From 34bed0ed8c449a3834927cec3447dbe6c74edf3d Mon Sep 17 00:00:00 2001
From: woltx <94266259+w0xlt@users.noreply.github.com>
Date: Mon, 19 Jan 2026 01:53:40 -0800
Subject: [PATCH] test: use IP_PORTRANGE_HIGH on FreeBSD for dynamic port
 allocation

On FreeBSD, the default ephemeral port range (10000-65535) overlaps
with the test framework's static port range (11000-26000), causing
intermittent "address already in use" failures when tests use dynamic
port allocation (port=0).

Add a helper function that sets the IP_PORTRANGE/IPV6_PORTRANGE socket
option to IP_PORTRANGE_HIGH before binding, which requests ports from
the high range (49152-65535) instead. This range does not overlap with
the test framework's static ports.

Constants from FreeBSD's netinet/in.h and netinet6/in6.h:
- IP_PORTRANGE = 19 (for IPv4 sockets)
- IPV6_PORTRANGE = 14 (for IPv6 sockets)
- IP_PORTRANGE_HIGH = 1

Fixes: bitcoin/bitcoin#34331

Co-Authored-By: Vasil Dimov <vd@FreeBSD.org>
Co-Authored-By: MarcoFalke <*~=\`'#}+{/-|&$^_@721217.xyz>
---
 test/functional/test_framework/netutil.py | 19 +++++++++++++++++++
 test/functional/test_framework/socks5.py  |  7 ++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/test/functional/test_framework/netutil.py b/test/functional/test_framework/netutil.py
index 75577b0ca84..5504029a766 100644
--- a/test/functional/test_framework/netutil.py
+++ b/test/functional/test_framework/netutil.py
@@ -181,3 +181,22 @@ def format_addr_port(addr, port):
         return f"[{addr}]:{port}"
     else:
         return f"{addr}:{port}"
+
+
+def set_ephemeral_port_range(sock):
+    '''On FreeBSD, set socket to use the high ephemeral port range (49152-65535).
+
+    FreeBSD's default ephemeral port range (10000-65535) overlaps with the test
+    framework's static port range starting at TEST_RUNNER_PORT_MIN (default=11000).
+    Using IP_PORTRANGE_HIGH avoids this overlap when binding to port 0 for dynamic
+    port allocation.
+    '''
+    if sys.platform.startswith('freebsd'):
+        # Constants from FreeBSD's netinet/in.h and netinet6/in6.h
+        IP_PORTRANGE = 19
+        IPV6_PORTRANGE = 14
+        IP_PORTRANGE_HIGH = 1  # Same value for both IPv4 and IPv6
+        if sock.family == socket.AF_INET6:
+            sock.setsockopt(socket.IPPROTO_IPV6, IPV6_PORTRANGE, IP_PORTRANGE_HIGH)
+        else:
+            sock.setsockopt(socket.IPPROTO_IP, IP_PORTRANGE, IP_PORTRANGE_HIGH)
diff --git a/test/functional/test_framework/socks5.py b/test/functional/test_framework/socks5.py
index 711734cf98e..085c5a2e324 100644
--- a/test/functional/test_framework/socks5.py
+++ b/test/functional/test_framework/socks5.py
@@ -11,7 +11,8 @@ import queue
 import logging
 
 from .netutil import (
-    format_addr_port
+    format_addr_port,
+    set_ephemeral_port_range,
 )
 
 logger = logging.getLogger("TestFramework.socks5")
@@ -202,6 +203,10 @@ class Socks5Server():
         self.conf = conf
         self.s = socket.socket(conf.af)
         self.s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        # When using dynamic port allocation (port=0), ensure we don't get a
+        # port that conflicts with the test framework's static port range.
+        if conf.addr[1] == 0:
+            set_ephemeral_port_range(self.s)
         self.s.bind(conf.addr)
         # When port=0, the OS assigns an available port. Update conf.addr
         # to reflect the actual bound address so callers can use it.