c发邮件

/* base64编码 */
static const char* base64_enc_map = 
                                    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
int base64_encode( char* dst, size_t* dlen, const unsigned char* src, size_t slen )
{
    size_t i, n;
    int C1, C2, C3;
    char* p;

    if ( slen == 0 )
    {
        return 0;
    }

    n = ( slen << 3 ) / 6;

    switch ( ( slen << 3 ) - ( n * 6 ) )
    {
        case  2:
            n += 3;
            break;
        case  4:
            n += 2;
            break;
        default:
            break;
    }

    if ( *dlen < n + 1 )
    {
        *dlen = n + 1;
        return -1;
    }

    n = ( slen / 3 ) * 3;
    for ( i = 0, p = dst; i < n; i += 3 )
    {
        C1 = *src++;
        C2 = *src++;
        C3 = *src++;
        *p++ = base64_enc_map[( C1 >> 2 ) & 0x3F];
        *p++ = base64_enc_map[( ( ( C1 &  3 ) << 4 ) + ( C2 >> 4 ) ) & 0x3F];
        *p++ = base64_enc_map[( ( ( C2 & 15 ) << 2 ) + ( C3 >> 6 ) ) & 0x3F];
        *p++ = base64_enc_map[C3 & 0x3F];
    }

    if ( i < slen )
    {
        C1 = *src++;
        C2 = ( ( i + 1 ) < slen ) ? *src++ : 0;
        *p++ = base64_enc_map[( C1 >> 2 ) & 0x3F];
        *p++ = base64_enc_map[( ( ( C1 & 3 ) << 4 ) + ( C2 >> 4 ) ) & 0x3F];
        ( i + 1 ) < slen ? ( *p++ = base64_enc_map[( ( C2 & 15 ) << 2 ) & 0x3F] ) : ( *p++ = '=' );
        *p++ = '=';
    }

    *dlen = p - dst;
    *p = 0;

    return 0;
}

/* 主动连接 */
static SOCKET tcp_connect( const char* host, unsigned short port = 25, int msec = 100 )
{
    int ret;
    SOCKET fd;
    struct sockaddr_in sin;
    struct hostent* h;
    unsigned long ul;
    struct timeval tv;
    struct linger lg;
    int nodelay;
    fd_set fdset;

    /* 填充服务器地址 */
    memset( &sin, 0, sizeof( sin ) );
    sin.sin_family = AF_INET;
    if ( ( h = gethostbyname( host ) ) == NULL || h->h_addrtype != AF_INET )
    {
        return INVALID_SOCKET;
    }
    memcpy( &sin.sin_addr.S_un.S_addr, h->h_addr, h->h_length );
    sin.sin_port = htons( port );


    /* 建socket */
    if ( ( fd = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP ) ) ==  INVALID_SOCKET )
    {
        return INVALID_SOCKET;
    }

    /* 设置非阻塞 */
    ul = 1;
    if ( ioctlsocket( fd, FIONBIO, &ul ) != 0 )
    {
        closesocket( fd );
        return INVALID_SOCKET;
    }

    /* 主动连接 */
    if ( connect( fd, ( const struct sockaddr* ) &sin, sizeof( sin ) ) != 0 )
    {
        FD_ZERO( &fdset );
        FD_SET( fd, &fdset );

        memset( &tv, 0, sizeof( tv ) );
        tv.tv_sec = msec / 1000;
        tv.tv_usec = ( msec % 1000 ) * 1000;

        /* 超时或报错 */
        if ( select( fd + 1, 0, &fdset, 0, &tv ) != 1 )
        {
            closesocket( fd );
            return INVALID_SOCKET;
        }
    }

    /* 置为阻塞 */
    ul = 0;
    ret = ioctlsocket( fd, FIONBIO, &ul );
    assert( ret == 0 );

    /*消除滞留*/
    memset( &lg, 0, sizeof( lg ) );
    ret = setsockopt( fd, SOL_SOCKET, SO_LINGER, ( const char* ) &lg, sizeof( lg ) );
    assert( ret == 0 );

    /*禁用合并*/
    nodelay = 1;
    ret = setsockopt( fd, IPPROTO_TCP, TCP_NODELAY, ( const char* ) &nodelay, sizeof( nodelay ) );
    assert( ret == 0 );

    return fd;
}


#define RECV(fd, buff, suc) do { 
        if (recv( (fd), (buff), sizeof( (buff) ), 0 ) <= 0 || 
                memcmp((buff), (suc), 3)) 
        { 
            closesocket((fd)); 
            return -1; 
        } 
    }while(0)


#define SEND(fd, buff, len) do { 
        register size_t i = (len); 
        if (send( (fd), (buff), i, 0 ) < (int)i) 
        { 
            closesocket((fd)); 
            return -1; 
        } 
    }while(0)


/* 发邮件 */
int send_mail( const char* server,
               const char* user, const char* pwd, 
               const char* sender, const char* receiver, 
               const char* str, const unsigned char* data, size_t datalen )
{
    SOCKET fd;
    char buff[1024];
    size_t len;
    size_t pos;

    /* 连接SMTP服务器 */
    fd = tcp_connect( server );
    if ( fd == INVALID_SOCKET )
    {
        ::MessageBox( NULL, "无法连接服务器，请检查网络设备！", "错误", MB_OK );
        return -1;
    }

    /* 邮件问答 */
    RECV( fd, buff, "220" );

    sprintf( buff, "HELO %s
", server );
    SEND( fd, buff, strlen( buff ) );
    RECV( fd, buff, "250" );

    /* 登录过程 */
    SEND( fd, "AUTH LOGIN
", 12 ); /* 请求登录 */
    RECV( fd, buff, "334" );

    len = sizeof( buff );
    base64_encode( buff, &len, ( const unsigned char* )user, strlen( user ) );
    strcat( buff, "
" );
    SEND( fd, buff, len + 2 ); /* 用户名 */
    RECV( fd, buff, "334" );

    len = sizeof( buff );
    base64_encode( buff, &len, ( const unsigned char* )pwd, strlen( pwd ) );
    strcat( buff, "
" );
    SEND( fd, buff, len + 2 ); /* 密码 */
    RECV( fd, buff, "235" );

    /* 邮件头 */
    sprintf( buff, "MAIL FROM:<%s>
", sender );
    SEND( fd, buff, strlen( buff ) ); /* 发送者 */
    RECV( fd, buff, "250" ); /* 250 Ok... */

    sprintf( buff, "RCPT TO:<%s>
", receiver );
    SEND( fd, buff, strlen( buff ) ); /* 接收者 */
    RECV( fd, buff, "250" );

    SEND( fd, "DATA
", 6 ); /* 请求发送数据 */
    RECV( fd, buff, "354" );

    sprintf( buff, "From:"javadotest"<%s>
"
             "To:"javado"<%s>
"
             "Subject:邮件标题
"
             "MIME-Version: 1.0
"
             "Content-Type: multipart/mixed; boundary="o0o0o0o0o"

", 
             sender, receiver );
    SEND( fd, buff, strlen( buff ) );


    /* 发送邮件内容 */
    sprintf( buff, "--o0o0o0o0o
"
             "Content-Type: text/plain; charset="gb2312"

"
             "%s

", str );
    SEND( fd, buff, strlen( buff ) );




    /* 发送附件 */
    strcpy( buff, "--o0o0o0o0o
"
            "Content-Type: application/octet-stream; name="附件.doc"
"
            "Content-Transfer-Encoding: base64
"
            "Content-Disposition: attachment; filename="附件.doc"

" );
    SEND( fd, buff, strlen( buff ) );
    if ( datalen > 0 )
    {
        for ( pos = 0; pos < datalen; )
        {
            len = sizeof( buff );
            memset( buff, 0, sizeof( buff ) );

            if ( datalen - pos >= 765 )
            {
                base64_encode( buff, &len, data + pos, 765 );
                strcat( buff, "
" );
                SEND( fd, buff, 1022 );
                pos += 765;
            }
            else
            {
                base64_encode( buff, &len, data + pos, datalen - pos );
                strcat( buff, "
" );
                SEND( fd, buff, strlen( buff ) );
                break;
            }
        }
    }



    /* 完成发送 */
    SEND( fd, "--o0o0o0o0o--
.
QUIT
", 24 ); /* 请求退出 */
    RECV( fd, buff, "250" ); /* 250 Ok */

    closesocket( fd );
    return 0;
}