Add a torrent announce subcommand (#510)

This command makes use of a partially-implemented UDP tracker client to
announce an infohash and list the response.

type: added

Cargo.toml

@@ -14,7 +14,7 @@ default-run = "imdl"
 
 [features]
 default = []
-bench   = ["rand"]
+bench   = []
 
 [dependencies]
 ansi_term         = "0.12.0"
@@ -29,6 +29,7 @@ lexiclean         = "0.0.1"
 libc              = "0.2.0"
 log               = "0.4.8"
 md5               = "0.7.0"
+rand              = "0.7.3"
 open              = "1.4.0"
 pretty_assertions = "0.6.0"
 pretty_env_logger = "0.4.0"
@@ -65,10 +66,6 @@ features = ["default", "wrap_help"]
 version = "2.1.1"
 features = ["serde"]
 
-[dependencies.rand]
-version  = "0.7.3"
-optional = true
-
 [dev-dependencies]
 criterion = "0.3.0"
 temptree  = "0.0.0"

bin/gen/config.yaml

@@ -11,6 +11,10 @@ examples:
   text:    "BitTorrent metainfo related functionality is under the `torrent` subcommand:"
   code:    "imdl torrent --help"
 
+- command: imdl torrent announce
+  text:    "Announce the infohash to all trackers in the supplied `.torrent` file, and print the peer lists that come back:"
+  code:    "imdl torrent announce --input foo.torrent"
+
 - command: imdl torrent create
   text:    "Intermodal can be used to create `.torrent` files:"
   code:    "imdl torrent create --input foo"

src/common.rs

@@ -12,14 +12,15 @@ pub(crate) use std::{
   hash::Hash,
   io::{self, BufRead, BufReader, Cursor, Read, Write},
   iter::{self, Sum},
+  net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, ToSocketAddrs, UdpSocket},
   num::{ParseFloatError, ParseIntError, TryFromIntError},
   ops::{AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign},
   path::{self, Path, PathBuf},
   process::ExitStatus,
   str::{self, FromStr},
   string::FromUtf8Error,
   sync::Once,
-  time::{SystemTime, SystemTimeError},
+  time::{Duration, SystemTime, SystemTimeError},
   usize,
 };
 
@@ -31,6 +32,7 @@ pub(crate) use ignore::WalkBuilder;
 pub(crate) use indicatif::{ProgressBar, ProgressStyle};
 pub(crate) use lexiclean::Lexiclean;
 pub(crate) use libc::EXIT_FAILURE;
+pub(crate) use rand::Rng;
 pub(crate) use regex::{Regex, RegexSet};
 pub(crate) use serde::{de::Error as _, Deserialize, Deserializer, Serialize, Serializer};
 pub(crate) use serde_hex::SerHex;
@@ -52,7 +54,7 @@ pub(crate) use url::{Host, Url};
 pub(crate) use log::trace;
 
 // modules
-pub(crate) use crate::{consts, error, host_port_parse_error, magnet_link_parse_error};
+pub(crate) use crate::{consts, error, host_port_parse_error, magnet_link_parse_error, tracker};
 
 // functions
 pub(crate) use crate::xor_args::xor_args;

src/error.rs

@@ -54,6 +54,8 @@ pub(crate) enum Error {
     source: bendy::serde::Error,
     input: InputTarget,
   },
+  #[snafu(display("Torrent metainfo does not specify any usable trackers"))]
+  MetainfoMissingTrackers,
   #[snafu(display("Failed to serialize torrent metainfo: {}", source))]
   MetainfoSerialize { source: bendy::serde::Error },
   #[snafu(display("Failed to decode metainfo bencode from {}: {}", input, error))]
@@ -136,6 +138,43 @@ pub(crate) enum Error {
   SymlinkRoot { root: PathBuf },
   #[snafu(display("Failed to retrieve system time: {}", source))]
   SystemTime { source: SystemTimeError },
+  #[snafu(display("Compact peer list is not the expected length"))]
+  TrackerCompactPeerList,
+  #[snafu(display("Tracker exchange to `udp://{}` timed out.", tracker_addr))]
+  TrackerExchange { tracker_addr: SocketAddr },
+  #[snafu(display(
+    "Cannot connect to tracker `{}`: URL does not specify a valid host port",
+    tracker_url
+  ))]
+  TrackerHostPort {
+    source: HostPortParseError,
+    tracker_url: Url,
+  },
+  #[snafu(display("Tracker client cannot announce without a connection id"))]
+  TrackerNoConnectionId,
+  #[snafu(display("Tracker resolved to no useable addresses"))]
+  TrackerNoHosts,
+  #[snafu(display("Malformed response from tracker"))]
+  TrackerResponse,
+  #[snafu(display("Response from tracker has wrong length: got {}; want {}", got, want))]
+  TrackerResponseLength { want: usize, got: usize },
+  #[snafu(display("Tracker failed to send datagram: {}", source))]
+  TrackerSend { source: io::Error },
+  #[snafu(display("Failed to resolve socket addrs: {}", source))]
+  TrackerSocketAddrs { source: io::Error },
+  #[snafu(display(
+    "Cannot connect to tracker `{}`: only UDP trackers are supported",
+    tracker_url
+  ))]
+  TrackerUdpOnly { tracker_url: Url },
+  #[snafu(display("Failed to bind to UDP socket: {}", source))]
+  UdpSocketBind { source: io::Error },
+  #[snafu(display("Failed to connect to `udp://{}`: {}", addr, source))]
+  UdpSocketConnect { addr: SocketAddr, source: io::Error },
+  #[snafu(display("Failed to get local UDP socket address: {}", source))]
+  UdpSocketLocalAddress { source: io::Error },
+  #[snafu(display("Failed to set read timeout: {}", source))]
+  UdpSocketReadTimeout { source: io::Error },
   #[snafu(display(
     "Feature `{}` cannot be used without passing the `--unstable` flag",
     feature

src/host_port.rs

@@ -57,6 +57,42 @@ impl Display for HostPort {
   }
 }
 
+impl TryFrom<&Url> for HostPort {
+  type Error = HostPortParseError;
+
+  fn try_from(url: &Url) -> Result<Self, HostPortParseError> {
+    match (url.host(), url.port()) {
+      (Some(host), Some(port)) => Ok(HostPort {
+        host: host.to_owned(),
+        port,
+      }),
+      (Some(_), None) => Err(HostPortParseError::PortMissing {
+        text: url.as_str().to_owned(),
+      }),
+      (None, Some(_)) => Err(HostPortParseError::HostMissing {
+        text: url.as_str().to_owned(),
+      }),
+      (None, None) => Err(HostPortParseError::HostPortMissing {
+        text: url.as_str().to_owned(),
+      }),
+    }
+  }
+}
+
+impl ToSocketAddrs for HostPort {
+  type Iter = std::vec::IntoIter<SocketAddr>;
+
+  fn to_socket_addrs(&self) -> io::Result<Self::Iter> {
+    let address = match &self.host {
+      Host::Domain(domain) => return (domain.clone(), self.port).to_socket_addrs(),
+      Host::Ipv4(address) => IpAddr::V4(*address),
+      Host::Ipv6(address) => IpAddr::V6(*address),
+    };
+
+    Ok(vec![SocketAddr::new(address, self.port)].into_iter())
+  }
+}
+
 #[derive(Serialize, Deserialize)]
 struct Tuple(String, u16);
 
@@ -156,4 +192,18 @@ mod tests {
       "l39:1234:5678:9abc:def0:1234:5678:9abc:def0i65000ee",
     );
   }
+
+  #[test]
+  fn test_from_url() {
+    let url = Url::parse("udp://imdl.io:12345").unwrap();
+    let host_port = HostPort::try_from(&url).unwrap();
+    assert_eq!(host_port.host, Host::Domain("imdl.io".into()));
+    assert_eq!(host_port.port, 12345);
+  }
+
+  #[test]
+  fn test_from_url_no_port() {
+    let url = Url::parse("udp://imdl.io").unwrap();
+    assert!(HostPort::try_from(&url).is_err());
+  }
 }

src/host_port_parse_error.rs

@@ -12,4 +12,8 @@ pub(crate) enum HostPortParseError {
   Port { text: String, source: ParseIntError },
   #[snafu(display("Port missing: `{}`", text))]
   PortMissing { text: String },
+  #[snafu(display("Host missing: `{}`", text))]
+  HostMissing { text: String },
+  #[snafu(display("Host and port missing: `{}`", text))]
+  HostPortMissing { text: String },
 }

src/infohash.rs

@@ -62,6 +62,12 @@ impl From<Sha1Digest> for Infohash {
   }
 }
 
+impl From<Infohash> for [u8; 20] {
+  fn from(infohash: Infohash) -> Self {
+    infohash.inner.bytes()
+  }
+}
+
 impl From<Infohash> for Sha1Digest {
   fn from(infohash: Infohash) -> Sha1Digest {
     infohash.inner

src/lib.rs

@@ -89,6 +89,7 @@ mod style;
 mod subcommand;
 mod table;
 mod torrent_summary;
+mod tracker;
 mod use_color;
 mod verifier;
 mod walker;

src/subcommand/torrent.rs

@@ -1,5 +1,6 @@
 use crate::common::*;
 
+mod announce;
 mod create;
 mod link;
 mod piece_length;
@@ -14,6 +15,7 @@ mod verify;
   about("Subcommands related to the BitTorrent protocol.")
 )]
 pub(crate) enum Torrent {
+  Announce(announce::Announce),
   Create(create::Create),
   Link(link::Link),
   #[structopt(alias = "piece-size")]
@@ -26,6 +28,7 @@ pub(crate) enum Torrent {
 impl Torrent {
   pub(crate) fn run(self, env: &mut Env, options: &Options) -> Result<(), Error> {
     match self {
+      Self::Announce(announce) => announce.run(env),
       Self::Create(create) => create.run(env, options),
       Self::Link(link) => link.run(env),
       Self::PieceLength(piece_length) => piece_length.run(env),