/*
 * uhub - A tiny ADC p2p connection hub
 * Copyright (C) 2007-2010, Jan Vidar Krey
 *
 * 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 3 of the License, 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, see <http://www.gnu.org/licenses/>.
 *
 */

#include "uhub.h"

#define ACL_ADD_USER(S, L, V) do { ret = check_cmd_user(S, V, L, line, line_count); if (ret != 0) return ret; } while(0)
#define ACL_ADD_BOOL(S, L)    do { ret = check_cmd_bool(S,    L, line, line_count); if (ret != 0) return ret; } while(0)
#define ACL_ADD_ADDR(S, L)    do { ret = check_cmd_addr(S,    L, line, line_count); if (ret != 0) return ret; } while(0)

static int check_cmd_bool(const char* cmd, struct linked_list* list, char* line, int line_count)
{
	char* data;
	
	if (!strncmp(line, cmd, strlen(cmd)))
	{
		data = &line[strlen(cmd)];
		data[0] = '\0';
		data++;
		
		data = strip_white_space(data);
		if (!*data)
		{
			LOG_FATAL("ACL parse error on line %d", line_count);
			return -1;
		}
		
		list_append(list, hub_strdup(data));
		LOG_DEBUG("ACL: Deny access for: '%s' (%s)", data, cmd);
		return 1;
	}
	return 0;
}

static int check_cmd_user(const char* cmd, int status, struct linked_list* list, char* line, int line_count)
{
	char* data;
	char* data_extra;
	struct auth_info* info = 0;

	if (!strncmp(line, cmd, strlen(cmd)))
	{
		data = &line[strlen(cmd)];
		data_extra = 0;
		data[0] = '\0';
		data++;

		data = strip_white_space(data);
		if (!*data)
		{
			LOG_FATAL("ACL parse error on line %d", line_count);
			return -1;
		}

		info = hub_malloc_zero(sizeof(struct auth_info));

		if (!info)
		{
			LOG_ERROR("ACL parse error. Out of memory!");
			return -1;
		}

		if (strncmp(cmd, "user_", 5) == 0)
		{
			data_extra = strrchr(data, ':');
			if (data_extra)
			{
				data_extra[0] = 0;
				data_extra++;
			}
		}

		strncpy(info->nickname, data, MAX_NICK_LEN);
		if (data_extra)
			strncpy(info->password, data_extra, MAX_PASS_LEN);
		info->credentials = status;
		list_append(list, info);
		LOG_DEBUG("ACL: Added user '%s' (%s)", info->nickname, auth_cred_to_string(info->credentials));
		return 1;
	}
	return 0;
}


static void add_ip_range(struct linked_list* list, struct ip_range* info)
{
	char buf1[INET6_ADDRSTRLEN+1];
	char buf2[INET6_ADDRSTRLEN+1];

	if (info->lo.af == AF_INET)
	{
		net_address_to_string(AF_INET, &info->lo.internal_ip_data.in.s_addr, buf1, INET6_ADDRSTRLEN);
		net_address_to_string(AF_INET, &info->hi.internal_ip_data.in.s_addr, buf2, INET6_ADDRSTRLEN);
	}
	else if (info->lo.af == AF_INET6)
	{
		net_address_to_string(AF_INET6, &info->lo.internal_ip_data.in6, buf1, INET6_ADDRSTRLEN);
		net_address_to_string(AF_INET6, &info->hi.internal_ip_data.in6, buf2, INET6_ADDRSTRLEN);
	}
	LOG_DEBUG("ACL: Added ip range: %s-%s", buf1, buf2);

	list_append(list, info);
}


static int check_cmd_addr(const char* cmd, struct linked_list* list, char* line, int line_count)
{
	char* data;
	struct ip_range* range = 0;

	if (!strncmp(line, cmd, strlen(cmd)))
	{
		data = &line[strlen(cmd)];
		data[0] = '\0';
		data++;

		data = strip_white_space(data);
		if (!*data)
		{
			LOG_FATAL("ACL parse error on line %d", line_count);
			return -1;
		}

		range = hub_malloc_zero(sizeof(struct ip_range));

		if (!range)
		{
			LOG_ERROR("ACL parse error. Out of memory!");
			return -1;
		}

		if (ip_convert_address_to_range(data, range))
		{
			add_ip_range(list, range);
			return 1;
		}
		hub_free(range);
	}
	return 0;
}



static int acl_parse_line(char* line, int line_count, void* ptr_data)
{
	struct acl_handle* handle = (struct acl_handle*) ptr_data;
	int ret;

	strip_off_ini_line_comments(line, line_count);

	line = strip_white_space(line);
	if (!*line)
		return 0;

	LOG_DEBUG("acl_parse_line: '%s'", line);

	ACL_ADD_USER("bot",        handle->users, auth_cred_bot);
	ACL_ADD_USER("user_admin", handle->users, auth_cred_admin);
	ACL_ADD_USER("user_super", handle->users, auth_cred_super);
	ACL_ADD_USER("user_op",    handle->users, auth_cred_operator);
	ACL_ADD_USER("user_reg",   handle->users, auth_cred_user);
	ACL_ADD_USER("link",       handle->users, auth_cred_link);
	ACL_ADD_BOOL("deny_nick",  handle->users_denied);
	ACL_ADD_BOOL("ban_nick",   handle->users_banned);
	ACL_ADD_BOOL("ban_cid",    handle->cids);
	ACL_ADD_ADDR("deny_ip",    handle->networks);
	ACL_ADD_ADDR("nat_ip",     handle->nat_override);

	LOG_ERROR("Unknown ACL command on line %d: '%s'", line_count, line);
	return -1;
}


int acl_initialize(struct hub_config* config, struct acl_handle* handle)
{
	int ret;
	memset(handle, 0, sizeof(struct acl_handle));
	
	handle->users        = list_create();
	handle->users_denied = list_create();
	handle->users_banned = list_create();
	handle->cids         = list_create();
	handle->networks     = list_create();
	handle->nat_override = list_create();
	
	if (!handle->users || !handle->cids || !handle->networks || !handle->users_denied || !handle->users_banned || !handle->nat_override)
	{
		LOG_FATAL("acl_initialize: Out of memory");
		
		list_destroy(handle->users);
		list_destroy(handle->users_denied);
		list_destroy(handle->users_banned);
		list_destroy(handle->cids);
		list_destroy(handle->networks);
		list_destroy(handle->nat_override);
		return -1;
	}
	
	if (config)
	{
		if (!*config->file_acl) return 0;
		
		ret = file_read_lines(config->file_acl, handle, &acl_parse_line);
		if (ret == -1)
			return -1;
	}
	return 0;
}


static void acl_free_access_info(void* ptr)
{
	struct auth_info* info = (struct auth_info*) ptr;
	if (info)
	{
		hub_free(info);
	}
}


static void acl_free_ip_info(void* ptr)
{
	struct access_info* info = (struct access_info*) ptr;
	if (info)
	{
		hub_free(info);
	}
}

int acl_shutdown(struct acl_handle* handle)
{
	if (handle->users)
	{
		list_clear(handle->users, &acl_free_access_info);
		list_destroy(handle->users);
	}
	
	if (handle->users_denied)
	{
		list_clear(handle->users_denied, &hub_free);
		list_destroy(handle->users_denied);
	}
	
	if (handle->users_banned)
	{
		list_clear(handle->users_banned, &hub_free);
		list_destroy(handle->users_banned);
	}
	
	
	if (handle->cids)
	{
		list_clear(handle->cids, &hub_free);
		list_destroy(handle->cids);
	}
	
	if (handle->networks)
	{
		list_clear(handle->networks, &acl_free_ip_info);
		list_destroy(handle->networks);
	}

	if (handle->nat_override)
	{
		list_clear(handle->nat_override, &acl_free_ip_info);
		list_destroy(handle->nat_override);
	}

	memset(handle, 0, sizeof(struct acl_handle));
	return 0;
}

extern int acl_register_user(struct hub_info* hub, struct auth_info* info)
{
	if (plugin_auth_register_user(hub, info) != st_allow)
	{
		return 0;
	}
	return 1;
}

extern int acl_update_user(struct hub_info* hub, struct auth_info* info)
{
	if (plugin_auth_update_user(hub, info) != st_allow)
	{
		return 0;
	}
	return 1;
}

extern int acl_delete_user(struct hub_info* hub, const char* name)
{
	struct auth_info data;
	strncpy(data.nickname, name, MAX_NICK_LEN);
	data.nickname[MAX_NICK_LEN] = '\0';
	data.password[0] = '\0';
	data.credentials = auth_cred_none;
	if (plugin_auth_delete_user(hub, &data) != st_allow)
	{
		return 0;
	}
	return 1;
}

struct auth_info* acl_get_access_info(struct hub_info* hub, const char* name)
{
	struct auth_info* info = 0;
	info = (struct auth_info*) hub_malloc(sizeof(struct auth_info));
	if (plugin_auth_get_user(hub, name, info) != st_allow)
	{
		hub_free(info);
		return NULL;
	}
	return info;
}

#define STR_LIST_CONTAINS(LIST, STR) \
		str = (char*) list_get_first(LIST); \
		while (str) \
		{ \
			if (strcasecmp(str, STR) == 0) \
				return 1; \
			str = (char*) list_get_next(LIST); \
		} \
		return 0

int acl_is_cid_banned(struct acl_handle* handle, const char* data)
{
	char* str;
	if (!handle) return 0;
	STR_LIST_CONTAINS(handle->cids, data);
}

int acl_is_user_banned(struct acl_handle* handle, const char* data)
{
	char* str;
	if (!handle) return 0;
	STR_LIST_CONTAINS(handle->users_banned, data);
}

int acl_is_user_denied(struct acl_handle* handle, const char* data)
{
	char* str;
	if (!handle) return 0;
	STR_LIST_CONTAINS(handle->users_denied, data);
}

int acl_user_ban_nick(struct acl_handle* handle, const char* nick)
{
	char* data = hub_strdup(nick);
	if (!data)
	{
		LOG_ERROR("ACL error: Out of memory!");
		return -1;
	}

	list_append(handle->users_banned, data);
	return 0;
}

int acl_user_ban_cid(struct acl_handle* handle, const char* cid)
{
	char* data = hub_strdup(cid);
	if (!data)
	{
		LOG_ERROR("ACL error: Out of memory!");
		return -1;
	}

	list_append(handle->cids, data);
	return 0;
}

int acl_user_unban_nick(struct acl_handle* handle, const char* nick)
{
	return -1;
}

int acl_user_unban_cid(struct acl_handle* handle, const char* cid)
{
	return -1;
}


int acl_is_ip_banned(struct acl_handle* handle, const char* ip_address)
{
	struct ip_addr_encap raw;
	struct ip_range* info = (struct ip_range*) list_get_first(handle->networks);
	ip_convert_to_binary(ip_address, &raw);
	
	while (info)
	{
		if (ip_in_range(&raw, info))
		{
			return 1;
		}
		info = (struct ip_range*) list_get_next(handle->networks);
	}
	return 0;
}

int acl_is_ip_nat_override(struct acl_handle* handle, const char* ip_address)
{
	struct ip_addr_encap raw;
	struct ip_range* info = (struct ip_range*) list_get_first(handle->nat_override);
	ip_convert_to_binary(ip_address, &raw);
	
	while (info)
	{
		if (ip_in_range(&raw, info))
		{
			return 1;
		}
		info = (struct ip_range*) list_get_next(handle->nat_override);
	}
	return 0;
}


/*
 * This will generate the same challenge to the same user, always.
 * The challenge is made up of the time of the user connected
 * seconds since the unix epoch (modulus 1 million)
 * and the SID of the user (0-1 million).
 */
const char* acl_password_generate_challenge(struct hub_info* hub, struct hub_user* user)
{
	char buf[64];
	uint64_t tiger_res[3];
	static char tiger_buf[MAX_CID_LEN+1];

	// FIXME: Generate a better nonce scheme.
	snprintf(buf, 64, "%p%d%d", user, (int) user->id.sid, (int) net_con_get_sd(user->connection));

	tiger((uint64_t*) buf, strlen(buf), (uint64_t*) tiger_res);
	base32_encode((unsigned char*) tiger_res, TIGERSIZE, tiger_buf);
	tiger_buf[MAX_CID_LEN] = 0;
	return (const char*) tiger_buf;
}


int acl_password_verify(struct hub_info* hub, struct hub_user* user, const char* password)
{
	char buf[1024];
	struct auth_info* access;
	const char* challenge;
	char raw_challenge[64];
	char password_calc[64];
	uint64_t tiger_res[3];
	size_t password_len;

	if (!password || !user || strlen(password) != MAX_CID_LEN)
		return 0;

	access = acl_get_access_info(hub, user->id.nick);
	if (!access)
		return 0;

	challenge = acl_password_generate_challenge(hub, user);

	base32_decode(challenge, (unsigned char*) raw_challenge, MAX_CID_LEN);

	password_len = strlen(access->password);
	
	memcpy(&buf[0], access->password, password_len);
	memcpy(&buf[password_len], raw_challenge, TIGERSIZE);
	
	tiger((uint64_t*) buf, TIGERSIZE+password_len, (uint64_t*) tiger_res);
	base32_encode((unsigned char*) tiger_res, TIGERSIZE, password_calc);
	password_calc[MAX_CID_LEN] = 0;

	hub_free(access);

	if (strcasecmp(password, password_calc) == 0)
	{
		return 1;
	}
	return 0;
}