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, OrderedDict
from pprint import pprint
from functools import partial

import yaml
import jinja2
import netaddr
from swsscommon import swsscommon


g_run = True
g_debug = False


def log_debug(msg):
    """ Send a message msg to the syslog as DEBUG """
    if g_debug:
        syslog.syslog(syslog.LOG_DEBUG, msg)

def log_notice(msg):
    """ Send a message msg to the syslog as NOTICE """
    syslog.syslog(syslog.LOG_NOTICE, msg)

def log_info(msg):
    """ Send a message msg to the syslog as INFO """
    syslog.syslog(syslog.LOG_INFO, msg)

def log_warn(msg):
    """ Send a message msg to the syslog as WARNING """
    syslog.syslog(syslog.LOG_WARNING, msg)

def log_err(msg):
    """ Send a message msg to the syslog as ERR """
    syslog.syslog(syslog.LOG_ERR, msg)

def log_crit(msg):
    """ Send a message msg to the syslog as CRIT """
    syslog.syslog(syslog.LOG_CRIT, msg)


def run_command(command, shell=False, hide_errors=False):
    """
    Run a linux command. The command is defined as a list. See subprocess.Popen documentation on format
    :param command: command to execute. Type: List of strings
    :param shell: execute the command through shell when True. Type: Boolean
    :param hide_errors: don't report errors to syslog when True. Type: Boolean
    :return: Tuple: integer exit code from the command, stdout as a string, stderr as a string
    """
    log_debug("execute command '%s'." % str(command))
    p = subprocess.Popen(command, shell=shell, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    stdout, stderr = p.communicate()
    if p.returncode != 0:
        if not hide_errors:
            print_tuple = p.returncode, str(command), stdout, stderr
            log_err("command execution returned %d. Command: '%s', stdout: '%s', stderr: '%s'" % print_tuple)

    return p.returncode, stdout, stderr


class ConfigMgr(object):
    """ The class represents frr configuration """
    def __init__(self):
        self.current_config = None

    def reset(self):
        """ Reset stored config """
        self.current_config = None

    def update(self):
        """ Read current config from FRR """
        self.current_config = None
        ret_code, out, err = run_command(["vtysh", "-c", "show running-config"])
        if ret_code != 0:
            log_crit("can't update running config: rc=%d out='%s' err='%s'" % (ret_code, out, err))
            return
        self.current_config = self.to_canonical(out)

    def push(self, cmd):
        """
        Push new changes to FRR
        :param cmd: configuration change for FRR. Type: String
        :return: True if change was applied successfully, False otherwise
        """
        return self.write(cmd)

    def write(self, cmd):
        """
        Write configuration change to FRR.
        :param cmd: new configuration to write into FRR. Type: String
        :return: True if change was applied successfully, False otherwise
        """
        fd, tmp_filename = tempfile.mkstemp(dir='/tmp')
        os.close(fd)
        with open(tmp_filename, 'w') as fp:
            fp.write("%s\n" % cmd)
        command = ["vtysh", "-f", tmp_filename]
        ret_code, out, err = run_command(command)
        if not g_debug:
            os.remove(tmp_filename)
        if ret_code != 0:
            err_tuple = str(cmd), ret_code, out, err
            log_err("ConfigMgr::push(): can't push configuration '%s', rc='%d', stdout='%s', stderr='%s'" % err_tuple)
        if ret_code == 0:
            self.current_config = None  # invalidate config
        return ret_code == 0

    @staticmethod
    def to_canonical(raw_config):
        """
        Convert FRR config into canonical format
        :param raw_config: config in frr format
        :return: frr config in canonical format
        """
        parsed_config = []
        cur_offset = 0
        lines = raw_config.split("\n")
        cur_path = [lines[0]]
        for line in lines:
            if line.strip().startswith('!') or line.strip() == '':
                continue
            n_spaces = ConfigMgr.count_spaces(line)
            s_line = line.strip()
            assert(n_spaces == cur_offset or (n_spaces + 1) == cur_offset or (n_spaces - 1) == cur_offset)
            if n_spaces == cur_offset:
                cur_path[-1] = s_line
            elif n_spaces > cur_offset:
                cur_path.append(s_line)
            elif n_spaces < cur_offset:
                cur_path = cur_path[:-2]
                cur_path.append(s_line)
            parsed_config.append(cur_path[:])
            cur_offset = n_spaces
        return parsed_config

    @staticmethod
    def count_spaces(line):
        """ Count leading spaces in the line """
        return len(line) - len(line.lstrip())

    @staticmethod
    def from_canonical(canonical_config):
        """
        Convert config from canonical format into FRR raw format
        :param canonical_config: config in a canonical format
        :return: config in the FRR raw format
        """
        out = ""
        for lines in canonical_config:
            spaces = len(lines) - 1
            out += " " * spaces + lines[-1] + "\n"

        return out


class TemplateFabric(object):
    """ Fabric for rendering jinja2 templates """
    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=False)
        j2_env.filters['ipv4'] = self.is_ipv4
        j2_env.filters['ipv6'] = self.is_ipv6
        j2_env.filters['pfx_filter'] = self.pfx_filter
        for attr in ['ip', 'network', 'prefixlen', 'netmask']:
            j2_env.filters[attr] = partial(self.prefix_attr, attr)
        self.env = j2_env

    def from_file(self, filename):
        """
        Read a template from a file
        :param filename: filename of the file. Type String
        :return: Jinja2 template object
        """
        return self.env.get_template(filename)

    def from_string(self, tmpl):
        """
        Read a template from a string
        :param tmpl: Text representation of Jinja2 template
        :return: Jinja2 template object
        """
        return self.env.from_string(tmpl)

    @staticmethod
    def is_ipv4(value):
        """ Return True if the value is an ipv4 address """
        if not value:
            return False
        if isinstance(value, netaddr.IPNetwork):
            addr = value
        else:
            try:
                addr = netaddr.IPNetwork(str(value))
            except (netaddr.NotRegisteredError, netaddr.AddrFormatError, netaddr.AddrConversionError):
                return False
        return addr.version == 4

    @staticmethod
    def is_ipv6(value):
        """ Return True if the value is an ipv6 address """
        if not value:
            return False
        if isinstance(value, netaddr.IPNetwork):
            addr = value
        else:
            try:
                addr = netaddr.IPNetwork(str(value))
            except (netaddr.NotRegisteredError, netaddr.AddrFormatError, netaddr.AddrConversionError):
                return False
        return addr.version == 6

    @staticmethod
    def prefix_attr(attr, value):
        """
        Extract attribute from IPNetwork object
        :param attr: attribute to extract
        :param value: the string representation of ip prefix which will be converted to IPNetwork.
        :return: the value of the extracted attribute
        """
        if not value:
            return None
        else:
            try:
                prefix = netaddr.IPNetwork(str(value))
            except (netaddr.NotRegisteredError, netaddr.AddrFormatError, netaddr.AddrConversionError):
                return None
        return str(getattr(prefix, attr))

    @staticmethod
    def pfx_filter(value):
        """INTERFACE Table can have keys in one of the two formats:
           string or tuple - This filter skips the string keys and only
           take into account the tuple.
           For eg - VLAN_INTERFACE|Vlan1000 vs VLAN_INTERFACE|Vlan1000|192.168.0.1/21
        """
        table = OrderedDict()

        if not value:
            return table

        for key, val in value.items():
            if not isinstance(key, tuple):
                continue
            table[key] = val
        return table


class Directory(object):
    """ This class stores values and notifies callbacks which were registered to be executed as soon
        as some value is changed. This class works as DB cache mostly """
    def __init__(self):
        self.data = defaultdict(dict)  # storage. A key is a slot name, a value is a dictionary with data
        self.notify = defaultdict(lambda: defaultdict(list))  # registered callbacks: slot -> path -> handlers[]

    @staticmethod
    def get_slot_name(db, table):
        """ Convert db, table pair into a slot name """
        return db + "__" + table

    def path_traverse(self, slot, path):
        """
        Traverse a path in the storage.
        If the path is an empty string, it returns a value as it is.
        If the path is not an empty string, the method will traverse through the dictionary value.
        Example:
            self.data["key_1"] = { "abc": { "cde": { "fgh": "val_1", "ijk": "val_2" } } }
            self.path_traverse("key_1", "abc/cde") will return True, { "fgh": "val_1", "ijk": "val_2" }
        :param slot: storage key
        :param path: storage path as a string where each internal key is separated by '/'
        :return: a pair: True if the path was found, object if it was found
        """
        if slot not in self.data:
            return False, None
        elif path == '':
            return True, self.data[slot]
        d = self.data[slot]
        for p in path.split("/"):
            if p not in d:
                return False, None
            d = d[p]
        return True, d

    def path_exist(self, db, table, path):
        """
        Check if the path exists in the storage
        :param db: db name
        :param table: table name
        :param path: requested path
        :return: True if the path is available, False otherwise
        """
        slot = self.get_slot_name(db, table)
        return self.path_traverse(slot, path)[0]

    def get_path(self, db, table, path):
        """
        Return the requested path from the storage
        :param db: db name
        :param table: table name
        :param path: requested path
        :return: object if the path was found, None otherwise
        """
        slot = self.get_slot_name(db, table)
        return self.path_traverse(slot, path)[1]

    def put(self, db, table, key, value):
        """
        Put information into the storage. Notify handlers which are dependant to the information
        :param db: db name
        :param table: table name
        :param key: key to change
        :param value: value to put
        :return:
        """
        slot = self.get_slot_name(db, table)
        self.data[slot][key] = value
        if slot in self.notify:
            for path in self.notify[slot].keys():
                if self.path_exist(db, table, path):
                    for handler in self.notify[slot][path]:
                        handler()

    def get(self, db, table, key):
        """
        Get a value from the storage
        :param db: db name
        :param table: table name
        :param key: ket to get
        :return: value for the key
        """
        slot = self.get_slot_name(db, table)
        return self.data[slot][key]

    def get_slot(self, db, table):
        """
        Get an object from the storage
        :param db: db name
        :param table: table name
        :return: object for the slot
        """
        slot = self.get_slot_name(db, table)
        return self.data[slot]

    def remove(self, db, table, key):
        """
        Remove a value from the storage
        :param db: db name
        :param table: table name
        :param key: key to remove
        """
        slot = self.get_slot_name(db, table)
        if slot in self.data:
            if key in self.data[slot]:
                del self.data[slot][key]
            else:
                log_err("Directory: Can't remove key '%s' from slot '%s'. The key doesn't exist" % (key, slot))
        else:
            log_err("Directory: Can't remove key '%s' from slot '%s'. The slot doesn't exist" % (key, slot))

    def remove_slot(self, db, table):
        """
        Remove an object from the storage
        :param db: db name
        :param table: table name
        """
        slot = self.get_slot_name(db, table)
        if slot in self.data:
            del self.data[slot]
        else:
            log_err("Directory: Can't remove slot '%s'. The slot doesn't exist" % slot)

    def available(self, db, table):
        """
        Check if the table is available
        :param db: db name
        :param table: table name
        :return: True if the slot is available, False if not
        """
        slot = self.get_slot_name(db, table)
        return slot in self.data

    def available_deps(self, deps):
        """
        Check if all items from the deps list is available in the storage
        :param deps: list of dependencies
        :return: True if all dependencies are presented, False otherwise
        """
        res = True
        for db, table, path in deps:
            res = res and self.path_exist(db, table, path)
        return res

    def subscribe(self, deps, handler):
        """
        Subscribe the handler to be run as soon as all dependencies are presented
        :param deps:
        :param handler:
        :return:
        """
        for db, table, path in deps:
            slot = self.get_slot_name(db, table)
            self.notify[slot][path].append(handler)


class Runner(object):
    """ Implements main io-loop of the application
        It will run event handlers inside of Manager objects
        when corresponding db/table is updated
    """
    SELECT_TIMEOUT = 1000

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

    def add_manager(self, manager):
        """
        Add a manager to the Runner.
        As soon as new events will be receiving by Runner,
        handlers of corresponding objects will be executed
        :param manager: an object implementing Manager
        """
        db_name = manager.get_database()
        table_name = manager.get_table_name()
        db = swsscommon.SonicDBConfig.getDbId(db_name)
        if db not in self.db_connectors:
            self.db_connectors[db] = swsscommon.DBConnector(db_name, 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(manager.handler)

    def run(self):
        """ Main loop """
        while g_run:
            state, _ = self.selector.select(Runner.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
                log_debug("Received message : '%s'" % str((key, op, fvs)))
                for callback in self.callbacks[subscriber.getDbConnector().getDbId()][subscriber.getTableName()]:
                    callback(key, op, dict(fvs))


class Manager(object):
    """ This class represents a SONiC DB table """
    def __init__(self, common_objs, deps, database, table_name):
        """
        Initialize class
        :param common_objs: common object dictionary
        :param deps: dependencies list
        :param database: database name
        :param table_name: table name
        """
        self.directory = common_objs['directory']
        self.cfg_mgr = common_objs['cfg_mgr']
        self.constants = common_objs['constants']
        self.deps = deps
        self.db_name = database
        self.table_name = table_name
        self.set_queue = []
        self.directory.subscribe(deps, self.on_deps_change)  # subscribe this class method on directory changes

    def get_database(self):
        """ Return associated database """
        return self.db_name

    def get_table_name(self):
        """ Return associated table name"""
        return self.table_name

    def handler(self, key, op, data):
        """
        This method is executed on each add/remove event on the table.
        :param key: key of the table entry
        :param op: operation on the table entry. Could be either 'SET' or 'DEL'
        :param data: associated data of the event. Empty for 'DEL' operation.
        """
        if op == swsscommon.SET_COMMAND:
            if self.directory.available_deps(self.deps):  # all required dependencies are set in the Directory?
                res = self.set_handler(key, data)
                if not res:  # set handler returned False, which means it is not ready to process is. Save it for later.
                    log_debug("'SET' handler returned NOT_READY for the Manager: %s" % self.__class__)
                    self.set_queue.append((key, data))
            else:
                log_debug("Not all dependencies are met for the Manager: %s" % self.__class__)
                self.set_queue.append((key, data))
        elif op == swsscommon.DEL_COMMAND:
            self.del_handler(key)
        else:
            log_err("Invalid operation '%s' for key '%s'" % (op, key))

    def on_deps_change(self):
        """ This method is being executed on every dependency change """
        if not self.directory.available_deps(self.deps):
            return
        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):
        """ Placeholder for 'SET' command """
        log_err("set_handler() wasn't implemented for %s" % self.__class__.__name__)

    def del_handler(self, key):
        """ Placeholder for 'DEL' command """
        log_err("del_handler wasn't implemented for %s" % self.__class__.__name__)


class BGPDataBaseMgr(Manager):
    """ This class updates the Directory object when db table is updated """
    def __init__(self, common_objs, db, table):
        """
        Initialize the object
        :param common_objs: common object dictionary
        :param db: name of the db
        :param table: name of the table in the db
        """
        super(BGPDataBaseMgr, self).__init__(
            common_objs,
            [],
            db,
            table,
        )

    def set_handler(self, key, data):
        """ Implementation of 'SET' command for this class """
        self.directory.put(self.db_name, self.table_name, key, data)

        return True

    def del_handler(self, key):
        """ Implementation of 'DEL' command for this class """
        self.directory.remove(self.db_name, self.table_name, key)


class InterfaceMgr(Manager):
    """ This class updates the Directory object when interface-related table is updated """
    def __init__(self, common_objs, db, table):
        """
        Initialize the object
        :param common_objs: common object dictionary
        :param db: name of the db
        :param table: name of the table in the db
        """
        super(InterfaceMgr, self).__init__(
            common_objs,
            [],
            db,
            table,
        )

    def set_handler(self, key, data):
        """ Implementation of 'SET' command.
        Similar to BGPDataBaseMgr but enriches data object with additional data """
        # Interface table can have two keys,
        # one with ip prefix and one without ip prefix
        if '|' in key:
            interface_name, network_str = key.split('|', 1)
            try:
                network = netaddr.IPNetwork(str(network_str))
            except (netaddr.NotRegisteredError, netaddr.AddrFormatError, netaddr.AddrConversionError):
                log_warn("Subnet '%s' format is wrong for interface '%s'" % (network_str, data["interface"]))
                return True
            data["interface"] = interface_name
            data["prefixlen"] = str(network.prefixlen)
            ip = str(network.ip)
            self.directory.put("LOCAL", "local_addresses", ip, data)
        self.directory.put(self.db_name, self.table_name, key, data)
        self.directory.put("LOCAL", "interfaces", key, data)
        return True

    def del_handler(self, key):
        """ Implementation of 'DEL' command
        Also removes data object enrichment """
        if '|' in key:
            interface, network = key.split('|', 1)
            try:
                network = netaddr.IPNetwork(str(network))
            except (netaddr.NotRegisteredError, netaddr.AddrFormatError, netaddr.AddrConversionError):
                log_warn("Subnet '%s' format is wrong for interface '%s'" % (network, interface))
                return
            ip = str(network.ip)
            self.directory.remove("LOCAL", "local_addresses", ip)
        self.directory.remove(self.db_name, self.table_name, key)
        self.directory.remove("LOCAL", "interfaces", key)


class BGPPeerGroupMgr(object):
    """ This class represents peer-group and routing policy for the peer_type """
    def __init__(self, common_objs, base_template):
        """
        Construct the object
        :param common_objs: common objects
        :param base_template: path to the directory with Jinja2 templates
        """
        self.cfg_mgr = common_objs['cfg_mgr']
        self.constants = common_objs['constants']
        tf = common_objs['tf']
        self.policy_template = tf.from_file(base_template + "policies.conf.j2")
        self.peergroup_template = tf.from_file(base_template + "peer-group.conf.j2")

    def update(self, name, **kwargs):
        """
        Update peer-group and routing policy for the peer with the name
        :param name: name of the peer. Used for logging only
        :param kwargs: dictionary with parameters for rendering
        """
        rc_policy = self.update_policy(name, **kwargs)
        rc_pg = self.update_pg(name, **kwargs)
        return rc_policy and rc_pg

    def update_policy(self, name, **kwargs):
        """
        Update routing policy for the peer
        :param name: name of the peer. Used for logging only
        :param kwargs: dictionary with parameters for rendering
        """
        try:
            policy = self.policy_template.render(**kwargs)
        except jinja2.TemplateError as e:
            log_err("Can't render policy template name: '%s': %s" % (name, str(e)))
            return False

        return self.update_entity(policy, "Routing policy for peer '%s'" % name)

    def update_pg(self, name, **kwargs):
        """
        Update peer-group for the peer
        :param name: name of the peer. Used for logging only
        :param kwargs: dictionary with parameters for rendering
        """
        try:
            pg = self.peergroup_template.render(**kwargs)
        except jinja2.TemplateError as e:
            log_err("Can't render peer-group template: '%s': %s" % (name, str(e)))
            return False

        if kwargs['vrf'] == 'default':
            cmd = ('router bgp %s\n' % kwargs['bgp_asn']) + pg
        else:
            cmd = ('router bgp %s vrf %s\n' % (kwargs['bgp_asn'], kwargs['vrf'])) + pg

        return self.update_entity(cmd, "Peer-group for peer '%s'" % name)

    def update_entity(self, cmd, txt):
        """
        Send commands to FRR
        :param cmd: commands to send in a raw form
        :param txt: text for the syslog output
        :return:
        """
        ret_code = self.cfg_mgr.push(cmd)
        if ret_code:
            log_info("%s was updated" % txt)
        else:
            log_err("Can't update %s" % txt)
        return ret_code


class BGPPeerMgrBase(Manager):
    """ Manager of BGP peers """
    def __init__(self, common_objs, db_name, table_name, peer_type):
        """
        Initialize the object
        :param common_objs: common objects
        :param table_name: name of the table with peers
        :param peer_type: type of the peers. It is used to find right templates
        """
        self.common_objs = common_objs
        self.constants = self.common_objs["constants"]
        self.fabric = common_objs['tf']
        self.peer_type = peer_type

        base_template = "bgpd/templates/" + self.constants["bgp"]["peers"][peer_type]["template_dir"] + "/"
        self.templates = {
            "add":         self.fabric.from_file(base_template + "instance.conf.j2"),
            "delete":      self.fabric.from_string('no neighbor {{ neighbor_addr }}'),
            "shutdown":    self.fabric.from_string('neighbor {{ neighbor_addr }} shutdown'),
            "no shutdown": self.fabric.from_string('no neighbor {{ neighbor_addr }} shutdown'),
        }

        deps = [
            ("CONFIG_DB", swsscommon.CFG_DEVICE_METADATA_TABLE_NAME, "localhost/bgp_asn"),
            ("CONFIG_DB", swsscommon.CFG_LOOPBACK_INTERFACE_TABLE_NAME, "Loopback0"),
            ("LOCAL", "local_addresses", ""),
            ("LOCAL", "interfaces", ""),
        ]

        self.check_neig_meta = 'bgp' in self.constants \
                               and 'use_neighbors_meta' in self.constants['bgp'] \
                               and self.constants['bgp']['use_neighbors_meta']
        self.check_deployment_id = 'bgp' in self.constants \
                               and 'use_deployment_id' in self.constants['bgp'] \
                               and self.constants['bgp']['use_deployment_id']

        if self.check_neig_meta:
            deps.append(("CONFIG_DB", swsscommon.CFG_DEVICE_NEIGHBOR_METADATA_TABLE_NAME, ""))

        if self.check_deployment_id:
            deps.append(("CONFIG_DB", swsscommon.CFG_DEVICE_METADATA_TABLE_NAME, "localhost/deployment_id"))

        super(BGPPeerMgrBase, self).__init__(
            common_objs,
            deps,
            db_name,
            table_name,
        )

        self.peers = self.load_peers()
        self.peer_group_mgr = BGPPeerGroupMgr(self.common_objs, base_template)
        return

    def set_handler(self, key, data):
        """
         It runs on 'SET' command
        :param key: key of the changed table
        :param data: the data associated with the change
        """
        vrf, nbr = self.split_key(key)
        peer_key = (vrf, nbr)
        if peer_key not in self.peers:
            return self.add_peer(vrf, nbr, data)
        else:
            return self.update_peer(vrf, nbr, data)

    def add_peer(self, vrf, nbr, data):
        """
        Add a peer into FRR. This is used if the peer is not existed in FRR yet
        :param vrf: vrf name. Name is equal "default" for the global vrf
        :param nbr: neighbor ip address (name for dynamic peer type)
        :param data: associated data
        :return: True if this adding was successful, False otherwise
        """
        print_data = vrf, nbr, data
        bgp_asn = self.directory.get_slot("CONFIG_DB", swsscommon.CFG_DEVICE_METADATA_TABLE_NAME)["localhost"]["bgp_asn"]
        #
        lo0_ipv4 = self.get_lo0_ipv4()
        if lo0_ipv4 is None:
            log_warn("Loopback0 ipv4 address is not presented yet")
            return False
        #
        if "local_addr" not in data:
            log_warn("Peer %s. Missing attribute 'local_addr'" % nbr)
        else:
            # The bgp session that belongs to a vnet cannot be advertised as the default BGP session.
            # So we need to check whether this bgp session belongs to a vnet.
            interface = self.get_local_interface(data["local_addr"])
            if not interface:
                print_data = nbr, data["local_addr"]
                log_debug("Peer '%s' with local address '%s' wait for the corresponding interface to be set" % print_data)
                return False
            vnet = self.get_vnet(interface)
            if vnet:
                # Ignore the bgp session that is in a vnet
                log_info("Ignore the BGP peer '%s' as the interface '%s' is in vnet '%s'" % (nbr, interface, vnet))
                return True

        kwargs = {
            'CONFIG_DB__DEVICE_METADATA': self.directory.get_slot("CONFIG_DB", swsscommon.CFG_DEVICE_METADATA_TABLE_NAME),
            'constants': self.constants,
            'bgp_asn': bgp_asn,
            'vrf': vrf,
            'neighbor_addr': nbr,
            'bgp_session': data,
            'loopback0_ipv4': lo0_ipv4,
        }
        if self.check_neig_meta:
            neigmeta = self.directory.get_slot("CONFIG_DB", swsscommon.CFG_DEVICE_NEIGHBOR_METADATA_TABLE_NAME)
            if 'name' in data and data["name"] not in neigmeta:
                log_info("DEVICE_NEIGHBOR_METADATA is not ready for neighbor '%s' - '%s'" % (nbr, data['name']))
                return False
            kwargs['CONFIG_DB__DEVICE_NEIGHBOR_METADATA'] = neigmeta

        tag = data['name'] if 'name' in data else nbr
        self.peer_group_mgr.update(tag, **kwargs)

        try:
            cmd = self.templates["add"].render(**kwargs)
        except jinja2.TemplateError as e:
            msg = "Peer '(%s|%s)'. Error in rendering the template for 'SET' command '%s'" % print_data
            log_err("%s: %s" % (msg, str(e)))
            return True
        if cmd is not None:
            ret_code = self.apply_op(cmd, vrf)
            key = (vrf, nbr)
            if ret_code:
                self.peers.add(key)
                log_info("Peer '(%s|%s)' added with attributes '%s'" % print_data)
            else:
                log_err("Peer '(%s|%s)' wasn't added." % (vrf, nbr))

        return True

    def update_peer(self, vrf, nbr, data):
        """
        Update a peer. This is used when the peer is already in the FRR
        Update support only "admin_status" for now
        :param vrf: vrf name. Name is equal "default" for the global vrf
        :param nbr: neighbor ip address (name for dynamic peer type)
        :param data: associated data
        :return: True if this adding was successful, False otherwise
        """
        if "admin_status" in data:
            self.change_admin_status(vrf, nbr, data)
        else:
            log_err("Peer '(%s|%s)': Can't update the peer. Only 'admin_status' attribute is supported" % (vrf, nbr))

        return True

    def change_admin_status(self, vrf, nbr, data):
        """
        Change admin status of a peer
        :param vrf: vrf name. Name is equal "default" for the global vrf
        :param nbr: neighbor ip address (name for dynamic peer type)
        :param data: associated data
        :return: True if this adding was successful, False otherwise
        """
        if data['admin_status'] == 'up':
            self.apply_admin_status(vrf, nbr, "no shutdown", "up")
        elif data['admin_status'] == 'down':
            self.apply_admin_status(vrf, nbr, "shutdown", "down")
        else:
            print_data = vrf, nbr, data['admin_status']
            log_err("Peer '%s|%s': Can't update the peer. It has wrong attribute value attr['admin_status'] = '%s'" % print_data)

    def apply_admin_status(self, vrf, nbr, template_name, admin_state):
        """
        Render admin state template and apply the command to the FRR
        :param vrf: vrf name. Name is equal "default" for the global vrf
        :param nbr: neighbor ip address (name for dynamic peer type)
        :param template_name: name of the template to render
        :param admin_state: desired admin state
        :return: True if this adding was successful, False otherwise
        """
        print_data = vrf, nbr, admin_state
        ret_code = self.apply_op(self.templates[template_name].render(neighbor_addr=nbr), vrf)
        if ret_code:
            log_info("Peer '%s|%s' admin state is set to '%s'" % print_data)
        else:
            log_err("Can't set peer '%s|%s' admin state to '%s'." % print_data)

    def del_handler(self, key):
        """
        'DEL' handler for the BGP PEER tables
        :param key: key of the neighbor
        """
        vrf, nbr = self.split_key(key)
        peer_key = (vrf, nbr)
        if peer_key not in self.peers:
            log_warn("Peer '(%s|%s)' has not been found" % (vrf, nbr))
            return
        cmd = self.templates["delete"].render(neighbor_addr=nbr)
        ret_code = self.apply_op(cmd, vrf)
        if ret_code:
            log_info("Peer '(%s|%s)' has been removed" % (vrf, nbr))
            self.peers.remove(key)
        else:
            log_err("Peer '(%s|%s)' hasn't been removed" % (vrf, nbr))

    def apply_op(self, cmd, vrf):
        """
        Push commands cmd into FRR
        :param cmd: commands in raw format
        :param vrf: vrf where the commands should be applied
        :return: True if no errors, False if there are errors
        """
        bgp_asn = self.directory.get_slot("CONFIG_DB", swsscommon.CFG_DEVICE_METADATA_TABLE_NAME)["localhost"]["bgp_asn"]
        if vrf == 'default':
            cmd = ('router bgp %s\n' % bgp_asn) + cmd
        else:
            cmd = ('router bgp %s vrf %s\n' % (bgp_asn, vrf)) + cmd
        return self.cfg_mgr.push(cmd)

    def get_lo0_ipv4(self):
        """
        Extract Loopback0 ipv4 address from the Directory
        :return: ipv4 address for Loopback0, None if nothing found
        """
        loopback0_ipv4 = None
        for loopback in self.directory.get_slot("CONFIG_DB", swsscommon.CFG_LOOPBACK_INTERFACE_TABLE_NAME).iterkeys():
            if loopback.startswith("Loopback0|"):
                loopback0_prefix_str = loopback.replace("Loopback0|", "")
                loopback0_ip_str = loopback0_prefix_str[:loopback0_prefix_str.find('/')]
                if TemplateFabric.is_ipv4(loopback0_ip_str):
                    loopback0_ipv4 = loopback0_ip_str
                    break

        return loopback0_ipv4

    def get_local_interface(self, local_addr):
        """
        Get interface according to the local address from the directory
        :param: directory: Directory object that stored metadata of interfaces
        :param: local_addr: Local address of the interface
        :return: Return the metadata of the interface with the local address
                 If the interface has not been set, return None
        """
        local_addresses = self.directory.get_slot("LOCAL", "local_addresses")
        # Check if the local address of this bgp session has been set
        if local_addr not in local_addresses:
            return None
        local_address = local_addresses[local_addr]
        interfaces = self.directory.get_slot("LOCAL", "interfaces")
        # Check if the information for the interface of this local address has been set
        if local_address.has_key("interface") and local_address["interface"] in interfaces:
            return interfaces[local_address["interface"]]
        else:
            return None

    @staticmethod
    def get_vnet(interface):
        """
        Get the VNet name of the interface
        :param: interface: The metadata of the interface
        :return: Return the vnet name of the interface if this interface belongs to a vnet,
                 Otherwise return None
        """
        if interface.has_key("vnet_name") and interface["vnet_name"]:
            return interface["vnet_name"]
        else:
            return None

    @staticmethod
    def split_key(key):
        """
        Split key into ip address and vrf name. If there is no vrf, "default" would be return for vrf
        :param key: key to split
        :return: vrf name extracted from the key, peer ip address extracted from the key
        """
        if '|' not in key:
            return 'default', key
        else:
            return tuple(key.split('|', 1))

    @staticmethod
    def load_peers():
        """
        Load peers from FRR.
        :return: set of peers, which are already installed in FRR
        """
        command = ["vtysh", "-c", "show bgp vrfs json"]
        ret_code, out, err = run_command(command)
        if ret_code == 0:
            js_vrf = json.loads(out)
            vrfs = js_vrf['vrfs'].keys()
        else:
            log_crit("Can't read bgp vrfs: %s" % err)
            raise Exception("Can't read bgp vrfs: %s" % err)
        peers = set()
        for vrf in vrfs:
            command = ["vtysh", "-c", 'show bgp vrf %s neighbors json' % str(vrf)]
            ret_code, out, err = run_command(command)
            if ret_code == 0:
                js_bgp = json.loads(out)
                for nbr in js_bgp.keys():
                    peers.add((vrf, nbr))
            else:
                log_crit("Can't read vrf '%s' neighbors: %s" % (vrf, str(err)))
                raise Exception("Can't read vrf '%s' neighbors: %s" % (vrf, str(err)))

        return peers


class ZebraSetSrc(Manager):
    """ This class initialize "set src" settings for zebra """
    def __init__(self, common_objs, db, table):
        """
        Initialize the object
        :param common_objs: common object dictionary
        :param db: name of the db
        :param table: name of the table in the db
        """
        super(ZebraSetSrc, self).__init__(
            common_objs,
            [],
            db,
            table,
        )
        tf = common_objs['tf']
        self.zebra_set_src_template = tf.from_file("zebra/zebra.set_src.conf.j2")
        self.lo_ipv4 = None
        self.lo_ipv6 = None

    def set_handler(self, key, data):
        """ Implementation of 'SET' command for this class """
        self.directory.put(self.db_name, self.table_name, key, data)
        #
        if key.startswith("Loopback0|") and "state" in data and data["state"] == "ok":
            ip_addr_w_mask = key.replace("Loopback0|", "")
            slash_pos = ip_addr_w_mask.rfind("/")
            if slash_pos == -1:
                log_err("Wrong Loopback0 ip address: '%s'" % ip_addr_w_mask)
                return True
            ip_addr = ip_addr_w_mask[:slash_pos]
            try:
                if TemplateFabric.is_ipv4(ip_addr) and self.lo_ipv4 is None:
                    self.lo_ipv4 = ip_addr
                    txt = self.zebra_set_src_template.render(rm_name="RM_SET_SRC", lo_ip=ip_addr, ip_proto="")
                elif TemplateFabric.is_ipv6(ip_addr) and self.lo_ipv6 is None:
                    self.lo_ipv6 = ip_addr
                    txt = self.zebra_set_src_template.render(rm_name="RM_SET_SRC6", lo_ip=ip_addr, ip_proto="v6")
                else:
                    log_err("Got ambiguous ip address '%s'" % ip_addr)
                    return True
            except jinja2.TemplateError as e:
                log_err("Error while rendering 'set src' template: %s" % str(e))
                return True
            if self.cfg_mgr.push(txt):
                log_info("The 'set src' configuration with Loopback0 ip '%s' was pushed" % ip_addr)
            else:
                log_err("The 'set src' configuration with Loopback0 ip '%s' wasn't pushed" % ip_addr)
        return True

    def del_handler(self, key):
        """ Implementation of 'DEL' command for this class """
        self.directory.remove(self.db_name, self.table_name, key)
        log_warn("Delete command is not supported for 'zebra set src' templates")


def wait_for_daemons(daemons, seconds):
    """
    Wait until FRR daemons are ready for requests
    :param daemons: list of FRR daemons to wait
    :param seconds: number of seconds to wait, until raise an error
    """
    stop_time = datetime.datetime.now() + datetime.timedelta(seconds=seconds)
    log_info("Start waiting for FRR daemons: %s" % str(datetime.datetime.now()))
    while datetime.datetime.now() < stop_time:
        ret_code, out, err = run_command(["vtysh", "-c", "show daemons"], hide_errors=True)
        if ret_code == 0 and all(daemon in out for daemon in daemons):
            log_info("All required daemons have connected to vtysh: %s" % str(datetime.datetime.now()))
            return
        else:
            log_warn("Can't read daemon status from FRR: %s" % str(err))
        time.sleep(0.1)  # sleep 100 ms
    raise RuntimeError("FRR daemons hasn't been started in %d seconds" % seconds)


def read_constants():
    """ Read file with constants values from /etc/sonic/constants.yml """
    with open('/etc/sonic/constants.yml') as fp:
        content = yaml.load(fp)
        if "constants" not in content:
            log_crit("/etc/sonic/constants.yml doesn't have 'constants' key")
            raise Exception("/etc/sonic/constants.yml doesn't have 'constants' key")
        return content["constants"]


def main():
    """ Main function """
    wait_for_daemons(["bgpd", "zebra", "staticd"], seconds=20)
    #
    common_objs = {
        'directory': Directory(),
        'cfg_mgr':   ConfigMgr(),
        'tf':        TemplateFabric(),
        'constants': read_constants(),
    }
    managers = [
        # Config DB managers
        BGPDataBaseMgr(common_objs, "CONFIG_DB", swsscommon.CFG_DEVICE_METADATA_TABLE_NAME),
        BGPDataBaseMgr(common_objs, "CONFIG_DB", swsscommon.CFG_DEVICE_NEIGHBOR_METADATA_TABLE_NAME),
        # Interface managers
        InterfaceMgr(common_objs, "CONFIG_DB", swsscommon.CFG_INTF_TABLE_NAME),
        InterfaceMgr(common_objs, "CONFIG_DB", swsscommon.CFG_LOOPBACK_INTERFACE_TABLE_NAME),
        InterfaceMgr(common_objs, "CONFIG_DB", swsscommon.CFG_VLAN_INTF_TABLE_NAME),
        InterfaceMgr(common_objs, "CONFIG_DB", swsscommon.CFG_LAG_INTF_TABLE_NAME),
        # State DB managers
        ZebraSetSrc(common_objs, "STATE_DB", swsscommon.STATE_INTERFACE_TABLE_NAME),
        # Peer Managers
        BGPPeerMgrBase(common_objs, "CONFIG_DB", swsscommon.CFG_BGP_NEIGHBOR_TABLE_NAME, "general"),
        BGPPeerMgrBase(common_objs, "CONFIG_DB", "BGP_MONITORS", "monitors"),
        BGPPeerMgrBase(common_objs, "CONFIG_DB", "BGP_PEER_RANGE", "dynamic"),
    ]
    runner = Runner()
    for mgr in managers:
        runner.add_manager(mgr)
    runner.run()


def signal_handler(_, __):  # signal_handler(signum, frame)
    """ signal handler """
    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:
        log_notice("Keyboard interrupt")
    except RuntimeError as exc:
        log_crit(str(exc))
        rc = -2
        if g_debug:
            raise
    except Exception as exc:
        log_crit("Got an exception %s: Traceback: %s" % (str(exc), traceback.format_exc()))
        rc = -1
        if g_debug:
            raise
    finally:
        syslog.closelog()
    try:
        sys.exit(rc)
    except SystemExit:
        os._exit(rc)