/* Prosody IM

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

-- Copyright (C) 2012 Paul Aurich

-- Copyright (C) 2013 Matthew Wild

-- Copyright (C) 2013 Florian Zeitz

--

*/

#ifndef _GNU_SOURCE

#define _GNU_SOURCE

#endif

#include <stddef.h>

#include <string.h>

#include <errno.h>

#ifndef _WIN32

#include <sys/ioctl.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <net/if.h>

#include <ifaddrs.h>

#include <arpa/inet.h>

#include <netinet/in.h>

#endif

#include <lua.h>

#include <lauxlib.h>

#if (LUA_VERSION_NUM == 501)

#define luaL_setfuncs(L, R, N) luaL_register(L, NULL, R)

#endif

#if (LUA_VERSION_NUM < 504)

#define luaL_pushfail lua_pushnil

#endif

/* Enumerate all locally configured IP addresses */

static const char *const type_strings[] = {

	"both",

	"ipv4",

	"ipv6",

	NULL

};

static int lc_local_addresses(lua_State *L) {

#ifndef _WIN32

	/* Link-local IPv4 addresses; see RFC 3927 and RFC 5735 */

	const uint32_t ip4_linklocal = htonl(0xa9fe0000); /* 169.254.0.0 */

	const uint32_t ip4_mask      = htonl(0xffff0000);

	struct ifaddrs *addr = NULL, *a;

#endif

	int n = 1;

	int type = luaL_checkoption(L, 1, "both", type_strings);

	const char link_local = lua_toboolean(L, 2); /* defaults to 0 (false) */

	const char ipv4 = (type == 0 || type == 1);

	const char ipv6 = (type == 0 || type == 2);

#ifndef _WIN32

	if(getifaddrs(&addr) < 0) {

		luaL_pushfail(L);

		lua_pushfstring(L, "getifaddrs failed (%d): %s", errno,

		                strerror(errno));

		return 2;

	}

#endif

	lua_newtable(L);

#ifndef _WIN32

	for(a = addr; a; a = a->ifa_next) {

		int family;

		char ipaddr[INET6_ADDRSTRLEN];

		const char *tmp = NULL;

		if(a->ifa_addr == NULL || a->ifa_flags & IFF_LOOPBACK) {

			continue;

		}

		family = a->ifa_addr->sa_family;

		if(ipv4 && family == AF_INET) {

			struct sockaddr_in *sa = (struct sockaddr_in *)a->ifa_addr;

			if(!link_local && ((sa->sin_addr.s_addr & ip4_mask) == ip4_linklocal)) {

				continue;

			}

			tmp = inet_ntop(family, &sa->sin_addr, ipaddr, sizeof(ipaddr));

		} else if(ipv6 && family == AF_INET6) {

			struct sockaddr_in6 *sa = (struct sockaddr_in6 *)a->ifa_addr;

			if(!link_local && IN6_IS_ADDR_LINKLOCAL(&sa->sin6_addr)) {

				continue;

			}

			if(IN6_IS_ADDR_V4MAPPED(&sa->sin6_addr) || IN6_IS_ADDR_V4COMPAT(&sa->sin6_addr)) {

				continue;

			}

			tmp = inet_ntop(family, &sa->sin6_addr, ipaddr, sizeof(ipaddr));

		}

		if(tmp != NULL) {

			lua_pushstring(L, tmp);

			lua_rawseti(L, -2, n++);

		}

		/* TODO: Error reporting? */

	}

	freeifaddrs(addr);

#else

	if(ipv4) {

		lua_pushstring(L, "0.0.0.0");

		lua_rawseti(L, -2, n++);

	}

	if(ipv6) {

		lua_pushstring(L, "::");

		lua_rawseti(L, -2, n++);

	}

#endif

	return 1;

}

static int lc_pton(lua_State *L) {

	char buf[16];

	const char *ipaddr = luaL_checkstring(L, 1);

	int errno_ = 0;

	int family = strchr(ipaddr, ':') ? AF_INET6 : AF_INET;

	switch(inet_pton(family, ipaddr, &buf)) {

		case 1:

			lua_pushlstring(L, buf, family == AF_INET6 ? 16 : 4);

			return 1;

		case -1:

			errno_ = errno;

			luaL_pushfail(L);

			lua_pushstring(L, strerror(errno_));

			lua_pushinteger(L, errno_);

			return 3;

		default:

		case 0:

			luaL_pushfail(L);

			lua_pushstring(L, strerror(EINVAL));

			lua_pushinteger(L, EINVAL);

			return 3;

	}

}

static int lc_ntop(lua_State *L) {

	char buf[INET6_ADDRSTRLEN];

	int family;

	int errno_;

	size_t l;

	const char *ipaddr = luaL_checklstring(L, 1, &l);

	if(l == 16) {

		family = AF_INET6;

	}

	else if(l == 4) {

		family = AF_INET;

	}

	else {

		luaL_pushfail(L);

		lua_pushstring(L, strerror(EAFNOSUPPORT));

		lua_pushinteger(L, EAFNOSUPPORT);

		return 3;

	}

	if(!inet_ntop(family, ipaddr, buf, INET6_ADDRSTRLEN))

	{

		errno_ = errno;

		luaL_pushfail(L);

		lua_pushstring(L, strerror(errno_));

		lua_pushinteger(L, errno_);

		return 3;

	}

	lua_pushstring(L, (const char *)(&buf));

	return 1;

}

int luaopen_util_net(lua_State *L) {

#if (LUA_VERSION_NUM > 501)

	luaL_checkversion(L);

#endif

	luaL_Reg exports[] = {

		{ "local_addresses", lc_local_addresses },

		{ "pton", lc_pton },

		{ "ntop", lc_ntop },

		{ NULL, NULL }

	};

	lua_createtable(L, 0, 1);

	luaL_setfuncs(L, exports, 0);

	return 1;

}