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

   1 use std::sync::{Arc, Mutex};
   2 use std::sync::atomic::{AtomicBool, Ordering};
   3 use std::cmp;
   4 use std::collections::HashMap;
   5 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
   6 use std::time::{Duration, Instant};
   7
   8 use bgp_rs::{AFI, SAFI, AddPathDirection, Open, OpenCapability, OpenParameter, NLRIEncoding, PathAttribute};
   9 use bgp_rs::Capabilities;
  10 use bgp_rs::Segment;
  11 use bgp_rs::Message;
  12 use bgp_rs::Reader;
  13
  14 use tokio::prelude::*;
  15 use tokio::codec;
  16 use tokio::codec::Framed;
  17 use tokio::net::TcpStream;
  18 use tokio::timer::Delay;
  19
  20 use futures::sync::mpsc;
  21
  22 use crate::printer::{Printer, Stat};
  23 use crate::timeout_stream::TimeoutStream;
  24
  25 const PATH_SUFFIX_LEN: usize = 3;
  26 struct Route {
  27         path_suffix: [u32; PATH_SUFFIX_LEN],
  28         path_len: u32,
  29         pref: u32,
  30         med: u32,
  31 }
  32
  33 struct RoutingTable {
  34         v4_table: HashMap<(Ipv4Addr, u8), HashMap<u32, Arc<Route>>>,
  35         v6_table: HashMap<(Ipv6Addr, u8), HashMap<u32, Arc<Route>>>,
  36 }
  37
  38 impl RoutingTable {
  39         fn new() -> Self {
  40                 Self {
  41                         v4_table: HashMap::new(),
  42                         v6_table: HashMap::new(),
  43                 }
  44         }
  45
  46         fn get_route_attrs(&self, ip: IpAddr) -> Vec<Arc<Route>> {
  47                 macro_rules! lookup_res {
  48                         ($addrty: ty, $addr: expr, $table: expr, $addr_bits: expr) => { {
  49                                 //TODO: Optimize this (probably means making the tables btrees)!
  50                                 for i in (0..$addr_bits).rev() {
  51                                         let mut lookup = $addr.octets();
  52                                         for b in 0..(i / 8) {
  53                                                 lookup[lookup.len() - b - 1] = 0;
  54                                         }
  55                                         lookup[lookup.len() - (i/8) - 1] &= !(((1u16 << (i % 8)) - 1) as u8);
  56                                         let lookup_addr = <$addrty>::from(lookup);
  57                                         if let Some(routes) = $table.get(&(lookup_addr, $addr_bits - i as u8)).map(|hm| hm.values()) {
  58                                                 if routes.len() > 0 {
  59                                                         return routes.map(|x| Arc::clone(&x)).collect();
  60                                                 }
  61                                         }
  62                                 }
  63                                 vec![]
  64                         } }
  65                 }
  66                 match ip {
  67                         IpAddr::V4(v4a) => lookup_res!(Ipv4Addr, v4a, self.v4_table, 32),
  68                         IpAddr::V6(v6a) => lookup_res!(Ipv6Addr, v6a, self.v6_table, 128)
  69                 }
  70         }
  71
  72         fn withdraw(&mut self, route: NLRIEncoding) {
  73                 match route {
  74                         NLRIEncoding::IP(p) => {
  75                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
  76                                 match ip {
  77                                         IpAddr::V4(v4a) => self.v4_table.get_mut(&(v4a, len)).and_then(|hm| hm.remove(&0)),
  78                                         IpAddr::V6(v6a) => self.v6_table.get_mut(&(v6a, len)).and_then(|hm| hm.remove(&0)),
  79                                 }
  80                         },
  81                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
  82                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
  83                                 match ip {
  84                                         IpAddr::V4(v4a) => self.v4_table.get_mut(&(v4a, len)).and_then(|hm| hm.remove(&id)),
  85                                         IpAddr::V6(v6a) => self.v6_table.get_mut(&(v6a, len)).and_then(|hm| hm.remove(&id)),
  86                                 }
  87                         },
  88                         NLRIEncoding::IP_MPLS(_) => None,
  89                 };
  90         }
  91
  92         fn announce(&mut self, prefix: NLRIEncoding, route: Arc<Route>) {
  93                 match prefix {
  94                         NLRIEncoding::IP(p) => {
  95                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
  96                                 match ip {
  97                                         IpAddr::V4(v4a) => self.v4_table.entry((v4a, len)).or_insert(HashMap::new()).insert(0, route),
  98                                         IpAddr::V6(v6a) => self.v6_table.entry((v6a, len)).or_insert(HashMap::new()).insert(0, route),
  99                                 }
 100                         },
 101                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 102                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 103                                 match ip {
 104                                         IpAddr::V4(v4a) => self.v4_table.entry((v4a, len)).or_insert(HashMap::new()).insert(id, route),
 105                                         IpAddr::V6(v6a) => self.v6_table.entry((v6a, len)).or_insert(HashMap::new()).insert(id, route),
 106                                 }
 107                         },
 108                         NLRIEncoding::IP_MPLS(_) => None,
 109                 };
 110         }
 111 }
 112
 113 struct BytesCoder<'a>(&'a mut bytes::BytesMut);
 114 impl<'a> std::io::Write for BytesCoder<'a> {
 115         fn write(&mut self, b: &[u8]) -> Result<usize, std::io::Error> {
 116                 self.0.extend_from_slice(&b);
 117                 Ok(b.len())
 118         }
 119         fn flush(&mut self) -> Result<(), std::io::Error> {
 120                 Ok(())
 121         }
 122 }
 123 struct BytesDecoder<'a> {
 124         buf: &'a mut bytes::BytesMut,
 125         pos: usize,
 126 }
 127 impl<'a> std::io::Read for BytesDecoder<'a> {
 128         fn read(&mut self, b: &mut [u8]) -> Result<usize, std::io::Error> {
 129                 let copy_len = cmp::min(b.len(), self.buf.len() - self.pos);
 130                 b[..copy_len].copy_from_slice(&self.buf[self.pos..self.pos + copy_len]);
 131                 self.pos += copy_len;
 132                 Ok(copy_len)
 133         }
 134 }
 135
 136 struct MsgCoder<'a>(&'a Printer);
 137 impl<'a> codec::Decoder for MsgCoder<'a> {
 138         type Item = Message;
 139         type Error = std::io::Error;
 140
 141         fn decode(&mut self, bytes: &mut bytes::BytesMut) -> Result<Option<Message>, std::io::Error> {
 142                 let mut decoder = BytesDecoder {
 143                         buf: bytes,
 144                         pos: 0
 145                 };
 146                 match (Reader {
 147                         stream: &mut decoder,
 148                         capabilities: Capabilities {
 149                                 FOUR_OCTET_ASN_SUPPORT: true,
 150                                 EXTENDED_PATH_NLRI_SUPPORT: true,
 151                         }
 152                 }).read() {
 153                         Ok((_header, msg)) => {
 154                                 decoder.buf.advance(decoder.pos);
 155                                 Ok(Some(msg))
 156                         },
 157                         Err(e) => match e.kind() {
 158                                 std::io::ErrorKind::UnexpectedEof => Ok(None),
 159                                 _ => Err(e),
 160                         },
 161                 }
 162         }
 163 }
 164 impl<'a> codec::Encoder for MsgCoder<'a> {
 165         type Item = Message;
 166         type Error = std::io::Error;
 167
 168         fn encode(&mut self, msg: Message, res: &mut bytes::BytesMut) -> Result<(), std::io::Error> {
 169                 msg.write(&mut BytesCoder(res))?;
 170                 Ok(())
 171         }
 172 }
 173
 174 pub struct BGPClient {
 175         routes: Mutex<RoutingTable>,
 176         shutdown: AtomicBool,
 177 }
 178 impl BGPClient {
 179         pub fn get_asn(&self, addr: IpAddr) -> u32 {
 180                 let mut path_vecs = self.routes.lock().unwrap().get_route_attrs(addr).clone();
 181                 if path_vecs.is_empty() { return 0; }
 182
 183                 path_vecs.sort_unstable_by(|path_a, path_b| {
 184                         path_a.pref.cmp(&path_b.pref)
 185                                 .then(path_b.path_len.cmp(&path_a.path_len))
 186                                 .then(path_b.med.cmp(&path_a.med))
 187                 });
 188
 189                 let primary_route = path_vecs.pop().unwrap();
 190                 'asn_candidates: for asn in primary_route.path_suffix.iter().rev() {
 191                         if *asn == 0 { continue 'asn_candidates; }
 192                         for secondary_route in path_vecs.iter() {
 193                                 if !secondary_route.path_suffix.contains(asn) {
 194                                         continue 'asn_candidates;
 195                                 }
 196                         }
 197                         return *asn;
 198                 }
 199
 200                 for asn in primary_route.path_suffix.iter().rev() {
 201                         if *asn != 0 {
 202                                 return *asn;
 203                         }
 204                 }
 205                 0
 206         }
 207
 208         pub fn disconnect(&self) {
 209                 self.shutdown.store(true, Ordering::Relaxed);
 210         }
 211
 212         fn map_attrs(mut attrs: Vec<PathAttribute>) -> Option<Route> {
 213                 let mut as4_path = None;
 214                 let mut as_path = None;
 215                 let mut pref = 100;
 216                 let mut med = 0;
 217                 for attr in attrs.drain(..) {
 218                         match attr {
 219                                 PathAttribute::AS4_PATH(path) => as4_path = Some(path),
 220                                 PathAttribute::AS_PATH(path) => as_path = Some(path),
 221                                 PathAttribute::LOCAL_PREF(p) => pref = p,
 222                                 PathAttribute::MULTI_EXIT_DISC(m) => med = m,
 223                                 _ => {},
 224                         }
 225                 }
 226                 if let Some(mut aspath) = as4_path.or(as_path) {
 227                         let mut pathvec = Vec::new();
 228                         for seg in aspath.segments.drain(..) {
 229                                 match seg {
 230                                         Segment::AS_SEQUENCE(mut asn) => pathvec.append(&mut asn),
 231                                         Segment::AS_SET(_) => {}, // Ignore sets for now, they're not that common anyway
 232                                 }
 233                         }
 234                         let path_len = pathvec.len() as u32;
 235                         pathvec.dedup_by(|a, b| (*a).eq(b)); // Drop prepends, cause we don't care in this case
 236
 237                         let mut path_suffix = [0; PATH_SUFFIX_LEN];
 238                         for (idx, asn) in pathvec.iter().rev().enumerate() {
 239                                 path_suffix[PATH_SUFFIX_LEN - idx - 1] = *asn;
 240                                 if idx == PATH_SUFFIX_LEN - 1 { break; }
 241                         }
 242
 243                         return Some(Route {
 244                                 path_suffix,
 245                                 path_len,
 246                                 pref,
 247                                 med,
 248                         })
 249                 } else { None }
 250         }
 251
 252         fn connect_given_client(addr: SocketAddr, timeout: Duration, printer: &'static Printer, client: Arc<BGPClient>) {
 253                 tokio::spawn(Delay::new(Instant::now() + timeout / 4).then(move |_| {
 254                         let connect_timeout = Delay::new(Instant::now() + timeout.clone()).then(|_| {
 255                                 future::err(std::io::Error::new(std::io::ErrorKind::TimedOut, "timeout reached"))
 256                         });
 257                         let client_reconn = Arc::clone(&client);
 258                         TcpStream::connect(&addr).select(connect_timeout)
 259                                 .or_else(move |_| {
 260                                         Delay::new(Instant::now() + timeout / 2).then(|_| {
 261                                                 future::err(())
 262                                         })
 263                                 }).and_then(move |stream| {
 264                                         let (write, read) = Framed::new(stream.0, MsgCoder(printer)).split();
 265                                         let (mut sender, receiver) = mpsc::channel(10); // We never really should send more than 10 messages unless they're dumb
 266                                         tokio::spawn(write.sink_map_err(|_| { () }).send_all(receiver)
 267                                                 .then(|_| {
 268                                                         future::err(())
 269                                                 }));
 270                                         let _ = sender.try_send(Message::Open(Open {
 271                                                 version: 4,
 272                                                 peer_asn: 23456,
 273                                                 hold_timer: timeout.as_secs() as u16,
 274                                                 identifier: 0x453b1215, // 69.59.18.21
 275                                                 parameters: vec![OpenParameter::Capabilities(vec![
 276                                                         OpenCapability::MultiProtocol((AFI::IPV4, SAFI::Unicast)),
 277                                                         OpenCapability::MultiProtocol((AFI::IPV6, SAFI::Unicast)),
 278                                                         OpenCapability::FourByteASN(397444),
 279                                                         OpenCapability::RouteRefresh,
 280                                                         OpenCapability::AddPath(vec![
 281                                                                 (AFI::IPV4, SAFI::Unicast, AddPathDirection::ReceivePaths),
 282                                                                 (AFI::IPV6, SAFI::Unicast, AddPathDirection::ReceivePaths)]),
 283                                                 ])]
 284                                         }));
 285                                         TimeoutStream::new_persistent(read, timeout).for_each(move |bgp_msg| {
 286                                                 if client.shutdown.load(Ordering::Relaxed) {
 287                                                         return future::err(std::io::Error::new(std::io::ErrorKind::Other, "Shutting Down"));
 288                                                 }
 289                                                 match bgp_msg {
 290                                                         Message::Open(_) => {
 291                                                                 client.routes.lock().unwrap().v4_table.clear();
 292                                                                 client.routes.lock().unwrap().v6_table.clear();
 293                                                                 printer.add_line("Connected to BGP route provider".to_string(), false);
 294                                                         },
 295                                                         Message::KeepAlive => {
 296                                                                 let _ = sender.try_send(Message::KeepAlive);
 297                                                         },
 298                                                         Message::Update(mut upd) => {
 299                                                                 upd.normalize();
 300                                                                 let mut route_table = client.routes.lock().unwrap();
 301                                                                 for r in upd.withdrawn_routes {
 302                                                                         route_table.withdraw(r);
 303                                                                 }
 304                                                                 if let Some(path) = Self::map_attrs(upd.attributes) {
 305                                                                         let path_arc = Arc::new(path);
 306                                                                         for r in upd.announced_routes {
 307                                                                                 route_table.announce(r, Arc::clone(&path_arc));
 308                                                                         }
 309                                                                 }
 310                                                                 printer.set_stat(Stat::V4RoutingTableSize(route_table.v4_table.len()));
 311                                                                 printer.set_stat(Stat::V6RoutingTableSize(route_table.v6_table.len()));
 312                                                         },
 313                                                         _ => {}
 314                                                 }
 315                                                 future::ok(())
 316                                         }).or_else(move |e| {
 317                                                 printer.add_line(format!("Got error from BGP stream: {:?}", e), true);
 318                                                 future::ok(())
 319                                         })
 320                                 }).then(move |_| {
 321                                         if !client_reconn.shutdown.load(Ordering::Relaxed) {
 322                                                 BGPClient::connect_given_client(addr, timeout, printer, client_reconn);
 323                                         }
 324                                         future::ok(())
 325                                 })
 326                         })
 327                 );
 328         }
 329
 330         pub fn new(addr: SocketAddr, timeout: Duration, printer: &'static Printer) -> Arc<BGPClient> {
 331                 let client = Arc::new(BGPClient {
 332                         routes: Mutex::new(RoutingTable::new()),
 333                         shutdown: AtomicBool::new(false),
 334                 });
 335                 BGPClient::connect_given_client(addr, timeout, printer, Arc::clone(&client));
 336                 client
 337         }
 338 }