[FIX] Rust: fix unsetting source udp address when not specified by the user

src/rust/src/args.rs

@@ -174,10 +174,9 @@ pub struct Args {
     pub segmentonkeyonly: bool,
     /// Read the input via UDP (listening in the specified port)
     /// instead of reading a file.
-    /// Host can be a
-    /// hostname or IPv4 address. If host is not specified
-    /// then listens on the local host.
-    #[arg(long, value_name="[host:]port", verbatim_doc_comment, help_heading=NETWORK_SUPPORT)]
+    /// Host and src can be a hostname or IPv4 address.
+    /// If host is not specified then listens on the local host.
+    #[arg(long, value_name="[[src@]host:]port", verbatim_doc_comment, help_heading=NETWORK_SUPPORT)]
     pub udp: Option<String>,
     /// Can be a hostname or IPv4 address.
     #[arg(long, value_name="port", verbatim_doc_comment, help_heading=NETWORK_SUPPORT)]

src/rust/src/parser.rs

@@ -1321,23 +1321,33 @@ impl OptionsExt for Options {
 
         // Network stuff
         if let Some(ref udp) = args.udp {
-            if let Some(at) = udp.find('@') {
-                let addr = &udp[0..at];
-                let port = &udp[at + 1..];
+            let mut remaining_udp = udp.as_str();
 
-                self.udpsrc = Some(udp.clone());
-                self.udpaddr = Some(addr.to_owned());
-                self.udpport = port.parse().unwrap();
-            } else if let Some(colon) = udp.find(':') {
-                let addr = &udp[0..colon];
-                let port = get_atoi_hex(&udp[colon + 1..]);
+            if let Some(at) = remaining_udp.find('@') {
+                let src = &remaining_udp[0..at];
+                self.udpsrc = Some(src.to_owned());
+
+                remaining_udp = &remaining_udp[at + 1..];
+            }
+
+            if let Some(colon) = remaining_udp.find(':') {
+                let addr = &remaining_udp[0..colon];
+                let port = get_atoi_hex(&remaining_udp[colon + 1..]);
 
-                self.udpsrc = Some(udp.clone());
                 self.udpaddr = Some(addr.to_owned());
                 self.udpport = port;
             } else {
-                self.udpaddr = None;
-                self.udpport = udp.parse().unwrap();
+                match remaining_udp.parse() {
+                    Ok(port) => {
+                        self.udpport = port;
+                    }
+                    Err(_) => {
+                        fatal!(
+                            cause = ExitCause::MalformedParameter;
+                           "Invalid UDP parameter\n"
+                        );
+                    }
+                }
             }
 
             self.input_source = DataSource::Network;