By Nobel Gautam and James Wang
Dependencies can be installed by running:
$ sudo apt-get install libncurses-dev libssl-dev
Running "make" will compile the project and create a "cchat" binary in the root of the repository.
$ make
Then to start a server:
$ ./cchat -n servername
To start a client:
$ ./cchat -n clientname -c serverip
For example, running a local server and client can be done as such:
$ ./cchat -n servo
Then on another terminal
$ ./cchat -n cliento -c 127.0.0.1
If you want to quit chatting, use the /quit command. Running /quit as the client will exit the program, but
running it as the server will terminate the existing connection and continue listening for more connections.
- Does not support multiple clients simultaneously.
Documentation is taken directly from the source. Run ./generate_documentation.sh to generate the documentation.
src/client/client.c:
/*
* Sends over the AES key and initialization vector to the server
* to set up end-to-end encryption
*
* Params:
* int sv_fd: File descriptor of the server to share the keys with
*/
static void exchange_keys(int sv_fd);
/*
* Share client name with the server, and receive the server's name
*
* Params:
* int cl_fd: File descriptor of the server to share the names with
*/
static void share_names(int cl_fd);
/*
* Connects to the server at the address sv_nameaddr and shares keys and names
*
* Params:
* char sv_nameaddr[64]: The address of the server, represented as a string
*
* Returns the file descriptor for the server socket
*/
static int sock_setup(char sv_nameaddr[64]);
/*
* Worker function that constantly listens for a message from the server
* Meant to be run in a thread
*
* Params:
* void *args: Struct containing the arguments server file descriptor and the list of messages
*/
static void *input(void *args);
/*
* Runs the client loop
*
* Params:
* char sv_nameaddr[64]: Server address represented as a string
* char nick[64]: The client nickname
*/
void client(char sv_nameaddr[64], char nick[64]);src/client/crypt.c:
/*
* Fills *buf* with random bytes
*/
void generate_bytes(aes_t *buf);
/*
* Uses AES encryption to encrypt *plaintext* into *ciphertext*.
*
* Params:
* char *plaintext: The plaintext to be encrypted
* aes_t *key: The key used for the encryption
* aes_t *iv: The initialization vector for the encryption
* aes_t *ciphertext: Buffer used to store the encrypted data
*
* Returns the length of the final encrypted ciphertext. Meant to be passed as a parameter to decrypt();
*/
int encrypt(char *plaintext, aes_t *key, aes_t *iv, aes_t *ciphertext);
/*
* Uses AES decryption to decrypt *ciphertext* into *plaintext*.
*
* Params:
* aes_t *ciphertext: The ciphertext to be decrypted
* aes_t *key: The key that was used for the encryption
* aes_t *iv: The initialization vector that was used for encryption
* aes_t *plaintext: Buffer used to store the decrypted data
*
* Returns the length of the plaintext if the decryption was successful, -1 otherwise
*/
int decrypt(aes_t *ciphertext, int ciphertext_len, aes_t *key, aes_t *iv, char *plaintext);src/client/main.c:
/*
* Prints the help string
*/
void help_exit();
/*
* Top-level function that gets run by the users. Parses arguments and runs
* the server or client accordingly.
*/
int main(int argc, char *argv[]);src/client/message.c:
/*
* Add a message to the list of messages
*
* msg *m - Message list to modify (must be malloc'd);
* int *m_size - Capacity of message list
* int *m_curr - Current size of message list
* char *user - Username of content author
* char *content - Message content
*/
void add_msg(msgs_data *d, char *user, char *content);
/*
* Frees the msgs_data struct and everything in it
*/
void free_msgs(msgs_data *d);src/client/notify.c:
/*
* Displays a notification using notify-send and xprop
* Only tested on Ubuntu
*/
void notify(msgs_data *d);src/client/server.c:
/*
* Reads the AES key and initialization vector from the client
* to set up end-to-end encryption
*/
static void exchange_keys(int cl_fd);
/*
* Share server name with the client, and receive the client's name
*/
static void share_names(int cl_fd);
/*
* Worker function that constantly listens for a message from a client
* Meant to be run in a thread
*/
static void *input(void *args);
/*
* Handles the server loop for a specific client
*
* Params:
* int cl_fd: File descriptor of the client to be served
*/
void serve(int cl_fd);
/*
* Runs the server loop
*
* Params:
* char nick[64]: Server nickname
*/
void server(char nick[64]);src/client/window.c:
/*
* Render the title bar
*/
void title_bar();
/*
* Draw messages onto the screen
*
* Params:
* msg *msg_list: List of messages to be drawn
* int length: Number of messages to draw
* int display_to: Index of the last message to draw
*/
void draw_messages(msg *msg_list, int length, int display_to);
/*
* Get the maximum x coordinate of the screen
*/
int get_max_x();
/*
* Draw the input prompt
*/
void draw_prompt();
/*
* Clear the screen of all messages
*/
void clear_msgs();
/*
* Update the screen, redrawing messages and the prompt
*/
void update_window(msgs_data *d);
/*
* Get input from the prompt window
*
* Params:
* char *dst: Char array used to store the input
*/
void get_input(char *dst);
/*
* Creates the initial display of the window
*/
void init_window();
/*
* Closes the screen and removes both the main and input windows
*/
void close_window();