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/* LAN_discovery.c
*
* LAN discovery implementation.
*
* Copyright (C) 2013 Tox project All Rights Reserved.
*
* This file is part of Tox.
*
* Tox 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.
*
* Tox 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 Tox. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "LAN_discovery.h"
#define MAX_INTERFACES 16
#ifdef __linux
#ifndef TOX_ENABLE_IPV6
/* Send packet to all broadcast addresses
*
* return higher than 0 on success.
* return 0 on error.
*
* TODO: Make this work with IPv6 and remove the #ifndef TOX_ENABLE_IPV6.
*/
static uint32_t send_broadcasts(Networking_Core *net, uint16_t port, uint8_t *data, uint16_t length)
{
/* Not sure how many platforms this will run on,
* so it's wrapped in __linux for now.
*/
struct sockaddr_in *sock_holder = NULL;
struct ifreq i_faces[MAX_INTERFACES];
struct ifconf ifconf;
int count = 0;
int sock = 0;
int i = 0;
/* Configure ifconf for the ioctl call. */
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
return 1;
}
memset(i_faces, 0, sizeof(struct ifreq) * MAX_INTERFACES);
ifconf.ifc_buf = (char *)i_faces;
ifconf.ifc_len = sizeof(i_faces);
count = ifconf.ifc_len / sizeof(struct ifreq);
if (ioctl(sock, SIOCGIFCONF, &ifconf) < 0) {
return 1;
}
for (i = 0; i < count; i++) {
if (ioctl(sock, SIOCGIFBRDADDR, &i_faces[i]) < 0) {
return 1;
}
/* Just to clarify where we're getting the values from. */
sock_holder = (struct sockaddr_in *)&i_faces[i].ifr_broadaddr;
if (sock_holder != NULL) {
IP_Port ip_port = {{{{sock_holder->sin_addr.s_addr}}, port, 0}};
sendpacket(net, ip_port, data, 1 + crypto_box_PUBLICKEYBYTES);
}
}
close(sock);
return 0;
}
#endif
#endif
/* Return the broadcast ip. */
static IP broadcast_ip(sa_family_t family_socket, sa_family_t family_broadcast)
{
IP ip;
ip_reset(&ip);
#ifdef TOX_ENABLE_IPV6
if (family_socket == AF_INET6) {
if (family_broadcast == AF_INET6) {
ip.family = AF_INET6;
/* FF02::1 is - according to RFC 4291 - multicast all-nodes link-local */
/* FE80::*: MUST be exact, for that we would need to look over all
* interfaces and check in which status they are */
ip.ip6.uint8[ 0] = 0xFF;
ip.ip6.uint8[ 1] = 0x02;
ip.ip6.uint8[15] = 0x01;
} else if (family_broadcast == AF_INET) {
ip.family = AF_INET6;
ip.ip6.uint32[0] = 0;
ip.ip6.uint32[1] = 0;
ip.ip6.uint32[2] = htonl(0xFFFF);
ip.ip6.uint32[3] = INADDR_BROADCAST;
}
} else if (family_socket == AF_INET) {
if (family_broadcast == AF_INET) {
ip.family = AF_INET;
ip.ip4.uint32 = INADDR_BROADCAST;
}
}
#else
if (family_socket == AF_INET)
if (family_broadcast == AF_INET)
ip.uint32 = INADDR_BROADCAST;
#endif
return ip;
}
/* return 0 if ip is a LAN ip.
* return -1 if it is not.
*/
static int LAN_ip(IP ip)
{
#ifdef TOX_ENABLE_IPV6
if (ip.family == AF_INET) {
IP4 ip4 = ip.ip4;
#else
IP4 ip4 = ip;
#endif
/* Loopback. */
if (ip4.uint8[0] == 127)
return 0;
/* 10.0.0.0 to 10.255.255.255 range. */
if (ip4.uint8[0] == 10)
return 0;
/* 172.16.0.0 to 172.31.255.255 range. */
if (ip4.uint8[0] == 172 && ip4.uint8[1] >= 16 && ip4.uint8[1] <= 31)
return 0;
/* 192.168.0.0 to 192.168.255.255 range. */
if (ip4.uint8[0] == 192 && ip4.uint8[1] == 168)
return 0;
/* 169.254.1.0 to 169.254.254.255 range. */
if (ip4.uint8[0] == 169 && ip4.uint8[1] == 254 && ip4.uint8[2] != 0
&& ip4.uint8[2] != 255)
return 0;
#ifdef TOX_ENABLE_IPV6
} else if (ip.family == AF_INET6)
{
/* autogenerated for each interface: FE80::* (up to FEBF::*)
FF02::1 is - according to RFC 4291 - multicast all-nodes link-local */
if (((ip.ip6.uint8[0] == 0xFF) && (ip.ip6.uint8[1] < 3) && (ip.ip6.uint8[15] == 1)) ||
((ip.ip6.uint8[0] == 0xFE) && ((ip.ip6.uint8[1] & 0xC0) == 0x80)))
return 0;
/* embedded IPv4-in-IPv6 */
if (IN6_IS_ADDR_V4MAPPED(&ip.ip6.in6_addr)) {
IP ip4;
ip4.family = AF_INET;
ip4.ip4.uint32 = ip.ip6.uint32[3];
return LAN_ip(ip4);
}
}
#endif
return -1;
}
static int handle_LANdiscovery(void *object, IP_Port source, uint8_t *packet, uint32_t length)
{
DHT *dht = object;
if (LAN_ip(source.ip) == -1)
return 1;
if (length != crypto_box_PUBLICKEYBYTES + 1)
return 1;
DHT_bootstrap(dht, source, packet + 1);
return 0;
}
int send_LANdiscovery(uint16_t port, Net_Crypto *c)
{
uint8_t data[crypto_box_PUBLICKEYBYTES + 1];
data[0] = NET_PACKET_LAN_DISCOVERY;
memcpy(data + 1, c->self_public_key, crypto_box_PUBLICKEYBYTES);
#ifdef __linux
#ifndef TOX_ENABLE_IPV6
send_broadcasts(c->lossless_udp->net, port, data, 1 + crypto_box_PUBLICKEYBYTES);
#endif
#endif
int res = -1;
IP_Port ip_port;
ip_port.port = port;
#ifdef TOX_ENABLE_IPV6
/* IPv6 multicast */
if (c->lossless_udp->net->family == AF_INET6) {
ip_port.ip = broadcast_ip(AF_INET6, AF_INET6);
if (ip_isset(&ip_port.ip))
if (sendpacket(c->lossless_udp->net, ip_port, data, 1 + crypto_box_PUBLICKEYBYTES) > 0)
res = 1;
}
/* IPv4 broadcast (has to be IPv4-in-IPv6 mapping if socket is AF_INET6 */
ip_port.ip = broadcast_ip(c->lossless_udp->net->family, AF_INET);
#else
ip_port.ip = broadcast_ip(AF_INET, AF_INET);
#endif
if (ip_isset(&ip_port.ip))
if (sendpacket(c->lossless_udp->net, ip_port, data, 1 + crypto_box_PUBLICKEYBYTES))
res = 1;
return res;
}
void LANdiscovery_init(DHT *dht)
{
networking_registerhandler(dht->c->lossless_udp->net, NET_PACKET_LAN_DISCOVERY, &handle_LANdiscovery, dht);
}
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