testssl

testssl.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <openssl/ssl.h>
#include <openssl/err.h>

int main() {
    SSL_CTX *ctx;
    SSL *ssl;
    int server_fd, client_fd;

    // Initialize OpenSSL
    SSL_library_init();
    SSL_load_error_strings();
    ctx = SSL_CTX_new(TLSv1_2_server_method());

    // Load the self-signed certificate and private key
    SSL_CTX_use_certificate_file(ctx, "/tmp/public.pem", SSL_FILETYPE_PEM);
    SSL_CTX_use_PrivateKey_file(ctx, "/tmp/private.pem", SSL_FILETYPE_PEM);

    // Create a socket
    server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd == -1) {
        perror("Failed to create socket");
        exit(EXIT_FAILURE);
    }

    // Allow rebind to avoid "Address already in use" error
    int reuseaddr = 1;
    if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof(reuseaddr)) == -1) {
        perror("Failed to set socket options");
        exit(EXIT_FAILURE);
    }

    // Bind to port 443
    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(443);
    server_addr.sin_addr.s_addr = INADDR_ANY;

    if (bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) == -1) {
        perror("Failed to bind");
        exit(EXIT_FAILURE);
    }

    // Listen for incoming connections
    if (listen(server_fd, 10) == -1) {
        perror("Failed to listen");
        exit(EXIT_FAILURE);
    }

    printf("Server listening on port 443...\n");

    while (1) {
        struct sockaddr_in client_addr;
        socklen_t client_len = sizeof(client_addr);

        // Accept a client connection
        client_fd = accept(server_fd, (struct sockaddr *)&client_addr, &client_len);
        if (client_fd == -1) {
            perror("Failed to accept client connection");
            continue;
        }

        // Create an SSL object and set the socket
        ssl = SSL_new(ctx);
        SSL_set_fd(ssl, client_fd);

        // Perform SSL handshake
        if (SSL_accept(ssl) != 1) {
            ERR_print_errors_fp(stderr);
            close(client_fd);
            SSL_free(ssl);
            continue;
        }

        // Send an HTTP response
        const char *response = "HTTP/1.1 200 OK\r\nContent-Length: 12\r\n\r\nHello, World!";
        SSL_write(ssl, response, strlen(response));

        // Shutdown SSL and close the connection
        SSL_shutdown(ssl);
        SSL_free(ssl);
        close(client_fd);
    }

    // Clean up
    close(server_fd);
    SSL_CTX_free(ctx);
    return 0;
}