Add RFC4443 ICMPv6 payload slice support

etherparse/src/transport/icmpv6/icmpv6_payload/mod.rs

@@ -45,10 +45,7 @@ impl Icmpv6Payload {
     /// Write the fixed payload bytes to the writer.
     #[cfg(feature = "std")]
     #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
-    pub fn write<T: std::io::Write + Sized>(
-        &self,
-        writer: &mut T,
-    ) -> Result<(), std::io::Error> {
+    pub fn write<T: std::io::Write + Sized>(&self, writer: &mut T) -> Result<(), std::io::Error> {
         match self {
             Icmpv6Payload::RouterSolicitation(value) => writer.write_all(&value.to_bytes()),
             Icmpv6Payload::RouterAdvertisement(value) => writer.write_all(&value.to_bytes()),
@@ -62,7 +59,6 @@ impl Icmpv6Payload {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use alloc::format;
     use proptest::prelude::*;
 
     #[test]

etherparse/src/transport/icmpv6/icmpv6_payload_slice/destination_unreachable_payload_slice.rs

@@ -0,0 +1,55 @@
+use crate::{err, LaxIpSlice};
+
+/// Borrowed payload of a Destination Unreachable message (RFC 4443, Section 3.1).
+///
+/// The full packet layout is:
+/// ```text
+///  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
+/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/// |     Type      |     Code      |          Checksum             |
+/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/// |                             Unused                            |
+/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/// |                    As much of invoking packet                 |
+/// +                as possible without the ICMPv6 packet          +
+/// |                exceeding the minimum IPv6 MTU [IPv6]          |
+/// ```
+///
+/// In this crate, `Type`, `Code`, and `Unused` are represented by
+/// [`crate::Icmpv6Type::DestinationUnreachable`]. This slice represents the
+/// invoking packet bytes after that fixed part.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct DestinationUnreachablePayloadSlice<'a> {
+    slice: &'a [u8],
+}
+
+impl<'a> DestinationUnreachablePayloadSlice<'a> {
+    /// Creates a payload slice from the bytes after the ICMPv6 header.
+    pub fn from_slice(slice: &'a [u8]) -> Result<Self, err::LenError> {
+        Ok(Self { slice })
+    }
+
+    /// Returns the full payload slice.
+    pub fn slice(&self) -> &'a [u8] {
+        self.slice
+    }
+
+    /// Returns the invoking packet bytes carried by the message.
+    pub fn invoking_packet(&self) -> &'a [u8] {
+        self.slice
+    }
+
+    /// Decodes the invoking packet bytes as a lax IP slice.
+    pub fn as_lax_ip_slice(
+        &self,
+    ) -> Result<
+        (
+            LaxIpSlice<'a>,
+            Option<(err::ipv6_exts::HeaderSliceError, err::Layer)>,
+        ),
+        err::ip::LaxHeaderSliceError,
+    > {
+        LaxIpSlice::from_slice(self.invoking_packet())
+    }
+}

etherparse/src/transport/icmpv6/icmpv6_payload_slice/echo_reply_payload_slice.rs

@@ -0,0 +1,41 @@
+use crate::err;
+
+/// Borrowed payload of an Echo Reply message (RFC 4443, Section 4.2).
+///
+/// The full packet layout is:
+/// ```text
+///  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
+/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/// |     Type      |     Code      |          Checksum             |
+/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/// |           Identifier          |        Sequence Number        |
+/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/// |     Data ...
+/// +-+-+-+-+-+-+-+-+-
+/// ```
+///
+/// In this crate, `Type`, `Code`, `Identifier`, and `Sequence Number` are
+/// represented by [`crate::Icmpv6Type::EchoReply`]. This slice represents
+/// the echoed data after that fixed part.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct EchoReplyPayloadSlice<'a> {
+    slice: &'a [u8],
+}
+
+impl<'a> EchoReplyPayloadSlice<'a> {
+    /// Creates a payload slice from the bytes after the ICMPv6 header.
+    pub fn from_slice(slice: &'a [u8]) -> Result<Self, err::LenError> {
+        Ok(Self { slice })
+    }
+
+    /// Returns the full payload slice.
+    pub fn slice(&self) -> &'a [u8] {
+        self.slice
+    }
+
+    /// Returns the echoed data bytes.
+    pub fn data(&self) -> &'a [u8] {
+        self.slice
+    }
+}

etherparse/src/transport/icmpv6/icmpv6_payload_slice/echo_request_payload_slice.rs

@@ -0,0 +1,41 @@
+use crate::err;
+
+/// Borrowed payload of an Echo Request message (RFC 4443, Section 4.1).
+///
+/// The full packet layout is:
+/// ```text
+///  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
+/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/// |     Type      |     Code      |          Checksum             |
+/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/// |           Identifier          |        Sequence Number        |
+/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/// |     Data ...
+/// +-+-+-+-+-+-+-+-+-
+/// ```
+///
+/// In this crate, `Type`, `Code`, `Identifier`, and `Sequence Number` are
+/// represented by [`crate::Icmpv6Type::EchoRequest`]. This slice represents
+/// the echoed data after that fixed part.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct EchoRequestPayloadSlice<'a> {
+    slice: &'a [u8],
+}
+
+impl<'a> EchoRequestPayloadSlice<'a> {
+    /// Creates a payload slice from the bytes after the ICMPv6 header.
+    pub fn from_slice(slice: &'a [u8]) -> Result<Self, err::LenError> {
+        Ok(Self { slice })
+    }
+
+    /// Returns the full payload slice.
+    pub fn slice(&self) -> &'a [u8] {
+        self.slice
+    }
+
+    /// Returns the echoed data bytes.
+    pub fn data(&self) -> &'a [u8] {
+        self.slice
+    }
+}