From 03c117b009da0c6eb1db62d47b9a3f1185bed2a2 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Wed, 20 Jan 2016 12:04:38 -0800
Subject: [PATCH] more DOS protection.

---
 lib/bcoin/pool.js | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/lib/bcoin/pool.js b/lib/bcoin/pool.js
index 9720d4c2..5b3e18b8 100644
--- a/lib/bcoin/pool.js
+++ b/lib/bcoin/pool.js
@@ -490,8 +490,16 @@ Pool.prototype._handleBlocks = function _handleBlocks(hashes, peer) {
   for (i = 0; i < hashes.length; i++) {
     hash = hashes[i];
 
-    // Resolve orphan chain
     if (this.chain.hasOrphan(hash)) {
+      // Make sure the peer doesn't send us
+      // more than 200 orphans every 3 minutes.
+      if (this.orphaning(peer)) {
+        this.emit('debug', 'Peer is orphaning (%s)', peer.host);
+        this.misbehaving(peer, 100);
+        return;
+      }
+
+      // Resolve orphan chain.
       peer.loadBlocks(
         this.chain.locatorHashes(),
         this.chain.getOrphanRoot(hash)
@@ -542,7 +550,7 @@ Pool.prototype._handleInv = function _handleInv(hashes, peer) {
 
 Pool.prototype._handleBlock = function _handleBlock(block, peer) {
   var self = this;
-  var requested, hasPrev;
+  var requested;
 
   // Fulfill our request.
   requested = this._response(block);
@@ -566,7 +574,9 @@ Pool.prototype._handleBlock = function _handleBlock(block, peer) {
   // Ensure this is not a continuation
   // of an invalid chain.
   if (this.block.invalid[block.prevBlock]) {
-    this.emit('debug', 'Peer is sending an invalid chain (%s)', peer.host);
+    this.emit('debug',
+      'Peer is sending an invalid continuation chain (%s)',
+      peer.host);
     this.misbehaving(peer, 100);
     return false;
   }
@@ -604,7 +614,7 @@ Pool.prototype._handleBlock = function _handleBlock(block, peer) {
         return false;
 
       // Make sure the peer doesn't send us
-      // more than 100 orphans every 3 minutes.
+      // more than 200 orphans every 3 minutes.
       if (this.orphaning(peer)) {
         this.emit('debug', 'Peer is orphaning (%s)', peer.host);
         this.misbehaving(peer, 100);
@@ -618,6 +628,7 @@ Pool.prototype._handleBlock = function _handleBlock(block, peer) {
       if (this._addIndex(block, peer))
         this.emit('pool block', block, peer);
 
+      // Resolve orphan chain.
       this.peers.load.loadBlocks(
         this.chain.locatorHashes(),
         this.chain.getOrphanRoot(block)
@@ -629,6 +640,11 @@ Pool.prototype._handleBlock = function _handleBlock(block, peer) {
     }
   } else {
     if (!this.chain.hasBlock(block.prevBlock)) {
+      // Special case for genesis block.
+      if (block.isGenesis())
+        return false;
+
+      // Increase banscore by 10 if we're using getheaders.
       if (!this.options.multiplePeers) {
         if (this.misbehaving(peer, 10))
           return false;
@@ -1688,7 +1704,7 @@ Pool.prototype.orphaning = function orphaning(peer) {
 
   peer._orphans += 1;
 
-  if (peer._orphans > 100)
+  if (peer._orphans > 200)
     return true;
 
   return false;