1

"""

     2

    Track active DHCP hosts on network by dhcp messages.

     3

"""

     4

     5

import logging; log = logging.getLogger('pvl.dhcp.hosts')

     6

     7

# XXX: from db.dhcp_leases instead?

     8

import pvl.verkko.db as db

     9

    10

class DHCPHostsDatabase (object) :

    11

    """

    12

        pvl.verkko.Database dhcp_hosts model for updates.

    13

    """

    14

    15

    def __init__ (self, db) :

    16

        self.db = db

    17

    18

    def create (self) :

    19

        """

    20

            CREATE TABLEs

    21

        """

    22

    23

        log.info("Creating database tables: dhcp_hosts")

    24

        db.dhcp_hosts.create(self.db.engine, checkfirst=True)

    25

    26

    def select (self, distinct=(db.dhcp_hosts.c.gw, db.dhcp_hosts.c.ip), interval=None) :

    27

        """

    28

            SELECT unique gw/ip hosts, for given interval.

    29

        """

    30

    31

        query = db.select(distinct, distinct=True)

    32

    33

        if interval :

    34

            # timedelta

    35

            query = query.where(db.func.now() - db.dhcp_hosts.c.last_seen < interval)

    36

    37

        return self.db.select(query)

    38

    39

    def insert (self, attrs) :

    40

        """

    41

            INSERT new host

    42

        """

    43

    44

        query = db.dhcp_hosts.insert().values(

    45

                ip          = attrs['ip'],

    46

                mac         = attrs['mac'],

    47

                gw          = attrs['gw'],

    48

    49

                first_seen  = attrs['timestamp'],

    50

                count       = 1,

    51

    52

                last_seen   = attrs['timestamp'],

    53

                state       = attrs['state'],

    54

    55

                name        = attrs.get('name'),

    56

                error       = attrs.get('error'),

    57

        )

    58

    59

        # -> id

    60

        return self.db.insert(query)

    61

    62

    def update (self, attrs) :

    63

        """

    64

            UPDATE existing host, or return False if not found.

    65

        """

    66

    67

        table = db.dhcp_hosts

    68

    69

        query = table.update()

    70

        query = query.where((table.c.ip == attrs['ip']) & (table.c.mac == attrs['mac']) & (table.c.gw == attrs['gw']))

    71

        query = query.values(

    72

                count       = db.func.coalesce(table.c.count, 0) + 1,

    73

    74

                # set

    75

                last_seen   = attrs['timestamp'],

    76

                state       = attrs['state'],

    77

        )

    78

    79

        if 'name' in attrs :

    80

            query = query.values(name = attrs['name'])

    81

    82

        if 'error' in attrs :

    83

            query = query.values(error = attrs['error'])

    84

    85

        # any matched rows?

    86

        return self.db.update(query)

    87

    88

    def __call__ (self, item) :

    89

        """

    90

            Process given DHCP syslog message to update the hosts table.

    91

        """

    92

    93

        attrs = {}

    94

    95

        # ignore unless we have enough info to fully identify the client

    96

        # this means that we omit DHCPDISCOVER messages, but we get the OFFER/REQUEST/ACK

    97

        if any(name not in item for name in ('lease', 'hwaddr', 'gateway')) :

    98

            # ignore; we require these

    99

            return

   100

   101

        # do not override error from request on NAK; clear otherwise

   102

        # TODO: DHCPINFORM from 192.168.x.y with error -> rogue dhcp?

   103

        if item.get('type') == 'DHCPNAK' :

   104

            pass

   105

        else :

   106

            attrs['error'] = item.get('error-type') or item.get('error')

   107

   108

        # do not override name unless known

   109

        if item.get('name') :

   110

            attrs['name'] = item.get('name')

   111

   112

        # db: syslog

   113

        ATTR_MAP = (

   114

            ('ip',          'lease'),

   115

            ('mac',         'hwaddr'),

   116

            ('gw',          'gateway'),

   117

   118

            ('timestamp',   'timestamp'),

   119

            ('state',       'type'),

   120

        )

   121

   122

        # generic attrs

   123

        for key, name in ATTR_MAP :

   124

            attrs[key] = item.get(name)

   125

   126

        # update existing?

   127

        if self.update(attrs) :

   128

            log.info("Update: %s", attrs)

   129

   130

        else :

   131

            # new

   132

            log.info("Insert: %s", attrs)

   133

            self.insert(attrs)

   134