From e1ec89fe7dce99b59eb40deb7f763aaae788d02d Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Wed, 6 Jan 2016 01:36:38 -0800
Subject: [PATCH] sigops

---
 lib/bcoin/block.js              | 27 ++++++++++--------
 lib/bcoin/protocol/constants.js |  6 +++-
 lib/bcoin/script.js             | 49 +++++++++++++++++++++++++++++++++
 lib/bcoin/tx.js                 | 20 +++++++++++---
 4 files changed, 85 insertions(+), 17 deletions(-)

diff --git a/lib/bcoin/block.js b/lib/bcoin/block.js
index 684c39b1..f086ca47 100644
--- a/lib/bcoin/block.js
+++ b/lib/bcoin/block.js
@@ -68,15 +68,6 @@ function Block(data, subtype) {
       tx.ts = tx.ts || self.ts;
       return tx;
     });
-
-    // if (this.version >= 2 && this.height === -1) {
-    //   tx = this.txs[0];
-    //   if (tx && tx.isCoinbase()) {
-    //     height = bcoin.script.coinbaseHeight(tx.inputs[0].script, this);
-    //     if (height > 0)
-    //       this.height = height;
-    //   }
-    // }
   }
 
   this.verify();
@@ -280,7 +271,10 @@ Block.prototype._verify = function _verify() {
 };
 
 Block.prototype.postVerify = function postVerify() {
-  var prev, i, tx, cb;
+  var prev, i, tx, cb, sigops;
+  var flags = {};
+  var bip16time = 1333238400;
+  var strictp2sh = this.ts >= bip16time;
 
   if (this.subtype !== 'block')
     return true;
@@ -332,11 +326,20 @@ Block.prototype.postVerify = function postVerify() {
 
   // sig validation (bip66)
   if (this.version >= 3 && prev.needsUpgrade(3))
-    this.scriptFlags |= 1; // dersig
+    flags.strictder = true;
 
   // checklocktimeverify (bip65)
   if (this.version >= 4 && prev.needsUpgrade(4))
-    this.scriptFlags |= 2;
+    flags.cltv = true;
+
+  sigops = 0;
+  for (i = 0; i < this.txs.length; i++) {
+    if (tx.sigops(true) > constants.script.maxTxSigops)
+      return false;
+    sigops += tx.sigops(strictp2sh);
+    if (sigops > constants.script.maxBlockSigops)
+      return false;
+  }
 
   return true;
 };
diff --git a/lib/bcoin/protocol/constants.js b/lib/bcoin/protocol/constants.js
index 2717d4ca..f74594ce 100644
--- a/lib/bcoin/protocol/constants.js
+++ b/lib/bcoin/protocol/constants.js
@@ -163,7 +163,11 @@ exports.script = {
   maxSize: 10000,
   maxStack: 1000,
   maxPush: 520,
-  maxOps: 201
+  maxOps: 201,
+  maxPubkeysPerMultisig: 20,
+  maxBlockSigops: exports.block.maxSize / 50,
+  maxScripthashSigops: 15,
+  maxTxSigops: exports.block.maxSize / 50 / 5
 };
 
 exports.reject = {
diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index 4fd5c496..dd95cb2e 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -1404,3 +1404,52 @@ script.format = function format(input, output) {
 
   return scripts;
 };
+
+script.pushOnly = function pushOnly(s) {
+  var i, op;
+  for (i = 0; i < s.length; i++) {
+    op = s[i];
+    if (Array.isArray(op) || (op >= 1 && op <= 16))
+      continue;
+    return false;
+  }
+  return true;
+};
+
+script.sigops = function sigops(s, accurate) {
+  var i, op;
+  var n = 0;
+  var lastOp = -1;
+
+  for (i = 0; i < s.length; i++) {
+    op = s[i];
+    if (Array.isArray(op))
+      continue;
+    if (op === 'checksig' || op === 'checksigverify') {
+      n++;
+    } else if (op === 'checkmultisig' || op === 'checkmultisigverify') {
+      if (accurate && lastOp >= 1 && lastOp <= 16) {
+        n += lastOp;
+      } else {
+        n += constants.script.maxPubkeysPerMultisig;
+      }
+    }
+    lastOp = op;
+    if (lastOp === null)
+      return 0;
+  }
+
+  return n;
+};
+
+script.sigopsScripthash = function sigopsScripthash(s, accurate) {
+  if (!script.isScripthashInput(s))
+    return 0;
+
+  if (!script.pushOnly(input))
+    return 0;
+
+  s = script.decode(input[input.length - 1]);
+
+  return script.sigops(s, accurate);
+};
diff --git a/lib/bcoin/tx.js b/lib/bcoin/tx.js
index a6c658f5..d42666f5 100644
--- a/lib/bcoin/tx.js
+++ b/lib/bcoin/tx.js
@@ -537,10 +537,9 @@ TX.prototype.verify = function verify(index, force) {
     prev = input.out.tx.outputs[input.out.index].script;
 
     if (bcoin.script.isScripthash(prev)) {
-      // p2sh transactions cannot have anything
-      // other than pushdata ops in the scriptSig
-      push = input.script.slice(1).every(Array.isArray);
-      if (!push)
+      // P2SH transactions cannot have anything
+      // other than pushdata ops in the scriptSig.
+      if (!bcoin.script.pushOnly(input.script))
         return false;
     }
 
@@ -882,6 +881,19 @@ TX.prototype._isFinal = function _isFinal(height, ts) {
   return true;
 };
 
+TX.prototype.sigops = function sigops(scripthash) {
+  var n = 0;
+  this.inputs.forEach(function(input) {
+    n += bcoin.script.sigops(input.script);
+    if (scripthash)
+      n += bcoin.script.sigopsScripthash(input.script);
+  });
+  this.outputs.forEach(function(output) {
+    n += bcoin.script.sigops(output.script);
+  });
+  return n;
+};
+
 TX.prototype.getHeight = function getHeight() {
   if (!this.chain)
     return -1;