From 83692f037ca1747e15d9856958e8dd1855874b63 Mon Sep 17 00:00:00 2001
From: Cort Buffington <n0mjs@me.com>
Date: Sun, 25 Nov 2018 15:07:55 -0600
Subject: [PATCH] Add maximum peer limit for master instances

---
 hb_config.py      |  1 +
 hblink-SAMPLE.cfg |  5 ++++
 hblink.py         | 71 +++++++++++++++++++++++++----------------------
 3 files changed, 44 insertions(+), 33 deletions(-)

diff --git a/hb_config.py b/hb_config.py
index d7024fc..eebf04f 100755
--- a/hb_config.py
+++ b/hb_config.py
@@ -202,6 +202,7 @@ def build_config(_config_file):
                         'MODE': config.get(section, 'MODE'),
                         'ENABLED': config.getboolean(section, 'ENABLED'),
                         'REPEAT': config.getboolean(section, 'REPEAT'),
+                        'MAX_PEERS': config.getint(section, 'MAX_PEERS'),
                         'EXPORT_AMBE': config.getboolean(section, 'EXPORT_AMBE'),
                         'IP': gethostbyname(config.get(section, 'IP')),
                         'PORT': config.getint(section, 'PORT'),
diff --git a/hblink-SAMPLE.cfg b/hblink-SAMPLE.cfg
index 4e08e91..46b40d0 100755
--- a/hblink-SAMPLE.cfg
+++ b/hblink-SAMPLE.cfg
@@ -142,12 +142,17 @@ TGID_ACL: PERMIT:ALL
 # and unused by anything else.
 # Repeat - if True, the master repeats traffic to peers, False, it does nothing.
 #
+# MAX_PEERS -- maximun number of peers that may be connect to this master
+# at any given time. This is very handy if you're allowing hotspots to
+# connect, or using a limited computer like a Raspberry Pi.
+#
 # ACLs:
 # See comments in the GLOBAL stanza
 [MASTER-1]
 MODE: MASTER
 ENABLED: True
 REPEAT: True
+MAX_PEERS: 10
 EXPORT_AMBE: False
 IP:
 PORT: 54000
diff --git a/hblink.py b/hblink.py
index b03674d..1ff847a 100755
--- a/hblink.py
+++ b/hblink.py
@@ -370,41 +370,46 @@ class HBSYSTEM(DatagramProtocol):
 
         elif _command == 'RPTL':    # RPTLogin -- a repeater wants to login
             _peer_id = _data[4:8]
-            # Check for valid Radio ID
-            if acl_check(_peer_id, self._CONFIG['GLOBAL']['REG_ACL']) and acl_check(_peer_id, self._config['REG_ACL']):
-                # Build the configuration data strcuture for the peer
-                self._peers.update({_peer_id: {
-                    'CONNECTION': 'RPTL-RECEIVED',
-                    'PINGS_RECEIVED': 0,
-                    'LAST_PING': time(),
-                    'SOCKADDR': _sockaddr,
-                    'IP': _sockaddr[0],
-                    'PORT': _sockaddr[1],
-                    'SALT': randint(0,0xFFFFFFFF),
-                    'RADIO_ID': str(int(ahex(_peer_id), 16)),
-                    'CALLSIGN': '',
-                    'RX_FREQ': '',
-                    'TX_FREQ': '',
-                    'TX_POWER': '',
-                    'COLORCODE': '',
-                    'LATITUDE': '',
-                    'LONGITUDE': '',
-                    'HEIGHT': '',
-                    'LOCATION': '',
-                    'DESCRIPTION': '',
-                    'SLOTS': '',
-                    'URL': '',
-                    'SOFTWARE_ID': '',
-                    'PACKAGE_ID': '',
-                }})
-                logger.info('(%s) Repeater Logging in with Radio ID: %s, %s:%s', self._system, int_id(_peer_id), _sockaddr[0], _sockaddr[1])
-                _salt_str = hex_str_4(self._peers[_peer_id]['SALT'])
-                self.send_peer(_peer_id, 'RPTACK'+_salt_str)
-                self._peers[_peer_id]['CONNECTION'] = 'CHALLENGE_SENT'
-                logger.info('(%s) Sent Challenge Response to %s for login: %s', self._system, int_id(_peer_id), self._peers[_peer_id]['SALT'])
+            # Check to see if we've reached the maximum number of allowed peers
+            if len(self._peers < self._config['MAX_PEERS']):
+                # Check for valid Radio ID
+                if acl_check(_peer_id, self._CONFIG['GLOBAL']['REG_ACL']) and acl_check(_peer_id, self._config['REG_ACL']):
+                    # Build the configuration data strcuture for the peer
+                    self._peers.update({_peer_id: {
+                        'CONNECTION': 'RPTL-RECEIVED',
+                        'PINGS_RECEIVED': 0,
+                        'LAST_PING': time(),
+                        'SOCKADDR': _sockaddr,
+                        'IP': _sockaddr[0],
+                        'PORT': _sockaddr[1],
+                        'SALT': randint(0,0xFFFFFFFF),
+                        'RADIO_ID': str(int(ahex(_peer_id), 16)),
+                        'CALLSIGN': '',
+                        'RX_FREQ': '',
+                        'TX_FREQ': '',
+                        'TX_POWER': '',
+                        'COLORCODE': '',
+                        'LATITUDE': '',
+                        'LONGITUDE': '',
+                        'HEIGHT': '',
+                        'LOCATION': '',
+                        'DESCRIPTION': '',
+                        'SLOTS': '',
+                        'URL': '',
+                        'SOFTWARE_ID': '',
+                        'PACKAGE_ID': '',
+                    }})
+                    logger.info('(%s) Repeater Logging in with Radio ID: %s, %s:%s', self._system, int_id(_peer_id), _sockaddr[0], _sockaddr[1])
+                    _salt_str = hex_str_4(self._peers[_peer_id]['SALT'])
+                    self.send_peer(_peer_id, 'RPTACK'+_salt_str)
+                    self._peers[_peer_id]['CONNECTION'] = 'CHALLENGE_SENT'
+                    logger.info('(%s) Sent Challenge Response to %s for login: %s', self._system, int_id(_peer_id), self._peers[_peer_id]['SALT'])
+                else:
+                    self.transport.write('MSTNAK'+_peer_id, _sockaddr)
+                    logger.warning('(%s) Invalid Login from Radio ID: %s Denied by Registation ACL', self._system, int_id(_peer_id))
             else:
                 self.transport.write('MSTNAK'+_peer_id, _sockaddr)
-                logger.warning('(%s) Invalid Login from Radio ID: %s Denied by Registation ACL', self._system, int_id(_peer_id))
+                logger.warning('(%s) Registration denied from Radio ID: %s Maximum number of peers exceeded', self._system, int_id(_peer_id))
 
         elif _command == 'RPTK':    # Repeater has answered our login challenge
             _peer_id = _data[4:8]