Added custom userpackets.

A way to send and handle lossy UDP packets coming from friends.

Will be used for A/V.

toxcore/Messenger.c

@@ -43,6 +43,71 @@ static uint8_t friend_not_valid(Messenger *m, int friendnumber)
     return (unsigned int)friendnumber >= m->numfriends;
 }
 
+static int add_online_friend(Messenger *m, int friendnumber)
+{
+    if (friend_not_valid(m, friendnumber))
+        return -1;
+
+    IP_Port temp_ip_port = get_friend_ipport(m, friendnumber);
+
+    if (temp_ip_port.port == 0)
+        return -1;
+
+    uint32_t i;
+
+    for (i = 0; i < m->numonline_friends; ++i) {
+        if (m->online_friendlist[i].friend_num == (uint32_t)friendnumber)
+            return 0;
+    }
+
+    Online_Friend *temp;
+    temp = realloc(m->online_friendlist, sizeof(Online_Friend) * (m->numonline_friends + 1));
+
+    if (temp == NULL)
+        return -1;
+
+    m->online_friendlist = temp;
+    m->online_friendlist[m->numonline_friends].friend_num = friendnumber;
+    m->online_friendlist[m->numonline_friends].ip_port = temp_ip_port;
+    ++m->numonline_friends;
+    return 0;
+}
+
+
+static int remove_online_friend(Messenger *m, int friendnumber)
+{
+    uint32_t i;
+    Online_Friend *temp;
+
+    for (i = 0; i < m->numonline_friends; ++i) {
+        /* Equal */
+        if (m->online_friendlist[i].friend_num == (uint32_t)friendnumber) {
+            --m->numonline_friends;
+
+            if (m->numonline_friends != i) {
+                memcpy( &m->online_friendlist[i],
+                        &m->online_friendlist[m->numonline_friends],
+                        sizeof(Online_Friend) );
+            }
+
+            if (m->numonline_friends == 0) {
+                free(m->online_friendlist);
+                m->online_friendlist = NULL;
+                return 0;
+            }
+
+            temp = realloc(m->online_friendlist, sizeof(Online_Friend) * (m->numonline_friends));
+
+            if (temp == NULL)
+                return -1;
+
+            m->online_friendlist = temp;
+            return 0;
+        }
+    }
+
+    return -1;
+}
 /* Set the size of the friend list to numfriends.
  *
  *  return -1 if realloc fails.
@@ -274,7 +339,7 @@ int m_delfriend(Messenger *m, int friendnumber)
         return -1;
 
     if (m->friendlist[friendnumber].status == FRIEND_ONLINE)
-        --m->numonline_friends;
+        remove_online_friend(m, friendnumber);
 
     onion_delfriend(m->onion_c, m->friendlist[friendnumber].onion_friendnum);
     crypto_kill(m->net_crypto, m->friendlist[friendnumber].crypt_connection_id);
@@ -670,9 +735,9 @@ static void check_friend_connectionstatus(Messenger *m, int friendnumber, uint8_
     if (is_online != was_online) {
         if (was_online) {
             break_files(m, friendnumber);
-            --m->numonline_friends;
+            remove_online_friend(m, friendnumber);
         } else {
-            ++m->numonline_friends;
+            add_online_friend(m, friendnumber);
         }
 
         m->friend_connectionstatuschange(m, friendnumber, is_online, m->friend_connectionstatuschange_userdata);
@@ -1500,6 +1565,60 @@ int m_msi_packet(Messenger *m, int friendnumber, uint8_t *data, uint16_t length)
     return write_cryptpacket_id(m, friendnumber, PACKET_ID_MSI, data, length);
 }
 
+static int friendnum_from_ip_port(Messenger *m, IP_Port ip_port)
+{
+    uint32_t i;
+
+    for (i = 0; i < m->numonline_friends; ++i) {
+        if (ipport_equal(&m->online_friendlist[i].ip_port, &ip_port))
+            return m->online_friendlist[i].friend_num;
+    }
+
+    return -1;
+}
+
+static int handle_custom_user_packet(void *object, IP_Port source, uint8_t *packet, uint32_t length)
+{
+    Messenger *m = object;
+    int friend_num = friendnum_from_ip_port(m, source);
+
+    if (friend_num == -1)
+        return 1;
+
+    if (m->friendlist[friend_num].packethandlers[packet[0] % TOTAL_USERPACKETS].function)
+        return m->friendlist[friend_num].packethandlers[packet[0] % TOTAL_USERPACKETS].function(
+                   m->friendlist[friend_num].packethandlers[packet[0] % TOTAL_USERPACKETS].object, source, packet, length);
+
+    return 1;
+}
+
+
+int custom_user_packet_registerhandler(Messenger *m, int friendnumber, uint8_t byte, packet_handler_callback cb,
+                                       void *object)
+{
+    if (friend_not_valid(m, friendnumber))
+        return -1;
+
+    if (byte < NET_PACKET_CUSTOM_RANGE_START || byte >= NET_PACKET_CUSTOM_RANGE_END)
+        return -1;
+
+    m->friendlist[friendnumber].packethandlers[byte % TOTAL_USERPACKETS].function = cb;
+    m->friendlist[friendnumber].packethandlers[byte % TOTAL_USERPACKETS].object = object;
+    networking_registerhandler(m->net, byte, handle_custom_user_packet, m);
+    return 0;
+}
+
+int send_custom_user_packet(Messenger *m, int friendnumber, uint8_t *data, uint32_t length)
+{
+    IP_Port ip_port = get_friend_ipport(m, friendnumber);
+
+    if (ip_port.port == 0)
+        return -1;
+
+    return sendpacket(m->net, ip_port, data, length);
+}
+
+
 /* Function to filter out some friend requests*/
 static int friend_already_added(uint8_t *client_id, void *data)
 {

toxcore/Messenger.h

@@ -155,8 +155,15 @@ typedef struct {
     struct File_Transfers file_receiving[MAX_CONCURRENT_FILE_PIPES];
     int invited_groups[MAX_INVITED_GROUPS];
     uint16_t invited_groups_num;
+
+    Packet_Handles packethandlers[TOTAL_USERPACKETS];
 } Friend;
 
+typedef struct {
+    uint32_t friend_num;
+    IP_Port ip_port;
+} Online_Friend;
+
 typedef struct Messenger {
 
     Networking_Core *net;
@@ -178,6 +185,8 @@ typedef struct Messenger {
 
     Friend *friendlist;
     uint32_t numfriends;
+
+    Online_Friend *online_friendlist;
     uint32_t numonline_friends;
 
     Group_Chat **chats;
@@ -628,6 +637,22 @@ int m_msi_packet(Messenger *m, int friendnumber, uint8_t *data, uint16_t length)
 
 /**********************************************/
 
+/* Set handlers for custom user packets (RTP packets for example.)
+ *
+ * return -1 on failure.
+ * return 0 on success.
+ */
+int custom_user_packet_registerhandler(Messenger *m, int friendnumber, uint8_t byte, packet_handler_callback cb,
+                                       void *object);
+
+/* High level function to send custom user packets.
+ *
+ * return -1 on failure.
+ * return number of bytes sent on success.
+ */
+int send_custom_user_packet(Messenger *m, int friendnumber, uint8_t *data, uint32_t length);
+
+/**********************************************/
 /* Run this at startup.
  *  return allocated instance of Messenger on success.
  *  return 0 if there are problems.

toxcore/network.h

@@ -129,6 +129,12 @@ typedef int sock_t;
 #define NET_PACKET_LAN_DISCOVERY   33  /* LAN discovery packet ID. */
 #define NET_PACKET_GROUP_CHATS     48  /* Group chats packet ID. */
 
+/* Range of ids that custom user packets can use. */
+#define NET_PACKET_CUSTOM_RANGE_START 64
+#define NET_PACKET_CUSTOM_RANGE_END 96
+
+#define TOTAL_USERPACKETS (NET_PACKET_CUSTOM_RANGE_END - NET_PACKET_CUSTOM_RANGE_START)
+
 /* See:  docs/Prevent_Tracking.txt and onion.{c, h} */
 #define NET_PACKET_ONION_SEND_INITIAL 128
 #define NET_PACKET_ONION_SEND_1 129