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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
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@ -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 {