-fuzzmessagestest=N : randomly corrupt 1-of-N sent messages

I needed this to test the new "reject" p2p message, but it should be generally
useful for fuzz-testing network message handling code.
This commit is contained in:
Gavin Andresen 2013-10-28 16:28:00 +10:00
parent d5d1425657
commit 9038b18f46
2 changed files with 44 additions and 1 deletions

View file

@ -1894,3 +1894,38 @@ uint64 CNode::GetTotalBytesSent()
LOCK(cs_totalBytesSent);
return nTotalBytesSent;
}
void CNode::Fuzz(int nChance)
{
if (!fSuccessfullyConnected) return; // Don't fuzz initial handshake
if (GetRand(nChance) != 0) return; // Fuzz 1 of every nChance messages
switch (GetRand(3))
{
case 0:
// xor a random byte with a random value:
if (!ssSend.empty()) {
CDataStream::size_type pos = GetRand(ssSend.size());
ssSend[pos] ^= (unsigned char)(GetRand(256));
}
break;
case 1:
// delete a random byte:
if (!ssSend.empty()) {
CDataStream::size_type pos = GetRand(ssSend.size());
ssSend.erase(ssSend.begin()+pos);
}
break;
case 2:
// insert a random byte at a random position
{
CDataStream::size_type pos = GetRand(ssSend.size());
char ch = (char)GetRand(256);
ssSend.insert(ssSend.begin()+pos, ch);
}
break;
}
// Chance of more than one change half the time:
// (more changes exponentially less likely):
Fuzz(2);
}

View file

@ -218,6 +218,9 @@ protected:
static CCriticalSection cs_setBanned;
int nMisbehavior;
// Basic fuzz-testing
void Fuzz(int nChance); // modifies ssSend
public:
uint256 hashContinue;
CBlockIndex* pindexLastGetBlocksBegin;
@ -434,12 +437,17 @@ public:
// TODO: Document the precondition of this function. Is cs_vSend locked?
void EndMessage() UNLOCK_FUNCTION(cs_vSend)
{
if (mapArgs.count("-dropmessagestest") && GetRand(atoi(mapArgs["-dropmessagestest"])) == 0)
// The -*messagestest options are intentionally not documented in the help message,
// since they are only used during development to debug the networking code and are
// not intended for end-users.
if (mapArgs.count("-dropmessagestest") && GetRand(GetArg("-dropmessagestest", 2)) == 0)
{
LogPrint("net", "dropmessages DROPPING SEND MESSAGE\n");
AbortMessage();
return;
}
if (mapArgs.count("-fuzzmessagestest"))
Fuzz(GetArg("-fuzzmessagestest", 10));
if (ssSend.size() == 0)
return;