_ Git - dnsseed-rust/blob - src/datastore.rs

   1 use std::{cmp, mem};
   2 use std::collections::{HashSet, HashMap, hash_map};
   3 use std::sync::{Arc, RwLock};
   4 use std::net::{IpAddr, SocketAddr};
   5 use std::time::{Duration, Instant};
   6 use std::io::{BufRead, BufReader};
   7
   8 use bitcoin::network::address::Address;
   9
  10 use rand::thread_rng;
  11 use rand::seq::{SliceRandom, IteratorRandom};
  12
  13 use tokio::prelude::*;
  14 use tokio::fs::File;
  15 use tokio::io::write_all;
  16
  17 use regex::Regex;
  18
  19 #[derive(Clone, Copy, Hash, PartialEq, Eq)]
  20 pub enum AddressState {
  21         Untested,
  22         LowBlockCount,
  23         HighBlockCount,
  24         LowVersion,
  25         BadVersion,
  26         NotFullNode,
  27         ProtocolViolation,
  28         Timeout,
  29         TimeoutDuringRequest,
  30         TimeoutAwaitingPong,
  31         TimeoutAwaitingAddr,
  32         TimeoutAwaitingBlock,
  33         Good,
  34         WasGood,
  35         EvilNode,
  36 }
  37
  38 impl AddressState {
  39         pub fn from_num(num: u8) -> Option<AddressState> {
  40                 match num {
  41                         0x0 => Some(AddressState::Untested),
  42                         0x1 => Some(AddressState::LowBlockCount),
  43                         0x2 => Some(AddressState::HighBlockCount),
  44                         0x3 => Some(AddressState::LowVersion),
  45                         0x4 => Some(AddressState::BadVersion),
  46                         0x5 => Some(AddressState::NotFullNode),
  47                         0x6 => Some(AddressState::ProtocolViolation),
  48                         0x7 => Some(AddressState::Timeout),
  49                         0x8 => Some(AddressState::TimeoutDuringRequest),
  50                         0x9 => Some(AddressState::TimeoutAwaitingPong),
  51                         0xa => Some(AddressState::TimeoutAwaitingAddr),
  52                         0xb => Some(AddressState::TimeoutAwaitingBlock),
  53                         0xc => Some(AddressState::Good),
  54                         0xd => Some(AddressState::WasGood),
  55                         0xe => Some(AddressState::EvilNode),
  56                         _   => None,
  57                 }
  58         }
  59
  60         pub fn to_num(&self) -> u8 {
  61                 match *self {
  62                         AddressState::Untested => 0,
  63                         AddressState::LowBlockCount => 1,
  64                         AddressState::HighBlockCount => 2,
  65                         AddressState::LowVersion => 3,
  66                         AddressState::BadVersion => 4,
  67                         AddressState::NotFullNode => 5,
  68                         AddressState::ProtocolViolation => 6,
  69                         AddressState::Timeout => 7,
  70                         AddressState::TimeoutDuringRequest => 8,
  71                         AddressState::TimeoutAwaitingPong => 9,
  72                         AddressState::TimeoutAwaitingAddr => 10,
  73                         AddressState::TimeoutAwaitingBlock => 11,
  74                         AddressState::Good => 12,
  75                         AddressState::WasGood => 13,
  76                         AddressState::EvilNode => 14,
  77                 }
  78         }
  79
  80         pub fn to_str(&self) -> &'static str {
  81                 match *self {
  82                         AddressState::Untested => "Untested",
  83                         AddressState::LowBlockCount => "Low Block Count",
  84                         AddressState::HighBlockCount => "High Block Count",
  85                         AddressState::LowVersion => "Low Version",
  86                         AddressState::BadVersion => "Bad Version",
  87                         AddressState::NotFullNode => "Not Full Node",
  88                         AddressState::ProtocolViolation => "Protocol Violation",
  89                         AddressState::Timeout => "Timeout",
  90                         AddressState::TimeoutDuringRequest => "Timeout During Request",
  91                         AddressState::TimeoutAwaitingPong => "Timeout Awaiting Pong",
  92                         AddressState::TimeoutAwaitingAddr => "Timeout Awaiting Addr",
  93                         AddressState::TimeoutAwaitingBlock => "Timeout Awaiting Block",
  94                         AddressState::Good => "Good",
  95                         AddressState::WasGood => "Was Good",
  96                         AddressState::EvilNode => "Evil Node",
  97                 }
  98         }
  99
 100         pub const fn get_count() -> u8 {
 101                 15
 102         }
 103 }
 104
 105 #[derive(Hash, PartialEq, Eq)]
 106 pub enum U64Setting {
 107         ConnsPerSec,
 108         RunTimeout,
 109         WasGoodTimeout,
 110         RescanInterval(AddressState),
 111         MinProtocolVersion,
 112 }
 113
 114 #[derive(Hash, PartialEq, Eq)]
 115 pub enum RegexSetting {
 116         SubverRegex,
 117 }
 118
 119 struct Node {
 120         last_update: Instant,
 121         last_good: Instant, // Ignored unless state is Good or WasGood
 122         last_services: u64,
 123         state: AddressState,
 124 }
 125
 126 struct Nodes {
 127         good_node_services: Vec<HashSet<SocketAddr>>,
 128         nodes_to_state: HashMap<SocketAddr, Node>,
 129         state_next_scan: Vec<Vec<(Instant, SocketAddr)>>,
 130 }
 131 struct NodesMutRef<'a> {
 132         good_node_services: &'a mut Vec<HashSet<SocketAddr>>,
 133         nodes_to_state: &'a mut HashMap<SocketAddr, Node>,
 134         state_next_scan: &'a mut Vec<Vec<(Instant, SocketAddr)>>,
 135
 136 }
 137 impl Nodes {
 138         fn borrow_mut<'a>(&'a mut self) -> NodesMutRef<'a> {
 139                 NodesMutRef {
 140                         good_node_services: &mut self.good_node_services,
 141                         nodes_to_state: &mut self.nodes_to_state,
 142                         state_next_scan: &mut self.state_next_scan,
 143                 }
 144         }
 145 }
 146
 147 pub struct Store {
 148         u64_settings: RwLock<HashMap<U64Setting, u64>>,
 149         subver_regex: RwLock<Arc<Regex>>,
 150         nodes: RwLock<Nodes>,
 151         store: String,
 152 }
 153
 154 impl Store {
 155         pub fn new(store: String) -> impl Future<Item=Store, Error=()> {
 156                 let settings_future = File::open(store.clone() + "/settings").and_then(|f| {
 157                         let mut l = BufReader::new(f).lines();
 158                         macro_rules! try_read {
 159                                 ($lines: expr, $ty: ty) => { {
 160                                         match $lines.next() {
 161                                                 Some(line) => match line {
 162                                                         Ok(line) => match line.parse::<$ty>() {
 163                                                                 Ok(res) => res,
 164                                                                 Err(e) => return future::err(std::io::Error::new(std::io::ErrorKind::InvalidData, e)),
 165                                                         },
 166                                                         Err(e) => return future::err(e),
 167                                                 },
 168                                                 None => return future::err(std::io::Error::new(std::io::ErrorKind::UnexpectedEof, "")),
 169                                         }
 170                                 } }
 171                         }
 172                         let mut u64s = HashMap::with_capacity(AddressState::get_count() as usize + 4);
 173                         u64s.insert(U64Setting::ConnsPerSec, try_read!(l, u64));
 174                         u64s.insert(U64Setting::RunTimeout, try_read!(l, u64));
 175                         u64s.insert(U64Setting::WasGoodTimeout, try_read!(l, u64));
 176                         u64s.insert(U64Setting::MinProtocolVersion, try_read!(l, u64));
 177                         u64s.insert(U64Setting::RescanInterval(AddressState::Untested), try_read!(l, u64));
 178                         u64s.insert(U64Setting::RescanInterval(AddressState::LowBlockCount), try_read!(l, u64));
 179                         u64s.insert(U64Setting::RescanInterval(AddressState::HighBlockCount), try_read!(l, u64));
 180                         u64s.insert(U64Setting::RescanInterval(AddressState::LowVersion), try_read!(l, u64));
 181                         u64s.insert(U64Setting::RescanInterval(AddressState::BadVersion), try_read!(l, u64));
 182                         u64s.insert(U64Setting::RescanInterval(AddressState::NotFullNode), try_read!(l, u64));
 183                         u64s.insert(U64Setting::RescanInterval(AddressState::ProtocolViolation), try_read!(l, u64));
 184                         u64s.insert(U64Setting::RescanInterval(AddressState::Timeout), try_read!(l, u64));
 185                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutDuringRequest), try_read!(l, u64));
 186                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutAwaitingPong), try_read!(l, u64));
 187                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutAwaitingAddr), try_read!(l, u64));
 188                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutAwaitingBlock), try_read!(l, u64));
 189                         u64s.insert(U64Setting::RescanInterval(AddressState::Good), try_read!(l, u64));
 190                         u64s.insert(U64Setting::RescanInterval(AddressState::WasGood), try_read!(l, u64));
 191                         u64s.insert(U64Setting::RescanInterval(AddressState::EvilNode), try_read!(l, u64));
 192                         future::ok((u64s, try_read!(l, Regex)))
 193                 }).or_else(|_| -> future::FutureResult<(HashMap<U64Setting, u64>, Regex), ()> {
 194                         let mut u64s = HashMap::with_capacity(15);
 195                         u64s.insert(U64Setting::ConnsPerSec, 10);
 196                         u64s.insert(U64Setting::RunTimeout, 120);
 197                         u64s.insert(U64Setting::WasGoodTimeout, 21600);
 198                         u64s.insert(U64Setting::RescanInterval(AddressState::Untested), 0);
 199                         u64s.insert(U64Setting::RescanInterval(AddressState::LowBlockCount), 3600);
 200                         u64s.insert(U64Setting::RescanInterval(AddressState::HighBlockCount), 7200);
 201                         u64s.insert(U64Setting::RescanInterval(AddressState::LowVersion), 21600);
 202                         u64s.insert(U64Setting::RescanInterval(AddressState::BadVersion), 21600);
 203                         u64s.insert(U64Setting::RescanInterval(AddressState::NotFullNode), 86400);
 204                         u64s.insert(U64Setting::RescanInterval(AddressState::ProtocolViolation), 86400);
 205                         u64s.insert(U64Setting::RescanInterval(AddressState::Timeout), 86400);
 206                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutDuringRequest), 21600);
 207                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutAwaitingPong), 3600);
 208                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutAwaitingAddr), 1800);
 209                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutAwaitingBlock), 3600);
 210                         u64s.insert(U64Setting::RescanInterval(AddressState::Good), 1800);
 211                         u64s.insert(U64Setting::RescanInterval(AddressState::WasGood), 1800);
 212                         u64s.insert(U64Setting::RescanInterval(AddressState::EvilNode), 315360000);
 213                         u64s.insert(U64Setting::MinProtocolVersion, 70002);
 214                         future::ok((u64s, Regex::new(".*").unwrap()))
 215                 });
 216
 217                 macro_rules! nodes_uninitd {
 218                         () => { {
 219                                 let mut state_vecs = Vec::with_capacity(AddressState::get_count() as usize);
 220                                 for _ in 0..AddressState::get_count() {
 221                                         state_vecs.push(Vec::new());
 222                                 }
 223                                 let mut good_node_services = Vec::with_capacity(64);
 224                                 for _ in 0..64 {
 225                                         good_node_services.push(HashSet::new());
 226                                 }
 227                                 Nodes {
 228                                         good_node_services,
 229                                         nodes_to_state: HashMap::new(),
 230                                         state_next_scan: state_vecs,
 231                                 }
 232                         } }
 233                 }
 234
 235                 let nodes_future = File::open(store.clone() + "/nodes").and_then(|f| {
 236                         let mut res = nodes_uninitd!();
 237                         let l = BufReader::new(f).lines();
 238                         for line_res in l {
 239                                 let line = match line_res {
 240                                         Ok(l) => l,
 241                                         Err(_) => return future::ok(res),
 242                                 };
 243                                 let mut line_iter = line.split(',');
 244                                 macro_rules! try_read {
 245                                         ($lines: expr, $ty: ty) => { {
 246                                                 match $lines.next() {
 247                                                         Some(line) => match line.parse::<$ty>() {
 248                                                                 Ok(res) => res,
 249                                                                 Err(_) => return future::ok(res),
 250                                                         },
 251                                                         None => return future::ok(res),
 252                                                 }
 253                                         } }
 254                                 }
 255                                 let sockaddr = try_read!(line_iter, SocketAddr);
 256                                 let state = try_read!(line_iter, u8);
 257                                 let last_services = try_read!(line_iter, u64);
 258                                 let node = Node {
 259                                         state: match AddressState::from_num(state) {
 260                                                 Some(v) => v,
 261                                                 None => return future::ok(res),
 262                                         },
 263                                         last_services,
 264                                         last_update: Instant::now(),
 265                                         last_good: Instant::now(),
 266                                 };
 267                                 if node.state == AddressState::Good {
 268                                         for i in 0..64 {
 269                                                 if node.last_services & (1 << i) != 0 {
 270                                                         res.good_node_services[i].insert(sockaddr);
 271                                                 }
 272                                         }
 273                                 }
 274                                 res.state_next_scan[node.state.to_num() as usize].push((Instant::now(), sockaddr));
 275                                 res.nodes_to_state.insert(sockaddr, node);
 276                         }
 277                         future::ok(res)
 278                 }).or_else(|_| -> future::FutureResult<Nodes, ()> {
 279                         future::ok(nodes_uninitd!())
 280                 });
 281                 settings_future.join(nodes_future).and_then(move |((u64_settings, regex), nodes)| {
 282                         future::ok(Store {
 283                                 u64_settings: RwLock::new(u64_settings),
 284                                 subver_regex: RwLock::new(Arc::new(regex)),
 285                                 nodes: RwLock::new(nodes),
 286                                 store,
 287                         })
 288                 })
 289         }
 290
 291         pub fn get_u64(&self, setting: U64Setting) -> u64 {
 292                 *self.u64_settings.read().unwrap().get(&setting).unwrap()
 293         }
 294
 295         pub fn set_u64(&self, setting: U64Setting, value: u64) {
 296                 *self.u64_settings.write().unwrap().get_mut(&setting).unwrap() = value;
 297         }
 298
 299         pub fn get_node_count(&self, state: AddressState) -> usize {
 300                 self.nodes.read().unwrap().state_next_scan[state.to_num() as usize].len()
 301         }
 302
 303         pub fn get_regex(&self, _setting: RegexSetting) -> Arc<Regex> {
 304                 Arc::clone(&*self.subver_regex.read().unwrap())
 305         }
 306
 307         pub fn set_regex(&self, _setting: RegexSetting, value: Regex) {
 308                 *self.subver_regex.write().unwrap() = Arc::new(value);
 309         }
 310
 311         pub fn add_fresh_addrs<I: Iterator<Item=SocketAddr>>(&self, addresses: I) -> u64 {
 312                 let mut res = 0;
 313                 let mut nodes = self.nodes.write().unwrap();
 314                 let cur_time = Instant::now();
 315                 for addr in addresses {
 316                         match nodes.nodes_to_state.entry(addr.clone()) {
 317                                 hash_map::Entry::Vacant(e) => {
 318                                         e.insert(Node {
 319                                                 state: AddressState::Untested,
 320                                                 last_services: 0,
 321                                                 last_update: cur_time,
 322                                                 last_good: cur_time,
 323                                         });
 324                                         nodes.state_next_scan[AddressState::Untested.to_num() as usize].push((cur_time, addr));
 325                                         res += 1;
 326                                 },
 327                                 hash_map::Entry::Occupied(_) => {},
 328                         }
 329                 }
 330                 res
 331         }
 332
 333         pub fn add_fresh_nodes(&self, addresses: &Vec<(u32, Address)>) {
 334                 self.add_fresh_addrs(addresses.iter().filter_map(|(_, addr)| {
 335                         match addr.socket_addr() {
 336                                 Ok(socketaddr) => Some(socketaddr),
 337                                 Err(_) => None, // TODO: Handle onions
 338                         }
 339                 }));
 340         }
 341
 342         pub fn set_node_state(&self, addr: SocketAddr, state: AddressState, services: u64) -> AddressState {
 343                 let mut nodes_lock = self.nodes.write().unwrap();
 344                 let nodes = nodes_lock.borrow_mut();
 345                 let now = Instant::now();
 346
 347                 let state_ref = nodes.nodes_to_state.entry(addr).or_insert(Node {
 348                         state: AddressState::Untested,
 349                         last_services: 0,
 350                         last_update: now,
 351                         last_good: now,
 352                 });
 353                 let ret = state_ref.state;
 354                 if (state_ref.state == AddressState::Good || state_ref.state == AddressState::WasGood)
 355                                 && state != AddressState::Good
 356                                 && state_ref.last_good >= now - Duration::from_secs(self.get_u64(U64Setting::WasGoodTimeout)) {
 357                         state_ref.state = AddressState::WasGood;
 358                         for i in 0..64 {
 359                                 if state_ref.last_services & (1 << i) != 0 {
 360                                         nodes.good_node_services[i].remove(&addr);
 361                                 }
 362                         }
 363                         state_ref.last_services = 0;
 364                         nodes.state_next_scan[AddressState::WasGood.to_num() as usize].push((now, addr));
 365                 } else {
 366                         state_ref.state = state;
 367                         if state == AddressState::Good {
 368                                 for i in 0..64 {
 369                                         if services & (1 << i) != 0 && state_ref.last_services & (1 << i) == 0 {
 370                                                 nodes.good_node_services[i].insert(addr);
 371                                         } else if services & (1 << i) == 0 && state_ref.last_services & (1 << i) != 0 {
 372                                                 nodes.good_node_services[i].remove(&addr);
 373                                         }
 374                                 }
 375                                 state_ref.last_services = services;
 376                                 state_ref.last_good = now;
 377                         }
 378                         nodes.state_next_scan[state.to_num() as usize].push((now, addr));
 379                 }
 380                 state_ref.last_update = now;
 381                 ret
 382         }
 383
 384         pub fn save_data(&'static self) -> impl Future<Item=(), Error=()> {
 385                 let settings_file = self.store.clone() + "/settings";
 386                 let settings_future = File::create(settings_file.clone() + ".tmp").and_then(move |f| {
 387                         let settings_string = format!("{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}",
 388                                 self.get_u64(U64Setting::ConnsPerSec),
 389                                 self.get_u64(U64Setting::RunTimeout),
 390                                 self.get_u64(U64Setting::WasGoodTimeout),
 391                                 self.get_u64(U64Setting::MinProtocolVersion),
 392                                 self.get_u64(U64Setting::RescanInterval(AddressState::Untested)),
 393                                 self.get_u64(U64Setting::RescanInterval(AddressState::LowBlockCount)),
 394                                 self.get_u64(U64Setting::RescanInterval(AddressState::HighBlockCount)),
 395                                 self.get_u64(U64Setting::RescanInterval(AddressState::LowVersion)),
 396                                 self.get_u64(U64Setting::RescanInterval(AddressState::BadVersion)),
 397                                 self.get_u64(U64Setting::RescanInterval(AddressState::NotFullNode)),
 398                                 self.get_u64(U64Setting::RescanInterval(AddressState::ProtocolViolation)),
 399                                 self.get_u64(U64Setting::RescanInterval(AddressState::Timeout)),
 400                                 self.get_u64(U64Setting::RescanInterval(AddressState::TimeoutDuringRequest)),
 401                                 self.get_u64(U64Setting::RescanInterval(AddressState::TimeoutAwaitingPong)),
 402                                 self.get_u64(U64Setting::RescanInterval(AddressState::TimeoutAwaitingAddr)),
 403                                 self.get_u64(U64Setting::RescanInterval(AddressState::TimeoutAwaitingBlock)),
 404                                 self.get_u64(U64Setting::RescanInterval(AddressState::Good)),
 405                                 self.get_u64(U64Setting::RescanInterval(AddressState::WasGood)),
 406                                 self.get_u64(U64Setting::RescanInterval(AddressState::EvilNode)),
 407                                 self.get_regex(RegexSetting::SubverRegex).as_str());
 408                         write_all(f, settings_string).and_then(|(mut f, _)| {
 409                                 f.poll_sync_all()
 410                         }).and_then(|_| {
 411                                 tokio::fs::rename(settings_file.clone() + ".tmp", settings_file)
 412                         })
 413                 });
 414
 415                 let nodes_file = self.store.clone() + "/nodes";
 416                 let nodes_future = File::create(nodes_file.clone() + ".tmp").and_then(move |f| {
 417                         let mut nodes_buff = String::new();
 418                         {
 419                                 let nodes = self.nodes.read().unwrap();
 420                                 nodes_buff.reserve(nodes.nodes_to_state.len() * 20);
 421                                 for (ref sockaddr, ref node) in nodes.nodes_to_state.iter() {
 422                                         nodes_buff += &sockaddr.to_string();
 423                                         nodes_buff += ",";
 424                                         nodes_buff += &node.state.to_num().to_string();
 425                                         nodes_buff += ",";
 426                                         nodes_buff += &node.last_services.to_string();
 427                                         nodes_buff += "\n";
 428                                 }
 429                         }
 430                         write_all(f, nodes_buff)
 431                 }).and_then(|(mut f, _)| {
 432                         f.poll_sync_all()
 433                 }).and_then(|_| {
 434                         tokio::fs::rename(nodes_file.clone() + ".tmp", nodes_file)
 435                 });
 436
 437                 settings_future.join(nodes_future).then(|_| { future::ok(()) })
 438         }
 439
 440         pub fn write_dns(&'static self) -> impl Future<Item=(), Error=()> {
 441                 let dns_file = self.store.clone() + "/nodes.dump";
 442                 File::create(dns_file.clone() + ".tmp").and_then(move |f| {
 443                         let mut dns_buff = String::new();
 444                         {
 445                                 let mut rng = thread_rng();
 446                                 for i in &[1u64, 4, 5, 8, 9, 12, 13, 1024, 1025, 1028, 1029, 1032, 1033, 1036, 1037] {
 447                                         let mut v6_set: Vec<IpAddr> = Vec::new();
 448                                         let mut v4_set: Vec<IpAddr> = Vec::new();
 449                                         {
 450                                                 let nodes = self.nodes.read().unwrap();
 451                                                 if i.count_ones() == 1 {
 452                                                         for j in 0..64 {
 453                                                                 if i & (1 << j) != 0 {
 454                                                                         let set_ref = &nodes.good_node_services[j];
 455                                                                         v4_set = set_ref.iter().filter(|e| e.is_ipv4() && e.port() == 8333).map(|e| e.ip()).collect();
 456                                                                         v6_set = set_ref.iter().filter(|e| e.is_ipv6() && e.port() == 8333).map(|e| e.ip()).collect();
 457                                                                         break;
 458                                                                 }
 459                                                         }
 460                                                 } else if i.count_ones() == 2 {
 461                                                         let mut first_set = None;
 462                                                         let mut second_set = None;
 463                                                         for j in 0..64 {
 464                                                                 if i & (1 << j) != 0 {
 465                                                                         if first_set == None {
 466                                                                                 first_set = Some(&nodes.good_node_services[j]);
 467                                                                         } else {
 468                                                                                 second_set = Some(&nodes.good_node_services[j]);
 469                                                                                 break;
 470                                                                         }
 471                                                                 }
 472                                                         }
 473                                                         v4_set = first_set.unwrap().intersection(&second_set.unwrap())
 474                                                                 .filter(|e| e.is_ipv4() && e.port() == 8333).map(|e| e.ip()).collect();
 475                                                         v6_set = first_set.unwrap().intersection(&second_set.unwrap())
 476                                                                 .filter(|e| e.is_ipv6() && e.port() == 8333).map(|e| e.ip()).collect();
 477                                                 } else {
 478                                                         //TODO: Could optimize this one a bit
 479                                                         let mut intersection;
 480                                                         let mut intersection_set_ref = None;
 481                                                         for j in 0..64 {
 482                                                                 if i & (1 << j) != 0 {
 483                                                                         if intersection_set_ref == None {
 484                                                                                 intersection_set_ref = Some(&nodes.good_node_services[j]);
 485                                                                         } else {
 486                                                                                 let new_intersection = intersection_set_ref.unwrap()
 487                                                                                         .intersection(&nodes.good_node_services[j]).map(|e| (*e).clone()).collect();
 488                                                                                 intersection = Some(new_intersection);
 489                                                                                 intersection_set_ref = Some(intersection.as_ref().unwrap());
 490                                                                         }
 491                                                                 }
 492                                                         }
 493                                                         v4_set = intersection_set_ref.unwrap().iter()
 494                                                                 .filter(|e| e.is_ipv4() && e.port() == 8333).map(|e| e.ip()).collect();
 495                                                         v6_set = intersection_set_ref.unwrap().iter()
 496                                                                 .filter(|e| e.is_ipv6() && e.port() == 8333).map(|e| e.ip()).collect();
 497                                                 }
 498                                         }
 499                                         for a in v4_set.iter().choose_multiple(&mut rng, 21) {
 500                                                 dns_buff += &format!("x{:x}.dnsseed\tIN\tA\t{}\n", i, a);
 501                                         }
 502                                         for a in v6_set.iter().choose_multiple(&mut rng, 12) {
 503                                                 dns_buff += &format!("x{:x}.dnsseed\tIN\tAAAA\t{}\n", i, a);
 504                                         }
 505                                 }
 506                         }
 507                         write_all(f, dns_buff)
 508                 }).and_then(|(mut f, _)| {
 509                         f.poll_sync_all()
 510                 }).and_then(|_| {
 511                         tokio::fs::rename(dns_file.clone() + ".tmp", dns_file)
 512                 }).then(|_| { future::ok(()) })
 513         }
 514
 515         pub fn get_next_scan_nodes(&self) -> Vec<SocketAddr> {
 516                 let results = 30 * self.get_u64(U64Setting::ConnsPerSec) as usize;
 517                 let per_bucket_results = results / (AddressState::get_count() as usize);
 518                 let mut res = Vec::with_capacity(results);
 519                 let cur_time = Instant::now();
 520
 521                 {
 522                         let mut nodes = self.nodes.write().unwrap();
 523                         for (idx, state_nodes) in nodes.state_next_scan.iter_mut().enumerate() {
 524                                 let cmp_time = cur_time - Duration::from_secs(self.get_u64(U64Setting::RescanInterval(AddressState::from_num(idx as u8).unwrap())));
 525                                 let split_point = cmp::min(cmp::min(results - res.len(), (per_bucket_results * (idx + 1)) - res.len()),
 526                                                 state_nodes.binary_search_by(|a| a.0.cmp(&cmp_time)).unwrap_or_else(|idx| idx));
 527                                 let mut new_nodes = state_nodes.split_off(split_point);
 528                                 mem::swap(&mut new_nodes, state_nodes);
 529                                 for (_, node) in new_nodes.drain(..) {
 530                                         res.push(node);
 531                                 }
 532                         }
 533                 }
 534                 res.shuffle(&mut thread_rng());
 535                 res
 536         }
 537 }