implement shutdown

src/config.rs

@@ -7,7 +7,8 @@ use std::{
 };
 
 use crate::{
-    error::{WError, WResult}, mac::{Device, Mac, Nick},
+    error::{WError, WResult},
+    mac::{Device, Mac, Nick},
 };
 
 pub struct Config {
@@ -47,7 +48,6 @@ impl Config {
                     &nick.name
                 )))
                 .map(|mac| mac.clone()),
-            Device::IpV4(_) => todo!(),
         }
     }
 

src/daemon.rs

@@ -65,9 +65,9 @@ fn read_command(stream: &mut TcpStream) -> WResult<String> {
     Ok(command)
 }
 
+// TODO: Use DBus to send a message to systemd instead of spawning a new process
 fn build_shutdown_cmd() -> Command {
     let mut cmd = Command::new("systemctl");
-    cmd.arg("-k");
     cmd.arg("poweroff");
 
     cmd

src/error.rs

@@ -13,8 +13,11 @@ pub enum WError {
     ConfigDirInitError(String),
     ConfigFileFormatError(String),
     UdpSocketBindError(std::io::Error),
+    TcpSocketBindError(std::io::Error),
+    TcpSocketWriteError(std::io::Error),
     InvalidCommandString(String),
     FfiFailed(String),
+    MacNotInNetwork(String),
 
     DaemonSocketBindError(std::io::Error),
     DaemonConnectionReadError(std::io::Error),
@@ -34,8 +37,11 @@ impl Display for WError {
             WError::ConfigDirInitError(s) => format!("{}", s),
             WError::ConfigFileFormatError(s) => format!("{}", s),
             WError::UdpSocketBindError(e) => format!("Couldn't bind and send udp packet because {}", e),
+            WError::TcpSocketBindError(e) => format!("Couldn't bind and send tcp packet because {}", e),
+            WError::TcpSocketWriteError(e) => format!("Couldn't write to TcpStream because {}", e),
             WError::InvalidCommandString(s) => format!("Command string '{}' is unknown", s),
             WError::FfiFailed(s) => format!("FFI invocation failed {}", s),
+            WError::MacNotInNetwork(s) => format!("Mac {} was not found in the local network", s),
 
             WError::DaemonCommandError(s) => format!("Failed to execute command {}", s),
             WError::DaemonCommandExecutionError(output) => format!(

src/mac.rs

@@ -40,6 +40,10 @@ impl Mac {
             magic_bytes[start..start + 6].copy_from_slice(&self.mac_bytes);
         }
     }
+
+    pub(crate) fn is_same(&self, other: &Mac) -> bool {
+        self.mac_bytes == other.mac_bytes
+    }
 }
 
 impl Display for Mac {
@@ -68,16 +72,9 @@ impl Nick {
     }
 }
 
-pub(crate) struct IpV4 {
-    original_string: String,
-    ip: [u8; 4],
-    port: u32,
-}
-
 pub(crate) enum Device {
     Mac(Mac),
     Nick(Nick),
-    IpV4(IpV4),
 }
 
 impl Device {

src/main.rs

@@ -1,4 +1,3 @@
-mod arp;
 mod config;
 mod daemon;
 mod error;

src/netif.rs

@@ -1,11 +1,196 @@
 use std::collections::HashMap;
 use std::ffi::{CStr, c_uchar};
+use std::fs;
+use std::mem::replace;
 use std::net::Ipv4Addr;
 use std::os::raw::{c_char, c_int, c_uint, c_ushort, c_void};
+use std::str::FromStr;
 
 use crate::error::{WError, WResult};
 use crate::mac::Mac;
 
+pub struct LocalNetwork {
+    // 192.168.0.7
+    pub source_ip_hint: Ipv4Addr,
+    // 192.168.0.255 = source_ip_hint | ~netmask
+    pub subnet_broadcast: Ipv4Addr,
+}
+
+pub fn get_local_networks() -> WResult<Vec<LocalNetwork>> {
+    let mut networks = Vec::new();
+    let interfaces = get_network_interfaces()?;
+    let mut unique_broadcast_addresses = Vec::new();
+    for i in &interfaces {
+        if unique_broadcast_addresses.contains(&i.broadcast) {
+            continue;
+        }
+
+        // man systemd.net-naming-scheme
+        // Only broadcast to local network
+        let iname = &i.name;
+        if iname.starts_with("en") || iname.starts_with("wl") || iname.starts_with("eth") {
+            unique_broadcast_addresses.push(i.broadcast);
+            let local_network = LocalNetwork {
+                source_ip_hint: i.ip,
+                subnet_broadcast: i.broadcast,
+            };
+            networks.push(local_network);
+        }
+    }
+
+    Ok(networks)
+}
+
+pub fn find_ip_with_mac(mac: Mac) -> WResult<Ipv4Addr> {
+    let Some(ip) = find_ip_from_arp(&mac, "/proc/net/arp") else {
+        return Err(WError::MacNotInNetwork(mac.to_string()));
+    };
+
+    Ok(ip)
+}
+
+fn find_ip_from_arp(mac: &Mac, arp_file_name: &str) -> Option<Ipv4Addr> {
+    let Ok(contents) = fs::read(arp_file_name) else {
+        eprintln!("ARP file not found at {}", arp_file_name);
+        return None;
+    };
+
+    // 0 = save word
+    // 1 = skip whitespace
+    // 4 = skip line
+    // Start with 4 to skip header
+    let mut state = 4;
+    let mut line: Vec<String> = Vec::new();
+    let mut current = Vec::new();
+    for b in contents {
+        if state == 4 {
+            if b != b'\n' {
+                continue;
+            }
+
+            if line.len() >= 4 {
+                let this_mac = Mac::create(&line[3]).expect(&format!(
+                    "arp file is corrupted, tried to pase {} as a mac address",
+                    line[3]
+                ));
+
+                if this_mac.is_same(&mac) {
+                    return Some(Ipv4Addr::from_str(&line[0]).expect(&format!(
+                        "arp file is corrupted, tried to parse {} as an ip address",
+                        line[0]
+                    )));
+                }
+            }
+
+            line = Vec::new();
+            current = Vec::new();
+            state = 0;
+            continue;
+        }
+
+        if state == 0 {
+            if b != b' ' {
+                current.push(b);
+                continue;
+            }
+
+            let c = replace(&mut current, Vec::new());
+            let word = String::from_utf8_lossy(&c).to_string();
+            line.push(word);
+
+            if line.len() == 4 {
+                state = 4;
+            } else {
+                state = 1;
+            }
+
+            continue;
+        }
+
+        if state == 1 {
+            if b == b' ' {
+                continue;
+            }
+
+            current.push(b);
+            state = 0;
+            continue;
+        }
+    }
+
+    None
+}
+
+// via libc getifaddr //
+fn get_network_interfaces() -> WResult<Vec<NetworkInterface>> {
+    let mut network_addresses = HashMap::new();
+    let mut link_addresses = HashMap::new();
+    let mut addrs: *mut IfAddrs = std::ptr::null_mut();
+
+    unsafe {
+        let stat = getifaddrs(&mut addrs);
+        if stat != 0 {
+            return Err(WError::FfiFailed(format!(
+                "Failed to call libc:getifaddrs, returned {}",
+                stat
+            )));
+        }
+
+        let mut cur = addrs;
+        while !cur.is_null() {
+            let ifa = &*cur;
+            let name = CStr::from_ptr(ifa.ifa_name).to_string_lossy().to_string();
+            if ifa.ifa_addr.is_null() {
+                cur = ifa.ifa_next;
+                continue;
+            }
+
+            let family = (*ifa.ifa_addr).sa_family;
+            if family == AF_INET {
+                let sa_ip = ifa.ifa_addr as *const SockAddrIn;
+                let sa_netmask = ifa.ifa_netmask as *const SockAddrIn;
+                let ip = read_sa_ip(sa_ip);
+                let netmask = read_sa_ip(sa_netmask);
+                let broadcast = calculate_broadcast_address(ip, netmask);
+                let network_address = NetworkAddress {
+                    source_ip_hint: ip,
+                    broadcast,
+                };
+
+                network_addresses.insert(name, network_address);
+            } else if family == AF_PACKET {
+                let sock_addr_ll = ifa.ifa_addr as *const SockAddrLl;
+                let mac = read_sa_ll(sock_addr_ll);
+
+                let link_address = LinkAddress { mac };
+
+                link_addresses.insert(name, link_address);
+            }
+
+            cur = ifa.ifa_next;
+        }
+
+        freeifaddrs(addrs);
+    }
+
+    let mut network_interfaces = Vec::new();
+
+    // Assume all link_addresses have unique names for now
+    for (n, m) in link_addresses {
+        if let Some(n_addr) = network_addresses.get(&n) {
+            let network_interface = NetworkInterface::create(
+                n,
+                n_addr.source_ip_hint,
+                n_addr.broadcast,
+                m.mac,
+            );
+            network_interfaces.push(network_interface);
+        };
+    }
+
+    Ok(network_interfaces)
+}
+
 #[repr(C)]
 struct IfAddrs {
     ifa_next: *mut IfAddrs,
@@ -51,8 +236,7 @@ unsafe extern "C" {
 }
 
 struct NetworkAddress {
-    ip: Ipv4Addr,
-    netmask: Ipv4Addr,
+    source_ip_hint: Ipv4Addr,
     broadcast: Ipv4Addr,
 }
 
@@ -63,119 +247,26 @@ struct LinkAddress {
 struct NetworkInterface {
     name: String,
     ip: Ipv4Addr,
-    _netmask: Ipv4Addr,
     broadcast: Ipv4Addr,
     _mac: [u8; 6],
 }
 
 impl NetworkInterface {
-    fn create(name: String, ip: Ipv4Addr, netmask: Ipv4Addr, broadcast: Ipv4Addr, mac: [u8; 6]) -> Self {
+    fn create(
+        name: String,
+        ip: Ipv4Addr,
+        broadcast: Ipv4Addr,
+        mac: [u8; 6],
+    ) -> Self {
         Self {
             name,
             ip,
-            _netmask: netmask,
             broadcast,
             _mac: mac,
         }
     }
 }
 
-pub struct LocalNetwork {
-    pub source_ip_hint: Ipv4Addr,
-    pub subnet_broadcast: Ipv4Addr,
-}
-
-pub fn get_local_networks() -> WResult<Vec<LocalNetwork>> {
-    let mut networks = Vec::new();
-    let interfaces = get_network_interfaces()?;
-    let mut unique_broadcast_addresses = Vec::new();
-    for i in &interfaces {
-        if unique_broadcast_addresses.contains(&i.broadcast) {
-            continue;
-        }
-
-        // man systemd.net-naming-scheme
-        // Only broadcast to local network
-        let iname = &i.name;
-        if iname.starts_with("en") || iname.starts_with("wl") || iname.starts_with("eth") {
-            unique_broadcast_addresses.push(i.broadcast);
-            let local_network = LocalNetwork {
-                source_ip_hint: i.ip,
-                subnet_broadcast: i.broadcast,
-            };
-            networks.push(local_network);
-        }
-    }
-
-    Ok(networks)
-}
-
-pub(crate) fn find_local_networks_with_mac(mac: Mac) -> WResult<Vec<LocalNetwork>> {
-    todo!()
-}
-
-fn get_network_interfaces() -> WResult<Vec<NetworkInterface>> {
-    let mut network_addresses = HashMap::new();
-    let mut link_addresses = HashMap::new();
-    let mut addrs: *mut IfAddrs = std::ptr::null_mut();
-
-    unsafe {
-        let stat = getifaddrs(&mut addrs);
-        if stat != 0 {
-            return Err(WError::FfiFailed(format!(
-                "Failed to call libc:getifaddrs, returned {}",
-                stat
-            )));
-        }
-
-        let mut cur = addrs;
-        while !cur.is_null() {
-            let ifa = &*cur;
-            let name = CStr::from_ptr(ifa.ifa_name).to_string_lossy().to_string();
-            if ifa.ifa_addr.is_null() {
-                cur = ifa.ifa_next;
-                continue;
-            }
-
-            let family = (*ifa.ifa_addr).sa_family;
-            if family == AF_INET {
-                let sa_ip = ifa.ifa_addr as *const SockAddrIn;
-                let sa_netmask = ifa.ifa_netmask as *const SockAddrIn;
-                let ip = read_sa_ip(sa_ip);
-                let netmask = read_sa_ip(sa_netmask);
-                let broadcast = calculate_broadcast_address(ip, netmask);
-
-                let network_address = NetworkAddress { ip, netmask, broadcast };
-
-                network_addresses.insert(name, network_address);
-            } else if family == AF_PACKET {
-                let sock_addr_ll = ifa.ifa_addr as *const SockAddrLl;
-                let mac = read_sa_ll(sock_addr_ll);
-
-                let link_address = LinkAddress { mac };
-
-                link_addresses.insert(name, link_address);
-            }
-
-            cur = ifa.ifa_next;
-        }
-
-        freeifaddrs(addrs);
-    }
-
-    let mut network_interfaces = Vec::new();
-
-    // Assume all link_addresses have unique names for now
-    for (n, m) in link_addresses {
-        if let Some(n_addr) = network_addresses.get(&n) {
-            let network_interface = NetworkInterface::create(n, n_addr.ip, n_addr.netmask, n_addr.broadcast, m.mac);
-            network_interfaces.push(network_interface);
-        };
-    }
-
-    Ok(network_interfaces)
-}
-
 fn calculate_broadcast_address(ip: Ipv4Addr, netmask: Ipv4Addr) -> Ipv4Addr {
     let ip_octets = ip.octets();
     let netmask_octets = netmask.octets();
@@ -202,3 +293,59 @@ fn read_sa_ll(ifa_addr: *const SockAddrLl) -> [u8; 6] {
         [mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]]
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::{net::Ipv4Addr, str::FromStr};
+
+    use super::find_ip_from_arp;
+    use crate::mac::Mac;
+
+    #[test]
+    fn arp_file_parse() {
+        validate_mapping("ae:a7:f1:0a:f2:ed", "192.168.0.193");
+        validate_mapping("04:7c:16:6e:c0:8c", "192.168.0.8");
+        validate_mapping("58:04:4f:67:b3:7c", "192.168.0.1");
+    }
+
+    #[test]
+    fn arp_file_parse_not_found() {
+        let mac = Mac::create("ae:a7:f1:0a:f2:ee").unwrap();
+        let ip = find_ip_from_mac_against_test_data(&mac);
+        assert!(ip.is_none());
+    }
+
+    #[test]
+    fn get_local_networks_should_work() {
+        assert!(super::get_local_networks().is_ok(), "Check the FFI bindings code")
+    }
+
+    #[test]
+    fn calculate_broadcast_address_correctly() {
+        validate_broadcast_address_calculation("192.168.0.8", "255.255.255.0", "192.168.0.255");
+        validate_broadcast_address_calculation("192.168.0.8", "255.255.0.0", "192.168.255.255");
+        validate_broadcast_address_calculation("192.168.1.8", "255.255.0.0", "192.168.255.255");
+        validate_broadcast_address_calculation("192.168.1.8", "255.255.240.0", "192.168.15.255");
+    }
+
+    fn validate_mapping(mac: &str, expected_ip: &str) {
+        let mac = Mac::create(mac).unwrap();
+        let ip = find_ip_from_mac_against_test_data(&mac)
+            .expect(&format!("IP mapping for {} is available in test data", &mac));
+
+        assert_eq!(expected_ip, ip.to_string());
+    }
+
+    fn find_ip_from_mac_against_test_data(mac: &Mac) -> Option<Ipv4Addr> {
+        let path = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("src/test_data/arp_file");
+        find_ip_from_arp(mac, &path.to_string_lossy().to_string())
+    }
+
+    fn validate_broadcast_address_calculation(ip: &str, netmask: &str, expected_broadcast: &str) {
+        let ip = Ipv4Addr::from_str(ip).unwrap();
+        let netmask = Ipv4Addr::from_str(netmask).unwrap();
+        let expected_broadcast = Ipv4Addr::from_str(expected_broadcast).unwrap();
+        let actual_broadcast = super::calculate_broadcast_address(ip, netmask);
+        assert_eq!(expected_broadcast, actual_broadcast);
+    }
+}

src/test_data/arp_file

@@ -0,0 +1,4 @@
+IP address       HW type     Flags       HW address            Mask     Device
+192.168.0.8      0x1         0x2         04:7c:16:6e:c0:8c     *        wlan0
+192.168.0.1      0x1         0x2         58:04:4f:67:b3:7c     *        wlan0
+192.168.0.193    0x1         0x2         ae:a7:f1:0a:f2:ed     *        wlan0

src/wolz.rs

@@ -1,7 +1,9 @@
-use std::net::UdpSocket;
+use std::{
+    io::Write,
+    net::{TcpStream, UdpSocket},
+};
 
 use crate::{
-    arp,
     config::Config,
     error::{WError, WResult},
     mac::Mac,
@@ -55,10 +57,18 @@ impl Wolz {
         Ok(())
     }
 
-    pub fn shut_down(&self, mac_or_nick: &str) -> WResult<()> {
+    // TODO: Fallback to full network scan if /proc/net/arp file lookup fails
+    fn shut_down(&self, mac_or_nick: &str) -> WResult<()> {
         let mac = self.config.get_mac(mac_or_nick)?;
-        let ip_from_arp = netif::find_local_networks_with_mac(mac)?;
-        todo!()
+        let ip = netif::find_ip_with_mac(mac)?;
+
+        println!("Sending shutdown signal to {}:21367", ip);
+        let mut stream = TcpStream::connect(format!("{}:21367", ip)).map_err(WError::TcpSocketBindError)?;
+        stream
+            .write("shutdown".as_bytes())
+            .map_err(WError::TcpSocketWriteError)?;
+
+        Ok(())
     }
 }
 
@@ -67,10 +77,13 @@ fn try_send_magic_bytes(magic_bytes: &[u8; 102], mac: &Mac, local_network: &Loca
     let broadcast_addr = format!("{}:9", local_network.subnet_broadcast);
     match send_magic_bytes(&magic_bytes, &send_addr, &broadcast_addr) {
         Ok(()) => {
-            println!("Sent magic pkt {} -> {} for Mac {}", send_addr, broadcast_addr, mac);
+            println!(
+                "Sent WoL magic packet {} -> {} for mac {}",
+                send_addr, broadcast_addr, mac
+            );
         }
         Err(e) => println!(
-            "Unable to send magic pkt {} -> {} for Mac {}, because {}",
+            "Unable to send WoL magic packet {} -> {} for mac {}, because {}",
             send_addr, broadcast_addr, mac, e
         ),
     }