Align routing table entries to single bytes
[dnsseed-rust] / src / bgp_client.rs
index 10880a6dc835c61965f17d3460eabc6597c7aa24..9038005a3d412aadc075bf26422c38ee32ed494b 100644 (file)
@@ -23,16 +23,50 @@ use crate::printer::{Printer, Stat};
 use crate::timeout_stream::TimeoutStream;
 
 const PATH_SUFFIX_LEN: usize = 3;
-struct Route {
+#[derive(Clone)]
+struct Route { // 32 bytes
        path_suffix: [u32; PATH_SUFFIX_LEN],
        path_len: u32,
        pref: u32,
        med: u32,
 }
 
+// To keep memory tight (and since we dont' need such close alignment), newtype the v4/v6 routing
+// table entries to make sure they are aligned to single bytes.
+
+#[repr(packed)]
+#[derive(PartialEq, Eq, Hash)]
+struct V4Addr {
+       addr: [u8; 4],
+       pfxlen: u8,
+}
+impl From<(Ipv4Addr, u8)> for V4Addr {
+       fn from(p: (Ipv4Addr, u8)) -> Self {
+               Self {
+                       addr: p.0.octets(),
+                       pfxlen: p.1,
+               }
+       }
+}
+
+#[repr(packed)]
+#[derive(PartialEq, Eq, Hash)]
+struct V6Addr {
+       addr: [u8; 16],
+       pfxlen: u8,
+}
+impl From<(Ipv6Addr, u8)> for V6Addr {
+       fn from(p: (Ipv6Addr, u8)) -> Self {
+               Self {
+                       addr: p.0.octets(),
+                       pfxlen: p.1,
+               }
+       }
+}
+
 struct RoutingTable {
-       v4_table: HashMap<(Ipv4Addr, u8), HashMap<u32, Arc<Route>>>,
-       v6_table: HashMap<(Ipv6Addr, u8), HashMap<u32, Arc<Route>>>,
+       v4_table: HashMap<V4Addr, HashMap<u32, Route>>,
+       v6_table: HashMap<V6Addr, HashMap<u32, Route>>,
 }
 
 impl RoutingTable {
@@ -43,29 +77,26 @@ impl RoutingTable {
                }
        }
 
-       fn get_route_attrs(&self, ip: IpAddr) -> Vec<Arc<Route>> {
+       fn get_route_attrs(&self, ip: IpAddr) -> (u8, Vec<&Route>) {
                macro_rules! lookup_res {
                        ($addrty: ty, $addr: expr, $table: expr, $addr_bits: expr) => { {
                                //TODO: Optimize this (probably means making the tables btrees)!
-                               for i in (0..$addr_bits).rev() {
-                                       let mut lookup = $addr.octets();
-                                       for b in 0..(i / 8) {
-                                               lookup[lookup.len() - b - 1] = 0;
-                                       }
-                                       lookup[lookup.len() - (i/8) - 1] &= !(((1u16 << (i % 8)) - 1) as u8);
-                                       let lookup_addr = <$addrty>::from(lookup);
-                                       if let Some(routes) = $table.get(&(lookup_addr, $addr_bits - i as u8)).map(|hm| hm.values()) {
+                               let mut lookup = <$addrty>::from(($addr, $addr_bits));
+                               for i in 0..$addr_bits {
+                                       if let Some(routes) = $table.get(&lookup).map(|hm| hm.values()) {
                                                if routes.len() > 0 {
-                                                       return routes.map(|x| Arc::clone(&x)).collect();
+                                                       return (lookup.pfxlen, routes.collect());
                                                }
                                        }
+                                       lookup.addr[lookup.addr.len() - (i/8) - 1] &= !(1u8 << (i % 8));
+                                       lookup.pfxlen -= 1;
                                }
-                               vec![]
+                               (0, vec![])
                        } }
                }
                match ip {
-                       IpAddr::V4(v4a) => lookup_res!(Ipv4Addr, v4a, self.v4_table, 32),
-                       IpAddr::V6(v6a) => lookup_res!(Ipv6Addr, v6a, self.v6_table, 128)
+                       IpAddr::V4(v4a) => lookup_res!(V4Addr, v4a, self.v4_table, 32),
+                       IpAddr::V6(v6a) => lookup_res!(V6Addr, v6a, self.v6_table, 128)
                }
        }
 
@@ -74,35 +105,35 @@ impl RoutingTable {
                        NLRIEncoding::IP(p) => {
                                let (ip, len) = <(IpAddr, u8)>::from(&p);
                                match ip {
-                                       IpAddr::V4(v4a) => self.v4_table.get_mut(&(v4a, len)).and_then(|hm| hm.remove(&0)),
-                                       IpAddr::V6(v6a) => self.v6_table.get_mut(&(v6a, len)).and_then(|hm| hm.remove(&0)),
+                                       IpAddr::V4(v4a) => self.v4_table.get_mut(&(v4a, len).into()).and_then(|hm| hm.remove(&0)),
+                                       IpAddr::V6(v6a) => self.v6_table.get_mut(&(v6a, len).into()).and_then(|hm| hm.remove(&0)),
                                }
                        },
                        NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
                                let (ip, len) = <(IpAddr, u8)>::from(&p);
                                match ip {
-                                       IpAddr::V4(v4a) => self.v4_table.get_mut(&(v4a, len)).and_then(|hm| hm.remove(&id)),
-                                       IpAddr::V6(v6a) => self.v6_table.get_mut(&(v6a, len)).and_then(|hm| hm.remove(&id)),
+                                       IpAddr::V4(v4a) => self.v4_table.get_mut(&(v4a, len).into()).and_then(|hm| hm.remove(&id)),
+                                       IpAddr::V6(v6a) => self.v6_table.get_mut(&(v6a, len).into()).and_then(|hm| hm.remove(&id)),
                                }
                        },
                        NLRIEncoding::IP_MPLS(_) => None,
                };
        }
 
-       fn announce(&mut self, prefix: NLRIEncoding, route: Arc<Route>) {
+       fn announce(&mut self, prefix: NLRIEncoding, route: Route) {
                match prefix {
                        NLRIEncoding::IP(p) => {
                                let (ip, len) = <(IpAddr, u8)>::from(&p);
                                match ip {
-                                       IpAddr::V4(v4a) => self.v4_table.entry((v4a, len)).or_insert(HashMap::new()).insert(0, route),
-                                       IpAddr::V6(v6a) => self.v6_table.entry((v6a, len)).or_insert(HashMap::new()).insert(0, route),
+                                       IpAddr::V4(v4a) => self.v4_table.entry((v4a, len).into()).or_insert(HashMap::new()).insert(0, route),
+                                       IpAddr::V6(v6a) => self.v6_table.entry((v6a, len).into()).or_insert(HashMap::new()).insert(0, route),
                                }
                        },
                        NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
                                let (ip, len) = <(IpAddr, u8)>::from(&p);
                                match ip {
-                                       IpAddr::V4(v4a) => self.v4_table.entry((v4a, len)).or_insert(HashMap::new()).insert(id, route),
-                                       IpAddr::V6(v6a) => self.v6_table.entry((v6a, len)).or_insert(HashMap::new()).insert(id, route),
+                                       IpAddr::V4(v4a) => self.v4_table.entry((v4a, len).into()).or_insert(HashMap::new()).insert(id, route),
+                                       IpAddr::V6(v6a) => self.v6_table.entry((v6a, len).into()).or_insert(HashMap::new()).insert(id, route),
                                }
                        },
                        NLRIEncoding::IP_MPLS(_) => None,
@@ -177,7 +208,8 @@ pub struct BGPClient {
 }
 impl BGPClient {
        pub fn get_asn(&self, addr: IpAddr) -> u32 {
-               let mut path_vecs = self.routes.lock().unwrap().get_route_attrs(addr).clone();
+               let lock = self.routes.lock().unwrap();
+               let mut path_vecs = lock.get_route_attrs(addr).1;
                if path_vecs.is_empty() { return 0; }
 
                path_vecs.sort_unstable_by(|path_a, path_b| {
@@ -205,6 +237,21 @@ impl BGPClient {
                0
        }
 
+       pub fn get_path(&self, addr: IpAddr) -> (u8, [u32; PATH_SUFFIX_LEN]) {
+               let lock = self.routes.lock().unwrap();
+               let (prefixlen, mut path_vecs) = lock.get_route_attrs(addr);
+               if path_vecs.is_empty() { return (0, [0; PATH_SUFFIX_LEN]); }
+
+               path_vecs.sort_unstable_by(|path_a, path_b| {
+                       path_a.pref.cmp(&path_b.pref)
+                               .then(path_b.path_len.cmp(&path_a.path_len))
+                               .then(path_b.med.cmp(&path_a.med))
+               });
+
+               let primary_route = path_vecs.pop().unwrap();
+               (prefixlen, primary_route.path_suffix)
+       }
+
        pub fn disconnect(&self) {
                self.shutdown.store(true, Ordering::Relaxed);
        }
@@ -302,9 +349,8 @@ impl BGPClient {
                                                                        route_table.withdraw(r);
                                                                }
                                                                if let Some(path) = Self::map_attrs(upd.attributes) {
-                                                                       let path_arc = Arc::new(path);
                                                                        for r in upd.announced_routes {
-                                                                               route_table.announce(r, Arc::clone(&path_arc));
+                                                                               route_table.announce(r, path.clone());
                                                                        }
                                                                }
                                                                printer.set_stat(Stat::V4RoutingTableSize(route_table.v4_table.len()));