feat: Add SrvRdata struct for SRV resource record type

src/message/rdata/srv_rdata.rs

@@ -0,0 +1,48 @@
+use crate::domain_name::DomainName;
+
+
+/// RFC 2782: https://datatracker.ietf.org/doc/html/rfc2782
+/// An struct that represents the `Rdata` for srv type.
+
+pub struct SrvRdata {
+    /// The priority of this target host. A client MUST attempt to contact the target host with the lowest-numbered priority it can reach; target hosts with the same priority SHOULD be tried in an order defined by the weight field.
+    priority: u16,
+    /// A server selection mechanism. The weight field specifies a relative weight for entries with the same priority. Larger weights SHOULD be given a proportionately higher probability of being selected.
+    weight: u16,
+    /// The port on this target host of this service.
+    port: u16,
+    /// The domain name of the target host.
+    target: DomainName,
+}
+
+impl SrvRdata {
+
+    /// Creates a new `SrvRdata` with default values.
+    /// 
+    /// # Example
+    /// ```
+    /// let srv_rdata = SrvRdata::new();
+    /// ```
+    pub fn new() -> SrvRdata {
+        SrvRdata {
+            priority: 0,
+            weight: 0,
+            port: 0,
+            target: DomainName::new(),
+        }
+    }
+
+    /// Creates a new `SrvRdata` with the specified values.
+    /// # Example
+    /// ```
+    /// let srv_rdata = SrvRdata::new_with_values(1, 2, 3, DomainName::new_from_str("www.example.com"));
+    /// ```
+    pub fn new_with_values(priority: u16, weight: u16, port: u16, target: DomainName) -> SrvRdata {
+        SrvRdata {
+            priority,
+            weight,
+            port,
+            target,
+        }
+    }
+}