Added function to create onion packets to send via TCP.

1 files changed, 48 insertions, 0 deletions

diff --git a/toxcore/onion.c b/toxcore/onion.c
index 33bb54ca..938b861e 100644
--- a/toxcore/onion.c
+++ b/toxcore/onion.c
@@ -141,6 +141,54 @@ int create_onion_packet(uint8_t *packet, uint16_t max_packet_length, const Onion
     return 1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + len;
 }
 
+/* Create a onion packet to be sent over tcp.
+ *
+ * Use Onion_Path path to create packet for data of length to dest.
+ * Maximum length of data is ONION_MAX_DATA_SIZE.
+ * packet should be at least ONION_MAX_PACKET_SIZE big.
+ *
+ * return -1 on failure.
+ * return length of created packet on success.
+ */
+int create_onion_packet_tcp(uint8_t *packet, uint16_t max_packet_length, const Onion_Path *path, IP_Port dest,
+                            const uint8_t *data, uint32_t length)
+{
+    if (crypto_box_NONCEBYTES + SIZE_IPPORT + SEND_BASE * 2 + length > max_packet_length || length == 0)
+        return -1;
+
+    to_net_family(&dest.ip);
+    uint8_t step1[SIZE_IPPORT + length];
+
+
+    ipport_pack(step1, &dest);
+    memcpy(step1 + SIZE_IPPORT, data, length);
+
+    uint8_t nonce[crypto_box_NONCEBYTES];
+    random_nonce(nonce);
+
+    uint8_t step2[SIZE_IPPORT + SEND_BASE + length];
+    ipport_pack(step2, &path->ip_port3);
+    memcpy(step2 + SIZE_IPPORT, path->public_key3, crypto_box_PUBLICKEYBYTES);
+
+    int len = encrypt_data_symmetric(path->shared_key3, nonce, step1, sizeof(step1),
+                                     step2 + SIZE_IPPORT + crypto_box_PUBLICKEYBYTES);
+
+    if ((uint32_t)len != SIZE_IPPORT + length + crypto_box_MACBYTES)
+        return -1;
+
+    ipport_pack(packet + crypto_box_NONCEBYTES, &path->ip_port2);
+    memcpy(packet + crypto_box_NONCEBYTES + SIZE_IPPORT, path->public_key2, crypto_box_PUBLICKEYBYTES);
+    len = encrypt_data_symmetric(path->shared_key2, nonce, step2, sizeof(step2),
+                                 packet + crypto_box_NONCEBYTES + SIZE_IPPORT + crypto_box_PUBLICKEYBYTES);
+
+    if ((uint32_t)len != SIZE_IPPORT + SEND_BASE + length + crypto_box_MACBYTES)
+        return -1;
+
+    memcpy(packet, nonce, crypto_box_NONCEBYTES);
+
+    return crypto_box_NONCEBYTES + SIZE_IPPORT + crypto_box_PUBLICKEYBYTES + len;
+}
+
 /* Create and send a onion packet.
  *
  * Use Onion_Path path to send data of length to dest.