Add test cases for DTLS_get_data_mtu()

  INCLUDE[bio_enc_test]=../include

  DEPEND[bio_enc_test]=../libcrypto

  IF[{- !$disabled{psk} -}]

    PROGRAMS_NO_INST=dtls_mtu_test

    SOURCE[dtls_mtu_test]=dtls_mtu_test.c ssltestlib.c

    INCLUDE[dtls_mtu_test]=.. ../include

    DEPEND[dtls_mtu_test]=../libcrypto ../libssl

  ENDIF

  IF[{- $disabled{shared} -}]

    PROGRAMS_NO_INST=wpackettest cipher_overhead_test

    SOURCE[wpackettest]=wpackettest.c testutil.c

/*

 * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stdio.h>

#include <string.h>

#include <openssl/dtls1.h>

#include <openssl/ssl.h>

#include <openssl/err.h>

#include "ssltestlib.h"

/* for SSL_USE_ETM() */

#include "../ssl/ssl_locl.h"

static int debug = 0;

static unsigned int clnt_psk_callback(SSL *ssl, const char *hint,

                                      char *ident, unsigned int max_ident_len,

                                      unsigned char *psk,

                                      unsigned int max_psk_len)

{

    snprintf(ident, max_ident_len, "psk");

    if (max_psk_len > 20)

        max_psk_len = 20;

    memset(psk, 0x5a, max_psk_len);

    return max_psk_len;

}

static unsigned int srvr_psk_callback(SSL *ssl, const char *identity,

                                      unsigned char *psk,

                                      unsigned int max_psk_len)

{

    if (max_psk_len > 20)

        max_psk_len = 20;

    memset(psk, 0x5a, max_psk_len);

    return max_psk_len;

}

static int mtu_test(SSL_CTX *ctx, const char *cs, int no_etm)

{

    SSL *srvr_ssl = NULL, *clnt_ssl = NULL;

    BIO *sc_bio = NULL;

    int i;

    size_t s;

    size_t mtus[30];

    unsigned char buf[600];

    int rv = 0;

    memset(buf, 0x5a, sizeof(buf));

    if (create_ssl_objects(ctx, ctx, &srvr_ssl, &clnt_ssl, NULL, NULL) != 1)

        goto out;

    if (no_etm)

        SSL_set_options(srvr_ssl, SSL_OP_NO_ENCRYPT_THEN_MAC);

    if (SSL_set_cipher_list(srvr_ssl, cs) != 1 ||

        SSL_set_cipher_list(clnt_ssl, cs) != 1) {

        ERR_print_errors_fp(stdout);

        goto out;

    }

    sc_bio = SSL_get_rbio(srvr_ssl);

    if (create_ssl_connection(clnt_ssl, srvr_ssl) != 1)

        goto out;

    if (debug)

        printf("Channel established\n");

    /* For record MTU values between 500 and 539, call DTLS_get_data_mtu()

     * to query the payload MTU which will fit. */

    for (i = 0; i < 30; i++) {

        SSL_set_mtu(clnt_ssl, 500 + i);

        mtus[i] = DTLS_get_data_mtu(clnt_ssl);

        if (debug)

            printf("%s%s payload MTU for record mtu %d = %"OSSLzu"\n",

                   cs, no_etm ? "-noEtM":"", 500 + i, mtus[i]);

        if (mtus[i] == 0) {

            fprintf(stderr,

                    "payload MTU failed with record MTU %d for %s\n",

                    500 + i, cs);

            goto out;

        }

    }

    /* Now get out of the way */

    SSL_set_mtu(clnt_ssl, 1000);

    /* Now for all values in the range of payload MTUs, send

     * a payload of that size and see what actual record size

     * we end up with. */

    for (s = mtus[0]; s <= mtus[29]; s++) {

        size_t reclen;

        if (SSL_write(clnt_ssl, buf, s) != (int)s) {

            ERR_print_errors_fp(stdout);

            goto out;

        }

        reclen = BIO_read(sc_bio, buf, sizeof(buf));

        if (debug)

            printf("record %"OSSLzu" for payload %"OSSLzu"\n", reclen, s);

        for (i = 0; i < 30; i++) {

            /* DTLS_get_data_mtu() with record MTU 500+i returned mtus[i] ... */

            if (s <= mtus[i] && reclen > (size_t)(500 + i)) {

                /* We sent a packet smaller than or equal to mtus[j] and

                 * that made a record *larger* than the record MTU 500+j! */

                fprintf(stderr,

                        "%s: Payload MTU %"OSSLzu" reported for record MTU %d\n"

                        "but sending a payload of %"OSSLzu" made a record of %"OSSLzu"(too large)\n",

                        cs, mtus[i], 500 + i, s, reclen);

                goto out;

            }

            if (s > mtus[i] && reclen <= (size_t)(500 + i)) {

                /* We sent a *larger* packet than mtus[i] and that *still*

                 * fits within the record MTU 500+i, so DTLS_get_data_mtu()

                 * was overly pessimistic. */

                fprintf(stderr,

                        "%s: Payload MTU %"OSSLzu" reported for record MTU %d\n"

                        "but sending a payload of %"OSSLzu" made a record of %"OSSLzu" (too small)\n",

                        cs, mtus[i], 500 + i, s, reclen);

                goto out;

            }

        }

    }

    rv = 1;

    if (SSL_USE_ETM(clnt_ssl))

        rv = 2;

 out:

    SSL_free(clnt_ssl);

    SSL_free(srvr_ssl);

    return rv;

}

int main(void)

{

    SSL_CTX *ctx = SSL_CTX_new(DTLS_method());

    STACK_OF(SSL_CIPHER) *ciphers;

    int i, rv = 0;

    SSL_CTX_set_psk_server_callback(ctx, srvr_psk_callback);

    SSL_CTX_set_psk_client_callback(ctx, clnt_psk_callback);

    SSL_CTX_set_security_level(ctx, 0);

    /* We only care about iterating over each enc/mac; we don't

     * want to repeat the test for each auth/kx variant.

     * So keep life simple and only do (non-DH) PSK. */

    if (!SSL_CTX_set_cipher_list(ctx, "PSK")) {

        fprintf(stderr, "Failed to set PSK cipher list\n");

        goto out;

    }

    ciphers = SSL_CTX_get_ciphers(ctx);

    for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {

        const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(ciphers, i);

        const char *cipher_name = SSL_CIPHER_get_name(cipher);

        /* As noted above, only one test for each enc/mac variant. */

        if (strncmp(cipher_name, "PSK-", 4))

            continue;

        rv = mtu_test(ctx, cipher_name, 0);

        if (!rv)

            break;

        printf("DTLS MTU test OK for %s\n", cipher_name);

        if (rv == 1)

            continue;

        /* mtu_test() returns 2 if it used Encrypt-then-MAC */

        rv = mtu_test(ctx, cipher_name, 1);

        if (!rv)

            break;

        printf("DTLS MTU test OK for %s without Encrypt-then-MAC\n", cipher_name);

    }

 out:

    SSL_CTX_free(ctx);

    return !rv;

}

#! /usr/bin/env perl

# Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.

#

# Licensed under the OpenSSL license (the "License").  You may not use

# this file except in compliance with the License.  You can obtain a copy

# in the file LICENSE in the source distribution or at

# https://www.openssl.org/source/license.html

use OpenSSL::Test;

use OpenSSL::Test::Utils;

my $test_name = "test_dtls_mtu";

setup($test_name);

plan skip_all => "$test_name needs DTLS and PSK support enabled"

    if disabled("dtls1_2") || disabled("psk");

plan tests => 1;

ok(run(test(["dtls_mtu_test"])), "running dtls_mtu_test");