[thirdparty/openssl.git] / ssl / d1_srvr.c

/* ssl/d1_srvr.c */
/*
 * DTLS implementation written by Nagendra Modadugu
 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
 */
/* ====================================================================
 * Copyright (c) 1999-2005 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include "ssl_locl.h"
#include <openssl/buffer.h>
#include <openssl/rand.h>
#include <openssl/objects.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
#include <openssl/md5.h>
#ifndef OPENSSL_NO_DH
# include <openssl/dh.h>
#endif

static SSL_METHOD *dtls1_get_server_method(int ver);
static int dtls1_send_hello_verify_request(SSL *s);

static SSL_METHOD *dtls1_get_server_method(int ver)
{
    if (ver == DTLS1_VERSION)
        return (DTLSv1_server_method());
    else
        return (NULL);
}

IMPLEMENT_dtls1_meth_func(DTLSv1_server_method,
                          dtls1_accept,
                          ssl_undefined_function, dtls1_get_server_method)

int dtls1_accept(SSL *s)
{
    BUF_MEM *buf;
    unsigned long l, Time = (unsigned long)time(NULL);
    void (*cb) (const SSL *ssl, int type, int val) = NULL;
    int ret = -1;
    int new_state, state, skip = 0;
    int listen;

    RAND_add(&Time, sizeof(Time), 0);
    ERR_clear_error();
    clear_sys_error();

    if (s->info_callback != NULL)
        cb = s->info_callback;
    else if (s->ctx->info_callback != NULL)
        cb = s->ctx->info_callback;

    listen = s->d1->listen;

    /* init things to blank */
    s->in_handshake++;
    if (!SSL_in_init(s) || SSL_in_before(s))
        SSL_clear(s);

    s->d1->listen = listen;

    if (s->cert == NULL) {
        SSLerr(SSL_F_DTLS1_ACCEPT, SSL_R_NO_CERTIFICATE_SET);
        return (-1);
    }

    for (;;) {
        state = s->state;

        switch (s->state) {
        case SSL_ST_RENEGOTIATE:
            s->new_session = 1;
            /* s->state=SSL_ST_ACCEPT; */

        case SSL_ST_BEFORE:
        case SSL_ST_ACCEPT:
        case SSL_ST_BEFORE | SSL_ST_ACCEPT:
        case SSL_ST_OK | SSL_ST_ACCEPT:

            s->server = 1;
            if (cb != NULL)
                cb(s, SSL_CB_HANDSHAKE_START, 1);

            if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
                SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
                return -1;
            }
            s->type = SSL_ST_ACCEPT;

            if (s->init_buf == NULL) {
                if ((buf = BUF_MEM_new()) == NULL) {
                    ret = -1;
                    goto end;
                }
                if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
                    ret = -1;
                    goto end;
                }
                s->init_buf = buf;
            }

            if (!ssl3_setup_buffers(s)) {
                ret = -1;
                goto end;
            }

            s->init_num = 0;

            if (s->state != SSL_ST_RENEGOTIATE) {
                /*
                 * Ok, we now need to push on a buffering BIO so that the
                 * output is sent in a way that TCP likes :-)
                 */
                if (!ssl_init_wbio_buffer(s, 1)) {
                    ret = -1;
                    goto end;
                }

                ssl3_init_finished_mac(s);
                s->state = SSL3_ST_SR_CLNT_HELLO_A;
                s->ctx->stats.sess_accept++;
            } else {
                /*
                 * s->state == SSL_ST_RENEGOTIATE, we will just send a
                 * HelloRequest
                 */
                s->ctx->stats.sess_accept_renegotiate++;
                s->state = SSL3_ST_SW_HELLO_REQ_A;
            }

            break;

        case SSL3_ST_SW_HELLO_REQ_A:
        case SSL3_ST_SW_HELLO_REQ_B:

            s->shutdown = 0;
            dtls1_clear_record_buffer(s);
            dtls1_start_timer(s);
            ret = dtls1_send_hello_request(s);
            if (ret <= 0)
                goto end;
            s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;
            s->state = SSL3_ST_SW_FLUSH;
            s->init_num = 0;

            ssl3_init_finished_mac(s);
            break;

        case SSL3_ST_SW_HELLO_REQ_C:
            s->state = SSL_ST_OK;
            break;

        case SSL3_ST_SR_CLNT_HELLO_A:
        case SSL3_ST_SR_CLNT_HELLO_B:
        case SSL3_ST_SR_CLNT_HELLO_C:

            s->shutdown = 0;
            ret = ssl3_get_client_hello(s);
            if (ret <= 0)
                goto end;
            dtls1_stop_timer(s);

            if (ret == 1 && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
                s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
            else
                s->state = SSL3_ST_SW_SRVR_HELLO_A;

            s->init_num = 0;

            /*
             * Reflect ClientHello sequence to remain stateless while
             * listening
             */
            if (listen) {
                memcpy(s->s3->write_sequence, s->s3->read_sequence,
                       sizeof(s->s3->write_sequence));
            }

            /* If we're just listening, stop here */
            if (listen && s->state == SSL3_ST_SW_SRVR_HELLO_A) {
                ret = 2;
                s->d1->listen = 0;
                /*
                 * Set expected sequence numbers to continue the handshake.
                 */
                s->d1->handshake_read_seq = 2;
                s->d1->handshake_write_seq = 1;
                s->d1->next_handshake_write_seq = 1;
                goto end;
            }

            break;

        case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A:
        case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B:

            ret = dtls1_send_hello_verify_request(s);
            if (ret <= 0)
                goto end;
            s->state = SSL3_ST_SW_FLUSH;
            s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;

            /* HelloVerifyRequests resets Finished MAC */
            if (s->client_version != DTLS1_BAD_VER)
                ssl3_init_finished_mac(s);
            break;

        case SSL3_ST_SW_SRVR_HELLO_A:
        case SSL3_ST_SW_SRVR_HELLO_B:
            s->new_session = 2;
            dtls1_start_timer(s);
            ret = dtls1_send_server_hello(s);
            if (ret <= 0)
                goto end;

#ifndef OPENSSL_NO_TLSEXT
            if (s->hit) {
                if (s->tlsext_ticket_expected)
                    s->state = SSL3_ST_SW_SESSION_TICKET_A;
                else
                    s->state = SSL3_ST_SW_CHANGE_A;
            }
#else
            if (s->hit)
                s->state = SSL3_ST_SW_CHANGE_A;
#endif
            else
                s->state = SSL3_ST_SW_CERT_A;
            s->init_num = 0;
            break;

        case SSL3_ST_SW_CERT_A:
        case SSL3_ST_SW_CERT_B:
            /* Check if it is anon DH */
            if (!(s->s3->tmp.new_cipher->algorithms & SSL_aNULL)) {
                dtls1_start_timer(s);
                ret = dtls1_send_server_certificate(s);
                if (ret <= 0)
                    goto end;
#ifndef OPENSSL_NO_TLSEXT
                if (s->tlsext_status_expected)
                    s->state = SSL3_ST_SW_CERT_STATUS_A;
                else
                    s->state = SSL3_ST_SW_KEY_EXCH_A;
            } else {
                skip = 1;
                s->state = SSL3_ST_SW_KEY_EXCH_A;
            }
#else
            } else
                skip = 1;

            s->state = SSL3_ST_SW_KEY_EXCH_A;
#endif
            s->init_num = 0;
            break;

        case SSL3_ST_SW_KEY_EXCH_A:
        case SSL3_ST_SW_KEY_EXCH_B:
            l = s->s3->tmp.new_cipher->algorithms;

            /*
             * clear this, it may get reset by send_server_key_exchange
             */
            s->s3->tmp.use_rsa_tmp = 0;

            /*
             * only send if a DH key exchange, fortezza or RSA but we have a
             * sign only certificate
             */
            if ((l & (SSL_DH | SSL_kFZA))
                || ((l & SSL_kRSA)
                    && (s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL
                        || (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher)
                            && EVP_PKEY_size(s->cert->pkeys
                                             [SSL_PKEY_RSA_ENC].privatekey) *
                            8 > SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher)
                        )
                    )
                )
                ) {
                dtls1_start_timer(s);
                ret = dtls1_send_server_key_exchange(s);
                if (ret <= 0)
                    goto end;
            } else
                skip = 1;

            s->state = SSL3_ST_SW_CERT_REQ_A;
            s->init_num = 0;
            break;

        case SSL3_ST_SW_CERT_REQ_A:
        case SSL3_ST_SW_CERT_REQ_B:
            if (                /* don't request cert unless asked for it: */
                   !(s->verify_mode & SSL_VERIFY_PEER) ||
                   /*
                    * if SSL_VERIFY_CLIENT_ONCE is set, don't request cert
                    * during re-negotiation:
                    */
                   ((s->session->peer != NULL) &&
                    (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)) ||
                   /*
                    * never request cert in anonymous ciphersuites (see
                    * section "Certificate request" in SSL 3 drafts and in
                    * RFC 2246):
                    */
                   ((s->s3->tmp.new_cipher->algorithms & SSL_aNULL) &&
                    /*
                     * ... except when the application insists on
                     * verification (against the specs, but s3_clnt.c accepts
                     * this for SSL 3)
                     */
                    !(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) ||
                   /*
                    * never request cert in Kerberos ciphersuites
                    */
                   (s->s3->tmp.new_cipher->algorithms & SSL_aKRB5)) {
                /* no cert request */
                skip = 1;
                s->s3->tmp.cert_request = 0;
                s->state = SSL3_ST_SW_SRVR_DONE_A;
            } else {
                s->s3->tmp.cert_request = 1;
                dtls1_start_timer(s);
                ret = dtls1_send_certificate_request(s);
                if (ret <= 0)
                    goto end;
#ifndef NETSCAPE_HANG_BUG
                s->state = SSL3_ST_SW_SRVR_DONE_A;
#else
                s->state = SSL3_ST_SW_FLUSH;
                s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
#endif
                s->init_num = 0;
            }
            break;

        case SSL3_ST_SW_SRVR_DONE_A:
        case SSL3_ST_SW_SRVR_DONE_B:
            dtls1_start_timer(s);
            ret = dtls1_send_server_done(s);
            if (ret <= 0)
                goto end;
            s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
            s->state = SSL3_ST_SW_FLUSH;
            s->init_num = 0;
            break;

        case SSL3_ST_SW_FLUSH:
            s->rwstate = SSL_WRITING;
            if (BIO_flush(s->wbio) <= 0) {
                ret = -1;
                goto end;
            }
            s->rwstate = SSL_NOTHING;
            s->state = s->s3->tmp.next_state;
            break;

        case SSL3_ST_SR_CERT_A:
        case SSL3_ST_SR_CERT_B:
            /* Check for second client hello (MS SGC) */
            ret = ssl3_check_client_hello(s);
            if (ret <= 0)
                goto end;
            if (ret == 2) {
                dtls1_stop_timer(s);
                s->state = SSL3_ST_SR_CLNT_HELLO_C;
            } else {
                if (s->s3->tmp.cert_request) {
                    ret = ssl3_get_client_certificate(s);
                    if (ret <= 0)
                        goto end;
                }
                s->init_num = 0;
                s->state = SSL3_ST_SR_KEY_EXCH_A;
            }
            break;

        case SSL3_ST_SR_KEY_EXCH_A:
        case SSL3_ST_SR_KEY_EXCH_B:
            ret = ssl3_get_client_key_exchange(s);
            if (ret <= 0)
                goto end;
            s->state = SSL3_ST_SR_CERT_VRFY_A;
            s->init_num = 0;

            /*
             * We need to get hashes here so if there is a client cert, it
             * can be verified
             */
            s->method->ssl3_enc->cert_verify_mac(s,
                                                 &(s->s3->finish_dgst1),
                                                 &(s->s3->
                                                   tmp.cert_verify_md[0]));
            s->method->ssl3_enc->cert_verify_mac(s, &(s->s3->finish_dgst2),
                                                 &(s->s3->
                                                   tmp.cert_verify_md
                                                   [MD5_DIGEST_LENGTH]));

            break;

        case SSL3_ST_SR_CERT_VRFY_A:
        case SSL3_ST_SR_CERT_VRFY_B:

            s->d1->change_cipher_spec_ok = 1;
            /* we should decide if we expected this one */
            ret = ssl3_get_cert_verify(s);
            if (ret <= 0)
                goto end;

            s->state = SSL3_ST_SR_FINISHED_A;
            s->init_num = 0;
            break;

        case SSL3_ST_SR_FINISHED_A:
        case SSL3_ST_SR_FINISHED_B:
            s->d1->change_cipher_spec_ok = 1;
            ret = ssl3_get_finished(s, SSL3_ST_SR_FINISHED_A,
                                    SSL3_ST_SR_FINISHED_B);
            if (ret <= 0)
                goto end;
            dtls1_stop_timer(s);
            if (s->hit)
                s->state = SSL_ST_OK;
#ifndef OPENSSL_NO_TLSEXT
            else if (s->tlsext_ticket_expected)
                s->state = SSL3_ST_SW_SESSION_TICKET_A;
#endif
            else
                s->state = SSL3_ST_SW_CHANGE_A;
            s->init_num = 0;
            break;

#ifndef OPENSSL_NO_TLSEXT
        case SSL3_ST_SW_SESSION_TICKET_A:
        case SSL3_ST_SW_SESSION_TICKET_B:
            ret = dtls1_send_newsession_ticket(s);
            if (ret <= 0)
                goto end;
            s->state = SSL3_ST_SW_CHANGE_A;
            s->init_num = 0;
            break;

        case SSL3_ST_SW_CERT_STATUS_A:
        case SSL3_ST_SW_CERT_STATUS_B:
            ret = ssl3_send_cert_status(s);
            if (ret <= 0)
                goto end;
            s->state = SSL3_ST_SW_KEY_EXCH_A;
            s->init_num = 0;
            break;

#endif

        case SSL3_ST_SW_CHANGE_A:
        case SSL3_ST_SW_CHANGE_B:

            s->session->cipher = s->s3->tmp.new_cipher;
            if (!s->method->ssl3_enc->setup_key_block(s)) {
                ret = -1;
                goto end;
            }

            ret = dtls1_send_change_cipher_spec(s,
                                                SSL3_ST_SW_CHANGE_A,
                                                SSL3_ST_SW_CHANGE_B);

            if (ret <= 0)
                goto end;
            s->state = SSL3_ST_SW_FINISHED_A;
            s->init_num = 0;

            if (!s->method->ssl3_enc->change_cipher_state(s,
                                                          SSL3_CHANGE_CIPHER_SERVER_WRITE))
            {
                ret = -1;
                goto end;
            }

            dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
            break;

        case SSL3_ST_SW_FINISHED_A:
        case SSL3_ST_SW_FINISHED_B:
            ret = dtls1_send_finished(s,
                                      SSL3_ST_SW_FINISHED_A,
                                      SSL3_ST_SW_FINISHED_B,
                                      s->method->
                                      ssl3_enc->server_finished_label,
                                      s->method->
                                      ssl3_enc->server_finished_label_len);
            if (ret <= 0)
                goto end;
            s->state = SSL3_ST_SW_FLUSH;
            if (s->hit)
                s->s3->tmp.next_state = SSL3_ST_SR_FINISHED_A;
            else
                s->s3->tmp.next_state = SSL_ST_OK;
            s->init_num = 0;
            break;

        case SSL_ST_OK:
            /* clean a few things up */
            ssl3_cleanup_key_block(s);

#if 0
            BUF_MEM_free(s->init_buf);
            s->init_buf = NULL;
#endif

            /* remove buffering on output */
            ssl_free_wbio_buffer(s);

            s->init_num = 0;

            if (s->new_session == 2) { /* skipped if we just sent a
                                        * HelloRequest */
                /*
                 * actually not necessarily a 'new' session unless
                 * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION is set
                 */

                s->new_session = 0;

                ssl_update_cache(s, SSL_SESS_CACHE_SERVER);

                s->ctx->stats.sess_accept_good++;
                /* s->server=1; */
                s->handshake_func = dtls1_accept;

                if (cb != NULL)
                    cb(s, SSL_CB_HANDSHAKE_DONE, 1);
            }

            ret = 1;

            /* done handshaking, next message is client hello */
            s->d1->handshake_read_seq = 0;
            /* next message is server hello */
            s->d1->handshake_write_seq = 0;
            s->d1->next_handshake_write_seq = 0;
            goto end;
            /* break; */

        default:
            SSLerr(SSL_F_DTLS1_ACCEPT, SSL_R_UNKNOWN_STATE);
            ret = -1;
            goto end;
            /* break; */
        }

        if (!s->s3->tmp.reuse_message && !skip) {
            if (s->debug) {
                if ((ret = BIO_flush(s->wbio)) <= 0)
                    goto end;
            }

            if ((cb != NULL) && (s->state != state)) {
                new_state = s->state;
                s->state = state;
                cb(s, SSL_CB_ACCEPT_LOOP, 1);
                s->state = new_state;
            }
        }
        skip = 0;
    }
 end:
    /* BIO_flush(s->wbio); */

    s->in_handshake--;
    if (cb != NULL)
        cb(s, SSL_CB_ACCEPT_EXIT, ret);
    return (ret);
}

int dtls1_send_hello_request(SSL *s)
{
    unsigned char *p;

    if (s->state == SSL3_ST_SW_HELLO_REQ_A) {
        p = (unsigned char *)s->init_buf->data;
        p = dtls1_set_message_header(s, p, SSL3_MT_HELLO_REQUEST, 0, 0, 0);

        s->state = SSL3_ST_SW_HELLO_REQ_B;
        /* number of bytes to write */
        s->init_num = DTLS1_HM_HEADER_LENGTH;
        s->init_off = 0;

        /*
         * no need to buffer this message, since there are no retransmit
         * requests for it
         */
    }

    /* SSL3_ST_SW_HELLO_REQ_B */
    return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
}

int dtls1_send_hello_verify_request(SSL *s)
{
    unsigned int msg_len;
    unsigned char *msg, *buf, *p;

    if (s->state == DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A) {
        buf = (unsigned char *)s->init_buf->data;

        msg = p = &(buf[DTLS1_HM_HEADER_LENGTH]);
        if (s->client_version == DTLS1_BAD_VER)
            *(p++) = DTLS1_BAD_VER >> 8, *(p++) = DTLS1_BAD_VER & 0xff;
        else
            *(p++) = s->version >> 8, *(p++) = s->version & 0xFF;

        if (s->ctx->app_gen_cookie_cb == NULL ||
            s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
                                      &(s->d1->cookie_len)) == 0) {
            SSLerr(SSL_F_DTLS1_SEND_HELLO_VERIFY_REQUEST,
                   ERR_R_INTERNAL_ERROR);
            return 0;
        }

        *(p++) = (unsigned char)s->d1->cookie_len;
        memcpy(p, s->d1->cookie, s->d1->cookie_len);
        p += s->d1->cookie_len;
        msg_len = p - msg;

        dtls1_set_message_header(s, buf,
                                 DTLS1_MT_HELLO_VERIFY_REQUEST, msg_len, 0,
                                 msg_len);

        s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B;
        /* number of bytes to write */
        s->init_num = p - buf;
        s->init_off = 0;
    }

    /* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
    return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
}

int dtls1_send_server_hello(SSL *s)
{
    unsigned char *buf;
    unsigned char *p, *d;
    int i;
    unsigned int sl;
    unsigned long l, Time;

    if (s->state == SSL3_ST_SW_SRVR_HELLO_A) {
        buf = (unsigned char *)s->init_buf->data;
        p = s->s3->server_random;
        Time = (unsigned long)time(NULL); /* Time */
        l2n(Time, p);
        RAND_pseudo_bytes(p, SSL3_RANDOM_SIZE - 4);
        /* Do the message type and length last */
        d = p = &(buf[DTLS1_HM_HEADER_LENGTH]);

        if (s->client_version == DTLS1_BAD_VER)
            *(p++) = DTLS1_BAD_VER >> 8, *(p++) = DTLS1_BAD_VER & 0xff;
        else
            *(p++) = s->version >> 8, *(p++) = s->version & 0xff;

        /* Random stuff */
        memcpy(p, s->s3->server_random, SSL3_RANDOM_SIZE);
        p += SSL3_RANDOM_SIZE;

        /*
         * now in theory we have 3 options to sending back the session id.
         * If it is a re-use, we send back the old session-id, if it is a new
         * session, we send back the new session-id or we send back a 0
         * length session-id if we want it to be single use. Currently I will
         * not implement the '0' length session-id 12-Jan-98 - I'll now
         * support the '0' length stuff.
         */
        if (!(s->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER))
            s->session->session_id_length = 0;

        sl = s->session->session_id_length;
        if (sl > sizeof s->session->session_id) {
            SSLerr(SSL_F_DTLS1_SEND_SERVER_HELLO, ERR_R_INTERNAL_ERROR);
            return -1;
        }
        *(p++) = sl;
        memcpy(p, s->session->session_id, sl);
        p += sl;

        /* put the cipher */
        if (s->s3->tmp.new_cipher == NULL)
            return -1;
        i = ssl3_put_cipher_by_char(s->s3->tmp.new_cipher, p);
        p += i;

        /* put the compression method */
#ifdef OPENSSL_NO_COMP
        *(p++) = 0;
#else
        if (s->s3->tmp.new_compression == NULL)
            *(p++) = 0;
        else
            *(p++) = s->s3->tmp.new_compression->id;
#endif

#ifndef OPENSSL_NO_TLSEXT
        if ((p =
             ssl_add_serverhello_tlsext(s, p,
                                        buf + SSL3_RT_MAX_PLAIN_LENGTH)) ==
            NULL) {
            SSLerr(SSL_F_DTLS1_SEND_SERVER_HELLO, ERR_R_INTERNAL_ERROR);
            return -1;
        }
#endif

        /* do the header */
        l = (p - d);
        d = buf;

        d = dtls1_set_message_header(s, d, SSL3_MT_SERVER_HELLO, l, 0, l);

        s->state = SSL3_ST_SW_SRVR_HELLO_B;
        /* number of bytes to write */
        s->init_num = p - buf;
        s->init_off = 0;

        /* buffer the message to handle re-xmits */
        dtls1_buffer_message(s, 0);
    }

    /* SSL3_ST_SW_SRVR_HELLO_B */
    return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
}

int dtls1_send_server_done(SSL *s)
{
    unsigned char *p;

    if (s->state == SSL3_ST_SW_SRVR_DONE_A) {
        p = (unsigned char *)s->init_buf->data;

        /* do the header */
        p = dtls1_set_message_header(s, p, SSL3_MT_SERVER_DONE, 0, 0, 0);

        s->state = SSL3_ST_SW_SRVR_DONE_B;
        /* number of bytes to write */
        s->init_num = DTLS1_HM_HEADER_LENGTH;
        s->init_off = 0;

        /* buffer the message to handle re-xmits */
        dtls1_buffer_message(s, 0);
    }

    /* SSL3_ST_SW_SRVR_DONE_B */
    return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
}

int dtls1_send_server_key_exchange(SSL *s)
{
#ifndef OPENSSL_NO_RSA
    unsigned char *q;
    int j, num;
    RSA *rsa;
    unsigned char md_buf[MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH];
    unsigned int u;
#endif
#ifndef OPENSSL_NO_DH
    DH *dh = NULL, *dhp;
#endif
    EVP_PKEY *pkey;
    unsigned char *p, *d;
    int al, i;
    unsigned long type;
    int n;
    CERT *cert;
    BIGNUM *r[4];
    int nr[4], kn;
    BUF_MEM *buf;
    EVP_MD_CTX md_ctx;

    EVP_MD_CTX_init(&md_ctx);
    if (s->state == SSL3_ST_SW_KEY_EXCH_A) {
        type = s->s3->tmp.new_cipher->algorithms & SSL_MKEY_MASK;
        cert = s->cert;

        buf = s->init_buf;

        r[0] = r[1] = r[2] = r[3] = NULL;
        n = 0;
#ifndef OPENSSL_NO_RSA
        if (type & SSL_kRSA) {
            rsa = cert->rsa_tmp;
            if ((rsa == NULL) && (s->cert->rsa_tmp_cb != NULL)) {
                rsa = s->cert->rsa_tmp_cb(s,
                                          SSL_C_IS_EXPORT(s->s3->
                                                          tmp.new_cipher),
                                          SSL_C_EXPORT_PKEYLENGTH(s->s3->
                                                                  tmp.new_cipher));
                if (rsa == NULL) {
                    al = SSL_AD_HANDSHAKE_FAILURE;
                    SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,
                           SSL_R_ERROR_GENERATING_TMP_RSA_KEY);
                    goto f_err;
                }
                RSA_up_ref(rsa);
                cert->rsa_tmp = rsa;
            }
            if (rsa == NULL) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_MISSING_TMP_RSA_KEY);
                goto f_err;
            }
            r[0] = rsa->n;
            r[1] = rsa->e;
            s->s3->tmp.use_rsa_tmp = 1;
        } else
#endif
#ifndef OPENSSL_NO_DH
        if (type & SSL_kEDH) {
            dhp = cert->dh_tmp;
            if ((dhp == NULL) && (s->cert->dh_tmp_cb != NULL))
                dhp = s->cert->dh_tmp_cb(s,
                                         SSL_C_IS_EXPORT(s->s3->
                                                         tmp.new_cipher),
                                         SSL_C_EXPORT_PKEYLENGTH(s->s3->
                                                                 tmp.new_cipher));
            if (dhp == NULL) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_MISSING_TMP_DH_KEY);
                goto f_err;
            }

            if (s->s3->tmp.dh != NULL) {
                DH_free(dh);
                SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,
                       ERR_R_INTERNAL_ERROR);
                goto err;
            }

            if ((dh = DHparams_dup(dhp)) == NULL) {
                SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE, ERR_R_DH_LIB);
                goto err;
            }

            s->s3->tmp.dh = dh;
            if ((dhp->pub_key == NULL ||
                 dhp->priv_key == NULL ||
                 (s->options & SSL_OP_SINGLE_DH_USE))) {
                if (!DH_generate_key(dh)) {
                    SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,
                           ERR_R_DH_LIB);
                    goto err;
                }
            } else {
                dh->pub_key = BN_dup(dhp->pub_key);
                dh->priv_key = BN_dup(dhp->priv_key);
                if ((dh->pub_key == NULL) || (dh->priv_key == NULL)) {
                    SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,
                           ERR_R_DH_LIB);
                    goto err;
                }
            }
            r[0] = dh->p;
            r[1] = dh->g;
            r[2] = dh->pub_key;
        } else
#endif
        {
            al = SSL_AD_HANDSHAKE_FAILURE;
            SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,
                   SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE);
            goto f_err;
        }
        for (i = 0; r[i] != NULL; i++) {
            nr[i] = BN_num_bytes(r[i]);
            n += 2 + nr[i];
        }

        if (!(s->s3->tmp.new_cipher->algorithms & SSL_aNULL)) {
            if ((pkey = ssl_get_sign_pkey(s, s->s3->tmp.new_cipher))
                == NULL) {
                al = SSL_AD_DECODE_ERROR;
                goto f_err;
            }
            kn = EVP_PKEY_size(pkey);
        } else {
            pkey = NULL;
            kn = 0;
        }

        if (!BUF_MEM_grow_clean(buf, n + DTLS1_HM_HEADER_LENGTH + kn)) {
            SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE, ERR_LIB_BUF);
            goto err;
        }
        d = (unsigned char *)s->init_buf->data;
        p = &(d[DTLS1_HM_HEADER_LENGTH]);

        for (i = 0; r[i] != NULL; i++) {
            s2n(nr[i], p);
            BN_bn2bin(r[i], p);
            p += nr[i];
        }

        /* not anonymous */
        if (pkey != NULL) {
            /*
             * n is the length of the params, they start at
             * &(d[DTLS1_HM_HEADER_LENGTH]) and p points to the space at the
             * end.
             */
#ifndef OPENSSL_NO_RSA
            if (pkey->type == EVP_PKEY_RSA) {
                q = md_buf;
                j = 0;
                for (num = 2; num > 0; num--) {
                    EVP_DigestInit_ex(&md_ctx, (num == 2)
                                      ? s->ctx->md5 : s->ctx->sha1, NULL);
                    EVP_DigestUpdate(&md_ctx, &(s->s3->client_random[0]),
                                     SSL3_RANDOM_SIZE);
                    EVP_DigestUpdate(&md_ctx, &(s->s3->server_random[0]),
                                     SSL3_RANDOM_SIZE);
                    EVP_DigestUpdate(&md_ctx, &(d[DTLS1_HM_HEADER_LENGTH]),
                                     n);
                    EVP_DigestFinal_ex(&md_ctx, q, (unsigned int *)&i);
                    q += i;
                    j += i;
                }
                if (RSA_sign(NID_md5_sha1, md_buf, j,
                             &(p[2]), &u, pkey->pkey.rsa) <= 0) {
                    SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE, ERR_LIB_RSA);
                    goto err;
                }
                s2n(u, p);
                n += u + 2;
            } else
#endif
#if !defined(OPENSSL_NO_DSA)
            if (pkey->type == EVP_PKEY_DSA) {
                /* lets do DSS */
                EVP_SignInit_ex(&md_ctx, EVP_dss1(), NULL);
                EVP_SignUpdate(&md_ctx, &(s->s3->client_random[0]),
                               SSL3_RANDOM_SIZE);
                EVP_SignUpdate(&md_ctx, &(s->s3->server_random[0]),
                               SSL3_RANDOM_SIZE);
                EVP_SignUpdate(&md_ctx, &(d[DTLS1_HM_HEADER_LENGTH]), n);
                if (!EVP_SignFinal(&md_ctx, &(p[2]),
                                   (unsigned int *)&i, pkey)) {
                    SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE, ERR_LIB_DSA);
                    goto err;
                }
                s2n(i, p);
                n += i + 2;
            } else
#endif
            {
                /* Is this error check actually needed? */
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_UNKNOWN_PKEY_TYPE);
                goto f_err;
            }
        }

        d = dtls1_set_message_header(s, d,
                                     SSL3_MT_SERVER_KEY_EXCHANGE, n, 0, n);

        /*
         * we should now have things packed up, so lets send it off
         */
        s->init_num = n + DTLS1_HM_HEADER_LENGTH;
        s->init_off = 0;

        /* buffer the message to handle re-xmits */
        dtls1_buffer_message(s, 0);
    }

    s->state = SSL3_ST_SW_KEY_EXCH_B;
    EVP_MD_CTX_cleanup(&md_ctx);
    return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
 f_err:
    ssl3_send_alert(s, SSL3_AL_FATAL, al);
 err:
    EVP_MD_CTX_cleanup(&md_ctx);
    return (-1);
}

int dtls1_send_certificate_request(SSL *s)
{
    unsigned char *p, *d;
    int i, j, nl, off, n;
    STACK_OF(X509_NAME) *sk = NULL;
    X509_NAME *name;
    BUF_MEM *buf;
    unsigned int msg_len;

    if (s->state == SSL3_ST_SW_CERT_REQ_A) {
        buf = s->init_buf;

        d = p = (unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);

        /* get the list of acceptable cert types */
        p++;
        n = ssl3_get_req_cert_type(s, p);
        d[0] = n;
        p += n;
        n++;

        off = n;
        p += 2;
        n += 2;

        sk = SSL_get_client_CA_list(s);
        nl = 0;
        if (sk != NULL) {
            for (i = 0; i < sk_X509_NAME_num(sk); i++) {
                name = sk_X509_NAME_value(sk, i);
                j = i2d_X509_NAME(name, NULL);
                if (!BUF_MEM_grow_clean
                    (buf, DTLS1_HM_HEADER_LENGTH + n + j + 2)) {
                    SSLerr(SSL_F_DTLS1_SEND_CERTIFICATE_REQUEST,
                           ERR_R_BUF_LIB);
                    goto err;
                }
                p = (unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH + n]);
                if (!(s->options & SSL_OP_NETSCAPE_CA_DN_BUG)) {
                    s2n(j, p);
                    i2d_X509_NAME(name, &p);
                    n += 2 + j;
                    nl += 2 + j;
                } else {
                    d = p;
                    i2d_X509_NAME(name, &p);
                    j -= 2;
                    s2n(j, d);
                    j += 2;
                    n += j;
                    nl += j;
                }
            }
        }
        /* else no CA names */
        p = (unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH + off]);
        s2n(nl, p);

        d = (unsigned char *)buf->data;
        *(d++) = SSL3_MT_CERTIFICATE_REQUEST;
        l2n3(n, d);
        s2n(s->d1->handshake_write_seq, d);
        s->d1->handshake_write_seq++;

        /*
         * we should now have things packed up, so lets send it off
         */

        s->init_num = n + DTLS1_HM_HEADER_LENGTH;
        s->init_off = 0;
#ifdef NETSCAPE_HANG_BUG
/* XXX: what to do about this? */
        p = (unsigned char *)s->init_buf->data + s->init_num;

        /* do the header */
        *(p++) = SSL3_MT_SERVER_DONE;
        *(p++) = 0;
        *(p++) = 0;
        *(p++) = 0;
        s->init_num += 4;
#endif

        /* XDTLS:  set message header ? */
        msg_len = s->init_num - DTLS1_HM_HEADER_LENGTH;
        dtls1_set_message_header(s, (void *)s->init_buf->data,
                                 SSL3_MT_CERTIFICATE_REQUEST, msg_len, 0,
                                 msg_len);

        /* buffer the message to handle re-xmits */
        dtls1_buffer_message(s, 0);

        s->state = SSL3_ST_SW_CERT_REQ_B;
    }

    /* SSL3_ST_SW_CERT_REQ_B */
    return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
 err:
    return (-1);
}

int dtls1_send_server_certificate(SSL *s)
{
    unsigned long l;
    X509 *x;

    if (s->state == SSL3_ST_SW_CERT_A) {
        x = ssl_get_server_send_cert(s);
        if (x == NULL &&
            /* VRS: allow null cert if auth == KRB5 */
            (s->s3->tmp.new_cipher->algorithms
             & (SSL_MKEY_MASK | SSL_AUTH_MASK))
            != (SSL_aKRB5 | SSL_kKRB5)) {
            SSLerr(SSL_F_DTLS1_SEND_SERVER_CERTIFICATE, ERR_R_INTERNAL_ERROR);
            return (0);
        }

        l = dtls1_output_cert_chain(s, x);
        s->state = SSL3_ST_SW_CERT_B;
        s->init_num = (int)l;
        s->init_off = 0;

        /* buffer the message to handle re-xmits */
        dtls1_buffer_message(s, 0);
    }

    /* SSL3_ST_SW_CERT_B */
    return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
}

#ifndef OPENSSL_NO_TLSEXT
int dtls1_send_newsession_ticket(SSL *s)
{
    if (s->state == SSL3_ST_SW_SESSION_TICKET_A) {
        unsigned char *p, *senc, *macstart;
        int len, slen;
        unsigned int hlen, msg_len;
        EVP_CIPHER_CTX ctx;
        HMAC_CTX hctx;
        SSL_CTX *tctx = s->initial_ctx;
        unsigned char iv[EVP_MAX_IV_LENGTH];
        unsigned char key_name[16];

        /* get session encoding length */
        slen = i2d_SSL_SESSION(s->session, NULL);
        /*
         * Some length values are 16 bits, so forget it if session is too
         * long
         */
        if (slen > 0xFF00)
            return -1;
        /*
         * Grow buffer if need be: the length calculation is as follows 12
         * (DTLS handshake message header) + 4 (ticket lifetime hint) + 2
         * (ticket length) + 16 (key name) + max_iv_len (iv length) +
         * session_length + max_enc_block_size (max encrypted session length)
         * + max_md_size (HMAC).
         */
        if (!BUF_MEM_grow(s->init_buf,
                          DTLS1_HM_HEADER_LENGTH + 22 + EVP_MAX_IV_LENGTH +
                          EVP_MAX_BLOCK_LENGTH + EVP_MAX_MD_SIZE + slen))
            return -1;
        senc = OPENSSL_malloc(slen);
        if (!senc)
            return -1;
        p = senc;
        i2d_SSL_SESSION(s->session, &p);

        p = (unsigned char *)&(s->init_buf->data[DTLS1_HM_HEADER_LENGTH]);
        EVP_CIPHER_CTX_init(&ctx);
        HMAC_CTX_init(&hctx);
        /*
         * Initialize HMAC and cipher contexts. If callback present it does
         * all the work otherwise use generated values from parent ctx.
         */
        if (tctx->tlsext_ticket_key_cb) {
            if (tctx->tlsext_ticket_key_cb(s, key_name, iv, &ctx,
                                           &hctx, 1) < 0) {
                OPENSSL_free(senc);
                return -1;
            }
        } else {
            RAND_pseudo_bytes(iv, 16);
            EVP_EncryptInit_ex(&ctx, EVP_aes_128_cbc(), NULL,
                               tctx->tlsext_tick_aes_key, iv);
            HMAC_Init_ex(&hctx, tctx->tlsext_tick_hmac_key, 16,
                         tlsext_tick_md(), NULL);
            memcpy(key_name, tctx->tlsext_tick_key_name, 16);
        }
        l2n(s->session->tlsext_tick_lifetime_hint, p);
        /* Skip ticket length for now */
        p += 2;
        /* Output key name */
        macstart = p;
        memcpy(p, key_name, 16);
        p += 16;
        /* output IV */
        memcpy(p, iv, EVP_CIPHER_CTX_iv_length(&ctx));
        p += EVP_CIPHER_CTX_iv_length(&ctx);
        /* Encrypt session data */
        EVP_EncryptUpdate(&ctx, p, &len, senc, slen);
        p += len;
        EVP_EncryptFinal(&ctx, p, &len);
        p += len;
        EVP_CIPHER_CTX_cleanup(&ctx);

        HMAC_Update(&hctx, macstart, p - macstart);
        HMAC_Final(&hctx, p, &hlen);
        HMAC_CTX_cleanup(&hctx);

        p += hlen;
        /* Now write out lengths: p points to end of data written */
        /* Total length */
        len = p - (unsigned char *)(s->init_buf->data);
        /* Ticket length */
        p = (unsigned char *)&(s->init_buf->data[DTLS1_HM_HEADER_LENGTH]) + 4;
        s2n(len - DTLS1_HM_HEADER_LENGTH - 6, p);

        /* number of bytes to write */
        s->init_num = len;
        s->state = SSL3_ST_SW_SESSION_TICKET_B;
        s->init_off = 0;
        OPENSSL_free(senc);

        /* XDTLS:  set message header ? */
        msg_len = s->init_num - DTLS1_HM_HEADER_LENGTH;
        dtls1_set_message_header(s, (void *)s->init_buf->data,
                                 SSL3_MT_NEWSESSION_TICKET, msg_len, 0,
                                 msg_len);

        /* buffer the message to handle re-xmits */
        dtls1_buffer_message(s, 0);
    }

    /* SSL3_ST_SW_SESSION_TICKET_B */
    return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
}
#endif