protocol: support old servers (protocol 48)

master/src/master_server.rs

@@ -252,10 +252,10 @@ impl MasterServer {
                     let p = server::GetServerInfoResponse {
                         map: self.update_map.as_ref(),
                         host: self.update_title.as_ref(),
-                        protocol: 49,
+                        protocol: 48, // XXX: how to detect what version client will accept?
                         dm: true,
                         maxcl: 32,
-                        gamedir: "valve",
+                        gamedir: "valve", // XXX: probably must be specific for client...
                         ..Default::default()
                     };
                     trace!("{}: send {:?}", from, p);
@@ -334,7 +334,7 @@ impl MasterServer {
                 }
             }
         } else {
-            debug!("invalid packet: \"{}\"", Str(src));
+            debug!("{}: invalid packet: \"{}\"", from, Str(src));
         }
 
         Ok(())

protocol/src/filter.rs

@@ -87,23 +87,36 @@ impl<T> From<&ServerAdd<T>> for FilterFlags {
 pub struct Version {
     pub major: u8,
     pub minor: u8,
+    pub patch: u8,
 }
 
 impl Version {
     pub const fn new(major: u8, minor: u8) -> Self {
-        Self { major, minor }
+        Self::with_patch(major, minor, 0)
+    }
+
+    pub const fn with_patch(major: u8, minor: u8, patch: u8) -> Self {
+        Self {
+            major,
+            minor,
+            patch,
+        }
     }
 }
 
 impl fmt::Debug for Version {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "{}.{}", self.major, self.minor)
+        write!(fmt, "{}.{}", self.major, self.minor)?;
+        if self.patch != 0 {
+            write!(fmt, ".{}", self.patch)?;
+        }
+        Ok(())
     }
 }
 
 impl fmt::Display for Version {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "{}.{}", self.major, self.minor)
+        <Self as fmt::Debug>::fmt(self, fmt)
     }
 }
 
@@ -111,8 +124,12 @@ impl FromStr for Version {
     type Err = ParseIntError;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let (major, minor) = s.split_once('.').unwrap_or((s, "0"));
+        let (major, tail) = s.split_once('.').unwrap_or((s, "0"));
-        Ok(Self::new(major.parse()?, minor.parse()?))
+        let (minor, patch) = tail.split_once('.').unwrap_or((tail, "0"));
+        let major = major.parse()?;
+        let minor = minor.parse()?;
+        let patch = patch.parse()?;
+        Ok(Self::with_patch(major, minor, patch))
     }
 }
 

protocol/src/master.rs

@@ -9,13 +9,13 @@ use super::Error;
 #[derive(Clone, Debug, PartialEq)]
 pub struct ChallengeResponse {
     pub master_challenge: u32,
-    pub server_challenge: u32,
+    pub server_challenge: Option<u32>,
 }
 
 impl ChallengeResponse {
     pub const HEADER: &'static [u8] = b"\xff\xff\xff\xffs\n";
 
-    pub fn new(master_challenge: u32, server_challenge: u32) -> Self {
+    pub fn new(master_challenge: u32, server_challenge: Option<u32>) -> Self {
         Self {
             master_challenge,
             server_challenge,
@@ -26,7 +26,11 @@ impl ChallengeResponse {
         let mut cur = Cursor::new(src);
         cur.expect(Self::HEADER)?;
         let master_challenge = cur.get_u32_le()?;
-        let server_challenge = cur.get_u32_le()?;
+        let server_challenge = if cur.remaining() == 4 {
+            Some(cur.get_u32_le()?)
+        } else {
+            None
+        };
         cur.expect_empty()?;
         Ok(Self {
             master_challenge,
@@ -35,11 +39,13 @@ impl ChallengeResponse {
     }
 
     pub fn encode<const N: usize>(&self, buf: &mut [u8; N]) -> Result<usize, Error> {
-        Ok(CursorMut::new(buf)
+        let mut cur = CursorMut::new(buf);
-            .put_bytes(Self::HEADER)?
+        cur.put_bytes(Self::HEADER)?;
-            .put_u32_le(self.master_challenge)?
+        cur.put_u32_le(self.master_challenge)?;
-            .put_u32_le(self.server_challenge)?
+        if let Some(server_challenge) = self.server_challenge {
-            .pos())
+            cur.put_u32_le(server_challenge)?;
+        }
+        Ok(cur.pos())
     }
 }
 
@@ -222,7 +228,21 @@ mod tests {
 
     #[test]
     fn challenge_response() {
-        let p = ChallengeResponse::new(0x12345678, 0x87654321);
+        let p = ChallengeResponse::new(0x12345678, Some(0x87654321));
+        let mut buf = [0; 512];
+        let n = p.encode(&mut buf).unwrap();
+        assert_eq!(ChallengeResponse::decode(&buf[..n]), Ok(p));
+    }
+
+    #[test]
+    fn challenge_response_old() {
+        let s = b"\xff\xff\xff\xffs\n\x78\x56\x34\x12";
+        assert_eq!(
+            ChallengeResponse::decode(s),
+            Ok(ChallengeResponse::new(0x12345678, None))
+        );
+
+        let p = ChallengeResponse::new(0x12345678, None);
         let mut buf = [0; 512];
         let n = p.encode(&mut buf).unwrap();
         assert_eq!(ChallengeResponse::decode(&buf[..n]), Ok(p));

protocol/src/server.rs

@@ -13,29 +13,35 @@ use super::Error;
 
 #[derive(Clone, Debug, PartialEq)]
 pub struct Challenge {
-    pub server_challenge: u32,
+    pub server_challenge: Option<u32>,
 }
 
 impl Challenge {
     pub const HEADER: &'static [u8] = b"q\xff";
 
-    pub fn new(server_challenge: u32) -> Self {
+    pub fn new(server_challenge: Option<u32>) -> Self {
         Self { server_challenge }
     }
 
     pub fn decode(src: &[u8]) -> Result<Self, Error> {
         let mut cur = Cursor::new(src);
         cur.expect(Self::HEADER)?;
-        let server_challenge = cur.get_u32_le()?;
+        let server_challenge = if cur.remaining() == 4 {
+            Some(cur.get_u32_le()?)
+        } else {
+            None
+        };
         cur.expect_empty()?;
         Ok(Self { server_challenge })
     }
 
     pub fn encode<const N: usize>(&self, buf: &mut [u8; N]) -> Result<usize, Error> {
-        Ok(CursorMut::new(buf)
+        let mut cur = CursorMut::new(buf);
-            .put_bytes(Self::HEADER)?
+        cur.put_bytes(Self::HEADER)?;
-            .put_u32_le(self.server_challenge)?
+        if let Some(server_challenge) = self.server_challenge {
-            .pos())
+            cur.put_u32_le(server_challenge)?;
+        }
+        Ok(cur.pos())
     }
 }
 
@@ -264,7 +270,15 @@ where
                 b"map" => ret.map = cur.get_key_value()?,
                 b"type" => ret.server_type = cur.get_key_value()?,
                 b"os" => ret.os = cur.get_key_value()?,
-                b"version" => ret.version = cur.get_key_value()?,
+                b"version" => {
+                    ret.version = cur
+                        .get_key_value()
+                        .map_err(|e| {
+                            debug!("invalid server version");
+                            e
+                        })
+                        .unwrap_or_default()
+                }
                 b"region" => ret.region = cur.get_key_value()?,
                 b"product" => ret.product = cur.get_key_value()?,
                 b"bots" => ret.flags.set(ServerFlags::BOTS, cur.get_key_value()?),
@@ -460,12 +474,23 @@ mod tests {
 
     #[test]
     fn challenge() {
-        let p = Challenge::new(0x12345678);
+        let p = Challenge::new(Some(0x12345678));
         let mut buf = [0; 128];
         let n = p.encode(&mut buf).unwrap();
         assert_eq!(Challenge::decode(&buf[..n]), Ok(p));
     }
 
+    #[test]
+    fn challenge_old() {
+        let s = b"q\xff";
+        assert_eq!(Challenge::decode(s), Ok(Challenge::new(None)));
+
+        let p = Challenge::new(None);
+        let mut buf = [0; 128];
+        let n = p.encode(&mut buf).unwrap();
+        assert_eq!(&buf[..n], b"q\xff");
+    }
+
     #[test]
     fn server_add() {
         let p = ServerAdd {