Remove the use of anyhow in netlink-packet-core

Author: hch12907

src/buffer.rs

@@ -1,9 +1,8 @@
 // SPDX-License-Identifier: MIT
 
 use byteorder::{ByteOrder, NativeEndian};
-use netlink_packet_utils::DecodeError;
 
-use crate::{Field, Rest};
+use crate::{CoreError, Field, Rest};
 
 const LENGTH: Field = 0..4;
 const MESSAGE_TYPE: Field = 4..6;
@@ -156,33 +155,20 @@ impl<T: AsRef<[u8]>> NetlinkBuffer<T> {
     ///     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
     /// assert!(NetlinkBuffer::new_checked(&BYTES[..]).is_err());
     /// ```
-    pub fn new_checked(buffer: T) -> Result<NetlinkBuffer<T>, DecodeError> {
+    pub fn new_checked(buffer: T) -> Result<NetlinkBuffer<T>, CoreError> {
         let packet = Self::new(buffer);
         packet.check_buffer_length()?;
         Ok(packet)
     }
 
-    fn check_buffer_length(&self) -> Result<(), DecodeError> {
+    fn check_buffer_length(&self) -> Result<(), CoreError> {
         let len = self.buffer.as_ref().len();
         if len < PORT_NUMBER.end {
-            Err(format!(
-                "invalid netlink buffer: length is {} but netlink packets are at least {} bytes",
-                len, PORT_NUMBER.end
-            )
-            .into())
+            Err(CoreError::PacketTooShort { received: len, expected: PORT_NUMBER.end })
         } else if len < self.length() as usize {
-            Err(format!(
-                "invalid netlink buffer: length field says {} the buffer is {} bytes long",
-                self.length(),
-                len
-            )
-            .into())
+            Err(CoreError::NonmatchingLength { expected: self.length(), actual: len })
         } else if (self.length() as usize) < PORT_NUMBER.end {
-            Err(format!(
-                "invalid netlink buffer: length field says {} but netlink packets are at least {} bytes",
-                self.length(),
-                len
-            ).into())
+            Err(CoreError::InvalidLength { given: self.length(), at_least: len })
         } else {
             Ok(())
         }

src/done.rs

@@ -3,9 +3,8 @@
 use std::mem::size_of;
 
 use byteorder::{ByteOrder, NativeEndian};
-use netlink_packet_utils::DecodeError;
 
-use crate::{Emitable, Field, Parseable, Rest};
+use crate::{CoreError, Emitable, Field, Parseable, Rest};
 
 const CODE: Field = 0..4;
 const EXTENDED_ACK: Rest = 4..;
@@ -27,20 +26,16 @@ impl<T: AsRef<[u8]>> DoneBuffer<T> {
         self.buffer
     }
 
-    pub fn new_checked(buffer: T) -> Result<Self, DecodeError> {
+    pub fn new_checked(buffer: T) -> Result<Self, CoreError> {
         let packet = Self::new(buffer);
         packet.check_buffer_length()?;
         Ok(packet)
     }
 
-    fn check_buffer_length(&self) -> Result<(), DecodeError> {
+    fn check_buffer_length(&self) -> Result<(), CoreError> {
         let len = self.buffer.as_ref().len();
         if len < DONE_HEADER_LEN {
-            Err(format!(
-                "invalid DoneBuffer: length is {len} but DoneBuffer are \
-                at least {DONE_HEADER_LEN} bytes"
-            )
-            .into())
+            Err(CoreError::InvalidDoneBuffer { received: len })
         } else {
             Ok(())
         }
@@ -100,7 +95,9 @@ impl Emitable for DoneMessage {
 impl<'buffer, T: AsRef<[u8]> + 'buffer> Parseable<DoneBuffer<&'buffer T>>
     for DoneMessage
 {
-    fn parse(buf: &DoneBuffer<&'buffer T>) -> Result<DoneMessage, DecodeError> {
+    type Error = CoreError;
+
+    fn parse(buf: &DoneBuffer<&'buffer T>) -> Result<DoneMessage, Self::Error> {
         Ok(DoneMessage {
             code: buf.code(),
             extended_ack: buf.extended_ack().to_vec(),

src/error.rs

@@ -3,9 +3,8 @@
 use std::{fmt, io, mem::size_of, num::NonZeroI32};
 
 use byteorder::{ByteOrder, NativeEndian};
-use netlink_packet_utils::DecodeError;
 
-use crate::{Emitable, Field, Parseable, Rest};
+use crate::{CoreError, Emitable, Field, Parseable, Rest};
 
 const CODE: Field = 0..4;
 const PAYLOAD: Rest = 4..;
@@ -27,20 +26,16 @@ impl<T: AsRef<[u8]>> ErrorBuffer<T> {
         self.buffer
     }
 
-    pub fn new_checked(buffer: T) -> Result<Self, DecodeError> {
+    pub fn new_checked(buffer: T) -> Result<Self, CoreError> {
         let packet = Self::new(buffer);
         packet.check_buffer_length()?;
         Ok(packet)
     }
 
-    fn check_buffer_length(&self) -> Result<(), DecodeError> {
+    fn check_buffer_length(&self) -> Result<(), CoreError> {
         let len = self.buffer.as_ref().len();
         if len < ERROR_HEADER_LEN {
-            Err(format!(
-                "invalid ErrorBuffer: length is {len} but ErrorBuffer are \
-                at least {ERROR_HEADER_LEN} bytes"
-            )
-            .into())
+            Err(CoreError::InvalidErrorBuffer { received: len })
         } else {
             Ok(())
         }
@@ -118,9 +113,11 @@ impl Emitable for ErrorMessage {
 impl<'buffer, T: AsRef<[u8]> + 'buffer> Parseable<ErrorBuffer<&'buffer T>>
     for ErrorMessage
 {
+    type Error = CoreError;
+
     fn parse(
         buf: &ErrorBuffer<&'buffer T>,
-    ) -> Result<ErrorMessage, DecodeError> {
+    ) -> Result<ErrorMessage, Self::Error> {
         // FIXME: The payload of an error is basically a truncated packet, which
         // requires custom logic to parse correctly. For now we just
         // return it as a Vec<u8> let header: NetlinkHeader = {

src/header.rs

@@ -1,7 +1,6 @@
 // SPDX-License-Identifier: MIT
 
-use netlink_packet_utils::DecodeError;
-
+use crate::CoreError;
 use crate::{buffer::NETLINK_HEADER_LEN, Emitable, NetlinkBuffer, Parseable};
 
 /// A Netlink header representation. A netlink header has the following
@@ -57,7 +56,9 @@ impl Emitable for NetlinkHeader {
 impl<'a, T: AsRef<[u8]> + ?Sized> Parseable<NetlinkBuffer<&'a T>>
     for NetlinkHeader
 {
-    fn parse(buf: &NetlinkBuffer<&'a T>) -> Result<NetlinkHeader, DecodeError> {
+    type Error = CoreError;
+
+    fn parse(buf: &NetlinkBuffer<&'a T>) -> Result<NetlinkHeader, Self::Error> {
         Ok(NetlinkHeader {
             length: buf.length(),
             message_type: buf.message_type(),

src/lib.rs

@@ -270,3 +270,51 @@ pub use self::constants::*;
 
 pub(crate) use self::utils::traits::*;
 pub(crate) use netlink_packet_utils as utils;
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum CoreError {
+    #[error("invalid netlink buffer: length is {received} but netlink packets are at least {expected} bytes")]
+    PacketTooShort { received: usize, expected: usize },
+
+    #[error("invalid netlink buffer: length field says {expected} the buffer is {actual} bytes long")]
+    NonmatchingLength { expected: u32, actual: usize },
+
+    #[error("invalid netlink buffer: length field says {given} but netlink packets are at least {at_least} bytes")]
+    InvalidLength { given: u32, at_least: usize },
+
+    #[error(
+        "invalid ErrorBuffer: length is {received}, expected at least 4 bytes"
+    )]
+    InvalidErrorBuffer { received: usize },
+
+    #[error(
+        "invalid DoneBuffer: length is {received}, expected at least 4 bytes"
+    )]
+    InvalidDoneBuffer { received: usize },
+
+    #[error("invalid Netlink header")]
+    InvalidHeader {
+        #[source]
+        due_to: Box<Self>,
+    },
+
+    #[error("invalid Netlink message of type NLMSG_ERROR")]
+    InvalidErrorMsg {
+        #[source]
+        due_to: Box<Self>,
+    },
+
+    #[error("invalid Netlink message of type NLMSG_DONE")]
+    InvalidDoneMsg {
+        #[source]
+        due_to: Box<Self>,
+    },
+
+    #[error("failed to parse the netlink message, of type {message_type}")]
+    ParseFailure {
+        message_type: u16,
+        #[source]
+        due_to: Box<dyn std::error::Error>,
+    },
+}

src/message.rs

@@ -2,12 +2,9 @@
 
 use std::fmt::Debug;
 
-use anyhow::Context;
-use netlink_packet_utils::DecodeError;
-
 use crate::{
     payload::{NLMSG_DONE, NLMSG_ERROR, NLMSG_NOOP, NLMSG_OVERRUN},
-    DoneBuffer, DoneMessage, Emitable, ErrorBuffer, ErrorMessage,
+    CoreError, DoneBuffer, DoneMessage, Emitable, ErrorBuffer, ErrorMessage,
     NetlinkBuffer, NetlinkDeserializable, NetlinkHeader, NetlinkPayload,
     NetlinkSerializable, Parseable,
 };
@@ -39,7 +36,7 @@ where
     I: NetlinkDeserializable,
 {
     /// Parse the given buffer as a netlink message
-    pub fn deserialize(buffer: &[u8]) -> Result<Self, DecodeError> {
+    pub fn deserialize(buffer: &[u8]) -> Result<Self, CoreError> {
         let netlink_buffer = NetlinkBuffer::new_checked(&buffer)?;
         <Self as Parseable<NetlinkBuffer<&&[u8]>>>::parse(&netlink_buffer)
     }
@@ -88,33 +85,43 @@ where
     B: AsRef<[u8]> + 'buffer,
     I: NetlinkDeserializable,
 {
-    fn parse(buf: &NetlinkBuffer<&'buffer B>) -> Result<Self, DecodeError> {
+    type Error = CoreError;
+
+    fn parse(buf: &NetlinkBuffer<&'buffer B>) -> Result<Self, Self::Error> {
         use self::NetlinkPayload::*;
 
         let header =
             <NetlinkHeader as Parseable<NetlinkBuffer<&'buffer B>>>::parse(buf)
-                .context("failed to parse netlink header")?;
+                .map_err(|e| CoreError::InvalidHeader { due_to: e.into() })?;
 
         let bytes = buf.payload();
         let payload = match header.message_type {
             NLMSG_ERROR => {
                 let msg = ErrorBuffer::new_checked(&bytes)
                     .and_then(|buf| ErrorMessage::parse(&buf))
-                    .context("failed to parse NLMSG_ERROR")?;
+                    .map_err(|e| CoreError::InvalidErrorMsg {
+                        due_to: e.into(),
+                    })?;
                 Error(msg)
             }
             NLMSG_NOOP => Noop,
             NLMSG_DONE => {
                 let msg = DoneBuffer::new_checked(&bytes)
                     .and_then(|buf| DoneMessage::parse(&buf))
-                    .context("failed to parse NLMSG_DONE")?;
+                    .map_err(|e| CoreError::InvalidDoneMsg {
+                        due_to: e.into(),
+                    })?;
                 Done(msg)
             }
             NLMSG_OVERRUN => Overrun(bytes.to_vec()),
             message_type => {
-                let inner_msg = I::deserialize(&header, bytes).context(
-                    format!("Failed to parse message with type {message_type}"),
-                )?;
+                let inner_msg =
+                    I::deserialize(&header, bytes).map_err(|e| {
+                        CoreError::ParseFailure {
+                            message_type,
+                            due_to: e.into(),
+                        }
+                    })?;
                 InnerMessage(inner_msg)
             }
         };