/*
 * Copyright (C) 2015 Benjamin Fry <benjaminfry@me.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#![deny(missing_docs)]
#![recursion_limit = "1024"]

//! Trust-DNS is intended to be a fully compliant domain name server and client library.
//!
//! The Client library is responsible for the basic protocols responsible for communicating with DNS servers (authorities) and resolvers. It can be used for managing DNS records through the use of update operations. It is possible to send raw DNS Messages with the Client, but for ease of use the `query` and various other update operations are recommended for general use.
//!
//! For a system like resolver built on top of the Client library, see [trust-dns-resolver](https://docs.rs/trust-dns-resolver). This is mostlikely what you want if all you want to do is lookup IP addresses.
//!
//! For serving DNS serving, see [trust-dns-server](https://docs.rs/trust-dns-server).
//!
//! # Goals
//!
//! * Only safe Rust
//! * All errors handled
//! * Simple to manage servers
//! * High level abstraction for clients
//! * Secure dynamic update
//! * New features for securing public information
//!
//! # Usage
//!
//! This shows basic usage of the SyncClient. More examples will be associated directly with other types.
//!
//! ## Dependency
//!
//! ```toml
//! [dependencies]
//! trust-dns = "^0.10"
//! ```
//!
//! By default DNSSec validation is built in with OpenSSL, this can be disabled with:
//!
//! ```toml
//! [dependencies]
//! trust-dns = { version = "^0.10", default-features = false }
//! ```
//!
//! Extern the crate into your program or library:
//!
//! ```rust
//! extern crate trust_dns;
//! ```
//!
//! ## Objects
//!
//! There are two variations of implementations of the Client. The `SyncClient`, a synchronous client, and the `ClientFuture`, a Tokio async client. `SyncClient` is an implementation of the `Client` trait, there is another implementation, `SecureSyncClient`, which validates DNSSec records. For these basic examples we'll only look at the `SyncClient`
//!
//! First we must decide on the type of connection, there are three supported by TRust-DNS today, UDP, TCP and TLS. TLS requires OpenSSL by default, see also [trust-dns-native-tls](https://docs.rs/trust-dns-native-tls) and [trust-dns-rustls](https://docs.rs/trust-dns-rustls) for other TLS options.
//!
//! ## Setup a connection
//!
//! ```rust
//! use trust_dns::client::{Client, ClientConnection, ClientStreamHandle, SyncClient};
//! use trust_dns::udp::UdpClientConnection;
//!
//! let address = "8.8.8.8:53".parse().unwrap();
//! let conn = UdpClientConnection::new(address).unwrap();
//!
//! // and then create the Client
//! let client = SyncClient::new(conn);
//! ```
//!
//! At this point the client is ready to be used. See also `client::SecureSyncClient` for DNSSec validation. The rest of these examples will assume that the above boilerplate has already been performed.
//!
//! ## Querying
//!
//! Using the Client to query for DNS records is easy enough, though it performs no resolution. The `trust-dns-resolver` has a simpler interface if that's what is desired. Over time that library will gain more features to generically query for differnet types.
//!
//! ```rust
//! use std::net::Ipv4Addr;
//! use std::str::FromStr;
//! # use trust_dns::client::{Client, SyncClient};
//! # use trust_dns::udp::UdpClientConnection;
//! use trust_dns::op::Message;
//! use trust_dns::rr::{DNSClass, Name, RData, Record, RecordType};
//! #
//! # let address = "8.8.8.8:53".parse().unwrap();
//! # let conn = UdpClientConnection::new(address).unwrap();
//! # let client = SyncClient::new(conn);
//!
//! // Specify the name, note the final '.' which specifies it's an FQDN
//! let name = Name::from_str("www.example.com.").unwrap();
//!
//! // NOTE: see 'Setup a connection' example above
//! // Send the query and get a message response, see RecordType for all supported options
//! let response: Message = client.query(&name, DNSClass::IN, RecordType::A).unwrap();
//!
//! // Messages are the packets sent between client and server in DNS.
//! //  there are many fields to a Message. It's beyond the scope of these examples
//! //  to explain them. See trust_dns::op::message::Message for more details.
//! //  generally we will be insterested in the Message::answers
//! let answers: &[Record] = response.answers();
//!
//! // Records are generic objects which can contain any data.
//! //  In order to access it we need to first check what type of record it is
//! //  In this case we are interested in A, IPv4 address
//! if let &RData::A(ref ip) = answers[0].rdata() {
//!     assert_eq!(*ip, Ipv4Addr::new(93, 184, 216, 34))
//! } else {
//!     assert!(false, "unexpected result")
//! }
//! ```
//!
//! In the above example we successfully queried for a A record. There are many other types, each can be independenly queried and the associated `trust_dns::rr::record_data::RData` has a variant with the deserialized data for the record stored.
//!
//! ## Dynamic update
//!
//! Currently `trust-dns` supports SIG(0) signed records for authentication and authorization of dynamic DNS updates. It's beyond the scope of these examples to show how to setup SIG(0) authorization on the server. `trust-dns` is known to work with BIND9 and `trust-dns-server`. Expect in the future for TLS to become a potentially better option for authorization with certificate chains. These examples show using SIG(0) for auth, requires OpenSSL. It's beyond the scope of these examples to describe the configuration for the server.

//!
//! ```rust,no_run
//! # extern crate chrono;
//! # extern crate openssl;
//! # extern crate trust_dns;
//!
//! use std::fs::File;
//! use std::io::Read;
//! use std::net::Ipv4Addr;
//! use std::str::FromStr;
//!
//! use chrono::Duration;
//! # #[cfg(feature = "openssl")]
//! use openssl::rsa::Rsa;
//! # use trust_dns::client::Client;
//! # use trust_dns::udp::UdpClientConnection;
//! use trust_dns::client::SyncClient;
//! use trust_dns::rr::{Name, RData, Record, RecordType};
//! use trust_dns::rr::dnssec::{Algorithm, Signer, KeyPair};
//! use trust_dns::op::ResponseCode;
//! use trust_dns::rr::rdata::key::KEY;
//!
//! # #[cfg(feature = "openssl")]
//! # fn main() {
//! # let address = "0.0.0.0:53".parse().unwrap();
//! # let conn = UdpClientConnection::new(address).unwrap();
//!
//! // The format of the key is dependent on the KeyPair type, in this example we're using RSA
//! //  if the key was generated with BIND, the binary in TRust-DNS client lib `dnskey-to-pem`
//! //  can be used to convert this to a pem file
//! let mut pem = File::open("my_private_key.pem").unwrap();
//! let mut pem_buf = Vec::<u8>::new();
//! pem.read_to_end(&mut pem_buf).unwrap();
//!
//! // Create the RSA key
//! let rsa = Rsa::private_key_from_pem(&pem_buf).unwrap();
//! let key = KeyPair::from_rsa(rsa).unwrap();
//!
//! // Create the RData KEY associated with the key. This example uses defaults for all the
//! //  KeyTrust, KeyUsage, UpdateScope, Protocol. Many of these have been deprecated in current
//! //  DNS RFCs, but are still supported by many servers for auth. See auth docs of the remote
//! //  server for help in understanding it's requirements and support of these options.
//! let sig0key = KEY::new(Default::default(),
//!                        Default::default(),
//!                        Default::default(),
//!                        Default::default(),
//!                        Algorithm::RSASHA256,
//!                        key.to_public_bytes().unwrap());
//!
//! // Create the TRust-DNS SIG(0) signing facility. Generally the signer_name is the label
//! //  associated with KEY record in the server.
//! let signer = Signer::sig0(sig0key,
//!                           key,
//!                           Name::from_str("update.example.com.").unwrap());
//!
//! // Create the DNS client, see above for creating a the connection
//! let client = SyncClient::with_signer(conn, signer);
//!
//! // At this point we should have a client capable of sending signed SIG(0) records.
//!
//! // Now we can send updates... let's create a new Record
//! let mut record = Record::with(Name::from_str("new.example.com").unwrap(),
//!                               RecordType::A,
//!                               Duration::minutes(5).num_seconds() as u32);
//! record.set_rdata(RData::A(Ipv4Addr::new(100, 10, 100, 10)));
//!
//! // the server must be authoritative for this zone
//! let origin = Name::from_str("example.com.").unwrap();
//!
//! // Create the record.
//! let result = client.create(record, origin).unwrap();
//! assert_eq!(result.response_code(), ResponseCode::NoError);
//! # }
//! # #[cfg(not(feature = "openssl"))]
//! # fn main() {
//! # }
//! ```
//!
//! *Note*: The dynamic DNS functions defined by TRust-DNS are expressed as atomic operations, but this depends on support of the remote server. For example, the `create` operation shown above, should only succeed if there is no `RecordSet` of the specified type at the specified label. The other update operations are `append`, `compare_and_swap`, `delete_by_rdata`, `delete_rrset`, and `delete_all`. See the documentation for each of these methods on the `Client` trait.


extern crate chrono;
#[cfg(test)]
extern crate data_encoding;
#[macro_use]
extern crate error_chain;
#[macro_use]
extern crate futures;
#[macro_use]
extern crate lazy_static;
#[macro_use]
extern crate log;
#[cfg(feature = "native-tls")]
extern crate native_tls;
#[cfg(feature = "openssl")]
extern crate openssl;
extern crate rand;
#[cfg(feature = "ring")]
extern crate ring;
extern crate rustc_serialize;
extern crate tokio_io;
#[macro_use]
extern crate tokio_core;
#[cfg(feature = "tokio-tls")]
extern crate tokio_tls;
#[cfg(feature = "tokio-openssl")]
extern crate tokio_openssl;
#[cfg(feature = "ring")]
extern crate untrusted;

pub mod client;
pub mod error;
pub mod logger;
pub mod op;
pub mod rr;
pub mod tcp;
#[cfg(all(feature = "tls", feature = "openssl"))]
pub mod tls;
pub mod udp;
pub mod serialize;

#[cfg(test)]
mod tests;

use std::io;
use std::net::SocketAddr;

use futures::sync::mpsc::UnboundedSender;
use futures::Stream;

use op::Message;
use client::ClientStreamHandle;

/// A stream of serialized DNS Messages
pub type BufStream = Stream<Item = (Vec<u8>, SocketAddr), Error = io::Error>;

/// A sender to which serialized DNS Messages can be sent
pub type BufStreamHandle = UnboundedSender<(Vec<u8>, SocketAddr)>;

/// A stream of messsages
pub type MessageStream = Stream<Item = Message, Error = io::Error>;

/// A sender to which a Message can be sent
pub type MessageStreamHandle = UnboundedSender<Message>;

/// A buffering stream bound to a `SocketAddr`
pub struct BufClientStreamHandle {
    name_server: SocketAddr,
    sender: BufStreamHandle,
}

impl BufClientStreamHandle {
    /// Constructs a new Buffered Stream Handle, used for sending data to the DNS peer.
    ///
    /// # Arguments
    ///
    /// * `name_server` - the address of the DNS server
    /// * `sender` - the handle being used to send data to the server
    pub fn new(name_server: SocketAddr, sender: BufStreamHandle) -> Self {
        BufClientStreamHandle {
            name_server: name_server,
            sender: sender,
        }
    }
}

impl ClientStreamHandle for BufClientStreamHandle {
    fn send(&mut self, buffer: Vec<u8>) -> io::Result<()> {
        let name_server: SocketAddr = self.name_server;
        let sender: &mut _ = &mut self.sender;
        sender.unbounded_send((buffer, name_server)).map_err(|_| {
            io::Error::new(io::ErrorKind::Other, "unknown")
        })
    }
}

/// Returns a version as specified in Cargo.toml
pub fn version() -> &'static str {
    env!("CARGO_PKG_VERSION")
}

// TODO switch env_logger and remove this
#[test]
fn enable_logging_for_tests() {
    use log::LogLevel;
    logger::TrustDnsLogger::enable_logging(LogLevel::Debug);
}