, data['admin_status']))
            else:
                syslog.syslog(syslog.LOG_ERR, "Peer {}: Can't update the peer. No 'admin_status' attribute in the request".format(key))
        return True

    def del_handler(self, key):
        if key not in self.peers:
            syslog.syslog(syslog.LOG_WARNING, 'Peer {} has not been found'.format(key))
            return
        cmd = self.templates["delete"].render(neighbor_addr=key)
        rc = self.apply_op(cmd)
        if rc:
            syslog.syslog(syslog.LOG_INFO, 'Peer {} has been removed'.format(key))
            self.peers.remove(key)
        else:
            syslog.syslog(syslog.LOG_ERR, "Peer {} hasn't been removed".format(key))

    def apply_op(self, cmd):
        bgp_asn = self.directory.get_slot("meta")["localhost"]["bgp_asn"]
        fd, tmp_filename = tempfile.mkstemp(dir='/tmp')
        os.close(fd)
        with open(tmp_filename, 'w') as fp:
            fp.write('router bgp %s\n' % bgp_asn)
            fp.write("%s\n" % cmd)

        command = ["vtysh", "-f",  tmp_filename]
        rc, _, _ = run_command(command)
        os.remove(tmp_filename)
        return rc == 0

    @staticmethod
    def load_peers():
        peers = set()
        command = ["vtysh", "-c", "show bgp neighbors json"]
        rc, out, err = run_command(command)
        if rc == 0:
            js_bgp = json.loads(out)
            peers = set(js_bgp.keys())
        return peers


def wait_for_bgpd():
    # wait for 20 seconds
    stop_time = datetime.datetime.now() + datetime.timedelta(seconds=20)
    syslog.syslog(syslog.LOG_INFO, "Start waiting for bgpd: %s" % str(datetime.datetime.now()))
    while datetime.datetime.now() < stop_time:
        rc, out, err = run_command(["vtysh", "-c", "show daemons"])
        if rc == 0 and "bgpd" in out:
            syslog.syslog(syslog.LOG_INFO, "bgpd connected to vtysh: %s" % str(datetime.datetime.now()))
            return
        time.sleep(0.1) # sleep 100 ms
    raise RuntimeError("bgpd hasn't been started in 20 seconds")


def main():
    managers = [
        BGPDeviceMetaMgr,
        BGPNeighborMetaMgr,
        BGPPeerMgr,
    ]
    wait_for_bgpd()
    daemon = Daemon()
    directory = Directory()
    manager_instanses = [ manager(daemon, directory) for manager in managers ]
    daemon.run()


def signal_handler(signum, frame):
    global g_run
    g_run = False


if __name__ == '__main__':
    rc = 0
    try:
        syslog.openlog('bgpcfgd')
        signal.signal(signal.SIGTERM, signal_handler)
        signal.signal(signal.SIGINT, signal_handler)
        main()
    except KeyboardInterrupt:
        syslog.syslog(syslog.LOG_NOTICE, "Keyboard interrupt")
    except RuntimeError as e:
        syslog.syslog(syslog.LOG_CRIT, "%s" % str(e))
        rc = -2
    except Exception as e:
        syslog.syslog(syslog.LOG_CRIT, "Got an exception %s: Traceback: %s" % (str(e), traceback.format_exc()))
        rc = -1
    finally:
        syslog.closelog()
    try:
        sys.exit(rc)
    except SystemExit:
        os._exit(rc)