/*       +------------------------------------+
 *       | Inspire Internet Relay Chat Daemon |
 *       +------------------------------------+
 *
 *  InspIRCd: (C) 2002-2007 InspIRCd Development Team
 * See: http://www.inspircd.org/wiki/index.php/Credits
 *
 * This program is free but copyrighted software; see
 *            the file COPYING for details.
 *
 * ---------------------------------------------------
 */

#include "inspircd.h"
#include "users.h"
#include "channels.h"
#include "modules.h"

/* $ModDesc: Provides support for RFC 1413 ident lookups */

// Version 1.5.0.0 - Updated to use InspSocket, faster and neater.

/** Handles RFC1413 ident connections to users
 */
class RFC1413 : public InspSocket
{
 protected:
	socklen_t uslen;	 // length of our port number
	socklen_t themlen;	 // length of their port number
	char ident_request[128]; // buffer used to make up the request string
 public:

	userrec* u;		 // user record that the lookup is associated with
	int ufd;

	RFC1413(InspIRCd* SI, userrec* user, int maxtime, const std::string &bindto) : InspSocket(SI, user->GetIPString(), 113, false, maxtime, bindto), u(user)
	{
		ufd = user->GetFd();
	}

	virtual void OnTimeout()
	{
		// When we timeout, the connection failed within the allowed timeframe,
		// so we just display a notice, and tidy off the ident_data.
		if (u && (Instance->SE->GetRef(ufd) == u))
		{
			u->Shrink("ident_data");
			Instance->next_call = Instance->Time();
		}
	}

	virtual bool OnDataReady()
	{
		char* ibuf = this->Read();
		if (ibuf)
		{
			char* savept;
			char* section = strtok_r(ibuf,":",&savept);
			while (section)
			{
				if (strstr(section,"USERID"))
				{
					section = strtok_r(NULL,":",&savept);
					if (section)
					{
						// ID type, usually UNIX or OTHER... we dont want it, so read the next token
						section = strtok_r(NULL,":",&savept);
						if (section)
						{
							while (*section == ' ') section++; // strip leading spaces
							for (char* j = section; *j; j++)
							if ((*j < 33) || (*j > 126))
								*j = '\0'; // truncate at invalid chars
							if (*section)
							{
								if (u && (Instance->SE->GetRef(ufd) == u))
								{
									if (this->Instance->IsIdent(section))
									{
										u->Extend("IDENT", new std::string(std::string(section) + "," + std::string(u->ident)));
										strlcpy(u->ident,section,IDENTMAX);
										u->WriteServ("NOTICE "+std::string(u->nick)+" :*** Found your ident: "+std::string(u->ident));
									}
								}
							}
							return false;
						}
					}
				}
				section = strtok_r(NULL,":",&savept);
			}
		}
		return false;
	}

	virtual void OnClose()
	{
		// tidy up after ourselves when the connection is done.
		// We receive this event straight after a timeout, too.
		//
		//
		// OK, now listen up. The weird looking check here is
		// REQUIRED. Don't try and optimize it away.
		//
		// When a socket is closed, it is not immediately removed
		// from the socket list, there can be a short delay
		// before it is culled from the list. This means that
		// without this check, there is a chance that a user
		// may not exist when we come to ::Shrink them, which
		// results in a segfault. The value of "u" may not
		// always be NULL at this point, so, what we do is
		// check against the fd_ref_table, to see if (1) the user
		// exists, and (2) its the SAME user, on the same file
		// descriptor that they were when the lookup began.
		//
		// Fixes issue reported by webs, 7 Jun 2006
		if (u && (Instance->SE->GetRef(ufd) == u))
		{
			Instance->next_call = Instance->Time();
			u->Shrink("ident_data");
		}
	}

	virtual void OnError(InspSocketError e)
	{
		if (u && (Instance->SE->GetRef(ufd) == u))
		{
			if (*u->ident == '~')
				u->WriteServ("NOTICE "+std::string(u->nick)+" :*** Could not find your ident, using "+std::string(u->ident)+" instead.");

			Instance->next_call = Instance->Time();
			u->Shrink("ident_data");
		}
	}

	virtual bool OnConnected()
	{
		if (u && (Instance->SE->GetRef(ufd) == u))
		{
			sockaddr* sock_us = new sockaddr[2];
			sockaddr* sock_them = new sockaddr[2];
			bool success = false;
			uslen = sizeof(sockaddr_in);
			themlen = sizeof(sockaddr_in);
#ifdef IPV6
			if (this->u->GetProtocolFamily() == AF_INET6)
			{
				themlen = sizeof(sockaddr_in6);
				uslen = sizeof(sockaddr_in6);
			}
#endif
			success = ((getsockname(this->u->GetFd(),sock_us,&uslen) || getpeername(this->u->GetFd(), sock_them, &themlen)));
			if (success)
			{
				delete[] sock_us;
				delete[] sock_them;
				return false;
			}
			else
			{
				// send the request in the following format: theirsocket,oursocket
#ifdef IPV6
				if (this->u->GetProtocolFamily() == AF_INET6)
					snprintf(ident_request,127,"%d,%d\r\n",ntohs(((sockaddr_in6*)sock_them)->sin6_port),ntohs(((sockaddr_in6*)sock_us)->sin6_port));
				else
#endif
				snprintf(ident_request,127,"%d,%d\r\n",ntohs(((sockaddr_in*)sock_them)->sin_port),ntohs(((sockaddr_in*)sock_us)->sin_port));
				this->Write(ident_request);
				delete[] sock_us;
				delete[] sock_them;
				return true;
			}
		}
		else
		{
			Instance->next_call = Instance->Time();
			return true;
		}
	}
};

class ModuleIdent : public Module
{

	ConfigReader* Conf;
	int IdentTimeout;
	std::string PortBind;

 public:
	void ReadSettings()
	{
		Conf = new ConfigReader(ServerInstance);
		IdentTimeout = Conf->ReadInteger("ident", "timeout", 0, true);
		PortBind = Conf->ReadValue("ident", "bind", 0);
		if (!IdentTimeout)
			IdentTimeout = 1;
		DELETE(Conf);
	}

	ModuleIdent(InspIRCd* Me)
		: Module(Me)
	{

		ReadSettings();
	}

	void Implements(char* List)
	{
		List[I_OnCleanup] = List[I_OnRehash] = List[I_OnUserRegister] = List[I_OnCheckReady] = List[I_OnUserDisconnect] = 1;
	}

	void OnSyncUserMetaData(userrec* user, Module* proto,void* opaque, const std::string &extname, bool displayable)
	{
		if ((displayable) && (extname == "IDENT"))
		{
			std::string* ident;
			if (GetExt("IDENT", ident))
				proto->ProtoSendMetaData(opaque, TYPE_USER, user, extname, *ident);
		}
	}


	virtual void OnRehash(userrec* user, const std::string &parameter)
	{
		ReadSettings();
	}

	virtual int OnUserRegister(userrec* user)
	{
		/*
		 * when the new user connects, before they authenticate with USER/NICK/PASS, we do
		 * their ident lookup. We do this by instantiating an object of type RFC1413, which
		 * is derived from InspSocket, and inserting it into the socket engine using the
		 * Server::AddSocket() call.
		 */
		char newident[MAXBUF];
		strcpy(newident,"~");
		strlcat(newident,user->ident,IDENTMAX);
		strlcpy(user->ident,newident,IDENTMAX);
		

		user->WriteServ("NOTICE "+std::string(user->nick)+" :*** Looking up your ident...");
		RFC1413* ident = new RFC1413(ServerInstance, user, IdentTimeout, PortBind);
		if ((ident->GetState() == I_CONNECTING) || (ident->GetState() == I_CONNECTED))
		{
			user->Extend("ident_data", (char*)ident);
		}
		else
		{
			user->WriteServ("NOTICE "+std::string(user->nick)+" :*** Could not find your ident, using "+std::string(user->ident)+" instead.");
			ServerInstance->next_call = ServerInstance->Time();
		}
		return 0;
	}

	virtual bool OnCheckReady(userrec* user)
	{
		/*
		 * The socket engine will clean up their ident request for us when it completes,
		 * either due to timeout or due to closing, so, we just hold them until they dont
		 * have an ident field any more.
		 */
		RFC1413* ident;
		return (!user->GetExt("ident_data", ident));
	}

	virtual void OnCleanup(int target_type, void* item)
	{
		if (target_type == TYPE_USER)
		{
			userrec* user = (userrec*)item;
			RFC1413* ident;
			std::string* identstr;
			if (user->GetExt("ident_data", ident))
			{
				// FIX: If the user record is deleted, the socket wont be removed
				// immediately so there is chance of the socket trying to write to
				// a user which has now vanished! To prevent this, set ident::u
				// to NULL and check it so that we dont write users who have gone away.
				ident->u = NULL;
				ServerInstance->SE->DelFd(ident);
				//delete ident;
			}
			if (user->GetExt("IDENT", identstr))
			{
				delete identstr;
			}
		}
	}

	virtual void OnUserDisconnect(userrec* user)
	{
		/*
		 * when the user quits tidy up any ident lookup they have pending to keep things tidy.
		 * When we call RemoveSocket, the abstractions tied into the system evnetually work their
		 * way to RFC1459::OnClose(), which shrinks off the ident_data for us, so we dont need
		 * to do it here. If we don't tidy this up, there may still be lingering idents for users
		 * who have quit, as class RFC1459 is only loosely bound to userrec* via a pair of pointers
		 * and this would leave at least one of the invalid ;)
		 */
		RFC1413* ident;
		std::string* identstr;
		if (user->GetExt("ident_data", ident))
		{
			ident->u = NULL;
			ServerInstance->SE->DelFd(ident);
		}
		if (user->GetExt("IDENT", identstr))
		{
			delete identstr;
		}
	}

	virtual ~ModuleIdent()
	{
		ServerInstance->next_call = ServerInstance->Time();
	}

	virtual Version GetVersion()
	{
		return Version(1,1,0,0,VF_VENDOR,API_VERSION);
	}

};

MODULE_INIT(ModuleIdent)