test: Combine addr generation helper functions

This combines the addr generation helper functions setup_addr_msg
and setup_rand_addr_msg.
It also changes the way addr.time is filled to random, because before,
if too many addresses (>600) were created in a batch, they would stop
being relayed because their timestamp would be too far in the future.

test/functional/p2p_addr_relay.py

@@ -44,7 +44,7 @@ class AddrReceiver(P2PInterface):
                 assert_equal(addr.nServices, 9)
                 if not 8333 <= addr.port < 8343:
                     raise AssertionError("Invalid addr.port of {} (8333-8342 expected)".format(addr.port))
-                assert addr.ip.startswith('123.123.123.')
+                assert addr.ip.startswith('123.123.')
 
     def on_getaddr(self, message):
         # When the node sends us a getaddr, it increments the addr relay tokens for the connection by 1000
@@ -91,30 +91,21 @@ class AddrTest(BitcoinTestFramework):
         self.blocksonly_mode_tests()
         self.rate_limit_tests()
 
-    def setup_addr_msg(self, num):
+    def setup_addr_msg(self, num, sequential_ips=True):
         addrs = []
         for i in range(num):
             addr = CAddress()
-            addr.time = self.mocktime + i
+            addr.time = self.mocktime + random.randrange(-100, 100)
             addr.nServices = P2P_SERVICES
-            addr.ip = f"123.123.123.{self.counter % 256}"
+            if sequential_ips:
+                assert self.counter < 256 ** 2  # Don't allow the returned ip addresses to wrap.
+                addr.ip = f"123.123.{self.counter // 256}.{self.counter % 256}"
+                self.counter += 1
+            else:
+                addr.ip = f"{random.randrange(128,169)}.{random.randrange(1,255)}.{random.randrange(1,255)}.{random.randrange(1,255)}"
             addr.port = 8333 + i
             addrs.append(addr)
-            self.counter += 1
-
-        msg = msg_addr()
-        msg.addrs = addrs
-        return msg
 
-    def setup_rand_addr_msg(self, num):
-        addrs = []
-        for i in range(num):
-            addr = CAddress()
-            addr.time = self.mocktime + i
-            addr.nServices = P2P_SERVICES
-            addr.ip = f"{random.randrange(128,169)}.{random.randrange(1,255)}.{random.randrange(1,255)}.{random.randrange(1,255)}"
-            addr.port = 8333
-            addrs.append(addr)
         msg = msg_addr()
         msg.addrs = addrs
         return msg
@@ -317,7 +308,7 @@ class AddrTest(BitcoinTestFramework):
     def send_addrs_and_test_rate_limiting(self, peer, no_relay, *, new_addrs, total_addrs):
         """Send an addr message and check that the number of addresses processed and rate-limited is as expected"""
 
-        peer.send_and_ping(self.setup_rand_addr_msg(new_addrs))
+        peer.send_and_ping(self.setup_addr_msg(new_addrs, sequential_ips=False))
 
         peerinfo = self.nodes[0].getpeerinfo()[0]
         addrs_processed = peerinfo['addr_processed']