basic centralized DNS discovery

1 files changed, 39 insertions, 0 deletions

diff --git a/src/discovery.rs b/src/discovery.rs
new file mode 100644
index 0000000..aef2a60
--- /dev/null
+++ b/src/discovery.rs
@@ -0,0 +1,39 @@
+
+use errors::*;
+use std::net::{IpAddr, SocketAddr};
+use make_discovery_key;
+use data_encoding::HEXLOWER;
+use resolve::{self, DnsConfig, DnsResolver, resolve_host};
+use resolve::record::Srv;
+
+pub fn discover_peers_dns(dat_key: &[u8]) -> Result<Vec<SocketAddr>> {
+
+    let dk = make_discovery_key(dat_key);
+    let dk_hex = HEXLOWER.encode(&dk);
+    let dk_name = format!("{}.dat.local", &dk_hex[0..40]);
+    info!("discovering peers using DNS: {}", dk_name);
+
+    let dns1: Vec<IpAddr> = resolve_host("discovery1.publicbits.org")?.collect();
+    let dns2: Vec<IpAddr> = resolve_host("discovery2.publicbits.org")?.collect();
+
+    let default_config = resolve::default_config()?;
+    let config = DnsConfig {
+        name_servers: vec![
+            SocketAddr::from((dns1[0], 53)),
+            SocketAddr::from((dns2[0], 53))],
+        search: vec!["dat.local".to_string()],
+        n_dots: default_config.n_dots,
+        timeout: default_config.timeout,
+        attempts: default_config.attempts,
+        rotate: true,
+        use_inet6: false,
+    };
+
+    let resolver = DnsResolver::new(config)?;
+
+    let peers: Vec<Srv> = resolver.resolve_record(&dk_name)?;
+    // target (IP addresses) are returned with a trailing period that must be stripped
+    let peers: Vec<SocketAddr> = peers.into_iter().map(|r| format!("{}:{}", &r.target[0..(r.target.len()-1)], r.port).parse().unwrap()).collect();
+    info!("found peers: {:?}", peers);
+    Ok(peers)
+}