Initial zeroconf app and example config for its use

container/example-zeroconf.yaml

@@ -0,0 +1,34 @@
+nets:
+  dtnA:
+    subnet4: "192.168.100.0/24"
+  dtnB:
+    subnet4: "192.168.110.0/24"
+#    subnet6: "fda1:1cec:f450:c055::/64"
+
+nodes:
+  node000:
+    nets: [dtnA]
+    keys:
+      sign:
+        keytype: SECP256R1
+    config:
+      apps:
+        zeroconf:
+          enumerate: true
+      tls_enable: false
+
+  node001:
+    nets: [dtnA, dtnB]
+    config:
+      apps:
+        zeroconf:
+          offer: true
+      tls_enable: false
+
+  node002:
+    nets: [dtnB]
+    config:
+      apps:
+        zeroconf:
+          enumerate: true
+      tls_enable: false

container/example.yaml

@@ -9,26 +9,30 @@ nodes:
   node000:
     nets: [dtnA]
     keys:
-       sign:
-          keytype: SECP256R1
+      sign:
+        keytype: SECP256R1
     config:
-       apps:
-          nmp:
-             enable: true
-       tls_enable: true
+      apps:
+        nmp:
+          enable: true
+        zeroconf:
+          enumerate: true
+      tls_enable: true
 
   node001:
     nets: [dtnA, dtnB]
     config:
-       apps:
-          nmp:
-             enable: true
-       tls_enable: true
+      apps:
+        nmp:
+          enable: true
+        zeroconf:
+          offer: true
+      tls_enable: true
 
   node002:
     nets: [dtnB]
     config:
-       apps:
-          nmp:
-             enable: true
-       tls_enable: true
+      apps:
+        nmp:
+          enable: true
+      tls_enable: true

container/run.py

@@ -263,11 +263,11 @@ def action(self, act):
                 bp_rx_routes = extconfig.get('bp_rx_routes', [])
                 bp_rx_routes += [
                     {
-                        'eid_pattern': r'dtn://{{node_name}}/.*',
+                        'eid_pattern': f'dtn://{node_name}/.*',
                         'action': 'deliver',
                     },
                     {
-                        'eid_pattern': '".*"',
+                        'eid_pattern': '.*',
                         'action': 'forward',
                     },
                 ]

pyproject.toml

@@ -8,7 +8,7 @@ version = "0.0.0"
 authors = [
   { name="Brian Sipos", email="[email protected]" },
 ]
-description = "A demonstration agent for the DTN BPv7/TCPCLv4/UDPCL"
+description = "A demonstration agent for the DTN BPv7/TCPCLv4/UDPCLv2"
 readme = "README.md"
 license = { text="LGPL-3" }
 requires-python = ">=3.7"
@@ -29,14 +29,14 @@ dependencies = [
   "cryptography >=0.9",
   "certvalidator",
   "dbus-python",
-  "lakers-python",
   "portion >=2.1",
   "psutil",
   "PyGObject >=3.34", # glib integration
   "PyYAML",
   "python3-dtls",
   "scapy >=2.4,<2.4.5",
   "six",
+  "zeroconf",
 ]
 
 [project.optional-dependencies]
@@ -84,4 +84,4 @@ bp-agent = "bp.cmd:main"
 
 [project.urls]
 "Homepage" = "https://github.com/BrianSipos/dtn-demo-agent"
-"Bug Tracker" = "https://github.com/BrianSipos/dtn-demo-agent/issues"
+"Bug Tracker" = "https://github.com/BrianSipos/dtn-demo-agent/issues"

src/bp/agent.py

@@ -173,6 +173,12 @@ def exec_loop(self):
                 # wait for graceful shutdown
                 eloop.run()
 
+    def add_tx_route(self, item:TxRouteItem):
+        self._config.tx_route_table.append(item)
+
+    def get_cla(self, name:str) -> bp.cla.AbstractAdaptor:
+        return self._cl_agent[name]
+
     def _bus_name_changed(self, servname, old_owner, new_owner):
         for cl_agent in self._cl_agent.values():
             if cl_agent.serv_name == servname:
@@ -350,6 +356,7 @@ def _do_fwd(self):
             ctr.record_action('forward')
         except Exception as err:
             self._logger.error('Failed to forward bundle %s: %s', ctr.log_name(), err)
+            self._logger.debug('%s', traceback.format_exc())
             ctr.record_action('delete', StatusReport.ReasonCode.NO_ROUTE)
 
         self._finish_bundle(ctr)
@@ -435,7 +442,7 @@ def cl_attach(self, cltype, servname):
         except KeyError:
             raise ValueError('Invalid cltype: {}'.format(cltype))
 
-        agent = cls()
+        agent = cls(agent=self)
         agent.serv_name = servname
         agent.peer_node_seen = self._cl_peer_node_seen(cltype)
         agent.recv_bundle_finish = self._cl_recv_bundle_finish(cltype)

src/bp/app/__init__.py

@@ -4,3 +4,4 @@
 from . import fragment
 from . import bpsec
 from . import nmp
+from . import zeroconf

src/bp/app/nmp.py

@@ -1,4 +1,4 @@
-''' Application layer adaptors.
+''' Prototype of Secure Advertisement and Neighborhood Discovery (SAND).
 '''
 import cbor2
 from dataclasses import dataclass, field, fields

src/bp/app/zeroconf.py

@@ -0,0 +1,168 @@
+''' Prototype of Zero-Configuration BP router discovery.
+'''
+from gi.repository import GLib as glib
+import ipaddress
+import logging
+import random
+import re
+import socket
+from typing import List
+import ifaddr
+from zeroconf import (
+    Zeroconf,
+    ServiceInfo,
+    ServiceBrowser,
+    ServiceStateChange,
+)
+
+from bp.config import Config, TxRouteItem
+from bp.app.base import app, AbstractApplication
+
+LOGGER = logging.getLogger(__name__)
+
+SVCLOCAL = '_dtn-bundle._tcp.local.'
+''' Global service name to register under '''
+
+
+@app('zeroconf')
+class App(AbstractApplication):
+
+    DBUS_IFACE = 'org.ietf.dtn.bp.zeroconf'
+    ''' Interface name '''
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        self._config = None
+        self._zco = None
+        self._browser = None
+
+    def load_config(self, config:Config):
+        super().load_config(config)
+        self._config = config.apps.get(self._app_name, {})
+
+        self._zco = Zeroconf()
+
+        if self._config.get('offer', False):
+            glib.timeout_add(1e3 * random.randint(5, 8), self._offer)
+        if self._config.get('enumerate', False):
+            glib.timeout_add(1e3 * random.randint(5, 8), self._enumerate)
+
+    def _iface_addrs(self) -> List[ipaddress._IPAddressBase]:
+        all_addrs = []
+        for adapter in ifaddr.get_adapters():
+            for ipobj in adapter.ips:
+                if isinstance(ipobj.ip, tuple):
+                    # ipv6
+                    addr = ipobj.ip[0]
+                else:
+                    # ipv4
+                    addr = ipobj.ip
+
+                addrobj = ipaddress.ip_address(addr)
+                if addrobj.is_loopback or addrobj.is_reserved:
+                    continue
+
+                all_addrs.append(addrobj)
+
+        return all_addrs
+
+    def _iface_nets(self) -> List[ipaddress._BaseNetwork]:
+        all_nets = []
+        for adapter in ifaddr.get_adapters():
+            for ipobj in adapter.ips:
+                if isinstance(ipobj.ip, tuple):
+                    # ipv6
+                    addr = ipobj.ip[0]
+                else:
+                    # ipv4
+                    addr = ipobj.ip
+
+                ifaceobj = ipaddress.ip_interface(f'{addr}/{ipobj.network_prefix}')
+                if ifaceobj.ip.is_loopback or ifaceobj.ip.is_reserved:
+                    continue
+
+                all_nets.append(ifaceobj.network)
+
+        return all_nets
+
+    def _offer(self):
+        ''' Deferred async offer on mDNS. '''
+
+        hostname = (
+            self._config.get('hostname')
+            or socket.gethostname().split('.', 1)[0]
+        )
+        fqdn = hostname + '.local.'
+
+        # Offer all reachable unicast addresses
+        all_addrs = self._iface_addrs()
+        # ignore when no usable addresses
+        if not all_addrs:
+            return False
+
+        instname = self._config.get('instance', hostname)
+        instlocal = f'{instname}.{SVCLOCAL}'
+
+        servinfo = ServiceInfo(
+            SVCLOCAL,
+            instlocal,
+            weight=1,
+            server=fqdn,
+            addresses=list(map(str, all_addrs)),
+            port=4556,
+            properties=dict(
+              txtvers=1,
+              protovers=4,
+            ),
+        )
+        self._zco.register_service(servinfo)
+        LOGGER.info('mDNS registered as %s on %s',
+                    instlocal, all_addrs)
+
+        return False
+
+    def _enumerate(self):
+
+        self._browser = ServiceBrowser(
+            self._zco,
+            [SVCLOCAL],
+            handlers=[self._serv_state_change]
+        )
+
+        return False
+
+    def _serv_state_change(self, zeroconf, service_type, name, state_change):
+        all_nets = self._iface_nets()
+        LOGGER.info('Iface nets: %s', all_nets)
+
+        if state_change == ServiceStateChange.Added:
+            info = zeroconf.get_service_info(service_type, name)
+            LOGGER.info('Service added: %s', info)
+
+            addr_objs = list(map(ipaddress.ip_address, info.addresses))
+            LOGGER.info('Possible addresses: %s', addr_objs)
+            usable_addrs = [
+                addr
+                for addr in addr_objs
+                if [net for net in all_nets if addr in net]
+            ]
+            LOGGER.info('Usable addresses: %s', usable_addrs)
+            if not usable_addrs:
+                return
+            best_addr = str(usable_addrs[0])
+            best_port = int(info.port)
+
+            route = TxRouteItem(
+                eid_pattern=re.compile(r'.*'),
+                next_nodeid=None,  # FIXME needed?
+                cl_type='tcpcl',
+                raw_config=dict(
+                    address=best_addr,
+                    port=best_port,
+                ),
+            )
+            LOGGER.info('Route item %s', route)
+            self._agent.add_tx_route(route)
+
+            self._agent.get_cla('tcpcl').connect(best_addr, best_port)