/* wolfSSL-DTLS-PSK-Server.cs * * Copyright (C) 2006-2020 wolfSSL Inc. * * This file is part of wolfSSL. * * 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 02110-1335, USA */ using System; using System.Runtime.InteropServices; using System.Text; using System.Threading; using System.IO; using System.Net; using System.Net.Sockets; using wolfSSL.CSharp; public class wolfSSL_DTLS_PSK_Server { /// /// Example of a PSK function call back /// /// pointer to ssl structure /// identity of client connecting /// buffer to hold key /// max key size /// size of key set public static uint my_psk_server_cb(IntPtr ssl, string identity, IntPtr key, uint max_key) { /* perform a check on the identity sent across * log function must be set for print out of logging information */ wolfssl.log(wolfssl.INFO_LOG, "PSK Client Identity = " + identity); /* Use desired key, note must be a key smaller than max key size parameter Replace this with desired key. Is trivial one for testing */ if (max_key < 4) return 0; byte[] tmp = { 26, 43, 60, 77 }; Marshal.Copy(tmp, 0, key, 4); return (uint)4; } private static void clean(IntPtr ssl, IntPtr ctx) { wolfssl.free(ssl); wolfssl.CTX_free(ctx); wolfssl.Cleanup(); } public static void Main(string[] args) { IntPtr ctx; IntPtr ssl; /* These paths should be changed according to use */ string fileCert = @"server-cert.pem"; string fileKey = @"server-key.pem"; StringBuilder dhparam = new StringBuilder("dh2048.pem"); wolfssl.psk_delegate psk_cb = new wolfssl.psk_delegate(my_psk_server_cb); StringBuilder buff = new StringBuilder(1024); StringBuilder reply = new StringBuilder("Hello, this is the wolfSSL C# wrapper"); wolfssl.Init(); Console.WriteLine("Calling ctx Init from wolfSSL"); ctx = wolfssl.CTX_dtls_new(wolfssl.useDTLSv1_2_server()); if (ctx == IntPtr.Zero) { Console.WriteLine("Error creating ctx structure"); return; } Console.WriteLine("Finished init of ctx .... now load in cert and key"); if (!File.Exists(fileCert) || !File.Exists(fileKey)) { Console.WriteLine("Could not find cert or key file"); wolfssl.CTX_free(ctx); return; } if (wolfssl.CTX_use_certificate_file(ctx, fileCert, wolfssl.SSL_FILETYPE_PEM) != wolfssl.SUCCESS) { Console.WriteLine("Error setting cert file"); wolfssl.CTX_free(ctx); return; } if (wolfssl.CTX_use_PrivateKey_file(ctx, fileKey, wolfssl.SSL_FILETYPE_PEM) != wolfssl.SUCCESS) { Console.WriteLine("Error setting key file"); wolfssl.CTX_free(ctx); return; } /* Test psk use with DHE */ StringBuilder hint = new StringBuilder("cyassl server"); if (wolfssl.CTX_use_psk_identity_hint(ctx, hint) != wolfssl.SUCCESS) { Console.WriteLine("Error setting hint"); wolfssl.CTX_free(ctx); return; } wolfssl.CTX_set_psk_server_callback(ctx, psk_cb); short minDhKey = 128; wolfssl.CTX_SetMinDhKey_Sz(ctx, minDhKey); Console.Write("Setting cipher suite to "); StringBuilder set_cipher = new StringBuilder("DHE-PSK-AES128-CBC-SHA256"); Console.WriteLine(set_cipher); if (wolfssl.CTX_set_cipher_list(ctx, set_cipher) != wolfssl.SUCCESS) { Console.WriteLine("Failed to set cipher suite"); wolfssl.CTX_free(ctx); return; } IPAddress ip = IPAddress.Parse("0.0.0.0"); UdpClient udp = new UdpClient(11111); IPEndPoint ep = new IPEndPoint(ip, 11111); Console.WriteLine("Started UDP and waiting for a connection"); ssl = wolfssl.new_ssl(ctx); if (ssl == IntPtr.Zero) { Console.WriteLine("Error creating ssl object"); udp.Close(); wolfssl.CTX_free(ctx); return; } if (wolfssl.SetTmpDH_file(ssl, dhparam, wolfssl.SSL_FILETYPE_PEM) != wolfssl.SUCCESS) { Console.WriteLine("Error in setting dhparam"); Console.WriteLine(wolfssl.get_error(ssl)); udp.Close(); clean(ssl, ctx); return; } if (wolfssl.set_dtls_fd(ssl, udp, ep) != wolfssl.SUCCESS) { Console.WriteLine(wolfssl.get_error(ssl)); udp.Close(); clean(ssl, ctx); return; } if (wolfssl.accept(ssl) != wolfssl.SUCCESS) { Console.WriteLine(wolfssl.get_error(ssl)); udp.Close(); clean(ssl, ctx); return; } /* print out results of TLS/SSL accept */ Console.WriteLine("SSL version is " + wolfssl.get_version(ssl)); Console.WriteLine("SSL cipher suite is " + wolfssl.get_current_cipher(ssl)); /* get connection information and print ip - port */ wolfssl.DTLS_con con = wolfssl.get_dtls_fd(ssl); Console.Write("Connected to ip "); Console.Write(con.ep.Address.ToString()); Console.Write(" on port "); Console.WriteLine(con.ep.Port.ToString()); /* read information sent and send a reply */ if (wolfssl.read(ssl, buff, 1023) < 0) { Console.WriteLine("Error reading message"); Console.WriteLine(wolfssl.get_error(ssl)); udp.Close(); clean(ssl, ctx); return; } Console.WriteLine(buff); if (wolfssl.write(ssl, reply, reply.Length) != reply.Length) { Console.WriteLine("Error writing message"); Console.WriteLine(wolfssl.get_error(ssl)); udp.Close(); clean(ssl, ctx); return; } Console.WriteLine("At the end freeing stuff"); wolfssl.shutdown(ssl); udp.Close(); clean(ssl, ctx); } }