aboutsummaryrefslogtreecommitdiff
path: root/src
diff options
context:
space:
mode:
authorPieter Wuille <pieter.wuille@gmail.com>2015-03-19 09:51:59 -0700
committerPieter Wuille <pieter.wuille@gmail.com>2015-03-23 17:24:18 -0700
commitc6a63ceeb4956933588995bcf01dc3095aaeb1fc (patch)
treeb88a7fe5aebb9118f552d4be074a6e7eca22fa8d /src
parentf68ba3f67bd500a64fb8932c6b41924ddc31d76f (diff)
Always use a 50% chance to choose between tried and new entries
This change was suggested as Countermeasure 2 in Eclipse Attacks on Bitcoin’s Peer-to-Peer Network, Ethan Heilman, Alison Kendler, Aviv Zohar, Sharon Goldberg. ePrint Archive Report 2015/263. March 2015.
Diffstat (limited to 'src')
-rw-r--r--src/addrman.cpp7
-rw-r--r--src/addrman.h6
-rw-r--r--src/net.cpp3
3 files changed, 7 insertions, 9 deletions
diff --git a/src/addrman.cpp b/src/addrman.cpp
index eb431ec59c..5d9527f0e1 100644
--- a/src/addrman.cpp
+++ b/src/addrman.cpp
@@ -332,14 +332,13 @@ void CAddrMan::Attempt_(const CService& addr, int64_t nTime)
info.nAttempts++;
}
-CAddress CAddrMan::Select_(int nUnkBias)
+CAddress CAddrMan::Select_()
{
if (size() == 0)
return CAddress();
- double nCorTried = sqrt(nTried) * (100.0 - nUnkBias);
- double nCorNew = sqrt(nNew) * nUnkBias;
- if ((nCorTried + nCorNew) * GetRandInt(1 << 30) / (1 << 30) < nCorTried) {
+ // Use a 50% chance for choosing between tried and new table entries.
+ if (nTried > 0 && (nNew == 0 || GetRandInt(2) == 0)) {
// use a tried node
double fChanceFactor = 1.0;
while (1) {
diff --git a/src/addrman.h b/src/addrman.h
index f7c6318448..fe06a745b5 100644
--- a/src/addrman.h
+++ b/src/addrman.h
@@ -231,7 +231,7 @@ protected:
//! Select an address to connect to.
//! nUnkBias determines how much to favor new addresses over tried ones (min=0, max=100)
- CAddress Select_(int nUnkBias);
+ CAddress Select_();
#ifdef DEBUG_ADDRMAN
//! Perform consistency check. Returns an error code or zero.
@@ -533,13 +533,13 @@ public:
* Choose an address to connect to.
* nUnkBias determines how much "new" entries are favored over "tried" ones (0-100).
*/
- CAddress Select(int nUnkBias = 50)
+ CAddress Select()
{
CAddress addrRet;
{
LOCK(cs);
Check();
- addrRet = Select_(nUnkBias);
+ addrRet = Select_();
Check();
}
return addrRet;
diff --git a/src/net.cpp b/src/net.cpp
index 0723ee218a..d8991ffa8d 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -1221,8 +1221,7 @@ void ThreadOpenConnections()
int nTries = 0;
while (true)
{
- // use an nUnkBias between 10 (no outgoing connections) and 90 (8 outgoing connections)
- CAddress addr = addrman.Select(10 + min(nOutbound,8)*10);
+ CAddress addr = addrman.Select();
// if we selected an invalid address, restart
if (!addr.IsValid() || setConnected.count(addr.GetGroup()) || IsLocal(addr))