openssl/crypto/bio/bss_dgram.c

/* crypto/bio/bio_dgram.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).
 *
 */

#include <stdio.h>
#include <errno.h>
#define USE_SOCKETS
#include "cryptlib.h"

#include <openssl/bio.h>
#ifndef OPENSSL_NO_DGRAM

# if defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VMS)
#  include <sys/timeb.h>
# endif

# ifdef OPENSSL_SYS_LINUX
#  define IP_MTU      14        /* linux is lame */
# endif

# ifdef WATT32
#  define sock_write SockWrite  /* Watt-32 uses same names */
#  define sock_read  SockRead
#  define sock_puts  SockPuts
# endif

static int dgram_write(BIO *h, const char *buf, int num);
static int dgram_read(BIO *h, char *buf, int size);
static int dgram_puts(BIO *h, const char *str);
static long dgram_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int dgram_new(BIO *h);
static int dgram_free(BIO *data);
static int dgram_clear(BIO *bio);

static int BIO_dgram_should_retry(int s);

static void get_current_time(struct timeval *t);

static BIO_METHOD methods_dgramp = {
    BIO_TYPE_DGRAM,
    "datagram socket",
    dgram_write,
    dgram_read,
    dgram_puts,
    NULL,                       /* dgram_gets, */
    dgram_ctrl,
    dgram_new,
    dgram_free,
    NULL,
};

typedef struct bio_dgram_data_st {
    union {
        struct sockaddr sa;
        struct sockaddr_in sa_in;
# if OPENSSL_USE_IPV6
        struct sockaddr_in6 sa_in6;
# endif
    } peer;
    unsigned int connected;
    unsigned int _errno;
    unsigned int mtu;
    struct timeval next_timeout;
    struct timeval socket_timeout;
} bio_dgram_data;

BIO_METHOD *BIO_s_datagram(void)
{
    return (&methods_dgramp);
}

BIO *BIO_new_dgram(int fd, int close_flag)
{
    BIO *ret;

    ret = BIO_new(BIO_s_datagram());
    if (ret == NULL)
        return (NULL);
    BIO_set_fd(ret, fd, close_flag);
    return (ret);
}

static int dgram_new(BIO *bi)
{
    bio_dgram_data *data = NULL;

    bi->init = 0;
    bi->num = 0;
    data = OPENSSL_malloc(sizeof(bio_dgram_data));
    if (data == NULL)
        return 0;
    memset(data, 0x00, sizeof(bio_dgram_data));
    bi->ptr = data;

    bi->flags = 0;
    return (1);
}

static int dgram_free(BIO *a)
{
    bio_dgram_data *data;

    if (a == NULL)
        return (0);
    if (!dgram_clear(a))
        return 0;

    data = (bio_dgram_data *)a->ptr;
    if (data != NULL)
        OPENSSL_free(data);

    return (1);
}

static int dgram_clear(BIO *a)
{
    if (a == NULL)
        return (0);
    if (a->shutdown) {
        if (a->init) {
            SHUTDOWN2(a->num);
        }
        a->init = 0;
        a->flags = 0;
    }
    return (1);
}

static void dgram_adjust_rcv_timeout(BIO *b)
{
# if defined(SO_RCVTIMEO)
    bio_dgram_data *data = (bio_dgram_data *)b->ptr;
    union {
        size_t s;
        int i;
    } sz = {
        0
    };

    /* Is a timer active? */
    if (data->next_timeout.tv_sec > 0 || data->next_timeout.tv_usec > 0) {
        struct timeval timenow, timeleft;

        /* Read current socket timeout */
#  ifdef OPENSSL_SYS_WINDOWS
        int timeout;

        sz.i = sizeof(timeout);
        if (getsockopt(b->num, SOL_SOCKET, SO_RCVTIMEO,
                       (void *)&timeout, &sz.i) < 0) {
            perror("getsockopt");
        } else {
            data->socket_timeout.tv_sec = timeout / 1000;
            data->socket_timeout.tv_usec = (timeout % 1000) * 1000;
        }
#  else
        sz.i = sizeof(data->socket_timeout);
        if (getsockopt(b->num, SOL_SOCKET, SO_RCVTIMEO,
                       &(data->socket_timeout), (void *)&sz) < 0) {
            perror("getsockopt");
        } else if (sizeof(sz.s) != sizeof(sz.i) && sz.i == 0)
            OPENSSL_assert(sz.s <= sizeof(data->socket_timeout));
#  endif

        /* Get current time */
        get_current_time(&timenow);

        /* Calculate time left until timer expires */
        memcpy(&timeleft, &(data->next_timeout), sizeof(struct timeval));
        timeleft.tv_sec -= timenow.tv_sec;
        timeleft.tv_usec -= timenow.tv_usec;
        if (timeleft.tv_usec < 0) {
            timeleft.tv_sec--;
            timeleft.tv_usec += 1000000;
        }

        if (timeleft.tv_sec < 0) {
            timeleft.tv_sec = 0;
            timeleft.tv_usec = 1;
        }

        /*
         * Adjust socket timeout if next handhake message timer will expire
         * earlier.
         */
        if ((data->socket_timeout.tv_sec == 0
             && data->socket_timeout.tv_usec == 0)
            || (data->socket_timeout.tv_sec > timeleft.tv_sec)
            || (data->socket_timeout.tv_sec == timeleft.tv_sec
                && data->socket_timeout.tv_usec >= timeleft.tv_usec)) {
#  ifdef OPENSSL_SYS_WINDOWS
            timeout = timeleft.tv_sec * 1000 + timeleft.tv_usec / 1000;
            if (setsockopt(b->num, SOL_SOCKET, SO_RCVTIMEO,
                           (void *)&timeout, sizeof(timeout)) < 0) {
                perror("setsockopt");
            }
#  else
            if (setsockopt(b->num, SOL_SOCKET, SO_RCVTIMEO, &timeleft,
                           sizeof(struct timeval)) < 0) {
                perror("setsockopt");
            }
#  endif
        }
    }
# endif
}

static void dgram_reset_rcv_timeout(BIO *b)
{
# if defined(SO_RCVTIMEO)
    bio_dgram_data *data = (bio_dgram_data *)b->ptr;

    /* Is a timer active? */
    if (data->next_timeout.tv_sec > 0 || data->next_timeout.tv_usec > 0) {
#  ifdef OPENSSL_SYS_WINDOWS
        int timeout = data->socket_timeout.tv_sec * 1000 +
            data->socket_timeout.tv_usec / 1000;
        if (setsockopt(b->num, SOL_SOCKET, SO_RCVTIMEO,
                       (void *)&timeout, sizeof(timeout)) < 0) {
            perror("setsockopt");
        }
#  else
        if (setsockopt
            (b->num, SOL_SOCKET, SO_RCVTIMEO, &(data->socket_timeout),
             sizeof(struct timeval)) < 0) {
            perror("setsockopt");
        }
#  endif
    }
# endif
}

static int dgram_read(BIO *b, char *out, int outl)
{
    int ret = 0;
    bio_dgram_data *data = (bio_dgram_data *)b->ptr;

    struct {
        /*
         * See commentary in b_sock.c. <appro>
         */
        union {
            size_t s;
            int i;
        } len;
        union {
            struct sockaddr sa;
            struct sockaddr_in sa_in;
# if OPENSSL_USE_IPV6
            struct sockaddr_in6 sa_in6;
# endif
        } peer;
    } sa;

    sa.len.s = 0;
    sa.len.i = sizeof(sa.peer);

    if (out != NULL) {
        clear_socket_error();
        memset(&sa.peer, 0x00, sizeof(sa.peer));
        dgram_adjust_rcv_timeout(b);
        ret = recvfrom(b->num, out, outl, 0, &sa.peer.sa, (void *)&sa.len);
        if (sizeof(sa.len.i) != sizeof(sa.len.s) && sa.len.i == 0) {
            OPENSSL_assert(sa.len.s <= sizeof(sa.peer));
            sa.len.i = (int)sa.len.s;
        }

        if (!data->connected && ret >= 0)
            BIO_ctrl(b, BIO_CTRL_DGRAM_SET_PEER, 0, &sa.peer);

        BIO_clear_retry_flags(b);
        if (ret < 0) {
            if (BIO_dgram_should_retry(ret)) {
                BIO_set_retry_read(b);
                data->_errno = get_last_socket_error();
            }
        }

        dgram_reset_rcv_timeout(b);
    }
    return (ret);
}

static int dgram_write(BIO *b, const char *in, int inl)
{
    int ret;
    bio_dgram_data *data = (bio_dgram_data *)b->ptr;
    clear_socket_error();

    if (data->connected)
        ret = writesocket(b->num, in, inl);
    else {
        int peerlen = sizeof(data->peer);

        if (data->peer.sa.sa_family == AF_INET)
            peerlen = sizeof(data->peer.sa_in);
# if OPENSSL_USE_IPV6
        else if (data->peer.sa.sa_family == AF_INET6)
            peerlen = sizeof(data->peer.sa_in6);
# endif
# if defined(NETWARE_CLIB) && defined(NETWARE_BSDSOCK)
        ret = sendto(b->num, (char *)in, inl, 0, &data->peer.sa, peerlen);
# else
        ret = sendto(b->num, in, inl, 0, &data->peer.sa, peerlen);
# endif
    }

    BIO_clear_retry_flags(b);
    if (ret <= 0) {
        if (BIO_dgram_should_retry(ret)) {
            BIO_set_retry_write(b);
            data->_errno = get_last_socket_error();

# if 0                          /* higher layers are responsible for querying
                                 * MTU, if necessary */
            if (data->_errno == EMSGSIZE)
                /* retrieve the new MTU */
                BIO_ctrl(b, BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
# endif
        }
    }
    return (ret);
}

static long dgram_get_mtu_overhead(bio_dgram_data *data)
{
    long ret;

    switch (data->peer.sa.sa_family) {
    case AF_INET:
        /*
         * Assume this is UDP - 20 bytes for IP, 8 bytes for UDP
         */
        ret = 28;
        break;
# if OPENSSL_USE_IPV6
    case AF_INET6:
#  ifdef IN6_IS_ADDR_V4MAPPED
        if (IN6_IS_ADDR_V4MAPPED(&data->peer.sa_in6.sin6_addr))
            /*
             * Assume this is UDP - 20 bytes for IP, 8 bytes for UDP
             */
            ret = 28;
        else
#  endif
            /*
             * Assume this is UDP - 40 bytes for IP, 8 bytes for UDP
             */
            ret = 48;
        break;
# endif
    default:
        /* We don't know. Go with the historical default */
        ret = 28;
        break;
    }
    return ret;
}

static long dgram_ctrl(BIO *b, int cmd, long num, void *ptr)
{
    long ret = 1;
    int *ip;
    struct sockaddr *to = NULL;
    bio_dgram_data *data = NULL;
# if defined(OPENSSL_SYS_LINUX) && (defined(IP_MTU_DISCOVER) || defined(IP_MTU))
    int sockopt_val = 0;
    socklen_t sockopt_len;      /* assume that system supporting IP_MTU is
                                 * modern enough to define socklen_t */
    socklen_t addr_len;
    union {
        struct sockaddr sa;
        struct sockaddr_in s4;
#  if OPENSSL_USE_IPV6
        struct sockaddr_in6 s6;
#  endif
    } addr;
# endif

    data = (bio_dgram_data *)b->ptr;

    switch (cmd) {
    case BIO_CTRL_RESET:
        num = 0;
    case BIO_C_FILE_SEEK:
        ret = 0;
        break;
    case BIO_C_FILE_TELL:
    case BIO_CTRL_INFO:
        ret = 0;
        break;
    case BIO_C_SET_FD:
        dgram_clear(b);
        b->num = *((int *)ptr);
        b->shutdown = (int)num;
        b->init = 1;
        break;
    case BIO_C_GET_FD:
        if (b->init) {
            ip = (int *)ptr;
            if (ip != NULL)
                *ip = b->num;
            ret = b->num;
        } else
            ret = -1;
        break;
    case BIO_CTRL_GET_CLOSE:
        ret = b->shutdown;
        break;
    case BIO_CTRL_SET_CLOSE:
        b->shutdown = (int)num;
        break;
    case BIO_CTRL_PENDING:
    case BIO_CTRL_WPENDING:
        ret = 0;
        break;
    case BIO_CTRL_DUP:
    case BIO_CTRL_FLUSH:
        ret = 1;
        break;
    case BIO_CTRL_DGRAM_CONNECT:
        to = (struct sockaddr *)ptr;
# if 0
        if (connect(b->num, to, sizeof(struct sockaddr)) < 0) {
            perror("connect");
            ret = 0;
        } else {
# endif
            switch (to->sa_family) {
            case AF_INET:
                memcpy(&data->peer, to, sizeof(data->peer.sa_in));
                break;
# if OPENSSL_USE_IPV6
            case AF_INET6:
                memcpy(&data->peer, to, sizeof(data->peer.sa_in6));
                break;
# endif
            default:
                memcpy(&data->peer, to, sizeof(data->peer.sa));
                break;
            }
# if 0
        }
# endif
        break;
        /* (Linux)kernel sets DF bit on outgoing IP packets */
    case BIO_CTRL_DGRAM_MTU_DISCOVER:
# if defined(OPENSSL_SYS_LINUX) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
        addr_len = (socklen_t) sizeof(addr);
        memset((void *)&addr, 0, sizeof(addr));
        if (getsockname(b->num, &addr.sa, &addr_len) < 0) {
            ret = 0;
            break;
        }
        switch (addr.sa.sa_family) {
        case AF_INET:
            sockopt_val = IP_PMTUDISC_DO;
            if ((ret = setsockopt(b->num, IPPROTO_IP, IP_MTU_DISCOVER,
                                  &sockopt_val, sizeof(sockopt_val))) < 0)
                perror("setsockopt");
            break;
#  if OPENSSL_USE_IPV6 && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
        case AF_INET6:
            sockopt_val = IPV6_PMTUDISC_DO;
            if ((ret = setsockopt(b->num, IPPROTO_IPV6, IPV6_MTU_DISCOVER,
                                  &sockopt_val, sizeof(sockopt_val))) < 0)
                perror("setsockopt");
            break;
#  endif
        default:
            ret = -1;
            break;
        }
        ret = -1;
# else
        break;
# endif
    case BIO_CTRL_DGRAM_QUERY_MTU:
# if defined(OPENSSL_SYS_LINUX) && defined(IP_MTU)
        addr_len = (socklen_t) sizeof(addr);
        memset((void *)&addr, 0, sizeof(addr));
        if (getsockname(b->num, &addr.sa, &addr_len) < 0) {
            ret = 0;
            break;
        }
        sockopt_len = sizeof(sockopt_val);
        switch (addr.sa.sa_family) {
        case AF_INET:
            if ((ret =
                 getsockopt(b->num, IPPROTO_IP, IP_MTU, (void *)&sockopt_val,
                            &sockopt_len)) < 0 || sockopt_val < 0) {
                ret = 0;
            } else {
                /*
                 * we assume that the transport protocol is UDP and no IP
                 * options are used.
                 */
                data->mtu = sockopt_val - 8 - 20;
                ret = data->mtu;
            }
            break;
#  if OPENSSL_USE_IPV6 && defined(IPV6_MTU)
        case AF_INET6:
            if ((ret =
                 getsockopt(b->num, IPPROTO_IPV6, IPV6_MTU,
                            (void *)&sockopt_val, &sockopt_len)) < 0
                || sockopt_val < 0) {
                ret = 0;
            } else {
                /*
                 * we assume that the transport protocol is UDP and no IPV6
                 * options are used.
                 */
                data->mtu = sockopt_val - 8 - 40;
                ret = data->mtu;
            }
            break;
#  endif
        default:
            ret = 0;
            break;
        }
# else
        ret = 0;
# endif
        break;
    case BIO_CTRL_DGRAM_GET_FALLBACK_MTU:
        ret = -dgram_get_mtu_overhead(data);
        switch (data->peer.sa.sa_family) {
        case AF_INET:
            ret += 576;
            break;
# if OPENSSL_USE_IPV6
        case AF_INET6:
#  ifdef IN6_IS_ADDR_V4MAPPED
            if (IN6_IS_ADDR_V4MAPPED(&data->peer.sa_in6.sin6_addr))
                ret += 576;
            else
#  endif
                ret += 1280;
            break;
# endif
        default:
            ret += 576;
            break;
        }
        break;
    case BIO_CTRL_DGRAM_GET_MTU:
        return data->mtu;
        break;
    case BIO_CTRL_DGRAM_SET_MTU:
        data->mtu = num;
        ret = num;
        break;
    case BIO_CTRL_DGRAM_SET_CONNECTED:
        to = (struct sockaddr *)ptr;

        if (to != NULL) {
            data->connected = 1;
            switch (to->sa_family) {
            case AF_INET:
                memcpy(&data->peer, to, sizeof(data->peer.sa_in));
                break;
# if OPENSSL_USE_IPV6
            case AF_INET6:
                memcpy(&data->peer, to, sizeof(data->peer.sa_in6));
                break;
# endif
            default:
                memcpy(&data->peer, to, sizeof(data->peer.sa));
                break;
            }
        } else {
            data->connected = 0;
            memset(&(data->peer), 0x00, sizeof(data->peer));
        }
        break;
    case BIO_CTRL_DGRAM_GET_PEER:
        switch (data->peer.sa.sa_family) {
        case AF_INET:
            ret = sizeof(data->peer.sa_in);
            break;
# if OPENSSL_USE_IPV6
        case AF_INET6:
            ret = sizeof(data->peer.sa_in6);
            break;
# endif
        default:
            ret = sizeof(data->peer.sa);
            break;
        }
        if (num == 0 || num > ret)
            num = ret;
        memcpy(ptr, &data->peer, (ret = num));
        break;
    case BIO_CTRL_DGRAM_SET_PEER:
        to = (struct sockaddr *)ptr;
        switch (to->sa_family) {
        case AF_INET:
            memcpy(&data->peer, to, sizeof(data->peer.sa_in));
            break;
# if OPENSSL_USE_IPV6
        case AF_INET6:
            memcpy(&data->peer, to, sizeof(data->peer.sa_in6));
            break;
# endif
        default:
            memcpy(&data->peer, to, sizeof(data->peer.sa));
            break;
        }
        break;
    case BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT:
        memcpy(&(data->next_timeout), ptr, sizeof(struct timeval));
        break;
# if defined(SO_RCVTIMEO)
    case BIO_CTRL_DGRAM_SET_RECV_TIMEOUT:
#  ifdef OPENSSL_SYS_WINDOWS
        {
            struct timeval *tv = (struct timeval *)ptr;
            int timeout = tv->tv_sec * 1000 + tv->tv_usec / 1000;
            if (setsockopt(b->num, SOL_SOCKET, SO_RCVTIMEO,
                           (void *)&timeout, sizeof(timeout)) < 0) {
                perror("setsockopt");
                ret = -1;
            }
        }
#  else
        if (setsockopt(b->num, SOL_SOCKET, SO_RCVTIMEO, ptr,
                       sizeof(struct timeval)) < 0) {
            perror("setsockopt");
            ret = -1;
        }
#  endif
        break;
    case BIO_CTRL_DGRAM_GET_RECV_TIMEOUT:
        {
            union {
                size_t s;
                int i;
            } sz = {
                0
            };
#  ifdef OPENSSL_SYS_WINDOWS
            int timeout;
            struct timeval *tv = (struct timeval *)ptr;

            sz.i = sizeof(timeout);
            if (getsockopt(b->num, SOL_SOCKET, SO_RCVTIMEO,
                           (void *)&timeout, &sz.i) < 0) {
                perror("getsockopt");
                ret = -1;
            } else {
                tv->tv_sec = timeout / 1000;
                tv->tv_usec = (timeout % 1000) * 1000;
                ret = sizeof(*tv);
            }
#  else
            sz.i = sizeof(struct timeval);
            if (getsockopt(b->num, SOL_SOCKET, SO_RCVTIMEO,
                           ptr, (void *)&sz) < 0) {
                perror("getsockopt");
                ret = -1;
            } else if (sizeof(sz.s) != sizeof(sz.i) && sz.i == 0) {
                OPENSSL_assert(sz.s <= sizeof(struct timeval));
                ret = (int)sz.s;
            } else
                ret = sz.i;
#  endif
        }
        break;
# endif
# if defined(SO_SNDTIMEO)
    case BIO_CTRL_DGRAM_SET_SEND_TIMEOUT:
#  ifdef OPENSSL_SYS_WINDOWS
        {
            struct timeval *tv = (struct timeval *)ptr;
            int timeout = tv->tv_sec * 1000 + tv->tv_usec / 1000;
            if (setsockopt(b->num, SOL_SOCKET, SO_SNDTIMEO,
                           (void *)&timeout, sizeof(timeout)) < 0) {
                perror("setsockopt");
                ret = -1;
            }
        }
#  else
        if (setsockopt(b->num, SOL_SOCKET, SO_SNDTIMEO, ptr,
                       sizeof(struct timeval)) < 0) {
            perror("setsockopt");
            ret = -1;
        }
#  endif
        break;
    case BIO_CTRL_DGRAM_GET_SEND_TIMEOUT:
        {
            union {
                size_t s;
                int i;
            } sz = {
                0
            };
#  ifdef OPENSSL_SYS_WINDOWS
            int timeout;
            struct timeval *tv = (struct timeval *)ptr;

            sz.i = sizeof(timeout);
            if (getsockopt(b->num, SOL_SOCKET, SO_SNDTIMEO,
                           (void *)&timeout, &sz.i) < 0) {
                perror("getsockopt");
                ret = -1;
            } else {
                tv->tv_sec = timeout / 1000;
                tv->tv_usec = (timeout % 1000) * 1000;
                ret = sizeof(*tv);
            }
#  else
            sz.i = sizeof(struct timeval);
            if (getsockopt(b->num, SOL_SOCKET, SO_SNDTIMEO,
                           ptr, (void *)&sz) < 0) {
                perror("getsockopt");
                ret = -1;
            } else if (sizeof(sz.s) != sizeof(sz.i) && sz.i == 0) {
                OPENSSL_assert(sz.s <= sizeof(struct timeval));
                ret = (int)sz.s;
            } else
                ret = sz.i;
#  endif
        }
        break;
# endif
    case BIO_CTRL_DGRAM_GET_SEND_TIMER_EXP:
        /* fall-through */
    case BIO_CTRL_DGRAM_GET_RECV_TIMER_EXP:
# ifdef OPENSSL_SYS_WINDOWS
        if (data->_errno == WSAETIMEDOUT)
# else
        if (data->_errno == EAGAIN)
# endif
        {
            ret = 1;
            data->_errno = 0;
        } else
            ret = 0;
        break;
# ifdef EMSGSIZE
    case BIO_CTRL_DGRAM_MTU_EXCEEDED:
        if (data->_errno == EMSGSIZE) {
            ret = 1;
            data->_errno = 0;
        } else
            ret = 0;
        break;
# endif
    case BIO_CTRL_DGRAM_GET_MTU_OVERHEAD:
        ret = dgram_get_mtu_overhead(data);
        break;
    default:
        ret = 0;
        break;
    }
    return (ret);
}

static int dgram_puts(BIO *bp, const char *str)
{
    int n, ret;

    n = strlen(str);
    ret = dgram_write(bp, str, n);
    return (ret);
}

static int BIO_dgram_should_retry(int i)
{
    int err;

    if ((i == 0) || (i == -1)) {
        err = get_last_socket_error();

# if defined(OPENSSL_SYS_WINDOWS)
        /*
         * If the socket return value (i) is -1 and err is unexpectedly 0 at
         * this point, the error code was overwritten by another system call
         * before this error handling is called.
         */
# endif

        return (BIO_dgram_non_fatal_error(err));
    }
    return (0);
}

int BIO_dgram_non_fatal_error(int err)
{
    switch (err) {
# if defined(OPENSSL_SYS_WINDOWS)
#  if defined(WSAEWOULDBLOCK)
    case WSAEWOULDBLOCK:
#  endif

#  if 0                         /* This appears to always be an error */
#   if defined(WSAENOTCONN)
    case WSAENOTCONN:
#   endif
#  endif
# endif

# ifdef EWOULDBLOCK
#  ifdef WSAEWOULDBLOCK
#   if WSAEWOULDBLOCK != EWOULDBLOCK
    case EWOULDBLOCK:
#   endif
#  else
    case EWOULDBLOCK:
#  endif
# endif

# ifdef EINTR
    case EINTR:
# endif

# ifdef EAGAIN
#  if EWOULDBLOCK != EAGAIN
    case EAGAIN:
#  endif
# endif

# ifdef EPROTO
    case EPROTO:
# endif

# ifdef EINPROGRESS
    case EINPROGRESS:
# endif

# ifdef EALREADY
    case EALREADY:
# endif

        return (1);
        /* break; */
    default:
        break;
    }
    return (0);
}

static void get_current_time(struct timeval *t)
{
# ifdef OPENSSL_SYS_WIN32
    struct _timeb tb;
    _ftime(&tb);
    t->tv_sec = (long)tb.time;
    t->tv_usec = (long)tb.millitm * 1000;
# elif defined(OPENSSL_SYS_VMS)
    struct timeb tb;
    ftime(&tb);
    t->tv_sec = (long)tb.time;
    t->tv_usec = (long)tb.millitm * 1000;
# else
    gettimeofday(t, NULL);
# endif
}

#endif