[feature] Support PPP Decode

2 files changed, 117 insertions, 1 deletions

diff --git a/src/protocol/mod.rs b/src/protocol/mod.rs
index 1f02684..16b9963 100644
--- a/src/protocol/mod.rs
+++ b/src/protocol/mod.rs
@@ -15,4 +15,5 @@ pub mod gtpv1;
 pub mod l2tp;
 pub mod grev0;
 pub mod grev1;
-pub mod pptp;
\ No newline at end of file
+pub mod pptp;
+pub mod ppp;
\ No newline at end of file
diff --git a/src/protocol/ppp.rs b/src/protocol/ppp.rs
new file mode 100644
index 0000000..e625cb6
--- /dev/null
+++ b/src/protocol/ppp.rs
@@ -0,0 +1,115 @@
+use crate::protocol::codec::Decode;
+use nom::number;
+use nom::IResult;
+
+/******************************************************************************
+ * Struct
+ ******************************************************************************/
+
+// https://www.iana.org/assignments/ppp-numbers/ppp-numbers.xhtml
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum PppProtocol {
+    PAD,  // Padding Protocol
+    IPv4, // Internet Protocol version 4 (IPv4)
+    IPv6, // Internet Protocol version 6 (IPv6)
+    IPCP, // Internet Protocol Control Protocol (IPCP)
+    CCP,  // Compression Control Protocol (CCP)
+    LCP,  // Link Control Protocol (LCP)
+    PAP,  // Password Authentication Protocol (PAP)
+    CHAP, // Challenge Handshake Authentication Protocol (CHAP)
+    Other(u16),
+}
+
+// https://www.rfc-editor.org/rfc/rfc1661.html
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct PppHeader {
+    pub address: u8,
+    pub control: u8,
+    pub protocol: PppProtocol,
+}
+
+/******************************************************************************
+ * API
+ ******************************************************************************/
+
+impl From<u16> for PppProtocol {
+    fn from(raw: u16) -> Self {
+        match raw {
+            0x0001 => PppProtocol::PAD,
+            0x0021 => PppProtocol::IPv4,
+            0x0057 => PppProtocol::IPv6,
+            0x8021 => PppProtocol::IPCP,
+            0x80FD => PppProtocol::CCP,
+            0xC021 => PppProtocol::LCP,
+            0xC023 => PppProtocol::PAP,
+            0xC223 => PppProtocol::CHAP,
+            other => PppProtocol::Other(other),
+        }
+    }
+}
+
+impl Decode for PppProtocol {
+    type Iterm = PppProtocol;
+    fn decode(input: &[u8]) -> IResult<&[u8], PppProtocol> {
+        let (input, protocol) = number::streaming::be_u16(input)?;
+
+        Ok((input, protocol.into()))
+    }
+}
+
+impl Decode for PppHeader {
+    type Iterm = PppHeader;
+    fn decode(input: &[u8]) -> IResult<&[u8], PppHeader> {
+        let (input, address) = number::streaming::be_u8(input)?;
+        let (input, control) = number::streaming::be_u8(input)?;
+        let (input, protocol) = PppProtocol::decode(input)?;
+        Ok((
+            input,
+            PppHeader {
+                address,
+                control,
+                protocol,
+            },
+        ))
+    }
+}
+
+/******************************************************************************
+ * TEST
+ ******************************************************************************/
+
+#[cfg(test)]
+mod tests {
+    use super::PppHeader;
+    use super::PppProtocol;
+    use crate::protocol::codec::Decode;
+    const LAST_SLICE: &'static [u8] = &[0xff];
+
+    #[test]
+    fn ppp_header_decode() {
+        /*
+         * Point-to-Point Protocol
+         *     Address: 0xff
+         *     Control: 0x03
+         *     Protocol: Link Control Protocol (0xc021)
+         */
+
+        let bytes = [0xff, 0x03, 0xc0, 0x21, 0xff /* Payload */];
+
+        let expectation = PppHeader {
+            address: 0xff,
+            control: 0x03,
+            protocol: PppProtocol::LCP,
+        };
+
+        assert_eq!(PppHeader::decode(&bytes), Ok((LAST_SLICE, expectation)));
+
+        // example
+        let result = PppHeader::decode(&bytes);
+        if let Ok((payload, header)) = result {
+            println!("return: {:?}, payload: {}", header, payload.len());
+        } else {
+            println!("return: Incomplete data");
+        }
+    }
+}