add src/telnet.h

1 files changed, 90 insertions, 0 deletions

diff --git a/src/telnet.h b/src/telnet.h
new file mode 100644
index 0000000..ec22139
--- /dev/null
+++ b/src/telnet.h
@@ -0,0 +1,90 @@
+#include <netinet/in.h>
+#include <poll.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+struct client {
+  char nickname[32];
+  int has_nickname;
+};
+
+// returns a socket file descriptor.
+// if connection could not be established, -1 gets returned
+int establish_connection(struct sockaddr_in addr) {
+  int sfd = socket(AF_INET, SOCK_STREAM, 0);
+  if (sfd == -1) {
+    return -1;
+  }
+  int opt = -1;
+  setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+  int bind_addr = bind(sfd, (struct sockaddr *)&addr, sizeof(addr));
+  if (bind_addr == -1) {
+    close(sfd);
+    return -1;
+  }
+  int listen_addr = listen(sfd, 100);
+  if (listen_addr == -1) {
+    close(sfd);
+    return -1;
+  }
+  return sfd;
+}
+
+// handles new telnet connections.
+// returns 0 on success and -1 on failure.
+int handle_new_connection(int sfd, struct pollfd *fds, nfds_t *nfds,
+                          struct client *clients) {
+  int conn = accept(sfd, NULL, NULL);
+  if (conn == -1)
+    return -1;
+  fds[*nfds].fd = conn;
+  fds[*nfds].events = POLLIN;
+  clients[*nfds].has_nickname = 0;
+  char *message = "Enter your nickname:\n";
+  write(fds[*nfds].fd, message, strlen(message));
+
+  (*nfds)++;
+  return 0;
+}
+
+// process message to all the connected clients.
+// returns 0 on success and -1 on failure.
+// TODO: add struct client *clients
+int process_message(struct pollfd *fds, nfds_t *nfds, struct client *clients) {
+  for (nfds_t i = 1; i < *nfds; i++) {
+    /* if client has something to say */
+    if (fds[i].revents & POLLIN) {
+      char buffer[1024]; /* create a new empty buffer */
+      ssize_t message =
+          read(fds[i].fd, buffer,
+               sizeof(buffer)); /* read the message which the client sent */
+      if (message == 0) {
+        /* close the connection if client disappeared or disconnected */
+        close(fds[i].fd);
+        fds[i] = fds[*nfds - 1]; /* move back last slot */
+        (*nfds)--;               /* size down the current array */
+        i--;
+      } else if (message == -1) {
+        /* if message of the client returns an error */
+        close(fds[i].fd);
+        fds[i] = fds[*nfds - 1]; /* move back last slot */
+        (*nfds)--;               /* size down the current array */
+        i--;
+        return -1;
+      } else {
+        if (clients[i].has_nickname == 0) {
+          
+        }
+        /* send every message bytes to the other clients */
+        for (nfds_t j = 1; j < *nfds; j++) {
+          if (j != i) {
+            write(fds[j].fd, buffer, message);
+          }
+        }
+      }
+    }
+  }
+  return 0;
+}