Nameserver information to network block (#2058)

* doc: added documentation of nameserver

cspell.yaml

@@ -1,4 +1,4 @@
-version: '0.2'
+version: "0.2"
 language: en-US, en-GB
 allowCompoundWords: true
 ignorePaths:
@@ -124,6 +124,7 @@ words:
   - recip
   - repr
   - reqwest
+  - resolv
   - retval
   - rofi
   - rofication

src/blocks/net.rs

@@ -31,6 +31,7 @@
 //! `bitrate`         | WiFi connection bitrate     | Number | Bits per second
 //! `ip`              | IPv4 address of the iface   | Text   | -
 //! `ipv6`            | IPv6 address of the iface   | Text   | -
+//! `nameserver`      | Nameserver                  | Text   | -
 //!
 //! # Example
 //!
@@ -61,6 +62,7 @@
 use super::prelude::*;
 use crate::netlink::NetDevice;
 use crate::util;
+use itertools::Itertools;
 use regex::Regex;
 use std::time::Instant;
 
@@ -159,6 +161,13 @@ pub async fn run(config: &Config, api: &CommonApi) -> Result<()> {
                     [if let Some(v) = device.frequency()] "frequency" => Value::hertz(v),
                     [if let Some(v) = device.bitrate()] "bitrate" => Value::bits(v),
                     [if let Some(v) = device.signal()] "signal_strength" => Value::percents(v),
+                    [if !device.nameservers.is_empty()] "nameserver" => Value::text(
+                                                                            device
+                                                                                .nameservers
+                                                                                .into_iter()
+                                                                                .map(|s| s.to_string())
+                                                                                .join(" "),
+                                                                        ),
                     "device" => Value::text(device.iface.name),
                 });
 

src/netlink.rs

@@ -9,7 +9,7 @@ use regex::Regex;
 
 use libc::c_uchar;
 
-use std::net::{Ipv4Addr, Ipv6Addr};
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
 use std::ops;
 use std::path::Path;
 
@@ -27,6 +27,7 @@ pub struct NetDevice {
     pub ipv6: Option<Ipv6Addr>,
     pub icon: &'static str,
     pub tun_wg_ppp: bool,
+    pub nameservers: Vec<IpAddr>,
 }
 
 #[derive(Debug, Default)]
@@ -67,6 +68,9 @@ impl NetDevice {
         let wifi_info = WifiInfo::new(iface.index).await?;
         let ip = ipv4(&mut sock, iface.index).await?;
         let ipv6 = ipv6(&mut sock, iface.index).await?;
+        let nameservers = read_nameservers()
+            .await
+            .error("Failed to read nameservers")?;
 
         // TODO: use netlink for the these too
         // I don't believe that this should ever change, so set it now:
@@ -97,6 +101,7 @@ impl NetDevice {
             ipv6,
             icon,
             tun_wg_ppp: tun | wg | ppp,
+            nameservers,
         }))
     }
 
@@ -428,6 +433,24 @@ async fn ipv6(sock: &mut NlSocket, ifa_index: i32) -> Result<Option<Ipv6Addr>> {
         .map(Ipv6Addr::from))
 }
 
+async fn read_nameservers() -> Result<Vec<IpAddr>> {
+    let file = util::read_file("/etc/resolv.conf")
+        .await
+        .error("Failed to read /etc/resolv.conf")?;
+    let mut nameservers = Vec::new();
+
+    for line in file.lines() {
+        let mut line_parts = line.split_whitespace();
+        if line_parts.next() == Some("nameserver") {
+            if let Some(ip) = line_parts.next() {
+                nameservers.push(ip.parse().error("Unable to parse ip")?);
+            }
+        }
+    }
+
+    Ok(nameservers)
+}
+
 // Source: https://www.kernel.org/doc/Documentation/networking/operstates.txt
 #[derive(Debug, PartialEq, Eq)]
 pub enum Operstate {