/*
 * WebIRC / CGI:IRC Support
 * (C) Copyright 2006-.. Bram Matthys (Syzop) and the UnrealIRCd team
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 1, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include "unrealircd.h"

/* Types */
typedef struct ConfigItem_webirc ConfigItem_webirc;

typedef enum {
	WEBIRC_PASS=1, WEBIRC_WEBIRC=2
} WEBIRCType;

struct ConfigItem_webirc {
	ConfigItem_webirc *prev, *next;
	ConfigFlag flag;
	ConfigItem_mask *mask;
	WEBIRCType type;
	AuthConfig *auth;
};

/* Module header */
ModuleHeader MOD_HEADER
= {
	"webirc",
	"5.0",
	"WebIRC/CGI:IRC Support",
	"UnrealIRCd Team",
	"unrealircd-6",
};

/* Global variables */
ModDataInfo *webirc_md = NULL;
ConfigItem_webirc *conf_webirc = NULL;

/* Forward declarations */
CMD_FUNC(cmd_webirc);
int webirc_local_pass(Client *client, const char *password);
int webirc_config_test(ConfigFile *, ConfigEntry *, int, int *);
int webirc_config_run(ConfigFile *, ConfigEntry *, int);
void webirc_free_conf(void);
void delete_webircblock(ConfigItem_webirc *e);
const char *webirc_md_serialize(ModData *m);
void webirc_md_unserialize(const char *str, ModData *m);
void webirc_md_free(ModData *md);
int webirc_secure_connect(Client *client);

#define IsWEBIRC(x)			(moddata_client(x, webirc_md).l)
#define IsWEBIRCSecure(x)	(moddata_client(x, webirc_md).l == 2)
#define ClearWEBIRC(x)		do { moddata_client(x, webirc_md).l = 0; } while(0)
#define SetWEBIRC(x)		do { moddata_client(x, webirc_md).l = 1; } while(0)
#define SetWEBIRCSecure(x)	do { moddata_client(x, webirc_md).l = 2; } while(0)

#define MSG_WEBIRC "WEBIRC"

MOD_TEST()
{
	HookAdd(modinfo->handle, HOOKTYPE_CONFIGTEST, 0, webirc_config_test);
	return MOD_SUCCESS;
}

/** Called upon module init */
MOD_INIT()
{
	ModDataInfo mreq;

	MARK_AS_OFFICIAL_MODULE(modinfo);
	
	memset(&mreq, 0, sizeof(mreq));
	mreq.name = "webirc";
	mreq.type = MODDATATYPE_CLIENT;
	mreq.serialize = webirc_md_serialize;
	mreq.unserialize = webirc_md_unserialize;
	mreq.free = webirc_md_free;
	mreq.sync = MODDATA_SYNC_EARLY;
	webirc_md = ModDataAdd(modinfo->handle, mreq);
	if (!webirc_md)
	{
		config_error("could not register webirc moddata");
		return MOD_FAILED;
	}

	HookAdd(modinfo->handle, HOOKTYPE_CONFIGRUN, 0, webirc_config_run);
	HookAdd(modinfo->handle, HOOKTYPE_LOCAL_PASS, 0, webirc_local_pass);
	HookAdd(modinfo->handle, HOOKTYPE_SECURE_CONNECT, 0, webirc_secure_connect);

	CommandAdd(modinfo->handle, MSG_WEBIRC, cmd_webirc, MAXPARA, CMD_UNREGISTERED);
		
	return MOD_SUCCESS;
}

/** Called upon module load */
MOD_LOAD()
{
	return MOD_SUCCESS;
}

/** Called upon unload */
MOD_UNLOAD()
{
	webirc_free_conf();
	return MOD_SUCCESS;
}

void webirc_free_conf(void)
{
	ConfigItem_webirc *webirc_ptr, *next;

	for (webirc_ptr = conf_webirc; webirc_ptr; webirc_ptr = next)
	{
		next = webirc_ptr->next;
		delete_webircblock(webirc_ptr);
	}
	conf_webirc = NULL;
}

void delete_webircblock(ConfigItem_webirc *e)
{
	unreal_delete_masks(e->mask);
	if (e->auth)
		Auth_FreeAuthConfig(e->auth);
	DelListItem(e, conf_webirc);
	safe_free(e);
}

int webirc_config_test(ConfigFile *cf, ConfigEntry *ce, int type, int *errs)
{
	ConfigEntry *cep;
	int errors = 0;
	char has_mask = 0; /* mandatory */
	char has_password = 0; /* mandatory */
	char has_type = 0; /* optional (used for dup checking) */
	WEBIRCType webirc_type = WEBIRC_WEBIRC; /* the default */

	if (type != CONFIG_MAIN)
		return 0;
	
	if (!ce)
		return 0;
	
	if (!strcmp(ce->name, "cgiirc"))
	{
		config_error("%s:%i: the cgiirc block has been renamed to webirc and "
		             "the syntax has changed in UnrealIRCd 4",
		             ce->file->filename, ce->line_number);
		*errs = 1;
		return -1;
	}

	if (strcmp(ce->name, "webirc"))
		return 0; /* not interested in non-webirc stuff.. */

	/* Now actually go parse the webirc { } block */
	for (cep = ce->items; cep; cep = cep->next)
	{
		if (!cep->value)
		{
			config_error_empty(cep->file->filename, cep->line_number,
				"webirc", cep->name);
			errors++;
			continue;
		}
		if (!strcmp(cep->name, "mask"))
		{
			if (cep->value || cep->items)
				has_mask = 1;
		}
		else if (!strcmp(cep->name, "password"))
		{
			if (has_password)
			{
				config_warn_duplicate(cep->file->filename, 
					cep->line_number, "webirc::password");
				continue;
			}
			has_password = 1;
			if (Auth_CheckError(cep) < 0)
				errors++;
		}
		else if (!strcmp(cep->name, "type"))
		{
			if (has_type)
			{
				config_warn_duplicate(cep->file->filename,
					cep->line_number, "webirc::type");
			}
			has_type = 1;
			if (!strcmp(cep->value, "webirc"))
				webirc_type = WEBIRC_WEBIRC;
			else if (!strcmp(cep->value, "old"))
				webirc_type = WEBIRC_PASS;
			else
			{
				config_error("%s:%i: unknown webirc::type '%s', should be either 'webirc' or 'old'",
					cep->file->filename, cep->line_number, cep->value);
				errors++;
			}
		}
		else
		{
			config_error_unknown(cep->file->filename, cep->line_number,
				"webirc", cep->name);
			errors++;
		}
	}
	if (!has_mask)
	{
		config_error_missing(ce->file->filename, ce->line_number,
			"webirc::mask");
		errors++;
	}

	if (!has_password && (webirc_type == WEBIRC_WEBIRC))
	{
		config_error_missing(ce->file->filename, ce->line_number,
			"webirc::password");
		errors++;
	}
	
	if (has_password && (webirc_type == WEBIRC_PASS))
	{
		config_error("%s:%i: webirc block has type set to 'old' but has a password set. "
		             "Passwords are not used with type 'old'. Either remove the password or "
		             "use the 'webirc' method instead.",
		             ce->file->filename, ce->line_number);
		errors++;
	}

	*errs = errors;
	return errors ? -1 : 1;
}

int webirc_config_run(ConfigFile *cf, ConfigEntry *ce, int type)
{
	ConfigEntry *cep;
	ConfigItem_webirc *webirc = NULL;
	
	if (type != CONFIG_MAIN)
		return 0;
	
	if (!ce || !ce->name || strcmp(ce->name, "webirc"))
		return 0; /* not interested */

	webirc = safe_alloc(sizeof(ConfigItem_webirc));
	webirc->type = WEBIRC_WEBIRC; /* default */

	for (cep = ce->items; cep; cep = cep->next)
	{
		if (!strcmp(cep->name, "mask"))
			unreal_add_masks(&webirc->mask, cep);
		else if (!strcmp(cep->name, "password"))
			webirc->auth = AuthBlockToAuthConfig(cep);
		else if (!strcmp(cep->name, "type"))
		{
			if (!strcmp(cep->value, "webirc"))
				webirc->type = WEBIRC_WEBIRC;
			else if (!strcmp(cep->value, "old"))
				webirc->type = WEBIRC_PASS;
			else
				abort();
		}
	}
	
	AddListItem(webirc, conf_webirc);
	
	return 0;
}

const char *webirc_md_serialize(ModData *m)
{
	static char buf[32];
	if (m->i == 0)
		return NULL; /* not set */
	snprintf(buf, sizeof(buf), "%d", m->i);
	return buf;
}

void webirc_md_unserialize(const char *str, ModData *m)
{
	m->i = atoi(str);
}

void webirc_md_free(ModData *md)
{
	/* we have nothing to free actually, but we must set to zero */
	md->l = 0;
}

ConfigItem_webirc *find_webirc(Client *client, const char *password, WEBIRCType type, char **errorstr)
{
	ConfigItem_webirc *e;
	char *error = NULL;

	for (e = conf_webirc; e; e = e->next)
	{
		if ((e->type == type) && unreal_mask_match(client, e->mask))
		{
			if (type == WEBIRC_WEBIRC)
			{
				/* Check password */
				if (!Auth_Check(client, e->auth, password))
					error = "CGI:IRC -- Invalid password";
				else
					return e; /* Found matching block, return straight away */
			} else {
				return e; /* The WEBIRC_PASS type has no password checking */
			}
		}
	}

	if (error)
		*errorstr = error; /* Invalid password (this error was delayed) */
	else
		*errorstr = "CGI:IRC -- No access"; /* No match found */

	return NULL;
}

#define WEBIRC_STRING     "WEBIRC_"
#define WEBIRC_STRINGLEN  (sizeof(WEBIRC_STRING)-1)

/* Does the CGI:IRC host spoofing work */
void dowebirc(Client *client, const char *ip, const char *host, const char *options)
{
	char scratch[64];

	if (IsWEBIRC(client))
	{
		exit_client(client, NULL, "Double CGI:IRC request (already identified)");
		return;
	}

	if (host && !strcmp(ip, host))
		host = NULL; /* host did not resolve, make it NULL */

	/* STEP 1: Update client->local->ip
	   inet_pton() returns 1 on success, 0 on bad input, -1 on bad AF */
	if (!is_valid_ip(ip))
	{
		/* then we have an invalid IP */
		exit_client(client, NULL, "Invalid IP address");
		return;
	}

	/* STEP 2: Update GetIP() */
	safe_strdup(client->ip, ip);
		
	/* STEP 3: Update client->local->hostp */
	/* (free old) */
	if (client->local->hostp)
	{
		unreal_free_hostent(client->local->hostp);
		client->local->hostp = NULL;
	}
	/* (create new) */
	if (host && valid_host(host, 1))
		client->local->hostp = unreal_create_hostent(host, client->ip);

	/* STEP 4: Update sockhost
	   Make sure that if this any IPv4 address is _not_ prefixed with
	   "::ffff:" by using Inet_ia2p().
	 */
	// Hmm I ignored above warning. May be bad during transition period.
	strlcpy(client->local->sockhost, client->ip, sizeof(client->local->sockhost));

	SetWEBIRC(client);

	if (options)
	{
		char optionsbuf[BUFSIZE];
		char *name, *p = NULL, *p2;
		strlcpy(optionsbuf, options, sizeof(optionsbuf));
		for (name = strtoken(&p, optionsbuf, " "); name; name = strtoken(&p, NULL, " "))
		{
			p2 = strchr(name, '=');
			if (p2)
				*p2 = '\0';
			if (!strcmp(name, "secure") && IsSecure(client))
			{
				/* The entire [client]--[webirc gw]--[server] chain is secure */
				SetWEBIRCSecure(client);
			}
		}
	}

	/* blacklist_start_check() */
	if (RCallbacks[CALLBACKTYPE_BLACKLIST_CHECK] != NULL)
		RCallbacks[CALLBACKTYPE_BLACKLIST_CHECK]->func.intfunc(client);

	/* Check (g)zlines right now; these are normally checked upon accept(),
	 * but since we know the IP only now after PASS/WEBIRC, we have to check
	 * here again...
	 */
	check_banned(client, 0);
}

/* WEBIRC <pass> "cgiirc" <hostname> <ip> [:option1 [option2...]]*/
CMD_FUNC(cmd_webirc)
{
	const char *ip, *host, *password, *options;
	ConfigItem_webirc *e;
	char *error = NULL;

	if ((parc < 5) || BadPtr(parv[4]))
	{
		sendnumeric(client, ERR_NEEDMOREPARAMS, "WEBIRC");
		return;
	}

	password = parv[1];
	host = !DONT_RESOLVE ? parv[3] : parv[4];
	ip = parv[4];
	options = parv[5]; /* can be NULL */

	/* Check if allowed host */
	e = find_webirc(client, password, WEBIRC_WEBIRC, &error);
	if (!e)
	{
		exit_client(client, NULL, error);
		return;
	}

	/* And do our job.. */
	dowebirc(client, ip, host, options);
}

int webirc_local_pass(Client *client, const char *password)
{
	if (!strncmp(password, WEBIRC_STRING, WEBIRC_STRINGLEN))
	{
		char buf[512];
		char *ip, *host;
		ConfigItem_webirc *e;
		char *error = NULL;

		/* Work on a copy as we may trash it */
		strlcpy(buf, password, sizeof(buf));
		e = find_webirc(client, NULL, WEBIRC_PASS, &error);
		if (e)
		{
			/* Ok now we got that sorted out, proceed:
			 * Syntax: WEBIRC_<ip>_<resolvedhostname>
			 * The <resolvedhostname> has been checked ip->host AND host->ip by CGI:IRC itself
			 * already so we trust it.
			 */
			ip = buf + WEBIRC_STRINGLEN;
			host = strchr(ip, '_');
			if (!host)
			{
				exit_client(client, NULL, "Invalid CGI:IRC IP received");
				return HOOK_DENY;
			}
			*host++ = '\0';
		
			dowebirc(client, ip, host, NULL);
			return HOOK_DENY;
		}
		/* fallthrough if not in webirc block.. */
	}

	return HOOK_CONTINUE; /* not webirc */
}

/** Called from register_user() right after setting user +z */
int webirc_secure_connect(Client *client)
{
	/* Remove secure mode (-z) if the WEBIRC gateway did not ensure
	 * us that their [client]--[webirc gateway] connection is also
	 * secure (eg: using https)
	 */
	if (IsWEBIRC(client) && IsSecureConnect(client) && !IsWEBIRCSecure(client))
		client->umodes &= ~UMODE_SECURE;
	return 0;
}