From 96a8e42bbc313f96d54377ae5886da84298e61a3 Mon Sep 17 00:00:00 2001 From: Bitflash Date: Wed, 29 Jul 2026 11:52:12 -0300 Subject: Remember .btf peers that answered, and dial them first on start (#25) * net: remember .btf peers that answered, and dial them first on start Discovery depends entirely on the Nostr relays. A node that has been up for hours knows exactly which peers respond, and throws all of it away on exit; the next start reaches for the relays again and walks the same descriptor list, of which roughly 96% is dead. That is what makes a restart take minutes before the first tunnel opens -- measured today at about seven. Every peer that completes a tunnel is now written to btfpeers.json with its meeting node and encryption key, which is everything needed to redial it. On start a thread tries those before the relays have answered anything, stopping once eight are connected. Entries older than a week are dropped, and the file holds at most fifty. Cache only: nothing here changes how a first-ever run bootstraps, and a missing or corrupt file just falls through to relay discovery. * net: exchange signed .btf descriptors between peers Discovery has depended entirely on the Nostr relays. Two connected nodes never told each other who else existed, so a relay outage left a running network unable to grow, and a node that found one stale peer had no way to learn there was anything better. The old `addr` gossip went out with the IRC seed. Peers now trade signed descriptors over a new "btfpeers" message: our own first, then peers that actually answered us. The receiver checks each Schnorr signature against the key the `.btf` address decodes to, so the sender is trusted for nothing -- forging an entry needs somebody else's secret key. That leaves flooding with self-generated keys, which the per-message caps and the "peers that answered" ordering are there to blunt. Unknown commands are ignored (main.cpp), so nodes without this just drop the message; nothing here is a protocol break. The cache from the peer-cache change now keeps each peer's descriptor verbatim alongside the parsed fields, because that signature is what makes a peer relayable. Entries without one -- resolved through Nostr, or written before this -- stay dialable, just not passed on. A dial never clears a descriptor already on file. * main_gui: implement /port, which net.cpp already documented net.cpp has said nListenPort is "tunable via /port" since it was written, but nothing ever parsed the option. Two nodes could not share a machine, which is exactly what testing peer exchange needs. Sets addrLocalHost.port too, so we do not advertise a port we never bound. --- src/main.cpp | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'src/main.cpp') diff --git a/src/main.cpp b/src/main.cpp index a75bf54..bb317d2 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -1877,6 +1877,14 @@ bool ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv) pfrom->PushMessage("getblocks", CBlockLocator(pindexBest), uint256(0)); } + // Introduce ourselves and hand over the .btf peers that answered us. + // Everything in here is self-certifying, so this is safe to send to a + // node we know nothing about, and safe for it to act on. + vector vPexOut; + BtfPexCollect(vPexOut); + if (!vPexOut.empty()) + pfrom->PushMessage("btfpeers", vPexOut); + if (LogAcceptsCategory("net")) printf("version addrMe = %s\n", addrMe.ToString().c_str()); } @@ -1888,6 +1896,29 @@ bool ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv) } + else if (strCommand == "btfpeers") + { + // Peer exchange. Nothing here is taken on trust: BtfPexAccept checks + // every descriptor's signature against the key its .btf address + // decodes to, and drops the rest. + int64 nNow = GetTime(); + if (nNow - pfrom->nLastPexRecv < PEX_MIN_INTERVAL) + { + if (LogAcceptsCategory("net")) + printf("btfpeers: ignoring, %s is sending them too fast\n", + pfrom->addr.ToString().c_str()); + return true; + } + pfrom->nLastPexRecv = nNow; + + vector vDesc; + vRecv >> vDesc; + int nKept = BtfPexAccept(vDesc); + LogPrint("net", "btfpeers: kept %d of %zu descriptor(s) from %s\n", + nKept, vDesc.size(), pfrom->addr.ToString().c_str()); + } + + else if (strCommand == "inv") { vector vInv; -- cgit v1.2.3