basic centralized DNS discovery

3 files changed, 61 insertions, 0 deletions

diff --git a/src/bin/geniza-net.rs b/src/bin/geniza-net.rs
index dd80c4f..e6fa448 100644
--- a/src/bin/geniza-net.rs
+++ b/src/bin/geniza-net.rs
@@ -56,6 +56,11 @@ fn run() -> Result<()> {
                 .arg_from_usage("<dat_key> 'dat key (public key) to convert (in hex)'"),
         )
         .subcommand(
+            SubCommand::with_name("discover-dns")
+                .about("Does a centralized DNS lookup for peers with the given key")
+                .arg_from_usage("<dat_key> 'dat key (public key) to lookup"),
+        )
+        .subcommand(
             SubCommand::with_name("naive-clone")
                 .about("Pulls a drive from a single (known) peer, using a naive algorithm")
                 .arg(Arg::with_name("dat-dir")
@@ -126,6 +131,18 @@ fn run() -> Result<()> {
             }
             println!(".dat.local");
         }
+        ("discover-dns", Some(subm)) => {
+            let dat_key = subm.value_of("dat_key").unwrap();
+            let key_bytes = parse_dat_key(&dat_key)?;
+            let peers = discover_peers_dns(&key_bytes)?;
+            if peers.len() == 0 {
+                println!("No peers found!");
+            } else {
+                for p in peers {
+                    println!("{}", p);
+                }
+            }
+        }
         ("naive-clone", Some(subm)) => {
             let host_port = subm.value_of("host_port").unwrap();
             let dat_key = subm.value_of("dat_key").unwrap();
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)
+}
diff --git a/src/lib.rs b/src/lib.rs
index 10139d3..bc62d78 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -24,6 +24,8 @@ extern crate protobuf;
 extern crate rand;
 extern crate sodiumoxide;
 extern crate bit_field;
+extern crate resolve;
+extern crate data_encoding;
 
 #[cfg(test)]
 extern crate tempdir;
@@ -35,6 +37,7 @@ mod errors {
     error_chain! {
         foreign_links { Fmt(::std::fmt::Error);
                         Io(::std::io::Error) #[cfg(unix)];
+                        AddrParseError(::std::net::AddrParseError);
                         Protobuf(::protobuf::ProtobufError); }
     }
 }
@@ -55,6 +58,8 @@ pub mod network_msgs;
 pub mod metadata_msgs;
 mod node;
 pub use node::*;
+mod discovery;
+pub use discovery::*;
 
 // Shared functions
 use crypto::digest::Digest;