diff --git a/Cargo.lock b/Cargo.lock index 773742f..0ba2fc1 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -85,6 +85,12 @@ version = "3.19.1" source = "registry+https://github.com/rust-lang/crates.io-index" checksum = "5dd9dc738b7a8311c7ade152424974d8115f2cdad61e8dab8dac9f2362298510" +[[package]] +name = "bytes" +version = "1.11.0" +source = "registry+https://github.com/rust-lang/crates.io-index" +checksum = "b35204fbdc0b3f4446b89fc1ac2cf84a8a68971995d0bf2e925ec7cd960f9cb3" + [[package]] name = "cc" version = "1.2.51" @@ -556,6 +562,7 @@ name = "roowho2" version = "0.1.0" dependencies = [ "anyhow", + "bytes", "chrono", "clap", "nix", @@ -753,9 +760,21 @@ dependencies = [ "mio", "pin-project-lite", "socket2", + "tokio-macros", "windows-sys 0.61.2", ] +[[package]] +name = "tokio-macros" +version = "2.6.0" +source = "registry+https://github.com/rust-lang/crates.io-index" +checksum = "af407857209536a95c8e56f8231ef2c2e2aff839b22e07a1ffcbc617e9db9fa5" +dependencies = [ + "proc-macro2", + "quote", + "syn", +] + [[package]] name = "type-map" version = "0.5.1" diff --git a/Cargo.toml b/Cargo.toml index 84f7492..adec9f0 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -15,10 +15,11 @@ autolib = false [dependencies] anyhow = "1.0.100" +bytes = "1.11.0" chrono = { version = "0.4.42", features = ["serde"] } clap = { version = "4.5.53", features = ["derive"] } nix = { version = "0.30.1", features = ["hostname", "net"] } -tokio = { version = "1.49.0", features = ["net", "rt-multi-thread"] } +tokio = { version = "1.49.0", features = ["macros", "net", "rt-multi-thread"] } # onc-rpc = "0.3.2" # sd-notify = "0.4.5" # serde = { version = "1.0.228", features = ["derive"] } diff --git a/src/bin/roowhod.rs b/src/bin/roowhod.rs index 0b8f907..bac400c 100644 --- a/src/bin/roowhod.rs +++ b/src/bin/roowhod.rs @@ -1,10 +1,41 @@ -fn main() { - println!( - "{:#?}", - roowho2_lib::server::rwhod::generate_rwhod_status_update(), - ); - println!( - "{:#?}", - roowho2_lib::server::rwhod::determine_relevant_interfaces(), - ); +use std::net::SocketAddrV4; + +use anyhow::Context; +use chrono::Timelike; +use roowho2_lib::proto::{Whod, WhodStatusUpdate}; + +const RWHOD_BROADCAST_PORT: u16 = 513; + +#[tokio::main] +async fn main() -> anyhow::Result<()> { + let addr = SocketAddrV4::new(std::net::Ipv4Addr::UNSPECIFIED, RWHOD_BROADCAST_PORT); + let socket = tokio::net::UdpSocket::bind(addr).await?; + socket.set_broadcast(true)?; + + let mut buf = [0u8; Whod::MAX_SIZE]; + loop { + let (len, src) = socket.recv_from(&mut buf).await?; + if len < Whod::HEADER_SIZE { + eprintln!( + "Received too short packet from {src}: {len} bytes (needs to be at least {} bytes)", + Whod::HEADER_SIZE + ); + continue; + } + let result: WhodStatusUpdate = Whod::from_bytes(&buf[..len]) + .context("Failed to parse whod packet")? + .try_into() + .map(|mut status_update: WhodStatusUpdate| { + let timestamp = chrono::Utc::now() + .with_nanosecond(0) + .unwrap_or(chrono::Utc::now()); + status_update.recvtime = Some(timestamp); + status_update + }) + .map_err(|e| anyhow::anyhow!("Invalid whod packet: {}", e))?; + + println!("Received whod packet from {src}:\n{result:#?}"); + + buf = [0u8; Whod::MAX_SIZE]; + } } diff --git a/src/proto/finger_protocol.rs b/src/proto/finger_protocol.rs index e69de29..8b13789 100644 --- a/src/proto/finger_protocol.rs +++ b/src/proto/finger_protocol.rs @@ -0,0 +1 @@ + diff --git a/src/proto/rusers_protocol.rs b/src/proto/rusers_protocol.rs index e69de29..8b13789 100644 --- a/src/proto/rusers_protocol.rs +++ b/src/proto/rusers_protocol.rs @@ -0,0 +1 @@ + diff --git a/src/proto/rwhod_protocol.rs b/src/proto/rwhod_protocol.rs index 93bceba..c5e38bc 100644 --- a/src/proto/rwhod_protocol.rs +++ b/src/proto/rwhod_protocol.rs @@ -1,5 +1,10 @@ use std::array; +use bytes::{Buf, BufMut, BytesMut}; + +/// Classic C struct for utmp data for a single user session. +/// +/// This struct is used in the rwhod protocol by being interpreted as raw bytes to be sent over UDP. #[derive(Debug, Clone)] #[repr(C)] pub struct Outmp { @@ -16,6 +21,9 @@ impl Outmp { pub const MAX_USER_ID_LEN: usize = 8; } +/// Classic C struct for a single user session. +/// +/// This struct is used in the rwhod protocol by being interpreted as raw bytes to be sent over UDP. #[derive(Debug, Clone)] #[repr(C)] pub struct Whoent { @@ -25,6 +33,31 @@ pub struct Whoent { pub we_idle: i32, } +impl Whoent { + pub const SIZE: usize = std::mem::size_of::(); + + fn zeroed() -> Self { + Self { + we_utmp: Outmp { + out_line: [0u8; Outmp::MAX_TTY_NAME_LEN], + out_name: [0u8; Outmp::MAX_USER_ID_LEN], + out_time: 0, + }, + we_idle: 0, + } + } + + fn is_zeroed(&self) -> bool { + self.we_utmp.out_line.iter().all(|&b| b == 0) + && self.we_utmp.out_name.iter().all(|&b| b == 0) + && self.we_utmp.out_time == 0 + && self.we_idle == 0 + } +} + +/// Classic C struct for a rwhod status update. +/// +/// This struct is used in the rwhod protocol by being interpreted as raw bytes to be sent over UDP. #[derive(Debug, Clone)] #[repr(C)] pub struct Whod { @@ -47,7 +80,9 @@ pub struct Whod { } impl Whod { - pub const SIZE: usize = std::mem::size_of::(); + pub const HEADER_SIZE: usize = 1 + 1 + 2 + 4 + 4 + Self::MAX_HOSTNAME_LEN + 4 * 3 + 4; + pub const MAX_SIZE: usize = std::mem::size_of::(); + pub const MAX_HOSTNAME_LEN: usize = 32; pub const MAX_WHOENTRIES: usize = 1024 / std::mem::size_of::(); @@ -56,42 +91,140 @@ impl Whod { // NOTE: there was probably meant to be more packet types, but only status is defined. pub const WHODTYPE_STATUS: u8 = 1; - pub fn to_bytes(&self) -> [u8; std::mem::size_of::()] { - unsafe { std::mem::transmute_copy(self) } + pub fn to_bytes(&self) -> [u8; Whod::MAX_SIZE] { + let mut buf = BytesMut::with_capacity(Whod::MAX_SIZE); + buf.put_u8(self.wd_vers); + buf.put_u8(self.wd_type); + buf.put_slice(&self.wd_pad); + buf.put_i32(self.wd_sendtime); + buf.put_i32(self.wd_recvtime); + buf.put_slice(&self.wd_hostname); + buf.put_i32(self.wd_loadav[0]); + buf.put_i32(self.wd_loadav[1]); + buf.put_i32(self.wd_loadav[2]); + buf.put_i32(self.wd_boottime); + + for whoent in &self.wd_we { + buf.put_slice(&whoent.we_utmp.out_line); + buf.put_slice(&whoent.we_utmp.out_name); + buf.put_i32(whoent.we_utmp.out_time); + buf.put_i32(whoent.we_idle); + } + + // SAFETY: this should never happen, Whod::MAX_SIZE is computed from the struct size + let result = buf + .to_vec() + .try_into() + .expect("Buffer length mismatch, this should never happen"); + + result } - // TODO: we should probably make a safer parser. - pub fn from_bytes(bytes: &[u8; std::mem::size_of::()]) -> Self { - unsafe { std::mem::transmute_copy(bytes) } + pub fn from_bytes(input: &[u8]) -> anyhow::Result { + if input.len() < Self::HEADER_SIZE { + return Err(anyhow::anyhow!( + "Not enough bytes to parse packet header: {} < {}", + input.len(), + Self::HEADER_SIZE + )); + } + + if input.len() > Self::MAX_SIZE { + return Err(anyhow::anyhow!( + "Too many bytes to parse packet: {} > {}", + input.len(), + Self::MAX_SIZE + )); + } + + if (input.len() - Self::HEADER_SIZE) % Whoent::SIZE != 0 { + return Err(anyhow::anyhow!( + "Invalid packet length: {} (not aligned with struct sizes, should be {} + N * {})", + input.len(), + Self::HEADER_SIZE, + Whoent::SIZE, + )); + } + + let mut bytes = bytes::Bytes::copy_from_slice(input); + + let wd_vers = bytes.get_u8(); + let wd_type = bytes.get_u8(); + bytes.advance(2); // skip wd_pad + let wd_sendtime = bytes.get_i32(); + let wd_recvtime = bytes.get_i32(); + let mut wd_hostname = [0u8; Self::MAX_HOSTNAME_LEN]; + bytes.copy_to_slice(&mut wd_hostname); + let wd_loadav = [bytes.get_i32(), bytes.get_i32(), bytes.get_i32()]; + let wd_boottime = bytes.get_i32(); + + debug_assert!(bytes.remaining() + Self::HEADER_SIZE == input.len()); + + let mut wd_we = array::from_fn(|_| Whoent::zeroed()); + + for (byte_chunk, whoent) in bytes.chunks_exact(Whoent::SIZE).zip(wd_we.iter_mut()) { + let mut chunk_bytes = bytes::Bytes::copy_from_slice(byte_chunk); + + let mut out_line = [0u8; Outmp::MAX_TTY_NAME_LEN]; + chunk_bytes.copy_to_slice(&mut out_line); + let mut out_name = [0u8; Outmp::MAX_USER_ID_LEN]; + chunk_bytes.copy_to_slice(&mut out_name); + let out_time = chunk_bytes.get_i32(); + + let we_utmp = Outmp { + out_line, + out_name, + out_time, + }; + let we_idle = chunk_bytes.get_i32(); + + *whoent = Whoent { we_utmp, we_idle }; + } + + Ok(Whod { + wd_vers, + wd_type, + wd_pad: [0u8; 2], + wd_sendtime, + wd_recvtime, + wd_hostname, + wd_loadav, + wd_boottime, + wd_we, + }) } } // ------------------------------------------------ +/// High-level representation of a rwhod status update. +/// +/// This struct is intended for easier use in Rust code, with proper types and dynamic arrays. +/// It can be converted to and from the low-level [`Whod`] struct used for network transmission. #[derive(Debug, Clone)] pub struct WhodStatusUpdate { // NOTE: there is only one defined packet type, so we just omit it here /// Timestamp by sender - sendtime: chrono::DateTime, + pub sendtime: chrono::DateTime, /// Timestamp applied by receiver - recvtime: Option>, + pub recvtime: Option>, /// Name of the host sending the status update (max 32 characters) - hostname: String, + pub hostname: String, /// load average over 5 minutes multiplied by 100 - load_average_5_min: i32, + pub load_average_5_min: i32, /// load average over 10 minutes multiplied by 100 - load_average_10_min: i32, + pub load_average_10_min: i32, /// load average over 15 minutes multiplied by 100 - load_average_15_min: i32, + pub load_average_15_min: i32, /// Which time the system was booted - boot_time: chrono::DateTime, + pub boot_time: chrono::DateTime, /// List of users currently logged in to the host (max 42 entries) - users: Vec, + pub users: Vec, } impl WhodStatusUpdate { @@ -118,19 +251,23 @@ impl WhodStatusUpdate { } } +/// High-level representation of a single user session in a rwhod status update. +/// +/// This struct is intended for easier use in Rust code, with proper types. +/// It can be converted to and from the low-level [`Whoent`] struct used for network transmission. #[derive(Debug, Clone)] pub struct WhodUserEntry { /// TTY name (max 8 characters) - tty: String, + pub tty: String, /// User ID (max 8 characters) - user_id: String, + pub user_id: String, /// Time when the user logged in - login_time: chrono::DateTime, + pub login_time: chrono::DateTime, /// Idle time in seconds - idle_time_seconds: i32, + pub idle_time_seconds: i32, } impl WhodUserEntry { @@ -224,11 +361,13 @@ impl TryFrom for WhodStatusUpdate { format!("Invalid boot time timestamp: {}", value.wd_boottime), )?; - let mut users = Vec::new(); - for whoent in &value.wd_we { - let user_entry = WhodUserEntry::try_from(whoent.clone())?; - users.push(user_entry); - } + let users = value + .wd_we + .iter() + .take_while(|whoent| !whoent.is_zeroed()) + .cloned() + .map(|whoent| WhodUserEntry::try_from(whoent)) + .collect::, String>>()?; Ok(WhodStatusUpdate { sendtime, diff --git a/src/proto/write_protocol.rs b/src/proto/write_protocol.rs index e69de29..8b13789 100644 --- a/src/proto/write_protocol.rs +++ b/src/proto/write_protocol.rs @@ -0,0 +1 @@ +