net: Add interrupt to pcp retry loop #33338

pull TheCharlatan wants to merge 1 commits into bitcoin:master from TheCharlatan:pcp_interrupt changing 5 files +36 −24
  1. TheCharlatan commented at 10:20 am on September 8, 2025: contributor
    Without this interrupt bitcoind takes a long time to exit if requested to do so after a failed pcp lookup on startup.
  2. net: Add interrupt to pcp retry loop 
    Without this interrupt bitcoind takes a long time to exit if requested
to do so after a failed pcp lookup on startup.
    188de70c86
  3. DrahtBot added the label P2P on Sep 8, 2025
  4. DrahtBot commented at 10:20 am on September 8, 2025: 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/33338.

    Reviews

    See the guideline for information on the review process.

    Type Reviewers
    ACK fjahr, hodlinator, achow101

    If your review is incorrectly listed, please react with 👎 to this comment and the bot will ignore it on the next update.

  5. TheCharlatan commented at 10:21 am on September 8, 2025: contributor

    Logs:

     02025-09-08T10:02:52Z msghand thread start
 12025-09-08T10:02:52Z Imported mempool transactions from file: 3 succeeded, 0 failed, 0 expired, 0 already there, 0 waiting for initial broadcast
 22025-09-08T10:02:52Z initload thread exit
 32025-09-08T10:02:52Z [net:warning] pcp: Could not receive response: Connection refused (111)
 42025-09-08T10:02:52Z [net] portmap: gateway [IPv6]: fe80::a6ce:daff:fe8f:12a0%4
 52025-09-08T10:02:52Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:4bfd:91da:7cba:67cb port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
 62025-09-08T10:02:52Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:4bfd:91da:7cba:67cb
 72025-09-08T10:02:53Z [net] trying v2 connection [2001:e60:1154:ccd9:3515:d56c:bb7:5f4c]:38333 lastseen=58.3hrs
 82025-09-08T10:02:53Z [net] pcp: Timeout
 92025-09-08T10:02:53Z [net] pcp: Retrying (1)
102025-09-08T10:02:54Z [net] pcp: Timeout
112025-09-08T10:02:54Z [net] pcp: Retrying (2)
12^C2025-09-08T10:02:54Z tor: Thread interrupt
132025-09-08T10:02:54Z Shutdown in progress...
142025-09-08T10:02:54Z torcontrol thread exit
152025-09-08T10:02:54Z dnsseed thread exit
162025-09-08T10:02:54Z addcon thread exit
172025-09-08T10:02:54Z net thread exit
182025-09-08T10:02:55Z msghand thread exit
192025-09-08T10:02:55Z [net] pcp: Timeout
202025-09-08T10:02:55Z [net] pcp: Giving up after 3 tries
212025-09-08T10:02:55Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:1386:bc1d:7d89:306d port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
222025-09-08T10:02:55Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:1386:bc1d:7d89:306d
232025-09-08T10:02:56Z [net] pcp: Timeout
242025-09-08T10:02:56Z [net] pcp: Retrying (1)
252025-09-08T10:02:57Z [net] pcp: Timeout
262025-09-08T10:02:57Z [net] pcp: Retrying (2)
272025-09-08T10:02:58Z [net] connection attempt to [2001:e60:1154:ccd9:3515:d56c:bb7:5f4c]:38333 timed out
282025-09-08T10:02:58Z opencon thread exit
292025-09-08T10:02:58Z [net] pcp: Timeout
302025-09-08T10:02:58Z [net] pcp: Giving up after 3 tries
312025-09-08T10:02:58Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:17ff:1c49:2591:5195 port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
322025-09-08T10:02:58Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:17ff:1c49:2591:5195
332025-09-08T10:02:59Z [net] pcp: Timeout
342025-09-08T10:02:59Z [net] pcp: Retrying (1)
352025-09-08T10:03:00Z [net] pcp: Timeout
362025-09-08T10:03:00Z [net] pcp: Retrying (2)
372025-09-08T10:03:01Z [net] pcp: Timeout
382025-09-08T10:03:01Z [net] pcp: Giving up after 3 tries
392025-09-08T10:03:01Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:5e43:d231:cd0b:5424 port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
402025-09-08T10:03:01Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:5e43:d231:cd0b:5424
412025-09-08T10:03:02Z [net] pcp: Timeout
422025-09-08T10:03:02Z [net] pcp: Retrying (1)
432025-09-08T10:03:03Z [net] pcp: Timeout
442025-09-08T10:03:03Z [net] pcp: Retrying (2)
452025-09-08T10:03:04Z [net] pcp: Timeout
462025-09-08T10:03:04Z [net] pcp: Giving up after 3 tries
472025-09-08T10:03:04Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:eb22:5bda:fe93:efb3 port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
482025-09-08T10:03:04Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:eb22:5bda:fe93:efb3
492025-09-08T10:03:05Z [net] pcp: Timeout
502025-09-08T10:03:05Z [net] pcp: Retrying (1)
512025-09-08T10:03:06Z [net] pcp: Timeout
522025-09-08T10:03:06Z [net] pcp: Retrying (2)
532025-09-08T10:03:07Z [net] pcp: Timeout
542025-09-08T10:03:07Z [net] pcp: Giving up after 3 tries
552025-09-08T10:03:07Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:ad0f:260a:2c63:7494 port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
562025-09-08T10:03:07Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:ad0f:260a:2c63:7494
572025-09-08T10:03:08Z [net] pcp: Timeout
582025-09-08T10:03:08Z [net] pcp: Retrying (1)
592025-09-08T10:03:09Z [net] pcp: Timeout
602025-09-08T10:03:09Z [net] pcp: Retrying (2)
612025-09-08T10:03:10Z [net] pcp: Timeout
622025-09-08T10:03:10Z [net] pcp: Giving up after 3 tries
632025-09-08T10:03:10Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:65cf:20cb:5921:45bf port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
642025-09-08T10:03:10Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:65cf:20cb:5921:45bf
652025-09-08T10:03:11Z [net] pcp: Timeout
662025-09-08T10:03:11Z [net] pcp: Retrying (1)
672025-09-08T10:03:12Z [net] pcp: Timeout
682025-09-08T10:03:12Z [net] pcp: Retrying (2)
692025-09-08T10:03:13Z [net] pcp: Timeout
702025-09-08T10:03:13Z [net] pcp: Giving up after 3 tries
712025-09-08T10:03:13Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:5f6b:1db9:7ba0:44a port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
722025-09-08T10:03:13Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:5f6b:1db9:7ba0:44a
732025-09-08T10:03:14Z [net] pcp: Timeout
742025-09-08T10:03:14Z [net] pcp: Retrying (1)
752025-09-08T10:03:15Z [net] pcp: Timeout
762025-09-08T10:03:15Z [net] pcp: Retrying (2)
772025-09-08T10:03:16Z [net] pcp: Timeout
782025-09-08T10:03:16Z [net] pcp: Giving up after 3 tries
792025-09-08T10:03:16Z [net] pcp: Requesting port mapping for addr 1111:1111::1 port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
802025-09-08T10:03:16Z [net] pcp: Internal address after connect: 1111:1111::1
812025-09-08T10:03:17Z [net] pcp: Timeout
822025-09-08T10:03:17Z [net] pcp: Retrying (1)
832025-09-08T10:03:18Z [net] pcp: Timeout
842025-09-08T10:03:18Z [net] pcp: Retrying (2)
852025-09-08T10:03:19Z [net] pcp: Timeout
862025-09-08T10:03:19Z [net] pcp: Giving up after 3 tries
872025-09-08T10:03:19Z mapport thread exit
882025-09-08T10:03:19Z [net] Flushed 13682 addresses to peers.dat  22ms
892025-09-08T10:03:19Z DumpAnchors: Flush 0 outbound block-relay-only peer addresses to anchors.dat started
902025-09-08T10:03:19Z DumpAnchors: Flush 0 outbound block-relay-only peer addresses to anchors.dat completed (0.01s)
912025-09-08T10:03:19Z scheduler thread exit
922025-09-08T10:03:19Z Writing 3 mempool transactions to file...
932025-09-08T10:03:19Z Writing 0 unbroadcast transactions to file.
942025-09-08T10:03:19Z Dumped mempool: 0.000s to copy, 0.008s to dump, 1011 bytes dumped to file
952025-09-08T10:03:19Z Flushed fee estimates to fee_estimates.dat.
962025-09-08T10:03:19Z Shutdown done

     02025-09-08T10:07:03Z msghand thread start
 12025-09-08T10:07:03Z addcon thread start
 22025-09-08T10:07:03Z initload thread exit
 32025-09-08T10:07:03Z [net:warning] pcp: Could not receive response: Connection refused (111)
 42025-09-08T10:07:03Z [net] portmap: gateway [IPv6]: fe80::a6ce:daff:fe8f:12a0%4
 52025-09-08T10:07:03Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:4bfd:91da:7cba:67cb port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
 62025-09-08T10:07:03Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:4bfd:91da:7cba:67cb
 7^C2025-09-08T10:07:03Z tor: Thread interrupt
 82025-09-08T10:07:03Z Shutdown in progress...
 92025-09-08T10:07:03Z torcontrol thread exit
102025-09-08T10:07:03Z addcon thread exit
112025-09-08T10:07:03Z opencon thread exit
122025-09-08T10:07:03Z dnsseed thread exit
132025-09-08T10:07:03Z net thread exit
142025-09-08T10:07:03Z msghand thread exit
152025-09-08T10:07:04Z [net] pcp: Timeout
162025-09-08T10:07:04Z [net] pcp: Retrying (1)
172025-09-08T10:07:04Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:1386:bc1d:7d89:306d port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
182025-09-08T10:07:04Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:1386:bc1d:7d89:306d
192025-09-08T10:07:04Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:17ff:1c49:2591:5195 port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
202025-09-08T10:07:04Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:17ff:1c49:2591:5195
212025-09-08T10:07:04Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:5e43:d231:cd0b:5424 port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
222025-09-08T10:07:04Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:5e43:d231:cd0b:5424
232025-09-08T10:07:04Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:eb22:5bda:fe93:efb3 port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
242025-09-08T10:07:04Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:eb22:5bda:fe93:efb3
252025-09-08T10:07:04Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:ad0f:260a:2c63:7494 port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
262025-09-08T10:07:04Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:ad0f:260a:2c63:7494
272025-09-08T10:07:04Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:65cf:20cb:5921:45bf port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
282025-09-08T10:07:04Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:65cf:20cb:5921:45bf
292025-09-08T10:07:04Z [net] pcp: Requesting port mapping for addr 2a02:1210:4a25:2f00:5f6b:1db9:7ba0:44a port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
302025-09-08T10:07:04Z [net] pcp: Internal address after connect: 2a02:1210:4a25:2f00:5f6b:1db9:7ba0:44a
312025-09-08T10:07:04Z [net] pcp: Requesting port mapping for addr 1111:1111::1 port 38333 from gateway fe80::a6ce:daff:fe8f:12a0%4
322025-09-08T10:07:04Z [net] pcp: Internal address after connect: 1111:1111::1
332025-09-08T10:07:04Z mapport thread exit
342025-09-08T10:07:04Z [net] Flushed 13692 addresses to peers.dat  20ms
352025-09-08T10:07:04Z DumpAnchors: Flush 0 outbound block-relay-only peer addresses to anchors.dat started
362025-09-08T10:07:04Z DumpAnchors: Flush 0 outbound block-relay-only peer addresses to anchors.dat completed (0.01s)
372025-09-08T10:07:04Z scheduler thread exit
382025-09-08T10:07:04Z Writing 3 mempool transactions to file...
392025-09-08T10:07:04Z Writing 0 unbroadcast transactions to file.
402025-09-08T10:07:04Z Dumped mempool: 0.000s to copy, 0.006s to dump, 1011 bytes dumped to file
412025-09-08T10:07:04Z Flushed fee estimates to fee_estimates.dat.
422025-09-08T10:07:04Z Shutdown done
  6. fanquake added this to the milestone 30.0 on Sep 8, 2025
  7. in src/common/pcp.cpp:222 in 188de70c86 
    217@@ -217,7 +218,8 @@ CNetAddr PCPUnwrapAddress(std::span<const uint8_t> wrapped_addr)
218 //! PCP or NAT-PMP send-receive loop.
219 std::optional<std::vector<uint8_t>> PCPSendRecv(Sock &sock, const std::string &protocol, std::span<const uint8_t> request, int num_tries,
220         std::chrono::milliseconds timeout_per_try,
221-        std::function<bool(std::span<const uint8_t>)> check_packet)
222+        std::function<bool(std::span<const uint8_t>)> check_packet,
223+        CThreadInterrupt& interrupt)
    hodlinator commented at 1:04 pm on September 8, 2025:

    nit: Would prefer keeping the lambda as the last parameter and also avoiding to mix &-placement within the same argument list.

    0        CThreadInterrupt &interrupt,
1        std::function<bool(std::span<const uint8_t>)> check_packet)
    fjahr commented at 7:29 pm on September 8, 2025:
    CThreadInterrupt& interrupt is our preferred style though (see PointerAlignment: Left in src/.clang-format), so maybe we rather want to fix the other parameter to keep it consistent.
  8. in src/common/pcp.cpp:243 in 188de70c86 
    239@@ -238,6 +240,7 @@ std::optional<std::vector<uint8_t>> PCPSendRecv(Sock &sock, const std::string &p
240         auto cur_time = time_point_cast<milliseconds>(MockableSteadyClock::now());
241         auto deadline = cur_time + timeout_per_try;
242         while ((cur_time = time_point_cast<milliseconds>(MockableSteadyClock::now())) < deadline) {
243+            if (interrupt) return std::nullopt;
    fjahr commented at 2:51 pm on September 8, 2025:
    nit: comment above lists all the conditions for the wait to exit so it should list interrupt as well.
  9. in src/test/pcp_tests.cpp:18 in 188de70c86 
    14@@ -15,6 +15,8 @@
15 
16 using namespace std::literals;
17 
18+static CThreadInterrupt g_interrupt;
    fjahr commented at 2:52 pm on September 8, 2025:
    nit: Could add a simple test where the interrupt is instantly called to make sure the line is covered somehow.
  10. fjahr commented at 2:54 pm on September 8, 2025: contributor

    utACK 188de70c86414b8b2ad5143f5c607b67686526ea

    Looks good to me, happy to re-review if you decide to address the nits.

  11. hodlinator approved
  12. hodlinator commented at 7:15 pm on September 8, 2025: contributor

    utACK 188de70c86414b8b2ad5143f5c607b67686526ea

    Change just passes down interrupt for checking in inner loops.

    Didn’t figure out a way of reproducing the behavior PR-author describes in #33338 (comment).

    • Wasn’t able to bring to (zombie) life a local IPv6 gateway.
    • Only have one ethernet interface on my local machine. Seems the author may have a handful.
    • Reproduced something similar anyway through hacking this in: 
       0diff --git a/src/common/pcp.cpp b/src/common/pcp.cpp
 1index ed6624cb89..33b4c653fa 100644
 2--- a/src/common/pcp.cpp
 3+++ b/src/common/pcp.cpp
 4@@ -246,9 +246,11 @@ std::optional<std::vector<uint8_t>> PCPSendRecv(Sock &sock, const std::string &p
 5                 LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "%s: Could not wait on socket: %s\n", protocol, NetworkErrorString(WSAGetLastError()));
 6                 return std::nullopt; // Network-level error, probably no use retrying.
 7             }
 8-            if (!occurred) {
 9+            std::this_thread::sleep_for(3s);
10+            //if (!occurred) {
11                 LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "%s: Timeout\n", protocol);
12                 break; // Retry.
13+            /*
14             }
15
16             // Receive response.
17@@ -263,6 +265,7 @@ std::optional<std::vector<uint8_t>> PCPSendRecv(Sock &sock, const std::string &p
18                 got_response = true; // Got expected response, break from receive loop as well as from retry loop.
19                 break;
20             }
21+            */
22         }
23     }
24     if (!got_response) {
      …and testing Ctrl+C with/without interrupt/PR.
  13. achow101 commented at 8:29 pm on September 8, 2025: member
    ACK 188de70c86414b8b2ad5143f5c607b67686526ea
  14. achow101 merged this on Sep 8, 2025
  15. achow101 closed this on Sep 8, 2025


TheCharlatan DrahtBot hodlinator fjahr achow101

Labels
P2P

Milestone
30.0

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