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Backport Bitcoin PR#8113: Rework addnode behaviour (#1525)
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* Rework addnode behaviour

* Use CNode::addeName to track whether a connection to a name is already open
  * A new connection to a previously-connected by-name addednode is only opened when
    the previous one closes (even if the name starts resolving to something else)
  * At most one connection is opened per addednode (even if the name resolves to multiple)
* Unify the code between ThreadOpenAddedNodeConnections and getaddednodeinfo
  * Information about open connections is always returned, and the dns argument becomes a dummy
  * An IP address and inbound/outbound is only reported for the (at most 1) open connection

* Prevent duplicate connections where one is by name and another by ip

* Randomize name lookup result in ConnectSocketByName
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OlegGirko authored and UdjinM6 committed Jul 14, 2017
1 parent 1b1d52a commit 9ce2b96
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Showing 4 changed files with 122 additions and 124 deletions.
132 changes: 84 additions & 48 deletions src/net.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -420,6 +420,31 @@ CNode* ConnectNode(CAddress addrConnect, const char *pszDest, bool fConnectToMas
return NULL;
}

if (pszDest && addrConnect.IsValid()) {
// It is possible that we already have a connection to the IP/port pszDest resolved to.
// In that case, drop the connection that was just created, and return the existing CNode instead.
// Also store the name we used to connect in that CNode, so that future FindNode() calls to that
// name catch this early.
CNode* pnode = FindNode((CService)addrConnect);
if (pnode)
{
// we have existing connection to this node but it was not a connection to masternode,
// change flag and add reference so that we can correctly clear it later
if(fConnectToMasternode && !pnode->fMasternode) {
pnode->AddRef();
pnode->fMasternode = true;
}
{
LOCK(cs_vNodes);
if (pnode->addrName.empty()) {
pnode->addrName = std::string(pszDest);
}
}
CloseSocket(hSocket);
return pnode;
}
}

addrman.Attempt(addrConnect);

// Add node
Expand Down Expand Up @@ -1682,68 +1707,79 @@ void ThreadOpenConnections()
}
}

void ThreadOpenAddedConnections()
std::vector<AddedNodeInfo> GetAddedNodeInfo()
{
std::vector<AddedNodeInfo> ret;

std::list<std::string> lAddresses(0);
{
LOCK(cs_vAddedNodes);
vAddedNodes = mapMultiArgs["-addnode"];
ret.reserve(vAddedNodes.size());
BOOST_FOREACH(const std::string& strAddNode, vAddedNodes)
lAddresses.push_back(strAddNode);
}

if (HaveNameProxy()) {
while(true) {
std::list<std::string> lAddresses(0);
{
LOCK(cs_vAddedNodes);
BOOST_FOREACH(const std::string& strAddNode, vAddedNodes)
lAddresses.push_back(strAddNode);

// Build a map of all already connected addresses (by IP:port and by name) to inbound/outbound and resolved CService
std::map<CService, bool> mapConnected;
std::map<std::string, std::pair<bool, CService>> mapConnectedByName;
{
LOCK(cs_vNodes);
for (const CNode* pnode : vNodes) {
if (pnode->addr.IsValid()) {
mapConnected[pnode->addr] = pnode->fInbound;
}
BOOST_FOREACH(const std::string& strAddNode, lAddresses) {
CAddress addr;
CSemaphoreGrant grant(*semOutbound);
OpenNetworkConnection(addr, &grant, strAddNode.c_str());
MilliSleep(500);
if (!pnode->addrName.empty()) {
mapConnectedByName[pnode->addrName] = std::make_pair(pnode->fInbound, static_cast<const CService&>(pnode->addr));
}
}
}

BOOST_FOREACH(const std::string& strAddNode, lAddresses) {
CService service(strAddNode, Params().GetDefaultPort());
if (service.IsValid()) {
// strAddNode is an IP:port
auto it = mapConnected.find(service);
if (it != mapConnected.end()) {
ret.push_back(AddedNodeInfo{strAddNode, service, true, it->second});
} else {
ret.push_back(AddedNodeInfo{strAddNode, CService(), false, false});
}
} else {
// strAddNode is a name
auto it = mapConnectedByName.find(strAddNode);
if (it != mapConnectedByName.end()) {
ret.push_back(AddedNodeInfo{strAddNode, it->second.second, true, it->second.first});
} else {
ret.push_back(AddedNodeInfo{strAddNode, CService(), false, false});
}
MilliSleep(120000); // Retry every 2 minutes
}
}

return ret;
}

void ThreadOpenAddedConnections()
{
{
LOCK(cs_vAddedNodes);
vAddedNodes = mapMultiArgs["-addnode"];
}

for (unsigned int i = 0; true; i++)
{
std::list<std::string> lAddresses(0);
{
LOCK(cs_vAddedNodes);
BOOST_FOREACH(const std::string& strAddNode, vAddedNodes)
lAddresses.push_back(strAddNode);
std::vector<AddedNodeInfo> vInfo = GetAddedNodeInfo();
for (const AddedNodeInfo& info : vInfo) {
if (!info.fConnected) {
CSemaphoreGrant grant(*semOutbound);
// If strAddedNode is an IP/port, decode it immediately, so
// OpenNetworkConnection can detect existing connections to that IP/port.
CService service(info.strAddedNode, Params().GetDefaultPort());
OpenNetworkConnection(CAddress(service, NODE_NONE), &grant, info.strAddedNode.c_str(), false);
MilliSleep(500);
}
}

std::list<std::vector<CService> > lservAddressesToAdd(0);
BOOST_FOREACH(const std::string& strAddNode, lAddresses) {
std::vector<CService> vservNode(0);
if(Lookup(strAddNode.c_str(), vservNode, Params().GetDefaultPort(), fNameLookup, 0))
lservAddressesToAdd.push_back(vservNode);
}
// Attempt to connect to each IP for each addnode entry until at least one is successful per addnode entry
// (keeping in mind that addnode entries can have many IPs if fNameLookup)
{
LOCK(cs_vNodes);
BOOST_FOREACH(CNode* pnode, vNodes)
for (std::list<std::vector<CService> >::iterator it = lservAddressesToAdd.begin(); it != lservAddressesToAdd.end(); it++)
BOOST_FOREACH(const CService& addrNode, *(it))
if (pnode->addr == addrNode)
{
it = lservAddressesToAdd.erase(it);
it--;
break;
}
}
BOOST_FOREACH(std::vector<CService>& vserv, lservAddressesToAdd)
{
CSemaphoreGrant grant(*semOutbound);
/* We want -addnode to work even for nodes that don't provide all
* wanted services, so pass in nServices=NODE_NONE to CAddress. */
OpenNetworkConnection(CAddress(vserv[i % vserv.size()], NODE_NONE), &grant);
MilliSleep(500);
}
MilliSleep(120000); // Retry every 2 minutes
}
}
Expand Down
10 changes: 10 additions & 0 deletions src/net.h
Original file line number Diff line number Diff line change
Expand Up @@ -886,4 +886,14 @@ std::vector<CNode*> CopyNodeVector();

void ReleaseNodeVector(const std::vector<CNode*>& vecNodes);

struct AddedNodeInfo
{
std::string strAddedNode;
CService resolvedAddress;
bool fConnected;
bool fInbound;
};

std::vector<AddedNodeInfo> GetAddedNodeInfo();

#endif // BITCOIN_NET_H
10 changes: 6 additions & 4 deletions src/netbase.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -613,10 +613,12 @@ bool ConnectSocketByName(CService &addr, SOCKET& hSocketRet, const char *pszDest
proxyType nameProxy;
GetNameProxy(nameProxy);

CService addrResolved(CNetAddr(strDest, fNameLookup && !HaveNameProxy()), port);
if (addrResolved.IsValid()) {
addr = addrResolved;
return ConnectSocket(addr, hSocketRet, nTimeout);
std::vector<CService> addrResolved;
if (Lookup(strDest.c_str(), addrResolved, port, fNameLookup && !HaveNameProxy(), 256)) {
if (addrResolved.size() > 0) {
addr = addrResolved[GetRand(addrResolved.size())];
return ConnectSocket(addr, hSocketRet, nTimeout);
}
}

addr = CService("0.0.0.0:0");
Expand Down
94 changes: 22 additions & 72 deletions src/rpc/net.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -270,25 +270,22 @@ UniValue getaddednodeinfo(const UniValue& params, bool fHelp)
{
if (fHelp || params.size() < 1 || params.size() > 2)
throw runtime_error(
"getaddednodeinfo dns ( \"node\" )\n"
"getaddednodeinfo dummy ( \"node\" )\n"
"\nReturns information about the given added node, or all added nodes\n"
"(note that onetry addnodes are not listed here)\n"
"If dns is false, only a list of added nodes will be provided,\n"
"otherwise connected information will also be available.\n"
"\nArguments:\n"
"1. dns (boolean, required) If false, only a list of added nodes will be provided, otherwise connected information will also be available.\n"
"1. dummy (boolean, required) Kept for historical purposes but ignored\n"
"2. \"node\" (string, optional) If provided, return information about this specific node, otherwise all nodes are returned.\n"
"\nResult:\n"
"[\n"
" {\n"
" \"addednode\" : \"192.168.0.201\", (string) The node ip address\n"
" \"addednode\" : \"192.168.0.201\", (string) The node ip address or name (as provided to addnode)\n"
" \"connected\" : true|false, (boolean) If connected\n"
" \"addresses\" : [\n"
" \"addresses\" : [ (list of objects) Only when connected = true\n"
" {\n"
" \"address\" : \"192.168.0.201:9999\", (string) The dash server host and port\n"
" \"address\" : \"192.168.0.201:9999\", (string) The dash server IP and port we're connected to\n"
" \"connected\" : \"outbound\" (string) connection, inbound or outbound\n"
" }\n"
" ,...\n"
" ]\n"
" }\n"
" ,...\n"
Expand All @@ -299,82 +296,35 @@ UniValue getaddednodeinfo(const UniValue& params, bool fHelp)
+ HelpExampleRpc("getaddednodeinfo", "true, \"192.168.0.201\"")
);

bool fDns = params[0].get_bool();
std::vector<AddedNodeInfo> vInfo = GetAddedNodeInfo();

list<string> laddedNodes(0);
if (params.size() == 1)
{
LOCK(cs_vAddedNodes);
BOOST_FOREACH(const std::string& strAddNode, vAddedNodes)
laddedNodes.push_back(strAddNode);
}
else
{
string strNode = params[1].get_str();
LOCK(cs_vAddedNodes);
BOOST_FOREACH(const std::string& strAddNode, vAddedNodes) {
if (strAddNode == strNode)
{
laddedNodes.push_back(strAddNode);
if (params.size() == 2) {
bool found = false;
for (const AddedNodeInfo& info : vInfo) {
if (info.strAddedNode == params[1].get_str()) {
vInfo.assign(1, info);
found = true;
break;
}
}
if (laddedNodes.size() == 0)
if (!found) {
throw JSONRPCError(RPC_CLIENT_NODE_NOT_ADDED, "Error: Node has not been added.");
}

UniValue ret(UniValue::VARR);
if (!fDns)
{
BOOST_FOREACH (const std::string& strAddNode, laddedNodes) {
UniValue obj(UniValue::VOBJ);
obj.push_back(Pair("addednode", strAddNode));
ret.push_back(obj);
}
return ret;
}

list<pair<string, vector<CService> > > laddedAddreses(0);
BOOST_FOREACH(const std::string& strAddNode, laddedNodes) {
vector<CService> vservNode(0);
if(Lookup(strAddNode.c_str(), vservNode, Params().GetDefaultPort(), fNameLookup, 0))
laddedAddreses.push_back(make_pair(strAddNode, vservNode));
else
{
UniValue obj(UniValue::VOBJ);
obj.push_back(Pair("addednode", strAddNode));
obj.push_back(Pair("connected", false));
UniValue addresses(UniValue::VARR);
obj.push_back(Pair("addresses", addresses));
}
}
UniValue ret(UniValue::VARR);

LOCK(cs_vNodes);
for (list<pair<string, vector<CService> > >::iterator it = laddedAddreses.begin(); it != laddedAddreses.end(); it++)
{
for (const AddedNodeInfo& info : vInfo) {
UniValue obj(UniValue::VOBJ);
obj.push_back(Pair("addednode", it->first));

obj.push_back(Pair("addednode", info.strAddedNode));
obj.push_back(Pair("connected", info.fConnected));
UniValue addresses(UniValue::VARR);
bool fConnected = false;
BOOST_FOREACH(const CService& addrNode, it->second) {
bool fFound = false;
UniValue node(UniValue::VOBJ);
node.push_back(Pair("address", addrNode.ToString()));
BOOST_FOREACH(CNode* pnode, vNodes) {
if (pnode->addr == addrNode)
{
fFound = true;
fConnected = true;
node.push_back(Pair("connected", pnode->fInbound ? "inbound" : "outbound"));
break;
}
}
if (!fFound)
node.push_back(Pair("connected", "false"));
addresses.push_back(node);
if (info.fConnected) {
UniValue address(UniValue::VOBJ);
address.push_back(Pair("address", info.resolvedAddress.ToString()));
address.push_back(Pair("connected", info.fInbound ? "inbound" : "outbound"));
addresses.push_back(address);
}
obj.push_back(Pair("connected", fConnected));
obj.push_back(Pair("addresses", addresses));
ret.push_back(obj);
}
Expand Down

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