Support tc flower tcp flags mask

Author: daniel-noland

src/tc/filters/cls_flower.rs

@@ -210,6 +210,23 @@ pub type MplsTtl = u8;
 pub type MplsBos = u8;
 pub type MplsTc = u8;
 pub type MplsLabel = u32;
+pub type TcpFlagsMask = u8;
+
+bitflags! {
+    // TcpFlags _ARE_ exactly 8 bits.
+    // Why flower uses a 16-bit field is a mystery, but we deal with it.
+    #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+    pub struct TcpFlags : u8 {
+        const Cwr = 1 << 0;
+        const Ece = 1 << 1;
+        const Urg = 1 << 2;
+        const Ack = 1 << 3;
+        const Psh = 1 << 4;
+        const Rst = 1 << 5;
+        const Syn = 1 << 6;
+        const Fin = 1 << 7;
+    }
+}
 
 // Lists sourced from https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml
 pub mod icmpv4 {
@@ -1351,6 +1368,8 @@ pub enum TcFilterFlowerOption {
     KeyMplsBos(MplsBos),
     KeyMplsTc(MplsTc),
     KeyMplsLabel(MplsLabel),
+    KeyTcpFlags(TcpFlags),
+    KeyTcpFlagsMask(TcpFlagsMask),
 }
 
 impl Nla for TcFilterFlowerOption {
@@ -1424,6 +1443,8 @@ impl Nla for TcFilterFlowerOption {
             Self::KeyMplsBos(_) => 1,
             Self::KeyMplsTc(_) => 1,
             Self::KeyMplsLabel(_) => 4,
+            Self::KeyTcpFlags(_) => 2,
+            Self::KeyTcpFlagsMask(_) => 2,
             Self::Other(attr) => attr.value_len(),
         }
     }
@@ -1502,6 +1523,8 @@ impl Nla for TcFilterFlowerOption {
             Self::KeyMplsBos(_) => TCA_FLOWER_KEY_MPLS_BOS,
             Self::KeyMplsTc(_) => TCA_FLOWER_KEY_MPLS_TC,
             Self::KeyMplsLabel(_) => TCA_FLOWER_KEY_MPLS_LABEL,
+            Self::KeyTcpFlags(_) => TCA_FLOWER_KEY_TCP_FLAGS,
+            Self::KeyTcpFlagsMask(_) => TCA_FLOWER_KEY_TCP_FLAGS_MASK,
             Self::Other(attr) => attr.kind(),
         }
     }
@@ -1519,7 +1542,7 @@ impl Nla for TcFilterFlowerOption {
                 buffer.copy_from_slice(eth_type.as_be_bytes().as_slice())
             }
             Self::KeyIpProto(proto) => {
-                buffer.copy_from_slice(&[(i32::from(*proto) as u8)])
+                buffer.copy_from_slice(&[i32::from(*proto) as u8])
             }
             Self::KeyIpv4Src(ip) => buffer.copy_from_slice(&ip.octets()),
             Self::KeyIpv4SrcMask(ip) => buffer.copy_from_slice(&ip.octets()),
@@ -1647,6 +1670,12 @@ impl Nla for TcFilterFlowerOption {
                 // but nothing works unless it's native endian.  Bug report?
                 buffer.copy_from_slice(label.to_ne_bytes().as_slice())
             }
+            Self::KeyTcpFlags(flags) => buffer.copy_from_slice(
+                (flags.bits() as u16).to_be_bytes().as_slice(),
+            ),
+            Self::KeyTcpFlagsMask(flags) => {
+                buffer.copy_from_slice((*flags as u16).to_be_bytes().as_slice())
+            }
             Self::Other(attr) => attr.emit_value(buffer),
         }
     }
@@ -2232,6 +2261,22 @@ impl<'a, T: AsRef<[u8]> + ?Sized> Parseable<NlaBuffer<&'a T>>
                 let label = BigEndian::read_u32(payload);
                 Self::KeyMplsLabel(label)
             }
+            TCA_FLOWER_KEY_TCP_FLAGS => {
+                if payload.len() != 2 {
+                    return Err(DecodeError::from("invalid tcp flags length"));
+                }
+                let flags = BigEndian::read_u16(payload);
+                Self::KeyTcpFlags(TcpFlags::from_bits_retain(flags as u8))
+            }
+            TCA_FLOWER_KEY_TCP_FLAGS_MASK => {
+                if payload.len() != 2 {
+                    return Err(DecodeError::from(
+                        "invalid tcp flags mask length",
+                    ));
+                }
+                let flags = BigEndian::read_u16(payload);
+                Self::KeyTcpFlagsMask(flags as u8)
+            }
             _ => Self::Other(
                 DefaultNla::parse(buf).context("failed to parse flower nla")?,
             ),

src/tc/filters/mod.rs

@@ -13,7 +13,7 @@ pub use self::cls_u32::{
 pub use self::matchall::{TcFilterMatchAll, TcFilterMatchAllOption};
 pub use cls_flower::{
     arp, icmpv4, icmpv6, EncKeyId, EthType, TcFilterFlower,
-    TcFilterFlowerOption, VlanId, VlanPrio,
+    TcFilterFlowerOption, TcpFlags, VlanId, VlanPrio,
 };
 pub use flower_flags::TcFlowerOptionFlags;
 pub use u32_flags::{TcU32OptionFlags, TcU32SelectorFlags};

src/tc/mod.rs

@@ -11,7 +11,8 @@ pub use self::filters::{
     arp, icmpv4, icmpv6, EncKeyId, EthType, TcFilterFlower,
     TcFilterFlowerOption, TcFilterMatchAll, TcFilterMatchAllOption,
     TcFilterU32, TcFilterU32Option, TcFlowerOptionFlags, TcU32Key,
-    TcU32OptionFlags, TcU32Selector, TcU32SelectorFlags, VlanId, VlanPrio,
+    TcU32OptionFlags, TcU32Selector, TcU32SelectorFlags, TcpFlags, VlanId,
+    VlanPrio,
 };
 pub use self::header::{TcHandle, TcHeader, TcMessageBuffer};
 pub use self::message::TcMessage;