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Always use HELLO to contact, and we now confirm newly learned paths via a two-way handshake to prevent half-connects.

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This commit is contained in:
Adam Ierymenko 2015-04-07 12:22:33 -07:00
parent eae2c89b09
commit 24608d5ca3
3 changed files with 88 additions and 56 deletions
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89
node/Peer.cpp
View File

@ -25,6 +25,8 @@
* LLC. Start here: http://www.zerotier.com/
*/
#include "../version.h"
#include "Constants.hpp"
#include "Peer.hpp"
#include "Node.hpp"
@ -68,38 +70,48 @@ void Peer::received(
_lastReceive = now;
if (!hops) {
bool pathIsConfirmed = false;
/* Learn new paths from direct (hops == 0) packets */
{
unsigned int np = _numPaths;
bool havePath = false;
for(unsigned int p=0;p<np;++p) {
if (_paths[p].address() == remoteAddr) {
_paths[p].received(now,linkDesperation);
havePath = true;
pathIsConfirmed = true;
break;
}
}
if (!havePath) {
Path *slot = (Path *)0;
if (np < ZT_PEER_MAX_PATHS) {
// Add new path
slot = &(_paths[np++]);
} else {
// Replace oldest non-fixed path
uint64_t slotLRmin = 0xffffffffffffffffULL;
for(unsigned int p=0;p<ZT_PEER_MAX_PATHS;++p) {
if ((!_paths[p].fixed())&&(_paths[p].lastReceived() <= slotLRmin)) {
slotLRmin = _paths[p].lastReceived();
slot = &(_paths[p]);
if (!pathIsConfirmed) {
if ((verb == Packet::VERB_OK)&&(inReVerb == Packet::VERB_HELLO)) {
// Learn paths if they've been confirmed via a HELLO
Path *slot = (Path *)0;
if (np < ZT_PEER_MAX_PATHS) {
// Add new path
slot = &(_paths[np++]);
} else {
// Replace oldest non-fixed path
uint64_t slotLRmin = 0xffffffffffffffffULL;
for(unsigned int p=0;p<ZT_PEER_MAX_PATHS;++p) {
if ((!_paths[p].fixed())&&(_paths[p].lastReceived() <= slotLRmin)) {
slotLRmin = _paths[p].lastReceived();
slot = &(_paths[p]);
}
}
}
}
if (slot) {
slot->init(remoteAddr,false);
slot->received(now,linkDesperation);
_numPaths = np;
if (slot) {
slot->init(remoteAddr,false);
slot->received(now,linkDesperation);
_numPaths = np;
pathIsConfirmed = true;
}
} else {
/* If this path is not known, send a HELLO. We don't learn
* paths without confirming that a bidirectional link is in
* fact present, but any packet that decodes and authenticates
* correctly is considered valid. */
attemptToContactAt(RR,remoteAddr,linkDesperation,now);
}
}
}
@ -107,7 +119,7 @@ void Peer::received(
/* Announce multicast groups of interest to direct peers if they are
* considered authorized members of a given network. Also announce to
* supernodes and network controllers. */
if ((now - _lastAnnouncedTo) >= ((ZT_MULTICAST_LIKE_EXPIRE / 2) - 1000)) {
if ((pathIsConfirmed)&&((now - _lastAnnouncedTo) >= ((ZT_MULTICAST_LIKE_EXPIRE / 2) - 1000))) {
_lastAnnouncedTo = now;
const bool isSupernode = RR->topology->isSupernode(_id.address());
@ -144,6 +156,37 @@ void Peer::received(
_lastMulticastFrame = now;
}
void Peer::attemptToContactAt(const RuntimeEnvironment *RR,const InetAddress &atAddress,unsigned int linkDesperation,uint64_t now)
{
Packet outp(_id.address(),RR->identity.address(),Packet::VERB_HELLO);
outp.append((unsigned char)ZT_PROTO_VERSION);
outp.append((unsigned char)ZEROTIER_ONE_VERSION_MAJOR);
outp.append((unsigned char)ZEROTIER_ONE_VERSION_MINOR);
outp.append((uint16_t)ZEROTIER_ONE_VERSION_REVISION);
outp.append(now);
RR->identity.serialize(outp,false);
switch(atAddress.ss_family) {
case AF_INET:
outp.append((unsigned char)ZT_PROTO_DEST_ADDRESS_TYPE_IPV4);
outp.append(atAddress.rawIpData(),4);
outp.append((uint16_t)atAddress.port());
break;
case AF_INET6:
outp.append((unsigned char)ZT_PROTO_DEST_ADDRESS_TYPE_IPV6);
outp.append(atAddress.rawIpData(),16);
outp.append((uint16_t)atAddress.port());
break;
default:
outp.append((unsigned char)ZT_PROTO_DEST_ADDRESS_TYPE_NONE);
break;
}
outp.armor(_key,false); // HELLO is sent in the clear
RR->node->putPacket(atAddress,outp.data(),outp.size(),linkDesperation);
}
void Peer::addPath(const Path &newp)
{
unsigned int np = _numPaths;
@ -200,9 +243,7 @@ void Peer::resetWithinScope(const RuntimeEnvironment *RR,InetAddress::IpScope sc
while (x < np) {
if (_paths[x].address().ipScope() == scope) {
if (_paths[x].fixed()) {
Packet outp(_id.address(),RR->identity.address(),Packet::VERB_NOP);
outp.armor(_key,false);
RR->node->putPacket(_paths[x].address(),outp.data(),outp.size(),_paths[x].desperation(now));
attemptToContactAt(RR,_paths[x].address(),_paths[x].desperation(now),now);
_paths[y++] = _paths[x]; // keep fixed paths
}
} else {

13
node/Peer.hpp
View File

@ -169,6 +169,19 @@ public:
return (Path *)0;
}
/**
* Send a HELLO to this peer at a specified physical address
*
* This does not update any statistics. It's used to send initial HELLOs
* for NAT traversal and path verification.
*
* @param RR Runtime environment
* @param atAddress Destination address
* @param linkDesperation Link desperation
* @param now Current time
*/
void attemptToContactAt(const RuntimeEnvironment *RR,const InetAddress &atAddress,unsigned int linkDesperation,uint64_t now);
/**
* @return All known direct paths to this peer
*/

42
node/Switch.cpp
View File

@ -265,20 +265,6 @@ void Switch::send(const Packet &packet,bool encrypt)
}
}
#if 0
void Switch::sendHELLO(const Address &dest)
{
Packet outp(dest,RR->identity.address(),Packet::VERB_HELLO);
outp.append((unsigned char)ZT_PROTO_VERSION);
outp.append((unsigned char)ZEROTIER_ONE_VERSION_MAJOR);
outp.append((unsigned char)ZEROTIER_ONE_VERSION_MINOR);
outp.append((uint16_t)ZEROTIER_ONE_VERSION_REVISION);
outp.append(Utils::now());
RR->identity.serialize(outp,false);
send(outp,false);
}
#endif
bool Switch::unite(const Address &p1,const Address &p2,bool force)
{
if ((p1 == RR->identity.address())||(p2 == RR->identity.address()))
@ -370,19 +356,10 @@ bool Switch::unite(const Address &p1,const Address &p2,bool force)
void Switch::contact(const SharedPtr<Peer> &peer,const InetAddress &atAddr,unsigned int maxDesperation)
{
TRACE("sending NAT-t message to %s(%s)",peer->address().toString().c_str(),atAddr.toString().c_str());
const uint64_t now = RR->node->now();
uint64_t now = RR->node->now();
Packet outp(peer->address(),RR->identity.address(),Packet::VERB_NOP);
outp.armor(peer->key(),false);
/* Note that we don't log this as a "sent" packet or send it via the peer's
* normal send() path. That's because this is a trial packet to an
* unconfirmed address.
*
* First attempt is always at desperation zero. Then we escalate to max
* before escalating through other NAT-t strategies. */
RR->node->putPacket(atAddr,outp.data(),outp.size(),0);
// Attempt to contact at zero desperation first
peer->attemptToContactAt(RR,atAddr,0,now);
// If we have not punched through after this timeout, open refreshing can of whupass
{
@ -454,14 +431,13 @@ unsigned long Switch::doTimerTasks()
} else {
// Nope, nothing yet. Time to kill some kittens.
Packet outp(qi->peer->address(),RR->identity.address(),Packet::VERB_NOP);
outp.armor(qi->peer->key(),false);
switch(qi->strategyIteration++) {
case 0: {
// First strategy: rifle method: direct packet to known port
RR->node->putPacket(qi->inaddr,outp.data(),outp.size(),qi->currentDesperation);
qi->peer->attemptToContactAt(RR,qi->inaddr,qi->currentDesperation,now);
} break;
case 1: {
// Second strategy: shotgun method up: try a few ports above
InetAddress tmpaddr(qi->inaddr);
@ -469,9 +445,10 @@ unsigned long Switch::doTimerTasks()
for(int i=0;i<9;++i) {
if (++p > 0xffff) break;
tmpaddr.setPort((unsigned int)p);
RR->node->putPacket(tmpaddr,outp.data(),outp.size(),qi->currentDesperation);
qi->peer->attemptToContactAt(RR,tmpaddr,qi->currentDesperation,now);
}
} break;
case 2: {
// Third strategy: shotgun method down: try a few ports below
InetAddress tmpaddr(qi->inaddr);
@ -479,7 +456,7 @@ unsigned long Switch::doTimerTasks()
for(int i=0;i<3;++i) {
if (--p < 1024) break;
tmpaddr.setPort((unsigned int)p);
RR->node->putPacket(tmpaddr,outp.data(),outp.size(),qi->currentDesperation);
qi->peer->attemptToContactAt(RR,tmpaddr,qi->currentDesperation,now);
}
// Escalate link desperation after all strategies attempted
@ -493,6 +470,7 @@ unsigned long Switch::doTimerTasks()
qi->strategyIteration = 0;
}
} break;
}
qi->fireAtTime = now + ZT_NAT_T_TACTICAL_ESCALATION_DELAY;