_ 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::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         TimeoutAwaitingAddr,
  31         TimeoutAwaitingBlock,
  32         Good,
  33         WasGood,
  34 }
  35
  36 impl AddressState {
  37         pub fn from_num(num: u8) -> Option<AddressState> {
  38                 match num {
  39                         0x0 => Some(AddressState::Untested),
  40                         0x1 => Some(AddressState::LowBlockCount),
  41                         0x2 => Some(AddressState::HighBlockCount),
  42                         0x3 => Some(AddressState::LowVersion),
  43                         0x4 => Some(AddressState::BadVersion),
  44                         0x5 => Some(AddressState::NotFullNode),
  45                         0x6 => Some(AddressState::ProtocolViolation),
  46                         0x7 => Some(AddressState::Timeout),
  47                         0x8 => Some(AddressState::TimeoutDuringRequest),
  48                         0x9 => Some(AddressState::TimeoutAwaitingAddr),
  49                         0xa => Some(AddressState::TimeoutAwaitingBlock),
  50                         0xb => Some(AddressState::Good),
  51                         0xc => Some(AddressState::WasGood),
  52                         _   => None,
  53                 }
  54         }
  55
  56         pub fn to_num(&self) -> u8 {
  57                 match *self {
  58                         AddressState::Untested => 0,
  59                         AddressState::LowBlockCount => 1,
  60                         AddressState::HighBlockCount => 2,
  61                         AddressState::LowVersion => 3,
  62                         AddressState::BadVersion => 4,
  63                         AddressState::NotFullNode => 5,
  64                         AddressState::ProtocolViolation => 6,
  65                         AddressState::Timeout => 7,
  66                         AddressState::TimeoutDuringRequest => 8,
  67                         AddressState::TimeoutAwaitingAddr => 9,
  68                         AddressState::TimeoutAwaitingBlock => 10,
  69                         AddressState::Good => 11,
  70                         AddressState::WasGood => 12,
  71                 }
  72         }
  73
  74         pub fn to_str(&self) -> &'static str {
  75                 match *self {
  76                         AddressState::Untested => "Untested",
  77                         AddressState::LowBlockCount => "Low Block Count",
  78                         AddressState::HighBlockCount => "High Block Count",
  79                         AddressState::LowVersion => "Low Version",
  80                         AddressState::BadVersion => "Bad Version",
  81                         AddressState::NotFullNode => "Not Full Node",
  82                         AddressState::ProtocolViolation => "Protocol Violation",
  83                         AddressState::Timeout => "Timeout",
  84                         AddressState::TimeoutDuringRequest => "Timeout During Request",
  85                         AddressState::TimeoutAwaitingAddr => "Timeout Awaiting Addr",
  86                         AddressState::TimeoutAwaitingBlock => "Timeout Awaiting Block",
  87                         AddressState::Good => "Good",
  88                         AddressState::WasGood => "Was Good",
  89                 }
  90         }
  91
  92         pub const fn get_count() -> u8 {
  93                 13
  94         }
  95 }
  96
  97 #[derive(Hash, PartialEq, Eq)]
  98 pub enum U64Setting {
  99         ConnsPerSec,
 100         RunTimeout,
 101         WasGoodTimeout,
 102         RescanInterval(AddressState),
 103         MinProtocolVersion,
 104 }
 105
 106 #[derive(Hash, PartialEq, Eq)]
 107 pub enum RegexSetting {
 108         SubverRegex,
 109 }
 110
 111 struct Node {
 112         last_update: Instant,
 113         last_good: Instant, // Ignored unless state is Good or WasGood
 114         last_services: u64,
 115         state: AddressState,
 116 }
 117
 118 struct Nodes {
 119         good_node_services: Vec<HashSet<SocketAddr>>,
 120         nodes_to_state: HashMap<SocketAddr, Node>,
 121         state_next_scan: Vec<Vec<(Instant, SocketAddr)>>,
 122 }
 123 struct NodesMutRef<'a> {
 124         good_node_services: &'a mut Vec<HashSet<SocketAddr>>,
 125         nodes_to_state: &'a mut HashMap<SocketAddr, Node>,
 126         state_next_scan: &'a mut Vec<Vec<(Instant, SocketAddr)>>,
 127
 128 }
 129 impl Nodes {
 130         fn borrow_mut<'a>(&'a mut self) -> NodesMutRef<'a> {
 131                 NodesMutRef {
 132                         good_node_services: &mut self.good_node_services,
 133                         nodes_to_state: &mut self.nodes_to_state,
 134                         state_next_scan: &mut self.state_next_scan,
 135                 }
 136         }
 137 }
 138
 139 pub struct Store {
 140         u64_settings: RwLock<HashMap<U64Setting, u64>>,
 141         subver_regex: RwLock<Arc<Regex>>,
 142         nodes: RwLock<Nodes>,
 143         store: String,
 144 }
 145
 146 impl Store {
 147         pub fn new(store: String) -> impl Future<Item=Store, Error=()> {
 148                 let settings_future = File::open(store.clone() + "/settings").and_then(|f| {
 149                         let mut l = BufReader::new(f).lines();
 150                         macro_rules! try_read {
 151                                 ($lines: expr, $ty: ty) => { {
 152                                         match $lines.next() {
 153                                                 Some(line) => match line {
 154                                                         Ok(line) => match line.parse::<$ty>() {
 155                                                                 Ok(res) => res,
 156                                                                 Err(e) => return future::err(std::io::Error::new(std::io::ErrorKind::InvalidData, e)),
 157                                                         },
 158                                                         Err(e) => return future::err(e),
 159                                                 },
 160                                                 None => return future::err(std::io::Error::new(std::io::ErrorKind::UnexpectedEof, "")),
 161                                         }
 162                                 } }
 163                         }
 164                         let mut u64s = HashMap::with_capacity(AddressState::get_count() as usize + 4);
 165                         u64s.insert(U64Setting::ConnsPerSec, try_read!(l, u64));
 166                         u64s.insert(U64Setting::RunTimeout, try_read!(l, u64));
 167                         u64s.insert(U64Setting::WasGoodTimeout, try_read!(l, u64));
 168                         u64s.insert(U64Setting::MinProtocolVersion, try_read!(l, u64));
 169                         u64s.insert(U64Setting::RescanInterval(AddressState::Untested), try_read!(l, u64));
 170                         u64s.insert(U64Setting::RescanInterval(AddressState::LowBlockCount), try_read!(l, u64));
 171                         u64s.insert(U64Setting::RescanInterval(AddressState::HighBlockCount), try_read!(l, u64));
 172                         u64s.insert(U64Setting::RescanInterval(AddressState::LowVersion), try_read!(l, u64));
 173                         u64s.insert(U64Setting::RescanInterval(AddressState::BadVersion), try_read!(l, u64));
 174                         u64s.insert(U64Setting::RescanInterval(AddressState::NotFullNode), try_read!(l, u64));
 175                         u64s.insert(U64Setting::RescanInterval(AddressState::ProtocolViolation), try_read!(l, u64));
 176                         u64s.insert(U64Setting::RescanInterval(AddressState::Timeout), try_read!(l, u64));
 177                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutDuringRequest), try_read!(l, u64));
 178                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutAwaitingAddr), try_read!(l, u64));
 179                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutAwaitingBlock), try_read!(l, u64));
 180                         u64s.insert(U64Setting::RescanInterval(AddressState::Good), try_read!(l, u64));
 181                         u64s.insert(U64Setting::RescanInterval(AddressState::WasGood), try_read!(l, u64));
 182                         future::ok((u64s, try_read!(l, Regex)))
 183                 }).or_else(|_| -> future::FutureResult<(HashMap<U64Setting, u64>, Regex), ()> {
 184                         let mut u64s = HashMap::with_capacity(15);
 185                         u64s.insert(U64Setting::ConnsPerSec, 10);
 186                         u64s.insert(U64Setting::RunTimeout, 120);
 187                         u64s.insert(U64Setting::WasGoodTimeout, 21600);
 188                         u64s.insert(U64Setting::RescanInterval(AddressState::Untested), 0);
 189                         u64s.insert(U64Setting::RescanInterval(AddressState::LowBlockCount), 3600);
 190                         u64s.insert(U64Setting::RescanInterval(AddressState::HighBlockCount), 7200);
 191                         u64s.insert(U64Setting::RescanInterval(AddressState::LowVersion), 21600);
 192                         u64s.insert(U64Setting::RescanInterval(AddressState::BadVersion), 21600);
 193                         u64s.insert(U64Setting::RescanInterval(AddressState::NotFullNode), 86400);
 194                         u64s.insert(U64Setting::RescanInterval(AddressState::ProtocolViolation), 86400);
 195                         u64s.insert(U64Setting::RescanInterval(AddressState::Timeout), 86400);
 196                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutDuringRequest), 21600);
 197                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutAwaitingAddr), 1800);
 198                         u64s.insert(U64Setting::RescanInterval(AddressState::TimeoutAwaitingBlock), 3600);
 199                         u64s.insert(U64Setting::RescanInterval(AddressState::Good), 1800);
 200                         u64s.insert(U64Setting::RescanInterval(AddressState::WasGood), 1800);
 201                         u64s.insert(U64Setting::MinProtocolVersion, 70002);
 202                         future::ok((u64s, Regex::new(".*").unwrap()))
 203                 });
 204
 205                 macro_rules! nodes_uninitd {
 206                         () => { {
 207                                 let mut state_vecs = Vec::with_capacity(AddressState::get_count() as usize);
 208                                 for _ in 0..AddressState::get_count() {
 209                                         state_vecs.push(Vec::new());
 210                                 }
 211                                 let mut good_node_services = Vec::with_capacity(64);
 212                                 for _ in 0..64 {
 213                                         good_node_services.push(HashSet::new());
 214                                 }
 215                                 Nodes {
 216                                         good_node_services,
 217                                         nodes_to_state: HashMap::new(),
 218                                         state_next_scan: state_vecs,
 219                                 }
 220                         } }
 221                 }
 222
 223                 let nodes_future = File::open(store.clone() + "/nodes").and_then(|f| {
 224                         let mut res = nodes_uninitd!();
 225                         let l = BufReader::new(f).lines();
 226                         for line_res in l {
 227                                 let line = match line_res {
 228                                         Ok(l) => l,
 229                                         Err(_) => return future::ok(res),
 230                                 };
 231                                 let mut line_iter = line.split(',');
 232                                 macro_rules! try_read {
 233                                         ($lines: expr, $ty: ty) => { {
 234                                                 match $lines.next() {
 235                                                         Some(line) => match line.parse::<$ty>() {
 236                                                                 Ok(res) => res,
 237                                                                 Err(_) => return future::ok(res),
 238                                                         },
 239                                                         None => return future::ok(res),
 240                                                 }
 241                                         } }
 242                                 }
 243                                 let sockaddr = try_read!(line_iter, SocketAddr);
 244                                 let state = try_read!(line_iter, u8);
 245                                 let last_services = try_read!(line_iter, u64);
 246                                 let node = Node {
 247                                         state: match AddressState::from_num(state) {
 248                                                 Some(v) => v,
 249                                                 None => return future::ok(res),
 250                                         },
 251                                         last_services,
 252                                         last_update: Instant::now(),
 253                                         last_good: Instant::now(),
 254                                 };
 255                                 if node.state == AddressState::Good {
 256                                         for i in 0..64 {
 257                                                 if node.last_services & (1 << i) != 0 {
 258                                                         res.good_node_services[i].insert(sockaddr);
 259                                                 }
 260                                         }
 261                                 }
 262                                 res.state_next_scan[node.state.to_num() as usize].push((Instant::now(), sockaddr));
 263                                 res.nodes_to_state.insert(sockaddr, node);
 264                         }
 265                         future::ok(res)
 266                 }).or_else(|_| -> future::FutureResult<Nodes, ()> {
 267                         future::ok(nodes_uninitd!())
 268                 });
 269                 settings_future.join(nodes_future).and_then(move |((u64_settings, regex), nodes)| {
 270                         future::ok(Store {
 271                                 u64_settings: RwLock::new(u64_settings),
 272                                 subver_regex: RwLock::new(Arc::new(regex)),
 273                                 nodes: RwLock::new(nodes),
 274                                 store,
 275                         })
 276                 })
 277         }
 278
 279         pub fn get_u64(&self, setting: U64Setting) -> u64 {
 280                 *self.u64_settings.read().unwrap().get(&setting).unwrap()
 281         }
 282
 283         pub fn set_u64(&self, setting: U64Setting, value: u64) {
 284                 *self.u64_settings.write().unwrap().get_mut(&setting).unwrap() = value;
 285         }
 286
 287         pub fn get_node_count(&self, state: AddressState) -> usize {
 288                 self.nodes.read().unwrap().state_next_scan[state.to_num() as usize].len()
 289         }
 290
 291         pub fn get_regex(&self, _setting: RegexSetting) -> Arc<Regex> {
 292                 Arc::clone(&*self.subver_regex.read().unwrap())
 293         }
 294
 295         pub fn set_regex(&self, _setting: RegexSetting, value: Regex) {
 296                 *self.subver_regex.write().unwrap() = Arc::new(value);
 297         }
 298
 299         pub fn add_fresh_addrs<I: Iterator<Item=SocketAddr>>(&self, addresses: I) -> u64 {
 300                 let mut res = 0;
 301                 let mut nodes = self.nodes.write().unwrap();
 302                 let cur_time = Instant::now();
 303                 for addr in addresses {
 304                         match nodes.nodes_to_state.entry(addr.clone()) {
 305                                 hash_map::Entry::Vacant(e) => {
 306                                         e.insert(Node {
 307                                                 state: AddressState::Untested,
 308                                                 last_services: 0,
 309                                                 last_update: cur_time,
 310                                                 last_good: cur_time,
 311                                         });
 312                                         nodes.state_next_scan[AddressState::Untested.to_num() as usize].push((cur_time, addr));
 313                                         res += 1;
 314                                 },
 315                                 hash_map::Entry::Occupied(_) => {},
 316                         }
 317                 }
 318                 res
 319         }
 320
 321         pub fn add_fresh_nodes(&self, addresses: &Vec<(u32, Address)>) {
 322                 self.add_fresh_addrs(addresses.iter().filter_map(|(_, addr)| {
 323                         match addr.socket_addr() {
 324                                 Ok(socketaddr) => Some(socketaddr),
 325                                 Err(_) => None, // TODO: Handle onions
 326                         }
 327                 }));
 328         }
 329
 330         pub fn set_node_state(&self, addr: SocketAddr, state: AddressState, services: u64) -> AddressState {
 331                 let mut nodes_lock = self.nodes.write().unwrap();
 332                 let nodes = nodes_lock.borrow_mut();
 333                 let now = Instant::now();
 334
 335                 let state_ref = nodes.nodes_to_state.entry(addr).or_insert(Node {
 336                         state: AddressState::Untested,
 337                         last_services: 0,
 338                         last_update: now,
 339                         last_good: now,
 340                 });
 341                 let ret = state_ref.state;
 342                 if (state_ref.state == AddressState::Good || state_ref.state == AddressState::WasGood)
 343                                 && state != AddressState::Good
 344                                 && state_ref.last_good >= now - Duration::from_secs(self.get_u64(U64Setting::WasGoodTimeout)) {
 345                         state_ref.state = AddressState::WasGood;
 346                         for i in 0..64 {
 347                                 if state_ref.last_services & (1 << i) != 0 {
 348                                         nodes.good_node_services[i].remove(&addr);
 349                                 }
 350                         }
 351                         state_ref.last_services = 0;
 352                         nodes.state_next_scan[AddressState::WasGood.to_num() as usize].push((now, addr));
 353                 } else {
 354                         state_ref.state = state;
 355                         if state == AddressState::Good {
 356                                 for i in 0..64 {
 357                                         if services & (1 << i) != 0 && state_ref.last_services & (1 << i) == 0 {
 358                                                 nodes.good_node_services[i].insert(addr);
 359                                         } else if services & (1 << i) == 0 && state_ref.last_services & (1 << i) != 0 {
 360                                                 nodes.good_node_services[i].remove(&addr);
 361                                         }
 362                                 }
 363                                 state_ref.last_services = services;
 364                                 state_ref.last_good = now;
 365                         }
 366                         nodes.state_next_scan[state.to_num() as usize].push((now, addr));
 367                 }
 368                 state_ref.last_update = now;
 369                 ret
 370         }
 371
 372         pub fn save_data(&'static self) -> impl Future<Item=(), Error=()> {
 373                 let settings_file = self.store.clone() + "/settings";
 374                 let settings_future = File::create(settings_file.clone() + ".tmp").and_then(move |f| {
 375                         let settings_string = format!("{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}",
 376                                 self.get_u64(U64Setting::ConnsPerSec),
 377                                 self.get_u64(U64Setting::RunTimeout),
 378                                 self.get_u64(U64Setting::WasGoodTimeout),
 379                                 self.get_u64(U64Setting::MinProtocolVersion),
 380                                 self.get_u64(U64Setting::RescanInterval(AddressState::Untested)),
 381                                 self.get_u64(U64Setting::RescanInterval(AddressState::LowBlockCount)),
 382                                 self.get_u64(U64Setting::RescanInterval(AddressState::HighBlockCount)),
 383                                 self.get_u64(U64Setting::RescanInterval(AddressState::LowVersion)),
 384                                 self.get_u64(U64Setting::RescanInterval(AddressState::BadVersion)),
 385                                 self.get_u64(U64Setting::RescanInterval(AddressState::NotFullNode)),
 386                                 self.get_u64(U64Setting::RescanInterval(AddressState::ProtocolViolation)),
 387                                 self.get_u64(U64Setting::RescanInterval(AddressState::Timeout)),
 388                                 self.get_u64(U64Setting::RescanInterval(AddressState::TimeoutDuringRequest)),
 389                                 self.get_u64(U64Setting::RescanInterval(AddressState::TimeoutAwaitingAddr)),
 390                                 self.get_u64(U64Setting::RescanInterval(AddressState::TimeoutAwaitingBlock)),
 391                                 self.get_u64(U64Setting::RescanInterval(AddressState::Good)),
 392                                 self.get_u64(U64Setting::RescanInterval(AddressState::WasGood)),
 393                                 self.get_regex(RegexSetting::SubverRegex).as_str());
 394                         write_all(f, settings_string).and_then(|(mut f, _)| {
 395                                 f.poll_sync_all()
 396                         }).and_then(|_| {
 397                                 tokio::fs::rename(settings_file.clone() + ".tmp", settings_file)
 398                         })
 399                 });
 400
 401                 let nodes_file = self.store.clone() + "/nodes";
 402                 let nodes_future = File::create(nodes_file.clone() + ".tmp").and_then(move |f| {
 403                         let mut nodes_buff = String::new();
 404                         {
 405                                 let nodes = self.nodes.read().unwrap();
 406                                 nodes_buff.reserve(nodes.nodes_to_state.len() * 20);
 407                                 for (ref sockaddr, ref node) in nodes.nodes_to_state.iter() {
 408                                         nodes_buff += &sockaddr.to_string();
 409                                         nodes_buff += ",";
 410                                         nodes_buff += &node.state.to_num().to_string();
 411                                         nodes_buff += ",";
 412                                         nodes_buff += &node.last_services.to_string();
 413                                         nodes_buff += "\n";
 414                                 }
 415                         }
 416                         write_all(f, nodes_buff)
 417                 }).and_then(|(mut f, _)| {
 418                         f.poll_sync_all()
 419                 }).and_then(|_| {
 420                         tokio::fs::rename(nodes_file.clone() + ".tmp", nodes_file)
 421                 });
 422
 423                 let dns_file = self.store.clone() + "/nodes.dump";
 424                 let dns_future = File::create(dns_file.clone() + ".tmp").and_then(move |f| {
 425                         let mut dns_buff = String::new();
 426                         {
 427                                 let nodes = self.nodes.read().unwrap();
 428                                 let mut rng = thread_rng();
 429                                 for i in &[1u64, 4, 5, 8, 9, 12, 13, 1024, 1025, 1028, 1029, 1032, 1033, 1036, 1037] {
 430                                         let mut v6_set = Vec::new();
 431                                         let mut v4_set = Vec::new();
 432                                         if i.count_ones() == 1 {
 433                                                 for j in 0..64 {
 434                                                         if i & (1 << j) != 0 {
 435                                                                 let set_ref = &nodes.good_node_services[j];
 436                                                                 v4_set = set_ref.iter().filter(|e| e.is_ipv4() && e.port() == 8333)
 437                                                                         .choose_multiple(&mut rng, 21).iter().map(|e| e.ip()).collect();
 438                                                                 v6_set = set_ref.iter().filter(|e| e.is_ipv6() && e.port() == 8333)
 439                                                                         .choose_multiple(&mut rng, 12).iter().map(|e| e.ip()).collect();
 440                                                                 break;
 441                                                         }
 442                                                 }
 443                                         } else if i.count_ones() == 2 {
 444                                                 let mut first_set = None;
 445                                                 let mut second_set = None;
 446                                                 for j in 0..64 {
 447                                                         if i & (1 << j) != 0 {
 448                                                                 if first_set == None {
 449                                                                         first_set = Some(&nodes.good_node_services[j]);
 450                                                                 } else {
 451                                                                         second_set = Some(&nodes.good_node_services[j]);
 452                                                                         break;
 453                                                                 }
 454                                                         }
 455                                                 }
 456                                                 v4_set = first_set.unwrap().intersection(&second_set.unwrap())
 457                                                         .filter(|e| e.is_ipv4() && e.port() == 8333)
 458                                                         .choose_multiple(&mut rng, 21).iter().map(|e| e.ip()).collect();
 459                                                 v6_set = first_set.unwrap().intersection(&second_set.unwrap())
 460                                                         .filter(|e| e.is_ipv6() && e.port() == 8333)
 461                                                         .choose_multiple(&mut rng, 12).iter().map(|e| e.ip()).collect();
 462                                         } else {
 463                                                 //TODO: Could optimize this one a bit
 464                                                 let mut intersection;
 465                                                 let mut intersection_set_ref = None;
 466                                                 for j in 0..64 {
 467                                                         if i & (1 << j) != 0 {
 468                                                                 if intersection_set_ref == None {
 469                                                                         intersection_set_ref = Some(&nodes.good_node_services[j]);
 470                                                                 } else {
 471                                                                         let new_intersection = intersection_set_ref.unwrap()
 472                                                                                 .intersection(&nodes.good_node_services[j]).map(|e| (*e).clone()).collect();
 473                                                                         intersection = Some(new_intersection);
 474                                                                         intersection_set_ref = Some(intersection.as_ref().unwrap());
 475                                                                 }
 476                                                         }
 477                                                 }
 478                                                 v4_set = intersection_set_ref.unwrap().iter()
 479                                                         .filter(|e| e.is_ipv4() && e.port() == 8333)
 480                                                         .choose_multiple(&mut rng, 21).iter().map(|e| e.ip()).collect();
 481                                                 v6_set = intersection_set_ref.unwrap().iter()
 482                                                         .filter(|e| e.is_ipv6() && e.port() == 8333)
 483                                                         .choose_multiple(&mut rng, 12).iter().map(|e| e.ip()).collect();
 484                                         }
 485                                         for a in v4_set {
 486                                                 dns_buff += &format!("x{:x}.dnsseed\tIN\tA\t{}\n", i, a);
 487                                         }
 488                                         for a in v6_set {
 489                                                 dns_buff += &format!("x{:x}.dnsseed\tIN\tAAAA\t{}\n", i, a);
 490                                         }
 491                                 }
 492                         }
 493                         write_all(f, dns_buff)
 494                 }).and_then(|(mut f, _)| {
 495                         f.poll_sync_all()
 496                 }).and_then(|_| {
 497                         tokio::fs::rename(dns_file.clone() + ".tmp", dns_file)
 498                 });
 499
 500                 settings_future.join3(nodes_future, dns_future).then(|_| { future::ok(()) })
 501         }
 502
 503         pub fn get_next_scan_nodes(&self) -> Vec<SocketAddr> {
 504                 let results = 30 * self.get_u64(U64Setting::ConnsPerSec) as usize;
 505                 let per_bucket_results = results / (AddressState::get_count() as usize);
 506                 let mut res = Vec::with_capacity(results);
 507                 let cur_time = Instant::now();
 508
 509                 {
 510                         let mut nodes = self.nodes.write().unwrap();
 511                         for (idx, state_nodes) in nodes.state_next_scan.iter_mut().enumerate() {
 512                                 let cmp_time = cur_time - Duration::from_secs(self.get_u64(U64Setting::RescanInterval(AddressState::from_num(idx as u8).unwrap())));
 513                                 let split_point = cmp::min(cmp::min(results - res.len(), (per_bucket_results * (idx + 1)) - res.len()),
 514                                                 state_nodes.binary_search_by(|a| a.0.cmp(&cmp_time)).unwrap_or_else(|idx| idx));
 515                                 let mut new_nodes = state_nodes.split_off(split_point);
 516                                 mem::swap(&mut new_nodes, state_nodes);
 517                                 for (_, node) in new_nodes.drain(..) {
 518                                         res.push(node);
 519                                 }
 520                         }
 521                 }
 522                 res.shuffle(&mut thread_rng());
 523                 res
 524         }
 525 }