First pass constification of the wire module

src/wire/arp.rs

@@ -39,25 +39,25 @@ mod field {
     pub const OPER: Field = 6..8;
 
     #[inline]
-    pub fn SHA(hardware_len: u8, _protocol_len: u8) -> Field {
+    pub const fn SHA(hardware_len: u8, _protocol_len: u8) -> Field {
         let start = OPER.end;
         start..(start + hardware_len as usize)
     }
 
     #[inline]
-    pub fn SPA(hardware_len: u8, protocol_len: u8) -> Field {
+    pub const fn SPA(hardware_len: u8, protocol_len: u8) -> Field {
         let start = SHA(hardware_len, protocol_len).end;
         start..(start + protocol_len as usize)
     }
 
     #[inline]
-    pub fn THA(hardware_len: u8, protocol_len: u8) -> Field {
+    pub const fn THA(hardware_len: u8, protocol_len: u8) -> Field {
         let start = SPA(hardware_len, protocol_len).end;
         start..(start + hardware_len as usize)
     }
 
     #[inline]
-    pub fn TPA(hardware_len: u8, protocol_len: u8) -> Field {
+    pub const fn TPA(hardware_len: u8, protocol_len: u8) -> Field {
         let start = THA(hardware_len, protocol_len).end;
         start..(start + protocol_len as usize)
     }
@@ -65,7 +65,7 @@ mod field {
 
 impl<T: AsRef<[u8]>> Packet<T> {
     /// Imbue a raw octet buffer with ARP packet structure.
-    pub fn new_unchecked(buffer: T) -> Packet<T> {
+    pub const fn new_unchecked(buffer: T) -> Packet<T> {
         Packet { buffer }
     }
 
@@ -289,7 +289,7 @@ impl Repr {
     }
 
     /// Return the length of a packet that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         match *self {
             Repr::EthernetIpv4 { .. } => field::TPA(6, 4).end,
         }

src/wire/dhcpv4.rs

@@ -44,7 +44,7 @@ bitflags! {
 }
 
 impl MessageType {
-    fn opcode(&self) -> OpCode {
+    const fn opcode(&self) -> OpCode {
         match *self {
             MessageType::Discover
             | MessageType::Inform
@@ -233,7 +233,7 @@ pub(crate) mod field {
 
 impl<T: AsRef<[u8]>> Packet<T> {
     /// Imbue a raw octet buffer with DHCP packet structure.
-    pub fn new_unchecked(buffer: T) -> Packet<T> {
+    pub const fn new_unchecked(buffer: T) -> Packet<T> {
         Packet { buffer }
     }
 
@@ -1143,7 +1143,7 @@ mod test {
         assert_eq!(packet, DISCOVER_BYTES);
     }
 
-    fn offer_repr() -> Repr<'static> {
+    const fn offer_repr() -> Repr<'static> {
         Repr {
             message_type: MessageType::Offer,
             transaction_id: 0x3d1d,
@@ -1169,7 +1169,7 @@ mod test {
         }
     }
 
-    fn discover_repr() -> Repr<'static> {
+    const fn discover_repr() -> Repr<'static> {
         Repr {
             message_type: MessageType::Discover,
             transaction_id: 0x3d1d,

src/wire/dns.rs

@@ -83,7 +83,7 @@ pub struct Packet<T: AsRef<[u8]>> {
 
 impl<T: AsRef<[u8]>> Packet<T> {
     /// Imbue a raw octet buffer with DNS packet structure.
-    pub fn new_unchecked(buffer: T) -> Packet<T> {
+    pub const fn new_unchecked(buffer: T) -> Packet<T> {
         Packet { buffer }
     }
 
@@ -311,7 +311,7 @@ impl<'a> Question<'a> {
     }
 
     /// Return the length of a packet that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         self.name.len() + 4
     }
 
@@ -412,7 +412,7 @@ pub struct Repr<'a> {
 
 impl<'a> Repr<'a> {
     /// Return the length of a packet that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         field::HEADER_END + self.question.buffer_len()
     }
 

src/wire/ethernet.rs

@@ -43,7 +43,7 @@ impl Address {
     }
 
     /// Return an Ethernet address as a sequence of octets, in big-endian.
-    pub fn as_bytes(&self) -> &[u8] {
+    pub const fn as_bytes(&self) -> &[u8] {
         &self.0
     }
 
@@ -58,12 +58,12 @@ impl Address {
     }
 
     /// Query whether the "multicast" bit in the OUI is set.
-    pub fn is_multicast(&self) -> bool {
+    pub const fn is_multicast(&self) -> bool {
         self.0[0] & 0x01 != 0
     }
 
     /// Query whether the "locally administered" bit in the OUI is set.
-    pub fn is_local(&self) -> bool {
+    pub const fn is_local(&self) -> bool {
         self.0[0] & 0x02 != 0
     }
 }
@@ -100,7 +100,7 @@ pub const HEADER_LEN: usize = field::PAYLOAD.start;
 
 impl<T: AsRef<[u8]>> Frame<T> {
     /// Imbue a raw octet buffer with Ethernet frame structure.
-    pub fn new_unchecked(buffer: T) -> Frame<T> {
+    pub const fn new_unchecked(buffer: T) -> Frame<T> {
         Frame { buffer }
     }
 
@@ -131,13 +131,13 @@ impl<T: AsRef<[u8]>> Frame<T> {
     }
 
     /// Return the length of a frame header.
-    pub fn header_len() -> usize {
+    pub const fn header_len() -> usize {
         HEADER_LEN
     }
 
     /// Return the length of a buffer required to hold a packet with the payload
     /// of a given length.
-    pub fn buffer_len(payload_len: usize) -> usize {
+    pub const fn buffer_len(payload_len: usize) -> usize {
         HEADER_LEN + payload_len
     }
 
@@ -277,7 +277,7 @@ impl Repr {
     }
 
     /// Return the length of a header that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         HEADER_LEN
     }
 

src/wire/icmpv4.rs

@@ -184,7 +184,7 @@ mod field {
 
 impl<T: AsRef<[u8]>> Packet<T> {
     /// Imbue a raw octet buffer with ICMPv4 packet structure.
-    pub fn new_unchecked(buffer: T) -> Packet<T> {
+    pub const fn new_unchecked(buffer: T) -> Packet<T> {
         Packet { buffer }
     }
 
@@ -468,7 +468,7 @@ impl<'a> Repr<'a> {
     }
 
     /// Return the length of a packet that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         match self {
             &Repr::EchoRequest { data, .. } | &Repr::EchoReply { data, .. } => {
                 field::ECHO_SEQNO.end + data.len()

src/wire/icmpv6.rs

@@ -55,7 +55,7 @@ impl Message {
     /// is an [NDISC] message type.
     ///
     /// [NDISC]: https://tools.ietf.org/html/rfc4861
-    pub fn is_ndisc(&self) -> bool {
+    pub const fn is_ndisc(&self) -> bool {
         match *self {
             Message::RouterSolicit
             | Message::RouterAdvert
@@ -70,7 +70,7 @@ impl Message {
     /// is an [MLD] message type.
     ///
     /// [MLD]: https://tools.ietf.org/html/rfc3810
-    pub fn is_mld(&self) -> bool {
+    pub const fn is_mld(&self) -> bool {
         match *self {
             Message::MldQuery | Message::MldReport => true,
             _ => false,
@@ -247,7 +247,7 @@ pub(super) mod field {
 
 impl<T: AsRef<[u8]>> Packet<T> {
     /// Imbue a raw octet buffer with ICMPv6 packet structure.
-    pub fn new_unchecked(buffer: T) -> Packet<T> {
+    pub const fn new_unchecked(buffer: T) -> Packet<T> {
         Packet { buffer }
     }
 
@@ -625,7 +625,7 @@ impl<'a> Repr<'a> {
     }
 
     /// Return the length of a packet that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         match self {
             &Repr::DstUnreachable { header, data, .. }
             | &Repr::PktTooBig { header, data, .. }

src/wire/ieee802154.rs

@@ -43,7 +43,7 @@ enum_with_unknown! {
 
 impl AddressingMode {
     /// Return the size in octets of the address.
-    fn size(&self) -> usize {
+    const fn size(&self) -> usize {
         match self {
             AddressingMode::Absent => 0,
             AddressingMode::Short => 2,
@@ -103,11 +103,11 @@ impl Address {
         *self == Self::BROADCAST
     }
 
-    fn short_from_bytes(a: [u8; 2]) -> Self {
+    const fn short_from_bytes(a: [u8; 2]) -> Self {
         Self::Short(a)
     }
 
-    fn extended_from_bytes(a: [u8; 8]) -> Self {
+    const fn extended_from_bytes(a: [u8; 8]) -> Self {
         Self::Extended(a)
     }
 
@@ -125,7 +125,7 @@ impl Address {
         }
     }
 
-    pub fn as_bytes(&self) -> &[u8] {
+    pub const fn as_bytes(&self) -> &[u8] {
         match self {
             Address::Absent => &[],
             Address::Short(value) => value,
@@ -224,7 +224,7 @@ macro_rules! set_fc_bit_field {
 
 impl<T: AsRef<[u8]>> Frame<T> {
     /// Input a raw octet buffer with Ethernet frame structure.
-    pub fn new_unchecked(buffer: T) -> Frame<T> {
+    pub const fn new_unchecked(buffer: T) -> Frame<T> {
         Frame { buffer }
     }
 
@@ -784,7 +784,7 @@ impl Repr {
 
     /// Return the length of a buffer required to hold a packet with the payload of a given length.
     #[inline]
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         3 + 2
             + match self.dst_addr {
                 Some(Address::Absent) | None => 0,

src/wire/igmp.rs

@@ -54,7 +54,7 @@ impl fmt::Display for Message {
 /// [RFC 2236]: https://tools.ietf.org/html/rfc2236
 impl<T: AsRef<[u8]>> Packet<T> {
     /// Imbue a raw octet buffer with IGMPv2 packet structure.
-    pub fn new_unchecked(buffer: T) -> Packet<T> {
+    pub const fn new_unchecked(buffer: T) -> Packet<T> {
         Packet { buffer }
     }
 
@@ -246,7 +246,7 @@ impl Repr {
     }
 
     /// Return the length of a packet that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         // always 8 bytes
         field::GROUP_ADDRESS.end
     }
@@ -304,7 +304,7 @@ fn max_resp_code_to_duration(value: u8) -> Duration {
     Duration::from_millis(decisecs * 100)
 }
 
-fn duration_to_max_resp_code(duration: Duration) -> u8 {
+const fn duration_to_max_resp_code(duration: Duration) -> u8 {
     let decisecs = duration.total_millis() / 100;
     if decisecs < 128 {
         decisecs as u8

src/wire/ip.rs

@@ -23,7 +23,7 @@ impl Version {
     ///
     /// This function never returns `Ok(IpVersion::Unspecified)`; instead,
     /// unknown versions result in `Err(Error)`.
-    pub fn of_packet(data: &[u8]) -> Result<Version> {
+    pub const fn of_packet(data: &[u8]) -> Result<Version> {
         match data[0] >> 4 {
             #[cfg(feature = "proto-ipv4")]
             4 => Ok(Version::Ipv4),
@@ -93,7 +93,7 @@ pub enum Address {
 impl Address {
     /// Create an address wrapping an IPv4 address with the given octets.
     #[cfg(feature = "proto-ipv4")]
-    pub fn v4(a0: u8, a1: u8, a2: u8, a3: u8) -> Address {
+    pub const fn v4(a0: u8, a1: u8, a2: u8, a3: u8) -> Address {
         Address::Ipv4(Ipv4Address::new(a0, a1, a2, a3))
     }
 
@@ -105,7 +105,7 @@ impl Address {
     }
 
     /// Return the protocol version.
-    pub fn version(&self) -> Version {
+    pub const fn version(&self) -> Version {
         match self {
             #[cfg(feature = "proto-ipv4")]
             Address::Ipv4(_) => Version::Ipv4,
@@ -115,7 +115,7 @@ impl Address {
     }
 
     /// Return an address as a sequence of octets, in big-endian.
-    pub fn as_bytes(&self) -> &[u8] {
+    pub const fn as_bytes(&self) -> &[u8] {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Address::Ipv4(ref addr) => addr.as_bytes(),
@@ -135,7 +135,7 @@ impl Address {
     }
 
     /// Query whether the address is a valid multicast address.
-    pub fn is_multicast(&self) -> bool {
+    pub const fn is_multicast(&self) -> bool {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Address::Ipv4(addr) => addr.is_multicast(),
@@ -289,7 +289,7 @@ impl Cidr {
     }
 
     /// Return the IP address of this CIDR block.
-    pub fn address(&self) -> Address {
+    pub const fn address(&self) -> Address {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Cidr::Ipv4(cidr) => Address::Ipv4(cidr.address()),
@@ -299,7 +299,7 @@ impl Cidr {
     }
 
     /// Return the prefix length of this CIDR block.
-    pub fn prefix_len(&self) -> u8 {
+    pub const fn prefix_len(&self) -> u8 {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Cidr::Ipv4(cidr) => cidr.prefix_len(),
@@ -386,7 +386,7 @@ pub struct Endpoint {
 
 impl Endpoint {
     /// Create an endpoint address from given address and port.
-    pub fn new(addr: Address, port: u16) -> Endpoint {
+    pub const fn new(addr: Address, port: u16) -> Endpoint {
         Endpoint { addr: addr, port }
     }
 }
@@ -457,7 +457,7 @@ pub struct ListenEndpoint {
 
 impl ListenEndpoint {
     /// Query whether the endpoint has a specified address and port.
-    pub fn is_specified(&self) -> bool {
+    pub const fn is_specified(&self) -> bool {
         self.addr.is_some() && self.port != 0
     }
 }
@@ -596,7 +596,7 @@ impl Repr {
     }
 
     /// Return the protocol version.
-    pub fn version(&self) -> Version {
+    pub const fn version(&self) -> Version {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Repr::Ipv4(_) => Version::Ipv4,
@@ -606,7 +606,7 @@ impl Repr {
     }
 
     /// Return the source address.
-    pub fn src_addr(&self) -> Address {
+    pub const fn src_addr(&self) -> Address {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Repr::Ipv4(repr) => Address::Ipv4(repr.src_addr),
@@ -616,7 +616,7 @@ impl Repr {
     }
 
     /// Return the destination address.
-    pub fn dst_addr(&self) -> Address {
+    pub const fn dst_addr(&self) -> Address {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Repr::Ipv4(repr) => Address::Ipv4(repr.dst_addr),
@@ -626,7 +626,7 @@ impl Repr {
     }
 
     /// Return the next header (protocol).
-    pub fn next_header(&self) -> Protocol {
+    pub const fn next_header(&self) -> Protocol {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Repr::Ipv4(repr) => repr.next_header,
@@ -636,7 +636,7 @@ impl Repr {
     }
 
     /// Return the payload length.
-    pub fn payload_len(&self) -> usize {
+    pub const fn payload_len(&self) -> usize {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Repr::Ipv4(repr) => repr.payload_len,
@@ -656,7 +656,7 @@ impl Repr {
     }
 
     /// Return the TTL value.
-    pub fn hop_limit(&self) -> u8 {
+    pub const fn hop_limit(&self) -> u8 {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Repr::Ipv4(Ipv4Repr { hop_limit, .. }) => hop_limit,
@@ -666,7 +666,7 @@ impl Repr {
     }
 
     /// Return the length of a header that will be emitted from this high-level representation.
-    pub fn header_len(&self) -> usize {
+    pub const fn header_len(&self) -> usize {
         match *self {
             #[cfg(feature = "proto-ipv4")]
             Repr::Ipv4(repr) => repr.buffer_len(),
@@ -693,7 +693,7 @@ impl Repr {
     /// high-level representation.
     ///
     /// This is the same as `repr.buffer_len() + repr.payload_len()`.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         self.header_len() + self.payload_len()
     }
 }
@@ -703,7 +703,7 @@ pub mod checksum {
 
     use super::*;
 
-    fn propagate_carries(word: u32) -> u16 {
+    const fn propagate_carries(word: u32) -> u16 {
         let sum = (word >> 16) + (word & 0xffff);
         ((sum >> 16) as u16) + (sum as u16)
     }

src/wire/ipv4.rs

@@ -67,7 +67,7 @@ impl Address {
     }
 
     /// Return an IPv4 address as a sequence of octets, in big-endian.
-    pub fn as_bytes(&self) -> &[u8] {
+    pub const fn as_bytes(&self) -> &[u8] {
         &self.0
     }
 
@@ -192,7 +192,7 @@ impl Cidr {
     }
 
     /// Return the network mask of this IPv4 CIDR.
-    pub fn netmask(&self) -> Address {
+    pub const fn netmask(&self) -> Address {
         if self.prefix_len == 0 {
             return Address([0, 0, 0, 0]);
         }
@@ -229,7 +229,7 @@ impl Cidr {
     }
 
     /// Return the network block of this IPv4 CIDR.
-    pub fn network(&self) -> Cidr {
+    pub const fn network(&self) -> Cidr {
         let mask = self.netmask().0;
         let network = [
             self.address.0[0] & mask[0],
@@ -303,7 +303,7 @@ pub const HEADER_LEN: usize = field::DST_ADDR.end;
 
 impl<T: AsRef<[u8]>> Packet<T> {
     /// Imbue a raw octet buffer with IPv4 packet structure.
-    pub fn new_unchecked(buffer: T) -> Packet<T> {
+    pub const fn new_unchecked(buffer: T) -> Packet<T> {
         Packet { buffer }
     }
 
@@ -662,7 +662,7 @@ impl Repr {
     }
 
     /// Return the length of a header that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         // We never emit any options.
         field::DST_ADDR.end
     }
@@ -880,7 +880,7 @@ mod test {
 
     static REPR_PAYLOAD_BYTES: [u8; ADDR_SIZE] = [0xaa, 0x00, 0x00, 0xff];
 
-    fn packet_repr() -> Repr {
+    const fn packet_repr() -> Repr {
         Repr {
             src_addr: Address([0x11, 0x12, 0x13, 0x14]),
             dst_addr: Address([0x21, 0x22, 0x23, 0x24]),

src/wire/ipv6.rs

@@ -116,7 +116,7 @@ impl Address {
     }
 
     /// Return an IPv6 address as a sequence of octets, in big-endian.
-    pub fn as_bytes(&self) -> &[u8] {
+    pub const fn as_bytes(&self) -> &[u8] {
         &self.0
     }
 
@@ -130,7 +130,7 @@ impl Address {
     /// Query whether the IPv6 address is a [multicast address].
     ///
     /// [multicast address]: https://tools.ietf.org/html/rfc4291#section-2.7
-    pub fn is_multicast(&self) -> bool {
+    pub const fn is_multicast(&self) -> bool {
         self.0[0] == 0xff
     }
 
@@ -333,12 +333,12 @@ impl Cidr {
     }
 
     /// Return the address of this IPv6 CIDR block.
-    pub fn address(&self) -> Address {
+    pub const fn address(&self) -> Address {
         self.address
     }
 
     /// Return the prefix length of this IPv6 CIDR block.
-    pub fn prefix_len(&self) -> u8 {
+    pub const fn prefix_len(&self) -> u8 {
         self.prefix_len
     }
 
@@ -425,7 +425,7 @@ pub const HEADER_LEN: usize = field::DST_ADDR.end;
 impl<T: AsRef<[u8]>> Packet<T> {
     /// Create a raw octet buffer with an IPv6 packet structure.
     #[inline]
-    pub fn new_unchecked(buffer: T) -> Packet<T> {
+    pub const fn new_unchecked(buffer: T) -> Packet<T> {
         Packet { buffer }
     }
 
@@ -464,7 +464,7 @@ impl<T: AsRef<[u8]>> Packet<T> {
 
     /// Return the header length.
     #[inline]
-    pub fn header_len(&self) -> usize {
+    pub const fn header_len(&self) -> usize {
         // This is not a strictly necessary function, but it makes
         // code more readable.
         field::DST_ADDR.end
@@ -670,7 +670,7 @@ impl Repr {
     }
 
     /// Return the length of a header that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         // This function is not strictly necessary, but it can make client code more readable.
         field::DST_ADDR.end
     }
@@ -1055,7 +1055,7 @@ mod test {
         0x00, 0x01, 0x00, 0x02, 0x00, 0x0c, 0x02, 0x4e, 0xff, 0xff, 0xff, 0xff,
     ];
 
-    fn packet_repr() -> Repr {
+    const fn packet_repr() -> Repr {
         Repr {
             src_addr: Address([
                 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

src/wire/ipv6fragment.rs

@@ -36,7 +36,7 @@ mod field {
 
 impl<T: AsRef<[u8]>> Header<T> {
     /// Create a raw octet buffer with an IPv6 Fragment Header structure.
-    pub fn new_unchecked(buffer: T) -> Header<T> {
+    pub const fn new_unchecked(buffer: T) -> Header<T> {
         Header { buffer }
     }
 
@@ -188,7 +188,7 @@ impl Repr {
 
     /// Return the length, in bytes, of a header that will be emitted from this high-level
     /// representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         field::IDENT.end
     }
 

src/wire/ipv6hopbyhop.rs

@@ -42,7 +42,7 @@ mod field {
     //
     // Length of the header is in 8-octet units, not including the first 8 octets. The first two
     // octets are the next header type and the header length.
-    pub fn OPTIONS(length_field: u8) -> Field {
+    pub const fn OPTIONS(length_field: u8) -> Field {
         let bytes = length_field as usize * 8 + 8;
         2..bytes
     }
@@ -50,7 +50,7 @@ mod field {
 
 impl<T: AsRef<[u8]>> Header<T> {
     /// Create a raw octet buffer with an IPv6 Hop-by-Hop Options Header structure.
-    pub fn new_unchecked(buffer: T) -> Header<T> {
+    pub const fn new_unchecked(buffer: T) -> Header<T> {
         Header { buffer }
     }
 
@@ -183,7 +183,7 @@ impl<'a> Repr<'a> {
 
     /// Return the length, in bytes, of a header that will be emitted from this high-level
     /// representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         field::OPTIONS(self.length).end
     }
 

src/wire/ipv6option.rs

@@ -81,14 +81,14 @@ mod field {
     // 8-bit unsigned integer. Length of the DATA field of this option, in octets.
     pub const LENGTH: usize = 1;
     // Variable-length field. Option-Type-specific data.
-    pub fn DATA(length: u8) -> Field {
+    pub const fn DATA(length: u8) -> Field {
         2..length as usize + 2
     }
 }
 
 impl<T: AsRef<[u8]>> Ipv6Option<T> {
     /// Create a raw octet buffer with an IPv6 Extension Header Option structure.
-    pub fn new_unchecked(buffer: T) -> Ipv6Option<T> {
+    pub const fn new_unchecked(buffer: T) -> Ipv6Option<T> {
         Ipv6Option { buffer }
     }
 
@@ -245,7 +245,7 @@ impl<'a> Repr<'a> {
     }
 
     /// Return the length of a header that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         match *self {
             Repr::Pad1 => 1,
             Repr::PadN(length) => field::DATA(length).end,

src/wire/ipv6routing.rs

@@ -91,7 +91,7 @@ mod field {
     //
     // Length of the header is in 8-octet units, not including the first 8 octets. The first four
     // octets are the next header type, the header length, routing type and segments left.
-    pub fn DATA(length_field: u8) -> Field {
+    pub const fn DATA(length_field: u8) -> Field {
         let bytes = length_field as usize * 8 + 8;
         4..bytes
     }
@@ -134,7 +134,7 @@ mod field {
     // 8-bit field containing the Pad value.
     pub const PAD: usize = 5;
     // Variable length field containing addresses
-    pub fn ADDRESSES(length_field: u8) -> Field {
+    pub const fn ADDRESSES(length_field: u8) -> Field {
         let data = DATA(length_field);
         8..data.end
     }
@@ -143,7 +143,7 @@ mod field {
 /// Core getter methods relevant to any routing type.
 impl<T: AsRef<[u8]>> Header<T> {
     /// Create a raw octet buffer with an IPv6 Routing Header structure.
-    pub fn new(buffer: T) -> Header<T> {
+    pub const fn new(buffer: T) -> Header<T> {
         Header { buffer }
     }
 
@@ -457,7 +457,7 @@ impl<'a> Repr<'a> {
 
     /// Return the length, in bytes, of a header that will be emitted from this high-level
     /// representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         match self {
             &Repr::Rpl { length, .. } | &Repr::Type2 { length, .. } => field::DATA(length).end,
         }

src/wire/mld.rs

@@ -173,7 +173,7 @@ pub struct AddressRecord<T: AsRef<[u8]>> {
 
 impl<T: AsRef<[u8]>> AddressRecord<T> {
     /// Imbue a raw octet buffer with a Address Record structure.
-    pub fn new_unchecked(buffer: T) -> Self {
+    pub const fn new_unchecked(buffer: T) -> Self {
         Self { buffer }
     }
 
@@ -338,7 +338,7 @@ impl<'a> Repr<'a> {
     }
 
     /// Return the length of a packet that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         match self {
             Repr::Query { data, .. } => field::QUERY_NUM_SRCS.end + data.len(),
             Repr::Report { data, .. } => field::NR_MCAST_RCRDS.end + data.len(),

src/wire/mod.rs

@@ -284,7 +284,7 @@ pub enum HardwareAddress {
 
 #[cfg(any(feature = "medium-ethernet", feature = "medium-ieee802154"))]
 impl HardwareAddress {
-    pub fn as_bytes(&self) -> &[u8] {
+    pub const fn as_bytes(&self) -> &[u8] {
         match self {
             #[cfg(feature = "medium-ethernet")]
             HardwareAddress::Ethernet(addr) => addr.as_bytes(),
@@ -372,11 +372,11 @@ impl RawHardwareAddress {
         &self.data[..self.len as usize]
     }
 
-    pub fn len(&self) -> usize {
+    pub const fn len(&self) -> usize {
         self.len as usize
     }
 
-    pub fn is_empty(&self) -> bool {
+    pub const fn is_empty(&self) -> bool {
         self.len == 0
     }
 

src/wire/ndisc.rs

@@ -351,7 +351,7 @@ impl<'a> Repr<'a> {
         }
     }
 
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         match self {
             &Repr::RouterSolicit { lladdr } => match lladdr {
                 Some(addr) => {

src/wire/ndiscoption.rs

@@ -75,7 +75,7 @@ mod field {
     // Minimum length of an option.
     pub const MIN_OPT_LEN: usize = 8;
     // Variable-length field. Option-Type-specific data.
-    pub fn DATA(length: u8) -> Field {
+    pub const fn DATA(length: u8) -> Field {
         2..length as usize * 8
     }
 
@@ -145,7 +145,7 @@ mod field {
 /// Core getter methods relevant to any type of NDISC option.
 impl<T: AsRef<[u8]>> NdiscOption<T> {
     /// Create a raw octet buffer with an NDISC Option structure.
-    pub fn new_unchecked(buffer: T) -> NdiscOption<T> {
+    pub const fn new_unchecked(buffer: T) -> NdiscOption<T> {
         NdiscOption { buffer }
     }
 
@@ -499,7 +499,7 @@ impl<'a> Repr<'a> {
     }
 
     /// Return the length of a header that will be emitted from this high-level representation.
-    pub fn buffer_len(&self) -> usize {
+    pub const fn buffer_len(&self) -> usize {
         match self {
             &Repr::SourceLinkLayerAddr(addr) | &Repr::TargetLinkLayerAddr(addr) => {
                 let len = 2 + addr.len();

src/wire/sixlowpan.rs

@@ -282,7 +282,7 @@ pub mod frag {
 
     impl<T: AsRef<[u8]>> Packet<T> {
         /// Input a raw octet buffer with a 6LoWPAN Fragment header structure.
-        pub fn new_unchecked(buffer: T) -> Self {
+        pub const fn new_unchecked(buffer: T) -> Self {
             Self { buffer }
         }
 
@@ -445,7 +445,7 @@ pub mod frag {
         }
 
         /// Returns the length of the Fragment header.
-        pub fn buffer_len(&self) -> usize {
+        pub const fn buffer_len(&self) -> usize {
             match self {
                 Self::FirstFragment { .. } => field::FIRST_FRAGMENT_REST.start,
                 Self::Fragment { .. } => field::NEXT_FRAGMENT_REST.start,
@@ -558,7 +558,7 @@ pub mod iphc {
 
     impl<T: AsRef<[u8]>> Packet<T> {
         /// Input a raw octet buffer with a 6LoWPAN IPHC header structure.
-        pub fn new_unchecked(buffer: T) -> Self {
+        pub const fn new_unchecked(buffer: T) -> Self {
             Packet { buffer }
         }
 
@@ -1526,7 +1526,7 @@ pub mod nhc {
 
     impl<T: AsRef<[u8]>> ExtHeaderPacket<T> {
         /// Input a raw octet buffer with a 6LoWPAN NHC Extension Header structure.
-        pub fn new_unchecked(buffer: T) -> Self {
+        pub const fn new_unchecked(buffer: T) -> Self {
             ExtHeaderPacket { buffer }
         }
 
@@ -1745,7 +1745,7 @@ pub mod nhc {
 
     impl<T: AsRef<[u8]>> UdpNhcPacket<T> {
         /// Input a raw octet buffer with a LOWPAN_NHC frame structure for UDP.
-        pub fn new_unchecked(buffer: T) -> Self {
+        pub const fn new_unchecked(buffer: T) -> Self {
             Self { buffer }
         }
 
@@ -1786,7 +1786,7 @@ pub mod nhc {
         get_field!(ports_field, 0b11, 0);
 
         /// Returns the index of the start of the next header compressed fields.
-        fn nhc_fields_start(&self) -> usize {
+        const fn nhc_fields_start(&self) -> usize {
             1
         }
 

src/wire/tcp.rs

@@ -87,7 +87,7 @@ mod field {
     pub const CHECKSUM: Field = 16..18;
     pub const URGENT: Field = 18..20;
 
-    pub fn OPTIONS(length: u8) -> Field {
+    pub const fn OPTIONS(length: u8) -> Field {
         URGENT.end..(length as usize)
     }
 
@@ -113,7 +113,7 @@ pub const HEADER_LEN: usize = field::URGENT.end;
 
 impl<T: AsRef<[u8]>> Packet<T> {
     /// Imbue a raw octet buffer with TCP packet structure.
-    pub fn new_unchecked(buffer: T) -> Packet<T> {
+    pub const fn new_unchecked(buffer: T) -> Packet<T> {
         Packet { buffer }
     }
 
@@ -753,7 +753,7 @@ pub enum Control {
 #[allow(clippy::len_without_is_empty)]
 impl Control {
     /// Return the length of a control flag, in terms of sequence space.
-    pub fn len(self) -> usize {
+    pub const fn len(self) -> usize {
         match self {
             Control::Syn | Control::Fin => 1,
             _ => 0,
@@ -761,7 +761,7 @@ impl Control {
     }
 
     /// Turn the PSH flag into no flag, and keep the rest as-is.
-    pub fn quash_psh(self) -> Control {
+    pub const fn quash_psh(self) -> Control {
         match self {
             Control::Psh => Control::None,
             _ => self,
@@ -971,12 +971,12 @@ impl<'a> Repr<'a> {
     }
 
     /// Return the length of the segment, in terms of sequence space.
-    pub fn segment_len(&self) -> usize {
+    pub const fn segment_len(&self) -> usize {
         self.payload.len() + self.control.len()
     }
 
     /// Return whether the segment has no flags set (except PSH) and no data.
-    pub fn is_empty(&self) -> bool {
+    pub const fn is_empty(&self) -> bool {
         match self.control {
             _ if !self.payload.is_empty() => false,
             Control::Syn | Control::Fin | Control::Rst => false,

src/wire/udp.rs

@@ -23,7 +23,7 @@ mod field {
     pub const LENGTH: Field = 4..6;
     pub const CHECKSUM: Field = 6..8;
 
-    pub fn PAYLOAD(length: u16) -> Field {
+    pub const fn PAYLOAD(length: u16) -> Field {
         CHECKSUM.end..(length as usize)
     }
 }
@@ -33,7 +33,7 @@ pub const HEADER_LEN: usize = field::CHECKSUM.end;
 #[allow(clippy::len_without_is_empty)]
 impl<T: AsRef<[u8]>> Packet<T> {
     /// Imbue a raw octet buffer with UDP packet structure.
-    pub fn new_unchecked(buffer: T) -> Packet<T> {
+    pub const fn new_unchecked(buffer: T) -> Packet<T> {
         Packet { buffer }
     }
 
@@ -246,7 +246,7 @@ impl Repr {
     }
 
     /// Return the length of the packet header that will be emitted from this high-level representation.
-    pub fn header_len(&self) -> usize {
+    pub const fn header_len(&self) -> usize {
         HEADER_LEN
     }