/* server-tls-posthsauth.c
 *
 * Copyright (C) 2006-2024 wolfSSL Inc.
 *
 * This file is part of wolfSSL. (formerly known as CyaSSL)
 *
 * wolfSSL is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * wolfSSL is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */

/* the usual suspects */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

/* socket includes */
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <unistd.h>

#define HAVE_SIGNAL
#ifdef HAVE_SIGNAL
#include <signal.h>        /* signal */
#endif

/* wolfSSL */
#ifndef WOLFSSL_USER_SETTINGS
    #include <wolfssl/options.h>
#endif
#include <wolfssl/ssl.h>
#include <wolfssl/wolfio.h>
#include <wolfssl/wolfcrypt/error-crypt.h>

#if defined(WOLFSSL_POST_HANDSHAKE_AUTH) && defined(WOLFSSL_TLS13)
#define DEFAULT_PORT 11111

#define CERT_FILE "../certs/server-cert.pem"
#define KEY_FILE  "../certs/server-key.pem"
#define CA_FILE   "../certs/client-cert.pem"


static int mSockfd = SOCKET_INVALID;
static int mConnd = SOCKET_INVALID;
static int mShutdown = 0;

#ifdef HAVE_SIGNAL
static void sig_handler(const int sig)
{
    fprintf(stderr, "SIGINT handled = %d.\n", sig);

    mShutdown = 1;
    if (mConnd != SOCKET_INVALID) {
        close(mConnd);           /* Close the connection to the client   */
        mConnd = SOCKET_INVALID;
    }
    if (mSockfd != SOCKET_INVALID) {
        close(mSockfd);          /* Close the socket listening for clients   */
        mSockfd = SOCKET_INVALID;
    }
}
#endif

int main(int argc, char** argv)
{
    int ret = 0;
    struct sockaddr_in servAddr;
    struct sockaddr_in clientAddr;
    socklen_t          size = sizeof(clientAddr);
    char               buff[256];
    size_t             len;
    const char*        reply = "I hear ya fa shizzle!\n";
    int                on;

    /* declare wolfSSL objects */
    WOLFSSL_CTX* ctx = NULL;
    WOLFSSL*     ssl = NULL;

#ifdef HAVE_SIGNAL
    signal(SIGINT, sig_handler);
#endif

    /* Initialize the server address struct with zeros */
    memset(&servAddr, 0, sizeof(servAddr));

    /* Fill in the server address */
    servAddr.sin_family      = AF_INET;             /* using IPv4      */
    servAddr.sin_port        = htons(DEFAULT_PORT); /* on DEFAULT_PORT */
    servAddr.sin_addr.s_addr = INADDR_ANY;          /* from anywhere   */


    /* Create a socket that uses an internet IPv4 address,
     * Sets the socket to be stream based (TCP),
     * 0 means choose the default protocol. */
    if ((mSockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        fprintf(stderr, "ERROR: failed to create the socket\n");
        goto exit;
    }

    /* make sure server is setup for reuse addr/port */
    on = 1;
    setsockopt(mSockfd, SOL_SOCKET, SO_REUSEADDR,
            (char*)&on, (socklen_t)sizeof(on));
#ifdef SO_REUSEPORT
    setsockopt(mSockfd, SOL_SOCKET, SO_REUSEPORT,
               (char*)&on, (socklen_t)sizeof(on));
#endif

    /* Bind the server socket to our port */
    if (bind(mSockfd, (struct sockaddr*)&servAddr, sizeof(servAddr)) == -1) {
        fprintf(stderr, "ERROR: failed to bind\n");
        goto exit;
    }

    /* Listen for a new connection, allow 5 pending connections */
    if (listen(mSockfd, 5) == -1) {
        fprintf(stderr, "ERROR: failed to listen\n");
        goto exit;
    }

    /*---------------------------------*/
    /* Start of wolfSSL initialization and configuration */
    /*---------------------------------*/
#if 0
    wolfSSL_Debugging_ON();
#endif

    /* Initialize wolfSSL */
    if ((ret = wolfSSL_Init()) != WOLFSSL_SUCCESS) {
        fprintf(stderr, "ERROR: Failed to initialize the library\n");
        goto exit;
    }

    /* Create and initialize WOLFSSL_CTX */
    if ((ctx = wolfSSL_CTX_new(wolfTLSv1_3_server_method())) == NULL) {
        fprintf(stderr, "ERROR: failed to create WOLFSSL_CTX\n");
        ret = -1;
        goto exit;
    }

    /* POSTHSAUTH: No verification during handshake.  Will be doing it post
     *             handshake. */
    wolfSSL_CTX_set_verify(ctx, SSL_VERIFY_NONE, NULL);

    /* Load server certificates into WOLFSSL_CTX */
    if ((ret = wolfSSL_CTX_use_certificate_file(ctx, CERT_FILE,
                                    WOLFSSL_FILETYPE_PEM)) != WOLFSSL_SUCCESS) {
        fprintf(stderr, "ERROR: failed to load %s, please check the file.\n",
                CERT_FILE);
        goto exit;
    }

    /* Load server key into WOLFSSL_CTX */
    if ((ret = wolfSSL_CTX_use_PrivateKey_file(ctx, KEY_FILE,
                                    WOLFSSL_FILETYPE_PEM)) != WOLFSSL_SUCCESS) {
        fprintf(stderr, "ERROR: failed to load %s, please check the file.\n",
                KEY_FILE);
        goto exit;
    }

    /* Load client certificate as "trusted" into WOLFSSL_CTX */
    if ((ret = wolfSSL_CTX_load_verify_locations(ctx, CA_FILE, NULL))
         != WOLFSSL_SUCCESS) {
        fprintf(stderr, "ERROR: failed to load %s, please check the file.\n",
                CA_FILE);
        goto exit;
    }

    /* Continue to accept clients until mShutdown is issued */
    while (!mShutdown) {
        printf("Waiting for a connection...\n");

        /* Accept client connections */
        if ((mConnd = accept(mSockfd, (struct sockaddr*)&clientAddr, &size))
            == -1) {
            fprintf(stderr, "ERROR: failed to accept the connection\n\n");
            ret = -1; goto exit;
        }

        /* Create a WOLFSSL object */
        if ((ssl = wolfSSL_new(ctx)) == NULL) {
            fprintf(stderr, "ERROR: failed to create WOLFSSL object\n");
            ret = -1; goto exit;
        }

        /* Attach wolfSSL to the socket */
        wolfSSL_set_fd(ssl, mConnd);

        /* Establish TLS connection */
        if ((ret = wolfSSL_accept(ssl)) != WOLFSSL_SUCCESS) {
            fprintf(stderr, "wolfSSL_accept error = %d\n",
                wolfSSL_get_error(ssl, ret));
            goto exit;
        }

        printf("Client connected successfully\n");

        /* Read the client data into our buff array */
        memset(buff, 0, sizeof(buff));
        if ((ret = wolfSSL_read(ssl, buff, sizeof(buff)-1)) < 0) {
            fprintf(stderr, "ERROR: failed to read\n");
            goto exit;
        }

        /* Print to stdout any data the client sends */
        printf("Client: %s\n", buff);

        /* Check for server shutdown command */
        if (strncmp(buff, "shutdown", 8) == 0) {
            printf("Shutdown command issued!\n");
            mShutdown = 1;
        }

        /* POSTHSAUTH: Require the client to send over their certificate; fail
         *             if we cannot verify the client. */
        wolfSSL_set_verify(ssl,
            WOLFSSL_VERIFY_PEER | WOLFSSL_VERIFY_FAIL_IF_NO_PEER_CERT, 0);

        /* POSTHSAUTH: Request the certficate and do the verification. */
        if (wolfSSL_request_certificate(ssl) != WOLFSSL_SUCCESS) {
            fprintf(stderr, "ERROR: Request for post-hs certificate failed\n");
            goto exit;
        }
        else {
            printf("Successfully requested post-hs certificate\n");
        }

        /* Write our reply into buff */
        memset(buff, 0, sizeof(buff));
        memcpy(buff, reply, strlen(reply));
        len = strnlen(buff, sizeof(buff));

        /* Reply back to the client */
        if ((ret = wolfSSL_write(ssl, buff, len)) != len) {
            fprintf(stderr, "ERROR: failed to write\n");
            goto exit;
        }

        /* POSTHSAUTH: Read second message into our buff array. This is now
         *             authenticated. */
        memset(buff, 0, sizeof(buff));
        if ((ret = wolfSSL_read(ssl, buff, sizeof(buff)-1)) < 0) {
            fprintf(stderr, "ERROR: failed to read\n");
            goto exit;
        }

        /* Print to stdout any data the client sends */
        printf("Client2: %s\n", buff);

        /* Cleanup after this connection */
        wolfSSL_shutdown(ssl);
        if (ssl) {
            wolfSSL_free(ssl);      /* Free the wolfSSL object              */
            ssl = NULL;
        }
        if (mConnd != SOCKET_INVALID) {
            close(mConnd);           /* Close the connection to the client   */
            mConnd = SOCKET_INVALID;
        }
    }

    printf("Shutdown complete\n");

exit:
    /* Cleanup and return */
    if (ssl)
        wolfSSL_free(ssl);      /* Free the wolfSSL object              */
    if (mConnd != SOCKET_INVALID) {
        close(mConnd);           /* Close the connection to the client   */
        mConnd = SOCKET_INVALID;
    }
    if (mSockfd != SOCKET_INVALID) {
        close(mSockfd);          /* Close the socket listening for clients   */
        mSockfd = SOCKET_INVALID;
    }
    if (ctx)
        wolfSSL_CTX_free(ctx);  /* Free the wolfSSL context object          */
    wolfSSL_Cleanup();          /* Cleanup the wolfSSL environment          */
    return ret;
}
#else
int main() {
    fprintf(stderr, "Please configure with --enable-postauth or compile with "
                    "WOLFSSL_POST_HANDSHAKE_AUTH defined. Do not disable "
                    "TLS 1.3.\n");
    return 0;
}
#endif /* WOLFSSL_POST_HANDSHAKE_AUTH && WOLFSSL_TLS13 */