test: use IP_PORTRANGE_HIGH on FreeBSD for dynamic port allocation #34336

1. 
   w0xlt commented at 10:32 am on January 19, 2026: contributor

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

   This PR adds a helper that sets IP_PORTRANGE_HIGH via setsockopt() before binding, requesting ports from 49152-65535 instead, which avoids the overlap, as suggested in #34331 (comment) by @maflcko .

   From FreeBSD’s sys/netinet/in.h:

   0#define IP_PORTRANGE         19
   1#define IP_PORTRANGE_HIGH    1
   2#define IPPORT_EPHEMERALFIRST 10000  /* default range start */
   3#define IPPORT_HIFIRSTAUTO   49152   /* high range start */
   

   See also: FreeBSD https://man.freebsd.org/cgi/man.cgi?query=ip&sektion=4 man page.

   I’ll leave the PR as a draft since I haven’t tested it on FreeBSD yet and would like to gather feedback on the approach.

   Fixes #34331

2. 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 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:
   - IP_PORTRANGE = 19
   - IP_PORTRANGE_HIGH = 1
   
   Fixes: bitcoin/bitcoin#34331
   
   Co-Authored-By: MarcoFalke <*~=\`'#}+{/-|&$^_@721217.xyz>

   d73b792c5b
3. DrahtBot added the label Tests on Jan 19, 2026
4. 
   DrahtBot commented at 10:32 am on January 19, 2026: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/34336.

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5. w0xlt marked this as a draft on Jan 19, 2026
6. 
   hebasto commented at 10:40 am on January 19, 2026: member

   cc @vasild
7. 
   vasild commented at 2:37 pm on January 19, 2026: contributor

   0    sock.setsockopt(socket.IPPROTO_IP, IP_PORTRANGE, IP_PORTRANGE_HIGH)
   1    ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   2OSError: [Errno 22] Invalid argument
   

   It is possible to configure the port range system-wide with, e.g.:

   0root# sysctl net.inet.ip.portrange.first=32768
   

8. w0xlt closed this on Jan 19, 2026

   ---

9. w0xlt deleted the branch on Jan 19, 2026
10. 
    vasild commented at 3:08 pm on January 19, 2026: contributor

    This works and has the intended effect, from a C++ program:

    0    int val{IP_PORTRANGE_HIGH};
    1    setsockopt(s, IPPROTO_IP, IP_PORTRANGE, &val, sizeof(val));
    

11. w0xlt restored the branch on Jan 19, 2026
12. 
    w0xlt commented at 5:47 pm on January 19, 2026: contributor

    Reopening. I’ve now tested it on FreeBSD and it works.
13. 
    w0xlt commented at 5:56 pm on January 19, 2026: contributor

    The issue was caused by feature_proxy.py using IPv6 sockets. On FreeBSD, IPv6 requires IPV6_PORTRANGE with IPPROTO_IPV6.

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w0xlt DrahtBot hebasto vasild

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