https://en.bitcoin.it/w/api.php?action=feedcontributions&feedformat=atom&user=UbcBitcoin Wiki - User contributions [en]2026-04-17T00:34:28ZUser contributionsMediaWiki 1.43.8https://en.bitcoin.it/w/index.php?title=Satoshi_Client_Transaction_Exchange&diff=19310Satoshi Client Transaction Exchange2011-11-13T05:54:02Z<p>Ubc: /* Wallet Send */ spelling correction</p>
<hr />
<div>==Overview==<br />
<br />
The Satoshi client advertises locally generated transactions and relays<br />
transactions from other nodes. This article describes the operations<br />
that deal with this exchange of transactions.<br />
<br />
See this article for more information on how transactions are validated:<br />
[https://en.bitcoin.it/wiki/Protocol_rules#.22tx.22_messages Protocol Rules]<br />
<br />
<br />
== Wallet Send ==<br />
<br />
The client periodically calls SendMessages() (in main.cpp) which calls<br />
ResendWalletTransactions to send transactions generated locally.<br />
This routine looks to see if there has been a new block since last time,<br />
and if so, and the local transaction are still not in a block,<br />
then the transactions are sent to all nodes.<br />
This is done only about every 30 minutes.<br />
<br />
Transactions are only rebroadcast if they have a timestamp at least<br />
5 minutes older than the last block was received. They are sorted<br />
and sent oldest first.[1]<br />
<br />
== Periodic Advertisement ==<br />
<br />
The client periodically calls SendMessages() (in main.cpp) which<br />
determines if a message should be sent to a remote node.<br />
For each message processing iteration, one node is chosen as the<br />
"trickle node".[2] This node is the only one chosen to receive<br />
an "addr" message, if appropriate.[3]<br />
<br />
In the section for inventory, the client sends 1/4 of the transaction<br />
inventory, determined randomly [4], UNLESS they are the trickle node,<br />
in which case they receive ALL transactions.[5] Yes that seems reversed,<br />
but it is what it is. If the node is to receive 1/4 (not all), then the<br />
code also avoids sending any transactions that came from the local<br />
wallet.[6] The comments indicate this is intended to increase privacy.<br />
<br />
<br />
<br />
== Relay ==<br />
<br />
When the client receives a transaction via a "tx" messages,<br />
it calls RelayMessage, which calls RelayInventory, which queues the<br />
inventory to be sent to all other nodes.[7]<br />
<br />
<br />
<br />
==Footnotes==<br />
<br />
1. See CWallet::ResendWalletTransactions in wallet.cpp.<br />
<br />
2. See:<br />
pnodeTrickle = vNodesCopy[GetRand(vNodesCopy.size())];<br />
and<br />
SendMessages(pnode, pnode == pnodeTrickle);<br />
in ThreadMessageHandler2() in net.cpp.<br />
<br />
3. See:<br />
//<br />
// Message: addr<br />
//<br />
if (fSendTrickle)<br />
{ <br />
in SendMessages() in main.cpp.<br />
<br />
4. See:<br />
bool fTrickleWait = ((hashRand & 3) != 0);<br />
in SendMessages() in main.cpp.<br />
<br />
5. See:<br />
// trickle out tx inv to protect privacy<br />
if (inv.type == MSG_TX && !fSendTrickle)<br />
{ <br />
in SendMessages() in main.cpp.<br />
<br />
6. See:<br />
// always trickle our own transactions<br />
if (!fTrickleWait)<br />
{ <br />
CWalletTx wtx;<br />
if (GetTransaction(inv.hash, wtx))<br />
if (wtx.fFromMe)<br />
fTrickleWait = true;<br />
}<br />
in SendMessages() in main.cpp.<br />
<br />
7. Both RelayMessage and RelayInventory in net.h.<br />
<br />
<br />
[[Category:Developer]]<br />
[[Category:Technical]]</div>Ubc