From 422d0b0bb0e791b47c020764f62cca6a1d65e8fc Mon Sep 17 00:00:00 2001
From: "Simon V. Lejel" <sl@dcsl.dk>
Date: Tue, 13 Feb 2024 17:21:24 +0100
Subject: [PATCH] =?UTF-8?q?=F0=9F=92=A1=20Add=20more=20explanations?=
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---
 src/server/main.cc | 47 ++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 43 insertions(+), 4 deletions(-)

diff --git a/src/server/main.cc b/src/server/main.cc
index cb9f775..fca2726 100644
--- a/src/server/main.cc
+++ b/src/server/main.cc
@@ -35,17 +35,17 @@ string getCtxError() {
 
 int main() {
 
-    // Inistialize the SSL library
+    // Initializes the SSL library
     if (OpenSSL_version_num() < 0x10100000L) {
         // Old version, deprecated as of version 1.1.0
         SSL_library_init();
 
         // Loads human readable error strings
-        // Automatically inistialized in newer versions
+        // Automatically initialized in newer versions
         SSL_load_error_strings();
     } else {
         // New version
-        // Initalizes both SSl and crypto and is generally better
+        // Initializes both SSL and crypto and is generally better
         OPENSSL_init_ssl(0, nullptr);
     }
 
@@ -74,32 +74,55 @@ int main() {
     }
 
     cout << "Initializing server" << endl;
+
+    // Initializes a new TCP socket in the IPv4 family
+    // 0 tells the OS to automatically pick the correct protocol (TCP)
     int serverSocket = socket(AF_INET, SOCK_STREAM, 0);
     if (serverSocket == -1) {
         cout << "Server socket failed" << endl;
+        return serverSocket;
     }
 
     sockaddr_in serverAddress;
+
+    // Specify that we use the IPv4 family
     serverAddress.sin_family = AF_INET;
+
+    // Specify the port number
+    // htons converts it to bytes
     serverAddress.sin_port = htons(8080);
+
+    // Specify the listen address
+    // inet_addr converts the string to bytes
     serverAddress.sin_addr.s_addr = inet_addr("127.0.0.50");
 
+    // Bind the serverSocket to the serverAddress
+    // serverAddress is cast to a sockaddr
     int bindStatus = bind(serverSocket, (struct sockaddr *)&serverAddress,
                           sizeof(serverAddress));
     if (bindStatus == -1) {
         cout << "Bind failed" << endl;
+        return bindStatus;
     }
 
-    int listenStatus = listen(serverSocket, 5);
+    // Prepare to accept connections
+    // Only 1 is allowed, others will be denied as the server exits when a
+    // client leaves
+    int listenStatus = listen(serverSocket, 1);
     if (listenStatus == -1) {
         cout << "Listen failed" << endl;
+        return listenStatus;
     }
 
+    // Await connection from a client
+    // We don't need the client's address nor do we know the length of it
     int clientSocket = accept(serverSocket, nullptr, nullptr);
     if (clientSocket == -1) {
         cout << "Client socket failed" << endl;
+        return clientSocket;
     }
 
+    // Attach our SSL context to the socket
     SSL *ssl = SSL_new(ctx);
     SSL_set_fd(ssl, clientSocket);
 
@@ -110,25 +133,41 @@ int main() {
         char *errStr = ERR_error_string(ERR_get_error(), nullptr);
         cout << "SSL_accept failed with SSL error: " << sslError << endl;
         cout << "OpenSSL error: " << errStr << endl;
+        return sslAcceptCode;
     } else {
         cout << "negotiated SSL" << endl;
     }
 
     while (true) {
+
+        // Define buffer for incoming data
         char buffer[1024] = {0};
+
+        // Read the incoming data and save it to the buffer
         SSL_read(ssl, buffer, sizeof(buffer) - 1);
 
+        // If the buffer is empty then the client has closed the connection
+        // Therefore just exit the while loop
         if (strlen(buffer) <= 0) {
             cout << "Client seems to have just straight up left :(" << endl;
             break;
         }
 
+        // The buffer contains data
+        // Print the data the client sent
         cout << buffer << endl;
     }
 
+    // Deallocate the SSL objects
     SSL_free(ssl);
+
+    // Deallocate the SSL context
     SSL_CTX_free(ctx);
+
+    // Deallocate the SSL error strings
     ERR_free_strings();
+
+    // Close the network socket
     close(serverSocket);
 
     return 0;