toxcore/LAN_discovery.c
Rama master · réplica de lectura del repositorio original.
/* SPDX-License-Identifier: GPL-3.0-or-later
* Copyright © 2016-2026 The TokTok team.
* Copyright © 2013 Tox project.
*/
/**
* LAN discovery implementation.
*/
#include "LAN_discovery.h"
#if defined(_WIN32) || defined(__WIN32__) || defined(WIN32)
// The mingw32/64 Windows library warns about including winsock2.h after
// windows.h even though with the above it's a valid thing to do. So, to make
// mingw32 headers happy, we include winsock2.h first.
#include <winsock2.h>
#include <windows.h>
#include <ws2tcpip.h>
#include <iphlpapi.h>
#endif /* WIN32 */
#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
#include <netinet/in.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#endif /* Linux/BSD */
#ifdef __linux__
#include <linux/if.h>
#endif /* Linux */
#if defined(__FreeBSD__) || defined(__DragonFly__)
#include <net/if.h>
#endif /* BSD */
#include "attributes.h"
#include "ccompat.h"
#include "crypto_core.h"
#include "mem.h"
#include "network.h"
#define MAX_INTERFACES 16
struct Broadcast_Info {
const Memory *_Nonnull mem;
uint32_t count;
IP ips[MAX_INTERFACES];
};
#if defined(_WIN32) || defined(__WIN32__) || defined(WIN32)
static Broadcast_Info *_Nullable fetch_broadcast_info(const Memory *_Nonnull mem, const Network *_Nonnull ns)
{
Broadcast_Info *broadcast = (Broadcast_Info *)mem_alloc(mem, sizeof(Broadcast_Info));
if (broadcast == nullptr) {
return nullptr;
}
broadcast->mem = mem;
IP_ADAPTER_INFO *adapter_info = (IP_ADAPTER_INFO *)mem_balloc(mem, sizeof(IP_ADAPTER_INFO));
if (adapter_info == nullptr) {
mem_delete(mem, broadcast);
return nullptr;
}
unsigned long out_buf_len = sizeof(IP_ADAPTER_INFO);
if (GetAdaptersInfo(adapter_info, &out_buf_len) == ERROR_BUFFER_OVERFLOW) {
mem_delete(mem, adapter_info);
IP_ADAPTER_INFO *new_adapter_info = (IP_ADAPTER_INFO *)mem_balloc(mem, out_buf_len);
if (new_adapter_info == nullptr) {
mem_delete(mem, broadcast);
return nullptr;
}
adapter_info = new_adapter_info;
}
const int ret = GetAdaptersInfo(adapter_info, &out_buf_len);
if (ret == NO_ERROR) {
IP_ADAPTER_INFO *adapter = adapter_info;
while (adapter != nullptr) {
IP if_ip = {0};
IP subnet_mask = {0};
if (addr_parse_ip(adapter->IpAddressList.IpMask.String, &subnet_mask)
&& addr_parse_ip(adapter->IpAddressList.IpAddress.String, &if_ip)) {
if (net_family_is_ipv4(if_ip.family) && net_family_is_ipv4(subnet_mask.family)) {
if (if_ip.ip.v4.uint32 != 0 && subnet_mask.ip.v4.uint32 != 0) {
IP *ip = &broadcast->ips[broadcast->count];
ip->family = net_family_ipv4();
ip->ip.v4.uint32 = if_ip.ip.v4.uint32 | ~subnet_mask.ip.v4.uint32;
++broadcast->count;
if (broadcast->count >= MAX_INTERFACES) {
break;
}
}
}
}
adapter = adapter->Next;
}
}
if (adapter_info != nullptr) {
mem_delete(mem, adapter_info);
}
return broadcast;
}
#elif !defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && (defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__))
static bool ip4_is_local(const IP4 *_Nonnull ip4);
static Broadcast_Info *_Nullable fetch_broadcast_info(const Memory *_Nonnull mem, const Network *_Nonnull ns)
{
Broadcast_Info *broadcast = (Broadcast_Info *)mem_alloc(mem, sizeof(Broadcast_Info));
if (broadcast == nullptr) {
return nullptr;
}
broadcast->mem = mem;
/* Not sure how many platforms this will run on,
* so it's wrapped in `__linux__` for now.
* Definitely won't work like this on Windows...
*/
const Socket sock = net_socket(ns, net_family_ipv4(), TOX_SOCK_STREAM, 0);
if (!sock_valid(sock)) {
mem_delete(mem, broadcast);
return nullptr;
}
/* Configure ifconf for the ioctl call. */
struct ifreq i_faces[MAX_INTERFACES] = {{{0}}};
struct ifconf ifc;
ifc.ifc_buf = (char *)i_faces;
ifc.ifc_len = sizeof(i_faces);
if (ioctl(net_socket_to_native(sock), SIOCGIFCONF, &ifc) < 0) {
kill_sock(ns, sock);
mem_delete(mem, broadcast);
return nullptr;
}
/* `ifc.ifc_len` is set by the `ioctl()` to the actual length used.
* On usage of the complete array the call should be repeated with
* a larger array, not done (640kB and 16 interfaces shall be
* enough, for everybody!)
*/
const int n = ifc.ifc_len / sizeof(struct ifreq);
for (int i = 0; i < n; ++i) {
/* there are interfaces with are incapable of broadcast
* on Linux, `lo` has no broadcast address, but this function returns `>=0` */
if (ioctl(net_socket_to_native(sock), SIOCGIFBRDADDR, &i_faces[i]) < 0) {
continue;
}
/* moot check: only AF_INET returned (backwards compat.) */
if (i_faces[i].ifr_broadaddr.sa_family != AF_INET) {
continue;
}
const struct sockaddr_in *broadaddr4 = (const struct sockaddr_in *)(void *)&i_faces[i].ifr_broadaddr;
if (broadcast->count >= MAX_INTERFACES) {
break;
}
IP *ip = &broadcast->ips[broadcast->count];
ip->family = net_family_ipv4();
ip->ip.v4.uint32 = broadaddr4->sin_addr.s_addr;
// if no broadcast address
if (ip->ip.v4.uint32 == 0) {
if (ioctl(net_socket_to_native(sock), SIOCGIFADDR, &i_faces[i]) < 0) {
continue;
}
const struct sockaddr_in *addr4 = (const struct sockaddr_in *)(void *)&i_faces[i].ifr_addr;
IP4 ip4_staging;
ip4_staging.uint32 = addr4->sin_addr.s_addr;
if (ip4_is_local(&ip4_staging)) {
// this is 127.x.x.x
ip->ip.v4.uint32 = ip4_staging.uint32;
} else {
// give up.
continue;
}
}
++broadcast->count;
}
kill_sock(ns, sock);
return broadcast;
}
#else // TODO(irungentoo): Other platforms?
static Broadcast_Info *_Nullable fetch_broadcast_info(const Memory *_Nonnull mem, const Network *_Nonnull ns)
{
Broadcast_Info *broadcast = (Broadcast_Info *)mem_alloc(mem, sizeof(Broadcast_Info));
if (broadcast == nullptr) {
return nullptr;
}
broadcast->mem = mem;
return broadcast;
}
#endif /* platforms */
/** @brief Send packet to all IPv4 broadcast addresses
*
* @retval true if sent to at least one broadcast target.
* @retval false on failure to find any valid broadcast target.
*/
static bool send_broadcasts(const Networking_Core *_Nonnull net, const Broadcast_Info *_Nonnull broadcast, uint16_t port, const uint8_t *_Nonnull data, uint16_t length)
{
if (broadcast->count == 0) {
return false;
}
for (uint32_t i = 0; i < broadcast->count; ++i) {
IP_Port ip_port;
ip_port.ip = broadcast->ips[i];
ip_port.port = port;
sendpacket(net, &ip_port, data, length);
}
return true;
}
/** Return the broadcast ip. */
static IP broadcast_ip(Family family_socket, Family family_broadcast)
{
IP ip;
ip_reset(&ip);
if (net_family_is_ipv6(family_socket)) {
if (net_family_is_ipv6(family_broadcast)) {
ip.family = net_family_ipv6();
/* `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.ip.v6.uint8[0] = 0xFF;
ip.ip.v6.uint8[1] = 0x02;
ip.ip.v6.uint8[15] = 0x01;
} else if (net_family_is_ipv4(family_broadcast)) {
ip.family = net_family_ipv6();
ip.ip.v6 = get_ip6_broadcast();
}
} else if (net_family_is_ipv4(family_socket) && net_family_is_ipv4(family_broadcast)) {
ip.family = net_family_ipv4();
ip.ip.v4 = get_ip4_broadcast();
}
return ip;
}
static bool ip4_is_local(const IP4 *ip4)
{
/* Loopback. */
return ip4->uint8[0] == 127;
}
/**
* Is IP a local ip or not.
*/
bool ip_is_local(const IP *ip)
{
if (net_family_is_ipv4(ip->family)) {
return ip4_is_local(&ip->ip.v4);
}
/* embedded IPv4-in-IPv6 */
if (ipv6_ipv4_in_v6(&ip->ip.v6)) {
IP4 ip4;
ip4.uint32 = ip->ip.v6.uint32[3];
return ip4_is_local(&ip4);
}
/* localhost in IPv6 (::1) */
return ip->ip.v6.uint64[0] == 0 && ip->ip.v6.uint32[2] == 0 && ip->ip.v6.uint32[3] == net_htonl(1);
}
static bool ip4_is_lan(const IP4 *_Nonnull ip4)
{
/* 10.0.0.0 to 10.255.255.255 range. */
if (ip4->uint8[0] == 10) {
return true;
}
/* 172.16.0.0 to 172.31.255.255 range. */
if (ip4->uint8[0] == 172 && ip4->uint8[1] >= 16 && ip4->uint8[1] <= 31) {
return true;
}
/* 192.168.0.0 to 192.168.255.255 range. */
if (ip4->uint8[0] == 192 && ip4->uint8[1] == 168) {
return true;
}
/* 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 true;
}
/* RFC 6598: 100.64.0.0 to 100.127.255.255 (100.64.0.0/10)
* (shared address space to stack another layer of NAT) */
return (ip4->uint8[0] == 100) && ((ip4->uint8[1] & 0xC0) == 0x40);
}
bool ip_is_lan(const IP *ip)
{
if (ip_is_local(ip)) {
return true;
}
if (net_family_is_ipv4(ip->family)) {
return ip4_is_lan(&ip->ip.v4);
}
if (net_family_is_ipv6(ip->family)) {
/* autogenerated for each interface: `FE80::*` (up to `FEBF::*`)
* `FF02::1` is - according to RFC 4291 - multicast all-nodes link-local */
if (((ip->ip.v6.uint8[0] == 0xFF) && (ip->ip.v6.uint8[1] < 3) && (ip->ip.v6.uint8[15] == 1)) ||
((ip->ip.v6.uint8[0] == 0xFE) && ((ip->ip.v6.uint8[1] & 0xC0) == 0x80))) {
return true;
}
/* embedded IPv4-in-IPv6 */
if (ipv6_ipv4_in_v6(&ip->ip.v6)) {
IP4 ip4;
ip4.uint32 = ip->ip.v6.uint32[3];
return ip4_is_lan(&ip4);
}
}
return false;
}
bool lan_discovery_send(const Networking_Core *net, const Broadcast_Info *broadcast, const uint8_t *dht_pk,
uint16_t port)
{
if (broadcast == nullptr) {
return false;
}
uint8_t data[CRYPTO_PUBLIC_KEY_SIZE + 1];
data[0] = NET_PACKET_LAN_DISCOVERY;
pk_copy(data + 1, dht_pk);
send_broadcasts(net, broadcast, port, data, 1 + CRYPTO_PUBLIC_KEY_SIZE);
bool res = false;
IP_Port ip_port;
ip_port.port = port;
/* IPv6 multicast */
if (net_family_is_ipv6(net_family(net))) {
ip_port.ip = broadcast_ip(net_family_ipv6(), net_family_ipv6());
if (ip_isset(&ip_port.ip) && sendpacket(net, &ip_port, data, 1 + CRYPTO_PUBLIC_KEY_SIZE) > 0) {
res = true;
}
}
/* IPv4 broadcast (has to be IPv4-in-IPv6 mapping if socket is IPv6 */
ip_port.ip = broadcast_ip(net_family(net), net_family_ipv4());
if (ip_isset(&ip_port.ip) && sendpacket(net, &ip_port, data, 1 + CRYPTO_PUBLIC_KEY_SIZE) > 0) {
res = true;
}
return res;
}
Broadcast_Info *lan_discovery_init(const Memory *mem, const Network *ns)
{
return fetch_broadcast_info(mem, ns);
}
void lan_discovery_kill(Broadcast_Info *broadcast)
{
if (broadcast == nullptr) {
return;
}
mem_delete(broadcast->mem, broadcast);
}