Assign some TCP relays for use with onion packets and keep them connected

for that purpose.

3 files changed, 22 insertions, 6 deletions

diff --git a/toxcore/TCP_connection.c b/toxcore/TCP_connection.c
index ab18daac..574ae3aa 100644
--- a/toxcore/TCP_connection.c
+++ b/toxcore/TCP_connection.c
@@ -274,13 +274,14 @@ int send_packet_tcp_connection(TCP_Connections *tcp_c, int connections_number, c
  * return TCP connection number on success.
  * return -1 on failure.
  */
-int get_random_tcp_conn_number(TCP_Connections *tcp_c)
+int get_random_tcp_onion_conn_number(TCP_Connections *tcp_c)
 {
     unsigned int i, r = rand();
 
     for (i = 0; i < tcp_c->tcp_connections_length; ++i) {
-        if (tcp_c->tcp_connections[(i + r) % tcp_c->tcp_connections_length].status == TCP_CONN_CONNECTED) {
-            return ((i + r) % tcp_c->tcp_connections_length);
+        unsigned int index = ((i + r) % tcp_c->tcp_connections_length);
+        if (tcp_c->tcp_connections[index].onion && tcp_c->tcp_connections[index].status == TCP_CONN_CONNECTED) {
+            return index;
         }
     }
 
@@ -579,6 +580,10 @@ static int kill_tcp_relay_connection(TCP_Connections *tcp_c, int tcp_connections
         }
     }
 
+    if (tcp_con->onion) {
+        --tcp_c->onion_num_conns;
+    }
+
     kill_TCP_connection(tcp_con->connection);
 
     return wipe_tcp_connection(tcp_c, tcp_connections_number);
@@ -777,6 +782,11 @@ static int tcp_relay_on_online(TCP_Connections *tcp_c, int tcp_connections_numbe
         tcp_con->connected_time = 0;
     }
 
+    if (tcp_c->onion_num_conns < NUM_ONION_TCP_CONNECTIONS) {
+        tcp_con->onion = 1;
+        ++tcp_c->onion_num_conns;
+    }
+
     return 0;
 }
 
@@ -978,7 +988,7 @@ static void kill_nonused_tcp(TCP_Connections *tcp_c)
 
         if (tcp_con) {
             if (tcp_con->status == TCP_CONN_CONNECTED) {
-                if (!tcp_con->lock_count && is_timeout(tcp_con->connected_time, TCP_CONNECTION_ANNOUNCE_TIMEOUT)) {
+                if (!tcp_con->onion && !tcp_con->lock_count && is_timeout(tcp_con->connected_time, TCP_CONNECTION_ANNOUNCE_TIMEOUT)) {
                     to_kill[num_kill] = i;
                     ++num_kill;
                 }
diff --git a/toxcore/TCP_connection.h b/toxcore/TCP_connection.h
index 07d7820c..9b82e575 100644
--- a/toxcore/TCP_connection.h
+++ b/toxcore/TCP_connection.h
@@ -43,6 +43,9 @@
    NOTE: Must be at most (MAX_FRIEND_TCP_CONNECTIONS / 2) */
 #define RECOMMENDED_FRIEND_TCP_CONNECTIONS (MAX_FRIEND_TCP_CONNECTIONS / 2)
 
+/* Number of TCP connections used for onion purposes. */
+#define NUM_ONION_TCP_CONNECTIONS RECOMMENDED_FRIEND_TCP_CONNECTIONS
+
 typedef struct {
     uint8_t status;
     uint8_t public_key[crypto_box_PUBLICKEYBYTES]; /* The dht public key of the peer */
@@ -61,6 +64,7 @@ typedef struct {
     TCP_Client_Connection *connection;
     uint64_t connected_time;
     uint32_t lock_count;
+    _Bool onion;
 } TCP_con;
 
 typedef struct {
@@ -83,6 +87,8 @@ typedef struct {
     void *tcp_onion_callback_object;
 
     TCP_Proxy_Info proxy_info;
+
+    uint16_t onion_num_conns;
 } TCP_Connections;
 
 /* Send a packet to the TCP connection.
@@ -100,7 +106,7 @@ int send_packet_tcp_connection(TCP_Connections *tcp_c, int connections_number, c
  * return TCP connection number on success.
  * return -1 on failure.
  */
-int get_random_tcp_conn_number(TCP_Connections *tcp_c);
+int get_random_tcp_onion_conn_number(TCP_Connections *tcp_c);
 
 /* Send an onion packet via the TCP relay corresponding to tcp_connections_number.
  *
diff --git a/toxcore/net_crypto.c b/toxcore/net_crypto.c
index c93f4f41..784e8102 100644
--- a/toxcore/net_crypto.c
+++ b/toxcore/net_crypto.c
@@ -1785,7 +1785,7 @@ int add_tcp_relay(Net_Crypto *c, IP_Port ip_port, const uint8_t *public_key)
 int get_random_tcp_con_number(Net_Crypto *c)
 {
     pthread_mutex_lock(&c->tcp_mutex);
-    int ret = get_random_tcp_conn_number(c->tcp_c);
+    int ret = get_random_tcp_onion_conn_number(c->tcp_c);
     pthread_mutex_unlock(&c->tcp_mutex);
 
     return ret;