Enable PacketBuilder in no_std (alloc/slice) while preserving std API

etherparse/Cargo.toml

@@ -21,7 +21,8 @@ rust-version = "1.83.0"
 
 [features]
 default = ["std"]
-std = ["arrayvec/std"]
+alloc = []
+std = ["alloc", "arrayvec/std"]
 
 [dependencies]
 arrayvec = { version = "0.7.2", default-features = false }

etherparse/src/err/packet/build_slice_write_error.rs

@@ -0,0 +1,110 @@
+use crate::err::{ipv4_exts, ipv6_exts, SliceWriteSpaceError, ValueTooBigError};
+
+/// Error while serializing a packet into a byte slice.
+#[derive(Clone, Debug, Eq, PartialEq, Hash)]
+pub enum BuildSliceWriteError {
+    /// Not enough space is available in the target slice.
+    /// Contains the minimum required length.
+    Space(usize),
+
+    /// Error if the length of the payload is too
+    /// big to be representable by the length fields.
+    PayloadLen(ValueTooBigError<usize>),
+
+    /// Error if the IPv4 extensions can not be serialized
+    /// because of internal consistency errors (i.e. a header
+    /// is never).
+    Ipv4Exts(ipv4_exts::ExtsWalkError),
+
+    /// Error if the IPv6 extensions can not be serialized
+    /// because of internal consistency errors.
+    Ipv6Exts(ipv6_exts::ExtsWalkError),
+
+    /// Error if ICMPv6 is packaged in an IPv4 packet (it is undefined
+    /// how to calculate the checksum).
+    Icmpv6InIpv4,
+
+    /// Address size defined in the ARP header does not match the actual size.
+    ArpHeaderNotMatch,
+}
+
+impl From<ValueTooBigError<usize>> for BuildSliceWriteError {
+    fn from(value: ValueTooBigError<usize>) -> Self {
+        BuildSliceWriteError::PayloadLen(value)
+    }
+}
+
+impl From<SliceWriteSpaceError> for BuildSliceWriteError {
+    fn from(value: SliceWriteSpaceError) -> Self {
+        BuildSliceWriteError::Space(value.required_len)
+    }
+}
+
+impl From<super::TransportChecksumError> for BuildSliceWriteError {
+    fn from(value: super::TransportChecksumError) -> Self {
+        match value {
+            super::TransportChecksumError::PayloadLen(err) => BuildSliceWriteError::PayloadLen(err),
+            super::TransportChecksumError::Icmpv6InIpv4 => BuildSliceWriteError::Icmpv6InIpv4,
+        }
+    }
+}
+
+impl From<crate::WriteError<SliceWriteSpaceError, ipv4_exts::ExtsWalkError>>
+    for BuildSliceWriteError
+{
+    fn from(value: crate::WriteError<SliceWriteSpaceError, ipv4_exts::ExtsWalkError>) -> Self {
+        match value {
+            crate::WriteError::Io(err) => BuildSliceWriteError::Space(err.required_len),
+            crate::WriteError::Content(err) => BuildSliceWriteError::Ipv4Exts(err),
+        }
+    }
+}
+
+impl From<crate::WriteError<SliceWriteSpaceError, ipv6_exts::ExtsWalkError>>
+    for BuildSliceWriteError
+{
+    fn from(value: crate::WriteError<SliceWriteSpaceError, ipv6_exts::ExtsWalkError>) -> Self {
+        match value {
+            crate::WriteError::Io(err) => BuildSliceWriteError::Space(err.required_len),
+            crate::WriteError::Content(err) => BuildSliceWriteError::Ipv6Exts(err),
+        }
+    }
+}
+
+impl core::fmt::Display for BuildSliceWriteError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        use BuildSliceWriteError::*;
+        match self {
+            Space(required_len) => write!(
+                f,
+                "Not enough space to write packet to slice. Needed {} byte(s).",
+                required_len
+            ),
+            PayloadLen(err) => err.fmt(f),
+            Ipv4Exts(err) => err.fmt(f),
+            Ipv6Exts(err) => err.fmt(f),
+            ArpHeaderNotMatch => write!(
+                f,
+                "address size defined in the ARP header does not match the actual size"
+            ),
+            Icmpv6InIpv4 => write!(
+                f,
+                "Error: ICMPv6 can not be combined with an IPv4 headers (checksum can not be calculated)."
+            ),
+        }
+    }
+}
+
+impl core::error::Error for BuildSliceWriteError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
+        use BuildSliceWriteError::*;
+        match self {
+            Space(_) => None,
+            PayloadLen(err) => Some(err),
+            Ipv4Exts(err) => Some(err),
+            Ipv6Exts(err) => Some(err),
+            Icmpv6InIpv4 => None,
+            ArpHeaderNotMatch => None,
+        }
+    }
+}

etherparse/src/err/packet/build_vec_write_error.rs

@@ -0,0 +1,97 @@
+use crate::err::{ipv4_exts, ipv6_exts, ValueTooBigError};
+use core::convert::Infallible;
+
+/// Error while serializing a packet into a [`alloc::vec::Vec`].
+#[derive(Clone, Debug, Eq, PartialEq, Hash)]
+pub enum BuildVecWriteError {
+    /// Error if the length of the payload is too
+    /// big to be representable by the length fields.
+    PayloadLen(ValueTooBigError<usize>),
+
+    /// Error if the IPv4 extensions can not be serialized
+    /// because of internal consistency errors (i.e. a header
+    /// is never).
+    Ipv4Exts(ipv4_exts::ExtsWalkError),
+
+    /// Error if the IPv6 extensions can not be serialized
+    /// because of internal consistency errors.
+    Ipv6Exts(ipv6_exts::ExtsWalkError),
+
+    /// Error if ICMPv6 is packaged in an IPv4 packet (it is undefined
+    /// how to calculate the checksum).
+    Icmpv6InIpv4,
+
+    /// Address size defined in the ARP header does not match the actual size.
+    ArpHeaderNotMatch,
+}
+
+impl From<Infallible> for BuildVecWriteError {
+    fn from(value: Infallible) -> Self {
+        match value {}
+    }
+}
+
+impl From<ValueTooBigError<usize>> for BuildVecWriteError {
+    fn from(value: ValueTooBigError<usize>) -> Self {
+        BuildVecWriteError::PayloadLen(value)
+    }
+}
+
+impl From<super::TransportChecksumError> for BuildVecWriteError {
+    fn from(value: super::TransportChecksumError) -> Self {
+        match value {
+            super::TransportChecksumError::PayloadLen(err) => BuildVecWriteError::PayloadLen(err),
+            super::TransportChecksumError::Icmpv6InIpv4 => BuildVecWriteError::Icmpv6InIpv4,
+        }
+    }
+}
+
+impl From<crate::WriteError<Infallible, ipv4_exts::ExtsWalkError>> for BuildVecWriteError {
+    fn from(value: crate::WriteError<Infallible, ipv4_exts::ExtsWalkError>) -> Self {
+        match value {
+            crate::WriteError::Io(err) => match err {},
+            crate::WriteError::Content(err) => BuildVecWriteError::Ipv4Exts(err),
+        }
+    }
+}
+
+impl From<crate::WriteError<Infallible, ipv6_exts::ExtsWalkError>> for BuildVecWriteError {
+    fn from(value: crate::WriteError<Infallible, ipv6_exts::ExtsWalkError>) -> Self {
+        match value {
+            crate::WriteError::Io(err) => match err {},
+            crate::WriteError::Content(err) => BuildVecWriteError::Ipv6Exts(err),
+        }
+    }
+}
+
+impl core::fmt::Display for BuildVecWriteError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        use BuildVecWriteError::*;
+        match self {
+            PayloadLen(err) => err.fmt(f),
+            Ipv4Exts(err) => err.fmt(f),
+            Ipv6Exts(err) => err.fmt(f),
+            ArpHeaderNotMatch => write!(
+                f,
+                "address size defined in the ARP header does not match the actual size"
+            ),
+            Icmpv6InIpv4 => write!(
+                f,
+                "Error: ICMPv6 can not be combined with an IPv4 headers (checksum can not be calculated)."
+            ),
+        }
+    }
+}
+
+impl core::error::Error for BuildVecWriteError {
+    fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
+        use BuildVecWriteError::*;
+        match self {
+            PayloadLen(err) => Some(err),
+            Ipv4Exts(err) => Some(err),
+            Ipv6Exts(err) => Some(err),
+            Icmpv6InIpv4 => None,
+            ArpHeaderNotMatch => None,
+        }
+    }
+}

etherparse/src/err/packet/build_write_error.rs

@@ -105,6 +105,50 @@ impl core::error::Error for BuildWriteError {
     }
 }
 
+#[cfg(feature = "std")]
+impl From<std::io::Error> for BuildWriteError {
+    fn from(value: std::io::Error) -> Self {
+        BuildWriteError::Io(value)
+    }
+}
+
+#[cfg(feature = "std")]
+impl From<ValueTooBigError<usize>> for BuildWriteError {
+    fn from(value: ValueTooBigError<usize>) -> Self {
+        BuildWriteError::PayloadLen(value)
+    }
+}
+
+#[cfg(feature = "std")]
+impl From<super::TransportChecksumError> for BuildWriteError {
+    fn from(value: super::TransportChecksumError) -> Self {
+        match value {
+            super::TransportChecksumError::PayloadLen(err) => BuildWriteError::PayloadLen(err),
+            super::TransportChecksumError::Icmpv6InIpv4 => BuildWriteError::Icmpv6InIpv4,
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl From<crate::WriteError<std::io::Error, ipv4_exts::ExtsWalkError>> for BuildWriteError {
+    fn from(value: crate::WriteError<std::io::Error, ipv4_exts::ExtsWalkError>) -> Self {
+        match value {
+            crate::WriteError::Io(err) => BuildWriteError::Io(err),
+            crate::WriteError::Content(err) => BuildWriteError::Ipv4Exts(err),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl From<crate::WriteError<std::io::Error, ipv6_exts::ExtsWalkError>> for BuildWriteError {
+    fn from(value: crate::WriteError<std::io::Error, ipv6_exts::ExtsWalkError>) -> Self {
+        match value {
+            crate::WriteError::Io(err) => BuildWriteError::Io(err),
+            crate::WriteError::Content(err) => BuildWriteError::Ipv6Exts(err),
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::{BuildWriteError::*, *};

etherparse/src/err/packet/mod.rs

@@ -3,6 +3,14 @@ mod build_write_error;
 #[cfg(feature = "std")]
 pub use build_write_error::*;
 
+#[cfg(feature = "alloc")]
+mod build_vec_write_error;
+#[cfg(feature = "alloc")]
+pub use build_vec_write_error::*;
+
+mod build_slice_write_error;
+pub use build_slice_write_error::*;
+
 mod slice_error;
 pub use slice_error::*;
 

etherparse/src/lib.rs

@@ -303,7 +303,7 @@
 // for docs.rs
 #![cfg_attr(docsrs, feature(doc_cfg))]
 
-#[cfg(test)]
+#[cfg(any(feature = "alloc", test))]
 extern crate alloc;
 #[cfg(test)]
 extern crate proptest;
@@ -343,6 +343,9 @@ mod compositions_tests;
 mod helpers;
 pub(crate) use helpers::*;
 
+mod writer;
+pub(crate) use writer::*;
+
 mod lax_packet_headers;
 pub use lax_packet_headers::*;
 
@@ -358,9 +361,7 @@ pub(crate) use lax_sliced_packet_cursor::*;
 mod len_source;
 pub use len_source::*;
 
-#[cfg(feature = "std")]
 mod packet_builder;
-#[cfg(feature = "std")]
 pub use crate::packet_builder::*;
 
 mod packet_headers;

etherparse/src/link/single_vlan_header_slice.rs

@@ -43,6 +43,7 @@ impl<'a> SingleVlanHeaderSlice<'a> {
     /// The caller must ensured that the given slice has the length of
     /// [`SingleVlanHeader::LEN`]
     #[inline]
+    #[cfg(feature = "std")]
     pub(crate) unsafe fn from_slice_unchecked(slice: &[u8]) -> SingleVlanHeaderSlice {
         SingleVlanHeaderSlice { slice }
     }

etherparse/src/net/ipv4_exts.rs

@@ -160,21 +160,19 @@ impl Ipv4Extensions {
     }
 
     /// Write the extensions to the writer.
-    #[cfg(feature = "std")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
-    pub fn write<T: std::io::Write + Sized>(
+    pub(crate) fn write_internal<T: CoreWrite + ?Sized>(
         &self,
         writer: &mut T,
         start_ip_number: IpNumber,
-    ) -> Result<(), err::ipv4_exts::HeaderWriteError> {
-        use err::ipv4_exts::{ExtsWalkError::*, HeaderWriteError::*};
+    ) -> Result<(), WriteError<T::Error, err::ipv4_exts::ExtsWalkError>> {
+        use err::ipv4_exts::ExtsWalkError::*;
         use ip_number::*;
         match self.auth {
             Some(ref header) => {
                 if AUTH == start_ip_number {
-                    header.write(writer).map_err(Io)
+                    writer.write_all(&header.to_bytes()).map_err(WriteError::Io)
                 } else {
-                    Err(Content(ExtNotReferenced {
+                    Err(WriteError::Content(ExtNotReferenced {
                         missing_ext: IpNumber::AUTHENTICATION_HEADER,
                     }))
                 }
@@ -183,6 +181,21 @@ impl Ipv4Extensions {
         }
     }
 
+    /// Write the extensions 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,
+        start_ip_number: IpNumber,
+    ) -> Result<(), err::ipv4_exts::HeaderWriteError> {
+        self.write_internal(&mut IoWriter(writer), start_ip_number)
+            .map_err(|err| match err {
+                WriteError::Io(err) => err::ipv4_exts::HeaderWriteError::Io(err),
+                WriteError::Content(err) => err::ipv4_exts::HeaderWriteError::Content(err),
+            })
+    }
+
     ///Length of the all present headers in bytes.
     pub fn header_len(&self) -> usize {
         if let Some(ref header) = self.auth {