Addressed cargo clippy comments.

Refactored network code to improve readability.

src/fortivpn.rs

@@ -53,19 +53,15 @@ pub async fn get_oauth_cookie(config: &Config) -> Result<String, FortiError> {
     };
     let mut socket = BufStream::new(socket);
     let headers = http::read_headers(&mut socket).await?;
-    let token_id = headers
-        .lines()
-        .next()
-        .map(|line| {
-            if !line.starts_with("GET /?id=") {
-                return None;
-            }
-            let start_index = line.find("=")?;
-            let line = &line[start_index + 1..];
-            let end_index = line.find(" ")?;
-            Some((&line[..end_index]).to_string())
-        })
-        .flatten();
+    let token_id = headers.lines().next().and_then(|line| {
+        if !line.starts_with("GET /?id=") {
+            return None;
+        }
+        let start_index = line.find("=")?;
+        let line = &line[start_index + 1..];
+        let end_index = line.find(" ")?;
+        Some(line[..end_index].to_string())
+    });
 
     let token_id = if let Some(token_id) = token_id {
         token_id
@@ -108,7 +104,7 @@ pub async fn get_oauth_cookie(config: &Config) -> Result<String, FortiError> {
                 if let Some(start_index) = line.find(":") {
                     let line = &line[start_index + 2..];
                     if let Some(end_index) = line.find("; ") {
-                        cookie = Some((&line[..end_index]).to_string());
+                        cookie = Some(line[..end_index].to_string());
                     }
                 }
             }
@@ -168,7 +164,7 @@ impl FortiVPNTunnel {
     }
 
     pub fn mtu(&self) -> usize {
-        self.mtu as usize
+        self.mtu
     }
 
     async fn connect(hostport: &str, domain: &str) -> Result<BufTlsStream, FortiError> {
@@ -283,7 +279,7 @@ impl FortiVPNTunnel {
                         .iter_options()
                         .collect::<Result<Vec<_>, ppp::FormatError>>();
                     let options_match = match received_opts {
-                        Ok(received_opts) => &opts == received_opts.as_slice(),
+                        Ok(received_opts) => opts == received_opts.as_slice(),
                         Err(err) => {
                             debug!("Failed to decode LCP Ack options: {}", err);
                             return Err("Failed to decode LCP Ack options".into());
@@ -504,7 +500,7 @@ impl FortiVPNTunnel {
         packet_header[6..].copy_from_slice(&protocol.value().to_be_bytes());
 
         socket.write_all(&packet_header).await?;
-        Ok(socket.write_all(&ppp_data).await?)
+        Ok(socket.write_all(ppp_data).await?)
     }
 
     async fn read_ppp_packet(
@@ -781,9 +777,7 @@ impl PPPState {
                 }
             }
         }
-        if let Err(err) = self.validate_link(socket).await {
-            return Err(err);
-        }
+        self.validate_link(socket).await?;
 
         let mut ppp_size = [0u8; 2];
         ppp_size.copy_from_slice(&self.ppp_header[..2]);
@@ -799,7 +793,7 @@ impl PPPState {
             );
             return Err("Header has conflicting length data".into());
         }
-        if magic != &[0x50, 0x50] {
+        if magic != [0x50, 0x50] {
             debug!(
                 "Found {:x}{:x} instead of magic",
                 self.ppp_header[2], self.ppp_header[3]

src/http.rs

@@ -37,7 +37,7 @@ pub async fn read_content<S>(socket: &mut S, headers: &str) -> Result<String, Ht
 where
     S: AsyncRead + AsyncBufRead + AsyncWrite + Unpin,
 {
-    if headers.find("Transfer-Encoding: chunked").is_some() {
+    if headers.contains("Transfer-Encoding: chunked") {
         // This is super janky, but should work if chunks are small enough.
         // openfortivpn works the same way.
         return read_until(socket, CHUNKS_END_MARKER).await;
@@ -60,9 +60,9 @@ where
 pub fn read_content_length(headers: &str) -> Option<usize> {
     const CONTENT_LENGTH_HEADER: &str = "Content-Length: ";
     for line in headers.lines() {
-        if line.starts_with(CONTENT_LENGTH_HEADER) {
-            match &line[CONTENT_LENGTH_HEADER.len()..].parse::<usize>() {
-                Ok(content_length) => return Some(*content_length),
+        if let Some(content_length) = line.strip_prefix(CONTENT_LENGTH_HEADER) {
+            match content_length.parse::<usize>() {
+                Ok(content_length) => return Some(content_length),
                 Err(err) => {
                     warn!("Failed to parse content-length: {}", err);
                     continue;
@@ -76,8 +76,8 @@ pub fn read_content_length(headers: &str) -> Option<usize> {
 pub fn read_host(headers: &str) -> Option<&str> {
     const HOST_HEADER: &str = "Host: ";
     for line in headers.lines() {
-        if line.starts_with(HOST_HEADER) {
-            return Some(&line[HOST_HEADER.len()..]);
+        if let Some(host) = line.strip_prefix(HOST_HEADER) {
+            return Some(host);
         }
     }
     None