implemented message delays in read_socket_raw

include/chat/flags.h

@@ -89,6 +89,9 @@ void why2_chat_set_client_server_key(char *key); //SET KEY USED FOR ENCRYPTION B
 char *why2_chat_get_client_server_key(void);
 void why2_chat_deallocate_client_server_key(void);
 
+void __why2_chat_set_server(why2_bool value); //IF PROGRAM IS SERVER-SIDE
+why2_bool __why2_chat_is_server(void); //IF PROGRAM IS SERVER-SIDE
+
 void __why2_set_asking_password(why2_bool value); //IF HASH SHOULD BE SENT INSTEAD OF NORMAL MESSAGE
 why2_bool __why2_get_asking_password(void);
 

src/chat/config/server.toml

@@ -26,4 +26,6 @@ min_username_length = 4 # Minimal username length
 max_username_tries = 3 # Times asking client for username (if client tries to use invalid username)
 max_password_tries = 3 # Same as above but for invalid password
 
-max_message_length = 100 # Maximal message length
+max_message_length = 100 # Maximal message length
+min_message_delay = 250 # Minimal ms delay between user messages (to prevent spamming)
+max_message_delay_violations = 4 # Maximal 'spam' messages that can be sent in row without getting disconnected

src/chat/flags.c

@@ -25,6 +25,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 why2_bool asking_password = 0;
 why2_bool asking_username = 0;
+why2_bool is_server = 0;
 char *client_server_key = NULL;
 
 void why2_chat_set_client_server_key(char *key)
@@ -43,6 +44,16 @@ void why2_chat_deallocate_client_server_key(void)
     client_server_key = NULL;
 }
 
+void __why2_chat_set_server(why2_bool value)
+{
+    is_server = value;
+}
+
+why2_bool __why2_chat_is_server(void)
+{
+    return is_server;
+}
+
 void __why2_set_asking_password(why2_bool value)
 {
     asking_password = value;

src/chat/main/authority.c

@@ -35,6 +35,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 int main(void)
 {
+    __why2_chat_set_server(1);
     why2_check_version(); //CHECK FOR UPDATES
     why2_chat_init_authority(); //CREATE AUTHORITY DIRECTORY
     why2_chat_init_keys(); //CREATE ECC KEY

src/chat/main/server.c

@@ -35,6 +35,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 int main(void)
 {
+    __why2_chat_set_server(1);
     why2_check_version(); //CHECK FOR UPDATES
     why2_chat_init_server_config(); //CREATE server.toml CONFIGURATION
     why2_chat_init_keys(); //CREATE ECC KEY

src/chat/misc.c

@@ -21,6 +21,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <ctype.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
@@ -50,6 +51,8 @@ typedef struct _connection_node
     char *username;
     unsigned long id;
     char *key; //EACH USER WILL USE DIFFERENT KEY FOR COMMUNICATION
+    struct timespec last_message_time; //USED TO PREVENT SPAMMING
+    unsigned char spam_violations; //SPAM MESSAGES IN ROW
 } connection_node_t; //SINGLE LINKED LIST
 
 typedef struct _read_socket_raw_thread_node
@@ -67,6 +70,8 @@ enum ENCRYPTION_DECRYPTION
 why2_list_t connection_list = WHY2_LIST_EMPTY;
 why2_list_t waiting_list = WHY2_LIST_EMPTY;
 
+why2_node_t *find_connection(int connection);
+
 char *get_string_from_json(struct json_object *json, char *string)
 {
     struct json_object *object;
@@ -246,6 +251,55 @@ char *read_socket_raw(int socket, char *key)
     recv(socket, wait_buffer, 1, MSG_PEEK);
     why2_deallocate(wait_buffer);
 
+    //PREVENT FROM SPAMMING
+    if (__why2_chat_is_server())
+    {
+        //VARIABLES
+        int minimal_delay_ns = server_config_int("min_message_delay") * 1000000;
+        struct timespec current_time;
+        why2_node_t *node = find_connection(socket);
+        connection_node_t *client_node;
+
+        if (node != NULL)
+        {
+            client_node = (connection_node_t*) node -> value;
+
+            //GET TIME
+            clock_gettime(CLOCK_MONOTONIC, &current_time);
+
+            //NOT THE FIRST MESSAGE
+            if (client_node -> last_message_time.tv_nsec != -1)
+            {
+                int64_t difference = (current_time.tv_sec - client_node -> last_message_time.tv_sec) * 1000000000LL + (current_time.tv_nsec - client_node -> last_message_time.tv_nsec);
+
+                if (difference < minimal_delay_ns) //USER IS SPAMMING
+                {
+                    //CHECK IF USER REACHED MAXIMUM VIOLATIONS
+                    if (client_node -> spam_violations > server_config_int("max_message_delay_violations")) return NULL;
+
+                    //WAIT UNTIL MINIMAL DELAY IS ACHIEVED
+                    struct timespec sleep_time =
+                    {
+                        .tv_sec = (minimal_delay_ns - difference) / 1000000000,
+                        .tv_nsec = (minimal_delay_ns - difference) % 1000000000
+                    };
+
+                    nanosleep(&sleep_time, NULL); //SLEEP
+
+                    //ADD VIOLATION
+                    client_node -> spam_violations++;
+                } else //USER IS NOT SPAMMING
+                {
+                    //RESET VIOLATIONS
+                    client_node -> spam_violations = 0;
+                }
+            }
+
+            //WRITE NEW TIME
+            clock_gettime(CLOCK_MONOTONIC, &client_node -> last_message_time); //GET TIME
+        }
+    }
+
     //FIND THE RECEIVED SIZE
     ioctl(socket, FIONREAD, &content_size);
 
@@ -275,6 +329,9 @@ char *read_socket_raw(int socket, char *key)
 
     encrypt_decrypt_message(&output, key, DECRYPTION); //DECRYPT
 
+    //REMOVE NON-ASCII
+    remove_non_ascii(&output);
+
     //VALIDATE JSON FORMAT
     struct json_object *json = json_tokener_parse(output);
     if (json == NULL)
@@ -897,7 +954,9 @@ void *why2_communicate_thread(void *arg)
         pthread_self(),
         why2_strdup(username),
         get_latest_id(),
-        client_server_key
+        client_server_key,
+        { -1, -1 },
+        0
     };
 
     why2_list_push(&connection_list, &node, sizeof(node)); //ADD TO LIST