connectd: don't be That Node when someone is gossipping crap.
What the developer wrote
Authored by Rusty Russell
connectd: don't be That Node when someone is gossipping crap.
As seen in my logs, we complain about nodes a *lot* (Hi old CLN!).
```
===>1589311 DEBUG 02e01367e1d7818a7e9a0e8a52badd5c32615e07568dbe0497b6a47f9bef89d6af-connectd: peer_out WIRE_WARNING
139993 DEBUG lightningd: fixup_scan: block 786151 with 1203 txs
55388 DEBUG plugin-bcli: Log pruned 1001 entries (mem 10508118 -> 10298662)
33000 DEBUG gossipd: Unreasonable timestamp in 0102000a38ec41f9137a5a560dac6effbde059c12cb727344821cbdd4ef46964a4791a0f67cd997499a6062fc8b4284bf1b47a91541fd0e65129505f02e4d08542b16fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d61900000000000d9d56000ba40001690fe262010100900000000000000001000003e8000001f30000000000989680
23515 DEBUG hsmd: Client: Received message 14 from client
22269 DEBUG 024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605-hsmd: Got WIRE_HSMD_ECDH_REQ
14409 DEBUG gossipd: Enqueueing update for announce 0102002f7e4b4deb19947c67292e70cb22f7fac837fa9ee6269393f3c513d0431d52672e7387625856c19299cfd584e1a3f39e0f98df13c99090df9f4d5cca8446776fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d61900000000000e216b0008050001692e1c390101009000000000000003e800000000000013880000004526945a00
12534 DEBUG gossipd: Previously-rejected announce for 514127x248x1
10761 DEBUG 02e01367e1d7818a7e9a0e8a52badd5c32615e07568dbe0497b6a47f9bef89d6af-channeld-chan#70770: Got it!
10761 DEBUG 02e01367e1d7818a7e9a0e8a52badd5c32615e07568dbe0497b6a47f9bef89d6af-channeld-chan#70770: ... , awaiting 1120
10761 DEBUG 02e01367e1d7818a7e9a0e8a52badd5c32615e07568dbe0497b6a47f9bef89d6af-channeld-chan#70770: Sending master 1020
```
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
What changed, and why it matters
This change is a minor log/noise reduction fix. When a peer sends a channel announcement for a channel whose funding transaction output has already been spent, the node used to send a warning message back every single time. Now it sends that warning at most once per second. The old behavior could annoy or overload peers (especially older CLN versions that keep sending stale announcements), but it does not create a direct security vulnerability like theft or remote crash.
No urgent action. Treat as routine maintenance. Operators may notice reduced warning log volume from peers running old CLN versions.
Security signals we found
Rate-limiting of peer warning messages
Log/DoS noise reduction from stale gossip
No cryptographic or authorization change
Evidence from the diff
In gossipd/gossmap_manage.c, the handler for a channel_announcement with an already-spent UTXO (tal_count(outscript) == 0) previously called peer_warning() unconditionally. The patch adds a one-second rate limit using a static timemono variable, so peer_warning() is only emitted if more than one second has passed since the last warning. This addresses observed log spam from pre-25.12 CLN nodes that gossip stale channel announcements. The functional handling of the bad announcement (goto bad) is unchanged.
Changed components
gossipd/gossmap_manage.cconnectd peer warning pathInspect captured patch +10 / −3
diff --git a/gossipd/gossmap_manage.c b/gossipd/gossmap_manage.c
index c0589148..556104c7 100644
--- a/gossipd/gossmap_manage.c
+++ b/gossipd/gossmap_manage.c
@@ -703,9 +703,16 @@ void gossmap_manage_handle_get_txout_reply(struct gossmap_manage *gm, const u8 *
* - MUST ignore the message.
*/
if (tal_count(outscript) == 0) {
- peer_warning(gm, pca->source_peer,
- "channel_announcement: no unspent txout %s",
- fmt_short_channel_id(tmpctx, scid));
+ /* Don't flood them: this happens with pre-25.12 CLN
+ * nodes, which lost their marbles about some old
+ * UTXOs. */
+ static struct timemono prev;
+ if (time_greater(timemono_since(prev), time_from_sec(1))) {
+ peer_warning(gm, pca->source_peer,
+ "channel_announcement: no unspent txout %s",
+ fmt_short_channel_id(tmpctx, scid));
+ prev = time_mono();
+ }
goto bad;
}
Why this scored 23/100
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