add NAT hole punching level to Tox API

auto_tests/dht_test.c

@@ -303,7 +303,7 @@ static void test_addto_lists(IP ip)
     Networking_Core *net = new_networking(NULL, ip, TOX_PORT_DEFAULT);
     ck_assert_msg(net != 0, "Failed to create Networking_Core");
 
-    DHT *dht = new_DHT(NULL, net);
+    DHT *dht = new_DHT(NULL, net, TOX_DHT_NAT_LEVEL_NORMAL);
     ck_assert_msg(dht != 0, "Failed to create DHT");
 
     IP_Port ip_port = { .ip = ip, .port = TOX_PORT_DEFAULT };
@@ -440,7 +440,7 @@ static void test_list_main(void)
         IP ip;
         ip_init(&ip, 1);
 
-        dhts[i] = new_DHT(NULL, new_networking(NULL, ip, DHT_DEFAULT_PORT + i));
+        dhts[i] = new_DHT(NULL, new_networking(NULL, ip, DHT_DEFAULT_PORT + i), TOX_DHT_NAT_LEVEL_NORMAL);
         ck_assert_msg(dhts[i] != 0, "Failed to create dht instances %u", i);
         ck_assert_msg(dhts[i]->net->port != DHT_DEFAULT_PORT + i, "Bound to wrong port");
     }
@@ -584,7 +584,7 @@ START_TEST(test_DHT_test)
         IP ip;
         ip_init(&ip, 1);
 
-        dhts[i] = new_DHT(NULL, new_networking(NULL, ip, DHT_DEFAULT_PORT + i));
+        dhts[i] = new_DHT(NULL, new_networking(NULL, ip, DHT_DEFAULT_PORT + i), TOX_DHT_NAT_LEVEL_NORMAL);
         ck_assert_msg(dhts[i] != 0, "Failed to create dht instances %u", i);
         ck_assert_msg(dhts[i]->net->port != DHT_DEFAULT_PORT + i, "Bound to wrong port");
     }

auto_tests/onion_test.c

@@ -144,8 +144,8 @@ START_TEST(test_basic)
     IP ip;
     ip_init(&ip, 1);
     ip.ip6.uint8[15] = 1;
-    Onion *onion1 = new_onion(new_DHT(NULL, new_networking(NULL, ip, 34567)));
-    Onion *onion2 = new_onion(new_DHT(NULL, new_networking(NULL, ip, 34568)));
+    Onion *onion1 = new_onion(new_DHT(NULL, new_networking(NULL, ip, 34567), 2));
+    Onion *onion2 = new_onion(new_DHT(NULL, new_networking(NULL, ip, 34568), 2));
     ck_assert_msg((onion1 != NULL) && (onion2 != NULL), "Onion failed initializing.");
     networking_registerhandler(onion2->net, 'I', &handle_test_1, onion2);
 
@@ -222,7 +222,7 @@ START_TEST(test_basic)
     }
 
     c_sleep(1000);
-    Onion *onion3 = new_onion(new_DHT(NULL, new_networking(NULL, ip, 34569)));
+    Onion *onion3 = new_onion(new_DHT(NULL, new_networking(NULL, ip, 34569), 2));
     ck_assert_msg((onion3 != NULL), "Onion failed initializing.");
 
     random_nonce(nonce);
@@ -285,7 +285,7 @@ static Onions *new_onions(uint16_t port)
     ip_init(&ip, 1);
     ip.ip6.uint8[15] = 1;
     Onions *on = (Onions *)malloc(sizeof(Onions));
-    DHT *dht = new_DHT(NULL, new_networking(NULL, ip, port));
+    DHT *dht = new_DHT(NULL, new_networking(NULL, ip, port), 2);
     on->onion = new_onion(dht);
     on->onion_a = new_onion_announce(dht);
     TCP_Proxy_Info inf = {{{0}}};

auto_tests/tox_many_tcp_test.c

@@ -59,7 +59,7 @@ START_TEST(test_many_clients_tcp)
         tox_options_default(&opts);
 
         if (i == 0) {
-            opts.tcp_port = TCP_RELAY_PORT;
+            opts.dht_tcp_port = TCP_RELAY_PORT;
         } else {
             opts.udp_enabled = 0;
         }
@@ -160,7 +160,7 @@ START_TEST(test_many_clients_tcp_b)
         tox_options_default(&opts);
 
         if (i < NUM_TCP_RELAYS) {
-            opts.tcp_port = TCP_RELAY_PORT + i;
+            opts.dht_tcp_port = TCP_RELAY_PORT + i;
         } else {
             opts.udp_enabled = 0;
         }

other/DHT_bootstrap.c

@@ -120,7 +120,7 @@ int main(int argc, char *argv[])
     IP ip;
     ip_init(&ip, ipv6enabled);
 
-    DHT *dht = new_DHT(NULL, new_networking(NULL, ip, PORT));
+    DHT *dht = new_DHT(NULL, new_networking(NULL, ip, PORT), 2);
     Onion *onion = new_onion(dht);
     Onion_Announce *onion_a = new_onion_announce(dht);
 

other/bootstrap_daemon/src/tox-bootstrapd.c

@@ -33,6 +33,7 @@
 #include <sys/stat.h>
 
 // toxcore
+#include "../../../toxcore/tox.h"
 #include "../../../toxcore/LAN_discovery.h"
 #include "../../../toxcore/TCP_server.h"
 #include "../../../toxcore/onion_announce.h"
@@ -243,7 +244,7 @@ int main(int argc, char *argv[])
         }
     }
 
-    DHT *dht = new_DHT(NULL, net);
+    DHT *dht = new_DHT(NULL, net, TOX_DHT_NAT_LEVEL_NORMAL);
 
     if (dht == NULL) {
         write_log(LOG_LEVEL_ERROR, "Couldn't initialize Tox DHT instance. Exiting.\n");

testing/DHT_test.c

@@ -193,7 +193,7 @@ int main(int argc, char *argv[])
     IP ip;
     ip_init(&ip, ipv6enabled);
 
-    DHT *dht = new_DHT(NULL, new_networking(NULL, ip, PORT));
+    DHT *dht = new_DHT(NULL, new_networking(NULL, ip, PORT), 2);
     printf("OUR ID: ");
     uint32_t i;
 

testing/av_test.c

@@ -231,21 +231,21 @@ static void initialize_tox(Tox **bootstrap, ToxAV **AliceAV, CallControl *AliceC
     struct Tox_Options opts;
     tox_options_default(&opts);
 
-    opts.end_port = 0;
+    opts.dht_end_port = 0;
     opts.ipv6_enabled = false;
 
     {
         TOX_ERR_NEW error;
 
-        opts.start_port = 33445;
+        opts.dht_start_port = 33445;
         *bootstrap = tox_new(&opts, &error);
         assert(error == TOX_ERR_NEW_OK);
 
-        opts.start_port = 33455;
+        opts.dht_start_port = 33455;
         Alice = tox_new(&opts, &error);
         assert(error == TOX_ERR_NEW_OK);
 
-        opts.start_port = 33465;
+        opts.dht_start_port = 33465;
         Bob = tox_new(&opts, &error);
         assert(error == TOX_ERR_NEW_OK);
     }

toxcore/DHT.c

@@ -2090,6 +2090,26 @@ static void punch_holes(DHT *dht, IP ip, uint16_t *port_list, uint16_t numports,
         return;
     }
 
+    // TODO(toktok/c-toxcore#214)
+    /* The NAT_LEVEL set here is specified by the user, higher numbers allow toxcore to be
+     * more agressive when it tries to establish a direct UDP connection to friends. Because
+     * DHT is stateless, and some routers are known to hold on to DHT routing rules longer
+     * than needed, being to agressive may exaust all routes the NAT can handle causing a DoS
+     * effect to the whole network. */
+    switch (dht->nat_hole_punching_level) {
+
+        case 0: { // None
+            return;
+        }
+
+        case 1: // Polite
+        case 2: // Normal
+        case 3: { // Aggressive
+            break;
+            // TODO(toktok/c-toxcore#266) enable other levels.
+        }
+    }
+
     uint32_t i;
     uint32_t top = dht->friends_list[friend_num].nat.punching_index + MAX_PUNCHING_PORTS;
     uint16_t firstport = port_list[0];
@@ -2575,7 +2595,7 @@ static int cryptopacket_handle(void *object, IP_Port source, const uint8_t *pack
 
 /*----------------------------------------------------------------------------------*/
 
-DHT *new_DHT(Logger *log, Networking_Core *net)
+DHT *new_DHT(Logger *log, Networking_Core *net, uint8_t nat_level)
 {
     /* init time */
     unix_time_update();
@@ -2592,6 +2612,9 @@ DHT *new_DHT(Logger *log, Networking_Core *net)
 
     dht->log = log;
     dht->net = net;
+
+    dht->nat_hole_punching_level = nat_level;
+
     dht->ping = new_ping(dht);
 
     if (dht->ping == NULL) {

toxcore/DHT.h

@@ -238,6 +238,8 @@ typedef struct {
     Logger *log;
     Networking_Core *net;
 
+    uint8_t nat_hole_punching_level;
+
     Client_data    close_clientlist[LCLIENT_LIST];
     uint64_t       close_lastgetnodes;
     uint32_t       close_bootstrap_times;
@@ -435,7 +437,7 @@ void DHT_save(DHT *dht, uint8_t *data);
 int DHT_load(DHT *dht, const uint8_t *data, uint32_t length);
 
 /* Initialize DHT. */
-DHT *new_DHT(Logger *log, Networking_Core *net);
+DHT *new_DHT(Logger *log, Networking_Core *net, uint8_t nat_level);
 
 void kill_DHT(DHT *dht);
 

toxcore/Messenger.c

@@ -1930,7 +1930,7 @@ Messenger *new_messenger(Messenger_Options *options, unsigned int *error)
         return NULL;
     }
 
-    m->dht = new_DHT(m->log, m->net);
+    m->dht = new_DHT(m->log, m->net, options->nat_level);
 
     if (m->dht == NULL) {
         kill_networking(m->net);

toxcore/Messenger.h

@@ -77,6 +77,8 @@ typedef struct {
     uint16_t port_range[2];
     uint16_t tcp_server_port;
 
+    uint8_t nat_level;
+
     logger_cb *log_callback;
     void *log_user_data;
 } Messenger_Options;

toxcore/tox.api.h

@@ -357,6 +357,32 @@ enum class PROXY_TYPE {
   SOCKS5,
 }
 
+enum class DHT_NAT_LEVEL {
+  /**
+   * Don't try to hole punch through a NAT device at all (Not Recommended).
+   */
+  NONE,
+  /**
+   * Only try small port ranges, and wait a long time between attempts.
+   * (This level currently unsupported and is equivalent to $NORMAL)
+   */
+  POLITE,
+  /**
+   * Try to establish a direct UDP connection through any supported NAT device,
+   * by "hole punching" or sending outgoing UDP packets to IP and Port we're expecting
+   * to receive data from.
+   * NORMAL is the default setting
+   */
+  NORMAL,
+  /**
+   * Aggressively try to establish a direct connection to all friends.
+   * USE WITH CAUTION, this may interfere with some poorly configured NAT devices
+   * leading to a denial of service effect to all devices behind the NAT.
+   * (This level currently unsupported and is equivalent to $NORMAL)
+   */
+  AGGRESSIVE,
+}
+
 /**
  * Type of savedata to create the Tox instance from.
  */
@@ -486,37 +512,50 @@ static class options {
       uint16_t port;
     }
 
-    /**
-     * The start port of the inclusive port range to attempt to use.
-     *
-     * If both start_port and end_port are 0, the default port range will be
-     * used: [33445, 33545].
-     *
-     * If either start_port or end_port is 0 while the other is non-zero, the
-     * non-zero port will be the only port in the range.
-     *
-     * Having start_port > end_port will yield the same behavior as if start_port
-     * and end_port were swapped.
-     */
-    uint16_t start_port;
+    namespace dht {
 
-    /**
-     * The end port of the inclusive port range to attempt to use.
-     */
-    uint16_t end_port;
+      /**
+       * The start port of the inclusive port range to attempt to use.
+       *
+       * If both start_port and end_port are 0, the default port range will be
+       * used: [33445, 33545].
+       *
+       * If either start_port or end_port is 0 while the other is non-zero, the
+       * non-zero port will be the only port in the range.
+       *
+       * Having start_port > end_port will yield the same behavior as if start_port
+       * and end_port were swapped.
+       */
+      uint16_t start_port;
 
-    /**
-     * The port to use for the TCP server (relay). If 0, the TCP server is
-     * disabled.
-     *
-     * Enabling it is not required for Tox to function properly.
-     *
-     * When enabled, your Tox instance can act as a TCP relay for other Tox
-     * instance. This leads to increased traffic, thus when writing a client
-     * it is recommended to enable TCP server only if the user has an option
-     * to disable it.
-     */
-    uint16_t tcp_port;
+      /**
+       * The end port of the inclusive port range to attempt to use.
+       */
+      uint16_t end_port;
+
+      /**
+       * The port to use for the TCP server (relay). If 0, the TCP server is
+       * disabled.
+       *
+       * Enabling it is not required for Tox to function properly.
+       *
+       * When enabled, your Tox instance can act as a TCP relay for other Tox
+       * instance. This leads to increased traffic, thus when writing a client
+       * it is recommended to enable TCP server only if the user has an option
+       * to disable it.
+       */
+      uint16_t tcp_port;
+
+      /**
+       * Sets how aggressive toxcore is allowed to be when trying to establish a direct UDP
+       * connection with friends when either are behind a NAT device.
+       *
+       * Clients should be aware of the implications of changing this from its default.
+       * Setting too low of a level could stop toxcore from creating a direct connections,
+       * and too high could cause a DoS effect for all users, on some networks.
+       */
+      DHT_NAT_LEVEL nat_level;
+    }
 
     namespace savedata {
       /**

toxcore/tox.c

@@ -128,9 +128,10 @@ ACCESSORS(bool, , udp_enabled)
 ACCESSORS(TOX_PROXY_TYPE, proxy_ , type)
 ACCESSORS(const char *, proxy_ , host)
 ACCESSORS(uint16_t, proxy_ , port)
-ACCESSORS(uint16_t, , start_port)
-ACCESSORS(uint16_t, , end_port)
-ACCESSORS(uint16_t, , tcp_port)
+ACCESSORS(uint16_t, , dht_start_port)
+ACCESSORS(uint16_t, , dht_end_port)
+ACCESSORS(uint16_t, , dht_tcp_port)
+ACCESSORS(TOX_DHT_NAT_LEVEL, , dht_nat_level)
 ACCESSORS(TOX_SAVEDATA_TYPE, savedata_, type)
 ACCESSORS(size_t, savedata_, length)
 ACCESSORS(tox_log_cb *, log_, callback)
@@ -155,6 +156,7 @@ void tox_options_default(struct Tox_Options *options)
         options->ipv6_enabled = 1;
         options->udp_enabled = 1;
         options->proxy_type = TOX_PROXY_TYPE_NONE;
+        options->dht_nat_level = TOX_DHT_NAT_LEVEL_NORMAL;
     }
 }
 
@@ -216,9 +218,10 @@ Tox *tox_new(const struct Tox_Options *options, TOX_ERR_NEW *error)
 
         m_options.ipv6enabled = options->ipv6_enabled;
         m_options.udp_disabled = !options->udp_enabled;
-        m_options.port_range[0] = options->start_port;
-        m_options.port_range[1] = options->end_port;
-        m_options.tcp_server_port = options->tcp_port;
+        m_options.port_range[0] = options->dht_start_port;
+        m_options.port_range[1] = options->dht_end_port;
+        m_options.tcp_server_port = options->dht_tcp_port;
+        m_options.nat_level = options->dht_nat_level;
 
         m_options.log_callback = (logger_cb *)options->log_callback;
         m_options.log_user_data = options->log_user_data;