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