1 files changed, 33 insertions, 1 deletions

diff --git a/tests/integration/harness.py b/tests/integration/harness.py
index b98ce83..a9d38ca 100644
--- a/tests/integration/harness.py
+++ b/tests/integration/harness.py
@@ -20,6 +20,9 @@ import urllib.error
 import urllib.parse
 import urllib.request
 
+# groupip_1 in src/ot_livesync.c
+LIVESYNC_GROUP = "224.0.23.5"
+
 TRACKER = os.environ.get("OPENTRACKER", os.path.join(os.path.dirname(__file__), "..", "..", "opentracker.debug"))
 
 
@@ -76,6 +79,9 @@ class Tracker:
 
     def __init__(self, extra_config="", files=None):
         self.port = free_port()
+        # Only used by a config that asks for live sync, but allocated either
+        # way so {livesync_port} always resolves.
+        self.livesync_port = free_port()
         self.dir = tempfile.mkdtemp(prefix="ot-integration-")
         self.log = None
         self.process = None
@@ -87,7 +93,7 @@ class Tracker:
             with open(self.config, "w") as handle:
                 handle.write("listen.tcp 127.0.0.1:%d\n" % self.port)
                 handle.write("listen.udp 127.0.0.1:%d\n" % self.port)
-                handle.write(extra_config.replace("{dir}", self.dir))
+                handle.write(extra_config.replace("{dir}", self.dir).replace("{livesync_port}", str(self.livesync_port)))
             self.log = open(os.path.join(self.dir, "tracker.log"), "w+b")
             # Leak detection is left at the sanitizer's own default, which is on
             # where LeakSanitizer exists and off where it does not. Asking for it
@@ -186,6 +192,32 @@ class Tracker:
     def torrent_count(self):
         return int(self.stats("torr").split()[0])
 
+    def livesync_send(self, payload):
+        """Put a packet on the live sync group.
+
+        It has to go to the group rather than straight at the port: the
+        tracker binds two sockets there, the reader on the wildcard address
+        and the writer on the configured one, and the kernel gives a unicast
+        datagram to the more specific of the two, which nobody reads."""
+        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        try:
+            sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_IF, socket.inet_aton("127.0.0.1"))
+            sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 1)
+            sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 1)
+            sock.sendto(payload, (LIVESYNC_GROUP, self.livesync_port))
+        finally:
+            sock.close()
+
+    def wait_until(self, predicate, timeout=5):
+        """A live sync packet is handled by another thread, so an effect of
+        one arrives some time after the send."""
+        deadline = time.time() + timeout
+        while time.time() < deadline:
+            if predicate():
+                return True
+            time.sleep(0.02)
+        return predicate()
+
     # ------------------------------------------------------------ over udp
 
     def udp_connect(self):