TSG-12768 使用RUST解析IPv6 Header

1 files changed, 161 insertions, 0 deletions

diff --git a/src/protocol/ipv6.rs b/src/protocol/ipv6.rs
new file mode 100644
index 0000000..8b04954
--- /dev/null
+++ b/src/protocol/ipv6.rs
@@ -0,0 +1,161 @@
+use crate::protocol::ip::{self, IPProtocol};
+use nom::bits;
+use nom::bytes;
+use nom::error::Error;
+use nom::number;
+use nom::sequence;
+use nom::IResult;
+use std::convert::TryFrom;
+use std::net::Ipv6Addr;
+
+/******************************************************************************
+ * Struct
+ ******************************************************************************/
+
+/*
+ * IPv6 Header Format
+ *
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |Version| Traffic Class |           Flow Label                  |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |         Payload Length        |  Next Header  |   Hop Limit   |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |                                                               |
+ *  +                                                               +
+ *  |                                                               |
+ *  +                         Source Address                        +
+ *  |                                                               |
+ *  +                                                               +
+ *  |                                                               |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |                                                               |
+ *  +                                                               +
+ *  |                                                               |
+ *  +                      Destination Address                      +
+ *  |                                                               |
+ *  +                                                               +
+ *  |                                                               |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct IPv6Header {
+    pub version: u8,     // 4 bit
+    pub dsc: u8,         // Differentiated Services Codepoint: 6 bit
+    pub ecn: u8,         // Explicit Congestion Notification:  2 bit
+    pub flow_label: u32, // 20 bit
+    pub length: u16,
+    pub next_header: IPProtocol,
+    pub hop_limit: u8,
+    pub source_addr: Ipv6Addr,
+    pub dest_addr: Ipv6Addr,
+}
+
+/******************************************************************************
+ * Parse
+ ******************************************************************************/
+
+fn parse_byte_to_half(input: &[u8]) -> IResult<&[u8], (u8, u8)> {
+    bits::bits::<_, _, Error<_>, _, _>(sequence::pair(
+        bits::streaming::take(4u8),
+        bits::streaming::take(4u8),
+    ))(input)
+}
+
+fn parse_ipv6_address(input: &[u8]) -> IResult<&[u8], Ipv6Addr> {
+    let (input, ipv6) = bytes::streaming::take(16u8)(input)?;
+
+    Ok((input, Ipv6Addr::from(<[u8; 16]>::try_from(ipv6).unwrap())))
+}
+
+pub fn parse_ipv6(input: &[u8]) -> IResult<&[u8], IPv6Header> {
+    let (input, ver_tc) = parse_byte_to_half(input)?;
+    let (input, tc_fl) = parse_byte_to_half(input)?;
+    let (input, fl): (_, u32) =
+        bits::bits::<_, _, Error<_>, _, _>(bits::streaming::take(16u8))(input)?;
+    let (input, length) = number::streaming::be_u16(input)?;
+    let (input, next_header) = ip::protocol(input)?;
+    let (input, hop_limit) = number::streaming::be_u8(input)?;
+    let (input, source_addr) = parse_ipv6_address(input)?;
+    let (input, dest_addr) = parse_ipv6_address(input)?;
+
+    Ok((
+        input,
+        IPv6Header {
+            version: ver_tc.0,
+            dsc: (ver_tc.1 << 2) + ((tc_fl.0 & 0b1100) >> 2),
+            ecn: tc_fl.0 & 0b11,
+            flow_label: (u32::from(tc_fl.1) << 16) + fl,
+            length,
+            next_header,
+            hop_limit,
+            source_addr,
+            dest_addr,
+        },
+    ))
+}
+
+/******************************************************************************
+ * TEST
+ ******************************************************************************/
+
+#[cfg(test)]
+mod tests {
+    use super::parse_ipv6;
+    use super::IPv6Header;
+    use crate::ip::IPProtocol;
+    use std::net::Ipv6Addr;
+
+    const LAST_SLICE: &'static [u8] = &[0xff];
+
+    #[test]
+    fn parse_ipv6_works() {
+        /*
+         * Internet Protocol Version 6, Src: 2409:8034:4025::50:a31, Dst: 2409:8034:4040:5301::204
+         *     0110 .... = Version: 6
+         *     .... 0000 0000 .... .... .... .... .... = Traffic Class: 0x00 (DSCP: CS0, ECN: Not-ECT)
+         *         .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
+         *         .... .... ..00 .... .... .... .... .... = Explicit Congestion Notification: Not ECN-Capable Transport (0)
+         *     .... 0000 0000 0000 0000 0000 = Flow Label: 0x00000
+         *     Payload Length: 1416
+         *     Next Header: UDP (17)
+         *     Hop Limit: 252
+         *     Source Address: 2409:8034:4025::50:a31
+         *     Destination Address: 2409:8034:4040:5301::204
+         */
+
+        let bytes = [
+            0x60, /* Version and Partial Differentiated Services Codepoint */
+            0x00, /* Partial Differentiated Services Codepoint and Explicit Congestion Notification and Partial Flow Label */
+            0x00, 0x00, /* Partial Flow Label */
+            0x05, 0x88, /* Payload Length */
+            0x11, /* Next Header */
+            0xfc, /* Hop Limit */
+            0x24, 0x09, 0x80, 0x34, 0x40, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x50,
+            0x0a, 0x31, /* Source Address */
+            0x24, 0x09, 0x80, 0x34, 0x40, 0x40, 0x53, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x02, 0x04, /* Destination Address */
+            0xff, /* Payload */
+        ];
+
+        let expectation = IPv6Header {
+            version: 6,
+            dsc: 0,
+            ecn: 0,
+            flow_label: 0,
+            length: 1416,
+            next_header: IPProtocol::UDP,
+            hop_limit: 252,
+            source_addr: Ipv6Addr::new(
+                0x2409, 0x8034, 0x4025, 0x0000, 0x0000, 0x0000, 0x0050, 0x0a31,
+            ),
+            dest_addr: Ipv6Addr::new(
+                0x2409, 0x8034, 0x4040, 0x5301, 0x0000, 0x0000, 0x0000, 0x0204,
+            ),
+        };
+
+        assert_eq!(parse_ipv6(&bytes), Ok((LAST_SLICE, expectation)));
+    }
+}