Method HandlePeerTest

libi2pd/SSU2Session.cpp:2458–2730

	}

	void SSU2Session::HandlePeerTest (const uint8_t * buf, size_t len)
	{
		// msgs 1-4
		if (len < 3) return;
		uint8_t msg = buf[0];
		size_t offset = 3; // points to signed data
		if (msg == 2 || msg == 4) offset += 32; // hash is presented for msg 2 and 4 only
		if (len < offset + 5) return;
		auto ts = i2p::util::GetMillisecondsSinceEpoch ();
		uint32_t nonce = bufbe32toh (buf + offset + 1);
		switch (msg) // msg
		{
			case 1: // Bob from Alice
			{
				auto session = m_Server.GetRandomPeerTestSession ((buf[12] == 6) ? i2p::data::RouterInfo::eSSU2V4 : i2p::data::RouterInfo::eSSU2V6,
					GetRemoteIdentity ()->GetIdentHash ());
				if (session) // session with Charlie
				{
					if (m_Server.AddPeerTest (nonce, shared_from_this (), ts/1000))
					{
						auto packet = m_Server.GetSentPacketsPool ().AcquireShared ();
						// Alice's RouterInfo
						auto r = i2p::data::netdb.FindRouter (GetRemoteIdentity ()->GetIdentHash ());
						if (r && (r->IsUnreachable () || !i2p::data::netdb.PopulateRouterInfoBuffer (r))) r = nullptr;
						packet->payloadSize = r ? CreateRouterInfoBlock (packet->payload, m_MaxPayloadSize - len - 32, r) : 0;
						if (!packet->payloadSize && r)
							session->SendFragmentedMessage (CreateDatabaseStoreMsg (r));
						if (packet->payloadSize + len + 48 > m_MaxPayloadSize)
						{
							// doesn't fit one message, send RouterInfo in separate message
							uint32_t packetNum = session->SendData (packet->payload, packet->payloadSize, SSU2_FLAG_IMMEDIATE_ACK_REQUESTED);
							packet->sendTime = ts;
							session->m_SentPackets.emplace (packetNum, packet);
							packet = m_Server.GetSentPacketsPool ().AcquireShared (); // new packet
						}
						// PeerTest to Charlie
						packet->payloadSize += CreatePeerTestBlock (packet->payload + packet->payloadSize, m_MaxPayloadSize - packet->payloadSize, 2,
							eSSU2PeerTestCodeAccept, GetRemoteIdentity ()->GetIdentHash (), buf + offset, len - offset);
						packet->payloadSize += CreatePaddingBlock (packet->payload + packet->payloadSize, m_MaxPayloadSize - packet->payloadSize);
						uint32_t packetNum = session->SendData (packet->payload, packet->payloadSize, SSU2_FLAG_IMMEDIATE_ACK_REQUESTED);
						packet->sendTime = ts;
						session->m_SentPackets.emplace (packetNum, packet);
					}
					else
						LogPrint (eLogInfo, "SSU2: Peer test 1 nonce ", nonce, " already exists. Ignored");
				}
				else
				{
					// Charlie not found, send error back to Alice
					auto packet = m_Server.GetSentPacketsPool ().AcquireShared ();
					uint8_t zeroHash[32] = {0};
					packet->payloadSize = CreatePeerTestBlock (packet->payload, m_MaxPayloadSize, 4,
						eSSU2PeerTestCodeBobNoCharlieAvailable, zeroHash, buf + offset, len - offset);
					packet->payloadSize += CreatePaddingBlock (packet->payload + packet->payloadSize, m_MaxPayloadSize - packet->payloadSize);
					uint32_t packetNum = SendData (packet->payload, packet->payloadSize);
					packet->sendTime = ts;
					m_SentPackets.emplace (packetNum, packet);
				}