api2/node/dns.rs: implement resolv.conf parser

src/api2/node/dns.rs

@@ -1,27 +1,75 @@
 use failure::*;
 
+
 use crate::tools;
+use crate::tools::common_regex;
+
 use crate::api::schema::*;
 use crate::api::router::*;
+
+use lazy_static::lazy_static;
+
+use std::io::{BufRead, BufReader};
+
 use serde_json::{json, Value};
 
+static RESOLV_CONF_FN: &str = "/etc/resolv.conf";
+
+fn read_etc_resolv_conf() -> Result<Value, Error> {
+
+    let mut result = json!({});
+
+    let mut nscount = 0;
+
+    let file = std::fs::File::open(RESOLV_CONF_FN)?;
+    let mut reader = BufReader::new(file);
+
+    let test = IPRE!();
+
+    lazy_static! {
+        static ref DOMAIN_REGEX: regex::Regex = regex::Regex::new(r"^\s*(?:search|domain)\s+(\S+)\s*").unwrap();
+        static ref SERVER_REGEX: regex::Regex = regex::Regex::new(
+            concat!(r"^\s*nameserver\s+(", IPRE!(),  r")\s*")).unwrap();
+    }
+
+    for line in reader.lines() {
+        let line = line?;
+
+        if let Some(m) = DOMAIN_REGEX.find(&line) {
+            let domain = m.as_str();
+            result["search"] = Value::from(domain);
+        } else if let Some(m) = SERVER_REGEX.find(&line) {
+            nscount += 1;
+            if nscount > 3 { continue };
+            let nameserver = m.as_str();
+            let id = format!("dns{}", nscount);
+            result[id] = Value::from(m.as_str());
+        }
+    }
+
+    Ok(result)
+}
 
 fn get_dns(_param: Value, _info: &ApiMethod) -> Result<Value, Error> {
 
-    Ok(json!({
-        "search": "test.com",
-        "dns1": "1.2.3.4",
-        "dns2": "1.2.3.4",
-        "dns3": "1.2.3.4",
-    }))
+    read_etc_resolv_conf()
 }
 
 pub fn router() -> Router {
 
     let route = Router::new()
-        .get(ApiMethod::new(
-            get_dns,
-            ObjectSchema::new("Read DNS settings.")));
+        .get(
+            ApiMethod::new(
+                get_dns,
+                ObjectSchema::new("Read DNS settings.")
+            ).returns(
+                ObjectSchema::new("Returns DNS server IPs and sreach domain.")
+                    .optional("search", StringSchema::new("Search domain for host-name lookup."))
+                    .optional("dns1", StringSchema::new("First name server IP address."))
+                    .optional("dns2", StringSchema::new("Second name server IP address."))
+                    .optional("dns3", StringSchema::new("Third name server IP address."))
+            )
+        );
 
     route
 }

src/lib.rs

@@ -1,3 +1,4 @@
+#[macro_use]
 pub mod tools;
 
 /// API definition helper

src/tools.rs

@@ -1,7 +1,6 @@
 //! Tools and utilities
 //!
 //! This is a collection of small and useful tools.
-
 use failure::*;
 use nix::unistd;
 use nix::sys::stat;
@@ -22,6 +21,8 @@ use serde_json::Value;
 
 pub mod timer;
 pub mod wrapped_reader_stream;
+#[macro_use]
+pub mod common_regex;
 
 /// The `BufferedReader` trait provides a single function
 /// `buffered_read`. It returns a reference to an internal buffer. The

src/tools/common_regex.rs

@@ -0,0 +1,32 @@
+//! Predefined Regular Expressions
+//!
+//! This is a collection of useful regular expressions
+
+use lazy_static::lazy_static;
+
+#[macro_export]
+macro_rules! IPV4OCTET { () => (r"(?:25[0-5]|(?:2[0-4]|1[0-9]|[1-9])?[0-9])") }
+#[macro_export]
+macro_rules! IPV6H16 { () => (r"(?:[0-9a-fA-F]{1,4})") }
+#[macro_export]
+macro_rules! IPV6LS32 { () => (concat!(r"(?:(?:", IPV4RE!(), "|", IPV6H16!(), ":", IPV6H16!(), "))" )) }
+
+
+#[macro_export]
+macro_rules! IPV4RE { () => (concat!(r"(?:(?:", IPV4OCTET!(), r"\.){3}", IPV4OCTET!(), ")")) }
+
+#[macro_export]
+macro_rules! IPV6RE { () => (concat!(r"(?:",
+    r"(?:(?:",                                               r"(?:", IPV6H16!(), r":){6})", IPV6LS32!(), r")|",
+    r"(?:(?:",                                             r"::(?:", IPV6H16!(), r":){5})", IPV6LS32!(), r")|",
+    r"(?:(?:(?:",                            IPV6H16!(), r")?::(?:", IPV6H16!(), r":){4})", IPV6LS32!(), r")|",
+    r"(?:(?:(?:(?:", IPV6H16!(), r":){0,1}", IPV6H16!(), r")?::(?:", IPV6H16!(), r":){3})", IPV6LS32!(), r")|",
+    r"(?:(?:(?:(?:", IPV6H16!(), r":){0,2}", IPV6H16!(), r")?::(?:", IPV6H16!(), r":){2})", IPV6LS32!(), r")|",
+    r"(?:(?:(?:(?:", IPV6H16!(), r":){0,3}", IPV6H16!(), r")?::(?:", IPV6H16!(), r":){1})", IPV6LS32!(), r")|",
+    r"(?:(?:(?:(?:", IPV6H16!(), r":){0,4}", IPV6H16!(), r")?::",                      ")", IPV6LS32!(), r")|",
+    r"(?:(?:(?:(?:", IPV6H16!(), r":){0,5}", IPV6H16!(), r")?::",                      ")", IPV6H16!(),  r")|",
+    r"(?:(?:(?:(?:", IPV6H16!(), r":){0,6}", IPV6H16!(), r")?::",                                        ")))"))
+}
+
+#[macro_export]
+macro_rules! IPRE { () => (concat!(r"(?:", IPV4RE!(), "|", IPV6RE!(), ")")) }