Send a MODE request when JOINing

This kind of reverts/fixes f1cb09bd9c.

Robby found a bug with evil ChanServ which goes like this:

- You join an empty, but registered channel and the IRCd applies its default
  modes (+nt), but ZNC didn't ask for MODE, so doesn't know this.
- ChanServ applies whatever channel modes it wants to apply. This causes ZNC to
  see a mode change (e.g. +s).

The result of this is that ZNC thinks that the channel has mode +s and it will
tell every client that connects to it about this.

The fix is to send a MODE request when JOINing. To make sure that we don't
confuse clients, we block the reply.

Signed-off-by: Uli Schlachter <psychon@znc.in>

Chan.cpp

@@ -54,6 +54,7 @@ CChan::~CChan() {
 
 void CChan::Reset() {
 	m_bIsOn = false;
+	m_bModeKnown = false;
 	m_musModes.clear();
 	m_sTopic = "";
 	m_sTopicOwner = "";

Chan.h

@@ -100,6 +100,7 @@ public:
 	// !wrappers
 
 	// Setters
+	void SetModeKnown(bool b) { m_bModeKnown = b; }
 	void SetIsOn(bool b) { m_bIsOn = b; if (!b) { Reset(); } }
 	void SetKey(const CString& s) { m_sKey = s; }
 	void SetTopic(const CString& s) { m_sTopic = s; }
@@ -118,6 +119,7 @@ public:
 	// !Setters
 
 	// Getters
+	bool IsModeKnown() const { return m_bModeKnown; }
 	bool HasMode(unsigned char uMode) const;
 	CString GetOptions() const;
 	CString GetModeArg(unsigned char uMode) const;
@@ -162,6 +164,7 @@ protected:
 	unsigned int                 m_uBufferCount;
 	vector<CString>              m_vsBuffer;
 
+	bool                         m_bModeKnown;
 	map<unsigned char, CString>  m_musModes;
 };
 

IRCSock.cpp

@@ -196,6 +196,15 @@ void CIRCSock::ReadLine(const CString& sData) {
 
 				if (pChan) {
 					pChan->SetModes(sRest.Token(1, true));
+
+					// We don't SetModeKnown(true) here,
+					// because a 329 will follow
+					if (!pChan->IsModeKnown()) {
+						// When we JOIN, we send a MODE
+						// request. This makes sure the
+						// reply isn't forwarded.
+						return;
+					}
 				}
 			}
 				break;
@@ -206,6 +215,14 @@ void CIRCSock::ReadLine(const CString& sData) {
 				if (pChan) {
 					unsigned long ulDate = sLine.Token(4).ToULong();
 					pChan->SetCreationDate(ulDate);
+
+					if (!pChan->IsModeKnown()) {
+						pChan->SetModeKnown(true);
+						// When we JOIN, we send a MODE
+						// request. This makes sure the
+						// reply isn't forwarded.
+						return;
+					}
 				}
 			}
 				break;
@@ -455,6 +472,7 @@ void CIRCSock::ReadLine(const CString& sData) {
 					pChan->ResetJoinTries();
 					pChan->Enable();
 					pChan->SetIsOn(true);
+					PutIRC("MODE " + sChan);
 				}
 			} else {
 				pChan = m_pUser->FindChan(sChan);