From 0fff7d999404ec6e68dad2b4cbc283e34c198087 Mon Sep 17 00:00:00 2001
From: irungentoo <irungentoo@gmail.com>
Date: Fri, 16 Jan 2015 21:33:11 -0500
Subject: [PATCH] Tox should work better on TCP only when some people have
 broken TCP nodes and don't update them.

Paths now try to use the same TCP node for their entire lifetime.
---
 toxcore/net_crypto.c   | 39 ++++++++++++++++++++++++++++++---------
 toxcore/net_crypto.h   | 11 +++++++++--
 toxcore/onion_client.c | 10 +++++++++-
 3 files changed, 48 insertions(+), 12 deletions(-)

diff --git a/toxcore/net_crypto.c b/toxcore/net_crypto.c
index 8af3cbbc..112931ad 100644
--- a/toxcore/net_crypto.c
+++ b/toxcore/net_crypto.c
@@ -2039,29 +2039,50 @@ int add_tcp_relay(Net_Crypto *c, IP_Port ip_port, const uint8_t *public_key)
     return -1;
 }
 
-/* Send an onion packet via a random connected TCP relay.
+/* Return a random TCP connection number for use in send_tcp_onion_request.
  *
- * return 0 on success.
+ * TODO: This number is just the index of an array that the elements can
+ * change without warning.
+ *
+ * return TCP connection number on success.
  * return -1 on failure.
  */
-int send_tcp_onion_request(Net_Crypto *c, const uint8_t *data, uint16_t length)
+int get_random_tcp_con_number(Net_Crypto *c)
 {
     unsigned int i, r = rand();
 
     for (i = 0; i < MAX_TCP_CONNECTIONS; ++i) {
         if (c->tcp_connections[(i + r) % MAX_TCP_CONNECTIONS]) {
-            pthread_mutex_lock(&c->tcp_mutex);
-            int ret = send_onion_request(c->tcp_connections[(i + r) % MAX_TCP_CONNECTIONS], data, length);
-            pthread_mutex_unlock(&c->tcp_mutex);
-
-            if (ret == 1)
-                return 0;
+            return (i + r) % MAX_TCP_CONNECTIONS;
         }
     }
 
     return -1;
 }
 
+/* Send an onion packet via the TCP relay corresponding to TCP_conn_number.
+ *
+ * return 0 on success.
+ * return -1 on failure.
+ */
+int send_tcp_onion_request(Net_Crypto *c, unsigned int TCP_conn_number, const uint8_t *data, uint16_t length)
+{
+    if (TCP_conn_number > MAX_TCP_CONNECTIONS) {
+        return -1;
+    }
+
+    if (c->tcp_connections[TCP_conn_number]) {
+        pthread_mutex_lock(&c->tcp_mutex);
+        int ret = send_onion_request(c->tcp_connections[TCP_conn_number], data, length);
+        pthread_mutex_unlock(&c->tcp_mutex);
+
+        if (ret == 1)
+            return 0;
+    }
+
+    return -1;
+}
+
 /* Set the function to be called when an onion response packet is received by one of the TCP connections.
  */
 void tcp_onion_response_handler(Net_Crypto *c, int (*tcp_onion_callback)(void *object, const uint8_t *data,
diff --git a/toxcore/net_crypto.h b/toxcore/net_crypto.h
index b9fb1747..9d699340 100644
--- a/toxcore/net_crypto.h
+++ b/toxcore/net_crypto.h
@@ -364,12 +364,19 @@ int add_tcp_relay(Net_Crypto *c, IP_Port ip_port, const uint8_t *public_key);
 void tcp_onion_response_handler(Net_Crypto *c, int (*tcp_onion_callback)(void *object, const uint8_t *data,
                                 uint16_t length), void *object);
 
-/* Send an onion packet via a random connected TCP relay.
+/* Return a random TCP connection number for use in send_tcp_onion_request.
+ *
+ * return TCP connection number on success.
+ * return -1 on failure.
+ */
+int get_random_tcp_con_number(Net_Crypto *c);
+
+/* Send an onion packet via the TCP relay corresponding to TCP_conn_number.
  *
  * return 0 on success.
  * return -1 on failure.
  */
-int send_tcp_onion_request(Net_Crypto *c, const uint8_t *data, uint16_t length);
+int send_tcp_onion_request(Net_Crypto *c, unsigned int TCP_conn_number, const uint8_t *data, uint16_t length);
 
 /* Copy a maximum of num TCP relays we are connected to to tcp_relays.
  * NOTE that the family of the copied ip ports will be set to TCP_INET or TCP_INET6.
diff --git a/toxcore/onion_client.c b/toxcore/onion_client.c
index f8d7630b..a9eb16a0 100644
--- a/toxcore/onion_client.c
+++ b/toxcore/onion_client.c
@@ -140,8 +140,15 @@ static uint16_t random_nodes_path_onion(const Onion_Client *onion_c, Node_format
             nodes[i] = onion_c->path_nodes[rand() % num_nodes];
         }
     } else {
+        int random_tcp = get_random_tcp_con_number(onion_c->c);
+
+        if (random_tcp == -1) {
+            return 0;
+        }
+
         if (num_nodes >= 2) {
             nodes[0].ip_port.ip.family = TCP_FAMILY;
+            nodes[0].ip_port.ip.ip4.uint32 = random_tcp;
 
             for (i = 1; i < max_num; ++i) {
                 nodes[i] = onion_c->path_nodes[rand() % num_nodes];
@@ -154,6 +161,7 @@ static uint16_t random_nodes_path_onion(const Onion_Client *onion_c, Node_format
                 return 0;
 
             nodes[0].ip_port.ip.family = TCP_FAMILY;
+            nodes[0].ip_port.ip.ip4.uint32 = random_tcp;
 
             for (i = 1; i < max_num; ++i) {
                 nodes[i] = onion_c->path_nodes_bs[rand() % num_nodes_bs];
@@ -301,7 +309,7 @@ static int send_onion_packet_tcp_udp(const Onion_Client *onion_c, const Onion_Pa
         if (len == -1)
             return -1;
 
-        return send_tcp_onion_request(onion_c->c, packet, len);
+        return send_tcp_onion_request(onion_c->c, path->ip_port1.ip.ip4.uint32, packet, len);
     } else {
         return -1;
     }