Cleanup round 2

Author: daniel-noland

src/tc/filters/cls_flower.rs

@@ -3,7 +3,7 @@
 /// flower filter
 use std::net::{Ipv4Addr, Ipv6Addr};
 
-use anyhow::Context;
+use anyhow::{Context, Error};
 use byteorder::{BigEndian, ByteOrder, NativeEndian};
 use netlink_packet_utils::nla::{NlasIterator, NLA_F_NESTED};
 use netlink_packet_utils::parsers::{
@@ -814,19 +814,28 @@ impl Nla for FlowerAction {
 #[derive(Debug, PartialEq, Eq, Clone)]
 struct FlowerActionList(Vec<FlowerAction>);
 
-impl From<&Vec<TcAction>> for FlowerActionList {
-    fn from(actions: &Vec<TcAction>) -> Self {
-        Self(
-            actions
+impl TryFrom<&Vec<TcAction>> for FlowerActionList {
+    type Error = Error;
+
+    /// # Errors
+    /// Returns an error if the number of actions is greater than `u16::MAX - 1`.
+    fn try_from(actions: &Vec<TcAction>) -> Result<Self, Self::Error> {
+        if actions.len() > (u16::MAX - 1) as usize {
+            return Err(Error::msg(
+                "Too many actions for flower filter",
+            ));
+        };
+        Ok(Self(
             actions
                 .iter()
                 .enumerate()
                 .map(|(i, a)| FlowerAction {
-                    index: (i as u16) + 1,
+                    #[allow(clippy::cast_possible_truncation)]
+                    index: ((i & (u16::MAX as usize)) as u16) + 1,
                     data: a.clone(),
                 })
                 .collect::<Vec<_>>(),
-        )
+        ))
     }
 }
 
@@ -964,7 +973,9 @@ impl Nla for TcFilterFlowerOption {
             Self::ClassId(_) => 4,
             Self::Indev(b) => b.len(),
             Self::Action(acts) => {
-                FlowerActionList::from(acts).0.as_slice().buffer_len()
+                acts.as_slice().buffer_len()
+                // TODO: I despise this unwrap.
+                // FlowerActionList::try_from(acts).unwrap().0.as_slice().buffer_len()
             }
             Self::KeyEthDst(k) => k.as_slice().len(),
             Self::KeyEthDstMask(k) => k.as_slice().len(),
@@ -1198,7 +1209,7 @@ impl Nla for TcFilterFlowerOption {
             Self::Indev(b) => buffer.copy_from_slice(b.as_slice()),
             Self::ClassId(i) => NativeEndian::write_u32(buffer, (*i).into()),
             Self::Action(acts) => {
-                FlowerActionList::from(acts).0.as_slice().emit(buffer);
+                acts.as_slice().emit(buffer);
             }
             Self::KeyEthDst(k) => buffer.copy_from_slice(k.as_slice()),
             Self::KeyEthDstMask(k) => buffer.copy_from_slice(k.as_slice()),
@@ -1208,6 +1219,9 @@ impl Nla for TcFilterFlowerOption {
                 buffer.copy_from_slice(eth_type.as_be_bytes().as_slice());
             }
             Self::KeyIpProto(proto) => {
+                // TODO: find a way to make clippy happy with this.
+                // I think this is safe but that should be explained.
+                #[allow(clippy::cast_sign_loss, clippy::cast_possible_truncation)]
                 buffer.copy_from_slice(&[i32::from(*proto) as u8]);
             }
             Self::KeyIpv4Src(ip) => buffer.copy_from_slice(&ip.octets()),
@@ -1338,9 +1352,11 @@ impl Nla for TcFilterFlowerOption {
                 buffer.copy_from_slice(label.to_ne_bytes().as_slice());
             }
             Self::KeyTcpFlags(flags) => buffer.copy_from_slice(
+                #[allow(clippy::cast_lossless)]
                 (flags.bits() as u16).to_be_bytes().as_slice(),
             ),
             Self::KeyTcpFlagsMask(flags) => {
+                #[allow(clippy::cast_lossless)]
                 buffer.copy_from_slice((*flags as u16).to_be_bytes().as_slice());
             }
             Self::KeyIpTos(tos) => {
@@ -1497,10 +1513,8 @@ impl<'a, T: AsRef<[u8]> + ?Sized> Parseable<NlaBuffer<&'a T>>
                 Self::KeyEthType(EthType::from(eth_type))
             }
             TCA_FLOWER_KEY_IP_PROTO => {
-                if payload.len() != 1 {
-                    return Err(DecodeError::from("invalid ip proto length"));
-                }
-                let proto = IpProtocol::from(payload[0] as i32);
+                #[allow(clippy::cast_lossless)]
+                let proto = IpProtocol::from(parse_u8(payload)? as i32);
                 Self::KeyIpProto(proto)
             }
             TCA_FLOWER_KEY_IPV4_SRC => {